From patchwork Thu Nov 29 22:27:12 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christoph Paasch X-Patchwork-Id: 1005694 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="OMlyIIVK"; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 435XGH37B6z9s5c for ; Fri, 30 Nov 2018 09:27:51 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726403AbeK3Jeu (ORCPT ); Fri, 30 Nov 2018 04:34:50 -0500 Received: from nwk-aaemail-lapp03.apple.com ([17.151.62.68]:45502 "EHLO nwk-aaemail-lapp03.apple.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726374AbeK3Jeu (ORCPT ); Fri, 30 Nov 2018 04:34:50 -0500 Received: from pps.filterd (nwk-aaemail-lapp03.apple.com [127.0.0.1]) by nwk-aaemail-lapp03.apple.com (8.16.0.22/8.16.0.22) with SMTP id wATMLj4R044221; Thu, 29 Nov 2018 14:27:43 -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=Sjv5xOxOj4QnPvhnzEwQwFbBMfQGmRZSRoEsXK8lr4I=; b=OMlyIIVKzf0wz+d+LINHZyRALKwOEAybAz8+JD0BccbvNaVABFVeqRvkE4tlvkDjKJ4y bHvdwkBh9CHByxv6P8hDwAbnECX0uIB8TBAEIAYPEE4iW/iW0NgNgPoP1og/x9Zipoo7 z0h4hVKZoU+WaO2Z02RoEAMuMjV8Q1AuI5VASi+j37AshVbletDhiLHsgTKO283WuoRt A3VlTtg+ErbGR7ZPcdDhksvYOaoGcdJZh9IVxQg8cF1qlKK6UQXpNDGuFovyFABZpEfG ebmmbSYGFWxDRVJHJc+8/IerDNfx3K5Rws0/MZ7JATaFR37kft/3K1OCUt6/acvfo169 +A== Received: from ma1-mtap-s02.corp.apple.com (ma1-mtap-s02.corp.apple.com [17.40.76.6]) by nwk-aaemail-lapp03.apple.com with ESMTP id 2ny42efp17-2 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NO); Thu, 29 Nov 2018 14:27:43 -0800 Content-transfer-encoding: 7BIT Received: from nwk-mmpp-sz10.apple.com (nwk-mmpp-sz10.apple.com [17.128.115.122]) by ma1-mtap-s02.corp.apple.com (Oracle Communications Messaging Server 8.0.2.3.20180614 64bit (built Jun 14 2018)) with ESMTPS id <0PIZ00M4G7Q5P260@ma1-mtap-s02.corp.apple.com>; Thu, 29 Nov 2018 14:27:43 -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 <0PIZ00K007LDK400@nwk-mmpp-sz10.apple.com>; Thu, 29 Nov 2018 14:27:42 -0800 (PST) X-Va-A: X-Va-T-CD: 3261cd830d760c0410952f995736816b X-Va-E-CD: 7810d9d388262f49dfb2c5ef16f82d13 X-Va-R-CD: e1456f28e01896a319d644492453f0a7 X-Va-CD: 0 X-Va-ID: b61eec02-c669-4711-aad7-55b53d09d258 X-V-A: X-V-T-CD: 9282bafb218900537fab2921e7776c7e X-V-E-CD: 7810d9d388262f49dfb2c5ef16f82d13 X-V-R-CD: e1456f28e01896a319d644492453f0a7 X-V-CD: 0 X-V-ID: 5dfd16a7-3896-4b86-a882-3019e49c1876 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 <0PIZ00K007LAK300@nwk-mmpp-sz10.apple.com>; Thu, 29 Nov 2018 14:27:42 -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 <0PIZ00FHM7Q6NG70@nwk-mmpp-sz10.apple.com>; Thu, 29 Nov 2018 14:27:42 -0800 (PST) From: Christoph Paasch To: David Miller Cc: netdev@vger.kernel.org, Prashant Bhole , Tyler Hicks Subject: [PATCH net] net: Prevent invalid access to skb->prev in __qdisc_drop_all Date: Thu, 29 Nov 2018 14:27:12 -0800 Message-id: <20181129222712.8396-1-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 There are places in the stack, where we access skb->prev directly and modify it. Namely, __qdisc_drop_all(). 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 also set to NULL when removing it from the list. The bug is in v4.19.x as well, but the patch can't be backported easily. I can post a follow-up for that. Cc: Prashant Bhole Cc: Tyler Hicks Fixes: 68d2f84a1368 ("net: gro: properly remove skb from list") Signed-off-by: Christoph Paasch --- include/linux/skbuff.h | 1 + 1 file changed, 1 insertion(+) diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 0d1b2c3f127b..3bb3bfd390eb 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -1373,6 +1373,7 @@ static inline void skb_zcopy_abort(struct sk_buff *skb) static inline void skb_mark_not_on_list(struct sk_buff *skb) { skb->next = NULL; + skb->prev = NULL; } static inline void skb_list_del_init(struct sk_buff *skb)