Patch "ax25: Fix segfault after sock connection timeout" has been added to the 4.4-stable tree

Patch "ax25: Fix segfault after sock connection timeout" has been added to the 4.4-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    ax25: Fix segfault after sock connection timeout

to the 4.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     ax25-fix-segfault-after-sock-connection-timeout.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From foo@baz Wed Feb  1 08:49:51 CET 2017
From: Basil Gunn <basil@pacabunga.com>
Date: Sat, 14 Jan 2017 12:18:55 -0800
Subject: ax25: Fix segfault after sock connection timeout

From: Basil Gunn <basil@pacabunga.com>


[ Upstream commit 8a367e74c0120ef68c8c70d5a025648c96626dff ]

The ax.25 socket connection timed out & the sock struct has been
previously taken down ie. sock struct is now a NULL pointer. Checking
the sock_flag causes the segfault.  Check if the socket struct pointer
is NULL before checking sock_flag. This segfault is seen in
timed out netrom connections.

Please submit to -stable.

Signed-off-by: Basil Gunn <basil@pacabunga.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 net/ax25/ax25_subr.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/net/ax25/ax25_subr.c
+++ b/net/ax25/ax25_subr.c
@@ -264,7 +264,7 @@ void ax25_disconnect(ax25_cb *ax25, int
 {
 	ax25_clear_queues(ax25);
 
-	if (!sock_flag(ax25->sk, SOCK_DESTROY))
+	if (!ax25->sk || !sock_flag(ax25->sk, SOCK_DESTROY))
 		ax25_stop_heartbeat(ax25);
 	ax25_stop_t1timer(ax25);
 	ax25_stop_t2timer(ax25);


Patches currently in stable-queue which might be from basil@pacabunga.com are

queue-4.4/ax25-fix-segfault-after-sock-connection-timeout.patch