Re:Re: [PATCH] HID: fix a crash in hid_debug_events_release

[be286]

Hi Rahul,


When hid_debug_events_release() was being called, in most case,
hid_device_release() finish already, the memory of list->hdev 
freed by hid_device_release(), if list->hdev memory  
reallocate by others, and it's modified, zeroed, then 
list->hdev->debug_list_lock occasioned crash come out.

The runing order:

[  258.201069] CPU: 0 PID: 203 Comm: kworker/0:2 Not tainted 5.10.110 #255
[  258.201073] Hardware name: Rockchip RK3588 EVB4 LP4 V10 Board (DT)
[  258.201086] Workqueue: usb_hub_wq hub_event
[  258.201092] Call trace:
[  258.201100] dump_backtrace+0x0/0x1f8
[  258.201105] show_stack+0x1c/0x2c
[  258.201112] dump_stack_lvl+0xd8/0x12c
[  258.201116] dump_stack+0x1c/0x60
[  258.201122] hid_device_release+0x94/0xb4
[  258.201127] device_release+0x38/0x94
[  258.201133] kobject_cleanup+0xd0/0x174
[  258.201137] kobject_put+0x68/0xa8
[  258.201143] put_device+0x1c/0x2c
[  258.201146] hid_destroy_device+0x60/0x74
[  258.201153] usbhid_disconnect+0x5c/0x90
[  258.201157] usb_unbind_interface+0xc4/0x268
[  258.201162] device_release_driver_internal+0x184/0x25c
[  258.201165] device_release_driver+0x1c/0x2c
[  258.201169] bus_remove_device+0xdc/0x138
[  258.201173] device_del+0x1d0/0x3d8
[  258.201177] usb_disable_device+0x108/0x228
[  258.201181] usb_disconnect+0xf4/0x304
[  258.201184] usb_disconnect+0xdc/0x304
[  258.201188] hub_port_connect+0x88/0xa24
[  258.201191] hub_port_connect_change+0x2d8/0x4cc
[  258.201195] port_event+0x550/0x614
[  258.201198] hub_event+0x12c/0x494
[  258.201203] process_one_work+0x1f4/0x490
[  258.201207] worker_thread+0x278/0x4dc
[  258.201211] kthread+0x130/0x338
[  258.201215] ret_from_fork+0x10/0x30
[  259.925641] CPU: 1 PID: 2354 Comm: hidt_bridge Not tainted 5.10.110 #255
[  259.925652] Hardware name: Rockchip RK3588 EVB4 LP4 V10 Board (DT)
[  259.925656] Call trace:
[  259.925671] dump_backtrace+0x0/0x1f8
[  259.925676] show_stack+0x1c/0x2c
[  259.925685] dump_stack_lvl+0xd8/0x12c
[  259.925689] dump_stack+0x1c/0x60
[  259.925697] hid_debug_events_release+0x24/0x134
[  259.925704] full_proxy_release+0x50/0xbc
[  259.925709] __fput+0xdc/0x238
[  259.925714] ____fput+0x14/0x24
[  259.925720] task_work_run+0x90/0x148
[  259.925725] do_exit+0x1bc/0x8a4
[  259.925729] do_group_exit+0x8c/0xa4
[  259.925734] get_signal+0x468/0x744
[  259.925739] do_signal+0x84/0x280
[  259.925743] do_notify_resume+0xd8/0x228
[  259.925747] work_pending+0xc/0x3f0

The crash:

