connection.go      |  6 +++---
 connection_test.go | 17 ++++++++++++++---
 torrent.go         |  3 +++

diff --git a/connection.go b/connection.go
index 5493714bdabee9b177b031e1f22ab56088db05ca..fbc888c3fbedf766783d3ee50f61c5d40743a151 100644
--- a/connection.go
+++ b/connection.go
@@ -942,15 +942,15 @@ 	} else {
 		unexpectedChunksReceived.Add(1)
 	}
 
-	index := int(req.Index)
-	piece := &t.pieces[index]
-
 	// Do we actually want this chunk?
 	if !t.wantPiece(req) {
 		unwantedChunksReceived.Add(1)
 		c.UnwantedChunksReceived++
 		return
 	}
+
+	index := int(req.Index)
+	piece := &t.pieces[index]
 
 	c.UsefulChunksReceived++
 	c.lastUsefulChunkReceived = time.Now()
diff --git a/connection_test.go b/connection_test.go
index 31ddbe141822f8bb7407e83530e6f43e1c72ead9..48fb4f5f9a447c3cae090e596e7d02c8b29cba53 100644
--- a/connection_test.go
+++ b/connection_test.go
@@ -16,7 +16,7 @@ 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 
 	"github.com/anacrolix/torrent/metainfo"
-	"github.com/anacrolix/torrent/peer_protocol"
+	pp "github.com/anacrolix/torrent/peer_protocol"
 	"github.com/anacrolix/torrent/storage"
 )
 
@@ -157,8 +157,8 @@ 			mrlErr <- err
 		}
 		close(mrlErr)
 	}()
-	msg := peer_protocol.Message{
-		Type:  peer_protocol.Piece,
+	msg := pp.Message{
+		Type:  pp.Piece,
 		Piece: make([]byte, defaultChunkSize),
 	}
 	wb, err := msg.MarshalBinary()
@@ -178,3 +178,14 @@ 	w.Close()
 	require.NoError(b, <-mrlErr)
 	require.EqualValues(b, b.N, cn.UsefulChunksReceived)
 }
+
+func TestConnectionReceiveBadChunkIndex(t *testing.T) {
+	cn := connection{
+		t: &Torrent{},
+	}
+	require.False(t, cn.t.haveInfo())
+	assert.NotPanics(t, func() { cn.receiveChunk(&pp.Message{}) })
+	cn.t.info = &metainfo.Info{}
+	require.True(t, cn.t.haveInfo())
+	assert.NotPanics(t, func() { cn.receiveChunk(&pp.Message{}) })
+}
diff --git a/torrent.go b/torrent.go
index d0f81fd7f1bc3a2628ca5abd3616b0d486b74e1e..2577960ca3eea6bf6cd5c78778c4c2e7b35a12b7 100644
--- a/torrent.go
+++ b/torrent.go
@@ -734,6 +734,9 @@ func (t *Torrent) wantPieceIndex(index int) bool {
 	if !t.haveInfo() {
 		return false
 	}
+	if index < 0 || index >= t.numPieces() {
+		return false
+	}
 	p := &t.pieces[index]
 	if p.QueuedForHash {
 		return false