bsc/ethstats/ethstats.go
Martin Holst Swende c2e0abce2e
ethstats: set readlimit on ethstats server connection (#26207)
This prevents DoS when connected to a malicious ethstats server.
2022-11-17 15:33:03 +01:00

819 lines
24 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/>.
// Package ethstats implements the network stats reporting service.
package ethstats
import (
"context"
"encoding/json"
"errors"
"fmt"
"math/big"
"net/http"
"runtime"
"strconv"
"strings"
"sync"
"time"
"github.com/ethereum/go-ethereum"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/common/mclock"
"github.com/ethereum/go-ethereum/consensus"
"github.com/ethereum/go-ethereum/core"
"github.com/ethereum/go-ethereum/core/types"
ethproto "github.com/ethereum/go-ethereum/eth/protocols/eth"
"github.com/ethereum/go-ethereum/event"
"github.com/ethereum/go-ethereum/les"
"github.com/ethereum/go-ethereum/log"
"github.com/ethereum/go-ethereum/miner"
"github.com/ethereum/go-ethereum/node"
"github.com/ethereum/go-ethereum/p2p"
"github.com/ethereum/go-ethereum/rpc"
"github.com/gorilla/websocket"
)
const (
// historyUpdateRange is the number of blocks a node should report upon login or
// history request.
historyUpdateRange = 50
// txChanSize is the size of channel listening to NewTxsEvent.
// The number is referenced from the size of tx pool.
txChanSize = 4096
// chainHeadChanSize is the size of channel listening to ChainHeadEvent.
chainHeadChanSize = 10
messageSizeLimit = 15 * 1024 * 1024
)
// backend encompasses the bare-minimum functionality needed for ethstats reporting
type backend interface {
SubscribeChainHeadEvent(ch chan<- core.ChainHeadEvent) event.Subscription
SubscribeNewTxsEvent(ch chan<- core.NewTxsEvent) event.Subscription
CurrentHeader() *types.Header
HeaderByNumber(ctx context.Context, number rpc.BlockNumber) (*types.Header, error)
GetTd(ctx context.Context, hash common.Hash) *big.Int
Stats() (pending int, queued int)
SyncProgress() ethereum.SyncProgress
}
// fullNodeBackend encompasses the functionality necessary for a full node
// reporting to ethstats
type fullNodeBackend interface {
backend
Miner() *miner.Miner
BlockByNumber(ctx context.Context, number rpc.BlockNumber) (*types.Block, error)
CurrentBlock() *types.Block
SuggestGasTipCap(ctx context.Context) (*big.Int, error)
}
// Service implements an Ethereum netstats reporting daemon that pushes local
// chain statistics up to a monitoring server.
type Service struct {
server *p2p.Server // Peer-to-peer server to retrieve networking infos
backend backend
engine consensus.Engine // Consensus engine to retrieve variadic block fields
node string // Name of the node to display on the monitoring page
pass string // Password to authorize access to the monitoring page
host string // Remote address of the monitoring service
pongCh chan struct{} // Pong notifications are fed into this channel
histCh chan []uint64 // History request block numbers are fed into this channel
headSub event.Subscription
txSub event.Subscription
}
// connWrapper is a wrapper to prevent concurrent-write or concurrent-read on the
// websocket.
//
// From Gorilla websocket docs:
//
// Connections support one concurrent reader and one concurrent writer. Applications are
// responsible for ensuring that
// - no more than one goroutine calls the write methods
// NextWriter, SetWriteDeadline, WriteMessage, WriteJSON, EnableWriteCompression,
// SetCompressionLevel concurrently; and
// - that no more than one goroutine calls the
// read methods NextReader, SetReadDeadline, ReadMessage, ReadJSON, SetPongHandler,
// SetPingHandler concurrently.
