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=-5.2 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS, URIBL_BLOCKED,USER_AGENT_MUTT 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 0A6B8C43387 for ; Fri, 14 Dec 2018 18:30:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 479B6206C2 for ; Fri, 14 Dec 2018 18:30:49 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=apple.com header.i=@apple.com header.b="QqkuztJA" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730512AbeLNSar (ORCPT ); Fri, 14 Dec 2018 13:30:47 -0500 Received: from ma1-aaemail-dr-lapp03.apple.com ([17.171.2.72]:43894 "EHLO ma1-aaemail-dr-lapp03.apple.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729341AbeLNSaq (ORCPT ); Fri, 14 Dec 2018 13:30:46 -0500 X-Greylist: delayed 9491 seconds by postgrey-1.27 at vger.kernel.org; Fri, 14 Dec 2018 13:30:45 EST Received: from pps.filterd (ma1-aaemail-dr-lapp03.apple.com [127.0.0.1]) by ma1-aaemail-dr-lapp03.apple.com (8.16.0.27/8.16.0.27) with SMTP id wBEFkfkG020004; Fri, 14 Dec 2018 07:52:27 -0800 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=apple.com; h=mime-version : content-transfer-encoding : content-type : sender : date : from : to : cc : subject : message-id : references : in-reply-to; s=20180706; bh=Y8FF0AqsADmzHN3tUbUD/5liozAynnbJWpiTPUipNuo=; b=QqkuztJAooJ2s2NMK8MTuXgV+4Pca+BR60hajtvqc9CEPLH79pr5ytW8nC6SnXK5v4Rj Ne603/6SpGcNeZXgaOpQoRrgthxrxE1dwdiMVtNVYTpG83Z9G9ozB3kR5cdC5xP2d72w UTLiIyyoixF6xF2f7SdpnmHjFqxjcit4WkQ0Ehl1sU3jI2VYPvFEjWIXW/zoXx5p/HAo H05XJBo5nsoXIKEioCygB8gYT20C9e78yJL76Q/GT411UOOaCWfA/3qulMHrcu4GTLG6 vGTYtGNufWcaJ/rWJ4rcVLuMmkbNEl7Ji2Li4tbavK1pW4GYmyI0a363YXQmdAbkp8Du Og== Received: from ma1-mtap-s03.corp.apple.com (ma1-mtap-s03.corp.apple.com [17.40.76.7]) by ma1-aaemail-dr-lapp03.apple.com with ESMTP id 2pa3b4xghh-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NO); Fri, 14 Dec 2018 07:52:27 -0800 MIME-version: 1.0 Content-transfer-encoding: 7BIT Content-disposition: inline Content-type: text/plain; CHARSET=US-ASCII Received: from nwk-mmpp-sz10.apple.com (nwk-mmpp-sz10.apple.com [17.128.115.122]) by ma1-mtap-s03.corp.apple.com (Oracle Communications Messaging Server 8.0.2.3.20181024 64bit (built Oct 24 2018)) with ESMTPS id <0PJQ0078ZHFFQ980@ma1-mtap-s03.corp.apple.com>; Fri, 14 Dec 2018 07:52:27 -0800 (PST) Received: from process_viserion-daemon.nwk-mmpp-sz10.apple.com by nwk-mmpp-sz10.apple.com (Oracle Communications Messaging Server 8.0.2.3.20181024 64bit (built Oct 24 2018)) id <0PJQ00H00GWRZ600@nwk-mmpp-sz10.apple.com>; Fri, 14 Dec 2018 07:52:27 -0800 (PST) X-Va-A: X-Va-T-CD: 3292cb8df71769077a8e6c728895331c X-Va-E-CD: 4323c9cb7650976afee1876783f7d85e X-Va-R-CD: d885efb23def6dc3d7fbf3a036d898ad X-Va-CD: 0 X-Va-ID: 564623da-b79c-4b90-8acc-c48569a9b278 X-V-A: X-V-T-CD: e3ce1f560f53d3ee7d03c9da4c45394f X-V-E-CD: 4323c9cb7650976afee1876783f7d85e X-V-R-CD: d885efb23def6dc3d7fbf3a036d898ad X-V-CD: 0 X-V-ID: fd7be8f1-d2da-4fe7-97a6-098fde22d970 