cfg80211: fix locking

Over time, a lot of locking issues have crept into
the smarts of cfg80211, so e.g. scan completion can
race against a new scan, IBSS join can race against
leaving an IBSS, etc.

Introduce a new per-interface lock that protects
most of the per-interface data that we need to keep
track of, and sprinkle assertions about that lock
everywhere. Some things now need to be offloaded to
work structs so that we don't require being able to
sleep in functions the drivers call. The exception
to that are the MLME callbacks (rx_auth etc.) that
currently only mac80211 calls because it was easier
to do that there instead of in cfg80211, and future
drivers implementing those calls will, if they ever
exist, probably need to use a similar scheme like
mac80211 anyway...

In order to be able to handle _deauth and _disassoc
properly, introduce a cookie passed to it that will
determine locking requirements.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 106 insertions, 27 deletions

diff --git a/net/wireless/ibss.c b/net/wireless/ibss.c
index a5330c5..99ef936 100644
--- a/net/wireless/ibss.c
+++ b/net/wireless/ibss.c
@@ -10,7 +10,7 @@
 #include "nl80211.h"
 
 
-void cfg80211_ibss_joined(struct net_device *dev, const u8 *bssid, gfp_t gfp)
+void __cfg80211_ibss_joined(struct net_device *dev, const u8 *bssid)
 {
 	struct wireless_dev *wdev = dev->ieee80211_ptr;
 	struct cfg80211_bss *bss;
@@ -39,22 +39,45 @@ void cfg80211_ibss_joined(struct net_device *dev, const u8 *bssid, gfp_t gfp)
 	cfg80211_hold_bss(bss_from_pub(bss));
 	wdev->current_bss = bss_from_pub(bss);
 
-	nl80211_send_ibss_bssid(wiphy_to_dev(wdev->wiphy), dev, bssid, gfp);
+	nl80211_send_ibss_bssid(wiphy_to_dev(wdev->wiphy), dev, bssid,
+				GFP_KERNEL);
 #ifdef CONFIG_WIRELESS_EXT
 	memset(&wrqu, 0, sizeof(wrqu));
 	memcpy(wrqu.ap_addr.sa_data, bssid, ETH_ALEN);
 	wireless_send_event(dev, SIOCGIWAP, &wrqu, NULL);
 #endif
 }
+
+void cfg80211_ibss_joined(struct net_device *dev, const u8 *bssid, gfp_t gfp)
+{
+	struct wireless_dev *wdev = dev->ieee80211_ptr;
+	struct cfg80211_registered_device *rdev = wiphy_to_dev(wdev->wiphy);
+	struct cfg80211_event *ev;
+	unsigned long flags;
+
+	ev = kzalloc(sizeof(*ev), gfp);
+	if (!ev)
+		return;
+
+	ev->type = EVENT_IBSS_JOINED;
+	memcpy(ev->cr.bssid, bssid, ETH_ALEN);
+
+	spin_lock_irqsave(&wdev->event_lock, flags);
+	list_add_tail(&ev->list, &wdev->event_list);
+	spin_unlock_irqrestore(&wdev->event_lock, flags);
+	schedule_work(&rdev->event_work);
+}
 EXPORT_SYMBOL(cfg80211_ibss_joined);
 
-int cfg80211_join_ibss(struct cfg80211_registered_device *rdev,
-		       struct net_device *dev,
-		       struct cfg80211_ibss_params *params)
+int __cfg80211_join_ibss(struct cfg80211_registered_device *rdev,
+			 struct net_device *dev,
+			 struct cfg80211_ibss_params *params)
 {
 	struct wireless_dev *wdev = dev->ieee80211_ptr;
 	int err;
 
+	ASSERT_WDEV_LOCK(wdev);
+
 	if (wdev->ssid_len)
 		return -EALREADY;
 
@@ -72,10 +95,26 @@ int cfg80211_join_ibss(struct cfg80211_registered_device *rdev,
 	return 0;
 }
 
-void cfg80211_clear_ibss(struct net_device *dev, bool nowext)
+int cfg80211_join_ibss(struct cfg80211_registered_device *rdev,
+		       struct net_device *dev,
+		       struct cfg80211_ibss_params *params)
+{
+	struct wireless_dev *wdev = dev->ieee80211_ptr;
+	int err;
+
+	wdev_lock(wdev);
+	err = __cfg80211_join_ibss(rdev, dev, params);
+	wdev_unlock(wdev);
+
+	return err;
+}
+
+static void __cfg80211_clear_ibss(struct net_device *dev, bool nowext)
 {
 	struct wireless_dev *wdev = dev->ieee80211_ptr;
 
+	ASSERT_WDEV_LOCK(wdev);
+
 	if (wdev->current_bss) {
 		cfg80211_unhold_bss(wdev->current_bss);
 		cfg80211_put_bss(&wdev->current_bss->pub);
@@ -89,12 +128,23 @@ void cfg80211_clear_ibss(struct net_device *dev, bool nowext)
 #endif
 }
 
-int cfg80211_leave_ibss(struct cfg80211_registered_device *rdev,
-			struct net_device *dev, bool nowext)
+void cfg80211_clear_ibss(struct net_device *dev, bool nowext)
+{
+	struct wireless_dev *wdev = dev->ieee80211_ptr;
+
+	wdev_lock(wdev);
+	__cfg80211_clear_ibss(dev, nowext);
+	wdev_unlock(wdev);
+}
+
+static int __cfg80211_leave_ibss(struct cfg80211_registered_device *rdev,
+				 struct net_device *dev, bool nowext)
 {
 	struct wireless_dev *wdev = dev->ieee80211_ptr;
 	int err;
 
