vspadmin: Add retirexpub command.

The new command opens an existing vspd database and replaces the
currently used xpub with a new one.

Author: jholdstock

cmd/vspadmin/README.md

@@ -38,3 +38,17 @@ Example:
 ```no-highlight
 $ go run ./cmd/vspadmin writeconfig
 ```
+
+### `retirexpub`
+
+Replaces the currently used xpub with a new one. Once an xpub key has been
+retired it can not be used by the VSP again.
+
+**Note:** vspd must be stopped before this command can be used because it
+modifies values in the vspd database.
+
+Example:
+
+```no-highlight
+$ go run ./cmd/vspadmin retirexpub <xpub>
+```

cmd/vspadmin/main.go

@@ -12,6 +12,7 @@ import (
 
 	"github.com/decred/dcrd/dcrutil/v4"
 	"github.com/decred/dcrd/hdkeychain/v3"
+	"github.com/decred/slog"
 	"github.com/decred/vspd/database"
 	"github.com/decred/vspd/internal/config"
 	"github.com/decred/vspd/internal/vspd"
@@ -45,6 +46,21 @@ func fileExists(name string) bool {
 	return true
 }
 
+// validatePubkey returns an error if the provided key is invalid, not for the
+// expected network, or it is public instead of private.
+func validatePubkey(key string, network *config.Network) error {
+	parsedKey, err := hdkeychain.NewKeyFromString(key, network.Params)
+	if err != nil {
+		return fmt.Errorf("failed to parse feexpub: %w", err)
+	}
+
+	if parsedKey.IsPrivate() {
+		return errors.New("feexpub is a private key, should be public")
+	}
+
+	return nil
+}
+
 func createDatabase(homeDir string, feeXPub string, network *config.Network) error {
 	dataDir := filepath.Join(homeDir, "data", network.Name)
 	dbFile := filepath.Join(dataDir, dbFilename)
@@ -55,14 +71,9 @@ func createDatabase(homeDir string, feeXPub string, network *config.Network) err
 	}
 
 	// Ensure provided xpub is a valid key for the selected network.
-	feeXpub, err := hdkeychain.NewKeyFromString(feeXPub, network.Params)
+	err := validatePubkey(feeXPub, network)
 	if err != nil {
-		return fmt.Errorf("failed to parse feexpub: %w", err)
-	}
-
-	// Ensure key is public.
-	if feeXpub.IsPrivate() {
-		return errors.New("feexpub is a private key, should be public")
+		return err
 	}
 
 	// Ensure the data directory exists.
@@ -106,6 +117,29 @@ func writeConfig(homeDir string) error {
 	return nil
 }
 
+func retireXPub(homeDir string, feeXPub string, network *config.Network) error {
+	dataDir := filepath.Join(homeDir, "data", network.Name)
+	dbFile := filepath.Join(dataDir, dbFilename)
+
+	// Ensure provided xpub is a valid key for the selected network.
+	err := validatePubkey(feeXPub, network)
+	if err != nil {
+		return err
+	}
+
+	db, err := database.Open(dbFile, slog.Disabled, 999)
+	if err != nil {
+		return fmt.Errorf("error opening db file %s: %w", dbFile, err)
+	}
+
+	err = db.RetireXPub(feeXPub)
+	if err != nil {
+		return fmt.Errorf("db.RetireXPub failed: %w", err)
+	}
+
+	return nil
+}
+
 // run is the real main function for vspadmin. It is necessary to work around
 // the fact that deferred functions do not run when os.Exit() is called.
 func run() int {
@@ -161,6 +195,22 @@ func run() int {
 		log("Config file with default values written to %s", cfg.HomeDir)
 		log("Edit the file and fill in values specific to your vspd deployment")
 
+	case "retirexpub":
+		if len(remainingArgs) != 2 {
+			log("retirexpub has one required argument, fee xpub")
+			return 1
+		}
+
+		feeXPub := remainingArgs[1]
+
+		err = retireXPub(cfg.HomeDir, feeXPub, network)
+		if err != nil {
+			log("retirexpub failed: %v", err)
+			return 1
+		}
+
+		log("Xpub successfully retired, all future tickets will use the new xpub")
+
 	default:
 		log("%q is not a valid command", remainingArgs[0])
 		return 1

