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: Thu, 7 May 2009 20:21:04 +0200 [thread overview]
Message-ID: <20090507182104.GA30659@elte.hu> (raw)
In-Reply-To: <20090507181434.GL31071@waste.org>
* Matt Mackall <mpm@selenic.com> wrote:
> > aldebaran:~/l> ./lat_proc fork
> > Process fork+exit: 61.7865 microseconds
>
> Uh, what? There's no exec() involved in fork+exit, so hopefully
> ASLR doesn't decide to make an appearance.
We use it to seed the per task stackprotector secret. Look for
get_random_int() in kernel/fork.c.
(
Now, if get_random_int() slows down we could certainly water that
down and have a system-wide secret and some easy and fast
long-cycle permutation code to make it not so easy to figure out
the core secret from a kernel crash signature.
[ Alas, that might be worth doing in any case - to not have
get_random_int() in the clone() / pthread_create() fastpath. ]
We really need a design decision there - if get_random_int() is
supposed to be a mathematically safe hash, ignoring the physics of
the world, then we need a separate get_random_int_fast() API or
so. All current users of get_random_int() will evaporate as well.
)
Ingo
next prev parent reply other threads:[~2009-05-07 18:22 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
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 [this message]
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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