netdev - Re: [PATCH net] net/mlx4_en: Force CHECKSUM

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: <977402a5a51b3977fde53d0e8c336f5a8217337e.camel@mellanox.com>
Date:   Fri, 1 Feb 2019 00:05:10 +0000
From:   Saeed Mahameed <saeedm@...lanox.com>
To:     "edumazet@...gle.com" <edumazet@...gle.com>
CC:     Eran Ben Elisha <eranbe@...lanox.com>,
        "davem@...emloft.net" <davem@...emloft.net>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        Tariq Toukan <tariqt@...lanox.com>
Subject: Re: [PATCH net] net/mlx4_en: Force CHECKSUM_NONE for short ethernet
 frames

On Thu, 2019-01-31 at 11:42 -0800, Eric Dumazet wrote:
> On Thu, Jan 31, 2019 at 11:27 AM Saeed Mahameed <saeedm@...lanox.com>
> wrote:
> > Are you sure ? you are claiming that the hardware will skip csum
> > complete i.e cqe->checksum will be 0xffff for padded short IP
> > frames.
> > i don't think this is the case, the whole bug is that the hw does
> > provide a partial cqe->checksum (i.e doesn't included the padding
> > bytes) even for short eth frames.
> 
> If the padding is not included, then cqe->checksum is 0xFFFF for
> correctly received frames.
> 
> Otherwise, what would be cqe->checksum in this case ? A random value
> ?

the actual checksum of IP headers+IP payload, while ignoring the
padding bytes, which is the bug, let me double check..