fix bug:404 when downloading other user's public attachment

routers/repo/attachment.go

@@ -139,7 +139,7 @@ func GetAttachment(ctx *context.Context) {
 	}
 
 	if repository == nil { //If not linked
-		if !(ctx.IsSigned && attach.UploaderID == ctx.User.ID) { //We block if not the uploader
+		if !(ctx.IsSigned && attach.UploaderID == ctx.User.ID) && attach.IsPrivate { //We block if not the uploader
 			ctx.Error(http.StatusNotFound)
 			return
 		}