ba996f5e27
* whisper: refactored message processing * whisper: final polishing * whisper: logging updated * whisper: moved the check, changed the default PoW * whisper: refactoring of message queuing * whisper: refactored parameters
384 lines
11 KiB
Go
384 lines
11 KiB
Go
// 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/>.
|
|
|
|
// Contains the Whisper protocol Message element.
|
|
|
|
package whisperv5
|
|
|
|
import (
|
|
"crypto/aes"
|
|
"crypto/cipher"
|
|
"crypto/ecdsa"
|
|
crand "crypto/rand"
|
|
"crypto/sha256"
|
|
"errors"
|
|
"fmt"
|
|
mrand "math/rand"
|
|
|
|
"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"
|
|
"golang.org/x/crypto/pbkdf2"
|
|
)
|
|
|
|
// Options specifies the exact way a message should be wrapped into an Envelope.
|
|
type MessageParams struct {
|
|
TTL uint32
|
|
Src *ecdsa.PrivateKey
|
|
Dst *ecdsa.PublicKey
|
|
KeySym []byte
|
|
Topic TopicType
|
|
WorkTime uint32
|
|
PoW float64
|
|
Payload []byte
|
|
Padding []byte
|
|
}
|
|
|
|
// SentMessage represents an end-user data packet to transmit through the
|
|
// Whisper protocol. These are wrapped into Envelopes that need not be
|
|
// understood by intermediate nodes, just forwarded.
|
|
type SentMessage struct {
|
|
Raw []byte
|
|
}
|
|
|
|
// ReceivedMessage represents a data packet to be received through the
|
|
// Whisper protocol.
|
|
type ReceivedMessage struct {
|
|
Raw []byte
|
|
|
|
Payload []byte
|
|
Padding []byte
|
|
Signature []byte
|
|
|
|
PoW float64 // Proof of work as described in the Whisper spec
|
|
Sent uint32 // Time when the message was posted into the network
|
|
TTL uint32 // Maximum time to live allowed for the message
|
|
Src *ecdsa.PublicKey // Message recipient (identity used to decode the message)
|
|
Dst *ecdsa.PublicKey // Message recipient (identity used to decode the message)
|
|
Topic TopicType
|
|
|
|
SymKeyHash common.Hash // The Keccak256Hash of the key, associated with the Topic
|
|
EnvelopeHash common.Hash // Message envelope hash to act as a unique id
|
|
EnvelopeVersion uint64
|
|
}
|
|
|
|
func isMessageSigned(flags byte) bool {
|
|
return (flags & signatureFlag) != 0
|
|
}
|
|
|
|
func (msg *ReceivedMessage) isSymmetricEncryption() bool {
|
|
return msg.SymKeyHash != common.Hash{}
|
|
}
|
|
|
|
func (msg *ReceivedMessage) isAsymmetricEncryption() bool {
|
|
return msg.Dst != nil
|
|
}
|
|
|
|
func DeriveOneTimeKey(key []byte, salt []byte, version uint64) ([]byte, error) {
|
|
if version == 0 {
|
|
derivedKey := pbkdf2.Key(key, salt, 8, aesKeyLength, sha256.New)
|
|
return derivedKey, nil
|
|
} else {
|
|
return nil, unknownVersionError(version)
|
|
}
|
|
}
|
|
|
|
// NewMessage creates and initializes a non-signed, non-encrypted Whisper message.
|
|
func NewSentMessage(params *MessageParams) *SentMessage {
|
|
msg := SentMessage{}
|
|
msg.Raw = make([]byte, 1, len(params.Payload)+len(params.Payload)+signatureLength+padSizeLimitUpper)
|
|
msg.Raw[0] = 0 // set all the flags to zero
|
|
msg.appendPadding(params)
|
|
msg.Raw = append(msg.Raw, params.Payload...)
|
|
return &msg
|
|
}
|
|
|
|
// appendPadding appends the pseudorandom padding bytes and sets the padding flag.
|
|
// The last byte contains the size of padding (thus, its size must not exceed 256).
|
|
func (msg *SentMessage) appendPadding(params *MessageParams) {
|
|
total := len(params.Payload) + 1
|
|
if params.Src != nil {
|
|
total += signatureLength
|
|
}
|
|
padChunk := padSizeLimitUpper
|
|
if total <= padSizeLimitLower {
|
|
padChunk = padSizeLimitLower
|
|
}
|
|
odd := total % padChunk
|
|
if odd > 0 {
|
|
padSize := padChunk - odd
|
|
if padSize > 255 {
|
|
// this algorithm is only valid if padSizeLimitUpper <= 256.
|
|
// if padSizeLimitUpper will ever change, please fix the algorithm
|
|
// (for more information see ReceivedMessage.extractPadding() function).
|
|
panic("please fix the padding algorithm before releasing new version")
|
|
}
|
|
buf := make([]byte, padSize)
|
|
randomize(buf[1:])
|
|
buf[0] = byte(padSize)
|
|
if params.Padding != nil {
|
|
copy(buf[1:], params.Padding)
|
|
}
|
|
msg.Raw = append(msg.Raw, buf...)
