From patchwork Sun May 28 14:00:53 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jeremy Sowden X-Patchwork-Id: 1786848 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@legolas.ozlabs.org Authentication-Results: legolas.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org (client-ip=2620:137:e000::1:20; helo=out1.vger.email; envelope-from=netfilter-devel-owner@vger.kernel.org; receiver=) Authentication-Results: legolas.ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; secure) header.d=azazel.net header.i=@azazel.net header.a=rsa-sha256 header.s=20220717 header.b=rTed2Ag4; dkim-atps=neutral Received: from out1.vger.email (out1.vger.email [IPv6:2620:137:e000::1:20]) by legolas.ozlabs.org (Postfix) with ESMTP id 4QTgLq4vX3z20Pc for ; Mon, 29 May 2023 00:01:39 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229492AbjE1OBg (ORCPT ); Sun, 28 May 2023 10:01:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58328 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229510AbjE1OBe (ORCPT ); Sun, 28 May 2023 10:01:34 -0400 Received: from taras.nevrast.org (unknown [IPv6:2a05:d01c:431:aa03:b7e1:333d:ea2a:b14e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 91A9DBE for ; Sun, 28 May 2023 07:01:31 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=azazel.net; s=20220717; h=Content-Transfer-Encoding:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To:Content-Type:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=b9hQOEhXXcYfqfFFLTfwt5uzr9cPzLp69WgTS0CdMHA=; b=rTed2Ag4LUmC7R/Y32LrD95z3c qIpBochAs1VuD/gF75HQ4nOMSgcDxpirzrcOfvsnJklxdAyRCwc7HAjmYBODNwQ3U/9rvFFPbLxbH RoYiTLNoiXmbUnakunnP1OfGXUmTksPKkN34EtEh+oRxBLFwxSgoNhYQcLmo0C9p6Zi27sAArI1GG HZVyCSbfar9ZMxHI5vlfd3mZa+rdxjkDbphCboWD7rhH3V7BRZejVa3qEBnqFzlB/0qr37EcWOY9Z 7YFKRTA9sfjTRll+0io8KvsHt8LtBtcBgOAP7DbzxAYpkVRloSN8skwJ47i38KyhunmaVJ0mCsuV4 haldRDHg==; Received: from [2001:8b0:135f:bcd1:e0cb:4eff:fedf:e608] (helo=ulthar.dreamlands) by taras.nevrast.org with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1q3Gxe-008Xe1-9U; Sun, 28 May 2023 15:01:30 +0100 From: Jeremy Sowden To: Netfilter Devel Cc: Kevin Darbyshire-Bryant Subject: [PATCH nft v5 3/8] netlink_delinearize: add support for processing variable payload statement arguments Date: Sun, 28 May 2023 15:00:53 +0100 Message-Id: <20230528140058.1218669-4-jeremy@azazel.net> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230528140058.1218669-1-jeremy@azazel.net> References: <20230528140058.1218669-1-jeremy@azazel.net> MIME-Version: 1.0 X-SA-Exim-Connect-IP: 2001:8b0:135f:bcd1:e0cb:4eff:fedf:e608 X-SA-Exim-Mail-From: jeremy@azazel.net X-SA-Exim-Scanned: No (on taras.nevrast.org); SAEximRunCond expanded to false X-Spam-Status: No, score=-1.3 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RDNS_NONE,SPF_HELO_FAIL, SPF_PASS,T_SCC_BODY_TEXT_LINE autolearn=no autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: netfilter-devel@vger.kernel.org If a user uses a variable payload expression in a payload statement, the structure of the statement value is not handled by the existing statement postprocessing function, so we need to extend it. Signed-off-by: Jeremy Sowden --- src/netlink_delinearize.c | 86 ++++++++++++++++++++++++++++++++++++--- 1 file changed, 80 insertions(+), 6 deletions(-) diff --git a/src/netlink_delinearize.c b/src/netlink_delinearize.c index d729fb85a3ed..b36440e7c106 100644 --- a/src/netlink_delinearize.c +++ b/src/netlink_delinearize.c @@ -3112,7 +3112,7 @@ static void stmt_payload_binop_pp(struct rule_pp_ctx *ctx, struct expr *binop) } } -static bool stmt_payload_binop_postprocess_i(struct rule_pp_ctx *ctx) +static bool stmt_payload_binop_postprocess_i_a(struct rule_pp_ctx *ctx) { struct expr *expr, *binop, *payload, *value, *mask; struct stmt *stmt = ctx->stmt; @@ -3166,6 +3166,68 @@ static bool stmt_payload_binop_postprocess_i(struct rule_pp_ctx *ctx) return true; } +static bool stmt_payload_binop_postprocess_i_b(struct rule_pp_ctx *ctx) +{ + struct dl_proto_ctx *dl = dl_proto_ctx(ctx); + struct expr *expr, *payload, *mask, *xor; + struct stmt *stmt = ctx->stmt; + unsigned int shift; + mpz_t tmp, bitmask; + + expr = stmt->payload.val; + + if (expr->op != OP_XOR) + return false; + + if (expr->left->etype != EXPR_BINOP) + return false; + + if (expr->left->op != OP_AND) + return false; + + if (expr->right->etype == EXPR_UNARY) { + /* + * If the payload value was originally in a different byte-order + * from the payload expression, there will be a byte-order + * conversion to remove. + */ + xor = expr_get(expr->right->arg); + expr_free(expr->right); + expr->right = xor; + } else + xor = expr->right; + + mask = expr->left->right; + payload = expr->left->left; + + mpz_init(tmp); + mpz_set(tmp, mask->value); + + mpz_init_bitmask(bitmask, payload->len); + mpz_xor(bitmask, bitmask, mask->value); + mpz_set(mask->value, bitmask); + mpz_clear(bitmask); + + if (payload_expr_trim(payload, mask, &dl->pctx, &shift)) + payload_match_postprocess(ctx, expr->left, payload); + + if (!payload_is_known(payload)) { + mpz_set(mask->value, tmp); + } else { + if (shift) { + expr->right = expr_get(xor->left); + expr_free(xor); + } + expr_free(stmt->payload.expr); + stmt->payload.expr = expr_get(payload); + stmt->payload.val = expr_get(expr->right); + expr_free(expr); + } + + mpz_clear(tmp); + return true; +} + static bool stmt_payload_binop_postprocess_ii(struct rule_pp_ctx *ctx) { struct expr *expr, *payload, *value; @@ -3233,21 +3295,30 @@ static bool stmt_payload_binop_postprocess_ii(struct rule_pp_ctx *ctx) * and a mask to clear the real payload offset/length. * * So check if we have one of the following binops: - * I) + * + * Ia) * binop (|) * binop(&) value/set * payload value(mask) * - * This is the normal case, the | RHS is the value the user wants - * to set, the & RHS is the mask value that discards bits we need + * This is the normal constant case, the | RHS is the value the user + * wants to set, the & RHS is the mask value that discards bits we need * to clear but retains everything unrelated to the set operation. * + * Ib) + * binop (^) + * binop(&) value/set + * payload value(mask) + * + * The user wants to set a variable payload argument. The ^ RHS is the + * variable expression. The mask is as above. + * * IIa) * binop (&) * payload mask * * User specified a zero set value -- netlink bitwise decoding - * discarded the redundant "| 0" part. This is identical to I), + * discarded the redundant "| 0" part. This is identical to Ia), * we can just set value to 0 after we inferred the real payload size. * * IIb) @@ -3270,7 +3341,10 @@ static void stmt_payload_binop_postprocess(struct rule_pp_ctx *ctx) switch (expr->left->etype) { case EXPR_BINOP: /* I? */ - if (stmt_payload_binop_postprocess_i(ctx)) + if (stmt_payload_binop_postprocess_i_a(ctx)) + return; + + if (stmt_payload_binop_postprocess_i_b(ctx)) return; break;