refactor: split crypto code
This commit is contained in:
Matthias Radestock committed
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commit
519aef86fa
2 files changed
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-170
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@@ -1,32 +1,13 @@
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package router
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import (
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"crypto/rand"
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"crypto/sha256"
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"encoding/binary"
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"encoding/gob"
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"fmt"
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"io"
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"sync"
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"github.com/andybalholm/go-bit"
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"golang.org/x/crypto/nacl/box"
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"golang.org/x/crypto/nacl/secretbox"
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)
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func GenerateKeyPair() (publicKey, privateKey *[32]byte, err error) {
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return box.GenerateKey(rand.Reader)
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}
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func FormSessionKey(remotePublicKey, localPrivateKey *[32]byte, secretKey []byte) *[32]byte {
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var sharedKey [32]byte
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box.Precompute(&sharedKey, remotePublicKey, localPrivateKey)
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sharedKeySlice := sharedKey[:]
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sharedKeySlice = append(sharedKeySlice, secretKey...)
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sessionKey := sha256.Sum256(sharedKeySlice)
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return &sessionKey
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}
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// Frame Encryptors
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type Encryptor interface {
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@@ -301,154 +282,3 @@ func (di *NaClDecryptorInstance) advanceState(seqNo uint64) (int, *bit.Set) {
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return offset, di.usedOffsets
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}
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}
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// TCP Senders/Receivers
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// The lowest 64 bits of the nonce contain the message sequence
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// number. The top most bit indicates the connection polarity at the
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// sender - '1' for outbound; the next indicates protocol type - '1'
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// for TCP. The remaining 126 bits are zero. The polarity is needed so
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// that the two ends of a connection do not use the same nonces; the
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// protocol type so that the TCP and UDP sender nonces are disjoint.
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// This is a requirement of the NaCl Security Model; see
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// http://nacl.cr.yp.to/box.html.
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type TCPCryptoState struct {
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sessionKey *[32]byte
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nonce [24]byte
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seqNo uint64
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}
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func NewTCPCryptoState(sessionKey *[32]byte, outbound bool) *TCPCryptoState {
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s := &TCPCryptoState{sessionKey: sessionKey}
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if outbound {
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s.nonce[0] |= (1 << 7)
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}
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// Ensure that TCP and UDP sequences are disjoint
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s.nonce[0] |= (1 << 6)
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return s
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}
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func (s *TCPCryptoState) advance() {
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s.seqNo++
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binary.BigEndian.PutUint64(s.nonce[16:24], s.seqNo)
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}
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type TCPSender interface {
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Send([]byte) error
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}
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type GobTCPSender struct {
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encoder *gob.Encoder
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}
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type LengthPrefixTCPSender struct {
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writer io.Writer
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}
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type EncryptedTCPSender struct {
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sync.RWMutex
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sender TCPSender
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state *TCPCryptoState
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}
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func NewGobTCPSender(encoder *gob.Encoder) *GobTCPSender {
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return &GobTCPSender{encoder: encoder}
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}
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func (sender *GobTCPSender) Send(msg []byte) error {
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return sender.encoder.Encode(msg)
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}
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func NewLengthPrefixTCPSender(writer io.Writer) *LengthPrefixTCPSender {
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return &LengthPrefixTCPSender{writer: writer}
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}
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func (sender *LengthPrefixTCPSender) Send(msg []byte) error {
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l := len(msg)
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if l > MaxTCPMsgSize {
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return fmt.Errorf("outgoing message exceeds maximum size: %d > %d", l, MaxTCPMsgSize)
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}
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// We copy the message so we can send it in a single Write
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// operation, thus making this thread-safe without locking.
