From f02760fc0a455f376ad1a855fd1a5e9252c8267c Mon Sep 17 00:00:00 2001 From: "Urabe, Shyouhei" Date: Wed, 24 Apr 2019 15:30:25 +0900 Subject: [PATCH] avoid reading uninitialized variable autoload_reset() can read this state.result. Because autoload_reset is a function passed to rb_ensure, there is a chance when an execption raises before actually filling this memory region. test/ruby/test_defined.rb:test_autoload_noload is one of such case. Found using memory sanitizer. ==54014==WARNING: MemorySanitizer: use-of-uninitialized-value #0 0x557a683f3e5a in autoload_reset variable.c:2372:9 #1 0x557a6707a93b in rb_ensure eval.c:1084:5 #2 0x557a683efbf5 in rb_autoload_load variable.c:2475:14 #3 0x557a685fc460 in vm_get_ev_const vm_insnhelper.c:938:4 #4 0x557a68448e0a in vm_exec_core insns.def:267:11 --- variable.c | 1 + 1 file changed, 1 insertion(+) diff --git a/variable.c b/variable.c index 2c69e2169c..cb24076dd0 100644 --- a/variable.c +++ b/variable.c @@ -2472,6 +2472,7 @@ rb_autoload_load(VALUE mod, ID id) } /* autoload_data_i can be deleted by another thread while require */ + state.result = Qfalse; result = rb_ensure(autoload_require, (VALUE)&state, autoload_reset, (VALUE)&state);