Return-path: Received: from mail-wm0-f49.google.com ([74.125.82.49]:39499 "EHLO mail-wm0-f49.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751805AbeEHMek (ORCPT ); Tue, 8 May 2018 08:34:40 -0400 Received: by mail-wm0-f49.google.com with SMTP id f8-v6so21262277wmc.4 for ; Tue, 08 May 2018 05:34:39 -0700 (PDT) Subject: Re: [PATCH] nl80211: Reject disconnect commands except from conn_owner To: Johannes Berg , Andrew Zaborowski , Kalle Valo References: <20180428014732.4018-1-andrew.zaborowski@intel.com> <87in8b8ooy.fsf@purkki.adurom.net> <1525720752.22388.3.camel@sipsolutions.net> <5AF1959E.6020605@broadcom.com> <1525781970.14830.11.camel@sipsolutions.net> Cc: linux-wireless@vger.kernel.org From: Arend van Spriel Message-ID: <5AF1995D.3040204@broadcom.com> (sfid-20180508_143452_529504_B7923B28) Date: Tue, 8 May 2018 14:34:37 +0200 MIME-Version: 1.0 In-Reply-To: <1525781970.14830.11.camel@sipsolutions.net> Content-Type: text/plain; charset=utf-8; format=flowed Sender: linux-wireless-owner@vger.kernel.org List-ID: On 5/8/2018 2:19 PM, Johannes Berg wrote: > On Tue, 2018-05-08 at 14:18 +0200, Arend van Spriel wrote: >> On 5/7/2018 9:19 PM, Johannes Berg wrote: >>> On Sun, 2018-04-29 at 20:30 +0200, Andrew Zaborowski wrote: >>>> On 28 April 2018 at 15:07, Kalle Valo wrote: >>>>> Andrew Zaborowski writes: >>>>>> Reject NL80211_CMD_DISCONNECT, NL80211_CMD_DISASSOCIATE, >>>>>> NL80211_CMD_DEAUTHENTICATE and NL80211_CMD_ASSOCIATE commands >>>>>> from clients other than the connection owner set in the connect, >>>>>> authenticate or associate commands, if it was set. >>>>>> >>>>>> The main point of this check is to prevent chaos when two processes >>>>>> try to use nl80211 at the same time, it's not a security measure. >>>>>> The same thing should possibly be done for JOIN_IBSS/LEAVE_IBSS and >>>>>> START_AP/STOP_AP. >>>>> >>>>> s-o-b missing. >>>> >>>> True, thanks. Also I was going to send this as an RFC. >>>> >>> >>> Looks fine to me, please resend if you want it in :) >> >> Do we really want this? Is the referred chaos hypothetical or an actual >> issue. Nothing stops me from doing an 'ifconfig down' so why should 'iw >> disconnect' be any different. As far I can tell it does not affect my >> testing environment, but particularly in such use-cases I can expect >> issues adopting this change, which is also hypothetical of course ;-) > > Yeah, it's a good question. But it might help with inadvertent issues, > like starting wpa_s which immediately disconnects if it finds something > connected. If that fails, perhaps you have a better chance of noticing > the error? Sure. I guess we all have been there kicking of wpa_s and discovering there is already one running in the background. I am just a bit squeamish to change the behavior like this. Hmmmm. Is wpa_s already using SOCKET_OWNER. If so, I might create a patch to opt-out for that so people can knowingly choose chaos ;-) Regards, Arend