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prefixedMsg := make([]byte, 4+l)
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binary.BigEndian.PutUint32(prefixedMsg, uint32(l))
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copy(prefixedMsg[4:], msg)
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_, err := sender.writer.Write(prefixedMsg)
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return err
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}
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func NewEncryptedTCPSender(sender TCPSender, sessionKey *[32]byte, outbound bool) *EncryptedTCPSender {
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return &EncryptedTCPSender{sender: sender, state: NewTCPCryptoState(sessionKey, outbound)}
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}
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func (sender *EncryptedTCPSender) Send(msg []byte) error {
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sender.Lock()
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defer sender.Unlock()
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encodedMsg := secretbox.Seal(nil, msg, &sender.state.nonce, sender.state.sessionKey)
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sender.state.advance()
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return sender.sender.Send(encodedMsg)
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}
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type TCPReceiver interface {
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Receive() ([]byte, error)
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}
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type GobTCPReceiver struct {
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decoder *gob.Decoder
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}
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type LengthPrefixTCPReceiver struct {
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reader io.Reader
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}
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type EncryptedTCPReceiver struct {
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receiver TCPReceiver
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state *TCPCryptoState
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}
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func NewGobTCPReceiver(decoder *gob.Decoder) *GobTCPReceiver {
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return &GobTCPReceiver{decoder: decoder}
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}
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func (receiver *GobTCPReceiver) Receive() ([]byte, error) {
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var msg []byte
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err := receiver.decoder.Decode(&msg)
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return msg, err
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}
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func NewLengthPrefixTCPReceiver(reader io.Reader) *LengthPrefixTCPReceiver {
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return &LengthPrefixTCPReceiver{reader: reader}
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}
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func (receiver *LengthPrefixTCPReceiver) Receive() ([]byte, error) {
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lenPrefix := make([]byte, 4)
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if _, err := io.ReadFull(receiver.reader, lenPrefix); err != nil {
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return nil, err
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}
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l := binary.BigEndian.Uint32(lenPrefix)
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if l > MaxTCPMsgSize {
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return nil, fmt.Errorf("incoming message exceeds maximum size: %d > %d", l, MaxTCPMsgSize)
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}
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msg := make([]byte, l)
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_, err := io.ReadFull(receiver.reader, msg)
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return msg, err
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}
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func NewEncryptedTCPReceiver(receiver TCPReceiver, sessionKey *[32]byte, outbound bool) *EncryptedTCPReceiver {
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return &EncryptedTCPReceiver{receiver: receiver, state: NewTCPCryptoState(sessionKey, !outbound)}
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}
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func (receiver *EncryptedTCPReceiver) Receive() ([]byte, error) {
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msg, err := receiver.receiver.Receive()
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if err != nil {
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return nil, err
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}
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decodedMsg, success := secretbox.Open(nil, msg, &receiver.state.nonce, receiver.state.sessionKey)
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if !success {
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return nil, fmt.Errorf("Unable to decrypt TCP msg")
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}
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receiver.state.advance()
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return decodedMsg, nil
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}
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@@ -0,0 +1,178 @@
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package router
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import (
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"crypto/rand"
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"crypto/sha256"
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"encoding/binary"
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"encoding/gob"
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"fmt"
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"io"
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"sync"
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"golang.org/x/crypto/nacl/box"
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"golang.org/x/crypto/nacl/secretbox"
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)
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func GenerateKeyPair() (publicKey, privateKey *[32]byte, err error) {
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return box.GenerateKey(rand.Reader)
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}
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func FormSessionKey(remotePublicKey, localPrivateKey *[32]byte, secretKey []byte) *[32]byte {
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var sharedKey [32]byte
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box.Precompute(&sharedKey, remotePublicKey, localPrivateKey)
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sharedKeySlice := sharedKey[:]
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sharedKeySlice = append(sharedKeySlice, secretKey...)
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sessionKey := sha256.Sum256(sharedKeySlice)
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return &sessionKey
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}
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// TCP Senders/Receivers
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// The lowest 64 bits of the nonce contain the message sequence
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// number. The top most bit indicates the connection polarity at the
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// sender - '1' for outbound; the next indicates protocol type - '1'
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// for TCP. The remaining 126 bits are zero. The polarity is needed so
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// that the two ends of a connection do not use the same nonces; the
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// protocol type so that the TCP and UDP sender nonces are disjoint.
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// This is a requirement of the NaCl Security Model; see
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// http://nacl.cr.yp.to/box.html.
