protected internal override void Decode(IChannelHandlerContext context, IByteBuffer input, List <object> output)
{
if (!this.suppressRead && !this.handshakeFailed)
{
int writerIndex = input.WriterIndex;
Exception error = null;
try
{
bool continueLoop = true;
for (int i = 0; i < MAX_SSL_RECORDS && continueLoop; i++)
{
int readerIndex = input.ReaderIndex;
int readableBytes = writerIndex - readerIndex;
if (readableBytes < TlsUtils.SSL_RECORD_HEADER_LENGTH)
{
// Not enough data to determine the record type and length.
return;
}
int command = input.GetByte(readerIndex);
// tls, but not handshake command
switch (command)
{
case TlsUtils.SSL_CONTENT_TYPE_CHANGE_CIPHER_SPEC:
case TlsUtils.SSL_CONTENT_TYPE_ALERT:
int len = TlsUtils.GetEncryptedPacketLength(input, readerIndex);
// Not an SSL/TLS packet
if (len == TlsUtils.NOT_ENCRYPTED)
{
this.handshakeFailed = true;
var e = new NotSslRecordException(
"not an SSL/TLS record: " + ByteBufferUtil.HexDump(input));
input.SkipBytes(input.ReadableBytes);
TlsUtils.NotifyHandshakeFailure(context, e);
throw e;
}
if (len == TlsUtils.NOT_ENOUGH_DATA ||
writerIndex - readerIndex - TlsUtils.SSL_RECORD_HEADER_LENGTH < len)
{
// Not enough data
return;
}
// increase readerIndex and try again.
input.SkipBytes(len);
continue;
case TlsUtils.SSL_CONTENT_TYPE_HANDSHAKE:
int majorVersion = input.GetByte(readerIndex + 1);
// SSLv3 or TLS
if (majorVersion == 3)
{
int packetLength = input.GetUnsignedShort(readerIndex + 3) + TlsUtils.SSL_RECORD_HEADER_LENGTH;
if (readableBytes < packetLength)
{
// client hello incomplete; try again to decode once more data is ready.
return;
}
// See https://tools.ietf.org/html/rfc5246#section-7.4.1.2
//
// Decode the ssl client hello packet.
// We have to skip bytes until SessionID (which sum to 43 bytes).
//
// struct {
// ProtocolVersion client_version;
// Random random;
// SessionID session_id;
// CipherSuite cipher_suites<2..2^16-2>;
// CompressionMethod compression_methods<1..2^8-1>;
// select (extensions_present) {
// case false:
// struct {};
// case true:
// Extension extensions<0..2^16-1>;
// };
// } ClientHello;
//
int endOffset = readerIndex + packetLength;
int offset = readerIndex + 43;
if (endOffset - offset < 6)
{
continueLoop = false;
break;
}
int sessionIdLength = input.GetByte(offset);
offset += sessionIdLength + 1;
int cipherSuitesLength = input.GetUnsignedShort(offset);
offset += cipherSuitesLength + 2;
int compressionMethodLength = input.GetByte(offset);
offset += compressionMethodLength + 1;
int extensionsLength = input.GetUnsignedShort(offset);
offset += 2;
int extensionsLimit = offset + extensionsLength;
if (extensionsLimit > endOffset)
{
// Extensions should never exceed the record boundary.
