Date: Tue, 4 Dec 2007 16:33:46 -0600
From: Matt Mackall <mpm@selenic.com>
To: Mike McGrath <mmcgrath@redhat.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>, Theodore Tso <tytso@mit.edu>,
       Ray Lee <ray@madrabbit.org>, Adrian Bunk <bunk@kernel.org>,
       Marc Haber <mh+linux-kernel@zugschlus.de>, linux-kernel@vger.kernel.org
Subject: Re: Why does reading from /dev/urandom deplete entropy so much?
Message-ID: <20071204223345.GJ19691@waste.org>
References: <20071204161811.GB15974@stusta.de> <2c0942db0712040854u17a830b9see663742b2716457@mail.gmail.com> <20071204165502.0a8f695e@the-village.bc.nu> <20071204180237.GU19691@waste.org> <20071204195021.GB7259@thunk.org> <20071204204036.484f11ac@the-village.bc.nu> <20071204210827.GE19691@waste.org> <4755C423.60907@redhat.com> <20071204221525.GG19691@waste.org> <4755D350.1080801@redhat.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <4755D350.1080801@redhat.com>
User-Agent: Mutt/1.5.13 (2006-08-11)
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1517
Lines: 38

On Tue, Dec 04, 2007 at 04:23:12PM -0600, Mike McGrath wrote:
> Matt Mackall wrote:
> >On Tue, Dec 04, 2007 at 03:18:27PM -0600, Mike McGrath wrote:
> >  
> >>Matt Mackall wrote:
> >>    
> >>>which would have been in v2.6.22-rc4 through the normal CVE process.
> >>>The only other bits in there are wall time and utsname, so systems
> >>>with no CMOS clock would behave repeatably. Can we find out what
> >>>kernels are affected?
> >>>
> >>> 
> >>>      
> >>We can but it will likely take a few weeks to get a good sampling. UUID 
> >>is unique in the db so when someone checks in with the same UUID, the 
> >>old one gets overwritten.
> >>    
> >
> >We can probably assume that for whatever reason the two things with
> >duplicate UUID had the same seed. If not, we've got -much- bigger
> >problems.
> >  
> 
> Ok, I think I see whats going on here. I have some further investigation 
> to do but it seems that the way our Live CD installer works is causing 
> these issues. I'm going to try to grab some live CD's and hardware to 
> confirm but at this point it seems thats whats going on.

Alright, keep me posted. We probably need a scheme to make the initial
seed more robust regardless of what you find out.

-- 
Mathematics is the supreme nostalgia of our time.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/