[PATCH nft] evaluate: stmt_nat: set reference must point to a map

[Florian Westphal <fw@strlen.de>]

nat_concat_map() requires a datamap, else we crash:
set->data is dereferenced.

Also update expr_evaluate_map() so that EXPR_SET_REF is checked there
too.

Signed-off-by: Florian Westphal <fw@strlen.de>
---
 src/evaluate.c                                         |  9 +++++++++
 .../bogons/nft-f/nat_stmt_with_set_instead_of_map      | 10 ++++++++++
 2 files changed, 19 insertions(+)
 create mode 100644 tests/shell/testcases/bogons/nft-f/nat_stmt_with_set_instead_of_map

diff --git a/src/evaluate.c b/src/evaluate.c
index 1b3e8097454d..da382912ea71 100644
--- a/src/evaluate.c
+++ b/src/evaluate.c
@@ -2041,6 +2041,9 @@ static int expr_evaluate_map(struct eval_ctx *ctx, struct expr **expr)
 		break;
 	case EXPR_SET_REF:
 		/* symbol has been already evaluated to set reference */
+		if (!set_is_map(mappings->set->flags))
+			return expr_error(ctx->msgs, map->mappings,
+					  "Expression is not a map");
 		break;
 	default:
 		return expr_binary_error(ctx->msgs, map->mappings, map->map,
@@ -3969,6 +3972,12 @@ static bool nat_concat_map(struct eval_ctx *ctx, struct stmt *stmt)
 		if (expr_evaluate(ctx, &stmt->nat.addr->mappings))
 			return false;
 
+		if (!set_is_datamap(stmt->nat.addr->mappings->set->flags)) {
+			expr_error(ctx->msgs, stmt->nat.addr->mappings,
+					  "Expression is not a map");
+			return false;
+		}
+
 		if (stmt->nat.addr->mappings->set->data->etype == EXPR_CONCAT ||
 		    stmt->nat.addr->mappings->set->data->dtype->subtypes) {
 			stmt->nat.type_flags |= STMT_NAT_F_CONCAT;
diff --git a/tests/shell/testcases/bogons/nft-f/nat_stmt_with_set_instead_of_map b/tests/shell/testcases/bogons/nft-f/nat_stmt_with_set_instead_of_map
new file mode 100644
index 000000000000..b1302278cc9b
--- /dev/null
+++ b/tests/shell/testcases/bogons/nft-f/nat_stmt_with_set_instead_of_map
@@ -0,0 +1,10 @@
+table inet x {
+        set y {
+                type ipv4_addr
+                elements = { 2.2.2.2, 3.3.3.3 }
+        }
+
+        chain y {
+                snat ip to ip saddr map @y
+        }
+}
-- 
2.41.0