netdev - Re: [PATCH net-next 1/2] tcp: randomize tcp timestamp offsets for each connection

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:   Tue, 29 Nov 2016 10:06:03 -0800
From:   Eric Dumazet <eric.dumazet@...il.com>
To:     Florian Westphal <fw@...len.de>
Cc:     netdev@...r.kernel.org,
        Mirja Kühlewind 
        <mirja.kuehlewind@....ee.ethz.ch>
Subject: Re: [PATCH net-next 1/2] tcp: randomize tcp timestamp offsets for
 each connection

On Tue, 2016-11-29 at 16:45 +0100, Florian Westphal wrote:
> jiffies based timestamps allow for easy inference of number of devices
> behind NAT translators and also makes tracking of hosts simpler.
> 
> commit ceaa1fef65a7c2e ("tcp: adding a per-socket timestamp offset")
> added the main infrastructure that is needed for per-connection ts
> randomization, in particular writing/reading the on-wire tcp header
> format takes the offset into account so rest of stack can use normal
> tcp_time_stamp (jiffies).
> 
> So only two items are left:
>  - add a tsoffset for request sockets
>  - extend the tcp isn generator to also return another 32bit number
>    in addition to the ISN.
> 
> Re-use of ISN generator also means timestamps are still monotonically
> increasing for same connection quadruple, i.e. PAWS will still work.
> 
> Includes fixes from Eric Dumazet.
> 
> Cc: Mirja Kühlewind <mirja.kuehlewind@....ee.ethz.ch>
> Signed-off-by: Florian Westphal <fw@...len.de>
> ---

Very nice work, thanks !

Acked-by: Eric Dumazet <edumazet@...gle.com>