protected virtual void ReportServerVersion(ClientHandshakeState state, ProtocolVersion server_version)
{
TlsClientContextImpl clientContext = state.clientContext;
ProtocolVersion currentServerVersion = clientContext.ServerVersion;
if (null == currentServerVersion)
{
clientContext.SetServerVersion(server_version);
state.client.NotifyServerVersion(server_version);
}
else if (!currentServerVersion.Equals(server_version))
{
throw new TlsFatalAlert(AlertDescription.illegal_parameter);
}
}
internal virtual bool ReadRecord()
{
byte[] recordHeader = TlsUtilities.ReadAllOrNothing(TLS_HEADER_SIZE, mInput);
if (recordHeader == null)
{
return(false);
}
byte type = TlsUtilities.ReadUint8(recordHeader, TLS_HEADER_TYPE_OFFSET);
/*
* RFC 5246 6. If a TLS implementation receives an unexpected record type, it MUST send an
* unexpected_message alert.
*/
CheckType(type, AlertDescription.unexpected_message);
if (!mRestrictReadVersion)
{
int version = TlsUtilities.ReadVersionRaw(recordHeader, TLS_HEADER_VERSION_OFFSET);
if ((version & 0xffffff00) != 0x0300)
{
throw new TlsFatalAlert(AlertDescription.illegal_parameter);
}
}
else
{
ProtocolVersion version = TlsUtilities.ReadVersion(recordHeader, TLS_HEADER_VERSION_OFFSET);
if (mReadVersion == null)
{
mReadVersion = version;
}
else if (!version.Equals(mReadVersion))
{
throw new TlsFatalAlert(AlertDescription.illegal_parameter);
}
}
int length = TlsUtilities.ReadUint16(recordHeader, TLS_HEADER_LENGTH_OFFSET);
byte[] plaintext = DecodeAndVerify(type, mInput, length);
mHandler.ProcessRecord(type, plaintext, 0, plaintext.Length);
return(true);
}
protected virtual void ReceiveServerHelloMessage(MemoryStream buf)
{
{
ProtocolVersion server_version = TlsUtilities.ReadVersion(buf);
if (server_version.IsDtls)
{
throw new TlsFatalAlert(AlertDescription.illegal_parameter);
}
// Check that this matches what the server is Sending in the record layer
if (!server_version.Equals(this.mRecordStream.ReadVersion))
{
throw new TlsFatalAlert(AlertDescription.illegal_parameter);
}
ProtocolVersion client_version = Context.ClientVersion;
if (!server_version.IsEqualOrEarlierVersionOf(client_version))
{
throw new TlsFatalAlert(AlertDescription.illegal_parameter);
}
this.mRecordStream.SetWriteVersion(server_version);
ContextAdmin.SetServerVersion(server_version);
this.mTlsClient.NotifyServerVersion(server_version);
}
/*
* Read the server random
*/
this.mSecurityParameters.serverRandom = TlsUtilities.ReadFully(32, buf);
this.mSelectedSessionID = TlsUtilities.ReadOpaque8(buf);
if (this.mSelectedSessionID.Length > 32)
{
throw new TlsFatalAlert(AlertDescription.illegal_parameter);
}
this.mTlsClient.NotifySessionID(this.mSelectedSessionID);
this.mResumedSession = this.mSelectedSessionID.Length > 0 && this.mTlsSession != null &&
Arrays.AreEqual(this.mSelectedSessionID, this.mTlsSession.SessionID);
/*
* Find out which CipherSuite the server has chosen and check that it was one of the offered
* ones, and is a valid selection for the negotiated version.
