add cryptographic key model to the crypto-js library

Author: erik-krogh

javascript/ql/lib/semmle/javascript/frameworks/CryptoLibraries.qll

@@ -330,6 +330,35 @@ private module CryptoJS {
       )
     }
   }
+
+  private class CreateKey extends CryptographicKeyCreation, DataFlow::CallNode {
+    string algorithm;
+    int optionArg;
+
+    CreateKey() {
+      // var key = CryptoJS.PBKDF2(password, salt, { keySize: 8 });
+      this =
+        getAlgorithmExpr(any(CryptographicAlgorithm algo | algo.getName() = algorithm)).getACall() and
+      optionArg = 2
+      or
+      // var key = CryptoJS.algo.PBKDF2.create({ keySize: 8 });
+      this =
+        DataFlow::moduleMember("crypto-js", "algo")
+            .getAPropertyRead(algorithm)
+            .getAMethodCall("create") and
+      optionArg = 0
+    }
+
+    override CryptographicAlgorithm getAlgorithm() { result.matchesName(algorithm) }
+
+    override int getSize() {
+      result = getOptionArgument(optionArg, "keySize").getIntValue() * 32 // size is in words
+      or
+      result = getArgument(optionArg).getIntValue() * 32 // size is in words
+    }
+
+    override predicate isSymmetricKey() { any() }
+  }
 }
 
 /**

javascript/ql/lib/semmle/javascript/security/CryptoAlgorithms.qll

@@ -46,7 +46,7 @@ private module AlgorithmNames {
     name = ["ARGON2", "PBKDF2", "BCRYPT", "SCRYPT"]
   }
 
-  predicate isWeakPasswordHashingAlgorithm(string name) { none() }
+  predicate isWeakPasswordHashingAlgorithm(string name) { name = "EVPKDF" }
 }
 
 private import AlgorithmNames

javascript/ql/test/query-tests/Security/CWE-326/InsufficientKeySize.expected

@@ -1,2 +1,5 @@
 | tst.js:3:14:3:71 | crypto. ... 1024 }) | Creation of an asymmetric RSA key uses 1024 bits, which is below 2048 and considered breakable. |
 | tst.js:7:14:7:59 | crypto. ... : 64 }) | Creation of an symmetric key uses 64 bits, which is below 128 and considered breakable. |
+| tst.js:14:14:14:56 | CryptoJ ... e: 2 }) | Creation of an symmetric PBKDF2 key uses 64 bits, which is below 128 and considered breakable. |
+| tst.js:15:14:15:60 | CryptoJ ... e: 2 }) | Creation of an symmetric PBKDF2 key uses 64 bits, which is below 128 and considered breakable. |
+| tst.js:16:14:16:60 | CryptoJ ... e: 2 }) | Creation of an symmetric EVPKDF key uses 64 bits, which is below 128 and considered breakable. |

javascript/ql/test/query-tests/Security/CWE-326/tst.js

@@ -6,4 +6,11 @@ const good1 = crypto.generateKeyPairSync("rsa", { modulusLength: 4096 }); // OK
 
 const bad2 = crypto.generateKeySync("hmac", { length: 64 }); // NOT OK
 
-const good2 = crypto.generateKeySync("aes", { length: 256 }); // OK
+const good2 = crypto.generateKeySync("aes", { length: 256 }); // OK
+
+var CryptoJS = require("crypto-js");
+
+const bad3 = CryptoJS.algo.PBKDF2.create({ keySize: 2 }); // NOT OK
+const bad4 = CryptoJS.PBKDF2(password, salt, { keySize: 2 }); // NOT OK
+const bad5 = CryptoJS.EvpKDF(password, salt, { keySize: 2 }); // NOT OK
+const bad4 = CryptoJS.PBKDF2(password, salt, { keySize: 8 }); // OK