Smack: Simplified Mandatory Access Control Kernel
Smack is the Simplified Mandatory Access Control Kernel.
Smack implements mandatory access control (MAC) using labels
attached to tasks and data containers, including files, SVIPC,
and other tasks. Smack is a kernel based scheme that requires
an absolute minimum of application support and a very small
amount of configuration data.
Smack uses extended attributes and
provides a set of general mount options, borrowing technics used
elsewhere. Smack uses netlabel for CIPSO labeling. Smack provides
a pseudo-filesystem smackfs that is used for manipulation of
system Smack attributes.
The patch, patches for ls and sshd, a README, a startup script,
and x86 binaries for ls and sshd are also available on
http://www.schaufler-ca.com
Development has been done using Fedora Core 7 in a virtual machine
environment and on an old Sony laptop.
Smack provides mandatory access controls based on the label attached
to a task and the label attached to the object it is attempting to
access. Smack labels are deliberately short (1-23 characters) text
strings. Single character labels using special characters are reserved
for system use. The only operation applied to Smack labels is equality
comparison. No wildcards or expressions, regular or otherwise, are
used. Smack labels are composed of printable characters and may not
include "/".
A file always gets the Smack label of the task that created it.
Smack defines and uses these labels:
"*" - pronounced "star"
"_" - pronounced "floor"
"^" - pronounced "hat"
"?" - pronounced "huh"
The access rules enforced by Smack are, in order:
1. Any access requested by a task labeled "*" is denied.
2. A read or execute access requested by a task labeled "^"
is permitted.
3. A read or execute access requested on an object labeled "_"
is permitted.
4. Any access requested on an object labeled "*" is permitted.
5. Any access requested by a task on an object with the same
label is permitted.
6. Any access requested that is explicitly defined in the loaded
rule set is permitted.
7. Any other access is denied.
Rules may be explicitly defined by writing subject,object,access
triples to /smack/load.
Smack rule sets can be easily defined that describe Bell&LaPadula
sensitivity, Biba integrity, and a variety of interesting
configurations. Smack rule sets can be modified on the fly to
accommodate changes in the operating environment or even the time
of day.
Some practical use cases:
Hierarchical levels. The less common of the two usual uses
for MLS systems is to define hierarchical levels, often
unclassified, confidential, secret, and so on. To set up smack
to support this, these rules could be defined:
C Unclass rx
S C rx
S Unclass rx
TS S rx
TS C rx
TS Unclass rx
A TS process can read S, C, and Unclass data, but cannot write it.
An S process can read C and Unclass. Note that specifying that
TS can read S and S can read C does not imply TS can read C, it
has to be explicitly stated.
Non-hierarchical categories. This is the more common of the
usual uses for an MLS system. Since the default rule is that a
subject cannot access an object with a different label no
access rules are required to implement compartmentalization.
A case that the Bell & LaPadula policy does not allow is demonstrated
with this Smack access rule:
A case that Bell&LaPadula does not allow that Smack does:
ESPN ABC r
ABC ESPN r
On my portable video device I have two applications, one that
shows ABC programming and the other ESPN programming. ESPN wants
to show me sport stories that show up as news, and ABC will
only provide minimal information about a sports story if ESPN
is covering it. Each side can look at the other's info, neither
can change the other. Neither can see what FOX is up to, which
is just as well all things considered.
Another case that I especially like:
SatData Guard w
Guard Publish w
A program running with the Guard label opens a UDP socket and
accepts messages sent by a program running with a SatData label.
The Guard program inspects the message to ensure it is wholesome
and if it is sends it to a program running with the Publish label.
This program then puts the information passed in an appropriate
place. Note that the Guard program cannot write to a Publish
file system object because file system semanitic require read as
well as write.
The four cases (categories, levels, mutual read, guardbox) here
are all quite real, and problems I've been asked to solve over
the years. The first two are easy to do with traditonal MLS systems
while the last two you can't without invoking privilege, at least
for a while.
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Cc: Joshua Brindle <method@manicmethod.com>
Cc: Paul Moore <paul.moore@hp.com>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: Chris Wright <chrisw@sous-sol.org>
Cc: James Morris <jmorris@namei.org>
Cc: "Ahmed S. Darwish" <darwish.07@gmail.com>
Cc: Andrew G. Morgan <morgan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-05 06:29:50 +00:00
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/*
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* Simplified MAC Kernel (smack) security module
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*
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* This file contains the smack hook function implementations.
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*
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* Author:
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* Casey Schaufler <casey@schaufler-ca.com>
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*
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* Copyright (C) 2007 Casey Schaufler <casey@schaufler-ca.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2,
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* as published by the Free Software Foundation.
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*/
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#include <linux/xattr.h>
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#include <linux/pagemap.h>
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#include <linux/mount.h>
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#include <linux/stat.h>
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#include <linux/ext2_fs.h>
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#include <linux/kd.h>
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#include <asm/ioctls.h>
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#include <linux/tcp.h>
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#include <linux/udp.h>
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#include <linux/mutex.h>
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#include <linux/pipe_fs_i.h>
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#include <net/netlabel.h>
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#include <net/cipso_ipv4.h>
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#include "smack.h"
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/*
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* I hope these are the hokeyist lines of code in the module. Casey.
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*/
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#define DEVPTS_SUPER_MAGIC 0x1cd1
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#define SOCKFS_MAGIC 0x534F434B
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#define TMPFS_MAGIC 0x01021994
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/**
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* smk_fetch - Fetch the smack label from a file.
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* @ip: a pointer to the inode
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* @dp: a pointer to the dentry
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*
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* Returns a pointer to the master list entry for the Smack label
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* or NULL if there was no label to fetch.
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*/
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static char *smk_fetch(struct inode *ip, struct dentry *dp)
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{
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int rc;
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char in[SMK_LABELLEN];
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if (ip->i_op->getxattr == NULL)
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return NULL;
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rc = ip->i_op->getxattr(dp, XATTR_NAME_SMACK, in, SMK_LABELLEN);
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if (rc < 0)
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return NULL;
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return smk_import(in, rc);
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}
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/**
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* new_inode_smack - allocate an inode security blob
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* @smack: a pointer to the Smack label to use in the blob
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*
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* Returns the new blob or NULL if there's no memory available
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*/
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struct inode_smack *new_inode_smack(char *smack)
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{
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struct inode_smack *isp;
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isp = kzalloc(sizeof(struct inode_smack), GFP_KERNEL);
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if (isp == NULL)
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return NULL;
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isp->smk_inode = smack;
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isp->smk_flags = 0;
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mutex_init(&isp->smk_lock);
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return isp;
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}
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/*
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* LSM hooks.
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* We he, that is fun!
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*/
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/**
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* smack_ptrace - Smack approval on ptrace
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* @ptp: parent task pointer
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* @ctp: child task pointer
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*
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* Returns 0 if access is OK, an error code otherwise
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*
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* Do the capability checks, and require read and write.
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*/
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static int smack_ptrace(struct task_struct *ptp, struct task_struct *ctp)
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{
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int rc;
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rc = cap_ptrace(ptp, ctp);
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if (rc != 0)
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return rc;
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rc = smk_access(ptp->security, ctp->security, MAY_READWRITE);
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if (rc != 0 && __capable(ptp, CAP_MAC_OVERRIDE))
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return 0;
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return rc;
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}
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/**
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* smack_syslog - Smack approval on syslog
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* @type: message type
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*
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* Require that the task has the floor label
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*
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* Returns 0 on success, error code otherwise.
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*/
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static int smack_syslog(int type)
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{
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int rc;
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char *sp = current->security;
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rc = cap_syslog(type);
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if (rc != 0)
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return rc;
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if (capable(CAP_MAC_OVERRIDE))
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return 0;
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if (sp != smack_known_floor.smk_known)
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rc = -EACCES;
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return rc;
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}
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/*
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* Superblock Hooks.
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*/
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/**
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* smack_sb_alloc_security - allocate a superblock blob
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* @sb: the superblock getting the blob
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*
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* Returns 0 on success or -ENOMEM on error.
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*/
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static int smack_sb_alloc_security(struct super_block *sb)
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{
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struct superblock_smack *sbsp;
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sbsp = kzalloc(sizeof(struct superblock_smack), GFP_KERNEL);
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if (sbsp == NULL)
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return -ENOMEM;
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sbsp->smk_root = smack_known_floor.smk_known;
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sbsp->smk_default = smack_known_floor.smk_known;
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sbsp->smk_floor = smack_known_floor.smk_known;
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sbsp->smk_hat = smack_known_hat.smk_known;
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sbsp->smk_initialized = 0;
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spin_lock_init(&sbsp->smk_sblock);
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sb->s_security = sbsp;
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return 0;
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}
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/**
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* smack_sb_free_security - free a superblock blob
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* @sb: the superblock getting the blob
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*
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*/
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static void smack_sb_free_security(struct super_block *sb)
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{
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kfree(sb->s_security);
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sb->s_security = NULL;
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}
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/**
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* smack_sb_copy_data - copy mount options data for processing
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* @type: file system type
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* @orig: where to start
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* @smackopts
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*
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* Returns 0 on success or -ENOMEM on error.
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*
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* Copy the Smack specific mount options out of the mount
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* options list.
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*/
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2008-03-05 15:31:54 +00:00
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static int smack_sb_copy_data(char *orig, char *smackopts)
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Smack: Simplified Mandatory Access Control Kernel
Smack is the Simplified Mandatory Access Control Kernel.
Smack implements mandatory access control (MAC) using labels
attached to tasks and data containers, including files, SVIPC,
and other tasks. Smack is a kernel based scheme that requires
an absolute minimum of application support and a very small
amount of configuration data.
Smack uses extended attributes and
provides a set of general mount options, borrowing technics used
elsewhere. Smack uses netlabel for CIPSO labeling. Smack provides
a pseudo-filesystem smackfs that is used for manipulation of
system Smack attributes.
The patch, patches for ls and sshd, a README, a startup script,
and x86 binaries for ls and sshd are also available on
http://www.schaufler-ca.com
Development has been done using Fedora Core 7 in a virtual machine
environment and on an old Sony laptop.
Smack provides mandatory access controls based on the label attached
to a task and the label attached to the object it is attempting to
access. Smack labels are deliberately short (1-23 characters) text
strings. Single character labels using special characters are reserved
for system use. The only operation applied to Smack labels is equality
comparison. No wildcards or expressions, regular or otherwise, are
used. Smack labels are composed of printable characters and may not
include "/".
A file always gets the Smack label of the task that created it.
Smack defines and uses these labels:
"*" - pronounced "star"
"_" - pronounced "floor"
"^" - pronounced "hat"
"?" - pronounced "huh"
The access rules enforced by Smack are, in order:
1. Any access requested by a task labeled "*" is denied.
2. A read or execute access requested by a task labeled "^"
is permitted.
3. A read or execute access requested on an object labeled "_"
is permitted.
4. Any access requested on an object labeled "*" is permitted.
5. Any access requested by a task on an object with the same
label is permitted.
6. Any access requested that is explicitly defined in the loaded
rule set is permitted.
7. Any other access is denied.
Rules may be explicitly defined by writing subject,object,access
triples to /smack/load.
Smack rule sets can be easily defined that describe Bell&LaPadula
sensitivity, Biba integrity, and a variety of interesting
configurations. Smack rule sets can be modified on the fly to
accommodate changes in the operating environment or even the time
of day.
Some practical use cases:
Hierarchical levels. The less common of the two usual uses
for MLS systems is to define hierarchical levels, often
unclassified, confidential, secret, and so on. To set up smack
to support this, these rules could be defined:
C Unclass rx
S C rx
S Unclass rx
TS S rx
TS C rx
TS Unclass rx
A TS process can read S, C, and Unclass data, but cannot write it.
An S process can read C and Unclass. Note that specifying that
TS can read S and S can read C does not imply TS can read C, it
has to be explicitly stated.
Non-hierarchical categories. This is the more common of the
usual uses for an MLS system. Since the default rule is that a
subject cannot access an object with a different label no
access rules are required to implement compartmentalization.
A case that the Bell & LaPadula policy does not allow is demonstrated
with this Smack access rule:
A case that Bell&LaPadula does not allow that Smack does:
ESPN ABC r
ABC ESPN r
On my portable video device I have two applications, one that
shows ABC programming and the other ESPN programming. ESPN wants
to show me sport stories that show up as news, and ABC will
only provide minimal information about a sports story if ESPN
is covering it. Each side can look at the other's info, neither
can change the other. Neither can see what FOX is up to, which
is just as well all things considered.
Another case that I especially like:
SatData Guard w
Guard Publish w
A program running with the Guard label opens a UDP socket and
accepts messages sent by a program running with a SatData label.
The Guard program inspects the message to ensure it is wholesome
and if it is sends it to a program running with the Publish label.
This program then puts the information passed in an appropriate
place. Note that the Guard program cannot write to a Publish
file system object because file system semanitic require read as
well as write.
The four cases (categories, levels, mutual read, guardbox) here
are all quite real, and problems I've been asked to solve over
the years. The first two are easy to do with traditonal MLS systems
while the last two you can't without invoking privilege, at least
for a while.
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Cc: Joshua Brindle <method@manicmethod.com>
Cc: Paul Moore <paul.moore@hp.com>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: Chris Wright <chrisw@sous-sol.org>
Cc: James Morris <jmorris@namei.org>
Cc: "Ahmed S. Darwish" <darwish.07@gmail.com>
Cc: Andrew G. Morgan <morgan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-05 06:29:50 +00:00
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{
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char *cp, *commap, *otheropts, *dp;
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otheropts = (char *)get_zeroed_page(GFP_KERNEL);
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if (otheropts == NULL)
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return -ENOMEM;
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for (cp = orig, commap = orig; commap != NULL; cp = commap + 1) {
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if (strstr(cp, SMK_FSDEFAULT) == cp)
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dp = smackopts;
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else if (strstr(cp, SMK_FSFLOOR) == cp)
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dp = smackopts;
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else if (strstr(cp, SMK_FSHAT) == cp)
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dp = smackopts;
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else if (strstr(cp, SMK_FSROOT) == cp)
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dp = smackopts;
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else
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dp = otheropts;
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commap = strchr(cp, ',');
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if (commap != NULL)
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*commap = '\0';
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if (*dp != '\0')
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strcat(dp, ",");
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strcat(dp, cp);
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}
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strcpy(orig, otheropts);
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free_page((unsigned long)otheropts);
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return 0;
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}
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/**
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* smack_sb_kern_mount - Smack specific mount processing
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* @sb: the file system superblock
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* @data: the smack mount options
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*
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* Returns 0 on success, an error code on failure
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*/
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static int smack_sb_kern_mount(struct super_block *sb, void *data)
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{
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struct dentry *root = sb->s_root;
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struct inode *inode = root->d_inode;
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struct superblock_smack *sp = sb->s_security;
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struct inode_smack *isp;
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char *op;
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char *commap;
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char *nsp;
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spin_lock(&sp->smk_sblock);
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if (sp->smk_initialized != 0) {
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spin_unlock(&sp->smk_sblock);
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return 0;
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}
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sp->smk_initialized = 1;
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spin_unlock(&sp->smk_sblock);
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for (op = data; op != NULL; op = commap) {
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commap = strchr(op, ',');
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if (commap != NULL)
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*commap++ = '\0';
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|
|
|
|
|
if (strncmp(op, SMK_FSHAT, strlen(SMK_FSHAT)) == 0) {
|
|
|
|
op += strlen(SMK_FSHAT);
|
|
|
|
nsp = smk_import(op, 0);
|
|
|
|
if (nsp != NULL)
|
|
|
|
sp->smk_hat = nsp;
|
|
|
|
} else if (strncmp(op, SMK_FSFLOOR, strlen(SMK_FSFLOOR)) == 0) {
|
|
|
|
op += strlen(SMK_FSFLOOR);
|
|
|
|
nsp = smk_import(op, 0);
|
|
|
|
if (nsp != NULL)
|
|
|
|
sp->smk_floor = nsp;
|
|
|
|
} else if (strncmp(op, SMK_FSDEFAULT,
|
|
|
|
strlen(SMK_FSDEFAULT)) == 0) {
|
|
|
|
op += strlen(SMK_FSDEFAULT);
|
|
|
|
nsp = smk_import(op, 0);
|
|
|
|
if (nsp != NULL)
|
|
|
|
sp->smk_default = nsp;
|
|
|
|
} else if (strncmp(op, SMK_FSROOT, strlen(SMK_FSROOT)) == 0) {
|
|
|
|
op += strlen(SMK_FSROOT);
|
|
|
|
nsp = smk_import(op, 0);
|
|
|
|
if (nsp != NULL)
|
|
|
|
sp->smk_root = nsp;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Initialize the root inode.
|
|
|
|
*/
|
|
|
|
isp = inode->i_security;
|
|
|
|
if (isp == NULL)
|
|
|
|
inode->i_security = new_inode_smack(sp->smk_root);
|
|
|
|
else
|
|
|
|
isp->smk_inode = sp->smk_root;
|
|
|
|
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_sb_statfs - Smack check on statfs
|
|
|
|
* @dentry: identifies the file system in question
|
|
|
|
*
|
|
|
|
* Returns 0 if current can read the floor of the filesystem,
|
|
|
|
* and error code otherwise
|
|
|
|
*/
|
|
|
|
static int smack_sb_statfs(struct dentry *dentry)
|
|
|
|
{
|
|
|
|
struct superblock_smack *sbp = dentry->d_sb->s_security;
|
|
|
|
|
|
|
|
return smk_curacc(sbp->smk_floor, MAY_READ);
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_sb_mount - Smack check for mounting
|
|
|
|
* @dev_name: unused
|
|
|
|
* @nd: mount point
|
|
|
|
* @type: unused
|
|
|
|
* @flags: unused
|
|
|
|
* @data: unused
|
|
|
|
*
|
|
|
|
* Returns 0 if current can write the floor of the filesystem
|
|
|
|
* being mounted on, an error code otherwise.
|
|
|
|
*/
|
|
|
|
static int smack_sb_mount(char *dev_name, struct nameidata *nd,
|
|
|
|
char *type, unsigned long flags, void *data)
|
|
|
|
{
|
2008-02-15 03:34:32 +00:00
|
|
|
struct superblock_smack *sbp = nd->path.mnt->mnt_sb->s_security;
|
Smack: Simplified Mandatory Access Control Kernel
Smack is the Simplified Mandatory Access Control Kernel.
Smack implements mandatory access control (MAC) using labels
attached to tasks and data containers, including files, SVIPC,
and other tasks. Smack is a kernel based scheme that requires
an absolute minimum of application support and a very small
amount of configuration data.
Smack uses extended attributes and
provides a set of general mount options, borrowing technics used
elsewhere. Smack uses netlabel for CIPSO labeling. Smack provides
a pseudo-filesystem smackfs that is used for manipulation of
system Smack attributes.
The patch, patches for ls and sshd, a README, a startup script,
and x86 binaries for ls and sshd are also available on
http://www.schaufler-ca.com
Development has been done using Fedora Core 7 in a virtual machine
environment and on an old Sony laptop.
Smack provides mandatory access controls based on the label attached
to a task and the label attached to the object it is attempting to
access. Smack labels are deliberately short (1-23 characters) text
strings. Single character labels using special characters are reserved
for system use. The only operation applied to Smack labels is equality
comparison. No wildcards or expressions, regular or otherwise, are
used. Smack labels are composed of printable characters and may not
include "/".
A file always gets the Smack label of the task that created it.
Smack defines and uses these labels:
"*" - pronounced "star"
"_" - pronounced "floor"
"^" - pronounced "hat"
"?" - pronounced "huh"
The access rules enforced by Smack are, in order:
1. Any access requested by a task labeled "*" is denied.
2. A read or execute access requested by a task labeled "^"
is permitted.
3. A read or execute access requested on an object labeled "_"
is permitted.
4. Any access requested on an object labeled "*" is permitted.
5. Any access requested by a task on an object with the same
label is permitted.
6. Any access requested that is explicitly defined in the loaded
rule set is permitted.
7. Any other access is denied.
Rules may be explicitly defined by writing subject,object,access
triples to /smack/load.
Smack rule sets can be easily defined that describe Bell&LaPadula
sensitivity, Biba integrity, and a variety of interesting
configurations. Smack rule sets can be modified on the fly to
accommodate changes in the operating environment or even the time
of day.
Some practical use cases:
Hierarchical levels. The less common of the two usual uses
for MLS systems is to define hierarchical levels, often
unclassified, confidential, secret, and so on. To set up smack
to support this, these rules could be defined:
C Unclass rx
S C rx
S Unclass rx
TS S rx
TS C rx
TS Unclass rx
A TS process can read S, C, and Unclass data, but cannot write it.
An S process can read C and Unclass. Note that specifying that
TS can read S and S can read C does not imply TS can read C, it
has to be explicitly stated.
Non-hierarchical categories. This is the more common of the
usual uses for an MLS system. Since the default rule is that a
subject cannot access an object with a different label no
access rules are required to implement compartmentalization.
A case that the Bell & LaPadula policy does not allow is demonstrated
with this Smack access rule:
A case that Bell&LaPadula does not allow that Smack does:
ESPN ABC r
ABC ESPN r
On my portable video device I have two applications, one that
shows ABC programming and the other ESPN programming. ESPN wants
to show me sport stories that show up as news, and ABC will
only provide minimal information about a sports story if ESPN
is covering it. Each side can look at the other's info, neither
can change the other. Neither can see what FOX is up to, which
is just as well all things considered.
Another case that I especially like:
SatData Guard w
Guard Publish w
A program running with the Guard label opens a UDP socket and
accepts messages sent by a program running with a SatData label.
The Guard program inspects the message to ensure it is wholesome
and if it is sends it to a program running with the Publish label.
This program then puts the information passed in an appropriate
place. Note that the Guard program cannot write to a Publish
file system object because file system semanitic require read as
well as write.
The four cases (categories, levels, mutual read, guardbox) here
are all quite real, and problems I've been asked to solve over
the years. The first two are easy to do with traditonal MLS systems
while the last two you can't without invoking privilege, at least
for a while.
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Cc: Joshua Brindle <method@manicmethod.com>
Cc: Paul Moore <paul.moore@hp.com>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: Chris Wright <chrisw@sous-sol.org>
Cc: James Morris <jmorris@namei.org>
Cc: "Ahmed S. Darwish" <darwish.07@gmail.com>
Cc: Andrew G. Morgan <morgan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-05 06:29:50 +00:00
|
|
|
|
|
|
|
return smk_curacc(sbp->smk_floor, MAY_WRITE);
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_sb_umount - Smack check for unmounting
|
|
|
|
* @mnt: file system to unmount
|
|
|
|
* @flags: unused
|
|
|
|
*
|
|
|
|
* Returns 0 if current can write the floor of the filesystem
|
|
|
|
* being unmounted, an error code otherwise.
|
|
|
|
*/
|
|
|
|
static int smack_sb_umount(struct vfsmount *mnt, int flags)
|
|
|
|
{
|
|
|
|
struct superblock_smack *sbp;
|
|
|
|
|
|
|
|
sbp = mnt->mnt_sb->s_security;
|
|
|
|
|
|
|
|
return smk_curacc(sbp->smk_floor, MAY_WRITE);
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Inode hooks
|
|
|
|
*/
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_inode_alloc_security - allocate an inode blob
|
|
|
|
* @inode - the inode in need of a blob
|
|
|
|
*
|
|
|
|
* Returns 0 if it gets a blob, -ENOMEM otherwise
|
|
|
|
*/
|
|
|
|
static int smack_inode_alloc_security(struct inode *inode)
|
|
|
|
{
|
|
|
|
inode->i_security = new_inode_smack(current->security);
|
|
|
|
if (inode->i_security == NULL)
|
|
|
|
return -ENOMEM;
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_inode_free_security - free an inode blob
|
|
|
|
* @inode - the inode with a blob
|
|
|
|
*
|
|
|
|
* Clears the blob pointer in inode
|
|
|
|
*/
|
|
|
|
static void smack_inode_free_security(struct inode *inode)
|
|
|
|
{
|
|
|
|
kfree(inode->i_security);
|
|
|
|
inode->i_security = NULL;
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_inode_init_security - copy out the smack from an inode
|
|
|
|
* @inode: the inode
|
|
|
|
* @dir: unused
|
|
|
|
* @name: where to put the attribute name
|
|
|
|
* @value: where to put the attribute value
|
|
|
|
* @len: where to put the length of the attribute
|
|
|
|
*
|
|
|
|
* Returns 0 if it all works out, -ENOMEM if there's no memory
|
|
|
|
*/
|
|
|
|
static int smack_inode_init_security(struct inode *inode, struct inode *dir,
|
|
|
|
char **name, void **value, size_t *len)
|
|
|
|
{
|
|
|
|
char *isp = smk_of_inode(inode);
|
|
|
|
|
|
|
|
if (name) {
|
|
|
|
*name = kstrdup(XATTR_SMACK_SUFFIX, GFP_KERNEL);
|
|
|
|
if (*name == NULL)
|
|
|
|
return -ENOMEM;
|
|
|
|
}
|
|
|
|
|
|
|
|
if (value) {
|
|
|
|
*value = kstrdup(isp, GFP_KERNEL);
|
|
|
|
if (*value == NULL)
|
|
|
|
return -ENOMEM;
|
|
|
|
}
|
|
|
|
|
|
|
|
if (len)
|
|
|
|
*len = strlen(isp) + 1;
|
|
|
|
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_inode_link - Smack check on link
|
|
|
|
* @old_dentry: the existing object
|
|
|
|
* @dir: unused
|
|
|
|
* @new_dentry: the new object
|
|
|
|
*
|
|
|
|
* Returns 0 if access is permitted, an error code otherwise
|
|
|
|
*/
|
|
|
|
static int smack_inode_link(struct dentry *old_dentry, struct inode *dir,
|
|
|
|
struct dentry *new_dentry)
|
|
|
|
{
|
|
|
|
int rc;
|
|
|
|
char *isp;
|
|
|
|
|
|
|
|
isp = smk_of_inode(old_dentry->d_inode);
|
|
|
|
rc = smk_curacc(isp, MAY_WRITE);
|
|
|
|
|
|
|
|
if (rc == 0 && new_dentry->d_inode != NULL) {
|
|
|
|
isp = smk_of_inode(new_dentry->d_inode);
|
|
|
|
rc = smk_curacc(isp, MAY_WRITE);
|
|
|
|
}
|
|
|
|
|
|
|
|
return rc;
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_inode_unlink - Smack check on inode deletion
|
|
|
|
* @dir: containing directory object
|
|
|
|
* @dentry: file to unlink
|
|
|
|
*
|
|
|
|
* Returns 0 if current can write the containing directory
|
|
|
|
* and the object, error code otherwise
|
|
|
|
*/
|
|
|
|
static int smack_inode_unlink(struct inode *dir, struct dentry *dentry)
|
|
|
|
{
|
|
|
|
struct inode *ip = dentry->d_inode;
|
|
|
|
int rc;
|
|
|
|
|
|
|
|
/*
|
|
|
|
* You need write access to the thing you're unlinking
|
|
|
|
*/
|
|
|
|
rc = smk_curacc(smk_of_inode(ip), MAY_WRITE);
|
|
|
|
if (rc == 0)
|
|
|
|
/*
|
|
|
|
* You also need write access to the containing directory
|
|
|
|
*/
|
|
|
|
rc = smk_curacc(smk_of_inode(dir), MAY_WRITE);
|
|
|
|
|
|
|
|
return rc;
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_inode_rmdir - Smack check on directory deletion
|
|
|
|
* @dir: containing directory object
|
|
|
|
* @dentry: directory to unlink
|
|
|
|
*
|
|
|
|
* Returns 0 if current can write the containing directory
|
|
|
|
* and the directory, error code otherwise
|
|
|
|
*/
|
|
|
|
static int smack_inode_rmdir(struct inode *dir, struct dentry *dentry)
|
|
|
|
{
|
|
|
|
int rc;
|
|
|
|
|
|
|
|
/*
|
|
|
|
* You need write access to the thing you're removing
|
|
|
|
*/
|
|
|
|
rc = smk_curacc(smk_of_inode(dentry->d_inode), MAY_WRITE);
|
|
|
|
if (rc == 0)
|
|
|
|
/*
|
|
|
|
* You also need write access to the containing directory
|
|
|
|
*/
|
|
|
|
rc = smk_curacc(smk_of_inode(dir), MAY_WRITE);
|
|
|
|
|
|
|
|
return rc;
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_inode_rename - Smack check on rename
|
|
|
|
* @old_inode: the old directory
|
|
|
|
* @old_dentry: unused
|
|
|
|
* @new_inode: the new directory
|
|
|
|
* @new_dentry: unused
|
|
|
|
*
|
|
|
|
* Read and write access is required on both the old and
|
|
|
|
* new directories.
