Re: [PATCH 6.1.y] i3c: master: cdns: Fix use after free vulnerability in cdns_i3c_master Driver Due to Race Condition

[Greg KH]

On Fri, Jan 03, 2025 at 03:04:20PM +0800, jianqi.ren.cn@xxxxxxxxxxxxx wrote:
> From: Kaixin Wang <kxwang23@xxxxxxxxxxxxxx>
> 
> [ Upstream commit 609366e7a06d035990df78f1562291c3bf0d4a12 ]
> 
> In the cdns_i3c_master_probe function, &master->hj_work is bound with
> cdns_i3c_master_hj. And cdns_i3c_master_interrupt can call
> cnds_i3c_master_demux_ibis function to start the work.
> 
> If we remove the module which will call cdns_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
> 
>                                      | cdns_i3c_master_hj
> cdns_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 cdns_i3c_master_remove.
> 
> Signed-off-by: Kaixin Wang <kxwang23@xxxxxxxxxxxxxx>
> Link: https://lore.kernel.org/r/20240911153544.848398-1-kxwang23@xxxxxxxxxxxxxx
> Signed-off-by: Alexandre Belloni <alexandre.belloni@xxxxxxxxxxx>
> Signed-off-by: Jianqi Ren <jianqi.ren.cn@xxxxxxxxxxxxx>

Wait, why are you all submitting stable patches again?  I thought I
asked you to change how you all did this AND discuss it with me after
you came up with a plan on how to move forward.

What happened to all of that?  I'm dropping this, and the other
submission you sent as nothing seems to have changed :(

greg k-h