From 11679e3f3a5e7680895e19f5cbc7b306be6c9d45 Mon Sep 17 00:00:00 2001
From: "Yukihiro \"Matz\" Matsumoto" <matz@ruby.or.jp>
Date: Fri, 22 Apr 2022 08:32:18 +0900
Subject: [PATCH] vm.c: check if target_class is NULL (when prepended).

Address CVE-2022-1427
---
 src/vm.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/src/vm.c b/src/vm.c
index 8a79b950c..3501abf57 100644
--- a/src/vm.c
+++ b/src/vm.c
@@ -1753,10 +1753,7 @@ RETRY_TRY_BLOCK:
         mrb_exc_set(mrb, exc);
         goto L_RAISE;
       }
-      if (target_class->flags & MRB_FL_CLASS_IS_PREPENDED) {
-        target_class = mrb_vm_ci_target_class(ci);
-      }
-      else if (target_class->tt == MRB_TT_MODULE) {
+      if ((target_class->flags & MRB_FL_CLASS_IS_PREPENDED) || target_class->tt == MRB_TT_MODULE) {
         target_class = mrb_vm_ci_target_class(ci);
         if (!target_class || target_class->tt != MRB_TT_ICLASS) {
           goto super_typeerror;