appletalk: enforce CAP_NET_RAW for raw sockets

When creating a raw AF_APPLETALK socket, CAP_NET_RAW needs to be checked
first.
Signed-off-by: Ori Nimron <orinimron123@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

CVE-2019-17054

(cherry picked from commit 6cc03e8a)
Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
Acked-by: Seth Forshee <seth.forshee@canonical.com>
Acked-by: Connor Kuehl <connor.kuehl@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

net/appletalk/ddp.c

@@ -1029,6 +1029,11 @@ static int atalk_create(struct net *net, struct socket *sock, int protocol,
 	 */
 	if (sock->type != SOCK_RAW && sock->type != SOCK_DGRAM)
 		goto out;
+
+	rc = -EPERM;
+	if (sock->type == SOCK_RAW && !kern && !capable(CAP_NET_RAW))
+		goto out;
+
 	rc = -ENOMEM;
 	sk = sk_alloc(net, PF_APPLETALK, GFP_KERNEL, &ddp_proto, kern);
 	if (!sk)