// Copyright 2016 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
package whisperv5
import (
"bytes"
"crypto/ecdsa"
crand "crypto/rand"
"crypto/sha256"
"fmt"
"runtime"
"sync"
"time"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/crypto"
"github.com/ethereum/go-ethereum/logger"
"github.com/ethereum/go-ethereum/logger/glog"
"github.com/ethereum/go-ethereum/p2p"
"github.com/ethereum/go-ethereum/rlp"
"golang.org/x/crypto/pbkdf2"
set "gopkg.in/fatih/set.v0"
)
// Whisper represents a dark communication interface through the Ethereum
// network, using its very own P2P communication layer.
type Whisper struct {
protocol p2p.Protocol
filters *Filters
privateKeys map[string]*ecdsa.PrivateKey
symKeys map[string][]byte
keyMu sync.RWMutex
envelopes map[common.Hash]*Envelope // Pool of envelopes currently tracked by this node
messages map[common.Hash]*ReceivedMessage // Pool of successfully decrypted messages, which are not expired yet
expirations map[uint32]*set.SetNonTS // Message expiration pool
poolMu sync.RWMutex // Mutex to sync the message and expiration pools
peers map[*Peer]struct{} // Set of currently active peers
peerMu sync.RWMutex // Mutex to sync the active peer set
mailServer MailServer
messageQueue chan *Envelope
p2pMsgQueue chan *Envelope
quit chan struct{}
overflow bool
test bool
}
// New creates a Whisper client ready to communicate through the Ethereum P2P network.
// Param s should be passed if you want to implement mail server, otherwise nil.
func NewWhisper(server MailServer) *Whisper {
whisper := &Whisper{
privateKeys: make(map[string]*ecdsa.PrivateKey),
symKeys: make(map[string][]byte),
envelopes: make(map[common.Hash]*Envelope),
messages: make(map[common.Hash]*ReceivedMessage),
expirations: make(map[uint32]*set.SetNonTS),
peers: make(map[*Peer]struct{}),
mailServer: server,
messageQueue: make(chan *Envelope, messageQueueLimit),
p2pMsgQueue: make(chan *Envelope, messageQueueLimit),
quit: make(chan struct{}),
}
whisper.filters = NewFilters(whisper)
// p2p whisper sub protocol handler
whisper.protocol = p2p.Protocol{
Name: ProtocolName,
Version: uint(ProtocolVersion),
Length: NumberOfMessageCodes,
Run: whisper.HandlePeer,
}
return whisper
}
// Protocols returns the whisper sub-protocols ran by this particular client.
func (w *Whisper) Protocols() []p2p.Protocol {
return []p2p.Protocol{w.protocol}
}
// Version returns the whisper sub-protocols version number.
func (w *Whisper) Version() uint {
return w.protocol.Version
}
func (w *Whisper) getPeer(peerID []byte) (*Peer, error) {
w.peerMu.Lock()
defer w.peerMu.Unlock()
for p := range w.peers {
id := p.peer.ID()
if bytes.Equal(peerID, id[:]) {
return p, nil
}
}
return nil, fmt.Errorf("Could not find peer with ID: %x", peerID)
}
// MarkPeerTrusted marks specific peer trusted, which will allow it
// to send historic (expired) messages.
func (w *Whisper) MarkPeerTrusted(peerID []byte) error {
p, err := w.getPeer(peerID)
if err != nil {
return err
}
p.trusted = true
return nil
}
func (w *Whisper) RequestHistoricMessages(peerID []byte, data []byte) error {
p, err := w.getPeer(peerID)
if err != nil {
return err
}
p.trusted = true
return p2p.Send(p.ws, p2pRequestCode, data)
}
func (w *Whisper) SendP2PMessage(peerID []byte, envelope *Envelope) error {
p, err := w.getPeer(peerID)
if err != nil {
return err
}
return p2p.Send(p.ws, p2pCode, envelope)
}
// NewIdentity generates a new cryptographic identity for the client, and injects
// it into the known identities for message decryption.
func (w *Whisper) NewIdentity() *ecdsa.PrivateKey {
key, err := crypto.GenerateKey()
if err != nil || !validatePrivateKey(key) {
key, err = crypto.GenerateKey() // retry once
}
if err != nil {
panic(err)
}
if !validatePrivateKey(key) {
panic("Failed to generate valid key")
}
w.keyMu.Lock()
defer w.keyMu.Unlock()
w.privateKeys[common.ToHex(crypto.FromECDSAPub(&key.PublicKey))] = key
return key
}
// DeleteIdentity deletes the specified key if it exists.
