2019-01-02 01:55:51 +01:00
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/* SPDX-License-Identifier: MIT
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2018-05-03 15:04:00 +02:00
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*
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2019-01-02 01:55:51 +01:00
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* Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
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2018-05-03 15:04:00 +02:00
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*/
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2019-03-03 04:04:41 +01:00
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package device
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2017-06-23 13:41:59 +02:00
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import (
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"errors"
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2020-03-05 02:58:39 +01:00
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"fmt"
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2019-05-14 09:09:52 +02:00
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"sync"
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"time"
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2017-06-23 13:41:59 +02:00
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"golang.org/x/crypto/blake2s"
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"golang.org/x/crypto/chacha20poly1305"
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"golang.org/x/crypto/poly1305"
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2020-05-02 09:30:23 +02:00
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2019-02-22 20:59:43 +01:00
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"golang.zx2c4.com/wireguard/tai64n"
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2017-06-23 13:41:59 +02:00
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)
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2020-03-05 02:58:39 +01:00
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type handshakeState int
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// TODO(crawshaw): add commentary describing each state and the transitions
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2017-06-23 13:41:59 +02:00
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const (
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2020-03-05 02:58:39 +01:00
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handshakeZeroed = handshakeState(iota)
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handshakeInitiationCreated
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handshakeInitiationConsumed
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handshakeResponseCreated
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handshakeResponseConsumed
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2017-06-23 13:41:59 +02:00
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)
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2020-03-05 02:58:39 +01:00
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func (hs handshakeState) String() string {
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switch hs {
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case handshakeZeroed:
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return "handshakeZeroed"
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case handshakeInitiationCreated:
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return "handshakeInitiationCreated"
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case handshakeInitiationConsumed:
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return "handshakeInitiationConsumed"
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case handshakeResponseCreated:
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return "handshakeResponseCreated"
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case handshakeResponseConsumed:
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return "handshakeResponseConsumed"
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default:
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return fmt.Sprintf("Handshake(UNKNOWN:%d)", int(hs))
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}
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}
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2017-06-23 13:41:59 +02:00
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const (
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NoiseConstruction = "Noise_IKpsk2_25519_ChaChaPoly_BLAKE2s"
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WGIdentifier = "WireGuard v1 zx2c4 Jason@zx2c4.com"
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WGLabelMAC1 = "mac1----"
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WGLabelCookie = "cookie--"
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)
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const (
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2017-06-27 17:33:06 +02:00
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MessageInitiationType = 1
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MessageResponseType = 2
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MessageCookieReplyType = 3
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MessageTransportType = 4
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)
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const (
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2019-10-21 22:52:26 +02:00
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MessageInitiationSize = 148 // size of handshake initiation message
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2017-08-25 14:53:23 +02:00
