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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id DDFA7C433F5 for ; Fri, 29 Oct 2021 14:45:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BC995610CF for ; Fri, 29 Oct 2021 14:45:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229607AbhJ2OsU (ORCPT ); Fri, 29 Oct 2021 10:48:20 -0400 Received: from mail.netfilter.org ([217.70.188.207]:52798 "EHLO mail.netfilter.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229558AbhJ2OsU (ORCPT ); Fri, 29 Oct 2021 10:48:20 -0400 Received: from localhost.localdomain (unknown [78.30.32.163]) by mail.netfilter.org (Postfix) with ESMTPSA id D6F3963586 for ; Fri, 29 Oct 2021 16:43:59 +0200 (CEST) From: Pablo Neira Ayuso To: netfilter-devel@vger.kernel.org Subject: [PATCH nf-next,v3 2/2] netfilter: nft_payload: support for inner header matching / mangling Date: Fri, 29 Oct 2021 16:45:12 +0200 Message-Id: <20211029144512.9570-1-pablo@netfilter.org> X-Mailer: git-send-email 2.30.2 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: netfilter-devel@vger.kernel.org Allow to match and mangle on inner headers / payload data after the transport header. There is a new field in the pktinfo structure that stores the inner header offset which is calculated only when requested. Only TCP and UDP supported at this stage. Signed-off-by: Pablo Neira Ayuso --- v3: - check for NFT_PKTINFO_L4PROTO from __nft_payload_inner_offset() - update commit description include/net/netfilter/nf_tables.h | 2 + include/uapi/linux/netfilter/nf_tables.h | 2 + net/netfilter/nft_payload.c | 52 +++++++++++++++++++++++- 3 files changed, 54 insertions(+), 2 deletions(-) diff --git a/include/net/netfilter/nf_tables.h b/include/net/netfilter/nf_tables.h index 7e3188cf4a7d..a0d9e0b47ab8 100644 --- a/include/net/netfilter/nf_tables.h +++ b/include/net/netfilter/nf_tables.h @@ -23,6 +23,7 @@ struct module; enum { NFT_PKTINFO_L4PROTO = (1 << 0), + NFT_PKTINFO_INNER = (1 << 1), }; struct nft_pktinfo { @@ -32,6 +33,7 @@ struct nft_pktinfo { u8 tprot; u16 fragoff; unsigned int thoff; + unsigned int inneroff; }; static inline struct sock *nft_sk(const struct nft_pktinfo *pkt) diff --git a/include/uapi/linux/netfilter/nf_tables.h b/include/uapi/linux/netfilter/nf_tables.h index 08db4ee06ab6..466fd3f4447c 100644 --- a/include/uapi/linux/netfilter/nf_tables.h +++ b/include/uapi/linux/netfilter/nf_tables.h @@ -753,11 +753,13 @@ enum nft_dynset_attributes { * @NFT_PAYLOAD_LL_HEADER: link layer header * @NFT_PAYLOAD_NETWORK_HEADER: network header * @NFT_PAYLOAD_TRANSPORT_HEADER: transport header + * @NFT_PAYLOAD_INNER_HEADER: inner header / payload */ enum nft_payload_bases { NFT_PAYLOAD_LL_HEADER, NFT_PAYLOAD_NETWORK_HEADER, NFT_PAYLOAD_TRANSPORT_HEADER, + NFT_PAYLOAD_INNER_HEADER, }; /** diff --git a/net/netfilter/nft_payload.c b/net/netfilter/nft_payload.c index d1cd6583ee00..f40995fb7571 100644 --- a/net/netfilter/nft_payload.c +++ b/net/netfilter/nft_payload.c @@ -22,6 +22,7 @@ #include #include #include +#include #include static bool nft_payload_rebuild_vlan_hdr(const struct sk_buff *skb, int mac_off, @@ -79,6 +80,45 @@ nft_payload_copy_vlan(u32 *d, const struct sk_buff *skb, u8 offset, u8 len) return skb_copy_bits(skb, offset + mac_off, dst_u8, len) == 0; } +static int __nft_payload_inner_offset(struct nft_pktinfo *pkt) +{ + unsigned int thoff = nft_thoff(pkt); + + if (!(pkt->flags & NFT_PKTINFO_L4PROTO)) + return -1; + + switch (pkt->tprot) { + case IPPROTO_UDP: + pkt->inneroff = thoff + sizeof(struct udphdr); + break; + case IPPROTO_TCP: { + struct tcphdr *th, _tcph; + + th = skb_header_pointer(pkt->skb, thoff, sizeof(_tcph), &_tcph); + if (!th) + return -1; + + pkt->inneroff = thoff + __tcp_hdrlen(th); + } + break; + default: + return -1; + } + + pkt->flags |= NFT_PKTINFO_INNER; + + return 0; +} + +static int nft_payload_inner_offset(const struct nft_pktinfo *pkt) +{ + if (!(pkt->flags & NFT_PKTINFO_INNER) && + __nft_payload_inner_offset((struct nft_pktinfo *)pkt) < 0) + return -1; + + return pkt->inneroff; +} + void nft_payload_eval(const struct nft_expr *expr, struct nft_regs *regs, const struct nft_pktinfo *pkt) @@ -112,6 +152,9 @@ void nft_payload_eval(const struct nft_expr *expr, goto err; offset = nft_thoff(pkt); break; + case NFT_PAYLOAD_INNER_HEADER: + offset = nft_payload_inner_offset(pkt); + break; default: BUG(); } @@ -614,6 +657,9 @@ static void nft_payload_set_eval(const struct nft_expr *expr, goto err; offset = nft_thoff(pkt); break; + case NFT_PAYLOAD_INNER_HEADER: + offset = nft_payload_inner_offset(pkt); + break; default: BUG(); } @@ -622,7 +668,8 @@ static void nft_payload_set_eval(const struct nft_expr *expr, offset += priv->offset; if ((priv->csum_type == NFT_PAYLOAD_CSUM_INET || priv->csum_flags) && - (priv->base != NFT_PAYLOAD_TRANSPORT_HEADER || + ((priv->base != NFT_PAYLOAD_TRANSPORT_HEADER && + priv->base != NFT_PAYLOAD_INNER_HEADER) || skb->ip_summed != CHECKSUM_PARTIAL)) { fsum = skb_checksum(skb, offset, priv->len, 0); tsum = csum_partial(src, priv->len, 0); @@ -741,6 +788,7 @@ nft_payload_select_ops(const struct nft_ctx *ctx, case NFT_PAYLOAD_LL_HEADER: case NFT_PAYLOAD_NETWORK_HEADER: case NFT_PAYLOAD_TRANSPORT_HEADER: + case NFT_PAYLOAD_INNER_HEADER: break; default: return ERR_PTR(-EOPNOTSUPP); @@ -759,7 +807,7 @@ nft_payload_select_ops(const struct nft_ctx *ctx, len = ntohl(nla_get_be32(tb[NFTA_PAYLOAD_LEN])); if (len <= 4 && is_power_of_2(len) && IS_ALIGNED(offset, len) && - base != NFT_PAYLOAD_LL_HEADER) + base != NFT_PAYLOAD_LL_HEADER && base != NFT_PAYLOAD_INNER_HEADER) return &nft_payload_fast_ops; else return &nft_payload_ops; -- 2.30.2