lbcwallet/rpcserver.go
Josh Rickmar 567752ea9b Add option for one time TLS keys.
This option prevents the RPC server TLS key from ever being written to
disk.  This is performed by generating a new certificate pair each
startup and writing (possibly overwriting) the certificate but not the
key.

Closes #359.
2016-02-11 00:15:30 -05:00

265 lines
8.5 KiB
Go

/*
* Copyright (c) 2013-2015 The btcsuite developers
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
package main
import (
"crypto/tls"
"errors"
"fmt"
"io/ioutil"
"net"
"os"
"path/filepath"
"runtime"
"strings"
"time"
"github.com/btcsuite/btcutil"
"github.com/btcsuite/btcwallet/rpc/legacyrpc"
"github.com/btcsuite/btcwallet/rpc/rpcserver"
"github.com/btcsuite/btcwallet/wallet"
"google.golang.org/grpc"
"google.golang.org/grpc/credentials"
)
// openRPCKeyPair creates or loads the RPC TLS keypair specified by the
// application config. This function respects the cfg.OneTimeTLSKey setting.
func openRPCKeyPair() (tls.Certificate, error) {
// Check for existence of the TLS key file. If one time TLS keys are
// enabled but a key already exists, this function should error since
// it's possible that a persistent certificate was copied to a remote
// machine. Otherwise, generate a new keypair when the key is missing.
// When generating new persistent keys, overwriting an existing cert is
// acceptable if the previous execution used a one time TLS key.
// Otherwise, both the cert and key should be read from disk. If the
// cert is missing, the read error will occur in LoadX509KeyPair.
_, e := os.Stat(cfg.RPCKey)
keyExists := !os.IsNotExist(e)
switch {
case cfg.OneTimeTLSKey && keyExists:
err := fmt.Errorf("one time TLS keys are enabled, but TLS key "+
"`%s` already exists", cfg.RPCKey)
return tls.Certificate{}, err
case cfg.OneTimeTLSKey:
return generateRPCKeyPair(false)
case !keyExists:
return generateRPCKeyPair(true)
default:
return tls.LoadX509KeyPair(cfg.RPCCert, cfg.RPCKey)
}
}
// generateRPCKeyPair generates a new RPC TLS keypair and writes the cert and
// possibly also the key in PEM format to the paths specified by the config. If
// successful, the new keypair is returned.
func generateRPCKeyPair(writeKey bool) (tls.Certificate, error) {
log.Infof("Generating TLS certificates...")
// Create directories for cert and key files if they do not yet exist.
certDir, _ := filepath.Split(cfg.RPCCert)
keyDir, _ := filepath.Split(cfg.RPCKey)
err := os.MkdirAll(certDir, 0700)
if err != nil {
return tls.Certificate{}, err
}
err = os.MkdirAll(keyDir, 0700)
if err != nil {
return tls.Certificate{}, err
}
// Generate cert pair.
org := "btcwallet autogenerated cert"
validUntil := time.Now().Add(time.Hour * 24 * 365 * 10)
cert, key, err := btcutil.NewTLSCertPair(org, validUntil, nil)
if err != nil {
return tls.Certificate{}, err
}
keyPair, err := tls.X509KeyPair(cert, key)
if err != nil {
return tls.Certificate{}, err
}
// Write cert and (potentially) the key files.
err = ioutil.WriteFile(cfg.RPCCert, cert, 0600)
if err != nil {
return tls.Certificate{}, err
}
if writeKey {
err = ioutil.WriteFile(cfg.RPCKey, key, 0600)
if err != nil {
rmErr := os.Remove(cfg.RPCCert)
if rmErr != nil {
log.Warnf("Cannot remove written certificates: %v",
rmErr)
}
return tls.Certificate{}, err
}
}
log.Info("Done generating TLS certificates")
return keyPair, nil
}
func startRPCServers(walletLoader *wallet.Loader) (*grpc.Server, *legacyrpc.Server, error) {
var (
server *grpc.Server
legacyServer *legacyrpc.Server
legacyListen = net.Listen
keyPair tls.Certificate
err error
)
if cfg.DisableServerTLS {
log.Info("Server TLS is disabled. Only legacy RPC may be used")
} else {
keyPair, err = openRPCKeyPair()
if err != nil {
return nil, nil, err
}
// Change the standard net.Listen function to the tls one.
tlsConfig := &tls.Config{
Certificates: []tls.Certificate{keyPair},
MinVersion: tls.VersionTLS12,
NextProtos: []string{"h2"}, // HTTP/2 over TLS
}
