From patchwork Mon Mar 9 17:14:25 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Pablo Neira Ayuso X-Patchwork-Id: 448127 X-Patchwork-Delegate: pablo@netfilter.org Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 205881401AA for ; Tue, 10 Mar 2015 04:12:51 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753647AbbCIRLF (ORCPT ); Mon, 9 Mar 2015 13:11:05 -0400 Received: from mail.us.es ([193.147.175.20]:47185 "EHLO mail.us.es" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753597AbbCIRLB (ORCPT ); Mon, 9 Mar 2015 13:11:01 -0400 Received: (qmail 9410 invoked from network); 9 Mar 2015 18:11:00 +0100 Received: from unknown (HELO us.es) (192.168.2.15) by us.es with SMTP; 9 Mar 2015 18:11:00 +0100 Received: (qmail 23276 invoked by uid 507); 9 Mar 2015 17:11:00 -0000 X-Qmail-Scanner-Diagnostics: from 127.0.0.1 by antivirus5 (envelope-from , uid 501) with qmail-scanner-2.10 (clamdscan: 0.98.6/20168. spamassassin: 3.4.0. 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Processed in 2.139505 secs); 09 Mar 2015 17:11:00 -0000 X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on antivirus5 X-Spam-Level: X-Spam-Status: No, score=-103.2 required=7.5 tests=BAYES_50,SMTPAUTH_US, USER_IN_WHITELIST autolearn=disabled version=3.4.0 X-Spam-ASN: AS12715 87.216.0.0/16 X-Envelope-From: pablo@netfilter.org Received: from unknown (HELO antivirus5) (127.0.0.1) by us.es with SMTP; 9 Mar 2015 17:10:57 -0000 Received: from 192.168.1.13 (192.168.1.13) by antivirus5 (F-Secure/fsigk_smtp/412/antivirus5); Mon, 09 Mar 2015 18:10:57 +0100 (CET) X-Virus-Status: clean(F-Secure/fsigk_smtp/412/antivirus5) Received: (qmail 15473 invoked from network); 9 Mar 2015 18:10:56 +0100 Received: from 129.166.216.87.static.jazztel.es (HELO salvia.here) (pneira@us.es@87.216.166.129) by mail.us.es with SMTP; 9 Mar 2015 18:10:56 +0100 From: Pablo Neira Ayuso To: netfilter-devel@vger.kernel.org Cc: davem@davemloft.net, netdev@vger.kernel.org Subject: [PATCH 02/12] netfilter: bridge: rework reject handling Date: Mon, 9 Mar 2015 18:14:25 +0100 Message-Id: <1425921275-9171-3-git-send-email-pablo@netfilter.org> X-Mailer: git-send-email 1.7.10.4 In-Reply-To: <1425921275-9171-1-git-send-email-pablo@netfilter.org> References: <1425921275-9171-1-git-send-email-pablo@netfilter.org> Sender: netfilter-devel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netfilter-devel@vger.kernel.org From: Florian Westphal bridge reject handling is not straightforward, there are many subtle differences depending on configuration. skb->dev is either the bridge port (PRE_ROUTING) or the bridge itself (INPUT), so we need to use indev instead. Also, checksum validation will only work reliably if we trim skb according to the l3 header size. While at it, add csum validation for ipv6 and skip existing tests if skb was already checked e.g. by GRO. Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso --- net/bridge/netfilter/nft_reject_bridge.c | 84 +++++++++++++++++++++++------- 1 file changed, 66 insertions(+), 18 deletions(-) diff --git a/net/bridge/netfilter/nft_reject_bridge.c b/net/bridge/netfilter/nft_reject_bridge.c index 3244aea..5c6c965 100644 --- a/net/bridge/netfilter/nft_reject_bridge.c +++ b/net/bridge/netfilter/nft_reject_bridge.c @@ -21,6 +21,7 @@ #include #include #include +#include #include "../br_private.h" static void nft_reject_br_push_etherhdr(struct sk_buff *oldskb, @@ -36,7 +37,12 @@ static void nft_reject_br_push_etherhdr(struct sk_buff *oldskb, skb_pull(nskb, ETH_HLEN); } -static void nft_reject_br_send_v4_tcp_reset(struct sk_buff *oldskb, int hook) +/* We cannot use oldskb->dev, it can be either bridge device (NF_BRIDGE INPUT) + * or the bridge port (NF_BRIDGE PREROUTING). + */ +static void nft_reject_br_send_v4_tcp_reset(struct sk_buff *oldskb, + const struct net_device *dev, + int hook) { struct sk_buff *nskb; struct iphdr *niph; @@ -65,11 +71,12 @@ static void nft_reject_br_send_v4_tcp_reset(struct sk_buff *oldskb, int hook) nft_reject_br_push_etherhdr(oldskb, nskb); - br_deliver(br_port_get_rcu(oldskb->dev), nskb); + br_deliver(br_port_get_rcu(dev), nskb); } -static void nft_reject_br_send_v4_unreach(struct sk_buff *oldskb, int hook, - u8 code) +static void nft_reject_br_send_v4_unreach(struct sk_buff *oldskb, + const struct net_device *dev, + int