[PATCH v3] usb: gadget: udc: renesas_usb3: Fix use after free bug in renesas_usb3_remove due to race condition

[PATCH v3] usb: gadget: udc: renesas_usb3: Fix use after free bug in renesas_usb3_remove due to race condition

[Zheng Wang]

In renesas_usb3_probe, &usb3->role_work is bound with
renesas_usb3_role_work. renesas_usb3_start will be called
to start the work.

If we remove the driver which will call usbhs_remove, there may be
an unfinished work. The possible sequence is as follows:

Fix it by canceling the work before cleanup in the renesas_usb3_remove

CPU0                  CPU1

                    |renesas_usb3_role_work
renesas_usb3_remove |
usb_role_switch_unregister  |
device_unregister   |
kfree(sw)  	     |
free usb3->role_sw  |
                    |   usb_role_switch_set_role
                    |   //use usb3->role_sw

Fixes: 39facfa01c9f ("usb: gadget: udc: renesas_usb3: Add register of usb role switch")
Reviewed-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Signed-off-by: Zheng Wang <zyytlz.wz@163.com>
---
v3:
- modify the commit message to make it clearer suggested by Yoshihiro Shimoda
v2:
- fix typo, use clearer commit message and only cancel the UAF-related work suggested by Yoshihiro Shimoda
---
 drivers/usb/gadget/udc/renesas_usb3.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/usb/gadget/udc/renesas_usb3.c b/drivers/usb/gadget/udc/renesas_usb3.c
index bee6bceafc4f..a301af66bd91 100644
--- a/drivers/usb/gadget/udc/renesas_usb3.c
+++ b/drivers/usb/gadget/udc/renesas_usb3.c
@@ -2661,6 +2661,7 @@ static int renesas_usb3_remove(struct platform_device *pdev)
 	debugfs_remove_recursive(usb3->dentry);
 	device_remove_file(&pdev->dev, &dev_attr_role);
 
+	cancel_work_sync(&usb3->role_work);
 	usb_role_switch_unregister(usb3->role_sw);
 
 	usb_del_gadget_udc(&usb3->gadget);
-- 
2.25.1

RE: [PATCH v3] usb: gadget: udc: renesas_usb3: Fix use after free bug in renesas_usb3_remove due to race condition

[Yoshihiro Shimoda]

Hi Zheng,

> From: Zheng Wang, Sent: Tuesday, March 14, 2023 1:51 AM
> Subject: [PATCH v3] usb: gadget: udc: renesas_usb3: Fix use after free bug in renesas_usb3_remove due to race condition
> 
> In renesas_usb3_probe, &usb3->role_work is bound with
> renesas_usb3_role_work. renesas_usb3_start will be called
> to start the work.
> 
> If we remove the driver which will call usbhs_remove, there may be
> an unfinished work. The possible sequence is as follows:
> 
> Fix it by canceling the work before cleanup in the renesas_usb3_remove
> 
> CPU0                  CPU1
> 
>                     |renesas_usb3_role_work
> renesas_usb3_remove |
> usb_role_switch_unregister  |
> device_unregister   |
> kfree(sw)  	     |
> free usb3->role_sw  |
>                     |   usb_role_switch_set_role
>                     |   //use usb3->role_sw
> 
> Fixes: 39facfa01c9f ("usb: gadget: udc: renesas_usb3: Add register of usb role switch")
> Reviewed-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
> Signed-off-by: Zheng Wang <zyytlz.wz@163.com>

JFYI, but IIUC,
- In general, my Reviewed-by is described here, not top of your Signed-off-by.
- Also, you don't need to submit such this patch. If you would like to submit
  such a patch for some reason (ping or so on), incrementing patch version is
  better because original v3 [1] doesn't have my Reviewed-by tag.

[1]
https://lore.kernel.org/all/20230313094852.3344288-1-zyytlz.wz@163.com/

Best regards,
Yoshihiro Shimoda

> ---
> v3:
> - modify the commit message to make it clearer suggested by Yoshihiro Shimoda
> v2:
> - fix typo, use clearer commit message and only cancel the UAF-related work suggested by Yoshihiro Shimoda
> ---
>  drivers/usb/gadget/udc/renesas_usb3.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/usb/gadget/udc/renesas_usb3.c b/drivers/usb/gadget/udc/renesas_usb3.c
> index bee6bceafc4f..a301af66bd91 100644
> --- a/drivers/usb/gadget/udc/renesas_usb3.c
> +++ b/drivers/usb/gadget/udc/renesas_usb3.c
> @@ -2661,6 +2661,7 @@ static int renesas_usb3_remove(struct platform_device *pdev)
>  	debugfs_remove_recursive(usb3->dentry);
>  	device_remove_file(&pdev->dev, &dev_attr_role);
> 
> +	cancel_work_sync(&usb3->role_work);
>  	usb_role_switch_unregister(usb3->role_sw);
> 
>  	usb_del_gadget_udc(&usb3->gadget);
> --
> 2.25.1

