Subject: Re: Management frame protection and packet injection from hostapd
From: Johannes Berg <johannes@sipsolutions.net>
To: Jouni Malinen <j@w1.fi>
Cc: linux-wireless@vger.kernel.org
In-Reply-To: <20080617073227.GA4974@jm.kir.nu>
References: <20080616143308.GB18479@jm.kir.nu>
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	 <1213634684.3803.43.camel@johannes.berg>
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Date: Tue, 17 Jun 2008 10:50:38 +0200
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> I did.. I added another set of functions for default management key and
> did not remember to call the removal function from
> ieee80211_free_keys(). However, adding that call did not change
> anything.

Ok.

> It looks like we end up trying to remove the netdev directory in debugfs
> before removing the default key symlinks. Consequently, debugfs_remove()
> fails since there is still a file in the directory. This is what happens
> when removing the monitor interface:
>=20
> cfg.c: ieee80211_del_iface() ->
> iface.c: ieee80211_if_remove() ->
> iface.c: __ieee80211_if_del() ->
> debugfs_netdev.c: ieee80211_debugfs_remove_netdev()
>     [too early; symlink still there]
> unregister_netdevice(dev) -> [dev->uninit]
> iface.c: ieee80211_if_reinit() ->
> key.c: ieee80211_free_keys() ->
> debugfs_key.c: ieee80211_debugfs_key_remove_default()
>=20
>=20
> Any idea how to fix this?=20

Hmm, no, no idea at all. To be honest, I don't fully understand
interface lifetime rules and I think many of those functions are
probably misnamed. I.e. why is the _reinit function assigned to the
->uninit callback? Much of that either comes from the original
Devicescape code or what Jiri did to it, and I never bothered to clean
it up.

> Why is ieee80211_debugfs_remove_netdev() call
> in __ieee80211_if_del()?=20

I don't really know. Probably because that's where Jiri had the sysfs
code I converted to debugfs ;)

> Could it be moved into ieee80211_if_reinit(),
> so that it would happen only after the ieee80211_free_keys() call?=20

That's well possible, I guess you'd have to try.

> Since
> ieee80211_if_reinit() is called from other places, too, it might be
> cleaner to define a new dev->uninit function that is a wrapper for call
> to ieee80211_if_reinit() followed by call to
> ieee80211_debugfs_remove_netdev().. However, since ieee80211_if_reinit()
> calls ieee80211_if_sdata_deinit(), it might be necessary to call
> ieee80211_debugfs_remove_netdev() before this call (or from it?); I did
> not yet look into details of what would be the required order for these.

I really don't know either. If you feel motivated to clean up the
interface handling I'd appreciate it.

johannes

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