/*
GoVPN -- simple secure free software virtual private network daemon
-Copyright (C) 2014-2016 Sergey Matveev <stargrave@stargrave.org>
+Copyright (C) 2014-2017 Sergey Matveev <stargrave@stargrave.org>
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
"crypto/subtle"
"encoding/binary"
"io"
- "log"
"time"
+ "chacha20"
+ "github.com/Sirupsen/logrus"
"github.com/agl/ed25519"
"github.com/agl/ed25519/extra25519"
+ "github.com/pkg/errors"
"golang.org/x/crypto/blake2b"
"golang.org/x/crypto/curve25519"
- "golang.org/x/crypto/salsa20"
)
const (
+ // RSize is size in bytes of channel binding random value
RSize = 8
+ // SSize is size in bytes of shared secret half
SSize = 32
+
+ wrapIDTag = "idTag id:%q timeSync:%d"
)
+// Handshake is state of a handshake/negotiation between client and server
type Handshake struct {
addr string
conn io.Writer
Conf *PeerConf
dsaPubH *[ed25519.PublicKeySize]byte
key *[32]byte
- rNonce *[RSize]byte
+ rNonce *[16]byte
dhPriv *[32]byte // own private DH key
rServer *[RSize]byte // random string for authentication
rClient *[RSize]byte
sClient *[SSize]byte
}
+// LogFields return a logrus compatible logging context
+func (h *Handshake) LogFields() logrus.Fields {
+ const prefix = "hs_"
+ return logrus.Fields{
+ prefix + "remote": h.addr,
+ prefix + "last_ping": h.LastPing.String(),
+ prefix + "id": h.Conf.ID.String(),
+ }
+}
+
func keyFromSecrets(server, client []byte) *[SSize]byte {
k := new([SSize]byte)
for i := 0; i < SSize; i++ {
}
}
-func (h *Handshake) rNonceNext(count uint64) []byte {
- nonce := make([]byte, RSize)
- nonceCurrent, _ := binary.Uvarint(h.rNonce[:])
- binary.PutUvarint(nonce, nonceCurrent+count)
+func (h *Handshake) rNonceNext(count uint64) *[16]byte {
+ nonce := new([16]byte)
+ nonceCurrent, _ := binary.Uvarint(h.rNonce[8:])
+ binary.PutUvarint(nonce[8:], nonceCurrent+count)
return nonce
}
-func dhKeypairGen() (*[32]byte, *[32]byte) {
+func dhKeypairGen() (*[32]byte, *[32]byte, error) {
priv := new([32]byte)
pub := new([32]byte)
repr := new([32]byte)
reprFound := false
for !reprFound {
if _, err := io.ReadFull(Rand, priv[:]); err != nil {
- log.Fatalln("Error reading random for DH private key:", err)
+ return nil, nil, errors.Wrapf(err, wrapIoReadFull, "Rand")
}
reprFound = extra25519.ScalarBaseMult(pub, repr, priv)
}
- return priv, repr
+ return priv, repr, nil
}
func dhKeyGen(priv, pub *[32]byte) *[32]byte {
return &hashed
}
-// Create new handshake state.
+// NewHandshake creates new handshake state.
func NewHandshake(addr string, conn io.Writer, conf *PeerConf) *Handshake {
state := Handshake{
addr: addr,
}
// Generate ID tag from client identification and data.
-func idTag(id *PeerId, timeSync int, data []byte) []byte {
+func idTag(id *PeerID, timeSync int, data []byte) ([]byte, error) {
enc := make([]byte, 8)
copy(enc, data)
AddTimeSync(timeSync, enc)
mac, err := blake2b.New256(id[:])
if err != nil {
- panic(err)
+ return nil, errors.Wrap(err, wrapBlake2bNew256)
}
- mac.Write(enc)
- mac.Sum(enc[:0])
- return enc
+ if _, err = mac.Write(enc); err != nil {
+ return nil, errors.Wrap(err, "mac.Write")
+ }
+ sum := mac.Sum(nil)
+ return sum[len(sum)-8:], nil
}
-// Start handshake's procedure from the client. It is the entry point
-// for starting the handshake procedure. // First handshake packet
-// will be sent immediately.
-func HandshakeStart(addr string, conn io.Writer, conf *PeerConf) *Handshake {
+// HandshakeStarts starts handshake's procedure from the client.
+// It is the entry point for starting the handshake procedure.
+// First handshake packet will be sent immediately.
