Fix uint underflow during Keyper set activation

Before activating a new Keyper Set we wait until at least `DKGStartBlockDelta`
blocks before the `activationBlockNumber`.

Since all numbers involved are uints the condition could run into an underflow
when the current block number is already higher than the `activationBlockNumber`.

Author: ulope

rolling-shutter/keyper/keyper.go

@@ -261,7 +261,9 @@ func (kpr *keyper) handleOnChainKeyperSetChanges(
 	if err != nil {
 		return err
 	}
-	if activationBlockNumber-l1BlockNumber > kpr.config.Shuttermint.DKGStartBlockDelta {
+	// We *MUST* check if the l1BlockNumber is smaller than the activationBlockNumber since both are uint64 and therefore subtraction can never result in negative numbers.
+	// This means that if we missed the activationBlockNumber we will never submit the config.
+	if l1BlockNumber < activationBlockNumber && activationBlockNumber-l1BlockNumber > kpr.config.Shuttermint.DKGStartBlockDelta {
 		log.Info().Interface("keyper-set", keyperSet).
 			Uint64("l1-block-number", l1BlockNumber).
 			Uint64("dkg-start-delta", kpr.config.Shuttermint.DKGStartBlockDelta).

rolling-shutter/medley/metricsserver/config.go

@@ -33,12 +33,13 @@ func (mc *MetricsConfig) Validate() error {
 
 func (mc *MetricsConfig) SetDefaultValues() error {
 	mc.Enabled = false
-	mc.Host = "[::]"
-	mc.Port = 9191
 	return nil
 }
 
 func (mc *MetricsConfig) SetExampleValues() error {
+	mc.Enabled = false
+	mc.Host = "[::]"
+	mc.Port = 9100
 	return nil
 }
 

rolling-shutter/snapshotkeyper/snapshotkeyper.go

@@ -228,7 +228,9 @@ func (snkpr *snapshotkeyper) handleOnChainKeyperSetChanges(ctx context.Context,
 	if err != nil {
 		return err
 	}
-	if activationBlockNumber-l1BlockNumber > snkpr.config.Shuttermint.DKGStartBlockDelta {
+	// We *MUST* check if the l1BlockNumber is smaller than the activationBlockNumber since both are uint64 and therefore subtraction can never result in negative numbers.
+	// This means that if we missed the activationBlockNumber we will never submit the config.
+	if l1BlockNumber < activationBlockNumber && activationBlockNumber-l1BlockNumber > snkpr.config.Shuttermint.DKGStartBlockDelta {
 		log.Info().Interface("keyper-set", keyperSet).
 			Uint64("l1-block-number", l1BlockNumber).
 			Uint64("dkg-start-delta", snkpr.config.Shuttermint.DKGStartBlockDelta).