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Date: Sat, 7 Jul 2007 02:13:01 +0200 (CEST)
From: Jiri Kosina <jkosina@...e.cz>
To: Rik van Riel <riel@...hat.com>
Cc: Chuck Ebbert <cebbert@...hat.com>,
Jakub Jelinek <jakub@...hat.com>,
Andrew Morton <akpm@...ux-foundation.org>,
Jan Kratochvil <honza@...os.cz>, Ingo Molnar <mingo@...e.hu>,
linux-kernel@...r.kernel.org, Ernie Petrides <petrides@...hat.com>
Subject: Re: [PATCH][RESEND] PIE randomization
On Thu, 5 Jul 2007, Rik van Riel wrote:
> So the original patch has:
> #define BAD_ADDR(x) ((unsigned long)(x) >= TASK_SIZE)
> For some reason(?) it got changed to the clearly buggy:
> #define BAD_ADDR(x) ((unsigned long)(x) >= PAGE_MASK)
> Jiri's patch undoes that second buggy define, which is very
> different from the original that was sent in by you and Ernie.
This is a part of execshield patch, fthe pie-compiled binary executable
memory layout randomization was extracted from - see
http://people.redhat.com/~mingo/exec-shield/exec-shield-nx-2.6.19.patch
Note that load_elf_interp() in vanilla kernel differs from the
execshield's (and pie-randomization.patch) version.
The fix makes the BAD_ADDR check whether the address belongs to the
ERR_PTR range, which seems valid for all uses of BAD_ADDR in the patched
binfmt_elf.c (do_brk(), elf_map(), do_mmap() etc return valid address or
err ptr) ... am I missing something obvious here?
--
Jiri Kosina
SUSE Labs
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