From patchwork Sun Feb 27 23:52:56 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sven Eckelmann X-Patchwork-Id: 18462 X-Patchwork-Delegate: sw@simonwunderlich.de Return-Path: X-Original-To: patchwork@open-mesh.org Delivered-To: patchwork@open-mesh.org Received: from diktynna.open-mesh.org (localhost [IPv6:::1]) by diktynna.open-mesh.org (Postfix) with ESMTP id 92ECC842F2; Mon, 28 Feb 2022 00:53:22 +0100 (CET) Received: from dvalin.narfation.org (dvalin.narfation.org [213.160.73.56]) by diktynna.open-mesh.org (Postfix) with ESMTPS id 1D8A884264 for ; Mon, 28 Feb 2022 00:53:20 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=narfation.org; s=20121; t=1646005999; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=t0uHVlbNGevCMIC6Crrz5bYotHCXjwjX+/1e+QLHV/k=; b=A5PIPpUs8t5w0QfcI0ziMPEeHNfhReYLK7qfolFrmT7jXHHwp2vq1xT26I6R7/ekyOBR0I O0EfKbXh5/fwY1W7acs6q+baVfXU3rJQr/h0hjx61HCrs4EdW+idkTjKChCtgFUW68KWaV R2NAxjOhdnWvhP69KY2oJuhuH8ZQD+c= From: Sven Eckelmann To: b.a.t.m.a.n@lists.open-mesh.org Subject: [RFC PATCH 3/4] batman-adv: Don't expect inter-netns unique iflink indices Date: Mon, 28 Feb 2022 00:52:56 +0100 Message-Id: <20220227235257.1324636-3-sven@narfation.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20220227235257.1324636-1-sven@narfation.org> References: <20220227235257.1324636-1-sven@narfation.org> MIME-Version: 1.0 ARC-Authentication-Results: i=1; diktynna.open-mesh.org; dkim=pass header.d=narfation.org header.s=20121 header.b=A5PIPpUs; dmarc=pass (policy=none) header.from=narfation.org; spf=pass (diktynna.open-mesh.org: domain of sven@narfation.org designates 213.160.73.56 as permitted sender) smtp.mailfrom=sven@narfation.org ARC-Seal: i=1; s=20121; d=open-mesh.org; t=1646006000; a=rsa-sha256; cv=none; b=bmN4MzCRm1Ig7vCT6BtMtb4ZWZ5iqo9ZLOG+6K+D00P0iRc1d16gYCacMmY+YoiAr/BYef OyDsNZRqSplV6GkErC3w6MB5ufpAUK4bZNqsMZxa8gpvy9aUtJIsrjUSH97bKidwJhft7v VFs9nycanH5Z0RhOYaZQYG9qSfhUiLg= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=open-mesh.org; s=20121; t=1646006000; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=t0uHVlbNGevCMIC6Crrz5bYotHCXjwjX+/1e+QLHV/k=; b=eyDUeS/PGRe1uhtqQaD18TDcXGXCY2dSTEeQbih0DtxG8T4FFgqJojBlmfzqq3Q8o3GNjM upGg28YQwTHu+158s4uy/TS/tXRGJHgdfkvBwViPzGSrrU/fPXlg9fS3pA42dNjS2VWv/1 1kfRzpXiNSF41VXSRcYjL/wKnD3c7GI= Message-ID-Hash: HZMHGK6S7TOTFS7MTFWGZYIWLYC5VR2C X-Message-ID-Hash: HZMHGK6S7TOTFS7MTFWGZYIWLYC5VR2C X-MailFrom: sven@narfation.org X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; emergency; loop; banned-address; member-moderation; header-match-b.a.t.m.a.n.lists.open-mesh.org-0; header-match-b.a.t.m.a.n.lists.open-mesh.org-1; nonmember-moderation; administrivia; implicit-dest; max-recipients; max-size; news-moderation; no-subject; suspicious-header CC: Sabrina Dubroca X-Mailman-Version: 3.2.1 Precedence: list Reply-To: The list for a Better Approach To Mobile Ad-hoc Networking List-Id: The list for a Better Approach To Mobile Ad-hoc Networking Archived-At: List-Archive: List-Help: List-Post: List-Subscribe: List-Unsubscribe: The ifindex doesn't have to be unique for multiple network namespaces on the same machine. $ ip netns add test1 $ ip -net test1 link add dummy1 type dummy $ ip netns add test2 $ ip -net test2 link add dummy2 type dummy $ ip -net test1 link show dev dummy1 6: dummy1: mtu 1500 qdisc noop state DOWN mode DEFAULT group default qlen 1000 link/ether 96:81:55:1e:dd:85 brd ff:ff:ff:ff:ff:ff $ ip -net test2 link show dev dummy2 6: dummy2: mtu 1500 qdisc noop state DOWN mode DEFAULT group default qlen 1000 link/ether 5a:3c:af:35:07:c3 brd ff:ff:ff:ff:ff:ff But the batman-adv code to walk through the various layers of virtual interfaces uses this assumption because dev_get_iflink handles it internally and doesn't return the actual netns of the iflink. And dev_get_iflink only documents the situation where ifindex == iflink for physical devices. But only checking for dev->netdev_ops->ndo_get_iflink is also not an option because ipoib_get_iflink implements it even when it sometimes returns an iflink != ifindex and sometimes iflink == ifindex. The caller must therefore make sure itself to check both netns' and iflink + ifindex for equality. Only when they are equal, an "physical" interface was detected which should stop the traversal. On the other hand, vxcan_get_iflink can also return 0 in case there was currently no valid peer. Fixes: 3d48811b27f5 ("batman-adv: prevent using any virtual device created on batman-adv as hard-interface") Fixes: 2b45bb6c3aad ("batman-adv: additional checks for virtual interfaces on top of WiFi") Reported-by: Sabrina Dubroca Signed-off-by: Sven Eckelmann --- net/batman-adv/hard-interface.c | 19 ++++++++++++++----- 1 file changed, 14 insertions(+), 5 deletions(-) diff --git a/net/batman-adv/hard-interface.c b/net/batman-adv/hard-interface.c index 8ed128bb..cdb6e542 100644 --- a/net/batman-adv/hard-interface.c +++ b/net/batman-adv/hard-interface.c @@ -157,13 +157,15 @@ static bool batadv_is_on_batman_iface(const struct net_device *net_dev) return true; iflink = dev_get_iflink(net_dev); - - /* no more parents..stop recursion */ - if (iflink == 0 || iflink == net_dev->ifindex) + if (iflink == 0) return false; parent_net = batadv_getlink_net(net_dev, net); + /* iflink to itself, most likely physical device */ + if (net == parent_net && iflink == net_dev->ifindex) + return false; + /* recurse over the parent device */ parent_dev = __dev_get_by_index((struct net *)parent_net, iflink); /* if we got a NULL parent_dev there is something broken.. */ @@ -223,8 +225,7 @@ static struct net_device *batadv_get_real_netdevice(struct net_device *netdev) return NULL; iflink = dev_get_iflink(netdev); - - if (netdev->ifindex == iflink) { + if (iflink == 0) { dev_hold(netdev); return netdev; } @@ -235,6 +236,14 @@ static struct net_device *batadv_get_real_netdevice(struct net_device *netdev) net = dev_net(hard_iface->soft_iface); real_net = batadv_getlink_net(netdev, net); + + /* iflink to itself, most likely physical device */ + if (net == real_net && netdev->ifindex == iflink) { + real_netdev = netdev; + dev_hold(real_netdev); + goto out; + } + real_netdev = dev_get_by_index(real_net, iflink); out: