linux/security/keys/keyctl.c
David Howells b5f545c880 [PATCH] keys: Permit running process to instantiate keys
Make it possible for a running process (such as gssapid) to be able to
instantiate a key, as was requested by Trond Myklebust for NFS4.

The patch makes the following changes:

 (1) A new, optional key type method has been added. This permits a key type
     to intercept requests at the point /sbin/request-key is about to be
     spawned and do something else with them - passing them over the
     rpc_pipefs files or netlink sockets for instance.

     The uninstantiated key, the authorisation key and the intended operation
     name are passed to the method.

 (2) The callout_info is no longer passed as an argument to /sbin/request-key
     to prevent unauthorised viewing of this data using ps or by looking in
     /proc/pid/cmdline.

     This means that the old /sbin/request-key program will not work with the
     patched kernel as it will expect to see an extra argument that is no
     longer there.

     A revised keyutils package will be made available tomorrow.

 (3) The callout_info is now attached to the authorisation key. Reading this
     key will retrieve the information.

 (4) A new field has been added to the task_struct. This holds the
     authorisation key currently active for a thread. Searches now look here
     for the caller's set of keys rather than looking for an auth key in the
     lowest level of the session keyring.

     This permits a thread to be servicing multiple requests at once and to
     switch between them. Note that this is per-thread, not per-process, and
     so is usable in multithreaded programs.

     The setting of this field is inherited across fork and exec.

 (5) A new keyctl function (KEYCTL_ASSUME_AUTHORITY) has been added that
     permits a thread to assume the authority to deal with an uninstantiated
     key. Assumption is only permitted if the authorisation key associated
     with the uninstantiated key is somewhere in the thread's keyrings.

     This function can also clear the assumption.

 (6) A new magic key specifier has been added to refer to the currently
     assumed authorisation key (KEY_SPEC_REQKEY_AUTH_KEY).

 (7) Instantiation will only proceed if the appropriate authorisation key is
     assumed first. The assumed authorisation key is discarded if
     instantiation is successful.

 (8) key_validate() is moved from the file of request_key functions to the
     file of permissions functions.

 (9) The documentation is updated.

From: <Valdis.Kletnieks@vt.edu>

    Build fix.

Signed-off-by: David Howells <dhowells@redhat.com>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Cc: Alexander Zangerl <az@bond.edu.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-08 20:13:53 -08:00