Re: [PATCH v3] usb: gadget: udc: renesas_usb3: Fix use after free bug in renesas_usb3_remove due to race condition

[Zheng Hacker]

Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com> 于2023年3月14日周二 08:16写道：
>
> Hi Zheng,
>
> > From: Zheng Wang, Sent: Tuesday, March 14, 2023 1:51 AM
> > Subject: [PATCH v3] usb: gadget: udc: renesas_usb3: Fix use after free bug in renesas_usb3_remove due to race condition
> >
> > In renesas_usb3_probe, &usb3->role_work is bound with
> > renesas_usb3_role_work. renesas_usb3_start will be called
> > to start the work.
> >
> > If we remove the driver which will call usbhs_remove, there may be
> > an unfinished work. The possible sequence is as follows:
> >
> > Fix it by canceling the work before cleanup in the renesas_usb3_remove
> >
> > CPU0                  CPU1
> >
> >                     |renesas_usb3_role_work
> > renesas_usb3_remove |
> > usb_role_switch_unregister  |
> > device_unregister   |
> > kfree(sw)          |
> > free usb3->role_sw  |
> >                     |   usb_role_switch_set_role
> >                     |   //use usb3->role_sw
> >
> > Fixes: 39facfa01c9f ("usb: gadget: udc: renesas_usb3: Add register of usb role switch")
> > Reviewed-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
> > Signed-off-by: Zheng Wang <zyytlz.wz@163.com>
>
> JFYI, but IIUC,
> - In general, my Reviewed-by is described here, not top of your Signed-off-by.
> - Also, you don't need to submit such this patch. If you would like to submit
>   such a patch for some reason (ping or so on), incrementing patch version is
>   better because original v3 [1] doesn't have my Reviewed-by tag.
>
> [1]
> https://lore.kernel.org/all/20230313094852.3344288-1-zyytlz.wz@163.com/
>

Dear Yoshihir,

Thanks for your advice. I am not familiar with the submission rules, thanks for
your kind reminder. I'll keep that in mind in the future. Have a good day :)

Best regards,
Zheng

> Best regards,
> Yoshihiro Shimoda
>
> > ---
> > v3:
> > - modify the commit message to make it clearer suggested by Yoshihiro Shimoda
> > v2:
> > - fix typo, use clearer commit message and only cancel the UAF-related work suggested by Yoshihiro Shimoda
> > ---
> >  drivers/usb/gadget/udc/renesas_usb3.c | 1 +
> >  1 file changed, 1 insertion(+)
> >
> > diff --git a/drivers/usb/gadget/udc/renesas_usb3.c b/drivers/usb/gadget/udc/renesas_usb3.c
> > index bee6bceafc4f..a301af66bd91 100644
> > --- a/drivers/usb/gadget/udc/renesas_usb3.c
> > +++ b/drivers/usb/gadget/udc/renesas_usb3.c
> > @@ -2661,6 +2661,7 @@ static int renesas_usb3_remove(struct platform_device *pdev)
> >       debugfs_remove_recursive(usb3->dentry);
> >       device_remove_file(&pdev->dev, &dev_attr_role);
> >
> > +     cancel_work_sync(&usb3->role_work);
> >       usb_role_switch_unregister(usb3->role_sw);
> >
> >       usb_del_gadget_udc(&usb3->gadget);
> > --
> > 2.25.1
>

Re: [PATCH v3] usb: gadget: udc: renesas_usb3: Fix use after free bug in renesas_usb3_remove due to race condition

[Greg KH]

On Tue, Mar 14, 2023 at 12:51:28AM +0800, Zheng Wang wrote:
> In renesas_usb3_probe, &usb3->role_work is bound with
> renesas_usb3_role_work. renesas_usb3_start will be called
> to start the work.
> 
> If we remove the driver which will call usbhs_remove, there may be
> an unfinished work. The possible sequence is as follows:
> 
> Fix it by canceling the work before cleanup in the renesas_usb3_remove
> 
> CPU0                  CPU1
> 
>                     |renesas_usb3_role_work
> renesas_usb3_remove |
> usb_role_switch_unregister  |
> device_unregister   |
> kfree(sw)  	     |
> free usb3->role_sw  |
>                     |   usb_role_switch_set_role
>                     |   //use usb3->role_sw
> 
> Fixes: 39facfa01c9f ("usb: gadget: udc: renesas_usb3: Add register of usb role switch")
> Reviewed-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
> Signed-off-by: Zheng Wang <zyytlz.wz@163.com>
> ---
> v3:
> - modify the commit message to make it clearer suggested by Yoshihiro Shimoda

I see 2 v3 patches in the mailing list, which is obviously not correct.

