From patchwork Mon Mar 14 11:34:18 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 551809 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 E6667C433F5 for ; Mon, 14 Mar 2022 11:35:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238945AbiCNLg2 (ORCPT ); Mon, 14 Mar 2022 07:36:28 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35798 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239104AbiCNLgZ (ORCPT ); Mon, 14 Mar 2022 07:36:25 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DB8F9427D5; Mon, 14 Mar 2022 04:35:13 -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 ams.source.kernel.org (Postfix) with ESMTPS id 78602B80DC3; Mon, 14 Mar 2022 11:35:12 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id E3B24C340E9; Mon, 14 Mar 2022 11:35:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1647257711; bh=fvRsoPCUiahNyopVck/eVLU2wDj0nJM1jv8ooa+BzaU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=xnu6B8Ut4GnDP2wVe4G8/e4ntI9jFU1rhLcysDArvvun6kGzJorRjIfBFrzcuzX04 0lZZnu8dDetyhFyjM1ty8qXD1Xe1BIu37TVw7+n87ZMTsT8zAu1x/NVyQ6k1gM6vP5 nYM3sgB7x0NZJGFWLCjHyaYAahoazA6FuMD2WKEA= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Sven Eckelmann , Simon Wunderlich Subject: [PATCH 4.9 17/20] batman-adv: Request iflink once in batadv-on-batadv check Date: Mon, 14 Mar 2022 12:34:18 +0100 Message-Id: <20220314112731.005195768@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220314112730.388955049@linuxfoundation.org> References: <20220314112730.388955049@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Sven Eckelmann commit 690bb6fb64f5dc7437317153902573ecad67593d upstream. There is no need to call dev_get_iflink multiple times for the same net_device in batadv_is_on_batman_iface. And since some of the .ndo_get_iflink callbacks are dynamic (for example via RCUs like in vxcan_get_iflink), it could easily happen that the returned values are not stable. The pre-checks before __dev_get_by_index are then of course bogus. Fixes: b7eddd0b3950 ("batman-adv: prevent using any virtual device created on batman-adv as hard-interface") Signed-off-by: Sven Eckelmann Signed-off-by: Simon Wunderlich [ bp: 4.9 backported: adjust context. ] Signed-off-by: Sven Eckelmann Signed-off-by: Greg Kroah-Hartman --- net/batman-adv/hard-interface.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) --- a/net/batman-adv/hard-interface.c +++ b/net/batman-adv/hard-interface.c @@ -155,22 +155,23 @@ static bool batadv_is_on_batman_iface(co struct net *net = dev_net(net_dev); struct net_device *parent_dev; const struct net *parent_net; + int iflink; bool ret; /* check if this is a batman-adv mesh interface */ if (batadv_softif_is_valid(net_dev)) return true; + iflink = dev_get_iflink(net_dev); + /* no more parents..stop recursion */ - if (dev_get_iflink(net_dev) == 0 || - dev_get_iflink(net_dev) == net_dev->ifindex) + if (iflink == 0 || iflink == net_dev->ifindex) return false; parent_net = batadv_getlink_net(net_dev, net); /* recurse over the parent device */ - parent_dev = __dev_get_by_index((struct net *)parent_net, - dev_get_iflink(net_dev)); + parent_dev = __dev_get_by_index((struct net *)parent_net, iflink); /* if we got a NULL parent_dev there is something broken.. */ if (!parent_dev) { pr_err("Cannot find parent device\n");