Fix 0 size allocation

src/collections/slice.c

@@ -38,6 +38,7 @@ void _z_delete_context_delete(_z_delete_context_t *c, void *data) {
 
 /*-------- Slice --------*/
 z_result_t _z_slice_init(_z_slice_t *bs, size_t capacity) {
+    assert(capacity != 0);
     bs->start = (uint8_t *)z_malloc(capacity);
     if (bs->start == NULL) {
         bs->len = 0;

src/protocol/definitions/transport.c

@@ -341,7 +341,9 @@ void _z_t_msg_copy_init(_z_t_msg_init_t *clone, _z_t_msg_init_t *msg) {
 void _z_t_msg_copy_open(_z_t_msg_open_t *clone, _z_t_msg_open_t *msg) {
     clone->_lease = msg->_lease;
     clone->_initial_sn = msg->_initial_sn;
-    _z_slice_copy(&clone->_cookie, &msg->_cookie);
+    if (!_z_slice_is_empty(&msg->_cookie)) {
+        _z_slice_copy(&clone->_cookie, &msg->_cookie);
+    }
 }
 
 void _z_t_msg_copy_close(_z_t_msg_close_t *clone, _z_t_msg_close_t *msg) { clone->_reason = msg->_reason; }

src/system/freertos_plus_tcp/system.c

@@ -49,7 +49,12 @@ void z_random_fill(void *buf, size_t len) {
 }
 
 /*------------------ Memory ------------------*/
-void *z_malloc(size_t size) { return pvPortMalloc(size); }
+void *z_malloc(size_t size) {
+    if (size == 0) {
+        return NULL;
+    }
+    return pvPortMalloc(size);
+}
 
 void *z_realloc(void *ptr, size_t size) {
     _ZP_UNUSED(ptr);

src/system/rpi_pico/system.c

@@ -41,7 +41,12 @@ void z_random_fill(void *buf, size_t len) {
 }
 
 /*------------------ Memory ------------------*/
-void *z_malloc(size_t size) { return pvPortMalloc(size); }
+void *z_malloc(size_t size) {
+    if (size == 0) {
+        return NULL;
+    }
+    return pvPortMalloc(size);
+}
 
 void *z_realloc(void *ptr, size_t size) {
     _ZP_UNUSED(ptr);

src/transport/unicast/transport.c

@@ -151,7 +151,7 @@ static z_result_t _z_unicast_handshake_client(_z_transport_unicast_establish_par
         return ret;
     }
     // Try to receive response
-    _z_transport_message_t iam;
+    _z_transport_message_t iam = {0};
     _Z_RETURN_IF_ERR(_z_link_recv_t_msg(&iam, zl));
     if ((_Z_MID(iam._header) != _Z_MID_T_INIT) || !_Z_HAS_FLAG(iam._header, _Z_FLAG_T_INIT_A)) {
         _z_t_msg_clear(&iam);
@@ -213,7 +213,7 @@ static z_result_t _z_unicast_handshake_client(_z_transport_unicast_establish_par
         return ret;
     }
     // Try to receive response
-    _z_transport_message_t oam;
+    _z_transport_message_t oam = {0};
     _Z_RETURN_IF_ERR(_z_link_recv_t_msg(&oam, zl));
     if ((_Z_MID(oam._header) != _Z_MID_T_OPEN) || !_Z_HAS_FLAG(oam._header, _Z_FLAG_T_OPEN_A)) {
         _z_t_msg_clear(&oam);
@@ -234,7 +234,7 @@ static z_result_t _z_unicast_handshake_client(_z_transport_unicast_establish_par
 static z_result_t _z_unicast_handshake_listener(_z_transport_unicast_establish_param_t *param, const _z_link_t *zl,
                                                 const _z_id_t *local_zid, enum z_whatami_t whatami) {
     // Read t message from link
-    _z_transport_message_t tmsg;
+    _z_transport_message_t tmsg = {0};
     z_result_t ret = _z_link_recv_t_msg(&tmsg, zl);
     if (ret != _Z_RES_OK) {
         return ret;