func (w *Whisper) DeleteIdentity(key string) {
w.keyMu.Lock()
defer w.keyMu.Unlock()
delete(w.privateKeys, key)
}
// HasIdentity checks if the the whisper node is configured with the private key
// of the specified public pair.
func (w *Whisper) HasIdentity(pubKey string) bool {
w.keyMu.RLock()
defer w.keyMu.RUnlock()
return w.privateKeys[pubKey] != nil
}
// GetIdentity retrieves the private key of the specified public identity.
func (w *Whisper) GetIdentity(pubKey string) *ecdsa.PrivateKey {
w.keyMu.RLock()
defer w.keyMu.RUnlock()
return w.privateKeys[pubKey]
}
func (w *Whisper) GenerateSymKey(name string) error {
const size = aesKeyLength * 2
buf := make([]byte, size)
_, err := crand.Read(buf)
if err != nil {
return err
} else if !validateSymmetricKey(buf) {
return fmt.Errorf("error in GenerateSymKey: crypto/rand failed to generate random data")
}
key := buf[:aesKeyLength]
salt := buf[aesKeyLength:]
derived, err := DeriveOneTimeKey(key, salt, EnvelopeVersion)
if err != nil {
return err
} else if !validateSymmetricKey(derived) {
return fmt.Errorf("failed to derive valid key")
}
w.keyMu.Lock()
defer w.keyMu.Unlock()
if w.symKeys[name] != nil {
return fmt.Errorf("Key with name [%s] already exists", name)
}
w.symKeys[name] = derived
return nil
}
func (w *Whisper) AddSymKey(name string, key []byte) error {
if w.HasSymKey(name) {
return fmt.Errorf("Key with name [%s] already exists", name)
}
derived, err := deriveKeyMaterial(key, EnvelopeVersion)
if err != nil {
return err
}
w.keyMu.Lock()
defer w.keyMu.Unlock()
// double check is necessary, because deriveKeyMaterial() is slow
if w.symKeys[name] != nil {
return fmt.Errorf("Key with name [%s] already exists", name)
}
w.symKeys[name] = derived
return nil
}
func (w *Whisper) HasSymKey(name string) bool {
w.keyMu.RLock()
defer w.keyMu.RUnlock()
return w.symKeys[name] != nil
}
func (w *Whisper) DeleteSymKey(name string) {
w.keyMu.Lock()
defer w.keyMu.Unlock()
delete(w.symKeys, name)
}
func (w *Whisper) GetSymKey(name string) []byte {
w.keyMu.RLock()
defer w.keyMu.RUnlock()
return w.symKeys[name]
}
// Watch installs a new message handler to run in case a matching packet arrives
// from the whisper network.
func (w *Whisper) Watch(f *Filter) uint32 {
return w.filters.Install(f)
}
func (w *Whisper) GetFilter(id uint32) *Filter {
return w.filters.Get(id)
}
// Unwatch removes an installed message handler.
func (w *Whisper) Unwatch(id uint32) {
w.filters.Uninstall(id)
}
// Send injects a message into the whisper send queue, to be distributed in the
// network in the coming cycles.
func (w *Whisper) Send(envelope *Envelope) error {
return w.add(envelope)
}
// Start implements node.Service, starting the background data propagation thread
// of the Whisper protocol.
func (w *Whisper) Start(*p2p.Server) error {
glog.V(logger.Info).Infoln("Whisper started")
go w.update()
numCPU := runtime.NumCPU()
for i := 0; i < numCPU; i++ {
go w.processQueue()
}
return nil
}
// Stop implements node.Service, stopping the background data propagation thread
// of the Whisper protocol.
func (w *Whisper) Stop() error {
close(w.quit)
glog.V(logger.Info).Infoln("Whisper stopped")
return nil
}
// handlePeer is called by the underlying P2P layer when the whisper sub-protocol
// connection is negotiated.
func (wh *Whisper) HandlePeer(peer *p2p.Peer, rw p2p.MsgReadWriter) error {
// Create the new peer and start tracking it
whisperPeer := newPeer(wh, peer, rw)
wh.peerMu.Lock()
wh.peers[whisperPeer] = struct{}{}
wh.peerMu.Unlock()
defer func() {
wh.peerMu.Lock()
delete(wh.peers, whisperPeer)
wh.peerMu.Unlock()
}()
// Run the peer handshake and state updates
if err := whisperPeer.handshake(); err != nil {
return err
}
whisperPeer.start()
defer whisperPeer.stop()
return wh.runMessageLoop(whisperPeer, rw)
}
// runMessageLoop reads and processes inbound messages directly to merge into client-global state.
func (wh *Whisper) runMessageLoop(p *Peer, rw p2p.MsgReadWriter) error {
for {
// fetch the next packet
packet, err := rw.ReadMsg()
if err != nil {
return err
}
switch packet.Code {
case statusCode:
// this should not happen, but no need to panic; just ignore this message.