1150 lines
26 KiB
C

/* keyctl.c: userspace keyctl operations
*
* Copyright (C) 2004-5 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/syscalls.h>
#include <linux/keyctl.h>
#include <linux/fs.h>
#include <linux/err.h>
#include <asm/uaccess.h>
#include "internal.h"
/*****************************************************************************/
/*
* extract the description of a new key from userspace and either add it as a
* new key to the specified keyring or update a matching key in that keyring
* - the keyring must be writable
* - returns the new key's serial number
* - implements add_key()
*/
asmlinkage long sys_add_key(const char __user *_type,
const char __user *_description,
const void __user *_payload,
size_t plen,
key_serial_t ringid)
{
key_ref_t keyring_ref, key_ref;
char type[32], *description;
void *payload;
long dlen, ret;
ret = -EINVAL;
if (plen > 32767)
goto error;
/* draw all the data into kernel space */
ret = strncpy_from_user(type, _type, sizeof(type) - 1);
if (ret < 0)
goto error;
type[31] = '\0';
ret = -EPERM;
if (type[0] == '.')
goto error;
ret = -EFAULT;
dlen = strnlen_user(_description, PAGE_SIZE - 1);
if (dlen <= 0)
goto error;
ret = -EINVAL;
if (dlen > PAGE_SIZE - 1)
goto error;
ret = -ENOMEM;
description = kmalloc(dlen + 1, GFP_KERNEL);
if (!description)
goto error;
ret = -EFAULT;
if (copy_from_user(description, _description, dlen + 1) != 0)
goto error2;
/* pull the payload in if one was supplied */
payload = NULL;
if (_payload) {
ret = -ENOMEM;
payload = kmalloc(plen, GFP_KERNEL);
if (!payload)
goto error2;
ret = -EFAULT;
if (copy_from_user(payload, _payload, plen) != 0)
goto error3;
}
/* find the target keyring (which must be writable) */
keyring_ref = lookup_user_key(NULL, ringid, 1, 0, KEY_WRITE);
if (IS_ERR(keyring_ref)) {
ret = PTR_ERR(keyring_ref);
goto error3;
}
/* create or update the requested key and add it to the target
* keyring */
key_ref = key_create_or_update(keyring_ref, type, description,
payload, plen, 0);
if (!IS_ERR(key_ref)) {
ret = key_ref_to_ptr(key_ref)->serial;
key_ref_put(key_ref);
}
else {
ret = PTR_ERR(key_ref);
}
key_ref_put(keyring_ref);
error3:
kfree(payload);
error2:
kfree(description);
error:
return ret;
} /* end sys_add_key() */
/*****************************************************************************/
/*
* search the process keyrings for a matching key
* - nested keyrings may also be searched if they have Search permission
* - if a key is found, it will be attached to the destination keyring if
* there's one specified
* - /sbin/request-key will be invoked if _callout_info is non-NULL
* - the _callout_info string will be passed to /sbin/request-key
* - if the _callout_info string is empty, it will be rendered as "-"
* - implements request_key()
*/
asmlinkage long sys_request_key(const char __user *_type,
const char __user *_description,
const char __user *_callout_info,
key_serial_t destringid)
{
struct key_type *ktype;
struct key *key;
key_ref_t dest_ref;
char type[32], *description, *callout_info;
long dlen, ret;
/* pull the type into kernel space */
ret = strncpy_from_user(type, _type, sizeof(type) - 1);
if (ret < 0)
goto error;
type[31] = '\0';
ret = -EPERM;
if (type[0] == '.')
goto error;
/* pull the description into kernel space */
ret = -EFAULT;
dlen = strnlen_user(_description, PAGE_SIZE - 1);
if (dlen <= 0)
goto error;
ret = -EINVAL;
if (dlen > PAGE_SIZE - 1)
goto error;
ret = -ENOMEM;
description = kmalloc(dlen + 1, GFP_KERNEL);
if (!description)
goto error;
ret = -EFAULT;
