From patchwork Mon Feb 12 17:49:39 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paolo Abeni X-Patchwork-Id: 872236 X-Patchwork-Delegate: pablo@netfilter.org Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=netfilter-devel-owner@vger.kernel.org; receiver=) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 3zgCrp2CCPz9t39 for ; Tue, 13 Feb 2018 04:51:06 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753303AbeBLRvC (ORCPT ); Mon, 12 Feb 2018 12:51:02 -0500 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:43874 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751268AbeBLRvB (ORCPT ); Mon, 12 Feb 2018 12:51:01 -0500 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.rdu2.redhat.com [10.11.54.6]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id B36238182D28; Mon, 12 Feb 2018 17:51:00 +0000 (UTC) Received: from localhost.localdomain.com (unknown [10.32.181.99]) by smtp.corp.redhat.com (Postfix) with ESMTP id 9C2902166BAE; Mon, 12 Feb 2018 17:50:59 +0000 (UTC) From: Paolo Abeni To: netdev@vger.kernel.org Cc: Pablo Neira Ayuso , Florian Westphal , netfilter-devel@vger.kernel.org, "David S. Miller" , syzkaller-bugs@googlegroups.com, Adam Nielsen Subject: [PATCH net v2] netfilter: x_tables: fix missing timer initialization in xt_LED Date: Mon, 12 Feb 2018 18:49:39 +0100 Message-Id: <2a65c93c132cb8b7d0f12a9756f34aa3199e5401.1518456437.git.pabeni@redhat.com> X-Scanned-By: MIMEDefang 2.78 on 10.11.54.6 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.8]); Mon, 12 Feb 2018 17:51:00 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.8]); Mon, 12 Feb 2018 17:51:00 +0000 (UTC) for IP:'10.11.54.6' DOMAIN:'int-mx06.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'pabeni@redhat.com' RCPT:'' Sender: netfilter-devel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netfilter-devel@vger.kernel.org syzbot reported that xt_LED may try to use the ledinternal->timer without previously initializing it: ------------[ cut here ]------------ kernel BUG at kernel/time/timer.c:958! invalid opcode: 0000 [#1] SMP KASAN Dumping ftrace buffer: (ftrace buffer empty) Modules linked in: CPU: 1 PID: 1826 Comm: kworker/1:2 Not tainted 4.15.0+ #306 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: ipv6_addrconf addrconf_dad_work RIP: 0010:__mod_timer kernel/time/timer.c:958 [inline] RIP: 0010:mod_timer+0x7d6/0x13c0 kernel/time/timer.c:1102 RSP: 0018:ffff8801d24fe9f8 EFLAGS: 00010293 RAX: ffff8801d25246c0 RBX: ffff8801aec6cb50 RCX: ffffffff816052c6 RDX: 0000000000000000 RSI: 00000000fffbd14b RDI: ffff8801aec6cb68 RBP: ffff8801d24fec98 R08: 0000000000000000 R09: 1ffff1003a49fd6c R10: ffff8801d24feb28 R11: 0000000000000005 R12: dffffc0000000000 R13: ffff8801d24fec70 R14: 00000000fffbd14b R15: ffff8801af608f90 FS: 0000000000000000(0000) GS:ffff8801db500000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000206d6fd0 CR3: 0000000006a22001 CR4: 00000000001606e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: led_tg+0x1db/0x2e0 net/netfilter/xt_LED.c:75 ip6t_do_table+0xc2a/0x1a30 net/ipv6/netfilter/ip6_tables.c:365 ip6table_raw_hook+0x65/0x80 net/ipv6/netfilter/ip6table_raw.c:42 nf_hook_entry_hookfn include/linux/netfilter.h:120 [inline] nf_hook_slow+0xba/0x1a0 net/netfilter/core.c:483 nf_hook.constprop.27+0x3f6/0x830 include/linux/netfilter.h:243 NF_HOOK include/linux/netfilter.h:286 [inline] ndisc_send_skb+0xa51/0x1370 net/ipv6/ndisc.c:491 ndisc_send_ns+0x38a/0x870 net/ipv6/ndisc.c:633 addrconf_dad_work+0xb9e/0x1320 net/ipv6/addrconf.c:4008 process_one_work+0xbbf/0x1af0 kernel/workqueue.c:2113 worker_thread+0x223/0x1990 kernel/workqueue.c:2247 kthread+0x33c/0x400 kernel/kthread.c:238 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:429 Code: 85 2a 0b 00 00 4d 8b 3c 24 4d 85 ff 75 9f 4c 8b bd 60 fd ff ff e8 bb 57 10 00 65 ff 0d 94 9a a1 7e e9 d9 fc ff ff e8 aa 57 10 00 <0f> 0b e8 a3 57 10 00 e9 14 fb ff ff e8 99 57 10 00 4c 89 bd 70 RIP: __mod_timer kernel/time/timer.c:958 [inline] RSP: ffff8801d24fe9f8 RIP: mod_timer+0x7d6/0x13c0 kernel/time/timer.c:1102 RSP: ffff8801d24fe9f8 ---[ end trace f661ab06f5dd8b3d ]--- The ledinternal struct can be shared between several different xt_LED targets, but the related timer is currently initialized only if the first target requires it. Fix it by unconditionally initializing the timer struct. v1 -> v2: call del_timer_sync() unconditionally, too. Fixes: 268cb38e1802 ("netfilter: x_tables: add LED trigger target") Reported-by: syzbot+10c98dc5725c6c8fc7fb@syzkaller.appspotmail.com Signed-off-by: Paolo Abeni --- net/netfilter/xt_LED.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/net/netfilter/xt_LED.c b/net/netfilter/xt_LED.c index 1dcad893df78..0fb2133165aa 100644 --- a/net/netfilter/xt_LED.c +++ b/net/netfilter/xt_LED.c @@ -142,9 +142,10 @@ static int led_tg_check(const struct xt_tgchk_param *par) goto exit_alloc; } - /* See if we need to set up a timer */ - if (ledinfo->delay > 0) - timer_setup(&ledinternal->timer, led_timeout_callback, 0); + /* Since the letinternal timer can be shared between multiple targets, + * always set it up, even if the current target does not need it + */ + timer_setup(&ledinternal->timer, led_timeout_callback, 0); list_add_tail(&ledinternal->list, &xt_led_triggers); @@ -181,8 +182,7 @@ static void led_tg_destroy(const struct xt_tgdtor_param *par) list_del(&ledinternal->list); - if (ledinfo->delay > 0) - del_timer_sync(&ledinternal->timer); + del_timer_sync(&ledinternal->timer); led_trigger_unregister(&ledinternal->netfilter_led_trigger);