From 5e8c945dc7573ba2f28bddf51ca06b152b4bf749 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Wed, 13 Nov 2013 15:00:46 -0800 Subject: [PATCH] net-tcp: fix panic in tcp_fastopen_cache_set() [ Upstream commit dccf76ca6b626c0c4a4e09bb221adee3270ab0ef ] We had some reports of crashes using TCP fastopen, and Dave Jones gave a nice stack trace pointing to the error. Issue is that tcp_get_metrics() should not be called with a NULL dst Fixes: 1fe4c481ba637 ("net-tcp: Fast Open client - cookie cache") Signed-off-by: Eric Dumazet Reported-by: Dave Jones Cc: Yuchung Cheng Acked-by: Yuchung Cheng Tested-by: Dave Jones Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/ipv4/tcp_metrics.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/net/ipv4/tcp_metrics.c b/net/ipv4/tcp_metrics.c index f6a005c485a9..306dbd9a9441 100644 --- a/net/ipv4/tcp_metrics.c +++ b/net/ipv4/tcp_metrics.c @@ -665,10 +665,13 @@ void tcp_fastopen_cache_get(struct sock *sk, u16 *mss, void tcp_fastopen_cache_set(struct sock *sk, u16 mss, struct tcp_fastopen_cookie *cookie, bool syn_lost) { + struct dst_entry *dst = __sk_dst_get(sk); struct tcp_metrics_block *tm; + if (!dst) + return; rcu_read_lock(); - tm = tcp_get_metrics(sk, __sk_dst_get(sk), true); + tm = tcp_get_metrics(sk, dst, true); if (tm) { struct tcp_fastopen_metrics *tfom = &tm->tcpm_fastopen; -- 2.34.1