valgrind partially broken by current hardy-proposed kernel?

Kees Cook kees at canonical.com
Wed Jun 4 16:12:20 BST 2008


Hi,

On Wed, Jun 04, 2008 at 01:30:55PM +0100, Matthew Garrett wrote:
> On Mon, Jun 02, 2008 at 03:07:10PM -0700, Kees Cook wrote:
> 
> > True, but the mmap_min_addr setting only affects MAP_FIXED, in which
> > you really want address 0.  (And yes, that's valid, but not common.)
> > The common use-case of use NULL to just get an arbitrary mapping is done
> > without MAP_FIXED.
> 
> vbetool needs to map address 0 with MAP_FIXED in order to get the IDT.

Yes, but it (and usplash) run as root, which is exempt from this check.
(Wine and dosemu use this area as well, and for those use cases, people
have been advised to change the limit back to 0.  For the default use-cases,
there is no problem.)

-Kees

-- 
Kees Cook
Ubuntu Security Team



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