linux-kernel - Re: [PATCH next 3/3] selftests:connector: Add root check and fix arg error paths to skip

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Message-ID: <8c92599f-fcb4-3aba-f367-17abd9b52451@linuxfoundation.org>
Date:   Fri, 28 Jul 2023 17:00:05 -0600
From:   Shuah Khan <skhan@...uxfoundation.org>
To:     Anjali Kulkarni <anjali.k.kulkarni@...cle.com>
Cc:     Shuah Khan <shuah@...nel.org>,
        Liam Howlett <liam.howlett@...cle.com>,
        "kuba@...nel.org" <kuba@...nel.org>,
        "davem@...emloft.net" <davem@...emloft.net>,
        "linux-kselftest@...r.kernel.org" <linux-kselftest@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Shuah Khan <skhan@...uxfoundation.org>
Subject: Re: [PATCH next 3/3] selftests:connector: Add root check and fix arg
 error paths to skip

On 7/28/23 16:40, Anjali Kulkarni wrote:
> 
> 
>> On Jul 28, 2023, at 3:25 PM, Shuah Khan <skhan@...uxfoundation.org> wrote:
>>
>> On 7/28/23 15:59, Anjali Kulkarni wrote:
>>>> On Jul 28, 2023, at 2:41 PM, Shuah Khan <skhan@...uxfoundation.org> wrote:
>>>>
>>>> On 7/28/23 15:21, Anjali Kulkarni wrote:
>>>>>> On Jul 28, 2023, at 12:44 PM, Shuah Khan <skhan@...uxfoundation.org> wrote:
>>>>>>
>>>>>> On 7/28/23 13:06, Shuah Khan wrote:
>>>>>>> On 7/28/23 12:10, Anjali Kulkarni wrote:
>>>>>>>>
>>>>>>>>
>>>>>>>>> On Jul 28, 2023, at 10:29 AM, Shuah Khan <skhan@...uxfoundation.org> wrote:
>>>>>>>>>
>>>>>>>>> proc_filter test requires root privileges. Add root privilege check
>>>>>>>>> and skip the test. Also fix argument parsing paths to skip in their
>>>>>>>>> error legs.
>>>>>>>>>
>>>>>>>>> Signed-off-by: Shuah Khan <skhan@...uxfoundation.org>
>>>>>>>>> ---
>>>>>>>>> tools/testing/selftests/connector/proc_filter.c | 9 +++++++--
>>>>>>>>> 1 file changed, 7 insertions(+), 2 deletions(-)
>>>>>>>>>
>>>>>>>>> diff --git a/tools/testing/selftests/connector/proc_filter.c b/tools/testing/selftests/connector/proc_filter.c
>>>>>>>>> index 4fe8c6763fd8..7b2081b98e5c 100644
>>>>>>>>> --- a/tools/testing/selftests/connector/proc_filter.c
>>>>>>>>> +++ b/tools/testing/selftests/connector/proc_filter.c
>>>>>>>>> @@ -248,7 +248,7 @@ int main(int argc, char *argv[])
>>>>>>>>>
>>>>>>>>> if (argc > 2) {
>>>>>>>>> printf("Expected 0(assume no-filter) or 1 argument(-f)\n");
>>>>>>>>> - exit(1);
>>>>>>>>> + exit(KSFT_SKIP);
>>>>>>>>> }
>>>>>>>>>
>>>>>>>>> if (argc == 2) {
>>>>>>>>> @@ -256,10 +256,15 @@ int main(int argc, char *argv[])
>>>>>>>>> filter = 1;
>>>>>>>>> } else {
>>>>>>>>> printf("Valid option : -f (for filter feature)\n");
>>>>>>>>> - exit(1);
>>>>>>>>> + exit(KSFT_SKIP);
>>>>>>>>> }
>>>>>>>>> }
>>>>>>>>>
>>>>>>>>> + if (geteuid()) {
>>>>>>>>> + printf("Connector test requires root privileges.\n");
>>>>>>>>> + exit(KSFT_SKIP);
>>>>>>>>> + }
>>>>>>>>> +
>>>>>>>>
>>>>>>>> I am not sure why you have added this check? proc_filter does not need root privilege to run.
>>>>>>>>
>>>>>>> It failed for me when I ran it saying it requires root privileges.
>>>>>>> I had to run it as root.
>>>>>>
>>>>>> The following is what I see when I run the test as non-root
>>>>>> user:
>>>>>>
>>>>>> bind failed: Operation not permitted
>>>>>>
>>>>> Yes, that’s expected on a kernel which does not have the kernel patches submitted with this selftest installed on it.
>>>>> So this check for root needs to be removed.
>>>>
>>>> I will send v2 for this patch without root check. I should have
>>>> split the argument error paths and root check anyway.
>>>>
>>>> However, what is strange is if the test run by root, bind() doesn't fail.
>>>> This doesn't make sense to me based on what you said about bind() fails
>>>> if kernel doesn't support the new feature.
>>>>
>>> I didn’t say that - part of the changes introduced by the patches is to remove the root check and add some features on top of existing code.
>>
>> Okay. So what should happen if a root user runs this test on a kernel
>> that doesn't have the kernel patches submitted with this selftest
>> installed on it?
>>
> 
> It will default to the behavior previous to my changes - that is it will report all events as opposed to a subset of events (which is the new feature added by my change)
> 

Okay. Sorry I am unable to follow this explanation. This test has just
been added in commit 73a29531f45fed6423144057d7a844aae46dad9d

Can you please look at the usage for this test:

- What should happen when kernel without filtering is run as
   root or non-root
- What should happen when kernel with filtering is run as
   root or non-root

There seems to be difference in behavior of this test depending
on user privileges. This should reflect in the message the user
sees.

This message "bind failed: Operation not permitted" doesn't tell
user anything - add a better message. Also this needs to be a skip
and not fail.

I just sent v2 without the root check.

thanks,
-- Shuah