Add safety check to sample mutex implementation
Due to inconsistent freeing strategy in pkparse.c the sample mutex
implementation in threading.c could lead to undefined behaviour by
destroying the same mutex several times.
This fix prevents mutexes from being destroyed several times in the
sample threading implementation.
diff --git a/ChangeLog b/ChangeLog
index ec395e5..c6addbe 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -15,6 +15,8 @@
* Fixed the sample applications gen_key.c, cert_req.c and cert_write.c for
builds where the configuration MBEDTLS_PEM_WRITE_C is not defined. Found
by inestlerode. #559.
+ * Fixed default threading implementation to avoid accidental double
+ initialisations and double frees.
= mbed TLS 2.1.5 branch released 2016-06-28
diff --git a/library/threading.c b/library/threading.c
index 1b6d9cd..83ec01a 100644
--- a/library/threading.c
+++ b/library/threading.c
@@ -32,7 +32,7 @@
#if defined(MBEDTLS_THREADING_PTHREAD)
static void threading_mutex_init_pthread( mbedtls_threading_mutex_t *mutex )
{
- if( mutex == NULL )
+ if( mutex == NULL || mutex->is_valid )
return;
mutex->is_valid = pthread_mutex_init( &mutex->mutex, NULL ) == 0;
@@ -40,10 +40,11 @@
static void threading_mutex_free_pthread( mbedtls_threading_mutex_t *mutex )
{
- if( mutex == NULL )
+ if( mutex == NULL || !mutex->is_valid )
return;
(void) pthread_mutex_destroy( &mutex->mutex );
+ mutex->is_valid = 0;
}
static int threading_mutex_lock_pthread( mbedtls_threading_mutex_t *mutex )