Re: [PATCH] x86/uaccess: Use pointer masking to limit uaccess speculation

[Josh Poimboeuf]

On Tue, Sep 01, 2020 at 08:32:20AM +0000, David Laight wrote:
> > Yes, it would make sense to put the masking in access_ok() somehow.  But
> > to do it properly, I think we'd first need to make access_ok() generic.
> > Maybe that's do-able, but it would be a much bigger patch set.
> > 
> > First I'd prefer to just fix x86, like my patch does.  Then we could do
> > an access_ok() rework.
> 
> If you do a modified access_ok() you get to (slowly) collect all
> the important paths.
> No point replicating the same test.
> 
> A lot of the access_ok() can be deleted - maybe remove some __
> from the following functions.
> Or change to the variants that enable user-space accesses.

Well, yes, but that's a much bigger job which can be done later.

-- 
Josh