linux/drivers/char
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
..
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hw_random vhost,virtio,vhost: fixes,features 2021-11-03 15:00:39 -07:00
ipmi ipmi: Fix UAF when uninstall ipmi_si and ipmi_msghandler module 2021-12-21 08:04:42 -06:00
mwave char: mware: fix returnvar.cocci warnings 2021-08-27 16:20:37 +02:00
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xilinx_hwicap treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
xillybus char: xillybus: fix msg_ep UAF in xillyusb_probe() 2021-10-19 09:40:18 +02:00
adi.c
apm-emulation.c treewide: Add SPDX license identifier for more missed files 2019-05-21 10:50:45 +02:00
applicom.c Merge 5.12-rc6 into char-misc-next 2021-04-05 08:43:50 +02:00
applicom.h
bsr.c mm: don't include asm/pgtable.h if linux/mm.h is already included 2020-06-09 09:39:13 -07:00
ds1620.c treewide: Add SPDX license identifier for more missed files 2019-05-21 10:50:45 +02:00
dsp56k.c
dtlk.c treewide: Add SPDX license identifier for more missed files 2019-05-21 10:50:45 +02:00
hangcheck-timer.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 405 2019-06-05 17:37:13 +02:00
hpet.c char: hpet: Remove unused variable 'm' 2021-05-21 10:09:30 +02:00
Kconfig char: move RANDOM_TRUST_CPU & RANDOM_TRUST_BOOTLOADER into the Character devices menu 2021-08-16 19:02:19 +02:00
lp.c char: lp: remove redundant space around (inside) parenthesized expressions 2021-03-24 08:26:32 +01:00
Makefile remove the raw driver 2021-06-04 15:35:03 +02:00
mem.c /dev/mem: nowait zero/null ops 2021-09-14 10:46:19 +02:00
misc.c char: misc: increase DYNAMIC_MINORS value 2020-11-03 09:52:04 +01:00
mspec.c char: mspec: Use kvzalloc() in mspec_mmap() 2020-08-28 12:10:04 +02:00
nsc_gpio.c treewide: Add SPDX license identifier for more missed files 2019-05-21 10:50:45 +02:00
nvram.c treewide: Use fallthrough pseudo-keyword 2020-08-23 17:36:59 -05:00
nwbutton.c treewide: Add SPDX license identifier for more missed files 2019-05-21 10:50:45 +02:00
nwbutton.h misc: cleanup minor number definitions in c file into miscdevice.h 2020-03-18 12:27:03 +01:00
nwflash.c misc: move FLASH_MINOR into miscdevice.h and fix conflicts 2020-03-18 12:27:04 +01:00
pc8736x_gpio.c treewide: Add SPDX license identifier for more missed files 2019-05-21 10:50:45 +02:00
powernv-op-panel.c powerpc/powernv: Fix fall-through warning for Clang 2021-07-13 19:21:41 -05:00
ppdev.c ppdev: Distribute switch variables for initialization 2020-02-23 20:28:12 +01:00
ps3flash.c powerpc/ps3: make system bus's remove and shutdown callbacks return void 2020-12-04 01:01:22 +11:00
random.c random: remove dead code left over from blocking pool 2021-04-02 18:28:12 +11:00
scx200_gpio.c treewide: Add SPDX license identifier for more missed files 2019-05-21 10:50:45 +02:00
sonypi.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 61 2019-05-24 17:36:45 +02:00
tb0219.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156 2019-05-30 11:26:35 -07:00
tlclk.c drivers: char: tlclk.c: Avoid data race between init and interrupt handler 2020-04-23 16:55:24 +02:00
toshiba.c module: remove never implemented MODULE_SUPPORTED_DEVICE 2021-03-17 13:16:18 -07:00
ttyprintk.c tty: drop put_tty_driver 2021-07-27 12:17:21 +02:00
uv_mmtimer.c
virtio_console.c virtio_console: validate max_nr_ports before trying to use it 2021-11-01 05:26:48 -04:00