NULL pointers in kernel space
Posted Jul 17, 2009 17:13 UTC (Fri) by corbet
In reply to: Linux 2.6.30 exploit posted
Parent article: Linux 2.6.30 exploit posted
I think the only way that could be done would be to just remove the user-space page tables entirely on entry into the kernel. There's a precedent for that - the 4G/4G patches did it years ago. But it's a very expensive thing to do, to the point that people wouldn't really stand for it. Far better to just configure the kernel not to allow mappings at zero.
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