diff options
| -rw-r--r-- | crypto/src/crypto/tls/DtlsRecordLayer.cs | 5 | ||||
| -rw-r--r-- | crypto/src/crypto/tls/DtlsReliableHandshake.cs | 289 | ||||
| -rw-r--r-- | crypto/test/src/crypto/tls/test/DtlsTestSuite.cs | 9 | ||||
| -rw-r--r-- | crypto/test/src/crypto/tls/test/TlsTestSuite.cs | 9 |
4 files changed, 159 insertions, 153 deletions
diff --git a/crypto/src/crypto/tls/DtlsRecordLayer.cs b/crypto/src/crypto/tls/DtlsRecordLayer.cs index 3c3e1821f..39e018810 100644 --- a/crypto/src/crypto/tls/DtlsRecordLayer.cs +++ b/crypto/src/crypto/tls/DtlsRecordLayer.cs @@ -52,6 +52,11 @@ namespace Org.BouncyCastle.Crypto.Tls this.mPlaintextLimit = plaintextLimit; } + internal virtual int ReadEpoch + { + get { return mReadEpoch.Epoch; } + } + internal virtual ProtocolVersion ReadVersion { get { return mReadVersion; } diff --git a/crypto/src/crypto/tls/DtlsReliableHandshake.cs b/crypto/src/crypto/tls/DtlsReliableHandshake.cs index 18a41769a..396ea7483 100644 --- a/crypto/src/crypto/tls/DtlsReliableHandshake.cs +++ b/crypto/src/crypto/tls/DtlsReliableHandshake.cs @@ -8,7 +8,8 @@ namespace Org.BouncyCastle.Crypto.Tls { internal class DtlsReliableHandshake { - private const int MAX_RECEIVE_AHEAD = 10; + private const int MaxReceiveAhead = 16; + private const int MessageHeaderLength = 12; private readonly DtlsRecordLayer mRecordLayer; @@ -78,21 +79,7 @@ namespace Org.BouncyCastle.Crypto.Tls if (mSending) { mSending = false; - PrepareInboundFlight(); - } - - // Check if we already have the next message waiting - { - DtlsReassembler next = (DtlsReassembler)mCurrentInboundFlight[mNextReceiveSeq]; - if (next != null) - { - byte[] body = next.GetBodyIfComplete(); - if (body != null) - { - mPreviousInboundFlight = null; - return UpdateHandshakeMessagesDigest(new Message(mNextReceiveSeq++, next.MsgType, body)); - } - } + PrepareInboundFlight(Platform.CreateHashtable()); } byte[] buf = null; @@ -102,110 +89,38 @@ namespace Org.BouncyCastle.Crypto.Tls for (;;) { - int receiveLimit = mRecordLayer.GetReceiveLimit(); - if (buf == null || buf.Length < receiveLimit) - { - buf = new byte[receiveLimit]; - } - - // TODO Handle records containing multiple handshake messages - try { - for (; ; ) + for (;;) { + Message pending = GetPendingMessage(); + if (pending != null) + return pending; + + int receiveLimit = mRecordLayer.GetReceiveLimit(); + if (buf == null || buf.Length < receiveLimit) + { + buf = new byte[receiveLimit]; + } + int received = mRecordLayer.Receive(buf, 0, receiveLimit, readTimeoutMillis); if (received < 0) - { break; - } - if (received < 12) - { - continue; - } - int fragment_length = TlsUtilities.ReadUint24(buf, 9); - if (received != (fragment_length + 12)) - { - continue; - } - int seq = TlsUtilities.ReadUint16(buf, 4); - if (seq > (mNextReceiveSeq + MAX_RECEIVE_AHEAD)) - { - continue; - } - byte msg_type = TlsUtilities.ReadUint8(buf, 0); - int length = TlsUtilities.ReadUint24(buf, 1); - int fragment_offset = TlsUtilities.ReadUint24(buf, 6); - if (fragment_offset + fragment_length > length) - { - continue; - } - if (seq < mNextReceiveSeq) - { - /* - * NOTE: If we Receive the previous flight of incoming messages in full - * again, retransmit our last flight - */ - if (mPreviousInboundFlight != null) - { - DtlsReassembler reassembler = (DtlsReassembler)mPreviousInboundFlight[seq]; - if (reassembler != null) - { - reassembler.ContributeFragment(msg_type, length, buf, 12, fragment_offset, - fragment_length); - - if (CheckAll(mPreviousInboundFlight)) - { - ResendOutboundFlight(); - - /* - * TODO[DTLS] implementations SHOULD back off handshake packet - * size during the retransmit backoff. - */ - readTimeoutMillis = System.Math.Min(readTimeoutMillis * 2, 60000); - - ResetAll(mPreviousInboundFlight); - } - } - } - } - else + bool resentOutbound = ProcessRecord(MaxReceiveAhead, mRecordLayer.ReadEpoch, buf, 0, received); + if (resentOutbound) { - DtlsReassembler reassembler = (DtlsReassembler)mCurrentInboundFlight[seq]; - if (reassembler == null) - { - reassembler = new DtlsReassembler(msg_type, length); - mCurrentInboundFlight[seq] = reassembler; - } - - reassembler.ContributeFragment(msg_type, length, buf, 12, fragment_offset, fragment_length); - - if (seq == mNextReceiveSeq) - { - byte[] body = reassembler.GetBodyIfComplete(); - if (body != null) - { - mPreviousInboundFlight = null; - return UpdateHandshakeMessagesDigest(new Message(mNextReceiveSeq++, - reassembler.MsgType, body)); - } - } + readTimeoutMillis = BackOff(readTimeoutMillis); } } } - catch (IOException) + catch (IOException e) { // NOTE: Assume this is a timeout for the moment } ResendOutboundFlight(); - - /* - * TODO[DTLS] implementations SHOULD back off handshake packet size during the - * retransmit backoff. - */ - readTimeoutMillis = System.Math.Min(readTimeoutMillis * 2, 60000); + readTimeoutMillis = BackOff(readTimeoutMillis); } } @@ -216,15 +131,20 @@ namespace Org.BouncyCastle.Crypto.Tls { CheckInboundFlight(); } - else if (mCurrentInboundFlight != null) + else { - /* - * RFC 6347 4.2.4. In addition, for at least twice the default MSL defined for [TCP], - * when in the FINISHED state, the node that transmits the last flight (the server in an - * ordinary handshake or the client in a resumed handshake) MUST respond to a retransmit - * of the peer's last flight with a retransmit of the last flight. - */ - retransmit = new Retransmit(this); + PrepareInboundFlight(null); + + if (mPreviousInboundFlight != null) + { + /* + * RFC 6347 4.2.4. In addition, for at least twice the default MSL defined for [TCP], + * when in the FINISHED state, the node that transmits the last flight (the server in an + * ordinary handshake or the client in a resumed handshake) MUST respond to a retransmit + * of the peer's last flight with a retransmit of the last flight. + */ + retransmit = new Retransmit(this); + } } mRecordLayer.HandshakeSuccessful(retransmit); @@ -235,44 +155,13 @@ namespace Org.BouncyCastle.Crypto.Tls mHandshakeHash.Reset(); } - private void HandleRetransmittedHandshakeRecord(int epoch, byte[] buf, int off, int len) + private int BackOff(int timeoutMillis) { /* - * TODO Need to handle the case where the previous inbound flight contains - * messages from two epochs. + * TODO[DTLS] implementations SHOULD back off handshake packet size during the + * retransmit backoff. */ - if (len < 12) - return; - int fragment_length = TlsUtilities.ReadUint24(buf, off + 9); - if (len != (fragment_length + 12)) - return; - int seq = TlsUtilities.ReadUint16(buf, off + 4); - if (seq >= mNextReceiveSeq) - return; - - byte msg_type = TlsUtilities.ReadUint8(buf, off); - - // TODO This is a hack that only works until we try to support renegotiation - int expectedEpoch = msg_type == HandshakeType.finished ? 1 : 0; - if (epoch != expectedEpoch) - return; - - int length = TlsUtilities.ReadUint24(buf, off + 1); - int fragment_offset = TlsUtilities.ReadUint24(buf, off + 6); - if (fragment_offset + fragment_length > length) - return; - - DtlsReassembler reassembler = (DtlsReassembler)mCurrentInboundFlight[seq]; - if (reassembler != null) - { - reassembler.ContributeFragment(msg_type, length, buf, off + 12, fragment_offset, - fragment_length); - if (CheckAll(mCurrentInboundFlight)) - { - ResendOutboundFlight(); - ResetAll(mCurrentInboundFlight); - } - } + return System.Math.Min(timeoutMillis * 2, 60000); } /** @@ -289,11 +178,105 @@ namespace Org.BouncyCastle.Crypto.Tls } } - private void PrepareInboundFlight() + private Message GetPendingMessage() + { + DtlsReassembler next = (DtlsReassembler)mCurrentInboundFlight[mNextReceiveSeq]; + if (next != null) + { + byte[] body = next.GetBodyIfComplete(); + if (body != null) + { + mPreviousInboundFlight = null; + return UpdateHandshakeMessagesDigest(new Message(mNextReceiveSeq++, next.MsgType, body)); + } + } + return null; + } + + private void PrepareInboundFlight(IDictionary nextFlight) { ResetAll(mCurrentInboundFlight); mPreviousInboundFlight = mCurrentInboundFlight; - mCurrentInboundFlight = Platform.CreateHashtable(); + mCurrentInboundFlight = nextFlight; + } + + private bool ProcessRecord(int windowSize, int epoch, byte[] buf, int off, int len) + { + bool checkPreviousFlight = false; + + while (len >= MessageHeaderLength) + { + int fragment_length = TlsUtilities.ReadUint24(buf, off + 9); + int message_length = fragment_length + MessageHeaderLength; + if (len < message_length) + { + // NOTE: Truncated message - ignore it + break; + } + + int length = TlsUtilities.ReadUint24(buf, off + 1); + int fragment_offset = TlsUtilities.ReadUint24(buf, off + 6); + if (fragment_offset + fragment_length > length) + { + // NOTE: Malformed fragment - ignore it and the rest of the record + break; + } + + /* + * NOTE: This very simple epoch check will only work until we want to support + * renegotiation (and we're not likely to do that anyway). + */ + byte msg_type = TlsUtilities.ReadUint8(buf, off + 0); + int expectedEpoch = msg_type == HandshakeType.finished ? 