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MessageResponseSize = 92 // size of response message
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MessageCookieReplySize = 64 // size of cookie reply message
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2019-10-21 22:52:26 +02:00
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MessageTransportHeaderSize = 16 // size of data preceding content in transport message
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2017-07-02 15:28:38 +02:00
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MessageTransportSize = MessageTransportHeaderSize + poly1305.TagSize // size of empty transport
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2017-08-25 14:53:23 +02:00
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MessageKeepaliveSize = MessageTransportSize // size of keepalive
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2019-10-21 22:52:26 +02:00
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MessageHandshakeSize = MessageInitiationSize // size of largest handshake related message
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2017-07-01 23:29:22 +02:00
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)
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const (
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MessageTransportOffsetReceiver = 4
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MessageTransportOffsetCounter = 8
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MessageTransportOffsetContent = 16
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2017-06-23 13:41:59 +02:00
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)
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2017-06-26 13:14:02 +02:00
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/* Type is an 8-bit field, followed by 3 nul bytes,
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* by marshalling the messages in little-endian byteorder
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2017-06-27 17:33:06 +02:00
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* we can treat these as a 32-bit unsigned int (for now)
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2017-06-26 13:14:02 +02:00
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*
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*/
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type MessageInitiation struct {
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2017-06-23 13:41:59 +02:00
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Type uint32
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Sender uint32
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Ephemeral NoisePublicKey
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Static [NoisePublicKeySize + poly1305.TagSize]byte
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2018-02-12 22:29:11 +01:00
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Timestamp [tai64n.TimestampSize + poly1305.TagSize]byte
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2017-07-06 16:24:24 +02:00
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MAC1 [blake2s.Size128]byte
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MAC2 [blake2s.Size128]byte
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2017-06-23 13:41:59 +02:00
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}
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type MessageResponse struct {
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Type uint32
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Sender uint32
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2017-07-01 23:29:22 +02:00
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Receiver uint32
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2017-06-23 13:41:59 +02:00
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Ephemeral NoisePublicKey
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Empty [poly1305.TagSize]byte
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2017-07-06 16:24:24 +02:00
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MAC1 [blake2s.Size128]byte
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MAC2 [blake2s.Size128]byte
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2017-06-23 13:41:59 +02:00
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}
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type MessageTransport struct {
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Type uint32
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2017-07-01 23:29:22 +02:00
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Receiver uint32
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2017-06-23 13:41:59 +02:00
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Counter uint64
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Content []byte
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}
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2017-06-27 17:33:06 +02:00
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type MessageCookieReply struct {
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Type uint32
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Receiver uint32
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2018-12-10 04:23:17 +01:00
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Nonce [chacha20poly1305.NonceSizeX]byte
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2017-06-27 17:33:06 +02:00
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Cookie [blake2s.Size128 + poly1305.TagSize]byte
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}
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2017-06-23 13:41:59 +02:00
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type Handshake struct {
