From: Matt Joiner <anacrolix@gmail.com>
Date: Tue, 22 Nov 2016 03:20:48 +0000 (+1100)
Subject: Don't accept pieces with bad indexes
X-Git-Tag: v1.0.0~533
X-Git-Url: http://www.git.stargrave.org/?a=commitdiff_plain;h=90ca45dd2d73a2dbc0843f11f75fadfc08cc6eb4;p=btrtrc.git

Don't accept pieces with bad indexes

Fixes #132
---

diff --git a/connection.go b/connection.go
index 5493714b..fbc888c3 100644
--- a/connection.go
+++ b/connection.go
@@ -942,9 +942,6 @@ func (c *connection) receiveChunk(msg *pp.Message) {
 		unexpectedChunksReceived.Add(1)
 	}
 
-	index := int(req.Index)
-	piece := &t.pieces[index]
-
 	// Do we actually want this chunk?
 	if !t.wantPiece(req) {
 		unwantedChunksReceived.Add(1)
@@ -952,6 +949,9 @@ func (c *connection) receiveChunk(msg *pp.Message) {
 		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 31ddbe14..48fb4f5f 100644
--- a/connection_test.go
+++ b/connection_test.go
@@ -16,7 +16,7 @@ import (
 	"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 @@ func BenchmarkConnectionMainReadLoop(b *testing.B) {
 		}
 		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 @@ func BenchmarkConnectionMainReadLoop(b *testing.B) {
 	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 d0f81fd7..2577960c 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