netdev - [Patch net] bpf: check NULL for sk_to_full

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Date:   Mon, 17 Jul 2017 11:42:55 -0700
From:   Cong Wang <xiyou.wangcong@...il.com>
To:     netdev@...r.kernel.org
Cc:     dsahern@...il.com, Cong Wang <xiyou.wangcong@...il.com>,
        Lawrence Brakmo <brakmo@...com>,
        Daniel Borkmann <daniel@...earbox.net>
Subject: [Patch net] bpf: check NULL for sk_to_full_sk() return value

When req->rsk_listener is NULL, sk_to_full_sk() returns
NULL too, so we have to check its return value against
NULL here.

Fixes: 40304b2a1567 ("bpf: BPF support for sock_ops")
Reported-by: David Ahern <dsahern@...il.com>
Tested-by: David Ahern <dsahern@...il.com>
Cc: Lawrence Brakmo <brakmo@...com>
Cc: Daniel Borkmann <daniel@...earbox.net>
Signed-off-by: Cong Wang <xiyou.wangcong@...il.com>
---
 include/linux/bpf-cgroup.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/bpf-cgroup.h b/include/linux/bpf-cgroup.h
index 360c082e885c..d41d40ac3efd 100644
--- a/include/linux/bpf-cgroup.h
+++ b/include/linux/bpf-cgroup.h
@@ -85,7 +85,7 @@ int __cgroup_bpf_run_filter_sock_ops(struct sock *sk,
 	int __ret = 0;							       \
 	if (cgroup_bpf_enabled && (sock_ops)->sk) {	       \
 		typeof(sk) __sk = sk_to_full_sk((sock_ops)->sk);	       \
-		if (sk_fullsock(__sk))					       \
+		if (__sk && sk_fullsock(__sk))				       \
 			__ret = __cgroup_bpf_run_filter_sock_ops(__sk,	       \
 								 sock_ops,     \
 							 BPF_CGROUP_SOCK_OPS); \
-- 
2.13.0