Re: [PATCH 1/9] mm: Hardened usercopy

Kees Cook [off-list ref] writes:

On Thu, Jul 7, 2016 at 4:01 AM, Arnd Bergmann [off-list ref] wrote:

quoted

On Wednesday, July 6, 2016 3:25:20 PM CEST Kees Cook wrote:

quoted

+
+     /* Allow kernel rodata region (if not marked as Reserved). */
+     if (ptr >= (const void *)__start_rodata &&
+         end <= (const void *)__end_rodata)
+             return NULL;

Should we explicitly forbid writing to rodata, or is it enough to
rely on page protection here?

Hm, interesting. That's a very small check to add. My knee-jerk is to
just leave it up to page protection. I'm on the fence. :)

There are platforms that don't have page protection, so it would be nice
if they could at least opt-in to checking for it here.

cheers

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