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2020-03-05 02:58:39 +01:00
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state handshakeState
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2017-08-14 17:09:25 +02:00
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mutex sync.RWMutex
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hash [blake2s.Size]byte // hash value
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chainKey [blake2s.Size]byte // chain key
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presharedKey NoiseSymmetricKey // psk
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localEphemeral NoisePrivateKey // ephemeral secret key
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localIndex uint32 // used to clear hash-table
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remoteIndex uint32 // index for sending
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remoteStatic NoisePublicKey // long term key
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remoteEphemeral NoisePublicKey // ephemeral public key
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precomputedStaticStatic [NoisePublicKeySize]byte // precomputed shared secret
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2018-02-12 22:29:11 +01:00
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lastTimestamp tai64n.Timestamp
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2017-08-14 17:09:25 +02:00
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lastInitiationConsumption time.Time
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2018-05-13 23:14:43 +02:00
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lastSentHandshake time.Time
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2017-06-23 13:41:59 +02:00
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}
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var (
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2017-06-30 14:41:08 +02:00
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InitialChainKey [blake2s.Size]byte
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InitialHash [blake2s.Size]byte
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ZeroNonce [chacha20poly1305.NonceSize]byte
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2017-06-23 13:41:59 +02:00
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)
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2017-09-01 14:21:53 +02:00
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func mixKey(dst *[blake2s.Size]byte, c *[blake2s.Size]byte, data []byte) {
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KDF1(dst, c[:], data)
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2017-06-24 22:03:52 +02:00
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}
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2017-09-01 14:21:53 +02:00
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func mixHash(dst *[blake2s.Size]byte, h *[blake2s.Size]byte, data []byte) {
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2018-05-14 12:27:29 +02:00
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hash, _ := blake2s.New256(nil)
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hash.Write(h[:])
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hash.Write(data)
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hash.Sum(dst[:0])
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hash.Reset()
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2017-06-24 22:03:52 +02:00
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}
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2018-02-02 17:24:29 +01:00
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func (h *Handshake) Clear() {
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setZero(h.localEphemeral[:])
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setZero(h.remoteEphemeral[:])
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setZero(h.chainKey[:])
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setZero(h.hash[:])
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h.localIndex = 0
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2020-03-05 02:58:39 +01:00
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h.state = handshakeZeroed
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2018-02-02 17:24:29 +01:00
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}
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2017-06-26 13:14:02 +02:00
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func (h *Handshake) mixHash(data []byte) {
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2017-09-01 14:21:53 +02:00
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mixHash(&h.hash, &h.hash, data)
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2017-06-23 13:41:59 +02:00
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}
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2017-06-26 13:14:02 +02:00
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func (h *Handshake) mixKey(data []byte) {
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2017-09-01 14:21:53 +02:00
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mixKey(&h.chainKey, &h.chainKey, data)
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2017-06-23 13:41:59 +02:00
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}
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2017-06-30 14:41:08 +02:00
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/* Do basic precomputations
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*/
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func init() {
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InitialChainKey = blake2s.Sum256([]byte(NoiseConstruction))
