netdev - Re: [PATCH net v2] netfilter: nat: cope with negative port range

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: <20180214135119.vmfw2jraieo3zxdg@salvia>
Date:   Wed, 14 Feb 2018 14:51:19 +0100
From:   Pablo Neira Ayuso <pablo@...filter.org>
To:     Florian Westphal <fw@...len.de>
Cc:     Eric Dumazet <eric.dumazet@...il.com>,
        Paolo Abeni <pabeni@...hat.com>, netdev@...r.kernel.org,
        "David S. Miller" <davem@...emloft.net>,
        netfilter-devel@...r.kernel.org, syzkaller-bugs@...glegroups.com
Subject: Re: [PATCH net v2] netfilter: nat: cope with negative port range

On Wed, Feb 14, 2018 at 01:30:37PM +0100, Florian Westphal wrote:
> Eric Dumazet <eric.dumazet@...il.com> wrote:
> > On Wed, 2018-02-14 at 12:13 +0100, Paolo Abeni wrote:
> > > syzbot reported a division by 0 bug in the netfilter nat code:
> > 
> > > Adding the relevant check at parse time could break existing
> > > setup, moreover we would need to read/write such values atomically
> > > to avoid possible transient negative ranges at update time.
> > 
> > I do not quite follow why it is so hard to add a check at parse time.
> > 
> > Breaking buggy setups would not be a concern I think.
> 
> It would be possible for xtables but afaics in nft_nat.c case
> (nft_nat_eval) range.{min,max}_proto.all values are loaded from nft
> registers at runtime.

Then, restrict this from nft_nat.