Commit 32333edb authored Jul 22, 2014 by Vignesh Raman Committed by Marcel Holtmann Jul 22, 2014

Bluetooth: Avoid use of session socket after the session gets freed



The commits 08c30aca "Bluetooth: Remove
RFCOMM session refcnt" and 8ff52f7d
"Bluetooth: Return RFCOMM session ptrs to avoid freed session"
allow rfcomm_recv_ua and rfcomm_session_close to delete the session
(and free the corresponding socket) and propagate NULL session pointer
to the upper callers.

Additional fix is required to terminate the loop in rfcomm_process_rx
function to avoid use of freed 'sk' memory.

The issue is only reproducible with kernel option CONFIG_PAGE_POISONING
enabled making freed memory being changed and filled up with fixed char
value used to unmask use-after-free issues.

Signed-off-by: Vignesh Raman <Vignesh_Raman@mentor.com>
Signed-off-by: Vitaly Kuzmichev <Vitaly_Kuzmichev@mentor.com>
Acked-by: Dean Jenkins <Dean_Jenkins@mentor.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Cc: stable@vger.kernel.org

parent c2aef6e8

net/bluetooth/rfcomm/core.c

+5 −2

Original line number	Diff line number	Diff line
		@@ -1910,11 +1910,14 @@ static struct rfcomm_session rfcomm_process_rx(struct rfcomm_session s)
		/* Get data directly from socket receive queue without copying it. */
		while ((skb = skb_dequeue(&sk->sk_receive_queue))) {
		skb_orphan(skb);
		if (!skb_linearize(skb))
		if (!skb_linearize(skb)) {
		s = rfcomm_recv_frame(s, skb);
		else
		if (!s)
		break;
		} else {
		kfree_skb(skb);
		}
		}

		if (s && (sk->sk_state == BT_CLOSED))
		s = rfcomm_session_close(s, sk->sk_err);