+func HandshakeStart(addr string, conn io.Writer, conf *PeerConf) (*Handshake, error) {
state := NewHandshake(addr, conn, conf)
var dhPubRepr *[32]byte
- state.dhPriv, dhPubRepr = dhKeypairGen()
+ var err error
+ if state.dhPriv, dhPubRepr, err = dhKeypairGen(); err != nil {
+ return nil, errors.Wrap(err, "dhKeypairGen")
+ }
- state.rNonce = new([RSize]byte)
- if _, err := io.ReadFull(Rand, state.rNonce[:]); err != nil {
- log.Fatalln("Error reading random for nonce:", err)
+ state.rNonce = new([16]byte)
+ if _, err := io.ReadFull(Rand, state.rNonce[8:]); err != nil {
+ return nil, errors.Wrapf(err, wrapIoReadFull, "Rand")
}
var enc []byte
if conf.Noise {
}
copy(enc, dhPubRepr[:])
if conf.Encless {
- var err error
- enc, err = EnclessEncode(state.dsaPubH, state.rNonce[:], enc)
+ enc, err = EnclessEncode(state.dsaPubH, state.rNonce, enc)
if err != err {
- panic(err)
+ return nil, errors.Wrap(err, wrapEnclessDecode)
}
} else {
- salsa20.XORKeyStream(enc, enc, state.rNonce[:], state.dsaPubH)
+ chacha20.XORKeyStream(enc, enc, state.rNonce, state.dsaPubH)
+ }
+ tag, err := idTag(state.Conf.ID, state.Conf.TimeSync, state.rNonce[8:])
+ if err != nil {
+ return nil, errors.Wrapf(err, wrapIDTag, state.Conf.ID.String(), state.Conf.TimeSync)
+ }
+ data := append(state.rNonce[8:], enc...)
+ data = append(data, tag...)
+ if _, err = state.conn.Write(data); err != nil {
+ return nil, errors.Wrap(err, "state.conn.Write")
}
- data := append(state.rNonce[:], enc...)
- data = append(data, idTag(state.Conf.Id, state.Conf.TimeSync, state.rNonce[:])...)
- state.conn.Write(data)
- return state
+ return state, nil
}
-// Process handshake message on the server side.
+// Server processes handshake message on the server side.
// This function is intended to be called on server's side.
// If this is the final handshake message, then new Peer object
-// will be created and used as a transport. If no mutually
-// authenticated Peer is ready, then return nil.
-func (h *Handshake) Server(data []byte) *Peer {
+// will be created and used as a transport.
+func (h *Handshake) Server(data []byte) (*Peer, error) {
// R + ENC(H(DSAPub), R, El(CDHPub)) + IDtag
if h.rNonce == nil && ((!h.Conf.Encless && len(data) >= 48) ||
(h.Conf.Encless && len(data) == EnclessEnlargeSize+h.Conf.MTU)) {
- h.rNonce = new([RSize]byte)
- copy(h.rNonce[:], data[:RSize])
+ h.rNonce = new([16]byte)
+ copy(h.rNonce[8:], data[:RSize])
// Decrypt remote public key
cDHRepr := new([32]byte)
if h.Conf.Encless {
out, err := EnclessDecode(
h.dsaPubH,
- h.rNonce[:],
+ h.rNonce,
data[RSize:len(data)-8],
)
if err != nil {
- log.Println("Unable to decode packet from", h.addr, err)
- return nil
+ return nil, errors.Wrap(err, wrapEnclessDecode)
}
copy(cDHRepr[:], out)
} else {
- salsa20.XORKeyStream(cDHRepr[:], data[RSize:RSize+32], h.rNonce[:], h.dsaPubH)
+ chacha20.XORKeyStream(cDHRepr[:], data[RSize:RSize+32], h.rNonce, h.dsaPubH)
}
// Generate DH keypair
var dhPubRepr *[32]byte
- h.dhPriv, dhPubRepr = dhKeypairGen()
+ var err error
+ if h.dhPriv, dhPubRepr, err = dhKeypairGen(); err != nil {
+ return nil, errors.Wrap(err, "dhKeypairGen")
+ }
// Compute shared key
cDH := new([32]byte)
h.key = dhKeyGen(h.dhPriv, cDH)
var encPub []byte
- var err error
if h.Conf.Encless {
encPub = make([]byte, h.Conf.MTU)
copy(encPub, dhPubRepr[:])
encPub, err = EnclessEncode(h.dsaPubH, h.rNonceNext(1), encPub)
if err != nil {
- panic(err)
+ return nil, errors.Wrap(err, wrapEnclessEncode)
}
} else {
encPub = make([]byte, 32)
- salsa20.XORKeyStream(encPub, dhPubRepr[:], h.rNonceNext(1), h.dsaPubH)
+ chacha20.XORKeyStream(encPub, dhPubRepr[:], h.rNonceNext(1), h.dsaPubH)
}
// Generate R* and encrypt them
h.rServer = new([RSize]byte)
if _, err = io.ReadFull(Rand, h.rServer[:]); err != nil {
- log.Fatalln("Error reading random for R:", err)
+ return nil, errors.Wrapf(err, wrapIoReadFull, "Rand")
}
h.sServer = new([SSize]byte)
if _, err = io.ReadFull(Rand, h.sServer[:]); err != nil {
- log.Fatalln("Error reading random for S:", err)
+ return nil, errors.Wrapf(err, wrapIoReadFull, "Rand")
}
var encRs []byte
if h.Conf.Noise && !h.Conf.Encless {
}
copy(encRs, append(h.rServer[:], h.sServer[:]...))
