evaluate: fix crash when handling concatenation without map

Fix a crash when map is not specified, e.g.

 nft add rule x y snat ip addr . port to 1.1.1.1 . 22

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

1 files changed, 3 insertions, 0 deletions

diff --git a/src/evaluate.c b/src/evaluate.c
index cad65cfb..8c227eb1 100644
--- a/src/evaluate.c
+++ b/src/evaluate.c
@@ -2924,6 +2924,9 @@ static int stmt_evaluate_nat_map(struct eval_ctx *ctx, struct stmt *stmt)
 	if (expr_evaluate(ctx, &stmt->nat.addr))
 		return -1;
 
+	if (stmt->nat.addr->etype != EXPR_MAP)
+		return 0;
+
 	data = stmt->nat.addr->mappings->set->data;
 	datatype_set(data, dtype);