Patch "net: avoid NULL deref in inet_ctl_sock_destroy()" has been added to the 4.2-stable tree

Patch "net: avoid NULL deref in inet_ctl_sock_destroy()" has been added to the 4.2-stable tree

[gregkh]

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

    net: avoid NULL deref in inet_ctl_sock_destroy()

to the 4.2-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:
     net-avoid-null-deref-in-inet_ctl_sock_destroy.patch
and it can be found in the queue-4.2 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 Tue Nov 17 14:34:38 PST 2015
From: Eric Dumazet <edumazet@google.com>
Date: Mon, 2 Nov 2015 07:50:07 -0800
Subject: net: avoid NULL deref in inet_ctl_sock_destroy()

From: Eric Dumazet <edumazet@google.com>

[ Upstream commit 8fa677d2706d325d71dab91bf6e6512c05214e37 ]

Under low memory conditions, tcp_sk_init() and icmp_sk_init()
can both iterate on all possible cpus and call inet_ctl_sock_destroy(),
with eventual NULL pointer.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 include/net/inet_common.h |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/include/net/inet_common.h
+++ b/include/net/inet_common.h
@@ -41,7 +41,8 @@ int inet_recv_error(struct sock *sk, str
 
 static inline void inet_ctl_sock_destroy(struct sock *sk)
 {
-	sock_release(sk->sk_socket);
+	if (sk)
+		sock_release(sk->sk_socket);
 }
 
 #endif


Patches currently in stable-queue which might be from edumazet@google.com are

queue-4.2/ipv6-gre-support-sit-encapsulation.patch
queue-4.2/ipmr-fix-possible-race-resulting-from-improper-usage-of-ip_inc_stats_bh-in-preemptible-context.patch
queue-4.2/net-avoid-null-deref-in-inet_ctl_sock_destroy.patch
queue-4.2/net-fix-a-race-in-dst_release.patch
queue-4.2/sit-fix-sit0-percpu-double-allocations.patch