if h.Conf.Encless {
- encRs, err = EnclessEncode(h.key, h.rNonce[:], encRs)
+ encRs, err = EnclessEncode(h.key, h.rNonce, encRs)
if err != nil {
- panic(err)
+ return nil, errors.Wrap(err, wrapEnclessEncode)
}
} else {
- salsa20.XORKeyStream(encRs, encRs, h.rNonce[:], h.key)
+ chacha20.XORKeyStream(encRs, encRs, h.rNonce, h.key)
+ }
+
+ tag, err := idTag(h.Conf.ID, h.Conf.TimeSync, encPub)
+ if err != nil {
+ return nil, errors.Wrapf(err, wrapIDTag, h.Conf.ID.String(), h.Conf.TimeSync)
}
// Send that to client
- h.conn.Write(append(encPub, append(
- encRs, idTag(h.Conf.Id, h.Conf.TimeSync, encPub)...,
+ _, err = h.conn.Write(append(encPub, append(
+ encRs, tag...,
)...))
+ if err != nil {
+ return nil, errors.Wrap(err, "conn.Write")
+ }
h.LastPing = time.Now()
} else
// ENC(K, R+1, RS + RC + SC + Sign(DSAPriv, K)) + IDtag
data[:len(data)-8],
)
if err != nil {
- log.Println("Unable to decode packet from", h.addr, err)
- return nil
+ return nil, errors.Wrap(err, wrapEnclessDecode)
}
dec = dec[:RSize+RSize+SSize+ed25519.SignatureSize]
} else {
dec = make([]byte, RSize+RSize+SSize+ed25519.SignatureSize)
- salsa20.XORKeyStream(
+ chacha20.XORKeyStream(
dec,
data[:RSize+RSize+SSize+ed25519.SignatureSize],
h.rNonceNext(1),
)
}
if subtle.ConstantTimeCompare(dec[:RSize], h.rServer[:]) != 1 {
- log.Println("Invalid server's random number with", h.addr)
- return nil
+ return nil, errors.New("Invalid server's random number")
}
sign := new([ed25519.SignatureSize]byte)
copy(sign[:], dec[RSize+RSize+SSize:])
if !ed25519.Verify(h.Conf.Verifier.Pub, h.key[:], sign) {
- log.Println("Invalid signature from", h.addr)
- return nil
+ return nil, errors.New("Invalid signature")
}
// Send final answer to client
if h.Conf.Encless {
enc, err = EnclessEncode(h.key, h.rNonceNext(2), enc)
if err != nil {
- panic(err)
+ return nil, errors.Wrap(err, wrapEnclessEncode)
}
} else {
- salsa20.XORKeyStream(enc, enc, h.rNonceNext(2), h.key)
+ chacha20.XORKeyStream(enc, enc, h.rNonceNext(2), h.key)
+ }
+ tag, err := idTag(h.Conf.ID, h.Conf.TimeSync, enc)
+ if err != nil {
+ return nil, errors.Wrapf(err, wrapIDTag, h.Conf.ID.String(), h.Conf.TimeSync)
+ }
+ if _, err = h.conn.Write(append(enc, tag...)); err != nil {
+ return nil, errors.Wrap(err, "conn.Write")
}
- h.conn.Write(append(enc, idTag(h.Conf.Id, h.Conf.TimeSync, enc)...))
// Switch peer
- peer := newPeer(
+ peer, err := newPeer(
false,
h.addr,
h.conn,
h.Conf,
keyFromSecrets(h.sServer[:], dec[RSize+RSize:RSize+RSize+SSize]))
+ if err != nil {
+ return nil, errors.Wrap(err, "newPeer")
+ }
h.LastPing = time.Now()
- return peer
- } else {
- log.Println("Invalid handshake message from", h.addr)
+ return peer, nil
}
- return nil
+ return nil, nil
}
-// Process handshake message on the client side.
+// Client processes handshake message on the client side.
// This function is intended to be called on client's side.
// If this is the final handshake message, then new Peer object
// will be created and used as a transport. If no mutually
// authenticated Peer is ready, then return nil.
