test leveldb panics on mailserver (#1065)

* test leveldb panics on mailserver

* refactoring

* rename DB interface to dbImpl and add documentation

mailserver/cleaner.go

@@ -11,12 +11,12 @@ const batchSize = 1000
 
 // Cleaner removes old messages from a db
 type Cleaner struct {
-	db        *leveldb.DB
+	db        dbImpl
 	batchSize int
 }
 
 // NewCleanerWithDB returns a new Cleaner for db
-func NewCleanerWithDB(db *leveldb.DB) *Cleaner {
+func NewCleanerWithDB(db dbImpl) *Cleaner {
 	return &Cleaner{
 		db:        db,
 		batchSize: batchSize,

mailserver/cleaner_test.go

@@ -95,7 +95,7 @@ func testMessagesCount(t *testing.T, expected int, s *WMailServer) {
 	require.Equal(t, expected, count, fmt.Sprintf("expected %d message, got: %d", expected, count))
 }
 
-func countMessages(t *testing.T, db *leveldb.DB) int {
+func countMessages(t *testing.T, db dbImpl) int {
 	var (
 		count int
 		zero  common.Hash

mailserver/mailserver.go

@@ -31,6 +31,8 @@ import (
 	whisper "github.com/ethereum/go-ethereum/whisper/whisperv6"
 	"github.com/status-im/status-go/params"
 	"github.com/syndtr/goleveldb/leveldb"
+	"github.com/syndtr/goleveldb/leveldb/iterator"
+	"github.com/syndtr/goleveldb/leveldb/opt"
 	"github.com/syndtr/goleveldb/leveldb/util"
 )
 
@@ -53,9 +55,23 @@ var (
 	archivedErrorsCounter  = metrics.NewRegisteredCounter("mailserver/archiveErrors", nil)
 )
 
+// dbImpl is an interface introduced to be able to test some unexpected
+// panics from leveldb that are difficult to reproduce.
+// normally the db implementation is leveldb.DB, but in TestMailServerDBPanicSuite
+// we use panicDB to test panics from the db.
+// more info about the panic errors:
+// https://github.com/syndtr/goleveldb/issues/224
+type dbImpl interface {
+	Close() error
+	Write(*leveldb.Batch, *opt.WriteOptions) error
+	Put([]byte, []byte, *opt.WriteOptions) error
+	Get([]byte, *opt.ReadOptions) ([]byte, error)
+	NewIterator(*util.Range, *opt.ReadOptions) iterator.Iterator
+}
+
 // WMailServer whisper mailserver.
 type WMailServer struct {
-	db    *leveldb.DB
+	db    dbImpl
 	w     *whisper.Whisper
 	pow   float64
 	key   []byte
@@ -94,11 +110,12 @@ func (s *WMailServer) Init(shh *whisper.Whisper, config *params.WhisperConfig) e
 		return errPasswordNotProvided
 	}
 
-	s.db, err = leveldb.OpenFile(config.DataDir, nil)
+	db, err := leveldb.OpenFile(config.DataDir, nil)
 	if err != nil {
 		return fmt.Errorf("open DB: %s", err)
 	}
 
+	s.db = db
 	s.w = shh
 	s.pow = config.MinimumPoW
 
@@ -202,7 +219,12 @@ func (s *WMailServer) DeliverMail(peer *whisper.Peer, request *whisper.Envelope)
 	defer recoverLevelDBPanics("DeliverMail")
 
 	if ok, lower, upper, bloom := s.validateRequest(peer.ID(), request); ok {
-		s.processRequest(peer, lower, upper, bloom)
+		_, err := s.processRequest(peer, lower, upper, bloom)
+		if err != nil {
+			log.Error(fmt.Sprintf("error in DeliverMail: %s", err))
+			return
+		}
+
 		if err := s.sendHistoricMessageResponse(peer, request); err != nil {
 			log.Error(fmt.Sprintf("SendHistoricMessageResponse error: %s", err))
 		}
@@ -225,9 +247,14 @@ func (s *WMailServer) exceedsPeerRequests(peer []byte) bool {
 
