Fix a crash when receiving a request when we don't yet have the torrent info

diff --git a/connection.go b/connection.go
index 397be949c00c3e6bb0b8163c38ab2623be85be42..8a137e959128ecaecdc90b1d5de894b4cc816a3d 100644 (file)
--- a/connection.go
+++ b/connection.go
@@ -1025,10 +1025,6 @@ func (c *connection) reject(r request) {
 
 func (c *connection) onReadRequest(r request) error {
        requestedChunkLengths.Add(strconv.FormatUint(r.Length.Uint64(), 10), 1)
-       if r.Begin+r.Length > c.t.pieceLength(pieceIndex(r.Index)) {
-               torrent.Add("bad requests received", 1)
-               return errors.New("bad request")
-       }
        if _, ok := c.PeerRequests[r]; ok {
                torrent.Add("duplicate requests received", 1)
                return nil
@@ -1056,6 +1052,11 @@ func (c *connection) onReadRequest(r request) error {
                requestsReceivedForMissingPieces.Add(1)
                return fmt.Errorf("peer requested piece we don't have: %v", r.Index.Int())
        }
+       // Check this after we know we have the piece, so that the piece length will be known.
+       if r.Begin+r.Length > c.t.pieceLength(pieceIndex(r.Index)) {
+               torrent.Add("bad requests received", 1)
+               return errors.New("bad request")
+       }
        if c.PeerRequests == nil {
                c.PeerRequests = make(map[request]struct{}, maxRequests)
        }