//
// The Close and WriteControl methods can be called concurrently with all other methods.
type connWrapper struct {
conn *websocket.Conn
rlock sync.Mutex
wlock sync.Mutex
}
func newConnectionWrapper(conn *websocket.Conn) *connWrapper {
conn.SetReadLimit(messageSizeLimit)
return &connWrapper{conn: conn}
}
// WriteJSON wraps corresponding method on the websocket but is safe for concurrent calling
func (w *connWrapper) WriteJSON(v interface{}) error {
w.wlock.Lock()
defer w.wlock.Unlock()
return w.conn.WriteJSON(v)
}
// ReadJSON wraps corresponding method on the websocket but is safe for concurrent calling
func (w *connWrapper) ReadJSON(v interface{}) error {
w.rlock.Lock()
defer w.rlock.Unlock()
return w.conn.ReadJSON(v)
}
// Close wraps corresponding method on the websocket but is safe for concurrent calling
func (w *connWrapper) Close() error {
// The Close and WriteControl methods can be called concurrently with all other methods,
// so the mutex is not used here
return w.conn.Close()
}
// parseEthstatsURL parses the netstats connection url.
// URL argument should be of the form <nodename:secret@host:port>
// If non-erroring, the returned slice contains 3 elements: [nodename, pass, host]
func parseEthstatsURL(url string) (parts []string, err error) {
err = fmt.Errorf("invalid netstats url: \"%s\", should be nodename:secret@host:port", url)
hostIndex := strings.LastIndex(url, "@")
if hostIndex == -1 || hostIndex == len(url)-1 {
return nil, err
}
preHost, host := url[:hostIndex], url[hostIndex+1:]
passIndex := strings.LastIndex(preHost, ":")
if passIndex == -1 {
return []string{preHost, "", host}, nil
}
nodename, pass := preHost[:passIndex], ""
if passIndex != len(preHost)-1 {
pass = preHost[passIndex+1:]
}
return []string{nodename, pass, host}, nil
}
// New returns a monitoring service ready for stats reporting.
func New(node *node.Node, backend backend, engine consensus.Engine, url string) error {
parts, err := parseEthstatsURL(url)
if err != nil {
return err
}
ethstats := &Service{
backend: backend,
engine: engine,
server: node.Server(),
node: parts[0],
pass: parts[1],
host: parts[2],
pongCh: make(chan struct{}),
histCh: make(chan []uint64, 1),
}
node.RegisterLifecycle(ethstats)
return nil
}
// Start implements node.Lifecycle, starting up the monitoring and reporting daemon.
func (s *Service) Start() error {
// Subscribe to chain events to execute updates on
chainHeadCh := make(chan core.ChainHeadEvent, chainHeadChanSize)
s.headSub = s.backend.SubscribeChainHeadEvent(chainHeadCh)
txEventCh := make(chan core.NewTxsEvent, txChanSize)
s.txSub = s.backend.SubscribeNewTxsEvent(txEventCh)
go s.loop(chainHeadCh, txEventCh)
log.Info("Stats daemon started")
return nil
}
// Stop implements node.Lifecycle, terminating the monitoring and reporting daemon.
func (s *Service) Stop() error {
s.headSub.Unsubscribe()
s.txSub.Unsubscribe()
log.Info("Stats daemon stopped")
return nil
}
// loop keeps trying to connect to the netstats server, reporting chain events
// until termination.
