1 files changed, 12 insertions, 0 deletions
diff --git a/roseh.moe.go b/roseh.moe.go
index 59878c4..02428f3 100644
--- a/roseh.moe.go
+++ b/roseh.moe.go
@@ -261,6 +261,12 @@ func writeHoleFile(part *multipart.Part) (string, error) {
 	return hole, f.Close()
 }
 
+func decryptedSize(size int64) int64 {
+	size -= 32
+	segments := (size + (blockSize - 1)) / blockSize
+	return size - segments*16
+}
+
 var errNoHole = errors.New("no such hole")
 
 func readHoleFile(w http.ResponseWriter, hole string) error {
@@ -277,6 +283,10 @@ func readHoleFile(w http.ResponseWriter, hole string) error {
 		return err
 	}
 	defer f.Close()
+	stat, err := f.Stat()
+	if err != nil {
+		return err
+	}
 	r := oae2.NewReader(f, encryptionKey, blockSize)
 	buf := make([]byte, 8)
 	if _, err := io.ReadFull(r, buf); err != nil {
@@ -289,6 +299,8 @@ func readHoleFile(w http.ResponseWriter, hole string) error {
 	}
 	fileName := string(buf)
 	w.Header().Set("Content-Disposition", "attachment; filename*=UTF-8''"+fileName)
+	fileSize := decryptedSize(stat.Size()) - 8 - int64(fileNameLen)
+	w.Header().Set("Content-Length", strconv.FormatInt(fileSize, 10))
 	_, err = io.Copy(w, r)
 	return err
 }