linux/net/netlabel/netlabel_unlabeled.c
Paul Moore 4be2700fb7 [NetLabel]: correct usage of RCU locking
This fixes some awkward, and perhaps even problematic, RCU lock usage in the
NetLabel code as well as some other related trivial cleanups found when
looking through the RCU locking.  Most of the changes involve removing the
redundant RCU read locks wrapping spinlocks in the case of a RCU writer.

Signed-off-by: Paul Moore <paul.moore@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-10-26 04:29:08 -07:00

292 lines
7.1 KiB
C

/*
* NetLabel Unlabeled Support
*
* This file defines functions for dealing with unlabeled packets for the
* NetLabel system. The NetLabel system manages static and dynamic label
* mappings for network protocols such as CIPSO and RIPSO.
*
* Author: Paul Moore <paul.moore@hp.com>
*
*/
/*
* (c) Copyright Hewlett-Packard Development Company, L.P., 2006
*
* 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.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
* the GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
*/
#include <linux/types.h>
#include <linux/rcupdate.h>
#include <linux/list.h>
#include <linux/spinlock.h>
#include <linux/socket.h>
#include <linux/string.h>
#include <linux/skbuff.h>
#include <linux/audit.h>
#include <net/sock.h>
#include <net/netlink.h>
#include <net/genetlink.h>
#include <net/netlabel.h>
#include <asm/bug.h>
#include "netlabel_user.h"
#include "netlabel_domainhash.h"
#include "netlabel_unlabeled.h"
/* Accept unlabeled packets flag */
static DEFINE_SPINLOCK(netlabel_unlabel_acceptflg_lock);
static u8 netlabel_unlabel_acceptflg = 0;
/* NetLabel Generic NETLINK CIPSOv4 family */
static struct genl_family netlbl_unlabel_gnl_family = {
.id = GENL_ID_GENERATE,
.hdrsize = 0,
.name = NETLBL_NLTYPE_UNLABELED_NAME,
.version = NETLBL_PROTO_VERSION,
.maxattr = NLBL_UNLABEL_A_MAX,
};
/* NetLabel Netlink attribute policy */
static const struct nla_policy netlbl_unlabel_genl_policy[NLBL_UNLABEL_A_MAX + 1] = {
[NLBL_UNLABEL_A_ACPTFLG] = { .type = NLA_U8 },
};
/*
* Helper Functions
*/
/**
* netlbl_unlabel_acceptflg_set - Set the unlabeled accept flag
* @value: desired value
* @audit_info: NetLabel audit information
*
* Description:
* Set the value of the unlabeled accept flag to @value.
*
*/
static void netlbl_unlabel_acceptflg_set(u8 value,
struct netlbl_audit *audit_info)
{
struct audit_buffer *audit_buf;
u8 old_val;
spin_lock(&netlabel_unlabel_acceptflg_lock);
old_val = netlabel_unlabel_acceptflg;
netlabel_unlabel_acceptflg = value;
spin_unlock(&netlabel_unlabel_acceptflg_lock);
audit_buf = netlbl_audit_start_common(AUDIT_MAC_UNLBL_ALLOW,
audit_info);
if (audit_buf != NULL) {
audit_log_format(audit_buf,
" unlbl_accept=%u old=%u", value, old_val);
audit_log_end(audit_buf);
}
}
/*
* NetLabel Command Handlers
*/
/**
* netlbl_unlabel_accept - Handle an ACCEPT message
* @skb: the NETLINK buffer
* @info: the Generic NETLINK info block
*
* Description:
* Process a user generated ACCEPT message and set the accept flag accordingly.
* Returns zero on success, negative values on failure.
*
*/
static int netlbl_unlabel_accept(struct sk_buff *skb, struct genl_info *info)
{
u8 value;
struct netlbl_audit audit_info;
if (info->attrs[NLBL_UNLABEL_A_ACPTFLG]) {
value = nla_get_u8(info->attrs[NLBL_UNLABEL_A_ACPTFLG]);
if (value == 1 || value == 0) {
netlbl_netlink_auditinfo(skb, &audit_info);
netlbl_unlabel_acceptflg_set(value, &audit_info);
return 0;
}
}
return -EINVAL;
}
/**
* netlbl_unlabel_list - Handle a LIST message