1 : 0; + if (epoch != expectedEpoch) + { + break; + } + + int message_seq = TlsUtilities.ReadUint16(buf, off + 4); + if (message_seq >= (mNextReceiveSeq + windowSize)) + { + // NOTE: Too far ahead - ignore + } + else if (message_seq >= mNextReceiveSeq) + { + DtlsReassembler reassembler = (DtlsReassembler)mCurrentInboundFlight[message_seq]; + if (reassembler == null) + { + reassembler = new DtlsReassembler(msg_type, length); + mCurrentInboundFlight[message_seq] = reassembler; + } + + reassembler.ContributeFragment(msg_type, length, buf, off + MessageHeaderLength, fragment_offset, + fragment_length); + } + else if (mPreviousInboundFlight != null) + { + /* + * NOTE: If we receive the previous flight of incoming messages in full again, + * retransmit our last flight + */ + + DtlsReassembler reassembler = (DtlsReassembler)mPreviousInboundFlight[message_seq]; + if (reassembler != null) + { + reassembler.ContributeFragment(msg_type, length, buf, off + MessageHeaderLength, fragment_offset, + fragment_length); + checkPreviousFlight = true; + } + } + + off += message_length; + len -= message_length; + } + + bool result = checkPreviousFlight && CheckAll(mPreviousInboundFlight); + if (result) + { + ResendOutboundFlight(); + ResetAll(mPreviousInboundFlight); + } + return result; } private void ResendOutboundFlight() @@ -310,7 +293,7 @@ namespace Org.BouncyCastle.Crypto.Tls if (message.Type != HandshakeType.hello_request) { byte[] body = message.Body; - byte[] buf = new byte[12]; + byte[] buf = new byte[MessageHeaderLength]; TlsUtilities.WriteUint8(message.Type, buf, 0); TlsUtilities.WriteUint24(body.Length, buf, 1); TlsUtilities.WriteUint16(message.Seq, buf, 4); @@ -325,7 +308,7 @@ namespace Org.BouncyCastle.Crypto.Tls private void WriteMessage(Message message) { int sendLimit = mRecordLayer.GetSendLimit(); - int fragmentLimit = sendLimit - 12; + int fragmentLimit = sendLimit - MessageHeaderLength; // TODO Support a higher minimum fragment size? if (fragmentLimit < 1) @@ -349,7 +332,7 @@ namespace Org.BouncyCastle.Crypto.Tls private void WriteHandshakeFragment(Message message, int fragment_offset, int fragment_length) { - RecordLayerBuffer fragment = new RecordLayerBuffer(12 + fragment_length); + RecordLayerBuffer fragment = new RecordLayerBuffer(MessageHeaderLength + fragment_length); TlsUtilities.WriteUint8(message.Type, fragment); TlsUtilities.WriteUint24(message.Body.Length, fragment); TlsUtilities.WriteUint16(message.Seq, fragment); @@ -444,7 +427,7 @@ namespace Org.BouncyCastle.Crypto.Tls public void ReceivedHandshakeRecord(int epoch, byte[] buf, int off, int len) { - mOuter.HandleRetransmittedHandshakeRecord(epoch, buf, off, len); + mOuter.ProcessRecord(0, epoch, buf, off, len); } } } diff --git a/crypto/test/src/crypto/tls/test/DtlsTestSuite.cs b/crypto/test/src/crypto/tls/test/DtlsTestSuite.cs index a1ba62dde..f191ef005 100644 --- a/crypto/test/src/crypto/tls/test/DtlsTestSuite.cs +++ b/crypto/test/src/crypto/tls/test/DtlsTestSuite.cs @@ -215,5 +215,14 @@ namespace Org.BouncyCastle.Crypto.Tls.Tests c.serverMinimumVersion = ProtocolVersion.DTLSv10; return c; } + + public static void RunTests() + { + foreach (TestCaseData data in Suite()) + { + Console.WriteLine(data.TestName); + new DtlsTestCase().RunTest((TlsTestConfig)data.Arguments[0]); + } + } } } diff --git a/crypto/test/src/crypto/tls/test/TlsTestSuite.cs b/crypto/test/src/crypto/tls/test/TlsTestSuite.cs index 5dd9cf0f5..849e738af 100644 --- a/crypto/test/src/crypto/tls/test/TlsTestSuite.cs +++ b/crypto/test/src/crypto/tls/test/TlsTestSuite.cs @@ -201,5 +201,14 @@ namespace Org.BouncyCastle.Crypto.Tls.Tests c.serverMinimumVersion = ProtocolVersion.SSLv3; return c; } + + public static void RunTests() + { + foreach (TestCaseData data in Suite()) + { + Console.WriteLine(data.TestName); + new TlsTestCase().RunTest((TlsTestConfig)data.Arguments[0]); + } + } } } |