Re: [PATCH 7/7] x86/uaccess: OOPS or warn on a fault with KERNEL_DS and !pagefault_disabled()

From	Andy Lutomirski <luto@amacapital.net>
Newsgroups	linux.kernel
Subject	Re: [PATCH 7/7] x86/uaccess: OOPS or warn on a fault with KERNEL_DS and !pagefault_disabled()
Date	2016-05-29 19:00 +0200
Message-ID	<rEced-mu-11@gated-at.bofh.it> (permalink)
References	<rCtjb-Ur-9@gated-at.bofh.it> <rCtjc-Ur-21@gated-at.bofh.it> <rCJ4B-2Dy-7@gated-at.bofh.it>
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On Wed, May 25, 2016 at 8:33 AM, Borislav Petkov <bp@alien8.de> wrote:
> On Tue, May 24, 2016 at 03:48:44PM -0700, Andy Lutomirski wrote:
>> +     if (unlikely(!is_user_ds && !pagefault_disabled())) {
>> +             if (extra < TASK_SIZE_MAX) {
>> +                     /*
>> +                      * Accessing user address under KERNEL_DS.  This is a
>> +                      * bug and should be fixed, but OOPSing is not helpful
>> +                      * for exploit mitigation.
>> +                      */
>> +                     WARN_ONCE(1, "BUG: uaccess fault at 0x%lx with KERNEL_DS\n",
>
>                         WARN and BUG?
>
> Also, let's have this string and the one below differ for finding out
> where we are during debugging.

Done.

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[PATCH 7/7] x86/uaccess: OOPS or warn on a fault with KERNEL_DS and !pagefault_disabled() Andy Lutomirski <luto@kernel.org> - 2016-05-25 00:50 +0200
  Re: [PATCH 7/7] x86/uaccess: OOPS or warn on a fault with KERNEL_DS  and !pagefault_disabled() Borislav Petkov <bp@alien8.de> - 2016-05-25 17:40 +0200
    Re: [PATCH 7/7] x86/uaccess: OOPS or warn on a fault with KERNEL_DS  and !pagefault_disabled() Andy Lutomirski <luto@amacapital.net> - 2016-05-29 19:00 +0200

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