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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 63926C433EF for ; Mon, 25 Oct 2021 08:37:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 43F0160555 for ; Mon, 25 Oct 2021 08:37:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232148AbhJYIkG (ORCPT ); Mon, 25 Oct 2021 04:40:06 -0400 Received: from szxga02-in.huawei.com ([45.249.212.188]:14863 "EHLO szxga02-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231727AbhJYIkG (ORCPT ); Mon, 25 Oct 2021 04:40:06 -0400 Received: from dggeml757-chm.china.huawei.com (unknown [172.30.72.56]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4Hd7ch3sr6z90F6; Mon, 25 Oct 2021 16:37:40 +0800 (CST) Received: from [10.174.179.200] (10.174.179.200) by dggeml757-chm.china.huawei.com (10.1.199.137) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2308.15; Mon, 25 Oct 2021 16:37:41 +0800 Subject: Re: [PATCH rdma-rc] IB/core: fix a UAF for netdev in netdevice_event process To: Leon Romanovsky CC: , , , , , , References: <20211025034258.2426872-1-william.xuanziyang@huawei.com> From: "Ziyang Xuan (William)" Message-ID: <00f99243-919a-d697-646a-0e200c0aef81@huawei.com> Date: Mon, 25 Oct 2021 16:37:41 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.11.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="gbk" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.174.179.200] X-ClientProxiedBy: dggems701-chm.china.huawei.com (10.3.19.178) To dggeml757-chm.china.huawei.com (10.1.199.137) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org > On Mon, Oct 25, 2021 at 11:42:58AM +0800, Ziyang Xuan wrote: >> When a vlan netdev enter netdevice_event process although it is not a >> roce netdev, it will be passed to netdevice_event_work_handler() to >> process. In order to hold the netdev of netdevice_event after >> netdevice_event() return, call dev_hold() to hold the netdev in >> netdevice_queue_work(). But that did not consider the real_dev of a vlan >> netdev, the real_dev can be freed within netdevice_event_work_handler() >> be scheduled. It would trigger the UAF problem for the real_dev like >> following: >> >> ================================================================== >> BUG: KASAN: use-after-free in vlan_dev_real_dev+0xf9/0x120 >> Read of size 4 at addr ffff88801648a0c4 by task kworker/u8:0/8 >> Workqueue: gid-cache-wq netdevice_event_work_handler >> Call Trace: >> dump_stack_lvl+0xcd/0x134 >> print_address_description.constprop.0.cold+0x93/0x334 >> kasan_report.cold+0x83/0xdf >> vlan_dev_real_dev+0xf9/0x120 >> is_eth_port_of_netdev_filter.part.0+0xb1/0x2c0 >> is_eth_port_of_netdev_filter+0x28/0x40 >> ib_enum_roce_netdev+0x1a3/0x300 >> ib_enum_all_roce_netdevs+0xc7/0x140 >> netdevice_event_work_handler+0x9d/0x210 >> ... >> >> Allocated by task 9289: >> kasan_save_stack+0x1b/0x40 >> __kasan_kmalloc+0x9b/0xd0 >> __kmalloc_node+0x20a/0x330 >> kvmalloc_node+0x61/0xf0 >> alloc_netdev_mqs+0x9d/0x1140 >> rtnl_create_link+0x955/0xb70 >> __rtnl_newlink+0xe10/0x15b0 >> rtnl_newlink+0x64/0xa0 >> ... >> >> Freed by task 9288: >> kasan_save_stack+0x1b/0x40 >> kasan_set_track+0x1c/0x30 >> kasan_set_free_info+0x20/0x30 >> __kasan_slab_free+0xfc/0x130 >> slab_free_freelist_hook+0xdd/0x240 >> kfree+0xe4/0x690 >> kvfree+0x42/0x50 >> device_release+0x9f/0x240 >> kobject_put+0x1c8/0x530 >> put_device+0x1b/0x30 >> free_netdev+0x370/0x540 >> ppp_destroy_interface+0x313/0x3d0 >> ppp_release+0x1bf/0x240 >> ... >> >> Hold the real_dev for a vlan netdev in netdevice_event_work_handler() >> to fix the UAF problem. >> >> Fixes: 238fdf48f2b5 ("IB/core: Add RoCE table bonding support") >> Reported-by: syzbot+e4df4e1389e28972e955@syzkaller.appspotmail.com >> Signed-off-by: Ziyang Xuan >> --- >> drivers/infiniband/core/roce_gid_mgmt.c | 16 +++++++++++++++- >> 1 file changed, 15 insertions(+), 1 deletion(-) >> >> diff --git a/drivers/infiniband/core/roce_gid_mgmt.c b/drivers/infiniband/core/roce_gid_mgmt.c >> index 68197e576433..063dbe72b7c2 100644 >> --- a/drivers/infiniband/core/roce_gid_mgmt.c >> +++ b/drivers/infiniband/core/roce_gid_mgmt.c >> @@ -621,6 +621,7 @@ static void netdevice_event_work_handler(struct work_struct *_work) >> { >> struct netdev_event_work *work = >> container_of(_work, struct netdev_event_work, work); >> + struct net_device *real_dev; >> unsigned int i; >> >> for (i = 0; i < ARRAY_SIZE(work->cmds) && work->cmds[i].cb; i++) { >> @@ -628,6 +629,12 @@ static void netdevice_event_work_handler(struct work_struct *_work) >> work->cmds[i].filter_ndev, >> work->cmds[i].cb, >> work->cmds[i].ndev); >> + real_dev = rdma_vlan_dev_real_dev(work->cmds[i].ndev); >> + if (real_dev) >> + dev_put(real_dev); >> + real_dev = rdma_vlan_dev_real_dev(work->cmds[i].filter_ndev); >> + if (real_dev) >> + dev_put(real_dev); >> dev_put(work->cmds[i].ndev); >> dev_put(work->cmds[i].filter_ndev); >> } >> @@ -638,9 +645,10 @@ static void netdevice_event_work_handler(struct work_struct *_work) >> static int netdevice_queue_work(struct netdev_event_work_cmd *cmds, >> struct net_device *ndev) >> { >> - unsigned int i; >> struct netdev_event_work *ndev_work = >> kmalloc(sizeof(*ndev_work), GFP_KERNEL); >> + struct net_device *real_dev; >> + unsigned int i; >> >> if (!ndev_work) >> return NOTIFY_DONE; >> @@ -653,6 +661,12 @@ static int netdevice_queue_work(struct netdev_event_work_cmd *cmds, >> ndev_work->cmds[i].filter_ndev = ndev; >> dev_hold(ndev_work->cmds[i].ndev); >> dev_hold(ndev_work->cmds[i].filter_ndev); >> + real_dev = rdma_vlan_dev_real_dev(ndev_work->cmds[i].ndev); >> + if (real_dev) >> + dev_hold(real_dev); >> + real_dev = rdma_vlan_dev_real_dev(ndev_work->cmds[i].filter_ndev); >> + if (real_dev) >> + dev_hold(real_dev); >> } >> INIT_WORK(&ndev_work->work, netdevice_event_work_handler); > > Probably, this is the right change, but I don't know well enough that > part of code. What prevents from "real_dev" to disappear right after > your call to rdma_vlan_dev_real_dev()? > It is known that free the net_device until its dev_refcnt is one. The detail realization see netdev_run_todo().The real_dev's dev_refcnt of a vlan net_device will reach one after unregister_netdevice(&real_dev) and unregister_vlan_dev(&vlan_ndev, ...) but the dev_refcnt of the vlan net_device is bigger than one because netdevice_queue_work() will hold the vlan net_device. So my solution is hold the real_dev too in netdevice_queue_work(). > Thanks > >> >> -- >> 2.25.1 >> > . >