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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id DC8A6C433F5 for ; Tue, 21 Dec 2021 06:25:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233443AbhLUGZW (ORCPT ); Tue, 21 Dec 2021 01:25:22 -0500 Received: from szxga01-in.huawei.com ([45.249.212.187]:15955 "EHLO szxga01-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230245AbhLUGZV (ORCPT ); Tue, 21 Dec 2021 01:25:21 -0500 Received: from dggpeml500024.china.huawei.com (unknown [172.30.72.55]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4JJ5w40Y9KzZdhn; Tue, 21 Dec 2021 14:22:12 +0800 (CST) Received: from dggpeml500019.china.huawei.com (7.185.36.137) by dggpeml500024.china.huawei.com (7.185.36.10) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.20; Tue, 21 Dec 2021 14:25:19 +0800 Received: from huawei.com (10.175.124.27) by dggpeml500019.china.huawei.com (7.185.36.137) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.20; Tue, 21 Dec 2021 14:25:19 +0800 From: Wu Bo To: CC: , , , Subject: [PATCH v2] ipmi: Fix UAF when uninstall ipmi_si and ipmi_msghandler module Date: Tue, 21 Dec 2021 15:00:34 +0800 Message-ID: <1640070034-56671-1-git-send-email-wubo40@huawei.com> X-Mailer: git-send-email 1.8.3.1 MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.175.124.27] X-ClientProxiedBy: dggems704-chm.china.huawei.com (10.3.19.181) To dggpeml500019.china.huawei.com (7.185.36.137) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, When testing install and uninstall of ipmi_si.ko and ipmi_msghandler.ko, the system crashed. The log as follows: [ 141.087026] BUG: unable to handle kernel paging request at ffffffffc09b3a5a [ 141.087241] PGD 8fe4c0d067 P4D 8fe4c0d067 PUD 8fe4c0f067 PMD 103ad89067 PTE 0 [ 141.087464] Oops: 0010 [#1] SMP NOPTI [ 141.087580] CPU: 67 PID: 668 Comm: kworker/67:1 Kdump: loaded Not tainted 4.18.0.x86_64 #47 [ 141.088009] Workqueue: events 0xffffffffc09b3a40 [ 141.088009] RIP: 0010:0xffffffffc09b3a5a [ 141.088009] Code: Bad RIP value. [ 141.088009] RSP: 0018:ffffb9094e2c3e88 EFLAGS: 00010246 [ 141.088009] RAX: 0000000000000000 RBX: ffff9abfdb1f04a0 RCX: 0000000000000000 [ 141.088009] RDX: 0000000000000000 RSI: 0000000000000246 RDI: 0000000000000246 [ 141.088009] RBP: 0000000000000000 R08: ffff9abfffee3cb8 R09: 00000000000002e1 [ 141.088009] R10: ffffb9094cb73d90 R11: 00000000000f4240 R12: ffff9abfffee8700 [ 141.088009] R13: 0000000000000000 R14: ffff9abfdb1f04a0 R15: ffff9abfdb1f04a8 [ 141.088009] FS: 0000000000000000(0000) GS:ffff9abfffec0000(0000) knlGS:0000000000000000 [ 141.088009] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 141.088009] CR2: ffffffffc09b3a30 CR3: 0000008fe4c0a001 CR4: 00000000007606e0 [ 141.088009] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 141.088009] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 141.088009] PKRU: 55555554 [ 141.088009] Call Trace: [ 141.088009] ? process_one_work+0x195/0x390 [ 141.088009] ? worker_thread+0x30/0x390 [ 141.088009] ? process_one_work+0x390/0x390 [ 141.088009] ? kthread+0x10d/0x130 [ 141.088009] ? kthread_flush_work_fn+0x10/0x10 [ 141.088009] ? ret_from_fork+0x35/0x40] BUG: unable to handle kernel paging request at ffffffffc0b28a5a [ 200.223240] PGD 97fe00d067 P4D 97fe00d067 PUD 97fe00f067 PMD a580cbf067 PTE 0 [ 200.223464] Oops: 0010 [#1] SMP NOPTI [ 200.223579] CPU: 63 PID: 664 Comm: kworker/63:1 Kdump: loaded Not tainted 4.18.0.x86_64 #46 [ 200.224008] Workqueue: events 