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macaroons: add ability to change the password or create a new root key

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This commit is contained in:
Oliver Gugger 2020-10-06 17:23:30 +02:00
parent cd85e17b19
commit ae71d60715
No known key found for this signature in database
GPG Key ID: 8E4256593F177720
3 changed files with 290 additions and 49 deletions
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16
macaroons/service.go
View File

@ -257,8 +257,8 @@ func (svc *Service) ValidateMacaroon(ctx context.Context,
return err
}
// Check the method being called against the permitted operation and
// the expiration time and IP address and return the result.
// Check the method being called against the permitted operation, the
// expiration time and IP address and return the result.
authChecker := svc.Checker.Auth(macaroon.Slice{mac})
_, err = authChecker.Allow(ctx, requiredPermissions...)
@ -325,3 +325,15 @@ func (svc *Service) DeleteMacaroonID(ctxt context.Context,
rootKeyID []byte) ([]byte, error) {
return svc.rks.DeleteMacaroonID(ctxt, rootKeyID)
}
// GenerateNewRootKey calls the underlying root key store's GenerateNewRootKey
// and returns the result.
func (svc *Service) GenerateNewRootKey() error {
return svc.rks.GenerateNewRootKey()
}
// ChangePassword calls the underlying root key store's ChangePassword and
// returns the result.
func (svc *Service) ChangePassword(oldPw, newPw []byte) error {
return svc.rks.ChangePassword(oldPw, newPw)
}

171
macaroons/store.go
View File

@ -11,6 +11,7 @@ import (
"github.com/lightningnetwork/lnd/channeldb/kvdb"
"github.com/btcsuite/btcwallet/snacl"
"github.com/btcsuite/btcwallet/walletdb"
)
const (
@ -26,10 +27,10 @@ var (
// just 0, to emulate the memory storage that comes with bakery.
DefaultRootKeyID = []byte("0")
// encryptedKeyID is the name of the database key that stores the
// encryptionKeyID is the name of the database key that stores the
// encryption key, encrypted with a salted + hashed password. The
// format is 32 bytes of salt, and the rest is encrypted key.
encryptedKeyID = []byte("enckey")
encryptionKeyID = []byte("enckey")
// ErrAlreadyUnlocked specifies that the store has already been
// unlocked.
@ -45,6 +46,15 @@ var (
// ErrKeyValueForbidden is used when the root key ID uses encryptedKeyID as
// its value.
ErrKeyValueForbidden = fmt.Errorf("root key ID value is not allowed")
// ErrRootKeyBucketNotFound specifies that there is no macaroon root key
// bucket yet which can/should only happen if the store has been
// corrupted or was initialized incorrectly.
ErrRootKeyBucketNotFound = fmt.Errorf("root key bucket not found")
// ErrEncKeyNotFound specifies that there was no encryption key found
// even if one was expected to be generated.
ErrEncKeyNotFound = fmt.Errorf("macaroon encryption key not found")
)
// RootKeyStorage implements the bakery.RootKeyStorage interface.
@ -89,7 +99,10 @@ func (r *RootKeyStorage) CreateUnlock(password *[]byte) error {
return kvdb.Update(r, func(tx kvdb.RwTx) error {
bucket := tx.ReadWriteBucket(rootKeyBucketName)
dbKey := bucket.Get(encryptedKeyID)
if bucket == nil {
return ErrRootKeyBucketNotFound
}
dbKey := bucket.Get(encryptionKeyID)
if len(dbKey) > 0 {
// We've already stored a key, so try to unlock with
// the password.
@ -116,7 +129,7 @@ func (r *RootKeyStorage) CreateUnlock(password *[]byte) error {
return err
}
err = bucket.Put(encryptedKeyID, encKey.Marshal())
err = bucket.Put(encryptionKeyID, encKey.Marshal())
if err != nil {
return err
}
@ -126,6 +139,83 @@ func (r *RootKeyStorage) CreateUnlock(password *[]byte) error {
}, func() {})
}
// ChangePassword decrypts the macaroon root key with the old password and then
// encrypts it again with the new password.
func (r *RootKeyStorage) ChangePassword(oldPw, newPw []byte) error {
// We need the store to already be unlocked. With this we can make sure
// that there already is a key in the DB.
if r.encKey == nil {
return ErrStoreLocked
}
// Check if a nil password has been passed; return an error if so.
if oldPw == nil || newPw == nil {
return ErrPasswordRequired
}
return kvdb.Update(r, func(tx kvdb.RwTx) error {
bucket := tx.ReadWriteBucket(rootKeyBucketName)
if bucket == nil {
return ErrRootKeyBucketNotFound
}
encKeyDb := bucket.Get(encryptionKeyID)
rootKeyDb := bucket.Get(DefaultRootKeyID)
// Both the encryption key and the root key must be present
// otherwise we are in the wrong state to change the password.
