From patchwork Fri Oct 29 14:59:53 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Pablo Neira Ayuso X-Patchwork-Id: 1548064 X-Patchwork-Delegate: pablo@netfilter.org Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org (client-ip=23.128.96.18; helo=vger.kernel.org; envelope-from=netfilter-devel-owner@vger.kernel.org; receiver=) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by bilbo.ozlabs.org (Postfix) with ESMTP id 4Hglw02Nc0z9sRN for ; Sat, 30 Oct 2021 02:00:00 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229623AbhJ2PC1 (ORCPT ); Fri, 29 Oct 2021 11:02:27 -0400 Received: from mail.netfilter.org ([217.70.188.207]:52830 "EHLO mail.netfilter.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229542AbhJ2PC0 (ORCPT ); Fri, 29 Oct 2021 11:02:26 -0400 Received: from localhost.localdomain (unknown [78.30.32.163]) by mail.netfilter.org (Postfix) with ESMTPSA id 1EF2563586 for ; Fri, 29 Oct 2021 16:58:07 +0200 (CEST) From: Pablo Neira Ayuso To: netfilter-devel@vger.kernel.org Subject: [PACH nf-next,v4] netfilter: nft_payload: support for inner header matching / mangling Date: Fri, 29 Oct 2021 16:59:53 +0200 Message-Id: <20211029145953.11155-1-pablo@netfilter.org> X-Mailer: git-send-email 2.30.2 MIME-Version: 1.0 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 --- v4: check for nft_payload_inner_offset == -1, then goto err. include/net/netfilter/nf_tables.h | 2 + include/uapi/linux/netfilter/nf_tables.h | 2 + net/netfilter/nft_payload.c | 56 +++++++++++++++++++++++- 3 files changed, 58 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..cbfe4e4a4ad7 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 +152,11 @@ 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); + if (offset < 0) + goto err; + break; default: BUG(); } @@ -614,6 +659,11 @@ 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); + if (offset < 0) + goto err; + break; default: BUG(); } @@ -622,7 +672,8 @@ 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 +792,7 @@ 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 +811,7 @@ 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;