pbx.c: On error, ast_add_extension2_lockopt should always free 'data'

In the event that the desired extension already exists,
ast_add_extension2_lockopt() will free the 'data' it is passed before
returning an error, so we should not be freeing it ourselves.

Additionally, there were two places where ast_add_extension2_lockopt()
could return an error without also freeing the 'data' pointer, so we
add that.

ASTERISK-29097 #close

Change-Id: I904707aae55169feda050a5ed7c6793b53fe6eae

include/asterisk/pbx.h

@@ -492,9 +492,13 @@ void ast_pbx_hangup_handler_push(struct ast_channel *chan, const char *handler);
  * \param callerid pattern to match CallerID, or NULL to match any CallerID
  * \param application application to run on the extension with that priority level
  * \param data data to pass to the application
- * \param datad
+ * \param datad a pointer to a function that will deallocate \c data when needed
+ *              or NULL if \c data does not need to be freed.
  * \param registrar who registered the extension
  *
+ * \note On any failure, the function pointed to by \c datap will be called and passed the
+ *       \c data pointer.
+ *
  * \retval 0 success
  * \retval -1 failure
  */
@@ -520,7 +524,7 @@ int ast_add_extension2(struct ast_context *con, int replace, const char *extensi
  * \since 12.0.0
  *
  * \note con must be write locked prior to calling. For details about the arguments,
- *       check ast_add_extension2()
+ *       check ast_add_extension()
  */
 int ast_add_extension2_nolock(struct ast_context *con, int replace, const char *extension,
 	int priority, const char *label, const char *callerid,

main/pbx.c

@@ -7346,6 +7346,10 @@ static int ast_add_extension2_lockopt(struct ast_context *con,
 	if (ast_strlen_zero(extension)) {
 		ast_log(LOG_ERROR,"You have to be kidding-- add exten '' to context %s? Figure out a name and call me back. Action ignored.\n",
 				con->name);
+		/* We always need to deallocate 'data' on failure */
+		if (datad) {
+			datad(data);
+		}
 		return -1;
 	}
 
@@ -7401,8 +7405,14 @@ static int ast_add_extension2_lockopt(struct ast_context *con,
 	}
 
 	/* Be optimistic:  Build the extension structure first */
-	if (!(tmp = ast_calloc(1, length)))
+	tmp = ast_calloc(1, length);
+	if (!tmp) {
+		/* We always need to deallocate 'data' on failure */
+		if (datad) {
+			datad(data);
+		}
 		return -1;
+	}
 
 	if (ast_strlen_zero(label)) /* let's turn empty labels to a null ptr */
 		label = 0;

res/parking/parking_bridge_features.c

@@ -661,7 +661,6 @@ static int parking_duration_callback(struct ast_bridge_channel *bridge_channel,
 			dial_string_flat, PARK_DIAL_CONTEXT, ast_get_extension_registrar(existing_exten));
 	} else if (ast_add_extension2_nolock(park_dial_context, 1, dial_string_flat, 1, NULL, NULL,
 			"Dial", duplicate_returnexten, ast_free_ptr, BASE_REGISTRAR, NULL, 0)) {
-			ast_free(duplicate_returnexten);
 		ast_log(LOG_ERROR, "Failed to create parking redial parker extension %s@%s - Dial(%s)\n",
 			dial_string_flat, PARK_DIAL_CONTEXT, returnexten);
 	}

res/res_parking.c

@@ -724,7 +724,6 @@ static int parking_add_extension(struct ast_context *context, int replace, const
 
 	if (ast_add_extension2_nolock(context, replace, extension, priority, NULL, NULL,
 			application, data_duplicate, ast_free_ptr, registrar, NULL, 0)) {
-		ast_free(data_duplicate);
 		return -1;
 	}
 

res/res_pjsip_config_wizard.c

@@ -475,7 +475,6 @@ static int add_extension(struct ast_context *context, const char *exten,
 
 	if (ast_add_extension2_nolock(context, 0, exten, priority, NULL, NULL,
 			app, data, free_ptr, BASE_REGISTRAR, NULL, 0)) {
-		ast_free(data);
 		return -1;
 	}