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: v4.4-rc1~141^2~1^2~4
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=8fa677d2706d325d71dab91bf6e6512c05214e37;p=thirdparty%2Flinux.git

net: avoid NULL deref in inet_ctl_sock_destroy()

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>
---

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