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authorSoheil Hassas Yeganeh <soheil@google.com>2017-05-15 17:05:47 -0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-06-07 12:05:57 +0200
commit7ede5c90fcdd6d33b3507203e3b8e57b025f34b2 (patch)
tree037f0fc42696e60bc90b560098c78edaf5b401ef /net/ipv4
parentffa551def59c9b0e1747955af6a742443ae152fc (diff)
tcp: eliminate negative reordering in tcp_clean_rtx_queue
[ Upstream commit bafbb9c73241760023d8981191ddd30bb1c6dbac ] tcp_ack() can call tcp_fragment() which may dededuct the value tp->fackets_out when MSS changes. When prior_fackets is larger than tp->fackets_out, tcp_clean_rtx_queue() can invoke tcp_update_reordering() with negative values. This results in absurd tp->reodering values higher than sysctl_tcp_max_reordering. Note that tcp_update_reordering indeeds sets tp->reordering to min(sysctl_tcp_max_reordering, metric), but because the comparison is signed, a negative metric always wins. Fixes: c7caf8d3ed7a ("[TCP]: Fix reord detection due to snd_una covered holes") Reported-by: Rebecca Isaacs <risaacs@google.com> Signed-off-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'net/ipv4')
-rw-r--r--net/ipv4/tcp_input.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 6cb682167c89..87791f803627 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -3220,7 +3220,7 @@ static int tcp_clean_rtx_queue(struct sock *sk, int prior_fackets,
int delta;
/* Non-retransmitted hole got filled? That's reordering */
- if (reord < prior_fackets)
+ if (reord < prior_fackets && reord <= tp->fackets_out)
tcp_update_reordering(sk, tp->fackets_out - reord, 0);
delta = tcp_is_fack(tp) ? pkts_acked :