|
|
msg.Raw[0] |= byte(0x1) // number of bytes indicating the padding size
|
|
}
|
|
}
|
|
|
|
// sign calculates and sets the cryptographic signature for the message,
|
|
// also setting the sign flag.
|
|
func (msg *SentMessage) sign(key *ecdsa.PrivateKey) error {
|
|
if isMessageSigned(msg.Raw[0]) {
|
|
// this should not happen, but no reason to panic
|
|
glog.V(logger.Error).Infof("Trying to sign a message which was already signed")
|
|
return nil
|
|
}
|
|
|
|
msg.Raw[0] |= signatureFlag
|
|
hash := crypto.Keccak256(msg.Raw)
|
|
signature, err := crypto.Sign(hash, key)
|
|
if err != nil {
|
|
msg.Raw[0] &= ^signatureFlag // clear the flag
|
|
return err
|
|
}
|
|
msg.Raw = append(msg.Raw, signature...)
|
|
return nil
|
|
}
|
|
|
|
// encryptAsymmetric encrypts a message with a public key.
|
|
func (msg *SentMessage) encryptAsymmetric(key *ecdsa.PublicKey) error {
|
|
if !ValidatePublicKey(key) {
|
|
return fmt.Errorf("Invalid public key provided for asymmetric encryption")
|
|
}
|
|
encrypted, err := crypto.Encrypt(key, msg.Raw)
|
|
if err == nil {
|
|
msg.Raw = encrypted
|
|
}
|
|
return err
|
|
}
|
|
|
|
// encryptSymmetric encrypts a message with a topic key, using AES-GCM-256.
|
|
// nonce size should be 12 bytes (see cipher.gcmStandardNonceSize).
|
|
func (msg *SentMessage) encryptSymmetric(key []byte) (salt []byte, nonce []byte, err error) {
|
|
if !validateSymmetricKey(key) {
|
|
return nil, nil, errors.New("invalid key provided for symmetric encryption")
|
|
}
|
|
|
|
salt = make([]byte, saltLength)
|
|
_, err = crand.Read(salt)
|
|
if err != nil {
|
|
return nil, nil, err
|
|
} else if !validateSymmetricKey(salt) {
|
|
return nil, nil, errors.New("crypto/rand failed to generate salt")
|
|
}
|
|
|
|
derivedKey, err := DeriveOneTimeKey(key, salt, EnvelopeVersion)
|
|
if err != nil {
|
|
return nil, nil, err
|
|
}
|
|
if !validateSymmetricKey(derivedKey) {
|
|
return nil, nil, errors.New("failed to derive one-time key")
|
|
}
|
|
block, err := aes.NewCipher(derivedKey)
|
|
if err != nil {
|
|
return nil, nil, err
|
|
}
|
|
aesgcm, err := cipher.NewGCM(block)
|
|
if err != nil {
|
|
return nil, nil, err
|
|
}
|
|
|
|
// never use more than 2^32 random nonces with a given key
|
|
nonce = make([]byte, aesgcm.NonceSize())
|
|
_, err = crand.Read(nonce)
|
|
if err != nil {
|
|
return nil, nil, err
|
|
} else if !validateSymmetricKey(nonce) {
|
|
return nil, nil, errors.New("crypto/rand failed to generate nonce")
|
|
}
|
|
|
|
msg.Raw = aesgcm.Seal(nil, nonce, msg.Raw, nil)
|
|
return salt, nonce, nil
|
|
}
|
|
|
|
// Wrap bundles the message into an Envelope to transmit over the network.
|
|
//
|
|
// pow (Proof Of Work) controls how much time to spend on hashing the message,
|
|
// inherently controlling its priority through the network (smaller hash, bigger
|
|
// priority).
|
|
//
|
|
// The user can control the amount of identity, privacy and encryption through
|
|
// the options parameter as follows:
|
|
// - options.From == nil && options.To == nil: anonymous broadcast
|
|
// - options.From != nil && options.To == nil: signed broadcast (known sender)
|
|
// - options.From == nil && options.To != nil: encrypted anonymous message
|
|
// - options.From != nil && options.To != nil: encrypted signed message
|
|
func (msg *SentMessage) Wrap(options *MessageParams) (envelope *Envelope, err error) {
|
|
if options.TTL == 0 {
|
|
options.TTL = DefaultTTL
|
|
}
|
|
if options.Src != nil {
|
|
err = msg.sign(options.Src)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
}
|
|
if len(msg.Raw) > MaxMessageLength {
|
|
glog.V(logger.Error).Infof("Message size must not exceed %d bytes", MaxMessageLength)
|
|
return nil, errors.New("Oversized message")
|
|
}
|
|
var salt, nonce []byte
|
|
if options.Dst != nil {
|
|
err = msg.encryptAsymmetric(options.Dst)
|
|
} else if options.KeySym != nil {
|
|
salt, nonce, err = msg.encryptSymmetric(options.KeySym)
|
|
} else {
|
|
err = errors.New("Unable to encrypt the message: neither Dst nor Key")
|
|
}
|
|
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
envelope = NewEnvelope(options.TTL, options.Topic, salt, nonce, msg)
|
|
err = envelope.Seal(options)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
return envelope, nil
|
|
}
|
|
|
|
// decryptSymmetric decrypts a message with a topic key, using AES-GCM-256.
