open-consul/agent/keyring.go

311 lines
8.5 KiB
Go

package agent
import (
"bytes"
"encoding/base64"
"encoding/json"
"fmt"
"io/ioutil"
"os"
"path/filepath"
"github.com/hashicorp/consul/agent/config"
"github.com/hashicorp/consul/agent/consul"
"github.com/hashicorp/consul/agent/structs"
"github.com/hashicorp/go-hclog"
"github.com/hashicorp/memberlist"
"github.com/hashicorp/serf/serf"
)
const (
SerfLANKeyring = "serf/local.keyring"
SerfWANKeyring = "serf/remote.keyring"
)
// setupKeyrings in config.SerfLANConfig and config.SerfWANConfig.
func setupKeyrings(config *consul.Config, rtConfig *config.RuntimeConfig, logger hclog.Logger) error {
// First set up the LAN and WAN keyrings.
if err := setupBaseKeyrings(config, rtConfig, logger); err != nil {
return err
}
// If there's no LAN keyring then there's nothing else to set up for
// any segments.
lanKeyring := config.SerfLANConfig.MemberlistConfig.Keyring
if lanKeyring == nil {
return nil
}
// Copy the initial state of the LAN keyring into each segment config.
// Segments don't have their own keyring file, they rely on the LAN
// holding the state so things can't get out of sync.
k, pk := lanKeyring.GetKeys(), lanKeyring.GetPrimaryKey()
for _, segment := range config.Segments {
keyring, err := memberlist.NewKeyring(k, pk)
if err != nil {
return err
}
segment.SerfConfig.MemberlistConfig.Keyring = keyring
}
return nil
}
// setupBaseKeyrings configures the LAN and WAN keyrings.
func setupBaseKeyrings(config *consul.Config, rtConfig *config.RuntimeConfig, logger hclog.Logger) error {
// If the keyring file is disabled then just poke the provided key
// into the in-memory keyring.
federationEnabled := config.SerfWANConfig != nil
if rtConfig.DisableKeyringFile {
if rtConfig.EncryptKey == "" {
return nil
}
keys := []string{rtConfig.EncryptKey}
if err := loadKeyring(config.SerfLANConfig, keys); err != nil {
return err
}
if rtConfig.ServerMode && federationEnabled {
if err := loadKeyring(config.SerfWANConfig, keys); err != nil {
return err
}
}
return nil
}
// Otherwise, we need to deal with the keyring files.
fileLAN := filepath.Join(rtConfig.DataDir, SerfLANKeyring)
fileWAN := filepath.Join(rtConfig.DataDir, SerfWANKeyring)
var existingLANKeyring, existingWANKeyring bool
if rtConfig.EncryptKey == "" {
goto LOAD
}
if _, err := os.Stat(fileLAN); err != nil {
if err := initKeyring(fileLAN, rtConfig.EncryptKey); err != nil {
return err
}
} else {
existingLANKeyring = true
}
if rtConfig.ServerMode && federationEnabled {
if _, err := os.Stat(fileWAN); err != nil {
if err := initKeyring(fileWAN, rtConfig.EncryptKey); err != nil {
return err
}
} else {
existingWANKeyring = true
}
}
LOAD:
if _, err := os.Stat(fileLAN); err == nil {
config.SerfLANConfig.KeyringFile = fileLAN
}
if err := loadKeyringFile(config.SerfLANConfig); err != nil {
return err
}
if rtConfig.ServerMode && federationEnabled {
if _, err := os.Stat(fileWAN); err == nil {
config.SerfWANConfig.KeyringFile = fileWAN
}
if err := loadKeyringFile(config.SerfWANConfig); err != nil {
return err
}
}
// Only perform the following checks if there was an encrypt_key
// provided in the configuration.
if rtConfig.EncryptKey != "" {
msg := " keyring doesn't include key provided with -encrypt, using keyring"
if existingLANKeyring &&
keyringIsMissingKey(
config.SerfLANConfig.MemberlistConfig.Keyring,
rtConfig.EncryptKey,
) {
logger.Warn(msg, "keyring", "LAN")
}
if existingWANKeyring &&
keyringIsMissingKey(
config.SerfWANConfig.MemberlistConfig.Keyring,
rtConfig.EncryptKey,
) {
logger.Warn(msg, "keyring", "WAN")
}
}
return nil
}
// initKeyring will create a keyring file at a given path.
func initKeyring(path, key string) error {
var keys []string
if keyBytes, err := decodeStringKey(key); err != nil {
return fmt.Errorf("Invalid key: %s", err)
} else if err := memberlist.ValidateKey(keyBytes); err != nil {
return fmt.Errorf("Invalid key: %s", err)
}
// Just exit if the file already exists.
