Re: [PATCH] libnvdimm/pmem: Bypass CONFIG_HARDENED_USERCOPY overhead

Kees Cook
2019-05-17T16:40:35Z

On Fri, May 17, 2019 at 04:14:03PM +0000, David Laight wrote:
> From: Kees Cook
> > Sent: 17 May 2019 16:54
> ...
> > > I've changed some of our code to use __get_user() to avoid
> > > these stupid overheads.
> >
> > __get_user() skips even access_ok() checking too, so that doesn't seem
> > like a good idea. Did you run access_ok() checks separately? (This
> > generally isn't recommended.)
>
> Of course, I'm not THAT stupid :-)

Right, yes, I know. :) I just wanted to double-check since accidents
can happen. The number of underscores on these function is not really
a great way to indicate what they're doing. ;)

--
Kees Cook