Re: [PATCH] kconfig: Add kernel config option for fuzz testing.

[Tetsuo Handa]

On 2020/02/18 19:54, Tetsuo Handa wrote:
> On 2020/01/03 4:57, Matthew Garrett wrote:
>> On Tue, Dec 17, 2019 at 12:53 AM Dmitry Vyukov <dvyukov@xxxxxxxxxx> wrote:
>>> +Matthew for a lockdown question
>>> We are considering [ab]using lockdown (you knew this will happen!) for
>>> fuzzing kernel. LOCKDOWN_DEBUGFS is a no-go for us and we may want a
>>> few other things that may be fuzzing-specific.
>>> The current inflexibility comes from the global ordering of levels:
>>>
>>> if (kernel_locked_down >= level)
>>> if (kernel_locked_down >= what) {
>>>
>>> Is it done for performance? Or for simplicity?
>>
>> Simplicity. Based on discussion, we didn't want the lockdown LSM to
>> enable arbitrary combinations of lockdown primitives, both because
>> that would make it extremely difficult for userland developers and
>> because it would make it extremely easy for local admins to
>> accidentally configure policies that didn't achieve the desired
>> outcome. There's no inherent problem in adding new options, but really
>> right now they should fall into cases where they're protecting either
>> the integrity of the kernel or preventing leakage of confidential
>> information from the kernel.
>>
> 
> Can we resume this topic?
> 
> I think build-time lockdown (i.e. kernel config option) is more reliable
> and easier to use.
> 

Here is an example of need to lockdown specific ations. Can we proceed?

https://lkml.kernel.org/r/CACT4Y+azQXLcPqtJG9zbj8hxqw4jE3dcwUj5T06bdL3uMaZk+Q@xxxxxxxxxxxxxx