Re: [PATCH 3/3 V13] RO/NX protection for loadable kernel

[Xiaotian Feng]

On Fri, Jan 21, 2011 at 4:32 AM, matthieu castet
<castet.matthieu@xxxxxxx> wrote:
> Xiaotian Feng a Ãcrit :
>>
>> On Thu, Dec 23, 2010 at 5:35 AM, Â<Valdis.Kletnieks@xxxxxx> wrote:
>>>
>>> On Wed, 22 Dec 2010 13:40:19 +0100, Ingo Molnar said:
>>>>
>>>> * mat <castet.matthieu@xxxxxxx> wrote:
>>>>
>>>>> Le Wed, 8 Dec 2010 14:19:51 -0800,
>>>>> Kees Cook <kees.cook@xxxxxxxxxxxxx> a Ãcrit :
>>>>>
>>>>>> On Fri, Nov 26, 2010 at 06:23:55PM +0100, mat wrote:
>>>>>>>
>>>>>>> could you try the attached patch ?
>>>>>>>
>>>>>>> on module load, we sort the __jump_table section. So we should make
>>>>>>> it writable.
>>>>>>>
>>>>>>>
>>>>>>> Matthieu
>>>>>>> diff --git a/arch/x86/include/asm/jump_label.h
>>>>>>> b/arch/x86/include/asm/jump_label.h index f52d42e..574dbc2 100644
>>>>>>> --- a/arch/x86/include/asm/jump_label.h
>>>>>>> +++ b/arch/x86/include/asm/jump_label.h
>>>>>>> @@ -14,7 +14,7 @@
>>>>>>> Â Â Â Âdo
>>>>>>> { Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â \ asm
>>>>>>> goto("1:" Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â \
>>>>>>> JUMP_LABEL_INITIAL_NOP Â Â Â Â Â Â Â Â Â\
>>>>>>> - Â Â Â Â Â Â Â Â Â Â Â ".pushsection __jump_table, Â\"a\" \n\t"\
>>>>>>> + Â Â Â Â Â Â Â Â Â Â Â ".pushsection __jump_table, Â\"aw\" \n\t"\
>>>>>>> Â Â Â Â Â Â Â Â Â Â Â Â_ASM_PTR "1b, %l[" #label "], %c0 \n\t" \
>>>>>>> Â Â Â Â Â Â Â Â Â Â Â Â".popsection \n\t" Â Â Â Â Â Â Â Â Â Â Â\
>>>>>>> Â Â Â Â Â Â Â Â Â Â Â Â: : Â"i" (key) : Â: label);
>>>>>>> \
>>>>>>
>>>>>> Acked-by: Kees Cook <kees.cook@xxxxxxxxxxxxx>
>>>>>>
>>>>>> Can this please get committed to tip?
>>>>>
>>>>> I think it is not need anymore with ÂSteven Rostedt patch [1]
>>>>>
>>>>> Matthieu
>>>>>
>>>>> [1]
>>>>>>>
>>>>>>> Here we set the text read only before we call the notifiers. The
>>>>>>> function tracer changes the calls to mcount into nops via a notifier
>>>>>>> call so this must be done after the module notifiers.
>>>>
>>>> What's the status of this bug?
>>>>
>>>> If we still need the patch then please submit it standalone with a
>>>> proper subject
>>>> line, with acks/signoffs added, etc.
>>>
>>> Steve Rostedt's patch that moves the setting of the page permissions
>>> seems to
>>> make this patch no longer necessary. ÂI tripped over this same issue, but
>>> the
>>> version in the latest -mmotm does not need it, as it includes Steve's
>>> fix.
>>>
>>
>> I'm facing a boot failure (panic'ed on remove_jump_label_module_init)
>> on 2.6.37 (latest commit 3c0cb7c), which is 100% reproducible.
>> With this patch applied, I can boot my machine successfully, so I do
>> think this patch is needed.
>>
> Could you confirm that this patch fix the problem ?
>

Yes, I already applied this patch, and my system works fine now.

>
> Matthieu
>
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