* @skb: the NETLINK buffer
* @info: the Generic NETLINK info block
*
* Description:
* Process a user generated LIST message and respond with the current status.
* Returns zero on success, negative values on failure.
*
*/
static int netlbl_unlabel_list(struct sk_buff *skb, struct genl_info *info)
{
int ret_val = -EINVAL;
struct sk_buff *ans_skb;
void *data;
ans_skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
if (ans_skb == NULL)
goto list_failure;
data = genlmsg_put_reply(ans_skb, info, &netlbl_unlabel_gnl_family,
0, NLBL_UNLABEL_C_LIST);
if (data == NULL) {
ret_val = -ENOMEM;
goto list_failure;
}
rcu_read_lock();
ret_val = nla_put_u8(ans_skb,
NLBL_UNLABEL_A_ACPTFLG,
netlabel_unlabel_acceptflg);
rcu_read_unlock();
if (ret_val != 0)
goto list_failure;
genlmsg_end(ans_skb, data);
ret_val = genlmsg_reply(ans_skb, info);
if (ret_val != 0)
goto list_failure;
return 0;
list_failure:
kfree_skb(ans_skb);
return ret_val;
}
/*
* NetLabel Generic NETLINK Command Definitions
*/
static struct genl_ops netlbl_unlabel_genl_c_accept = {
.cmd = NLBL_UNLABEL_C_ACCEPT,
.flags = GENL_ADMIN_PERM,
.policy = netlbl_unlabel_genl_policy,
.doit = netlbl_unlabel_accept,
.dumpit = NULL,
};
static struct genl_ops netlbl_unlabel_genl_c_list = {
.cmd = NLBL_UNLABEL_C_LIST,
.flags = 0,
.policy = netlbl_unlabel_genl_policy,
.doit = netlbl_unlabel_list,
.dumpit = NULL,
};
/*
* NetLabel Generic NETLINK Protocol Functions
*/
/**
* netlbl_unlabel_genl_init - Register the Unlabeled NetLabel component
*
* Description:
* Register the unlabeled packet NetLabel component with the Generic NETLINK
* mechanism. Returns zero on success, negative values on failure.
*
*/
int netlbl_unlabel_genl_init(void)
{
int ret_val;
ret_val = genl_register_family(&netlbl_unlabel_gnl_family);
if (ret_val != 0)
return ret_val;
ret_val = genl_register_ops(&netlbl_unlabel_gnl_family,
&netlbl_unlabel_genl_c_accept);
if (ret_val != 0)
return ret_val;
ret_val = genl_register_ops(&netlbl_unlabel_gnl_family,
&netlbl_unlabel_genl_c_list);
if (ret_val != 0)
return ret_val;
return 0;
}
/*
* NetLabel KAPI Hooks
*/
/**
* netlbl_unlabel_getattr - Get the security attributes for an unlabled packet
* @secattr: the security attributes
*
* Description:
* Determine the security attributes, if any, for an unlabled packet and return
* them in @secattr. Returns zero on success and negative values on failure.
*
*/
int netlbl_unlabel_getattr(struct netlbl_lsm_secattr *secattr)
{
int ret_val;
rcu_read_lock();
if (netlabel_unlabel_acceptflg == 1) {
netlbl_secattr_init(secattr);
ret_val = 0;
} else
ret_val = -ENOMSG;
rcu_read_unlock();
return ret_val;
}
/**
* netlbl_unlabel_defconf - Set the default config to allow unlabeled packets
*
* Description:
* Set the default NetLabel configuration to allow incoming unlabeled packets
* and to send unlabeled network traffic by default.
*
*/
int netlbl_unlabel_defconf(void)
{
int ret_val;
struct netlbl_dom_map *entry;
struct netlbl_audit audit_info;
/* Only the kernel is allowed to call this function and the only time
* it is called is at bootup before the audit subsystem is reporting
* messages so don't worry to much about these values. */
security_task_getsecid(current, &audit_info.secid);
audit_info.loginuid = 0;
entry = kzalloc(sizeof(*entry), GFP_KERNEL);
if (entry == NULL)
return -ENOMEM;
entry->type = NETLBL_NLTYPE_UNLABELED;
ret_val = netlbl_domhsh_add_default(entry, &audit_info);
if (ret_val != 0)
return ret_val;
netlbl_unlabel_acceptflg_set(1, &audit_info);
return 0;
}