LibJS: Prevent stack overflow if Proxy handler's __proto__ is the Proxy

Fixes #9322.
Author: https://github.com/linusg Commit: 941ff0cf60 Pull-request: https://github.com/SerenityOS/serenity/pull/9842 Reviewed-by: https://github.com/IdanHo ✅
2025-08-11 02:29:21 +00:00 · 2021-09-05 20:21:58 +01:00 · 2021-09-05 20:21:58 +01:00 · 941ff0cf60 · 2024-07-18 04:39:55 +09:00
commit 941ff0cf60
parent 9998a2c91e
2 changed files with 27 additions and 0 deletions
--- a/Userland/Libraries/LibJS/Tests/builtins/Proxy/Proxy.handler-get.js
+++ b/Userland/Libraries/LibJS/Tests/builtins/Proxy/Proxy.handler-get.js
@ -107,3 +107,12 @@ describe("[[Get]] invariants", () => {
        );
    });
 });
+
+test("Proxy handler that has the Proxy itself as its prototype", () => {
+    const handler = {};
+    const proxy = new Proxy({}, handler);
+    handler.__proto__ = proxy;
+    expect(() => {
+        proxy.foo;
+    }).toThrowWithMessage(Error, "Call stack size limit exceeded");
+});