[PATCH] net: ieee802154: fix a null pointer in nl802154_trigger_scan

[Dongliang Mu]

There is a null pointer dereference if NL802154_ATTR_SCAN_TYPE is
not set by the user.

Fix this by adding a null pointer check.

Reported-and-tested-by: syzbot+bd85b31816913a32e473@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Dongliang Mu <dzm91@xxxxxxxxxxx>
---
 net/ieee802154/nl802154.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/net/ieee802154/nl802154.c b/net/ieee802154/nl802154.c
index 2215f576ee37..1cf00cffd63f 100644
--- a/net/ieee802154/nl802154.c
+++ b/net/ieee802154/nl802154.c
@@ -1412,7 +1412,8 @@ static int nl802154_trigger_scan(struct sk_buff *skb, struct genl_info *info)
 		return -EOPNOTSUPP;
 	}
 
-	if (!nla_get_u8(info->attrs[NL802154_ATTR_SCAN_TYPE])) {
+	if (!info->attrs[NL802154_ATTR_SCAN_TYPE] ||
+	    !nla_get_u8(info->attrs[NL802154_ATTR_SCAN_TYPE])) {
 		NL_SET_ERR_MSG(info->extack, "Malformed request, missing scan type");
 		return -EINVAL;
 	}
-- 
2.34.1