[  120.728477][ T4396] kernel BUG at lib/list_debug.c:53!
[  120.728505][ T4396] Internal error: Oops - BUG: 0 [#1] PREEMPT SMP
[  120.739806][ T4396] Modules linked in: bcmdhd dhd_static_buf 8822cu pcie_mhi r8168
[  120.747386][ T4396] CPU: 1 PID: 4396 Comm: hidt_bridge Not tainted 5.10.110 #257
[  120.754771][ T4396] Hardware name: Rockchip RK3588 EVB4 LP4 V10 Board (DT)
[  120.761643][ T4396] pstate: 60400089 (nZCv daIf +PAN -UAO -TCO BTYPE=--)
[  120.768338][ T4396] pc : __list_del_entry_valid+0x98/0xac
[  120.773730][ T4396] lr : __list_del_entry_valid+0x98/0xac
[  120.779120][ T4396] sp : ffffffc01e62bb60
[  120.783126][ T4396] x29: ffffffc01e62bb60 x28: ffffff818ce3a200 
[  120.789126][ T4396] x27: 0000000000000009 x26: 0000000000980000 
[  120.795126][ T4396] x25: ffffffc012431000 x24: ffffff802c6d4e00 
[  120.801125][ T4396] x23: ffffff8005c66f00 x22: ffffffc01183b5b8 
[  120.807125][ T4396] x21: ffffff819df2f100 x20: 0000000000000000 
[  120.813124][ T4396] x19: ffffff802c3f0700 x18: ffffffc01d2cd058 
[  120.819124][ T4396] x17: 0000000000000000 x16: 0000000000000000 
[  120.825124][ T4396] x15: 0000000000000004 x14: 0000000000003fff 
[  120.831123][ T4396] x13: ffffffc012085588 x12: 0000000000000003 
[  120.837123][ T4396] x11: 00000000ffffbfff x10: 0000000000000003 
[  120.843123][ T4396] x9 : 455103d46b329300 x8 : 455103d46b329300 
[  120.849124][ T4396] x7 : 74707572726f6320 x6 : ffffffc0124b8cb5 
[  120.855124][ T4396] x5 : ffffffffffffffff x4 : 0000000000000000 
[  120.861123][ T4396] x3 : ffffffc011cf4f90 x2 : ffffff81fee7b948 
[  120.867122][ T4396] x1 : ffffffc011cf4f90 x0 : 0000000000000054 
[  120.873122][ T4396] Call trace:
[  120.876259][ T4396]  __list_del_entry_valid+0x98/0xac
[  120.881304][ T4396]  hid_debug_events_release+0x48/0x12c
[  120.886617][ T4396]  full_proxy_release+0x50/0xbc
[  120.891323][ T4396]  __fput+0xdc/0x238
[  120.895075][ T4396]  ____fput+0x14/0x24
[  120.898911][ T4396]  task_work_run+0x90/0x148
[  120.903268][ T4396]  do_exit+0x1bc/0x8a4
[  120.907193][ T4396]  do_group_exit+0x8c/0xa4
[  120.911458][ T4396]  get_signal+0x468/0x744
[  120.915643][ T4396]  do_signal+0x84/0x280
[  120.919650][ T4396]  do_notify_resume+0xd0/0x218
[  120.924262][ T4396]  work_pending+0xc/0x3f0










