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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 AC01DC433FF for ; Fri, 9 Aug 2019 13:46:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 775FE21783 for ; Fri, 9 Aug 2019 13:46:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1565358388; bh=6UxfYpK0qSYNYk4aE4AYe/piWuilHAcBgxnRuaLEmOM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=jaTqYS8S747GrkimpCifwM7nxuAsLw2kQsPvi2ncdT0lanykcYm0UUc95smayVZCR MvmxxE5iA33yGq5Js9wNwPHH6eooTE2rwpk1B+pZ70O8sICjHnjMAAVtSPME/HQeFh yAL8VeSIu+ktensKNixwECq89EbqwmTx2KOO2irI= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2436500AbfHINq1 (ORCPT ); Fri, 9 Aug 2019 09:46:27 -0400 Received: from mail.kernel.org ([198.145.29.99]:35894 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2406984AbfHINqU (ORCPT ); Fri, 9 Aug 2019 09:46:20 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 6DE54214C6; Fri, 9 Aug 2019 13:46:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1565358378; bh=6UxfYpK0qSYNYk4aE4AYe/piWuilHAcBgxnRuaLEmOM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=AQbDjLh7CQhL/rI686TdYRkfFpkvyMoEVceg0sJSwY057lpiqfGctssoa6tKdh1lg /R9juK0E2b2Z7XfgR1PXm5ZFhMM60k5UE46lnpb//I+zqARViljwmwZKSqC/IwJI2S rl89d1NBS6LS7VsYYTQrIjqkeCSTnRSA47zvzNC8= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jiri Pirko , "David S. Miller" Subject: [PATCH 4.4 08/21] net: fix ifindex collision during namespace removal Date: Fri, 9 Aug 2019 15:45:12 +0200 Message-Id: <20190809134241.921747969@linuxfoundation.org> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190809134241.565496442@linuxfoundation.org> References: <20190809134241.565496442@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Jiri Pirko [ Upstream commit 55b40dbf0e76b4bfb9d8b3a16a0208640a9a45df ] Commit aca51397d014 ("netns: Fix arbitrary net_device-s corruptions on net_ns stop.") introduced a possibility to hit a BUG in case device is returning back to init_net and two following conditions are met: 1) dev->ifindex value is used in a name of another "dev%d" device in init_net. 2) dev->name is used by another device in init_net. Under real life circumstances this is hard to get. Therefore this has been present happily for over 10 years. To reproduce: $ ip a 1: lo: mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127.0.0.1/8 scope host lo valid_lft forever preferred_lft forever inet6 ::1/128 scope host valid_lft forever preferred_lft forever 2: dummy0: mtu 1500 qdisc noop state DOWN group default qlen 1000 link/ether 86:89:3f:86:61:29 brd ff:ff:ff:ff:ff:ff 3: enp0s2: mtu 1500 qdisc noop state DOWN group default qlen 1000 link/ether 52:54:00:12:34:56 brd ff:ff:ff:ff:ff:ff $ ip netns add ns1 $ ip -n ns1 link add dummy1ns1 type dummy $ ip -n ns1 link add dummy2ns1 type dummy $ ip link set enp0s2 netns ns1 $ ip -n ns1 link set enp0s2 name dummy0 [ 100.858894] virtio_net virtio0 dummy0: renamed from enp0s2 $ ip link add dev4 type dummy $ ip -n ns1 a 1: lo: mtu 65536 qdisc noop state DOWN group default qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 2: dummy1ns1: mtu 1500 qdisc noop state DOWN group default qlen 1000 link/ether 16:63:4c:38:3e:ff brd ff:ff:ff:ff:ff:ff 3: dummy2ns1: mtu 1500 qdisc noop state DOWN group default qlen 1000 link/ether aa:9e:86:dd:6b:5d brd ff:ff:ff:ff:ff:ff 4: dummy0: mtu 1500 qdisc noop state DOWN group default qlen 1000 link/ether 52:54:00:12:34:56 brd ff:ff:ff:ff:ff:ff $ ip a 1: lo: mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127.0.0.1/8 scope host lo valid_lft forever preferred_lft forever inet6 ::1/128 scope host valid_lft forever preferred_lft forever 2: dummy0: mtu 1500 qdisc noop state DOWN group default qlen 1000 link/ether 86:89:3f:86:61:29 brd ff:ff:ff:ff:ff:ff 4: dev4: mtu 1500 qdisc noop state DOWN group default qlen 1000 link/ether 5a:e1:4a:b6:ec:f8 brd ff:ff:ff:ff:ff:ff $ ip netns del ns1 [ 158.717795] default_device_exit: failed to move dummy0 to