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SMB2Cryptography: Added logic for SMB 3.0 encryption

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TalAloni 2020-11-28 18:52:35 +02:00
parent 34ca830f78
commit d0b721d621
2 changed files with 120 additions and 0 deletions
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66
SMBLibrary.Tests/SMB2EncryptionTests.cs
View file

@ -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();
}
}
}

54
SMBLibrary/SMB2/SMB2Cryptography.cs
View file

@ -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);
}
/// <summary>
/// Encyrpt message and prefix with SMB2 TransformHeader
/// </summary>
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];