netdev - Re: [CRIU] TCP_REPAIR MSS issue

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 for Android: free password hash cracker in your pocket

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

Message-ID: <6B535C6E-88BF-4613-816D-7898DB21044C@netapp.com>
Date:	Mon, 18 Jul 2016 09:06:05 +0000
From:	"Eggert, Lars" <lars@...app.com>
To:	Andrey Vagin <avagin@...tuozzo.com>
CC:	Pavel Emelyanov <xemul@...tuozzo.com>,
	"netdev@...r.kernel.org" <netdev@...r.kernel.org>,
	"criu@...nvz.org" <criu@...nvz.org>,
	"Honda, Michio" <michio@...app.com>
Subject: Re: [CRIU] TCP_REPAIR MSS issue

Hi,

On 2016-06-16, at 23:09, Andrey Vagin <avagin@...tuozzo.com> wrote:
> I can't reproduce this issue, now I'm trying to understand why it works
> for me and doesn't work for you.

just to conclude this thread for the list:

Andrey and me debugged this off-list. The issue arose, because my code did a bind() to 0.0.0.0 in TCP_REPAIR mode. When turning off TCP_REPAIR and sending into the socket, this caused minimum-MSS-sized segments to be transmitted. The issue goes away when I bind() to the local IP address of my local egress interface.

To me at least, this is a POLA violation (excuse the FreeBSD terminology :-) Either binding to 0.0.0.0 should fail, or it should succeed and full-sized segments should be sent. But at least I have a work-around now.

Thanks,
Lars

Download attachment "signature.asc" of type "application/pgp-signature" (802 bytes)