Re: [PATCH v3 1/6] io_uring/mock: add basic infra for test mock files

[Pavel Begunkov <asml.silence@gmail.com>]

On 5/30/25 12:48, Jens Axboe wrote:
> On 5/30/25 5:45 AM, Pavel Begunkov wrote:
>> On 5/30/25 12:31, Jens Axboe wrote:
>>> On 5/30/25 2:38 AM, Pavel Begunkov wrote:
>>>> io_uring commands provide an ioctl style interface for files to
>>>> implement file specific operations. io_uring provides many features and
>>>> advanced api to commands, and it's getting hard to test as it requires
>>>> specific files/devices.
>>>>
>>>> Add basic infrastucture for creating special mock files that will be
>>>> implementing the cmd api and using various io_uring features we want to
>>>> test. It'll also be useful to test some more obscure read/write/polling
>>>> edge cases in the future.
>>>
>>> Do we want to have the creation of a mock file be a privileged
>>> operation?
>>
>> It doesn't do anything that would warrant that, maybe just yet.
>> Do you mean from the security perspective? i.e. making sure a
>> user can't exploit it if there is anything to be exploited.
>> I'd really hope nobody would compile this thing for non-test
>> kernels. Maybe I should make it dependent on lockdep to enforce
>> it.
> 
> People do all sorts of weird stuff. I know it doesn't do anything
> that warrants making it root only, but at least as root only, any
> side effects will be limited to that. I think that'd be better than
> making it forcibly depend on something unrelated (but debug'y) like
> lockdep.

I don't hate the CAP_ADMIN idea, I'll add it, but making it
dependent on something incompatible with production kernels is
the only way to ensure it's used in the intended way.

-- 
Pavel Begunkov