database/database_test.go

@@ -78,6 +78,7 @@ func TestDatabase(t *testing.T) {
 		"testFilterTickets":     testFilterTickets,
 		"testCountTickets":      testCountTickets,
 		"testFeeXPub":           testFeeXPub,
+		"testRetireFeeXPub":     testRetireFeeXPub,
 		"testDeleteTicket":      testDeleteTicket,
 		"testVoteChangeRecords": testVoteChangeRecords,
 		"testHTTPBackup":        testHTTPBackup,

database/feexpub.go

@@ -6,7 +6,9 @@ package database
 
 import (
 	"encoding/json"
+	"errors"
 	"fmt"
+	"time"
 
 	bolt "go.etcd.io/bbolt"
 )
@@ -63,6 +65,49 @@ func (vdb *VspDatabase) FeeXPub() (FeeXPub, error) {
 	return xpubs[highest], nil
 }
 
+// RetireXPub will mark the currently active xpub key as retired and insert the
+// provided pubkey as the currently active one.
+func (vdb *VspDatabase) RetireXPub(xpub string) error {
+	// Ensure the new xpub has never been used before.
+	xpubs, err := vdb.AllXPubs()
+	if err != nil {
+		return err
+	}
+	for _, x := range xpubs {
+		if x.Key == xpub {
+			return errors.New("provided xpub has already been used")
+		}
+	}
+
+	current, err := vdb.FeeXPub()
+	if err != nil {
+		return err
+	}
+	current.Retired = time.Now().Unix()
+
+	return vdb.db.Update(func(tx *bolt.Tx) error {
+		// Store the retired xpub.
+		err := insertFeeXPub(tx, current)
+		if err != nil {
+			return err
+		}
+
+		// Insert new xpub.
+		newKey := FeeXPub{
+			ID:          current.ID + 1,
+			Key:         xpub,
+			LastUsedIdx: 0,
+			Retired:     0,
+		}
+		err = insertFeeXPub(tx, newKey)
+		if err != nil {
+			return err
+		}
+
+		return nil
+	})
+}
+
 // AllXPubs retrieves the current and any retired extended pubkeys from the
 // database.
 func (vdb *VspDatabase) AllXPubs() (map[uint32]FeeXPub, error) {

database/feexpub_test.go

@@ -57,3 +57,61 @@ func testFeeXPub(t *testing.T) {
 		t.Fatalf("expected xpub retirement 0, got %d", retrievedXPub.Retired)
 	}
 }
+
+func testRetireFeeXPub(t *testing.T) {
+	// Increment the last used index to simulate some usage.
+	idx := uint32(99)
+	err := db.SetLastAddressIndex(idx)
+	if err != nil {
+		t.Fatalf("error setting address index: %v", err)
+	}
+
+	// Ensure a previously used xpub is rejected.
+	err = db.RetireXPub(feeXPub)
+	if err == nil {
+		t.Fatalf("previous xpub was not rejected")
+	}
+
+	const expectedErr = "provided xpub has already been used"
+	if err == nil || err.Error() != expectedErr {
+		t.Fatalf("incorrect error, expected %q, got %q",
+			expectedErr, err.Error())
+	}
+
+	// An unused xpub should be accepted.
+	const feeXPub2 = "feexpub2"
+	err = db.RetireXPub(feeXPub2)
+	if err != nil {
+		t.Fatalf("retiring xpub failed: %v", err)
+	}
+
+	// Retrieve the new xpub. Index should be incremented, last addr should be
+	// reset to 0, key should not be retired.
+	retrievedXPub, err := db.FeeXPub()
+	if err != nil {
+		t.Fatalf("error getting fee xpub: %v", err)
+	}
+
+	if retrievedXPub.Key != feeXPub2 {
+		t.Fatalf("expected fee xpub %q, got %q", feeXPub2, retrievedXPub.Key)
+	}
+	if retrievedXPub.ID != 1 {
+		t.Fatalf("expected xpub ID 1, got %d", retrievedXPub.ID)
+	}
+	if retrievedXPub.LastUsedIdx != 0 {
+		t.Fatalf("expected xpub last used 0, got %d", retrievedXPub.LastUsedIdx)
+	}
+	if retrievedXPub.Retired != 0 {
+		t.Fatalf("expected xpub retirement 0, got %d", retrievedXPub.Retired)
+	}
+
+	// Old xpub should have retired field set.
+	xpubs, err := db.AllXPubs()
+	if err != nil {
+		t.Fatalf("error getting all fee xpubs: %v", err)
+	}
+
+	if xpubs[0].Retired == 0 {
+		t.Fatalf("old xpub retired field not set")
+	}
+}