|
|
|
|
*
|
|
|
|
* Returns 0 if access is permitted, an error code otherwise
|
|
|
|
*/
|
|
|
|
static int smack_inode_rename(struct inode *old_inode,
|
|
|
|
struct dentry *old_dentry,
|
|
|
|
struct inode *new_inode,
|
|
|
|
struct dentry *new_dentry)
|
|
|
|
{
|
|
|
|
int rc;
|
|
|
|
char *isp;
|
|
|
|
|
|
|
|
isp = smk_of_inode(old_dentry->d_inode);
|
|
|
|
rc = smk_curacc(isp, MAY_READWRITE);
|
|
|
|
|
|
|
|
if (rc == 0 && new_dentry->d_inode != NULL) {
|
|
|
|
isp = smk_of_inode(new_dentry->d_inode);
|
|
|
|
rc = smk_curacc(isp, MAY_READWRITE);
|
|
|
|
}
|
|
|
|
|
|
|
|
return rc;
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_inode_permission - Smack version of permission()
|
|
|
|
* @inode: the inode in question
|
|
|
|
* @mask: the access requested
|
|
|
|
* @nd: unused
|
|
|
|
*
|
|
|
|
* This is the important Smack hook.
|
|
|
|
*
|
|
|
|
* Returns 0 if access is permitted, -EACCES otherwise
|
|
|
|
*/
|
|
|
|
static int smack_inode_permission(struct inode *inode, int mask,
|
|
|
|
struct nameidata *nd)
|
|
|
|
{
|
|
|
|
/*
|
|
|
|
* No permission to check. Existence test. Yup, it's there.
|
|
|
|
*/
|
|
|
|
if (mask == 0)
|
|
|
|
return 0;
|
|
|
|
|
|
|
|
return smk_curacc(smk_of_inode(inode), mask);
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_inode_setattr - Smack check for setting attributes
|
|
|
|
* @dentry: the object
|
|
|
|
* @iattr: for the force flag
|
|
|
|
*
|
|
|
|
* Returns 0 if access is permitted, an error code otherwise
|
|
|
|
*/
|
|
|
|
static int smack_inode_setattr(struct dentry *dentry, struct iattr *iattr)
|
|
|
|
{
|
|
|
|
/*
|
|
|
|
* Need to allow for clearing the setuid bit.
|
|
|
|
*/
|
|
|
|
if (iattr->ia_valid & ATTR_FORCE)
|
|
|
|
return 0;
|
|
|
|
|
|
|
|
return smk_curacc(smk_of_inode(dentry->d_inode), MAY_WRITE);
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_inode_getattr - Smack check for getting attributes
|
|
|
|
* @mnt: unused
|
|
|
|
* @dentry: the object
|
|
|
|
*
|
|
|
|
* Returns 0 if access is permitted, an error code otherwise
|
|
|
|
*/
|
|
|
|
static int smack_inode_getattr(struct vfsmount *mnt, struct dentry *dentry)
|
|
|
|
{
|
|
|
|
return smk_curacc(smk_of_inode(dentry->d_inode), MAY_READ);
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_inode_setxattr - Smack check for setting xattrs
|
|
|
|
* @dentry: the object
|
|
|
|
* @name: name of the attribute
|
|
|
|
* @value: unused
|
|
|
|
* @size: unused
|
|
|
|
* @flags: unused
|
|
|
|
*
|
|
|
|
* This protects the Smack attribute explicitly.
|
|
|
|
*
|
|
|
|
* Returns 0 if access is permitted, an error code otherwise
|
|
|
|
*/
|
|
|
|
static int smack_inode_setxattr(struct dentry *dentry, char *name,
|
|
|
|
void *value, size_t size, int flags)
|
|
|
|
{
|
2008-02-23 23:24:04 +00:00
|
|
|
int rc = 0;
|
Smack: Simplified Mandatory Access Control Kernel
Smack is the Simplified Mandatory Access Control Kernel.
Smack implements mandatory access control (MAC) using labels
attached to tasks and data containers, including files, SVIPC,
and other tasks. Smack is a kernel based scheme that requires
an absolute minimum of application support and a very small
amount of configuration data.
Smack uses extended attributes and
provides a set of general mount options, borrowing technics used
elsewhere. Smack uses netlabel for CIPSO labeling. Smack provides
a pseudo-filesystem smackfs that is used for manipulation of
system Smack attributes.
The patch, patches for ls and sshd, a README, a startup script,
and x86 binaries for ls and sshd are also available on
http://www.schaufler-ca.com
Development has been done using Fedora Core 7 in a virtual machine
environment and on an old Sony laptop.
Smack provides mandatory access controls based on the label attached
to a task and the label attached to the object it is attempting to
access. Smack labels are deliberately short (1-23 characters) text
strings. Single character labels using special characters are reserved
for system use. The only operation applied to Smack labels is equality
comparison. No wildcards or expressions, regular or otherwise, are
used. Smack labels are composed of printable characters and may not
include "/".
A file always gets the Smack label of the task that created it.
Smack defines and uses these labels:
"*" - pronounced "star"
"_" - pronounced "floor"
"^" - pronounced "hat"
"?" - pronounced "huh"
The access rules enforced by Smack are, in order:
1. Any access requested by a task labeled "*" is denied.
2. A read or execute access requested by a task labeled "^"
is permitted.
3. A read or execute access requested on an object labeled "_"
is permitted.
4. Any access requested on an object labeled "*" is permitted.
5. Any access requested by a task on an object with the same
label is permitted.
6. Any access requested that is explicitly defined in the loaded
rule set is permitted.
7. Any other access is denied.
Rules may be explicitly defined by writing subject,object,access
triples to /smack/load.
Smack rule sets can be easily defined that describe Bell&LaPadula
sensitivity, Biba integrity, and a variety of interesting
configurations. Smack rule sets can be modified on the fly to
accommodate changes in the operating environment or even the time
of day.
Some practical use cases:
Hierarchical levels. The less common of the two usual uses
for MLS systems is to define hierarchical levels, often
unclassified, confidential, secret, and so on. To set up smack
to support this, these rules could be defined:
C Unclass rx
S C rx
S Unclass rx
TS S rx
TS C rx
TS Unclass rx
A TS process can read S, C, and Unclass data, but cannot write it.
An S process can read C and Unclass. Note that specifying that
TS can read S and S can read C does not imply TS can read C, it
has to be explicitly stated.
Non-hierarchical categories. This is the more common of the
usual uses for an MLS system. Since the default rule is that a
subject cannot access an object with a different label no
access rules are required to implement compartmentalization.
A case that the Bell & LaPadula policy does not allow is demonstrated
with this Smack access rule:
A case that Bell&LaPadula does not allow that Smack does:
ESPN ABC r
ABC ESPN r
On my portable video device I have two applications, one that
shows ABC programming and the other ESPN programming. ESPN wants
to show me sport stories that show up as news, and ABC will
only provide minimal information about a sports story if ESPN
is covering it. Each side can look at the other's info, neither
can change the other. Neither can see what FOX is up to, which
is just as well all things considered.
Another case that I especially like:
SatData Guard w
Guard Publish w
A program running with the Guard label opens a UDP socket and
accepts messages sent by a program running with a SatData label.
The Guard program inspects the message to ensure it is wholesome
and if it is sends it to a program running with the Publish label.
This program then puts the information passed in an appropriate
place. Note that the Guard program cannot write to a Publish
file system object because file system semanitic require read as
well as write.
The four cases (categories, levels, mutual read, guardbox) here
are all quite real, and problems I've been asked to solve over
the years. The first two are easy to do with traditonal MLS systems
while the last two you can't without invoking privilege, at least
for a while.
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Cc: Joshua Brindle <method@manicmethod.com>
Cc: Paul Moore <paul.moore@hp.com>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: Chris Wright <chrisw@sous-sol.org>
Cc: James Morris <jmorris@namei.org>
Cc: "Ahmed S. Darwish" <darwish.07@gmail.com>
Cc: Andrew G. Morgan <morgan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-05 06:29:50 +00:00
|
|
|
|
2008-02-23 23:24:04 +00:00
|
|
|
if (strcmp(name, XATTR_NAME_SMACK) == 0 ||
|
|
|
|
strcmp(name, XATTR_NAME_SMACKIPIN) == 0 ||
|
|
|
|
strcmp(name, XATTR_NAME_SMACKIPOUT) == 0) {
|
|
|
|
if (!capable(CAP_MAC_ADMIN))
|
|
|
|
rc = -EPERM;
|
|
|
|
} else
|
|
|
|
rc = cap_inode_setxattr(dentry, name, value, size, flags);
|
|
|
|
|
|
|
|
if (rc == 0)
|
|
|
|
rc = smk_curacc(smk_of_inode(dentry->d_inode), MAY_WRITE);
|
|
|
|
|
|
|
|
return rc;
|
Smack: Simplified Mandatory Access Control Kernel
Smack is the Simplified Mandatory Access Control Kernel.
Smack implements mandatory access control (MAC) using labels
attached to tasks and data containers, including files, SVIPC,
and other tasks. Smack is a kernel based scheme that requires
an absolute minimum of application support and a very small
amount of configuration data.
Smack uses extended attributes and
provides a set of general mount options, borrowing technics used
elsewhere. Smack uses netlabel for CIPSO labeling. Smack provides
a pseudo-filesystem smackfs that is used for manipulation of
system Smack attributes.
The patch, patches for ls and sshd, a README, a startup script,
and x86 binaries for ls and sshd are also available on
http://www.schaufler-ca.com
Development has been done using Fedora Core 7 in a virtual machine
environment and on an old Sony laptop.
Smack provides mandatory access controls based on the label attached
to a task and the label attached to the object it is attempting to
access. Smack labels are deliberately short (1-23 characters) text
strings. Single character labels using special characters are reserved
for system use. The only operation applied to Smack labels is equality
comparison. No wildcards or expressions, regular or otherwise, are
used. Smack labels are composed of printable characters and may not
include "/".
A file always gets the Smack label of the task that created it.
Smack defines and uses these labels:
"*" - pronounced "star"
"_" - pronounced "floor"
"^" - pronounced "hat"
"?" - pronounced "huh"
The access rules enforced by Smack are, in order:
1. Any access requested by a task labeled "*" is denied.
2. A read or execute access requested by a task labeled "^"
is permitted.
3. A read or execute access requested on an object labeled "_"
is permitted.
4. Any access requested on an object labeled "*" is permitted.
5. Any access requested by a task on an object with the same
label is permitted.
6. Any access requested that is explicitly defined in the loaded
rule set is permitted.
7. Any other access is denied.
Rules may be explicitly defined by writing subject,object,access
triples to /smack/load.
Smack rule sets can be easily defined that describe Bell&LaPadula
sensitivity, Biba integrity, and a variety of interesting
configurations. Smack rule sets can be modified on the fly to
accommodate changes in the operating environment or even the time
of day.
Some practical use cases:
Hierarchical levels. The less common of the two usual uses
for MLS systems is to define hierarchical levels, often
unclassified, confidential, secret, and so on. To set up smack
to support this, these rules could be defined:
C Unclass rx
S C rx
S Unclass rx
TS S rx
TS C rx
TS Unclass rx
A TS process can read S, C, and Unclass data, but cannot write it.
An S process can read C and Unclass. Note that specifying that
TS can read S and S can read C does not imply TS can read C, it
has to be explicitly stated.
Non-hierarchical categories. This is the more common of the
usual uses for an MLS system. Since the default rule is that a
subject cannot access an object with a different label no
access rules are required to implement compartmentalization.
A case that the Bell & LaPadula policy does not allow is demonstrated
with this Smack access rule:
A case that Bell&LaPadula does not allow that Smack does:
ESPN ABC r
ABC ESPN r
On my portable video device I have two applications, one that
shows ABC programming and the other ESPN programming. ESPN wants
to show me sport stories that show up as news, and ABC will
only provide minimal information about a sports story if ESPN
is covering it. Each side can look at the other's info, neither
can change the other. Neither can see what FOX is up to, which
is just as well all things considered.
Another case that I especially like:
SatData Guard w
Guard Publish w
A program running with the Guard label opens a UDP socket and
accepts messages sent by a program running with a SatData label.
The Guard program inspects the message to ensure it is wholesome
and if it is sends it to a program running with the Publish label.
This program then puts the information passed in an appropriate
place. Note that the Guard program cannot write to a Publish
file system object because file system semanitic require read as
well as write.
The four cases (categories, levels, mutual read, guardbox) here
are all quite real, and problems I've been asked to solve over
the years. The first two are easy to do with traditonal MLS systems
while the last two you can't without invoking privilege, at least
for a while.
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Cc: Joshua Brindle <method@manicmethod.com>
Cc: Paul Moore <paul.moore@hp.com>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: Chris Wright <chrisw@sous-sol.org>
Cc: James Morris <jmorris@namei.org>
Cc: "Ahmed S. Darwish" <darwish.07@gmail.com>
Cc: Andrew G. Morgan <morgan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-05 06:29:50 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_inode_post_setxattr - Apply the Smack update approved above
|
|
|
|
* @dentry: object
|
|
|
|
* @name: attribute name
|
|
|
|
* @value: attribute value
|
|
|
|
* @size: attribute size
|
|
|
|
* @flags: unused
|
|
|
|
*
|
|
|
|
* Set the pointer in the inode blob to the entry found
|
|
|
|
* in the master label list.
|
|
|
|
*/
|
|
|
|
static void smack_inode_post_setxattr(struct dentry *dentry, char *name,
|
|
|
|
void *value, size_t size, int flags)
|
|
|
|
{
|
|
|
|
struct inode_smack *isp;
|
|
|
|
char *nsp;
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Not SMACK
|
|
|
|
*/
|
|
|
|
if (strcmp(name, XATTR_NAME_SMACK))
|
|
|
|
return;
|
|
|
|
|
|
|
|
if (size >= SMK_LABELLEN)
|
|
|
|
return;
|
|
|
|
|
|
|
|
isp = dentry->d_inode->i_security;
|
|
|
|
|
|
|
|
/*
|
|
|
|
* No locking is done here. This is a pointer
|
|
|
|
* assignment.
|
|
|
|
*/
|
|
|
|
nsp = smk_import(value, size);
|
|
|
|
if (nsp != NULL)
|
|
|
|
isp->smk_inode = nsp;
|
|
|
|
else
|
|
|
|
isp->smk_inode = smack_known_invalid.smk_known;
|
|
|
|
|
|
|
|
return;
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* smack_inode_getxattr - Smack check on getxattr
|
|
|
|
* @dentry: the object
|
|
|
|
* @name: unused
|
|
|
|
*
|
|
|
|
* Returns 0 if access is permitted, an error code otherwise
|
|
|
|
*/
|
|
|
|
static int smack_inode_getxattr(struct dentry *dentry, char *name)
|
|
|
|
{
|
|
|
|
return smk_curacc(smk_of_inode(dentry->d_inode), MAY_READ);
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* smack_inode_removexattr - Smack check on removexattr
|
|
|
|
* @dentry: the object
|
|
|
|
* @name: name of the attribute
|
|
|
|
*
|
|
|
|
* Removing the Smack attribute requires CAP_MAC_ADMIN
|
|
|
|
*
|
|
|
|
* Returns 0 if access is permitted, an error code otherwise
|
|
|
|
*/
|
|
|
|
static int smack_inode_removexattr(struct dentry *dentry, char *name)
|
|
|
|
{
|
2008-02-23 23:24:04 +00:00
|
|
|
int rc = 0;
|
Smack: Simplified Mandatory Access Control Kernel
Smack is the Simplified Mandatory Access Control Kernel.
Smack implements mandatory access control (MAC) using labels
attached to tasks and data containers, including files, SVIPC,
and other tasks. Smack is a kernel based scheme that requires
an absolute minimum of application support and a very small
amount of configuration data.
Smack uses extended attributes and
provides a set of general mount options, borrowing technics used
elsewhere. Smack uses netlabel for CIPSO labeling. Smack provides
a pseudo-filesystem smackfs that is used for manipulation of
system Smack attributes.
The patch, patches for ls and sshd, a README, a startup script,
and x86 binaries for ls and sshd are also available on
http://www.schaufler-ca.com
Development has been done using Fedora Core 7 in a virtual machine
environment and on an old Sony laptop.
Smack provides mandatory access controls based on the label attached
to a task and the label attached to the object it is attempting to
access. Smack labels are deliberately short (1-23 characters) text
strings. Single character labels using special characters are reserved
for system use. The only operation applied to Smack labels is equality
comparison. No wildcards or expressions, regular or otherwise, are
used. Smack labels are composed of printable characters and may not
include "/".
A file always gets the Smack label of the task that created it.
Smack defines and uses these labels:
"*" - pronounced "star"
"_" - pronounced "floor"
"^" - pronounced "hat"
"?" - pronounced "huh"
The access rules enforced by Smack are, in order:
1. Any access requested by a task labeled "*" is denied.
2. A read or execute access requested by a task labeled "^"
is permitted.
3. A read or execute access requested on an object labeled "_"
is permitted.
4. Any access requested on an object labeled "*" is permitted.
5. Any access requested by a task on an object with the same
label is permitted.
6. Any access requested that is explicitly defined in the loaded
rule set is permitted.
7. Any other access is denied.
Rules may be explicitly defined by writing subject,object,access
triples to /smack/load.
Smack rule sets can be easily defined that describe Bell&LaPadula
sensitivity, Biba integrity, and a variety of interesting
configurations. Smack rule sets can be modified on the fly to
accommodate changes in the operating environment or even the time
of day.
Some practical use cases:
Hierarchical levels. The less common of the two usual uses
for MLS systems is to define hierarchical levels, often
unclassified, confidential, secret, and so on. To set up smack
to support this, these rules could be defined:
C Unclass rx
S C rx
S Unclass rx
TS S rx
TS C rx
TS Unclass rx
A TS process can read S, C, and Unclass data, but cannot write it.
An S process can read C and Unclass. Note that specifying that
TS can read S and S can read C does not imply TS can read C, it
has to be explicitly stated.
Non-hierarchical categories. This is the more common of the
usual uses for an MLS system. Since the default rule is that a
subject cannot access an object with a different label no
access rules are required to implement compartmentalization.
A case that the Bell & LaPadula policy does not allow is demonstrated
with this Smack access rule:
A case that Bell&LaPadula does not allow that Smack does:
ESPN ABC r
ABC ESPN r
On my portable video device I have two applications, one that
shows ABC programming and the other ESPN programming. ESPN wants
to show me sport stories that show up as news, and ABC will
only provide minimal information about a sports story if ESPN
is covering it. Each side can look at the other's info, neither
can change the other. Neither can see what FOX is up to, which
is just as well all things considered.
Another case that I especially like:
SatData Guard w
Guard Publish w
A program running with the Guard label opens a UDP socket and
accepts messages sent by a program running with a SatData label.
The Guard program inspects the message to ensure it is wholesome
and if it is sends it to a program running with the Publish label.
This program then puts the information passed in an appropriate
place. Note that the Guard program cannot write to a Publish
file system object because file system semanitic require read as
well as write.
The four cases (categories, levels, mutual read, guardbox) here
are all quite real, and problems I've been asked to solve over
the years. The first two are easy to do with traditonal MLS systems
while the last two you can't without invoking privilege, at least
for a while.
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Cc: Joshua Brindle <method@manicmethod.com>
Cc: Paul Moore <paul.moore@hp.com>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: Chris Wright <chrisw@sous-sol.org>
Cc: James Morris <jmorris@namei.org>
Cc: "Ahmed S. Darwish" <darwish.07@gmail.com>
Cc: Andrew G. Morgan <morgan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-05 06:29:50 +00:00
|
|
|
|
2008-02-23 23:24:04 +00:00
|
|
|
if (strcmp(name, XATTR_NAME_SMACK) == 0 ||
|
|
|
|
strcmp(name, XATTR_NAME_SMACKIPIN) == 0 ||
|
|
|
|
strcmp(name, XATTR_NAME_SMACKIPOUT) == 0) {
|
|
|
|
if (!capable(CAP_MAC_ADMIN))
|
|
|
|
rc = -EPERM;
|
|
|
|
} else
|
|
|
|
rc = cap_inode_removexattr(dentry, name);
|
|
|
|
|
|
|
|
if (rc == 0)
|
|
|
|
rc = smk_curacc(smk_of_inode(dentry->d_inode), MAY_WRITE);
|
|
|
|
|
|
|
|
return rc;
|
Smack: Simplified Mandatory Access Control Kernel
Smack is the Simplified Mandatory Access Control Kernel.
Smack implements mandatory access control (MAC) using labels
attached to tasks and data containers, including files, SVIPC,
and other tasks. Smack is a kernel based scheme that requires
an absolute minimum of application support and a very small
amount of configuration data.
Smack uses extended attributes and
provides a set of general mount options, borrowing technics used
elsewhere. Smack uses netlabel for CIPSO labeling. Smack provides
a pseudo-filesystem smackfs that is used for manipulation of
system Smack attributes.
The patch, patches for ls and sshd, a README, a startup script,
and x86 binaries for ls and sshd are also available on
http://www.schaufler-ca.com
Development has been done using Fedora Core 7 in a virtual machine
environment and on an old Sony laptop.
Smack provides mandatory access controls based on the label attached
to a task and the label attached to the object it is attempting to
access. Smack labels are deliberately short (1-23 characters) text
strings. Single character labels using special characters are reserved
for system use. The only operation applied to Smack labels is equality
comparison. No wildcards or expressions, regular or otherwise, are
used. Smack labels are composed of printable characters and may not
include "/".
A file always gets the Smack label of the task that created it.
Smack defines and uses these labels:
"*" - pronounced "star"
"_" - pronounced "floor"
"^" - pronounced "hat"
"?" - pronounced "huh"
The access rules enforced by Smack are, in order:
1. Any access requested by a task labeled "*" is denied.
2. A read or execute access requested by a task labeled "^"
is permitted.
3. A read or execute access requested on an object labeled "_"
is permitted.
4. Any access requested on an object labeled "*" is permitted.
5. Any access requested by a task on an object with the same
label is permitted.
6. Any access requested that is explicitly defined in the loaded
rule set is permitted.
7. Any other access is denied.
Rules may be explicitly defined by writing subject,object,access
triples to /smack/load.
Smack rule sets can be easily defined that describe Bell&LaPadula
sensitivity, Biba integrity, and a variety of interesting
configurations. Smack rule sets can be modified on the fly to
accommodate changes in the operating environment or even the time
of day.
Some practical use cases:
Hierarchical levels. The less common of the two usual uses
for MLS systems is to define hierarchical levels, often
unclassified, confidential, secret, and so on. To set up smack
to support this, these rules could be defined:
C Unclass rx
S C rx
S Unclass rx
TS S rx
TS C rx
TS Unclass rx
A TS process can read S, C, and Unclass data, but cannot write it.
An S process can read C and Unclass. Note that specifying that
TS can read S and S can read C does not imply TS can read C, it
has to be explicitly stated.
Non-hierarchical categories. This is the more common of the
usual uses for an MLS system. Since the default rule is that a
subject cannot access an object with a different label no
access rules are required to implement compartmentalization.
A case that the Bell & LaPadula policy does not allow is demonstrated
with this Smack access rule:
A case that Bell&LaPadula does not allow that Smack does:
ESPN ABC r
ABC ESPN r
On my portable video device I have two applications, one that
shows ABC programming and the other ESPN programming. ESPN wants
to show me sport stories that show up as news, and ABC will
only provide minimal information about a sports story if ESPN
is covering it. Each side can look at the other's info, neither
can change the other. Neither can see what FOX is up to, which
is just as well all things considered.
Another case that I especially like:
SatData Guard w
Guard Publish w
A program running with the Guard label opens a UDP socket and
accepts messages sent by a program running with a SatData label.
The Guard program inspects the message to ensure it is wholesome
and if it is sends it to a program running with the Publish label.
This program then puts the information passed in an appropriate
place. Note that the Guard program cannot write to a Publish
file system object because file system semanitic require read as
well as write.
The four cases (categories, levels, mutual read, guardbox) here
are all quite real, and problems I've been asked to solve over
the years. The first two are easy to do with traditonal MLS systems
while the last two you can't without invoking privilege, at least
for a while.
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Cc: Joshua Brindle <method@manicmethod.com>
Cc: Paul Moore <paul.moore@hp.com>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: Chris Wright <chrisw@sous-sol.org>
Cc: James Morris <jmorris@namei.org>
Cc: "Ahmed S. Darwish" <darwish.07@gmail.com>
Cc: Andrew G. Morgan <morgan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-05 06:29:50 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_inode_getsecurity - get smack xattrs
|
|
|
|
* @inode: the object
|
|
|
|
* @name: attribute name
|
|
|
|
* @buffer: where to put the result
|
|
|
|
* @size: size of the buffer
|
|
|
|
* @err: unused
|
|
|
|
*
|
|
|
|
* Returns the size of the attribute or an error code
|
|
|
|
*/
|
|
|
|
static int smack_inode_getsecurity(const struct inode *inode,
|
|
|
|
const char *name, void **buffer,
|
|
|
|
bool alloc)
|
|
|
|
{
|
|
|
|
struct socket_smack *ssp;
|
|
|
|
struct socket *sock;
|
|
|
|
struct super_block *sbp;
|
|
|
|
struct inode *ip = (struct inode *)inode;
|
|
|
|
char *isp;
|
|
|
|
int ilen;
|
|
|
|
int rc = 0;
|
|
|
|
|
|
|
|
if (strcmp(name, XATTR_SMACK_SUFFIX) == 0) {
|
|
|
|
isp = smk_of_inode(inode);
|
|
|
|
ilen = strlen(isp) + 1;
|
|
|
|
*buffer = isp;
|
|
|
|
return ilen;
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* The rest of the Smack xattrs are only on sockets.
|
|
|
|
*/
|
|
|
|
sbp = ip->i_sb;
|
|
|
|
if (sbp->s_magic != SOCKFS_MAGIC)
|
|
|
|
return -EOPNOTSUPP;
|
|
|
|
|
|
|
|
sock = SOCKET_I(ip);
|
2008-02-13 23:03:34 +00:00
|
|
|
if (sock == NULL || sock->sk == NULL)
|
Smack: Simplified Mandatory Access Control Kernel
Smack is the Simplified Mandatory Access Control Kernel.