func (s *Service) loop(chainHeadCh chan core.ChainHeadEvent, txEventCh chan core.NewTxsEvent) {
// Start a goroutine that exhausts the subscriptions to avoid events piling up
var (
quitCh = make(chan struct{})
headCh = make(chan *types.Block, 1)
txCh = make(chan struct{}, 1)
)
go func() {
var lastTx mclock.AbsTime
HandleLoop:
for {
select {
// Notify of chain head events, but drop if too frequent
case head := <-chainHeadCh:
select {
case headCh <- head.Block:
default:
}
// Notify of new transaction events, but drop if too frequent
case <-txEventCh:
if time.Duration(mclock.Now()-lastTx) < time.Second {
continue
}
lastTx = mclock.Now()
select {
case txCh <- struct{}{}:
default:
}
// node stopped
case <-s.txSub.Err():
break HandleLoop
case <-s.headSub.Err():
break HandleLoop
}
}
close(quitCh)
}()
// Resolve the URL, defaulting to TLS, but falling back to none too
path := fmt.Sprintf("%s/api", s.host)
urls := []string{path}
// url.Parse and url.IsAbs is unsuitable (https://github.com/golang/go/issues/19779)
if !strings.Contains(path, "://") {
urls = []string{"wss://" + path, "ws://" + path}
}
errTimer := time.NewTimer(0)
defer errTimer.Stop()
// Loop reporting until termination
for {
select {
case <-quitCh:
return
case <-errTimer.C:
// Establish a websocket connection to the server on any supported URL
var (
conn *connWrapper
err error
)
dialer := websocket.Dialer{HandshakeTimeout: 5 * time.Second}
header := make(http.Header)
header.Set("origin", "http://localhost")
for _, url := range urls {
c, _, e := dialer.Dial(url, header)
err = e
if err == nil {
conn = newConnectionWrapper(c)
break
}
}
if err != nil {
log.Warn("Stats server unreachable", "err", err)
errTimer.Reset(10 * time.Second)
continue
}
// Authenticate the client with the server
if err = s.login(conn); err != nil {
log.Warn("Stats login failed", "err", err)
conn.Close()
errTimer.Reset(10 * time.Second)
continue
}
go s.readLoop(conn)
// Send the initial stats so our node looks decent from the get go
if err = s.report(conn); err != nil {
log.Warn("Initial stats report failed", "err", err)
conn.Close()
errTimer.Reset(0)
continue
}
// Keep sending status updates until the connection breaks
fullReport := time.NewTicker(15 * time.Second)
for err == nil {
select {
case <-quitCh:
fullReport.Stop()
// Make sure the connection is closed
conn.Close()
return
case <-fullReport.C:
if err = s.report(conn); err != nil {
log.Warn("Full stats report failed", "err", err)
}
case list := <-s.histCh:
if err = s.reportHistory(conn, list); err != nil {
log.Warn("Requested history report failed", "err", err)
}
case head := <-headCh:
if err = s.reportBlock(conn, head); err != nil {
log.Warn("Block stats report failed", "err", err)
}
if err = s.reportPending(conn); err != nil {
log.Warn("Post-block transaction stats report failed", "err", err)
}
case <-txCh:
if err = s.reportPending(conn); err != nil {
log.Warn("Transaction stats report failed", "err", err)
}
}
}
fullReport.Stop()
// Close the current connection and establish a new one
conn.Close()
errTimer.Reset(0)
}
}
}
// readLoop loops as long as the connection is alive and retrieves data packets
// from the network socket. If any of them match an active request, it forwards
// it, if they themselves are requests it initiates a reply, and lastly it drops
// unknown packets.
func (s *Service) readLoop(conn *connWrapper) {
// If the read loop exits, close the connection
defer conn.Close()
for {
// Retrieve the next generic network packet and bail out on error
var blob json.RawMessage
if err := conn.ReadJSON(&blob); err != nil {
log.Warn("Failed to retrieve stats server message", "err", err)
return
}
// If the network packet is a system ping, respond to it directly
var ping string
if err := json.Unmarshal(blob, &ping); err == nil && strings.HasPrefix(ping, "primus::ping::") {
if err := conn.WriteJSON(strings.ReplaceAll(ping, "ping", "pong")); err != nil {
log.Warn("Failed to respond to system ping message", "err", err)
return
}
continue
}
// Not a system ping, try to decode an actual state message
var msg map[string][]interface{}
if err := json.Unmarshal(blob, &msg); err != nil {
log.Warn("Failed to decode stats server message", "err", err)
return
}
log.Trace("Received message from stats server", "msg", msg)
if len(msg["emit"]) == 0 {
log.Warn("Stats server sent non-broadcast", "msg", msg)
return
}
command, ok := msg["emit"][0].(string)
if !ok {
log.Warn("Invalid stats server message type", "type", msg["emit"][0])
return
}
// If the message is a ping reply, deliver (someone must be listening!)
