netdev - Re: [PATCH] cfg80211: free the object allocated in wiphy_apply_custom

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <e549fbb09d7c618762996aca4242c2ae50f85a5c.camel@sipsolutions.net>
Date:   Fri, 23 Jul 2021 11:42:40 +0200
From:   Johannes Berg <johannes@...solutions.net>
To:     Dongliang Mu <mudongliangabcd@...il.com>
Cc:     Kalle Valo <kvalo@...eaurora.org>,
        "David S. Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>,
        Luca Coelho <luciano.coelho@...el.com>,
        Ilan Peer <ilan.peer@...el.com>,
        syzbot+1638e7c770eef6b6c0d0@...kaller.appspotmail.com,
        linux-wireless@...r.kernel.org,
        "open list:NETWORKING [GENERAL]" <netdev@...r.kernel.org>,
        linux-kernel <linux-kernel@...r.kernel.org>,
        Dan Carpenter <dan.carpenter@...cle.com>
Subject: Re: [PATCH] cfg80211: free the object allocated in
 wiphy_apply_custom_regulatory

Hi,

On Fri, 2021-07-23 at 17:30 +0800, Dongliang Mu wrote:
> if zhao in the thread is right, we don't need to add this free
> operation to wiphy_free().

Actually, no, that statement is not true.

All that zhao claimed was that the free happens correctly during
unregister (or later), and that is indeed true, since it happens from

ieee80211_unregister_hw()
 -> wiphy_unregister()
 -> wiphy_regulatory_deregister()

However, syzbot of course is also correct. Abstracting a bit and
ignoring mac80211, the problem is that here we assign it before
wiphy_register(), then wiphy_register() doesn't get called or fails, and
therefore we don't call wiphy_unregister(), only wiphy_free().

Hence the leak.

But you can also easily see from that description that it's not related
to hwsim - we should add a secondary round of cleanups in wiphy_free()
or even move the call to wiphy_regulatory_deregister() into
wiphy_free(), we need to look what else this does to see if we can move
it or not.

johannes