Subject: [PATCH net-next v2 6/6] ethtool: report missing header via ext_ack in the default handler

From: Jakub Kicinski <[email-masked]>
Date: Wed, 24 Aug 2022 19:41:22 -0700

The actual presence check for the header is in
ethnl_parse_header_dev_get() but it's a few layers in,
and already has a ton of arguments so let's just pick
the low handing fruit and check for missing header in
the default request handler.

Signed-off-by: Jakub Kicinski <[email-masked]>
---
CC: [email-masked]
---
 net/ethtool/netlink.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/net/ethtool/netlink.c b/net/ethtool/netlink.c
index e26079e11835..0ccb177aaf04 100644
--- a/net/ethtool/netlink.c
+++ b/net/ethtool/netlink.c
@@ -361,6 +361,9 @@ static int ethnl_default_doit(struct sk_buff *skb, struct genl_info *info)
 	ops = ethnl_default_requests[cmd];
 	if (WARN_ONCE(!ops, "cmd %u has no ethnl_request_ops\n", cmd))
 		return -EOPNOTSUPP;
+	if (GENL_REQ_ATTR_CHECK(info, ops->hdr_attr))
+		return -EINVAL;
+
 	req_info = kzalloc(ops->req_info_size, GFP_KERNEL);
 	if (!req_info)
 		return -ENOMEM;
-- 
2.37.2