linux-kernel - Re: [PATCH net] Bridge: Fix ipv6 mc snooping if bridge has no ipv6 address

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: <20160628.054848.470650145752210386.davem@davemloft.net>
Date:	Tue, 28 Jun 2016 05:48:48 -0400 (EDT)
From:	David Miller <davem@...emloft.net>
To:	daniel@...wrt.com
Cc:	bridge@...ts.linux-foundation.org, netdev@...r.kernel.org,
	linux-kernel@...r.kernel.org, stephen@...workplumber.org,
	linus.luessing@...3.blue
Subject: Re: [PATCH net] Bridge: Fix ipv6 mc snooping if bridge has no ipv6
 address

From: Daniel Danzberger <daniel@...wrt.com>
Date: Fri, 24 Jun 2016 12:35:18 +0200

> The bridge is falsly dropping ipv6 mulitcast packets if there is:
>  1. No ipv6 address assigned on the brigde.
>  2. No external mld querier present.
>  3. The internal querier enabled.
> 
> When the bridge fails to build mld queries, because it has no
> ipv6 address, it slilently returns, but keeps the local querier enabled.
> This specific case causes confusing packet loss.
> 
> Ipv6 multicast snooping can only work if:
>  a) An external querier is present
>  OR
>  b) The bridge has an ipv6 address an is capable of sending own queries
> 
> Otherwise it has to forward/flood the ipv6 multicast traffic,
> because snooping cannot work.
> 
> This patch fixes the issue by adding a flag to the bridge struct that
> indicates that there is currently no ipv6 address assinged to the bridge
> and returns a false state for the local querier in
> __br_multicast_querier_exists().
> 
> Special thanks to Linus Lüssing.
> 
> Signed-off-by: Daniel Danzberger <daniel@...wrt.com>

Applied.