[lttng-dev] [PATCH lttng-tools] Fix: test_ust_data dereference of null pointer

[Jérémie Galarneau]

On 17 January 2017 at 10:08, Jonathan Rajotte
<jonathan.rajotte-julien at efficios.com> wrote:
> Skip test on NULL value to prevent null dereference.
>
> Signed-off-by: Jonathan Rajotte <jonathan.rajotte-julien at efficios.com>
> ---
>  tests/unit/test_ust_data.c | 36 +++++++++++++++++++++++++++++++-----
>  1 file changed, 31 insertions(+), 5 deletions(-)
>
> diff --git a/tests/unit/test_ust_data.c b/tests/unit/test_ust_data.c
> index 82d15b6..2a04da5 100644
> --- a/tests/unit/test_ust_data.c
> +++ b/tests/unit/test_ust_data.c
> @@ -84,6 +84,11 @@ static void test_create_one_ust_session(void)
>         usess = trace_ust_create_session(42);
>         ok(usess != NULL, "Create UST session");
>
> +       if (!usess) {
> +               skip(1, "UST session is null");
> +               return;
> +       }
> +
>         ok(usess->id == 42 &&
>            usess->active == 0 &&
>            usess->domain_global.channels != NULL &&
> @@ -106,6 +111,11 @@ static void test_create_ust_channel(void)
>         uchan = trace_ust_create_channel(&attr, LTTNG_DOMAIN_UST);
>         ok(uchan != NULL, "Create UST channel");
>
> +       if (!usess) {
> +               skip(1, "UST session is null");
> +               return;
> +       }
> +
>         ok(uchan->enabled == 0 &&
>            strncmp(uchan->name, "channel0", 8) == 0 &&
>            uchan->name[LTTNG_UST_SYM_NAME_LEN - 1] == '\0' &&
> @@ -133,6 +143,11 @@ static void test_create_ust_event(void)
>
>         ok(event != NULL, "Create UST event");
>
> +       if (!event) {
> +               skip(1, "UST event is null");
> +               return;
> +       }
> +
>         ok(event->enabled == 0 &&
>            event->attr.instrumentation == LTTNG_UST_TRACEPOINT &&
>            strcmp(event->attr.name, ev.name) == 0 &&
> @@ -167,8 +182,8 @@ static void test_create_ust_event_exclusion(void)
>                 LTTNG_SYMBOL_NAME_LEN * exclusion_count);
>         ok(exclusion != NULL, "Create UST exclusion");
>         if (!exclusion) {
> -               PERROR("zmalloc");
> -               abort();
> +               skip(4, "zmalloc failed");
> +               goto end;
>         }
>
>         exclusion->count = exclusion_count;
> @@ -187,8 +202,8 @@ static void test_create_ust_event_exclusion(void)
>                 LTTNG_SYMBOL_NAME_LEN * exclusion_count);
>         ok(exclusion != NULL, "Create UST exclusion");
>         if (!exclusion) {
> -               PERROR("zmalloc");
> -               abort();
> +               skip(2, "zmalloc failed");
> +               goto end;
>         }
>
>         exclusion->count = exclusion_count;
> @@ -198,10 +213,14 @@ static void test_create_ust_event_exclusion(void)
>                 get_random_string(), LTTNG_SYMBOL_NAME_LEN);
>
>         event = trace_ust_create_event(&ev, NULL, NULL, exclusion, false);
> -       assert(event != NULL);
>
>         ok(event != NULL, "Create UST event with different exclusion names");
>
> +       if (!event) {
> +               skip(1, "UST event with exclusion is null");
> +               goto error_event;

This will result in a double-free since trace_ust_create_event()
already frees exclusion on failure.

Fixed in the merged version.

Thanks!
Jérémie

> +       }
> +
>         ok(event->enabled == 0 &&
>            event->attr.instrumentation == LTTNG_UST_TRACEPOINT &&
>            strcmp(event->attr.name, ev.name) == 0 &&
> @@ -213,6 +232,13 @@ static void test_create_ust_event_exclusion(void)
>            "Validate UST event and exclusion");
>
>         trace_ust_destroy_event(event);
> +
> +       return;
> +
> +error_event:
> +       free(exclusion);
> +end:
> +       return;
>  }
>
>
> --
> 2.7.4
>



-- 
Jérémie Galarneau
EfficiOS Inc.
http://www.efficios.com