From 89dd2c275e63704d6a02b756e5f2a02d41ed03ef Mon Sep 17 00:00:00 2001
From: Nick Vatamaniuc <vatamane@gmail.com>
Date: Sun, 28 May 2023 01:50:46 -0400
Subject: [PATCH] Fix stack overflow in CVE-2023-31922

isArray and proxy isArray can call each other indefinitely in a mutually
recursive loop.

Add a stack overflow check in the js_proxy_isArray function before calling
JS_isArray(ctx, s->target).

With ASAN the the poc.js from issue 178:

```
./qjs ./poc.js
InternalError: stack overflow
  at isArray (native)
  at <eval> (./poc.js:4)
```

Fix: https://github.com/bellard/quickjs/issues/178
---
 quickjs.c             |  6 ++++++
 tests/test_builtin.js | 20 ++++++++++++++++++++
 2 files changed, 26 insertions(+)

diff --git a/quickjs.c b/quickjs.c
index b64a59ff1..5ed7da09a 100644
--- a/quickjs.c
+++ b/quickjs.c
@@ -43631,6 +43631,12 @@ static int js_proxy_isArray(JSContext *ctx, JSValueConst obj)
     JSProxyData *s = JS_GetOpaque(obj, JS_CLASS_PROXY);
     if (!s)
         return FALSE;
+
+    if (js_check_stack_overflow(ctx->rt, 0)) {
+        JS_ThrowStackOverflow(ctx);
+        return -1;
+    }
+
     if (s->is_revoked) {
         JS_ThrowTypeErrorRevokedProxy(ctx);
         return -1;
diff --git a/tests/test_builtin.js b/tests/test_builtin.js
index 33552d6e3..55cb8e5a1 100644
--- a/tests/test_builtin.js
+++ b/tests/test_builtin.js
@@ -707,6 +707,25 @@ function test_generator()
     assert(v.value === undefined && v.done === true);
 }
 
+/* CVE-2023-31922 */
+function test_proxy_is_array()
+{
+  for (var r = new Proxy ([],{}) , y = 0 ; y < 331072 ; y ++ )
+      r = new Proxy (r, {});
+
+  try {
+    /* Without ASAN */
+    assert(Array.isArray(r));
+  } catch(e) {
+    /* With ASAN expect InternalError "stack overflow" to be raised */
+    if (e instanceof InternalError) {
+      assert(e.message, "stack overflow", "Stack overflow error was not raised")
+    } else {
+      throw(e);
+    }
+  }
+}
+
 test();
 test_function();
 test_enum();
@@ -724,3 +743,4 @@ test_map();
 test_weak_map();
 test_weak_set();
 test_generator();
+test_proxy_is_array();