[patch 19/83] ATM: CVE-2008-5079: duplicate listen() on socketcorrupts the vcc table

[Greg KH]

2.6.27-stable review patch.  If anyone has any objections, please let us know.

------------------

From: Chas Williams <chas@xxxxxxxxxxxxxxxx>

commit 17b24b3c97498935a2ef9777370b1151dfed3f6f upstream.

As reported by Hugo Dias that it is possible to cause a local denial
of service attack by calling the svc_listen function twice on the same
socket and reading /proc/net/atm/*vc

Signed-off-by: Chas Williams <chas@xxxxxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

---
 net/atm/svc.c |    6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

--- a/net/atm/svc.c
+++ b/net/atm/svc.c
@@ -293,7 +293,10 @@ static int svc_listen(struct socket *soc
 		error = -EINVAL;
 		goto out;
 	}
-	vcc_insert_socket(sk);
+	if (test_bit(ATM_VF_LISTEN, &vcc->flags)) {
+		error = -EADDRINUSE;
+		goto out;
+        }
 	set_bit(ATM_VF_WAITING, &vcc->flags);
 	prepare_to_wait(sk->sk_sleep, &wait, TASK_UNINTERRUPTIBLE);
 	sigd_enq(vcc,as_listen,NULL,NULL,&vcc->local);
@@ -307,6 +310,7 @@ static int svc_listen(struct socket *soc
 		goto out;
 	}
 	set_bit(ATM_VF_LISTEN,&vcc->flags);
+	vcc_insert_socket(sk);
 	sk->sk_max_ack_backlog = backlog > 0 ? backlog : ATM_BACKLOG_DEFAULT;
 	error = -sk->sk_err;
 out:

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