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From:   Jeff Xu <jeffxu@google.com>
Date:   Wed, 30 Nov 2022 11:47:18 -0800
Message-ID: <CALmYWFs0GG8o3WQw7PEGvT=qgHHGiTC_mE1kQ0oRVjNUJa36gA@mail.gmail.com>
Subject: Re: [PATCH -next] selftests/landlock: Fix selftest ptrace_test run fail
To:     =?UTF-8?B?TWlja2HDq2wgU2FsYcO8bg==?= <mic@digikod.net>
Cc:     limin <limin100@huawei.com>, hannes@cmpxchg.org, mhocko@kernel.org,
        roman.gushchin@linux.dev, shakeelb@google.com,
        songmuchun@bytedance.com, tj@kernel.org, lizefan.x@bytedance.com,
        shuah@kernel.org, linux-kselftest@vger.kernel.org,
        linux-security-module@vger.kernel.org,
        linux-kernel@vger.kernel.org,
        Jorge Lucangeli Obes <jorgelo@chromium.org>,
        Guenter Roeck <groeck@chromium.org>,
        Kees Cook <keescook@chromium.org>
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On Wed, Nov 30, 2022 at 11:32 AM Micka=C3=ABl Sala=C3=BCn <mic@digikod.net>=
 wrote:
>
> I checked and the Landlock ptrace test failed because Yama is enabled,
> which is expected. You can check that with
> /proc/sys/kernel/yama/ptrace_scope
>
> Jeff Xu sent a patch to fix this case but it is not ready yet:
> https://lore.kernel.org/r/20220628222941.2642917-1-jeffxu@google.com
>
> Could you please send a new patch Jeff, and add Limin in Cc?
>
Yes. This work is planned for Dec. I will start working on it soon.
Jeff

>
> On 29/11/2022 12:26, limin wrote:
> > cat /proc/cmdline
> > BOOT_IMAGE=3D/vmlinuz-6.1.0-next-20221116
> > root=3DUUID=3Da65b3a79-dc02-4728-8a0c-5cf24f4ae08b ro
> > systemd.unified_cgroup_hierarchy=3D1 cgroup_no_v1=3Dall
> >
> >
> > config
> >
> > #
> > # Automatically generated file; DO NOT EDIT.
> > # Linux/x86 6.1.0-rc6 Kernel Configuration
> > #
>
> [...]
>
> > CONFIG_SECURITY_YAMA=3Dy
>
> [...]
>
> > CONFIG_LSM=3D"landlock,lockdown,yama,integrity,apparmor"
> [...]
> >
> > On 2022/11/29 19:03, Micka=C3=ABl Sala=C3=BCn wrote:
> >> I tested with next-20221116 and all tests are OK. Could you share your
> >> kernel configuration with a link? What is the content of /proc/cmdline=
?
> >>
> >> On 29/11/2022 02:42, limin wrote:
> >>> I run test on Linux ubuntu2204 6.1.0-next-20221116
> >>>
> >>> I did't use yama.
> >>>
> >>> you can reproduce by this step:
> >>>
> >>> cd kernel_src
> >>>
> >>> cd tools/testing/selftests/landlock/
> >>> make
> >>> ./ptrace_test
> >>>
> >>>
> >>>
> >>>
> >>> On 2022/11/29 3:44, Micka=C3=ABl Sala=C3=BCn wrote:
> >>>> This patch changes the test semantic and then cannot work on my test
> >>>> environment. On which kernel did you run test? Do you use Yama or
> >>>> something similar?
> >>>>
> >>>> On 28/11/2022 03:04, limin wrote:
> >>>>> Tests PTRACE_ATTACH and PTRACE_MODE_READ on the parent,
> >>>>> trace parent return -1 when child=3D=3D 0
> >>>>> How to reproduce warning:
> >>>>> $ make -C tools/testing/selftests TARGETS=3Dlandlock run_tests
> >>>>>
> >>>>> Signed-off-by: limin <limin100@huawei.com>
> >>>>> ---
> >>>>>     tools/testing/selftests/landlock/ptrace_test.c | 5 ++---
> >>>>>     1 file changed, 2 insertions(+), 3 deletions(-)
> >>>>>
> >>>>> diff --git a/tools/testing/selftests/landlock/ptrace_test.c
> >>>>> b/tools/testing/selftests/landlock/ptrace_test.c
> >>>>> index c28ef98ff3ac..88c4dc63eea0 100644
> >>>>> --- a/tools/testing/selftests/landlock/ptrace_test.c
> >>>>> +++ b/tools/testing/selftests/landlock/ptrace_test.c
> >>>>> @@ -267,12 +267,11 @@ TEST_F(hierarchy, trace)
> >>>>>             /* Tests PTRACE_ATTACH and PTRACE_MODE_READ on the
> >>>>> parent. */
> >>>>>             err_proc_read =3D test_ptrace_read(parent);
> >>>>>             ret =3D ptrace(PTRACE_ATTACH, parent, NULL, 0);
> >>>>> +        EXPECT_EQ(-1, ret);
> >>>>> +        EXPECT_EQ(EPERM, errno);
> >>>>>             if (variant->domain_child) {
> >>>>> -            EXPECT_EQ(-1, ret);
> >>>>> -            EXPECT_EQ(EPERM, errno);
> >>>>>                 EXPECT_EQ(EACCES, err_proc_read);
> >>>>>             } else {
> >>>>> -            EXPECT_EQ(0, ret);
> >>>>>                 EXPECT_EQ(0, err_proc_read);
> >>>>>             }
> >>>>>             if (ret =3D=3D 0) {