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Re: [kernel-hardening] [RFC, PATCH] x86_64: KAISER - do not map kernel in user mode

From Daniel Gruss <daniel.gruss@iaik.tugraz.at>
Newsgroups linux.kernel
Subject Re: [kernel-hardening] [RFC, PATCH] x86_64: KAISER - do not map kernel in user mode
Date 2017-05-08 16:20 +0200
Message-ID <tERG2-4Yr-7@gated-at.bofh.it> (permalink)
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On 08.05.2017 16:09, Thomas Garnier wrote:
>> Just to correct my answer here as well: Although we experimented with fixed
>> mappings for per-cpu addresses, the current patch does not incorporate this
>> yet, so it indeed still leaks. However, it is not a severe problem. The
>> mapping of the required (per-cpu) variables would be at a fixed location in
>> the user CR3, instead of the ones that are used in the kernel.
>
> Why do you think it should be at a fixed location in the user CR3? I
> see that you just mirror the entries. You also mirror
> __entry_text_start / __entry_text_end which is part of the binary so
> will leak the base address of the kernel. Maybe I am missing
> something.

As I said, the current patch does not incorporate this yet, so yes, this part currently still leaks because we did not 
implement it yet.

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[RFC, PATCH] x86_64: KAISER - do not map kernel in user mode Daniel Gruss <daniel.gruss@iaik.tugraz.at> - 2017-05-04 12:20 +0200
  Re: [RFC, PATCH] x86_64: KAISER - do not map kernel in user mode Daniel Gruss <daniel.gruss@iaik.tugraz.at> - 2017-05-04 14:30 +0200
  Re: [kernel-hardening] [RFC, PATCH] x86_64: KAISER - do not map  kernel in user mode Thomas Garnier <thgarnie@google.com> - 2017-05-04 17:30 +0200
    Re: [kernel-hardening] [RFC, PATCH] x86_64: KAISER - do not map  kernel in user mode Daniel Gruss <daniel.gruss@iaik.tugraz.at> - 2017-05-05 10:30 +0200
      Re: [kernel-hardening] [RFC, PATCH] x86_64: KAISER - do not map  kernel in user mode Thomas Garnier <thgarnie@google.com> - 2017-05-05 17:50 +0200
        Re: [kernel-hardening] [RFC, PATCH] x86_64: KAISER - do not map  kernel in user mode David Gens <david.gens@cs.tu-darmstadt.de> - 2017-05-06 06:40 +0200
          Re: [kernel-hardening] [RFC, PATCH] x86_64: KAISER - do not map  kernel in user mode Daniel Gruss <daniel.gruss@iaik.tugraz.at> - 2017-05-06 10:40 +0200
            Re: [kernel-hardening] [RFC, PATCH] x86_64: KAISER - do not map  kernel in user mode Mark Rutland <mark.rutland@arm.com> - 2017-05-08 12:30 +0200
              Re: [kernel-hardening] [RFC, PATCH] x86_64: KAISER - do not map  kernel in user mode Daniel Gruss <daniel.gruss@iaik.tugraz.at> - 2017-05-08 13:00 +0200
                Re: [kernel-hardening] [RFC, PATCH] x86_64: KAISER - do not map  kernel in user mode Mark Rutland <mark.rutland@arm.com> - 2017-05-08 15:30 +0200
                Re: [kernel-hardening] [RFC, PATCH] x86_64: KAISER - do not map  kernel in user mode Daniel Gruss <daniel.gruss@iaik.tugraz.at> - 2017-05-08 15:50 +0200
            Re: [kernel-hardening] [RFC, PATCH] x86_64: KAISER - do not map  kernel in user mode Daniel Gruss <daniel.gruss@iaik.tugraz.at> - 2017-05-08 16:00 +0200
              Re: [kernel-hardening] [RFC, PATCH] x86_64: KAISER - do not map  kernel in user mode Thomas Garnier <thgarnie@google.com> - 2017-05-08 16:20 +0200
                Re: [kernel-hardening] [RFC, PATCH] x86_64: KAISER - do not map  kernel in user mode Daniel Gruss <daniel.gruss@iaik.tugraz.at> - 2017-05-08 16:20 +0200
      Re: [kernel-hardening] [RFC, PATCH] x86_64: KAISER - do not map  kernel in user mode Daniel Gruss <daniel.gruss@iaik.tugraz.at> - 2017-05-08 15:30 +0200
  Re: [RFC, PATCH] x86_64: KAISER - do not map kernel in user mode Christoph Hellwig <hch@infradead.org> - 2017-05-04 17:50 +0200
    Re: [RFC, PATCH] x86_64: KAISER - do not map kernel in user mode Daniel Gruss <daniel.gruss@iaik.tugraz.at> - 2017-05-05 09:50 +0200
      Re: [kernel-hardening] Re: [RFC, PATCH] x86_64: KAISER - do not map  kernel in user mode Daniel Gruss <daniel.gruss@iaik.tugraz.at> - 2017-05-07 23:50 +0200
        Re: [kernel-hardening] Re: [RFC, PATCH] x86_64: KAISER - do not map  kernel in user mode Richard Weinberger <richard@nod.at> - 2017-05-08 00:10 +0200
          Re: [kernel-hardening] Re: [RFC, PATCH] x86_64: KAISER - do not map  kernel in user mode Daniel Gruss <daniel.gruss@iaik.tugraz.at> - 2017-05-08 00:20 +0200
            Re: [kernel-hardening] Re: [RFC, PATCH] x86_64: KAISER - do not mapkernel in user mode "Fogh, Anders" <anders.fogh@gdata-adan.de> - 2017-05-09 17:00 +0200
              Re: [kernel-hardening] Re: [RFC, PATCH] x86_64: KAISER - do not  mapkernel in user mode Richard Weinberger <richard@nod.at> - 2017-05-09 17:00 +0200
                Re: [kernel-hardening] Re: [RFC, PATCH] x86_64: KAISER - do not  mapkernel in user mode Rik van Riel <riel@redhat.com> - 2017-05-09 17:40 +0200
      Re: [kernel-hardening] Re: [RFC, PATCH] x86_64: KAISER - do not map  kernel in user mode Richard Weinberger <richard.weinberger@gmail.com> - 2017-05-08 00:10 +0200
  Re: [kernel-hardening] [RFC, PATCH] x86_64: KAISER - do not map  kernel in user mode Jann Horn <jannh@google.com> - 2017-05-05 18:00 +0200
    Re: [kernel-hardening] [RFC, PATCH] x86_64: KAISER - do not map  kernel in user mode Daniel Gruss <daniel.gruss@iaik.tugraz.at> - 2017-05-06 10:30 +0200
  Re: [kernel-hardening] [RFC, PATCH] x86_64: KAISER - do not map  kernel in user mode Jann Horn <jannh@google.com> - 2017-05-05 18:00 +0200

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