Re: [Security] [PATCH] proc: avoid information leaks to non-privilegedprocesses

From: Linus Torvalds
Date: Wed May 06 2009 - 12:59:40 EST




On Wed, 6 May 2009, Matt Mackall wrote:

> On Wed, May 06, 2009 at 12:30:34PM +0200, Ingo Molnar wrote:
> > (Also, obviously "only" covering 95% of the Linux systems has its
> > use as well. Most other architectures have their own cycle counters
> > as well.)
>
> X86 might be 95% of desktop. But it's a small fraction of Linux
> systems once you count cell phones, video players, TVs, cameras, GPS
> devices, cars, routers, etc. almost none of which are x86-based. In
> fact, just Linux cell phones (with about an 8% share of a 1.2billion
> devices per year market) dwarf Linux desktops (maybe 5% of a
> 200m/y market).

Matt, are you willing to ack my suggested patch which adds history to the
mix? Did somebody test that? I have this memory of there being an
"exploit" program to show the non-randomness of the values, but I can't
recall details, and would really want to get a second opinion from
somebody who cares about PRNG's.

Linus
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