 // processRequest processes the current request and re-sends all stored messages
 // accomplishing lower and upper limits.
-func (s *WMailServer) processRequest(peer *whisper.Peer, lower, upper uint32, bloom []byte) []*whisper.Envelope {
-	ret := make([]*whisper.Envelope, 0)
-	var err error
+func (s *WMailServer) processRequest(peer *whisper.Peer, lower, upper uint32, bloom []byte) (ret []*whisper.Envelope, err error) {
+	// Recover from possible goleveldb panics
+	defer func() {
+		if r := recover(); r != nil {
+			err = fmt.Errorf("recovered from panic in processRequest: %v", r)
+		}
+	}()
+
 	var zero common.Hash
 	kl := NewDbKey(lower, zero)
 	ku := NewDbKey(upper+1, zero) // LevelDB is exclusive, while the Whisper API is inclusive
@@ -243,9 +270,10 @@ func (s *WMailServer) processRequest(peer *whisper.Peer, lower, upper uint32, bl
 
 	for i.Next() {
 		var envelope whisper.Envelope
-		err = rlp.DecodeBytes(i.Value(), &envelope)
-		if err != nil {
-			log.Error(fmt.Sprintf("RLP decoding failed: %s", err))
+		decodeErr := rlp.DecodeBytes(i.Value(), &envelope)
+		if decodeErr != nil {
+			log.Error(fmt.Sprintf("RLP decoding failed: %s", decodeErr))
+			continue
 		}
 
 		if whisper.BloomFilterMatch(bloom, envelope.Bloom()) {
@@ -256,7 +284,7 @@ func (s *WMailServer) processRequest(peer *whisper.Peer, lower, upper uint32, bl
 				err = s.w.SendP2PDirect(peer, &envelope)
 				if err != nil {
 					log.Error(fmt.Sprintf("Failed to send direct message to peer: %s", err))
-					return nil
+					return
 				}
 			}
 			sentEnvelopes++
@@ -273,7 +301,7 @@ func (s *WMailServer) processRequest(peer *whisper.Peer, lower, upper uint32, bl
 		log.Error(fmt.Sprintf("Level DB iterator error: %s", err))
 	}
 
-	return ret
+	return
 }
 
 func (s *WMailServer) sendHistoricMessageResponse(peer *whisper.Peer, request *whisper.Envelope) error {

mailserver/mailserver_db_panic_test.go

@@ -0,0 +1,66 @@
+package mailserver
+
+import (
+	"testing"
+
+	whisper "github.com/ethereum/go-ethereum/whisper/whisperv6"
+	"github.com/stretchr/testify/suite"
+	"github.com/syndtr/goleveldb/leveldb"
+	"github.com/syndtr/goleveldb/leveldb/iterator"
+	"github.com/syndtr/goleveldb/leveldb/opt"
+	"github.com/syndtr/goleveldb/leveldb/util"
+)
+
+type panicDB struct{}
+
+func (db *panicDB) Close() error {
+	panic("panicDB panic on Close")
+}
+
+func (db *panicDB) Write(b *leveldb.Batch, opts *opt.WriteOptions) error {
+	panic("panicDB panic on Write")
+}
+
+func (db *panicDB) Put(k []byte, v []byte, opts *opt.WriteOptions) error {
+	panic("panicDB panic on Put")
+}
+
+func (db *panicDB) Get(k []byte, opts *opt.ReadOptions) ([]byte, error) {
+	panic("panicDB panic on Get")
+}
+
+func (db *panicDB) NewIterator(r *util.Range, opts *opt.ReadOptions) iterator.Iterator {
+	panic("panicDB panic on NewIterator")
+}
+
+func TestMailServerDBPanicSuite(t *testing.T) {
+	suite.Run(t, new(MailServerDBPanicSuite))
+}
+
+type MailServerDBPanicSuite struct {
+	suite.Suite
+	server *WMailServer
+}
+
+func (s *MailServerDBPanicSuite) SetupTest() {
+	s.server = &WMailServer{}
+	s.server.db = &panicDB{}
+}
+
+func (s *MailServerDBPanicSuite) TestArchive() {
+	defer s.testPanicRecover("Archive")
+	s.server.Archive(&whisper.Envelope{})
+}
+
+func (s *MailServerDBPanicSuite) TestDeliverMail() {
+	defer s.testPanicRecover("DeliverMail")
+	_, err := s.server.processRequest(nil, 10, 20, []byte{})
+	s.Error(err)
+	s.Equal("recovered from panic in processRequest: panicDB panic on NewIterator", err.Error())
+}
+
+func (s *MailServerDBPanicSuite) testPanicRecover(method string) {
+	if r := recover(); r != nil {
+		s.Failf("error recovering panic", "expected recover to return nil, got: %+v", r)
+	}
+}

mailserver/mailserver_test.go

@@ -251,7 +251,8 @@ func (s *MailserverSuite) TestMailServer() {
 
 func (s *MailserverSuite) messageExists(envelope *whisper.Envelope, low, upp uint32, bloom []byte) bool {
 	var exist bool
-	mail := s.server.processRequest(nil, low, upp, bloom)
+	mail, err := s.server.processRequest(nil, low, upp, bloom)
+	s.NoError(err)
 	for _, msg := range mail {
 		if msg.Hash() == envelope.Hash() {
 			exist = true