Re: [PATCH] mm: Remove HARDENED_USERCOPY_FALLBACK

From: Kees Cook
Date: Tue Sep 21 2021 - 15:01:19 EST


On Tue, Sep 21, 2021 at 08:11:49AM +0200, Stephen Kitt wrote:
> This has served its purpose and is no longer used. All usercopy
> violations appear to have been handled by now, any remaining
> instances (or new bugs) will cause copies to be rejected.
>
> This isn't a direct revert of commit 2d891fbc3bb6 ("usercopy: Allow
> strict enforcement of whitelists"); since usercopy_fallback is
> effectively 0, the fallback handling is removed too.
>
> This also removes the usercopy_fallback module parameter on
> slab_common.
>
> Link: https://github.com/KSPP/linux/issues/153
> Signed-off-by: Stephen Kitt <steve@xxxxxxx>
> Suggested-by: Kees Cook <keescook@xxxxxxxxxxxx>

Thanks for doing this!

Acked-by: Kees Cook <keescook@xxxxxxxxxxxx>

--
Kees Cook