Count and report non-freed mutexes

Subtract the number of calls to mbedtls_mutex_free() from the number
of calls to mbedtls_mutex_init(). A mutex leak will manifest as a
positive result at the end of the test case.

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
Signed-off-by: Chris Jones <christopher.jones@arm.com>
This commit is contained in:
Gilles Peskine 2021-01-29 22:20:32 +01:00
parent cd2e248fdd
commit 7252ec3947

View File

@ -818,6 +818,17 @@ int mbedtls_test_hexcmp( uint8_t * a, uint8_t * b, uint32_t a_len, uint32_t b_le
* initialized mutex, so attempting to use zero-initialized memory as a mutex
* without calling the init function is detected.
*
* The framework attempts to detect missing calls to init and free by counting
* calls to init and free. If there are more calls to init than free, this
* means that a mutex is not being freed somewhere, which is a memory leak
* on platforms where a mutex consumes resources other than the
* mbedtls_threading_mutex_t object itself. If there are more calls to free
* than init, this indicates a missing init, which is likely to be detected
* by an attempt to lock the mutex as well. A limitation of this framework is
* that it cannot detect scenarios where there is exactly the same number of
* calls to init and free but the calls don't match. A bug like this is
* unlikely happen uniformly throughout the whole test suite though.
*
* If an error is detected, this framework will report what happened and the
* test case will be marked as failed. Unfortunately, the error report cannot
* indicate the exact location of the problematic call. To locate the error,
@ -839,6 +850,13 @@ typedef struct
} mutex_functions_t;
static mutex_functions_t mutex_functions;
/** The total number of calls to mbedtls_mutex_init(), minus the total number
* of calls to mbedtls_mutex_free().
*
* Reset to 0 after each test case.
*/
static int live_mutexes;
static void mbedtls_test_mutex_usage_error( mbedtls_threading_mutex_t *mutex,
const char *msg )
{
@ -855,6 +873,8 @@ static void mbedtls_test_mutex_usage_error( mbedtls_threading_mutex_t *mutex,
static void mbedtls_test_wrap_mutex_init( mbedtls_threading_mutex_t *mutex )
{
mutex_functions.init( mutex );
if( mutex->is_valid )
++live_mutexes;
}
static void mbedtls_test_wrap_mutex_free( mbedtls_threading_mutex_t *mutex )
@ -875,6 +895,8 @@ static void mbedtls_test_wrap_mutex_free( mbedtls_threading_mutex_t *mutex )
mbedtls_test_mutex_usage_error( mutex, "corrupted state" );
break;
}
if( mutex->is_valid )
--live_mutexes;
mutex_functions.free( mutex );
}
@ -936,6 +958,17 @@ static void mbedtls_test_mutex_usage_init( void )
static void mbedtls_test_mutex_usage_check( void )
{
if( live_mutexes != 0 )
{
/* A positive number (more init than free) means that a mutex resource
* is leaking (on platforms where a mutex consumes more than the
* mbedtls_threading_mutex_t object itself). The rare case of a
* negative number means a missing init somewhere. */
mbedtls_fprintf( stdout, "[mutex: %d leaked] ", live_mutexes );
live_mutexes = 0;
if( test_info.mutex_usage_error == NULL )
test_info.mutex_usage_error = "missing free";
}
if( test_info.mutex_usage_error != NULL &&
test_info.result != TEST_RESULT_FAILED )
{