From patchwork Mon Mar 22 23:56:22 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: 407440 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=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI, 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 D88E4C433FC for ; Mon, 22 Mar 2021 23:57:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AF026619A4 for ; Mon, 22 Mar 2021 23:57:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231375AbhCVX5X (ORCPT ); Mon, 22 Mar 2021 19:57:23 -0400 Received: from mail.netfilter.org ([217.70.188.207]:58338 "EHLO mail.netfilter.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230450AbhCVX4s (ORCPT ); Mon, 22 Mar 2021 19:56:48 -0400 Received: from localhost.localdomain (unknown [90.77.255.23]) by mail.netfilter.org (Postfix) with ESMTPSA id 4F3186312F; Tue, 23 Mar 2021 00:56:33 +0100 (CET) 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 04/10] netfilter: flowtable: consolidate skb_try_make_writable() call Date: Tue, 23 Mar 2021 00:56:22 +0100 Message-Id: <20210322235628.2204-5-pablo@netfilter.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20210322235628.2204-1-pablo@netfilter.org> References: <20210322235628.2204-1-pablo@netfilter.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Fetch the layer 4 header size to be mangled by NAT when building the tuple, then use it to make writable the network and the transport headers. After this update, the NAT routines now assumes that the skbuff area is writable. Do the pointer refetch only after the single skb_try_make_writable() call. Signed-off-by: Pablo Neira Ayuso --- net/netfilter/nf_flow_table_core.c | 12 ----- net/netfilter/nf_flow_table_ip.c | 74 +++++++++++++----------------- 2 files changed, 31 insertions(+), 55 deletions(-) diff --git a/net/netfilter/nf_flow_table_core.c b/net/netfilter/nf_flow_table_core.c index 5fa657b8e03d..ff5d94b644ac 100644 --- a/net/netfilter/nf_flow_table_core.c +++ b/net/netfilter/nf_flow_table_core.c @@ -395,9 +395,6 @@ static int nf_flow_nat_port_tcp(struct sk_buff *skb, unsigned int thoff, { struct tcphdr *tcph; - if (skb_try_make_writable(skb, thoff + sizeof(*tcph))) - return -1; - tcph = (void *)(skb_network_header(skb) + thoff); inet_proto_csum_replace2(&tcph->check, skb, port, new_port, false); @@ -409,9 +406,6 @@ static int nf_flow_nat_port_udp(struct sk_buff *skb, unsigned int thoff, { struct udphdr *udph; - if (skb_try_make_writable(skb, thoff + sizeof(*udph))) - return -1; - udph = (void *)(skb_network_header(skb) + thoff); if (udph->check || skb->ip_summed == CHECKSUM_PARTIAL) { inet_proto_csum_replace2(&udph->check, skb, port, @@ -447,9 +441,6 @@ int nf_flow_snat_port(const struct flow_offload *flow, struct flow_ports *hdr; __be16 port, new_port; - if (skb_try_make_writable(skb, thoff + sizeof(*hdr))) - return -1; - hdr = (void *)(skb_network_header(skb) + thoff); switch (dir) { @@ -478,9 +469,6 @@ int nf_flow_dnat_port(const struct flow_offload *flow, struct flow_ports *hdr; __be16 port, new_port; - if (skb_try_make_writable(skb, thoff + sizeof(*hdr))) - return -1; - hdr = (void *)(skb_network_header(skb) + thoff); switch (dir) { diff --git a/net/netfilter/nf_flow_table_ip.c b/net/netfilter/nf_flow_table_ip.c index a698dbe28ef5..2b8ee5dcef64 100644 --- a/net/netfilter/nf_flow_table_ip.c +++ b/net/netfilter/nf_flow_table_ip.c @@ -39,9 +39,6 @@ static int nf_flow_nat_ip_tcp(struct sk_buff *skb, unsigned int thoff, { struct