if (copy_from_user(description, _description, dlen + 1) != 0)
goto error2;
/* pull the callout info into kernel space */
callout_info = NULL;
if (_callout_info) {
ret = -EFAULT;
dlen = strnlen_user(_callout_info, PAGE_SIZE - 1);
if (dlen <= 0)
goto error2;
ret = -EINVAL;
if (dlen > PAGE_SIZE - 1)
goto error2;
ret = -ENOMEM;
callout_info = kmalloc(dlen + 1, GFP_KERNEL);
if (!callout_info)
goto error2;
ret = -EFAULT;
if (copy_from_user(callout_info, _callout_info, dlen + 1) != 0)
goto error3;
}
/* get the destination keyring if specified */
dest_ref = NULL;
if (destringid) {
dest_ref = lookup_user_key(NULL, destringid, 1, 0, KEY_WRITE);
if (IS_ERR(dest_ref)) {
ret = PTR_ERR(dest_ref);
goto error3;
}
}
/* find the key type */
ktype = key_type_lookup(type);
if (IS_ERR(ktype)) {
ret = PTR_ERR(ktype);
goto error4;
}
/* do the search */
key = request_key_and_link(ktype, description, callout_info,
key_ref_to_ptr(dest_ref));
if (IS_ERR(key)) {
ret = PTR_ERR(key);
goto error5;
}
ret = key->serial;
key_put(key);
error5:
key_type_put(ktype);
error4:
key_ref_put(dest_ref);
error3:
kfree(callout_info);
error2:
kfree(description);
error:
return ret;
} /* end sys_request_key() */
/*****************************************************************************/
/*
* get the ID of the specified process keyring
* - the keyring must have search permission to be found
* - implements keyctl(KEYCTL_GET_KEYRING_ID)
*/
long keyctl_get_keyring_ID(key_serial_t id, int create)
{
key_ref_t key_ref;
long ret;
key_ref = lookup_user_key(NULL, id, create, 0, KEY_SEARCH);
if (IS_ERR(key_ref)) {
ret = PTR_ERR(key_ref);
goto error;
}
ret = key_ref_to_ptr(key_ref)->serial;
key_ref_put(key_ref);
error:
return ret;
} /* end keyctl_get_keyring_ID() */
/*****************************************************************************/
/*
* join the session keyring
* - implements keyctl(KEYCTL_JOIN_SESSION_KEYRING)
*/
long keyctl_join_session_keyring(const char __user *_name)
{
char *name;
long nlen, ret;
/* fetch the name from userspace */
name = NULL;
if (_name) {
ret = -EFAULT;
nlen = strnlen_user(_name, PAGE_SIZE - 1);
if (nlen <= 0)
goto error;
ret = -EINVAL;
if (nlen > PAGE_SIZE - 1)
goto error;
ret = -ENOMEM;
name = kmalloc(nlen + 1, GFP_KERNEL);
if (!name)
goto error;
ret = -EFAULT;
if (copy_from_user(name, _name, nlen + 1) != 0)
goto error2;
}
/* join the session */
ret = join_session_keyring(name);
error2:
kfree(name);
error:
return ret;
} /* end keyctl_join_session_keyring() */
/*****************************************************************************/
/*
* update a key's data payload
* - the key must be writable
* - implements keyctl(KEYCTL_UPDATE)
*/
long keyctl_update_key(key_serial_t id,
const void __user *_payload,
size_t plen)
{
key_ref_t key_ref;
void *payload;
long ret;
ret = -EINVAL;
if (plen > PAGE_SIZE)
goto error;
/* pull the payload in if one was supplied */
payload = NULL;
if (_payload) {
ret = -ENOMEM;
payload = kmalloc(plen, GFP_KERNEL);
if (!payload)
goto error;
ret = -EFAULT;
if (copy_from_user(payload, _payload, plen) != 0)
goto error2;
}
/* find the target key (which must be writable) */
key_ref = lookup_user_key(NULL, id, 0, 0, KEY_WRITE);
if (IS_ERR(key_ref)) {
ret = PTR_ERR(key_ref);
goto error2;
}
/* update the key */
ret = key_update(key_ref, payload, plen);
key_ref_put(key_ref);
error2:
kfree(payload);
error:
return ret;
} /* end keyctl_update_key() */
/*****************************************************************************/
/*
* revoke a key
* - the key must be writable
