From: Eric Dumazet <edumazet@google.com>
Date: Mon, 2 Nov 2015 15:50:07 +0000 (-0800)
Subject: net: avoid NULL deref in inet_ctl_sock_destroy()
X-Git-Tag: v3.10.94~25
X-Git-Url: http://git.hungrycats.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=0861d012ecff07b74a8c6ecfda04bb1737831e09;p=linux

net: avoid NULL deref in inet_ctl_sock_destroy()

[ 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>
---

diff --git a/include/net/inet_common.h b/include/net/inet_common.h
index 234008782c8c..102fc42c7fb1 100644
--- a/include/net/inet_common.h
+++ b/include/net/inet_common.h
@@ -40,7 +40,8 @@ extern int inet_ctl_sock_create(struct sock **sk, unsigned short family,
 
 static inline void inet_ctl_sock_destroy(struct sock *sk)
 {
-	sk_release_kernel(sk);
+	if (sk)
+		sk_release_kernel(sk);
 }
 
 #endif