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=-10.6 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 3222AC43612 for ; Mon, 7 Jan 2019 13:05:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 033E021855 for ; Mon, 7 Jan 2019 13:05:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1546866304; bh=iVflgGeAEQORWoZ+mVg9ugsvhNb/wcj+Kw+0RkydHHY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=dgC/ikgmWR28kx/+sm2DqZ7Jd1lkEIyDjA4TJaVyh3W57usvL8X6NeDdczwaYPhgt XkgXGQhMaMsH1r1eN72k4jnV+cGSSLpeuONPIQE92dIhhrVrdH5D1T5rRi7vHJHQPd audHHsEi86/AbcetS/FF+mtbLH3NLVCU5mBgRqMo= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731410AbfAGNFC (ORCPT ); Mon, 7 Jan 2019 08:05:02 -0500 Received: from mail.kernel.org ([198.145.29.99]:52742 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731401AbfAGNFC (ORCPT ); Mon, 7 Jan 2019 08:05:02 -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 72C38217D4; Mon, 7 Jan 2019 13:05:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1546866301; bh=iVflgGeAEQORWoZ+mVg9ugsvhNb/wcj+Kw+0RkydHHY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=dlFNBUY2MtMw9ivG7saHK/1JxHIspGHcZ1uvoiSmEw6/0vSR14qhtN3yKutWBlfRr 7OYzVavYBnHDRX2sz6z0RqpePISfH1lfvO69TVXo8d/hRByLZUUzYwxqqCvwNNUo0J E9DtB62RNIcc3RvtolOUpEQGhMZtwzi3qzw5Ql2M= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Michal Kubecek , "David S. Miller" Subject: [PATCH 4.9 12/71] net: ipv4: do not handle duplicate fragments as overlapping Date: Mon, 7 Jan 2019 13:32:41 +0100 Message-Id: <20190107105331.390451112@linuxfoundation.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190107105330.280153213@linuxfoundation.org> References: <20190107105330.280153213@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: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Michal Kubecek [ Upstream commit ade446403bfb79d3528d56071a84b15351a139ad ] Since commit 7969e5c40dfd ("ip: discard IPv4 datagrams with overlapping segments.") IPv4 reassembly code drops the whole queue whenever an overlapping fragment is received. However, the test is written in a way which detects duplicate fragments as overlapping so that in environments with many duplicate packets, fragmented packets may be undeliverable. Add an extra test and for (potentially) duplicate fragment, only drop the new fragment rather than the whole queue. Only starting offset and length are checked, not the contents of the fragments as that would be too expensive. For similar reason, linear list ("run") of a rbtree node is not iterated, we only check if the new fragment is a subset of the interval covered by existing consecutive fragments. v2: instead of an exact check iterating through linear list of an rbtree node, only check if the new fragment is subset of the "run" (suggested by Eric Dumazet) Fixes: 7969e5c40dfd ("ip: discard IPv4 datagrams with overlapping segments.") Signed-off-by: Michal Kubecek Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/ipv4/ip_fragment.c | 18 ++++++++++++------ 1 file changed, 12 insertions(+), 6 deletions(-) --- a/net/ipv4/ip_fragment.c +++ b/net/ipv4/ip_fragment.c @@ -345,10 +345,10 @@ static int ip_frag_queue(struct ipq *qp, struct net *net = container_of(qp->q.net, struct net, ipv4.frags); struct rb_node **rbn, *parent; struct sk_buff *skb1, *prev_tail; + int ihl, end, skb1_run_end; struct net_device *dev; unsigned int fragsize; int flags, offset; - int ihl, end; int err = -ENOENT; u8 ecn; @@ -418,7 +418,9 @@ static int ip_frag_queue(struct ipq *qp, * overlapping fragment, the entire datagram (and any constituent * fragments) MUST be silently discarded. * - * We do the same here for IPv4 (and increment an snmp counter). + * We do the same here for IPv4 (and increment an snmp counter) but + * we do not want to drop the whole queue in response to a duplicate + * fragment. */ /* Find out where to put this fragment. */ @@ -442,13 +444,17 @@ static int ip_frag_queue(struct ipq *qp, do { parent = *rbn; skb1 = rb_to_skb(parent); + skb1_run_end = skb1->ip_defrag_offset + + FRAG_CB(skb1)->frag_run_len; if (end <= skb1->ip_defrag_offset) rbn = &parent->rb_left; - else if (offset >= skb1->ip_defrag_offset + - FRAG_CB(skb1)->frag_run_len) + else if (offset >= skb1_run_end) rbn = &parent->rb_right; - else /* Found an overlap with skb1. */ - goto discard_qp; + else if (offset >= skb1->ip_defrag_offset && + end <= skb1_run_end) + goto err; /* No new data, potential duplicate */ + else + goto discard_qp; /* Found an overlap */ } while (*rbn); /* Here we have parent properly set, and rbn pointing to * one of its NULL left/right children. Insert skb.