waddrmgr: add support for wallet birthday for creating new wallet

TODO: support for wallet upgrades and key imports

waddrmgr/db.go

@@ -194,6 +194,7 @@ var (
 	// Sync related key names (sync bucket).
 	syncedToName   = []byte("syncedto")
 	startBlockName = []byte("startblock")
+	birthdayName   = []byte("birthday")
 
 	// Account related key names (account bucket).
 	acctNumAcctsName = []byte("numaccts")
@@ -1489,6 +1490,37 @@ func putStartBlock(ns walletdb.ReadWriteBucket, bs *BlockStamp) error {
 	return nil
 }
 
+// fetchBirthday loads the manager's bithday timestamp from the database.
+func fetchBirthday(ns walletdb.ReadBucket) (time.Time, error) {
+	bucket := ns.NestedReadBucket(syncBucketName)
+
+	var t time.Time
+
+	buf := bucket.Get(birthdayName)
+	if len(buf) != 8 {
+		str := "malformed birthday stored in database"
+		return t, managerError(ErrDatabase, str, nil)
+	}
+
+	t = time.Unix(int64(binary.BigEndian.Uint64(buf)), 0)
+	return t, nil
+}
+
+// putBirthday stores the provided birthday timestamp to the database.
+func putBirthday(ns walletdb.ReadWriteBucket, t time.Time) error {
+	bucket := ns.NestedReadWriteBucket(syncBucketName)
+
+	buf := make([]byte, 8)
+	binary.BigEndian.PutUint64(buf, uint64(t.Unix()))
+
+	err := bucket.Put(birthdayName, buf)
+	if err != nil {
+		str := "failed to store birthday"
+		return managerError(ErrDatabase, str, err)
+	}
+	return nil
+}
+
 // managerExists returns whether or not the manager has already been created
 // in the given database namespace.
 func managerExists(ns walletdb.ReadBucket) bool {

waddrmgr/manager.go

@@ -9,6 +9,7 @@ import (
 	"crypto/sha512"
 	"fmt"
 	"sync"
+	"time"
 
 	"github.com/roasbeef/btcd/btcec"
 	"github.com/roasbeef/btcd/chaincfg"
@@ -249,6 +250,7 @@ type Manager struct {
 	chainParams  *chaincfg.Params
 	addrs        map[addrKey]ManagedAddress
 	syncState    syncState
+	birthday     time.Time
 	watchingOnly bool
 	locked       bool
 	closed       bool
@@ -1985,12 +1987,13 @@ func (m *Manager) Decrypt(keyType CryptoKeyType, in []byte) ([]byte, error) {
 func newManager(chainParams *chaincfg.Params, masterKeyPub *snacl.SecretKey,
 	masterKeyPriv *snacl.SecretKey, cryptoKeyPub EncryptorDecryptor,
 	cryptoKeyPrivEncrypted, cryptoKeyScriptEncrypted []byte, syncInfo *syncState,
-	privPassphraseSalt [saltSize]byte) *Manager {
+	birthday time.Time, privPassphraseSalt [saltSize]byte) *Manager {
 
 	return &Manager{
 		chainParams:              chainParams,
 		addrs:                    make(map[addrKey]ManagedAddress),
 		syncState:                *syncInfo,
+		birthday:                 birthday,
 		locked:                   true,
 		acctInfo:                 make(map[uint32]*accountInfo),
 		masterKeyPub:             masterKeyPub,
@@ -2124,6 +2127,10 @@ func loadManager(ns walletdb.ReadBucket, pubPassphrase []byte, chainParams *chai
 	if err != nil {
 		return nil, maybeConvertDbError(err)
 	}
+	birthday, err := fetchBirthday(ns)
+	if err != nil {
+		return nil, maybeConvertDbError(err)
+	}
 
 	// When not a watching-only manager, set the master private key params,
 	// but don't derive it now since the manager starts off locked.
@@ -2174,7 +2181,7 @@ func loadManager(ns walletdb.ReadBucket, pubPassphrase []byte, chainParams *chai
 	// call to new with the values loaded from the database.
 	mgr := newManager(chainParams, &masterKeyPub, &masterKeyPriv,
 		cryptoKeyPub, cryptoKeyPrivEnc, cryptoKeyScriptEnc, syncInfo,
-		privPassphraseSalt)
+		birthday, privPassphraseSalt)
 	mgr.watchingOnly = watchingOnly
 	return mgr, nil
 }
@@ -2438,6 +2445,11 @@ func Create(ns walletdb.ReadWriteBucket, seed, pubPassphrase, privPassphrase []b
 		if err != nil {
 			return err
 		}
+		// Use 48 hours as margin of safety for wallet birthday.
+		err = putBirthday(ns, time.Now().Add(-48*time.Hour))
+		if err != nil {
+			return err
+		}
 
 		// Save the information for the imported account to the database.
 		err = putAccountInfo(ns, ImportedAddrAccount, nil,

waddrmgr/sync.go

@@ -5,6 +5,8 @@
 package waddrmgr
 
 import (
+	"time"
+
 	"github.com/roasbeef/btcd/chaincfg/chainhash"
 	"github.com/roasbeef/btcwallet/walletdb"
 )
@@ -87,3 +89,23 @@ func (m *Manager) BlockHash(ns walletdb.ReadBucket, height int32) (
 
 	return fetchBlockHash(ns, height)
 }
+
+// Birthday returns the birthday, or earliest time a key could have been used,
+// for the manager.
+func (m *Manager) Birthday() time.Time {
+	m.mtx.Lock()
+	defer m.mtx.Unlock()
+
+	return m.birthday
+}
+
+// SetBirthday sets the birthday, or earliest time a key could have been used,
+// for the manager.
+func (m *Manager) SetBirthday(ns walletdb.ReadWriteBucket,
+	birthday time.Time) error {
+	m.mtx.Lock()
+	defer m.mtx.Unlock()
+
+	m.birthday = birthday
+	return putBirthday(ns, birthday)
+}