ast: fix scope double free in ut_free()

Zero the scope object pointer in the scope structure before putting the
JSON object in order to avoid a double-free by the scope's userdata
destructor function.

Signed-off-by: Jo-Philipp Wich <jo@mein.io>

1 files changed, 3 insertions, 1 deletions

diff --git a/ast.c b/ast.c
index 2e1c169..126676a 100644
--- a/ast.c
+++ b/ast.c
@@ -525,6 +525,7 @@ ut_free(struct ut_state *s)
 {
 	struct ut_source *src, *src_next;
 	struct ut_scope *sc, *sc_next;
+	struct json_object *scj;
 	size_t n;
 
 	if (s) {
@@ -547,8 +548,9 @@ ut_free(struct ut_state *s)
 	json_object_put(s->rval);
 
 	for (sc = s->scopelist; sc; sc = sc->next) {
-		json_object_put(sc->scope);
+		scj = sc->scope;
 		sc->scope = NULL;
+		json_object_put(scj);
 	}
 
 	for (sc = s->scopelist; sc; sc = sc_next) {