Smack implements mandatory access control (MAC) using labels
attached to tasks and data containers, including files, SVIPC,
and other tasks. Smack is a kernel based scheme that requires
an absolute minimum of application support and a very small
amount of configuration data.
Smack uses extended attributes and
provides a set of general mount options, borrowing technics used
elsewhere. Smack uses netlabel for CIPSO labeling. Smack provides
a pseudo-filesystem smackfs that is used for manipulation of
system Smack attributes.
The patch, patches for ls and sshd, a README, a startup script,
and x86 binaries for ls and sshd are also available on
http://www.schaufler-ca.com
Development has been done using Fedora Core 7 in a virtual machine
environment and on an old Sony laptop.
Smack provides mandatory access controls based on the label attached
to a task and the label attached to the object it is attempting to
access. Smack labels are deliberately short (1-23 characters) text
strings. Single character labels using special characters are reserved
for system use. The only operation applied to Smack labels is equality
comparison. No wildcards or expressions, regular or otherwise, are
used. Smack labels are composed of printable characters and may not
include "/".
A file always gets the Smack label of the task that created it.
Smack defines and uses these labels:
"*" - pronounced "star"
"_" - pronounced "floor"
"^" - pronounced "hat"
"?" - pronounced "huh"
The access rules enforced by Smack are, in order:
1. Any access requested by a task labeled "*" is denied.
2. A read or execute access requested by a task labeled "^"
is permitted.
3. A read or execute access requested on an object labeled "_"
is permitted.
4. Any access requested on an object labeled "*" is permitted.
5. Any access requested by a task on an object with the same
label is permitted.
6. Any access requested that is explicitly defined in the loaded
rule set is permitted.
7. Any other access is denied.
Rules may be explicitly defined by writing subject,object,access
triples to /smack/load.
Smack rule sets can be easily defined that describe Bell&LaPadula
sensitivity, Biba integrity, and a variety of interesting
configurations. Smack rule sets can be modified on the fly to
accommodate changes in the operating environment or even the time
of day.
Some practical use cases:
Hierarchical levels. The less common of the two usual uses
for MLS systems is to define hierarchical levels, often
unclassified, confidential, secret, and so on. To set up smack
to support this, these rules could be defined:
C Unclass rx
S C rx
S Unclass rx
TS S rx
TS C rx
TS Unclass rx
A TS process can read S, C, and Unclass data, but cannot write it.
An S process can read C and Unclass. Note that specifying that
TS can read S and S can read C does not imply TS can read C, it
has to be explicitly stated.
Non-hierarchical categories. This is the more common of the
usual uses for an MLS system. Since the default rule is that a
subject cannot access an object with a different label no
access rules are required to implement compartmentalization.
A case that the Bell & LaPadula policy does not allow is demonstrated
with this Smack access rule:
A case that Bell&LaPadula does not allow that Smack does:
ESPN ABC r
ABC ESPN r
On my portable video device I have two applications, one that
shows ABC programming and the other ESPN programming. ESPN wants
to show me sport stories that show up as news, and ABC will
only provide minimal information about a sports story if ESPN
is covering it. Each side can look at the other's info, neither
can change the other. Neither can see what FOX is up to, which
is just as well all things considered.
Another case that I especially like:
SatData Guard w
Guard Publish w
A program running with the Guard label opens a UDP socket and
accepts messages sent by a program running with a SatData label.
The Guard program inspects the message to ensure it is wholesome
and if it is sends it to a program running with the Publish label.
This program then puts the information passed in an appropriate
place. Note that the Guard program cannot write to a Publish
file system object because file system semanitic require read as
well as write.
The four cases (categories, levels, mutual read, guardbox) here
are all quite real, and problems I've been asked to solve over
the years. The first two are easy to do with traditonal MLS systems
while the last two you can't without invoking privilege, at least
for a while.
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Cc: Joshua Brindle <method@manicmethod.com>
Cc: Paul Moore <paul.moore@hp.com>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: Chris Wright <chrisw@sous-sol.org>
Cc: James Morris <jmorris@namei.org>
Cc: "Ahmed S. Darwish" <darwish.07@gmail.com>
Cc: Andrew G. Morgan <morgan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-05 06:29:50 +00:00
|
|
|
return -EOPNOTSUPP;
|
|
|
|
|
|
|
|
ssp = sock->sk->sk_security;
|
|
|
|
|
|
|
|
if (strcmp(name, XATTR_SMACK_IPIN) == 0)
|
|
|
|
isp = ssp->smk_in;
|
|
|
|
else if (strcmp(name, XATTR_SMACK_IPOUT) == 0)
|
|
|
|
isp = ssp->smk_out;
|
|
|
|
else
|
|
|
|
return -EOPNOTSUPP;
|
|
|
|
|
|
|
|
ilen = strlen(isp) + 1;
|
|
|
|
if (rc == 0) {
|
|
|
|
*buffer = isp;
|
|
|
|
rc = ilen;
|
|
|
|
}
|
|
|
|
|
|
|
|
return rc;
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_inode_listsecurity - list the Smack attributes
|
|
|
|
* @inode: the object
|
|
|
|
* @buffer: where they go
|
|
|
|
* @buffer_size: size of buffer
|
|
|
|
*
|
|
|
|
* Returns 0 on success, -EINVAL otherwise
|
|
|
|
*/
|
|
|
|
static int smack_inode_listsecurity(struct inode *inode, char *buffer,
|
|
|
|
size_t buffer_size)
|
|
|
|
{
|
|
|
|
int len = strlen(XATTR_NAME_SMACK);
|
|
|
|
|
|
|
|
if (buffer != NULL && len <= buffer_size) {
|
|
|
|
memcpy(buffer, XATTR_NAME_SMACK, len);
|
|
|
|
return len;
|
|
|
|
}
|
|
|
|
return -EINVAL;
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* File Hooks
|
|
|
|
*/
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_file_permission - Smack check on file operations
|
|
|
|
* @file: unused
|
|
|
|
* @mask: unused
|
|
|
|
*
|
|
|
|
* Returns 0
|
|
|
|
*
|
|
|
|
* Should access checks be done on each read or write?
|
|
|
|
* UNICOS and SELinux say yes.
|
|
|
|
* Trusted Solaris, Trusted Irix, and just about everyone else says no.
|
|
|
|
*
|
|
|
|
* I'll say no for now. Smack does not do the frequent
|
|
|
|
* label changing that SELinux does.
|
|
|
|
*/
|
|
|
|
static int smack_file_permission(struct file *file, int mask)
|
|
|
|
{
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_file_alloc_security - assign a file security blob
|
|
|
|
* @file: the object
|
|
|
|
*
|
|
|
|
* The security blob for a file is a pointer to the master
|
|
|
|
* label list, so no allocation is done.
|
|
|
|
*
|
|
|
|
* Returns 0
|
|
|
|
*/
|
|
|
|
static int smack_file_alloc_security(struct file *file)
|
|
|
|
{
|
|
|
|
file->f_security = current->security;
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_file_free_security - clear a file security blob
|
|
|
|
* @file: the object
|
|
|
|
*
|
|
|
|
* The security blob for a file is a pointer to the master
|
|
|
|
* label list, so no memory is freed.
|
|
|
|
*/
|
|
|
|
static void smack_file_free_security(struct file *file)
|
|
|
|
{
|
|
|
|
file->f_security = NULL;
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_file_ioctl - Smack check on ioctls
|
|
|
|
* @file: the object
|
|
|
|
* @cmd: what to do
|
|
|
|
* @arg: unused
|
|
|
|
*
|
|
|
|
* Relies heavily on the correct use of the ioctl command conventions.
|
|
|
|
*
|
|
|
|
* Returns 0 if allowed, error code otherwise
|
|
|
|
*/
|
|
|
|
static int smack_file_ioctl(struct file *file, unsigned int cmd,
|
|
|
|
unsigned long arg)
|
|
|
|
{
|
|
|
|
int rc = 0;
|
|
|
|
|
|
|
|
if (_IOC_DIR(cmd) & _IOC_WRITE)
|
|
|
|
rc = smk_curacc(file->f_security, MAY_WRITE);
|
|
|
|
|
|
|
|
if (rc == 0 && (_IOC_DIR(cmd) & _IOC_READ))
|
|
|
|
rc = smk_curacc(file->f_security, MAY_READ);
|
|
|
|
|
|
|
|
return rc;
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_file_lock - Smack check on file locking
|
|
|
|
* @file: the object
|
|
|
|
* @cmd unused
|
|
|
|
*
|
|
|
|
* Returns 0 if current has write access, error code otherwise
|
|
|
|
*/
|
|
|
|
static int smack_file_lock(struct file *file, unsigned int cmd)
|
|
|
|
{
|
|
|
|
return smk_curacc(file->f_security, MAY_WRITE);
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_file_fcntl - Smack check on fcntl
|
|
|
|
* @file: the object
|
|
|
|
* @cmd: what action to check
|
|
|
|
* @arg: unused
|
|
|
|
*
|
|
|
|
* Returns 0 if current has access, error code otherwise
|
|
|
|
*/
|
|
|
|
static int smack_file_fcntl(struct file *file, unsigned int cmd,
|
|
|
|
unsigned long arg)
|
|
|
|
{
|
|
|
|
int rc;
|
|
|
|
|
|
|
|
switch (cmd) {
|
|
|
|
case F_DUPFD:
|
|
|
|
case F_GETFD:
|
|
|
|
case F_GETFL:
|
|
|
|
case F_GETLK:
|
|
|
|
case F_GETOWN:
|
|
|
|
case F_GETSIG:
|
|
|
|
rc = smk_curacc(file->f_security, MAY_READ);
|
|
|
|
break;
|
|
|
|
case F_SETFD:
|
|
|
|
case F_SETFL:
|
|
|
|
case F_SETLK:
|
|
|
|
case F_SETLKW:
|
|
|
|
case F_SETOWN:
|
|
|
|
case F_SETSIG:
|
|
|
|
rc = smk_curacc(file->f_security, MAY_WRITE);
|
|
|
|
break;
|
|
|
|
default:
|
|
|
|
rc = smk_curacc(file->f_security, MAY_READWRITE);
|
|
|
|
}
|
|
|
|
|
|
|
|
return rc;
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_file_set_fowner - set the file security blob value
|
|
|
|
* @file: object in question
|
|
|
|
*
|
|
|
|
* Returns 0
|
|
|
|
* Further research may be required on this one.
|
|
|
|
*/
|
|
|
|
static int smack_file_set_fowner(struct file *file)
|
|
|
|
{
|
|
|
|
file->f_security = current->security;
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_file_send_sigiotask - Smack on sigio
|
|
|
|
* @tsk: The target task
|
|
|
|
* @fown: the object the signal come from
|
|
|
|
* @signum: unused
|
|
|
|
*
|
|
|
|
* Allow a privileged task to get signals even if it shouldn't
|
|
|
|
*
|
|
|
|
* Returns 0 if a subject with the object's smack could
|
|
|
|
* write to the task, an error code otherwise.
|
|
|
|
*/
|
|
|
|
static int smack_file_send_sigiotask(struct task_struct *tsk,
|
|
|
|
struct fown_struct *fown, int signum)
|
|
|
|
{
|
|
|
|
struct file *file;
|
|
|
|
int rc;
|
|
|
|
|
|
|
|
/*
|
|
|
|
* struct fown_struct is never outside the context of a struct file
|
|
|
|
*/
|
|
|
|
file = container_of(fown, struct file, f_owner);
|
|
|
|
rc = smk_access(file->f_security, tsk->security, MAY_WRITE);
|
|
|
|
if (rc != 0 && __capable(tsk, CAP_MAC_OVERRIDE))
|
|
|
|
return 0;
|
|
|
|
return rc;
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_file_receive - Smack file receive check
|
|
|
|
* @file: the object
|
|
|
|
*
|
|
|
|
* Returns 0 if current has access, error code otherwise
|
|
|
|
*/
|
|
|
|
static int smack_file_receive(struct file *file)
|
|
|
|
{
|
|
|
|
int may = 0;
|
|
|
|
|
|
|
|
/*
|
|
|
|
* This code relies on bitmasks.
|
|
|
|
*/
|
|
|
|
if (file->f_mode & FMODE_READ)
|
|
|
|
may = MAY_READ;
|
|
|
|
if (file->f_mode & FMODE_WRITE)
|
|
|
|
may |= MAY_WRITE;
|
|
|
|
|
|
|
|
return smk_curacc(file->f_security, may);
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Task hooks
|
|
|
|
*/
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_task_alloc_security - "allocate" a task blob
|
|
|
|
* @tsk: the task in need of a blob
|
|
|
|
*
|
|
|
|
* Smack isn't using copies of blobs. Everyone
|
|
|
|
* points to an immutable list. No alloc required.
|
|
|
|
* No data copy required.
|
|
|
|
*
|
|
|
|
* Always returns 0
|
|
|
|
*/
|
|
|
|
static int smack_task_alloc_security(struct task_struct *tsk)
|
|
|
|
{
|
|
|
|
tsk->security = current->security;
|
|
|
|
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_task_free_security - "free" a task blob
|
|
|
|
* @task: the task with the blob
|
|
|
|
*
|
|
|
|
* Smack isn't using copies of blobs. Everyone
|
|
|
|
* points to an immutable list. The blobs never go away.
|
|
|
|
* There is no leak here.
|
|
|
|
*/
|
|
|
|
static void smack_task_free_security(struct task_struct *task)
|
|
|
|
{
|
|
|
|
task->security = NULL;
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_task_setpgid - Smack check on setting pgid
|
|
|
|
* @p: the task object
|
|
|
|
* @pgid: unused
|
|
|
|
*
|
|
|
|
* Return 0 if write access is permitted
|
|
|
|
*/
|
|
|
|
static int smack_task_setpgid(struct task_struct *p, pid_t pgid)
|
|
|
|
{
|
|
|
|
return smk_curacc(p->security, MAY_WRITE);
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_task_getpgid - Smack access check for getpgid
|
|
|
|
* @p: the object task
|
|
|
|
*
|
|
|
|
* Returns 0 if current can read the object task, error code otherwise
|
|
|
|
*/
|
|
|
|
static int smack_task_getpgid(struct task_struct *p)
|
|
|
|
{
|
|
|
|
return smk_curacc(p->security, MAY_READ);
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_task_getsid - Smack access check for getsid
|
|
|
|
* @p: the object task
|
|
|
|
*
|
|
|
|
* Returns 0 if current can read the object task, error code otherwise
|
|
|
|
*/
|
|
|
|
static int smack_task_getsid(struct task_struct *p)
|
|
|
|
{
|
|
|
|
return smk_curacc(p->security, MAY_READ);
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_task_getsecid - get the secid of the task
|
|
|
|
* @p: the object task
|
|
|
|
* @secid: where to put the result
|
|
|
|
*
|
|
|
|
* Sets the secid to contain a u32 version of the smack label.
|
|
|
|
*/
|
|
|
|
static void smack_task_getsecid(struct task_struct *p, u32 *secid)
|
|
|
|
{
|
|
|
|
*secid = smack_to_secid(p->security);
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_task_setnice - Smack check on setting nice
|
|
|
|
* @p: the task object
|
|
|
|
* @nice: unused
|
|
|
|
*
|
|
|
|
* Return 0 if write access is permitted
|
|
|
|
*/
|
|
|
|
static int smack_task_setnice(struct task_struct *p, int nice)
|
|
|
|
{
|
2008-02-23 23:24:04 +00:00
|
|
|
int rc;
|
|
|
|
|
|
|
|
rc = cap_task_setnice(p, nice);
|
|
|
|
if (rc == 0)
|
|
|
|
rc = smk_curacc(p->security, MAY_WRITE);
|
|
|
|
return rc;
|
Smack: Simplified Mandatory Access Control Kernel
Smack is the Simplified Mandatory Access Control Kernel.
Smack implements mandatory access control (MAC) using labels
attached to tasks and data containers, including files, SVIPC,
and other tasks. Smack is a kernel based scheme that requires
an absolute minimum of application support and a very small
amount of configuration data.
Smack uses extended attributes and
provides a set of general mount options, borrowing technics used
elsewhere. Smack uses netlabel for CIPSO labeling. Smack provides
a pseudo-filesystem smackfs that is used for manipulation of
system Smack attributes.
The patch, patches for ls and sshd, a README, a startup script,
and x86 binaries for ls and sshd are also available on
http://www.schaufler-ca.com
Development has been done using Fedora Core 7 in a virtual machine
environment and on an old Sony laptop.
Smack provides mandatory access controls based on the label attached
to a task and the label attached to the object it is attempting to
access. Smack labels are deliberately short (1-23 characters) text
strings. Single character labels using special characters are reserved
for system use. The only operation applied to Smack labels is equality
comparison. No wildcards or expressions, regular or otherwise, are
used. Smack labels are composed of printable characters and may not
include "/".
A file always gets the Smack label of the task that created it.
Smack defines and uses these labels:
"*" - pronounced "star"
"_" - pronounced "floor"
"^" - pronounced "hat"
"?" - pronounced "huh"
The access rules enforced by Smack are, in order:
1. Any access requested by a task labeled "*" is denied.
2. A read or execute access requested by a task labeled "^"
is permitted.
3. A read or execute access requested on an object labeled "_"
is permitted.
4. Any access requested on an object labeled "*" is permitted.
5. Any access requested by a task on an object with the same
label is permitted.
6. Any access requested that is explicitly defined in the loaded
rule set is permitted.
7. Any other access is denied.
Rules may be explicitly defined by writing subject,object,access
triples to /smack/load.
Smack rule sets can be easily defined that describe Bell&LaPadula
sensitivity, Biba integrity, and a variety of interesting
configurations. Smack rule sets can be modified on the fly to
accommodate changes in the operating environment or even the time
of day.
Some practical use cases:
Hierarchical levels. The less common of the two usual uses
for MLS systems is to define hierarchical levels, often
unclassified, confidential, secret, and so on. To set up smack
to support this, these rules could be defined:
C Unclass rx
S C rx
S Unclass rx
TS S rx
TS C rx
TS Unclass rx
A TS process can read S, C, and Unclass data, but cannot write it.
An S process can read C and Unclass. Note that specifying that
TS can read S and S can read C does not imply TS can read C, it
has to be explicitly stated.
Non-hierarchical categories. This is the more common of the
usual uses for an MLS system. Since the default rule is that a
subject cannot access an object with a different label no
access rules are required to implement compartmentalization.
A case that the Bell & LaPadula policy does not allow is demonstrated
with this Smack access rule:
A case that Bell&LaPadula does not allow that Smack does:
ESPN ABC r
ABC ESPN r
On my portable video device I have two applications, one that
shows ABC programming and the other ESPN programming. ESPN wants
to show me sport stories that show up as news, and ABC will
only provide minimal information about a sports story if ESPN
is covering it. Each side can look at the other's info, neither
can change the other. Neither can see what FOX is up to, which
is just as well all things considered.
Another case that I especially like:
SatData Guard w
Guard Publish w
A program running with the Guard label opens a UDP socket and
accepts messages sent by a program running with a SatData label.
The Guard program inspects the message to ensure it is wholesome
and if it is sends it to a program running with the Publish label.
This program then puts the information passed in an appropriate
place. Note that the Guard program cannot write to a Publish
file system object because file system semanitic require read as
well as write.
The four cases (categories, levels, mutual read, guardbox) here
are all quite real, and problems I've been asked to solve over
the years. The first two are easy to do with traditonal MLS systems
while the last two you can't without invoking privilege, at least
for a while.
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Cc: Joshua Brindle <method@manicmethod.com>
Cc: Paul Moore <paul.moore@hp.com>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: Chris Wright <chrisw@sous-sol.org>
Cc: James Morris <jmorris@namei.org>
Cc: "Ahmed S. Darwish" <darwish.07@gmail.com>
Cc: Andrew G. Morgan <morgan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-05 06:29:50 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_task_setioprio - Smack check on setting ioprio
|
|
|
|
* @p: the task object
|
|
|
|
* @ioprio: unused
|
|
|
|
*
|
|
|
|
* Return 0 if write access is permitted
|
|
|
|
*/
|
|
|
|
static int smack_task_setioprio(struct task_struct *p, int ioprio)
|
|
|
|
{
|
2008-02-23 23:24:04 +00:00
|
|
|
int rc;
|
|
|
|
|
|
|
|
rc = cap_task_setioprio(p, ioprio);
|
|
|
|
if (rc == 0)
|
|
|
|
rc = smk_curacc(p->security, MAY_WRITE);
|
|
|
|
return rc;
|
Smack: Simplified Mandatory Access Control Kernel
Smack is the Simplified Mandatory Access Control Kernel.
Smack implements mandatory access control (MAC) using labels
attached to tasks and data containers, including files, SVIPC,
and other tasks. Smack is a kernel based scheme that requires
an absolute minimum of application support and a very small
amount of configuration data.
Smack uses extended attributes and
provides a set of general mount options, borrowing technics used
elsewhere. Smack uses netlabel for CIPSO labeling. Smack provides
a pseudo-filesystem smackfs that is used for manipulation of
system Smack attributes.
The patch, patches for ls and sshd, a README, a startup script,
and x86 binaries for ls and sshd are also available on
http://www.schaufler-ca.com
Development has been done using Fedora Core 7 in a virtual machine
environment and on an old Sony laptop.
Smack provides mandatory access controls based on the label attached
to a task and the label attached to the object it is attempting to
access. Smack labels are deliberately short (1-23 characters) text
strings. Single character labels using special characters are reserved
for system use. The only operation applied to Smack labels is equality
comparison. No wildcards or expressions, regular or otherwise, are
used. Smack labels are composed of printable characters and may not
include "/".
A file always gets the Smack label of the task that created it.
Smack defines and uses these labels:
"*" - pronounced "star"
"_" - pronounced "floor"
"^" - pronounced "hat"
"?" - pronounced "huh"
The access rules enforced by Smack are, in order:
1. Any access requested by a task labeled "*" is denied.
2. A read or execute access requested by a task labeled "^"
is permitted.
3. A read or execute access requested on an object labeled "_"
is permitted.
4. Any access requested on an object labeled "*" is permitted.
5. Any access requested by a task on an object with the same
label is permitted.
6. Any access requested that is explicitly defined in the loaded
rule set is permitted.
7. Any other access is denied.
Rules may be explicitly defined by writing subject,object,access
triples to /smack/load.
Smack rule sets can be easily defined that describe Bell&LaPadula
sensitivity, Biba integrity, and a variety of interesting
configurations. Smack rule sets can be modified on the fly to
accommodate changes in the operating environment or even the time
of day.
Some practical use cases:
Hierarchical levels. The less common of the two usual uses
for MLS systems is to define hierarchical levels, often
unclassified, confidential, secret, and so on. To set up smack
to support this, these rules could be defined:
C Unclass rx
S C rx
S Unclass rx
TS S rx
TS C rx
TS Unclass rx
A TS process can read S, C, and Unclass data, but cannot write it.
An S process can read C and Unclass. Note that specifying that
TS can read S and S can read C does not imply TS can read C, it
has to be explicitly stated.
Non-hierarchical categories. This is the more common of the
usual uses for an MLS system. Since the default rule is that a
subject cannot access an object with a different label no
access rules are required to implement compartmentalization.
A case that the Bell & LaPadula policy does not allow is demonstrated
with this Smack access rule:
A case that Bell&LaPadula does not allow that Smack does:
ESPN ABC r
ABC ESPN r
On my portable video device I have two applications, one that
shows ABC programming and the other ESPN programming. ESPN wants
to show me sport stories that show up as news, and ABC will
only provide minimal information about a sports story if ESPN
is covering it. Each side can look at the other's info, neither
can change the other. Neither can see what FOX is up to, which
is just as well all things considered.
Another case that I especially like:
SatData Guard w
Guard Publish w
A program running with the Guard label opens a UDP socket and
accepts messages sent by a program running with a SatData label.
The Guard program inspects the message to ensure it is wholesome
and if it is sends it to a program running with the Publish label.
This program then puts the information passed in an appropriate
place. Note that the Guard program cannot write to a Publish
file system object because file system semanitic require read as
well as write.
The four cases (categories, levels, mutual read, guardbox) here
are all quite real, and problems I've been asked to solve over
the years. The first two are easy to do with traditonal MLS systems
while the last two you can't without invoking privilege, at least
for a while.
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Cc: Joshua Brindle <method@manicmethod.com>
Cc: Paul Moore <paul.moore@hp.com>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: Chris Wright <chrisw@sous-sol.org>
Cc: James Morris <jmorris@namei.org>
Cc: "Ahmed S. Darwish" <darwish.07@gmail.com>
Cc: Andrew G. Morgan <morgan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-05 06:29:50 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_task_getioprio - Smack check on reading ioprio
|
|
|
|
* @p: the task object
|
|
|
|
*
|
|
|
|
* Return 0 if read access is permitted
|
|
|
|
*/
|
|
|
|
static int smack_task_getioprio(struct task_struct *p)
|
|
|
|
{
|
|
|
|
return smk_curacc(p->security, MAY_READ);
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_task_setscheduler - Smack check on setting scheduler
|
|
|
|
* @p: the task object
|
|
|
|
* @policy: unused
|
|
|
|
* @lp: unused
|
|
|
|
*
|
|
|
|
* Return 0 if read access is permitted
|
|
|
|
*/
|
|
|
|
static int smack_task_setscheduler(struct task_struct *p, int policy,
|
|
|
|
struct sched_param *lp)
|
|
|
|
{
|
2008-02-23 23:24:04 +00:00
|
|
|
int rc;
|
|
|
|
|
|
|
|
rc = cap_task_setscheduler(p, policy, lp);
|
|
|
|
if (rc == 0)
|
|
|
|
rc = smk_curacc(p->security, MAY_WRITE);
|
|
|
|
return rc;
|
Smack: Simplified Mandatory Access Control Kernel
Smack is the Simplified Mandatory Access Control Kernel.
Smack implements mandatory access control (MAC) using labels
attached to tasks and data containers, including files, SVIPC,
and other tasks. Smack is a kernel based scheme that requires
an absolute minimum of application support and a very small
amount of configuration data.
Smack uses extended attributes and
provides a set of general mount options, borrowing technics used
elsewhere. Smack uses netlabel for CIPSO labeling. Smack provides
a pseudo-filesystem smackfs that is used for manipulation of
system Smack attributes.
The patch, patches for ls and sshd, a README, a startup script,
and x86 binaries for ls and sshd are also available on
http://www.schaufler-ca.com
Development has been done using Fedora Core 7 in a virtual machine
environment and on an old Sony laptop.
Smack provides mandatory access controls based on the label attached
to a task and the label attached to the object it is attempting to
access. Smack labels are deliberately short (1-23 characters) text
strings. Single character labels using special characters are reserved
for system use. The only operation applied to Smack labels is equality
comparison. No wildcards or expressions, regular or otherwise, are
used. Smack labels are composed of printable characters and may not
include "/".
