netfilter: nf_tables: Utilize NLA_POLICY_NESTED_ARRAY

Mark attributes which are supposed to be arrays of nested attributes
with known content as such. Originally suggested for
NFTA_RULE_EXPRESSIONS only, but does apply to others as well.
Suggested-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: Florian Westphal <fw@strlen.de>

net/netfilter/nf_tables_api.c

@@ -3316,7 +3316,7 @@ static const struct nla_policy nft_rule_policy[NFTA_RULE_MAX + 1] = {
 	[NFTA_RULE_CHAIN]	= { .type = NLA_STRING,
 				    .len = NFT_CHAIN_MAXNAMELEN - 1 },
 	[NFTA_RULE_HANDLE]	= { .type = NLA_U64 },
-	[NFTA_RULE_EXPRESSIONS]	= { .type = NLA_NESTED },
+	[NFTA_RULE_EXPRESSIONS]	= NLA_POLICY_NESTED_ARRAY(nft_expr_policy),
 	[NFTA_RULE_COMPAT]	= { .type = NLA_NESTED },
 	[NFTA_RULE_POSITION]	= { .type = NLA_U64 },
 	[NFTA_RULE_USERDATA]	= { .type = NLA_BINARY,
@@ -4254,12 +4254,16 @@ static const struct nla_policy nft_set_policy[NFTA_SET_MAX + 1] = {
 	[NFTA_SET_OBJ_TYPE]		= { .type = NLA_U32 },
 	[NFTA_SET_HANDLE]		= { .type = NLA_U64 },
 	[NFTA_SET_EXPR]			= { .type = NLA_NESTED },
-	[NFTA_SET_EXPRESSIONS]		= { .type = NLA_NESTED },
+	[NFTA_SET_EXPRESSIONS]		= NLA_POLICY_NESTED_ARRAY(nft_expr_policy),
+};
+
+static const struct nla_policy nft_concat_policy[NFTA_SET_FIELD_MAX + 1] = {
+	[NFTA_SET_FIELD_LEN]	= { .type = NLA_U32 },
 };
 
 static const struct nla_policy nft_set_desc_policy[NFTA_SET_DESC_MAX + 1] = {
 	[NFTA_SET_DESC_SIZE]		= { .type = NLA_U32 },
-	[NFTA_SET_DESC_CONCAT]		= { .type = NLA_NESTED },
+	[NFTA_SET_DESC_CONCAT]		= NLA_POLICY_NESTED_ARRAY(nft_concat_policy),
 };
 
 static struct nft_set *nft_set_lookup(const struct nft_table *table,
@@ -4715,10 +4719,6 @@ static int nf_tables_getset(struct sk_buff *skb, const struct nfnl_info *info,
 	return err;
 }
 
-static const struct nla_policy nft_concat_policy[NFTA_SET_FIELD_MAX + 1] = {
-	[NFTA_SET_FIELD_LEN]	= { .type = NLA_U32 },
-};
-
 static int nft_set_desc_concat_parse(const struct nlattr *attr,
 				     struct nft_set_desc *desc)
 {
@@ -5500,7 +5500,7 @@ static const struct nla_policy nft_set_elem_policy[NFTA_SET_ELEM_MAX + 1] = {
 	[NFTA_SET_ELEM_OBJREF]		= { .type = NLA_STRING,
 					    .len = NFT_OBJ_MAXNAMELEN - 1 },
 	[NFTA_SET_ELEM_KEY_END]		= { .type = NLA_NESTED },
-	[NFTA_SET_ELEM_EXPRESSIONS]	= { .type = NLA_NESTED },
+	[NFTA_SET_ELEM_EXPRESSIONS]	= NLA_POLICY_NESTED_ARRAY(nft_expr_policy),
 };
 
 static const struct nla_policy nft_set_elem_list_policy[NFTA_SET_ELEM_LIST_MAX + 1] = {
@@ -5508,7 +5508,7 @@ static const struct nla_policy nft_set_elem_list_policy[NFTA_SET_ELEM_LIST_MAX +
 					    .len = NFT_TABLE_MAXNAMELEN - 1 },
 	[NFTA_SET_ELEM_LIST_SET]	= { .type = NLA_STRING,
 					    .len = NFT_SET_MAXNAMELEN - 1 },
-	[NFTA_SET_ELEM_LIST_ELEMENTS]	= { .type = NLA_NESTED },
+	[NFTA_SET_ELEM_LIST_ELEMENTS]	= NLA_POLICY_NESTED_ARRAY(nft_set_elem_policy),
 	[NFTA_SET_ELEM_LIST_SET_ID]	= { .type = NLA_U32 },
 };