1 files changed, 48 insertions, 59 deletions

diff --git a/net/wireless/reg.c b/net/wireless/reg.c
index fb40428a5946..b3ac0aace0e5 100644
--- a/net/wireless/reg.c
+++ b/net/wireless/reg.c
@@ -62,6 +62,16 @@ const struct ieee80211_regdomain *cfg80211_regdomain;
  */
 static const struct ieee80211_regdomain *country_ie_regdomain;
 
+/*
+ * Protects static reg.c components:
+ *     - cfg80211_world_regdom
+ *     - cfg80211_regdom
+ *     - country_ie_regdomain
+ *     - last_request
+ */
+DEFINE_MUTEX(reg_mutex);
+#define assert_reg_lock() WARN_ON(!mutex_is_locked(&reg_mutex))
+
 /* Used to queue up regulatory hints */
 static LIST_HEAD(reg_requests_list);
 static spinlock_t reg_requests_lock;
@@ -1293,7 +1303,7 @@ static void handle_channel_custom(struct wiphy *wiphy,
 	struct ieee80211_supported_band *sband;
 	struct ieee80211_channel *chan;
 
-	assert_cfg80211_lock();
+	assert_reg_lock();
 
 	sband = wiphy->bands[band];
 	BUG_ON(chan_idx >= sband->n_channels);
@@ -1342,14 +1352,14 @@ void wiphy_apply_custom_regulatory(struct wiphy *wiphy,
 	enum ieee80211_band band;
 	unsigned int bands_set = 0;
 
-	mutex_lock(&cfg80211_mutex);
+	mutex_lock(&reg_mutex);
 	for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
 		if (!wiphy->bands[band])
 			continue;
 		handle_band_custom(wiphy, band, regd);
 		bands_set++;
 	}
-	mutex_unlock(&cfg80211_mutex);
+	mutex_unlock(&reg_mutex);
 
 	/*
 	 * no point in calling this if it won't have any effect
@@ -1495,7 +1505,7 @@ static int ignore_request(struct wiphy *wiphy,
  * Returns zero if all went fine, %-EALREADY if a regulatory domain had
  * already been set or other standard error codes.
  *
- * Caller must hold &cfg80211_mutex
+ * Caller must hold &cfg80211_mutex and &reg_mutex
  */
 static int __regulatory_hint(struct wiphy *wiphy,
 			     struct regulatory_request *pending_request)
@@ -1570,6 +1580,7 @@ static void reg_process_hint(struct regulatory_request *reg_request)
 	BUG_ON(!reg_request->alpha2);
 
 	mutex_lock(&cfg80211_mutex);
+	mutex_lock(&reg_mutex);
 
 	if (wiphy_idx_valid(reg_request->wiphy_idx))
 		wiphy = wiphy_idx_to_wiphy(reg_request->wiphy_idx);
@@ -1585,6 +1596,7 @@ static void reg_process_hint(struct regulatory_request *reg_request)
 	if (r == -EALREADY && wiphy && wiphy->strict_regulatory)
 		wiphy_update_regulatory(wiphy, reg_request->initiator);
 out:
+	mutex_unlock(&reg_mutex);
 	mutex_unlock(&cfg80211_mutex);
 }
 
@@ -1613,6 +1625,10 @@ static void reg_process_pending_beacon_hints(void)
 	struct cfg80211_registered_device *rdev;
 	struct reg_beacon *pending_beacon, *tmp;
 
+	/*
+	 * No need to hold the reg_mutex here as we just touch wiphys
+	 * and do not read or access regulatory variables.
+	 */
 	mutex_lock(&cfg80211_mutex);
 
 	/* This goes through the _pending_ beacon list */
@@ -1734,12 +1750,13 @@ int regulatory_hint(struct wiphy *wiphy, const char *alpha2)
 }
 EXPORT_SYMBOL(regulatory_hint);
 
+/* Caller must hold reg_mutex */
 static bool reg_same_country_ie_hint(struct wiphy *wiphy,
 			u32 country_ie_checksum)
 {
 	struct wiphy *request_wiphy;
 
-	assert_cfg80211_lock();
+	assert_reg_lock();
 
 	if (unlikely(last_request->initiator !=
 	    NL80211_REGDOM_SET_BY_COUNTRY_IE))
@@ -1762,6 +1779,10 @@ static bool reg_same_country_ie_hint(struct wiphy *wiphy,
 	return false;
 }
 
+/*
+ * We hold wdev_lock() here so we cannot hold cfg80211_mutex() and
+ * therefore cannot iterate over the rdev list here.
+ */
 void regulatory_hint_11d(struct wiphy *wiphy,
 			u8 *country_ie,
 			u8 country_ie_len)
@@ -1772,12 +1793,10 @@ void regulatory_hint_11d(struct wiphy *wiphy,
 	enum environment_cap env = ENVIRON_ANY;
 	struct regulatory_request *request;
 
-	mutex_lock(&cfg80211_mutex);
+	mutex_lock(&reg_mutex);
 
-	if (unlikely(!last_request)) {
-		mutex_unlock(&cfg80211_mutex);
-		return;
-	}
+	if (unlikely(!last_request))
+		goto out;
 
