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Bluetooth: L2CAP ERTM shutdown protect sk and chan

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During execution of l2cap_sock_shutdown() which might
sleep, the sk and chan structures can be in an unlocked
condition which potentially allows the structures to be
freed by other running threads. Therefore, there is a
possibility of a malfunction or memory reuse after being
freed.

Keep the sk and chan structures alive during the
execution of l2cap_sock_shutdown() by using their
respective hold and put functions. This allows the structures
to be freeable at the end of l2cap_sock_shutdown().

Signed-off-by: Kautuk Consul <Kautuk_Consul@mentor.com>
Signed-off-by: Dean Jenkins <Dean_Jenkins@mentor.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
This commit is contained in:
Dean Jenkins 2015-06-23 17:59:32 +01:00 committed by Marcel Holtmann
parent d10270ce94
commit 2baea85dec
1 changed files with 8 additions and 0 deletions
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8
net/bluetooth/l2cap_sock.c
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@ -1098,7 +1098,12 @@ static int l2cap_sock_shutdown(struct socket *sock, int how)
if (!sk)
return 0;
/* prevent sk structure from being freed whilst unlocked */
sock_hold(sk);
chan = l2cap_pi(sk)->chan;
/* prevent chan structure from being freed whilst unlocked */
l2cap_chan_hold(chan);
conn = chan->conn;
BT_DBG("chan %p state %s", chan, state_to_string(chan->state));
@ -1134,6 +1139,9 @@ static int l2cap_sock_shutdown(struct socket *sock, int how)
if (conn)
mutex_unlock(&conn->chan_lock);
l2cap_chan_put(chan);
sock_put(sk);
return err;
}