From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id DAD0AC7618E for ; Fri, 21 Apr 2023 03:33:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233574AbjDUDdn (ORCPT ); Thu, 20 Apr 2023 23:33:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41690 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233534AbjDUDda (ORCPT ); Thu, 20 Apr 2023 23:33:30 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C1F1F213D for ; Thu, 20 Apr 2023 20:33:26 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 2A10664D8E for ; Fri, 21 Apr 2023 03:33:26 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 06B84C433EF; Fri, 21 Apr 2023 03:33:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1682048005; bh=QNCwA1j6xFn1l3sCa3C+089KKEf2uImL+6/5gQiyowU=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=QGZAgL1urdvcHYAlsnpIf82vGpjIuf9++/xW0HtTIc2mRf+e7eu3EP/vTK4tgze2x 7z18LfdvHCQhap96EFBNOZWdZqP9hE7aCP1DbUB6pN7IgylZ1mGKdtjSyRkxeWmQig 2R0UkOu7rvH3vQ8/akpYT7LOwtxiAFu/LYNGS8M57rf9uy274ta1ZXUrmADmUwRtEL GkFe6YwE7sqXOvjoI8fZI4XXFFl0CNvefD95UNtptYhEAMNIJXCH8YPL7uceNN3Knl kF0z9N1oM3pDhX9hWL8togJ3XH66CNcGuNvtHwimKBack7wwGih1GKokp4LMP+Iqky jOMlwMmWKB8bw== Date: Thu, 20 Apr 2023 20:33:24 -0700 From: Jakub Kicinski To: Kuniyuki Iwashima Cc: "David S. Miller" , Eric Dumazet , Paolo Abeni , Patrick McHardy , Pablo Neira Ayuso , Christophe Ricard , Johannes Berg , David Ahern , Kuniyuki Iwashima , , Brad Spencer Subject: Re: [PATCH v2 net] netlink: Use copy_to_user() for optval in netlink_getsockopt(). Message-ID: <20230420203324.04c50e8d@kernel.org> In-Reply-To: <20230420233351.77166-1-kuniyu@amazon.com> References: <20230420233351.77166-1-kuniyu@amazon.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Thu, 20 Apr 2023 16:33:51 -0700 Kuniyuki Iwashima wrote: > diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c > index f365dfdd672d..5c0d17b3984c 100644 > --- a/net/netlink/af_netlink.c > +++ b/net/netlink/af_netlink.c > @@ -1742,7 +1742,7 @@ static int netlink_getsockopt(struct socket *sock, int level, int optname, > { > struct sock *sk = sock->sk; > struct netlink_sock *nlk = nlk_sk(sk); > - int len, val, err; > + int len, val; > > if (level != SOL_NETLINK) > return -ENOPROTOOPT; > @@ -1753,40 +1753,27 @@ static int netlink_getsockopt(struct socket *sock, int level, int optname, > return -EINVAL; > > switch (optname) { > - case NETLINK_PKTINFO: > + case NETLINK_LIST_MEMBERSHIPS: > + break; > + default: > if (len < sizeof(int)) > return -EINVAL; > len = sizeof(int); > + } > - err = 0; > break; > default: > - err = -ENOPROTOOPT; > + return -ENOPROTOOPT; > } > - return err; > + > + if (put_user(len, optlen) || > + copy_to_user(optval, &val, len)) > + return -EFAULT; Maybe this is a nit pick but we'd unnecessarily change the return value to unknown opts when len < 4, from -ENOPROTOOPT to -EINVAL, right? How about we do: unsigned int flag; flag = 0; switch (optname) { case NETLINK_PKTINFO: flag = NETLINK_F_RECV_PKTINFO; break; case NETLINK_BROADCAST_ERROR: flag = NETLINK_F_BROADCAST_SEND_ERROR; break; ... case NETLINK_LIST_MEMBERSHIPS: { ... default: return -ENOPROTOOPT; } if (flag) { if (len < sizeof(int)) return -EINVAL; len = sizeof(int); val = nlk->flags & flag ? 1 : 0; if (put_user(len, optlen) || copy_to_user(optval, &val, len)) return -EFAULT; ... }