From 70f9d9f3424a0823e42b86d1c5e850d42c6c597c Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Fri, 15 Feb 2019 13:36:21 -0800 Subject: [PATCH] tcp: tcp_v4_err() should be more careful ICMP handlers are not very often stressed, we should make them more resilient to bugs that might surface in the future. If there is no packet in retransmit queue, we should avoid a NULL deref. Signed-off-by: Eric Dumazet Reported-by: soukjin bae Acked-by: Neal Cardwell Acked-by: Soheil Hassas Yeganeh Signed-off-by: David S. Miller --- net/ipv4/tcp_ipv4.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index efc6fef692ffd..ec3cea9d68288 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -536,12 +536,15 @@ int tcp_v4_err(struct sk_buff *icmp_skb, u32 info) if (sock_owned_by_user(sk)) break; + skb = tcp_rtx_queue_head(sk); + if (WARN_ON_ONCE(!skb)) + break; + icsk->icsk_backoff--; icsk->icsk_rto = tp->srtt_us ? __tcp_set_rto(tp) : TCP_TIMEOUT_INIT; icsk->icsk_rto = inet_csk_rto_backoff(icsk, TCP_RTO_MAX); - skb = tcp_rtx_queue_head(sk); tcp_mstamp_refresh(tp); delta_us = (u32)(tp->tcp_mstamp - tcp_skb_timestamp_us(skb)); -- 2.39.5