282 lines
9.6 KiB
Go
282 lines
9.6 KiB
Go
// Copyright 2019 The go-ethereum Authors
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// This file is part of the go-ethereum library.
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//
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// The go-ethereum library is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Lesser General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// The go-ethereum library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public License
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// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
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package pss
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import (
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"crypto/ecdsa"
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"errors"
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"fmt"
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"sync"
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"github.com/ethereum/go-ethereum/common"
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"github.com/ethereum/go-ethereum/crypto"
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"github.com/ethereum/go-ethereum/metrics"
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"github.com/ethereum/go-ethereum/swarm/log"
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whisper "github.com/ethereum/go-ethereum/whisper/whisperv6"
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)
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type KeyStore struct {
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w *whisper.Whisper // key and encryption backend
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mx sync.RWMutex
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pubKeyPool map[string]map[Topic]*pssPeer // mapping of hex public keys to peer address by topic.
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symKeyPool map[string]map[Topic]*pssPeer // mapping of symkeyids to peer address by topic.
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symKeyDecryptCache []*string // fast lookup of symkeys recently used for decryption; last used is on top of stack
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symKeyDecryptCacheCursor int // modular cursor pointing to last used, wraps on symKeyDecryptCache array
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}
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func loadKeyStore() *KeyStore {
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return &KeyStore{
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w: whisper.New(&whisper.DefaultConfig),
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pubKeyPool: make(map[string]map[Topic]*pssPeer),
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symKeyPool: make(map[string]map[Topic]*pssPeer),
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symKeyDecryptCache: make([]*string, defaultSymKeyCacheCapacity),
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}
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}
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func (ks *KeyStore) isSymKeyStored(key string) bool {
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ks.mx.RLock()
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defer ks.mx.RUnlock()
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var ok bool
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_, ok = ks.symKeyPool[key]
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return ok
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}
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func (ks *KeyStore) isPubKeyStored(key string) bool {
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ks.mx.RLock()
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defer ks.mx.RUnlock()
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var ok bool
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_, ok = ks.pubKeyPool[key]
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return ok
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}
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func (ks *KeyStore) getPeerSym(symkeyid string, topic Topic) (*pssPeer, bool) {
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ks.mx.RLock()
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defer ks.mx.RUnlock()
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psp, ok := ks.symKeyPool[symkeyid][topic]
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return psp, ok
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}
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func (ks *KeyStore) getPeerPub(pubkeyid string, topic Topic) (*pssPeer, bool) {
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ks.mx.RLock()
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defer ks.mx.RUnlock()
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psp, ok := ks.pubKeyPool[pubkeyid][topic]
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return psp, ok
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}
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// Links a peer ECDSA public key to a topic.
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// This is required for asymmetric message exchange on the given topic.
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// The value in `address` will be used as a routing hint for the public key / topic association.
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func (ks *KeyStore) SetPeerPublicKey(pubkey *ecdsa.PublicKey, topic Topic, address PssAddress) error {
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if err := validateAddress(address); err != nil {
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return err
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}
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pubkeybytes := crypto.FromECDSAPub(pubkey)
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if len(pubkeybytes) == 0 {
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return fmt.Errorf("invalid public key: %v", pubkey)
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}
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pubkeyid := common.ToHex(pubkeybytes)
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psp := &pssPeer{
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address: address,
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}
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ks.mx.Lock()
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if _, ok := ks.pubKeyPool[pubkeyid]; !ok {
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ks.pubKeyPool[pubkeyid] = make(map[Topic]*pssPeer)
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}
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ks.pubKeyPool[pubkeyid][topic] = psp
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ks.mx.Unlock()
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log.Trace("added pubkey", "pubkeyid", pubkeyid, "topic", topic, "address", address)
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return nil
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}
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// adds a symmetric key to the pss key pool, and optionally adds the key to the
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// collection of keys used to attempt symmetric decryption of incoming messages
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func (ks *KeyStore) addSymmetricKeyToPool(keyid string, topic Topic, address PssAddress, addtocache bool, protected bool) {
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psp := &pssPeer{
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address: address,
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protected: protected,
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}
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ks.mx.Lock()
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if _, ok := ks.symKeyPool[keyid]; !ok {
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ks.symKeyPool[keyid] = make(map[Topic]*pssPeer)
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}
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ks.symKeyPool[keyid][topic] = psp
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ks.mx.Unlock()
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if addtocache {
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ks.symKeyDecryptCacheCursor++
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ks.symKeyDecryptCache[ks.symKeyDecryptCacheCursor%cap(ks.symKeyDecryptCache)] = &keyid
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}
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}
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// Returns all recorded topic and address combination for a specific public key
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func (ks *KeyStore) GetPublickeyPeers(keyid string) (topic []Topic, address []PssAddress, err error) {
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ks.mx.RLock()
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defer ks.mx.RUnlock()
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for t, peer := range ks.pubKeyPool[keyid] {
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topic = append(topic, t)
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address = append(address, peer.address)
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}
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return topic, address, nil
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}
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func (ks *KeyStore) getPeerAddress(keyid string, topic Topic) (PssAddress, error) {
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ks.mx.RLock()
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defer ks.mx.RUnlock()
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if peers, ok := ks.pubKeyPool[keyid]; ok {
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if t, ok := peers[topic]; ok {
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return t.address, nil
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}
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}
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return nil, fmt.Errorf("peer with pubkey %s, topic %x not found", keyid, topic)
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}
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// Attempt to decrypt, validate and unpack a symmetrically encrypted message.
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// If successful, returns the unpacked whisper ReceivedMessage struct
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// encapsulating the decrypted message, and the whisper backend id
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// of the symmetric key used to decrypt the message.