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2017-09-01 14:21:53 +02:00
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mixHash(&InitialHash, &InitialChainKey, []byte(WGIdentifier))
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2017-06-30 14:41:08 +02:00
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}
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2017-06-26 13:14:02 +02:00
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func (device *Device) CreateMessageInitiation(peer *Peer) (*MessageInitiation, error) {
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2020-03-18 06:06:56 +01:00
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var errZeroECDHResult = errors.New("ECDH returned all zeros")
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2018-02-02 16:40:14 +01:00
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2019-01-03 19:04:00 +01:00
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device.staticIdentity.RLock()
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defer device.staticIdentity.RUnlock()
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2018-02-02 16:40:14 +01:00
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2017-06-24 15:34:17 +02:00
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handshake := &peer.handshake
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handshake.mutex.Lock()
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defer handshake.mutex.Unlock()
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2017-06-23 13:41:59 +02:00
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2017-06-24 15:34:17 +02:00
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// create ephemeral key
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2017-06-23 13:41:59 +02:00
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var err error
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2017-06-30 14:41:08 +02:00
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handshake.hash = InitialHash
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handshake.chainKey = InitialChainKey
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2017-06-24 15:34:17 +02:00
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handshake.localEphemeral, err = newPrivateKey()
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2017-06-23 13:41:59 +02:00
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if err != nil {
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return nil, err
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}
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2017-06-30 14:41:08 +02:00
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handshake.mixHash(handshake.remoteStatic[:])
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msg := MessageInitiation{
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Type: MessageInitiationType,
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Ephemeral: handshake.localEphemeral.publicKey(),
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}
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2017-06-26 13:14:02 +02:00
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handshake.mixKey(msg.Ephemeral[:])
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handshake.mixHash(msg.Ephemeral[:])
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2017-06-23 13:41:59 +02:00
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2017-06-26 13:14:02 +02:00
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// encrypt static key
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2020-03-18 06:06:56 +01:00
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ss := handshake.localEphemeral.sharedSecret(handshake.remoteStatic)
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if isZero(ss[:]) {
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return nil, errZeroECDHResult
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}
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var key [chacha20poly1305.KeySize]byte
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KDF2(
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&handshake.chainKey,
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&key,
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handshake.chainKey[:],
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ss[:],
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)
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aead, _ := chacha20poly1305.New(key[:])
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aead.Seal(msg.Static[:0], ZeroNonce[:], device.staticIdentity.publicKey[:], handshake.hash[:])
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2017-06-26 13:14:02 +02:00
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handshake.mixHash(msg.Static[:])
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2017-06-23 13:41:59 +02:00
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// encrypt timestamp
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2020-03-18 06:06:56 +01:00
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if isZero(handshake.precomputedStaticStatic[:]) {
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return nil, errZeroECDHResult
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}
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KDF2(
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&handshake.chainKey,
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&key,
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handshake.chainKey[:],
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handshake.precomputedStaticStatic[:],
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)
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2018-02-12 22:29:11 +01:00