* - implements keyctl(KEYCTL_REVOKE)
*/
long keyctl_revoke_key(key_serial_t id)
{
key_ref_t key_ref;
long ret;
key_ref = lookup_user_key(NULL, id, 0, 0, KEY_WRITE);
if (IS_ERR(key_ref)) {
ret = PTR_ERR(key_ref);
goto error;
}
key_revoke(key_ref_to_ptr(key_ref));
ret = 0;
key_ref_put(key_ref);
error:
return ret;
} /* end keyctl_revoke_key() */
/*****************************************************************************/
/*
* clear the specified process keyring
* - the keyring must be writable
* - implements keyctl(KEYCTL_CLEAR)
*/
long keyctl_keyring_clear(key_serial_t ringid)
{
key_ref_t keyring_ref;
long ret;
keyring_ref = lookup_user_key(NULL, ringid, 1, 0, KEY_WRITE);
if (IS_ERR(keyring_ref)) {
ret = PTR_ERR(keyring_ref);
goto error;
}
ret = keyring_clear(key_ref_to_ptr(keyring_ref));
key_ref_put(keyring_ref);
error:
return ret;
} /* end keyctl_keyring_clear() */
/*****************************************************************************/
/*
* link a key into a keyring
* - the keyring must be writable
* - the key must be linkable
* - implements keyctl(KEYCTL_LINK)
*/
long keyctl_keyring_link(key_serial_t id, key_serial_t ringid)
{
key_ref_t keyring_ref, key_ref;
long ret;
keyring_ref = lookup_user_key(NULL, ringid, 1, 0, KEY_WRITE);
if (IS_ERR(keyring_ref)) {
ret = PTR_ERR(keyring_ref);
goto error;
}
key_ref = lookup_user_key(NULL, id, 1, 0, KEY_LINK);
if (IS_ERR(key_ref)) {
ret = PTR_ERR(key_ref);
goto error2;
}
ret = key_link(key_ref_to_ptr(keyring_ref), key_ref_to_ptr(key_ref));
key_ref_put(key_ref);
error2:
key_ref_put(keyring_ref);
error:
return ret;
} /* end keyctl_keyring_link() */
/*****************************************************************************/
/*
* unlink the first attachment of a key from a keyring
* - the keyring must be writable
* - we don't need any permissions on the key
* - implements keyctl(KEYCTL_UNLINK)
*/
long keyctl_keyring_unlink(key_serial_t id, key_serial_t ringid)
{
key_ref_t keyring_ref, key_ref;
long ret;
keyring_ref = lookup_user_key(NULL, ringid, 0, 0, KEY_WRITE);
if (IS_ERR(keyring_ref)) {
ret = PTR_ERR(keyring_ref);
goto error;
}
key_ref = lookup_user_key(NULL, id, 0, 0, 0);
if (IS_ERR(key_ref)) {
ret = PTR_ERR(key_ref);
goto error2;
}
ret = key_unlink(key_ref_to_ptr(keyring_ref), key_ref_to_ptr(key_ref));
key_ref_put(key_ref);
error2:
key_ref_put(keyring_ref);
error:
return ret;
} /* end keyctl_keyring_unlink() */
/*****************************************************************************/
/*
* describe a user key
* - the key must have view permission
* - if there's a buffer, we place up to buflen bytes of data into it
* - unless there's an error, we return the amount of description available,
* irrespective of how much we may have copied
* - the description is formatted thus:
* type;uid;gid;perm;description<NUL>
* - implements keyctl(KEYCTL_DESCRIBE)
*/
long keyctl_describe_key(key_serial_t keyid,
char __user *buffer,
size_t buflen)
{
struct key *key, *instkey;
key_ref_t key_ref;
char *tmpbuf;
long ret;
key_ref = lookup_user_key(NULL, keyid, 0, 1, KEY_VIEW);
if (IS_ERR(key_ref)) {
/* viewing a key under construction is permitted if we have the
* authorisation token handy */
if (PTR_ERR(key_ref) == -EACCES) {
instkey = key_get_instantiation_authkey(keyid);
if (!IS_ERR(instkey)) {
key_put(instkey);
key_ref = lookup_user_key(NULL, keyid,
0, 1, 0);
if (!IS_ERR(key_ref))
goto okay;
}
}
ret = PTR_ERR(key_ref);
goto error;
}
okay:
/* calculate how much description we're going to return */
ret = -ENOMEM;
tmpbuf = kmalloc(PAGE_SIZE, GFP_KERNEL);
