Subject: Re: [PATCH] getrusage sucks
From: Lee Revell <rlrevell@joe-job.com>
To: David Wagner <daw-usenet@taverner.CS.Berkeley.EDU>
Cc: linux-kernel@vger.kernel.org
In-Reply-To: <dl18ro$l0f$1@taverner.CS.Berkeley.EDU>
References: <200511102334.10926.cloud.of.andor@gmail.com>
	 <dl18ro$l0f$1@taverner.CS.Berkeley.EDU>
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Date: Fri, 11 Nov 2005 14:09:58 -0500
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On Fri, 2005-11-11 at 05:06 +0000, David Wagner wrote:
> Claudio Scordino  wrote:
> >Does exist any _real_ reason why getrusage can't be invoked by a task to know 
> >statistics of another task ?
> 
> Probably only super-user should be permitted to read the usage information
> about other processes.  Allowing anyone to read anyone else's rusage would
> open up a bunch of side channels that sound pretty dangerous.  For instance,
> user #1 might be able to mount a timing attack against crypto code being
> executed by user #2, and that doesn't sound good.

Why restrict it to root?  Why not just prevent users from reading other
users rusage.  How could it be a security hole for joeuser's process be
able to read the rusage of joeuser's other processes?

Lee

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