nl80211: fix per-station group key get/del and memory leak

commit 0fa7b391 upstream.

In case userspace attempts to obtain key information for or delete a
unicast key, this is currently erroneously rejected unless the driver
sets the WIPHY_FLAG_IBSS_RSN flag. Apparently enough drivers do so it
was never noticed.

Fix that, and while at it fix a potential memory leak: the error path
in the get_key() function was placed after allocating a message but
didn't free it - move it to a better place. Luckily admin permissions
are needed to call this operation.

Fixes: e31b8213 ("cfg80211/mac80211: allow per-station GTKs")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>

net/wireless/nl80211.c

@@ -2784,6 +2784,9 @@ static int nl80211_get_key(struct sk_buff *skb, struct genl_info *info)
 	if (!rdev->ops->get_key)
 		return -EOPNOTSUPP;
 
+	if (!pairwise && mac_addr && !(rdev->wiphy.flags & WIPHY_FLAG_IBSS_RSN))
+		return -ENOENT;
+
 	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 	if (!msg)
 		return -ENOMEM;
@@ -2803,10 +2806,6 @@ static int nl80211_get_key(struct sk_buff *skb, struct genl_info *info)
 	    nla_put(msg, NL80211_ATTR_MAC, ETH_ALEN, mac_addr))
 		goto nla_put_failure;
 
-	if (pairwise && mac_addr &&
-	    !(rdev->wiphy.flags & WIPHY_FLAG_IBSS_RSN))
-		return -ENOENT;
-
 	err = rdev_get_key(rdev, dev, key_idx, pairwise, mac_addr, &cookie,
 			   get_key_callback);
 
@@ -2977,7 +2976,7 @@ static int nl80211_del_key(struct sk_buff *skb, struct genl_info *info)
 	wdev_lock(dev->ieee80211_ptr);
 	err = nl80211_key_allowed(dev->ieee80211_ptr);
 
-	if (key.type == NL80211_KEYTYPE_PAIRWISE && mac_addr &&
+	if (key.type == NL80211_KEYTYPE_GROUP && mac_addr &&
 	    !(rdev->wiphy.flags & WIPHY_FLAG_IBSS_RSN))
 		err = -ENOENT;