netdev - Re: [PATCH net-next 6/8] net: gre: Implement LCO for GRE over IPv4

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:	Wed, 20 Jan 2016 19:11:17 +0000
From:	"Rustad, Mark D" <mark.d.rustad@...el.com>
To:	Alexander Duyck <alexander.duyck@...il.com>
CC:	Edward Cree <ecree@...arflare.com>,
	David Laight <David.Laight@...lab.com>,
	David Miller <davem@...emloft.net>,
	"netdev@...r.kernel.org" <netdev@...r.kernel.org>,
	"linux-net-drivers@...arflare.com" <linux-net-drivers@...arflare.com>,
	"tom@...bertland.com" <tom@...bertland.com>
Subject: Re: [PATCH net-next 6/8] net: gre: Implement LCO for GRE over IPv4

Alexander Duyck <alexander.duyck@...il.com> wrote:

> Actually you may want to go the other way on that.  If they weren't
> flipping the checksum value for GRE before why should we start doing
> that now?  I'm pretty sure the checksum mangling is a very UDP centric
> thing.  There is no need to introduce it to other protocols.

If different checksum representations are needed, then there really should  
be an explicit indication of whether it is a UDP-style checksum or other in  
the skb I would think rather than guessing it based on the offset. Of  
course it would be convenient if all the protocols that use a one's  
complement checksum would tolerate the UDP representation. I have a long  
(and now old) history working with real one's complement machines, and so I  
would want to believe that any correct implementation would tolerate it,  
but I don't know for a fact that they do.

--
Mark Rustad, Networking Division, Intel Corporation

Download attachment "signature.asc" of type "application/pgp-signature" (842 bytes)