netdev - Re: [RFC PATCH v4 00/15] Landlock LSM

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Message-ID: <3a33baf2-3de7-fecd-29d3-715500e3631f@digikod.net>
Date:   Thu, 24 Mar 2022 16:30:10 +0100
From:   Mickaël Salaün <mic@...ikod.net>
To:     Konstantin Meskhidze <konstantin.meskhidze@...wei.com>
Cc:     willemdebruijn.kernel@...il.com,
        linux-security-module@...r.kernel.org, netdev@...r.kernel.org,
        netfilter-devel@...r.kernel.org, yusongping@...wei.com,
        artem.kuzin@...wei.com, anton.sirazetdinov@...wei.com
Subject: Re: [RFC PATCH v4 00/15] Landlock LSM



On 24/03/2022 14:34, Konstantin Meskhidze wrote:
> 
> 
> 3/24/2022 3:27 PM, Mickaël Salaün пишет:
>>
>> On 23/03/2022 17:30, Konstantin Meskhidze wrote:
>>>
>>>
>>> 3/17/2022 8:26 PM, Mickaël Salaün пишет:
>>>>
>>>> On 17/03/2022 14:01, Konstantin Meskhidze wrote:
>>>>>
>>>>>
>>>>> 3/15/2022 8:02 PM, Mickaël Salaün пишет:
>>>>>> Hi Konstantin,
>>>>>>
>>>>>> This series looks good! Thanks for the split in multiple patches.
>>>>>>
>>>>>   Thanks. I follow your recommendations.
>>>>>>
>>>>>> On 09/03/2022 14:44, Konstantin Meskhidze wrote:
>>>>>>> Hi,
>>>>>>> This is a new V4 bunch of RFC patches related to Landlock LSM 
>>>>>>> network confinement.
>>>>>>> It brings deep refactirong and commit splitting of previous 
>>>>>>> version V3.
>>>>>>> Also added additional selftests.
>>>>>>>
>>>>>>> This patch series can be applied on top of v5.17-rc3.
>>>>>>>
>>>>>>> All test were run in QEMU evironment and compiled with
>>>>>>>   -static flag.
>>>>>>>   1. network_test: 9/9 tests passed.
>>>>>>
>>>>>> I get a kernel warning running the network tests.
>>>>>
>>>>>    What kind of warning? Can you provide it please?
>>>>
>>>> You really need to get a setup that gives you such kernel warning. 
>>>> When running network_test you should get:
>>>> WARNING: CPU: 3 PID: 742 at security/landlock/ruleset.c:218 
>>>> insert_rule+0x220/0x270
>>>>
>>>> Before sending new patches, please make sure you're able to catch 
>>>> such issues.
>>>>
>>>>
>>>>>>
>>>>>>>   2. base_test: 8/8 tests passed.
>>>>>>>   3. fs_test: 46/46 tests passed.
>>>>>>>   4. ptrace_test: 4/8 tests passed.
>>>>>>
>>>>>> Does your test machine use Yama? That would explain the 4/8. You 
>>>>>> can disable it with the appropriate sysctl.
>>>>
>>>> Can you answer this question?
>>>>
>>>>
>>>>>>
>>>>>>>
>>>>>>> Tests were also launched for Landlock version without
>>>>>>> v4 patch:
>>>>>>>   1. base_test: 8/8 tests passed.
>>>>>>>   2. fs_test: 46/46 tests passed.
>>>>>>>   3. ptrace_test: 4/8 tests passed.
>>>>>>>
>>>>>>> Could not provide test coverage cause had problems with tests
>>>>>>> on VM (no -static flag the tests compiling, no v4 patch applied):
>>>>>>
>>>     Hi, Mickaёl!
>>>     I tried to get base test coverage without v4 patch applied.
>>>
>>>     1. Kernel configuration :
>>>      - CONFIG_DEBUG_FS=y
>>>      - CONFIG_GCOV_KERNEL=y
>>>      - CONFIG_ARCH_HAS_GCOV_PROFILE_ALL=y
>>>     2. Added GCOV_PROFILE := y in security/landlock/Makefile
>>
>> I think this is useless because of CONFIG_ARCH_HAS_GCOV_PROFILE_ALL=y. 
>> I don't add GCOV_PROFILE anyway.
>>
>>
>>>     3. Compiled kernel  and rebooted VM with the new one.
>>>     4. Run landlock selftests as root user:
>>>      $ cd tools/testing/selftests/landlock
>>>      $ ./base_test
>>>      $ ./fs_test
>>>      $ ./ptrace_test
>>>     5. Copied GCOV data to some folder :
>>>        $ cp -r 
>>> /sys/kernel/debug/gcov/<source-dir>/linux/security/landlock/ 
>>> /gcov-before
>>>        $ cd /gcov-before
>>>        $ lcov -c -d ./landlock -o lcov.info && genhtml -o html lcov.info
>>
>> I do this step on my host but that should work as long as you have the 
>> kernel sources in the same directory. I guess this is not the case. I 
>> think you also need GCC >= 4.8 .
>>    I found the reason why .gcda files were not executed :
>        "lcov -c -d ./landlock -o lcov.info && genhtml -o html lcov.info" 
> was run not under ROOT user.
>    Running lcov by ROOT one solved the issue. I will provide network test
>    coverage in RFC patch V5.
>    Thanks for help anyway.

I run lcov as a normal user with kernel source access.

I'll review the other patches soon. But for the next series, please 
don't reuse "Landlock LSM" as a cover letter subject, something like 
"Network support for Landlock" would fit better. ;)