netdev - Re: Question with commit 299b0767(ipv6: Fix IPsec slowpath fragmentation problem)

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: <4F3B57F4.10106@cn.fujitsu.com>
Date:	Wed, 15 Feb 2012 15:00:04 +0800
From:	Li Wei <lw@...fujitsu.com>
To:	Steffen Klassert <steffen.klassert@...unet.com>
CC:	netdev <netdev@...r.kernel.org>
Subject: Re: Question with commit 299b0767(ipv6: Fix IPsec slowpath fragmentation
 problem)

Steffen Klassert wrote:
> On Mon, Feb 13, 2012 at 04:10:39PM +0800, Li Wei wrote:
>> Hi, Steffen!
>>
>> I found some problem while doing networking tests with IPSec that
>> the first fragment doesn't use the max MTU to fill payload, but with
>> 20 bytes smaller. When I reverted your commit 299b0767(ipv6: Fix 
>> IPsec slowpath fragmentation problem), things goes well.
>>
>> Would you so kindly to point me out what the commit did, because I
>> think the original implementation had taken IPSec header and tailer
>> into account.
>>
> 
> Without this patch we used always the slow path in ip6_fragment()
> due to a miscalculation of the packet lenght in ip6_append_data().
> 
> This patch just makes use of the reduced IPsec mtu, and adapts
> the IPsec header handling to have enought headroom on the skb.
> 
> 

Hi Steffen,

Thank you for your reply!

I see in your patch that you use the "mtu" of &rt->dst (which taken IPSec
into account) instead of rt->dst.path, but the "exthdrlen" and "dst_exthdrlen"
things process IPSec again. Does some duplication there?

After reverted the patch and put some "printk" things in the slow_path of
ip6_fragment(), setup IPSec transport mode between two hosts, when sending
some echo request which exceeds the MTU, I don't see any "printk" in slow_path
outputed. Could you tell me how to reproduce the slow_path things?

Thanks,
Wei


--
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