valgrind partially broken by current hardy-proposed kernel?

[Kees Cook]

Hi Colin,

On Mon, Jun 02, 2008 at 01:09:44PM +0100, Colin Watson wrote:
> I'm getting this rather strange effect with the -17.31 kernel:
> 
>   <cjwatson at sarantium ~/src/debian/openssh/trunk/openssh>$ valgrind build-deb/ssh-add -l
>   valgrind: mmap(0x0, 90112) failed in UME with error 13 (Permission denied).
> 
> [snip]
> My best guess is that this is due to this commit:
> 
> commit 893f802872c3e3c6e4bb40c3be4845784b81b934
> Author: Kees Cook <kees.cook at canonical.com>
> Date:   Tue Apr 8 13:51:05 2008 -0700
> 
>     UBUNTU: AppArmor: implement mmap_min_addr check as done in mainline.
>     OriginalAuthor: John Johansen <jjohansen at suse.de>
> 
>     Implement the missing mmap_min_addr check in AppArmor mmap wrapper.
> 
>     Signed-off-by: John Johansen <jjohansen at suse.de>
>     Signed-off-by: Kees Cook <kees.cook at canonical.com>
> 
> Any idea what's going on here? Is this a valgrind bug or an apparmor
> bug? Note that it doesn't seem to happen with things like 'valgrind ls'.

That change was made for the release kernel, so you should see it with
-16 too.  Blocking NULL is a feature.  :)

Why is ssh-add trying to allocate memory at 0x0?

-Kees

-- 
Kees Cook
Ubuntu Security Team