From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: David Woodhouse <dwmw2@infradead.org>
Cc: linuxppc-dev@ozlabs.org, paulus@samba.org
Subject: Re: Executing from readablee, no-exec pages
Date: Sat, 07 Jul 2007 12:33:00 +1000 [thread overview]
Message-ID: <1183775580.3388.191.camel@localhost.localdomain> (raw)
In-Reply-To: <1183732922.2747.36.camel@shinybook.infradead.org>
On Fri, 2007-07-06 at 10:42 -0400, David Woodhouse wrote:
> On Thu, 2007-07-05 at 16:55 -0500, Scott Wood wrote:
> > To maintain compatibility with these versions, we could change the test
> > in do_page_fault() to include VM_READ as well as VM_EXEC on targets that
> > don't have a separate exec-bit in hardware (are there any powerpc mmus
> > that do?).
>
> 64-bit implementations since POWER4 have separate exec permissions,
> don't they? So any userspace which tries to execute non-executable pages
> is already broken when running on a ppc64 machine; I wouldn't worry too
> much about letting it break on ppc32 too.
>
> We already use vDSO signal trampolines even on the 32-bit kernel, right?
The problem was with old glibc 32 bits which used to jump to an
instruction in the .got iirc that wasn't in an executable section
Ben.
prev parent reply other threads:[~2007-07-07 2:33 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-07-05 21:55 Executing from readablee, no-exec pages Scott Wood
2007-07-05 22:38 ` Rodrigo Rubira Branco
2007-07-06 11:18 ` Johannes Berg
2007-07-06 13:36 ` Segher Boessenkool
2007-07-06 13:43 ` Johannes Berg
2007-07-06 13:24 ` Segher Boessenkool
2007-07-06 16:49 ` Scott Wood
2007-07-07 2:33 ` Benjamin Herrenschmidt
2007-07-06 14:42 ` David Woodhouse
2007-07-07 2:33 ` Benjamin Herrenschmidt [this message]
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