if len(encKeyDb) == 0 || len(rootKeyDb) == 0 {
return ErrEncKeyNotFound
}
// Unmarshal parameters for old encryption key and derive the
// old key with them.
encKeyOld := &snacl.SecretKey{}
err := encKeyOld.Unmarshal(encKeyDb)
if err != nil {
return err
}
err = encKeyOld.DeriveKey(&oldPw)
if err != nil {
return err
}
// Create a new encryption key from the new password.
encKeyNew, err := snacl.NewSecretKey(
&newPw, scryptN, scryptR, scryptP,
)
if err != nil {
return err
}
// Now try to decrypt the root key with the old encryption key,
// encrypt it with the new one and then store it in the DB.
decryptedKey, err := encKeyOld.Decrypt(rootKeyDb)
if err != nil {
return err
}
rootKey := make([]byte, len(decryptedKey))
copy(rootKey, decryptedKey)
encryptedKey, err := encKeyNew.Encrypt(rootKey)
if err != nil {
return err
}
err = bucket.Put(DefaultRootKeyID, encryptedKey)
if err != nil {
return err
}
// Finally, store the new encryption key parameters in the DB
// as well.
err = bucket.Put(encryptionKeyID, encKeyNew.Marshal())
if err != nil {
return err
}
r.encKey = encKeyNew
return nil
}, func() {})
}
// Get implements the Get method for the bakery.RootKeyStorage interface.
func (r *RootKeyStorage) Get(_ context.Context, id []byte) ([]byte, error) {
r.encKeyMtx.RLock()
@ -136,7 +226,11 @@ func (r *RootKeyStorage) Get(_ context.Context, id []byte) ([]byte, error) {
}
var rootKey []byte
err := kvdb.View(r, func(tx kvdb.RTx) error {
dbKey := tx.ReadBucket(rootKeyBucketName).Get(id)
bucket := tx.ReadBucket(rootKeyBucketName)
if bucket == nil {
return ErrRootKeyBucketNotFound
}
dbKey := bucket.Get(id)
if len(dbKey) == 0 {
return fmt.Errorf("root key with id %s doesn't exist",
string(id))
@ -178,13 +272,16 @@ func (r *RootKeyStorage) RootKey(ctx context.Context) ([]byte, []byte, error) {
return nil, nil, err
}
if bytes.Equal(id, encryptedKeyID) {
if bytes.Equal(id, encryptionKeyID) {
return nil, nil, ErrKeyValueForbidden
}
err = kvdb.Update(r, func(tx kvdb.RwTx) error {
ns := tx.ReadWriteBucket(rootKeyBucketName)
dbKey := ns.Get(id)
bucket := tx.ReadWriteBucket(rootKeyBucketName)
if bucket == nil {
return ErrRootKeyBucketNotFound
}
dbKey := bucket.Get(id)
// If there's a root key stored in the bucket, decrypt it and
// return it.
@ -199,18 +296,11 @@ func (r *RootKeyStorage) RootKey(ctx context.Context) ([]byte, []byte, error) {
return nil
}
// Otherwise, create a RootKeyLen-byte root key, encrypt it,
// Otherwise, create a new root key, encrypt it,
// and store it in the bucket.
rootKey = make([]byte, RootKeyLen)
if _, err := io.ReadFull(rand.Reader, rootKey[:]); err != nil {
return err
}
encKey, err := r.encKey.Encrypt(rootKey)
if err != nil {
return err
}
return ns.Put(id, encKey)
newKey, err := generateAndStoreNewRootKey(bucket, id, r.encKey)
rootKey = newKey
return err
}, func() {
rootKey = nil
})
@ -221,6 +311,26 @@ func (r *RootKeyStorage) RootKey(ctx context.Context) ([]byte, []byte, error) {
return rootKey, id, nil
}
// GenerateNewRootKey generates a new macaroon root key, replacing the previous
// root key if it existed.
func (r *RootKeyStorage) GenerateNewRootKey() error {
// We need the store to already be unlocked. With this we can make sure
// that there already is a key in the DB that can be replaced.
if r.encKey == nil {
return ErrStoreLocked
}
return kvdb.Update(r, func(tx kvdb.RwTx) error {
bucket := tx.ReadWriteBucket(rootKeyBucketName)
if bucket == nil {
return ErrRootKeyBucketNotFound
}
_, err := generateAndStoreNewRootKey(
bucket, DefaultRootKeyID, r.encKey,
)
return err
}, func() {})
}
// Close closes the underlying database and zeroes the encryption key stored
// in memory.
func (r *RootKeyStorage) Close() error {
@ -229,10 +339,29 @@ func (r *RootKeyStorage) Close() error {
if r.encKey != nil {
r.encKey.Zero()
r.encKey = nil
}
return r.Backend.Close()
}
// generateAndStoreNewRootKey creates a new random RootKeyLen-byte root key,
// encrypts it with the given encryption key and stores it in the bucket.
