Re: [kernel-hardening] Re: [PATCH v9 1/4] syscalls: Verify address limit before returning to user-mode

Borislav Petkov
2017-05-11T11:22:34Z

On Tue, May 09, 2017 at 04:31:00PM -0700, Kees Cook wrote:
> > I don't like silent fixups. If we want to do this, we should BUG or
> > at least WARN, not just change the addr limit. But I'm also not
> > convinced it's indicative of an actual bug here.
>
> Nothing should enter that function with KERNEL_DS set, right?
>
> BUG_ON(get_fs() != USER_DS);

We're feeling triggerhappy, aren't we? A nice juicy WARN-splat along
with a fixup looks much better than killing the box, to me.

--
Regards/Gruss,
Boris.

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