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 X-Spam-Level: X-Spam-Status: No, score=-18.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 51D54C433EF for ; Mon, 20 Sep 2021 20:46:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 30B3C61100 for ; Mon, 20 Sep 2021 20:46:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236352AbhITUsT (ORCPT ); Mon, 20 Sep 2021 16:48:19 -0400 Received: from gate2.alliedtelesis.co.nz ([202.36.163.20]:40601 "EHLO gate2.alliedtelesis.co.nz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231474AbhITUqO (ORCPT ); Mon, 20 Sep 2021 16:46:14 -0400 Received: from svr-chch-seg1.atlnz.lc (mmarshal3.atlnz.lc [10.32.18.43]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by gate2.alliedtelesis.co.nz (Postfix) with ESMTPS id 3FCCB806AC; Tue, 21 Sep 2021 08:44:43 +1200 (NZST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alliedtelesis.co.nz; s=mail181024; t=1632170683; bh=Cn+19qSMvfgrOTGheCboaarnn1DHBPEuHJWDY1D7Op8=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=Y4FtHIIpJl3KwVIy+BopoqYloLYg+M7m7ZIerKet2iatALeBCuE4P6oBX/dq5YJiu JsV5/MvOvO+yuHeVZMylnlgYFYTgNASHe7vYQHe2MoLzqxaCSDF3AwfL55QXuoUOx8 kXpvL7bZBAjefbsuQYeOSTrKeQH93nnZYYPZfjLKijOjUiUfXeiZTBHaJAvm+S3u3+ yY76eKmtm0VA0Q6i416hTrDO3dL7DdUz7FPBGJF9R8kDA2w20e2SyQrvGq5xWPghYR E7r96aRDUL4Y2tGo+spUgbqiJkNWozzGuQ3jVv2FpbVafJzKhhMLQ0n/Gi7LwZs53c 7Iqeo8XVeBVlw== Received: from pat.atlnz.lc (Not Verified[10.32.16.33]) by svr-chch-seg1.atlnz.lc with Trustwave SEG (v8,2,6,11305) id ; Tue, 21 Sep 2021 08:44:42 +1200 Received: from coled-dl.ws.atlnz.lc (coled-dl.ws.atlnz.lc [10.33.25.26]) by pat.atlnz.lc (Postfix) with ESMTP id DB4F513EEA3; Tue, 21 Sep 2021 08:44:42 +1200 (NZST) Received: by coled-dl.ws.atlnz.lc (Postfix, from userid 1801) id D5EF1242823; Tue, 21 Sep 2021 08:44:42 +1200 (NZST) From: Cole Dishington To: pablo@netfilter.org, kadlec@netfilter.org, fw@strlen.de, davem@davemloft.net, kuba@kernel.org, shuah@kernel.org Cc: linux-kernel@vger.kernel.org, netfilter-devel@vger.kernel.org, coreteam@netfilter.org, netdev@vger.kernel.org, Cole Dishington , Anthony Lineham , Scott Parlane , Blair Steven Subject: [PATCH net v6 1/2] net: netfilter: Limit the number of ftp helper port attempts Date: Tue, 21 Sep 2021 08:44:38 +1200 Message-Id: <20210920204439.13179-2-Cole.Dishington@alliedtelesis.co.nz> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20210920204439.13179-1-Cole.Dishington@alliedtelesis.co.nz> References: <20210920204439.13179-1-Cole.Dishington@alliedtelesis.co.nz> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-SEG-SpamProfiler-Analysis: v=2.3 cv=FtN7AFjq c=1 sm=1 tr=0 a=KLBiSEs5mFS1a/PbTCJxuA==:117 a=7QKq2e-ADPsA:10 a=v0C0h8vM-w728WOTjeQA:9 a=7Zwj6sZBwVKJAoWSPKxL6X1jA+E=:19 X-SEG-SpamProfiler-Score: 0 x-atlnz-ls: pat Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In preparation of fixing the port selection of ftp helper when using NF_NAT_RANGE_PROTO_SPECIFIED, limit the number of ftp helper port attempts to 128. Looping a large port range takes too long. Instead select a random offset within [ntohs(exp->saved_proto.tcp.port), 65535] and try 128 ports. Co-developed-by: Anthony Lineham Signed-off-by: Anthony Lineham Co-developed-by: Scott Parlane Signed-off-by: Scott Parlane Co-developed-by: Blair Steven Signed-off-by: Blair Steven Signed-off-by: Cole Dishington Acked-by: Florian Westphal --- Notes: Thanks for your time reviewing! Changes: - Add missing argument from nf_ct_helper_log. - Add Acked-by: Florian Westphal net/netfilter/nf_nat_ftp.c | 39 +++++++++++++++++++++++++------------- 1 file changed, 26 insertions(+), 13 deletions(-) diff --git a/net/netfilter/nf_nat_ftp.c b/net/netfilter/nf_nat_ftp.c index aace6768a64e..2da29e5d4309 100644 --- a/net/netfilter/nf_nat_ftp.c +++ b/net/netfilter/nf_nat_ftp.c @@ -72,8 +72,11 @@ static unsigned int nf_nat_ftp(struct sk_buff *skb, u_int16_t port; int dir =3D CTINFO2DIR(ctinfo); struct nf_conn *ct =3D exp->master; + unsigned int i, min, max, range_size; + static const unsigned int max_attempts =3D 128; char buffer[sizeof("|1||65535|") + INET6_ADDRSTRLEN]; unsigned int buflen; + int ret; =20 pr_debug("type %i, off %u len %u\n", type, matchoff, matchlen); =20 @@ -86,22 +89,32 @@ static unsigned int nf_nat_ftp(struct sk_buff *skb, * this one. */ exp->expectfn =3D nf_nat_follow_master; =20 - /* Try to get same port: if not, try to change it. */ - for (port =3D ntohs(exp->saved_proto.tcp.port); port !=3D 0; port++) { - int ret; - - exp->tuple.dst.u.tcp.port =3D htons(port); - ret =3D nf_ct_expect_related(exp, 0); - if (ret =3D=3D 0) - break; - else if (ret !=3D -EBUSY) { - port =3D 0; - break; + min =3D ntohs(exp->saved_proto.tcp.port); + max =3D 65535; + + /* Try to get same port */ + ret =3D nf_ct_expect_related(exp, 0); + + /* if same port is not in range or available, try to change it. */ + if (ret !=3D 0) { + range_size =3D max - min + 1; + if (range_size > max_attempts) + range_size =3D max_attempts; + + port =3D min + prandom_u32_max(max - min); + for (i =3D 0; i < range_size; i++) { + exp->tuple.dst.u.tcp.port =3D htons(port); + ret =3D nf_ct_expect_related(exp, 0); + if (ret !=3D -EBUSY) + break; + port++; + if (port > max) + port =3D min; } } =20 - if (port =3D=3D 0) { - nf_ct_helper_log(skb, ct, "all ports in use"); + if (ret !=3D 0) { + nf_ct_helper_log(skb, ct, "tried %u ports, all were in use", range_siz= e); return NF_DROP; } =20 --=20 2.33.0