Please resubmit a v4 properly.

thanks,

greg k-h

Re: [PATCH v3] usb: gadget: udc: renesas_usb3: Fix use after free bug in renesas_usb3_remove due to race condition

[Zheng Hacker]

Greg KH <gregkh@linuxfoundation.org> 于2023年3月16日周四 18:55写道：
>
> On Tue, Mar 14, 2023 at 12:51:28AM +0800, Zheng Wang wrote:
> > In renesas_usb3_probe, &usb3->role_work is bound with
> > renesas_usb3_role_work. renesas_usb3_start will be called
> > to start the work.
> >
> > If we remove the driver which will call usbhs_remove, there may be
> > an unfinished work. The possible sequence is as follows:
> >
> > Fix it by canceling the work before cleanup in the renesas_usb3_remove
> >
> > CPU0                  CPU1
> >
> >                     |renesas_usb3_role_work
> > renesas_usb3_remove |
> > usb_role_switch_unregister  |
> > device_unregister   |
> > kfree(sw)          |
> > free usb3->role_sw  |
> >                     |   usb_role_switch_set_role
> >                     |   //use usb3->role_sw
> >
> > Fixes: 39facfa01c9f ("usb: gadget: udc: renesas_usb3: Add register of usb role switch")
> > Reviewed-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
> > Signed-off-by: Zheng Wang <zyytlz.wz@163.com>
> > ---
> > v3:
> > - modify the commit message to make it clearer suggested by Yoshihiro Shimoda
>
> I see 2 v3 patches in the mailing list, which is obviously not correct.
>
> Please resubmit a v4 properly.
>

Hi Greg,

Thanks for your kind reminder. I'll resubmit a v4 patch later.

Best regards,
Zheng

> thanks,
>
> greg k-h

[PATCH v3] usb: gadget: udc: renesas_usb3: Fix use after free bug in renesas_usb3_remove due to race condition

[Zheng Wang]

In renesas_usb3_probe, &usb3->role_work is bound with
renesas_usb3_role_work. renesas_usb3_start will be called
to start the work.

If we remove the driver which will call usbhs_remove, there may be
an unfinished work. The possible sequence is as follows:

Fix it by canceling the work before cleanup in the renesas_usb3_remove

CPU0                  CPU1

                    |renesas_usb3_role_work
renesas_usb3_remove |
usb_role_switch_unregister  |
device_unregister   |
kfree(sw)  	     |
free usb3->role_sw  |
                    |   usb_role_switch_set_role
                    |   //use usb3->role_sw

Fixes: 39facfa01c9f ("usb: gadget: udc: renesas_usb3: Add register of usb role switch")
Signed-off-by: Zheng Wang <zyytlz.wz@163.com>
---
v3:
- modify the commit message to make it clearer suggested by Yoshihiro Shimoda
v2:
- fix typo, use clearer commit message and only cancel the UAF-related work suggested by Yoshihiro Shimoda
---
 drivers/usb/gadget/udc/renesas_usb3.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/usb/gadget/udc/renesas_usb3.c b/drivers/usb/gadget/udc/renesas_usb3.c
index bee6bceafc4f..a301af66bd91 100644
--- a/drivers/usb/gadget/udc/renesas_usb3.c
+++ b/drivers/usb/gadget/udc/renesas_usb3.c
@@ -2661,6 +2661,7 @@ static int renesas_usb3_remove(struct platform_device *pdev)
 	debugfs_remove_recursive(usb3->dentry);
 	device_remove_file(&pdev->dev, &dev_attr_role);
 
+	cancel_work_sync(&usb3->role_work);
 	usb_role_switch_unregister(usb3->role_sw);
 
 	usb_del_gadget_udc(&usb3->gadget);
-- 
2.25.1

RE: [PATCH v3] usb: gadget: udc: renesas_usb3: Fix use after free bug in renesas_usb3_remove due to race condition

[Yoshihiro Shimoda]

