From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9A4E2C77B60 for ; Wed, 22 Mar 2023 21:53:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230025AbjCVVxT (ORCPT ); Wed, 22 Mar 2023 17:53:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58744 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230022AbjCVVxR (ORCPT ); Wed, 22 Mar 2023 17:53:17 -0400 Received: from mail.netfilter.org (mail.netfilter.org [217.70.188.207]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 5930118155 for ; Wed, 22 Mar 2023 14:53:10 -0700 (PDT) From: Pablo Neira Ayuso To: netfilter-devel@vger.kernel.org Subject: [PATCH nft,v2 4/8] evaluate: get length from statement instead of lhs expression Date: Wed, 22 Mar 2023 22:52:59 +0100 Message-Id: <20230322215303.239763-5-pablo@netfilter.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20230322215303.239763-1-pablo@netfilter.org> References: <20230322215303.239763-1-pablo@netfilter.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: netfilter-devel@vger.kernel.org Get length from statement, instead infering it from the expression that is used to set the value. In the particular case of {ct|meta} mark, this is 32 bits. Otherwise, bytecode generation is not correct: # nft -c --debug=netlink 'add rule ip6 x y ct mark set ip6 dscp << 2 | 0x10' [ payload load 2b @ network header + 0 => reg 1 ] [ bitwise reg 1 = ( reg 1 & 0x0000c00f ) ^ 0x00000000 ] [ bitwise reg 1 = ( reg 1 >> 0x00000006 ) ] [ byteorder reg 1 = ntoh(reg 1, 2, 1) ] [ bitwise reg 1 = ( reg 1 << 0x00000002 ) ] [ bitwise reg 1 = ( reg 1 & 0x00000fef ) ^ 0x00000010 ] <--- incorrect! [ ct set mark with reg 1 ] the previous bitwise shift already upgraded to 32-bits (not visible from the netlink debug output above). After this patch, the last | 0x10 uses 32-bits: [ bitwise reg 1 = ( reg 1 & 0xffffffef ) ^ 0x00000010 ] note that mask 0xffffffef is used instead of 0x00000fef. Signed-off-by: Pablo Neira Ayuso --- src/evaluate.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/src/evaluate.c b/src/evaluate.c index dfb1236e3b8a..613daa974971 100644 --- a/src/evaluate.c +++ b/src/evaluate.c @@ -1325,7 +1325,7 @@ static int expr_evaluate_bitwise(struct eval_ctx *ctx, struct expr **expr) op->dtype = left->dtype; op->byteorder = left->byteorder; - op->len = left->len; + op->len = ctx->ectx.len; if (expr_is_constant(left)) return constant_binop_simplify(ctx, expr); -- 2.30.2