*/
int selectedCipherSuite = TlsUtilities.ReadUint16(buf);
if (!Arrays.Contains(this.mOfferedCipherSuites, selectedCipherSuite) ||
selectedCipherSuite == CipherSuite.TLS_NULL_WITH_NULL_NULL ||
CipherSuite.IsScsv(selectedCipherSuite) ||
!TlsUtilities.IsValidCipherSuiteForVersion(selectedCipherSuite, Context.ServerVersion))
{
throw new TlsFatalAlert(AlertDescription.illegal_parameter);
}
this.mTlsClient.NotifySelectedCipherSuite(selectedCipherSuite);
/*
* Find out which CompressionMethod the server has chosen and check that it was one of the
* offered ones.
*/
byte selectedCompressionMethod = TlsUtilities.ReadUint8(buf);
if (!Arrays.Contains(this.mOfferedCompressionMethods, selectedCompressionMethod))
{
throw new TlsFatalAlert(AlertDescription.illegal_parameter);
}
this.mTlsClient.NotifySelectedCompressionMethod(selectedCompressionMethod);
/*
* RFC3546 2.2 The extended server hello message format MAY be sent in place of the server
* hello message when the client has requested extended functionality via the extended
* client hello message specified in Section 2.1. ... Note that the extended server hello
* message is only sent in response to an extended client hello message. This prevents the
* possibility that the extended server hello message could "break" existing TLS 1.0
* clients.
*/
this.mServerExtensions = ReadExtensions(buf);
/*
* RFC 3546 2.2 Note that the extended server hello message is only sent in response to an
* extended client hello message.
*
* However, see RFC 5746 exception below. We always include the SCSV, so an Extended Server
* Hello is always allowed.
*/
if (this.mServerExtensions != null)
{
foreach (int extType in this.mServerExtensions.Keys)
{
/*
* RFC 5746 3.6. Note that Sending a "renegotiation_info" extension in response to a
* ClientHello containing only the SCSV is an explicit exception to the prohibition
* in RFC 5246, Section 7.4.1.4, on the server Sending unsolicited extensions and is
* only allowed because the client is signaling its willingness to receive the
* extension via the TLS_EMPTY_RENEGOTIATION_INFO_SCSV SCSV.
*/
if (extType == ExtensionType.renegotiation_info)
{
continue;
}
/*
* RFC 5246 7.4.1.4 An extension type MUST NOT appear in the ServerHello unless the
* same extension type appeared in the corresponding ClientHello. If a client
* receives an extension type in ServerHello that it did not request in the
* associated ClientHello, it MUST abort the handshake with an unsupported_extension
* fatal alert.
*/
if (null == TlsUtilities.GetExtensionData(this.mClientExtensions, extType))
{
throw new TlsFatalAlert(AlertDescription.unsupported_extension);
}
/*
* RFC 3546 2.3. If [...] the older session is resumed, then the server MUST ignore
* extensions appearing in the client hello, and Send a server hello containing no
* extensions[.]
*/
if (this.mResumedSession)
{
// TODO[compat-gnutls] GnuTLS test server Sends server extensions e.g. ec_point_formats
// TODO[compat-openssl] OpenSSL test server Sends server extensions e.g. ec_point_formats
// TODO[compat-polarssl] PolarSSL test server Sends server extensions e.g. ec_point_formats
// throw new TlsFatalAlert(AlertDescription.illegal_parameter);
}
}
}
/*
* RFC 5746 3.4. Client Behavior: Initial Handshake
*/
{
/*
* When a ServerHello is received, the client MUST check if it includes the
* "renegotiation_info" extension:
*/
byte[] renegExtData = TlsUtilities.GetExtensionData(this.mServerExtensions, ExtensionType.renegotiation_info);
if (renegExtData != null)
{
/*
* If the extension is present, set the secure_renegotiation flag to TRUE. The
* client MUST then verify that the length of the "renegotiated_connection"
* field is zero, and if it is not, MUST abort the handshake (by Sending a fatal
* handshake_failure alert).