-func (h *Handshake) Client(data []byte) *Peer {
+func (h *Handshake) Client(data []byte) (*Peer, error) {
// ENC(H(DSAPub), R+1, El(SDHPub)) + ENC(K, R, RS + SS) + IDtag
if h.rServer == nil && h.key == nil &&
((!h.Conf.Encless && len(data) >= 80) ||
data[:len(data)/2],
)
if err != nil {
- log.Println("Unable to decode packet from", h.addr, err)
- return nil
+ return nil, errors.Wrap(err, wrapEnclessDecode)
}
copy(sDHRepr[:], tmp[:32])
} else {
- salsa20.XORKeyStream(sDHRepr[:], data[:32], h.rNonceNext(1), h.dsaPubH)
+ chacha20.XORKeyStream(sDHRepr[:], data[:32], h.rNonceNext(1), h.dsaPubH)
}
// Compute shared key
h.rServer = new([RSize]byte)
h.sServer = new([SSize]byte)
if h.Conf.Encless {
- tmp, err = EnclessDecode(
- h.key,
- h.rNonce[:],
- data[len(data)/2:len(data)-8],
- )
+ tmp, err = EnclessDecode(h.key, h.rNonce, data[len(data)/2:len(data)-8])
if err != nil {
- log.Println("Unable to decode packet from", h.addr, err)
- return nil
+ return nil, errors.Wrap(err, wrapEnclessDecode)
}
copy(h.rServer[:], tmp[:RSize])
copy(h.sServer[:], tmp[RSize:RSize+SSize])
} else {
decRs := make([]byte, RSize+SSize)
- salsa20.XORKeyStream(decRs, data[SSize:SSize+RSize+SSize], h.rNonce[:], h.key)
+ chacha20.XORKeyStream(decRs, data[SSize:SSize+RSize+SSize], h.rNonce, h.key)
copy(h.rServer[:], decRs[:RSize])
copy(h.sServer[:], decRs[RSize:])
}
// Generate R* and signature and encrypt them
h.rClient = new([RSize]byte)
if _, err = io.ReadFull(Rand, h.rClient[:]); err != nil {
- log.Fatalln("Error reading random for R:", err)
+ return nil, errors.Wrapf(err, wrapIoReadFull, "Rand")
}
h.sClient = new([SSize]byte)
if _, err = io.ReadFull(Rand, h.sClient[:]); err != nil {
- log.Fatalln("Error reading random for S:", err)
+ return nil, errors.Wrapf(err, wrapIoReadFull, "Rand")
}
sign := ed25519.Sign(h.Conf.DSAPriv, h.key[:])
if h.Conf.Encless {
enc, err = EnclessEncode(h.key, h.rNonceNext(1), enc)
if err != nil {
- panic(err)
+ return nil, errors.Wrap(err, wrapEnclessEncode)
}
} else {
- salsa20.XORKeyStream(enc, enc, h.rNonceNext(1), h.key)
+ chacha20.XORKeyStream(enc, enc, h.rNonceNext(1), h.key)
+ }
+
+ tag, err := idTag(h.Conf.ID, h.Conf.TimeSync, enc)
+ if err != nil {
+ return nil, errors.Wrapf(err, wrapIDTag, h.Conf.ID.String(), h.Conf.TimeSync)
}
// Send that to server
- h.conn.Write(append(enc, idTag(h.Conf.Id, h.Conf.TimeSync, enc)...))
+ if _, err = h.conn.Write(append(enc, tag...)); err != nil {
+ return nil, errors.Wrap(err, "conn.Write")
+ }
h.LastPing = time.Now()
} else
// ENC(K, R+2, RC) + IDtag
if h.Conf.Encless {
dec, err = EnclessDecode(h.key, h.rNonceNext(2), data[:len(data)-8])
if err != nil {
- log.Println("Unable to decode packet from", h.addr, err)
- return nil
+ return nil, errors.Wrap(err, wrapEnclessDecode)
}
dec = dec[:RSize]
} else {
dec = make([]byte, RSize)
- salsa20.XORKeyStream(dec, data[:RSize], h.rNonceNext(2), h.key)
+ chacha20.XORKeyStream(dec, data[:RSize], h.rNonceNext(2), h.key)
}
if subtle.ConstantTimeCompare(dec, h.rClient[:]) != 1 {
- log.Println("Invalid client's random number with", h.addr)
- return nil
+ return nil, errors.New("Invalid client's random number")
}
// Switch peer
- peer := newPeer(
+ peer, err := newPeer(
true,
h.addr,
h.conn,
h.Conf,
keyFromSecrets(h.sServer[:], h.sClient[:]),
)
+ if err != nil {
+ return nil, errors.Wrap(err, "newPeer")
+ }
h.LastPing = time.Now()
- return peer
- } else {
- log.Println("Invalid handshake stage from", h.addr)
+ return peer, nil
}
- return nil
+
+ // no peer yet, no error
+ return nil, nil
}