On Wed, Apr 19, 2017 at 2:51 PM, Micka?l Sala?n [off-list ref] wrote:

On 19/04/2017 02:02, Kees Cook wrote:

quoted

On Tue, Mar 28, 2017 at 4:46 PM, Micka?l Sala?n [off-list ref] wrote:

quoted

This is useful to return an information about the error without being
able to write to TH_LOG_STREAM.

Helpers from test_harness.h may be useful outside of the seccomp
directory.

Signed-off-by: Micka?l Sala?n <mic@digikod.net>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Kees Cook <redacted>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Will Drewry <wad@chromium.org>
---
 tools/testing/selftests/seccomp/test_harness.h | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/seccomp/test_harness.h b/tools/testing/selftests/seccomp/test_harness.h
index a786c69c7584..77e407663e06 100644
--- a/tools/testing/selftests/seccomp/test_harness.h
+++ b/tools/testing/selftests/seccomp/test_harness.h

@@ -397,7 +397,7 @@ struct __test_metadata {
        const char *name;
        void (*fn)(struct __test_metadata *);
        int termsig;
-       int passed;
+       __s8 passed;

Why the reduction here? int is signed too?

Because the return code of a process is capped to 8 bits and I use a
negative value to not mess with the current interpretation of 0 (error)
and 1 (OK) for the "passed" variable.

quoted

quoted

        int trigger; /* extra handler after the evaluation */
        struct __test_metadata *prev, *next;
 };

@@ -476,6 +476,12 @@ void __run_test(struct __test_metadata *t)
                                        "instead of by signal (code: %d)\n",
                                        t->name,
                                        WEXITSTATUS(status));
+                       } else if (t->passed < 0) {
+                               fprintf(TH_LOG_STREAM,
+                                       "%s: Failed at step #%d\n",
+                                       t->name,
+                                       t->passed * -1);
+                               t->passed = 0;
                        }

Instead of creating an overloaded mechanism here, perhaps have an
option reporting mechanism that can be enabled. Like adding to
__test_metadata "bool no_stream; int test_number;" and adding
test_number++ to each ASSERT/EXCEPT call, and doing something like:

if (t->no_stream) {
                              fprintf(TH_LOG_STREAM,
                                      "%s: Failed at step #%d\n",
                                      t->name,
                                       t->test_number);
}

It'd be a cleaner approach, maybe?

Good idea, we will then be able to use 255 steps!

Do you want me to send this as a separate patch?

Can we move test_harness.h outside of the seccomp directory to be
available to other subsystems as well?

Yeah, I would do two patches, and send them out separately (to shuah
with lkml and me in cc at least), one to move test_hardness.h into
some include/ directory, and then to add the new logic for streamless
reporting.

Thanks!

-Kees


-- 
Kees Cook
Pixel Security
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