From patchwork Fri Apr 15 16:53:27 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Florent Fourcot X-Patchwork-Id: 12815202 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 C3738C433FE for ; Fri, 15 Apr 2022 16:53:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1355984AbiDOQ4W (ORCPT ); Fri, 15 Apr 2022 12:56:22 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43148 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1355981AbiDOQ4T (ORCPT ); Fri, 15 Apr 2022 12:56:19 -0400 Received: from olfflo.fourcot.fr (fourcot.fr [217.70.191.14]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 669F1972A1 for ; Fri, 15 Apr 2022 09:53:50 -0700 (PDT) From: Florent Fourcot To: netdev@vger.kernel.org Cc: cong.wang@bytedance.com, edumazet@google.com, Florent Fourcot , Brian Baboch Subject: [PATCH v5 net-next 1/4] rtnetlink: return ENODEV when ifname does not exist and group is given Date: Fri, 15 Apr 2022 18:53:27 +0200 Message-Id: <20220415165330.10497-2-florent.fourcot@wifirst.fr> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20220415165330.10497-1-florent.fourcot@wifirst.fr> References: <20220415165330.10497-1-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. 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 8bf770a7261e..2f538ab512d0 100644 --- a/net/core/rtnetlink.c +++ b/net/core/rtnetlink.c @@ -3326,6 +3326,7 @@ static int __rtnl_newlink(struct sk_buff *skb, struct nlmsghdr *nlh, struct ifinfomsg *ifm; char ifname[IFNAMSIZ]; struct nlattr **data; + bool link_specified; int err; #ifdef CONFIG_MODULES @@ -3346,12 +3347,16 @@ static int __rtnl_newlink(struct sk_buff *skb, struct nlmsghdr *nlh, ifname[0] = '\0'; ifm = nlmsg_data(nlh); - if (ifm->ifi_index > 0) + if (ifm->ifi_index > 0) { + link_specified = 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_specified = true; dev = rtnl_dev_get(net, NULL, tb[IFLA_ALT_IFNAME], ifname); - else + } else { + link_specified = false; dev = NULL; + } master_dev = NULL; m_ops = NULL; @@ -3454,7 +3459,12 @@ static int __rtnl_newlink(struct sk_buff *skb, struct nlmsghdr *nlh, } 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_specified) + return -ENODEV; + if (tb[IFLA_GROUP]) return rtnl_group_changelink(skb, net, nla_get_u32(tb[IFLA_GROUP]), ifm, extack, tb);