A file always gets the Smack label of the task that created it.
Smack defines and uses these labels:
"*" - pronounced "star"
"_" - pronounced "floor"
"^" - pronounced "hat"
"?" - pronounced "huh"
The access rules enforced by Smack are, in order:
1. Any access requested by a task labeled "*" is denied.
2. A read or execute access requested by a task labeled "^"
is permitted.
3. A read or execute access requested on an object labeled "_"
is permitted.
4. Any access requested on an object labeled "*" is permitted.
5. Any access requested by a task on an object with the same
label is permitted.
6. Any access requested that is explicitly defined in the loaded
rule set is permitted.
7. Any other access is denied.
Rules may be explicitly defined by writing subject,object,access
triples to /smack/load.
Smack rule sets can be easily defined that describe Bell&LaPadula
sensitivity, Biba integrity, and a variety of interesting
configurations. Smack rule sets can be modified on the fly to
accommodate changes in the operating environment or even the time
of day.
Some practical use cases:
Hierarchical levels. The less common of the two usual uses
for MLS systems is to define hierarchical levels, often
unclassified, confidential, secret, and so on. To set up smack
to support this, these rules could be defined:
C Unclass rx
S C rx
S Unclass rx
TS S rx
TS C rx
TS Unclass rx
A TS process can read S, C, and Unclass data, but cannot write it.
An S process can read C and Unclass. Note that specifying that
TS can read S and S can read C does not imply TS can read C, it
has to be explicitly stated.
Non-hierarchical categories. This is the more common of the
usual uses for an MLS system. Since the default rule is that a
subject cannot access an object with a different label no
access rules are required to implement compartmentalization.
A case that the Bell & LaPadula policy does not allow is demonstrated
with this Smack access rule:
A case that Bell&LaPadula does not allow that Smack does:
ESPN ABC r
ABC ESPN r
On my portable video device I have two applications, one that
shows ABC programming and the other ESPN programming. ESPN wants
to show me sport stories that show up as news, and ABC will
only provide minimal information about a sports story if ESPN
is covering it. Each side can look at the other's info, neither
can change the other. Neither can see what FOX is up to, which
is just as well all things considered.
Another case that I especially like:
SatData Guard w
Guard Publish w
A program running with the Guard label opens a UDP socket and
accepts messages sent by a program running with a SatData label.
The Guard program inspects the message to ensure it is wholesome
and if it is sends it to a program running with the Publish label.
This program then puts the information passed in an appropriate
place. Note that the Guard program cannot write to a Publish
file system object because file system semanitic require read as
well as write.
The four cases (categories, levels, mutual read, guardbox) here
are all quite real, and problems I've been asked to solve over
the years. The first two are easy to do with traditonal MLS systems
while the last two you can't without invoking privilege, at least
for a while.
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Cc: Joshua Brindle <method@manicmethod.com>
Cc: Paul Moore <paul.moore@hp.com>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: Chris Wright <chrisw@sous-sol.org>
Cc: James Morris <jmorris@namei.org>
Cc: "Ahmed S. Darwish" <darwish.07@gmail.com>
Cc: Andrew G. Morgan <morgan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-05 06:29:50 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_task_getscheduler - Smack check on reading scheduler
|
|
|
|
* @p: the task object
|
|
|
|
*
|
|
|
|
* Return 0 if read access is permitted
|
|
|
|
*/
|
|
|
|
static int smack_task_getscheduler(struct task_struct *p)
|
|
|
|
{
|
|
|
|
return smk_curacc(p->security, MAY_READ);
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_task_movememory - Smack check on moving memory
|
|
|
|
* @p: the task object
|
|
|
|
*
|
|
|
|
* Return 0 if write access is permitted
|
|
|
|
*/
|
|
|
|
static int smack_task_movememory(struct task_struct *p)
|
|
|
|
{
|
|
|
|
return smk_curacc(p->security, MAY_WRITE);
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_task_kill - Smack check on signal delivery
|
|
|
|
* @p: the task object
|
|
|
|
* @info: unused
|
|
|
|
* @sig: unused
|
|
|
|
* @secid: identifies the smack to use in lieu of current's
|
|
|
|
*
|
|
|
|
* Return 0 if write access is permitted
|
|
|
|
*
|
|
|
|
* The secid behavior is an artifact of an SELinux hack
|
|
|
|
* in the USB code. Someday it may go away.
|
|
|
|
*/
|
|
|
|
static int smack_task_kill(struct task_struct *p, struct siginfo *info,
|
|
|
|
int sig, u32 secid)
|
|
|
|
{
|
2008-02-23 23:24:04 +00:00
|
|
|
int rc;
|
|
|
|
|
|
|
|
rc = cap_task_kill(p, info, sig, secid);
|
|
|
|
if (rc != 0)
|
|
|
|
return rc;
|
Smack: Simplified Mandatory Access Control Kernel
Smack is the Simplified Mandatory Access Control Kernel.
Smack implements mandatory access control (MAC) using labels
attached to tasks and data containers, including files, SVIPC,
and other tasks. Smack is a kernel based scheme that requires
an absolute minimum of application support and a very small
amount of configuration data.
Smack uses extended attributes and
provides a set of general mount options, borrowing technics used
elsewhere. Smack uses netlabel for CIPSO labeling. Smack provides
a pseudo-filesystem smackfs that is used for manipulation of
system Smack attributes.
The patch, patches for ls and sshd, a README, a startup script,
and x86 binaries for ls and sshd are also available on
http://www.schaufler-ca.com
Development has been done using Fedora Core 7 in a virtual machine
environment and on an old Sony laptop.
Smack provides mandatory access controls based on the label attached
to a task and the label attached to the object it is attempting to
access. Smack labels are deliberately short (1-23 characters) text
strings. Single character labels using special characters are reserved
for system use. The only operation applied to Smack labels is equality
comparison. No wildcards or expressions, regular or otherwise, are
used. Smack labels are composed of printable characters and may not
include "/".
A file always gets the Smack label of the task that created it.
Smack defines and uses these labels:
"*" - pronounced "star"
"_" - pronounced "floor"
"^" - pronounced "hat"
"?" - pronounced "huh"
The access rules enforced by Smack are, in order:
1. Any access requested by a task labeled "*" is denied.
2. A read or execute access requested by a task labeled "^"
is permitted.
3. A read or execute access requested on an object labeled "_"
is permitted.
4. Any access requested on an object labeled "*" is permitted.
5. Any access requested by a task on an object with the same
label is permitted.
6. Any access requested that is explicitly defined in the loaded
rule set is permitted.
7. Any other access is denied.
Rules may be explicitly defined by writing subject,object,access
triples to /smack/load.
Smack rule sets can be easily defined that describe Bell&LaPadula
sensitivity, Biba integrity, and a variety of interesting
configurations. Smack rule sets can be modified on the fly to
accommodate changes in the operating environment or even the time
of day.
Some practical use cases:
Hierarchical levels. The less common of the two usual uses
for MLS systems is to define hierarchical levels, often
unclassified, confidential, secret, and so on. To set up smack
to support this, these rules could be defined:
C Unclass rx
S C rx
S Unclass rx
TS S rx
TS C rx
TS Unclass rx
A TS process can read S, C, and Unclass data, but cannot write it.
An S process can read C and Unclass. Note that specifying that
TS can read S and S can read C does not imply TS can read C, it
has to be explicitly stated.
Non-hierarchical categories. This is the more common of the
usual uses for an MLS system. Since the default rule is that a
subject cannot access an object with a different label no
access rules are required to implement compartmentalization.
A case that the Bell & LaPadula policy does not allow is demonstrated
with this Smack access rule:
A case that Bell&LaPadula does not allow that Smack does:
ESPN ABC r
ABC ESPN r
On my portable video device I have two applications, one that
shows ABC programming and the other ESPN programming. ESPN wants
to show me sport stories that show up as news, and ABC will
only provide minimal information about a sports story if ESPN
is covering it. Each side can look at the other's info, neither
can change the other. Neither can see what FOX is up to, which
is just as well all things considered.
Another case that I especially like:
SatData Guard w
Guard Publish w
A program running with the Guard label opens a UDP socket and
accepts messages sent by a program running with a SatData label.
The Guard program inspects the message to ensure it is wholesome
and if it is sends it to a program running with the Publish label.
This program then puts the information passed in an appropriate
place. Note that the Guard program cannot write to a Publish
file system object because file system semanitic require read as
well as write.
The four cases (categories, levels, mutual read, guardbox) here
are all quite real, and problems I've been asked to solve over
the years. The first two are easy to do with traditonal MLS systems
while the last two you can't without invoking privilege, at least
for a while.
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Cc: Joshua Brindle <method@manicmethod.com>
Cc: Paul Moore <paul.moore@hp.com>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: Chris Wright <chrisw@sous-sol.org>
Cc: James Morris <jmorris@namei.org>
Cc: "Ahmed S. Darwish" <darwish.07@gmail.com>
Cc: Andrew G. Morgan <morgan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-05 06:29:50 +00:00
|
|
|
/*
|
|
|
|
* Special cases where signals really ought to go through
|
|
|
|
* in spite of policy. Stephen Smalley suggests it may
|
|
|
|
* make sense to change the caller so that it doesn't
|
|
|
|
* bother with the LSM hook in these cases.
|
|
|
|
*/
|
|
|
|
if (info != SEND_SIG_NOINFO &&
|
|
|
|
(is_si_special(info) || SI_FROMKERNEL(info)))
|
|
|
|
return 0;
|
|
|
|
/*
|
|
|
|
* Sending a signal requires that the sender
|
|
|
|
* can write the receiver.
|
|
|
|
*/
|
|
|
|
if (secid == 0)
|
|
|
|
return smk_curacc(p->security, MAY_WRITE);
|
|
|
|
/*
|
|
|
|
* If the secid isn't 0 we're dealing with some USB IO
|
|
|
|
* specific behavior. This is not clean. For one thing
|
|
|
|
* we can't take privilege into account.
|
|
|
|
*/
|
|
|
|
return smk_access(smack_from_secid(secid), p->security, MAY_WRITE);
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_task_wait - Smack access check for waiting
|
|
|
|
* @p: task to wait for
|
|
|
|
*
|
|
|
|
* Returns 0 if current can wait for p, error code otherwise
|
|
|
|
*/
|
|
|
|
static int smack_task_wait(struct task_struct *p)
|
|
|
|
{
|
|
|
|
int rc;
|
|
|
|
|
|
|
|
rc = smk_access(current->security, p->security, MAY_WRITE);
|
|
|
|
if (rc == 0)
|
|
|
|
return 0;
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Allow the operation to succeed if either task
|
|
|
|
* has privilege to perform operations that might
|
|
|
|
* account for the smack labels having gotten to
|
|
|
|
* be different in the first place.
|
|
|
|
*
|
|
|
|
* This breaks the strict subjet/object access
|
|
|
|
* control ideal, taking the object's privilege
|
|
|
|
* state into account in the decision as well as
|
|
|
|
* the smack value.
|
|
|
|
*/
|
|
|
|
if (capable(CAP_MAC_OVERRIDE) || __capable(p, CAP_MAC_OVERRIDE))
|
|
|
|
return 0;
|
|
|
|
|
|
|
|
return rc;
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_task_to_inode - copy task smack into the inode blob
|
|
|
|
* @p: task to copy from
|
|
|
|
* inode: inode to copy to
|
|
|
|
*
|
|
|
|
* Sets the smack pointer in the inode security blob
|
|
|
|
*/
|
|
|
|
static void smack_task_to_inode(struct task_struct *p, struct inode *inode)
|
|
|
|
{
|
|
|
|
struct inode_smack *isp = inode->i_security;
|
|
|
|
isp->smk_inode = p->security;
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Socket hooks.
|
|
|
|
*/
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_sk_alloc_security - Allocate a socket blob
|
|
|
|
* @sk: the socket
|
|
|
|
* @family: unused
|
|
|
|
* @priority: memory allocation priority
|
|
|
|
*
|
|
|
|
* Assign Smack pointers to current
|
|
|
|
*
|
|
|
|
* Returns 0 on success, -ENOMEM is there's no memory
|
|
|
|
*/
|
|
|
|
static int smack_sk_alloc_security(struct sock *sk, int family, gfp_t gfp_flags)
|
|
|
|
{
|
|
|
|
char *csp = current->security;
|
|
|
|
struct socket_smack *ssp;
|
|
|
|
|
|
|
|
ssp = kzalloc(sizeof(struct socket_smack), gfp_flags);
|
|
|
|
if (ssp == NULL)
|
|
|
|
return -ENOMEM;
|
|
|
|
|
|
|
|
ssp->smk_in = csp;
|
|
|
|
ssp->smk_out = csp;
|
|
|
|
ssp->smk_packet[0] = '\0';
|
|
|
|
|
|
|
|
sk->sk_security = ssp;
|
|
|
|
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_sk_free_security - Free a socket blob
|
|
|
|
* @sk: the socket
|
|
|
|
*
|
|
|
|
* Clears the blob pointer
|
|
|
|
*/
|
|
|
|
static void smack_sk_free_security(struct sock *sk)
|
|
|
|
{
|
|
|
|
kfree(sk->sk_security);
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_set_catset - convert a capset to netlabel mls categories
|
|
|
|
* @catset: the Smack categories
|
|
|
|
* @sap: where to put the netlabel categories
|
|
|
|
*
|
|
|
|
* Allocates and fills attr.mls.cat
|
|
|
|
*/
|
|
|
|
static void smack_set_catset(char *catset, struct netlbl_lsm_secattr *sap)
|
|
|
|
{
|
|
|
|
unsigned char *cp;
|
|
|
|
unsigned char m;
|
|
|
|
int cat;
|
|
|
|
int rc;
|
|
|
|
int byte;
|
|
|
|
|
|
|
|
if (catset == 0)
|
|
|
|
return;
|
|
|
|
|
|
|
|
sap->flags |= NETLBL_SECATTR_MLS_CAT;
|
|
|
|
sap->attr.mls.cat = netlbl_secattr_catmap_alloc(GFP_ATOMIC);
|
|
|
|
sap->attr.mls.cat->startbit = 0;
|
|
|
|
|
|
|
|
for (cat = 1, cp = catset, byte = 0; byte < SMK_LABELLEN; cp++, byte++)
|
|
|
|
for (m = 0x80; m != 0; m >>= 1, cat++) {
|
|
|
|
if ((m & *cp) == 0)
|
|
|
|
continue;
|
|
|
|
rc = netlbl_secattr_catmap_setbit(sap->attr.mls.cat,
|
|
|
|
cat, GFP_ATOMIC);
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_to_secattr - fill a secattr from a smack value
|
|
|
|
* @smack: the smack value
|
|
|
|
* @nlsp: where the result goes
|
|
|
|
*
|
|
|
|
* Casey says that CIPSO is good enough for now.
|
|
|
|
* It can be used to effect.
|
|
|
|
* It can also be abused to effect when necessary.
|
|
|
|
* Appologies to the TSIG group in general and GW in particular.
|
|
|
|
*/
|
|
|
|
static void smack_to_secattr(char *smack, struct netlbl_lsm_secattr *nlsp)
|
|
|
|
{
|
|
|
|
struct smack_cipso cipso;
|
|
|
|
int rc;
|
|
|
|
|
|
|
|
switch (smack_net_nltype) {
|
|
|
|
case NETLBL_NLTYPE_CIPSOV4:
|
2008-02-15 23:24:25 +00:00
|
|
|
nlsp->domain = kstrdup(smack, GFP_ATOMIC);
|
|
|
|
nlsp->flags = NETLBL_SECATTR_DOMAIN | NETLBL_SECATTR_MLS_LVL;
|
Smack: Simplified Mandatory Access Control Kernel
Smack is the Simplified Mandatory Access Control Kernel.
Smack implements mandatory access control (MAC) using labels
attached to tasks and data containers, including files, SVIPC,
and other tasks. Smack is a kernel based scheme that requires
an absolute minimum of application support and a very small
amount of configuration data.
Smack uses extended attributes and
provides a set of general mount options, borrowing technics used
elsewhere. Smack uses netlabel for CIPSO labeling. Smack provides
a pseudo-filesystem smackfs that is used for manipulation of
system Smack attributes.
The patch, patches for ls and sshd, a README, a startup script,
and x86 binaries for ls and sshd are also available on
http://www.schaufler-ca.com
Development has been done using Fedora Core 7 in a virtual machine
environment and on an old Sony laptop.
Smack provides mandatory access controls based on the label attached
to a task and the label attached to the object it is attempting to
access. Smack labels are deliberately short (1-23 characters) text
strings. Single character labels using special characters are reserved
for system use. The only operation applied to Smack labels is equality
comparison. No wildcards or expressions, regular or otherwise, are
used. Smack labels are composed of printable characters and may not
include "/".
A file always gets the Smack label of the task that created it.
Smack defines and uses these labels:
"*" - pronounced "star"
"_" - pronounced "floor"
"^" - pronounced "hat"
"?" - pronounced "huh"
The access rules enforced by Smack are, in order:
1. Any access requested by a task labeled "*" is denied.
2. A read or execute access requested by a task labeled "^"
is permitted.
3. A read or execute access requested on an object labeled "_"
is permitted.
4. Any access requested on an object labeled "*" is permitted.
5. Any access requested by a task on an object with the same
label is permitted.
6. Any access requested that is explicitly defined in the loaded
rule set is permitted.
7. Any other access is denied.
Rules may be explicitly defined by writing subject,object,access
triples to /smack/load.
Smack rule sets can be easily defined that describe Bell&LaPadula
sensitivity, Biba integrity, and a variety of interesting
configurations. Smack rule sets can be modified on the fly to
accommodate changes in the operating environment or even the time
of day.
Some practical use cases:
Hierarchical levels. The less common of the two usual uses
for MLS systems is to define hierarchical levels, often
unclassified, confidential, secret, and so on. To set up smack
to support this, these rules could be defined:
C Unclass rx
S C rx
S Unclass rx
TS S rx
TS C rx
TS Unclass rx
A TS process can read S, C, and Unclass data, but cannot write it.
An S process can read C and Unclass. Note that specifying that
TS can read S and S can read C does not imply TS can read C, it
has to be explicitly stated.
Non-hierarchical categories. This is the more common of the
usual uses for an MLS system. Since the default rule is that a
subject cannot access an object with a different label no
access rules are required to implement compartmentalization.
A case that the Bell & LaPadula policy does not allow is demonstrated
with this Smack access rule:
A case that Bell&LaPadula does not allow that Smack does:
ESPN ABC r
ABC ESPN r
On my portable video device I have two applications, one that
shows ABC programming and the other ESPN programming. ESPN wants
to show me sport stories that show up as news, and ABC will
only provide minimal information about a sports story if ESPN
is covering it. Each side can look at the other's info, neither
can change the other. Neither can see what FOX is up to, which
is just as well all things considered.
Another case that I especially like:
SatData Guard w
Guard Publish w
A program running with the Guard label opens a UDP socket and
accepts messages sent by a program running with a SatData label.
The Guard program inspects the message to ensure it is wholesome
and if it is sends it to a program running with the Publish label.
This program then puts the information passed in an appropriate
place. Note that the Guard program cannot write to a Publish
file system object because file system semanitic require read as
well as write.
The four cases (categories, levels, mutual read, guardbox) here
are all quite real, and problems I've been asked to solve over
the years. The first two are easy to do with traditonal MLS systems
while the last two you can't without invoking privilege, at least
for a while.
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Cc: Joshua Brindle <method@manicmethod.com>
Cc: Paul Moore <paul.moore@hp.com>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: Chris Wright <chrisw@sous-sol.org>
Cc: James Morris <jmorris@namei.org>
Cc: "Ahmed S. Darwish" <darwish.07@gmail.com>
Cc: Andrew G. Morgan <morgan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-05 06:29:50 +00:00
|
|
|
|
|
|
|
rc = smack_to_cipso(smack, &cipso);
|
|
|
|
if (rc == 0) {
|
|
|
|
nlsp->attr.mls.lvl = cipso.smk_level;
|
|
|
|
smack_set_catset(cipso.smk_catset, nlsp);
|
|
|
|
} else {
|
|
|
|
nlsp->attr.mls.lvl = smack_cipso_direct;
|
|
|
|
smack_set_catset(smack, nlsp);
|
|
|
|
}
|
|
|
|
break;
|
|
|
|
default:
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_netlabel - Set the secattr on a socket
|
|
|
|
* @sk: the socket
|
|
|
|
*
|
|
|
|
* Convert the outbound smack value (smk_out) to a
|
|
|
|
* secattr and attach it to the socket.
|
|
|
|
*
|
|
|
|
* Returns 0 on success or an error code
|
|
|
|
*/
|
|
|
|
static int smack_netlabel(struct sock *sk)
|
|
|
|
{
|
2008-02-13 23:03:34 +00:00
|
|
|
struct socket_smack *ssp;
|
Smack: Simplified Mandatory Access Control Kernel
Smack is the Simplified Mandatory Access Control Kernel.
Smack implements mandatory access control (MAC) using labels
attached to tasks and data containers, including files, SVIPC,
and other tasks. Smack is a kernel based scheme that requires
an absolute minimum of application support and a very small
amount of configuration data.
Smack uses extended attributes and
provides a set of general mount options, borrowing technics used
elsewhere. Smack uses netlabel for CIPSO labeling. Smack provides
a pseudo-filesystem smackfs that is used for manipulation of
system Smack attributes.
The patch, patches for ls and sshd, a README, a startup script,
and x86 binaries for ls and sshd are also available on
http://www.schaufler-ca.com
Development has been done using Fedora Core 7 in a virtual machine
environment and on an old Sony laptop.
Smack provides mandatory access controls based on the label attached
to a task and the label attached to the object it is attempting to
access. Smack labels are deliberately short (1-23 characters) text
strings. Single character labels using special characters are reserved
for system use. The only operation applied to Smack labels is equality
comparison. No wildcards or expressions, regular or otherwise, are
used. Smack labels are composed of printable characters and may not
include "/".
A file always gets the Smack label of the task that created it.
Smack defines and uses these labels:
"*" - pronounced "star"
"_" - pronounced "floor"
"^" - pronounced "hat"
"?" - pronounced "huh"
The access rules enforced by Smack are, in order:
1. Any access requested by a task labeled "*" is denied.
2. A read or execute access requested by a task labeled "^"
is permitted.
3. A read or execute access requested on an object labeled "_"
is permitted.
4. Any access requested on an object labeled "*" is permitted.
5. Any access requested by a task on an object with the same
label is permitted.
6. Any access requested that is explicitly defined in the loaded
rule set is permitted.
7. Any other access is denied.
Rules may be explicitly defined by writing subject,object,access
triples to /smack/load.
Smack rule sets can be easily defined that describe Bell&LaPadula
sensitivity, Biba integrity, and a variety of interesting
configurations. Smack rule sets can be modified on the fly to
accommodate changes in the operating environment or even the time
of day.
Some practical use cases:
Hierarchical levels. The less common of the two usual uses
for MLS systems is to define hierarchical levels, often
unclassified, confidential, secret, and so on. To set up smack
to support this, these rules could be defined:
C Unclass rx
S C rx
S Unclass rx
TS S rx
TS C rx
TS Unclass rx
A TS process can read S, C, and Unclass data, but cannot write it.
An S process can read C and Unclass. Note that specifying that
TS can read S and S can read C does not imply TS can read C, it
has to be explicitly stated.
Non-hierarchical categories. This is the more common of the
usual uses for an MLS system. Since the default rule is that a
subject cannot access an object with a different label no
access rules are required to implement compartmentalization.
A case that the Bell & LaPadula policy does not allow is demonstrated
with this Smack access rule:
A case that Bell&LaPadula does not allow that Smack does:
ESPN ABC r
ABC ESPN r
On my portable video device I have two applications, one that
shows ABC programming and the other ESPN programming. ESPN wants
to show me sport stories that show up as news, and ABC will
only provide minimal information about a sports story if ESPN
is covering it. Each side can look at the other's info, neither
can change the other. Neither can see what FOX is up to, which
is just as well all things considered.
Another case that I especially like:
SatData Guard w
Guard Publish w
A program running with the Guard label opens a UDP socket and
accepts messages sent by a program running with a SatData label.
The Guard program inspects the message to ensure it is wholesome
and if it is sends it to a program running with the Publish label.
This program then puts the information passed in an appropriate
place. Note that the Guard program cannot write to a Publish
file system object because file system semanitic require read as
well as write.
The four cases (categories, levels, mutual read, guardbox) here
are all quite real, and problems I've been asked to solve over
the years. The first two are easy to do with traditonal MLS systems
while the last two you can't without invoking privilege, at least
for a while.
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Cc: Joshua Brindle <method@manicmethod.com>
Cc: Paul Moore <paul.moore@hp.com>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: Chris Wright <chrisw@sous-sol.org>
Cc: James Morris <jmorris@namei.org>
Cc: "Ahmed S. Darwish" <darwish.07@gmail.com>
Cc: Andrew G. Morgan <morgan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-05 06:29:50 +00:00
|
|
|
struct netlbl_lsm_secattr secattr;
|
2008-02-15 23:24:25 +00:00
|
|
|
int rc;
|
Smack: Simplified Mandatory Access Control Kernel
Smack is the Simplified Mandatory Access Control Kernel.
Smack implements mandatory access control (MAC) using labels
attached to tasks and data containers, including files, SVIPC,
and other tasks. Smack is a kernel based scheme that requires
an absolute minimum of application support and a very small
amount of configuration data.
Smack uses extended attributes and
provides a set of general mount options, borrowing technics used
elsewhere. Smack uses netlabel for CIPSO labeling. Smack provides
a pseudo-filesystem smackfs that is used for manipulation of
system Smack attributes.
The patch, patches for ls and sshd, a README, a startup script,
and x86 binaries for ls and sshd are also available on
http://www.schaufler-ca.com
Development has been done using Fedora Core 7 in a virtual machine
environment and on an old Sony laptop.
Smack provides mandatory access controls based on the label attached
to a task and the label attached to the object it is attempting to
access. Smack labels are deliberately short (1-23 characters) text
strings. Single character labels using special characters are reserved
for system use. The only operation applied to Smack labels is equality
comparison. No wildcards or expressions, regular or otherwise, are
used. Smack labels are composed of printable characters and may not
include "/".
A file always gets the Smack label of the task that created it.
Smack defines and uses these labels:
"*" - pronounced "star"
"_" - pronounced "floor"
"^" - pronounced "hat"
"?" - pronounced "huh"
The access rules enforced by Smack are, in order:
1. Any access requested by a task labeled "*" is denied.
2. A read or execute access requested by a task labeled "^"
is permitted.
3. A read or execute access requested on an object labeled "_"
is permitted.
4. Any access requested on an object labeled "*" is permitted.
5. Any access requested by a task on an object with the same
label is permitted.
6. Any access requested that is explicitly defined in the loaded
rule set is permitted.
7. Any other access is denied.
Rules may be explicitly defined by writing subject,object,access
triples to /smack/load.
Smack rule sets can be easily defined that describe Bell&LaPadula
sensitivity, Biba integrity, and a variety of interesting
configurations. Smack rule sets can be modified on the fly to
accommodate changes in the operating environment or even the time
of day.
