netdev - Re: [PATCH net-next] ipv4: tcp: dont cache unconfirmed intput dst

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: <1340860102.26242.203.camel@edumazet-glaptop>
Date:	Thu, 28 Jun 2012 07:08:22 +0200
From:	Eric Dumazet <eric.dumazet@...il.com>
To:	David Miller <davem@...emloft.net>
Cc:	netdev@...r.kernel.org, hans.schillstrom@...csson.com
Subject: Re: [PATCH net-next] ipv4: tcp: dont cache unconfirmed intput dst

On Wed, 2012-06-27 at 17:08 -0700, David Miller wrote:
> From: David Miller <davem@...emloft.net>
> Date: Wed, 27 Jun 2012 17:01:01 -0700 (PDT)
> 
> > There are quite a number of unwanted side effects from this change, so
> > I think we'll have to revert unless you can fix up all of the relevant
> > cases quickly.
> 
> Actually I've decided to revert it now.
> 
> Whilst this was a swell idea, there is no way for you to know if
> we should really create a cached route or not.
> 
> Even if you could, there is a lot of logic you'll need to code up
> so that, f.e., once we determine that we've got a DST_NOCACHE route
> when we move to established state, we can insert it into the routing
> cache and not mark it DST_NOCACHE any longer.
> 
> But even if we did that, we're going to eat 2 uncached route lookups
> for every new incoming legitimate connection.

The initial idea was to perform this only for SYN packets received on a
listener in SYNCOOKIE mode. I'll resend the patch when fully
implemented, instead of a forward patch.

Thanks


--
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