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timestamp := tai64n.Now()
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2020-03-18 06:06:56 +01:00
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aead, _ = chacha20poly1305.New(key[:])
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aead.Seal(msg.Timestamp[:0], ZeroNonce[:], timestamp[:], handshake.hash[:])
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// assign index
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device.indexTable.Delete(handshake.localIndex)
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msg.Sender, err = device.indexTable.NewIndexForHandshake(peer, handshake)
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if err != nil {
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return nil, err
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}
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handshake.localIndex = msg.Sender
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2017-06-24 15:34:17 +02:00
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2017-06-26 13:14:02 +02:00
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handshake.mixHash(msg.Timestamp[:])
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2020-03-05 02:58:39 +01:00
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handshake.state = handshakeInitiationCreated
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2017-06-23 13:41:59 +02:00
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return &msg, nil
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}
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2017-06-26 13:14:02 +02:00
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func (device *Device) ConsumeMessageInitiation(msg *MessageInitiation) *Peer {
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2017-09-01 14:21:53 +02:00
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var (
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hash [blake2s.Size]byte
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chainKey [blake2s.Size]byte
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)
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2018-02-02 16:40:14 +01:00
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if msg.Type != MessageInitiationType {
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return nil
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}
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2019-01-03 19:04:00 +01:00
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device.staticIdentity.RLock()
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defer device.staticIdentity.RUnlock()
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2018-02-02 16:40:14 +01:00
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2018-05-13 23:14:43 +02:00
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mixHash(&hash, &InitialHash, device.staticIdentity.publicKey[:])
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2017-09-01 14:21:53 +02:00
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mixHash(&hash, &hash, msg.Ephemeral[:])
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mixKey(&chainKey, &InitialChainKey, msg.Ephemeral[:])
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2017-06-23 13:41:59 +02:00
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2017-06-26 13:14:02 +02:00
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// decrypt static key
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2017-06-24 15:34:17 +02:00
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var err error
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var peerPK NoisePublicKey
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2020-03-18 06:06:56 +01:00
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var key [chacha20poly1305.KeySize]byte
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ss := device.staticIdentity.privateKey.sharedSecret(msg.Ephemeral)
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if isZero(ss[:]) {
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return nil
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}
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KDF2(&chainKey, &key, chainKey[:], ss[:])
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aead, _ := chacha20poly1305.New(key[:])
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_, err = aead.Open(peerPK[:0], ZeroNonce[:], msg.Static[:], hash[:])
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2017-06-23 13:41:59 +02:00
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if err != nil {
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2017-06-24 15:34:17 +02:00
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return nil
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2017-06-23 13:41:59 +02:00
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}
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2017-09-01 14:21:53 +02:00
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mixHash(&hash, &hash, msg.Static[:])
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2017-06-23 13:41:59 +02:00
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2017-06-28 23:45:45 +02:00
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// lookup peer
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2017-06-24 15:34:17 +02:00
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peer := device.LookupPeer(peerPK)
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if peer == nil {
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return nil
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}
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2017-08-04 16:15:53 +02:00
