From: Ingo Molnar <mingo@elte.hu>
To: Matt Mackall <mpm@selenic.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
"Eric W. Biederman" <ebiederm@xmission.com>,
Arjan van de Ven <arjan@infradead.org>, Jake Edge <jake@lwn.net>,
security@kernel.org,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
James Morris <jmorris@namei.org>,
linux-security-module@vger.kernel.org,
Eric Paris <eparis@redhat.com>,
Alan Cox <alan@lxorguk.ukuu.org.uk>,
Roland McGrath <roland@redhat.com>,
mingo@redhat.com, Andrew Morton <akpm@linux-foundation.org>,
Greg KH <greg@kroah.com>, Dave Jones <davej@redhat.com>
Subject: Re: [Security] [PATCH] proc: avoid information leaks to non-privileged processes
Date: Tue, 5 May 2009 08:31:56 +0200 [thread overview]
Message-ID: <20090505063156.GA24504@elte.hu> (raw)
In-Reply-To: <20090505055011.GE31071@waste.org>
* Matt Mackall <mpm@selenic.com> wrote:
> As to what's the appropriate sort of RNG for ASLR to use, finding
> a balance between too strong and too weak is tricky. [...]
In exec-shield i mixed 'easily accessible and fast' semi-random
state to the get_random_int() result: xor-ed the cycle counter, the
pid and a kernel address to it. That strengthened the result in a
pretty practical way (without strengthening the theoretical
randomless - each of those items are considered guessable) and does
so without weakening the entropy of the random pool.
As usual, it got objected to and removed during upstream review so
the upstream code stands on a single foot only - which is an
obviously bad idea.
The thing is, it's very hard to argue for (and prove) security
related complexity on an objective basis. ASLR was met with quite
some upstream hostility, so it did not really get merged upstream,
it barely managed to limp upstream.
Ingo
next prev parent reply other threads:[~2009-05-05 6:35 UTC|newest]
Thread overview: 60+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-05-04 18:51 [PATCH] proc: avoid information leaks to non-privileged processes Jake Edge
2009-05-04 19:00 ` [Security] " Linus Torvalds
2009-05-04 19:51 ` Arjan van de Ven
2009-05-04 20:20 ` Eric W. Biederman
2009-05-04 22:24 ` Linus Torvalds
2009-05-04 23:26 ` Arjan van de Ven
2009-05-04 23:54 ` Linus Torvalds
2009-05-05 7:51 ` Eric W. Biederman
2009-05-05 15:17 ` Linus Torvalds
2009-05-05 15:35 ` Linus Torvalds
2009-05-05 16:18 ` Matt Mackall
2009-05-05 16:10 ` Matt Mackall
2009-05-05 5:50 ` Matt Mackall
2009-05-05 6:31 ` Ingo Molnar [this message]
2009-05-05 8:14 ` Eric W. Biederman
2009-05-05 19:52 ` Ingo Molnar
2009-05-05 20:22 ` Matt Mackall
2009-05-05 21:20 ` Eric W. Biederman
2009-05-06 10:33 ` Ingo Molnar
2009-05-06 10:30 ` Ingo Molnar
2009-05-06 16:25 ` Matt Mackall
2009-05-06 16:48 ` Linus Torvalds
2009-05-06 17:57 ` Matt Mackall
2009-05-07 0:50 ` Matt Mackall
2009-05-07 15:02 ` Ingo Molnar
2009-05-07 18:14 ` Matt Mackall
2009-05-07 18:21 ` Ingo Molnar
2009-05-07 18:41 ` Ingo Molnar
2009-05-07 19:24 ` Matt Mackall
2009-05-07 15:16 ` Florian Weimer
2009-05-07 16:55 ` Matt Mackall
2009-05-07 17:53 ` Linus Torvalds
2009-05-07 18:42 ` Matt Mackall
2009-05-06 20:09 ` [patch] random: make get_random_int() more random Ingo Molnar
2009-05-06 20:41 ` Matt Mackall
2009-05-06 20:51 ` Ingo Molnar
2009-05-06 21:10 ` Matt Mackall
2009-05-06 21:24 ` Ingo Molnar
2009-05-14 22:47 ` Jake Edge
2009-05-14 22:55 ` [Security] " Linus Torvalds
2009-05-15 13:47 ` Ingo Molnar
2009-05-15 15:10 ` Jake Edge
2009-05-16 10:00 ` Willy Tarreau
2009-05-16 10:39 ` Ingo Molnar
2009-05-16 12:02 ` Eric W. Biederman
2009-05-16 14:00 ` Michael S. Zick
2009-05-16 14:28 ` Michael S. Zick
2009-05-16 14:57 ` Arjan van de Ven
2009-05-16 15:09 ` Michael S. Zick
2009-05-16 14:32 ` Matt Mackall
2009-05-16 13:58 ` Willy Tarreau
2009-05-16 15:23 ` Linus Torvalds
2009-05-16 15:47 ` Willy Tarreau
2009-05-16 15:54 ` Oliver Neukum
2009-05-16 16:05 ` Linus Torvalds
2009-05-16 16:17 ` Linus Torvalds
2009-05-15 1:16 ` Américo Wang
2009-05-06 20:25 ` [Security] [PATCH] proc: avoid information leaks to non-privileged processes Ingo Molnar
2009-05-06 20:52 ` Matt Mackall
2009-05-05 8:58 ` Andi Kleen
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