Re: [PATCH 2/4] seccomp: add two missing ptrace ifdefines

Tyler Hicks
2019-09-18T09:15:22Z

On 2019-09-18 10:48:31, Christian Brauner wrote:
> Add tw missing ptrace ifdefines to avoid compilation errors on systems
> that do not provide PTRACE_EVENTMSG_SYSCALL_ENTRY or
> PTRACE_EVENTMSG_SYSCALL_EXIT or:
>
> gcc -Wl,-no-as-needed -Wall seccomp_bpf.c -lpthread -o seccomp_bpf
> In file included from seccomp_bpf.c:52:0:
> seccomp_bpf.c: In function ‘tracer_ptrace’:
> seccomp_bpf.c:1792:20: error: ‘PTRACE_EVENTMSG_SYSCALL_ENTRY’ undeclared (first use in this function); did you mean ‘PTRACE_EVENT_CLONE’?
> EXPECT_EQ(entry ? PTRACE_EVENTMSG_SYSCALL_ENTRY
> ^
> ../kselftest_harness.h:608:13: note: in definition of macro ‘__EXPECT’
> __typeof__(_expected) __exp = (_expected); \
> ^~~~~~~~~
> seccomp_bpf.c:1792:2: note: in expansion of macro ‘EXPECT_EQ’
> EXPECT_EQ(entry ? PTRACE_EVENTMSG_SYSCALL_ENTRY
> ^~~~~~~~~
> seccomp_bpf.c:1792:20: note: each undeclared identifier is reported only once for each function it appears in
> EXPECT_EQ(entry ? PTRACE_EVENTMSG_SYSCALL_ENTRY
> ^
> ../kselftest_harness.h:608:13: note: in definition of macro ‘__EXPECT’
> __typeof__(_expected) __exp = (_expected); \
> ^~~~~~~~~
> seccomp_bpf.c:1792:2: note: in expansion of macro ‘EXPECT_EQ’
> EXPECT_EQ(entry ? PTRACE_EVENTMSG_SYSCALL_ENTRY
> ^~~~~~~~~
> seccomp_bpf.c:1793:6: error: ‘PTRACE_EVENTMSG_SYSCALL_EXIT’ undeclared (first use in this function); did you mean ‘PTRACE_EVENTMSG_SYSCALL_ENTRY’?
> : PTRACE_EVENTMSG_SYSCALL_EXIT, msg);
> ^
> ../kselftest_harness.h:608:13: note: in definition of macro ‘__EXPECT’
> __typeof__(_expected) __exp = (_expected); \
> ^~~~~~~~~
> seccomp_bpf.c:1792:2: note: in expansion of macro ‘EXPECT_EQ’
> EXPECT_EQ(entry ? PTRACE_EVENTMSG_SYSCALL_ENTRY
> ^~~~~~~~~
>
> Fixes: 6a21cc50f0c7 ("seccomp: add a return code to trap to userspace")

I think this Fixes line is incorrect and should be changed to:

Fixes: 201766a20e30 ("ptrace: add PTRACE_GET_SYSCALL_INFO request")

With that changed,

Reviewed-by: Tyler Hicks <tyhicks@canonical.com>

Tyler

> Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
> Cc: Kees Cook <keescook@chromium.org>
> Cc: Andy Lutomirski <luto@amacapital.net>
> Cc: Will Drewry <wad@chromium.org>
> Cc: Shuah Khan <shuah@kernel.org>
> Cc: Alexei Starovoitov <ast@kernel.org>
> Cc: Daniel Borkmann <daniel@iogearbox.net>
> Cc: Martin KaFai Lau <kafai@fb.com>
> Cc: Song Liu <songliubraving@fb.com>
> Cc: Yonghong Song <yhs@fb.com>
> Cc: Tycho Andersen <tycho@tycho.ws>
> CC: Tyler Hicks <tyhicks@canonical.com>
> Cc: Jann Horn <jannh@google.com>
> Cc: stable@vger.kernel.org
> Cc: linux-kselftest@vger.kernel.org
> Cc: netdev@vger.kernel.org
> Cc: bpf@vger.kernel.org
> ---
> tools/testing/selftests/seccomp/seccomp_bpf.c | 8 ++++++++
> 1 file changed, 8 insertions(+)
>
> diff --git a/tools/testing/selftests/seccomp/seccomp_bpf.c b/tools/testing/selftests/seccomp/seccomp_bpf.c
> index 6ef7f16c4cf5..ee52eab01800 100644
> --- a/tools/testing/selftests/seccomp/seccomp_bpf.c
> +++ b/tools/testing/selftests/seccomp/seccomp_bpf.c
> @@ -155,6 +155,14 @@ struct seccomp_data {
> #ifndef PTRACE_SECCOMP_GET_METADATA
> #define PTRACE_SECCOMP_GET_METADATA 0x420d
>
> +#ifndef PTRACE_EVENTMSG_SYSCALL_ENTRY
> +#define PTRACE_EVENTMSG_SYSCALL_ENTRY 1
> +#endif
> +
> +#ifndef PTRACE_EVENTMSG_SYSCALL_EXIT
> +#define PTRACE_EVENTMSG_SYSCALL_EXIT 2
> +#endif
> +
> struct seccomp_metadata {
> __u64 filter_off; /* Input: which filter */
> __u64 flags; /* Output: filter's flags */
> --
> 2.23.0
>