net: ieee802154: fix nl802154 del llsec devkey

stable inclusion
from stable-5.10.30
commit 0238c7b47f7714a707c13a6fb0642113cbaba2cd
bugzilla: 51791

--------------------------------

commit 27c74686 upstream.

This patch fixes a nullpointer dereference if NL802154_ATTR_SEC_DEVKEY is
not set by the user. If this is the case nl802154 will return -EINVAL.

Reported-by: syzbot+368672e0da240db53b5f@syzkaller.appspotmail.com
Signed-off-by: NAlexander Aring <aahringo@redhat.com>
Link: https://lore.kernel.org/r/20210221174321.14210-4-aahringo@redhat.comSigned-off-by: NStefan Schmidt <stefan@datenfreihafen.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NChen Jun <chenjun102@huawei.com>
Acked-by: N  Weilong Chen <chenweilong@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

net/ieee802154/nl802154.c

@@ -1916,7 +1916,8 @@ static int nl802154_del_llsec_devkey(struct sk_buff *skb, struct genl_info *info
 	struct ieee802154_llsec_device_key key;
 	__le64 extended_addr;
 
-	if (nla_parse_nested_deprecated(attrs, NL802154_DEVKEY_ATTR_MAX, info->attrs[NL802154_ATTR_SEC_DEVKEY], nl802154_devkey_policy, info->extack))
+	if (!info->attrs[NL802154_ATTR_SEC_DEVKEY] ||
+	    nla_parse_nested_deprecated(attrs, NL802154_DEVKEY_ATTR_MAX, info->attrs[NL802154_ATTR_SEC_DEVKEY], nl802154_devkey_policy, info->extack))
 		return -EINVAL;
 
 	if (!attrs[NL802154_DEVKEY_ATTR_EXTENDED_ADDR])