Re: [PATCH v8 3/8] arm64: untag user addresses in access_ok and __uaccess_mask_ptr

[Catalin Marinas]

On Thu, Nov 08, 2018 at 03:36:10PM +0100, Andrey Konovalov wrote:
> copy_from_user (and a few other similar functions) are used to copy data
> from user memory into the kernel memory or vice versa. Since a user can
> provided a tagged pointer to one of the syscalls that use copy_from_user,
> we need to correctly handle such pointers.
> 
> Do this by untagging user pointers in access_ok and in __uaccess_mask_ptr,
> before performing access validity checks.
> 
> Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx>

Reviewed-by: Catalin Marinas <catalin.marinas@xxxxxxx>