0xffffffffc0b28a40 [ 200.224008] RIP: 0010:0xffffffffc0b28a5a [ 200.224008] Code: Bad RIP value. [ 200.224008] RSP: 0018:ffffbf3c8e2a3e88 EFLAGS: 00010246 [ 200.224008] RAX: 0000000000000000 RBX: ffffa0799ad6bca0 RCX: 0000000000000000 [ 200.224008] RDX: 0000000000000000 RSI: 0000000000000246 RDI: 0000000000000246 [ 200.224008] RBP: 0000000000000000 R08: ffff9fe43fde3cb8 R09: 00000000000000d5 [ 200.224008] R10: ffffbf3c8cb53d90 R11: 00000000000f4240 R12: ffff9fe43fde8700 [ 200.224008] R13: 0000000000000000 R14: ffffa0799ad6bca0 R15: ffffa0799ad6bca8 [ 200.224008] FS: 0000000000000000(0000) GS:ffff9fe43fdc0000(0000) knlGS:0000000000000000 [ 200.224008] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 200.224008] CR2: ffffffffc0b28a30 CR3: 00000097fe00a002 CR4: 00000000007606e0 [ 200.224008] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 200.224008] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 200.224008] PKRU: 55555554 [ 200.224008] Call Trace: [ 200.224008] ? process_one_work+0x195/0x390 [ 200.224008] ? worker_thread+0x30/0x390 [ 200.224008] ? process_one_work+0x390/0x390 [ 200.224008] ? kthread+0x10d/0x130 [ 200.224008] ? kthread_flush_work_fn+0x10/0x10 [ 200.224008] ? ret_from_fork+0x35/0x40 [ 200.224008] kernel fault(0x1) notification starting on CPU 63 [ 200.224008] kernel fault(0x1) notification finished on CPU 63 [ 200.224008] CR2: ffffffffc0b28a5a [ 200.224008] ---[ end trace c82a412d93f57412 ]--- The reason is as follows: T1: rmmod ipmi_si. ->ipmi_unregister_smi() -> ipmi_bmc_unregister() -> __ipmi_bmc_unregister() -> kref_put(&bmc->usecount, cleanup_bmc_device); -> schedule_work(&bmc->remove_work); T2: rmmod ipmi_msghandler. ipmi_msghander module uninstalled, and the module space will be freed. T3: bmc->remove_work doing cleanup the bmc resource. -> cleanup_bmc_work() -> platform_device_unregister(&bmc->pdev); -> platform_device_del(pdev); -> device_del(&pdev->dev); -> kobject_uevent(&dev->kobj, KOBJ_REMOVE); -> kobject_uevent_env() -> dev_uevent() -> if (dev->type && dev->type->name) 'dev->type'(bmc_device_type) pointer space has freed when uninstall ipmi_msghander module, 'dev->type->name' cause the system crash. drivers/char/ipmi/ipmi_msghandler.c: 2820 static const struct device_type bmc_device_type = { 2821 .groups = bmc_dev_attr_groups, 2822 }; Steps to reproduce: Add a time delay in cleanup_bmc_work() function, and uninstall ipmi_si and ipmi_msghandler module. 2910 static void cleanup_bmc_work(struct work_struct *work) 2911 { 2912 struct bmc_device *bmc = container_of(work, struct bmc_device, 2913 remove_work); 2914 int id = bmc->pdev.id; /* Unregister overwrites id */ 2915 2916 msleep(3000); <--- 2917 platform_device_unregister(&bmc->pdev); 2918 ida_simple_remove(&ipmi_bmc_ida, id); 2919 } Use 'remove_work_wq' instead of 'system_wq' to solve this issues. Fixes: b2cfd8ab4add ("ipmi: Rework device id and guid handling to catch changing BMCs") Signed-off-by: Wu Bo --- drivers/char/ipmi/ipmi_msghandler.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/char/ipmi/ipmi_msghandler.c b/drivers/char/ipmi/ipmi_msghandler.c index c837d54..d96184d 100644 --- a/drivers/char/ipmi/ipmi_msghandler.c +++ b/drivers/char/ipmi/ipmi_msghandler.c @@ -3031,7 +3031,7 @@ static void cleanup_bmc_work(struct work_struct *work) * with removing the device attributes while reading a device * attribute. */ - schedule_work(&bmc->remove_work); + queue_work(remove_work_wq, &bmc->remove_work); } /* -- 1.8.3.1