netdev - Re: [PATCH net-next-2.6] netdev: tilepro: Use is_multicast_ether

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:	Wed, 12 Jan 2011 23:42:50 -0800 (PST)
From:	David Miller <davem@...emloft.net>
To:	tklauser@...tanz.ch
Cc:	cmetcalf@...era.com, netdev@...r.kernel.org
Subject: Re: [PATCH net-next-2.6] netdev: tilepro: Use
 is_multicast_ether_addr helper

From: Tobias Klauser <tklauser@...tanz.ch>
Date: Thu, 13 Jan 2011 07:58:55 +0100

> On 2011-01-13 at 03:45:01 +0100, David Miller <davem@...emloft.net> wrote:
>> From: Chris Metcalf <cmetcalf@...era.com>
>> Date: Wed, 12 Jan 2011 12:49:03 -0500
>> 
>> > On 1/12/2011 4:31 AM, Tobias Klauser wrote:
>> >> Use is_multicast_ether_addr from linux/etherdevice.h instead of a custom
>> >> macro. Also remove the broadcast address check, as it is considered a
>> >> multicast address too.
>> >>
>> >> Signed-off-by: Tobias Klauser <tklauser@...tanz.ch>
>> >> ---
>> >>  drivers/net/tile/tilepro.c |   10 +---------
>> >>  1 files changed, 1 insertions(+), 9 deletions(-)
>> > 
>> > Thanks, I've taken this into the Tilera tree!
>> 
>> Don't, his transformation is buggy.
> 
> Why?
> 
> Doesn't the code want to make sure that only unicast addresses get
> filtered?
> 
>> You can't get rid of the broadcast check, it needs to be there.
>> Think about it.
> 
> If a unicast address is in buf, is_multicast_ether_addr returns false
> (and is_broadcast_addr would too) and thus it would get filtered.

Ok, this may be correct, but it makes the code hard to read.

I think the old code, whilst redundant, is easier to understand.

Why not add a function "is_unicast_ether_addr()" and use that
here instead?

That solves all of the issues I have with your change.
--
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