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

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Date:   Tue, 15 Mar 2022 18:02:49 +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

Hi Konstantin,

This series looks good! Thanks for the split in multiple patches.


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.

>   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.

> 
> 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):

You can build statically-linked tests with:
make -C tools/testing/selftests/landlock CFLAGS=-static

> 1. base_test: 7/8 tests passed.
>   Error:
>   # Starting 8 tests from 1 test cases.
>   #  RUN           global.inconsistent_attr ...
>   # base_test.c:51:inconsistent_attr:Expected ENOMSG (42) == errno (22)

This looks like a bug in the syscall argument checks.

>   # inconsistent_attr: Test terminated by assertion
> 2. fs_test: 0 / 46 tests passed
>   Error for all tests:
>   # common.h:126:no_restriction:Expected -1 (-1) != cap_set_proc(cap_p) (-1)
>   # common.h:127:no_restriction:Failed to cap_set_proc: Operation not permitted
>   # fs_test.c:106:no_restriction:Expected 0 (0) == mkdir(path, 0700) (-1)
>   # fs_test.c:107:no_restriction:Failed to create directory "tmp": File exists

You need to run these tests as root.

> 3. ptrace_test: 4 / 8 tests passed.
> 
> Previous versions:
> v3: https://lore.kernel.org/linux-security-module/20220124080215.265538-1-konstantin.meskhidze@huawei.com/
> v2: https://lore.kernel.org/linux-security-module/20211228115212.703084-1-konstantin.meskhidze@huawei.com/
> v1: https://lore.kernel.org/linux-security-module/20211210072123.386713-1-konstantin.meskhidze@huawei.com/

Nice to have this history!

> 
> Konstantin Meskhidze (15):
>    landlock: access mask renaming
>    landlock: filesystem access mask helpers
>    landlock: landlock_find/insert_rule refactoring
>    landlock: merge and inherit function refactoring
>    landlock: unmask_layers() function refactoring
>    landlock: landlock_add_rule syscall refactoring
>    landlock: user space API network support
>    landlock: add support network rules
>    landlock: TCP network hooks implementation
>    seltest/landlock: add tests for bind() hooks
>    seltest/landlock: add tests for connect() hooks
>    seltest/landlock: connect() with AF_UNSPEC tests
>    seltest/landlock: rules overlapping test
>    seltest/landlock: ruleset expanding test
>    seltest/landlock: invalid user input data test
> 
>   include/uapi/linux/landlock.h                 |  48 ++
>   security/landlock/Kconfig                     |   1 +
>   security/landlock/Makefile                    |   2 +-
>   security/landlock/fs.c                        |  72 +-
>   security/landlock/limits.h                    |   6 +
>   security/landlock/net.c                       | 180 +++++
>   security/landlock/net.h                       |  22 +
>   security/landlock/ruleset.c                   | 383 ++++++++--
>   security/landlock/ruleset.h                   |  72 +-
>   security/landlock/setup.c                     |   2 +
>   security/landlock/syscalls.c                  | 176 +++--
>   .../testing/selftests/landlock/network_test.c | 665 ++++++++++++++++++
>   12 files changed, 1434 insertions(+), 195 deletions(-)
>   create mode 100644 security/landlock/net.c
>   create mode 100644 security/landlock/net.h
>   create mode 100644 tools/testing/selftests/landlock/network_test.c
> 
> --
> 2.25.1
>