Some practical use cases:
Hierarchical levels. The less common of the two usual uses
for MLS systems is to define hierarchical levels, often
unclassified, confidential, secret, and so on. To set up smack
to support this, these rules could be defined:
C Unclass rx
S C rx
S Unclass rx
TS S rx
TS C rx
TS Unclass rx
A TS process can read S, C, and Unclass data, but cannot write it.
An S process can read C and Unclass. Note that specifying that
TS can read S and S can read C does not imply TS can read C, it
has to be explicitly stated.
Non-hierarchical categories. This is the more common of the
usual uses for an MLS system. Since the default rule is that a
subject cannot access an object with a different label no
access rules are required to implement compartmentalization.
A case that the Bell & LaPadula policy does not allow is demonstrated
with this Smack access rule:
A case that Bell&LaPadula does not allow that Smack does:
ESPN ABC r
ABC ESPN r
On my portable video device I have two applications, one that
shows ABC programming and the other ESPN programming. ESPN wants
to show me sport stories that show up as news, and ABC will
only provide minimal information about a sports story if ESPN
is covering it. Each side can look at the other's info, neither
can change the other. Neither can see what FOX is up to, which
is just as well all things considered.
Another case that I especially like:
SatData Guard w
Guard Publish w
A program running with the Guard label opens a UDP socket and
accepts messages sent by a program running with a SatData label.
The Guard program inspects the message to ensure it is wholesome
and if it is sends it to a program running with the Publish label.
This program then puts the information passed in an appropriate
place. Note that the Guard program cannot write to a Publish
file system object because file system semanitic require read as
well as write.
The four cases (categories, levels, mutual read, guardbox) here
are all quite real, and problems I've been asked to solve over
the years. The first two are easy to do with traditonal MLS systems
while the last two you can't without invoking privilege, at least
for a while.
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Cc: Joshua Brindle <method@manicmethod.com>
Cc: Paul Moore <paul.moore@hp.com>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: Chris Wright <chrisw@sous-sol.org>
Cc: James Morris <jmorris@namei.org>
Cc: "Ahmed S. Darwish" <darwish.07@gmail.com>
Cc: Andrew G. Morgan <morgan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-05 06:29:50 +00:00
|
|
|
|
2008-02-13 23:03:34 +00:00
|
|
|
ssp = sk->sk_security;
|
Smack: Simplified Mandatory Access Control Kernel
Smack is the Simplified Mandatory Access Control Kernel.
Smack implements mandatory access control (MAC) using labels
attached to tasks and data containers, including files, SVIPC,
and other tasks. Smack is a kernel based scheme that requires
an absolute minimum of application support and a very small
amount of configuration data.
Smack uses extended attributes and
provides a set of general mount options, borrowing technics used
elsewhere. Smack uses netlabel for CIPSO labeling. Smack provides
a pseudo-filesystem smackfs that is used for manipulation of
system Smack attributes.
The patch, patches for ls and sshd, a README, a startup script,
and x86 binaries for ls and sshd are also available on
http://www.schaufler-ca.com
Development has been done using Fedora Core 7 in a virtual machine
environment and on an old Sony laptop.
Smack provides mandatory access controls based on the label attached
to a task and the label attached to the object it is attempting to
access. Smack labels are deliberately short (1-23 characters) text
strings. Single character labels using special characters are reserved
for system use. The only operation applied to Smack labels is equality
comparison. No wildcards or expressions, regular or otherwise, are
used. Smack labels are composed of printable characters and may not
include "/".
A file always gets the Smack label of the task that created it.
Smack defines and uses these labels:
"*" - pronounced "star"
"_" - pronounced "floor"
"^" - pronounced "hat"
"?" - pronounced "huh"
The access rules enforced by Smack are, in order:
1. Any access requested by a task labeled "*" is denied.
2. A read or execute access requested by a task labeled "^"
is permitted.
3. A read or execute access requested on an object labeled "_"
is permitted.
4. Any access requested on an object labeled "*" is permitted.
5. Any access requested by a task on an object with the same
label is permitted.
6. Any access requested that is explicitly defined in the loaded
rule set is permitted.
7. Any other access is denied.
Rules may be explicitly defined by writing subject,object,access
triples to /smack/load.
Smack rule sets can be easily defined that describe Bell&LaPadula
sensitivity, Biba integrity, and a variety of interesting
configurations. Smack rule sets can be modified on the fly to
accommodate changes in the operating environment or even the time
of day.
Some practical use cases:
Hierarchical levels. The less common of the two usual uses
for MLS systems is to define hierarchical levels, often
unclassified, confidential, secret, and so on. To set up smack
to support this, these rules could be defined:
C Unclass rx
S C rx
S Unclass rx
TS S rx
TS C rx
TS Unclass rx
A TS process can read S, C, and Unclass data, but cannot write it.
An S process can read C and Unclass. Note that specifying that
TS can read S and S can read C does not imply TS can read C, it
has to be explicitly stated.
Non-hierarchical categories. This is the more common of the
usual uses for an MLS system. Since the default rule is that a
subject cannot access an object with a different label no
access rules are required to implement compartmentalization.
A case that the Bell & LaPadula policy does not allow is demonstrated
with this Smack access rule:
A case that Bell&LaPadula does not allow that Smack does:
ESPN ABC r
ABC ESPN r
On my portable video device I have two applications, one that
shows ABC programming and the other ESPN programming. ESPN wants
to show me sport stories that show up as news, and ABC will
only provide minimal information about a sports story if ESPN
is covering it. Each side can look at the other's info, neither
can change the other. Neither can see what FOX is up to, which
is just as well all things considered.
Another case that I especially like:
SatData Guard w
Guard Publish w
A program running with the Guard label opens a UDP socket and
accepts messages sent by a program running with a SatData label.
The Guard program inspects the message to ensure it is wholesome
and if it is sends it to a program running with the Publish label.
This program then puts the information passed in an appropriate
place. Note that the Guard program cannot write to a Publish
file system object because file system semanitic require read as
well as write.
The four cases (categories, levels, mutual read, guardbox) here
are all quite real, and problems I've been asked to solve over
the years. The first two are easy to do with traditonal MLS systems
while the last two you can't without invoking privilege, at least
for a while.
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Cc: Joshua Brindle <method@manicmethod.com>
Cc: Paul Moore <paul.moore@hp.com>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: Chris Wright <chrisw@sous-sol.org>
Cc: James Morris <jmorris@namei.org>
Cc: "Ahmed S. Darwish" <darwish.07@gmail.com>
Cc: Andrew G. Morgan <morgan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-05 06:29:50 +00:00
|
|
|
netlbl_secattr_init(&secattr);
|
|
|
|
smack_to_secattr(ssp->smk_out, &secattr);
|
2008-02-15 23:24:25 +00:00
|
|
|
rc = netlbl_sock_setattr(sk, &secattr);
|
Smack: Simplified Mandatory Access Control Kernel
Smack is the Simplified Mandatory Access Control Kernel.
Smack implements mandatory access control (MAC) using labels
attached to tasks and data containers, including files, SVIPC,
and other tasks. Smack is a kernel based scheme that requires
an absolute minimum of application support and a very small
amount of configuration data.
Smack uses extended attributes and
provides a set of general mount options, borrowing technics used
elsewhere. Smack uses netlabel for CIPSO labeling. Smack provides
a pseudo-filesystem smackfs that is used for manipulation of
system Smack attributes.
The patch, patches for ls and sshd, a README, a startup script,
and x86 binaries for ls and sshd are also available on
http://www.schaufler-ca.com
Development has been done using Fedora Core 7 in a virtual machine
environment and on an old Sony laptop.
Smack provides mandatory access controls based on the label attached
to a task and the label attached to the object it is attempting to
access. Smack labels are deliberately short (1-23 characters) text
strings. Single character labels using special characters are reserved
for system use. The only operation applied to Smack labels is equality
comparison. No wildcards or expressions, regular or otherwise, are
used. Smack labels are composed of printable characters and may not
include "/".
A file always gets the Smack label of the task that created it.
Smack defines and uses these labels:
"*" - pronounced "star"
"_" - pronounced "floor"
"^" - pronounced "hat"
"?" - pronounced "huh"
The access rules enforced by Smack are, in order:
1. Any access requested by a task labeled "*" is denied.
2. A read or execute access requested by a task labeled "^"
is permitted.
3. A read or execute access requested on an object labeled "_"
is permitted.
4. Any access requested on an object labeled "*" is permitted.
5. Any access requested by a task on an object with the same
label is permitted.
6. Any access requested that is explicitly defined in the loaded
rule set is permitted.
7. Any other access is denied.
Rules may be explicitly defined by writing subject,object,access
triples to /smack/load.
Smack rule sets can be easily defined that describe Bell&LaPadula
sensitivity, Biba integrity, and a variety of interesting
configurations. Smack rule sets can be modified on the fly to
accommodate changes in the operating environment or even the time
of day.
Some practical use cases:
Hierarchical levels. The less common of the two usual uses
for MLS systems is to define hierarchical levels, often
unclassified, confidential, secret, and so on. To set up smack
to support this, these rules could be defined:
C Unclass rx
S C rx
S Unclass rx
TS S rx
TS C rx
TS Unclass rx
A TS process can read S, C, and Unclass data, but cannot write it.
An S process can read C and Unclass. Note that specifying that
TS can read S and S can read C does not imply TS can read C, it
has to be explicitly stated.
Non-hierarchical categories. This is the more common of the
usual uses for an MLS system. Since the default rule is that a
subject cannot access an object with a different label no
access rules are required to implement compartmentalization.
A case that the Bell & LaPadula policy does not allow is demonstrated
with this Smack access rule:
A case that Bell&LaPadula does not allow that Smack does:
ESPN ABC r
ABC ESPN r
On my portable video device I have two applications, one that
shows ABC programming and the other ESPN programming. ESPN wants
to show me sport stories that show up as news, and ABC will
only provide minimal information about a sports story if ESPN
is covering it. Each side can look at the other's info, neither
can change the other. Neither can see what FOX is up to, which
is just as well all things considered.
Another case that I especially like:
SatData Guard w
Guard Publish w
A program running with the Guard label opens a UDP socket and
accepts messages sent by a program running with a SatData label.
The Guard program inspects the message to ensure it is wholesome
and if it is sends it to a program running with the Publish label.
This program then puts the information passed in an appropriate
place. Note that the Guard program cannot write to a Publish
file system object because file system semanitic require read as
well as write.
The four cases (categories, levels, mutual read, guardbox) here
are all quite real, and problems I've been asked to solve over
the years. The first two are easy to do with traditonal MLS systems
while the last two you can't without invoking privilege, at least
for a while.
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Cc: Joshua Brindle <method@manicmethod.com>
Cc: Paul Moore <paul.moore@hp.com>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: Chris Wright <chrisw@sous-sol.org>
Cc: James Morris <jmorris@namei.org>
Cc: "Ahmed S. Darwish" <darwish.07@gmail.com>
Cc: Andrew G. Morgan <morgan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-05 06:29:50 +00:00
|
|
|
netlbl_secattr_destroy(&secattr);
|
2008-02-15 23:24:25 +00:00
|
|
|
|
Smack: Simplified Mandatory Access Control Kernel
Smack is the Simplified Mandatory Access Control Kernel.
Smack implements mandatory access control (MAC) using labels
attached to tasks and data containers, including files, SVIPC,
and other tasks. Smack is a kernel based scheme that requires
an absolute minimum of application support and a very small
amount of configuration data.
Smack uses extended attributes and
provides a set of general mount options, borrowing technics used
elsewhere. Smack uses netlabel for CIPSO labeling. Smack provides
a pseudo-filesystem smackfs that is used for manipulation of
system Smack attributes.
The patch, patches for ls and sshd, a README, a startup script,
and x86 binaries for ls and sshd are also available on
http://www.schaufler-ca.com
Development has been done using Fedora Core 7 in a virtual machine
environment and on an old Sony laptop.
Smack provides mandatory access controls based on the label attached
to a task and the label attached to the object it is attempting to
access. Smack labels are deliberately short (1-23 characters) text
strings. Single character labels using special characters are reserved
for system use. The only operation applied to Smack labels is equality
comparison. No wildcards or expressions, regular or otherwise, are
used. Smack labels are composed of printable characters and may not
include "/".
A file always gets the Smack label of the task that created it.
Smack defines and uses these labels:
"*" - pronounced "star"
"_" - pronounced "floor"
"^" - pronounced "hat"
"?" - pronounced "huh"
The access rules enforced by Smack are, in order:
1. Any access requested by a task labeled "*" is denied.
2. A read or execute access requested by a task labeled "^"
is permitted.
3. A read or execute access requested on an object labeled "_"
is permitted.
4. Any access requested on an object labeled "*" is permitted.
5. Any access requested by a task on an object with the same
label is permitted.
6. Any access requested that is explicitly defined in the loaded
rule set is permitted.
7. Any other access is denied.
Rules may be explicitly defined by writing subject,object,access
triples to /smack/load.
Smack rule sets can be easily defined that describe Bell&LaPadula
sensitivity, Biba integrity, and a variety of interesting
configurations. Smack rule sets can be modified on the fly to
accommodate changes in the operating environment or even the time
of day.
Some practical use cases:
Hierarchical levels. The less common of the two usual uses
for MLS systems is to define hierarchical levels, often
unclassified, confidential, secret, and so on. To set up smack
to support this, these rules could be defined:
C Unclass rx
S C rx
S Unclass rx
TS S rx
TS C rx
TS Unclass rx
A TS process can read S, C, and Unclass data, but cannot write it.
An S process can read C and Unclass. Note that specifying that
TS can read S and S can read C does not imply TS can read C, it
has to be explicitly stated.
Non-hierarchical categories. This is the more common of the
usual uses for an MLS system. Since the default rule is that a
subject cannot access an object with a different label no
access rules are required to implement compartmentalization.
A case that the Bell & LaPadula policy does not allow is demonstrated
with this Smack access rule:
A case that Bell&LaPadula does not allow that Smack does:
ESPN ABC r
ABC ESPN r
On my portable video device I have two applications, one that
shows ABC programming and the other ESPN programming. ESPN wants
to show me sport stories that show up as news, and ABC will
only provide minimal information about a sports story if ESPN
is covering it. Each side can look at the other's info, neither
can change the other. Neither can see what FOX is up to, which
is just as well all things considered.
Another case that I especially like:
SatData Guard w
Guard Publish w
A program running with the Guard label opens a UDP socket and
accepts messages sent by a program running with a SatData label.
The Guard program inspects the message to ensure it is wholesome
and if it is sends it to a program running with the Publish label.
This program then puts the information passed in an appropriate
place. Note that the Guard program cannot write to a Publish
file system object because file system semanitic require read as
well as write.
The four cases (categories, levels, mutual read, guardbox) here
are all quite real, and problems I've been asked to solve over
the years. The first two are easy to do with traditonal MLS systems
while the last two you can't without invoking privilege, at least
for a while.
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Cc: Joshua Brindle <method@manicmethod.com>
Cc: Paul Moore <paul.moore@hp.com>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: Chris Wright <chrisw@sous-sol.org>
Cc: James Morris <jmorris@namei.org>
Cc: "Ahmed S. Darwish" <darwish.07@gmail.com>
Cc: Andrew G. Morgan <morgan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-05 06:29:50 +00:00
|
|
|
return rc;
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_inode_setsecurity - set smack xattrs
|
|
|
|
* @inode: the object
|
|
|
|
* @name: attribute name
|
|
|
|
* @value: attribute value
|
|
|
|
* @size: size of the attribute
|
|
|
|
* @flags: unused
|
|
|
|
*
|
|
|
|
* Sets the named attribute in the appropriate blob
|
|
|
|
*
|
|
|
|
* Returns 0 on success, or an error code
|
|
|
|
*/
|
|
|
|
static int smack_inode_setsecurity(struct inode *inode, const char *name,
|
|
|
|
const void *value, size_t size, int flags)
|
|
|
|
{
|
|
|
|
char *sp;
|
|
|
|
struct inode_smack *nsp = inode->i_security;
|
|
|
|
struct socket_smack *ssp;
|
|
|
|
struct socket *sock;
|
2008-02-15 23:24:25 +00:00
|
|
|
int rc = 0;
|
Smack: Simplified Mandatory Access Control Kernel
Smack is the Simplified Mandatory Access Control Kernel.
Smack implements mandatory access control (MAC) using labels
attached to tasks and data containers, including files, SVIPC,
and other tasks. Smack is a kernel based scheme that requires
an absolute minimum of application support and a very small
amount of configuration data.
Smack uses extended attributes and
provides a set of general mount options, borrowing technics used
elsewhere. Smack uses netlabel for CIPSO labeling. Smack provides
a pseudo-filesystem smackfs that is used for manipulation of
system Smack attributes.
The patch, patches for ls and sshd, a README, a startup script,
and x86 binaries for ls and sshd are also available on
http://www.schaufler-ca.com
Development has been done using Fedora Core 7 in a virtual machine
environment and on an old Sony laptop.
Smack provides mandatory access controls based on the label attached
to a task and the label attached to the object it is attempting to
access. Smack labels are deliberately short (1-23 characters) text
strings. Single character labels using special characters are reserved
for system use. The only operation applied to Smack labels is equality
comparison. No wildcards or expressions, regular or otherwise, are
used. Smack labels are composed of printable characters and may not
include "/".
A file always gets the Smack label of the task that created it.
Smack defines and uses these labels:
"*" - pronounced "star"
"_" - pronounced "floor"
"^" - pronounced "hat"
"?" - pronounced "huh"
The access rules enforced by Smack are, in order:
1. Any access requested by a task labeled "*" is denied.
2. A read or execute access requested by a task labeled "^"
is permitted.
3. A read or execute access requested on an object labeled "_"
is permitted.
4. Any access requested on an object labeled "*" is permitted.
5. Any access requested by a task on an object with the same
label is permitted.
6. Any access requested that is explicitly defined in the loaded
rule set is permitted.
7. Any other access is denied.
Rules may be explicitly defined by writing subject,object,access
triples to /smack/load.
Smack rule sets can be easily defined that describe Bell&LaPadula
sensitivity, Biba integrity, and a variety of interesting
configurations. Smack rule sets can be modified on the fly to
accommodate changes in the operating environment or even the time
of day.
Some practical use cases:
Hierarchical levels. The less common of the two usual uses
for MLS systems is to define hierarchical levels, often
unclassified, confidential, secret, and so on. To set up smack
to support this, these rules could be defined:
C Unclass rx
S C rx
S Unclass rx
TS S rx
TS C rx
TS Unclass rx
A TS process can read S, C, and Unclass data, but cannot write it.
An S process can read C and Unclass. Note that specifying that
TS can read S and S can read C does not imply TS can read C, it
has to be explicitly stated.
Non-hierarchical categories. This is the more common of the
usual uses for an MLS system. Since the default rule is that a
subject cannot access an object with a different label no
access rules are required to implement compartmentalization.
A case that the Bell & LaPadula policy does not allow is demonstrated
with this Smack access rule:
A case that Bell&LaPadula does not allow that Smack does:
ESPN ABC r
ABC ESPN r
On my portable video device I have two applications, one that
shows ABC programming and the other ESPN programming. ESPN wants
to show me sport stories that show up as news, and ABC will
only provide minimal information about a sports story if ESPN
is covering it. Each side can look at the other's info, neither
can change the other. Neither can see what FOX is up to, which
is just as well all things considered.
Another case that I especially like:
SatData Guard w
Guard Publish w
A program running with the Guard label opens a UDP socket and
accepts messages sent by a program running with a SatData label.
The Guard program inspects the message to ensure it is wholesome
and if it is sends it to a program running with the Publish label.
This program then puts the information passed in an appropriate
place. Note that the Guard program cannot write to a Publish
file system object because file system semanitic require read as
well as write.
The four cases (categories, levels, mutual read, guardbox) here
are all quite real, and problems I've been asked to solve over
the years. The first two are easy to do with traditonal MLS systems
while the last two you can't without invoking privilege, at least
for a while.
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Cc: Joshua Brindle <method@manicmethod.com>
Cc: Paul Moore <paul.moore@hp.com>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: Chris Wright <chrisw@sous-sol.org>
Cc: James Morris <jmorris@namei.org>
Cc: "Ahmed S. Darwish" <darwish.07@gmail.com>
Cc: Andrew G. Morgan <morgan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-05 06:29:50 +00:00
|
|
|
|
|
|
|
if (value == NULL || size > SMK_LABELLEN)
|
|
|
|
return -EACCES;
|
|
|
|
|
|
|
|
sp = smk_import(value, size);
|
|
|
|
if (sp == NULL)
|
|
|
|
return -EINVAL;
|
|
|
|
|
|
|
|
if (strcmp(name, XATTR_SMACK_SUFFIX) == 0) {
|
|
|
|
nsp->smk_inode = sp;
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
/*
|
|
|
|
* The rest of the Smack xattrs are only on sockets.
|
|
|
|
*/
|
|
|
|
if (inode->i_sb->s_magic != SOCKFS_MAGIC)
|
|
|
|
return -EOPNOTSUPP;
|
|
|
|
|
|
|
|
sock = SOCKET_I(inode);
|
2008-02-13 23:03:34 +00:00
|
|
|
if (sock == NULL || sock->sk == NULL)
|
Smack: Simplified Mandatory Access Control Kernel
Smack is the Simplified Mandatory Access Control Kernel.
Smack implements mandatory access control (MAC) using labels
attached to tasks and data containers, including files, SVIPC,
and other tasks. Smack is a kernel based scheme that requires
an absolute minimum of application support and a very small
amount of configuration data.
Smack uses extended attributes and
provides a set of general mount options, borrowing technics used
elsewhere. Smack uses netlabel for CIPSO labeling. Smack provides
a pseudo-filesystem smackfs that is used for manipulation of
system Smack attributes.
The patch, patches for ls and sshd, a README, a startup script,
and x86 binaries for ls and sshd are also available on
http://www.schaufler-ca.com
Development has been done using Fedora Core 7 in a virtual machine
environment and on an old Sony laptop.
Smack provides mandatory access controls based on the label attached
to a task and the label attached to the object it is attempting to
access. Smack labels are deliberately short (1-23 characters) text
strings. Single character labels using special characters are reserved
for system use. The only operation applied to Smack labels is equality
comparison. No wildcards or expressions, regular or otherwise, are
used. Smack labels are composed of printable characters and may not
include "/".
A file always gets the Smack label of the task that created it.
Smack defines and uses these labels:
"*" - pronounced "star"
"_" - pronounced "floor"
"^" - pronounced "hat"
"?" - pronounced "huh"
The access rules enforced by Smack are, in order:
1. Any access requested by a task labeled "*" is denied.
2. A read or execute access requested by a task labeled "^"
is permitted.
3. A read or execute access requested on an object labeled "_"
is permitted.
4. Any access requested on an object labeled "*" is permitted.
5. Any access requested by a task on an object with the same
label is permitted.
6. Any access requested that is explicitly defined in the loaded
rule set is permitted.
7. Any other access is denied.
Rules may be explicitly defined by writing subject,object,access
triples to /smack/load.
Smack rule sets can be easily defined that describe Bell&LaPadula
sensitivity, Biba integrity, and a variety of interesting
configurations. Smack rule sets can be modified on the fly to
accommodate changes in the operating environment or even the time
of day.
Some practical use cases:
Hierarchical levels. The less common of the two usual uses
for MLS systems is to define hierarchical levels, often
unclassified, confidential, secret, and so on. To set up smack
to support this, these rules could be defined:
C Unclass rx
S C rx
S Unclass rx
TS S rx
TS C rx
TS Unclass rx
A TS process can read S, C, and Unclass data, but cannot write it.
An S process can read C and Unclass. Note that specifying that
TS can read S and S can read C does not imply TS can read C, it
has to be explicitly stated.
Non-hierarchical categories. This is the more common of the
usual uses for an MLS system. Since the default rule is that a
subject cannot access an object with a different label no
access rules are required to implement compartmentalization.
A case that the Bell & LaPadula policy does not allow is demonstrated
with this Smack access rule:
A case that Bell&LaPadula does not allow that Smack does:
ESPN ABC r
ABC ESPN r
On my portable video device I have two applications, one that
shows ABC programming and the other ESPN programming. ESPN wants
to show me sport stories that show up as news, and ABC will
only provide minimal information about a sports story if ESPN
is covering it. Each side can look at the other's info, neither
can change the other. Neither can see what FOX is up to, which
is just as well all things considered.
Another case that I especially like:
SatData Guard w
Guard Publish w
A program running with the Guard label opens a UDP socket and
accepts messages sent by a program running with a SatData label.
The Guard program inspects the message to ensure it is wholesome
and if it is sends it to a program running with the Publish label.
This program then puts the information passed in an appropriate
place. Note that the Guard program cannot write to a Publish
file system object because file system semanitic require read as
well as write.
The four cases (categories, levels, mutual read, guardbox) here
are all quite real, and problems I've been asked to solve over
the years. The first two are easy to do with traditonal MLS systems
while the last two you can't without invoking privilege, at least
for a while.
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Cc: Joshua Brindle <method@manicmethod.com>
Cc: Paul Moore <paul.moore@hp.com>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: Chris Wright <chrisw@sous-sol.org>
Cc: James Morris <jmorris@namei.org>
Cc: "Ahmed S. Darwish" <darwish.07@gmail.com>
Cc: Andrew G. Morgan <morgan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-05 06:29:50 +00:00
|
|
|
return -EOPNOTSUPP;
|
|
|
|
|
|
|
|
ssp = sock->sk->sk_security;
|
|
|
|
|
|
|
|
if (strcmp(name, XATTR_SMACK_IPIN) == 0)
|
|
|
|
ssp->smk_in = sp;
|
|
|
|
else if (strcmp(name, XATTR_SMACK_IPOUT) == 0) {
|
|
|
|
ssp->smk_out = sp;
|
2008-02-15 23:24:25 +00:00
|
|
|
rc = smack_netlabel(sock->sk);
|
|
|
|
if (rc != 0)
|
|
|
|
printk(KERN_WARNING "Smack: \"%s\" netlbl error %d.\n",
|
|
|
|
__func__, -rc);
|
Smack: Simplified Mandatory Access Control Kernel
Smack is the Simplified Mandatory Access Control Kernel.
Smack implements mandatory access control (MAC) using labels
attached to tasks and data containers, including files, SVIPC,
and other tasks. Smack is a kernel based scheme that requires
an absolute minimum of application support and a very small
amount of configuration data.
Smack uses extended attributes and
provides a set of general mount options, borrowing technics used
elsewhere. Smack uses netlabel for CIPSO labeling. Smack provides
a pseudo-filesystem smackfs that is used for manipulation of
system Smack attributes.
The patch, patches for ls and sshd, a README, a startup script,
and x86 binaries for ls and sshd are also available on
http://www.schaufler-ca.com
Development has been done using Fedora Core 7 in a virtual machine
environment and on an old Sony laptop.
Smack provides mandatory access controls based on the label attached
to a task and the label attached to the object it is attempting to
access. Smack labels are deliberately short (1-23 characters) text
strings. Single character labels using special characters are reserved
for system use. The only operation applied to Smack labels is equality
comparison. No wildcards or expressions, regular or otherwise, are
used. Smack labels are composed of printable characters and may not
include "/".
