Re: [PATCH] usercopy: add testcases to check zeroing on failure of usercopy

From: Kees Cook
Date: Mon Feb 13 2017 - 13:21:25 EST

On Sat, Feb 11, 2017 at 10:13 PM, Hoeun Ryu <hoeun.ryu@xxxxxxxxx> wrote:
> In the hardend usercopy, the destination buffer will be zeroed if
> copy_from_user/get_user fails. This patch adds testcases for it.
> The destination buffer is set with non-zero value before illegal
> copy_from_user/get_user is executed and the buffer is compared to
> zero after usercopy is done.
> Signed-off-by: Hoeun Ryu <hoeun.ryu@xxxxxxxxx>

This looks great!

I'll adjust the commit slightly (the zeroing always happens,
regardless of hardened usercopy) and add it to my usercopy tree.



Kees Cook
Pixel Security