 	/* IE len must be evenly divisible by 2 */
 	if (country_ie_len & 0x01)
@@ -1803,54 +1822,14 @@ void regulatory_hint_11d(struct wiphy *wiphy,
 		env = ENVIRON_OUTDOOR;
 
 	/*
-	 * We will run this for *every* beacon processed for the BSSID, so
-	 * we optimize an early check to exit out early if we don't have to
-	 * do anything
+	 * We will run this only upon a successful connection on cfg80211.
+	 * We leave conflict resolution to the workqueue, where can hold
+	 * cfg80211_mutex.
 	 */
 	if (likely(last_request->initiator ==
 	    NL80211_REGDOM_SET_BY_COUNTRY_IE &&
-	    wiphy_idx_valid(last_request->wiphy_idx))) {
-		struct cfg80211_registered_device *rdev_last_ie;
-
-		rdev_last_ie =
-			cfg80211_rdev_by_wiphy_idx(last_request->wiphy_idx);
-
-		/*
-		 * Lets keep this simple -- we trust the first AP
-		 * after we intersect with CRDA
-		 */
-		if (likely(&rdev_last_ie->wiphy == wiphy)) {
-			/*
-			 * Ignore IEs coming in on this wiphy with
-			 * the same alpha2 and environment cap
-			 */
-			if (likely(alpha2_equal(rdev_last_ie->country_ie_alpha2,
-				  alpha2) &&
-				  env == rdev_last_ie->env)) {
-				goto out;
-			}
-			/*
-			 * the wiphy moved on to another BSSID or the AP
-			 * was reconfigured. XXX: We need to deal with the
-			 * case where the user suspends and goes to goes
-			 * to another country, and then gets IEs from an
-			 * AP with different settings
-			 */
-			goto out;
-		} else {
-			/*
-			 * Ignore IEs coming in on two separate wiphys with
-			 * the same alpha2 and environment cap
-			 */
-			if (likely(alpha2_equal(rdev_last_ie->country_ie_alpha2,
-				  alpha2) &&
-				  env == rdev_last_ie->env)) {
-				goto out;
-			}
-			/* We could potentially intersect though */
-			goto out;
-		}
-	}
+	    wiphy_idx_valid(last_request->wiphy_idx)))
+		goto out;
 
 	rd = country_ie_2_rd(country_ie, country_ie_len, &checksum);
 	if (!rd)
@@ -1885,7 +1864,7 @@ void regulatory_hint_11d(struct wiphy *wiphy,
 	request->country_ie_checksum = checksum;
 	request->country_ie_env = env;
 
-	mutex_unlock(&cfg80211_mutex);
+	mutex_unlock(&reg_mutex);
 
 	queue_regulatory_request(request);
 
@@ -1894,9 +1873,8 @@ void regulatory_hint_11d(struct wiphy *wiphy,
 free_rd_out:
 	kfree(rd);
 out:
-	mutex_unlock(&cfg80211_mutex);
+	mutex_unlock(&reg_mutex);
 }
-EXPORT_SYMBOL(regulatory_hint_11d);
 
 static bool freq_is_chan_12_13_14(u16 freq)
 {
@@ -2227,10 +2205,13 @@ int set_regdom(const struct ieee80211_regdomain *rd)
 
 	assert_cfg80211_lock();
 
+	mutex_lock(&reg_mutex);
+
 	/* Note that this doesn't update the wiphys, this is done below */
 	r = __set_regdom(rd);
 	if (r) {
 		kfree(rd);
+		mutex_unlock(&reg_mutex);
 		return r;
 	}
 
@@ -2245,6 +2226,8 @@ int set_regdom(const struct ieee80211_regdomain *rd)
 
 	nl80211_send_reg_change_event(last_request);
 
+	mutex_unlock(&reg_mutex);
+
 	return r;
 }
 
@@ -2255,16 +2238,20 @@ void reg_device_remove(struct wiphy *wiphy)
 
 	assert_cfg80211_lock();
 
+	mutex_lock(&reg_mutex);
+
 	kfree(wiphy->regd);
 
 	if (last_request)
 		request_wiphy = wiphy_idx_to_wiphy(last_request->wiphy_idx);
 
 	if (!request_wiphy || request_wiphy != wiphy)
-		return;
+		goto out;
 
 	last_request->wiphy_idx = WIPHY_IDX_STALE;
 	last_request->country_ie_env = ENVIRON_ANY;
+out:
+	mutex_unlock(&reg_mutex);
 }
 
 int regulatory_init(void)
@@ -2325,6 +2312,7 @@ void regulatory_exit(void)
 	cancel_work_sync(&reg_work);
 
 	mutex_lock(&cfg80211_mutex);
+	mutex_lock(&reg_mutex);
 
 	reset_regdomains();
 
@@ -2363,5 +2351,6 @@ void regulatory_exit(void)
 	}
 	spin_unlock(&reg_requests_lock);
 
+	mutex_unlock(&reg_mutex);
 	mutex_unlock(&cfg80211_mutex);
 }