tcphdr *tcph; - if (skb_try_make_writable(skb, thoff + sizeof(*tcph))) - return -1; - tcph = (void *)(skb_network_header(skb) + thoff); inet_proto_csum_replace4(&tcph->check, skb, addr, new_addr, true); @@ -53,9 +50,6 @@ static int nf_flow_nat_ip_udp(struct sk_buff *skb, unsigned int thoff, { struct udphdr *udph; - if (skb_try_make_writable(skb, thoff + sizeof(*udph))) - return -1; - udph = (void *)(skb_network_header(skb) + thoff); if (udph->check || skb->ip_summed == CHECKSUM_PARTIAL) { inet_proto_csum_replace4(&udph->check, skb, addr, @@ -136,19 +130,17 @@ static int nf_flow_dnat_ip(const struct flow_offload *flow, struct sk_buff *skb, } static int nf_flow_nat_ip(const struct flow_offload *flow, struct sk_buff *skb, - unsigned int thoff, enum flow_offload_tuple_dir dir) + unsigned int thoff, enum flow_offload_tuple_dir dir, + struct iphdr *iph) { - struct iphdr *iph = ip_hdr(skb); - if (test_bit(NF_FLOW_SNAT, &flow->flags) && (nf_flow_snat_port(flow, skb, thoff, iph->protocol, dir) < 0 || - nf_flow_snat_ip(flow, skb, ip_hdr(skb), thoff, dir) < 0)) + nf_flow_snat_ip(flow, skb, iph, thoff, dir) < 0)) return -1; - iph = ip_hdr(skb); if (test_bit(NF_FLOW_DNAT, &flow->flags) && (nf_flow_dnat_port(flow, skb, thoff, iph->protocol, dir) < 0 || - nf_flow_dnat_ip(flow, skb, ip_hdr(skb), thoff, dir) < 0)) + nf_flow_dnat_ip(flow, skb, iph, thoff, dir) < 0)) return -1; return 0; @@ -160,10 +152,10 @@ static bool ip_has_options(unsigned int thoff) } static int nf_flow_tuple_ip(struct sk_buff *skb, const struct net_device *dev, - struct flow_offload_tuple *tuple) + struct flow_offload_tuple *tuple, u32 *hdrsize) { - unsigned int thoff, hdrsize; struct flow_ports *ports; + unsigned int thoff; struct iphdr *iph; if (!pskb_may_pull(skb, sizeof(*iph))) @@ -178,10 +170,10 @@ static int nf_flow_tuple_ip(struct sk_buff *skb, const struct net_device *dev, switch (iph->protocol) { case IPPROTO_TCP: - hdrsize = sizeof(struct tcphdr); + *hdrsize = sizeof(struct tcphdr); break; case IPPROTO_UDP: - hdrsize = sizeof(struct udphdr); + *hdrsize = sizeof(struct udphdr); break; default: return -1; @@ -191,7 +183,7 @@ static int nf_flow_tuple_ip(struct sk_buff *skb, const struct net_device *dev, return -1; thoff = iph->ihl * 4; - if (!pskb_may_pull(skb, thoff + hdrsize)) + if (!pskb_may_pull(skb, thoff + *hdrsize)) return -1; iph = ip_hdr(skb); @@ -252,11 +244,12 @@ nf_flow_offload_ip_hook(void *priv, struct sk_buff *skb, unsigned int thoff; struct iphdr *iph; __be32 nexthop; + u32 hdrsize; if (skb->protocol != htons(ETH_P_IP)) return NF_ACCEPT; - if (nf_flow_tuple_ip(skb, state->in, &tuple) < 0) + if (nf_flow_tuple_ip(skb, state->in, &tuple, &hdrsize) < 0) return NF_ACCEPT; tuplehash = flow_offload_lookup(flow_table, &tuple); @@ -271,11 +264,13 @@ nf_flow_offload_ip_hook(void *priv, struct sk_buff *skb, if (unlikely(nf_flow_exceeds_mtu(skb, flow->tuplehash[dir].tuple.mtu))) return NF_ACCEPT; - if (skb_try_make_writable(skb, sizeof(*iph))) + iph = ip_hdr(skb); + thoff = iph->ihl * 4; + if (skb_try_make_writable(skb, thoff + hdrsize)) return NF_DROP; - thoff = ip_hdr(skb)->ihl * 4; - if (nf_flow_state_check(flow, ip_hdr(skb)->protocol, skb, thoff)) + iph = ip_hdr(skb); + if (nf_flow_state_check(flow, iph->protocol, skb, thoff)) return NF_ACCEPT; flow_offload_refresh(flow_table, flow); @@ -285,10 +280,9 @@ nf_flow_offload_ip_hook(void *priv, struct sk_buff *skb, return NF_ACCEPT; } - if (nf_flow_nat_ip(flow, skb, thoff, dir) < 0) + if (nf_flow_nat_ip(flow, skb, thoff, dir, iph) < 0) return NF_DROP; - iph = ip_hdr(skb); ip_decrease_ttl(iph); skb->tstamp = 0; @@ -317,9 +311,6 @@ static int nf_flow_nat_ipv6_tcp(struct sk_buff *skb, unsigned int thoff, { struct tcphdr *tcph; - if (skb_try_make_writable(skb, thoff + sizeof(*tcph))) - return -1; - tcph = (void *)(skb_network_header(skb) + thoff); inet_proto_csum_replace16(&tcph->check, skb, addr->s6_addr32, new_addr->s6_addr32, true); @@ -333,9 +324,6 @@ static int nf_flow_nat_ipv6_udp(struct sk_buff *skb, unsigned int thoff, { struct udphdr *udph; - if (skb_try_make_writable(skb, thoff + sizeof(*udph))) - return -1; - udph = (void *)(skb_network_header(skb) + thoff); if (udph->check || skb->ip_summed == CHECKSUM_PARTIAL) { inet_proto_csum_replace16(&udph->check, skb, addr->s6_addr32, @@ -417,31 +405,30 @@ static int nf_flow_dnat_ipv6(const struct flow_offload *flow, static int nf_flow_nat_ipv6(const struct flow_offload *flow, struct sk_buff *skb, - enum flow_offload_tuple_dir dir) + enum flow_offload_tuple_dir dir, + struct ipv6hdr *ip6h) { - struct ipv6hdr *ip6h = ipv6_hdr(skb); unsigned int thoff = sizeof(*ip6h); if (test_bit(NF_FLOW_SNAT, &flow->flags) && (nf_flow_snat_port(flow, skb, thoff, ip6h->nexthdr, dir) < 0 || - nf_flow_snat_ipv6(flow, skb, ipv6_hdr(skb), thoff, dir) < 0)) + nf_flow_snat_ipv6(flow, skb, ip6h, thoff, dir) < 0)) return -1; - ip6h = ipv6_hdr(skb); if (test_bit(NF_FLOW_DNAT, &flow->flags) && (nf_flow_dnat_port(flow, skb, thoff, ip6h->nexthdr, dir) < 0 || - nf_flow_dnat_ipv6(flow, skb, ipv6_hdr(skb), thoff, dir) < 0)) + nf_flow_dnat_ipv6(flow, skb, ip6h, thoff, dir) < 0)) return -1; return 0; } static int nf_flow_tuple_ipv6(struct sk_buff *skb, const struct net_device *dev, - struct flow_offload_tuple *tuple) + struct flow_offload_tuple *tuple, u32 *hdrsize) { - unsigned int thoff, hdrsize; struct flow_ports *ports; struct ipv6hdr *ip6h; + unsigned int thoff; if (!pskb_may_pull(skb, sizeof(*ip6h))) return -1; @@ -450,10 +437,10 @@ static int nf_flow_tuple_ipv6(struct sk_buff *skb, const struct net_device *dev, switch (ip6h->nexthdr) { case IPPROTO_TCP: - hdrsize = sizeof(struct tcphdr); + *hdrsize = sizeof(struct tcphdr); break; case IPPROTO_UDP: - hdrsize = sizeof(struct udphdr); + *hdrsize = sizeof(struct udphdr); break; default: return -1; @@ -463,7 +450,7 @@ static int nf_flow_tuple_ipv6(struct sk_buff *skb, const struct net_device *dev, return -1; thoff = sizeof(*ip6h); - if (!pskb_may_pull(skb, thoff + hdrsize)) + if (!pskb_may_pull(skb, thoff + *hdrsize)) return -1; ip6h = ipv6_hdr(skb); @@ -493,11 +480,12 @@ nf_flow_offload_ipv6_hook(void *priv, struct sk_buff *skb, struct net_device *outdev; struct ipv6hdr *ip6h; struct rt6_info *rt; + u32 hdrsize; if (skb->protocol != htons(ETH_P_IPV6)) return NF_ACCEPT; - if (nf_flow_tuple_ipv6(skb, state->in, &tuple) < 0) + if (nf_flow_tuple_ipv6(skb, state->in, &tuple, &hdrsize) < 0) return NF_ACCEPT; tuplehash = flow_offload_lookup(flow_table, &tuple); @@ -523,13 +511,13 @@ nf_flow_offload_ipv6_hook(void *priv, struct sk_buff *skb, return NF_ACCEPT; } - if (skb_try_make_writable(skb, sizeof(*ip6h))) + if (skb_try_make_writable(skb, sizeof(*ip6h) + hdrsize)) return NF_DROP; - if (nf_flow_nat_ipv6(flow, skb, dir) < 0) + ip6h = ipv6_hdr(skb); + if (nf_flow_nat_ipv6(flow, skb, dir, ip6h) < 0) return NF_DROP; - ip6h = ipv6_hdr(skb); ip6h->hop_limit--; skb->tstamp = 0;