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 4E525C433EF for ; Mon, 7 Mar 2022 09:45:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230512AbiCGJpy (ORCPT ); Mon, 7 Mar 2022 04:45:54 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57090 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237843AbiCGJhe (ORCPT ); Mon, 7 Mar 2022 04:37:34 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 30AD06E4C1; Mon, 7 Mar 2022 01:31:39 -0800 (PST) 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 57013B80F9F; Mon, 7 Mar 2022 09:31:27 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id BE822C340E9; Mon, 7 Mar 2022 09:31:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1646645486; bh=HIvLy0yJIAmswdOY7HiiFoaeqJ0zxBGgTZ9SQwULyQg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=fVSXrMAysrGHtkouyRxXFRQb/t1it2EKATt5sqcQ7m1JynbrW5bjwHANaRI2JrxJV Puc/t31PwI3GLo+MNkBEwYsFjAQawSojP+3AHYOPiAndmrVa5ocqFMeIDy2hHrQumH ErbCeVnhVrZH6mpfDpDyBRxZ/HHT15BqCXsc99r0= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Sven Eckelmann , Simon Wunderlich Subject: [PATCH 5.10 046/105] batman-adv: Request iflink once in batadv-on-batadv check Date: Mon, 7 Mar 2022 10:18:49 +0100 Message-Id: <20220307091645.480919377@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220307091644.179885033@linuxfoundation.org> References: <20220307091644.179885033@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 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 @@ -151,22 +151,23 @@ static bool batadv_is_on_batman_iface(co struct net *net = dev_net(net_dev); struct net_device *parent_dev; 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");