From 0be2b01a6b0ff15091318dc87fc153c20a58bbce Mon Sep 17 00:00:00 2001 From: Janos Follath Date: Mon, 26 Sep 2016 09:15:44 +0100 Subject: [PATCH] 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. --- ChangeLog | 2 ++ library/threading.c | 5 +++-- 2 files changed, 5 insertions(+), 2 deletions(-) diff --git a/ChangeLog b/ChangeLog index f3e60d3f5..a10559f8b 100644 --- a/ChangeLog +++ b/ChangeLog @@ -29,6 +29,8 @@ Bugfix a contribution from Tobias Tangemann. #541 * Fixed cert_app sample program for debug output and for use when no root certificates are provided. + * Fixed default threading implementation to avoid accidental double + initialisations and double frees. * Fix mbedtls_x509_get_sig() to update the ASN1 type in the mbedtls_x509_buf data structure until after error checks are successful. Found by subramanyam-c. diff --git a/library/threading.c b/library/threading.c index 1b6d9cd44..83ec01a45 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_init_pthread( mbedtls_threading_mutex_t *mutex ) 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 )