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type TCPCryptoState struct {
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sessionKey *[32]byte
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nonce [24]byte
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seqNo uint64
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}
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func NewTCPCryptoState(sessionKey *[32]byte, outbound bool) *TCPCryptoState {
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s := &TCPCryptoState{sessionKey: sessionKey}
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if outbound {
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s.nonce[0] |= (1 << 7)
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}
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// Ensure that TCP and UDP sequences are disjoint
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s.nonce[0] |= (1 << 6)
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return s
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}
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func (s *TCPCryptoState) advance() {
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s.seqNo++
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binary.BigEndian.PutUint64(s.nonce[16:24], s.seqNo)
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}
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type TCPSender interface {
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Send([]byte) error
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}
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type GobTCPSender struct {
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encoder *gob.Encoder
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}
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type LengthPrefixTCPSender struct {
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writer io.Writer
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}
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type EncryptedTCPSender struct {
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sync.RWMutex
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sender TCPSender
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state *TCPCryptoState
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}
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func NewGobTCPSender(encoder *gob.Encoder) *GobTCPSender {
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return &GobTCPSender{encoder: encoder}
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}
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func (sender *GobTCPSender) Send(msg []byte) error {
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return sender.encoder.Encode(msg)
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}
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func NewLengthPrefixTCPSender(writer io.Writer) *LengthPrefixTCPSender {
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return &LengthPrefixTCPSender{writer: writer}
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}
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func (sender *LengthPrefixTCPSender) Send(msg []byte) error {
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l := len(msg)
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if l > MaxTCPMsgSize {
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return fmt.Errorf("outgoing message exceeds maximum size: %d > %d", l, MaxTCPMsgSize)
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}
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// We copy the message so we can send it in a single Write
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// operation, thus making this thread-safe without locking.
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prefixedMsg := make([]byte, 4+l)
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binary.BigEndian.PutUint32(prefixedMsg, uint32(l))
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copy(prefixedMsg[4:], msg)
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_, err := sender.writer.Write(prefixedMsg)
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return err
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}
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func NewEncryptedTCPSender(sender TCPSender, sessionKey *[32]byte, outbound bool) *EncryptedTCPSender {
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return &EncryptedTCPSender{sender: sender, state: NewTCPCryptoState(sessionKey, outbound)}
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}
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func (sender *EncryptedTCPSender) Send(msg []byte) error {
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sender.Lock()
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defer sender.Unlock()
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encodedMsg := secretbox.Seal(nil, msg, &sender.state.nonce, sender.state.sessionKey)
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sender.state.advance()
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return sender.sender.Send(encodedMsg)
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}
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type TCPReceiver interface {
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Receive() ([]byte, error)
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}
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type GobTCPReceiver struct {
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decoder *gob.Decoder
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}
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type LengthPrefixTCPReceiver struct {
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reader io.Reader
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}
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type EncryptedTCPReceiver struct {
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receiver TCPReceiver
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state *TCPCryptoState
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}
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func NewGobTCPReceiver(decoder *gob.Decoder) *GobTCPReceiver {
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return &GobTCPReceiver{decoder: decoder}
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}
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func (receiver *GobTCPReceiver) Receive() ([]byte, error) {
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var msg []byte
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err := receiver.decoder.Decode(&msg)
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return msg, err
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}
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func NewLengthPrefixTCPReceiver(reader io.Reader) *LengthPrefixTCPReceiver {
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return &LengthPrefixTCPReceiver{reader: reader}
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}
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func (receiver *LengthPrefixTCPReceiver) Receive() ([]byte, error) {
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lenPrefix := make([]byte, 4)
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if _, err := io.ReadFull(receiver.reader, lenPrefix); err != nil {
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return nil, err
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}
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l := binary.BigEndian.Uint32(lenPrefix)
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if l > MaxTCPMsgSize {
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return nil, fmt.Errorf("incoming message exceeds maximum size: %d > %d", l, MaxTCPMsgSize)
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}
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msg := make([]byte, l)
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_, err := io.ReadFull(receiver.reader, msg)
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return msg, err
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}
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func NewEncryptedTCPReceiver(receiver TCPReceiver, sessionKey *[32]byte, outbound bool) *EncryptedTCPReceiver {
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return &EncryptedTCPReceiver{receiver: receiver, state: NewTCPCryptoState(sessionKey, !outbound)}
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}
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func (receiver *EncryptedTCPReceiver) Receive() ([]byte, error) {
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msg, err := receiver.receiver.Receive()
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if err != nil {
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return nil, err
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}
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decodedMsg, success := secretbox.Open(nil, msg, &receiver.state.nonce, receiver.state.sessionKey)
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if !success {
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return nil, fmt.Errorf("Unable to decrypt TCP msg")
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}
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receiver.state.advance()
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return decodedMsg, nil
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}
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