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From:   Andrii Nakryiko <andrii.nakryiko@gmail.com>
Date:   Wed, 25 Mar 2020 19:01:00 -0700
Message-ID: <CAEf4BzbzfbTT9x3tfLrqhYgozcvxvHvKSVkvyuNqji=aNgvmZg@mail.gmail.com>
Subject: Re: [PATCH bpf-next v6 7/8] bpf: lsm: Add selftests for BPF_PROG_TYPE_LSM
To:     KP Singh <kpsingh@chromium.org>
Cc:     open list <linux-kernel@vger.kernel.org>,
        bpf <bpf@vger.kernel.org>, linux-security-module@vger.kernel.org,
        Brendan Jackman <jackmanb@google.com>,
        Florent Revest <revest@google.com>,
        Thomas Garnier <thgarnie@google.com>,
        Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        James Morris <jmorris@namei.org>,
        Kees Cook <keescook@chromium.org>,
        Paul Turner <pjt@google.com>, Jann Horn <jannh@google.com>,
        Florent Revest <revest@chromium.org>,
        Brendan Jackman <jackmanb@chromium.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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On Wed, Mar 25, 2020 at 8:27 AM KP Singh <kpsingh@chromium.org> wrote:
>
> From: KP Singh <kpsingh@google.com>
>
> * Load/attach a BPF program that hooks to file_mprotect (int)
>   and bprm_committed_creds (void).
> * Perform an action that triggers the hook.
> * Verify if the audit event was received using the shared global
>   variables for the process executed.
> * Verify if the mprotect returns a -EPERM.
>
> Signed-off-by: KP Singh <kpsingh@google.com>
> Reviewed-by: Brendan Jackman <jackmanb@google.com>
> Reviewed-by: Florent Revest <revest@google.com>
> Reviewed-by: Thomas Garnier <thgarnie@google.com>
> ---
>  tools/testing/selftests/bpf/config            |  2 +
>  .../selftests/bpf/prog_tests/test_lsm.c       | 84 +++++++++++++++++++
>  tools/testing/selftests/bpf/progs/lsm.c       | 48 +++++++++++
>  3 files changed, 134 insertions(+)
>  create mode 100644 tools/testing/selftests/bpf/prog_tests/test_lsm.c
>  create mode 100644 tools/testing/selftests/bpf/progs/lsm.c
>

[...]

> +
> +int exec_cmd(int *monitored_pid)
> +{
> +       int child_pid;
> +
> +       child_pid = fork();
> +       if (child_pid == 0) {
> +               *monitored_pid = getpid();
> +               execvp(CMD_ARGS[0], CMD_ARGS);
> +               return -EINVAL;
> +       } else if (child_pid > 0)

This test is part of test_progs, so let's be a good citizen and wait
for your specific child. I'd rather not hunt for elusive bugs later,
so please use waitpid() instead.

Otherwise looks good and clean, thanks!

> +               return wait(NULL);
> +
> +       return -EINVAL;
> +}
> +

[...]