protected SslHandshakeStatus ProcessAlert(RecordMessage message)
{
if (message.length != 2 || message.fragment.Length != 2)
{
throw new SslException(AlertDescription.RecordOverflow, "The alert message is invalid.");
}
try {
AlertLevel level = (AlertLevel)message.fragment[0];
AlertDescription description = (AlertDescription)message.fragment[1];
if (level == AlertLevel.Fatal)
{
throw new SslException(description, "The other side has sent a failure alert.");
}
SslHandshakeStatus ret;
if (description == AlertDescription.CloseNotify)
{
if (m_State == HandshakeType.ShuttingDown) // true if we've already sent a shutdown notification
// close connection
{
ret = new SslHandshakeStatus(SslStatus.Close, null);
}
else
{
// send a shutdown notifications, and then close the connection
ret = new SslHandshakeStatus(SslStatus.Close, GetControlBytes(ControlType.Shutdown));
}
}
else
{
ret = new SslHandshakeStatus(SslStatus.OK, null);
}
return(ret);
} catch (SslException t) {
throw t;
} catch (Exception e) {
throw new SslException(e, AlertDescription.InternalError, "There was an internal error.");
}
}
protected abstract SslHandshakeStatus ProcessChangeCipherSpec(RecordMessage message);
protected override SslHandshakeStatus ProcessChangeCipherSpec(RecordMessage message)
{
if (message.length != 1 || message.fragment[0] != 1)
throw new SslException(AlertDescription.IllegalParameter, "The ChangeCipherSpec message was invalid.");
if (m_State == HandshakeType.ServerHelloDone) {
m_RecordLayer.ChangeRemoteState(null, m_CipherSuite.Decryptor, m_CipherSuite.RemoteHasher);
return new SslHandshakeStatus(SslStatus.MessageIncomplete, null); // needs a finished message
} else {
throw new SslException(AlertDescription.UnexpectedMessage, "ChangeCipherSpec message must be preceded by a ServerHelloDone message.");
}
}
protected abstract SslHandshakeStatus ProcessChangeCipherSpec(RecordMessage message);
protected SslHandshakeStatus ProcessAlert(RecordMessage message)
{
if (message.length != 2 || message.fragment.Length != 2)
throw new SslException(AlertDescription.RecordOverflow, "The alert message is invalid.");
try {
AlertLevel level = (AlertLevel)message.fragment[0];
AlertDescription description = (AlertDescription)message.fragment[1];
if (level == AlertLevel.Fatal)
throw new SslException(description, "The other side has sent a failure alert.");
SslHandshakeStatus ret;
if (description == AlertDescription.CloseNotify) {
if (m_State == HandshakeType.ShuttingDown) { // true if we've already sent a shutdown notification
// close connection
ret = new SslHandshakeStatus(SslStatus.Close, null);
} else {
// send a shutdown notifications, and then close the connection
ret = new SslHandshakeStatus(SslStatus.Close, GetControlBytes(ControlType.Shutdown));
}
} else {
ret = new SslHandshakeStatus(SslStatus.OK, null);
}
return ret;
} catch (SslException t) {
throw t;
} catch (Exception e) {
throw new SslException(e, AlertDescription.InternalError, "There was an internal error.");
}
}
// processes Handshake & ChangeCipherSpec messages
public SslHandshakeStatus ProcessMessages(RecordMessage message)
{
if (message == null)
throw new ArgumentNullException();
SslHandshakeStatus ret;
if (message.contentType == ContentType.ChangeCipherSpec) {
ret = ProcessChangeCipherSpec(message);
m_State = HandshakeType.ChangeCipherSpec;
} else if (message.contentType == ContentType.Handshake) {
ret = new SslHandshakeStatus();
// copy the new bytes and the old bytes in one buffer
MemoryStream ms = new MemoryStream();
byte[] fullbuffer = new byte[m_IncompleteMessage.Length + message.length];
Array.Copy(m_IncompleteMessage, 0, fullbuffer, 0, m_IncompleteMessage.Length);
