[PATCH 4.4 31/38] net: ieee802154: fix nl802154 del llsec devkey

[Greg Kroah-Hartman]

From: Alexander Aring <aahringo@xxxxxxxxxx>

commit 27c746869e1a135dffc2f2a80715bb7aa00445b4 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@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Alexander Aring <aahringo@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20210221174321.14210-4-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
@@ -1908,7 +1908,8 @@ static int nl802154_del_llsec_devkey(str
 	struct ieee802154_llsec_device_key key;
 	__le64 extended_addr;
 
-	if (nla_parse_nested(attrs, NL802154_DEVKEY_ATTR_MAX,
+	if (!info->attrs[NL802154_ATTR_SEC_DEVKEY] ||
+	    nla_parse_nested(attrs, NL802154_DEVKEY_ATTR_MAX,
 			     info->attrs[NL802154_ATTR_SEC_DEVKEY],
 			     nl802154_devkey_policy))
 		return -EINVAL;