From 2e0158b8812c07f626fe0f94a799875b5ddb142d 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 [ Upstream commit 2c4cc9712364c051b1de2d175d5fbea6be948ebf ] 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 Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman Signed-off-by: Yang Yingliang --- net/ipv4/tcp_ipv4.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index cd426313a298..3b83b157b0a1 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -535,14 +535,15 @@ void 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); - BUG_ON(!skb); - tcp_mstamp_refresh(tp); delta_us = (u32)(tp->tcp_mstamp - skb->skb_mstamp); remaining = icsk->icsk_rto - -- GitLab