Array.Copy(message.fragment, 0, fullbuffer, m_IncompleteMessage.Length, message.length);
// loop through all messages in buffer, if any
int offset = 0;
HandshakeMessage hm = GetHandshakeMessage(fullbuffer, offset);
while(hm != null) {
offset += hm.fragment.Length + 4;
SslHandshakeStatus status = ProcessMessage(hm);
if (status.Message != null) {
ms.Write(status.Message, 0, status.Message.Length);
}
ret.Status = status.Status;
// go to next message
m_State = hm.type;
hm = GetHandshakeMessage(fullbuffer, offset);
}
if (offset > 0) {
m_IncompleteMessage = new byte[fullbuffer.Length - offset];
Array.Copy(fullbuffer, offset, m_IncompleteMessage, 0, m_IncompleteMessage.Length);
} else {
m_IncompleteMessage = fullbuffer;
}
if (ms.Length > 0) {
ret.Message = ms.ToArray();
}
ms.Close();
} else { // message.contentType == ContentType.Alert
ret = ProcessAlert(message);
}
return ret;
}
public SslRecordStatus ProcessBytes(byte[] buffer, int offset, int size) {
if (buffer == null)
throw new ArgumentNullException();
if (offset < 0 || offset + size > buffer.Length || size <= 0)
throw new ArgumentException();
SslRecordStatus ret = new SslRecordStatus();
ret.Status = SslStatus.MessageIncomplete;
MemoryStream decrypted = new MemoryStream();
MemoryStream protocol = new MemoryStream();
// copy the new bytes and the old bytes in one buffer
byte[] fullbuffer = new byte[m_IncompleteMessage.Length + size];
Array.Copy(m_IncompleteMessage, 0, fullbuffer, 0, m_IncompleteMessage.Length);
Array.Copy(buffer, offset, fullbuffer, m_IncompleteMessage.Length, size);
// extract all record messages, if any, and process them
int recordSize = 0;
int recordLength;
while(IsRecordMessageComplete(fullbuffer, recordSize)) {
RecordMessage message = new RecordMessage(fullbuffer, recordSize);
recordLength = message.length + 5;
UnwrapMessage(message); // decrypt and verify message
// process message
if (message.contentType == ContentType.ApplicationData) {
if (!m_HandshakeLayer.IsNegotiating()) {
decrypted.Write(message.fragment, 0, message.fragment.Length);
} else {
throw new SslException(AlertDescription.UnexpectedMessage, "The handshake procedure was not completed successfully before application data was received.");
}
ret.Status = SslStatus.OK;
} else { // handshake message or change cipher spec message
SslHandshakeStatus status = m_HandshakeLayer.ProcessMessages(message);
if (status.Message != null)
protocol.Write(status.Message, 0, status.Message.Length);
ret.Status = status.Status;
}
recordSize += recordLength;
}
// copy remaining data [incomplete record]
if (recordSize > 0) {
m_IncompleteMessage = new byte[fullbuffer.Length - recordSize];
Array.Copy(fullbuffer, recordSize, m_IncompleteMessage, 0, m_IncompleteMessage.Length);
} else {
m_IncompleteMessage = fullbuffer;
}
if (decrypted.Length > 0) {
ret.Decrypted = decrypted.ToArray();
}
decrypted.Close();
if (protocol.Length > 0) {
ret.Buffer = protocol.ToArray();
}
protocol.Close();
return ret;
}
} //*/
protected void UnwrapMessage(RecordMessage message) {
if (message.length != message.fragment.Length)
throw new SslException(AlertDescription.IllegalParameter, "Message length is invalid.");
byte[] remoteMac = null, decrypted = null, localMac = null;
bool cipherError = false;
// decrypt and verify the message
if (m_BulkDecryption != null) {
if (message.length <= m_RemoteHasher.HashSize / 8)
throw new SslException(AlertDescription.DecodeError, "Message is too small.");
if (message.length % m_BulkDecryption.OutputBlockSize != 0)
throw new SslException(AlertDescription.DecryptError, "Message length is invalid.");
// decrypt the message
if (m_BulkDecryption.OutputBlockSize == 1) { // is stream cipher?
