cfg80211: validate IBSS BSSID

The IBSS BSSID is never validated, so an
invalid one might end up being used. Fix
this by rejecting invalid configuration.

Reported-by: Marek Lindner <lindner_marek@yahoo.de>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 1108954..430b432 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -4527,8 +4527,12 @@
 
 	wiphy = &rdev->wiphy;
 
-	if (info->attrs[NL80211_ATTR_MAC])
+	if (info->attrs[NL80211_ATTR_MAC]) {
 		ibss.bssid = nla_data(info->attrs[NL80211_ATTR_MAC]);
+
+		if (!is_valid_ether_addr(ibss.bssid))
+			return -EINVAL;
+	}
 	ibss.ssid = nla_data(info->attrs[NL80211_ATTR_SSID]);
 	ibss.ssid_len = nla_len(info->attrs[NL80211_ATTR_SSID]);