linux-kernel - [245/264] mac80211: disable powersave for broken APs

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Date:	Wed, 09 Nov 2011 13:34:52 -0800
From:	Greg KH <gregkh@...e.de>
To:	linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:	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: [245/264] mac80211: disable powersave for broken APs

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

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

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

commit 05cb91085760ca378f28fc274fbf77fc4fd9886c upstream.

Only AID values 1-2007 are valid, but some APs have been
found to send random bogus values, in the reported case an
AP that was sending the AID field value 0xffff, an AID of
0x3fff (16383).

There isn't much we can do but disable powersave since
there's no way it can work properly in this case.

Reported-by: Bill C Riemers <briemers@...hat.com>
Signed-off-by: Johannes Berg <johannes.berg@...el.com>
Signed-off-by: John W. Linville <linville@...driver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...e.de>

---
 net/mac80211/ieee80211_i.h |    1 +
 net/mac80211/mlme.c        |   18 ++++++++++++++++--
 2 files changed, 17 insertions(+), 2 deletions(-)

--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -390,6 +390,7 @@ struct ieee80211_if_managed {
 
 	unsigned long timers_running; /* used for quiesce/restart */
 	bool powersave; /* powersave requested for this iface */
+	bool broken_ap; /* AP is broken -- turn off powersave */
 	enum ieee80211_smps_mode req_smps, /* requested smps mode */
 				 ap_smps, /* smps mode AP thinks we're in */
 				 driver_smps_mode; /* smps mode request */
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -613,6 +613,9 @@ static bool ieee80211_powersave_allowed(
 	if (!mgd->powersave)
 		return false;
 
+	if (mgd->broken_ap)
+		return false;
+
 	if (!mgd->associated)
 		return false;
 
@@ -1467,10 +1470,21 @@ static bool ieee80211_assoc_success(stru
 	capab_info = le16_to_cpu(mgmt->u.assoc_resp.capab_info);
 
 	if ((aid & (BIT(15) | BIT(14))) != (BIT(15) | BIT(14)))
-		printk(KERN_DEBUG "%s: invalid aid value %d; bits 15:14 not "
-		       "set\n", sdata->name, aid);
+		printk(KERN_DEBUG
+		       "%s: invalid AID value 0x%x; bits 15:14 not set\n",
+		       sdata->name, aid);
 	aid &= ~(BIT(15) | BIT(14));
 
+	ifmgd->broken_ap = false;
+
+	if (aid == 0 || aid > IEEE80211_MAX_AID) {
+		printk(KERN_DEBUG
+		       "%s: invalid AID value %d (out of range), turn off PS\n",
+		       sdata->name, aid);
+		aid = 0;
+		ifmgd->broken_ap = true;
+	}
+
 	pos = mgmt->u.assoc_resp.variable;
 	ieee802_11_parse_elems(pos, len - (pos - (u8 *) mgmt), &elems);
 


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