netdev - Re: [PATCH 0/3][v2] tcp: fix ICMP-RTO war

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]

Message-Id: <20100131.233338.254690877.davem@davemloft.net>
Date:	Sun, 31 Jan 2010 23:33:38 -0800 (PST)
From:	David Miller <davem@...emloft.net>
To:	damian@....rwth-aachen.de
Cc:	netdev@...r.kernel.org
Subject: Re: [PATCH 0/3][v2] tcp: fix ICMP-RTO war

From: Damian Lukowski <damian@....rwth-aachen.de>
Date: Fri, 29 Jan 2010 23:15:51 +0100

> This patches fix the current RTO calculation routine, when
> srtt and rttvar are zero, yielding an RTO of zero 
> Under some circumstances, TCPs srtt and rttvar are zero,
> yielding a calculated RTO of zero.
> This is particularly unfortunate for ICMP based RTO recalculation
> as introduced in f1ecd5d9e736660 (Revert Backoff [v3]: Revert RTO
> on ICMP destination unreachable), as it results in RTO retransmission
> flooding.
> 
> Thanks to Ilpo Jarvinen for providing debug patches and to
> Denys Fedoryshchenko for reporting and testing.
> 
> Signed-off-by: Damian Lukowski <damian@....rwth-aachen.de>

I still haven't seen a detailed enough analysis of why these
tiny RTOs can come to exist in the first place.

Please show me a list of events, function by function, the value of
relevant variables and per-socket TCP state, in the TCP stack, that
show how this ends up happening.

Thanks for all of your work on this so far.
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html