From patchwork Thu Oct 15 16:39:27 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Pablo Neira Ayuso X-Patchwork-Id: 11839745 X-Patchwork-Delegate: kuba@kernel.org 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=-12.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 A6DF9C433E7 for ; Thu, 15 Oct 2020 16:39:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 54DA822255 for ; Thu, 15 Oct 2020 16:39:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389881AbgJOQjk (ORCPT ); Thu, 15 Oct 2020 12:39:40 -0400 Received: from correo.us.es ([193.147.175.20]:52652 "EHLO mail.us.es" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388946AbgJOQjj (ORCPT ); Thu, 15 Oct 2020 12:39:39 -0400 Received: from antivirus1-rhel7.int (unknown [192.168.2.11]) by mail.us.es (Postfix) with ESMTP id 9657FE4B86 for ; Thu, 15 Oct 2020 18:39:37 +0200 (CEST) Received: from antivirus1-rhel7.int (localhost [127.0.0.1]) by antivirus1-rhel7.int (Postfix) with ESMTP id 883C0DA73F for ; Thu, 15 Oct 2020 18:39:37 +0200 (CEST) Received: by antivirus1-rhel7.int (Postfix, from userid 99) id 7DBF5DA72F; Thu, 15 Oct 2020 18:39:37 +0200 (CEST) Received: from antivirus1-rhel7.int (localhost [127.0.0.1]) by antivirus1-rhel7.int (Postfix) with ESMTP id 623DDDA73D; Thu, 15 Oct 2020 18:39:35 +0200 (CEST) Received: from 192.168.1.97 (192.168.1.97) by antivirus1-rhel7.int (F-Secure/fsigk_smtp/550/antivirus1-rhel7.int); Thu, 15 Oct 2020 18:39:35 +0200 (CEST) X-Virus-Status: clean(F-Secure/fsigk_smtp/550/antivirus1-rhel7.int) Received: from localhost.localdomain (unknown [90.77.255.23]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: pneira@us.es) by entrada.int (Postfix) with ESMTPSA id 3121542EF4E0; Thu, 15 Oct 2020 18:39:35 +0200 (CEST) X-SMTPAUTHUS: auth mail.us.es From: Pablo Neira Ayuso To: netfilter-devel@vger.kernel.org Cc: davem@davemloft.net, netdev@vger.kernel.org, kuba@kernel.org Subject: [PATCH net-next] netfilter: nftables: allow re-computing sctp CRC-32C in 'payload' statements Date: Thu, 15 Oct 2020 18:39:27 +0200 Message-Id: <20201015163927.28730-1-pablo@netfilter.org> X-Mailer: git-send-email 2.20.1 MIME-Version: 1.0 X-Virus-Scanned: ClamAV using ClamSMTP Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org From: Davide Caratti nftables payload statements are used to mangle SCTP headers, but they can only replace the Internet Checksum. As a consequence, nftables rules that mangle sport/dport/vtag in SCTP headers potentially generate packets that are discarded by the receiver, unless the CRC-32C is "offloaded" (e.g the rule mangles a skb having 'ip_summed' equal to 'CHECKSUM_PARTIAL'. Fix this extending uAPI definitions and L4 checksum update function, in a way that userspace programs (e.g. nft) can instruct the kernel to compute CRC-32C in SCTP headers. Also ensure that LIBCRC32C is built if NF_TABLES is 'y' or 'm' in the kernel build configuration. Signed-off-by: Davide Caratti Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso --- @Jakub: This is my last pending item in nf-next I think, I'm not planning to send a pull request for a single patch, so please directly apply this one to net-next. Thank you. include/uapi/linux/netfilter/nf_tables.h | 2 ++ net/netfilter/Kconfig | 1 + net/netfilter/nft_payload.c | 28 ++++++++++++++++++++++++ 3 files changed, 31 insertions(+) diff --git a/include/uapi/linux/netfilter/nf_tables.h b/include/uapi/linux/netfilter/nf_tables.h index 352ee51707a1..98272cb5f617 100644 --- a/include/uapi/linux/netfilter/nf_tables.h +++ b/include/uapi/linux/netfilter/nf_tables.h @@ -749,10 +749,12 @@ enum nft_payload_bases { * * @NFT_PAYLOAD_CSUM_NONE: no checksumming * @NFT_PAYLOAD_CSUM_INET: internet checksum (RFC 791) + * @NFT_PAYLOAD_CSUM_SCTP: CRC-32c, for use in SCTP header (RFC 3309) */ enum nft_payload_csum_types { NFT_PAYLOAD_CSUM_NONE, NFT_PAYLOAD_CSUM_INET, + NFT_PAYLOAD_CSUM_SCTP, }; enum nft_payload_csum_flags { diff --git a/net/netfilter/Kconfig b/net/netfilter/Kconfig index 25313c29d799..52370211e46b 100644 --- a/net/netfilter/Kconfig +++ b/net/netfilter/Kconfig @@ -441,6 +441,7 @@ endif # NF_CONNTRACK config NF_TABLES select NETFILTER_NETLINK + select LIBCRC32C tristate "Netfilter nf_tables support" help nftables is the new packet classification framework that intends to diff --git a/net/netfilter/nft_payload.c b/net/netfilter/nft_payload.c index 7a2e59638499..dcd3c7b8a367 100644 --- a/net/netfilter/nft_payload.c +++ b/net/netfilter/nft_payload.c @@ -22,6 +22,7 @@ #include #include #include +#include static bool nft_payload_rebuild_vlan_hdr(const struct sk_buff *skb, int mac_off, struct vlan_ethhdr *veth) @@ -484,6 +485,19 @@ static int nft_payload_l4csum_offset(const struct nft_pktinfo *pkt, return 0; } +static int nft_payload_csum_sctp(struct sk_buff *skb, int offset) +{ + struct sctphdr *sh; + + if (skb_ensure_writable(skb, offset + sizeof(*sh))) + return -1; + + sh = (struct sctphdr *)(skb->data + offset); + sh->checksum = sctp_compute_cksum(skb, offset); + skb->ip_summed = CHECKSUM_UNNECESSARY; + return 0; +} + static int nft_payload_l4csum_update(const struct nft_pktinfo *pkt, struct sk_buff *skb, __wsum fsum, __wsum tsum) @@ -587,6 +601,13 @@ static void nft_payload_set_eval(const struct nft_expr *expr, skb_store_bits(skb, offset, src, priv->len) < 0) goto err; + if (priv->csum_type == NFT_PAYLOAD_CSUM_SCTP && + pkt->tprot == IPPROTO_SCTP && + skb->ip_summed != CHECKSUM_PARTIAL) { + if (nft_payload_csum_sctp(skb, pkt->xt.thoff)) + goto err; + } + return; err: regs->verdict.code = NFT_BREAK; @@ -623,6 +644,13 @@ static int nft_payload_set_init(const struct nft_ctx *ctx, case NFT_PAYLOAD_CSUM_NONE: case NFT_PAYLOAD_CSUM_INET: break; + case NFT_PAYLOAD_CSUM_SCTP: + if (priv->base != NFT_PAYLOAD_TRANSPORT_HEADER) + return -EINVAL; + + if (priv->csum_offset != offsetof(struct sctphdr, checksum)) + return -EINVAL; + break; default: return -EOPNOTSUPP; }