+	ASSERT_WDEV_LOCK(wdev);
+
 	if (!wdev->ssid_len)
 		return -ENOLINK;
 
@@ -103,11 +153,24 @@ int cfg80211_leave_ibss(struct cfg80211_registered_device *rdev,
 	if (err)
 		return err;
 
-	cfg80211_clear_ibss(dev, nowext);
+	__cfg80211_clear_ibss(dev, nowext);
 
 	return 0;
 }
 
+int cfg80211_leave_ibss(struct cfg80211_registered_device *rdev,
+			struct net_device *dev, bool nowext)
+{
+	struct wireless_dev *wdev = dev->ieee80211_ptr;
+	int err;
+
+	wdev_lock(wdev);
+	err = __cfg80211_leave_ibss(rdev, dev, nowext);
+	wdev_unlock(wdev);
+
+	return err;
+}
+
 #ifdef CONFIG_WIRELESS_EXT
 static int cfg80211_ibss_wext_join(struct cfg80211_registered_device *rdev,
 				   struct wireless_dev *wdev)
@@ -184,12 +247,15 @@ int cfg80211_ibss_wext_siwfreq(struct net_device *dev,
 	if (wdev->wext.ibss.channel == chan)
 		return 0;
 
-	if (wdev->ssid_len) {
-		err = cfg80211_leave_ibss(wiphy_to_dev(wdev->wiphy),
-					  dev, true);
-		if (err)
-			return err;
-	}
+	wdev_lock(wdev);
+	err = 0;
+	if (wdev->ssid_len)
+		err = __cfg80211_leave_ibss(wiphy_to_dev(wdev->wiphy),
+					    dev, true);
+	wdev_unlock(wdev);
+
+	if (err)
+		return err;
 
 	if (chan) {
 		wdev->wext.ibss.channel = chan;
@@ -215,10 +281,12 @@ int cfg80211_ibss_wext_giwfreq(struct net_device *dev,
 	if (WARN_ON(wdev->iftype != NL80211_IFTYPE_ADHOC))
 		return -EINVAL;
 
+	wdev_lock(wdev);
 	if (wdev->current_bss)
 		chan = wdev->current_bss->pub.channel;
 	else if (wdev->wext.ibss.channel)
 		chan = wdev->wext.ibss.channel;
+	wdev_unlock(wdev);
 
 	if (chan) {
 		freq->m = chan->center_freq;
@@ -247,12 +315,15 @@ int cfg80211_ibss_wext_siwessid(struct net_device *dev,
 	if (!wiphy_to_dev(wdev->wiphy)->ops->join_ibss)
 		return -EOPNOTSUPP;
 
-	if (wdev->ssid_len) {
-		err = cfg80211_leave_ibss(wiphy_to_dev(wdev->wiphy),
-					  dev, true);
-		if (err)
-			return err;
-	}
+	wdev_lock(wdev);
+	err = 0;
+	if (wdev->ssid_len)
+		err = __cfg80211_leave_ibss(wiphy_to_dev(wdev->wiphy),
+					    dev, true);
+	wdev_unlock(wdev);
+
+	if (err)
+		return err;
 
 	/* iwconfig uses nul termination in SSID.. */
 	if (len > 0 && ssid[len - 1] == '\0')
@@ -279,6 +350,7 @@ int cfg80211_ibss_wext_giwessid(struct net_device *dev,
 
 	data->flags = 0;
 
+	wdev_lock(wdev);
 	if (wdev->ssid_len) {
 		data->flags = 1;
 		data->length = wdev->ssid_len;
@@ -288,6 +360,7 @@ int cfg80211_ibss_wext_giwessid(struct net_device *dev,
 		data->length = wdev->wext.ibss.ssid_len;
 		memcpy(ssid, wdev->wext.ibss.ssid, data->length);
 	}
+	wdev_unlock(wdev);
 
 	return 0;
 }
@@ -325,12 +398,15 @@ int cfg80211_ibss_wext_siwap(struct net_device *dev,
 	    compare_ether_addr(bssid, wdev->wext.ibss.bssid) == 0)
 		return 0;
 
-	if (wdev->ssid_len) {
-		err = cfg80211_leave_ibss(wiphy_to_dev(wdev->wiphy),
-					  dev, true);
-		if (err)
-			return err;
-	}
+	wdev_lock(wdev);
+	err = 0;
+	if (wdev->ssid_len)
+		err = __cfg80211_leave_ibss(wiphy_to_dev(wdev->wiphy),
+					    dev, true);
+	wdev_unlock(wdev);
+
+	if (err)
+		return err;
 
 	if (bssid) {
 		memcpy(wdev->wext.bssid, bssid, ETH_ALEN);
@@ -355,10 +431,13 @@ int cfg80211_ibss_wext_giwap(struct net_device *dev,
 
 	ap_addr->sa_family = ARPHRD_ETHER;
 
+	wdev_lock(wdev);
 	if (wdev->current_bss)
 		memcpy(ap_addr->sa_data, wdev->current_bss->pub.bssid, ETH_ALEN);
 	else
 		memcpy(ap_addr->sa_data, wdev->wext.ibss.bssid, ETH_ALEN);
+	wdev_unlock(wdev);
+
 	return 0;
 }
 /* temporary symbol - mark GPL - in the future the handler won't be */