From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mx3.wp.pl ([212.77.101.7]:16079 "EHLO mx3.wp.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753657Ab3FGQmO convert rfc822-to-8bit (ORCPT ); Fri, 7 Jun 2013 12:42:14 -0400 Date: Fri, 7 Jun 2013 18:42:10 +0200 From: Jakub =?UTF-8?B?S2ljacWEc2tp?= To: Felix Fietkau Cc: linux-wireless@vger.kernel.org, Helmut Schaa , Johannes Berg , nietrywialneprzejscie@gmail.com Subject: Re: [RFC 4/5] mac80211: enforce address verification on monitors Message-ID: <20130607184210.200dbb52@north> (sfid-20130607_184217_839508_A51BFF6C) In-Reply-To: <51B1EDA8.10406@openwrt.org> References: <1370612179-24385-1-git-send-email-moorray3@wp.pl> <1370612179-24385-5-git-send-email-moorray3@wp.pl> <51B1E4F3.9020509@openwrt.org> <20130607160402.49ea16c3@north> <51B1EDA8.10406@openwrt.org> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-wireless-owner@vger.kernel.org List-ID: On Fri, 07 Jun 2013 16:26:48 +0200, Felix Fietkau wrote: >On 2013-06-07 4:04 PM, Jakub Kiciński wrote: >> On Fri, 07 Jun 2013 15:49:39 +0200, Felix Fietkau wrote: >>> On 2013-06-07 3:36 PM, Jakub Kicinski wrote: >>>> From: Jakub Kicinski >>>> >>>> Mac address of passive monitor have to treated >>>> the same as address any other interface because >>>> type of interface can be changed or monitor can >>>> be later put into active mode. >>> It can't. There's checks preventing that. I'd prefer to leave that part >>> of the code as it is, the MAC address for normal monitor interfaces >>> should be ignored completely. >> >> I must have misread the code regarding active monitors then. >> Main motivation behind this patch was the first part though >> - user can change type of interface and once ignored address >> of monitor now becomes address of AP, sta etc. > I'm pretty sure that switching from monitor to something else is also > not supported. Ok, let me explain what I mean to prevent by showing a command trace - running unpatched wireless-testing and patched iw [1]. # lsmod | grep mac8 # modprobe rt2800usb # iw dev wlan0 interface add wlan0-1 type managed # ip link 75: wlan0: mtu 1500 qdisc noop state DOWN qlen 1000 link/ether 00:4f:6a:06:57:90 brd ff:ff:ff:ff:ff:ff 76: wlan0-1: mtu 1500 qdisc noop state DOWN qlen 1000 link/ether 00:4f:6a:06:57:91 brd ff:ff:ff:ff:ff:ff Now I can start two hostapd on those interfaces and everything works just fine. # iw dev wlan0-1 set type monitor # ip link set dev wlan0-1 address 00:00:fa:22:7c:00 # iw dev wlan0-1 set type managed # ip link 75: wlan0: mtu 1500 qdisc mq state UP qlen 1000 link/ether 00:4f:6a:06:57:90 brd ff:ff:ff:ff:ff:ff 76: wlan0-1: mtu 1500 qdisc mq state UP qlen 1000 link/ether 00:00:fa:22:7c:00 brd ff:ff:ff:ff:ff:ff If I start hostapd on both interfaces now the one on wlan0-1 will not work correctly (hw won't ack frames). Also I think it's possible to change active flag on a monitor while it's down (check in net/mac80211/cfg.c:75 only applies to interfaces that are up): # iw dev wlan0 interface add wlan0-1 type monitor flags active # iw dev wlan0-1 set monitor none # iw dev wlan0-1 set monitor active # iw dev wlan0-1 set monitor none -- kuba [1] http://moorray.hopto.org/iw_active_monitors.patch