[PATCH 3.12 44/72] net: avoid NULL deref in inet_ctl_sock_destroy()

From: Jiri Slaby
Date: Mon Nov 23 2015 - 08:10:14 EST

From: Eric Dumazet <edumazet@xxxxxxxxxx>

3.12-stable review patch. If anyone has any objections, please let me know.


[ 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@xxxxxxxxxx>
Reported-by: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
include/net/inet_common.h | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

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);


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