glog.V(logger.Warn).Infof("%v: unxepected status message received", p.peer)
case messagesCode:
// decode the contained envelopes
var envelopes []*Envelope
if err := packet.Decode(&envelopes); err != nil {
glog.V(logger.Warn).Infof("%v: failed to decode envelope: [%v], peer will be disconnected", p.peer, err)
return fmt.Errorf("garbage received")
}
// inject all envelopes into the internal pool
for _, envelope := range envelopes {
if err := wh.add(envelope); err != nil {
glog.V(logger.Warn).Infof("%v: bad envelope received: [%v], peer will be disconnected", p.peer, err)
return fmt.Errorf("invalid envelope")
}
p.mark(envelope)
if wh.mailServer != nil {
wh.mailServer.Archive(envelope)
}
}
case p2pCode:
// peer-to-peer message, sent directly to peer bypassing PoW checks, etc.
// this message is not supposed to be forwarded to other peers, and
// therefore might not satisfy the PoW, expiry and other requirements.
// these messages are only accepted from the trusted peer.
if p.trusted {
var envelopes []*Envelope
if err := packet.Decode(&envelopes); err != nil {
glog.V(logger.Warn).Infof("%v: failed to decode direct message: [%v], peer will be disconnected", p.peer, err)
return fmt.Errorf("garbage received (directMessage)")
}
for _, envelope := range envelopes {
wh.postEvent(envelope, true)
}
}
case p2pRequestCode:
// Must be processed if mail server is implemented. Otherwise ignore.
if wh.mailServer != nil {
s := rlp.NewStream(packet.Payload, uint64(packet.Size))
data, err := s.Bytes()
if err == nil {
wh.mailServer.DeliverMail(p, data)
} else {
glog.V(logger.Error).Infof("%v: bad requestHistoricMessages received: [%v]", p.peer, err)
}
}
default:
// New message types might be implemented in the future versions of Whisper.
// For forward compatibility, just ignore.
}
packet.Discard()
}
}
// add inserts a new envelope into the message pool to be distributed within the
// whisper network. It also inserts the envelope into the expiration pool at the
// appropriate time-stamp. In case of error, connection should be dropped.
func (wh *Whisper) add(envelope *Envelope) error {
now := uint32(time.Now().Unix())
sent := envelope.Expiry - envelope.TTL
if sent > now {
if sent-SynchAllowance > now {
return fmt.Errorf("envelope created in the future [%x]", envelope.Hash())
} else {
// recalculate PoW, adjusted for the time difference, plus one second for latency
envelope.calculatePoW(sent - now + 1)
}
}
if envelope.Expiry < now {
if envelope.Expiry+SynchAllowance*2 < now {
return fmt.Errorf("very old message")
} else {
glog.V(logger.Debug).Infof("expired envelope dropped [%x]", envelope.Hash())
return nil // drop envelope without error
}
}
if len(envelope.Data) > MaxMessageLength {
return fmt.Errorf("huge messages are not allowed [%x]", envelope.Hash())
}
if len(envelope.Version) > 4 {
return fmt.Errorf("oversized version [%x]", envelope.Hash())
}
if len(envelope.AESNonce) > AESNonceMaxLength {
// the standard AES GSM nonce size is 12,
// but const gcmStandardNonceSize cannot be accessed directly
return fmt.Errorf("oversized AESNonce [%x]", envelope.Hash())
}
if len(envelope.Salt) > saltLength {
return fmt.Errorf("oversized salt [%x]", envelope.Hash())
}
if envelope.PoW() < MinimumPoW && !wh.test {
glog.V(logger.Debug).Infof("envelope with low PoW dropped: %f [%x]", envelope.PoW(), envelope.Hash())
return nil // drop envelope without error
}
hash := envelope.Hash()
wh.poolMu.Lock()
_, alreadyCached := wh.envelopes[hash]
if !alreadyCached {
wh.envelopes[hash] = envelope
if wh.expirations[envelope.Expiry] == nil {
wh.expirations[envelope.Expiry] = set.NewNonTS()
}
if !wh.expirations[envelope.Expiry].Has(hash) {
wh.expirations[envelope.Expiry].Add(hash)
}
}
wh.poolMu.Unlock()
if alreadyCached {
glog.V(logger.Detail).Infof("whisper envelope already cached [%x]\n", envelope.Hash())
} else {
glog.V(logger.Detail).Infof("cached whisper envelope [%x]: %v\n", envelope.Hash(), envelope)
wh.postEvent(envelope, false) // notify the local node about the new message
}
return nil
}
// postEvent queues the message for further processing.
