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SubjectRe: [PATCH] Make LIST_POISON less deadly
On Sun 2008-05-18 18:38:14, Avi Kivity wrote:
> The list macros use LIST_POISON1 and LIST_POISON2 as undereferencable
> pointers in order to trap erronous use of freed list_heads. Unfortunately
> userspace can arrange for those pointers to actually be dereferencable,
> potentially turning an oops to an expolit.
>
> To avoid this allow architectures (currently x86_64 only) to override
> the default values for these pointers with truly-undereferncable values.
> This is easy on x86_64 as the virtual address space is smaller than
> the range spanned by pointer values.

"Security hole unless arch maintainer does _foo_" sounds
scary. Especially when i386 is hard to fix...

(And very nice catch, btw).
Pavel

--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html


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