A file always gets the Smack label of the task that created it.
Smack defines and uses these labels:
"*" - pronounced "star"
"_" - pronounced "floor"
"^" - pronounced "hat"
"?" - pronounced "huh"
The access rules enforced by Smack are, in order:
1. Any access requested by a task labeled "*" is denied.
2. A read or execute access requested by a task labeled "^"
is permitted.
3. A read or execute access requested on an object labeled "_"
is permitted.
4. Any access requested on an object labeled "*" is permitted.
5. Any access requested by a task on an object with the same
label is permitted.
6. Any access requested that is explicitly defined in the loaded
rule set is permitted.
7. Any other access is denied.
Rules may be explicitly defined by writing subject,object,access
triples to /smack/load.
Smack rule sets can be easily defined that describe Bell&LaPadula
sensitivity, Biba integrity, and a variety of interesting
configurations. Smack rule sets can be modified on the fly to
accommodate changes in the operating environment or even the time
of day.
Some practical use cases:
Hierarchical levels. The less common of the two usual uses
for MLS systems is to define hierarchical levels, often
unclassified, confidential, secret, and so on. To set up smack
to support this, these rules could be defined:
C Unclass rx
S C rx
S Unclass rx
TS S rx
TS C rx
TS Unclass rx
A TS process can read S, C, and Unclass data, but cannot write it.
An S process can read C and Unclass. Note that specifying that
TS can read S and S can read C does not imply TS can read C, it
has to be explicitly stated.
Non-hierarchical categories. This is the more common of the
usual uses for an MLS system. Since the default rule is that a
subject cannot access an object with a different label no
access rules are required to implement compartmentalization.
A case that the Bell & LaPadula policy does not allow is demonstrated
with this Smack access rule:
A case that Bell&LaPadula does not allow that Smack does:
ESPN ABC r
ABC ESPN r
On my portable video device I have two applications, one that
shows ABC programming and the other ESPN programming. ESPN wants
to show me sport stories that show up as news, and ABC will
only provide minimal information about a sports story if ESPN
is covering it. Each side can look at the other's info, neither
can change the other. Neither can see what FOX is up to, which
is just as well all things considered.
Another case that I especially like:
SatData Guard w
Guard Publish w
A program running with the Guard label opens a UDP socket and
accepts messages sent by a program running with a SatData label.
The Guard program inspects the message to ensure it is wholesome
and if it is sends it to a program running with the Publish label.
This program then puts the information passed in an appropriate
place. Note that the Guard program cannot write to a Publish
file system object because file system semanitic require read as
well as write.
The four cases (categories, levels, mutual read, guardbox) here
are all quite real, and problems I've been asked to solve over
the years. The first two are easy to do with traditonal MLS systems
while the last two you can't without invoking privilege, at least
for a while.
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Cc: Joshua Brindle <method@manicmethod.com>
Cc: Paul Moore <paul.moore@hp.com>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: Chris Wright <chrisw@sous-sol.org>
Cc: James Morris <jmorris@namei.org>
Cc: "Ahmed S. Darwish" <darwish.07@gmail.com>
Cc: Andrew G. Morgan <morgan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-05 06:29:50 +00:00
|
|
|
} else
|
|
|
|
return -EOPNOTSUPP;
|
|
|
|
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_socket_post_create - finish socket setup
|
|
|
|
* @sock: the socket
|
|
|
|
* @family: protocol family
|
|
|
|
* @type: unused
|
|
|
|
* @protocol: unused
|
|
|
|
* @kern: unused
|
|
|
|
*
|
|
|
|
* Sets the netlabel information on the socket
|
|
|
|
*
|
|
|
|
* Returns 0 on success, and error code otherwise
|
|
|
|
*/
|
|
|
|
static int smack_socket_post_create(struct socket *sock, int family,
|
|
|
|
int type, int protocol, int kern)
|
|
|
|
{
|
2008-02-13 23:03:34 +00:00
|
|
|
if (family != PF_INET || sock->sk == NULL)
|
Smack: Simplified Mandatory Access Control Kernel
Smack is the Simplified Mandatory Access Control Kernel.
Smack implements mandatory access control (MAC) using labels
attached to tasks and data containers, including files, SVIPC,
and other tasks. Smack is a kernel based scheme that requires
an absolute minimum of application support and a very small
amount of configuration data.
Smack uses extended attributes and
provides a set of general mount options, borrowing technics used
elsewhere. Smack uses netlabel for CIPSO labeling. Smack provides
a pseudo-filesystem smackfs that is used for manipulation of
system Smack attributes.
The patch, patches for ls and sshd, a README, a startup script,
and x86 binaries for ls and sshd are also available on
http://www.schaufler-ca.com
Development has been done using Fedora Core 7 in a virtual machine
environment and on an old Sony laptop.
Smack provides mandatory access controls based on the label attached
to a task and the label attached to the object it is attempting to
access. Smack labels are deliberately short (1-23 characters) text
strings. Single character labels using special characters are reserved
for system use. The only operation applied to Smack labels is equality
comparison. No wildcards or expressions, regular or otherwise, are
used. Smack labels are composed of printable characters and may not
include "/".
A file always gets the Smack label of the task that created it.
Smack defines and uses these labels:
"*" - pronounced "star"
"_" - pronounced "floor"
"^" - pronounced "hat"
"?" - pronounced "huh"
The access rules enforced by Smack are, in order:
1. Any access requested by a task labeled "*" is denied.
2. A read or execute access requested by a task labeled "^"
is permitted.
3. A read or execute access requested on an object labeled "_"
is permitted.
4. Any access requested on an object labeled "*" is permitted.
5. Any access requested by a task on an object with the same
label is permitted.
6. Any access requested that is explicitly defined in the loaded
rule set is permitted.
7. Any other access is denied.
Rules may be explicitly defined by writing subject,object,access
triples to /smack/load.
Smack rule sets can be easily defined that describe Bell&LaPadula
sensitivity, Biba integrity, and a variety of interesting
configurations. Smack rule sets can be modified on the fly to
accommodate changes in the operating environment or even the time
of day.
Some practical use cases:
Hierarchical levels. The less common of the two usual uses
for MLS systems is to define hierarchical levels, often
unclassified, confidential, secret, and so on. To set up smack
to support this, these rules could be defined:
C Unclass rx
S C rx
S Unclass rx
TS S rx
TS C rx
TS Unclass rx
A TS process can read S, C, and Unclass data, but cannot write it.
An S process can read C and Unclass. Note that specifying that
TS can read S and S can read C does not imply TS can read C, it
has to be explicitly stated.
Non-hierarchical categories. This is the more common of the
usual uses for an MLS system. Since the default rule is that a
subject cannot access an object with a different label no
access rules are required to implement compartmentalization.
A case that the Bell & LaPadula policy does not allow is demonstrated
with this Smack access rule:
A case that Bell&LaPadula does not allow that Smack does:
ESPN ABC r
ABC ESPN r
On my portable video device I have two applications, one that
shows ABC programming and the other ESPN programming. ESPN wants
to show me sport stories that show up as news, and ABC will
only provide minimal information about a sports story if ESPN
is covering it. Each side can look at the other's info, neither
can change the other. Neither can see what FOX is up to, which
is just as well all things considered.
Another case that I especially like:
SatData Guard w
Guard Publish w
A program running with the Guard label opens a UDP socket and
accepts messages sent by a program running with a SatData label.
The Guard program inspects the message to ensure it is wholesome
and if it is sends it to a program running with the Publish label.
This program then puts the information passed in an appropriate
place. Note that the Guard program cannot write to a Publish
file system object because file system semanitic require read as
well as write.
The four cases (categories, levels, mutual read, guardbox) here
are all quite real, and problems I've been asked to solve over
the years. The first two are easy to do with traditonal MLS systems
while the last two you can't without invoking privilege, at least
for a while.
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Cc: Joshua Brindle <method@manicmethod.com>
Cc: Paul Moore <paul.moore@hp.com>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: Chris Wright <chrisw@sous-sol.org>
Cc: James Morris <jmorris@namei.org>
Cc: "Ahmed S. Darwish" <darwish.07@gmail.com>
Cc: Andrew G. Morgan <morgan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-05 06:29:50 +00:00
|
|
|
return 0;
|
|
|
|
/*
|
|
|
|
* Set the outbound netlbl.
|
|
|
|
*/
|
|
|
|
return smack_netlabel(sock->sk);
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_flags_to_may - convert S_ to MAY_ values
|
|
|
|
* @flags: the S_ value
|
|
|
|
*
|
|
|
|
* Returns the equivalent MAY_ value
|
|
|
|
*/
|
|
|
|
static int smack_flags_to_may(int flags)
|
|
|
|
{
|
|
|
|
int may = 0;
|
|
|
|
|
|
|
|
if (flags & S_IRUGO)
|
|
|
|
may |= MAY_READ;
|
|
|
|
if (flags & S_IWUGO)
|
|
|
|
may |= MAY_WRITE;
|
|
|
|
if (flags & S_IXUGO)
|
|
|
|
may |= MAY_EXEC;
|
|
|
|
|
|
|
|
return may;
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_msg_msg_alloc_security - Set the security blob for msg_msg
|
|
|
|
* @msg: the object
|
|
|
|
*
|
|
|
|
* Returns 0
|
|
|
|
*/
|
|
|
|
static int smack_msg_msg_alloc_security(struct msg_msg *msg)
|
|
|
|
{
|
|
|
|
msg->security = current->security;
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_msg_msg_free_security - Clear the security blob for msg_msg
|
|
|
|
* @msg: the object
|
|
|
|
*
|
|
|
|
* Clears the blob pointer
|
|
|
|
*/
|
|
|
|
static void smack_msg_msg_free_security(struct msg_msg *msg)
|
|
|
|
{
|
|
|
|
msg->security = NULL;
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_of_shm - the smack pointer for the shm
|
|
|
|
* @shp: the object
|
|
|
|
*
|
|
|
|
* Returns a pointer to the smack value
|
|
|
|
*/
|
|
|
|
static char *smack_of_shm(struct shmid_kernel *shp)
|
|
|
|
{
|
|
|
|
return (char *)shp->shm_perm.security;
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_shm_alloc_security - Set the security blob for shm
|
|
|
|
* @shp: the object
|
|
|
|
*
|
|
|
|
* Returns 0
|
|
|
|
*/
|
|
|
|
static int smack_shm_alloc_security(struct shmid_kernel *shp)
|
|
|
|
{
|
|
|
|
struct kern_ipc_perm *isp = &shp->shm_perm;
|
|
|
|
|
|
|
|
isp->security = current->security;
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_shm_free_security - Clear the security blob for shm
|
|
|
|
* @shp: the object
|
|
|
|
*
|
|
|
|
* Clears the blob pointer
|
|
|
|
*/
|
|
|
|
static void smack_shm_free_security(struct shmid_kernel *shp)
|
|
|
|
{
|
|
|
|
struct kern_ipc_perm *isp = &shp->shm_perm;
|
|
|
|
|
|
|
|
isp->security = NULL;
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_shm_associate - Smack access check for shm
|
|
|
|
* @shp: the object
|
|
|
|
* @shmflg: access requested
|
|
|
|
*
|
|
|
|
* Returns 0 if current has the requested access, error code otherwise
|
|
|
|
*/
|
|
|
|
static int smack_shm_associate(struct shmid_kernel *shp, int shmflg)
|
|
|
|
{
|
|
|
|
char *ssp = smack_of_shm(shp);
|
|
|
|
int may;
|
|
|
|
|
|
|
|
may = smack_flags_to_may(shmflg);
|
|
|
|
return smk_curacc(ssp, may);
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_shm_shmctl - Smack access check for shm
|
|
|
|
* @shp: the object
|
|
|
|
* @cmd: what it wants to do
|
|
|
|
*
|
|
|
|
* Returns 0 if current has the requested access, error code otherwise
|
|
|
|
*/
|
|
|
|
static int smack_shm_shmctl(struct shmid_kernel *shp, int cmd)
|
|
|
|
{
|
|
|
|
char *ssp = smack_of_shm(shp);
|
|
|
|
int may;
|
|
|
|
|
|
|
|
switch (cmd) {
|
|
|
|
case IPC_STAT:
|
|
|
|
case SHM_STAT:
|
|
|
|
may = MAY_READ;
|
|
|
|
break;
|
|
|
|
case IPC_SET:
|
|
|
|
case SHM_LOCK:
|
|
|
|
case SHM_UNLOCK:
|
|
|
|
case IPC_RMID:
|
|
|
|
may = MAY_READWRITE;
|
|
|
|
break;
|
|
|
|
case IPC_INFO:
|
|
|
|
case SHM_INFO:
|
|
|
|
/*
|
|
|
|
* System level information.
|
|
|
|
*/
|
|
|
|
return 0;
|
|
|
|
default:
|
|
|
|
return -EINVAL;
|
|
|
|
}
|
|
|
|
|
|
|
|
return smk_curacc(ssp, may);
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_shm_shmat - Smack access for shmat
|
|
|
|
* @shp: the object
|
|
|
|
* @shmaddr: unused
|
|
|
|
* @shmflg: access requested
|
|
|
|
*
|
|
|
|
* Returns 0 if current has the requested access, error code otherwise
|
|
|
|
*/
|
|
|
|
static int smack_shm_shmat(struct shmid_kernel *shp, char __user *shmaddr,
|
|
|
|
int shmflg)
|
|
|
|
{
|
|
|
|
char *ssp = smack_of_shm(shp);
|
|
|
|
int may;
|
|
|
|
|
|
|
|
may = smack_flags_to_may(shmflg);
|
|
|
|
return smk_curacc(ssp, may);
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_of_sem - the smack pointer for the sem
|
|
|
|
* @sma: the object
|
|
|
|
*
|
|
|
|
* Returns a pointer to the smack value
|
|
|
|
*/
|
|
|
|
static char *smack_of_sem(struct sem_array *sma)
|
|
|
|
{
|
|
|
|
return (char *)sma->sem_perm.security;
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_sem_alloc_security - Set the security blob for sem
|
|
|
|
* @sma: the object
|
|
|
|
*
|
|
|
|
* Returns 0
|
|
|
|
*/
|
|
|
|
static int smack_sem_alloc_security(struct sem_array *sma)
|
|
|
|
{
|
|
|
|
struct kern_ipc_perm *isp = &sma->sem_perm;
|
|
|
|
|
|
|
|
isp->security = current->security;
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_sem_free_security - Clear the security blob for sem
|
|
|
|
* @sma: the object
|
|
|
|
*
|
|
|
|
* Clears the blob pointer
|
|
|
|
*/
|
|
|
|
static void smack_sem_free_security(struct sem_array *sma)
|
|
|
|
{
|
|
|
|
struct kern_ipc_perm *isp = &sma->sem_perm;
|
|
|
|
|
|
|
|
isp->security = NULL;
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_sem_associate - Smack access check for sem
|
|
|
|
* @sma: the object
|
|
|
|
* @semflg: access requested
|
|
|
|
*
|
|
|
|
* Returns 0 if current has the requested access, error code otherwise
|
|
|
|
*/
|
|
|
|
static int smack_sem_associate(struct sem_array *sma, int semflg)
|
|
|
|
{
|
|
|
|
char *ssp = smack_of_sem(sma);
|
|
|
|
int may;
|
|
|
|
|
|
|
|
may = smack_flags_to_may(semflg);
|
|
|
|
return smk_curacc(ssp, may);
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_sem_shmctl - Smack access check for sem
|
|
|
|
* @sma: the object
|
|
|
|
* @cmd: what it wants to do
|
|
|
|
*
|
|
|
|
* Returns 0 if current has the requested access, error code otherwise
|
|
|
|
*/
|
|
|
|
static int smack_sem_semctl(struct sem_array *sma, int cmd)
|
|
|
|
{
|
|
|
|
char *ssp = smack_of_sem(sma);
|
|
|
|
int may;
|
|
|
|
|
|
|
|
switch (cmd) {
|
|
|
|
case GETPID:
|
|
|
|
case GETNCNT:
|
|
|
|
case GETZCNT:
|
|
|
|
case GETVAL:
|
|
|
|
case GETALL:
|
|
|
|
case IPC_STAT:
|
|
|
|
case SEM_STAT:
|
|
|
|
may = MAY_READ;
|
|
|
|
break;
|
|
|
|
case SETVAL:
|
|
|
|
case SETALL:
|
|
|
|
case IPC_RMID:
|
|
|
|
case IPC_SET:
|
|
|
|
may = MAY_READWRITE;
|
|
|
|
break;
|
|
|
|
case IPC_INFO:
|
|
|
|
case SEM_INFO:
|
|
|
|
/*
|
|
|
|
* System level information
|
|
|
|
*/
|
|
|
|
return 0;
|
|
|
|
default:
|
|
|
|
return -EINVAL;
|
|
|
|
}
|
|
|
|
|
|
|
|
return smk_curacc(ssp, may);
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_sem_semop - Smack checks of semaphore operations
|
|
|
|
* @sma: the object
|
|
|
|
* @sops: unused
|
|
|
|
* @nsops: unused
|
|
|
|
* @alter: unused
|
|
|
|
*
|
|
|
|
* Treated as read and write in all cases.
|
|
|
|
*
|
|
|
|
* Returns 0 if access is allowed, error code otherwise
|
|
|
|
*/
|
|
|
|
static int smack_sem_semop(struct sem_array *sma, struct sembuf *sops,
|
|
|
|
unsigned nsops, int alter)
|
|
|
|
{
|
|
|
|
char *ssp = smack_of_sem(sma);
|
|
|
|
|
|
|
|
return smk_curacc(ssp, MAY_READWRITE);
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_msg_alloc_security - Set the security blob for msg
|
|
|
|
* @msq: the object
|
|
|
|
*
|
|
|
|
* Returns 0
|
|
|
|
*/
|
|
|
|
static int smack_msg_queue_alloc_security(struct msg_queue *msq)
|
|
|
|
{
|
|
|
|
struct kern_ipc_perm *kisp = &msq->q_perm;
|
|
|
|
|
|
|
|
kisp->security = current->security;
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_msg_free_security - Clear the security blob for msg
|
|
|
|
* @msq: the object
|
|
|
|
*
|
|
|
|
* Clears the blob pointer
|
|
|
|
*/
|
|
|
|
static void smack_msg_queue_free_security(struct msg_queue *msq)
|
|
|
|
{
|
|
|
|
struct kern_ipc_perm *kisp = &msq->q_perm;
|
|
|
|
|
|
|
|
kisp->security = NULL;
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_of_msq - the smack pointer for the msq
|
|
|
|
* @msq: the object
|
|
|
|
*
|
|
|
|
* Returns a pointer to the smack value
|
|
|
|
*/
|
|
|
|
static char *smack_of_msq(struct msg_queue *msq)
|
|
|
|
{
|
|
|
|
return (char *)msq->q_perm.security;
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_msg_queue_associate - Smack access check for msg_queue
|
|
|
|
* @msq: the object
|
|
|
|
* @msqflg: access requested
|
|
|
|
*
|
|
|
|
* Returns 0 if current has the requested access, error code otherwise
|
|
|
|
*/
|
|
|
|
static int smack_msg_queue_associate(struct msg_queue *msq, int msqflg)
|
|
|
|
{
|
|
|
|
char *msp = smack_of_msq(msq);
|
|
|
|
int may;
|
|
|
|
|
|
|
|
may = smack_flags_to_may(msqflg);
|
|
|
|
return smk_curacc(msp, may);
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_msg_queue_msgctl - Smack access check for msg_queue
|
|
|
|
* @msq: the object
|
|
|
|
* @cmd: what it wants to do
|
|
|
|
*
|
|
|
|
* Returns 0 if current has the requested access, error code otherwise
|
|
|
|
*/
|
|
|
|
static int smack_msg_queue_msgctl(struct msg_queue *msq, int cmd)
|
|
|
|
{
|
|
|
|
char *msp = smack_of_msq(msq);
|
|
|
|
int may;
|
|
|
|
|
|
|
|
switch (cmd) {
|
|
|
|
case IPC_STAT:
|
|
|
|
case MSG_STAT:
|
|
|
|
may = MAY_READ;
|
|
|
|
break;
|
|
|
|
case IPC_SET:
|
|
|
|
case IPC_RMID:
|
|
|
|
may = MAY_READWRITE;
|
|
|
|
break;
|
|
|
|
case IPC_INFO:
|
|
|
|
case MSG_INFO:
|
|
|
|
/*
|
|
|
|
* System level information
|
|
|
|
*/
|
|
|
|
return 0;
|
|
|
|
default:
|
|
|
|
return -EINVAL;
|
|
|
|
}
|
|
|
|
|
|
|
|
return smk_curacc(msp, may);
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_msg_queue_msgsnd - Smack access check for msg_queue
|
|
|
|
* @msq: the object
|
|
|
|
* @msg: unused
|
|
|
|
* @msqflg: access requested
|
|
|
|
*
|
|
|
|
* Returns 0 if current has the requested access, error code otherwise
|
|
|
|
*/
|
|
|
|
static int smack_msg_queue_msgsnd(struct msg_queue *msq, struct msg_msg *msg,
|
|
|
|
int msqflg)
|
|
|
|
{
|
|
|
|
char *msp = smack_of_msq(msq);
|
|
|
|
int rc;
|
|
|
|
|
|
|
|
rc = smack_flags_to_may(msqflg);
|
|
|
|
return smk_curacc(msp, rc);
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_msg_queue_msgsnd - Smack access check for msg_queue
|
|
|
|
* @msq: the object
|
|
|
|
* @msg: unused
|
|
|
|
* @target: unused
|
|
|
|
* @type: unused
|
|
|
|
* @mode: unused
|
|
|
|
*
|
|
|
|
* Returns 0 if current has read and write access, error code otherwise
|
|
|
|
*/
|
|
|
|
static int smack_msg_queue_msgrcv(struct msg_queue *msq, struct msg_msg *msg,
|
|
|
|
struct task_struct *target, long type, int mode)
|
|
|
|
{
|
|
|
|
char *msp = smack_of_msq(msq);
|
|
|
|
|
|
|
|
return smk_curacc(msp, MAY_READWRITE);
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_ipc_permission - Smack access for ipc_permission()
|
|
|
|
* @ipp: the object permissions
|
|
|
|
* @flag: access requested
|
|
|
|
*
|
|
|
|
* Returns 0 if current has read and write access, error code otherwise
|
|
|
|
*/
|
|
|
|
static int smack_ipc_permission(struct kern_ipc_perm *ipp, short flag)
|
|
|
|
{
|
|
|
|
char *isp = ipp->security;
|
|
|
|
int may;
|
|
|
|
|
|
|
|
may = smack_flags_to_may(flag);
|
|
|
|
return smk_curacc(isp, may);
|
|
|
|
}
|
|
|
|
|
2008-02-23 23:24:04 +00:00
|
|
|
/* module stacking operations */
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_register_security - stack capability module
|
|
|
|
* @name: module name
|
|
|
|
* @ops: module operations - ignored
|
|
|
|
*
|
|
|
|
* Allow the capability module to register.
|
|
|
|
*/
|
|
|
|
static int smack_register_security(const char *name,
|
|
|
|
struct security_operations *ops)
|
|
|
|
{
|
|
|
|
if (strcmp(name, "capability") != 0)
|
|
|
|
return -EINVAL;
|
|
|
|
|
|
|
|
printk(KERN_INFO "%s: Registering secondary module %s\n",
|
|
|
|
__func__, name);
|
|
|
|
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
Smack: Simplified Mandatory Access Control Kernel
Smack is the Simplified Mandatory Access Control Kernel.
Smack implements mandatory access control (MAC) using labels
attached to tasks and data containers, including files, SVIPC,
and other tasks. Smack is a kernel based scheme that requires
an absolute minimum of application support and a very small
amount of configuration data.
Smack uses extended attributes and
provides a set of general mount options, borrowing technics used
elsewhere. Smack uses netlabel for CIPSO labeling. Smack provides
a pseudo-filesystem smackfs that is used for manipulation of
system Smack attributes.
The patch, patches for ls and sshd, a README, a startup script,
and x86 binaries for ls and sshd are also available on
http://www.schaufler-ca.com
Development has been done using Fedora Core 7 in a virtual machine
environment and on an old Sony laptop.
Smack provides mandatory access controls based on the label attached
to a task and the label attached to the object it is attempting to
access. Smack labels are deliberately short (1-23 characters) text
strings. Single character labels using special characters are reserved
for system use. The only operation applied to Smack labels is equality
comparison. No wildcards or expressions, regular or otherwise, are
used. Smack labels are composed of printable characters and may not
include "/".
A file always gets the Smack label of the task that created it.
Smack defines and uses these labels:
"*" - pronounced "star"
"_" - pronounced "floor"
"^" - pronounced "hat"
"?" - pronounced "huh"
The access rules enforced by Smack are, in order:
1. Any access requested by a task labeled "*" is denied.
2. A read or execute access requested by a task labeled "^"
is permitted.
3. A read or execute access requested on an object labeled "_"
is permitted.
4. Any access requested on an object labeled "*" is permitted.
5. Any access requested by a task on an object with the same
label is permitted.
6. Any access requested that is explicitly defined in the loaded
rule set is permitted.
7. Any other access is denied.
Rules may be explicitly defined by writing subject,object,access
triples to /smack/load.
Smack rule sets can be easily defined that describe Bell&LaPadula
sensitivity, Biba integrity, and a variety of interesting
configurations. Smack rule sets can be modified on the fly to
accommodate changes in the operating environment or even the time
of day.
Some practical use cases:
Hierarchical levels. The less common of the two usual uses
for MLS systems is to define hierarchical levels, often
unclassified, confidential, secret, and so on. To set up smack
to support this, these rules could be defined:
C Unclass rx
S C rx
S Unclass rx
TS S rx
TS C rx
TS Unclass rx
A TS process can read S, C, and Unclass data, but cannot write it.
An S process can read C and Unclass. Note that specifying that
TS can read S and S can read C does not imply TS can read C, it
has to be explicitly stated.
Non-hierarchical categories. This is the more common of the
usual uses for an MLS system. Since the default rule is that a
subject cannot access an object with a different label no
access rules are required to implement compartmentalization.
A case that the Bell & LaPadula policy does not allow is demonstrated
with this Smack access rule:
A case that Bell&LaPadula does not allow that Smack does:
ESPN ABC r
ABC ESPN r
On my portable video device I have two applications, one that
shows ABC programming and the other ESPN programming. ESPN wants
to show me sport stories that show up as news, and ABC will
only provide minimal information about a sports story if ESPN
is covering it. Each side can look at the other's info, neither
can change the other. Neither can see what FOX is up to, which
is just as well all things considered.
Another case that I especially like:
SatData Guard w
Guard Publish w
A program running with the Guard label opens a UDP socket and
accepts messages sent by a program running with a SatData label.
The Guard program inspects the message to ensure it is wholesome
and if it is sends it to a program running with the Publish label.
This program then puts the information passed in an appropriate
place. Note that the Guard program cannot write to a Publish
file system object because file system semanitic require read as
well as write.
The four cases (categories, levels, mutual read, guardbox) here
are all quite real, and problems I've been asked to solve over
the years. The first two are easy to do with traditonal MLS systems
while the last two you can't without invoking privilege, at least
for a while.
