From 083c5f08ec4e95c9b75810d46f933928327a5ab3 Mon Sep 17 00:00:00 2001
From: Nobuyoshi Nakada <nobu@ruby-lang.org>
Date: Thu, 10 Dec 2020 22:00:11 +0900
Subject: [PATCH] Check stack overflow in recursive glob_helper [Bug #17162]

---
 dir.c         |  2 ++
 internal/vm.h |  1 +
 vm_eval.c     | 10 ++++++++++
 3 files changed, 13 insertions(+)

diff --git a/dir.c b/dir.c
index 48c9eaefa0..fc2c811509 100644
--- a/dir.c
+++ b/dir.c
@@ -2274,6 +2274,8 @@ glob_helper(
     int escape = !(flags & FNM_NOESCAPE);
     size_t pathlen = baselen + namelen;
 
+    rb_check_stack_overflow();
+
     for (cur = beg; cur < end; ++cur) {
 	struct glob_pattern *p = *cur;
 	if (p->type == RECURSIVE) {
diff --git a/internal/vm.h b/internal/vm.h
index a0e067d40c..80f2c792a3 100644
--- a/internal/vm.h
+++ b/internal/vm.h
@@ -80,6 +80,7 @@ VALUE rb_yield_force_blockarg(VALUE values);
 VALUE rb_lambda_call(VALUE obj, ID mid, int argc, const VALUE *argv,
                      rb_block_call_func_t bl_proc, int min_argc, int max_argc,
                      VALUE data2);
+void rb_check_stack_overflow(void);
 
 /* vm_insnhelper.c */
 VALUE rb_equal_opt(VALUE obj1, VALUE obj2);
diff --git a/vm_eval.c b/vm_eval.c
index f9e7356c30..8eb1d5c84c 100644
--- a/vm_eval.c
+++ b/vm_eval.c
@@ -302,6 +302,16 @@ stack_check(rb_execution_context_t *ec)
 
 #ifndef MJIT_HEADER
 
+void
+rb_check_stack_overflow(void)
+{
+#ifndef RB_THREAD_LOCAL_SPECIFIER
+    if (!ruby_current_ec_key) return;
+#endif
+    rb_execution_context_t *ec = GET_EC();
+    if (ec) stack_check(ec);
+}
+
 static inline const rb_callable_method_entry_t *rb_search_method_entry(VALUE recv, ID mid);
 static inline enum method_missing_reason rb_method_call_status(rb_execution_context_t *ec, const rb_callable_method_entry_t *me, call_type scope, VALUE self);