Re: [PATCH 2/5] x86-64: Give vvars their own page

From: Andrew Lutomirski
Date: Sun May 29 2011 - 21:38:14 EST


On Sun, May 29, 2011 at 4:34 PM, Borislav Petkov <bp@xxxxxxxxx> wrote:
> On Fri, May 27, 2011 at 01:38:39PM -0400, Andy Lutomirski wrote:
>> Move vvars out of the vsyscall page into their own page and mark it
>> NX.
>>
>> Without this patch, an attacker who can force a daemon to call some
>> fixed address could wait until the time contains, say, 0xCD80, and
>> then execute the current time.
>>
>> Signed-off-by: Andy Lutomirski <luto@xxxxxxx>
>> ---
>>  arch/x86/include/asm/fixmap.h        |    1 +
>>  arch/x86/include/asm/pgtable_types.h |    2 ++
>>  arch/x86/include/asm/vvar.h          |   22 ++++++++++------------
>>  arch/x86/kernel/vmlinux.lds.S        |   27 ++++++++++++++++-----------
>>  arch/x86/kernel/vsyscall_64.c        |    5 +++++
>>  tools/power/x86/turbostat/turbostat  |  Bin 0 -> 29200 bytes
>
> You've added the turbostat binary to the diffstat too. I believe this
> wasn't your intention, no? :)

Foiled again!

--Andy
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