decrypted = new byte[message.length];
m_BulkDecryption.TransformBlock(message.fragment, 0, message.length, decrypted, 0);
remoteMac = new byte[m_RemoteHasher.HashSize / 8];
Array.Copy(decrypted, message.length - remoteMac.Length, remoteMac, 0, remoteMac.Length);
message.fragment = new byte[decrypted.Length - remoteMac.Length];
Array.Copy(decrypted, 0, message.fragment, 0, message.fragment.Length);
message.length = (ushort)message.fragment.Length;
} else { // cipher is block cipher
decrypted = new byte[message.fragment.Length];
m_BulkDecryption.TransformBlock(message.fragment, 0, decrypted.Length, decrypted, 0);
byte padding = decrypted[decrypted.Length - 1];
if (message.length < padding + m_RemoteHasher.HashSize / 8 + 1) {
cipherError = true;
remoteMac = new byte[m_RemoteHasher.HashSize / 8];
} else {
int realSize = (message.length - padding) - 1;
remoteMac = new byte[m_RemoteHasher.HashSize / 8];
Array.Copy(decrypted, realSize - remoteMac.Length, remoteMac, 0, remoteMac.Length);
message.fragment = new byte[realSize - remoteMac.Length];
Array.Copy(decrypted, 0, message.fragment, 0, message.fragment.Length);
message.length = (ushort)message.fragment.Length;
if (m_HandshakeLayer.GetProtocol() == SecureProtocol.Tls1) {
// check padding
for(int i = realSize; i < decrypted.Length; i++) {
if (decrypted[i] != padding) {
cipherError = true;
}
}
}
}
}
// calculate the MAC
localMac = GetULongBytes(m_InputSequenceNumber);
m_RemoteHasher.Initialize();
m_RemoteHasher.TransformBlock(localMac, 0, localMac.Length, localMac, 0); // seq_num + ..
localMac = message.ToBytes();
if (m_HandshakeLayer.GetProtocol() == SecureProtocol.Tls1) {
m_RemoteHasher.TransformFinalBlock(localMac, 0, localMac.Length); // .. + TLSCompressed.type + TLSCompressed.version + TLSCompressed.length + TLSCompressed.fragment
} else if (m_HandshakeLayer.GetProtocol() == SecureProtocol.Ssl3) {
m_RemoteHasher.TransformBlock(localMac, 0, 1, localMac, 0); // type
m_RemoteHasher.TransformFinalBlock(localMac, 3, localMac.Length - 3); // length + fragment
} else {
throw new NotSupportedException("Only SSL3 and TLS1 are supported");
}
localMac = m_RemoteHasher.Hash;
// compare MACs
for(int i = 0; i < remoteMac.Length; i++) {
if (remoteMac[i] != localMac[i]) {
cipherError = true;
}
}
// throw cipher error, if necessary
if (cipherError)
throw new SslException(AlertDescription.BadRecordMac, "An error occurred during the decryption and verification process.");
}
// decompress the message
if (m_RemoteCompressor != null) {
message.fragment = m_RemoteCompressor.Decompress(message.fragment);
message.length = (ushort)message.fragment.Length;
}
// final adjustments
message.messageType = MessageType.PlainText;
m_InputSequenceNumber++;
}
protected void WrapMessage(RecordMessage message) {
if (message.length != message.fragment.Length)
throw new SslException(AlertDescription.IllegalParameter, "Message length is invalid.");
byte[] mac = null;
try {
// compress the message
if (m_LocalCompressor != null) {
message.fragment = m_LocalCompressor.Compress(message.fragment);
message.length = (ushort)message.fragment.Length;
}
// encrypt the message and MAC
if (m_LocalHasher != null) {
// calculate the MAC
mac = GetULongBytes(m_OutputSequenceNumber);
m_LocalHasher.Initialize();
m_LocalHasher.TransformBlock(mac, 0, mac.Length, mac, 0); // seq_num + ..
