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authorEric Dumazet <edumazet@google.com>2014-11-25 07:40:04 -0800
committerDavid S. Miller <davem@davemloft.net>2014-11-25 14:29:18 -0500
commitc3658e8d0f10147fc86018be7f11668246c156d3 (patch)
treea25e9383d5b91d6062aa4770e6a181e9079d0396
parent43612d7c04f1a4f5e60104143918fcdf018b66ee (diff)
tcp: fix possible NULL dereference in tcp_vX_send_reset()
After commit ca777eff51f7 ("tcp: remove dst refcount false sharing for prequeue mode") we have to relax check against skb dst in tcp_v[46]_send_reset() if prequeue dropped the dst. If a socket is provided, a full lookup was done to find this socket, so the dst test can be skipped. Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=88191 Reported-by: Jaša Bartelj <jasa.bartelj@gmail.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: Daniel Borkmann <dborkman@redhat.com> Fixes: ca777eff51f7 ("tcp: remove dst refcount false sharing for prequeue mode") Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--net/ipv4/tcp_ipv4.c5
-rw-r--r--net/ipv6/tcp_ipv6.c5
2 files changed, 8 insertions, 2 deletions
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 9c7d7621466b..147be2024290 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -598,7 +598,10 @@ static void tcp_v4_send_reset(struct sock *sk, struct sk_buff *skb)
if (th->rst)
return;
- if (skb_rtable(skb)->rt_type != RTN_LOCAL)
+ /* If sk not NULL, it means we did a successful lookup and incoming
+ * route had to be correct. prequeue might have dropped our dst.
+ */
+ if (!sk && skb_rtable(skb)->rt_type != RTN_LOCAL)
return;
/* Swap the send and the receive. */
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index ace29b60813c..dc495ae2ead0 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -903,7 +903,10 @@ static void tcp_v6_send_reset(struct sock *sk, struct sk_buff *skb)
if (th->rst)
return;
- if (!ipv6_unicast_destination(skb))
+ /* If sk not NULL, it means we did a successful lookup and incoming
+ * route had to be correct. prequeue might have dropped our dst.
+ */
+ if (!sk && !ipv6_unicast_destination(skb))
return;
#ifdef CONFIG_TCP_MD5SIG

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