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From: Bill Davidsen <davidsen@tmr.com>
To: Adrian Bunk <bunk@kernel.org>
Cc: Marc Haber <mh+linux-kernel@zugschlus.de>, linux-kernel@vger.kernel.org
Subject: Re: Why does reading from /dev/urandom deplete entropy so much?
Date: Tue, 11 Dec 2007 10:42:49 -0500	[thread overview]
Message-ID: <475EAFF9.9020405@tmr.com> (raw)
In-Reply-To: <20071208220345.GE20441@stusta.de>

Adrian Bunk wrote:
> On Thu, Dec 06, 2007 at 02:32:05PM -0500, Bill Davidsen wrote:
>   
>> ...
>> Sounds like a local DoS attack point to me...
>>     
>
> As long as /dev/random is readable for all users there's no reason to 
> use /dev/urandom for a local DoS...
>   

The original point was that urandom draws entropy from random, and that 
it is an an inobvious and unintentional drain on the entropy pool. At 
least that's how I read it. I certainly have programs which draw on 
urandom simply because it's a convenient source of meaningless data. I 
have several fewer since this discussion started, though, now that I 
have looked at the easy alternatives.

-- 
Bill Davidsen <davidsen@tmr.com>
  "Woe unto the statesman who makes war without a reason that will still
  be valid when the war is over..." Otto von Bismark 



  parent reply	other threads:[~2007-12-11 15:25 UTC|newest]

Thread overview: 77+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-12-04 11:41 Why does reading from /dev/urandom deplete entropy so much? Marc Haber
2007-12-04 14:16 ` Eric Dumazet
2007-12-04 16:18 ` Adrian Bunk
2007-12-04 16:47   ` Alan Cox
2007-12-04 18:17     ` Eric Dumazet
2007-12-05 21:26       ` Matt Mackall
2007-12-06  7:02         ` Eric Dumazet
2007-12-06 16:09           ` Matt Mackall
2007-12-09 12:42         ` Marc Haber
2007-12-09 16:16           ` Matt Mackall
2007-12-10 23:06             ` Marc Haber
2007-12-10 23:35               ` Matt Mackall
2007-12-11  1:34                 ` Theodore Tso
2007-12-11 19:46                   ` Phillip Susi
2007-12-11 20:02                     ` Ray Lee
2007-12-12  5:34                     ` David Schwartz
2007-12-04 16:54   ` Ray Lee
2007-12-04 16:55     ` Alan Cox
2007-12-04 18:02       ` Matt Mackall
2007-12-04 19:50         ` Theodore Tso
2007-12-04 20:36           ` Matt Mackall
2007-12-04 20:40           ` Alan Cox
2007-12-04 20:48             ` Mike McGrath
2007-12-04 21:54               ` Matt Mackall
2007-12-04 22:03               ` Theodore Tso
2007-12-04 22:12                 ` Mike McGrath
2007-12-04 22:28                   ` Matt Mackall
2007-12-04 21:08             ` Matt Mackall
2007-12-04 21:18               ` Mike McGrath
2007-12-04 22:15                 ` Matt Mackall
2007-12-04 22:23                   ` Mike McGrath
2007-12-04 22:33                     ` Matt Mackall
2007-12-05 14:26                       ` Mike McGrath
2007-12-05 14:49                         ` Theodore Tso
2007-12-08  7:38                           ` Jon Masters
2007-12-08 17:32                             ` Theodore Tso
2007-12-08 17:33                               ` Mike McGrath
2007-12-08 17:49                                 ` Theodore Tso
2007-12-08 17:54                                   ` Jon Masters
2007-12-08 18:15                                   ` Matt Mackall
2007-12-08 18:24                                     ` Theodore Tso
2007-12-08 19:36                                     ` entropy gathering (was Re: Why does reading from /dev/urandom deplete entropy so much?) Jeff Garzik
2007-12-08 19:53                                       ` Matt Mackall
2007-12-08 20:04                                         ` Jeff Garzik
2007-12-08 20:19                                           ` Matt Mackall
2007-12-08 21:07                                             ` Willy Tarreau
2007-12-08 20:31                                           ` Theodore Tso
2007-12-08 20:47                                             ` Jeff Garzik
2007-12-08 20:42                                       ` Willy Tarreau
2007-12-08 23:47                                         ` Theodore Tso
2007-12-09  1:07                                           ` Jon Masters
2007-12-08 18:31                                   ` Why does reading from /dev/urandom deplete entropy so much? Jeff Garzik
2007-12-08 20:26                                     ` David Schwartz
2007-12-08 17:43                               ` Matt Mackall
2007-12-08 17:47                                 ` Jon Masters
2007-12-08 18:05                                 ` Theodore Tso
2007-12-08 17:45                               ` Jon Masters
2007-12-10 16:37                           ` Pavel Machek
2007-12-04 18:01     ` Matt Mackall
2007-12-06 20:08       ` Bill Davidsen
2007-12-05 12:23     ` Marc Haber
2007-12-05 12:29   ` Marc Haber
2007-12-05 13:33     ` Theodore Tso
2007-12-05 15:10       ` Marc Haber
2007-12-06 19:32   ` Bill Davidsen
2007-12-08 22:03     ` Adrian Bunk
2007-12-08 22:10       ` Ismail Dönmez
2007-12-08 23:46         ` Theodore Tso
2007-12-09  5:21           ` Willy Tarreau
2007-12-09  6:52             ` Jon Masters
2007-12-09  6:21           ` Ismail Dönmez
2007-12-09 12:31             ` Theodore Tso
2007-12-09 14:06               ` Ismail Dönmez
2007-12-11 15:42       ` Bill Davidsen [this message]
2007-12-20 22:27         ` Marc Haber
2007-12-26 18:27           ` Phillip Susi
2007-12-04 18:49 ` Russ Dill

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