[PATCH 4.9 37/47] net: ieee802154: fix nl802154 add llsec key

[Greg Kroah-Hartman]

From: Alexander Aring <aahringo@xxxxxxxxxx>

commit 20d5fe2d7103f5c43ad11a3d6d259e9d61165c35 upstream.

This patch fixes a nullpointer dereference if NL802154_ATTR_SEC_KEY is
not set by the user. If this is the case nl802154 will return -EINVAL.

Reported-by: syzbot+ce4e062c2d51977ddc50@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Alexander Aring <aahringo@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20210221174321.14210-3-aahringo@xxxxxxxxxx
Signed-off-by: Stefan Schmidt <stefan@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 net/ieee802154/nl802154.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/net/ieee802154/nl802154.c
+++ b/net/ieee802154/nl802154.c
@@ -1577,7 +1577,8 @@ static int nl802154_add_llsec_key(struct
 	struct ieee802154_llsec_key_id id = { };
 	u32 commands[NL802154_CMD_FRAME_NR_IDS / 32] = { };
 
-	if (nla_parse_nested(attrs, NL802154_KEY_ATTR_MAX,
+	if (!info->attrs[NL802154_ATTR_SEC_KEY] ||
+	    nla_parse_nested(attrs, NL802154_KEY_ATTR_MAX,
 			     info->attrs[NL802154_ATTR_SEC_KEY],
 			     nl802154_key_policy))
 		return -EINVAL;