netdev - Re: [PATCH net] udp: fix bcast packet reception

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]

Date:   Mon, 09 Oct 2017 10:29:18 -0700 (PDT)
From:   David Miller <davem@...emloft.net>
To:     pabeni@...hat.com
Cc:     netdev@...r.kernel.org, hannes@...essinduktion.org
Subject: Re: [PATCH net] udp: fix bcast packet reception

From: Paolo Abeni <pabeni@...hat.com>
Date: Mon,  9 Oct 2017 14:52:10 +0200

> The commit bc044e8db796 ("udp: perform source validation for
> mcast early demux") does not take into account that broadcast packets
> lands in the same code path and they need different checks for the
> source address - notably, zero source address are valid for bcast
> and invalid for mcast.
> 
> As a result, 2nd and later broadcast packets with 0 source address
> landing to the same socket are dropped. This breaks dhcp servers.
> 
> Since we don't have stringent performance requirements for ingress
> broadcast traffic, fix it by disabling UDP early demux such traffic.
> 
> Reported-by: Hannes Frederic Sowa <hannes@...essinduktion.org>
> Fixes: bc044e8db796 ("udp: perform source validation for mcast early demux")
> Signed-off-by: Paolo Abeni <pabeni@...hat.com>

Applied and queued up for -stable.