netlink: fix nat stmt linearization/parsing

Fix invalid register use when parsing NAT statements and handle range expressions
during postprocessing. When linearizing, allocate all registers for both proto and
address expressions at once to avoid double use.

Signed-off-by: Patrick McHardy <kaber@trash.net>

1 files changed, 24 insertions, 24 deletions

diff --git a/src/netlink_linearize.c b/src/netlink_linearize.c
index f3ff7d14..a3841fb9 100644
--- a/src/netlink_linearize.c
+++ b/src/netlink_linearize.c
@@ -500,53 +500,53 @@ static void netlink_gen_nat_stmt(struct netlink_linearize_ctx *ctx,
 	struct nfnl_nft_expr *nle;
 	enum nft_registers amin_reg, amax_reg;
 	enum nft_registers pmin_reg, pmax_reg;
+	int registers = 0;
 
 	nle = alloc_nft_expr(nfnl_nft_nat_init);
 	nfnl_nft_nat_set_type(nle, stmt->nat.type);
 
 	if (stmt->nat.addr) {
-		switch (stmt->nat.addr->ops->type) {
-		default:
-			amin_reg = amax_reg = get_register(ctx);
-			netlink_gen_expr(ctx, stmt->nat.addr, amin_reg);
-			nfnl_nft_nat_set_sreg_addr_min(nle, amin_reg);
-			release_register(ctx);
-			break;
-		case EXPR_RANGE:
-			amin_reg = get_register(ctx);
+		amin_reg = get_register(ctx);
+		registers++;
+
+		if (stmt->nat.addr->ops->type == EXPR_RANGE) {
 			amax_reg = get_register(ctx);
+			registers++;
+
 			netlink_gen_expr(ctx, stmt->nat.addr->left, amin_reg);
 			netlink_gen_expr(ctx, stmt->nat.addr->right, amax_reg);
 			nfnl_nft_nat_set_sreg_addr_min(nle, amin_reg);
 			nfnl_nft_nat_set_sreg_addr_max(nle, amax_reg);
-			release_register(ctx);
-			release_register(ctx);
-			break;
+		} else {
+			netlink_gen_expr(ctx, stmt->nat.addr, amin_reg);
+			nfnl_nft_nat_set_sreg_addr_min(nle, amin_reg);
 		}
 
 	}
 
 	if (stmt->nat.proto) {
-		switch (stmt->nat.proto->ops->type) {
-		default:
-			pmin_reg = pmax_reg = get_register(ctx);
-			netlink_gen_expr(ctx, stmt->nat.proto, pmin_reg);
-			nfnl_nft_nat_set_sreg_proto_min(nle, pmin_reg);
-			release_register(ctx);
-			break;
-		case EXPR_RANGE:
-			pmin_reg = get_register(ctx);
+		pmin_reg = get_register(ctx);
+		registers++;
+
+		if (stmt->nat.proto->ops->type == EXPR_RANGE) {
 			pmax_reg = get_register(ctx);
+			registers++;
+
 			netlink_gen_expr(ctx, stmt->nat.proto->left, pmin_reg);
 			netlink_gen_expr(ctx, stmt->nat.proto->right, pmax_reg);
 			nfnl_nft_nat_set_sreg_proto_min(nle, pmin_reg);
 			nfnl_nft_nat_set_sreg_proto_max(nle, pmax_reg);
-			release_register(ctx);
-			release_register(ctx);
-			break;
+		} else {
+			netlink_gen_expr(ctx, stmt->nat.proto, pmin_reg);
+			nfnl_nft_nat_set_sreg_proto_min(nle, pmin_reg);
 		}
 	}
 
+	while (registers > 0) {
+		release_register(ctx);
+		registers--;
+	}
+
 	nfnl_nft_rule_add_expr(ctx->nlr, nle);
 }