[NetLabel]: SELinux support

Add NetLabel support to the SELinux LSM and modify the
socket_post_create() LSM hook to return an error code.  The most
significant part of this patch is the addition of NetLabel hooks into
the following SELinux LSM hooks:

 * selinux_file_permission()
 * selinux_socket_sendmsg()
 * selinux_socket_post_create()
 * selinux_socket_sock_rcv_skb()
 * selinux_socket_getpeersec_stream()
 * selinux_socket_getpeersec_dgram()
 * selinux_sock_graft()
 * selinux_inet_conn_request()

The basic reasoning behind this patch is that outgoing packets are
"NetLabel'd" by labeling their socket and the NetLabel security
attributes are checked via the additional hook in
selinux_socket_sock_rcv_skb().  NetLabel itself is only a labeling
mechanism, similar to filesystem extended attributes, it is up to the
SELinux enforcement mechanism to perform the actual access checks.

In addition to the changes outlined above this patch also includes
some changes to the extended bitmap (ebitmap) and multi-level security
(mls) code to import and export SELinux TE/MLS attributes into and out
of NetLabel.

Signed-off-by: Paul Moore <paul.moore@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 45 insertions, 11 deletions

diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 33028b3..2a6bbb9 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -12,6 +12,8 @@
  *  Copyright (C) 2003 Red Hat, Inc., James Morris <jmorris@redhat.com>
  *  Copyright (C) 2004-2005 Trusted Computer Solutions, Inc.
  *                          <dgoeddel@trustedcs.com>
+ *  Copyright (C) 2006 Hewlett-Packard Development Company, L.P.
+ *                     Paul Moore, <paul.moore@hp.com>
  *
  *	This program is free software; you can redistribute it and/or modify
  *	it under the terms of the GNU General Public License version 2,
@@ -74,6 +76,7 @@
 #include "objsec.h"
 #include "netif.h"
 #include "xfrm.h"
+#include "selinux_netlabel.h"
 
 #define XATTR_SELINUX_SUFFIX "selinux"
 #define XATTR_NAME_SELINUX XATTR_SECURITY_PREFIX XATTR_SELINUX_SUFFIX
@@ -2395,6 +2398,7 @@ static int selinux_inode_listsecurity(struct inode *inode, char *buffer, size_t
 
 static int selinux_file_permission(struct file *file, int mask)
 {
+	int rc;
 	struct inode *inode = file->f_dentry->d_inode;
 
 	if (!mask) {
@@ -2406,8 +2410,12 @@ static int selinux_file_permission(struct file *file, int mask)
 	if ((file->f_flags & O_APPEND) && (mask & MAY_WRITE))
 		mask |= MAY_APPEND;
 
-	return file_has_perm(current, file,
-			     file_mask_to_av(inode->i_mode, mask));
+	rc = file_has_perm(current, file,
+			   file_mask_to_av(inode->i_mode, mask));
+	if (rc)
+		return rc;
+
+	return selinux_netlbl_inode_permission(inode, mask);
 }
 
 static int selinux_file_alloc_security(struct file *file)
@@ -3058,9 +3066,10 @@ out:
 	return err;
 }
 
-static void selinux_socket_post_create(struct socket *sock, int family,
-				       int type, int protocol, int kern)
+static int selinux_socket_post_create(struct socket *sock, int family,
+				      int type, int protocol, int kern)
 {
+	int err = 0;
 	struct inode_security_struct *isec;
 	struct task_security_struct *tsec;
 	struct sk_security_struct *sksec;
@@ -3077,9 +3086,12 @@ static void selinux_socket_post_create(struct socket *sock, int family,
 	if (sock->sk) {
 		sksec = sock->sk->sk_security;
 		sksec->sid = isec->sid;
+		err = selinux_netlbl_socket_post_create(sock,
+							family,
+							isec->sid);
 	}
 
-	return;
+	return err;
 }
 
 /* Range of port numbers used to automatically bind.
@@ -3260,7 +3272,13 @@ static int selinux_socket_accept(struct socket *sock, struct socket *newsock)
 static int selinux_socket_sendmsg(struct socket *sock, struct msghdr *msg,
  				  int size)
 {
-	return socket_has_perm(current, sock, SOCKET__WRITE);
+	int rc;
+
+	rc = socket_has_perm(current, sock, SOCKET__WRITE);
+	if (rc)
+		return rc;
+
+	return selinux_netlbl_inode_permission(SOCK_INODE(sock), MAY_WRITE);
 }
 
 static int selinux_socket_recvmsg(struct socket *sock, struct msghdr *msg,
@@ -3468,6 +3486,10 @@ static int selinux_socket_sock_rcv_skb(struct sock *sk, struct sk_buff *skb)
 	if (err)
 		goto out;
 
+	err = selinux_netlbl_sock_rcv_skb(sksec, skb, &ad);
+	if (err)
+		goto out;
+
 	err = selinux_xfrm_sock_rcv_skb(sksec->sid, skb, &ad);
 out:	
 	return err;
@@ -3491,8 +3513,9 @@ static int selinux_socket_getpeersec_stream(struct socket *sock, char __user *op
 		peer_sid = ssec->peer_sid;
 	}
 	else if (isec->sclass == SECCLASS_TCP_SOCKET) {
-		peer_sid = selinux_socket_getpeer_stream(sock->sk);
-
+		peer_sid = selinux_netlbl_socket_getpeersec_stream(sock);
+		if (peer_sid == SECSID_NULL)
+			peer_sid = selinux_socket_getpeer_stream(sock->sk);
 		if (peer_sid == SECSID_NULL) {
 			err = -ENOPROTOOPT;
 			goto out;
@@ -3532,8 +3555,11 @@ static int selinux_socket_getpeersec_dgram(struct socket *sock, struct sk_buff *
 
 	if (sock && (sock->sk->sk_family == PF_UNIX))
 		selinux_get_inode_sid(SOCK_INODE(sock), &peer_secid);
-	else if (skb)
-		peer_secid = selinux_socket_getpeer_dgram(skb);
+	else if (skb) {
+		peer_secid = selinux_netlbl_socket_getpeersec_dgram(skb);
+		if (peer_secid == SECSID_NULL)
+			peer_secid = selinux_socket_getpeer_dgram(skb);
+	}
 
 	if (peer_secid == SECSID_NULL)
 		err = -EINVAL;
@@ -3578,6 +3604,8 @@ void selinux_sock_graft(struct sock* sk, struct socket *parent)
 	struct sk_security_struct *sksec = sk->sk_security;
 
 	isec->sid = sksec->sid;
+
+	selinux_netlbl_sock_graft(sk, parent);
 }
 
 int selinux_inet_conn_request(struct sock *sk, struct sk_buff *skb,
@@ -3585,9 +3613,15 @@ int selinux_inet_conn_request(struct sock *sk, struct sk_buff *skb,
 {
 	struct sk_security_struct *sksec = sk->sk_security;
 	int err;
-	u32 newsid = 0;
+	u32 newsid;
 	u32 peersid;
 
+	newsid = selinux_netlbl_inet_conn_request(skb, sksec->sid);
+	if (newsid != SECSID_NULL) {
+		req->secid = newsid;
+		return 0;
+	}
+
 	err = selinux_xfrm_decode_session(skb, &peersid, 0);
 	BUG_ON(err);