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  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:	Tue, 02 Dec 2008 09:42:56 -0500
From:	Andrew Gallatin <>
To:	Ben Hutchings <>
CC:	David Miller <>,,,,,,,
Subject: Re: [PATCH] lro: IP fragment checking

Ben Hutchings wrote:
> On Mon, 2008-12-01 at 19:02 -0500, Andrew Gallatin wrote:
>> Ben Hutchings wrote:
>>> On Mon, 2008-12-01 at 16:53 -0500, Andrew Gallatin wrote:
>>>> David Miller wrote:
>>>>> From: Andrew Gallatin <>
>>>>> Date: Mon, 01 Dec 2008 12:50:15 -0500
>>>>>> As to whether or not to do it in the drivers/hardware or in the
>>>>>> LRO code, I favor doing it in the LRO code just so that it is not
>>>>>> missed in some driver.
>>>>> Then there is no point in the hardware doing the check, if
>>>>> we're going to check it anyways.
>>>>> That's part of my point about why this check doesn't belong
>>>>> here.
>>>> What hardware does an explicit check for fragmentation?
>>> Any that implements TCP/UDP checksumming properly.
>> How many do?
> Good question. ;-)
>>>> In most cases, aren't we just relying on the hardware checksum
>>>> to be wrong on fragmented packets? That works 99.999% of the time,
>>>> but the TCP checksum is pretty weak, and it is possible to
>>>> have a fragmented packet where the first fragment has the same
>>>> checksum as the entire packet.
>>> [...]
>>> If your hardware/firmware wrongly claims to be able to verify the
>>> TCP/UDP checksum for an IP fragment, it seems to me you should deal with
>>> that in your driver or fix the firmware.
>> We do partial checksums.
> So you should check for IP fragmentation in your get_frag_header() along
> with all the other checks you've got to do.

Indeed, and that is the patch I intend to submit if the fragment
check in inet_lro is rejected.  I still think the check belongs
in the inet lro code though, and I'm worried it is being rejected
for the wrong reasons..

To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to
More majordomo info at

Powered by blists - more mailing lists