[PATCH nft] src: set on flags to request multi-statement support

[Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>]

Old kernel reject requests for element with multiple statements because
userspace sets on the flags for multi-statements.

Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
---
 include/linux/netfilter/nf_tables.h | 3 +++
 src/evaluate.c                      | 8 ++++++++
 src/netlink_linearize.c             | 2 ++
 3 files changed, 13 insertions(+)

diff --git a/include/linux/netfilter/nf_tables.h b/include/linux/netfilter/nf_tables.h
index 0b5fd5d52bb6..4ecf457f7317 100644
--- a/include/linux/netfilter/nf_tables.h
+++ b/include/linux/netfilter/nf_tables.h
@@ -279,6 +279,7 @@ enum nft_rule_compat_attributes {
  * @NFT_SET_EVAL: set can be updated from the evaluation path
  * @NFT_SET_OBJECT: set contains stateful objects
  * @NFT_SET_CONCAT: set contains a concatenation
+ * @NFT_SET_EXPR: set contains expressions
  */
 enum nft_set_flags {
 	NFT_SET_ANONYMOUS		= 0x1,
@@ -289,6 +290,7 @@ enum nft_set_flags {
 	NFT_SET_EVAL			= 0x20,
 	NFT_SET_OBJECT			= 0x40,
 	NFT_SET_CONCAT			= 0x80,
+	NFT_SET_EXPR			= 0x100,
 };
 
 /**
@@ -686,6 +688,7 @@ enum nft_dynset_ops {
 
 enum nft_dynset_flags {
 	NFT_DYNSET_F_INV	= (1 << 0),
+	NFT_DYNSET_F_EXPR	= (1 << 1),
 };
 
 /**
diff --git a/src/evaluate.c b/src/evaluate.c
index ab9357fa2ede..38dbc33d7826 100644
--- a/src/evaluate.c
+++ b/src/evaluate.c
@@ -3671,7 +3671,9 @@ static int set_key_data_error(struct eval_ctx *ctx, const struct set *set,
 
 static int set_evaluate(struct eval_ctx *ctx, struct set *set)
 {
+	unsigned int num_stmts = 0;
 	struct table *table;
+	struct stmt *stmt;
 	const char *type;
 
 	table = table_lookup_global(ctx);
@@ -3732,6 +3734,12 @@ static int set_evaluate(struct eval_ctx *ctx, struct set *set)
 	if (set->timeout)
 		set->flags |= NFT_SET_TIMEOUT;
 
+	list_for_each_entry(stmt, &set->stmt_list, list)
+		num_stmts++;
+
+	if (num_stmts > 1)
+		set->flags |= NFT_SET_EXPR;
+
 	if (set_is_anonymous(set->flags))
 		return 0;
 
diff --git a/src/netlink_linearize.c b/src/netlink_linearize.c
index 09d0c61cfcc0..f1b3ff6940ea 100644
--- a/src/netlink_linearize.c
+++ b/src/netlink_linearize.c
@@ -1429,6 +1429,8 @@ static void netlink_gen_set_stmt(struct netlink_linearize_ctx *ctx,
 			nftnl_expr_add_expr(nle, NFTNL_EXPR_DYNSET_EXPRESSIONS,
 					    netlink_gen_stmt_stateful(this));
 		}
+		nftnl_expr_set_u32(nle, NFTNL_EXPR_DYNSET_FLAGS,
+				   NFT_DYNSET_F_EXPR);
 	}
 }
 
-- 
2.20.1