Added unit tests for C# block cipher modes

Author: fegge

csharp/ql/test/experimental/library-tests/quantum/dotnet/ciphers/AesCfbExample.cs

@@ -0,0 +1,102 @@
+using System;
+using System.IO;
+using System.Security.Cryptography;
+using System.Text;
+
+namespace QuantumExamples.Cryptography
+{
+    public class AesCfbExample
+    {
+        public static void RunExample()
+        {
+            const string originalMessage = "This is a secret message!";
+
+            byte[] key = GenerateRandomKey();
+            byte[] iv = GenerateRandomIV();
+
+            byte[] encryptedData = EncryptStringWithCfb(originalMessage, key, iv);
+            string decryptedMessage = DecryptStringWithCfb(encryptedData, key, iv);
+
+            bool isSuccessful = originalMessage == decryptedMessage;
+            Console.WriteLine("Decryption successful: {0}", isSuccessful);
+        }
+
+        private static byte[] EncryptStringWithCfb(string plainText, byte[] key, byte[] iv)
+        {
+            byte[] encrypted;
+
+            using (Aes aes = Aes.Create())
+            {
+                // Set the key and IV on the AES instance.
+                aes.Key = key;
+                aes.IV = iv;
+                aes.Mode = CipherMode.CFB;
+                aes.Padding = PaddingMode.None;
+
+                ICryptoTransform encryptor = aes.CreateEncryptor();
+                byte[] plainBytes = Encoding.UTF8.GetBytes(plainText);
+
+                // Create an empty memory stream and write the plaintext to the crypto stream.
+                using (MemoryStream msEncrypt = new MemoryStream())
+                {
+                    using (CryptoStream csEncrypt = new CryptoStream(msEncrypt, encryptor, CryptoStreamMode.Write))
+                    {
+                        csEncrypt.Write(plainBytes, 0, plainBytes.Length);
+                        csEncrypt.FlushFinalBlock();
+                    }
+                    encrypted = msEncrypt.ToArray();
+                }
+            }
+            return encrypted;
+        }
+
+        private static string DecryptStringWithCfb(byte[] cipherText, byte[] key, byte[] iv)
+        {
+            string decrypted;
+
+            using (Aes aes = Aes.Create())
+            {
+                aes.Mode = CipherMode.CFB;
+                aes.Padding = PaddingMode.None;
+
+                // Pass the key and IV to the decryptor directly.
+                ICryptoTransform decryptor = aes.CreateDecryptor(key, iv);
+
+                // Pass the ciphertext to the memory stream directly.
+                using (MemoryStream msDecrypt = new MemoryStream(cipherText))
+                {
+                    using (CryptoStream csDecrypt = new CryptoStream(msDecrypt, decryptor, CryptoStreamMode.Read))
+                    {
+                        using (MemoryStream msPlain = new MemoryStream())
+                        {
+                            csDecrypt.CopyTo(msPlain);
+                            byte[] plainBytes = msPlain.ToArray();
+                            decrypted = Encoding.UTF8.GetString(plainBytes);
+                        }
+                    }
+                }
+            }
+            return decrypted;
+        }
+
+        private static byte[] GenerateRandomKey()
+        {
+            byte[] key = new byte[32]; // 256-bit key
+            using (var rng = RandomNumberGenerator.Create())
+            {
+                rng.GetBytes(key);
+            }
+            return key;
+        }
+
+        private static byte[] GenerateRandomIV()
+        {
+            byte[] iv = new byte[16]; // 128-bit IV
+            using (var rng = RandomNumberGenerator.Create())
+            {
+                rng.GetBytes(iv);
+            }
+            return iv;
+        }
+    }
+}

csharp/ql/test/experimental/library-tests/quantum/dotnet/ciphers/cipher_key_sources.expected

@@ -0,0 +1,2 @@
+| AesCfbExample.cs:42:53:42:114 | EncryptOperation | AesCfbExample.cs:31:17:31:23 | Key | AesCfbExample.cs:87:30:87:32 | RandomNumberGeneration |
+| AesCfbExample.cs:68:53:68:113 | DecryptOperation | AesCfbExample.cs:63:66:63:68 | Key | AesCfbExample.cs:87:30:87:32 | RandomNumberGeneration |

csharp/ql/test/experimental/library-tests/quantum/dotnet/ciphers/cipher_key_sources.ql

@@ -0,0 +1,6 @@
+import csharp
+import experimental.quantum.Language
+
+from Crypto::CipherOperationNode op, Crypto::KeyArtifactNode k
+where op.getAKey() = k
+select op, k, k.getSourceNode()

csharp/ql/test/experimental/library-tests/quantum/dotnet/ciphers/cipher_nonce_sources.expected

@@ -0,0 +1,2 @@
+| AesCfbExample.cs:42:53:42:114 | EncryptOperation | AesCfbExample.cs:32:17:32:22 | Nonce | AesCfbExample.cs:97:30:97:31 | RandomNumberGeneration |
+| AesCfbExample.cs:68:53:68:113 | DecryptOperation | AesCfbExample.cs:63:71:63:72 | Nonce | AesCfbExample.cs:97:30:97:31 | RandomNumberGeneration |

csharp/ql/test/experimental/library-tests/quantum/dotnet/ciphers/cipher_nonce_sources.ql

@@ -0,0 +1,6 @@
+import csharp
+import experimental.quantum.Language
+
+from Crypto::CipherOperationNode op, Crypto::NonceArtifactNode n
+where op.getANonce() = n
+select op, n, n.getSourceNode()

csharp/ql/test/experimental/library-tests/quantum/dotnet/ciphers/cipher_operations.expected

@@ -0,0 +1,2 @@
+| AesCfbExample.cs:42:53:42:114 | EncryptOperation | AesCfbExample.cs:44:41:44:50 | Message | AesCfbExample.cs:47:33:47:51 | KeyOperationOutput | AesCfbExample.cs:31:17:31:23 | Key | AesCfbExample.cs:32:17:32:22 | Nonce | AesCfbExample.cs:28:30:28:41 | KeyOperationAlgorithm | Encrypt |
+| AesCfbExample.cs:68:53:68:113 | DecryptOperation | AesCfbExample.cs:66:66:66:75 | Message | AesCfbExample.cs:73:49:73:65 | KeyOperationOutput | AesCfbExample.cs:63:66:63:68 | Key | AesCfbExample.cs:63:71:63:72 | Nonce | AesCfbExample.cs:57:30:57:41 | KeyOperationAlgorithm | Decrypt |

csharp/ql/test/experimental/library-tests/quantum/dotnet/ciphers/cipher_operations.ql

@@ -0,0 +1,6 @@
+import csharp
+import experimental.quantum.Language
+
+from Crypto::CipherOperationNode n
+select n, n.getAnInputArtifact(), n.getAnOutputArtifact(), n.getAKey(), n.getANonce(),
+  n.getAnAlgorithmOrGenericSource(), n.getKeyOperationSubtype()

csharp/ql/test/experimental/library-tests/quantum/dotnet/ciphers/options

@@ -0,0 +1,2 @@
+semmle-extractor-options: /nostdlib /noconfig
+semmle-extractor-options: --load-sources-from-project:${testdir}/../../../../../resources/stubs/_frameworks/Microsoft.NETCore.App/Microsoft.NETCore.App.csproj