net: ieee802154: forbid monitor for add llsec seclevel

[ Upstream commit 9ec87e32

 ]

This patch forbids to add llsec seclevel for monitor interfaces which we
don't support yet. Otherwise we will access llsec mib which isn't
initialized for monitors.
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Link: https://lore.kernel.org/r/20210405003054.256017-14-aahringo@redhat.com

Signed-off-by: Stefan Schmidt <stefan@datenfreihafen.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

net/ieee802154/nl802154.c

@@ -2138,6 +2138,9 @@ static int nl802154_add_llsec_seclevel(struct sk_buff *skb,
 	struct wpan_dev *wpan_dev = dev->ieee802154_ptr;
 	struct ieee802154_llsec_seclevel sl;
 
+	if (wpan_dev->iftype == NL802154_IFTYPE_MONITOR)
+		return -EOPNOTSUPP;
+
 	if (llsec_parse_seclevel(info->attrs[NL802154_ATTR_SEC_LEVEL],
 				 &sl) < 0)
 		return -EINVAL;