legacyListen = func(net string, laddr string) (net.Listener, error) {
return tls.Listen(net, laddr, tlsConfig)
}
if len(cfg.ExperimentalRPCListeners) != 0 {
listeners := makeListeners(cfg.ExperimentalRPCListeners, net.Listen)
if len(listeners) == 0 {
err := errors.New("failed to create listeners for RPC server")
return nil, nil, err
}
creds := credentials.NewServerTLSFromCert(&keyPair)
server = grpc.NewServer(grpc.Creds(creds))
rpcserver.StartWalletLoaderService(server, walletLoader, activeNet)
for _, lis := range listeners {
lis := lis
go func() {
log.Infof("Experimental RPC server listening on %s",
lis.Addr())
err := server.Serve(lis)
log.Tracef("Finished serving expimental RPC: %v",
err)
}()
}
}
}
if cfg.Username == "" || cfg.Password == "" {
log.Info("Legacy RPC server disabled (requires username and password)")
} else if len(cfg.LegacyRPCListeners) != 0 {
listeners := makeListeners(cfg.LegacyRPCListeners, legacyListen)
if len(listeners) == 0 {
err := errors.New("failed to create listeners for legacy RPC server")
return nil, nil, err
}
opts := legacyrpc.Options{
Username: cfg.Username,
Password: cfg.Password,
MaxPOSTClients: cfg.LegacyRPCMaxClients,
MaxWebsocketClients: cfg.LegacyRPCMaxWebsockets,
}
legacyServer = legacyrpc.NewServer(&opts, walletLoader, listeners)
}
// Error when neither the GRPC nor legacy RPC servers can be started.
if server == nil && legacyServer == nil {
return nil, nil, errors.New("no suitable RPC services can be started")
}
return server, legacyServer, nil
}
type listenFunc func(net string, laddr string) (net.Listener, error)
// makeListeners splits the normalized listen addresses into IPv4 and IPv6
// addresses and creates new net.Listeners for each with the passed listen func.
// Invalid addresses are logged and skipped.
func makeListeners(normalizedListenAddrs []string, listen listenFunc) []net.Listener {
ipv4Addrs := make([]string, 0, len(normalizedListenAddrs)*2)
ipv6Addrs := make([]string, 0, len(normalizedListenAddrs)*2)
for _, addr := range normalizedListenAddrs {
host, _, err := net.SplitHostPort(addr)
if err != nil {
// Shouldn't happen due to already being normalized.
log.Errorf("`%s` is not a normalized "+
"listener address", addr)
continue
}
// Empty host or host of * on plan9 is both IPv4 and IPv6.
if host == "" || (host == "*" && runtime.GOOS == "plan9") {
ipv4Addrs = append(ipv4Addrs, addr)
ipv6Addrs = append(ipv6Addrs, addr)
continue
}
// Remove the IPv6 zone from the host, if present. The zone
// prevents ParseIP from correctly parsing the IP address.
// ResolveIPAddr is intentionally not used here due to the
// possibility of leaking a DNS query over Tor if the host is a
// hostname and not an IP address.
zoneIndex := strings.Index(host, "%")
if zoneIndex != -1 {
host = host[:zoneIndex]
}
ip := net.ParseIP(host)
switch {
case ip == nil:
log.Warnf("`%s` is not a valid IP address", host)
case ip.To4() == nil:
ipv6Addrs = append(ipv6Addrs, addr)
default:
ipv4Addrs = append(ipv4Addrs, addr)
}
}
listeners := make([]net.Listener, 0, len(ipv6Addrs)+len(ipv4Addrs))
for _, addr := range ipv4Addrs {
listener, err := listen("tcp4", addr)
if err != nil {
log.Warnf("Can't listen on %s: %v", addr, err)
continue
}
listeners = append(listeners, listener)
}
for _, addr := range ipv6Addrs {
listener, err := listen("tcp6", addr)
if err != nil {
log.Warnf("Can't listen on %s: %v", addr, err)
continue
}
listeners = append(listeners, listener)
}
return listeners
}
// startWalletRPCServices associates each of the (optionally-nil) RPC servers
// with a wallet to enable remote wallet access. For the GRPC server, this
// registers the WalletService service, and for the legacy JSON-RPC server it
// enables methods that require a loaded wallet.
func startWalletRPCServices(wallet *wallet.Wallet, server *grpc.Server, legacyServer *legacyrpc.Server) {
if server != nil {
rpcserver.StartWalletService(server, wallet)
}
if legacyServer != nil {
legacyServer.RegisterWallet(wallet)
}
}