ipmi: Fix UAF when uninstall ipmi_si and ipmi_msghandler module
[ Upstream commit
ffb76a86f8096a8206be03b14adda6092e18e275 ]
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 <wubo40@huawei.com>
Message-Id: <
1640070034-56671-1-git-send-email-wubo40@huawei.com>
Signed-off-by: Corey Minyard <cminyard@mvista.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>