if (!tmpbuf)
goto error2;
key = key_ref_to_ptr(key_ref);
ret = snprintf(tmpbuf, PAGE_SIZE - 1,
"%s;%d;%d;%08x;%s",
key_ref_to_ptr(key_ref)->type->name,
key_ref_to_ptr(key_ref)->uid,
key_ref_to_ptr(key_ref)->gid,
key_ref_to_ptr(key_ref)->perm,
key_ref_to_ptr(key_ref)->description ?
key_ref_to_ptr(key_ref)->description : ""
);
/* include a NUL char at the end of the data */
if (ret > PAGE_SIZE - 1)
ret = PAGE_SIZE - 1;
tmpbuf[ret] = 0;
ret++;
/* consider returning the data */
if (buffer && buflen > 0) {
if (buflen > ret)
buflen = ret;
if (copy_to_user(buffer, tmpbuf, buflen) != 0)
ret = -EFAULT;
}
kfree(tmpbuf);
error2:
key_ref_put(key_ref);
error:
return ret;
} /* end keyctl_describe_key() */
/*****************************************************************************/
/*
* search the specified keyring for a matching key
* - the start keyring must be searchable
* - nested keyrings may also be searched if they are searchable
* - only keys with search permission may be found
* - if a key is found, it will be attached to the destination keyring if
* there's one specified
* - implements keyctl(KEYCTL_SEARCH)
*/
long keyctl_keyring_search(key_serial_t ringid,
const char __user *_type,
const char __user *_description,
key_serial_t destringid)
{
struct key_type *ktype;
key_ref_t keyring_ref, key_ref, dest_ref;
char type[32], *description;
long dlen, ret;
/* pull the type and description into kernel space */
ret = strncpy_from_user(type, _type, sizeof(type) - 1);
if (ret < 0)
goto error;
type[31] = '\0';
ret = -EFAULT;
dlen = strnlen_user(_description, PAGE_SIZE - 1);
if (dlen <= 0)
goto error;
ret = -EINVAL;
if (dlen > PAGE_SIZE - 1)
goto error;
ret = -ENOMEM;
description = kmalloc(dlen + 1, GFP_KERNEL);
if (!description)
goto error;
ret = -EFAULT;
if (copy_from_user(description, _description, dlen + 1) != 0)
goto error2;
/* get the keyring at which to begin the search */
keyring_ref = lookup_user_key(NULL, ringid, 0, 0, KEY_SEARCH);
if (IS_ERR(keyring_ref)) {
ret = PTR_ERR(keyring_ref);
goto error2;
}
/* get the destination keyring if specified */
dest_ref = NULL;
if (destringid) {
dest_ref = lookup_user_key(NULL, destringid, 1, 0, KEY_WRITE);
if (IS_ERR(dest_ref)) {
ret = PTR_ERR(dest_ref);
goto error3;
}
}
/* find the key type */
ktype = key_type_lookup(type);
if (IS_ERR(ktype)) {
ret = PTR_ERR(ktype);
goto error4;
}
/* do the search */
key_ref = keyring_search(keyring_ref, ktype, description);
if (IS_ERR(key_ref)) {
ret = PTR_ERR(key_ref);
/* treat lack or presence of a negative key the same */
if (ret == -EAGAIN)
ret = -ENOKEY;
goto error5;
}
/* link the resulting key to the destination keyring if we can */
if (dest_ref) {
ret = key_permission(key_ref, KEY_LINK);
if (ret < 0)
goto error6;
ret = key_link(key_ref_to_ptr(dest_ref), key_ref_to_ptr(key_ref));
if (ret < 0)
goto error6;
}
ret = key_ref_to_ptr(key_ref)->serial;
error6:
key_ref_put(key_ref);
error5:
key_type_put(ktype);
error4:
key_ref_put(dest_ref);
error3:
key_ref_put(keyring_ref);
error2:
kfree(description);
error:
return ret;
} /* end keyctl_keyring_search() */
/*****************************************************************************/
/*
* read a user key's payload
* - the keyring must be readable or the key must be searchable from the
* process's keyrings
* - if there's a buffer, we place up to buflen bytes of data into it
* - unless there's an error, we return the amount of data in the key,
* irrespective of how much we may have copied
* - implements keyctl(KEYCTL_READ)
*/
