open-nomad/command/agent/keyring.go

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package agent
import (
"encoding/base64"
"encoding/json"
"fmt"
"io/ioutil"
"os"
"path/filepath"
"github.com/hashicorp/memberlist"
"github.com/hashicorp/serf/serf"
)
const (
serfKeyring = "server/serf.keyring"
)
// initKeyring will create a keyring file at a given path.
func initKeyring(path, key string) error {
var keys []string
if keyBytes, err := base64.StdEncoding.DecodeString(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
}
// Read in the keyring file data
keyringData, err := ioutil.ReadFile(c.KeyringFile)
if err != nil {
return err
}
// Decode keyring JSON
keys := make([]string, 0)
if err := json.Unmarshal(keyringData, &keys); err != nil {
return err
}
// Decode base64 values
keysDecoded := make([][]byte, len(keys))
for i, key := range keys {
keyBytes, err := base64.StdEncoding.DecodeString(key)
if err != nil {
return err
}
keysDecoded[i] = keyBytes
}
// Guard against empty keyring
if len(keysDecoded) == 0 {
return fmt.Errorf("no keys present in keyring file: %s", c.KeyringFile)
}
// Create the keyring
keyring, err := memberlist.NewKeyring(keysDecoded, keysDecoded[0])
if err != nil {
return err
}
c.MemberlistConfig.Keyring = keyring
// Success!
return nil
}