Re: Validating Pointers

Alan Cox
2001-07-26T17:13:01Z

> Should the i386 access_ok() fail when checking a copy to/from userspace
> from/to a static in a driver module? The __copy_to|from_user work fine
> and copy_to|from_user fail, but I guess that doesn't mean access_ok()
> is the culprit. I don't know intel assembly and the platforms for
> which I do get the assembly don't do much in access_ok() so there's no
> comparing...but I'd have thought they'd be more concerned with the user
> address location than the kernel one.

You can't pass kernel address as if they were userspace. It might happen to
sometimes work on some architectures. Take a look at the set_fs() stuff