/*
* SELinux NetLabel Support
*
* This file provides the necessary glue to tie NetLabel into the SELinux
* subsystem.
*
* Author: Paul Moore <paul.moore@hp.com>
*
*/
/*
* (c) Copyright Hewlett-Packard Development Company, L.P., 2007
*
* 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/spinlock.h>
#include <linux/rcupdate.h>
#include <net/sock.h>
#include <net/netlabel.h>
#include "objsec.h"
#include "security.h"
/**
* selinux_netlbl_sock_setsid - Label a socket using the NetLabel mechanism
* @sk: the socket to label
* @sid: the SID to use
*
* Description:
* Attempt to label a socket using the NetLabel mechanism using the given
* SID. Returns zero values on success, negative values on failure. The
* caller is responsibile for calling rcu_read_lock() before calling this
* this function and rcu_read_unlock() after this function returns.
*
*/
static int selinux_netlbl_sock_setsid(struct sock *sk, u32 sid)
{
int rc;
struct sk_security_struct *sksec = sk->sk_security;
struct netlbl_lsm_secattr secattr;
netlbl_secattr_init(&secattr);
rc = security_netlbl_sid_to_secattr(sid, &secattr);
if (rc != 0)
goto sock_setsid_return;
rc = netlbl_sock_setattr(sk, &secattr);
if (rc == 0) {
spin_lock_bh(&sksec->nlbl_lock);
sksec->nlbl_state = NLBL_LABELED;
spin_unlock_bh(&sksec->nlbl_lock);
}
sock_setsid_return:
netlbl_secattr_destroy(&secattr);
return rc;
}
/**
* selinux_netlbl_cache_invalidate - Invalidate the NetLabel cache
*
* Description:
* Invalidate the NetLabel security attribute mapping cache.
*
*/
void selinux_netlbl_cache_invalidate(void)
{
netlbl_cache_invalidate();
}
/**
* selinux_netlbl_sk_security_reset - Reset the NetLabel fields
* @ssec: the sk_security_struct
* @family: the socket family
*
* Description:
* Called when the NetLabel state of a sk_security_struct needs to be reset.
* The caller is responsibile for all the NetLabel sk_security_struct locking.
*
*/
void selinux_netlbl_sk_security_reset(struct sk_security_struct *ssec,
int family)
{
if (family == PF_INET)
ssec->nlbl_state = NLBL_REQUIRE;
else
ssec->nlbl_state = NLBL_UNSET;
}
/**
* selinux_netlbl_sk_security_init - Setup the NetLabel fields
* @ssec: the sk_security_struct
* @family: the socket family
*
* Description:
* Called when a new sk_security_struct is allocated to initialize the NetLabel
* fields.
*
*/
void selinux_netlbl_sk_security_init(struct sk_security_struct *ssec,
int family)
{
/* No locking needed, we are the only one who has access to ssec */
selinux_netlbl_sk_security_reset(ssec, family);
spin_lock_init(&ssec->nlbl_lock);
}
/**
* selinux_netlbl_sk_security_clone - Copy the NetLabel fields
* @ssec: the original sk_security_struct
* @newssec: the cloned sk_security_struct
*
* Description:
* Clone the NetLabel specific sk_security_struct fields from @ssec to
* @newssec.
*
*/
void selinux_netlbl_sk_security_clone(struct sk_security_struct *ssec,
struct sk_security_struct *newssec)
{
/* We don't need to take newssec->nlbl_lock because we are the only
* thread with access to newssec, but we do need to take the RCU read
* lock as other threads could have access to ssec */
rcu_read_lock();
selinux_netlbl_sk_security_reset(newssec, ssec->sk->sk_family);
newssec->sclass = ssec->sclass;
rcu_read_unlock();
}
/**
* selinux_netlbl_skbuff_getsid - Get the sid of a packet using NetLabel
* @skb: the packet
* @base_sid: the SELinux SID to use as a context for MLS only attributes
* @sid: the SID
*
* Description:
* Call the NetLabel mechanism to get the security attributes of the given
* packet and use those attributes to determine the correct context/SID to
* assign to the packet. Returns zero on success, negative values on failure.
*
*/
int selinux_netlbl_skbuff_getsid(struct sk_buff *skb, u32 base_sid, u32 *sid)
{
int rc;
struct netlbl_lsm_secattr secattr;
if (!netlbl_enabled()) {
*sid = SECSID_NULL;
return 0;
}
netlbl_secattr_init(&secattr);
rc = netlbl_skbuff_getattr(skb, &secattr);
if (rc == 0 && secattr.flags != NETLBL_SECATTR_NONE) {
rc = security_netlbl_secattr_to_sid(&secattr, base_sid, sid);
if (rc == 0 &&
(secattr.flags & NETLBL_SECATTR_CACHEABLE) &&
(secattr.flags & NETLBL_SECATTR_CACHE))
netlbl_cache_add(skb, &secattr);
} else
*sid = SECSID_NULL;
netlbl_secattr_destroy(&secattr);
return rc;
}
/**
* selinux_netlbl_sock_graft - Netlabel the new socket
* @sk: the new connection
* @sock: the new socket
*
* Description:
* The connection represented by @sk is being grafted onto @sock so set the
* socket's NetLabel to match the SID of @sk.
