Re: [PATCH][RESEND] PIE randomization

[Jiri Kosina]

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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