mac = message.ToBytes();
if (m_HandshakeLayer.GetProtocol() == SecureProtocol.Tls1) {
m_LocalHasher.TransformFinalBlock(mac, 0, mac.Length); // .. + TLSCompressed.type + TLSCompressed.version + TLSCompressed.length + TLSCompressed.fragment
} else if (m_HandshakeLayer.GetProtocol() == SecureProtocol.Ssl3) {
m_LocalHasher.TransformBlock(mac, 0, 1, mac, 0); // type
m_LocalHasher.TransformFinalBlock(mac, 3, mac.Length - 3); // length + fragment
} else {
throw new NotSupportedException("Only SSL3 and TLS1 are supported");
}
mac = m_LocalHasher.Hash;
// encrypt the message
if (m_BulkEncryption.OutputBlockSize == 1) { // is stream cipher?
byte[] ret = new byte[message.length + mac.Length];
m_BulkEncryption.TransformBlock(message.fragment, 0, message.length, ret, 0);
m_BulkEncryption.TransformBlock(mac, 0, mac.Length, ret, message.length);
message.fragment = ret;
} else { // cipher is block cipher
int obs = m_BulkEncryption.OutputBlockSize;
byte padding = (byte)((obs - (message.length + mac.Length + 1) % obs) % obs);
byte[] ret = new byte[message.length + mac.Length + padding + 1];
Array.Copy(message.fragment, 0, ret, 0, message.length);
Array.Copy(mac, 0, ret, message.length, mac.Length);
if (m_HandshakeLayer.GetProtocol() == SecureProtocol.Tls1) {
for(int i = message.length + mac.Length; i < ret.Length; i++) {
ret[i] = padding;
}
} else {
byte[] buffer = new byte[ret.Length - message.length - mac.Length];
m_HandshakeLayer.RNG.GetBytes(buffer);
Array.Copy(buffer, 0, ret, message.length + mac.Length, buffer.Length);
ret[ret.Length - 1] = padding;
}
m_BulkEncryption.TransformBlock(ret, 0, ret.Length, ret, 0);
message.fragment = ret;
}
message.length = (ushort)message.fragment.Length;
}
} catch (Exception e) {
throw new SslException(e, AlertDescription.InternalError, "An exception occurred");
}
// final adjustments
message.messageType = MessageType.Encrypted;
m_OutputSequenceNumber++;
} //*/
protected byte[] InternalEncryptBytes(byte[] buffer, int offset, int size, ContentType type) { // only accepts sizes of less than 16Kb; does not do any error checking
byte[] bytes = new byte[size];
Array.Copy(buffer, offset, bytes, 0, size);
RecordMessage message = new RecordMessage(MessageType.PlainText, type, m_HandshakeLayer.GetVersion(), bytes);
WrapMessage(message);
return message.ToBytes();
}
public SslRecordStatus ProcessBytes(byte[] buffer, int offset, int size)
{
if (buffer == null)
{
throw new ArgumentNullException();
}
if (offset < 0 || offset + size > buffer.Length || size <= 0)
{
throw new ArgumentException();
}
SslRecordStatus ret = new SslRecordStatus();
ret.Status = SslStatus.MessageIncomplete;
MemoryStream decrypted = new MemoryStream();
MemoryStream protocol = new MemoryStream();
// copy the new bytes and the old bytes in one buffer
byte[] fullbuffer = new byte[m_IncompleteMessage.Length + size];
Array.Copy(m_IncompleteMessage, 0, fullbuffer, 0, m_IncompleteMessage.Length);
Array.Copy(buffer, offset, fullbuffer, m_IncompleteMessage.Length, size);
// extract all record messages, if any, and process them
int recordSize = 0;
int recordLength;
while (IsRecordMessageComplete(fullbuffer, recordSize))
{
RecordMessage message = new RecordMessage(fullbuffer, recordSize);
recordLength = message.length + 5;
UnwrapMessage(message); // decrypt and verify message
// process message
