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Re: [PATCH] BZ #15754: CVE-2013-4788: PTR_MANGLE does not initialize to a random value for the pointer guard when compiling static executables
- From: Andreas Schwab <schwab at suse dot de>
- To: "Carlos O'Donell" <carlos at redhat dot com>
- Cc: "Joseph S. Myers" <joseph at codesourcery dot com>, GNU C Library <libc-alpha at sourceware dot org>, Ismael Ripoll <iripoll at disca dot upv dot es>, Hector Marco <hecmargi at upv dot es>, Siddhesh Poyarekar <siddhesh at redhat dot com>, Andreas Jaeger <aj at suse dot com>
- Date: Wed, 07 Aug 2013 17:22:56 +0200
- Subject: Re: [PATCH] BZ #15754: CVE-2013-4788: PTR_MANGLE does not initialize to a random value for the pointer guard when compiling static executables
- References: <51E8EDF2 dot 40204 at redhat dot com> <Pine dot LNX dot 4 dot 64 dot 1307191644090 dot 9428 at digraph dot polyomino dot org dot uk> <51EC3044 dot 4080509 at redhat dot com>
"Carlos O'Donell" <carlos@redhat.com> writes:
> - Fix sysdeps/generic/stackguard-macros.h
>
> * sysdeps/generic/stackguard-macros.h: Define __pointer_chk_guard
> and POINTER_CHK_GUARD.
>
> diff --git a/sysdeps/generic/stackguard-macros.h b/sysdeps/generic/stackguard-macros.h
> index ababf65..77408c6 100644
> --- a/sysdeps/generic/stackguard-macros.h
> +++ b/sysdeps/generic/stackguard-macros.h
> @@ -2,3 +2,6 @@
>
> extern uintptr_t __stack_chk_guard;
> #define STACK_CHK_GUARD __stack_chk_guard
> +
> +extern uintptr_t __pointer_chk_guard;
> +#define POINTER_CHK_GUARD __pointer_chk_guard
That won't work, __pointer_chk_guard is only available in ld.so, it is
called __pointer_chk_guard_local in libc.a.
Andreas.
--
Andreas Schwab, SUSE Labs, schwab@suse.de
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