Fix use-after-free when destroying selection sources

include/wlr/types/wlr_data_device.h

@@ -126,4 +126,6 @@ void wlr_seat_set_selection(struct wlr_seat *seat,
 
 void wlr_data_source_init(struct wlr_data_source *source);
 
+void wlr_data_source_finish(struct wlr_data_source *source);
+
 #endif

include/wlr/types/wlr_primary_selection.h

@@ -52,5 +52,7 @@ void wlr_seat_set_primary_selection(struct wlr_seat *seat,
 
 void wlr_primary_selection_source_init(
 	struct wlr_primary_selection_source *source);
+void wlr_primary_selection_source_finish(
+	struct wlr_primary_selection_source *source);
 
 #endif

types/wlr_data_device.c

@@ -856,16 +856,7 @@ void data_device_manager_get_data_device(struct wl_client *client,
 static void data_source_resource_destroy(struct wl_resource *resource) {
 	struct wlr_data_source *source =
 		wl_resource_get_user_data(resource);
-	char **p;
-
-	wl_signal_emit(&source->events.destroy, source);
-
-	wl_array_for_each(p, &source->mime_types) {
-		free(*p);
-	}
-
-	wl_array_release(&source->mime_types);
-
+	wlr_data_source_finish(source);
 	free(source);
 }
 
@@ -932,6 +923,20 @@ void wlr_data_source_init(struct wlr_data_source *source) {
 	wl_signal_init(&source->events.destroy);
 }
 
+void wlr_data_source_finish(struct wlr_data_source *source) {
+	if (source == NULL) {
+		return;
+	}
+
+	wl_signal_emit(&source->events.destroy, source);
+
+	char **p;
+	wl_array_for_each(p, &source->mime_types) {
+		free(*p);
+	}
+	wl_array_release(&source->mime_types);
+}
+
 static void data_device_manager_create_data_source(struct wl_client *client,
 		struct wl_resource *resource, uint32_t id) {
 	struct wlr_data_source *source = calloc(1, sizeof(struct wlr_data_source));

types/wlr_primary_selection.c

@@ -144,15 +144,7 @@ static const struct gtk_primary_selection_source_interface source_impl = {
 static void source_resource_handle_destroy(struct wl_resource *resource) {
 	struct wlr_primary_selection_source *source =
 		wl_resource_get_user_data(resource);
-
-	wl_signal_emit(&source->events.destroy, source);
-
-	char **p;
-	wl_array_for_each(p, &source->mime_types) {
-		free(*p);
-	}
-	wl_array_release(&source->mime_types);
-
+	wlr_primary_selection_source_finish(source);
 	free(source);
 }
 
@@ -268,6 +260,21 @@ void wlr_primary_selection_source_init(
 	wl_signal_init(&source->events.destroy);
 }
 
+void wlr_primary_selection_source_finish(
+		struct wlr_primary_selection_source *source) {
+	if (source == NULL) {
+		return;
+	}
+
+	wl_signal_emit(&source->events.destroy, source);
+
+	char **p;
+	wl_array_for_each(p, &source->mime_types) {
+		free(*p);
+	}
+	wl_array_release(&source->mime_types);
+}
+
 static void device_manager_handle_create_source(struct wl_client *client,
 		struct wl_resource *manager_resource, uint32_t id) {
 	struct wlr_primary_selection_source *source =

xwayland/selection.c

@@ -508,6 +508,7 @@ static void data_source_send(struct wlr_data_source *base,
 
 static void data_source_cancel(struct wlr_data_source *base) {
 	struct x11_data_source *source = (struct x11_data_source *)base;
+	wlr_data_source_finish(&source->base);
 	wl_array_release(&source->mime_types_atoms);
 	free(source);
 }
@@ -533,6 +534,7 @@ static void primary_selection_source_cancel(
 		struct wlr_primary_selection_source *base) {
 	struct x11_primary_selection_source *source =
 		(struct x11_primary_selection_source *)base;
+	wlr_primary_selection_source_finish(&source->base);
 	wl_array_release(&source->mime_types_atoms);
 	free(source);
 }