At 2023-10-23 23:03:35, "Rahul Rameshbabu" <sergeantsagara@xxxxxxxxxxxxxx> wrote:
>Hi Charles,
>
>On Mon, 23 Oct, 2023 17:35:00 +0800 "Charles Yi" <be286@xxxxxxx> wrote:
>> hid_debug_events_release() access released memory by
>> hid_device_release(). This is fixed by the patch.
>>
>
>A couple of things here. Can you add a Fixes: tag?
>
>https://www.kernel.org/doc/html/latest/process/submitting-patches.html#describe-your-changes
>
>Before any v2 however, it would be nice to understand where this issue
>is coming from. I am wondering if it's really a core issue or rather an
>issue with a higher level device specific driver making use of the hid
>subsystem. I am having a hard time seeing how this issue occurs
>currently. A stack trace in a follow-up email to this one pertaining to
>the crash would be helpful. If you are resolving a syzbot report, a link
>to that report would suffice.
>
>This patch doesn't make a lot of sense to me as-is because
>hid_debug_events_release is about release resources related to hid debug
>events (at least from my current understanding). It should not be
>free-ing the underlying hid device/instance itself.
>
>> Signed-off-by: Charles Yi <be286@xxxxxxx>
>> ---
>>  drivers/hid/hid-core.c  | 12 ++++++++++--
>>  drivers/hid/hid-debug.c |  3 +++
>>  include/linux/hid.h     |  3 +++
>>  3 files changed, 16 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c
>> index 8992e3c1e769..e0181218ad85 100644
>> --- a/drivers/hid/hid-core.c
>> +++ b/drivers/hid/hid-core.c
>> @@ -702,15 +702,22 @@ static void hid_close_report(struct hid_device *device)
>>   * Free a device structure, all reports, and all fields.
>>   */
>>
>> -static void hid_device_release(struct device *dev)
>> +void hiddev_free(struct kref *ref)
>>  {
>> -	struct hid_device *hid = to_hid_device(dev);
>> +	struct hid_device *hid = container_of(ref, struct hid_device, ref);
>>
>>  	hid_close_report(hid);
>>  	kfree(hid->dev_rdesc);
>>  	kfree(hid);
>>  }
>>
>> +static void hid_device_release(struct device *dev)
>> +{
>> +	struct hid_device *hid = to_hid_device(dev);
>> +
>> +	kref_put(&hid->ref, hiddev_free);
>> +}
>> +
>>  /*
>>   * Fetch a report description item from the data stream. We support long
>>   * items, though they are not used yet.
>> @@ -2846,6 +2853,7 @@ struct hid_device *hid_allocate_device(void)
>>  	spin_lock_init(&hdev->debug_list_lock);
>>  	sema_init(&hdev->driver_input_lock, 1);
>>  	mutex_init(&hdev->ll_open_lock);
>> +	kref_init(&hdev->ref);
>>
>>  	hid_bpf_device_init(hdev);
>>
>> diff --git a/drivers/hid/hid-debug.c b/drivers/hid/hid-debug.c
>> index e7ef1ea107c9..7dd83ec74f8a 100644
>> --- a/drivers/hid/hid-debug.c
>> +++ b/drivers/hid/hid-debug.c
>> @@ -1135,6 +1135,7 @@ static int hid_debug_events_open(struct inode *inode, struct file *file)
>>  		goto out;
>>  	}
>>  	list->hdev = (struct hid_device *) inode->i_private;
>> +	kref_get(&list->hdev->ref);
>>  	file->private_data = list;
>>  	mutex_init(&list->read_mutex);
>>
>> @@ -1227,6 +1228,8 @@ static int hid_debug_events_release(struct inode *inode, struct file *file)
>>  	list_del(&list->node);
>>  	spin_unlock_irqrestore(&list->hdev->debug_list_lock, flags);
>>  	kfifo_free(&list->hid_debug_fifo);
>> +
>> +	kref_put(&list->hdev->ref, hiddev_free);
>>  	kfree(list);
>>
>>  	return 0;
>> diff --git a/include/linux/hid.h b/include/linux/hid.h
>> index 964ca1f15e3f..3b08a2957229 100644
>> --- a/include/linux/hid.h
>> +++ b/include/linux/hid.h
>> @@ -679,6 +679,7 @@ struct hid_device {							/* device report descriptor */
>>  	struct list_head debug_list;
>>  	spinlock_t  debug_list_lock;
>>  	wait_queue_head_t debug_wait;
>> +	struct kref			ref;
>>
>>  	unsigned int id;						/* system unique id */
>>
>> @@ -687,6 +688,8 @@ struct hid_device {							/* device report descriptor */
>>  #endif /* CONFIG_BPF */
>>  };
>>
>> +void hiddev_free(struct kref *ref);
>> +
>>  #define to_hid_device(pdev) \
>>  	container_of(pdev, struct hid_device, dev)
>
>--
>Thank you for the patch,
>
>Rahul Rameshbabu