[PATCH] Bluetooth: Fix use after free in l2cap_chan_timeout

[Harish Jenny K N]

There is a potential use after free in bt_sock_poll when a
socket gets killed without getting unlinked from accept_q.
Hence added code to unlink from accpept_q by calling teardown
before freeing the socket for channel type L2CAP_CHAN_CONN_ORIENTED.

Signed-off-by: Harish Jenny K N <harish_kandiga@xxxxxxxxxx>
---
 net/bluetooth/l2cap_core.c |    5 +++++
 1 file changed, 5 insertions(+)

diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
index 6ba33f9..3c3421e 100644
--- a/net/bluetooth/l2cap_core.c
+++ b/net/bluetooth/l2cap_core.c
@@ -415,6 +415,11 @@ static void l2cap_chan_timeout(struct work_struct *work)
 
 	l2cap_chan_close(chan, reason);
 
+	if (((chan->state == BT_CONNECTED) || (chan->state == BT_CONFIG)) &&
+	    chan->chan_type == L2CAP_CHAN_CONN_ORIENTED) {
+		chan->ops->teardown(chan, 0);
+	}
+
 	l2cap_chan_unlock(chan);
 
 	chan->ops->close(chan);
-- 
1.7.9.5

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