// Any previously set key will be overwritten.
func generateAndStoreNewRootKey(bucket walletdb.ReadWriteBucket, id []byte,
key *snacl.SecretKey) ([]byte, error) {
rootKey := make([]byte, RootKeyLen)
if _, err := io.ReadFull(rand.Reader, rootKey); err != nil {
return nil, err
}
encryptedKey, err := key.Encrypt(rootKey)
if err != nil {
return nil, err
}
return rootKey, bucket.Put(id, encryptedKey)
}
// ListMacaroonIDs returns all the root key ID values except the value of
// encryptedKeyID.
func (r *RootKeyStorage) ListMacaroonIDs(_ context.Context) ([][]byte, error) {
@ -254,7 +383,7 @@ func (r *RootKeyStorage) ListMacaroonIDs(_ context.Context) ([][]byte, error) {
// to rootKeySlice.
appendRootKey := func(k, _ []byte) error {
// Only append when the key value is not encryptedKeyID.
if !bytes.Equal(k, encryptedKeyID) {
if !bytes.Equal(k, encryptionKeyID) {
rootKeySlice = append(rootKeySlice, k)
}
return nil
@ -290,7 +419,7 @@ func (r *RootKeyStorage) DeleteMacaroonID(
}
// Deleting encryptedKeyID or DefaultRootKeyID is not allowed.
if bytes.Equal(rootKeyID, encryptedKeyID) ||
if bytes.Equal(rootKeyID, encryptionKeyID) ||
bytes.Equal(rootKeyID, DefaultRootKeyID) {
return nil, ErrDeletionForbidden

152
macaroons/store_test.go
View File

@ -14,12 +14,31 @@ import (
"github.com/stretchr/testify/require"
)
func TestStore(t *testing.T) {
var (
defaultRootKeyIDContext = macaroons.ContextWithRootKeyID(
context.Background(), macaroons.DefaultRootKeyID,
)
)
// newTestStore creates a new bolt DB in a temporary directory and then
// initializes a root key storage for that DB.
func newTestStore(t *testing.T) (string, func(), *macaroons.RootKeyStorage) {
tempDir, err := ioutil.TempDir("", "macaroonstore-")
require.NoError(t, err)
defer func() {
cleanup, store := openTestStore(t, tempDir)
cleanup2 := func() {
cleanup()
_ = os.RemoveAll(tempDir)
}()
}
return tempDir, cleanup2, store
}
// openTestStore opens an existing bolt DB and then initializes a root key
// storage for that DB.
func openTestStore(t *testing.T, tempDir string) (func(),
*macaroons.RootKeyStorage) {
db, err := kvdb.Create(
kvdb.BoltBackendName, path.Join(tempDir, "weks.db"), true,
@ -31,11 +50,21 @@ func TestStore(t *testing.T) {
_ = db.Close()
t.Fatalf("Error creating root key store: %v", err)
}
defer func() {
_ = store.Close()
}()
_, _, err = store.RootKey(context.TODO())
cleanup := func() {
_ = store.Close()
}
return cleanup, store
}
// TestStore tests the normal use cases of the store like creating, unlocking,
// reading keys and closing it.
func TestStore(t *testing.T) {
tempDir, cleanup, store := newTestStore(t)
defer cleanup()
_, _, err := store.RootKey(context.TODO())
require.Equal(t, macaroons.ErrStoreLocked, err)
_, err = store.Get(context.TODO(), nil)
@ -63,16 +92,13 @@ func TestStore(t *testing.T) {
require.Equal(t, macaroons.ErrKeyValueForbidden, err)
// Create a context with root key ID value.
ctx := macaroons.ContextWithRootKeyID(
context.TODO(), macaroons.DefaultRootKeyID,
)
key, id, err := store.RootKey(ctx)
key, id, err := store.RootKey(defaultRootKeyIDContext)
require.NoError(t, err)
rootID := id
require.Equal(t, macaroons.DefaultRootKeyID, rootID)
key2, err := store.Get(ctx, id)
key2, err := store.Get(defaultRootKeyIDContext, id)
require.NoError(t, err)
require.Equal(t, key, key2)
@ -85,16 +111,7 @@ func TestStore(t *testing.T) {
// Between here and the re-opening of the store, it's possible to get
// a double-close, but that's not such a big deal since the tests will
// fail anyway in that case.
