From 275f247003b2735a6f55289df23a04f31857a985 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Timo=20K=C3=B6ssler?= <info@timokoessler.de>
Date: Mon, 9 Dec 2024 17:04:32 +0100
Subject: [PATCH] Add max depth and array size

---
 library/helpers/attackPath.test.ts | 27 +++++++++++++++++++++++++++
 library/helpers/attackPath.ts      | 25 +++++++++++++++++++------
 2 files changed, 46 insertions(+), 6 deletions(-)

diff --git a/library/helpers/attackPath.test.ts b/library/helpers/attackPath.test.ts
index b4e3ac54..1fbf9eba 100644
--- a/library/helpers/attackPath.test.ts
+++ b/library/helpers/attackPath.test.ts
@@ -60,3 +60,30 @@ t.test("set max count", async (t) => {
 
   t.same(get("test", testArr, 5), [".[0]", ".[1]", ".[2]", ".[3]", ".[4]"]);
 });
+
+t.test("respects max depth and array length", async (t) => {
+  const generateTestObjectWithDepth = (depth: number): object | string => {
+    if (depth === 0) {
+      return "testValue";
+    }
+
+    const obj = {
+      prop: generateTestObjectWithDepth(depth - 1),
+    };
+
+    return obj;
+  };
+
+  t.same(get("testValue", generateTestObjectWithDepth(100)), []);
+  t.same(get("testValue", generateTestObjectWithDepth(31)), []);
+  t.same(get("testValue", generateTestObjectWithDepth(30)), [
+    ".prop".repeat(30),
+  ]);
+
+  const testArr = Array.from({ length: 101 }, (_, i) => i.toString());
+
+  t.same(get("50", testArr), [".[50]"]);
+  t.same(get("99", testArr), [".[99]"]);
+  t.same(get("100", testArr), [".[100]"]);
+  t.same(get("101", testArr), []);
+});
diff --git a/library/helpers/attackPath.ts b/library/helpers/attackPath.ts
index 03214dcc..8107e013 100644
--- a/library/helpers/attackPath.ts
+++ b/library/helpers/attackPath.ts
@@ -4,6 +4,12 @@ import { tryDecodeAsJWT } from "./tryDecodeAsJWT";
 // Default match count to return
 const DEFAULT_MATCH_COUNT = 1;
 
+// Maximum depth to traverse
+const MAX_DEPTH = 30;
+
+// Maximum array length to traverse
+const MAX_ARRAY_LENGTH = 100;
+
 export type PathPart =
   | { type: "jwt" }
   | { type: "object"; key: string }
@@ -40,11 +46,15 @@ export function getPathsToPayload(
 
   const attackPayloadLowercase = attackPayload.toLowerCase();
 
-  const traverse = (value: unknown, path: PathPart[] = []) => {
+  const traverse = (value: unknown, path: PathPart[] = [], depth = 0) => {
     if (matches.length >= matchCount) {
       return;
     }
 
+    if (depth > MAX_DEPTH) {
+      return;
+    }
+
     // Handle strings
     if (typeof value === "string") {
       if (value.toLowerCase() === attackPayloadLowercase) {
@@ -54,7 +64,7 @@ export function getPathsToPayload(
 
       const jwt = tryDecodeAsJWT(value);
       if (jwt.jwt) {
-        traverse(jwt.object, path.concat({ type: "jwt" }));
+        traverse(jwt.object, path.concat({ type: "jwt" }), depth + 1);
       }
 
       return;
@@ -62,9 +72,12 @@ export function getPathsToPayload(
 
     if (Array.isArray(value)) {
       // Handle arrays
-      value.forEach((item, index) => {
-        traverse(item, path.concat({ type: "array", index }));
-      });
+      for (const [index, item] of value.entries()) {
+        if (index > MAX_ARRAY_LENGTH) {
+          break;
+        }
+        traverse(item, path.concat({ type: "array", index }), depth + 1);
+      }
 
       if (value.join().toLowerCase() === attackPayloadLowercase) {
         matches.push(buildPathToPayload(path));
@@ -76,7 +89,7 @@ export function getPathsToPayload(
     if (isPlainObject(value)) {
       // Handle objects
       for (const key in value) {
-        traverse(value[key], path.concat({ type: "object", key }));
+        traverse(value[key], path.concat({ type: "object", key }), depth + 1);
       }
     }
   };