From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-1524142-1518326191-2-1772743637277333032 X-Sieve: CMU Sieve 3.0 X-Spam-known-sender: no X-Spam-score: 0.0 X-Spam-hits: BAYES_00 -1.9, HEADER_FROM_DIFFERENT_DOMAINS 0.001, ME_NOAUTH 0.01, RCVD_IN_DNSWL_HI -5, T_RP_MATCHES_RCVD -0.01, LANGUAGES en, BAYES_USED global, SA_VERSION 3.4.0 X-Spam-source: IP='209.132.180.67', Host='vger.kernel.org', Country='US', FromHeader='uk', MailFrom='org' X-Spam-charsets: plain='UTF-8' X-Resolved-to: greg@kroah.com X-Delivered-to: greg@kroah.com X-Mail-from: stable-owner@vger.kernel.org ARC-Seal: i=1; a=rsa-sha256; cv=none; d=messagingengine.com; s=arctest; t=1518326191; b=ZDpKu8Re22Jbhqabmsh7ncx6QEpR0bcnD1+0hAsobJSY08r Nz2kUYnnmTW4aJgCAQmeR2iICt6NVpb+1sfOfj2rFm19crfOz4hJB/22b9JvnE8N Z5Q9ehMs5+yBv9xMqU/LgYzCqwn1+TyjfMKls95bkF+GcKjnmLsMDK8lqfs4TKEe cYHn6dOHTQpeFrBKyUjxzpo2S7/+u8uipb5B/gqC9f+XDTZSal/EeQUsBXDS6c1R 5XhYyWQAxRXhIAue9F4vh+odb5apwjDrBUyuDY6Caz8REMdiwhPcaewgfVHUxcLj 951GXovn6iRa4iaKHx9qYXhsTmIqi8QrBSQtQfQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=content-type:content-transfer-encoding :mime-version:from:to:cc:date:message-id:subject:in-reply-to :sender:list-id; s=arctest; t=1518326191; bh=WbjqCDkE/yATie1Dfau 1jlk7Jynml7OAtcAhjQekAag=; b=WWSTrbrtsDnJsZWvjXze7w+KkoTc9/ByLVl pImTZIUDL1ncrIZySx3oBzdR6miLN2776DqPGTf8Hx49L/mQalWlJ6iIcLCUS2AD p0BR7Gc0hKN4NP71D0UbS71Czg/aFtO8qRMjFmWIrAjioMGob2oVRxs0y/8F9xWs QW5wPQqg6eyn4UEln/olA7ucU2LG4cWJAxb9wrw5nUu3m5feeIk9Xaa1lB2QePxJ jMvq6v2An2U/xC6fcobGsG33f/9JN4cfU9V11M5ySDCM6OQJxTKmQzrFGUZsv06T VV8EuWjjTJ5TxmseZPyUyyPx8Tukr24KVaKKArQa9z3Iqi9zanw== ARC-Authentication-Results: i=1; mx2.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=decadent.org.uk; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=decadent.org.uk header.result=pass header_is_org_domain=yes Authentication-Results: mx2.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=decadent.org.uk; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=decadent.org.uk header.result=pass header_is_org_domain=yes Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753893AbeBKFOT (ORCPT ); Sun, 11 Feb 2018 00:14:19 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:41378 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752601AbeBKEdl (ORCPT ); Sat, 10 Feb 2018 23:33:41 -0500 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Rafal Kupka" , "Pablo Neira Ayuso" Date: Sun, 11 Feb 2018 04:20:06 +0000 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.2 61/79] netfilter: xt_TCPOPTSTRIP: fix possible mangling beyond packet boundary In-Reply-To: X-SA-Exim-Connect-IP: 2a02:8011:400e:2:6f00:88c8:c921:d332 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: stable-owner@vger.kernel.org X-Mailing-List: stable@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 3.2.99-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Pablo Neira Ayuso commit bc6bcb59dd7c184d229f9e86d08aa56059938a4c upstream. This target assumes that tcph->doff is well-formed, that may be well not the case. Add extra sanity checkings to avoid possible crash due to read/write out of the real packet boundary. After this patch, the default action on malformed TCP packets is to drop them. Moreover, fragments are skipped. Reported-by: Rafal Kupka Signed-off-by: Pablo Neira Ayuso Signed-off-by: Ben Hutchings --- net/netfilter/xt_TCPOPTSTRIP.c | 17 ++++++++++++++--- 1 file changed, 14 insertions(+), 3 deletions(-) --- a/net/netfilter/xt_TCPOPTSTRIP.c +++ b/net/netfilter/xt_TCPOPTSTRIP.c @@ -30,17 +30,28 @@ static inline unsigned int optlen(const static unsigned int tcpoptstrip_mangle_packet(struct sk_buff *skb, - const struct xt_tcpoptstrip_target_info *info, + const struct xt_action_param *par, unsigned int tcphoff, unsigned int minlen) { + const struct xt_tcpoptstrip_target_info *info = par->targinfo; unsigned int optl, i, j; struct tcphdr *tcph; u_int16_t n, o; u_int8_t *opt; + int len; + + /* This is a fragment, no TCP header is available */ + if (par->fragoff != 0) + return XT_CONTINUE; if (!skb_make_writable(skb, skb->len)) return NF_DROP; + len = skb->len - tcphoff; + if (len < (int)sizeof(struct tcphdr) || + tcp_hdr(skb)->doff * 4 > len) + return NF_DROP; + tcph = (struct tcphdr *)(skb_network_header(skb) + tcphoff); opt = (u_int8_t *)tcph; @@ -76,7 +87,7 @@ tcpoptstrip_mangle_packet(struct sk_buff static unsigned int tcpoptstrip_tg4(struct sk_buff *skb, const struct xt_action_param *par) { - return tcpoptstrip_mangle_packet(skb, par->targinfo, ip_hdrlen(skb), + return tcpoptstrip_mangle_packet(skb, par, ip_hdrlen(skb), sizeof(struct iphdr) + sizeof(struct tcphdr)); } @@ -93,7 +104,7 @@ tcpoptstrip_tg6(struct sk_buff *skb, con if (tcphoff < 0) return NF_DROP; - return tcpoptstrip_mangle_packet(skb, par->targinfo, tcphoff, + return tcpoptstrip_mangle_packet(skb, par, tcphoff, sizeof(*ipv6h) + sizeof(struct tcphdr)); } #endif