[PATCH 3.19.y-ckt 016/164] net: avoid NULL deref in inet_ctl_sock_destroy()

From: Kamal Mostafa
Date: Wed Dec 02 2015 - 12:59:49 EST


3.19.8-ckt11 -stable review patch. If anyone has any objections, please let me know.

------------------

From: Eric Dumazet <edumazet@xxxxxxxxxx>

[ 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: Kamal Mostafa <kamal@xxxxxxxxxxxxx>
---
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 b2828a0..a7d812d 100644
--- a/include/net/inet_common.h
+++ b/include/net/inet_common.h
@@ -42,7 +42,8 @@ int inet_recv_error(struct sock *sk, struct msghdr *msg, int len,

static inline void inet_ctl_sock_destroy(struct sock *sk)
{
- sk_release_kernel(sk);
+ if (sk)
+ sk_release_kernel(sk);
}

#endif
--
1.9.1

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