[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, 11 insertions, 2 deletions

diff --git a/net/socket.c b/net/socket.c
index 6d261bf206fc..6756e57e1ff0 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -973,11 +973,18 @@ int sock_create_lite(int family, int type, int protocol, struct socket **res)
 		goto out;
 	}
 
-	security_socket_post_create(sock, family, type, protocol, 1);
 	sock->type = type;
+	err = security_socket_post_create(sock, family, type, protocol, 1);
+	if (err)
+		goto out_release;
+
 out:
 	*res = sock;
 	return err;
+out_release:
+	sock_release(sock);
+	sock = NULL;
+	goto out;
 }
 
 /* No kernel lock held - perfect */
@@ -1214,7 +1221,9 @@ static int __sock_create(int family, int type, int protocol, struct socket **res
 	 */
 	module_put(net_families[family]->owner);
 	*res = sock;
-	security_socket_post_create(sock, family, type, protocol, kern);
+	err = security_socket_post_create(sock, family, type, protocol, kern);
+	if (err)
+		goto out_release;
 
 out:
 	net_family_read_unlock();