Re: [PATCH v2] HSI: ssi_protocol: Fix use after free vulnerability in ssi_protocol Driver Due to Race Condition

[Kaixin Wang]

At 2024-09-16 18:39:46, "Andy Shevchenko" <andriy.shevchenko@xxxxxxxxxxxxxxx> wrote:
>On Sun, Sep 15, 2024 at 01:21:43AM +0800, Kaixin Wang wrote:
>> In the ssi_protocol_probe function, &ssi->work is bound with
>> ssip_xmit_work, In ssip_pn_setup, the ssip_pn_xmit function
>> within the ssip_pn_ops structure is capable of starting the
>> work.
>
>We refer to the functions as func(). E.g., ssip_pn_setup(),
>ssip_pn_xmit().
>

I will correct it.

>> If we remove the module which will call ssi_protocol_remove
>> to make a cleanup, it will free ssi through kfree(ssi),
>> while the work mentioned above will be used. The sequence
>> of operations that may lead to a UAF bug is as follows:
>> 
>> CPU0                                    CPU1
>> 
>>                         | ssip_xmit_work
>> ssi_protocol_remove     |
>> kfree(ssi);             |
>>                         | struct hsi_client *cl = ssi->cl;
>>                         | // use ssi
>> 
>> Fix it by ensuring that the work is canceled before proceeding
>> with the cleanup in ssi_protocol_remove.
>
>Same here.
>

I will correct it.

>...
>
>> Acked-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
>
>> - add the Acked-by label from Andy
>
>Not that Ack was given to _this_ version of the change (it has been changed
>a lot), but I'm fine with keeping it.
>

Sorry, I missed this point.

>-- 
>With Best Regards,
>Andy Shevchenko
>
>
>

Best regards,
Kaixin Wang