From 779c923a05d273d9312922962e9d9ed4c850ff09 Mon Sep 17 00:00:00 2001
From: hannahhoward <hannah@hannahhoward.net>
Date: Tue, 13 Nov 2018 11:25:30 -0800
Subject: [PATCH] fix(Receiver): Ignore unwanted blocks

If Bitswap receives a block that isn't in it's wantlist, is should ignore it

fix #21 fix #22
---
 bitswap.go      |  6 ++++++
 bitswap_test.go | 33 +++++++++++++++++++++++++++++++++
 2 files changed, 39 insertions(+)

diff --git a/bitswap.go b/bitswap.go
index 942679d4..4b72b52d 100644
--- a/bitswap.go
+++ b/bitswap.go
@@ -388,6 +388,7 @@ func (bs *Bitswap) ReceiveMessage(ctx context.Context, p peer.ID, incoming bsmsg
 
 	wg := sync.WaitGroup{}
 	for _, block := range iblocks {
+
 		wg.Add(1)
 		go func(b blocks.Block) { // TODO: this probably doesnt need to be a goroutine...
 			defer wg.Done()
@@ -396,6 +397,11 @@ func (bs *Bitswap) ReceiveMessage(ctx context.Context, p peer.ID, incoming bsmsg
 
 			log.Debugf("got block %s from %s", b, p)
 
+			// skip received blocks that are not in the wantlist
+			if _, contains := bs.wm.wl.Contains(b.Cid()); !contains {
+				return
+			}
+
 			if err := bs.receiveBlockFrom(b, p); err != nil {
 				log.Warningf("ReceiveMessage recvBlockFrom error: %s", err)
 			}
diff --git a/bitswap_test.go b/bitswap_test.go
index 715958eb..d55fd073 100644
--- a/bitswap_test.go
+++ b/bitswap_test.go
@@ -9,6 +9,7 @@ import (
 	"time"
 
 	decision "github.com/ipfs/go-bitswap/decision"
+	"github.com/ipfs/go-bitswap/message"
 	tn "github.com/ipfs/go-bitswap/testnet"
 
 	blocks "github.com/ipfs/go-block-format"
@@ -98,6 +99,38 @@ func TestGetBlockFromPeerAfterPeerAnnounces(t *testing.T) {
 	}
 }
 
+func TestUnwantedBlockNotAdded(t *testing.T) {
+
+	net := tn.VirtualNetwork(mockrouting.NewServer(), delay.Fixed(kNetworkDelay))
+	block := blocks.NewBlock([]byte("block"))
+	bsMessage := message.New(true)
+	bsMessage.AddBlock(block)
+
+	g := NewTestSessionGenerator(net)
+	defer g.Close()
+
+	peers := g.Instances(2)
+	hasBlock := peers[0]
+	defer hasBlock.Exchange.Close()
+
+	if err := hasBlock.Exchange.HasBlock(block); err != nil {
+		t.Fatal(err)
+	}
+
+	doesNotWantBlock := peers[1]
+	defer doesNotWantBlock.Exchange.Close()
+
+	ctx, cancel := context.WithTimeout(context.Background(), time.Second)
+	defer cancel()
+
+	doesNotWantBlock.Exchange.ReceiveMessage(ctx, hasBlock.Peer, bsMessage)
+
+	blockInStore, err := doesNotWantBlock.blockstore.Has(block.Cid())
+	if err != nil || blockInStore {
+		t.Fatal("Unwanted block added to block store")
+	}
+}
+
 func TestLargeSwarm(t *testing.T) {
 	if testing.Short() {
 		t.SkipNow()