misc.go    | 11 +++++++++++
 torrent.go |  5 +++++

diff --git a/misc.go b/misc.go
index c567f68d5631d320732873890a7c8372d4d9c486..3cf1b8ee75b1dba2d78dca0de4d9a43c0d9d07d3 100644
--- a/misc.go
+++ b/misc.go
@@ -6,6 +6,7 @@ 	"errors"
 	"fmt"
 	"time"
 
+	"github.com/anacrolix/torrent/metainfo"
 	pp "github.com/anacrolix/torrent/peer_protocol"
 )
 
@@ -107,3 +108,13 @@ 		panic("invalid request")
 	}
 	return
 }
+
+func validateInfo(info *metainfo.Info) error {
+	if len(info.Pieces)%20 != 0 {
+		return errors.New("pieces has invalid length")
+	}
+	if int((info.TotalLength()+info.PieceLength-1)/info.PieceLength) != info.NumPieces() {
+		return errors.New("piece count and file lengths are at odds")
+	}
+	return nil
+}
diff --git a/torrent.go b/torrent.go
index ef82e992f604f7f0f6e08221ecd5e7b1a987427d..e32175e9429a4ab74159334aa95e326cc92da89c 100644
--- a/torrent.go
+++ b/torrent.go
@@ -208,6 +208,11 @@ }
 
 // Called when metadata for a torrent becomes available.
 func (t *torrent) setMetadata(md *metainfo.Info, infoBytes []byte, eventLocker sync.Locker) (err error) {
+	err = validateInfo(md)
+	if err != nil {
+		err = fmt.Errorf("bad info: %s", err)
+		return
+	}
 	t.Info = md
 	t.length = 0
 	for _, f := range t.Info.UpvertedFiles() {