if (message.contentType == ContentType.ApplicationData)
{
if (!m_HandshakeLayer.IsNegotiating())
{
decrypted.Write(message.fragment, 0, message.fragment.Length);
}
else
{
throw new SslException(AlertDescription.UnexpectedMessage, "The handshake procedure was not completed successfully before application data was received.");
}
ret.Status = SslStatus.OK;
}
else // handshake message or change cipher spec message
{
SslHandshakeStatus status = m_HandshakeLayer.ProcessMessages(message);
if (status.Message != null)
{
protocol.Write(status.Message, 0, status.Message.Length);
}
ret.Status = status.Status;
}
recordSize += recordLength;
}
// copy remaining data [incomplete record]
if (recordSize > 0)
{
m_IncompleteMessage = new byte[fullbuffer.Length - recordSize];
Array.Copy(fullbuffer, recordSize, m_IncompleteMessage, 0, m_IncompleteMessage.Length);
}
else
{
m_IncompleteMessage = fullbuffer;
}
if (decrypted.Length > 0)
{
ret.Decrypted = decrypted.ToArray();
}
decrypted.Close();
if (protocol.Length > 0)
{
ret.Buffer = protocol.ToArray();
}
protocol.Close();
return(ret);
}
} //*/
protected void UnwrapMessage(RecordMessage message)
{
if (message.length != message.fragment.Length)
{
throw new SslException(AlertDescription.IllegalParameter, "Message length is invalid.");
}
byte[] remoteMac = null, decrypted = null, localMac = null;
bool cipherError = false;
// decrypt and verify the message
if (m_BulkDecryption != null)
{
if (message.length <= m_RemoteHasher.HashSize / 8)
{
throw new SslException(AlertDescription.DecodeError, "Message is too small.");
}
if (message.length % m_BulkDecryption.OutputBlockSize != 0)
{
throw new SslException(AlertDescription.DecryptError, "Message length is invalid.");
}
// decrypt the message
if (m_BulkDecryption.OutputBlockSize == 1) // is stream cipher?
{
decrypted = new byte[message.length];
m_BulkDecryption.TransformBlock(message.fragment, 0, message.length, decrypted, 0);
remoteMac = new byte[m_RemoteHasher.HashSize / 8];
Array.Copy(decrypted, message.length - remoteMac.Length, remoteMac, 0, remoteMac.Length);
message.fragment = new byte[decrypted.Length - remoteMac.Length];
Array.Copy(decrypted, 0, message.fragment, 0, message.fragment.Length);
message.length = (ushort)message.fragment.Length;
}
else // cipher is block cipher
{
decrypted = new byte[message.fragment.Length];
m_BulkDecryption.TransformBlock(message.fragment, 0, decrypted.Length, decrypted, 0);
byte padding = decrypted[decrypted.Length - 1];
if (message.length < padding + m_RemoteHasher.HashSize / 8 + 1)
{
cipherError = true;
remoteMac = new byte[m_RemoteHasher.HashSize / 8];
}
else
{
int realSize = (message.length - padding) - 1;
remoteMac = new byte[m_RemoteHasher.HashSize / 8];
Array.Copy(decrypted, realSize - remoteMac.Length, remoteMac, 0, remoteMac.Length);
message.fragment = new byte[realSize - remoteMac.Length];
Array.Copy(decrypted, 0, message.fragment, 0, message.fragment.Length);
message.length = (ushort)message.fragment.Length;
if (m_HandshakeLayer.GetProtocol() == SecureProtocol.Tls1)
{
// check padding
for (int i = realSize; i < decrypted.Length; i++)
{
if (decrypted[i] != padding)
{
cipherError = true;
}
}
}
}
}
// calculate the MAC
localMac = GetULongBytes(m_InputSequenceNumber);
m_RemoteHasher.Initialize();
m_RemoteHasher.TransformBlock(localMac, 0, localMac.Length, localMac, 0); // seq_num + ..
