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

[Frank Li]

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


>  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
>