Re: [kernel-hardening] Re: [PATCH 9/9] mm: SLUB hardened usercopy support

On Fri, 8 Jul 2016, Kees Cook wrote:

Is check_valid_pointer() making sure the pointer is within the usable
size? It seemed like it was checking that it was within the slub
object (checks against s->size, wants it above base after moving
pointer to include redzone, etc).

check_valid_pointer verifies that a pointer is pointing to the start of an
object. It is used to verify the internal points that SLUB used and
should not be modified to do anything different.