Re: [PATCH 2/2] x86: fix __user annotations

[Ben Dooks]

On 2019-03-29 13:39, Borislav Petkov wrote:
> On Thu, Mar 28, 2019 at 10:23:21PM +0100, Jann Horn wrote:
> > Fix __user annotations in various places across the x86 tree:
> >
> >  - cast to wrong pointer type in __user_atomic_cmpxchg_inatomic()
> >  - generic_load_microcode() deals with a pointer that can be either a
> >    kernel pointer or a user pointer; change the code to pass it around 
> > as
> >    a __user pointer, and add explicit casts to convert between __user 
> > and
> >    __kernel
> >  - save_xstate_epilog() has missing __user in explicit casts
> >  - setup_sigcontext() and x32_setup_rt_frame() rely on the cast 
> > performed
> >    by put_user_ex() on its first argument, but sparse requires __force 
> > for
> >    casting __user pointers to unsigned long
> >  - xen_hvm_config() has missing __user
> >
> > This patch removes all sparse warnings about the asn:1 address space
> > (__user) in arch/x86/ for my kernel config.
> >
> > Signed-off-by: Jann Horn <jannh@xxxxxxxxxx>
> > ---
> > This patch requires the previous one, "[PATCH 1/2] kernel.h: use
> > parentheses around argument in u64_to_user_ptr()", otherwise
> > xen_hvm_config() breaks. Can we take both together through the x86 
> > tree,
> > or does the first one have to go through akpm's tree?
>
> I don't see why not, unless akpm has objections.
>
> However,
>
> >  arch/x86/include/asm/uaccess.h        |  3 +--
> >  arch/x86/include/asm/uaccess_64.h     |  2 +-
>
> This chunk is being discussed here already:
>
> https://lkml.kernel.org/r/20190228185027.2480-1-ben.dooks@xxxxxxxxxxxxxxx
>
> and I'd like to take Ben's v2 when Ben adds Linus' explanation.

I'll sort that out in a bit, thanks for reviewing.