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// It fails if decryption of the message fails or if the message is corrupted.
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func (ks *KeyStore) processSym(envelope *whisper.Envelope) (*whisper.ReceivedMessage, string, PssAddress, error) {
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metrics.GetOrRegisterCounter("pss.process.sym", nil).Inc(1)
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for i := ks.symKeyDecryptCacheCursor; i > ks.symKeyDecryptCacheCursor-cap(ks.symKeyDecryptCache) && i > 0; i-- {
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symkeyid := ks.symKeyDecryptCache[i%cap(ks.symKeyDecryptCache)]
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symkey, err := ks.w.GetSymKey(*symkeyid)
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if err != nil {
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continue
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}
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recvmsg, err := envelope.OpenSymmetric(symkey)
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if err != nil {
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continue
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}
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if !recvmsg.ValidateAndParse() {
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return nil, "", nil, errors.New("symmetrically encrypted message has invalid signature or is corrupt")
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}
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var from PssAddress
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ks.mx.RLock()
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if ks.symKeyPool[*symkeyid][Topic(envelope.Topic)] != nil {
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from = ks.symKeyPool[*symkeyid][Topic(envelope.Topic)].address
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}
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ks.mx.RUnlock()
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ks.symKeyDecryptCacheCursor++
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ks.symKeyDecryptCache[ks.symKeyDecryptCacheCursor%cap(ks.symKeyDecryptCache)] = symkeyid
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return recvmsg, *symkeyid, from, nil
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}
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return nil, "", nil, errors.New("could not decrypt message")
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}
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// Attempt to decrypt, validate and unpack an asymmetrically encrypted message.
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// If successful, returns the unpacked whisper ReceivedMessage struct
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// encapsulating the decrypted message, and the byte representation of
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// the public key used to decrypt the message.
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// It fails if decryption of message fails, or if the message is corrupted.
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func (ks *Pss) processAsym(envelope *whisper.Envelope) (*whisper.ReceivedMessage, string, PssAddress, error) {
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metrics.GetOrRegisterCounter("pss.process.asym", nil).Inc(1)
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recvmsg, err := envelope.OpenAsymmetric(ks.privateKey)
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if err != nil {
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return nil, "", nil, fmt.Errorf("could not decrypt message: %s", err)
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}
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// check signature (if signed), strip padding
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if !recvmsg.ValidateAndParse() {
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return nil, "", nil, errors.New("invalid message")
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}
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pubkeyid := common.ToHex(crypto.FromECDSAPub(recvmsg.Src))
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var from PssAddress
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ks.mx.RLock()
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if ks.pubKeyPool[pubkeyid][Topic(envelope.Topic)] != nil {
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from = ks.pubKeyPool[pubkeyid][Topic(envelope.Topic)].address
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}
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ks.mx.RUnlock()
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return recvmsg, pubkeyid, from, nil
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}
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// Symkey garbage collection
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// a key is removed if:
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// - it is not marked as protected
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// - it is not in the incoming decryption cache
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func (ks *Pss) cleanKeys() (count int) {
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ks.mx.Lock()
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defer ks.mx.Unlock()
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for keyid, peertopics := range ks.symKeyPool {
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var expiredtopics []Topic
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for topic, psp := range peertopics {
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if psp.protected {
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continue
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}
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var match bool
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for i := ks.symKeyDecryptCacheCursor; i > ks.symKeyDecryptCacheCursor-cap(ks.symKeyDecryptCache) && i > 0; i-- {
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cacheid := ks.symKeyDecryptCache[i%cap(ks.symKeyDecryptCache)]
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if *cacheid == keyid {
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match = true
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}
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}
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if !match {
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expiredtopics = append(expiredtopics, topic)
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}
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}
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for _, topic := range expiredtopics {
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delete(ks.symKeyPool[keyid], topic)
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log.Trace("symkey cleanup deletion", "symkeyid", keyid, "topic", topic, "val", ks.symKeyPool[keyid])
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count++
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}
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}
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return count
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}
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// Automatically generate a new symkey for a topic and address hint
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func (ks *KeyStore) GenerateSymmetricKey(topic Topic, address PssAddress, addToCache bool) (string, error) {
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keyid, err := ks.w.GenerateSymKey()
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if err == nil {
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ks.addSymmetricKeyToPool(keyid, topic, address, addToCache, false)
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}
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return keyid, err
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}
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// Returns a symmetric key byte sequence stored in the whisper backend by its unique id.
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// Passes on the error value from the whisper backend.
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func (ks *KeyStore) GetSymmetricKey(symkeyid string) ([]byte, error) {
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return ks.w.GetSymKey(symkeyid)
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}
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// Links a peer symmetric key (arbitrary byte sequence) to a topic.
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//
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// This is required for symmetrically encrypted message exchange on the given topic.
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//
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// The key is stored in the whisper backend.
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//
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// If addtocache is set to true, the key will be added to the cache of keys
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// used to attempt symmetric decryption of incoming messages.
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//
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// Returns a string id that can be used to retrieve the key bytes
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// from the whisper backend (see pss.GetSymmetricKey())
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func (ks *KeyStore) SetSymmetricKey(key []byte, topic Topic, address PssAddress, addtocache bool) (string, error) {
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if err := validateAddress(address); err != nil {
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return "", err
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}
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return ks.setSymmetricKey(key, topic, address, addtocache, true)
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}
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func (ks *KeyStore) setSymmetricKey(key []byte, topic Topic, address PssAddress, addtocache bool, protected bool) (string, error) {
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keyid, err := ks.w.AddSymKeyDirect(key)
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if err == nil {
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ks.addSymmetricKeyToPool(keyid, topic, address, addtocache, protected)
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}
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return keyid, err
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}
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