Re: exploiting overflowed kmalloc() memory?
On Fri, 18 Jun 2004 13:53:47 -0400
infamous41md@xxxxxxxxxx wrote:
>
> has anyone done any research on exploiting overflows with memory returned by
> kmalloc()? after briefly looking at source, i see that internally it relies
> on the kmem_cache_alloc() functions. i didn't see any sort of coalescing as
> with dlmalloc, so maybe it's not even possible? anyone have any links/info
> about this?
>
well i did a bit of research this weekend, here are my results:
http://www.1nfamus.netfirms.com/Kmalloc_Internals.html . in short is nearly
impossible to exploit in any reliable fashion. the control data is stored at
lower addresses than the memory returned by kmalloc(), so you would need an
underflow. and even in that situation, you need some serious luck and need to
perform some magic to restore the state u overwrite.
--
-sean