Re: [PATCH] i3c: master: svc: Fix use after free vulnerability in svc_i3c_master Driver Due to Race Condition

[Kaixin Wang]

在 2024-09-11 23:24:57，"Frank Li" <Frank.li@xxxxxxx> 写道：
>On Wed, Sep 11, 2024 at 11:01:35PM +0800, Kaixin Wang wrote:
>> In the svc_i3c_master_probe function, &master->hj_work is bound with
>> svc_i3c_master_hj_work, &master->ibi_work is bound with
>> svc_i3c_master_ibi_work. And svc_i3c_master_ibi_work  can start the
>> hj_work, svc_i3c_master_irq_handler can start the ibi_work.
>>
>> If we remove the module which will call svc_i3c_master_remove to
>> make cleanup, it will free master->base through i3c_master_unregister
>> while the work mentioned above will be used. The sequence of operations
>> that may lead to a UAF bug is as follows:
>>
>> CPU0                                         CPU1
>>
>>                                     | svc_i3c_master_hj_work
>> svc_i3c_master_remove               |
>> i3c_master_unregister(&master->base)|
>> device_unregister(&master->dev)     |
>> device_release                      |
>> //free master->base                 |
>>                                     | i3c_master_do_daa(&master->base)
>>                                     | //use master->base
>>
>> Fix it by ensuring that the work is canceled before proceeding with the
>> cleanup in svc_i3c_master_remove.
>>
>> Signed-off-by: Kaixin Wang <kxwang23@xxxxxxxxxxxxxx>
>> ---
>
>Please add fixes tag and cc stable.
>
>Frank
>

I will add them in the next version of the patch.

Best regards,
Kaixin Wang

>
>>  drivers/i3c/master/svc-i3c-master.c | 1 +
>>  1 file changed, 1 insertion(+)
>>
>> diff --git a/drivers/i3c/master/svc-i3c-master.c b/drivers/i3c/master/svc-i3c-master.c
>> index 0a68fd1b81d4..e084ba648b4a 100644
>> --- a/drivers/i3c/master/svc-i3c-master.c
>> +++ b/drivers/i3c/master/svc-i3c-master.c
>> @@ -1775,6 +1775,7 @@ static void svc_i3c_master_remove(struct platform_device *pdev)
>>  {
>>  	struct svc_i3c_master *master = platform_get_drvdata(pdev);
>>
>> +	cancel_work_sync(&master->hj_work);
>>  	i3c_master_unregister(&master->base);
>>
>>  	pm_runtime_dont_use_autosuspend(&pdev->dev);
>> --
>> 2.25.1
>>
>