continueLoop = false;
break;
}
for (;;)
{
if (extensionsLimit - offset < 4)
{
continueLoop = false;
break;
}
int extensionType = input.GetUnsignedShort(offset);
offset += 2;
int extensionLength = input.GetUnsignedShort(offset);
offset += 2;
if (extensionsLimit - offset < extensionLength)
{
continueLoop = false;
break;
}
// SNI
// See https://tools.ietf.org/html/rfc6066#page-6
if (extensionType == 0)
{
offset += 2;
if (extensionsLimit - offset < 3)
{
continueLoop = false;
break;
}
int serverNameType = input.GetByte(offset);
offset++;
if (serverNameType == 0)
{
int serverNameLength = input.GetUnsignedShort(offset);
offset += 2;
if (serverNameLength <= 0 || extensionsLimit - offset < serverNameLength)
{
continueLoop = false;
break;
}
string hostname = input.ToString(offset, serverNameLength, Encoding.UTF8);
//try
//{
// select(ctx, IDN.toASCII(hostname,
// IDN.ALLOW_UNASSIGNED).toLowerCase(Locale.US));
//}
//catch (Throwable t)
//{
// PlatformDependent.throwException(t);
//}
var idn = new IdnMapping()
{
AllowUnassigned = true
};
hostname = idn.GetAscii(hostname);
#if NETSTANDARD1_3
// TODO: netcore does not have culture sensitive tolower()
hostname = hostname.ToLowerInvariant();
#else
hostname = hostname.ToLower(new CultureInfo("en-US"));
#endif
this.Select(context, hostname);
return;
}
else
{
// invalid enum value
continueLoop = false;
break;
}
}
offset += extensionLength;
}
}
break;
// Fall-through
default:
//not tls, ssl or application data, do not try sni
continueLoop = false;
break;
}
}
}
catch (Exception e)
{
error = e;
// unexpected encoding, ignore sni and use default
if (Logger.DebugEnabled)
{
Logger.Warn($"Unexpected client hello packet: {ByteBufferUtil.HexDump(input)}", e);
}
}
if (this.serverTlsSniSettings.DefaultServerHostName != null)
{
// Just select the default server TLS setting
this.Select(context, this.serverTlsSniSettings.DefaultServerHostName);
}
else
{
this.handshakeFailed = true;
var e = new DecoderException($"failed to get the server TLS setting {error}");
TlsUtils.NotifyHandshakeFailure(context, e);
throw e;
}
}
}
protected internal override void Decode(IChannelHandlerContext context, IByteBuffer input, List <object> output)
{
int startOffset = input.ReaderIndex;
int endOffset = input.WriterIndex;
int offset = startOffset;
int totalLength = 0;
List <int> packetLengths;
// if we calculated the length of the current SSL record before, use that information.
if (this.packetLength > 0)
{
if (endOffset - startOffset < this.packetLength)
{
// input does not contain a single complete SSL record
return;
}
else
{
packetLengths = new List <int>(4)
{
this.packetLength
};
offset += this.packetLength;
totalLength = this.packetLength;
this.packetLength = 0;
}
}
else
{
packetLengths = new List <int>(4);
}
bool nonSslRecord = false;
while (totalLength < TlsUtils.MAX_ENCRYPTED_PACKET_LENGTH)
{
int readableBytes = endOffset - offset;
if (readableBytes < TlsUtils.SSL_RECORD_HEADER_LENGTH)
{
break;
}
int encryptedPacketLength = TlsUtils.GetEncryptedPacketLength(input, offset);
if (encryptedPacketLength == -1)
{
nonSslRecord = true;
break;
}
Contract.Assert(encryptedPacketLength > 0);
if (encryptedPacketLength > readableBytes)
{
// wait until the whole packet can be read
this.packetLength = encryptedPacketLength;
break;
}
int newTotalLength = totalLength + encryptedPacketLength;
if (newTotalLength > TlsUtils.MAX_ENCRYPTED_PACKET_LENGTH)
{
// Don't read too much.
break;
}
// 1. call unwrap with packet boundaries - call SslStream.ReadAsync only once.
// 2. once we're through all the whole packets, switch to reading out using fallback sized buffer
// We have a whole packet.
// Increment the offset to handle the next packet.
packetLengths.Add(encryptedPacketLength);
offset += encryptedPacketLength;
totalLength = newTotalLength;
}
if (totalLength > 0)
{
// The buffer contains one or more full SSL records.
// Slice out the whole packet so unwrap will only be called with complete packets.
// Also directly reset the packetLength. This is needed as unwrap(..) may trigger
// decode(...) again via:
// 1) unwrap(..) is called
// 2) wrap(...) is called from within unwrap(...)
// 3) wrap(...) calls unwrapLater(...)
// 4) unwrapLater(...) calls decode(...)
//
// See https://github.com/netty/netty/issues/1534
input.SkipBytes(totalLength);
this.Unwrap(context, input, startOffset, totalLength, packetLengths, output);
if (!this.firedChannelRead)
{
// Check first if firedChannelRead is not set yet as it may have been set in a
// previous decode(...) call.
this.firedChannelRead = output.Count > 0;
}
}
if (nonSslRecord)
{
// Not an SSL/TLS packet
var ex = new NotSslRecordException(
"not an SSL/TLS record: " + ByteBufferUtil.HexDump(input));
input.SkipBytes(input.ReadableBytes);
context.FireExceptionCaught(ex);
this.HandleFailure(ex);
}
}
