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: v4.2.7~103
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=1ce33c2bcc40c6ccc47fdd35d2afcf8e5c74ba66;p=thirdparty%2Fkernel%2Fstable.git

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 279f83591971b..109e3ee9108c0 100644
--- a/include/net/inet_common.h
+++ b/include/net/inet_common.h
@@ -41,7 +41,8 @@ int inet_recv_error(struct sock *sk, struct msghdr *msg, int len,
 
 static inline void inet_ctl_sock_destroy(struct sock *sk)
 {
-	sock_release(sk->sk_socket);
+	if (sk)
+		sock_release(sk->sk_socket);
 }
 
 #endif