hook, u8 code) { struct sk_buff *nskb; struct iphdr *niph; @@ -77,8 +84,9 @@ static void nft_reject_br_send_v4_unreach(struct sk_buff *oldskb, int hook, unsigned int len; void *payload; __wsum csum; + u8 proto; - if (!nft_bridge_iphdr_validate(oldskb)) + if (oldskb->csum_bad || !nft_bridge_iphdr_validate(oldskb)) return; /* IP header checks: fragment. */ @@ -91,7 +99,17 @@ static void nft_reject_br_send_v4_unreach(struct sk_buff *oldskb, int hook, if (!pskb_may_pull(oldskb, len)) return; - if (nf_ip_checksum(oldskb, hook, ip_hdrlen(oldskb), 0)) + if (pskb_trim_rcsum(oldskb, htons(ip_hdr(oldskb)->tot_len))) + return; + + if (ip_hdr(oldskb)->protocol == IPPROTO_TCP || + ip_hdr(oldskb)->protocol == IPPROTO_UDP) + proto = ip_hdr(oldskb)->protocol; + else + proto = 0; + + if (!skb_csum_unnecessary(oldskb) && + nf_ip_checksum(oldskb, hook, ip_hdrlen(oldskb), proto)) return; nskb = alloc_skb(sizeof(struct iphdr) + sizeof(struct icmphdr) + @@ -120,11 +138,13 @@ static void nft_reject_br_send_v4_unreach(struct sk_buff *oldskb, int hook, nft_reject_br_push_etherhdr(oldskb, nskb); - br_deliver(br_port_get_rcu(oldskb->dev), nskb); + br_deliver(br_port_get_rcu(dev), nskb); } static void nft_reject_br_send_v6_tcp_reset(struct net *net, - struct sk_buff *oldskb, int hook) + struct sk_buff *oldskb, + const struct net_device *dev, + int hook) { struct sk_buff *nskb; const struct tcphdr *oth; @@ -152,12 +172,37 @@ static void nft_reject_br_send_v6_tcp_reset(struct net *net, nft_reject_br_push_etherhdr(oldskb, nskb); - br_deliver(br_port_get_rcu(oldskb->dev), nskb); + br_deliver(br_port_get_rcu(dev), nskb); +} + +static bool reject6_br_csum_ok(struct sk_buff *skb, int hook) +{ + const struct ipv6hdr *ip6h = ipv6_hdr(skb); + int thoff; + __be16 fo; + u8 proto = ip6h->nexthdr; + + if (skb->csum_bad) + return false; + + if (skb_csum_unnecessary(skb)) + return true; + + if (ip6h->payload_len && + pskb_trim_rcsum(skb, ntohs(ip6h->payload_len) + sizeof(*ip6h))) + return false; + + thoff = ipv6_skip_exthdr(skb, ((u8*)(ip6h+1) - skb->data), &proto, &fo); + if (thoff < 0 || thoff >= skb->len || (fo & htons(~0x7)) != 0) + return false; + + return nf_ip6_checksum(skb, hook, thoff, proto) == 0; } static void nft_reject_br_send_v6_unreach(struct net *net, - struct sk_buff *oldskb, int hook, - u8 code) + struct sk_buff *oldskb, + const struct net_device *dev, + int hook, u8 code) { struct sk_buff *nskb; struct ipv6hdr *nip6h; @@ -176,6 +221,9 @@ static void nft_reject_br_send_v6_unreach(struct net *net, if (!pskb_may_pull(oldskb, len)) return; + if (!reject6_br_csum_ok(oldskb, hook)) + return; + nskb = alloc_skb(sizeof(struct iphdr) + sizeof(struct icmp6hdr) + LL_MAX_HEADER + len, GFP_ATOMIC); if (!nskb) @@ -205,7 +253,7 @@ static void nft_reject_br_send_v6_unreach(struct net *net, nft_reject_br_push_etherhdr(oldskb, nskb); - br_deliver(br_port_get_rcu(oldskb->dev), nskb); + br_deliver(br_port_get_rcu(dev), nskb); } static void nft_reject_bridge_eval(const struct nft_expr *expr, @@ -224,16 +272,16 @@ static void nft_reject_bridge_eval(const struct nft_expr *expr, case htons(ETH_P_IP): switch (priv->type) { case NFT_REJECT_ICMP_UNREACH: - nft_reject_br_send_v4_unreach(pkt->skb, + nft_reject_br_send_v4_unreach(pkt->skb, pkt->in, pkt->ops->hooknum, priv->icmp_code); break; case NFT_REJECT_TCP_RST: - nft_reject_br_send_v4_tcp_reset(pkt->skb, + nft_reject_br_send_v4_tcp_reset(pkt->skb, pkt->in, pkt->ops->hooknum); break; case NFT_REJECT_ICMPX_UNREACH: - nft_reject_br_send_v4_unreach(pkt->skb, + nft_reject_br_send_v4_unreach(pkt->skb, pkt->in, pkt->ops->hooknum, nft_reject_icmp_code(priv->icmp_code)); break; @@ -242,16 +290,16 @@ static void nft_reject_bridge_eval(const struct nft_expr *expr, case htons(ETH_P_IPV6): switch (priv->type) { case NFT_REJECT_ICMP_UNREACH: - nft_reject_br_send_v6_unreach(net, pkt->skb, + nft_reject_br_send_v6_unreach(net, pkt->skb, pkt->in, pkt->ops->hooknum, priv->icmp_code); break; case NFT_REJECT_TCP_RST: - nft_reject_br_send_v6_tcp_reset(net, pkt->skb, + nft_reject_br_send_v6_tcp_reset(net, pkt->skb, pkt->in, pkt->ops->hooknum); break; case NFT_REJECT_ICMPX_UNREACH: - nft_reject_br_send_v6_unreach(net, pkt->skb, + nft_reject_br_send_v6_unreach(net, pkt->skb, pkt->in, pkt->ops->hooknum, nft_reject_icmpv6_code(priv->icmp_code)); break;