[PATCH] mm: Remove HARDENED_USERCOPY_FALLBACK

[David Rientjes]

On Tue, 21 Sep 2021, 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 at sk2.org>
> Suggested-by: Kees Cook <keescook at chromium.org>

Acked-by: David Rientjes <rientjes at google.com>