|
|
// nonce size should be 12 bytes (see cipher.gcmStandardNonceSize).
|
|
func (msg *ReceivedMessage) decryptSymmetric(key []byte, salt []byte, nonce []byte) error {
|
|
derivedKey, err := DeriveOneTimeKey(key, salt, msg.EnvelopeVersion)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
|
|
block, err := aes.NewCipher(derivedKey)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
aesgcm, err := cipher.NewGCM(block)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
if len(nonce) != aesgcm.NonceSize() {
|
|
info := fmt.Sprintf("Wrong AES nonce size - want: %d, got: %d", len(nonce), aesgcm.NonceSize())
|
|
glog.V(logger.Error).Infof(info)
|
|
return errors.New(info)
|
|
}
|
|
decrypted, err := aesgcm.Open(nil, nonce, msg.Raw, nil)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
msg.Raw = decrypted
|
|
return nil
|
|
}
|
|
|
|
// decryptAsymmetric decrypts an encrypted payload with a private key.
|
|
func (msg *ReceivedMessage) decryptAsymmetric(key *ecdsa.PrivateKey) error {
|
|
decrypted, err := crypto.Decrypt(key, msg.Raw)
|
|
if err == nil {
|
|
msg.Raw = decrypted
|
|
}
|
|
return err
|
|
}
|
|
|
|
// Validate checks the validity and extracts the fields in case of success
|
|
func (msg *ReceivedMessage) Validate() bool {
|
|
end := len(msg.Raw)
|
|
if end < 1 {
|
|
return false
|
|
}
|
|
|
|
if isMessageSigned(msg.Raw[0]) {
|
|
end -= signatureLength
|
|
if end <= 1 {
|
|
return false
|
|
}
|
|
msg.Signature = msg.Raw[end:]
|
|
msg.Src = msg.SigToPubKey()
|
|
if msg.Src == nil {
|
|
return false
|
|
}
|
|
}
|
|
|
|
padSize, ok := msg.extractPadding(end)
|
|
if !ok {
|
|
return false
|
|
}
|
|
|
|
msg.Payload = msg.Raw[1+padSize : end]
|
|
return true
|
|
}
|
|
|
|
// extractPadding extracts the padding from raw message.
|
|
// although we don't support sending messages with padding size
|
|
// exceeding 255 bytes, such messages are perfectly valid, and
|
|
// can be successfully decrypted.
|
|
func (msg *ReceivedMessage) extractPadding(end int) (int, bool) {
|
|
paddingSize := 0
|
|
sz := int(msg.Raw[0] & paddingMask) // number of bytes containing the entire size of padding, could be zero
|
|
if sz != 0 {
|
|
paddingSize = int(bytesToIntLittleEndian(msg.Raw[1 : 1+sz]))
|
|
if paddingSize < sz || paddingSize+1 > end {
|
|
return 0, false
|
|
}
|
|
msg.Padding = msg.Raw[1+sz : 1+paddingSize]
|
|
}
|
|
return paddingSize, true
|
|
}
|
|
|
|
// Recover retrieves the public key of the message signer.
|
|
func (msg *ReceivedMessage) SigToPubKey() *ecdsa.PublicKey {
|
|
defer func() { recover() }() // in case of invalid signature
|
|
|
|
pub, err := crypto.SigToPub(msg.hash(), msg.Signature)
|
|
if err != nil {
|
|
glog.V(logger.Error).Infof("Could not get public key from signature: %v", err)
|
|
return nil
|
|
}
|
|
return pub
|
|
}
|
|
|
|
// hash calculates the SHA3 checksum of the message flags, payload and padding.
|
|
func (msg *ReceivedMessage) hash() []byte {
|
|
if isMessageSigned(msg.Raw[0]) {
|
|
sz := len(msg.Raw) - signatureLength
|
|
return crypto.Keccak256(msg.Raw[:sz])
|
|
}
|
|
return crypto.Keccak256(msg.Raw)
|
|
}
|
|
|
|
// rand.Rand provides a Read method in Go 1.7 and later,
|
|
// but we can't use it yet.
|
|
func randomize(b []byte) {
|
|
cnt := 0
|
|
val := mrand.Int63()
|
|
for n := 0; n < len(b); n++ {
|
|
b[n] = byte(val)
|
|
val >>= 8
|
|
cnt++
|
|
if cnt >= 7 {
|
|
cnt = 0
|
|
val = mrand.Int63()
|
|
}
|
|
}
|
|
}
|