From patchwork Fri Nov 30 00:01:04 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christoph Paasch X-Patchwork-Id: 1005741 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming-netdev@ozlabs.org Delivered-To: patchwork-incoming-netdev@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=netdev-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=fail (p=none dis=none) header.from=apple.com Authentication-Results: ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=apple.com header.i=@apple.com header.b="WEHpcmfy"; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 435ZLw1sbmz9sB7 for ; Fri, 30 Nov 2018 11:02:00 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727112AbeK3LJQ (ORCPT ); Fri, 30 Nov 2018 06:09:16 -0500 Received: from nwk-aaemail-lapp01.apple.com ([17.151.62.66]:50528 "EHLO nwk-aaemail-lapp01.apple.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726446AbeK3LJP (ORCPT ); Fri, 30 Nov 2018 06:09:15 -0500 Received: from pps.filterd (nwk-aaemail-lapp01.apple.com [127.0.0.1]) by nwk-aaemail-lapp01.apple.com (8.16.0.22/8.16.0.22) with SMTP id wATNuwpA064859; Thu, 29 Nov 2018 16:01:52 -0800 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=apple.com; h=content-transfer-encoding : sender : from : to : cc : subject : date : message-id; s=20180706; bh=2jrLQTLPK5vQihtgm2fy+3LF+bGlHavuVS+QQa0gE0I=; b=WEHpcmfyuDoiTun/Dg2EynQUAV+xWvqTOKQHQ9ut+Txq1ygr2zfIIeXYyiwiTPmcs69W Uk/hphnyDB1vNf0xOU/U6zd5VohEwoyfEkB6thNRxeMiHGHlAt4MeQ+QYsdeJagJ5EZh NYchS2maOrawnpZZL615Gb3DTSdgnXoHwBE0uFucGEfccPGA24XkzuJ+cgFa+br70pl8 1IaDeSxbQ+vYSsNDdi5+SiSyCLMTaUxLIjaoEUa7CtPQhlfg8g/pQbDtOVJmgg3Hpl7+ wtcIcKaJx0IV8eLtuOfhJSB3loiSOTWmz2QcZfIwk/X/LSCYuYxNXT4Yo43msjhAr+VR hw== Received: from mr2-mtap-s03.rno.apple.com (mr2-mtap-s03.rno.apple.com [17.179.226.135]) by nwk-aaemail-lapp01.apple.com with ESMTP id 2p0tre2f49-2 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NO); Thu, 29 Nov 2018 16:01:52 -0800 Content-transfer-encoding: 7BIT Received: from nwk-mmpp-sz10.apple.com (nwk-mmpp-sz10.apple.com [17.128.115.122]) by mr2-mtap-s03.rno.apple.com (Oracle Communications Messaging Server 8.0.2.3.20180614 64bit (built Jun 14 2018)) with ESMTPS id <0PIZ005RLC31LV20@mr2-mtap-s03.rno.apple.com>; Thu, 29 Nov 2018 16:01:49 -0800 (PST) Received: from process_viserion-daemon.nwk-mmpp-sz10.apple.com by nwk-mmpp-sz10.apple.com (Oracle Communications Messaging Server 8.0.2.3.20180614 64bit (built Jun 14 2018)) id <0PIZ00B00BHGHC00@nwk-mmpp-sz10.apple.com>; Thu, 29 Nov 2018 16:01:49 -0800 (PST) X-Va-A: X-Va-T-CD: 3261cd830d760c0410952f995736816b X-Va-E-CD: 59a7d5749c661e42c6e1747d0ca998f0 X-Va-R-CD: 0788a5bd73242755523464b869485e28 X-Va-CD: 0 X-Va-ID: 52d3beac-7007-4bcc-ae03-f34f929b457e X-V-A: X-V-T-CD: 9282bafb218900537fab2921e7776c7e X-V-E-CD: 59a7d5749c661e42c6e1747d0ca998f0 X-V-R-CD: 0788a5bd73242755523464b869485e28 X-V-CD: 0 X-V-ID: 3bffd3f6-df22-4911-b9f8-fe2ac279bd90 Received: from process_milters-daemon.nwk-mmpp-sz10.apple.com by nwk-mmpp-sz10.apple.com (Oracle Communications Messaging Server 8.0.2.3.20180614 64bit (built Jun 14 2018)) id <0PIZ00L00C2N2E00@nwk-mmpp-sz10.apple.com>; Thu, 29 Nov 2018 16:01:48 -0800 (PST) X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2018-11-29_14:,, signatures=0 Received: from localhost ([17.149.208.87]) by nwk-mmpp-sz10.apple.com (Oracle Communications Messaging Server 8.0.2.3.20180614 64bit (built Jun 14 2018)) with ESMTPSA id <0PIZ00FQNC2ZNGE0@nwk-mmpp-sz10.apple.com>; Thu, 29 Nov 2018 16:01:47 -0800 (PST) From: Christoph Paasch To: David Miller Cc: netdev@vger.kernel.org, Prashant Bhole , Tyler Hicks , Eric Dumazet Subject: [PATCH v2 net] net: Prevent invalid access to skb->prev in __qdisc_drop_all Date: Thu, 29 Nov 2018 16:01:04 -0800 Message-id: <20181130000104.13213-1-cpaasch@apple.com> X-Mailer: git-send-email 2.16.2 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:, , definitions=2018-11-29_14:, , signatures=0 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org __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 --- Notes: v2: - Set skb->prev to NULL in netem_enqueue instead. net/sched/sch_netem.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/net/sched/sch_netem.c b/net/sched/sch_netem.c index 2c38e3d07924..22cd46a60057 100644 --- a/net/sched/sch_netem.c +++ b/net/sched/sch_netem.c @@ -431,6 +431,9 @@ static int netem_enqueue(struct sk_buff *skb, struct Qdisc *sch, 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;