netdev - Re: [Xen-devel] xennet_start

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:   Thu, 19 Jan 2017 06:14:26 -0500
From:   Sowmini Varadhan <sowmini.varadhan@...cle.com>
To:     Paul Durrant <Paul.Durrant@...rix.com>
Cc:     Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>,
        Wei Liu <wei.liu2@...rix.com>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        "xen-devel@...ts.xenproject.org" <xen-devel@...ts.xenproject.org>
Subject: Re: [Xen-devel] xennet_start_xmit assumptions

On (01/19/17 09:36), Paul Durrant wrote:
> 
> Hi Sowmini,
> 
>   Sounds like a straightforward bug to me... netfront should be able
> to handle an empty skb and clearly, if it's relying on skb_headlen()
> being non-zero, that's not the case.
> 
>   Paul

I see. Seems like there are 2 things broken here: recovering
from skb->len = 0, and recovering from  the more complex
case of (skb->len > 0 && skb_headlen(skb) == 0)

Do you folks want to take a shot at fixing this,
since you know the code better? If you are interested,
I can share my test program to help you reproduce the 
simpler skb->len == 0 case, but it's the fully non-linear
skbs that may be more interesting to reproduce/fix. 

I'll probably work on fixing packet_snd to return -EINVAL 
or similar when the len is zero this week.

--Sowmini