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From: Will Newton <>
To: "Carlos O'Donell" <>
Cc: "" <>
Subject: Re: All machines: Pointer guard testing update (Bug 15754, CVE-2013-4788).
Date: Thu, 26 Sep 2013 15:39:00 -0000	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <>

On 26 September 2013 15:52, Carlos O'Donell <> wrote:

Hi Carlos,

> The fix for CVE-2013-4788 (bug 15754) contains a regression
> test to ensure that the pointer guard is both random and
> changes between processes.
> In order to create the test it was necessary to add a new
> accessor macro POINTER_CHK_GUARD to allow the regression
> test to locate and read the pointer guard value from outside
> of the library.
> I have added a POINTER_CHK_GUARD implementation for *all*
> machines. You need not do any work at this point. However,
> for some machines I wrote the implementation without testing
> it e.g. stack guard was just before pointer guard so
> POINTER_CHK_GUARD is the same code with a different offset.
> My request is that you run the testsuite and verify that
> tst-ptrguard1 and tst-ptrguard1-static pass. If they don't
> pass please email me and we can work out what might be
> wrong with your POINTER_CHK_GUARD implementation.

I noticed that alpha does something strange in this regard.


/* There exists generic C code that assumes that PTR_MANGLE is always
   defined.  When generating code for the static libc, we don't have
   __pointer_chk_guard defined.  Nor is there any place that would
   initialize it if it were defined, so there's little point in doing
   anything more than nothing.  */
# ifndef __ASSEMBLER__
#  define PTR_MANGLE(var)
#  define PTR_DEMANGLE(var)
# endif

This looks like in the static case alpha will not benefit from the new
fix. I don't have an alpha toolchain or any particular knowledge of
alpha to verify that though.

Will Newton
Toolchain Working Group, Linaro

  reply	other threads:[~2013-09-26 15:39 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-09-26 14:52 Carlos O'Donell
2013-09-26 15:39 ` Will Newton [this message]
2013-09-26 16:26   ` Richard Henderson
2013-09-27  1:06 ` Kaz Kojima
2013-09-27  1:43   ` Carlos O'Donell
2013-09-27  2:15     ` Kaz Kojima

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