/*
   * 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"

  #include "netlabel.h"

  
  /**

   * selinux_netlbl_sidlookup_cached - Cache a SID lookup
   * @skb: the packet
   * @secattr: the NetLabel security attributes
   * @sid: the SID
   *
   * Description:
   * Query the SELinux security server to lookup the correct SID for the given
   * security attributes.  If the query is successful, cache the result to speed
   * up future lookups.  Returns zero on success, negative values on failure.
   *
   */
  static int selinux_netlbl_sidlookup_cached(struct sk_buff *skb,
  					   struct netlbl_lsm_secattr *secattr,
  					   u32 *sid)
  {
  	int rc;
  
  	rc = security_netlbl_secattr_to_sid(secattr, sid);
  	if (rc == 0 &&
  	    (secattr->flags & NETLBL_SECATTR_CACHEABLE) &&
  	    (secattr->flags & NETLBL_SECATTR_CACHE))
  		netlbl_cache_add(skb, secattr);
  
  	return rc;
  }
  
  /**

   * 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.

   *
   */

  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)

  		sksec->nlbl_state = NLBL_LABELED;

  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_skbuff_getsid - Get the sid of a packet using NetLabel
   * @skb: the packet

   * @family: protocol family

   * @type: NetLabel labeling protocol type

   * @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,
  				 u16 family,

  				 u32 *type,

  				 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, family, &secattr);

  	if (rc == 0 && secattr.flags != NETLBL_SECATTR_NONE)
  		rc = selinux_netlbl_sidlookup_cached(skb, &secattr, sid);
  	else

  		*sid = SECSID_NULL;

  	*type = secattr.type;

  	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 sk_security_struct *sksec = sk->sk_security;
  	struct netlbl_lsm_secattr secattr;
  	u32 nlbl_peer_sid;

  	if (sksec->nlbl_state != NLBL_REQUIRE)

  		return;

  
  	netlbl_secattr_init(&secattr);
  	if (netlbl_sock_getattr(sk, &secattr) == 0 &&
  	    secattr.flags != NETLBL_SECATTR_NONE &&

  	    security_netlbl_secattr_to_sid(&secattr, &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);

  }
  
  /**
   * 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)
  {

  	struct sock *sk = sock->sk;

  	struct sk_security_struct *sksec = sk->sk_security;

  	if (sksec->nlbl_state != NLBL_REQUIRE)
  		return 0;

  	return selinux_netlbl_sock_setsid(sk, sksec->sid);

  }
  
  /**
   * 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;

  	if (sksec->nlbl_state != NLBL_REQUIRE)

  		return 0;

  	local_bh_disable();

  	bh_lock_sock_nested(sk);

  	if (likely(sksec->nlbl_state == NLBL_REQUIRE))
  		rc = selinux_netlbl_sock_setsid(sk, sksec->sid);
  	else
  		rc = 0;

  	bh_unlock_sock(sk);

  	local_bh_enable();

  
  	return rc;
  }
  
  /**
   * selinux_netlbl_sock_rcv_skb - Do an inbound access check using NetLabel
   * @sksec: the sock's sk_security_struct
   * @skb: the packet

   * @family: protocol family

   * @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,

  				u16 family,

  				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, family, &secattr);

  	if (rc == 0 && secattr.flags != NETLBL_SECATTR_NONE)
  		rc = selinux_netlbl_sidlookup_cached(skb, &secattr, &nlbl_sid);
  	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;

  	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);
  	}

  
  	return rc;
  }