if len(msg["emit"]) == 2 && command == "node-pong" {
select {
case s.pongCh <- struct{}{}:
// Pong delivered, continue listening
continue
default:
// Ping routine dead, abort
log.Warn("Stats server pinger seems to have died")
return
}
}
// If the message is a history request, forward to the event processor
if len(msg["emit"]) == 2 && command == "history" {
// Make sure the request is valid and doesn't crash us
request, ok := msg["emit"][1].(map[string]interface{})
if !ok {
log.Warn("Invalid stats history request", "msg", msg["emit"][1])
select {
case s.histCh <- nil: // Treat it as an no indexes request
default:
}
continue
}
list, ok := request["list"].([]interface{})
if !ok {
log.Warn("Invalid stats history block list", "list", request["list"])
return
}
// Convert the block number list to an integer list
numbers := make([]uint64, len(list))
for i, num := range list {
n, ok := num.(float64)
if !ok {
log.Warn("Invalid stats history block number", "number", num)
return
}
numbers[i] = uint64(n)
}
select {
case s.histCh <- numbers:
continue
default:
}
}
// Report anything else and continue
log.Info("Unknown stats message", "msg", msg)
}
}
// nodeInfo is the collection of meta information about a node that is displayed
// on the monitoring page.
type nodeInfo struct {
Name string `json:"name"`
Node string `json:"node"`
Port int `json:"port"`
Network string `json:"net"`
Protocol string `json:"protocol"`
API string `json:"api"`
Os string `json:"os"`
OsVer string `json:"os_v"`
Client string `json:"client"`
History bool `json:"canUpdateHistory"`
}
// authMsg is the authentication infos needed to login to a monitoring server.
type authMsg struct {
ID string `json:"id"`
Info nodeInfo `json:"info"`
Secret string `json:"secret"`
}
// login tries to authorize the client at the remote server.
func (s *Service) login(conn *connWrapper) error {
// Construct and send the login authentication
infos := s.server.NodeInfo()
var protocols []string
for _, proto := range s.server.Protocols {
protocols = append(protocols, fmt.Sprintf("%s/%d", proto.Name, proto.Version))
}
var network string
if info := infos.Protocols["eth"]; info != nil {
network = fmt.Sprintf("%d", info.(*ethproto.NodeInfo).Network)
} else {
network = fmt.Sprintf("%d", infos.Protocols["les"].(*les.NodeInfo).Network)
}
auth := &authMsg{
ID: s.node,
Info: nodeInfo{
Name: s.node,
Node: infos.Name,
Port: infos.Ports.Listener,
Network: network,
Protocol: strings.Join(protocols, ", "),
API: "No",
Os: runtime.GOOS,
OsVer: runtime.GOARCH,
Client: "0.1.1",
History: true,
},
Secret: s.pass,
}
login := map[string][]interface{}{
"emit": {"hello", auth},
}
if err := conn.WriteJSON(login); err != nil {
return err
}
// Retrieve the remote ack or connection termination
var ack map[string][]string
if err := conn.ReadJSON(&ack); err != nil || len(ack["emit"]) != 1 || ack["emit"][0] != "ready" {
return errors.New("unauthorized")
}
return nil
}
// report collects all possible data to report and send it to the stats server.
// This should only be used on reconnects or rarely to avoid overloading the
// server. Use the individual methods for reporting subscribed events.
func (s *Service) report(conn *connWrapper) error {
if err := s.reportLatency(conn); err != nil {
return err
}
if err := s.reportBlock(conn, nil); err != nil {
return err
}
if err := s.reportPending(conn); err != nil {
return err
}
if err := s.reportStats(conn); err != nil {
return err
}
return nil
}
// reportLatency sends a ping request to the server, measures the RTT time and
// finally sends a latency update.
