linux/drivers/char/ipmi
Wu Bo ffb76a86f8 ipmi: Fix UAF when uninstall ipmi_si and ipmi_msghandler module
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: b2cfd8ab4a ("ipmi: Rework device id and guid handling to catch changing BMCs")
Signed-off-by: Wu Bo <wubo40@huawei.com>
Message-Id: <1640070034-56671-1-git-send-email-wubo40@huawei.com>
Signed-off-by: Corey Minyard <cminyard@mvista.com>
2021-12-21 08:04:42 -06:00
..
bt-bmc.c ipmi: bt: Add ast2600 compatible string 2021-10-07 14:02:45 -05:00
ipmb_dev_int.c ipmi: remove open coded version of SMBus block write 2021-01-28 07:15:12 -06:00
ipmi_bt_sm.c ipmi: Clean up some printks 2020-09-15 09:57:45 -05:00
ipmi_devintf.c ipmi:devintf: Return a proper error when recv buffer too small 2021-10-05 06:54:16 -05:00
ipmi_dmi.c ipmi_si: Rework some include files 2019-08-02 07:25:03 -05:00
ipmi_dmi.h ipmi_si: Rework some include files 2019-08-02 07:25:03 -05:00
ipmi_ipmb.c ipmi:ipmb: Add OF support 2021-10-14 11:17:18 -05:00
ipmi_kcs_sm.c ipmi: Clean up some printks 2020-09-15 09:57:45 -05:00
ipmi_msghandler.c ipmi: Fix UAF when uninstall ipmi_si and ipmi_msghandler module 2021-12-21 08:04:42 -06:00
ipmi_plat_data.c ipmi: Handle device properties with software node API 2021-03-10 19:00:02 -06:00
ipmi_plat_data.h ipmi: Add the i2c-addr property for SSIF interfaces 2019-04-24 09:02:53 -05:00
ipmi_powernv.c ipmi:powernv: Convert ipmi_smi_t to struct ipmi_smi 2018-09-18 16:15:33 -05:00
ipmi_poweroff.c ipmi: Use more common logging styles 2018-09-18 16:15:33 -05:00
ipmi_si_hardcode.c ipmi_si: Join string literals back 2021-04-02 12:53:42 -05:00
ipmi_si_hotmod.c ipmi_si: Join string literals back 2021-04-02 12:53:42 -05:00
ipmi_si_intf.c char: ipmi: replace snprintf in show functions with sysfs_emit 2021-10-21 06:54:12 -05:00
ipmi_si_mem_io.c ipmi_si: Rework some include files 2019-08-02 07:25:03 -05:00
ipmi_si_parisc.c parisc: Make struct parisc_driver::remove() return void 2021-08-30 10:18:25 +02:00
ipmi_si_pci.c ipmi_si: Join string literals back 2021-04-02 12:53:42 -05:00
ipmi_si_platform.c parisc: Make struct parisc_driver::remove() return void 2021-08-30 10:18:25 +02:00
ipmi_si_port_io.c ipmi_si: Rework some include files 2019-08-02 07:25:03 -05:00
ipmi_si_sm.h ipmi_si: Rework some include files 2019-08-02 07:25:03 -05:00
ipmi_si.h parisc: Make struct parisc_driver::remove() return void 2021-08-30 10:18:25 +02:00
ipmi_smic_sm.c ipmi: Clean up some printks 2020-09-15 09:57:45 -05:00
ipmi_ssif.c ipmi: ssif: initialize ssif_info->client early 2021-12-08 07:13:37 -06:00
ipmi_watchdog.c ipmi: Disable some operations during a panic 2021-10-05 06:54:16 -05:00
Kconfig ipmi: ipmb: fix dependencies to eliminate build error 2021-10-14 11:17:18 -05:00
kcs_bmc_aspeed.c ipmi: kcs_bmc_aspeed: Fix less than zero comparison of a unsigned int 2021-06-21 19:50:36 -05:00
kcs_bmc_cdev_ipmi.c ipmi: kcs_bmc: Decouple the IPMI chardev from the core 2021-06-21 19:50:22 -05:00
kcs_bmc_client.h ipmi: kcs_bmc: Allow clients to control KCS IRQ state 2021-06-21 19:50:28 -05:00
kcs_bmc_device.h ipmi: kcs_bmc: Allow clients to control KCS IRQ state 2021-06-21 19:50:28 -05:00
kcs_bmc_npcm7xx.c ipmi: kcs_bmc: Enable IBF on open 2021-06-21 19:50:28 -05:00
kcs_bmc_serio.c ipmi: kcs_bmc: Fix a memory leak in the error handling path of 'kcs_bmc_serio_add_device()' 2021-10-29 07:23:59 -05:00
kcs_bmc.c ipmi: kcs_bmc: Enable IBF on open 2021-06-21 19:50:28 -05:00
kcs_bmc.h ipmi: kcs_bmc: Allow clients to control KCS IRQ state 2021-06-21 19:50:28 -05:00
Makefile ipmi:ipmb: Add initial support for IPMI over IPMB 2021-10-05 06:54:17 -05:00