cmd/ethkey: add command to change key passphrase (ethereum#16516)

This change introduces 

    ethkey changepassphrase <keyfile>

to change the passphrase of a key file.

cmd/ethkey/changepassphrase.go

@@ -0,0 +1,72 @@
+package main
+
+import (
+ "fmt"
+ "io/ioutil"
+ "strings"
+
+ "github.com/ethereum/go-ethereum/accounts/keystore"
+ "github.com/ethereum/go-ethereum/cmd/utils"
+ "gopkg.in/urfave/cli.v1"
+)
+
+var newPassphraseFlag = cli.StringFlag{
+ Name: "newpasswordfile",
+ Usage: "the file that contains the new passphrase for the keyfile",
+}
+
+var commandChangePassphrase = cli.Command{
+ Name: "changepassphrase",
+ Usage: "change the passphrase on a keyfile",
+ ArgsUsage: "<keyfile>",
+ Description: `
+Change the passphrase of a keyfile.`,
+ Flags: []cli.Flag{
+ passphraseFlag,
+ newPassphraseFlag,
+ },
+ Action: func(ctx *cli.Context) error {
+ keyfilepath := ctx.Args().First()
+
+ // Read key from file.
+ keyjson, err := ioutil.ReadFile(keyfilepath)
+ if err != nil {
+ utils.Fatalf("Failed to read the keyfile at '%s': %v", keyfilepath, err)
+ }
+
+ // Decrypt key with passphrase.
+ passphrase := getPassphrase(ctx)
+ key, err := keystore.DecryptKey(keyjson, passphrase)
+ if err != nil {
+ utils.Fatalf("Error decrypting key: %v", err)
+ }
+
+ // Get a new passphrase.
+ fmt.Println("Please provide a new passphrase")
+ var newPhrase string
+ if passFile := ctx.String(newPassphraseFlag.Name); passFile != "" {
+ content, err := ioutil.ReadFile(passFile)
+ if err != nil {
+ utils.Fatalf("Failed to read new passphrase file '%s': %v", passFile, err)
+ }
+ newPhrase = strings.TrimRight(string(content), "\r\n")
+ } else {
+ newPhrase = promptPassphrase(true)
+ }
+
+ // Encrypt the key with the new passphrase.
+ newJson, err := keystore.EncryptKey(key, newPhrase, keystore.StandardScryptN, keystore.StandardScryptP)
+ if err != nil {
+ utils.Fatalf("Error encrypting with new passphrase: %v", err)
+ }
+
+ // Then write the new keyfile in place of the old one.
+ if err := ioutil.WriteFile(keyfilepath, newJson, 600); err != nil {
+ utils.Fatalf("Error writing new keyfile to disk: %v", err)
+ }
+
+ // Don't print anything. Just return successfully,
+ // producing a positive exit code.
+ return nil
+ },
+}

cmd/ethkey/generate.go

@@ -90,7 +90,7 @@ If you want to encrypt an existing private key, it can be specified by setting
  }
 
  // Encrypt key with passphrase.
- passphrase := getPassPhrase(ctx, true)
+ passphrase := promptPassphrase(true)
  keyjson, err := keystore.EncryptKey(key, passphrase, keystore.StandardScryptN, keystore.StandardScryptP)
  if err != nil {
  utils.Fatalf("Error encrypting key: %v", err)

cmd/ethkey/inspect.go

@@ -60,7 +60,7 @@ make sure to use this feature with great caution!`,
  }
 
  // Decrypt key with passphrase.
- passphrase := getPassPhrase(ctx, false)
+ passphrase := getPassphrase(ctx)
  key, err := keystore.DecryptKey(keyjson, passphrase)
  if err != nil {
  utils.Fatalf("Error decrypting key: %v", err)

cmd/ethkey/main.go

@@ -38,6 +38,7 @@ func init() {
  app.Commands = []cli.Command{
  commandGenerate,
  commandInspect,
+ commandChangePassphrase,
  commandSignMessage,
  commandVerifyMessage,
  }

cmd/ethkey/message.go

@@ -62,7 +62,7 @@ To sign a message contained in a file, use the --msgfile flag.
  }
 
  // Decrypt key with passphrase.
- passphrase := getPassPhrase(ctx, false)
+ passphrase := getPassphrase(ctx)
  key, err := keystore.DecryptKey(keyjson, passphrase)
  if err != nil {
  utils.Fatalf("Error decrypting key: %v", err)

cmd/ethkey/utils.go

@@ -28,26 +28,14 @@ import (
  "gopkg.in/urfave/cli.v1"
 )
 
-// getPassPhrase obtains a passphrase given by the user. It first checks the
-// --passphrase command line flag and ultimately prompts the user for a
-// passphrase.
-func getPassPhrase(ctx *cli.Context, confirmation bool) string {
- // Look for the --passphrase flag.
- passphraseFile := ctx.String(passphraseFlag.Name)
- if passphraseFile != "" {
- content, err := ioutil.ReadFile(passphraseFile)
- if err != nil {
- utils.Fatalf("Failed to read passphrase file '%s': %v",
- passphraseFile, err)
- }
- return strings.TrimRight(string(content), "\r\n")
- }
-
- // Otherwise prompt the user for the passphrase.
+// promptPassphrase prompts the user for a passphrase. Set confirmation to true
+// to require the user to confirm the passphrase.
+func promptPassphrase(confirmation bool) string {
  passphrase, err := console.Stdin.PromptPassword("Passphrase: ")
  if err != nil {
  utils.Fatalf("Failed to read passphrase: %v", err)
  }
+
  if confirmation {
  confirm, err := console.Stdin.PromptPassword("Repeat passphrase: ")
  if err != nil {
@@ -57,9 +45,29 @@ func getPassPhrase(ctx *cli.Context, confirmation bool) string {
  utils.Fatalf("Passphrases do not match")
  }
  }
+
  return passphrase
 }
 
+// getPassphrase obtains a passphrase given by the user. It first checks the
+// --passfile command line flag and ultimately prompts the user for a
+// passphrase.
+func getPassphrase(ctx *cli.Context) string {
+ // Look for the --passwordfile flag.
+ passphraseFile := ctx.String(passphraseFlag.Name)
+ if passphraseFile != "" {
+ content, err := ioutil.ReadFile(passphraseFile)
+ if err != nil {
+ utils.Fatalf("Failed to read passphrase file '%s': %v",
+ passphraseFile, err)
+ }
+ return strings.TrimRight(string(content), "\r\n")
+ }
+
+ // Otherwise prompt the user for the passphrase.
+ return promptPassphrase(false)
+}
+
 // signHash is a helper function that calculates a hash for the given message
 // that can be safely used to calculate a signature from.
 //