From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S966158Ab2DLVll (ORCPT ); Thu, 12 Apr 2012 17:41:41 -0400 Received: from kirsty.vergenet.net ([202.4.237.240]:38521 "EHLO kirsty.vergenet.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S966137Ab2DLVld (ORCPT ); Thu, 12 Apr 2012 17:41:33 -0400 Date: Fri, 13 Apr 2012 06:41:28 +0900 From: Simon Horman To: Pablo Neira Ayuso Cc: Sasha Levin , wensong@linux-vs.org, ja@ssi.bg, kaber@trash.net, davem@davemloft.net, davej@redhat.com, netdev@vger.kernel.org, lvs-devel@vger.kernel.org, netfilter-devel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] netfilter: ipvs: Verify that IP_VS protocol has been registered Message-ID: <20120412214127.GA18687@verge.net.au> References: <1333668273-8873-1-git-send-email-levinsasha928@gmail.com> <20120411232243.GB7038@1984> <20120411234628.GA7253@1984> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20120411234628.GA7253@1984> Organisation: Horms Solutions Ltd. User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Apr 12, 2012 at 01:46:28AM +0200, Pablo Neira Ayuso wrote: > On Thu, Apr 12, 2012 at 01:22:43AM +0200, Pablo Neira Ayuso wrote: > > On Thu, Apr 05, 2012 at 07:24:33PM -0400, Sasha Levin wrote: > > > The registration of a protocol might fail, there were no checks > > > and all registrations were assumed to be correct. This lead to > > > NULL ptr dereferences when apps tried registering. > > > > > > For example: > > > > > > [ 1293.226051] BUG: unable to handle kernel NULL pointer dereference at 0000000000000018 > > > [ 1293.227038] IP: [] tcp_register_app+0x60/0xb0 > > > [ 1293.227038] PGD 391de067 PUD 6c20b067 PMD 0 > > > [ 1293.227038] Oops: 0000 [#1] PREEMPT SMP > > > [ 1293.227038] CPU 1 > > > [ 1293.227038] Pid: 19609, comm: trinity Tainted: G W 3.4.0-rc1-next-20120405-sasha-dirty #57 > > > [ 1293.227038] RIP: 0010:[] [] tcp_register_app+0x60/0xb0 > > > [ 1293.227038] RSP: 0018:ffff880038c1dd18 EFLAGS: 00010286 > > > [ 1293.227038] RAX: ffffffffffffffc0 RBX: 0000000000001500 RCX: 0000000000010000 > > > [ 1293.227038] RDX: 0000000000000000 RSI: ffff88003a2d5888 RDI: 0000000000000282 > > > [ 1293.227038] RBP: ffff880038c1dd48 R08: 0000000000000000 R09: 0000000000000000 > > > [ 1293.227038] R10: 0000000000000000 R11: 0000000000000000 R12: ffff88003a2d5668 > > > [ 1293.227038] R13: ffff88003a2d5988 R14: ffff8800696a8ff8 R15: 0000000000000000 > > > [ 1293.227038] FS: 00007f01930d9700(0000) GS:ffff88007ce00000(0000) knlGS:0000000000000000 > > > [ 1293.227038] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b > > > [ 1293.227038] CR2: 0000000000000018 CR3: 0000000065dfc000 CR4: 00000000000406e0 > > > [ 1293.227038] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > > > [ 1293.227038] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 > > > [ 1293.227038] Process trinity (pid: 19609, threadinfo ffff880038c1c000, task ffff88002dc73000) > > > [ 1293.227038] Stack: > > > [ 1293.227038] ffff880038c1dd48 00000000fffffff4 ffff8800696aada0 ffff8800694f5580 > > > [ 1293.227038] ffffffff8369f1e0 0000000000001500 ffff880038c1dd98 ffffffff822a716b > > > [ 1293.227038] 0000000000000000 ffff8800696a8ff8 0000000000000015 ffff8800694f5580 > > > [ 1293.227038] Call Trace: > > > [ 1293.227038] [] ip_vs_app_inc_new+0xdb/0x180 > > > [ 1293.227038] [] register_ip_vs_app_inc+0x48/0x70 > > > [ 1293.227038] [] __ip_vs_ftp_init+0xba/0x140 > > > [ 1293.227038] [] ops_init+0x80/0x90 > > > [ 1293.227038] [] setup_net+0x5b/0xe0 > > > [ 1293.227038] [] copy_net_ns+0x76/0x100 > > > [ 1293.227038] [] create_new_namespaces+0xfb/0x190 > > > [ 1293.227038] [] unshare_nsproxy_namespaces+0x61/0x80 > > > [ 1293.227038] [] sys_unshare+0xff/0x290 > > > [ 1293.227038] [] ? trace_hardirqs_on_thunk+0x3a/0x3f > > > [ 1293.227038] [] system_call_fastpath+0x16/0x1b > > > [ 1293.227038] Code: 89 c7 e8 34 91 3b 00 89 de 66 c1 ee 04 31 de 83 e6 0f 48 83 c6 22 48 c1 e6 04 4a 8b 14 26 49 8d 34 34 48 8d 42 c0 48 39 d6 74 13 <66> 39 58 58 74 22 48 8b 48 40 48 8d 41 c0 48 39 ce 75 ed 49 8d > > > [ 1293.227038] RIP [] tcp_register_app+0x60/0xb0 > > > [ 1293.227038] RSP > > > [ 1293.227038] CR2: 0000000000000018 > > > [ 1293.379284] ---[ end trace 364ab40c7011a009 ]--- > > > [ 1293.381182] Kernel panic - not syncing: Fatal exception in interrupt > > > > > > Signed-off-by: Sasha Levin > > > --- > > > net/netfilter/ipvs/ip_vs_proto.c | 21 ++++++++++++++++----- > > > 1 files changed, 16 insertions(+), 5 deletions(-) > > > > > > diff --git a/net/netfilter/ipvs/ip_vs_proto.c b/net/netfilter/ipvs/ip_vs_proto.c > > > index f843a88..43893ba 100644 > > > --- a/net/netfilter/ipvs/ip_vs_proto.c > > > +++ b/net/netfilter/ipvs/ip_vs_proto.c > > > @@ -316,20 +316,31 @@ ip_vs_tcpudp_debug_packet(int af, struct ip_vs_protocol *pp, > > > */ > > > int __net_init ip_vs_protocol_net_init(struct net *net) > > > { > > > + int ret; > > > #ifdef CONFIG_IP_VS_PROTO_TCP > > > - register_ip_vs_proto_netns(net, &ip_vs_protocol_tcp); > > > + ret = register_ip_vs_proto_netns(net, &ip_vs_protocol_tcp); > > > + if (ret < 0) > > > + return ret; > > > #endif > > > #ifdef CONFIG_IP_VS_PROTO_UDP > > > - register_ip_vs_proto_netns(net, &ip_vs_protocol_udp); > > > + ret = register_ip_vs_proto_netns(net, &ip_vs_protocol_udp); > > > + if (ret < 0) > > > + return ret; > > > > If you return here, I think you'll leave things in inconsistent state, > > ie. the tcp protocol is registered. You have to unregister it before > > leaving. > > > > ret = register_ip_vs_proto_netns(net, &ip_vs_protocol_tcp); > ^^^ > sorry, I meant to say udp here. > > > if (ret < 0) > > goto err_tcp; > ^^^ > and here. > > > ... > > err_tcp: > > unregister_ip_vs_proto_netns(net, &ip_vs_protocol_tcp); > Thanks Pablo, I was thinking along those lines too. I'll send an updated patch.