Date:   Thu, 24 Mar 2022 13:27:04 +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 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 got the next result:
> " Capturing coverage data from ./landlock
> Found gcov version: 9.4.0
> Using intermediate gcov format
> Scanning ./landlock for .gcda files ...
> Found 7 data files in ./landlock
> Processing landlock/setup.gcda
> /home/kmeskhidze/work/src/gcov_before/landlock/setup.gcda:cannot open 
> data file, assuming not executed
> Processing landlock/object.gcda
> /home/kmeskhidze/work/src/gcov_before/landlock/object.gcda:cannot open 
> data file, assuming not executed
> Processing landlock/cred.gcda
> /home/kmeskhidze/work/src/gcov_before/landlock/cred.gcda:cannot open 
> data file, assuming not executed
> Processing landlock/ruleset.gcda
> /home/kmeskhidze/work/src/gcov_before/landlock/ruleset.gcda:cannot open 
> data file, assuming not executed
> Processing landlock/syscalls.gcda
> /home/kmeskhidze/work/src/gcov_before/landlock/syscalls.gcda:cannot open 
> data file, assuming not executed
> Processing landlock/fs.gcda
> /home/kmeskhidze/work/src/gcov_before/landlock/fs.gcda:cannot open data 
> file, assuming not executed
> Processing landlock/ptrace.gcda
> /home/kmeskhidze/work/src/gcov_before/landlock/ptrace.gcda:cannot open 
> data file, assuming not executed
> Finished .info-file creation
> Reading data file lcov.info
> Found 38 entries.
> Found common filename prefix 
> "/home/kmeskhidze/work/src/linux_5.13_landlock"
> Writing .css and .png files.
> Generating output.
> Processing file arch/x86/include/asm/atomic64_64.h
> Processing file arch/x86/include/asm/bitops.h
> Processing file arch/x86/include/asm/atomic.h
> Processing file arch/x86/include/asm/current.h
> Processing file include/asm-generic/getorder.h
> Processing file include/asm-generic/bitops/instrumented-non-atomic.h
> Processing file include/linux/fs.h
> Processing file include/linux/refcount.h
> Processing file include/linux/kernel.h
> Processing file include/linux/list.h
> Processing file include/linux/sched.h
> Processing file include/linux/overflow.h
> Processing file include/linux/dcache.h
> Processing file include/linux/spinlock.h
> Processing file include/linux/file.h
> Processing file include/linux/rcupdate.h
> Processing file include/linux/err.h
> Processing file include/linux/workqueue.h
> Processing file include/linux/fortify-string.h
> Processing file include/linux/slab.h
> Processing file include/linux/instrumented.h
> Processing file include/linux/uaccess.h
> Processing file include/linux/thread_info.h
> Processing file include/linux/rbtree.h
> Processing file include/linux/log2.h
> Processing file include/linux/atomic/atomic-instrumented.h
> Processing file include/linux/atomic/atomic-long.h
> Processing file security/landlock/fs.c
> Processing file security/landlock/ruleset.h
> Processing file security/landlock/ruleset.c
> Processing file security/landlock/ptrace.c
> Processing file security/landlock/object.h
> Processing file security/landlock/syscalls.c
> Processing file security/landlock/setup.c
> Processing file security/landlock/cred.c
> Processing file security/landlock/object.c
> Processing file security/landlock/fs.h
> Processing file security/landlock/cred.h
> Writing directory view page.
> Overall coverage rate:
>    lines......: 0.0% (0 of 937 lines)
>    functions..: 0.0% (0 of 67 functions) "
> 
> Looks like .gcda files were not executed.
> Maybe I did miss something. Any thoughts?

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