Re: [PATCH RFC] uaccess: user_access_begin_after_access_ok()

Michael S. Tsirkin
2020-06-04T16:47:43Z

On Thu, Jun 04, 2020 at 04:03:35PM +0100, Al Viro wrote:
> On Thu, Jun 04, 2020 at 06:10:23AM -0400, Michael S. Tsirkin wrote:
>
> > stac()
> > for (i = 0; i < 64; ++i) {
> > get_user(flags, desc[i].flags)
> unsafe_get_user(), please.
> > smp_rmb()
> > if (!(flags & VALID))
> > break;
> > copy_from_user(&adesc[i], desc + i, sizeof adesc[i]);
> ... and that would raw_copy_from_user() (or unsafe_copy_from_user(),
> for wrapper that would take a label to bugger off to)
> > }
> > clac()

Absolutely, that's all just pseudo-code.

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