From 0744e8ebc0367d5e8c35c02880ada3a0515117b4 Mon Sep 17 00:00:00 2001
From: Ori Newman <orinewman1@gmail.com>
Date: Mon, 15 Jun 2020 16:08:25 +0300
Subject: [PATCH] [NOD-1042] Ignore very high orphans (#761)

* [NOD-530] Remove coinbase inputs and add blue score to payload

* [NOD-1042] Ignore very high orphans

* [NOD-1042] Add ban score to an orphan with malformed blue score

* [NOD-1042] Fix log
---
 netsync/manager.go | 19 +++++++++++++++++++
 peer/banscores.go  |  7 ++++---
 2 files changed, 23 insertions(+), 3 deletions(-)

diff --git a/netsync/manager.go b/netsync/manager.go
index 977f8cfb4..55481a888 100644
--- a/netsync/manager.go
+++ b/netsync/manager.go
@@ -532,6 +532,25 @@ func (sm *SyncManager) handleBlockMsg(bmsg *blockMsg) {
 	}
 
 	if isOrphan {
+		blueScore, err := bmsg.block.BlueScore()
+		if err != nil {
+			log.Errorf("Received an orphan block %s with malformed blue score from %s. Disconnecting...",
+				blockHash, peer)
+			peer.AddBanScoreAndPushRejectMsg(wire.CmdBlock, wire.RejectInvalid, blockHash,
+				peerpkg.BanScoreMalformedBlueScoreInOrphan, 0,
+				fmt.Sprintf("Received an orphan block %s with malformed blue score", blockHash))
+			return
+		}
+
+		const maxOrphanBlueScoreDiff = 10000
+		selectedTipBlueScore := sm.dag.SelectedTipBlueScore()
+		if blueScore > selectedTipBlueScore+maxOrphanBlueScoreDiff {
+			log.Infof("Orphan block %s has blue score %d and the selected tip blue score is "+
+				"%d. Ignoring orphans with a blue score difference from the selected tip greater than %d",
+				blockHash, blueScore, selectedTipBlueScore, maxOrphanBlueScoreDiff)
+			return
+		}
+
 		// Request the parents for the orphan block from the peer that sent it.
 		missingAncestors, err := sm.dag.GetOrphanMissingAncestorHashes(blockHash)
 		if err != nil {
diff --git a/peer/banscores.go b/peer/banscores.go
index d5a7dc1d8..f4529c19a 100644
--- a/peer/banscores.go
+++ b/peer/banscores.go
@@ -2,9 +2,10 @@ package peer
 
 // Ban scores for misbehaving nodes
 const (
-	BanScoreUnrequestedBlock = 100
-	BanScoreInvalidBlock     = 100
-	BanScoreInvalidInvBlock  = 100
+	BanScoreUnrequestedBlock           = 100
+	BanScoreInvalidBlock               = 100
+	BanScoreInvalidInvBlock            = 100
+	BanScoreMalformedBlueScoreInOrphan = 100
 
 	BanScoreUnrequestedSelectedTip = 20
 	BanScoreUnrequestedTx          = 20