long keyctl_read_key(key_serial_t keyid, char __user *buffer, size_t buflen)
{
struct key *key;
key_ref_t key_ref;
long ret;
/* find the key first */
key_ref = lookup_user_key(NULL, keyid, 0, 0, 0);
if (IS_ERR(key_ref)) {
ret = -ENOKEY;
goto error;
}
key = key_ref_to_ptr(key_ref);
/* see if we can read it directly */
ret = key_permission(key_ref, KEY_READ);
if (ret == 0)
goto can_read_key;
if (ret != -EACCES)
goto error;
/* we can't; see if it's searchable from this process's keyrings
* - we automatically take account of the fact that it may be
* dangling off an instantiation key
*/
if (!is_key_possessed(key_ref)) {
ret = -EACCES;
goto error2;
}
/* the key is probably readable - now try to read it */
can_read_key:
ret = key_validate(key);
if (ret == 0) {
ret = -EOPNOTSUPP;
if (key->type->read) {
/* read the data with the semaphore held (since we
* might sleep) */
down_read(&key->sem);
ret = key->type->read(key, buffer, buflen);
up_read(&key->sem);
}
}
error2:
key_put(key);
error:
return ret;
} /* end keyctl_read_key() */
/*****************************************************************************/
/*
* change the ownership of a key
* - the keyring owned by the changer
* - if the uid or gid is -1, then that parameter is not changed
* - implements keyctl(KEYCTL_CHOWN)
*/
long keyctl_chown_key(key_serial_t id, uid_t uid, gid_t gid)
{
struct key *key;
key_ref_t key_ref;
long ret;
ret = 0;
if (uid == (uid_t) -1 && gid == (gid_t) -1)
goto error;
key_ref = lookup_user_key(NULL, id, 1, 1, KEY_SETATTR);
if (IS_ERR(key_ref)) {
ret = PTR_ERR(key_ref);
goto error;
}
key = key_ref_to_ptr(key_ref);
/* make the changes with the locks held to prevent chown/chown races */
ret = -EACCES;
down_write(&key->sem);
if (!capable(CAP_SYS_ADMIN)) {
/* only the sysadmin can chown a key to some other UID */
if (uid != (uid_t) -1 && key->uid != uid)
goto no_access;
/* only the sysadmin can set the key's GID to a group other
* than one of those that the current process subscribes to */
if (gid != (gid_t) -1 && gid != key->gid && !in_group_p(gid))
goto no_access;
}
/* change the UID (have to update the quotas) */
if (uid != (uid_t) -1 && uid != key->uid) {
/* don't support UID changing yet */
ret = -EOPNOTSUPP;
goto no_access;
}
/* change the GID */
if (gid != (gid_t) -1)
key->gid = gid;
ret = 0;
no_access:
up_write(&key->sem);
key_put(key);
error:
return ret;
} /* end keyctl_chown_key() */
/*****************************************************************************/
/*
* change the permission mask on a key
* - the keyring owned by the changer
* - implements keyctl(KEYCTL_SETPERM)
*/
long keyctl_setperm_key(key_serial_t id, key_perm_t perm)
{
struct key *key;
key_ref_t key_ref;
long ret;
ret = -EINVAL;
if (perm & ~(KEY_POS_ALL | KEY_USR_ALL | KEY_GRP_ALL | KEY_OTH_ALL))
goto error;
key_ref = lookup_user_key(NULL, id, 1, 1, KEY_SETATTR);
if (IS_ERR(key_ref)) {
ret = PTR_ERR(key_ref);
goto error;
}
key = key_ref_to_ptr(key_ref);
/* make the changes with the locks held to prevent chown/chmod races */
ret = -EACCES;
down_write(&key->sem);
/* if we're not the sysadmin, we can only change a key that we own */
if (capable(CAP_SYS_ADMIN) || key->uid == current->fsuid) {
key->perm = perm;
ret = 0;
}
up_write(&key->sem);
key_put(key);
error:
return ret;
} /* end keyctl_setperm_key() */
/*****************************************************************************/
/*
* instantiate the key with the specified payload, and, if one is given, link
* the key into the keyring
*/
long keyctl_instantiate_key(key_serial_t id,