func (w *Whisper) postEvent(envelope *Envelope, isP2P bool) {
// if the version of incoming message is higher than
// currently supported version, we can not decrypt it,
// and therefore just ignore this message
if envelope.Ver() <= EnvelopeVersion {
if isP2P {
w.p2pMsgQueue <- envelope
} else {
w.checkOverflow()
w.messageQueue <- envelope
}
}
}
// checkOverflow checks if message queue overflow occurs and reports it if necessary.
func (w *Whisper) checkOverflow() {
queueSize := len(w.messageQueue)
if queueSize == messageQueueLimit {
if !w.overflow {
w.overflow = true
glog.V(logger.Warn).Infoln("message queue overflow")
}
} else if queueSize <= messageQueueLimit/2 {
if w.overflow {
w.overflow = false
}
}
}
// processQueue delivers the messages to the watchers during the lifetime of the whisper node.
func (w *Whisper) processQueue() {
var e *Envelope
for {
select {
case <-w.quit:
return
case e = <-w.messageQueue:
w.filters.NotifyWatchers(e, false)
case e = <-w.p2pMsgQueue:
w.filters.NotifyWatchers(e, true)
}
}
}
// update loops until the lifetime of the whisper node, updating its internal
// state by expiring stale messages from the pool.
func (w *Whisper) update() {
// Start a ticker to check for expirations
expire := time.NewTicker(expirationCycle)
// Repeat updates until termination is requested
for {
select {
case <-expire.C:
w.expire()
case <-w.quit:
return
}
}
}
// expire iterates over all the expiration timestamps, removing all stale
// messages from the pools.
func (w *Whisper) expire() {
w.poolMu.Lock()
defer w.poolMu.Unlock()
now := uint32(time.Now().Unix())
for then, hashSet := range w.expirations {
// Short circuit if a future time
if then > now {
continue
}
// Dump all expired messages and remove timestamp
hashSet.Each(func(v interface{}) bool {
delete(w.envelopes, v.(common.Hash))
delete(w.messages, v.(common.Hash))
return true
})
w.expirations[then].Clear()
}
}
// envelopes retrieves all the messages currently pooled by the node.
func (w *Whisper) Envelopes() []*Envelope {
w.poolMu.RLock()
defer w.poolMu.RUnlock()
all := make([]*Envelope, 0, len(w.envelopes))
for _, envelope := range w.envelopes {
all = append(all, envelope)
}
return all
}
// Messages retrieves all the decrypted messages matching a filter id.
func (w *Whisper) Messages(id uint32) []*ReceivedMessage {
result := make([]*ReceivedMessage, 0)
w.poolMu.RLock()
defer w.poolMu.RUnlock()
if filter := w.filters.Get(id); filter != nil {
for _, msg := range w.messages {
if filter.MatchMessage(msg) {
result = append(result, msg)
}
}
}
return result
}
func (w *Whisper) addDecryptedMessage(msg *ReceivedMessage) {
w.poolMu.Lock()
defer w.poolMu.Unlock()
w.messages[msg.EnvelopeHash] = msg
}
func ValidatePublicKey(k *ecdsa.PublicKey) bool {
return k != nil && k.X != nil && k.Y != nil && k.X.Sign() != 0 && k.Y.Sign() != 0
}
func validatePrivateKey(k *ecdsa.PrivateKey) bool {
if k == nil || k.D == nil || k.D.Sign() == 0 {
return false
}
return ValidatePublicKey(&k.PublicKey)
}
// validateSymmetricKey returns false if the key contains all zeros
func validateSymmetricKey(k []byte) bool {
return len(k) > 0 && !containsOnlyZeros(k)
}
func containsOnlyZeros(data []byte) bool {
for _, b := range data {
if b != 0 {
return false
}
}
return true
}
func bytesToIntLittleEndian(b []byte) (res uint64) {
mul := uint64(1)
for i := 0; i < len(b); i++ {
res += uint64(b[i]) * mul
mul *= 256
}
return res
}
func BytesToIntBigEndian(b []byte) (res uint64) {
for i := 0; i < len(b); i++ {
res *= 256
res += uint64(b[i])
}
return res
}
// DeriveSymmetricKey derives symmetric key material from the key or password.
// pbkdf2 is used for security, in case people use password instead of randomly generated keys.
func deriveKeyMaterial(key []byte, version uint64) (derivedKey []byte, err error) {
if version == 0 {
// kdf should run no less than 0.1 seconds on average compute,
// because it's a once in a session experience
derivedKey := pbkdf2.Key(key, nil, 65356, aesKeyLength, sha256.New)
return derivedKey, nil
} else {
return nil, unknownVersionError(version)
}
}
