From patchwork Tue Apr 5 13:42:36 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Florent Fourcot X-Patchwork-Id: 12801893 X-Patchwork-Delegate: kuba@kernel.org 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 0E98BC4167E for ; Tue, 5 Apr 2022 20:10:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1356498AbiDEUDt (ORCPT ); Tue, 5 Apr 2022 16:03:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60152 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1391792AbiDEPfK (ORCPT ); Tue, 5 Apr 2022 11:35:10 -0400 Received: from olfflo.fourcot.fr (fourcot.fr [217.70.191.14]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7B84713EFA2 for ; Tue, 5 Apr 2022 06:43:03 -0700 (PDT) From: Florent Fourcot To: netdev@vger.kernel.org Cc: cong.wang@bytedance.com, edumazet@google.com, Florent Fourcot , Brian Baboch Subject: [PATCH v3 net-next 3/4] rtnetlink: return ENODEV when ifname does not exist and group is given Date: Tue, 5 Apr 2022 15:42:36 +0200 Message-Id: <20220405134237.16533-3-florent.fourcot@wifirst.fr> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20220405134237.16533-1-florent.fourcot@wifirst.fr> References: <20220405134237.16533-1-florent.fourcot@wifirst.fr> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org When the interface does not exist, and a group is given, the given parameters are being set to all interfaces of the given group. The given IFNAME/ALT_IF_NAME are being ignored in that case. That can be dangerous since a typo (or a deleted interface) can produce weird side effects for caller: Case 1: IFLA_IFNAME=valid_interface IFLA_GROUP=1 MTU=1234 Case 1 will update MTU and group of the given interface "valid_interface". Case 2: IFLA_IFNAME=doesnotexist IFLA_GROUP=1 MTU=1234 Case 2 will update MTU of all interfaces in group 1. IFLA_IFNAME is ignored in this case This behaviour is not consistent and dangerous. In order to fix this issue, we now return ENODEV when the given IFNAME does not exist. Changes in v3: * Use a boolean to have condition duplication Signed-off-by: Florent Fourcot Signed-off-by: Brian Baboch --- net/core/rtnetlink.c | 18 ++++++++++++++---- 1 file changed, 14 insertions(+), 4 deletions(-) diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c index 33dbeed7e531..e93f4058cf08 100644 --- a/net/core/rtnetlink.c +++ b/net/core/rtnetlink.c @@ -3279,6 +3279,7 @@ static int __rtnl_newlink(struct sk_buff *skb, struct nlmsghdr *nlh, struct net *dest_net, *link_net; struct nlattr **slave_data; char kind[MODULE_NAME_LEN]; + bool link_lookup = false; struct net_device *dev; struct ifinfomsg *ifm; char ifname[IFNAMSIZ]; @@ -3298,12 +3299,15 @@ static int __rtnl_newlink(struct sk_buff *skb, struct nlmsghdr *nlh, return err; ifm = nlmsg_data(nlh); - if (ifm->ifi_index > 0) + if (ifm->ifi_index > 0) { + link_lookup = true; dev = __dev_get_by_index(net, ifm->ifi_index); - else if (tb[IFLA_IFNAME] || tb[IFLA_ALT_IFNAME]) + } else if (tb[IFLA_IFNAME] || tb[IFLA_ALT_IFNAME]) { + link_lookup = true; dev = rtnl_dev_get(net, tb); - else + } else { dev = NULL; + } master_dev = NULL; m_ops = NULL; @@ -3405,8 +3409,14 @@ static int __rtnl_newlink(struct sk_buff *skb, struct nlmsghdr *nlh, return do_setlink(skb, dev, ifm, extack, tb, status); } + if (!(nlh->nlmsg_flags & NLM_F_CREATE)) { - if (ifm->ifi_index == 0 && tb[IFLA_GROUP]) + /* No dev found and NLM_F_CREATE not set. Requested dev does not exist, + * or it's for a group + */ + if (link_lookup) + return -ENODEV; + if (tb[IFLA_GROUP]) return rtnl_group_changelink(skb, net, nla_get_u32(tb[IFLA_GROUP]), ifm, extack, tb);