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Cc: Joshua Brindle <method@manicmethod.com>
Cc: Paul Moore <paul.moore@hp.com>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: Chris Wright <chrisw@sous-sol.org>
Cc: James Morris <jmorris@namei.org>
Cc: "Ahmed S. Darwish" <darwish.07@gmail.com>
Cc: Andrew G. Morgan <morgan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-05 06:29:50 +00:00
|
|
|
/**
|
|
|
|
* smack_d_instantiate - Make sure the blob is correct on an inode
|
|
|
|
* @opt_dentry: unused
|
|
|
|
* @inode: the object
|
|
|
|
*
|
|
|
|
* Set the inode's security blob if it hasn't been done already.
|
|
|
|
*/
|
|
|
|
static void smack_d_instantiate(struct dentry *opt_dentry, struct inode *inode)
|
|
|
|
{
|
|
|
|
struct super_block *sbp;
|
|
|
|
struct superblock_smack *sbsp;
|
|
|
|
struct inode_smack *isp;
|
|
|
|
char *csp = current->security;
|
|
|
|
char *fetched;
|
|
|
|
char *final;
|
|
|
|
struct dentry *dp;
|
|
|
|
|
|
|
|
if (inode == NULL)
|
|
|
|
return;
|
|
|
|
|
|
|
|
isp = inode->i_security;
|
|
|
|
|
|
|
|
mutex_lock(&isp->smk_lock);
|
|
|
|
/*
|
|
|
|
* If the inode is already instantiated
|
|
|
|
* take the quick way out
|
|
|
|
*/
|
|
|
|
if (isp->smk_flags & SMK_INODE_INSTANT)
|
|
|
|
goto unlockandout;
|
|
|
|
|
|
|
|
sbp = inode->i_sb;
|
|
|
|
sbsp = sbp->s_security;
|
|
|
|
/*
|
|
|
|
* We're going to use the superblock default label
|
|
|
|
* if there's no label on the file.
|
|
|
|
*/
|
|
|
|
final = sbsp->smk_default;
|
|
|
|
|
|
|
|
/*
|
|
|
|
* This is pretty hackish.
|
|
|
|
* Casey says that we shouldn't have to do
|
|
|
|
* file system specific code, but it does help
|
|
|
|
* with keeping it simple.
|
|
|
|
*/
|
|
|
|
switch (sbp->s_magic) {
|
|
|
|
case SMACK_MAGIC:
|
|
|
|
/*
|
|
|
|
* Casey says that it's a little embarassing
|
|
|
|
* that the smack file system doesn't do
|
|
|
|
* extended attributes.
|
|
|
|
*/
|
|
|
|
final = smack_known_star.smk_known;
|
|
|
|
break;
|
|
|
|
case PIPEFS_MAGIC:
|
|
|
|
/*
|
|
|
|
* Casey says pipes are easy (?)
|
|
|
|
*/
|
|
|
|
final = smack_known_star.smk_known;
|
|
|
|
break;
|
|
|
|
case DEVPTS_SUPER_MAGIC:
|
|
|
|
/*
|
|
|
|
* devpts seems content with the label of the task.
|
|
|
|
* Programs that change smack have to treat the
|
|
|
|
* pty with respect.
|
|
|
|
*/
|
|
|
|
final = csp;
|
|
|
|
break;
|
|
|
|
case SOCKFS_MAGIC:
|
|
|
|
/*
|
|
|
|
* Casey says sockets get the smack of the task.
|
|
|
|
*/
|
|
|
|
final = csp;
|
|
|
|
break;
|
|
|
|
case PROC_SUPER_MAGIC:
|
|
|
|
/*
|
|
|
|
* Casey says procfs appears not to care.
|
|
|
|
* The superblock default suffices.
|
|
|
|
*/
|
|
|
|
break;
|
|
|
|
case TMPFS_MAGIC:
|
|
|
|
/*
|
|
|
|
* Device labels should come from the filesystem,
|
|
|
|
* but watch out, because they're volitile,
|
|
|
|
* getting recreated on every reboot.
|
|
|
|
*/
|
|
|
|
final = smack_known_star.smk_known;
|
|
|
|
/*
|
|
|
|
* No break.
|
|
|
|
*
|
|
|
|
* If a smack value has been set we want to use it,
|
|
|
|
* but since tmpfs isn't giving us the opportunity
|
|
|
|
* to set mount options simulate setting the
|
|
|
|
* superblock default.
|
|
|
|
*/
|
|
|
|
default:
|
|
|
|
/*
|
|
|
|
* This isn't an understood special case.
|
|
|
|
* Get the value from the xattr.
|
|
|
|
*
|
|
|
|
* No xattr support means, alas, no SMACK label.
|
|
|
|
* Use the aforeapplied default.
|
|
|
|
* It would be curious if the label of the task
|
|
|
|
* does not match that assigned.
|
|
|
|
*/
|
|
|
|
if (inode->i_op->getxattr == NULL)
|
|
|
|
break;
|
|
|
|
/*
|
|
|
|
* Get the dentry for xattr.
|
|
|
|
*/
|
|
|
|
if (opt_dentry == NULL) {
|
|
|
|
dp = d_find_alias(inode);
|
|
|
|
if (dp == NULL)
|
|
|
|
break;
|
|
|
|
} else {
|
|
|
|
dp = dget(opt_dentry);
|
|
|
|
if (dp == NULL)
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
|
|
|
|
fetched = smk_fetch(inode, dp);
|
|
|
|
if (fetched != NULL)
|
|
|
|
final = fetched;
|
|
|
|
|
|
|
|
dput(dp);
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
|
|
|
|
if (final == NULL)
|
|
|
|
isp->smk_inode = csp;
|
|
|
|
else
|
|
|
|
isp->smk_inode = final;
|
|
|
|
|
|
|
|
isp->smk_flags |= SMK_INODE_INSTANT;
|
|
|
|
|
|
|
|
unlockandout:
|
|
|
|
mutex_unlock(&isp->smk_lock);
|
|
|
|
return;
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_getprocattr - Smack process attribute access
|
|
|
|
* @p: the object task
|
|
|
|
* @name: the name of the attribute in /proc/.../attr
|
|
|
|
* @value: where to put the result
|
|
|
|
*
|
|
|
|
* Places a copy of the task Smack into value
|
|
|
|
*
|
|
|
|
* Returns the length of the smack label or an error code
|
|
|
|
*/
|
|
|
|
static int smack_getprocattr(struct task_struct *p, char *name, char **value)
|
|
|
|
{
|
|
|
|
char *cp;
|
|
|
|
int slen;
|
|
|
|
|
|
|
|
if (strcmp(name, "current") != 0)
|
|
|
|
return -EINVAL;
|
|
|
|
|
|
|
|
cp = kstrdup(p->security, GFP_KERNEL);
|
|
|
|
if (cp == NULL)
|
|
|
|
return -ENOMEM;
|
|
|
|
|
|
|
|
slen = strlen(cp);
|
|
|
|
*value = cp;
|
|
|
|
return slen;
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_setprocattr - Smack process attribute setting
|
|
|
|
* @p: the object task
|
|
|
|
* @name: the name of the attribute in /proc/.../attr
|
|
|
|
* @value: the value to set
|
|
|
|
* @size: the size of the value
|
|
|
|
*
|
|
|
|
* Sets the Smack value of the task. Only setting self
|
|
|
|
* is permitted and only with privilege
|
|
|
|
*
|
|
|
|
* Returns the length of the smack label or an error code
|
|
|
|
*/
|
|
|
|
static int smack_setprocattr(struct task_struct *p, char *name,
|
|
|
|
void *value, size_t size)
|
|
|
|
{
|
|
|
|
char *newsmack;
|
|
|
|
|
|
|
|
if (!__capable(p, CAP_MAC_ADMIN))
|
|
|
|
return -EPERM;
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Changing another process' Smack value is too dangerous
|
|
|
|
* and supports no sane use case.
|
|
|
|
*/
|
|
|
|
if (p != current)
|
|
|
|
return -EPERM;
|
|
|
|
|
|
|
|
if (value == NULL || size == 0 || size >= SMK_LABELLEN)
|
|
|
|
return -EINVAL;
|
|
|
|
|
|
|
|
if (strcmp(name, "current") != 0)
|
|
|
|
return -EINVAL;
|
|
|
|
|
|
|
|
newsmack = smk_import(value, size);
|
|
|
|
if (newsmack == NULL)
|
|
|
|
return -EINVAL;
|
|
|
|
|
|
|
|
p->security = newsmack;
|
|
|
|
return size;
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_unix_stream_connect - Smack access on UDS
|
|
|
|
* @sock: one socket
|
|
|
|
* @other: the other socket
|
|
|
|
* @newsk: unused
|
|
|
|
*
|
|
|
|
* Return 0 if a subject with the smack of sock could access
|
|
|
|
* an object with the smack of other, otherwise an error code
|
|
|
|
*/
|
|
|
|
static int smack_unix_stream_connect(struct socket *sock,
|
|
|
|
struct socket *other, struct sock *newsk)
|
|
|
|
{
|
|
|
|
struct inode *sp = SOCK_INODE(sock);
|
|
|
|
struct inode *op = SOCK_INODE(other);
|
|
|
|
|
|
|
|
return smk_access(smk_of_inode(sp), smk_of_inode(op), MAY_READWRITE);
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_unix_may_send - Smack access on UDS
|
|
|
|
* @sock: one socket
|
|
|
|
* @other: the other socket
|
|
|
|
*
|
|
|
|
* Return 0 if a subject with the smack of sock could access
|
|
|
|
* an object with the smack of other, otherwise an error code
|
|
|
|
*/
|
|
|
|
static int smack_unix_may_send(struct socket *sock, struct socket *other)
|
|
|
|
{
|
|
|
|
struct inode *sp = SOCK_INODE(sock);
|
|
|
|
struct inode *op = SOCK_INODE(other);
|
|
|
|
|
|
|
|
return smk_access(smk_of_inode(sp), smk_of_inode(op), MAY_WRITE);
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_from_secattr - Convert a netlabel attr.mls.lvl/attr.mls.cat
|
|
|
|
* pair to smack
|
|
|
|
* @sap: netlabel secattr
|
|
|
|
* @sip: where to put the result
|
|
|
|
*
|
|
|
|
* Copies a smack label into sip
|
|
|
|
*/
|
|
|
|
static void smack_from_secattr(struct netlbl_lsm_secattr *sap, char *sip)
|
|
|
|
{
|
|
|
|
char smack[SMK_LABELLEN];
|
|
|
|
int pcat;
|
|
|
|
|
|
|
|
if ((sap->flags & NETLBL_SECATTR_MLS_LVL) == 0) {
|
|
|
|
/*
|
|
|
|
* If there are flags but no level netlabel isn't
|
|
|
|
* behaving the way we expect it to.
|
|
|
|
*
|
|
|
|
* Without guidance regarding the smack value
|
|
|
|
* for the packet fall back on the network
|
|
|
|
* ambient value.
|
|
|
|
*/
|
|
|
|
strncpy(sip, smack_net_ambient, SMK_MAXLEN);
|
|
|
|
return;
|
|
|
|
}
|
|
|
|
/*
|
|
|
|
* Get the categories, if any
|
|
|
|
*/
|
|
|
|
memset(smack, '\0', SMK_LABELLEN);
|
|
|
|
if ((sap->flags & NETLBL_SECATTR_MLS_CAT) != 0)
|
|
|
|
for (pcat = -1;;) {
|
|
|
|
pcat = netlbl_secattr_catmap_walk(sap->attr.mls.cat,
|
|
|
|
pcat + 1);
|
|
|
|
if (pcat < 0)
|
|
|
|
break;
|
|
|
|
smack_catset_bit(pcat, smack);
|
|
|
|
}
|
|
|
|
/*
|
|
|
|
* If it is CIPSO using smack direct mapping
|
|
|
|
* we are already done. WeeHee.
|
|
|
|
*/
|
|
|
|
if (sap->attr.mls.lvl == smack_cipso_direct) {
|
|
|
|
memcpy(sip, smack, SMK_MAXLEN);
|
|
|
|
return;
|
|
|
|
}
|
|
|
|
/*
|
|
|
|
* Look it up in the supplied table if it is not a direct mapping.
|
|
|
|
*/
|
|
|
|
smack_from_cipso(sap->attr.mls.lvl, smack, sip);
|
|
|
|
return;
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_socket_sock_rcv_skb - Smack packet delivery access check
|
|
|
|
* @sk: socket
|
|
|
|
* @skb: packet
|
|
|
|
*
|
|
|
|
* Returns 0 if the packet should be delivered, an error code otherwise
|
|
|
|
*/
|
|
|
|
static int smack_socket_sock_rcv_skb(struct sock *sk, struct sk_buff *skb)
|
|
|
|
{
|
|
|
|
struct netlbl_lsm_secattr secattr;
|
|
|
|
struct socket_smack *ssp = sk->sk_security;
|
|
|
|
char smack[SMK_LABELLEN];
|
|
|
|
int rc;
|
|
|
|
|
|
|
|
if (sk->sk_family != PF_INET && sk->sk_family != PF_INET6)
|
|
|
|
return 0;
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Translate what netlabel gave us.
|
|
|
|
*/
|
|
|
|
memset(smack, '\0', SMK_LABELLEN);
|
|
|
|
netlbl_secattr_init(&secattr);
|
|
|
|
rc = netlbl_skbuff_getattr(skb, sk->sk_family, &secattr);
|
|
|
|
if (rc == 0)
|
|
|
|
smack_from_secattr(&secattr, smack);
|
|
|
|
else
|
|
|
|
strncpy(smack, smack_net_ambient, SMK_MAXLEN);
|
|
|
|
netlbl_secattr_destroy(&secattr);
|
|
|
|
/*
|
|
|
|
* Receiving a packet requires that the other end
|
|
|
|
* be able to write here. Read access is not required.
|
|
|
|
* This is the simplist possible security model
|
|
|
|
* for networking.
|
|
|
|
*/
|
|
|
|
return smk_access(smack, ssp->smk_in, MAY_WRITE);
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_socket_getpeersec_stream - pull in packet label
|
|
|
|
* @sock: the socket
|
|
|
|
* @optval: user's destination
|
|
|
|
* @optlen: size thereof
|
|
|
|
* @len: max thereoe
|
|
|
|
*
|
|
|
|
* returns zero on success, an error code otherwise
|
|
|
|
*/
|
|
|
|
static int smack_socket_getpeersec_stream(struct socket *sock,
|
|
|
|
char __user *optval,
|
|
|
|
int __user *optlen, unsigned len)
|
|
|
|
{
|
|
|
|
struct socket_smack *ssp;
|
|
|
|
int slen;
|
|
|
|
int rc = 0;
|
|
|
|
|
|
|
|
ssp = sock->sk->sk_security;
|
|
|
|
slen = strlen(ssp->smk_packet) + 1;
|
|
|
|
|
|
|
|
if (slen > len)
|
|
|
|
rc = -ERANGE;
|
|
|
|
else if (copy_to_user(optval, ssp->smk_packet, slen) != 0)
|
|
|
|
rc = -EFAULT;
|
|
|
|
|
|
|
|
if (put_user(slen, optlen) != 0)
|
|
|
|
rc = -EFAULT;
|
|
|
|
|
|
|
|
return rc;
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_socket_getpeersec_dgram - pull in packet label
|
|
|
|
* @sock: the socket
|
|
|
|
* @skb: packet data
|
|
|
|
* @secid: pointer to where to put the secid of the packet
|
|
|
|
*
|
|
|
|
* Sets the netlabel socket state on sk from parent
|
|
|
|
*/
|
|
|
|
static int smack_socket_getpeersec_dgram(struct socket *sock,
|
|
|
|
struct sk_buff *skb, u32 *secid)
|
|
|
|
|
|
|
|
{
|
|
|
|
struct netlbl_lsm_secattr secattr;
|
|
|
|
struct sock *sk;
|
|
|
|
char smack[SMK_LABELLEN];
|
|
|
|
int family = PF_INET;
|
|
|
|
u32 s;
|
|
|
|
int rc;
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Only works for families with packets.
|
|
|
|
*/
|
|
|
|
if (sock != NULL) {
|
|
|
|
sk = sock->sk;
|
|
|
|
if (sk->sk_family != PF_INET && sk->sk_family != PF_INET6)
|
|
|
|
return 0;
|
|
|
|
family = sk->sk_family;
|
|
|
|
}
|
|
|
|
/*
|
|
|
|
* Translate what netlabel gave us.
|
|
|
|
*/
|
|
|
|
memset(smack, '\0', SMK_LABELLEN);
|
|
|
|
netlbl_secattr_init(&secattr);
|
|
|
|
rc = netlbl_skbuff_getattr(skb, family, &secattr);
|
|
|
|
if (rc == 0)
|
|
|
|
smack_from_secattr(&secattr, smack);
|
|
|
|
netlbl_secattr_destroy(&secattr);
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Give up if we couldn't get anything
|
|
|
|
*/
|
|
|
|
if (rc != 0)
|
|
|
|
return rc;
|
|
|
|
|
|
|
|
s = smack_to_secid(smack);
|
|
|
|
if (s == 0)
|
|
|
|
return -EINVAL;
|
|
|
|
|
|
|
|
*secid = s;
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_sock_graft - graft access state between two sockets
|
|
|
|
* @sk: fresh sock
|
|
|
|
* @parent: donor socket
|
|
|
|
*
|
|
|
|
* Sets the netlabel socket state on sk from parent
|
|
|
|
*/
|
|
|
|
static void smack_sock_graft(struct sock *sk, struct socket *parent)
|
|
|
|
{
|
|
|
|
struct socket_smack *ssp;
|
|
|
|
int rc;
|
|
|
|
|
|
|
|
if (sk == NULL)
|
|
|
|
return;
|
|
|
|
|
|
|
|
if (sk->sk_family != PF_INET && sk->sk_family != PF_INET6)
|
|
|
|
return;
|
|
|
|
|
|
|
|
ssp = sk->sk_security;
|
|
|
|
ssp->smk_in = current->security;
|
|
|
|
ssp->smk_out = current->security;
|
|
|
|
ssp->smk_packet[0] = '\0';
|
|
|
|
|
|
|
|
rc = smack_netlabel(sk);
|
2008-02-15 23:24:25 +00:00
|
|
|
if (rc != 0)
|
|
|
|
printk(KERN_WARNING "Smack: \"%s\" netlbl error %d.\n",
|
|
|
|
__func__, -rc);
|
Smack: Simplified Mandatory Access Control Kernel
Smack is the Simplified Mandatory Access Control Kernel.
Smack implements mandatory access control (MAC) using labels
attached to tasks and data containers, including files, SVIPC,
and other tasks. Smack is a kernel based scheme that requires
an absolute minimum of application support and a very small
amount of configuration data.
Smack uses extended attributes and
provides a set of general mount options, borrowing technics used
elsewhere. Smack uses netlabel for CIPSO labeling. Smack provides
a pseudo-filesystem smackfs that is used for manipulation of
system Smack attributes.
The patch, patches for ls and sshd, a README, a startup script,
and x86 binaries for ls and sshd are also available on
http://www.schaufler-ca.com
Development has been done using Fedora Core 7 in a virtual machine
environment and on an old Sony laptop.
Smack provides mandatory access controls based on the label attached
to a task and the label attached to the object it is attempting to
access. Smack labels are deliberately short (1-23 characters) text
strings. Single character labels using special characters are reserved
for system use. The only operation applied to Smack labels is equality
comparison. No wildcards or expressions, regular or otherwise, are
used. Smack labels are composed of printable characters and may not
include "/".
A file always gets the Smack label of the task that created it.
Smack defines and uses these labels:
"*" - pronounced "star"
"_" - pronounced "floor"
"^" - pronounced "hat"
"?" - pronounced "huh"
The access rules enforced by Smack are, in order:
1. Any access requested by a task labeled "*" is denied.
2. A read or execute access requested by a task labeled "^"
is permitted.
3. A read or execute access requested on an object labeled "_"
is permitted.
4. Any access requested on an object labeled "*" is permitted.
5. Any access requested by a task on an object with the same
label is permitted.
6. Any access requested that is explicitly defined in the loaded
rule set is permitted.
7. Any other access is denied.
Rules may be explicitly defined by writing subject,object,access
triples to /smack/load.
Smack rule sets can be easily defined that describe Bell&LaPadula
sensitivity, Biba integrity, and a variety of interesting
configurations. Smack rule sets can be modified on the fly to
accommodate changes in the operating environment or even the time
of day.
Some practical use cases:
Hierarchical levels. The less common of the two usual uses
for MLS systems is to define hierarchical levels, often
unclassified, confidential, secret, and so on. To set up smack
to support this, these rules could be defined:
C Unclass rx
S C rx
S Unclass rx
TS S rx
TS C rx
TS Unclass rx
A TS process can read S, C, and Unclass data, but cannot write it.
An S process can read C and Unclass. Note that specifying that
TS can read S and S can read C does not imply TS can read C, it
has to be explicitly stated.
Non-hierarchical categories. This is the more common of the
usual uses for an MLS system. Since the default rule is that a
subject cannot access an object with a different label no
access rules are required to implement compartmentalization.
A case that the Bell & LaPadula policy does not allow is demonstrated
with this Smack access rule:
A case that Bell&LaPadula does not allow that Smack does:
ESPN ABC r
ABC ESPN r
On my portable video device I have two applications, one that
shows ABC programming and the other ESPN programming. ESPN wants
to show me sport stories that show up as news, and ABC will
only provide minimal information about a sports story if ESPN
is covering it. Each side can look at the other's info, neither
can change the other. Neither can see what FOX is up to, which
is just as well all things considered.
Another case that I especially like:
SatData Guard w
Guard Publish w
A program running with the Guard label opens a UDP socket and
accepts messages sent by a program running with a SatData label.
The Guard program inspects the message to ensure it is wholesome
and if it is sends it to a program running with the Publish label.
This program then puts the information passed in an appropriate
place. Note that the Guard program cannot write to a Publish
file system object because file system semanitic require read as
well as write.
The four cases (categories, levels, mutual read, guardbox) here
are all quite real, and problems I've been asked to solve over
the years. The first two are easy to do with traditonal MLS systems
while the last two you can't without invoking privilege, at least
for a while.
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Cc: Joshua Brindle <method@manicmethod.com>
Cc: Paul Moore <paul.moore@hp.com>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: Chris Wright <chrisw@sous-sol.org>
Cc: James Morris <jmorris@namei.org>
Cc: "Ahmed S. Darwish" <darwish.07@gmail.com>
Cc: Andrew G. Morgan <morgan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-05 06:29:50 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_inet_conn_request - Smack access check on connect
|
|
|
|
* @sk: socket involved
|
|
|
|
* @skb: packet
|
|
|
|
* @req: unused
|
|
|
|
*
|
|
|
|
* Returns 0 if a task with the packet label could write to
|
|
|
|
* the socket, otherwise an error code
|
|
|
|
*/
|
|
|
|
static int smack_inet_conn_request(struct sock *sk, struct sk_buff *skb,
|
|
|
|
struct request_sock *req)
|
|
|
|
{
|
|
|
|
struct netlbl_lsm_secattr skb_secattr;
|
|
|
|
struct socket_smack *ssp = sk->sk_security;
|
|
|
|
char smack[SMK_LABELLEN];
|
|
|
|
int rc;
|
|
|
|
|
|
|
|
if (skb == NULL)
|
|
|
|
return -EACCES;
|
|
|
|
|
|
|
|
memset(smack, '\0', SMK_LABELLEN);
|
|
|
|
netlbl_secattr_init(&skb_secattr);
|
|
|
|
rc = netlbl_skbuff_getattr(skb, sk->sk_family, &skb_secattr);
|
|
|
|
if (rc == 0)
|
|
|
|
smack_from_secattr(&skb_secattr, smack);
|
|
|
|
else
|
|
|
|
strncpy(smack, smack_known_huh.smk_known, SMK_MAXLEN);
|
|
|
|
netlbl_secattr_destroy(&skb_secattr);
|
|
|
|
/*
|
|
|
|
* Receiving a packet requires that the other end
|
|
|
|
* be able to write here. Read access is not required.
|
|
|
|
*
|
|
|
|
* If the request is successful save the peer's label
|
|
|
|
* so that SO_PEERCRED can report it.
|
|
|
|
*/
|
|
|
|
rc = smk_access(smack, ssp->smk_in, MAY_WRITE);
|
|
|
|
if (rc == 0)
|
|
|
|
strncpy(ssp->smk_packet, smack, SMK_MAXLEN);
|
|
|
|
|
|
|
|
return rc;
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Key management security hooks
|
|
|
|
*
|
|
|
|
* Casey has not tested key support very heavily.
|
|
|
|
* The permission check is most likely too restrictive.
|
|
|
|
* If you care about keys please have a look.
|
|
|
|
*/
|
|
|
|
#ifdef CONFIG_KEYS
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_key_alloc - Set the key security blob
|
|
|
|
* @key: object
|
|
|
|
* @tsk: the task associated with the key
|
|
|
|
* @flags: unused
|
|
|
|
*
|
|
|
|
* No allocation required
|
|
|
|
*
|
|
|
|
* Returns 0
|
|
|
|
*/
|
|
|
|
static int smack_key_alloc(struct key *key, struct task_struct *tsk,
|
|
|
|
unsigned long flags)
|
|
|
|
{
|
|
|
|
key->security = tsk->security;
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_key_free - Clear the key security blob
|
|
|
|
* @key: the object
|
|
|
|
*
|
|
|
|
* Clear the blob pointer
|
|
|
|
*/
|
|
|
|
static void smack_key_free(struct key *key)
|
|
|
|
{
|
|
|
|
key->security = NULL;
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* smack_key_permission - Smack access on a key
|
|
|
|
* @key_ref: gets to the object
|
|
|
|
* @context: task involved
|
|
|
|
* @perm: unused
|
|
|
|
*
|
|
|
|
* Return 0 if the task has read and write to the object,
|
|
|
|
* an error code otherwise
|
|
|
|
*/
|
|
|
|
static int smack_key_permission(key_ref_t key_ref,
|
|
|
|
struct task_struct *context, key_perm_t perm)
|
|
|
|
{
|
|
|
|
struct key *keyp;
|
|
|
|
|
|
|
|
keyp = key_ref_to_ptr(key_ref);
|
|
|
|
if (keyp == NULL)
|
|
|
|
return -EINVAL;
|
|
|
|
/*
|
|
|
|
* If the key hasn't been initialized give it access so that
|
|
|
|
* it may do so.
|
|
|
|
*/
|
|
|
|
if (keyp->security == NULL)
|
|
|
|
return 0;
|
|
|
|
/*
|
|
|
|
* This should not occur
|
|
|
|
*/
|
|
|
|
if (context->security == NULL)
|
|
|
|
return -EACCES;
|
|
|
|
|
|
|
|
return smk_access(context->security, keyp->security, MAY_READWRITE);
|
|
|
|
}
|
|
|
|
#endif /* CONFIG_KEYS */
|
|
|
|
|
|
|
|
/*
|
|
|
|
* smack_secid_to_secctx - return the smack label for a secid
|
|
|
|
* @secid: incoming integer
|
|
|
|
* @secdata: destination
|
|
|
|
* @seclen: how long it is
|
|
|
|
*
|
|
|
|
* Exists for networking code.
|
|
|
|
*/
|
|
|
|
static int smack_secid_to_secctx(u32 secid, char **secdata, u32 *seclen)
|
|
|
|
{
|
|
|
|
char *sp = smack_from_secid(secid);
|
|
|
|
|
|
|
|
*secdata = sp;
|
|
|
|
*seclen = strlen(sp);
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
2008-02-15 23:24:25 +00:00
|
|
|
/*
|
|
|
|
* smack_secctx_to_secid - return the secid for a smack label
|
|
|
|
* @secdata: smack label
|
|
|
|
* @seclen: how long result is
|
|
|
|
* @secid: outgoing integer
|
|
|
|
*
|
|
|
|
* Exists for audit and networking code.
|
|
|
|
*/
|
|
|
|
static int smack_secctx_to_secid(char *secdata, u32 seclen, u32 *secid)
|
|
|
|
{
|
|
|
|
*secid = smack_to_secid(secdata);
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
Smack: Simplified Mandatory Access Control Kernel
Smack is the Simplified Mandatory Access Control Kernel.
