From: "Jason A. Donenfeld" Subject: Re: [kernel-hardening] Re: [PATCH v7 3/6] random: use SipHash in place of MD5 Date: Thu, 22 Dec 2016 16:41:59 +0100 Message-ID: References: <20161216030328.11602-1-Jason@zx2c4.com> <20161221230216.25341-1-Jason@zx2c4.com> <20161221230216.25341-4-Jason@zx2c4.com> <17bd0c70-d2c1-165b-f5b2-252dfca404e8@stressinduktion.org> <20161222054125.lzxhd6ctovm3wk4p@thunk.org> <1482410840.2472.2.camel@stressinduktion.org> <5c306c80-3499-8b92-21d0-c197f30ce326@stressinduktion.org> <1482420815.2673.1.camel@stressinduktion.org> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Cc: kernel-hardening@lists.openwall.com, "Theodore Ts'o" , Andy Lutomirski , Netdev , LKML , Linux Crypto Mailing List , David Laight , Eric Dumazet , Linus Torvalds , Eric Biggers , Tom Herbert , Andi Kleen , "David S. Miller" , Jean-Philippe Aumasson To: Hannes Frederic Sowa Return-path: Received: from frisell.zx2c4.com ([192.95.5.64]:47668 "EHLO frisell.zx2c4.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753067AbcLVPmF (ORCPT ); Thu, 22 Dec 2016 10:42:05 -0500 In-Reply-To: <1482420815.2673.1.camel@stressinduktion.org> Sender: linux-crypto-owner@vger.kernel.org List-ID: Hi Hannes, On Thu, Dec 22, 2016 at 4:33 PM, Hannes Frederic Sowa wrote: > IPv6 you cannot touch anymore. The hashing algorithm is part of uAPI. > You don't want to give people new IPv6 addresses with the same stable > secret (across reboots) after a kernel upgrade. Maybe they lose > connectivity then and it is extra work? Ahh, too bad. So it goes. > The bpf hash stuff can be changed during this merge window, as it is > not yet in a released kernel. Albeit I would probably have preferred > something like sha256 here, which can be easily replicated by user > space tools (minus the problem of patching out references to not > hashable data, which must be zeroed). Oh, interesting, so time is of the essence then. Do you want to handle changing the new eBPF code to something not-SHA1 before it's too late, as part of a new patchset that can fast track itself to David? And then I can preserve my large series for the next merge window. Jason