func (s *Service) reportLatency(conn *connWrapper) error {
// Send the current time to the ethstats server
start := time.Now()
ping := map[string][]interface{}{
"emit": {"node-ping", map[string]string{
"id": s.node,
"clientTime": start.String(),
}},
}
if err := conn.WriteJSON(ping); err != nil {
return err
}
// Wait for the pong request to arrive back
select {
case <-s.pongCh:
// Pong delivered, report the latency
case <-time.After(5 * time.Second):
// Ping timeout, abort
return errors.New("ping timed out")
}
latency := strconv.Itoa(int((time.Since(start) / time.Duration(2)).Nanoseconds() / 1000000))
// Send back the measured latency
log.Trace("Sending measured latency to ethstats", "latency", latency)
stats := map[string][]interface{}{
"emit": {"latency", map[string]string{
"id": s.node,
"latency": latency,
}},
}
return conn.WriteJSON(stats)
}
// blockStats is the information to report about individual blocks.
type blockStats struct {
Number *big.Int `json:"number"`
Hash common.Hash `json:"hash"`
ParentHash common.Hash `json:"parentHash"`
Timestamp *big.Int `json:"timestamp"`
Miner common.Address `json:"miner"`
GasUsed uint64 `json:"gasUsed"`
GasLimit uint64 `json:"gasLimit"`
Diff string `json:"difficulty"`
TotalDiff string `json:"totalDifficulty"`
Txs []txStats `json:"transactions"`
TxHash common.Hash `json:"transactionsRoot"`
Root common.Hash `json:"stateRoot"`
Uncles uncleStats `json:"uncles"`
}
// txStats is the information to report about individual transactions.
type txStats struct {
Hash common.Hash `json:"hash"`
}
// uncleStats is a custom wrapper around an uncle array to force serializing
// empty arrays instead of returning null for them.
type uncleStats []*types.Header
func (s uncleStats) MarshalJSON() ([]byte, error) {
if uncles := ([]*types.Header)(s); len(uncles) > 0 {
return json.Marshal(uncles)
}
return []byte("[]"), nil
}
// reportBlock retrieves the current chain head and reports it to the stats server.
func (s *Service) reportBlock(conn *connWrapper, block *types.Block) error {
// Gather the block details from the header or block chain
details := s.assembleBlockStats(block)
// Assemble the block report and send it to the server
log.Trace("Sending new block to ethstats", "number", details.Number, "hash", details.Hash)
stats := map[string]interface{}{
"id": s.node,
"block": details,
}
report := map[string][]interface{}{
"emit": {"block", stats},
}
return conn.WriteJSON(report)
}
// assembleBlockStats retrieves any required metadata to report a single block
// and assembles the block stats. If block is nil, the current head is processed.
func (s *Service) assembleBlockStats(block *types.Block) *blockStats {
// Gather the block infos from the local blockchain
var (
header *types.Header
td *big.Int
txs []txStats
uncles []*types.Header
)
// check if backend is a full node
fullBackend, ok := s.backend.(fullNodeBackend)
if ok {
if block == nil {
block = fullBackend.CurrentBlock()
}
header = block.Header()
td = fullBackend.GetTd(context.Background(), header.Hash())
txs = make([]txStats, len(block.Transactions()))
for i, tx := range block.Transactions() {
txs[i].Hash = tx.Hash()
}
uncles = block.Uncles()
} else {
// Light nodes would need on-demand lookups for transactions/uncles, skip
if block != nil {
header = block.Header()
} else {
header = s.backend.CurrentHeader()
}
td = s.backend.GetTd(context.Background(), header.Hash())
txs = []txStats{}
}
// Assemble and return the block stats
author, _ := s.engine.Author(header)
return &blockStats{
Number: header.Number,
Hash: header.Hash(),
ParentHash: header.ParentHash,
Timestamp: new(big.Int).SetUint64(header.Time),
Miner: author,
GasUsed: header.GasUsed,
GasLimit: header.GasLimit,
Diff: header.Difficulty.String(),
TotalDiff: td.String(),
Txs: txs,
TxHash: header.TxHash,
Root: header.Root,
Uncles: uncles,
}
}
// reportHistory retrieves the most recent batch of blocks and reports it to the
// stats server.
func (s *Service) reportHistory(conn *connWrapper, list []uint64) error {
// Figure out the indexes that need reporting
indexes := make([]uint64, 0, historyUpdateRange)
if len(list) > 0 {
// Specific indexes requested, send them back in particular
indexes = append(indexes, list...)
