Re: [PATCH 4/4] selftests/seccomp: Test SECCOMP_LOAD_FILTER and SECCOMP_ATTACH_FILTER

[Kees Cook]

On Mon, Oct 09, 2023 at 12:40:46PM +0000, Hengqi Chen wrote:
> Add a testcase to exercise the newly added SECCOMP_LOAD_FILTER
> and SECCOMP_ATTACH_FILTER operations.
> 
> Signed-off-by: Hengqi Chen <hengqi.chen@xxxxxxxxx>
> ---
>  tools/testing/selftests/seccomp/seccomp_bpf.c | 20 +++++++++++++++++++
>  1 file changed, 20 insertions(+)
> 
> diff --git a/tools/testing/selftests/seccomp/seccomp_bpf.c b/tools/testing/selftests/seccomp/seccomp_bpf.c
> index 38f651469968..8f7010482194 100644
> --- a/tools/testing/selftests/seccomp/seccomp_bpf.c
> +++ b/tools/testing/selftests/seccomp/seccomp_bpf.c
> @@ -4735,6 +4735,26 @@ TEST(user_notification_wait_killable_fatal)
>  	EXPECT_EQ(SIGTERM, WTERMSIG(status));
>  }
>  
> +TEST(seccomp_filter_load_and_attach)
> +{
> +	struct sock_filter filter[] = {
> +		BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW),
> +	};
> +	struct sock_fprog prog = {
> +		.len = (unsigned short)ARRAY_SIZE(filter),
> +		.filter = filter,
> +	};
> +	int fd, ret;
> +
> +	fd = seccomp(SECCOMP_LOAD_FILTER, 0, &prog);
> +	ASSERT_GT(fd, -1);
> +
> +	ret = seccomp(SECCOMP_ATTACH_FILTER, 0, &fd);
> +	ASSERT_EQ(ret, 0);
> +
> +	close(fd);
> +}

This is a good start -- please check all the error paths as well.

Thanks for continuing to work on this!

-- 
Kees Cook