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 6197FC4167B for ; Mon, 7 Mar 2022 09:29:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237901AbiCGJ2c (ORCPT ); Mon, 7 Mar 2022 04:28:32 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40628 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236996AbiCGJ0b (ORCPT ); Mon, 7 Mar 2022 04:26:31 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6F02459392; Mon, 7 Mar 2022 01:24:24 -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 B1CFAB810BF; Mon, 7 Mar 2022 09:24:20 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id E355CC340E9; Mon, 7 Mar 2022 09:24:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1646645059; bh=Yk+pDMgLT5V/AY4reUaCFCWuiZim70mksUsnxzQDr4I=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=RWSCLaqXSX89n6q0OXGclQnJnJ2imJji5Xakqreen7JGjsvp1BQoB5JP9O62JKHSj /yNGNX1V8itXTHl46i8S2lcIXfT4vRN0Vrj9ATuu/6qYFxZkmb2WGsN+hSyy31az+s blsT9I/2nPULlke3gkyx6ef3Tw/dEgLgQiKA7IPE= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Sven Eckelmann , Simon Wunderlich Subject: [PATCH 4.19 24/51] batman-adv: Request iflink once in batadv_get_real_netdevice Date: Mon, 7 Mar 2022 10:18:59 +0100 Message-Id: <20220307091637.680870706@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220307091636.988950823@linuxfoundation.org> References: <20220307091636.988950823@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: linux-kernel@vger.kernel.org From: Sven Eckelmann commit 6116ba09423f7d140f0460be6a1644dceaad00da upstream. There is no need to call dev_get_iflink multiple times for the same net_device in batadv_get_real_netdevice. 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: 5ed4a460a1d3 ("batman-adv: additional checks for virtual interfaces on top of WiFi") 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 @@ -228,14 +228,16 @@ static struct net_device *batadv_get_rea struct net_device *real_netdev = NULL; struct net *real_net; struct net *net; - int ifindex; + int iflink; ASSERT_RTNL(); if (!netdev) return NULL; - if (netdev->ifindex == dev_get_iflink(netdev)) { + iflink = dev_get_iflink(netdev); + + if (netdev->ifindex == iflink) { dev_hold(netdev); return netdev; } @@ -245,9 +247,8 @@ static struct net_device *batadv_get_rea goto out; net = dev_net(hard_iface->soft_iface); - ifindex = dev_get_iflink(netdev); real_net = batadv_getlink_net(netdev, net); - real_netdev = dev_get_by_index(real_net, ifindex); + real_netdev = dev_get_by_index(real_net, iflink); out: if (hard_iface)