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 X-Spam-Level: X-Spam-Status: No, score=-9.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham 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 E0F80C46460 for ; Sat, 1 Jun 2019 18:24:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BE94127747 for ; Sat, 1 Jun 2019 18:24:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726587AbfFASYQ (ORCPT ); Sat, 1 Jun 2019 14:24:16 -0400 Received: from mail.us.es ([193.147.175.20]:40076 "EHLO mail.us.es" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726826AbfFASYK (ORCPT ); Sat, 1 Jun 2019 14:24:10 -0400 Received: from antivirus1-rhel7.int (unknown [192.168.2.11]) by mail.us.es (Postfix) with ESMTP id 19A66FF126 for ; Sat, 1 Jun 2019 20:24:01 +0200 (CEST) Received: from antivirus1-rhel7.int (localhost [127.0.0.1]) by antivirus1-rhel7.int (Postfix) with ESMTP id 07746DA702 for ; Sat, 1 Jun 2019 20:24:01 +0200 (CEST) Received: by antivirus1-rhel7.int (Postfix, from userid 99) id D660EFF2E5; Sat, 1 Jun 2019 20:23:59 +0200 (CEST) Received: from antivirus1-rhel7.int (localhost [127.0.0.1]) by antivirus1-rhel7.int (Postfix) with ESMTP id 48369DA729; Sat, 1 Jun 2019 20:23:57 +0200 (CEST) Received: from 192.168.1.97 (192.168.1.97) by antivirus1-rhel7.int (F-Secure/fsigk_smtp/550/antivirus1-rhel7.int); Sat, 01 Jun 2019 20:23:57 +0200 (CEST) X-Virus-Status: clean(F-Secure/fsigk_smtp/550/antivirus1-rhel7.int) Received: from salvia.here (unknown [31.4.178.197]) (Authenticated sender: pneira@us.es) by entrada.int (Postfix) with ESMTPA id DC7124265A31; Sat, 1 Jun 2019 20:23:56 +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 Subject: [PATCH 13/15] netfilter: tcpmss, optstrip: prefer skb_ensure_writable Date: Sat, 1 Jun 2019 20:23:38 +0200 Message-Id: <20190601182340.2662-14-pablo@netfilter.org> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20190601182340.2662-1-pablo@netfilter.org> References: <20190601182340.2662-1-pablo@netfilter.org> X-Virus-Scanned: ClamAV using ClamSMTP Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Florian Westphal This also changes optstrip to only make the tcp header writeable rather than the entire packet. Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso --- net/netfilter/xt_TCPMSS.c | 2 +- net/netfilter/xt_TCPOPTSTRIP.c | 28 +++++++++++++--------------- 2 files changed, 14 insertions(+), 16 deletions(-) diff --git a/net/netfilter/xt_TCPMSS.c b/net/netfilter/xt_TCPMSS.c index 98efb202f8b4..3e24443ab81c 100644 --- a/net/netfilter/xt_TCPMSS.c +++ b/net/netfilter/xt_TCPMSS.c @@ -89,7 +89,7 @@ tcpmss_mangle_packet(struct sk_buff *skb, if (par->fragoff != 0) return 0; - if (!skb_make_writable(skb, skb->len)) + if (skb_ensure_writable(skb, skb->len)) return -1; len = skb->len - tcphoff; diff --git a/net/netfilter/xt_TCPOPTSTRIP.c b/net/netfilter/xt_TCPOPTSTRIP.c index eb92bffff11c..5a274813076a 100644 --- a/net/netfilter/xt_TCPOPTSTRIP.c +++ b/net/netfilter/xt_TCPOPTSTRIP.c @@ -31,33 +31,33 @@ static inline unsigned int optlen(const u_int8_t *opt, unsigned int offset) static unsigned int tcpoptstrip_mangle_packet(struct sk_buff *skb, const struct xt_action_param *par, - unsigned int tcphoff, unsigned int minlen) + unsigned int tcphoff) { const struct xt_tcpoptstrip_target_info *info = par->targinfo; + struct tcphdr *tcph, _th; unsigned int optl, i, j; - struct tcphdr *tcph; u_int16_t n, o; u_int8_t *opt; - int len, tcp_hdrlen; + int tcp_hdrlen; /* This is a fragment, no TCP header is available */ if (par->fragoff != 0) return XT_CONTINUE; - if (!skb_make_writable(skb, skb->len)) + tcph = skb_header_pointer(skb, tcphoff, sizeof(_th), &_th); + if (!tcph) return NF_DROP; - len = skb->len - tcphoff; - if (len < (int)sizeof(struct tcphdr)) - return NF_DROP; - - tcph = (struct tcphdr *)(skb_network_header(skb) + tcphoff); tcp_hdrlen = tcph->doff * 4; + if (tcp_hdrlen < sizeof(struct tcphdr)) + return NF_DROP; - if (len < tcp_hdrlen) + if (skb_ensure_writable(skb, tcphoff + tcp_hdrlen)) return NF_DROP; - opt = (u_int8_t *)tcph; + /* must reload tcph, might have been moved */ + tcph = (struct tcphdr *)(skb_network_header(skb) + tcphoff); + opt = (u8 *)tcph; /* * Walk through all TCP options - if we find some option to remove, @@ -91,8 +91,7 @@ tcpoptstrip_mangle_packet(struct sk_buff *skb, static unsigned int tcpoptstrip_tg4(struct sk_buff *skb, const struct xt_action_param *par) { - return tcpoptstrip_mangle_packet(skb, par, ip_hdrlen(skb), - sizeof(struct iphdr) + sizeof(struct tcphdr)); + return tcpoptstrip_mangle_packet(skb, par, ip_hdrlen(skb)); } #if IS_ENABLED(CONFIG_IP6_NF_MANGLE) @@ -109,8 +108,7 @@ tcpoptstrip_tg6(struct sk_buff *skb, const struct xt_action_param *par) if (tcphoff < 0) return NF_DROP; - return tcpoptstrip_mangle_packet(skb, par, tcphoff, - sizeof(*ipv6h) + sizeof(struct tcphdr)); + return tcpoptstrip_mangle_packet(skb, par, tcphoff); } #endif -- 2.11.0