init_net: -17 [ 158.719316] ------------[ cut here ]------------ [ 158.720591] kernel BUG at net/core/dev.c:9824! [ 158.722260] invalid opcode: 0000 [#1] SMP KASAN PTI [ 158.723728] CPU: 0 PID: 56 Comm: kworker/u2:1 Not tainted 5.3.0-rc1+ #18 [ 158.725422] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-2.fc30 04/01/2014 [ 158.727508] Workqueue: netns cleanup_net [ 158.728915] RIP: 0010:default_device_exit.cold+0x1d/0x1f [ 158.730683] Code: 84 e8 18 c9 3e fe 0f 0b e9 70 90 ff ff e8 36 e4 52 fe 89 d9 4c 89 e2 48 c7 c6 80 d6 25 84 48 c7 c7 20 c0 25 84 e8 f4 c8 3e [ 158.736854] RSP: 0018:ffff8880347e7b90 EFLAGS: 00010282 [ 158.738752] RAX: 000000000000003b RBX: 00000000ffffffef RCX: 0000000000000000 [ 158.741369] RDX: 0000000000000000 RSI: ffffffff8128013d RDI: ffffed10068fcf64 [ 158.743418] RBP: ffff888033550170 R08: 000000000000003b R09: fffffbfff0b94b9c [ 158.745626] R10: fffffbfff0b94b9b R11: ffffffff85ca5cdf R12: ffff888032f28000 [ 158.748405] R13: dffffc0000000000 R14: ffff8880335501b8 R15: 1ffff110068fcf72 [ 158.750638] FS: 0000000000000000(0000) GS:ffff888036000000(0000) knlGS:0000000000000000 [ 158.752944] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 158.755245] CR2: 00007fe8b45d21d0 CR3: 00000000340b4005 CR4: 0000000000360ef0 [ 158.757654] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 158.760012] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 158.762758] Call Trace: [ 158.763882] ? dev_change_net_namespace+0xbb0/0xbb0 [ 158.766148] ? devlink_nl_cmd_set_doit+0x520/0x520 [ 158.768034] ? dev_change_net_namespace+0xbb0/0xbb0 [ 158.769870] ops_exit_list.isra.0+0xa8/0x150 [ 158.771544] cleanup_net+0x446/0x8f0 [ 158.772945] ? unregister_pernet_operations+0x4a0/0x4a0 [ 158.775294] process_one_work+0xa1a/0x1740 [ 158.776896] ? pwq_dec_nr_in_flight+0x310/0x310 [ 158.779143] ? do_raw_spin_lock+0x11b/0x280 [ 158.780848] worker_thread+0x9e/0x1060 [ 158.782500] ? process_one_work+0x1740/0x1740 [ 158.784454] kthread+0x31b/0x420 [ 158.786082] ? __kthread_create_on_node+0x3f0/0x3f0 [ 158.788286] ret_from_fork+0x3a/0x50 [ 158.789871] ---[ end trace defd6c657c71f936 ]--- [ 158.792273] RIP: 0010:default_device_exit.cold+0x1d/0x1f [ 158.795478] Code: 84 e8 18 c9 3e fe 0f 0b e9 70 90 ff ff e8 36 e4 52 fe 89 d9 4c 89 e2 48 c7 c6 80 d6 25 84 48 c7 c7 20 c0 25 84 e8 f4 c8 3e [ 158.804854] RSP: 0018:ffff8880347e7b90 EFLAGS: 00010282 [ 158.807865] RAX: 000000000000003b RBX: 00000000ffffffef RCX: 0000000000000000 [ 158.811794] RDX: 0000000000000000 RSI: ffffffff8128013d RDI: ffffed10068fcf64 [ 158.816652] RBP: ffff888033550170 R08: 000000000000003b R09: fffffbfff0b94b9c [ 158.820930] R10: fffffbfff0b94b9b R11: ffffffff85ca5cdf R12: ffff888032f28000 [ 158.825113] R13: dffffc0000000000 R14: ffff8880335501b8 R15: 1ffff110068fcf72 [ 158.829899] FS: 0000000000000000(0000) GS:ffff888036000000(0000) knlGS:0000000000000000 [ 158.834923] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 158.838164] CR2: 00007fe8b45d21d0 CR3: 00000000340b4005 CR4: 0000000000360ef0 [ 158.841917] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 158.845149] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Fix this by checking if a device with the same name exists in init_net and fallback to original code - dev%d to allocate name - in case it does. This was found using syzkaller. Fixes: aca51397d014 ("netns: Fix arbitrary net_device-s corruptions on net_ns stop.") Signed-off-by: Jiri Pirko Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/core/dev.c | 2 ++ 1 file changed, 2 insertions(+) --- a/net/core/dev.c +++ b/net/core/dev.c @@ -7768,6 +7768,8 @@ static void __net_exit default_device_ex /* Push remaining network devices to init_net */ snprintf(fb_name, IFNAMSIZ, "dev%d", dev->ifindex); + if (__dev_get_by_name(&init_net, fb_name)) + snprintf(fb_name, IFNAMSIZ, "dev%%d"); err = dev_change_net_namespace(dev, &init_net, fb_name); if (err) { pr_emerg("%s: failed to move %s to init_net: %d\n",