From: Matt Mackall <mpm@selenic.com>
To: "Bob O'Neill" <rmoneill@gmail.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: reading the same entropy twice
Date: Tue, 22 Feb 2005 22:39:41 -0800 [thread overview]
Message-ID: <20050223063940.GD3163@waste.org> (raw)
In-Reply-To: <4b325ef050222135529a2584a@mail.gmail.com>
On Tue, Feb 22, 2005 at 04:55:39PM -0500, Bob O'Neill wrote:
> Hello.
>
> I have noticed that it is possible on an SMP box for two processes to
> simultaneously read the same entropy out of /dev/urandom. This
> doesn't seem right to me. I was using the entropy value to generate a
> random number to use as a session ID, so occasionally there would be a
> collision on session IDs, causing a login failure as session IDs are
> required to be unique. This issue does not appear to be related to
> entropy depletion.
>
> Could you provide me with some insight into why this is the case, if
> it is intentional? It seems like it could be addressed with a
> spinlock.
This should be fixed in current kernels.
--
Mathematics is the supreme nostalgia of our time.
prev parent reply other threads:[~2005-02-23 6:39 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-02-22 21:55 reading the same entropy twice Bob O'Neill
2005-02-22 22:08 ` Lee Revell
2005-02-23 6:39 ` Matt Mackall [this message]
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