Received: from process_milters-daemon.nwk-mmpp-sz10.apple.com by nwk-mmpp-sz10.apple.com (Oracle Communications Messaging Server 8.0.2.3.20181024 64bit (built Oct 24 2018)) id <0PJQ00J00H32SS00@nwk-mmpp-sz10.apple.com>; Fri, 14 Dec 2018 07:52:26 -0800 (PST) X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2018-12-14_08:,, signatures=0 Received: from localhost ([17.234.103.59]) by nwk-mmpp-sz10.apple.com (Oracle Communications Messaging Server 8.0.2.3.20181024 64bit (built Oct 24 2018)) with ESMTPSA id <0PJQ006ZXHFE8340@nwk-mmpp-sz10.apple.com>; Fri, 14 Dec 2018 07:52:26 -0800 (PST) Date: Fri, 14 Dec 2018 07:52:26 -0800 From: Christoph Paasch To: Greg Kroah-Hartman Cc: linux-kernel@vger.kernel.org, stable@vger.kernel.org, Prashant Bhole , Tyler Hicks , Eric Dumazet , Eric Dumazet , "David S. Miller" Subject: Re: [PATCH 4.14 09/89] net: Prevent invalid access to skb->prev in __qdisc_drop_all Message-id: <20181214155226.GJ41383@MacBook-Pro-19.local> References: <20181214115729.658859279@linuxfoundation.org> <20181214115730.135586551@linuxfoundation.org> In-reply-to: <20181214115730.135586551@linuxfoundation.org> User-Agent: Mutt/1.9.4 (2018-02-28) X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2018-12-14_08:,, signatures=0 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello Greg, On 14/12/18 - 12:59:22, Greg Kroah-Hartman wrote: > 4.14-stable review patch. If anyone has any objections, please let me know. > > ------------------ > > From: Christoph Paasch > > [ Upstream commit 9410d386d0a829ace9558336263086c2fbbe8aed ] > > __qdisc_drop_all() accesses skb->prev to get to the tail of the > segment-list. > > With commit 68d2f84a1368 ("net: gro: properly remove skb from list") > the skb-list handling has been changed to set skb->next to NULL and set > the list-poison on skb->prev. > > With that change, __qdisc_drop_all() will panic when it tries to > dereference skb->prev. > > Since commit 992cba7e276d ("net: Add and use skb_list_del_init().") > __list_del_entry is used, leaving skb->prev unchanged (thus, > pointing to the list-head if it's the first skb of the list). > This will make __qdisc_drop_all modify the next-pointer of the list-head > and result in a panic later on: > > [ 34.501053] general protection fault: 0000 [#1] SMP KASAN PTI > [ 34.501968] CPU: 2 PID: 0 Comm: swapper/2 Not tainted 4.20.0-rc2.mptcp #108 > [ 34.502887] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 0.5.1 01/01/2011 > [ 34.504074] RIP: 0010:dev_gro_receive+0x343/0x1f90 > [ 34.504751] Code: e0 48 c1 e8 03 42 80 3c 30 00 0f 85 4a 1c 00 00 4d 8b 24 24 4c 39 65 d0 0f 84 0a 04 00 00 49 8d 7c 24 38 48 89 f8 48 c1 e8 03 <42> 0f b6 04 30 84 c0 74 08 3c 04 > [ 34.507060] RSP: 0018:ffff8883af507930 EFLAGS: 00010202 > [ 34.507761] RAX: 0000000000000007 RBX: ffff8883970b2c80 RCX: 1ffff11072e165a6 > [ 34.508640] RDX: 1ffff11075867008 RSI: ffff8883ac338040 RDI: 0000000000000038 > [ 34.509493] RBP: ffff8883af5079d0 R08: