diff --git a/include/linux/netlink.h b/include/linux/netlink.h
index 205fa7b1f07ad..4090524c3462f 100644
--- a/include/linux/netlink.h
+++ b/include/linux/netlink.h
@@ -119,6 +119,15 @@ static inline void nl_set_extack_cookie_u64(struct netlink_ext_ack *extack,
 	extack->cookie_len = sizeof(__cookie);
 }
 
+static inline void nl_set_extack_cookie_u32(struct netlink_ext_ack *extack,
+					    u32 cookie)
+{
+	u32 __cookie = cookie;
+
+	memcpy(extack->cookie, &__cookie, sizeof(__cookie));
+	extack->cookie_len = sizeof(__cookie);
+}
+
 void netlink_kernel_release(struct sock *sk);
 int __netlink_change_ngroups(struct sock *sk, unsigned int groups);
 int netlink_change_ngroups(struct sock *sk, unsigned int groups);
diff --git a/net/ethtool/netlink.c b/net/ethtool/netlink.c
index 180c194fab076..fc9e0b8068898 100644
--- a/net/ethtool/netlink.c
+++ b/net/ethtool/netlink.c
@@ -40,6 +40,7 @@ int ethnl_parse_header(struct ethnl_req_info *req_info,
 	struct nlattr *tb[ETHTOOL_A_HEADER_MAX + 1];
 	const struct nlattr *devname_attr;
 	struct net_device *dev = NULL;
+	u32 flags = 0;
 	int ret;
 
 	if (!header) {
@@ -50,8 +51,17 @@ int ethnl_parse_header(struct ethnl_req_info *req_info,
 			       ethnl_header_policy, extack);
 	if (ret < 0)
 		return ret;
-	devname_attr = tb[ETHTOOL_A_HEADER_DEV_NAME];
+	if (tb[ETHTOOL_A_HEADER_FLAGS]) {
+		flags = nla_get_u32(tb[ETHTOOL_A_HEADER_FLAGS]);
+		if (flags & ~ETHTOOL_FLAG_ALL) {
+			NL_SET_ERR_MSG_ATTR(extack, tb[ETHTOOL_A_HEADER_FLAGS],
+					    "unrecognized request flags");
+			nl_set_extack_cookie_u32(extack, ETHTOOL_FLAG_ALL);
+			return -EOPNOTSUPP;
+		}
+	}
 
+	devname_attr = tb[ETHTOOL_A_HEADER_DEV_NAME];
 	if (tb[ETHTOOL_A_HEADER_DEV_INDEX]) {
 		u32 ifindex = nla_get_u32(tb[ETHTOOL_A_HEADER_DEV_INDEX]);
 
@@ -90,9 +100,7 @@ int ethnl_parse_header(struct ethnl_req_info *req_info,
 	}
 
 	req_info->dev = dev;
-	if (tb[ETHTOOL_A_HEADER_FLAGS])
-		req_info->flags = nla_get_u32(tb[ETHTOOL_A_HEADER_FLAGS]);
-
+	req_info->flags = flags;
 	return 0;
 }
 
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index 5313f1cec1706..2f234791b879f 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -2392,19 +2392,14 @@ void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err,
 	if (nlk_has_extack && extack && extack->_msg)
 		tlvlen += nla_total_size(strlen(extack->_msg) + 1);
 
-	if (err) {
-		if (!(nlk->flags & NETLINK_F_CAP_ACK))
-			payload += nlmsg_len(nlh);
-		else
-			flags |= NLM_F_CAPPED;
-		if (nlk_has_extack && extack && extack->bad_attr)
-			tlvlen += nla_total_size(sizeof(u32));
-	} else {
+	if (err && !(nlk->flags & NETLINK_F_CAP_ACK))
+		payload += nlmsg_len(nlh);
+	else
 		flags |= NLM_F_CAPPED;
-
-		if (nlk_has_extack && extack && extack->cookie_len)
-			tlvlen += nla_total_size(extack->cookie_len);
-	}
+	if (err && nlk_has_extack && extack && extack->bad_attr)
+		tlvlen += nla_total_size(sizeof(u32));
+	if (nlk_has_extack && extack && extack->cookie_len)
+		tlvlen += nla_total_size(extack->cookie_len);
 
 	if (tlvlen)
 		flags |= NLM_F_ACK_TLVS;
@@ -2427,20 +2422,16 @@ void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err,
 			WARN_ON(nla_put_string(skb, NLMSGERR_ATTR_MSG,
 					       extack->_msg));
 		}
-		if (err) {
-			if (extack->bad_attr &&
-			    !WARN_ON((u8 *)extack->bad_attr < in_skb->data ||
-				     (u8 *)extack->bad_attr >= in_skb->data +
-							       in_skb->len))
-				WARN_ON(nla_put_u32(skb, NLMSGERR_ATTR_OFFS,
-						    (u8 *)extack->bad_attr -
-						    (u8 *)nlh));
-		} else {
-			if (extack->cookie_len)
-				WARN_ON(nla_put(skb, NLMSGERR_ATTR_COOKIE,
-						extack->cookie_len,
-						extack->cookie));
-		}
+		if (err && extack->bad_attr &&
+		    !WARN_ON((u8 *)extack->bad_attr < in_skb->data ||
+			     (u8 *)extack->bad_attr >= in_skb->data +
+						       in_skb->len))
+			WARN_ON(nla_put_u32(skb, NLMSGERR_ATTR_OFFS,
+					    (u8 *)extack->bad_attr -
+					    (u8 *)nlh));
+		if (extack->cookie_len)
+			WARN_ON(nla_put(skb, NLMSGERR_ATTR_COOKIE,
+					extack->cookie_len, extack->cookie));
 	}
 
 	nlmsg_end(skb, rep);