Hi Zheng,

> From: Zheng Wang, Sent: Monday, March 13, 2023 6:49 PM
> 
> In renesas_usb3_probe, &usb3->role_work is bound with
> renesas_usb3_role_work. renesas_usb3_start will be called
> to start the work.
> 
> If we remove the driver which will call usbhs_remove, there may be
> an unfinished work. The possible sequence is as follows:
> 
> Fix it by canceling the work before cleanup in the renesas_usb3_remove
> 
> CPU0                  CPU1
> 
>                     |renesas_usb3_role_work
> renesas_usb3_remove |
> usb_role_switch_unregister  |
> device_unregister   |
> kfree(sw)  	     |
> free usb3->role_sw  |
>                     |   usb_role_switch_set_role
>                     |   //use usb3->role_sw
> 
> Fixes: 39facfa01c9f ("usb: gadget: udc: renesas_usb3: Add register of usb role switch")
> Signed-off-by: Zheng Wang <zyytlz.wz@163.com>

Thank you for the patch!

Reviewed-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>

Best regards,
Yoshihiro Shimoda

> ---
> v3:
> - modify the commit message to make it clearer suggested by Yoshihiro Shimoda
> v2:
> - fix typo, use clearer commit message and only cancel the UAF-related work suggested by Yoshihiro Shimoda
> ---
>  drivers/usb/gadget/udc/renesas_usb3.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/usb/gadget/udc/renesas_usb3.c b/drivers/usb/gadget/udc/renesas_usb3.c
> index bee6bceafc4f..a301af66bd91 100644
> --- a/drivers/usb/gadget/udc/renesas_usb3.c
> +++ b/drivers/usb/gadget/udc/renesas_usb3.c
> @@ -2661,6 +2661,7 @@ static int renesas_usb3_remove(struct platform_device *pdev)
>  	debugfs_remove_recursive(usb3->dentry);
>  	device_remove_file(&pdev->dev, &dev_attr_role);
> 
> +	cancel_work_sync(&usb3->role_work);
>  	usb_role_switch_unregister(usb3->role_sw);
> 
>  	usb_del_gadget_udc(&usb3->gadget);
> --
> 2.25.1

Re: [PATCH v3] usb: gadget: udc: renesas_usb3: Fix use after free bug in renesas_usb3_remove due to race condition

[Zheng Hacker]

Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com> 于2023年3月13日周一 20:56写道：
>
> Hi Zheng,
>
> > From: Zheng Wang, Sent: Monday, March 13, 2023 6:49 PM
> >
> > In renesas_usb3_probe, &usb3->role_work is bound with
> > renesas_usb3_role_work. renesas_usb3_start will be called
> > to start the work.
> >
> > If we remove the driver which will call usbhs_remove, there may be
> > an unfinished work. The possible sequence is as follows:
> >
> > Fix it by canceling the work before cleanup in the renesas_usb3_remove
> >
> > CPU0                  CPU1
> >
> >                     |renesas_usb3_role_work
> > renesas_usb3_remove |
> > usb_role_switch_unregister  |
> > device_unregister   |
> > kfree(sw)          |
> > free usb3->role_sw  |
> >                     |   usb_role_switch_set_role
> >                     |   //use usb3->role_sw
> >
> > Fixes: 39facfa01c9f ("usb: gadget: udc: renesas_usb3: Add register of usb role switch")
> > Signed-off-by: Zheng Wang <zyytlz.wz@163.com>
>
> Thank you for the patch!
>
> Reviewed-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
>
Thanks for the detailed review :)

Best regards,
Zheng
>
> > ---
> > v3:
> > - modify the commit message to make it clearer suggested by Yoshihiro Shimoda
> > v2:
> > - fix typo, use clearer commit message and only cancel the UAF-related work suggested by Yoshihiro Shimoda
> > ---
> >  drivers/usb/gadget/udc/renesas_usb3.c | 1 +
> >  1 file changed, 1 insertion(+)
> >
> > diff --git a/drivers/usb/gadget/udc/renesas_usb3.c b/drivers/usb/gadget/udc/renesas_usb3.c
> > index bee6bceafc4f..a301af66bd91 100644
> > --- a/drivers/usb/gadget/udc/renesas_usb3.c
> > +++ b/drivers/usb/gadget/udc/renesas_usb3.c
> > @@ -2661,6 +2661,7 @@ static int renesas_usb3_remove(struct platform_device *pdev)
> >       debugfs_remove_recursive(usb3->dentry);
> >       device_remove_file(&pdev->dev, &dev_attr_role);
> >
> > +     cancel_work_sync(&usb3->role_work);
> >       usb_role_switch_unregister(usb3->role_sw);
> >
> >       usb_del_gadget_udc(&usb3->gadget);
> > --
> > 2.25.1
>