From patchwork Mon Apr 18 14:05:00 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Luis Henriques X-Patchwork-Id: 611749 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from huckleberry.canonical.com (huckleberry.canonical.com [91.189.94.19]) by ozlabs.org (Postfix) with ESMTP id 3qpVK63jGWz9t3l; Tue, 19 Apr 2016 00:05:14 +1000 (AEST) Received: from localhost ([127.0.0.1] helo=huckleberry.canonical.com) by huckleberry.canonical.com with esmtp (Exim 4.76) (envelope-from ) id 1as9nb-0004Hw-G8; Mon, 18 Apr 2016 14:05:11 +0000 Received: from youngberry.canonical.com ([91.189.89.112]) by huckleberry.canonical.com with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.76) (envelope-from ) id 1as9nS-0004Fb-Nr for kernel-team@lists.ubuntu.com; Mon, 18 Apr 2016 14:05:02 +0000 Received: from 1.general.henrix.uk.vpn ([10.172.192.212] helo=localhost) by youngberry.canonical.com with esmtpsa (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.76) (envelope-from ) id 1as9nS-0004Gs-2v for kernel-team@lists.ubuntu.com; Mon, 18 Apr 2016 14:05:02 +0000 From: Luis Henriques To: kernel-team@lists.ubuntu.com Subject: [PATCH 1/1] ipv4: Don't do expensive useless work during inetdev destroy. Date: Mon, 18 Apr 2016 15:05:00 +0100 Message-Id: <1460988300-17177-2-git-send-email-luis.henriques@canonical.com> In-Reply-To: <1460988300-17177-1-git-send-email-luis.henriques@canonical.com> References: <1460988300-17177-1-git-send-email-luis.henriques@canonical.com> X-BeenThere: kernel-team@lists.ubuntu.com X-Mailman-Version: 2.1.14 Precedence: list List-Id: Kernel team discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: kernel-team-bounces@lists.ubuntu.com Sender: kernel-team-bounces@lists.ubuntu.com From: "David S. Miller" When an inetdev is destroyed, every address assigned to the interface is removed. And in this scenerio we do two pointless things which can be very expensive if the number of assigned interfaces is large: 1) Address promotion. We are deleting all addresses, so there is no point in doing this. 2) A full nf conntrack table purge for every address. We only need to do this once, as is already caught by the existing masq_dev_notifier so masq_inet_event() can skip this. Reported-by: Solar Designer Signed-off-by: David S. Miller Tested-by: Cyrill Gorcunov (backported from commit fbd40ea0180a2d328c5adc61414dc8bab9335ce2) [ luis: file rename: nf_nat_masquerade_ipv4.c -> ipt_MASQUERADE.c ] CVE-2016-3156 BugLink: https://bugs.launchpad.net/bugs/1558847 Signed-off-by: Luis Henriques --- net/ipv4/devinet.c | 4 ++++ net/ipv4/fib_frontend.c | 4 ++++ net/ipv4/netfilter/ipt_MASQUERADE.c | 12 ++++++++++-- 3 files changed, 18 insertions(+), 2 deletions(-) diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c index 68447109000f..6678bebb82c8 100644 --- a/net/ipv4/devinet.c +++ b/net/ipv4/devinet.c @@ -328,6 +328,9 @@ static void __inet_del_ifa(struct in_device *in_dev, struct in_ifaddr **ifap, ASSERT_RTNL(); + if (in_dev->dead) + goto no_promotions; + /* 1. Deleting primary ifaddr forces deletion all secondaries * unless alias promotion is set **/ @@ -374,6 +377,7 @@ static void __inet_del_ifa(struct in_device *in_dev, struct in_ifaddr **ifap, fib_del_ifaddr(ifa, ifa1); } +no_promotions: /* 2. Unlink it */ *ifap = ifa1->ifa_next; diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c index c7539e22868b..4d4952129bc1 100644 --- a/net/ipv4/fib_frontend.c +++ b/net/ipv4/fib_frontend.c @@ -812,6 +812,9 @@ void fib_del_ifaddr(struct in_ifaddr *ifa, struct in_ifaddr *iprim) subnet = 1; } + if (in_dev->dead) + goto no_promotions; + /* Deletion is more complicated than add. * We should take care of not to delete too much :-) * @@ -887,6 +890,7 @@ void fib_del_ifaddr(struct in_ifaddr *ifa, struct in_ifaddr *iprim) } } +no_promotions: if (!(ok & BRD_OK)) fib_magic(RTM_DELROUTE, RTN_BROADCAST, ifa->ifa_broadcast, 32, prim); if (subnet && ifa->ifa_prefixlen < 31) { diff --git a/net/ipv4/netfilter/ipt_MASQUERADE.c b/net/ipv4/netfilter/ipt_MASQUERADE.c index 00352ce0f0de..3bc1c98aa2f0 100644 --- a/net/ipv4/netfilter/ipt_MASQUERADE.c +++ b/net/ipv4/netfilter/ipt_MASQUERADE.c @@ -128,10 +128,18 @@ static int masq_inet_event(struct notifier_block *this, unsigned long event, void *ptr) { - struct net_device *dev = ((struct in_ifaddr *)ptr)->ifa_dev->dev; + struct in_device *idev = ((struct in_ifaddr *)ptr)->ifa_dev; struct netdev_notifier_info info; - netdev_notifier_info_init(&info, dev); + /* The masq_dev_notifier will catch the case of the device going + * down. So if the inetdev is dead and being destroyed we have + * no work to do. Otherwise this is an individual address removal + * and we have to perform the flush. + */ + if (idev->dead) + return NOTIFY_DONE; + + netdev_notifier_info_init(&info, idev->dev); return masq_device_event(this, event, &info); }