Smack implements mandatory access control (MAC) using labels
attached to tasks and data containers, including files, SVIPC,
and other tasks. Smack is a kernel based scheme that requires
an absolute minimum of application support and a very small
amount of configuration data.
Smack uses extended attributes and
provides a set of general mount options, borrowing technics used
elsewhere. Smack uses netlabel for CIPSO labeling. Smack provides
a pseudo-filesystem smackfs that is used for manipulation of
system Smack attributes.
The patch, patches for ls and sshd, a README, a startup script,
and x86 binaries for ls and sshd are also available on
http://www.schaufler-ca.com
Development has been done using Fedora Core 7 in a virtual machine
environment and on an old Sony laptop.
Smack provides mandatory access controls based on the label attached
to a task and the label attached to the object it is attempting to
access. Smack labels are deliberately short (1-23 characters) text
strings. Single character labels using special characters are reserved
for system use. The only operation applied to Smack labels is equality
comparison. No wildcards or expressions, regular or otherwise, are
used. Smack labels are composed of printable characters and may not
include "/".
A file always gets the Smack label of the task that created it.
Smack defines and uses these labels:
"*" - pronounced "star"
"_" - pronounced "floor"
"^" - pronounced "hat"
"?" - pronounced "huh"
The access rules enforced by Smack are, in order:
1. Any access requested by a task labeled "*" is denied.
2. A read or execute access requested by a task labeled "^"
is permitted.
3. A read or execute access requested on an object labeled "_"
is permitted.
4. Any access requested on an object labeled "*" is permitted.
5. Any access requested by a task on an object with the same
label is permitted.
6. Any access requested that is explicitly defined in the loaded
rule set is permitted.
7. Any other access is denied.
Rules may be explicitly defined by writing subject,object,access
triples to /smack/load.
Smack rule sets can be easily defined that describe Bell&LaPadula
sensitivity, Biba integrity, and a variety of interesting
configurations. Smack rule sets can be modified on the fly to
accommodate changes in the operating environment or even the time
of day.
Some practical use cases:
Hierarchical levels. The less common of the two usual uses
for MLS systems is to define hierarchical levels, often
unclassified, confidential, secret, and so on. To set up smack
to support this, these rules could be defined:
C Unclass rx
S C rx
S Unclass rx
TS S rx
TS C rx
TS Unclass rx
A TS process can read S, C, and Unclass data, but cannot write it.
An S process can read C and Unclass. Note that specifying that
TS can read S and S can read C does not imply TS can read C, it
has to be explicitly stated.
Non-hierarchical categories. This is the more common of the
usual uses for an MLS system. Since the default rule is that a
subject cannot access an object with a different label no
access rules are required to implement compartmentalization.
A case that the Bell & LaPadula policy does not allow is demonstrated
with this Smack access rule:
A case that Bell&LaPadula does not allow that Smack does:
ESPN ABC r
ABC ESPN r
On my portable video device I have two applications, one that
shows ABC programming and the other ESPN programming. ESPN wants
to show me sport stories that show up as news, and ABC will
only provide minimal information about a sports story if ESPN
is covering it. Each side can look at the other's info, neither
can change the other. Neither can see what FOX is up to, which
is just as well all things considered.
Another case that I especially like:
SatData Guard w
Guard Publish w
A program running with the Guard label opens a UDP socket and
accepts messages sent by a program running with a SatData label.
The Guard program inspects the message to ensure it is wholesome
and if it is sends it to a program running with the Publish label.
This program then puts the information passed in an appropriate
place. Note that the Guard program cannot write to a Publish
file system object because file system semanitic require read as
well as write.
The four cases (categories, levels, mutual read, guardbox) here
are all quite real, and problems I've been asked to solve over
the years. The first two are easy to do with traditonal MLS systems
while the last two you can't without invoking privilege, at least
for a while.
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Cc: Joshua Brindle <method@manicmethod.com>
Cc: Paul Moore <paul.moore@hp.com>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: Chris Wright <chrisw@sous-sol.org>
Cc: James Morris <jmorris@namei.org>
Cc: "Ahmed S. Darwish" <darwish.07@gmail.com>
Cc: Andrew G. Morgan <morgan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-05 06:29:50 +00:00
|
|
|
/*
|
|
|
|
* smack_release_secctx - don't do anything.
|
|
|
|
* @key_ref: unused
|
|
|
|
* @context: unused
|
|
|
|
* @perm: unused
|
|
|
|
*
|
|
|
|
* Exists to make sure nothing gets done, and properly
|
|
|
|
*/
|
|
|
|
static void smack_release_secctx(char *secdata, u32 seclen)
|
|
|
|
{
|
|
|
|
}
|
|
|
|
|
|
|
|
static struct security_operations smack_ops = {
|
|
|
|
.ptrace = smack_ptrace,
|
|
|
|
.capget = cap_capget,
|
|
|
|
.capset_check = cap_capset_check,
|
|
|
|
.capset_set = cap_capset_set,
|
|
|
|
.capable = cap_capable,
|
|
|
|
.syslog = smack_syslog,
|
|
|
|
.settime = cap_settime,
|
|
|
|
.vm_enough_memory = cap_vm_enough_memory,
|
|
|
|
|
|
|
|
.bprm_apply_creds = cap_bprm_apply_creds,
|
|
|
|
.bprm_set_security = cap_bprm_set_security,
|
|
|
|
.bprm_secureexec = cap_bprm_secureexec,
|
|
|
|
|
|
|
|
.sb_alloc_security = smack_sb_alloc_security,
|
|
|
|
.sb_free_security = smack_sb_free_security,
|
|
|
|
.sb_copy_data = smack_sb_copy_data,
|
|
|
|
.sb_kern_mount = smack_sb_kern_mount,
|
|
|
|
.sb_statfs = smack_sb_statfs,
|
|
|
|
.sb_mount = smack_sb_mount,
|
|
|
|
.sb_umount = smack_sb_umount,
|
|
|
|
|
|
|
|
.inode_alloc_security = smack_inode_alloc_security,
|
|
|
|
.inode_free_security = smack_inode_free_security,
|
|
|
|
.inode_init_security = smack_inode_init_security,
|
|
|
|
.inode_link = smack_inode_link,
|
|
|
|
.inode_unlink = smack_inode_unlink,
|
|
|
|
.inode_rmdir = smack_inode_rmdir,
|
|
|
|
.inode_rename = smack_inode_rename,
|
|
|
|
.inode_permission = smack_inode_permission,
|
|
|
|
.inode_setattr = smack_inode_setattr,
|
|
|
|
.inode_getattr = smack_inode_getattr,
|
|
|
|
.inode_setxattr = smack_inode_setxattr,
|
|
|
|
.inode_post_setxattr = smack_inode_post_setxattr,
|
|
|
|
.inode_getxattr = smack_inode_getxattr,
|
|
|
|
.inode_removexattr = smack_inode_removexattr,
|
2008-02-23 23:24:04 +00:00
|
|
|
.inode_need_killpriv = cap_inode_need_killpriv,
|
|
|
|
.inode_killpriv = cap_inode_killpriv,
|
Smack: Simplified Mandatory Access Control Kernel
Smack is the Simplified Mandatory Access Control Kernel.
Smack implements mandatory access control (MAC) using labels
attached to tasks and data containers, including files, SVIPC,
and other tasks. Smack is a kernel based scheme that requires
an absolute minimum of application support and a very small
amount of configuration data.
Smack uses extended attributes and
provides a set of general mount options, borrowing technics used
elsewhere. Smack uses netlabel for CIPSO labeling. Smack provides
a pseudo-filesystem smackfs that is used for manipulation of
system Smack attributes.
The patch, patches for ls and sshd, a README, a startup script,
and x86 binaries for ls and sshd are also available on
http://www.schaufler-ca.com
Development has been done using Fedora Core 7 in a virtual machine
environment and on an old Sony laptop.
Smack provides mandatory access controls based on the label attached
to a task and the label attached to the object it is attempting to
access. Smack labels are deliberately short (1-23 characters) text
strings. Single character labels using special characters are reserved
for system use. The only operation applied to Smack labels is equality
comparison. No wildcards or expressions, regular or otherwise, are
used. Smack labels are composed of printable characters and may not
include "/".
A file always gets the Smack label of the task that created it.
Smack defines and uses these labels:
"*" - pronounced "star"
"_" - pronounced "floor"
"^" - pronounced "hat"
"?" - pronounced "huh"
The access rules enforced by Smack are, in order:
1. Any access requested by a task labeled "*" is denied.
2. A read or execute access requested by a task labeled "^"
is permitted.
3. A read or execute access requested on an object labeled "_"
is permitted.
4. Any access requested on an object labeled "*" is permitted.
5. Any access requested by a task on an object with the same
label is permitted.
6. Any access requested that is explicitly defined in the loaded
rule set is permitted.
7. Any other access is denied.
Rules may be explicitly defined by writing subject,object,access
triples to /smack/load.
Smack rule sets can be easily defined that describe Bell&LaPadula
sensitivity, Biba integrity, and a variety of interesting
configurations. Smack rule sets can be modified on the fly to
accommodate changes in the operating environment or even the time
of day.
Some practical use cases:
Hierarchical levels. The less common of the two usual uses
for MLS systems is to define hierarchical levels, often
unclassified, confidential, secret, and so on. To set up smack
to support this, these rules could be defined:
C Unclass rx
S C rx
S Unclass rx
TS S rx
TS C rx
TS Unclass rx
A TS process can read S, C, and Unclass data, but cannot write it.
An S process can read C and Unclass. Note that specifying that
TS can read S and S can read C does not imply TS can read C, it
has to be explicitly stated.
Non-hierarchical categories. This is the more common of the
usual uses for an MLS system. Since the default rule is that a
subject cannot access an object with a different label no
access rules are required to implement compartmentalization.
A case that the Bell & LaPadula policy does not allow is demonstrated
with this Smack access rule:
A case that Bell&LaPadula does not allow that Smack does:
ESPN ABC r
ABC ESPN r
On my portable video device I have two applications, one that
shows ABC programming and the other ESPN programming. ESPN wants
to show me sport stories that show up as news, and ABC will
only provide minimal information about a sports story if ESPN
is covering it. Each side can look at the other's info, neither
can change the other. Neither can see what FOX is up to, which
is just as well all things considered.
Another case that I especially like:
SatData Guard w
Guard Publish w
A program running with the Guard label opens a UDP socket and
accepts messages sent by a program running with a SatData label.
The Guard program inspects the message to ensure it is wholesome
and if it is sends it to a program running with the Publish label.
This program then puts the information passed in an appropriate
place. Note that the Guard program cannot write to a Publish
file system object because file system semanitic require read as
well as write.
The four cases (categories, levels, mutual read, guardbox) here
are all quite real, and problems I've been asked to solve over
the years. The first two are easy to do with traditonal MLS systems
while the last two you can't without invoking privilege, at least
for a while.
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Cc: Joshua Brindle <method@manicmethod.com>
Cc: Paul Moore <paul.moore@hp.com>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: Chris Wright <chrisw@sous-sol.org>
Cc: James Morris <jmorris@namei.org>
Cc: "Ahmed S. Darwish" <darwish.07@gmail.com>
Cc: Andrew G. Morgan <morgan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-05 06:29:50 +00:00
|
|
|
.inode_getsecurity = smack_inode_getsecurity,
|
|
|
|
.inode_setsecurity = smack_inode_setsecurity,
|
|
|
|
.inode_listsecurity = smack_inode_listsecurity,
|
|
|
|
|
|
|
|
.file_permission = smack_file_permission,
|
|
|
|
.file_alloc_security = smack_file_alloc_security,
|
|
|
|
.file_free_security = smack_file_free_security,
|
|
|
|
.file_ioctl = smack_file_ioctl,
|
|
|
|
.file_lock = smack_file_lock,
|
|
|
|
.file_fcntl = smack_file_fcntl,
|
|
|
|
.file_set_fowner = smack_file_set_fowner,
|
|
|
|
.file_send_sigiotask = smack_file_send_sigiotask,
|
|
|
|
.file_receive = smack_file_receive,
|
|
|
|
|
|
|
|
.task_alloc_security = smack_task_alloc_security,
|
|
|
|
.task_free_security = smack_task_free_security,
|
|
|
|
.task_post_setuid = cap_task_post_setuid,
|
|
|
|
.task_setpgid = smack_task_setpgid,
|
|
|
|
.task_getpgid = smack_task_getpgid,
|
|
|
|
.task_getsid = smack_task_getsid,
|
|
|
|
.task_getsecid = smack_task_getsecid,
|
|
|
|
.task_setnice = smack_task_setnice,
|
|
|
|
.task_setioprio = smack_task_setioprio,
|
|
|
|
.task_getioprio = smack_task_getioprio,
|
|
|
|
.task_setscheduler = smack_task_setscheduler,
|
|
|
|
.task_getscheduler = smack_task_getscheduler,
|
|
|
|
.task_movememory = smack_task_movememory,
|
|
|
|
.task_kill = smack_task_kill,
|
|
|
|
.task_wait = smack_task_wait,
|
|
|
|
.task_reparent_to_init = cap_task_reparent_to_init,
|
|
|
|
.task_to_inode = smack_task_to_inode,
|
|
|
|
|
|
|
|
.ipc_permission = smack_ipc_permission,
|
|
|
|
|
|
|
|
.msg_msg_alloc_security = smack_msg_msg_alloc_security,
|
|
|
|
.msg_msg_free_security = smack_msg_msg_free_security,
|
|
|
|
|
|
|
|
.msg_queue_alloc_security = smack_msg_queue_alloc_security,
|
|
|
|
.msg_queue_free_security = smack_msg_queue_free_security,
|
|
|
|
.msg_queue_associate = smack_msg_queue_associate,
|
|
|
|
.msg_queue_msgctl = smack_msg_queue_msgctl,
|
|
|
|
.msg_queue_msgsnd = smack_msg_queue_msgsnd,
|
|
|
|
.msg_queue_msgrcv = smack_msg_queue_msgrcv,
|
|
|
|
|
|
|
|
.shm_alloc_security = smack_shm_alloc_security,
|
|
|
|
.shm_free_security = smack_shm_free_security,
|
|
|
|
.shm_associate = smack_shm_associate,
|
|
|
|
.shm_shmctl = smack_shm_shmctl,
|
|
|
|
.shm_shmat = smack_shm_shmat,
|
|
|
|
|
|
|
|
.sem_alloc_security = smack_sem_alloc_security,
|
|
|
|
.sem_free_security = smack_sem_free_security,
|
|
|
|
.sem_associate = smack_sem_associate,
|
|
|
|
.sem_semctl = smack_sem_semctl,
|
|
|
|
.sem_semop = smack_sem_semop,
|
|
|
|
|
|
|
|
.netlink_send = cap_netlink_send,
|
|
|
|
.netlink_recv = cap_netlink_recv,
|
|
|
|
|
2008-02-23 23:24:04 +00:00
|
|
|
.register_security = smack_register_security,
|
|
|
|
|
Smack: Simplified Mandatory Access Control Kernel
Smack is the Simplified Mandatory Access Control Kernel.
Smack implements mandatory access control (MAC) using labels
attached to tasks and data containers, including files, SVIPC,
and other tasks. Smack is a kernel based scheme that requires
an absolute minimum of application support and a very small
amount of configuration data.
Smack uses extended attributes and
provides a set of general mount options, borrowing technics used
elsewhere. Smack uses netlabel for CIPSO labeling. Smack provides
a pseudo-filesystem smackfs that is used for manipulation of
system Smack attributes.
The patch, patches for ls and sshd, a README, a startup script,
and x86 binaries for ls and sshd are also available on
http://www.schaufler-ca.com
Development has been done using Fedora Core 7 in a virtual machine
environment and on an old Sony laptop.
Smack provides mandatory access controls based on the label attached
to a task and the label attached to the object it is attempting to
access. Smack labels are deliberately short (1-23 characters) text
strings. Single character labels using special characters are reserved
for system use. The only operation applied to Smack labels is equality
comparison. No wildcards or expressions, regular or otherwise, are
used. Smack labels are composed of printable characters and may not
include "/".
A file always gets the Smack label of the task that created it.
Smack defines and uses these labels:
"*" - pronounced "star"
"_" - pronounced "floor"
"^" - pronounced "hat"
"?" - pronounced "huh"
The access rules enforced by Smack are, in order:
1. Any access requested by a task labeled "*" is denied.
2. A read or execute access requested by a task labeled "^"
is permitted.
3. A read or execute access requested on an object labeled "_"
is permitted.
4. Any access requested on an object labeled "*" is permitted.
5. Any access requested by a task on an object with the same
label is permitted.
6. Any access requested that is explicitly defined in the loaded
rule set is permitted.
7. Any other access is denied.
Rules may be explicitly defined by writing subject,object,access
triples to /smack/load.
Smack rule sets can be easily defined that describe Bell&LaPadula
sensitivity, Biba integrity, and a variety of interesting
configurations. Smack rule sets can be modified on the fly to
accommodate changes in the operating environment or even the time
of day.
Some practical use cases:
Hierarchical levels. The less common of the two usual uses
for MLS systems is to define hierarchical levels, often
unclassified, confidential, secret, and so on. To set up smack
to support this, these rules could be defined:
C Unclass rx
S C rx
S Unclass rx
TS S rx
TS C rx
TS Unclass rx
A TS process can read S, C, and Unclass data, but cannot write it.
An S process can read C and Unclass. Note that specifying that
TS can read S and S can read C does not imply TS can read C, it
has to be explicitly stated.
Non-hierarchical categories. This is the more common of the
usual uses for an MLS system. Since the default rule is that a
subject cannot access an object with a different label no
access rules are required to implement compartmentalization.
A case that the Bell & LaPadula policy does not allow is demonstrated
with this Smack access rule:
A case that Bell&LaPadula does not allow that Smack does:
ESPN ABC r
ABC ESPN r
On my portable video device I have two applications, one that
shows ABC programming and the other ESPN programming. ESPN wants
to show me sport stories that show up as news, and ABC will
only provide minimal information about a sports story if ESPN
is covering it. Each side can look at the other's info, neither
can change the other. Neither can see what FOX is up to, which
is just as well all things considered.
Another case that I especially like:
SatData Guard w
Guard Publish w
A program running with the Guard label opens a UDP socket and
accepts messages sent by a program running with a SatData label.
The Guard program inspects the message to ensure it is wholesome
and if it is sends it to a program running with the Publish label.
This program then puts the information passed in an appropriate
place. Note that the Guard program cannot write to a Publish
file system object because file system semanitic require read as
well as write.
The four cases (categories, levels, mutual read, guardbox) here
are all quite real, and problems I've been asked to solve over
the years. The first two are easy to do with traditonal MLS systems
while the last two you can't without invoking privilege, at least
for a while.
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Cc: Joshua Brindle <method@manicmethod.com>
Cc: Paul Moore <paul.moore@hp.com>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: Chris Wright <chrisw@sous-sol.org>
Cc: James Morris <jmorris@namei.org>
Cc: "Ahmed S. Darwish" <darwish.07@gmail.com>
Cc: Andrew G. Morgan <morgan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-05 06:29:50 +00:00
|
|
|
.d_instantiate = smack_d_instantiate,
|
|
|
|
|
|
|
|
.getprocattr = smack_getprocattr,
|
|
|
|
.setprocattr = smack_setprocattr,
|
|
|
|
|
|
|
|
.unix_stream_connect = smack_unix_stream_connect,
|
|
|
|
.unix_may_send = smack_unix_may_send,
|
|
|
|
|
|
|
|
.socket_post_create = smack_socket_post_create,
|
|
|
|
.socket_sock_rcv_skb = smack_socket_sock_rcv_skb,
|
|
|
|
.socket_getpeersec_stream = smack_socket_getpeersec_stream,
|
|
|
|
.socket_getpeersec_dgram = smack_socket_getpeersec_dgram,
|
|
|
|
.sk_alloc_security = smack_sk_alloc_security,
|
|
|
|
.sk_free_security = smack_sk_free_security,
|
|
|
|
.sock_graft = smack_sock_graft,
|
|
|
|
.inet_conn_request = smack_inet_conn_request,
|
|
|
|
/* key management security hooks */
|
|
|
|
#ifdef CONFIG_KEYS
|
|
|
|
.key_alloc = smack_key_alloc,
|
|
|
|
.key_free = smack_key_free,
|
|
|
|
.key_permission = smack_key_permission,
|
|
|
|
#endif /* CONFIG_KEYS */
|
|
|
|
.secid_to_secctx = smack_secid_to_secctx,
|
2008-02-15 23:24:25 +00:00
|
|
|
.secctx_to_secid = smack_secctx_to_secid,
|
Smack: Simplified Mandatory Access Control Kernel
Smack is the Simplified Mandatory Access Control Kernel.
Smack implements mandatory access control (MAC) using labels
attached to tasks and data containers, including files, SVIPC,
and other tasks. Smack is a kernel based scheme that requires
an absolute minimum of application support and a very small
amount of configuration data.
Smack uses extended attributes and
provides a set of general mount options, borrowing technics used
elsewhere. Smack uses netlabel for CIPSO labeling. Smack provides
a pseudo-filesystem smackfs that is used for manipulation of
system Smack attributes.
The patch, patches for ls and sshd, a README, a startup script,
and x86 binaries for ls and sshd are also available on
http://www.schaufler-ca.com
Development has been done using Fedora Core 7 in a virtual machine
environment and on an old Sony laptop.
Smack provides mandatory access controls based on the label attached
to a task and the label attached to the object it is attempting to
access. Smack labels are deliberately short (1-23 characters) text
strings. Single character labels using special characters are reserved
for system use. The only operation applied to Smack labels is equality
comparison. No wildcards or expressions, regular or otherwise, are
used. Smack labels are composed of printable characters and may not
include "/".
A file always gets the Smack label of the task that created it.
Smack defines and uses these labels:
"*" - pronounced "star"
"_" - pronounced "floor"
"^" - pronounced "hat"
"?" - pronounced "huh"
The access rules enforced by Smack are, in order:
1. Any access requested by a task labeled "*" is denied.
2. A read or execute access requested by a task labeled "^"
is permitted.
3. A read or execute access requested on an object labeled "_"
is permitted.
4. Any access requested on an object labeled "*" is permitted.
5. Any access requested by a task on an object with the same
label is permitted.
6. Any access requested that is explicitly defined in the loaded
rule set is permitted.
7. Any other access is denied.
Rules may be explicitly defined by writing subject,object,access
triples to /smack/load.
Smack rule sets can be easily defined that describe Bell&LaPadula
sensitivity, Biba integrity, and a variety of interesting
configurations. Smack rule sets can be modified on the fly to
accommodate changes in the operating environment or even the time
of day.
Some practical use cases:
Hierarchical levels. The less common of the two usual uses
for MLS systems is to define hierarchical levels, often
unclassified, confidential, secret, and so on. To set up smack
to support this, these rules could be defined:
C Unclass rx
S C rx
S Unclass rx
TS S rx
TS C rx
TS Unclass rx
A TS process can read S, C, and Unclass data, but cannot write it.
An S process can read C and Unclass. Note that specifying that
TS can read S and S can read C does not imply TS can read C, it
has to be explicitly stated.
Non-hierarchical categories. This is the more common of the
usual uses for an MLS system. Since the default rule is that a
subject cannot access an object with a different label no
access rules are required to implement compartmentalization.
A case that the Bell & LaPadula policy does not allow is demonstrated
with this Smack access rule:
A case that Bell&LaPadula does not allow that Smack does:
ESPN ABC r
ABC ESPN r
On my portable video device I have two applications, one that
shows ABC programming and the other ESPN programming. ESPN wants
to show me sport stories that show up as news, and ABC will
only provide minimal information about a sports story if ESPN
is covering it. Each side can look at the other's info, neither
can change the other. Neither can see what FOX is up to, which
is just as well all things considered.
Another case that I especially like:
SatData Guard w
Guard Publish w
A program running with the Guard label opens a UDP socket and
accepts messages sent by a program running with a SatData label.
The Guard program inspects the message to ensure it is wholesome
and if it is sends it to a program running with the Publish label.
This program then puts the information passed in an appropriate
place. Note that the Guard program cannot write to a Publish
file system object because file system semanitic require read as
well as write.
The four cases (categories, levels, mutual read, guardbox) here
are all quite real, and problems I've been asked to solve over
the years. The first two are easy to do with traditonal MLS systems
while the last two you can't without invoking privilege, at least
for a while.
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Cc: Joshua Brindle <method@manicmethod.com>
Cc: Paul Moore <paul.moore@hp.com>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: Chris Wright <chrisw@sous-sol.org>
Cc: James Morris <jmorris@namei.org>
Cc: "Ahmed S. Darwish" <darwish.07@gmail.com>
Cc: Andrew G. Morgan <morgan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-05 06:29:50 +00:00
|
|
|
.release_secctx = smack_release_secctx,
|
|
|
|
};
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smack_init - initialize the smack system
|
|
|
|
*
|
|
|
|
* Returns 0
|
|
|
|
*/
|
|
|
|
static __init int smack_init(void)
|
|
|
|
{
|
|
|
|
printk(KERN_INFO "Smack: Initializing.\n");
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Set the security state for the initial task.
|
|
|
|
*/
|
|
|
|
current->security = &smack_known_floor.smk_known;
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Initialize locks
|
|
|
|
*/
|
|
|
|
spin_lock_init(&smack_known_unset.smk_cipsolock);
|
|
|
|
spin_lock_init(&smack_known_huh.smk_cipsolock);
|
|
|
|
spin_lock_init(&smack_known_hat.smk_cipsolock);
|
|
|
|
spin_lock_init(&smack_known_star.smk_cipsolock);
|
|
|
|
spin_lock_init(&smack_known_floor.smk_cipsolock);
|
|
|
|
spin_lock_init(&smack_known_invalid.smk_cipsolock);
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Register with LSM
|
|
|
|
*/
|
|
|
|
if (register_security(&smack_ops))
|
|
|
|
panic("smack: Unable to register with kernel.\n");
|
|
|
|
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Smack requires early initialization in order to label
|
|
|
|
* all processes and objects when they are created.
|
|
|
|
*/
|
|
|
|
security_initcall(smack_init);
|
|
|
|
|