From patchwork Sat May 28 00:36:51 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dave Jones X-Patchwork-Id: 97761 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id ADC89B6F90 for ; Sat, 28 May 2011 10:37:00 +1000 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757723Ab1E1Agz (ORCPT ); Fri, 27 May 2011 20:36:55 -0400 Received: from mx1.redhat.com ([209.132.183.28]:48321 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757560Ab1E1Agz (ORCPT ); Fri, 27 May 2011 20:36:55 -0400 Received: from int-mx10.intmail.prod.int.phx2.redhat.com (int-mx10.intmail.prod.int.phx2.redhat.com [10.5.11.23]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id p4S0asR5010829 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Fri, 27 May 2011 20:36:54 -0400 Received: from gelk.kernelslacker.org (ovpn-113-147.phx2.redhat.com [10.3.113.147]) by int-mx10.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id p4S0ar69021183 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Fri, 27 May 2011 20:36:53 -0400 Received: from gelk.kernelslacker.org (gelk [127.0.0.1]) by gelk.kernelslacker.org (8.14.4/8.14.4) with ESMTP id p4S0aq1u008441; Fri, 27 May 2011 20:36:52 -0400 Received: (from davej@localhost) by gelk.kernelslacker.org (8.14.4/8.14.4/Submit) id p4S0apMS008439; Fri, 27 May 2011 20:36:51 -0400 X-Authentication-Warning: gelk.kernelslacker.org: davej set sender to davej@redhat.com using -f Date: Fri, 27 May 2011 20:36:51 -0400 From: Dave Jones To: David Miller Cc: netdev@vger.kernel.org Subject: [PATCH] Use unsigned variables for packet lengths in ip[6]_queue. Message-ID: <20110528003651.GA8380@redhat.com> References: <20110420014221.GC26949@redhat.com> <20110419.204105.68144653.davem@davemloft.net> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20110419.204105.68144653.davem@davemloft.net> User-Agent: Mutt/1.5.21 (2010-09-15) X-Scanned-By: MIMEDefang 2.68 on 10.5.11.23 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Tue, Apr 19, 2011 at 08:41:05PM -0700, David Miller wrote: > From: Dave Jones > Date: Tue, 19 Apr 2011 21:42:22 -0400 > > > Not catastrophic, but ipqueue seems to be too trusting of what it gets > > passed from userspace, and passes it on down to the page allocator, > > where it will spew warnings if the page order is too high. > > > > __ipq_rcv_skb has several checks for lengths too small, but doesn't > > seem to have any for oversized ones. I'm not sure what the maximum > > we should check for is. I'll code up a diff if anyone has any ideas > > on a sane maximum. > > Maybe the thing to do is to simply pass __GFP_NOWARN to nlmsg_new() > in netlink_ack()? > > Anyone else have a better idea? So I went back to this today, and found something that doesn't look right. After adding some instrumentation, and re-running my tests, I found that the reason we were blowing up with enormous allocations was that we were passing down a nlmsglen's like -1061109568 Is there any reason for that to be signed ? The nlmsg_len entry of nlmsghdr is a u32, so I'm assuming this is a bug. With the patch below, I haven't been able to reproduce the problem, but I don't know if I've inadvertantly broken some other behaviour somewhere deeper in netlink where this is valid. Dave diff --git a/net/ipv4/netfilter/ip_queue.c b/net/ipv4/netfilter/ip_queue.c index d2c1311..f7f9bd7 100644 --- a/net/ipv4/netfilter/ip_queue.c +++ b/net/ipv4/netfilter/ip_queue.c @@ -402,7 +402,8 @@ ipq_dev_drop(int ifindex) static inline void __ipq_rcv_skb(struct sk_buff *skb) { - int status, type, pid, flags, nlmsglen, skblen; + int status, type, pid, flags; + unsigned int nlmsglen, skblen; struct nlmsghdr *nlh; skblen = skb->len; diff --git a/net/ipv6/netfilter/ip6_queue.c b/net/ipv6/netfilter/ip6_queue.c index 413ab07..065fe40 100644 --- a/net/ipv6/netfilter/ip6_queue.c +++ b/net/ipv6/netfilter/ip6_queue.c @@ -403,7 +403,8 @@ ipq_dev_drop(int ifindex) static inline void __ipq_rcv_skb(struct sk_buff *skb) { - int status, type, pid, flags, nlmsglen, skblen; + int status, type, pid, flags; + unsigned int nlmsglen, skblen; struct nlmsghdr *nlh; skblen = skb->len;