const void __user *_payload,
size_t plen,
key_serial_t ringid)
{
struct request_key_auth *rka;
struct key *instkey;
key_ref_t keyring_ref;
void *payload;
long ret;
ret = -EINVAL;
if (plen > 32767)
goto error;
/* the appropriate instantiation authorisation key must have been
* assumed before calling this */
ret = -EPERM;
instkey = current->request_key_auth;
if (!instkey)
goto error;
rka = instkey->payload.data;
if (rka->target_key->serial != id)
goto error;
/* pull the payload in if one was supplied */
payload = NULL;
if (_payload) {
ret = -ENOMEM;
payload = kmalloc(plen, GFP_KERNEL);
if (!payload)
goto error;
ret = -EFAULT;
if (copy_from_user(payload, _payload, plen) != 0)
goto error2;
}
/* find the destination keyring amongst those belonging to the
* requesting task */
keyring_ref = NULL;
if (ringid) {
keyring_ref = lookup_user_key(rka->context, ringid, 1, 0,
KEY_WRITE);
if (IS_ERR(keyring_ref)) {
ret = PTR_ERR(keyring_ref);
goto error2;
}
}
/* instantiate the key and link it into a keyring */
ret = key_instantiate_and_link(rka->target_key, payload, plen,
key_ref_to_ptr(keyring_ref), instkey);
key_ref_put(keyring_ref);
/* discard the assumed authority if it's just been disabled by
* instantiation of the key */
if (ret == 0) {
key_put(current->request_key_auth);
current->request_key_auth = NULL;
}
error2:
kfree(payload);
error:
return ret;
} /* end keyctl_instantiate_key() */
/*****************************************************************************/
/*
* negatively instantiate the key with the given timeout (in seconds), and, if
* one is given, link the key into the keyring
*/
long keyctl_negate_key(key_serial_t id, unsigned timeout, key_serial_t ringid)
{
struct request_key_auth *rka;
struct key *instkey;
key_ref_t keyring_ref;
long ret;
/* the appropriate instantiation authorisation key must have been
* assumed before calling this */
ret = -EPERM;
instkey = current->request_key_auth;
if (!instkey)
goto error;
rka = instkey->payload.data;
if (rka->target_key->serial != id)
goto error;
/* find the destination keyring if present (which must also be
* writable) */
keyring_ref = NULL;
if (ringid) {
keyring_ref = lookup_user_key(NULL, ringid, 1, 0, KEY_WRITE);
if (IS_ERR(keyring_ref)) {
ret = PTR_ERR(keyring_ref);
goto error;
}
}
/* instantiate the key and link it into a keyring */
ret = key_negate_and_link(rka->target_key, timeout,
key_ref_to_ptr(keyring_ref), instkey);
key_ref_put(keyring_ref);
/* discard the assumed authority if it's just been disabled by
* instantiation of the key */
if (ret == 0) {
key_put(current->request_key_auth);
current->request_key_auth = NULL;
}
error:
return ret;
} /* end keyctl_negate_key() */
/*****************************************************************************/
/*
* set the default keyring in which request_key() will cache keys
* - return the old setting
*/
long keyctl_set_reqkey_keyring(int reqkey_defl)
{
int ret;
switch (reqkey_defl) {
case KEY_REQKEY_DEFL_THREAD_KEYRING:
ret = install_thread_keyring(current);
if (ret < 0)
return ret;
goto set;
case KEY_REQKEY_DEFL_PROCESS_KEYRING:
ret = install_process_keyring(current);
if (ret < 0)
return ret;
case KEY_REQKEY_DEFL_DEFAULT:
case KEY_REQKEY_DEFL_SESSION_KEYRING:
case KEY_REQKEY_DEFL_USER_KEYRING:
case KEY_REQKEY_DEFL_USER_SESSION_KEYRING:
set:
current->jit_keyring = reqkey_defl;
case KEY_REQKEY_DEFL_NO_CHANGE:
return current->jit_keyring;
case KEY_REQKEY_DEFL_GROUP_KEYRING:
default:
return -EINVAL;
}
} /* end keyctl_set_reqkey_keyring() */