ffff8883970b2d40 R09: 0000000000000062 > [ 34.510346] R10: 0000000000000034 R11: 0000000000000000 R12: 0000000000000000 > [ 34.511215] R13: 0000000000000000 R14: dffffc0000000000 R15: ffff8883ac338008 > [ 34.512082] FS: 0000000000000000(0000) GS:ffff8883af500000(0000) knlGS:0000000000000000 > [ 34.513036] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > [ 34.513741] CR2: 000055ccc3e9d020 CR3: 00000003abf32000 CR4: 00000000000006e0 > [ 34.514593] Call Trace: > [ 34.514893] > [ 34.515157] napi_gro_receive+0x93/0x150 > [ 34.515632] receive_buf+0x893/0x3700 > [ 34.516094] ? __netif_receive_skb+0x1f/0x1a0 > [ 34.516629] ? virtnet_probe+0x1b40/0x1b40 > [ 34.517153] ? __stable_node_chain+0x4d0/0x850 > [ 34.517684] ? kfree+0x9a/0x180 > [ 34.518067] ? __kasan_slab_free+0x171/0x190 > [ 34.518582] ? detach_buf+0x1df/0x650 > [ 34.519061] ? lapic_next_event+0x5a/0x90 > [ 34.519539] ? virtqueue_get_buf_ctx+0x280/0x7f0 > [ 34.520093] virtnet_poll+0x2df/0xd60 > [ 34.520533] ? receive_buf+0x3700/0x3700 > [ 34.521027] ? qdisc_watchdog_schedule_ns+0xd5/0x140 > [ 34.521631] ? htb_dequeue+0x1817/0x25f0 > [ 34.522107] ? sch_direct_xmit+0x142/0xf30 > [ 34.522595] ? virtqueue_napi_schedule+0x26/0x30 > [ 34.523155] net_rx_action+0x2f6/0xc50 > [ 34.523601] ? napi_complete_done+0x2f0/0x2f0 > [ 34.524126] ? kasan_check_read+0x11/0x20 > [ 34.524608] ? _raw_spin_lock+0x7d/0xd0 > [ 34.525070] ? _raw_spin_lock_bh+0xd0/0xd0 > [ 34.525563] ? kvm_guest_apic_eoi_write+0x6b/0x80 > [ 34.526130] ? apic_ack_irq+0x9e/0xe0 > [ 34.526567] __do_softirq+0x188/0x4b5 > [ 34.527015] irq_exit+0x151/0x180 > [ 34.527417] do_IRQ+0xdb/0x150 > [ 34.527783] common_interrupt+0xf/0xf > [ 34.528223] > > This patch makes sure that skb->prev is set to NULL when entering > netem_enqueue. > > Cc: Prashant Bhole > Cc: Tyler Hicks > Cc: Eric Dumazet > Fixes: 68d2f84a1368 ("net: gro: properly remove skb from list") > Suggested-by: Eric Dumazet > Signed-off-by: Christoph Paasch > Reviewed-by: Eric Dumazet > Signed-off-by: David S. Miller > Signed-off-by: Greg Kroah-Hartman I don't think this patch needs to be backported. I haven't hit this panic on v4.14.x (although, I only have been using v4.14.79 for now - not yet the latest one). And the commits that seem to have introduced the issue haven't been backported either AFAICS. That being said, I don't think a backport would cause any side-effects. Or have you seen reports of this panic in the stable branches? (same for the other stable branches v4.4,... - cfr., the other mails regarding this patch here) Cheers, Christoph > --- > net/sched/sch_netem.c | 3 +++ > 1 file changed, 3 insertions(+) > > --- a/net/sched/sch_netem.c > +++ b/net/sched/sch_netem.c > @@ -436,6 +436,9 @@ static int netem_enqueue(struct sk_buff > int count = 1; > int rc = NET_XMIT_SUCCESS; > > + /* Do not fool qdisc_drop_all() */ > + skb->prev = NULL; > + > /* Random duplication */ > if (q->duplicate && q->duplicate >= get_crandom(&q->dup_cor)) > ++count; > >