From: David Woodhouse <dwmw2@infradead.org>
To: Hugh Dickins <hugh@veritas.com>
Cc: Andrew Morton <akpm@osdl.org>, Linus Torvalds <torvalds@osdl.org>,
Marcus Meissner <meissner@suse.de>, Andi Kleen <ak@suse.de>,
Ingo Molnar <mingo@elte.hu>, Dave Jones <davej@codemonkey.org.uk>,
Arjan van de Ven <arjan@linux.intel.com>,
linux-kernel@vger.kernel.org
Subject: Re: revert PIE randomization?
Date: Sun, 07 Jan 2007 06:42:12 +0800 [thread overview]
Message-ID: <1168123332.24110.41.camel@shinybook.infradead.org> (raw)
In-Reply-To: <Pine.LNX.4.64.0701062005001.22171@blonde.wat.veritas.com>
On Sat, 2007-01-06 at 20:11 +0000, Hugh Dickins wrote:
> And I notice that Andi added a personality & ADDR_NO_RANDOMIZE check
> into randomize_stack_top: I cannot see why that's necessary there,
> but if it is, then should the ET_DYN case add it too?)
While I think of it... it seems that ADDR_NO_RANDOMIZE isn't "inherited"
across exec of 32-bit binaries on x86_64 or ppc64. The personality flags
get wiped out when we detect a 32-bit ELF executable and set the
personality to PER_LINUX32.
This causes suboptimal behaviour from userspace code which checks
whether it can set ADDR_NO_RANDOMIZE with a sys_personality() call, and
if so re-execs itself. Run on x86_64 or ppc64, these go into an endless
loop because it always gets cleared in the exec.
I've seen such code in two places recently (Macaulay2 and sbcl, iirc).
--
dwmw2
next prev parent reply other threads:[~2007-01-06 22:42 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-01-06 20:11 Hugh Dickins
2007-01-06 21:04 ` Linus Torvalds
2007-01-06 21:08 ` Marcus Meissner
2007-01-06 21:45 ` Ingo Molnar
2007-01-06 21:54 ` Marcus Meissner
2007-01-06 22:42 ` David Woodhouse [this message]
2007-03-21 18:17 ` Kees Cook
2007-03-21 20:01 ` Hugh Dickins
2007-03-26 20:17 ` Kees Cook
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