Fix isKeyper check

The eon field in messages refers to the keyper set index, not the
keyper-internal eon (which is a counter that includes failed DKG
attempts).

Author: jannikluhn

rolling-shutter/keyper/database/extend.go

@@ -86,3 +86,20 @@ func (q *Queries) ScheduleShutterMessage(
 		Msg("scheduled shuttermint message")
 	return nil
 }
+
+// GetKeyperIndex returns the index of the keyper with the given address in the keyper set with
+// the given index. If the keyper is not found, the second return value is false.
+func (q *Queries) GetKeyperIndex(ctx context.Context, keyperConfigIndex int64, addr common.Address) (int64, bool, error) {
+	batchConfig, err := q.GetBatchConfig(ctx, int32(keyperConfigIndex))
+	if err != nil {
+		return -1, false, errors.Wrapf(err, "failed to get config %d from db", keyperConfigIndex)
+	}
+
+	encodedAddress := shdb.EncodeAddress(addr)
+	for i, address := range batchConfig.Keypers {
+		if address == encodedAddress {
+			return int64(i), true, nil
+		}
+	}
+	return -1, false, nil
+}

rolling-shutter/keyper/epochkghandler/key.go

@@ -46,15 +46,9 @@ func (handler *DecryptionKeyHandler) ValidateMessage(ctx context.Context, msg p2
 
 	queries := database.New(handler.dbpool)
 
-	isKeyper, err := queries.GetKeyperStateForEon(ctx, database.GetKeyperStateForEonParams{
-		KeyperAddress: []string{handler.config.GetAddress().String()},
-		Eon:           int64(key.Eon),
-	})
-	if errors.Is(err, pgx.ErrNoRows) {
-		return pubsub.ValidationReject, errors.Errorf("eon %d does not exist", key.Eon)
-	}
+	_, isKeyper, err := queries.GetKeyperIndex(ctx, int64(key.Eon), handler.config.GetAddress())
 	if err != nil {
-		return pubsub.ValidationReject, errors.Errorf("failed to get keyper state for eon %d from db", key.Eon)
+		return pubsub.ValidationReject, err
 	}
 	if !isKeyper {
 		log.Debug().Uint64("eon", key.Eon).Msg("Ignoring decryptionKey for eon; we're not a Keyper")

rolling-shutter/keyper/epochkghandler/keyshare.go

@@ -47,19 +47,12 @@ func (handler *DecryptionKeyShareHandler) ValidateMessage(ctx context.Context, m
 	}
 
 	queries := database.New(handler.dbpool)
-
-	isKeyper, err := queries.GetKeyperStateForEon(ctx, database.GetKeyperStateForEonParams{
-		KeyperAddress: []string{handler.config.GetAddress().String()},
-		Eon:           int64(keyShare.Eon),
-	})
-	if errors.Is(err, pgx.ErrNoRows) {
-		return pubsub.ValidationReject, errors.Errorf("eon %d does not exist", keyShare.Eon)
-	}
+	_, isKeyper, err := queries.GetKeyperIndex(ctx, int64(keyShare.Eon), handler.config.GetAddress())
 	if err != nil {
-		return pubsub.ValidationReject, errors.Errorf("failed to get keyper state for eon %d from db", keyShare.Eon)
+		return pubsub.ValidationReject, err
 	}
 	if !isKeyper {
-		log.Debug().Uint64("eon", keyShare.Eon).Msg("ignoring KeyShare for eon; we're not a Keyper")
+		log.Debug().Uint64("eon", keyShare.Eon).Msg("Ignoring decryptionKey for eon; we're not a Keyper")
 		return pubsub.ValidationReject, nil
 	}
 

rolling-shutter/keyper/epochkghandler/sendkeyshare.go

@@ -57,22 +57,13 @@ func (ksh *KeyShareHandler) ConstructDecryptionKeyShares(
 	if len(identityPreimages) > MaxNumKeysPerMessage {
 		return nil, errors.Errorf("too many decryption key shares for message (%d > %d)", len(identityPreimages), MaxNumKeysPerMessage)
 	}
+
 	db := database.New(ksh.DBPool)
-	batchConfig, err := db.GetBatchConfig(ctx, int32(eon.KeyperConfigIndex))
+	keyperIndex, isKeyper, err := db.GetKeyperIndex(ctx, eon.KeyperConfigIndex, ksh.KeyperAddress)
 	if err != nil {
-		return nil, errors.Wrapf(err, "failed to get config %d from db", eon.KeyperConfigIndex)
-	}
-
-	// get our keyper index (and check that we in fact are a keyper)
-	encodedAddress := shdb.EncodeAddress(ksh.KeyperAddress)
-	keyperIndex := int64(-1)
-	for i, address := range batchConfig.Keypers {
-		if address == encodedAddress {
-			keyperIndex = int64(i)
-			break
-		}
+		return nil, err
 	}
-	if keyperIndex == -1 {
+	if !isKeyper {
 		return nil, errors.Wrap(ErrNotAKeyper, ErrIgnoreDecryptionRequest.Error())
 	}