db, err = kvdb.Create(
kvdb.BoltBackendName, path.Join(tempDir, "weks.db"), true,
)
require.NoError(t, err)
store, err = macaroons.NewRootKeyStorage(db)
if err != nil {
_ = db.Close()
t.Fatalf("Error creating root key store: %v", err)
}
_, store = openTestStore(t, tempDir)
err = store.CreateUnlock(&badpw)
require.Equal(t, snacl.ErrInvalidPassword, err)
@ -102,21 +119,104 @@ func TestStore(t *testing.T) {
err = store.CreateUnlock(nil)
require.Equal(t, macaroons.ErrPasswordRequired, err)
_, _, err = store.RootKey(ctx)
_, _, err = store.RootKey(defaultRootKeyIDContext)
require.Equal(t, macaroons.ErrStoreLocked, err)
_, err = store.Get(ctx, nil)
_, err = store.Get(defaultRootKeyIDContext, nil)
require.Equal(t, macaroons.ErrStoreLocked, err)
err = store.CreateUnlock(&pw)
require.NoError(t, err)
key, err = store.Get(ctx, rootID)
key, err = store.Get(defaultRootKeyIDContext, rootID)
require.NoError(t, err)
require.Equal(t, key, key2)
key, id, err = store.RootKey(ctx)
key, id, err = store.RootKey(defaultRootKeyIDContext)
require.NoError(t, err)
require.Equal(t, key, key2)
require.Equal(t, rootID, id)
}
// TestStoreGenerateNewRootKey tests that a root key can be replaced with a new
// one in the store without changing the password.
func TestStoreGenerateNewRootKey(t *testing.T) {
_, cleanup, store := newTestStore(t)
defer cleanup()
// The store must be unlocked to replace the root key.
err := store.GenerateNewRootKey()
require.Equal(t, macaroons.ErrStoreLocked, err)
// Unlock the store and read the current key.
pw := []byte("weks")
err = store.CreateUnlock(&pw)
require.NoError(t, err)
oldRootKey, _, err := store.RootKey(defaultRootKeyIDContext)
require.NoError(t, err)
// Replace the root key with a new random key.
err = store.GenerateNewRootKey()
require.NoError(t, err)
// Finally, read the root key from the DB and compare it to the one
// we got returned earlier. This makes sure that the encryption/
// decryption of the key in the DB worked as expected too.
newRootKey, _, err := store.RootKey(defaultRootKeyIDContext)
require.NoError(t, err)
require.NotEqual(t, oldRootKey, newRootKey)
}
// TestStoreChangePassword tests that the password for the store can be changed
// without changing the root key.
func TestStoreChangePassword(t *testing.T) {
tempDir, cleanup, store := newTestStore(t)
defer cleanup()
// The store must be unlocked to replace the root key.
err := store.ChangePassword(nil, nil)
require.Equal(t, macaroons.ErrStoreLocked, err)
// Unlock the DB and read the current root key. This will need to stay
// the same after changing the password for the test to succeed.
pw := []byte("weks")
err = store.CreateUnlock(&pw)
require.NoError(t, err)
rootKey, _, err := store.RootKey(defaultRootKeyIDContext)
require.NoError(t, err)
// Both passwords must be set.
err = store.ChangePassword(nil, nil)
require.Equal(t, macaroons.ErrPasswordRequired, err)
// Make sure that an error is returned if we try to change the password
// without the correct old password.
wrongPw := []byte("wrong")
newPw := []byte("newpassword")
err = store.ChangePassword(wrongPw, newPw)
require.Equal(t, snacl.ErrInvalidPassword, err)
// Now really do change the password.
err = store.ChangePassword(pw, newPw)
require.NoError(t, err)
// Close the store. This will close the underlying DB and we need to
// create a new store instance. Let's make sure we can't use it again
// after closing.
err = store.Close()
require.NoError(t, err)
err = store.CreateUnlock(&newPw)
require.Error(t, err)
// Let's open it again and try unlocking with the new password.
_, store = openTestStore(t, tempDir)
err = store.CreateUnlock(&newPw)
require.NoError(t, err)
// Finally read the root key from the DB using the new password and
// make sure the root key stayed the same.
rootKeyDb, _, err := store.RootKey(defaultRootKeyIDContext)
require.NoError(t, err)
require.Equal(t, rootKey, rootKeyDb)
}