diff mbox series

[net,1/2] tcp: clear icsk_backoff in tcp_write_queue_purge()

Message ID 20190215213621.183537-2-edumazet@google.com
State Accepted
Delegated to: David Miller
Headers show
Series tcp: fix possible crash in tcp_v4_err() | expand

Commit Message

Eric Dumazet Feb. 15, 2019, 9:36 p.m. UTC 
soukjin bae reported a crash in tcp_v4_err() handling
ICMP_DEST_UNREACH after tcp_write_queue_head(sk)
returned a NULL pointer.

Current logic should have prevented this :

  if (seq != tp->snd_una  || !icsk->icsk_retransmits ||
      !icsk->icsk_backoff || fastopen)
      break;

Problem is the write queue might have been purged
and icsk_backoff has not been cleared.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: soukjin bae <soukjin.bae@samsung.com>
---
 net/ipv4/tcp.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Neal Cardwell Feb. 16, 2019, 2:21 a.m. UTC | #1 
On Fri, Feb 15, 2019 at 4:36 PM Eric Dumazet <edumazet@google.com> wrote:
>
> soukjin bae reported a crash in tcp_v4_err() handling
> ICMP_DEST_UNREACH after tcp_write_queue_head(sk)
> returned a NULL pointer.
>
> Current logic should have prevented this :
>
>   if (seq != tp->snd_una  || !icsk->icsk_retransmits ||
>       !icsk->icsk_backoff || fastopen)
>       break;
>
> Problem is the write queue might have been purged
> and icsk_backoff has not been cleared.
>
> Signed-off-by: Eric Dumazet <edumazet@google.com>
> Reported-by: soukjin bae <soukjin.bae@samsung.com>
> ---
>  net/ipv4/tcp.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

Acked-by: Neal Cardwell <ncardwell@google.com>

Thanks!

neal
diff mbox series

Patch

diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 2079145a3b7c5f498af429c9a8289342e4421fca..cf3c5095c10e8e7e56621beae2f93c93de184489 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -2528,6 +2528,7 @@  void tcp_write_queue_purge(struct sock *sk)
 	sk_mem_reclaim(sk);
 	tcp_clear_all_retrans_hints(tcp_sk(sk));
 	tcp_sk(sk)->packets_out = 0;
+	inet_csk(sk)->icsk_backoff = 0;
 }
 
 int tcp_disconnect(struct sock *sk, int flags)
@@ -2576,7 +2577,6 @@  int tcp_disconnect(struct sock *sk, int flags)
 	tp->write_seq += tp->max_window + 2;
 	if (tp->write_seq == 0)
 		tp->write_seq = 1;
-	icsk->icsk_backoff = 0;
 	tp->snd_cwnd = 2;
 	icsk->icsk_probes_out = 0;
 	tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;