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2017-06-24 15:34:17 +02:00
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handshake := &peer.handshake
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2017-06-28 23:45:45 +02:00
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// verify identity
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2017-06-24 15:34:17 +02:00
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2018-02-12 22:29:11 +01:00
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var timestamp tai64n.Timestamp
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2017-06-28 23:45:45 +02:00
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2017-08-14 17:09:25 +02:00
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handshake.mutex.RLock()
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2020-03-18 06:06:56 +01:00
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if isZero(handshake.precomputedStaticStatic[:]) {
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handshake.mutex.RUnlock()
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return nil
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}
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2017-09-01 14:21:53 +02:00
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|
|
KDF2(
|
|
|
|
&chainKey,
|
|
|
|
&key,
|
2017-08-14 17:09:25 +02:00
|
|
|
chainKey[:],
|
|
|
|
handshake.precomputedStaticStatic[:],
|
|
|
|
)
|
2020-03-18 06:06:56 +01:00
|
|
|
aead, _ = chacha20poly1305.New(key[:])
|
2017-08-14 17:09:25 +02:00
|
|
|
_, err = aead.Open(timestamp[:0], ZeroNonce[:], msg.Timestamp[:], hash[:])
|
|
|
|
if err != nil {
|
|
|
|
handshake.mutex.RUnlock()
|
|
|
|
return nil
|
|
|
|
}
|
2017-09-01 14:21:53 +02:00
|
|
|
mixHash(&hash, &hash, msg.Timestamp[:])
|
2017-06-28 23:45:45 +02:00
|
|
|
|
2017-08-14 17:09:25 +02:00
|
|
|
// protect against replay & flood
|
2017-06-28 23:45:45 +02:00
|
|
|
|
2019-10-16 04:39:44 +02:00
|
|
|
replay := !timestamp.After(handshake.lastTimestamp)
|
|
|
|
flood := time.Since(handshake.lastInitiationConsumption) <= HandshakeInitationRate
|
2017-08-14 17:09:25 +02:00
|
|
|
handshake.mutex.RUnlock()
|
2019-10-16 04:39:44 +02:00
|
|
|
if replay {
|
|
|
|
device.log.Debug.Printf("%v - ConsumeMessageInitiation: handshake replay @ %v\n", peer, timestamp)
|
|
|
|
return nil
|
|
|
|
}
|
|
|
|
if flood {
|
|
|
|
device.log.Debug.Printf("%v - ConsumeMessageInitiation: handshake flood\n", peer)
|
2017-06-24 15:34:17 +02:00
|
|
|
return nil
|
|
|
|
}
|
|
|
|
|
|
|
|
// update handshake state
|
2017-06-23 13:41:59 +02:00
|
|
|
|
2017-06-28 23:45:45 +02:00
|
|
|
handshake.mutex.Lock()
|
|
|
|
|
2017-06-24 15:34:17 +02:00
|
|
|
handshake.hash = hash
|
|
|
|
handshake.chainKey = chainKey
|
|
|
|
handshake.remoteIndex = msg.Sender
|
|
|
|
handshake.remoteEphemeral = msg.Ephemeral
|
2019-10-17 15:43:06 +02:00
|
|
|
if timestamp.After(handshake.lastTimestamp) {
|
|
|
|
handshake.lastTimestamp = timestamp
|
|
|
|
}
|
|
|
|
now := time.Now()
|
|
|
|
if now.After(handshake.lastInitiationConsumption) {
|
|
|
|
handshake.lastInitiationConsumption = now
|
|
|
|
}
|
2020-03-05 02:58:39 +01:00
|
|
|
handshake.state = handshakeInitiationConsumed
|
2017-06-28 23:45:45 +02:00
|
|
|
|
|
|
|
handshake.mutex.Unlock()
|
|
|
|
|
2018-05-13 19:50:58 +02:00
|
|
|
setZero(hash[:])
|
|
|
|
setZero(chainKey[:])
|
|
|
|
|
2017-06-24 15:34:17 +02:00
|
|
|
return peer
|
2017-06-23 13:41:59 +02:00
|
|
|
}
|
|
|
|
|
2017-06-24 15:34:17 +02:00
|
|
|
func (device *Device) CreateMessageResponse(peer *Peer) (*MessageResponse, error) {
|
|
|
|
handshake := &peer.handshake
|
|
|
|
handshake.mutex.Lock()
|
|
|
|
defer handshake.mutex.Unlock()
|
|
|
|
|
2020-03-05 02:58:39 +01:00
|
|
|
if handshake.state != handshakeInitiationConsumed {
|
2018-05-13 18:23:40 +02:00
|
|
|
return nil, errors.New("handshake initiation must be consumed first")
|
2017-06-24 15:34:17 +02:00
|
|
|
}
|
|
|
|
|
|
|
|
// assign index
|
|
|
|
|
|
|
|
var err error
|
2018-05-13 18:23:40 +02:00
|
|
|
device.indexTable.Delete(handshake.localIndex)
|
|
|
|
handshake.localIndex, err = device.indexTable.NewIndexForHandshake(peer, handshake)
|
2017-06-24 15:34:17 +02:00
|
|
|
if err != nil {
|
|
|
|
return nil, err
|
|
|
|
}
|
2017-06-23 13:41:59 +02:00
|
|
|
|
2017-06-24 22:03:52 +02:00
|
|
|
var msg MessageResponse
|
|
|
|
msg.Type = MessageResponseType
|
|
|
|
msg.Sender = handshake.localIndex
|
2017-07-01 23:29:22 +02:00
|
|
|
msg.Receiver = handshake.remoteIndex
|
2017-06-24 22:03:52 +02:00
|
|
|
|
2017-06-24 15:34:17 +02:00
|
|
|
// create ephemeral key
|
|
|
|
|
|
|
|
handshake.localEphemeral, err = newPrivateKey()
|
|
|
|
if err != nil {
|
|
|
|
return nil, err
|
|
|
|
}
|
|
|
|
msg.Ephemeral = handshake.localEphemeral.publicKey()
|
2017-06-26 13:14:02 +02:00
|
|
|
handshake.mixHash(msg.Ephemeral[:])
|
2017-07-01 23:29:22 +02:00
|
|
|
handshake.mixKey(msg.Ephemeral[:])
|
2017-06-24 15:34:17 +02:00
|
|
|
|
|
|
|
func() {
|
|
|
|
ss := handshake.localEphemeral.sharedSecret(handshake.remoteEphemeral)
|
2017-06-26 13:14:02 +02:00
|
|
|
handshake.mixKey(ss[:])
|
2017-06-24 15:34:17 +02:00
|
|
|
ss = handshake.localEphemeral.sharedSecret(handshake.remoteStatic)
|
2017-06-26 13:14:02 +02:00
|
|
|
handshake.mixKey(ss[:])
|
2017-06-24 15:34:17 +02:00
|
|
|
}()
|
|
|
|
|
2018-05-13 19:50:58 +02:00
|
|
|
// add preshared key
|
2017-06-24 15:34:17 +02:00
|
|
|
|
|
|
|
var tau [blake2s.Size]byte
|
|
|
|
var key [chacha20poly1305.KeySize]byte
|
2017-09-01 14:21:53 +02:00
|
|
|
|
|
|
|
KDF3(
|
|
|
|
&handshake.chainKey,
|
|
|
|
&tau,
|
|
|
|
&key,
|
|
|
|
handshake.chainKey[:],
|
|
|
|
handshake.presharedKey[:],
|
|
|
|
)
|
|
|
|
|
2017-06-26 13:14:02 +02:00
|
|
|
handshake.mixHash(tau[:])
|
2017-06-24 15:34:17 +02:00
|
|
|
|
|
|
|
func() {
|
|
|
|
aead, _ := chacha20poly1305.New(key[:])
