linux-kernel - Re: [PATCH] hpet, allow user controlled mmap for user processes

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Date:	Thu, 12 Sep 2013 20:00:59 -0400
From:	Prarit Bhargava <prarit@...hat.com>
To:	Matt Wilson <msw@...zon.com>
CC:	linux-kernel@...r.kernel.org, Clemens Ladisch <clemens@...isch.de>
Subject: Re: [PATCH] hpet, allow user controlled mmap for user processes



On 08/29/2013 02:01 AM, Matt Wilson wrote:
> On Fri, Mar 22, 2013 at 09:32:54AM -0400, Prarit Bhargava wrote:
>> The CONFIG_HPET_MMAP Kconfig option exposes the memory map of the HPET
>> registers to userspace.  The Kconfig help points out that in some cases this
>> can be a security risk as some systems may erroneously configure the map such
>> that additional data is exposed to userspace.
>>
>> This is a problem for distributions -- some users want the MMAP functionality
>> but it comes with a significant security risk.  In an effort to mitigate this
>> risk, and due to the low number of users of the MMAP functionality, I've
>> introduced a kernel parameter, hpet_mmap_enable, that is required in order
>> to actually have the HPET MMAP exposed.
>>
>> [v2]: Clemens suggested modifying the Kconfig help text and making the
>> default setting configurable.
>> [v3]: Fixed up Documentation and Kconfig entries, default now "Y"
>> [v4]: After testing, found that I need to modify CONFIG_HPET_MMAP_DEFAULT usage
>>
>> Signed-off-by: Prarit Bhargava <prarit@...hat.com>
>> Cc: Clemens Ladisch <clemens@...isch.de>
>> ---
>>  Documentation/kernel-parameters.txt |    4 ++++
>>  drivers/char/Kconfig                |    9 +++++++--
>>  drivers/char/hpet.c                 |   25 +++++++++++++++++++++++--
>>  3 files changed, 34 insertions(+), 4 deletions(-)
> 
> It doesn't seem like this patch got picked up and seems like a good
> idea to me. Clemens, what do you think?
> 
> Acked-by: Matt Wilson <msw@...zon.com>
> 

Clemens?  I didn't see a reply...

P.
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