localMac = message.ToBytes();
if (m_HandshakeLayer.GetProtocol() == SecureProtocol.Tls1)
{
m_RemoteHasher.TransformFinalBlock(localMac, 0, localMac.Length); // .. + TLSCompressed.type + TLSCompressed.version + TLSCompressed.length + TLSCompressed.fragment
}
else if (m_HandshakeLayer.GetProtocol() == SecureProtocol.Ssl3)
{
m_RemoteHasher.TransformBlock(localMac, 0, 1, localMac, 0); // type
m_RemoteHasher.TransformFinalBlock(localMac, 3, localMac.Length - 3); // length + fragment
}
else
{
throw new NotSupportedException("Only SSL3 and TLS1 are supported");
}
localMac = m_RemoteHasher.Hash;
// compare MACs
for (int i = 0; i < remoteMac.Length; i++)
{
if (remoteMac[i] != localMac[i])
{
cipherError = true;
}
}
// throw cipher error, if necessary
if (cipherError)
{
throw new SslException(AlertDescription.BadRecordMac, "An error occurred during the decryption and verification process.");
}
}
// decompress the message
if (m_RemoteCompressor != null)
{
message.fragment = m_RemoteCompressor.Decompress(message.fragment);
message.length = (ushort)message.fragment.Length;
}
// final adjustments
message.messageType = MessageType.PlainText;
m_InputSequenceNumber++;
}
protected void WrapMessage(RecordMessage message)
{
if (message.length != message.fragment.Length)
{
throw new SslException(AlertDescription.IllegalParameter, "Message length is invalid.");
}
byte[] mac = null;
try {
// compress the message
if (m_LocalCompressor != null)
{
message.fragment = m_LocalCompressor.Compress(message.fragment);
message.length = (ushort)message.fragment.Length;
}
// encrypt the message and MAC
if (m_LocalHasher != null)
{
// calculate the MAC
mac = GetULongBytes(m_OutputSequenceNumber);
m_LocalHasher.Initialize();
m_LocalHasher.TransformBlock(mac, 0, mac.Length, mac, 0); // seq_num + ..
mac = message.ToBytes();
if (m_HandshakeLayer.GetProtocol() == SecureProtocol.Tls1)
{
m_LocalHasher.TransformFinalBlock(mac, 0, mac.Length); // .. + TLSCompressed.type + TLSCompressed.version + TLSCompressed.length + TLSCompressed.fragment
}
else if (m_HandshakeLayer.GetProtocol() == SecureProtocol.Ssl3)
{
m_LocalHasher.TransformBlock(mac, 0, 1, mac, 0); // type
m_LocalHasher.TransformFinalBlock(mac, 3, mac.Length - 3); // length + fragment
}
else
{
throw new NotSupportedException("Only SSL3 and TLS1 are supported");
}
mac = m_LocalHasher.Hash;
// encrypt the message
if (m_BulkEncryption.OutputBlockSize == 1) // is stream cipher?
{
byte[] ret = new byte[message.length + mac.Length];
m_BulkEncryption.TransformBlock(message.fragment, 0, message.length, ret, 0);
m_BulkEncryption.TransformBlock(mac, 0, mac.Length, ret, message.length);
message.fragment = ret;
}
else // cipher is block cipher
{
int obs = m_BulkEncryption.OutputBlockSize;
byte padding = (byte)((obs - (message.length + mac.Length + 1) % obs) % obs);
byte[] ret = new byte[message.length + mac.Length + padding + 1];
Array.Copy(message.fragment, 0, ret, 0, message.length);
Array.Copy(mac, 0, ret, message.length, mac.Length);
if (m_HandshakeLayer.GetProtocol() == SecureProtocol.Tls1)
{
for (int i = message.length + mac.Length; i < ret.Length; i++)
{
ret[i] = padding;
}
}
else
{
byte[] buffer = new byte[ret.Length - message.length - mac.Length];
m_HandshakeLayer.RNG.GetBytes(buffer);
Array.Copy(buffer, 0, ret, message.length + mac.Length, buffer.Length);
ret[ret.Length - 1] = padding;
}
m_BulkEncryption.TransformBlock(ret, 0, ret.Length, ret, 0);
message.fragment = ret;
}
message.length = (ushort)message.fragment.Length;
}
} catch (Exception e) {
throw new SslException(e, AlertDescription.InternalError, "An exception occurred");
}
// final adjustments
message.messageType = MessageType.Encrypted;
m_OutputSequenceNumber++;
} //*/
