Commit bffd168c authored Apr 14, 2018 by Soheil Hassas Yeganeh Committed by David S. Miller Apr 16, 2018

tcp: clear tp->packets_out when purging write queue



Clear tp->packets_out when purging the write queue, otherwise
tcp_rearm_rto() mistakenly assumes TCP write queue is not empty.
This results in NULL pointer dereference.

Also, remove the redundant `tp->packets_out = 0` from
tcp_disconnect(), since tcp_disconnect() calls
tcp_write_queue_purge().

Fixes: a27fd7a8 (tcp: purge write queue upon RST)
Reported-by: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>
Reported-by: Sami Farin <hvtaifwkbgefbaei@gmail.com>
Tested-by: Sami Farin <hvtaifwkbgefbaei@gmail.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Soheil Hassas Yeganeh <soheil@google.com>
Acked-by: Yuchung Cheng <ycheng@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 4fb0534f

net/ipv4/tcp.c

+1 −1

Original line number	Original line	Diff line number	Diff line
	@@ -2368,6 +2368,7 @@ void tcp_write_queue_purge(struct sock *sk)
	INIT_LIST_HEAD(&tcp_sk(sk)->tsorted_sent_queue);		INIT_LIST_HEAD(&tcp_sk(sk)->tsorted_sent_queue);
	sk_mem_reclaim(sk);		sk_mem_reclaim(sk);
	tcp_clear_all_retrans_hints(tcp_sk(sk));		tcp_clear_all_retrans_hints(tcp_sk(sk));
			tcp_sk(sk)->packets_out = 0;
	}		}

	int tcp_disconnect(struct sock *sk, int flags)		int tcp_disconnect(struct sock *sk, int flags)
	@@ -2417,7 +2418,6 @@ int tcp_disconnect(struct sock *sk, int flags)
	icsk->icsk_backoff = 0;		icsk->icsk_backoff = 0;
	tp->snd_cwnd = 2;		tp->snd_cwnd = 2;
	icsk->icsk_probes_out = 0;		icsk->icsk_probes_out = 0;
	tp->packets_out = 0;
	tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;		tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
	tp->snd_cwnd_cnt = 0;		tp->snd_cwnd_cnt = 0;
	tp->window_clamp = 0;		tp->window_clamp = 0;