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 8CC17C433F5 for ; Mon, 7 Mar 2022 09:25:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236935AbiCGJ0i (ORCPT ); Mon, 7 Mar 2022 04:26:38 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36206 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236975AbiCGJ0U (ORCPT ); Mon, 7 Mar 2022 04:26:20 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 10BFB5C37F; Mon, 7 Mar 2022 01:24:17 -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 dfw.source.kernel.org (Postfix) with ESMTPS id 7087560C00; Mon, 7 Mar 2022 09:24:16 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6DF35C340F3; Mon, 7 Mar 2022 09:24:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1646645055; bh=R9TpK/gR5sMqKErCceGZ4rnFD3PKRmEmm/09mgjmz30=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=PrAXP3H6LeGptWAwbicBktO/GSmkOOfnCp6q7KiqBX0oH+ClPZT951YdgoTpyYKOz VnKOxaualozYx+mjI0lXkeM0/wsuPWIEmNCx18d2MNjQ+NmP29CsmxcwCM+EBEvhie dKZmdFvHbU7YHpw3TbDYH1xCySWWaynM1U1mpOfc= 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 23/51] batman-adv: Request iflink once in batadv-on-batadv check Date: Mon, 7 Mar 2022 10:18:58 +0100 Message-Id: <20220307091637.652869787@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: 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 @@ -162,22 +162,23 @@ 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");