diff --git a/SMBLibrary.Tests/SMB2EncryptionTests.cs b/SMBLibrary.Tests/SMB2EncryptionTests.cs index f27e6f3..f5a243a 100644 --- a/SMBLibrary.Tests/SMB2EncryptionTests.cs +++ b/SMBLibrary.Tests/SMB2EncryptionTests.cs @@ -39,10 +39,76 @@ namespace SMBLibrary.Tests Assert.IsTrue(ByteUtils.AreByteArraysEqual(expectedDecryptionKey, decryptionKey)); } + [TestMethod] + public void TestEncryption() + { + byte[] encryptionKey = new byte[] { 0x26, 0x1B, 0x72, 0x35, 0x05, 0x58, 0xF2, 0xE9, 0xDC, 0xF6, 0x13, 0x07, 0x03, 0x83, 0xED, 0xBF }; + byte[] nonce = new byte[] { 0x66, 0xE6, 0x9A, 0x11, 0x18, 0x92, 0x58, 0x4F, 0xB5, 0xED, 0x52 }; + ulong sessionID = 0x8e40014000011; + + byte[] message = new byte[] { 0xFE, 0x53, 0x4D, 0x42, 0x40, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x09, 0x00, 0x40, 0x00, + 0x08, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x04, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, + 0xFF, 0xFE, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00, 0x11, 0x00, 0x00, 0x14, 0x00, 0xE4, 0x08, 0x00, + 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, + 0x31, 0x00, 0x70, 0x00, 0x17, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, + 0x15, 0x01, 0x00, 0x00, 0x39, 0x00, 0x00, 0x02, 0x01, 0x00, 0x00, 0x00, 0x39, 0x02, 0x00, 0x00, + 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x70, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, + 0x53, 0x6D, 0x62, 0x33, 0x20, 0x65, 0x6E, 0x63, 0x72, 0x79, 0x70, 0x74, 0x69, 0x6F, 0x6E, 0x20, + 0x74, 0x65, 0x73, 0x74, 0x69, 0x6E, 0x67}; + + byte[] expectedEncrypted = new byte[] { 0x25, 0xC8, 0xFE, 0xE1, 0x66, 0x05, 0xA4, 0x37, 0x83, 0x2D, 0x1C, 0xD5, 0x2D, 0xA9, 0xF4, 0x64, + 0x53, 0x33, 0x48, 0x2A, 0x17, 0x5F, 0xE5, 0x38, 0x45, 0x63, 0xF4, 0x5F, 0xCD, 0xAF, 0xAE, 0xF3, + 0x8B, 0xC6, 0x2B, 0xA4, 0xD5, 0xC6, 0x28, 0x97, 0x99, 0x66, 0x25, 0xA4, 0x4C, 0x29, 0xBE, 0x56, + 0x58, 0xDE, 0x2E, 0x61, 0x17, 0x58, 0x57, 0x79, 0xE7, 0xB5, 0x9F, 0xFD, 0x97, 0x12, 0x78, 0xD0, + 0x85, 0x80, 0xD7, 0xFA, 0x89, 0x9E, 0x41, 0x0E, 0x91, 0x0E, 0xAB, 0xF5, 0xAA, 0x1D, 0xB4, 0x30, + 0x50, 0xB3, 0x3B, 0x49, 0x18, 0x26, 0x37, 0x75, 0x9A, 0xC1, 0x5D, 0x84, 0xBF, 0xCD, 0xF5, 0xB6, + 0xB2, 0x38, 0x99, 0x3C, 0x0F, 0x4C, 0xF4, 0xD6, 0x01, 0x20, 0x23, 0xF6, 0xC6, 0x27, 0x29, 0x70, + 0x75, 0xD8, 0x4B, 0x78, 0x03, 0x91, 0x2D, 0x0A, 0x96, 0x39, 0x63, 0x44, 0x53, 0x59, 0x5E, 0xF3, + 0xE3, 0x3F, 0xFE, 0x4E, 0x7A, 0xC2, 0xAB }; + + byte[] expectedSignature = new byte[] { 0x81, 0xA2, 0x86, 0x53, 0x54, 0x15, 0x44, 0x5D, 0xAE, 0x39, 0x39, 0x21, 0xE4, 0x4F, 0xA4, 0x2E }; + + byte[] signature; + byte[] encryptedMessage = SMB2Cryptography.EncryptMessage(encryptionKey, nonce, message, sessionID, out signature); + + Assert.IsTrue(ByteUtils.AreByteArraysEqual(expectedEncrypted, encryptedMessage)); + // The associated data in this sample include non-zero nonce padding so we ignore signature validation + } + + [TestMethod] + public void TestDecryption() + { + byte[] decryptionKey = new byte[] { 0x8F, 0xE2, 0xB5, 0x7E, 0xC3, 0x4D, 0x2D, 0xB5, 0xB1, 0xA9, 0x72, 0x7F, 0x52, 0x6B, 0xBD, 0xB5 }; + + byte[] transformedPacket = new byte[] { 0xFD, 0x53, 0x4D, 0x42, 0xA6, 0x01, 0x55, 0x30, 0xA1, 0x8F, 0x6D, 0x9A, 0xFF, 0xE2, 0x2A, 0xFA, + 0xE8, 0xE6, 0x64, 0x84, 0x86, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x11, 0x00, 0x00, 0x14, + 0x00, 0xE4, 0x08, 0x00, 0x50, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x11, 0x00, 0x00, 0x14, + 0x00, 0xE4, 0x08, 0x00, 0xDB, 0xF4, 0x64, 0x35, 0xC5, 0xF1, 0x41, 0x69, 0x29, 0x3C, 0xE0, 0x79, + 0xE3, 0x44, 0x47, 0x9B, 0xF6, 0x70, 0x22, 0x7E, 0x49, 0x87, 0x3F, 0x45, 0x86, 0x72, 0xC3, 0x09, + 0x8D, 0xAC, 0x46, 0x7D, 0xD5, 0x80, 0x9F, 0x36, 0x9D, 0x67, 0x40, 0x91, 0x66, 0x51, 0x57, 0x87, + 0x14, 0x83, 0xE0, 0x1F, 0x7B, 0xEC, 0xD0, 0x20, 0x64, 0xEA, 0xC3, 0xE2, 0x35, 0xF9, 0x13, 0x66, + 0x8B, 0xBC, 0x2F, 0x09, 0x79, 0x80, 0xD4, 0xB3, 0x78, 0xF1, 0x99, 0x3E, 0xFF, 0x6E, 0x60, 0xD1, + 0x77, 0x30, 0x9E, 0x5B }; + + byte[] expectedDecryptedMessage = new