irda: Fix memory leak caused by repeated binds of irda socket

The irda_bind() function allocates memory for self->ias_obj without
checking to see if the socket is already bound. A userspace process
could repeatedly bind the socket, have each new object added into the
LM-IAS database, and lose the reference to the old object assigned to
the socket to exhaust memory resources. This patch errors out of the
bind operation when self->ias_obj is already assigned.

CVE-2018-6554

Fixes: 1da177e ("Linux-2.6.12-rc2")
Signed-off-by: Tyler Hicks <[email protected]>
Reviewed-by: Seth Arnold <[email protected]>
Reviewed-by: Stefan Bader <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

Author: tyhicks

drivers/staging/irda/net/af_irda.c

@@ -775,6 +775,13 @@ static int irda_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
 		return -EINVAL;
 
 	lock_sock(sk);
+
+	/* Ensure that the socket is not already bound */
+	if (self->ias_obj) {
+		err = -EINVAL;
+		goto out;
+	}
+
 #ifdef CONFIG_IRDA_ULTRA
 	/* Special care for Ultra sockets */
 	if ((sk->sk_type == SOCK_DGRAM) &&