Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S936274AbcLWMAN (ORCPT ); Fri, 23 Dec 2016 07:00:13 -0500 Received: from www62.your-server.de ([213.133.104.62]:36311 "EHLO www62.your-server.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932873AbcLWMAM (ORCPT ); Fri, 23 Dec 2016 07:00:12 -0500 Message-ID: <585D11BF.60903@iogearbox.net> Date: Fri, 23 Dec 2016 12:59:59 +0100 From: Daniel Borkmann User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.7.0 MIME-Version: 1.0 To: Hannes Frederic Sowa , Andy Lutomirski , Alexei Starovoitov CC: "Jason A. Donenfeld" , "kernel-hardening@lists.openwall.com" , "Theodore Ts'o" , Netdev , LKML , Linux Crypto Mailing List , David Laight , Eric Dumazet , Linus Torvalds , Eric Biggers , Tom Herbert , Andi Kleen , "David S. Miller" , Jean-Philippe Aumasson Subject: Re: BPF hash algo (Re: [kernel-hardening] Re: [PATCH v7 3/6] random: use SipHash in place of MD5) References: <1482425969.2673.5.camel@stressinduktion.org> <585CF6A3.1050107@iogearbox.net> <1482490762.3353.2.camel@stressinduktion.org> In-Reply-To: <1482490762.3353.2.camel@stressinduktion.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit X-Authenticated-Sender: daniel@iogearbox.net Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2025 Lines: 40 On 12/23/2016 11:59 AM, Hannes Frederic Sowa wrote: > On Fri, 2016-12-23 at 11:04 +0100, Daniel Borkmann wrote: >> On 12/22/2016 05:59 PM, Hannes Frederic Sowa wrote: >>> On Thu, 2016-12-22 at 08:07 -0800, Andy Lutomirski wrote: [...] >>> The hashing is not a proper sha1 neither, unfortunately. I think that >>> is why it will have a custom implementation in iproute2? >> >> Still trying to catch up on this admittedly bit confusing thread. I >> did run automated tests over couple of days comparing the data I got >> from fdinfo with the one from af_alg and found no mismatch on the test >> cases varying from min to max possible program sizes. In the process >> of testing, as you might have seen on netdev, I found couple of other >> bugs in bpf code along the way and fixed them up as well. So my question, >> do you or Andy or anyone participating in claiming this have any >> concrete data or test cases that suggests something different? If yes, >> I'm very curious to hear about it and willing fix it up, of course. >> When I'm back from pto I'll prep and cook up my test suite to be >> included into the selftests/bpf/, should have done this initially, >> sorry about that. I'll also post something to expose the alg, that >> sounds fine to me. > > Looking into your code closer, I noticed that you indeed seem to do the > finalization of sha-1 by hand by aligning and padding the buffer > accordingly and also patching in the necessary payload length. > > Apologies for my side for claiming that this is not correct sha1 > output, I was only looking at sha_transform and its implementation and > couldn't see the padding and finalization round with embedding the data > length in there and hadn't thought of it being done manually. > > Anyway, is it difficult to get the sha finalization into some common > code library? It is not very bpf specific and crypto code reviewers > won't find it there at all. Yes, sure, I'll rework it that way (early next year when I'm back if that's fine with you). Thanks, Daniel