Restrict ClearPrefix by key size (ava-labs#265)

core/rawdb/accessors_state_sync.go

@@ -86,13 +86,12 @@ func ClearSyncSegments(db ethdb.KeyValueStore, root common.Hash) error {
 	segmentsPrefix := make([]byte, len(syncSegmentsPrefix)+common.HashLength)
 	copy(segmentsPrefix, syncSegmentsPrefix)
 	copy(segmentsPrefix[len(syncSegmentsPrefix):], root[:])
-
-	return ClearPrefix(db, segmentsPrefix)
+	return ClearPrefix(db, segmentsPrefix, syncSegmentsKeyLength)
 }
 
 // ClearAllSyncSegments removes all segment markers from db
 func ClearAllSyncSegments(db ethdb.KeyValueStore) error {
-	return ClearPrefix(db, syncSegmentsPrefix)
+	return ClearPrefix(db, syncSegmentsPrefix, syncSegmentsKeyLength)
 }
 
 // UnpackSyncSegmentKey returns the root and start position for a trie segment
@@ -131,12 +130,12 @@ func ClearSyncStorageTrie(db ethdb.KeyValueStore, root common.Hash) error {
 	accountsPrefix := make([]byte, len(syncStorageTriesPrefix)+common.HashLength)
 	copy(accountsPrefix, syncStorageTriesPrefix)
 	copy(accountsPrefix[len(syncStorageTriesPrefix):], root[:])
-	return ClearPrefix(db, accountsPrefix)
+	return ClearPrefix(db, accountsPrefix, syncStorageTriesKeyLength)
 }
 
 // ClearAllSyncStorageTries removes all storage tries added for syncing from db
 func ClearAllSyncStorageTries(db ethdb.KeyValueStore) error {
-	return ClearPrefix(db, syncStorageTriesPrefix)
+	return ClearPrefix(db, syncStorageTriesPrefix, syncStorageTriesKeyLength)
 }
 
 // UnpackSyncStorageTrieKey returns the root and account for a storage trie

core/rawdb/accessors_state_sync_test.go

@@ -0,0 +1,33 @@
+// (c) 2023, Ava Labs, Inc. All rights reserved.
+// See the file LICENSE for licensing terms.
+
+package rawdb
+
+import (
+	"testing"
+
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/stretchr/testify/require"
+)
+
+func TestClearPrefix(t *testing.T) {
+	require := require.New(t)
+	db := NewMemoryDatabase()
+	// add a key that should be cleared
+	require.NoError(WriteSyncSegment(db, common.Hash{1}, common.Hash{}.Bytes()))
+
+	// add a key that should not be cleared
+	key := append(syncSegmentsPrefix, []byte("foo")...)
+	require.NoError(db.Put(key, []byte("bar")))
+
+	require.NoError(ClearAllSyncSegments(db))
+
+	count := 0
+	it := db.NewIterator(syncSegmentsPrefix, nil)
+	defer it.Release()
+	for it.Next() {
+		count++
+	}
+	require.NoError(it.Error())
+	require.Equal(1, count)
+}

core/rawdb/database.go

@@ -324,14 +324,19 @@ func InspectDatabase(db ethdb.Database, keyPrefix, keyStart []byte) error {
 	return nil
 }
 
-// ClearPrefix removes all keys in db that begin with prefix
-func ClearPrefix(db ethdb.KeyValueStore, prefix []byte) error {
+// ClearPrefix removes all keys in db that begin with prefix and match an
+// expected key length. [keyLen] should include the length of the prefix.
+func ClearPrefix(db ethdb.KeyValueStore, prefix []byte, keyLen int) error {
 	it := db.NewIterator(prefix, nil)
 	defer it.Release()
 
 	batch := db.NewBatch()
 	for it.Next() {
 		key := common.CopyBytes(it.Key())
+		if len(key) != keyLen {
+			// avoid deleting keys that do not match the expected length
+			continue
+		}
 		if err := batch.Delete(key); err != nil {
 			return err
 		}