*/
this.mSecureRenegotiation = true;
if (!Arrays.ConstantTimeAreEqual(renegExtData, CreateRenegotiationInfo(TlsUtilities.EmptyBytes)))
{
throw new TlsFatalAlert(AlertDescription.handshake_failure);
}
}
}
// TODO[compat-gnutls] GnuTLS test server fails to Send renegotiation_info extension when resuming
this.mTlsClient.NotifySecureRenegotiation(this.mSecureRenegotiation);
IDictionary sessionClientExtensions = mClientExtensions, sessionServerExtensions = mServerExtensions;
if (this.mResumedSession)
{
if (selectedCipherSuite != this.mSessionParameters.CipherSuite ||
selectedCompressionMethod != this.mSessionParameters.CompressionAlgorithm)
{
throw new TlsFatalAlert(AlertDescription.illegal_parameter);
}
sessionClientExtensions = null;
sessionServerExtensions = this.mSessionParameters.ReadServerExtensions();
}
this.mSecurityParameters.cipherSuite = selectedCipherSuite;
this.mSecurityParameters.compressionAlgorithm = selectedCompressionMethod;
if (sessionServerExtensions != null)
{
{
/*
* RFC 7366 3. If a server receives an encrypt-then-MAC request extension from a client
* and then selects a stream or Authenticated Encryption with Associated Data (AEAD)
* ciphersuite, it MUST NOT send an encrypt-then-MAC response extension back to the
* client.
*/
bool serverSentEncryptThenMAC = TlsExtensionsUtilities.HasEncryptThenMacExtension(sessionServerExtensions);
if (serverSentEncryptThenMAC && !TlsUtilities.IsBlockCipherSuite(selectedCipherSuite))
{
throw new TlsFatalAlert(AlertDescription.illegal_parameter);
}
this.mSecurityParameters.encryptThenMac = serverSentEncryptThenMAC;
}
this.mSecurityParameters.extendedMasterSecret = TlsExtensionsUtilities.HasExtendedMasterSecretExtension(sessionServerExtensions);
this.mSecurityParameters.maxFragmentLength = ProcessMaxFragmentLengthExtension(sessionClientExtensions,
sessionServerExtensions, AlertDescription.illegal_parameter);
this.mSecurityParameters.truncatedHMac = TlsExtensionsUtilities.HasTruncatedHMacExtension(sessionServerExtensions);
/*
* TODO It's surprising that there's no provision to allow a 'fresh' CertificateStatus to be sent in
* a session resumption handshake.
*/
this.mAllowCertificateStatus = !this.mResumedSession &&
TlsUtilities.HasExpectedEmptyExtensionData(sessionServerExtensions, ExtensionType.status_request,
AlertDescription.illegal_parameter);
this.mExpectSessionTicket = !this.mResumedSession &&
TlsUtilities.HasExpectedEmptyExtensionData(sessionServerExtensions, ExtensionType.session_ticket,
AlertDescription.illegal_parameter);
}
/*
* TODO[session-hash]
*
* draft-ietf-tls-session-hash-04 4. Clients and servers SHOULD NOT accept handshakes
* that do not use the extended master secret [..]. (and see 5.2, 5.3)
*/
if (sessionClientExtensions != null)
{
this.mTlsClient.ProcessServerExtensions(sessionServerExtensions);
}
this.mSecurityParameters.prfAlgorithm = GetPrfAlgorithm(Context, this.mSecurityParameters.CipherSuite);
/*
* RFC 5264 7.4.9. Any cipher suite which does not explicitly specify
* verify_data_length has a verify_data_length equal to 12. This includes all
* existing cipher suites.
