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mac80211: fix rx monitor filter refcounters

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This patch fixes an refcounting bug. Previously it
was possible to corrupt the per-device recv. filter
and monitor management counters when:
	iw dev wlanX set monitor [new flags]
was issued on an active monitor interface.

Acked-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Christian Lamparter <chunkeey@googlemail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
This commit is contained in:
Christian Lamparter
2010-10-02 13:17:07 +02:00
committed by John W. Linville
parent 5a254ffe3f
commit 85416a4fa1
3 changed files with 54 additions and 24 deletions
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32
net/mac80211/cfg.c
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@@ -68,8 +68,36 @@ static int ieee80211_change_iface(struct wiphy *wiphy,
params && params->use_4addr >= 0)
sdata->u.mgd.use_4addr = params->use_4addr;
if (sdata->vif.type == NL80211_IFTYPE_MONITOR && flags)
sdata->u.mntr_flags = *flags;
if (sdata->vif.type == NL80211_IFTYPE_MONITOR && flags) {
struct ieee80211_local *local = sdata->local;
if (ieee80211_sdata_running(sdata)) {
/*
* Prohibit MONITOR_FLAG_COOK_FRAMES to be
* changed while the interface is up.
* Else we would need to add a lot of cruft
* to update everything:
* cooked_mntrs, monitor and all fif_* counters
* reconfigure hardware
*/
if ((*flags & MONITOR_FLAG_COOK_FRAMES) !=
(sdata->u.mntr_flags & MONITOR_FLAG_COOK_FRAMES))
return -EBUSY;
ieee80211_adjust_monitor_flags(sdata, -1);
sdata->u.mntr_flags = *flags;
ieee80211_adjust_monitor_flags(sdata, 1);
ieee80211_configure_filter(local);
} else {
/*
* Because the interface is down, ieee80211_do_stop
* and ieee80211_do_open take care of "everything"
* mentioned in the comment above.
*/
sdata->u.mntr_flags = *flags;
}
}
return 0;
}