diff --git a/include/net/netlink.h b/include/net/netlink.h
index b318b0a9f6c38d7520b96308b5d69e6db47f6529..318b1ded3833392a9b4ca8f6f997a9db8f70a1f1 100644
--- a/include/net/netlink.h
+++ b/include/net/netlink.h
@@ -181,6 +181,8 @@ enum {
 	NLA_S64,
 	NLA_BITFIELD32,
 	NLA_REJECT,
+	NLA_EXACT_LEN,
+	NLA_EXACT_LEN_WARN,
 	__NLA_TYPE_MAX,
 };
 
@@ -211,6 +213,10 @@ enum {
  *                         just like "All other"
  *    NLA_BITFIELD32       Unused
  *    NLA_REJECT           Unused
+ *    NLA_EXACT_LEN        Attribute must have exactly this length, otherwise
+ *                         it is rejected.
+ *    NLA_EXACT_LEN_WARN   Attribute should have exactly this length, a warning
+ *                         is logged if it is longer, shorter is rejected.
  *    All other            Minimum length of attribute payload
  *
  * Meaning of `validation_data' field:
@@ -236,6 +242,13 @@ struct nla_policy {
 	void            *validation_data;
 };
 
+#define NLA_POLICY_EXACT_LEN(_len)	{ .type = NLA_EXACT_LEN, .len = _len }
+#define NLA_POLICY_EXACT_LEN_WARN(_len)	{ .type = NLA_EXACT_LEN_WARN, \
+					  .len = _len }
+
+#define NLA_POLICY_ETH_ADDR		NLA_POLICY_EXACT_LEN(ETH_ALEN)
+#define NLA_POLICY_ETH_ADDR_COMPAT	NLA_POLICY_EXACT_LEN_WARN(ETH_ALEN)
+
 /**
  * struct nl_info - netlink source information
  * @nlh: Netlink message header of original request
diff --git a/lib/nlattr.c b/lib/nlattr.c
index 36d74b07915159d9ed153bcd0aeb65e4a8f07778..bb6fe5ed4ecf5682716d04181afc9a7c6a7f9b30 100644
--- a/lib/nlattr.c
+++ b/lib/nlattr.c
@@ -82,12 +82,18 @@ static int validate_nla(const struct nlattr *nla, int maxtype,
 
 	BUG_ON(pt->type > NLA_TYPE_MAX);
 
-	if (nla_attr_len[pt->type] && attrlen != nla_attr_len[pt->type]) {
+	if ((nla_attr_len[pt->type] && attrlen != nla_attr_len[pt->type]) ||
+	    (pt->type == NLA_EXACT_LEN_WARN && attrlen != pt->len)) {
 		pr_warn_ratelimited("netlink: '%s': attribute type %d has an invalid length.\n",
 				    current->comm, type);
 	}
 
 	switch (pt->type) {
+	case NLA_EXACT_LEN:
+		if (attrlen != pt->len)
+			return -ERANGE;
+		break;
+
 	case NLA_REJECT:
 		if (pt->validation_data && error_msg)
 			*error_msg = pt->validation_data;