/*****************************************************************************/
/*
* set or clear the timeout for a key
*/
long keyctl_set_timeout(key_serial_t id, unsigned timeout)
{
struct timespec now;
struct key *key;
key_ref_t key_ref;
time_t expiry;
long ret;
key_ref = lookup_user_key(NULL, id, 1, 1, KEY_SETATTR);
if (IS_ERR(key_ref)) {
ret = PTR_ERR(key_ref);
goto error;
}
key = key_ref_to_ptr(key_ref);
/* make the changes with the locks held to prevent races */
down_write(&key->sem);
expiry = 0;
if (timeout > 0) {
now = current_kernel_time();
expiry = now.tv_sec + timeout;
}
key->expiry = expiry;
up_write(&key->sem);
key_put(key);
ret = 0;
error:
return ret;
} /* end keyctl_set_timeout() */
/*****************************************************************************/
/*
* assume the authority to instantiate the specified key
*/
long keyctl_assume_authority(key_serial_t id)
{
struct key *authkey;
long ret;
/* special key IDs aren't permitted */
ret = -EINVAL;
if (id < 0)
goto error;
/* we divest ourselves of authority if given an ID of 0 */
if (id == 0) {
key_put(current->request_key_auth);
current->request_key_auth = NULL;
ret = 0;
goto error;
}
/* attempt to assume the authority temporarily granted to us whilst we
* instantiate the specified key
* - the authorisation key must be in the current task's keyrings
* somewhere
*/
authkey = key_get_instantiation_authkey(id);
if (IS_ERR(authkey)) {
ret = PTR_ERR(authkey);
goto error;
}
key_put(current->request_key_auth);
current->request_key_auth = authkey;
ret = authkey->serial;
error:
return ret;
} /* end keyctl_assume_authority() */
/*****************************************************************************/
/*
* the key control system call
*/
asmlinkage long sys_keyctl(int option, unsigned long arg2, unsigned long arg3,
unsigned long arg4, unsigned long arg5)
{
switch (option) {
case KEYCTL_GET_KEYRING_ID:
return keyctl_get_keyring_ID((key_serial_t) arg2,
(int) arg3);
case KEYCTL_JOIN_SESSION_KEYRING:
return keyctl_join_session_keyring((const char __user *) arg2);
case KEYCTL_UPDATE:
return keyctl_update_key((key_serial_t) arg2,
(const void __user *) arg3,
(size_t) arg4);
case KEYCTL_REVOKE:
return keyctl_revoke_key((key_serial_t) arg2);
case KEYCTL_DESCRIBE:
return keyctl_describe_key((key_serial_t) arg2,
(char __user *) arg3,
(unsigned) arg4);
case KEYCTL_CLEAR:
return keyctl_keyring_clear((key_serial_t) arg2);
case KEYCTL_LINK:
return keyctl_keyring_link((key_serial_t) arg2,
(key_serial_t) arg3);
case KEYCTL_UNLINK:
return keyctl_keyring_unlink((key_serial_t) arg2,
(key_serial_t) arg3);
case KEYCTL_SEARCH:
return keyctl_keyring_search((key_serial_t) arg2,
(const char __user *) arg3,
(const char __user *) arg4,
(key_serial_t) arg5);
case KEYCTL_READ:
return keyctl_read_key((key_serial_t) arg2,
(char __user *) arg3,
(size_t) arg4);
case KEYCTL_CHOWN:
return keyctl_chown_key((key_serial_t) arg2,
(uid_t) arg3,
(gid_t) arg4);
case KEYCTL_SETPERM:
return keyctl_setperm_key((key_serial_t) arg2,
(key_perm_t) arg3);
case KEYCTL_INSTANTIATE:
return keyctl_instantiate_key((key_serial_t) arg2,
(const void __user *) arg3,
(size_t) arg4,
(key_serial_t) arg5);
case KEYCTL_NEGATE:
return keyctl_negate_key((key_serial_t) arg2,
(unsigned) arg3,
(key_serial_t) arg4);
case KEYCTL_SET_REQKEY_KEYRING:
return keyctl_set_reqkey_keyring(arg2);
case KEYCTL_SET_TIMEOUT:
return keyctl_set_timeout((key_serial_t) arg2,
(unsigned) arg3);
case KEYCTL_ASSUME_AUTHORITY:
return keyctl_assume_authority((key_serial_t) arg2);
default:
return -EOPNOTSUPP;
}
} /* end sys_keyctl() */