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

[Andy Shevchenko]

On Wed, Sep 11, 2024 at 11:19:15PM +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.
> 
> 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

Sounds legit to me. But I have no time to review, FWIW,
Acked-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>

I believe Sebastian will conduct a proper review before applying.

-- 
With Best Regards,
Andy Shevchenko