} else {
// No indexes requested, send back the top ones
head := s.backend.CurrentHeader().Number.Int64()
start := head - historyUpdateRange + 1
if start < 0 {
start = 0
}
for i := uint64(start); i <= uint64(head); i++ {
indexes = append(indexes, i)
}
}
// Gather the batch of blocks to report
history := make([]*blockStats, len(indexes))
for i, number := range indexes {
fullBackend, ok := s.backend.(fullNodeBackend)
// Retrieve the next block if it's known to us
var block *types.Block
if ok {
block, _ = fullBackend.BlockByNumber(context.Background(), rpc.BlockNumber(number)) // TODO ignore error here ?
} else {
if header, _ := s.backend.HeaderByNumber(context.Background(), rpc.BlockNumber(number)); header != nil {
block = types.NewBlockWithHeader(header)
}
}
// If we do have the block, add to the history and continue
if block != nil {
history[len(history)-1-i] = s.assembleBlockStats(block)
continue
}
// Ran out of blocks, cut the report short and send
history = history[len(history)-i:]
break
}
// Assemble the history report and send it to the server
if len(history) > 0 {
log.Trace("Sending historical blocks to ethstats", "first", history[0].Number, "last", history[len(history)-1].Number)
} else {
log.Trace("No history to send to stats server")
}
stats := map[string]interface{}{
"id": s.node,
"history": history,
}
report := map[string][]interface{}{
"emit": {"history", stats},
}
return conn.WriteJSON(report)
}
// pendStats is the information to report about pending transactions.
type pendStats struct {
Pending int `json:"pending"`
}
// reportPending retrieves the current number of pending transactions and reports
// it to the stats server.
func (s *Service) reportPending(conn *connWrapper) error {
// Retrieve the pending count from the local blockchain
pending, _ := s.backend.Stats()
// Assemble the transaction stats and send it to the server
log.Trace("Sending pending transactions to ethstats", "count", pending)
stats := map[string]interface{}{
"id": s.node,
"stats": &pendStats{
Pending: pending,
},
}
report := map[string][]interface{}{
"emit": {"pending", stats},
}
return conn.WriteJSON(report)
}
// nodeStats is the information to report about the local node.
type nodeStats struct {
Active bool `json:"active"`
Syncing bool `json:"syncing"`
Mining bool `json:"mining"`
Hashrate int `json:"hashrate"`
Peers int `json:"peers"`
GasPrice int `json:"gasPrice"`
Uptime int `json:"uptime"`
}
// reportStats retrieves various stats about the node at the networking and
// mining layer and reports it to the stats server.
func (s *Service) reportStats(conn *connWrapper) error {
// Gather the syncing and mining infos from the local miner instance
var (
mining bool
hashrate int
syncing bool
gasprice int
)
// check if backend is a full node
fullBackend, ok := s.backend.(fullNodeBackend)
if ok {
mining = fullBackend.Miner().Mining()
hashrate = int(fullBackend.Miner().Hashrate())
sync := fullBackend.SyncProgress()
syncing = fullBackend.CurrentHeader().Number.Uint64() >= sync.HighestBlock
price, _ := fullBackend.SuggestGasTipCap(context.Background())
gasprice = int(price.Uint64())
if basefee := fullBackend.CurrentHeader().BaseFee; basefee != nil {
gasprice += int(basefee.Uint64())
}
} else {
sync := s.backend.SyncProgress()
syncing = s.backend.CurrentHeader().Number.Uint64() >= sync.HighestBlock
}
// Assemble the node stats and send it to the server
log.Trace("Sending node details to ethstats")
stats := map[string]interface{}{
"id": s.node,
"stats": &nodeStats{
Active: true,
Mining: mining,
Hashrate: hashrate,
Peers: s.server.PeerCount(),
GasPrice: gasprice,
Syncing: syncing,
Uptime: 100,
},
}
report := map[string][]interface{}{
"emit": {"stats", stats},
}
return conn.WriteJSON(report)
}