*/
this.mSecurityParameters.verifyDataLength = 12;
}
public virtual int Receive(byte[] buf, int off, int len, int waitMillis)
{
byte[] record = null;
for (;;)
{
int receiveLimit = System.Math.Min(len, GetReceiveLimit()) + RECORD_HEADER_LENGTH;
if (record == null || record.Length < receiveLimit)
{
record = new byte[receiveLimit];
}
try
{
if (mRetransmit != null && DateTimeUtilities.CurrentUnixMs() > mRetransmitExpiry)
{
mRetransmit = null;
mRetransmitEpoch = null;
}
int received = ReceiveRecord(record, 0, receiveLimit, waitMillis);
if (received < 0)
{
return(received);
}
if (received < RECORD_HEADER_LENGTH)
{
continue;
}
int length = TlsUtilities.ReadUint16(record, 11);
if (received != (length + RECORD_HEADER_LENGTH))
{
continue;
}
byte type = TlsUtilities.ReadUint8(record, 0);
// TODO Support user-specified custom protocols?
switch (type)
{
case ContentType.alert:
case ContentType.application_data:
case ContentType.change_cipher_spec:
case ContentType.handshake:
case ContentType.heartbeat:
break;
default:
// TODO Exception?
continue;
}
int epoch = TlsUtilities.ReadUint16(record, 3);
DtlsEpoch recordEpoch = null;
if (epoch == mReadEpoch.Epoch)
{
recordEpoch = mReadEpoch;
}
else if (type == ContentType.handshake && mRetransmitEpoch != null &&
epoch == mRetransmitEpoch.Epoch)
{
recordEpoch = mRetransmitEpoch;
}
if (recordEpoch == null)
{
continue;
}
long seq = TlsUtilities.ReadUint48(record, 5);
if (recordEpoch.ReplayWindow.ShouldDiscard(seq))
{
continue;
}
ProtocolVersion version = TlsUtilities.ReadVersion(record, 1);
if (!version.IsDtls)
{
continue;
}
if (mReadVersion != null && !mReadVersion.Equals(version))
{
continue;
}
byte[] plaintext = recordEpoch.Cipher.DecodeCiphertext(
GetMacSequenceNumber(recordEpoch.Epoch, seq), type, record, RECORD_HEADER_LENGTH,
received - RECORD_HEADER_LENGTH);
recordEpoch.ReplayWindow.ReportAuthenticated(seq);
if (plaintext.Length > this.mPlaintextLimit)
{
continue;
}
if (mReadVersion == null)
{
mReadVersion = version;
}
switch (type)
{
case ContentType.alert:
{
if (plaintext.Length == 2)
{
byte alertLevel = plaintext[0];
byte alertDescription = plaintext[1];
mPeer.NotifyAlertReceived(alertLevel, alertDescription);
if (alertLevel == AlertLevel.fatal)
{
Fail(alertDescription);
throw new TlsFatalAlert(alertDescription);
}
// TODO Can close_notify be a fatal alert?
if (alertDescription == AlertDescription.close_notify)
{
CloseTransport();
}
}
continue;
}
case ContentType.application_data:
{
if (mInHandshake)
{
// TODO Consider buffering application data for new epoch that arrives
// out-of-order with the Finished message
continue;
}
break;
}
case ContentType.change_cipher_spec:
{
// Implicitly receive change_cipher_spec and change to pending cipher state
for (int i = 0; i < plaintext.Length; ++i)
{
byte message = TlsUtilities.ReadUint8(plaintext, i);
if (message != ChangeCipherSpec.change_cipher_spec)
{
continue;
}
if (mPendingEpoch != null)
{
mReadEpoch = mPendingEpoch;
}
}
continue;
}
case ContentType.handshake:
{
if (!mInHandshake)
{
if (mRetransmit != null)
{
mRetransmit.ReceivedHandshakeRecord(epoch, plaintext, 0, plaintext.Length);
}
// TODO Consider support for HelloRequest
continue;
}
break;
}
case ContentType.heartbeat:
{
// TODO[RFC 6520]
continue;
}
}
/*
* NOTE: If we receive any non-handshake data in the new epoch implies the peer has
* received our final flight.
*/
if (!mInHandshake && mRetransmit != null)
{
this.mRetransmit = null;
this.mRetransmitEpoch = null;
}
Array.Copy(plaintext, 0, buf, off, plaintext.Length);
return(plaintext.Length);
}
catch (IOException e)
{
// NOTE: Assume this is a timeout for the moment
throw e;
}
}
}