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=-6.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, 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 94DF0C282C4 for ; Mon, 4 Feb 2019 10:42:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 653B52176F for ; Mon, 4 Feb 2019 10:42:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1549276979; bh=48BWwpaqsqNQ0TW1WyLdKb1Nk0TErV+LZ1u1cwOxEyE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=YRnqkHQ6QzpSgxXBjU6KiKm475QzIMXVPIKYeqByW6QM1UtSy+z/5NpMy+Uyrm21R kVsl6oc1zs1TFXSJWqtPpBGr3bUShHDq43o0mUoTenjjhw+q64fVyDgywpdYHnmESz a5sEb5/vteYOCn5yBsayIc9sRVX+v+NNvropermU= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730639AbfBDKm5 (ORCPT ); Mon, 4 Feb 2019 05:42:57 -0500 Received: from mail.kernel.org ([198.145.29.99]:40798 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730610AbfBDKmz (ORCPT ); Mon, 4 Feb 2019 05:42:55 -0500 Received: from localhost (5356596B.cm-6-7b.dynamic.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 6D2022075B; Mon, 4 Feb 2019 10:42:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1549276973; bh=48BWwpaqsqNQ0TW1WyLdKb1Nk0TErV+LZ1u1cwOxEyE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ZfKgHowvnB1eQmjU1qhX8R2802t0CVgUhk6blKkVhq5jcOIGPmcpFx8TRby22vd4T nLnRYRwDwKndlyWwUqhRORixQtkmGXErThHzrYWSAzJ/1HWhDRCKc1mYueHmZjTbfg txEM5q6xFV5Pvb5A0N5ZeJvY4U5kf8l1OgTO39JY= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jacob Wen , Guillaume Nault , "David S. Miller" Subject: [PATCH 4.9 11/30] l2tp: fix reading optional fields of L2TPv3 Date: Mon, 4 Feb 2019 11:36:49 +0100 Message-Id: <20190204103607.279496098@linuxfoundation.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190204103605.271746870@linuxfoundation.org> References: <20190204103605.271746870@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jacob Wen [ Upstream commit 4522a70db7aa5e77526a4079628578599821b193 ] Use pskb_may_pull() to make sure the optional fields are in skb linear parts, so we can safely read them later. It's easy to reproduce the issue with a net driver that supports paged skb data. Just create a L2TPv3 over IP tunnel and then generates some network traffic. Once reproduced, rx err in /sys/kernel/debug/l2tp/tunnels will increase. Changes in v4: 1. s/l2tp_v3_pull_opt/l2tp_v3_ensure_opt_in_linear/ 2. s/tunnel->version != L2TP_HDR_VER_2/tunnel->version == L2TP_HDR_VER_3/ 3. Add 'Fixes' in commit messages. Changes in v3: 1. To keep consistency, move the code out of l2tp_recv_common. 2. Use "net" instead of "net-next", since this is a bug fix. Changes in v2: 1. Only fix L2TPv3 to make code simple. To fix both L2TPv3 and L2TPv2, we'd better refactor l2tp_recv_common. It's complicated to do so. 2. Reloading pointers after pskb_may_pull Fixes: f7faffa3ff8e ("l2tp: Add L2TPv3 protocol support") Fixes: 0d76751fad77 ("l2tp: Add L2TPv3 IP encapsulation (no UDP) support") Fixes: a32e0eec7042 ("l2tp: introduce L2TPv3 IP encapsulation support for IPv6") Signed-off-by: Jacob Wen Acked-by: Guillaume Nault Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/l2tp/l2tp_core.c | 4 ++++ net/l2tp/l2tp_core.h | 20 ++++++++++++++++++++ net/l2tp/l2tp_ip.c | 3 +++ net/l2tp/l2tp_ip6.c | 3 +++ 4 files changed, 30 insertions(+) --- a/net/l2tp/l2tp_core.c +++ b/net/l2tp/l2tp_core.c @@ -1020,6 +1020,10 @@ static int l2tp_udp_recv_core(struct l2t goto error; } + if (tunnel->version == L2TP_HDR_VER_3 && + l2tp_v3_ensure_opt_in_linear(session, skb, &ptr, &optr)) + goto error; + l2tp_recv_common(session, skb, ptr, optr, hdrflags, length, payload_hook); l2tp_session_dec_refcount(session); --- a/net/l2tp/l2tp_core.h +++ b/net/l2tp/l2tp_core.h @@ -325,6 +325,26 @@ static inline int l2tp_get_l2specific_le } } +static inline int l2tp_v3_ensure_opt_in_linear(struct l2tp_session *session, struct sk_buff *skb, + unsigned char **ptr, unsigned char **optr) +{ + int opt_len = session->peer_cookie_len + l2tp_get_l2specific_len(session); + + if (opt_len > 0) { + int off = *ptr - *optr; + + if (!pskb_may_pull(skb, off + opt_len)) + return -1; + + if (skb->data != *optr) { + *optr = skb->data; + *ptr = skb->data + off; + } + } + + return 0; +} + #define l2tp_printk(ptr, type, func, fmt, ...) \ do { \ if (((ptr)->debug) & (type)) \ --- a/net/l2tp/l2tp_ip.c +++ b/net/l2tp/l2tp_ip.c @@ -157,6 +157,9 @@ static int l2tp_ip_recv(struct sk_buff * print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, ptr, length); } + if (l2tp_v3_ensure_opt_in_linear(session, skb, &ptr, &optr)) + goto discard_sess; + l2tp_recv_common(session, skb, ptr, optr, 0, skb->len, tunnel->recv_payload_hook); l2tp_session_dec_refcount(session); --- a/net/l2tp/l2tp_ip6.c +++ b/net/l2tp/l2tp_ip6.c @@ -169,6 +169,9 @@ static int l2tp_ip6_recv(struct sk_buff print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, ptr, length); } + if (l2tp_v3_ensure_opt_in_linear(session, skb, &ptr, &optr)) + goto discard_sess; + l2tp_recv_common(session, skb, ptr, optr, 0, skb->len, tunnel->recv_payload_hook); l2tp_session_dec_refcount(session);