*
*/
void selinux_netlbl_sock_graft(struct sock *sk, struct socket *sock)
{
struct inode_security_struct *isec = SOCK_INODE(sock)->i_security;
struct sk_security_struct *sksec = sk->sk_security;
struct netlbl_lsm_secattr secattr;
u32 nlbl_peer_sid;
sksec->sclass = isec->sclass;
rcu_read_lock();
if (sksec->nlbl_state != NLBL_REQUIRE) {
rcu_read_unlock();
return;
}
netlbl_secattr_init(&secattr);
if (netlbl_sock_getattr(sk, &secattr) == 0 &&
secattr.flags != NETLBL_SECATTR_NONE &&
security_netlbl_secattr_to_sid(&secattr,
SECINITSID_NETMSG,
&nlbl_peer_sid) == 0)
sksec->peer_sid = nlbl_peer_sid;
netlbl_secattr_destroy(&secattr);
/* Try to set the NetLabel on the socket to save time later, if we fail
* here we will pick up the pieces in later calls to
* selinux_netlbl_inode_permission(). */
selinux_netlbl_sock_setsid(sk, sksec->sid);
rcu_read_unlock();
}
/**
* selinux_netlbl_socket_post_create - Label a socket using NetLabel
* @sock: the socket to label
*
* Description:
* Attempt to label a socket using the NetLabel mechanism using the given
* SID. Returns zero values on success, negative values on failure.
*
*/
int selinux_netlbl_socket_post_create(struct socket *sock)
{
int rc = 0;
struct sock *sk = sock->sk;
struct inode_security_struct *isec = SOCK_INODE(sock)->i_security;
struct sk_security_struct *sksec = sk->sk_security;
sksec->sclass = isec->sclass;
rcu_read_lock();
if (sksec->nlbl_state == NLBL_REQUIRE)
rc = selinux_netlbl_sock_setsid(sk, sksec->sid);
rcu_read_unlock();
return rc;
}
/**
* selinux_netlbl_inode_permission - Verify the socket is NetLabel labeled
* @inode: the file descriptor's inode
* @mask: the permission mask
*
* Description:
* Looks at a file's inode and if it is marked as a socket protected by
* NetLabel then verify that the socket has been labeled, if not try to label
* the socket now with the inode's SID. Returns zero on success, negative
* values on failure.
*
*/
int selinux_netlbl_inode_permission(struct inode *inode, int mask)
{
int rc;
struct sock *sk;
struct socket *sock;
struct sk_security_struct *sksec;
if (!S_ISSOCK(inode->i_mode) ||
((mask & (MAY_WRITE | MAY_APPEND)) == 0))
return 0;
sock = SOCKET_I(inode);
sk = sock->sk;
sksec = sk->sk_security;
rcu_read_lock();
if (sksec->nlbl_state != NLBL_REQUIRE) {
rcu_read_unlock();
return 0;
}
local_bh_disable();
bh_lock_sock_nested(sk);
rc = selinux_netlbl_sock_setsid(sk, sksec->sid);
bh_unlock_sock(sk);
local_bh_enable();
rcu_read_unlock();
return rc;
}
/**
* selinux_netlbl_sock_rcv_skb - Do an inbound access check using NetLabel
* @sksec: the sock's sk_security_struct
* @skb: the packet
* @ad: the audit data
*
* Description:
* Fetch the NetLabel security attributes from @skb and perform an access check
* against the receiving socket. Returns zero on success, negative values on
* error.
*
*/
int selinux_netlbl_sock_rcv_skb(struct sk_security_struct *sksec,
struct sk_buff *skb,
struct avc_audit_data *ad)
{
int rc;
u32 nlbl_sid;
u32 perm;
struct netlbl_lsm_secattr secattr;
if (!netlbl_enabled())
return 0;
netlbl_secattr_init(&secattr);
rc = netlbl_skbuff_getattr(skb, &secattr);
if (rc == 0 && secattr.flags != NETLBL_SECATTR_NONE) {
rc = security_netlbl_secattr_to_sid(&secattr,
SECINITSID_NETMSG,
&nlbl_sid);
if (rc == 0 &&
(secattr.flags & NETLBL_SECATTR_CACHEABLE) &&
(secattr.flags & NETLBL_SECATTR_CACHE))
netlbl_cache_add(skb, &secattr);
} else
nlbl_sid = SECINITSID_UNLABELED;
netlbl_secattr_destroy(&secattr);
if (rc != 0)
return rc;
switch (sksec->sclass) {
case SECCLASS_UDP_SOCKET:
perm = UDP_SOCKET__RECVFROM;
break;
case SECCLASS_TCP_SOCKET:
perm = TCP_SOCKET__RECVFROM;
break;
default:
perm = RAWIP_SOCKET__RECVFROM;
}
rc = avc_has_perm(sksec->sid, nlbl_sid, sksec->sclass, perm, ad);
if (rc == 0)
return 0;
if (nlbl_sid != SECINITSID_UNLABELED)
netlbl_skbuff_err(skb, rc);
return rc;
}
/**
* selinux_netlbl_socket_setsockopt - Do not allow users to remove a NetLabel
* @sock: the socket
* @level: the socket level or protocol
* @optname: the socket option name
*
* Description:
* Check the setsockopt() call and if the user is trying to replace the IP
* options on a socket and a NetLabel is in place for the socket deny the
* access; otherwise allow the access. Returns zero when the access is
* allowed, -EACCES when denied, and other negative values on error.
*
*/
int selinux_netlbl_socket_setsockopt(struct socket *sock,
int level,
int optname)
{
int rc = 0;
struct sock *sk = sock->sk;
struct sk_security_struct *sksec = sk->sk_security;
struct netlbl_lsm_secattr secattr;
rcu_read_lock();
if (level == IPPROTO_IP && optname == IP_OPTIONS &&
sksec->nlbl_state == NLBL_LABELED) {
netlbl_secattr_init(&secattr);
lock_sock(sk);
rc = netlbl_sock_getattr(sk, &secattr);
release_sock(sk);
if (rc == 0 && secattr.flags != NETLBL_SECATTR_NONE)
rc = -EACCES;
netlbl_secattr_destroy(&secattr);
}
rcu_read_unlock();
return rc;
}