byte[] { 0xFE, 0x53, 0x4D, 0x42, 0x40, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x09, 0x00, 0x21, 0x00, + 0x09, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x04, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, + 0xFF, 0xFE, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00, 0x11, 0x00, 0x00, 0x14, 0x00, 0xE4, 0x08, 0x00, + 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, + 0x11, 0x00, 0x00, 0x00, 0x17, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 }; + + SMB2TransformHeader transformHeader = new SMB2TransformHeader(transformedPacket, 0); + byte[] encryptedMessage = ByteReader.ReadBytes(transformedPacket, SMB2TransformHeader.Length, (int)transformHeader.OriginalMessageSize); + byte[] decryptedMessage = SMB2Cryptography.DecryptMessage(decryptionKey, transformHeader, encryptedMessage); + + Assert.IsTrue(ByteUtils.AreByteArraysEqual(expectedDecryptedMessage, decryptedMessage)); + } + public void TestAll() { TestEncryptionKeyGeneration(); TestDecryptionKeyGeneration(); + TestEncryption(); + TestDecryption(); } } } diff --git a/SMBLibrary/SMB2/SMB2Cryptography.cs b/SMBLibrary/SMB2/SMB2Cryptography.cs index 5f510ee..b88d855 100644 --- a/SMBLibrary/SMB2/SMB2Cryptography.cs +++ b/SMBLibrary/SMB2/SMB2Cryptography.cs @@ -12,6 +12,8 @@ namespace SMBLibrary.SMB2 { internal class SMB2Cryptography { + private const int AesCcmNonceLength = 11; + public static byte[] CalculateSignature(byte[] signingKey, SMB2Dialect dialect, byte[] buffer, int offset, int paddedLength) { if (dialect == SMB2Dialect.SMB202 || dialect == SMB2Dialect.SMB210) @@ -74,6 +76,58 @@ namespace SMBLibrary.SMB2 return SP800_1008.DeriveKey(hmac, label, context, 128); } + /// + /// Encyrpt message and prefix with SMB2 TransformHeader + /// + public static byte[] TransformMessage(byte[] key, byte[] message, ulong sessionID) + { + byte[] nonce = GenerateAesCcmNonce(); + byte[] signature; + byte[] encryptedMessage = EncryptMessage(key, nonce, message, sessionID, out signature); + SMB2TransformHeader transformHeader = CreateTransformHeader(nonce, message.Length, sessionID); + transformHeader.Signature = signature; + + byte[] buffer = new byte[SMB2TransformHeader.Length + message.Length]; + transformHeader.WriteBytes(buffer, 0); + ByteWriter.WriteBytes(buffer, SMB2TransformHeader.Length, encryptedMessage); + return buffer; + } + + public static byte[] EncryptMessage(byte[] key, byte[] nonce, byte[] message, ulong sessionID, out byte[] signature) + { + SMB2TransformHeader transformHeader = CreateTransformHeader(nonce, message.Length, sessionID); + byte[] associatedata = transformHeader.GetAssociatedData(); + return AesCcm.Encrypt(key, nonce, message, associatedata, SMB2TransformHeader.SignatureLength, out signature); + } + + public static byte[] DecryptMessage(byte[] key, SMB2TransformHeader transformHeader, byte[] encryptedMessage) + { + byte[] associatedData = transformHeader.GetAssociatedData(); + byte[] aesCcmNonce = ByteReader.ReadBytes(transformHeader.Nonce, 0, AesCcmNonceLength); + return AesCcm.DecryptAndAuthenticate(key, aesCcmNonce, encryptedMessage, associatedData, transformHeader.Signature); + } + + private static SMB2TransformHeader CreateTransformHeader(byte[] nonce, int originalMessageLength, ulong sessionID) + { + byte[] nonceWithPadding = new byte[SMB2TransformHeader.NonceLength]; + Array.Copy(nonce, nonceWithPadding, nonce.Length); + + SMB2TransformHeader transformHeader = new SMB2TransformHeader(); + transformHeader.Nonce = nonceWithPadding; + transformHeader.OriginalMessageSize = (uint)originalMessageLength; + transformHeader.Flags = SMB2TransformHeaderFlags.Encrypted; + transformHeader.SessionId = sessionID; + + return transformHeader; + } + + private static byte[] GenerateAesCcmNonce() + { + byte[] aesCcmNonce = new byte[AesCcmNonceLength]; + new Random().NextBytes(aesCcmNonce); + return aesCcmNonce; + } + private static byte[] GetNullTerminatedAnsiString(string value) { byte[] result = new byte[value.Length + 1];