From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx2.fusionio.com ([66.114.96.31]:57243 "EHLO mx2.fusionio.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756091Ab2LNO3f (ORCPT ); Fri, 14 Dec 2012 09:29:35 -0500 Date: Fri, 14 Dec 2012 09:29:32 -0500 From: Chris Mason To: Chris Mason CC: David Sterba , Pascal Junod , linux-btrfs Subject: Re: [btrfs] is vulnerable to a hash-DoS attack Message-ID: <20121214142932.GB19606@shiny> References: <50C9D085.3020305@junod.info> <20121213205208.GA27308@shiny> <20121213213430.GB22426@twin.jikos.cz> <20121213220727.GC27308@shiny> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" In-Reply-To: <20121213220727.GC27308@shiny> Sender: linux-btrfs-owner@vger.kernel.org List-ID: On Thu, Dec 13, 2012 at 03:07:27PM -0700, Chris Mason wrote: > On Thu, Dec 13, 2012 at 02:34:30PM -0700, David Sterba wrote: > > On Thu, Dec 13, 2012 at 03:52:08PM -0500, Chris Mason wrote: > > > Thanks for taking the time to write this up. As far as I can tell, the > > > looping was actually fixed in an older kernel and I just misread our > > > version string in your original email. > > > > Yeah, the blogpost says 3.3.7. I did a quick test with 3.7 and was not > > able to reproduce it. > > I tried with 3.3 and every step between 3.3 and 3.7. I'm not able to > reproduce the problem, and I did run with Hack=True in the script > (thanks for the flag btw, I really like that). > > So, that leaves us with a few possibilities: > > 1) mount -o seclabel > 2) The small size of the device > 3) loopback > > I ran with a 1GB FS here on 3.3 and wasn't able to trigger things. But > Pascal, could you please help narrow the problem down? Ok, I think what was happening on Pascal's machine is that we are returning -EOVERFLOW and sometimes aborting the transaction (which turns the FS readonly). I have that fixed here. Rename I'm reodering the rename code a little bit to also handle the case where there are collisions on rename. -chris