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  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, 30 Oct 2014 07:30:02 -0700
From:	Alexander Duyck <>
To:	Neal Cardwell <>,
	Pravin Shelar <>
CC:, netdev <>,
	David Miller <>,
	"H.K. Jerry Chu" <>,
	Eric Dumazet <>
Subject: Re: [PATCH net] gre: Fix regression in gretap TSO support

On 10/30/2014 06:51 AM, Neal Cardwell wrote:
> On Thu, Oct 30, 2014 at 1:14 AM, Pravin Shelar <> wrote:
>> On Wed, Oct 29, 2014 at 8:26 PM,  <> wrote:
>>> From: Alexander Duyck <>
>>> On recent kernels I found that TSO on gretap interfaces didn't work.  After
>>> bisecting it I found that commit b884b1a4 had introduced a regression in
>>> which the Ethernet header was being included in the GRE header length.
>>> This change corrects that by basing the GRE header length on the inner mac
>>> header in the case of GRE tunnels using transparent Ethernet bridging, and
>>> uses the network header for all other GRE tunnel types.
>>> Fixes: b884b1a4 ("gre_offload: simplify GRE header length calculation in gre_gso_segment()")
> Hmm. There may be other protocols, either now or in the future, where
> we want to be able to have a mac header inside the GRE header, rather
> than a network header. AFAICT it would be safer to revert b884b1a4,
> and go back to the previous code (from c50cd357), where we parse the
> GRE header to figure out its length.
> neal

The change is consistent with how we handle this in other spots 
throughout the kernel.  If nothing else you can just search for 
ETH_P_TEB and you will find multiple spots in the kernel where IP 
tunnels differentiate between transparent Ethernet bridging and regular 
IP in IP tunnels by checking for the protocol ETH_P_TEB.


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