uquic/crypto_stream.go
Marten Seemann 387c28d707 when the encryption level changes, reject data on that crypto stream
There are two checks that need to be performed:
1. the crypto stream must not have any more data queued for reading
2. when receiving CRYPTO frames for that crypto stream afterwards, they
must not exceed the highest offset received on that stream
2018-10-26 17:09:52 +07:00

108 lines
2.7 KiB
Go

package quic
import (
"errors"
"fmt"
"io"
"github.com/lucas-clemente/quic-go/internal/protocol"
"github.com/lucas-clemente/quic-go/internal/utils"
"github.com/lucas-clemente/quic-go/internal/wire"
)
type cryptoStream interface {
// for receiving data
HandleCryptoFrame(*wire.CryptoFrame) error
GetCryptoData() []byte
Finish() error
// for sending data
io.Writer
HasData() bool
PopCryptoFrame(protocol.ByteCount) *wire.CryptoFrame
}
type cryptoStreamImpl struct {
queue *frameSorter
msgBuf []byte
highestOffset protocol.ByteCount
finished bool
writeOffset protocol.ByteCount
writeBuf []byte
}
func newCryptoStream() cryptoStream {
return &cryptoStreamImpl{
queue: newFrameSorter(),
}
}
func (s *cryptoStreamImpl) HandleCryptoFrame(f *wire.CryptoFrame) error {
highestOffset := f.Offset + protocol.ByteCount(len(f.Data))
if maxOffset := highestOffset; maxOffset > protocol.MaxCryptoStreamOffset {
return fmt.Errorf("received invalid offset %d on crypto stream, maximum allowed %d", maxOffset, protocol.MaxCryptoStreamOffset)
}
if s.finished {
if highestOffset > s.highestOffset {
// reject crypto data received after this stream was already finished
return errors.New("received crypto data after change of encryption level")
}
// ignore data with a smaller offset than the highest received
// could e.g. be a retransmission
return nil
}
s.highestOffset = utils.MaxByteCount(s.highestOffset, highestOffset)
if err := s.queue.Push(f.Data, f.Offset, false); err != nil {
return err
}
for {
data, _ := s.queue.Pop()
if data == nil {
return nil
}
s.msgBuf = append(s.msgBuf, data...)
}
}
// GetCryptoData retrieves data that was received in CRYPTO frames
func (s *cryptoStreamImpl) GetCryptoData() []byte {
if len(s.msgBuf) < 4 {
return nil
}
msgLen := 4 + int(s.msgBuf[1])<<16 + int(s.msgBuf[2])<<8 + int(s.msgBuf[3])
if len(s.msgBuf) < msgLen {
return nil
}
msg := make([]byte, msgLen)
copy(msg, s.msgBuf[:msgLen])
s.msgBuf = s.msgBuf[msgLen:]
return msg
}
func (s *cryptoStreamImpl) Finish() error {
if s.queue.HasMoreData() {
return errors.New("encryption level changed, but crypto stream has more data to read")
}
s.finished = true
return nil
}
// Writes writes data that should be sent out in CRYPTO frames
func (s *cryptoStreamImpl) Write(p []byte) (int, error) {
s.writeBuf = append(s.writeBuf, p...)
return len(p), nil
}
func (s *cryptoStreamImpl) HasData() bool {
return len(s.writeBuf) > 0
}
func (s *cryptoStreamImpl) PopCryptoFrame(maxLen protocol.ByteCount) *wire.CryptoFrame {
f := &wire.CryptoFrame{Offset: s.writeOffset}
n := utils.MinByteCount(f.MaxDataLen(maxLen), protocol.ByteCount(len(s.writeBuf)))
f.Data = s.writeBuf[:n]
s.writeBuf = s.writeBuf[n:]
s.writeOffset += n
return f
}