|
2017-06-24 22:03:52 +02:00
|
|
|
aead.Seal(msg.Empty[:0], ZeroNonce[:], nil, handshake.hash[:])
|
2017-06-26 13:14:02 +02:00
|
|
|
handshake.mixHash(msg.Empty[:])
|
2017-06-24 15:34:17 +02:00
|
|
|
}()
|
|
|
|
|
2020-03-05 02:58:39 +01:00
|
|
|
handshake.state = handshakeResponseCreated
|
2017-09-01 14:21:53 +02:00
|
|
|
|
2017-06-24 15:34:17 +02:00
|
|
|
return &msg, nil
|
2017-06-23 13:41:59 +02:00
|
|
|
}
|
2017-06-24 22:03:52 +02:00
|
|
|
|
|
|
|
func (device *Device) ConsumeMessageResponse(msg *MessageResponse) *Peer {
|
|
|
|
if msg.Type != MessageResponseType {
|
2017-06-26 13:14:02 +02:00
|
|
|
return nil
|
2017-06-24 22:03:52 +02:00
|
|
|
}
|
|
|
|
|
2018-05-13 18:23:40 +02:00
|
|
|
// lookup handshake by receiver
|
2017-06-24 22:03:52 +02:00
|
|
|
|
2018-05-13 18:23:40 +02:00
|
|
|
lookup := device.indexTable.Lookup(msg.Receiver)
|
2017-06-26 22:07:29 +02:00
|
|
|
handshake := lookup.handshake
|
|
|
|
if handshake == nil {
|
2017-06-24 22:03:52 +02:00
|
|
|
return nil
|
|
|
|
}
|
2017-06-26 22:07:29 +02:00
|
|
|
|
2017-06-28 23:45:45 +02:00
|
|
|
var (
|
|
|
|
hash [blake2s.Size]byte
|
|
|
|
chainKey [blake2s.Size]byte
|
|
|
|
)
|
2017-06-24 22:03:52 +02:00
|
|
|
|
2017-06-28 23:45:45 +02:00
|
|
|
ok := func() bool {
|
2017-06-24 22:03:52 +02:00
|
|
|
|
2018-02-02 17:24:29 +01:00
|
|
|
// lock handshake state
|
2017-06-24 22:03:52 +02:00
|
|
|
|
2017-06-28 23:45:45 +02:00
|
|
|
handshake.mutex.RLock()
|
|
|
|
defer handshake.mutex.RUnlock()
|
2017-06-24 22:03:52 +02:00
|
|
|
|
2020-03-05 02:58:39 +01:00
|
|
|
if handshake.state != handshakeInitiationCreated {
|
2017-06-28 23:45:45 +02:00
|
|
|
return false
|
|
|
|
}
|
2017-06-24 22:03:52 +02:00
|
|
|
|
2018-02-02 17:24:29 +01:00
|
|
|
// lock private key for reading
|
|
|
|
|
2019-01-03 19:04:00 +01:00
|
|
|
device.staticIdentity.RLock()
|
|
|
|
defer device.staticIdentity.RUnlock()
|
2018-02-02 17:24:29 +01:00
|
|
|
|
2017-06-28 23:45:45 +02:00
|
|
|
// finish 3-way DH
|
2017-06-24 22:03:52 +02:00
|
|
|
|
2017-09-01 14:21:53 +02:00
|
|
|
mixHash(&hash, &handshake.hash, msg.Ephemeral[:])
|
|
|
|
mixKey(&chainKey, &handshake.chainKey, msg.Ephemeral[:])
|
2017-06-24 22:03:52 +02:00
|
|
|
|
2017-06-28 23:45:45 +02:00
|
|
|
func() {
|
|
|
|
ss := handshake.localEphemeral.sharedSecret(msg.Ephemeral)
|
2017-09-01 14:21:53 +02:00
|
|
|
mixKey(&chainKey, &chainKey, ss[:])
|
|
|
|
setZero(ss[:])
|
|
|
|
}()
|
|
|
|
|
|
|
|
func() {
|
2018-05-13 23:14:43 +02:00
|
|
|
ss := device.staticIdentity.privateKey.sharedSecret(msg.Ephemeral)
|
2017-09-01 14:21:53 +02:00
|
|
|
mixKey(&chainKey, &chainKey, ss[:])
|
|
|
|
setZero(ss[:])
|
2017-06-28 23:45:45 +02:00
|
|
|
}()
|
|
|
|
|
|
|
|
// add preshared key (psk)
|
|
|
|
|
|
|
|
var tau [blake2s.Size]byte
|
|
|
|
var key [chacha20poly1305.KeySize]byte
|
2017-09-01 14:21:53 +02:00
|
|
|
KDF3(
|
|
|
|
&chainKey,
|
|
|
|
&tau,
|
|
|
|
&key,
|
|
|
|
chainKey[:],
|
|
|
|
handshake.presharedKey[:],
|
|
|
|
)
|
|
|
|
mixHash(&hash, &hash, tau[:])
|
2017-06-28 23:45:45 +02:00
|
|
|
|
2018-02-02 17:24:29 +01:00
|
|
|
// authenticate transcript
|
2017-06-28 23:45:45 +02:00
|
|
|
|
|
|
|
aead, _ := chacha20poly1305.New(key[:])
|
|
|
|
_, err := aead.Open(nil, ZeroNonce[:], msg.Empty[:], hash[:])
|
|
|
|
if err != nil {
|
|
|
|
return false
|
|
|
|
}
|
2017-09-01 14:21:53 +02:00
|
|
|
mixHash(&hash, &hash, msg.Empty[:])
|
2017-06-28 23:45:45 +02:00
|
|
|
return true
|
|
|
|
}()
|
|
|
|
|
|
|
|
if !ok {
|
2017-06-24 22:03:52 +02:00
|
|
|
return nil
|
|
|
|
}
|
|
|
|
|
|
|
|
// update handshake state
|
|
|
|
|
2017-06-28 23:45:45 +02:00
|
|
|
handshake.mutex.Lock()
|
|
|
|
|
2017-06-24 22:03:52 +02:00
|
|
|
handshake.hash = hash
|
|
|
|
handshake.chainKey = chainKey
|
|
|
|
handshake.remoteIndex = msg.Sender
|
2020-03-05 02:58:39 +01:00
|
|
|
handshake.state = handshakeResponseConsumed
|
2017-06-24 22:03:52 +02:00
|
|
|
|
2017-06-28 23:45:45 +02:00
|
|
|
handshake.mutex.Unlock()
|
|
|
|
|
2017-09-01 14:21:53 +02:00
|
|
|
setZero(hash[:])
|
|
|
|
setZero(chainKey[:])
|
|
|
|
|
2017-06-26 22:07:29 +02:00
|
|
|
return lookup.peer
|
2017-06-24 22:03:52 +02:00
|
|
|
}
|
|
|
|
|
2018-05-13 19:50:58 +02:00
|
|
|
/* Derives a new keypair from the current handshake state
|
2017-07-10 12:09:19 +02:00
|
|
|
*
|
|
|
|
*/
|
2018-05-13 23:14:43 +02:00
|
|
|
func (peer *Peer) BeginSymmetricSession() error {
|
2017-09-01 14:21:53 +02:00
|
|
|
device := peer.device
|
2017-06-24 22:03:52 +02:00
|
|
|
handshake := &peer.handshake
|
|
|
|
handshake.mutex.Lock()
|
|
|
|
defer handshake.mutex.Unlock()
|
|
|
|
|
|
|
|
// derive keys
|
|
|
|
|
2017-06-26 22:07:29 +02:00
|
|
|
var isInitiator bool
|
2017-06-24 22:03:52 +02:00
|
|
|
var sendKey [chacha20poly1305.KeySize]byte
|
|
|
|
var recvKey [chacha20poly1305.KeySize]byte
|
|
|
|
|
2020-03-05 02:58:39 +01:00
|
|
|
if handshake.state == handshakeResponseConsumed {
|
2017-09-01 14:21:53 +02:00
|
|
|
KDF2(
|
|
|
|
&sendKey,
|
|
|
|
&recvKey,
|
|
|
|
handshake.chainKey[:],
|
|
|
|
nil,
|
|
|
|
)
|
2017-06-26 22:07:29 +02:00
|
|
|
isInitiator = true
|
2020-03-05 02:58:39 +01:00
|
|
|
} else if handshake.state == handshakeResponseCreated {
|
2017-09-01 14:21:53 +02:00
|
|
|
KDF2(
|
|
|
|
&recvKey,
|
|
|
|
&sendKey,
|
|
|
|
handshake.chainKey[:],
|
|
|
|
nil,
|
|
|
|
)
|
2017-06-26 22:07:29 +02:00
|
|
|
isInitiator = false
|
2017-06-24 22:03:52 +02:00
|
|
|
} else {
|
2020-03-05 02:58:39 +01:00
|
|
|
return fmt.Errorf("invalid state for keypair derivation: %v", handshake.state)
|
2017-06-24 22:03:52 +02:00
|
|
|
}
|
|
|
|
|
2017-06-30 14:41:08 +02:00
|
|
|
// zero handshake
|
|
|
|
|
2017-09-01 14:21:53 +02:00
|
|
|
setZero(handshake.chainKey[:])
|
2018-05-13 19:50:58 +02:00
|
|
|
setZero(handshake.hash[:]) // Doesn't necessarily need to be zeroed. Could be used for something interesting down the line.
