From 926a3b6ea8f3bc0d71f294adc78d4bbd545c20ab Mon Sep 17 00:00:00 2001
From: Weirdo <git.jonas@kamsker.at>
Date: Mon, 29 Mar 2021 01:12:30 +0200
Subject: [PATCH] Added client side redundant response validation

---
 src/ChecksumResolver.js       | 22 ++++++++++++++----
 src/Utils/AaxHashAlgorithm.js | 44 +++++++++++++++++++++++++++++++++++
 2 files changed, 62 insertions(+), 4 deletions(-)
 create mode 100644 src/Utils/AaxHashAlgorithm.js

diff --git a/src/ChecksumResolver.js b/src/ChecksumResolver.js
index 2493b2c..c4f3cb9 100644
--- a/src/ChecksumResolver.js
+++ b/src/ChecksumResolver.js
@@ -32,6 +32,8 @@ import ReactNotification from 'react-notifications-component'
 import { store } from 'react-notifications-component';
 // import 'animate.css/animate.compat.css'
 
+import AaxHashAlgorithm from './Utils/AaxHashAlgorithm'
+
 
 const useStyles = theme => ({
     paper: {
@@ -137,12 +139,24 @@ class ChecksumResolver extends React.Component {
             let request = await fetch("https://aax.api.j-kit.me/api/v2/activation/" + checksum);
             let result = await request.json();
             const { success, activationBytes } = result;
-            if (success === true) {
-                this.setState({ activationBytes: activationBytes });
-                this.addNotification("Successfully resolved the activation bytes");
-            } else {
+
+            if (success !== true) {
                 this.setState({ activationBytes: 'UNKNOWN' });
                 this.addNotification("An error occured while resolving the activation bytes, please check your inputs", false);
+                return;
+            }
+
+            if (success === true) {
+                const calculatedChecksum = await AaxHashAlgorithm.CalculateChecksum(activationBytes);
+                if (calculatedChecksum == checksum) {
+                    this.setState({ activationBytes: activationBytes });
+                    this.addNotification("Successfully resolved the activation bytes");
+                    return;
+                }
+                
+                this.setState({ activationBytes: "API ERROR" });
+                this.addNotification("An unexpected error occured while resolving the activation bytes, please try again", false);
+
             }
         } catch (error) {
             this.setState({ activationBytes: error });
diff --git a/src/Utils/AaxHashAlgorithm.js b/src/Utils/AaxHashAlgorithm.js
new file mode 100644
index 0000000..244f232
--- /dev/null
+++ b/src/Utils/AaxHashAlgorithm.js
@@ -0,0 +1,44 @@
+export default class AaxHashAlgorithm {
+    static Instance = new AaxHashAlgorithm();
+ 
+    __fixed_key = [0x77, 0x21, 0x4d, 0x4b, 0x19, 0x6a, 0x87, 0xcd, 0x52, 0x00, 0x45, 0xfd, 0x20, 0xa5, 0x1d, 0x67];
+ 
+ 
+    // Convert a hex string to a byte array
+    __hexToBytes(hex) {
+        for (var bytes = [], c = 0; c < hex.length; c += 2)
+            bytes.push(parseInt(hex.substr(c, 2), 16));
+ 
+        return bytes;
+    }
+ 
+    // Convert a byte array to a hex string
+    __bytesToHex(bytes) {
+        for (var hex = [], i = 0; i < bytes.length; i++) {
+            var current = bytes[i] < 0 ? bytes[i] + 256 : bytes[i];
+            hex.push((current >>> 4).toString(16));
+            hex.push((current & 0xF).toString(16));
+        }
+        return hex.join("");
+    }
+ 
+    async __HashData(data) {
+        let source = new Uint8Array(data);
+        let buffer = await crypto.subtle.digest('SHA-1', source);
+        return Array.from(new Uint8Array(buffer));
+    }
+ 
+    async CalculateChecksum(activationBytes) {
+        let data = this.__hexToBytes(activationBytes);
+ 
+        let intermediate_key = await this.__HashData(this.__fixed_key.concat(data));
+        let intermediate_iv = await this.__HashData(this.__fixed_key.concat(intermediate_key).concat(data));
+        let checksum = await this.__HashData(intermediate_key.slice(0, 16).concat(intermediate_iv.slice(0, 16)));
+ 
+        return this.__bytesToHex(checksum);
+    }
+ 
+    static async CalculateChecksum(activationBytes){
+        return AaxHashAlgorithm.Instance.CalculateChecksum(activationBytes);
+    }
+}
\ No newline at end of file