security/selinux/netlabel.c - maze/linux - Git at Google

 /*
  * 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;

 	rc = security_netlbl_sid_to_secattr(sid, &secattr);
 	if (rc != 0)
 		return rc;

 	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);
 	}

 	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;

 	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);
 	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;

 	rc = selinux_netlbl_skbuff_getsid(skb, SECINITSID_NETMSG, &nlbl_sid);
 	if (rc != 0)
 		return rc;
 	if (nlbl_sid == SECSID_NULL)
 		nlbl_sid = SECINITSID_UNLABELED;

 	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;
 }
	/*
	* 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;

	rc = security_netlbl_sid_to_secattr(sid, &secattr);
	if (rc != 0)
	return rc;

	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);
	}

	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;

	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);
	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;

	rc = selinux_netlbl_skbuff_getsid(skb, SECINITSID_NETMSG, &nlbl_sid);
	if (rc != 0)
	return rc;
	if (nlbl_sid == SECSID_NULL)
	nlbl_sid = SECINITSID_UNLABELED;

	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;
	}