if _, err := os.Stat(path); err == nil {
return nil
}
keys = append(keys, key)
keyringBytes, err := json.Marshal(keys)
if err != nil {
return err
}
if err := os.MkdirAll(filepath.Dir(path), 0700); err != nil {
return err
}
fh, err := os.OpenFile(path, os.O_CREATE|os.O_WRONLY|os.O_TRUNC, 0600)
if err != nil {
return err
}
defer fh.Close()
if _, err := fh.Write(keyringBytes); err != nil {
os.Remove(path)
return err
}
return nil
}
// loadKeyringFile will load a gossip encryption keyring out of a file. The file
// must be in JSON format and contain a list of encryption key strings.
func loadKeyringFile(c *serf.Config) error {
if c.KeyringFile == "" {
return nil
}
if _, err := os.Stat(c.KeyringFile); err != nil {
return err
}
keyringData, err := ioutil.ReadFile(c.KeyringFile)
if err != nil {
return err
}
keys := make([]string, 0)
if err := json.Unmarshal(keyringData, &keys); err != nil {
return err
}
return loadKeyring(c, keys)
}
// loadKeyring takes a list of base64-encoded strings and installs them in the
// given Serf's keyring.
func loadKeyring(c *serf.Config, keys []string) error {
keysDecoded := make([][]byte, len(keys))
for i, key := range keys {
keyBytes, err := decodeStringKey(key)
if err != nil {
return err
}
keysDecoded[i] = keyBytes
}
if len(keysDecoded) == 0 {
return fmt.Errorf("no keys present in keyring: %s", c.KeyringFile)
}
keyring, err := memberlist.NewKeyring(keysDecoded, keysDecoded[0])
if err != nil {
return err
}
c.MemberlistConfig.Keyring = keyring
return nil
}
func decodeStringKey(key string) ([]byte, error) {
return base64.StdEncoding.DecodeString(key)
}
// keyringProcess is used to abstract away the semantic similarities in
// performing various operations on the encryption keyring.
func (a *Agent) keyringProcess(args *structs.KeyringRequest) (*structs.KeyringResponses, error) {
var reply structs.KeyringResponses
if _, ok := a.delegate.(*consul.Server); !ok {
return nil, fmt.Errorf("keyring operations must run against a server node")
}
if err := a.RPC("Internal.KeyringOperation", args, &reply); err != nil {
return &reply, err
}
return &reply, nil
}
// ParseRelayFactor validates and converts the given relay factor to uint8
func ParseRelayFactor(n int) (uint8, error) {
if n < 0 || n > 5 {
return 0, fmt.Errorf("Relay factor must be in range: [0, 5]")
}
return uint8(n), nil
}
// ValidateLocalOnly validates the local-only flag, requiring that it only be
// set for list requests.
func ValidateLocalOnly(local bool, list bool) error {
if local && !list {
return fmt.Errorf("local-only can only be set for list requests")
}
return nil
}
// ListKeys lists out all keys installed on the collective Consul cluster. This
// includes both servers and clients in all DC's.
func (a *Agent) ListKeys(token string, localOnly bool, relayFactor uint8) (*structs.KeyringResponses, error) {
args := structs.KeyringRequest{Operation: structs.KeyringList, LocalOnly: localOnly}
parseKeyringRequest(&args, token, relayFactor)
return a.keyringProcess(&args)
}
// InstallKey installs a new gossip encryption key
func (a *Agent) InstallKey(key, token string, relayFactor uint8) (*structs.KeyringResponses, error) {
args := structs.KeyringRequest{Key: key, Operation: structs.KeyringInstall}
parseKeyringRequest(&args, token, relayFactor)
return a.keyringProcess(&args)
}
// UseKey changes the primary encryption key used to encrypt messages
func (a *Agent) UseKey(key, token string, relayFactor uint8) (*structs.KeyringResponses, error) {
args := structs.KeyringRequest{Key: key, Operation: structs.KeyringUse}
parseKeyringRequest(&args, token, relayFactor)
return a.keyringProcess(&args)
}
// RemoveKey will remove a gossip encryption key from the keyring
func (a *Agent) RemoveKey(key, token string, relayFactor uint8) (*structs.KeyringResponses, error) {
args := structs.KeyringRequest{Key: key, Operation: structs.KeyringRemove}
parseKeyringRequest(&args, token, relayFactor)
return a.keyringProcess(&args)
}
func parseKeyringRequest(req *structs.KeyringRequest, token string, relayFactor uint8) {
req.Token = token
req.RelayFactor = relayFactor
}
// keyringIsMissingKey checks whether a key is part of a keyring. Returns true
// if it is not included.
func keyringIsMissingKey(keyring *memberlist.Keyring, key string) bool {
k1, err := decodeStringKey(key)
if err != nil {
return true
}
for _, k2 := range keyring.GetKeys() {
if bytes.Equal(k1, k2) {
return false
}
}
return true
}