|
2017-09-01 14:21:53 +02:00
|
|
|
setZero(handshake.localEphemeral[:])
|
2020-03-05 02:58:39 +01:00
|
|
|
peer.handshake.state = handshakeZeroed
|
2017-06-24 22:03:52 +02:00
|
|
|
|
2017-06-30 14:41:08 +02:00
|
|
|
// create AEAD instances
|
2017-06-26 22:07:29 +02:00
|
|
|
|
2018-05-13 18:23:40 +02:00
|
|
|
keypair := new(Keypair)
|
|
|
|
keypair.send, _ = chacha20poly1305.New(sendKey[:])
|
|
|
|
keypair.receive, _ = chacha20poly1305.New(recvKey[:])
|
2017-09-01 14:21:53 +02:00
|
|
|
|
|
|
|
setZero(sendKey[:])
|
|
|
|
setZero(recvKey[:])
|
|
|
|
|
2018-05-13 18:23:40 +02:00
|
|
|
keypair.created = time.Now()
|
|
|
|
keypair.sendNonce = 0
|
|
|
|
keypair.replayFilter.Init()
|
|
|
|
keypair.isInitiator = isInitiator
|
|
|
|
keypair.localIndex = peer.handshake.localIndex
|
|
|
|
keypair.remoteIndex = peer.handshake.remoteIndex
|
2017-06-24 22:03:52 +02:00
|
|
|
|
2017-06-26 22:07:29 +02:00
|
|
|
// remap index
|
|
|
|
|
2018-05-13 18:23:40 +02:00
|
|
|
device.indexTable.SwapIndexForKeypair(handshake.localIndex, keypair)
|
2017-06-26 22:07:29 +02:00
|
|
|
handshake.localIndex = 0
|
|
|
|
|
|
|
|
// rotate key pairs
|
|
|
|
|
2018-05-13 23:14:43 +02:00
|
|
|
keypairs := &peer.keypairs
|
2019-01-03 19:04:00 +01:00
|
|
|
keypairs.Lock()
|
|
|
|
defer keypairs.Unlock()
|
2017-08-14 17:09:25 +02:00
|
|
|
|
2018-05-13 23:14:43 +02:00
|
|
|
previous := keypairs.previous
|
2020-05-02 09:30:23 +02:00
|
|
|
next := keypairs.loadNext()
|
2018-05-13 23:14:43 +02:00
|
|
|
current := keypairs.current
|
2017-09-20 09:26:08 +02:00
|
|
|
|
2018-05-07 22:27:03 +02:00
|
|
|
if isInitiator {
|
|
|
|
if next != nil {
|
2020-05-02 09:30:23 +02:00
|
|
|
keypairs.storeNext(nil)
|
2018-05-13 23:14:43 +02:00
|
|
|
keypairs.previous = next
|
2018-05-07 22:27:03 +02:00
|
|
|
device.DeleteKeypair(current)
|
2017-09-20 09:26:08 +02:00
|
|
|
} else {
|
2018-05-13 23:14:43 +02:00
|
|
|
keypairs.previous = current
|
2017-06-26 22:07:29 +02:00
|
|
|
}
|
2018-05-07 22:27:03 +02:00
|
|
|
device.DeleteKeypair(previous)
|
2018-05-13 23:14:43 +02:00
|
|
|
keypairs.current = keypair
|
2017-09-20 09:26:08 +02:00
|
|
|
} else {
|
2020-05-02 09:30:23 +02:00
|
|
|
keypairs.storeNext(keypair)
|
2018-05-07 22:27:03 +02:00
|
|
|
device.DeleteKeypair(next)
|
2018-05-13 23:14:43 +02:00
|
|
|
keypairs.previous = nil
|
2018-05-07 22:27:03 +02:00
|
|
|
device.DeleteKeypair(previous)
|
2017-09-20 09:26:08 +02:00
|
|
|
}
|
2017-06-26 22:07:29 +02:00
|
|
|
|
2018-05-13 19:50:58 +02:00
|
|
|
return nil
|
|
|
|
}
|
|
|
|
|
|
|
|
func (peer *Peer) ReceivedWithKeypair(receivedKeypair *Keypair) bool {
|
2018-05-13 23:14:43 +02:00
|
|
|
keypairs := &peer.keypairs
|
2020-05-02 09:30:23 +02:00
|
|
|
|
|
|
|
if keypairs.loadNext() != receivedKeypair {
|
2018-05-13 19:50:58 +02:00
|
|
|
return false
|
|
|
|
}
|
2019-01-03 19:04:00 +01:00
|
|
|
keypairs.Lock()
|
|
|
|
defer keypairs.Unlock()
|
2020-05-02 09:30:23 +02:00
|
|
|
if keypairs.loadNext() != receivedKeypair {
|
2018-05-13 19:50:58 +02:00
|
|
|
return false
|
|
|
|
}
|
2018-05-13 23:14:43 +02:00
|
|
|
old := keypairs.previous
|
|
|
|
keypairs.previous = keypairs.current
|
2018-05-13 19:50:58 +02:00
|
|
|
peer.device.DeleteKeypair(old)
|
2020-05-02 09:30:23 +02:00
|
|
|
keypairs.current = keypairs.loadNext()
|
|
|
|
keypairs.storeNext(nil)
|
2018-05-13 19:50:58 +02:00
|
|
|
return true
|
2017-06-24 22:03:52 +02:00
|
|
|
}
|