From mboxrd@z Thu Jan 1 00:00:00 1970 From: Johannes Schindelin Subject: Re: [PATCH] cherry: cache patch-ids to avoid repeating work Date: Thu, 10 Jul 2008 15:28:31 +0100 (BST) Message-ID: References: <7f9d599f0807082053w4603d0bbgfead9127c33b78b5@mail.gmail.com> <7vfxqjmyg2.fsf@gitster.siamese.dyndns.org> <7f9d599f0807082226oee83bedrf13d254ae12be274@mail.gmail.com> <7vprpnlglh.fsf@gitster.siamese.dyndns.org> <7f9d599f0807092034n438f0976pf44d4c9305871087@mail.gmail.com> <7f9d599f0807100709u778f0ab1y28776d7efb831b61@mail.gmail.com> Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Cc: Junio C Hamano , "git@vger.kernel.org" To: Geoffrey Irving X-From: git-owner@vger.kernel.org Thu Jul 10 16:29:34 2008 Return-path: Envelope-to: gcvg-git-2@gmane.org Received: from vger.kernel.org ([209.132.176.167]) by lo.gmane.org with esmtp (Exim 4.50) id 1KGx9J-0002WF-Re for gcvg-git-2@gmane.org; Thu, 10 Jul 2008 16:29:34 +0200 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754620AbYGJO2f (ORCPT ); Thu, 10 Jul 2008 10:28:35 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754455AbYGJO2f (ORCPT ); Thu, 10 Jul 2008 10:28:35 -0400 Received: from mail.gmx.net ([213.165.64.20]:56654 "HELO mail.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1751168AbYGJO2e (ORCPT ); Thu, 10 Jul 2008 10:28:34 -0400 Received: (qmail invoked by alias); 10 Jul 2008 14:28:33 -0000 Received: from grape.st-and.ac.uk (EHLO grape.st-and.ac.uk) [138.251.155.28] by mail.gmx.net (mp010) with SMTP; 10 Jul 2008 16:28:33 +0200 X-Authenticated: #1490710 X-Provags-ID: V01U2FsdGVkX19N/kwCZNZNEv0q5uzjcL2zP7P8c7yf4/a4HwYzWp 4y6BzGHFw92SaB X-X-Sender: gene099@racer In-Reply-To: <7f9d599f0807100709u778f0ab1y28776d7efb831b61@mail.gmail.com> User-Agent: Alpine 1.00 (DEB 882 2007-12-20) X-Y-GMX-Trusted: 0 X-FuHaFi: 0.64 Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org Archived-At: Hi, On Thu, 10 Jul 2008, Geoffrey Irving wrote: > On Wed, Jul 9, 2008 at 8:34 PM, Geoffrey Irving wrote: > > > Note: there are at least two "holes" in this code. First, it is > > impossible to verify the validity of the entries (this is impossible > > to fix). Second, it is possible to write a malicious patch-id-cache > > file that causes git-cherry to go into an infinite loop. Fixing the > > loop requires either traversing every entry on load (bad) or adding a > > second loop termination condition to find_helper. Since looping > > forever is better than returning incorrect results, I figured fixing > > the weaker hole would just result in a false sense of security. > > Oops: avoiding the infinite loop only requires reading expected O(1) > entries on load, so I can fix that if you like. It would only be all of > them if it actually did detect the infinite loop. I have to admit that you lost me there. AFAIR the patch-id cache is a simple commit->patch_id store, right? Then there should be no way to get an infinite loop. Besides, this is a purely local cache, no? Never to be transmitted... So not much chance of a malicious attack, except if you allow write access to your local repository, in which case you are endangered no matter what. Ciao, Dscho