Re: [PATCH v2] x86/mm: warn on W+x mappings

From	Matt Fleming <matt@codeblueprint.co.uk>
Newsgroups	linux.kernel
Subject	Re: [PATCH v2] x86/mm: warn on W+x mappings
Date	2015-10-21 22:50 +0200
Message-ID	<qm8uD-5O3-17@gated-at.bofh.it> (permalink)
References	(5 earlier) <qm19L-3rA-5@gated-at.bofh.it> <qm1CP-4fn-41@gated-at.bofh.it> <qm1CQ-4fn-51@gated-at.bofh.it> <qm2Iy-5OI-27@gated-at.bofh.it> <qm6Ct-346-7@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On Wed, 21 Oct, at 11:46:53AM, Andy Lutomirski wrote:
>
> If the UEFI stuff is mapped in its own PGD entry, we could just RO
> that entire PGD entry everywhere except the UEFI pgd (and make sure to
> clear G so that the TLB entries get zapped).

What would be the benefit of making it RO as opposed to not having it
mapped at all? The mappings only exist in the trampoline_pgd right now
for x86 which minimizes the potentially vulnerable code paths to the
EFI runtime calls and the suspend/resume code.
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Thread

Re: [PATCH v2] x86/mm: warn on W+x mappings Ingo Molnar <mingo@kernel.org> - 2015-10-21 11:50 +0200
  Re: [PATCH v2] x86/mm: warn on W+x mappings Ingo Molnar <mingo@kernel.org> - 2015-10-21 14:50 +0200
    Re: [PATCH v2] x86/mm: warn on W+x mappings Ard Biesheuvel <ard.biesheuvel@linaro.org> - 2015-10-21 15:00 +0200
      Re: [PATCH v2] x86/mm: warn on W+x mappings Borislav Petkov <bp@alien8.de> - 2015-10-21 15:30 +0200
        Re: [PATCH v2] x86/mm: warn on W+x mappings Ard Biesheuvel <ard.biesheuvel@linaro.org> - 2015-10-21 15:30 +0200
          Re: [PATCH v2] x86/mm: warn on W+x mappings Borislav Petkov <bp@alien8.de> - 2015-10-21 16:40 +0200
            Re: [PATCH v2] x86/mm: warn on W+x mappings Andy Lutomirski <luto@amacapital.net> - 2015-10-21 20:50 +0200
              Re: [PATCH v2] x86/mm: warn on W+x mappings Andy Lutomirski <luto@amacapital.net> - 2015-10-21 22:50 +0200
              Re: [PATCH v2] x86/mm: warn on W+x mappings Matt Fleming <matt@codeblueprint.co.uk> - 2015-10-21 22:50 +0200
  Re: [PATCH v2] x86/mm: warn on W+x mappings Matt Fleming <matt@codeblueprint.co.uk> - 2015-10-21 22:40 +0200

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