netdev - Re: [RFC PATCH 2/2] landlock: selftests for bind and connect hooks

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Date:   Thu, 24 Feb 2022 10:55:09 +0100
From:   Mickaël Salaün <mic@...ikod.net>
To:     Konstantin Meskhidze <konstantin.meskhidze@...wei.com>
Cc:     linux-security-module@...r.kernel.org, netdev@...r.kernel.org,
        netfilter@...r.kernel.org, yusongping@...wei.com,
        artem.kuzin@...wei.com
Subject: Re: [RFC PATCH 2/2] landlock: selftests for bind and connect hooks


On 24/02/2022 04:18, Konstantin Meskhidze wrote:
> 
> 
> 2/1/2022 9:31 PM, Mickaël Salaün пишет:
>>
>> On 24/01/2022 09:02, Konstantin Meskhidze wrote:
>>> Support 4 tests for bind and connect networks actions:
>>
>> Good to see such tests!
>>
>>
>>> 1. bind() a socket with no landlock restrictions.
>>> 2. bind() sockets with landllock restrictions.
>>
>> You can leverage the FIXTURE_VARIANT helpers to factor out this kind 
>> of tests (see ptrace_test.c).
>>
>>
>>> 3. connect() a socket to listening one with no landlock restricitons.
>>> 4. connect() sockets with landlock restrictions.
>>
>> Same here, you can factor out code. I guess you could create helpers 
>> for client and server parts.
>>
>> We also need to test with IPv4, IPv6 and the AF_UNSPEC tricks.
>>
>> Please provide the kernel test coverage and explain why the uncovered 
>> code cannot be covered: 
>> https://www.kernel.org/doc/html/latest/dev-tools/gcov.html
> 
>   Hi Mickaёl!
>   Could you please provide the example of your test coverage build
>   process? Cause as I undersatand there is no need to get coverage data
>   for the entire kernel, just for landlock files.

You just need to follow the documentation:
- start the VM with the kernel appropriately configured for coverage;
- run all the Landlock tests;
- gather the coverage and shutdown the VM;
- use lcov and genhtml to create the web pages;
- look at the coverage for security/landlock/

>>
>> You'll probably see that there are a multiple parts of the kernel that 
>> are not covered. For instance, it is important to test different 
>> combinations of layered network rules (see layout1/ruleset_overlap, 
>> layer_rule_unions, non_overlapping_accesses, 
>> interleaved_masked_accesses… in fs_test.c). Tests in fs_test.c are 
>> more complex because handling file system rules is more complex, but 
>> you can get some inspiration in it, especially the edge cases.
>>
>> We also need to test invalid user space supplied data (see 
>> layout1/inval test in fs_test.c).