linux-kernel - [142/200] mac80211: fix deauth before assoc

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Message-Id: <20100701174258.400595778@clark.site>
Date:	Thu, 01 Jul 2010 10:43:52 -0700
From:	Greg KH <gregkh@...e.de>
To:	linux-kernel@...r.kernel.org, stable@...nel.org
Cc:	stable-review@...nel.org, torvalds@...ux-foundation.org,
	akpm@...ux-foundation.org, alan@...rguk.ukuu.org.uk,
	Johannes Berg <johannes.berg@...el.com>,
	"John W. Linville" <linville@...driver.com>
Subject: [142/200] mac80211: fix deauth before assoc

2.6.34-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Johannes Berg <johannes.berg@...el.com>

commit b054b747a694927879c94dd11af54d04346aed7d upstream.

When we receive a deauthentication frame before
having successfully associated, we neither print
a message nor abort assocation. The former makes
it hard to debug, while the latter later causes
a warning in cfg80211 when, as will typically be
the case, association timed out.

This warning was reported by many, e.g. in
https://bugzilla.kernel.org/show_bug.cgi?id=15981,
but I couldn't initially pinpoint it. I verified
the fix by hacking hostapd to send a deauth frame
instead of an association response.

Signed-off-by: Johannes Berg <johannes.berg@...el.com>
Tested-by: Miles Lane <miles.lane@...il.com>
Signed-off-by: John W. Linville <linville@...driver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...e.de>

---
 net/mac80211/mlme.c |   40 ++++++++++++++++++++++++++++++++++++++--
 1 file changed, 38 insertions(+), 2 deletions(-)

--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -1530,9 +1530,45 @@ static void ieee80211_sta_rx_queued_mgmt
 	mutex_unlock(&ifmgd->mtx);
 
 	if (skb->len >= 24 + 2 /* mgmt + deauth reason */ &&
-	    (fc & IEEE80211_FCTL_STYPE) == IEEE80211_STYPE_DEAUTH)
-		cfg80211_send_deauth(sdata->dev, (u8 *)mgmt, skb->len);
+	    (fc & IEEE80211_FCTL_STYPE) == IEEE80211_STYPE_DEAUTH) {
+		struct ieee80211_local *local = sdata->local;
+		struct ieee80211_work *wk;
+
+		mutex_lock(&local->work_mtx);
+		list_for_each_entry(wk, &local->work_list, list) {
+			if (wk->sdata != sdata)
+				continue;
+
+			if (wk->type != IEEE80211_WORK_ASSOC)
+				continue;
+
+			if (memcmp(mgmt->bssid, wk->filter_ta, ETH_ALEN))
+				continue;
+			if (memcmp(mgmt->sa, wk->filter_ta, ETH_ALEN))
+				continue;
 
+			/*
+			 * Printing the message only here means we can't
+			 * spuriously print it, but it also means that it
+			 * won't be printed when the frame comes in before
+			 * we even tried to associate or in similar cases.
+			 *
+			 * Ultimately, I suspect cfg80211 should print the
+			 * messages instead.
+			 */
+			printk(KERN_DEBUG
+			       "%s: deauthenticated from %pM (Reason: %u)\n",
+			       sdata->name, mgmt->bssid,
+			       le16_to_cpu(mgmt->u.deauth.reason_code));
+
+			list_del_rcu(&wk->list);
+			free_work(wk);
+			break;
+		}
+		mutex_unlock(&local->work_mtx);
+
+		cfg80211_send_deauth(sdata->dev, (u8 *)mgmt, skb->len);
+	}
  out:
 	kfree_skb(skb);
 }


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