Re: [PATCHv4 09/10] mm/usercopy: Switch to using lm_alias

From	Mark Rutland <mark.rutland@arm.com>
Newsgroups	linux.kernel
Subject	Re: [PATCHv4 09/10] mm/usercopy: Switch to using lm_alias
Date	2016-12-07 15:00 +0100
Message-ID	<sLKVk-LK-23@gated-at.bofh.it> (permalink)
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On Tue, Dec 06, 2016 at 12:10:50PM -0800, Kees Cook wrote:
> On Tue, Dec 6, 2016 at 10:18 AM, Mark Rutland <mark.rutland@arm.com> wrote:
> > On Tue, Nov 29, 2016 at 11:39:44AM -0800, Kees Cook wrote:
> >> On Tue, Nov 29, 2016 at 10:55 AM, Laura Abbott <labbott@redhat.com> wrote:
> >> >
> >> > The usercopy checking code currently calls __va(__pa(...)) to check for
> >> > aliases on symbols. Switch to using lm_alias instead.
> >> >
> >> > Signed-off-by: Laura Abbott <labbott@redhat.com>
> >>
> >> Acked-by: Kees Cook <keescook@chromium.org>
> >>
> >> I should probably add a corresponding alias test to lkdtm...
> >>
> >> -Kees
> >
> > Something like the below?
> >
> > It uses lm_alias(), so it depends on Laura's patches. We seem to do the
> > right thing, anyhow:
> 
> Cool, this looks good. What happens on systems without an alias?

In that case, lm_alias() should be an identity function, and we'll just
hit the usual kernel address (i.e. it should be identical to
USERCOPY_KERNEL).

> Laura, feel free to add this to your series:
> 
> Acked-by: Kees Cook <keescook@chromium.org>

I'm happy with that, or I can resend this as a proper patch once the
rest is in.

Thanks,
Mark.

Thread

[PATCHv4 00/10] CONFIG_DEBUG_VIRTUAL for arm64 Laura Abbott <labbott@redhat.com> - 2016-11-29 20:00 +0100
  [PATCHv4 09/10] mm/usercopy: Switch to using lm_alias Laura Abbott <labbott@redhat.com> - 2016-11-29 20:00 +0100
    Re: [PATCHv4 09/10] mm/usercopy: Switch to using lm_alias Kees Cook <keescook@chromium.org> - 2016-11-29 20:40 +0100
      Re: [PATCHv4 09/10] mm/usercopy: Switch to using lm_alias Mark Rutland <mark.rutland@arm.com> - 2016-12-06 19:20 +0100
        Re: [PATCHv4 09/10] mm/usercopy: Switch to using lm_alias Kees Cook <keescook@chromium.org> - 2016-12-06 21:20 +0100
          Re: [PATCHv4 09/10] mm/usercopy: Switch to using lm_alias Mark Rutland <mark.rutland@arm.com> - 2016-12-07 15:00 +0100
    Re: [PATCHv4 09/10] mm/usercopy: Switch to using lm_alias Mark Rutland <mark.rutland@arm.com> - 2016-12-06 19:30 +0100
  [PATCHv4 10/10] arm64: Add support for CONFIG_DEBUG_VIRTUAL Laura Abbott <labbott@redhat.com> - 2016-11-29 20:00 +0100
    Re: [PATCHv4 10/10] arm64: Add support for CONFIG_DEBUG_VIRTUAL Mark Rutland <mark.rutland@arm.com> - 2016-12-06 20:00 +0100
  [PATCHv4 08/10] mm/kasan: Switch to using __pa_symbol and lm_alias Laura Abbott <labbott@redhat.com> - 2016-11-29 20:00 +0100
    Re: [PATCHv4 08/10] mm/kasan: Switch to using __pa_symbol and  lm_alias Laura Abbott <labbott@redhat.com> - 2016-12-01 20:20 +0100
    Re: [PATCHv4 08/10] mm/kasan: Switch to using __pa_symbol and  lm_alias Mark Rutland <mark.rutland@arm.com> - 2016-12-06 18:30 +0100
    Re: [PATCHv4 08/10] mm/kasan: Switch to using __pa_symbol and  lm_alias Mark Rutland <mark.rutland@arm.com> - 2016-12-06 18:50 +0100
    Re: [PATCHv4 08/10] mm/kasan: Switch to using __pa_symbol and  lm_alias Mark Rutland <mark.rutland@arm.com> - 2016-12-06 20:30 +0100
  [PATCHv4 06/10] xen: Switch to using __pa_symbol Laura Abbott <labbott@redhat.com> - 2016-11-29 20:00 +0100
    Re: [PATCHv4 06/10] xen: Switch to using __pa_symbol Boris Ostrovsky <boris.ostrovsky@oracle.com> - 2016-11-29 23:30 +0100
      Re: [PATCHv4 06/10] xen: Switch to using __pa_symbol Laura Abbott <labbott@redhat.com> - 2016-11-29 23:50 +0100
  [PATCH 0/3] ARM: Add support for CONFIG_DEBUG_VIRTUAL Florian Fainelli <f.fainelli@gmail.com> - 2016-12-06 21:00 +0100
    [PATCH 3/3] ARM: Add support for CONFIG_DEBUG_VIRTUAL Florian Fainelli <f.fainelli@gmail.com> - 2016-12-06 21:00 +0100
      Re: [PATCH 3/3] ARM: Add support for CONFIG_DEBUG_VIRTUAL Florian Fainelli <f.fainelli@gmail.com> - 2016-12-06 21:50 +0100
      Re: [PATCH 3/3] ARM: Add support for CONFIG_DEBUG_VIRTUAL Laura Abbott <labbott@redhat.com> - 2016-12-07 03:10 +0100
        Re: [PATCH 3/3] ARM: Add support for CONFIG_DEBUG_VIRTUAL Florian Fainelli <f.fainelli@gmail.com> - 2016-12-07 03:30 +0100
    [PATCH 2/3] ARM: Utilize __pa_symbol in lieu of __pa Florian Fainelli <f.fainelli@gmail.com> - 2016-12-06 21:00 +0100
    [PATCH 1/3] ARM: Define KERNEL_START and KERNEL_END Florian Fainelli <f.fainelli@gmail.com> - 2016-12-06 21:00 +0100
      Re: [PATCH 1/3] ARM: Define KERNEL_START and KERNEL_END Florian Fainelli <f.fainelli@gmail.com> - 2016-12-06 23:50 +0100
      RE: [PATCH 1/3] ARM: Define KERNEL_START and KERNEL_END Chris Brandt <Chris.Brandt@renesas.com> - 2016-12-06 23:50 +0100
      Re: [PATCH 1/3] ARM: Define KERNEL_START and KERNEL_END kbuild test robot <lkp@intel.com> - 2016-12-07 07:20 +0100

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