From 37fada67e1a24ae31c4a2717d81b5c311385d288 Mon Sep 17 00:00:00 2001 From: Vignesh Raman Date: Tue, 22 Jul 2014 19:24:25 +0530 Subject: [PATCH] Bluetooth: Avoid use of session socket after the session gets freed commit 32333edb82fb2009980eefc5518100068147ab82 upstream. The commits 08c30aca9e698faddebd34f81e1196295f9dc063 "Bluetooth: Remove RFCOMM session refcnt" and 8ff52f7d04d9cc31f1e81dcf9a2ba6335ed34905 "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 Signed-off-by: Vitaly Kuzmichev Acked-by: Dean Jenkins Signed-off-by: Marcel Holtmann Signed-off-by: Greg Kroah-Hartman --- net/bluetooth/rfcomm/core.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/net/bluetooth/rfcomm/core.c b/net/bluetooth/rfcomm/core.c index facd8a7..b088651 100644 --- a/net/bluetooth/rfcomm/core.c +++ b/net/bluetooth/rfcomm/core.c @@ -1859,10 +1859,13 @@ 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)) -- 2.7.4