nftables/0013-netlink_delinearize-postprocess-binary-ands-in-conca.patch

From 29f041b93d7fc4e23c62c2e2e3cbbeaafa83b4ef Mon Sep 17 00:00:00 2001
From: Phil Sutter <psutter@redhat.com>
Date: Thu, 9 Feb 2023 10:27:57 +0100
Subject: [PATCH] netlink_delinearize: postprocess binary ands in
 concatenations

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2094887
Upstream Status: nftables commit 89688c947efc3

commit 89688c947efc36d25c58c85650414fa3a491732e
Author: Florian Westphal <fw@strlen.de>
Date:   Tue Jun 14 21:56:48 2022 +0200

    netlink_delinearize: postprocess binary ands in concatenations

    Input:
    update ether saddr . vlan id timeout 5s @macset
    ether saddr . vlan id @macset

    Before this patch, gets rendered as:
    update @macset { @ll,48,48 . @ll,112,16 & 0xfff timeout 5s }
    @ll,48,48 . @ll,112,16 & 0xfff @macset

    After this, listing will show:
    update @macset { @ll,48,48 . vlan id timeout 5s }
    @ll,48,48 . vlan id @macset

    The @ll, ... is due to vlan description replacing the ethernet one,
    so payload decode fails to take the concatenation apart (the ethernet
    header payload info is matched vs. vlan template).

    This will be adjusted by a followup patch.

    Signed-off-by: Florian Westphal <fw@strlen.de>

Signed-off-by: Phil Sutter <psutter@redhat.com>
---
 include/netlink.h         |  6 ++++++
 src/netlink_delinearize.c | 45 ++++++++++++++++++++++++++++++++++-----
 2 files changed, 46 insertions(+), 5 deletions(-)

diff --git a/include/netlink.h b/include/netlink.h
index e8e0f68..71c888f 100644
--- a/include/netlink.h
+++ b/include/netlink.h
@@ -42,10 +42,16 @@ struct netlink_parse_ctx {
 	struct netlink_ctx	*nlctx;
 };
 
+
+#define RULE_PP_IN_CONCATENATION	(1 << 0)
+
+#define RULE_PP_REMOVE_OP_AND		(RULE_PP_IN_CONCATENATION)
+
 struct rule_pp_ctx {
 	struct proto_ctx	pctx;
 	struct payload_dep_ctx	pdctx;
 	struct stmt		*stmt;
+	unsigned int		flags;
 };
 
 extern const struct input_descriptor indesc_netlink;
diff --git a/src/netlink_delinearize.c b/src/netlink_delinearize.c
index 2f13990..cba419d 100644
--- a/src/netlink_delinearize.c
+++ b/src/netlink_delinearize.c
@@ -2259,12 +2259,13 @@ static void binop_adjust(const struct expr *binop, struct expr *right,
 	}
 }
 
-static void binop_postprocess(struct rule_pp_ctx *ctx, struct expr *expr,
-			      struct expr **expr_binop)
+static void __binop_postprocess(struct rule_pp_ctx *ctx,
+				struct expr *expr,
+				struct expr *left,
+				struct expr *mask,
+				struct expr **expr_binop)
 {
 	struct expr *binop = *expr_binop;
-	struct expr *left = binop->left;
-	struct expr *mask = binop->right;
 	unsigned int shift;
 
 	assert(binop->etype == EXPR_BINOP);
@@ -2300,15 +2301,26 @@ static void binop_postprocess(struct rule_pp_ctx *ctx, struct expr *expr,
 
 		assert(binop->left == left);
 		*expr_binop = expr_get(left);
-		expr_free(binop);
 
 		if (left->etype == EXPR_PAYLOAD)
 			payload_match_postprocess(ctx, expr, left);
 		else if (left->etype == EXPR_EXTHDR && right)
 			expr_set_type(right, left->dtype, left->byteorder);
+
+		expr_free(binop);
 	}
 }
 
+static void binop_postprocess(struct rule_pp_ctx *ctx, struct expr *expr,
+			      struct expr **expr_binop)
+{
+	struct expr *binop = *expr_binop;
+	struct expr *left = binop->left;
+	struct expr *mask = binop->right;
+
+	__binop_postprocess(ctx, expr, left, mask, expr_binop);
+}
+
 static void map_binop_postprocess(struct rule_pp_ctx *ctx, struct expr *expr)
 {
 	struct expr *binop = expr->map;
@@ -2541,6 +2553,7 @@ static void expr_postprocess(struct rule_pp_ctx *ctx, struct expr **exprp)
 		LIST_HEAD(tmp);
 		struct expr *n;
 
+		ctx->flags |= RULE_PP_IN_CONCATENATION;
 		list_for_each_entry_safe(i, n, &expr->expressions, list) {
 			if (type) {
 				dtype = concat_subtype_lookup(type, --off);
@@ -2552,6 +2565,7 @@ static void expr_postprocess(struct rule_pp_ctx *ctx, struct expr **exprp)
 
 			ntype = concat_subtype_add(ntype, i->dtype->type);
 		}
+		ctx->flags &= ~RULE_PP_IN_CONCATENATION;
 		list_splice(&tmp, &expr->expressions);
 		datatype_set(expr, concat_type_alloc(ntype));
 		break;
@@ -2568,6 +2582,27 @@ static void expr_postprocess(struct rule_pp_ctx *ctx, struct expr **exprp)
 			expr_set_type(expr->right, &integer_type,
 				      BYTEORDER_HOST_ENDIAN);
 			break;
+		case OP_AND:
+			expr_set_type(expr->right, expr->left->dtype,
+				      expr->left->byteorder);
+
+			/* Do not process OP_AND in ordinary rule context.
+			 *
+			 * Removal needs to be performed as part of the relational
+			 * operation because the RHS constant might need to be adjusted
+			 * (shifted).
+			 *
+			 * This is different in set element context or concatenations:
+			 * There is no relational operation (eq, neq and so on), thus
+			 * it needs to be processed right away.
+			 */
+			if ((ctx->flags & RULE_PP_REMOVE_OP_AND) &&
+			    expr->left->etype == EXPR_PAYLOAD &&
+			    expr->right->etype == EXPR_VALUE) {
+				__binop_postprocess(ctx, expr, expr->left, expr->right, exprp);
+				return;
+			}
+			break;
 		default:
 			expr_set_type(expr->right, expr->left->dtype,
 				      expr->left->byteorder);
-- 
2.39.1