netdev - [PATCH net-2.6 2/2] [TCP] FRTO: Prevent state inconsistency in corner cases

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Fri, 18 May 2007 12:17:44 +0300 (EEST)
From:	"Ilpo Järvinen" <ilpo.jarvinen@...sinki.fi>
To:	David Miller <davem@...emloft.net>
cc:	Netdev <netdev@...r.kernel.org>
Subject: [PATCH net-2.6 2/2] [TCP] FRTO: Prevent state inconsistency in corner
 cases

State could become inconsistent in two cases:

1) Userspace disabled FRTO by tuning sysctl when one of the TCP
   flows was in the middle of FRTO algorithm (and then RTO is
   again triggered)

2) SACK reneging occurs during FRTO algorithm

A simple solution is just to abort the previous FRTO when such
obscure condition occurs...

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@...sinki.fi>
---
 net/ipv4/tcp_input.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 7ecdc89..38cb25b 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -1501,6 +1501,8 @@ void tcp_enter_loss(struct sock *sk, int how)
 	tcp_set_ca_state(sk, TCP_CA_Loss);
 	tp->high_seq = tp->snd_nxt;
 	TCP_ECN_queue_cwr(tp);
+	/* Abort FRTO algorithm if one is in progress */
+	tp->frto_counter = 0;
 
 	clear_all_retrans_hints(tp);
 }
-- 
1.5.0.6