* [PATCH] USB: gadget: udc: Fix use after free bug in udc_plat_remove due to race condition
@ 2023-03-10 7:00 Zheng Wang
2023-03-23 16:20 ` Greg KH
0 siblings, 1 reply; 3+ messages in thread
From: Zheng Wang @ 2023-03-10 7:00 UTC (permalink / raw)
To: gregkh
Cc: linux-usb, linux-kernel, hackerzheng666, 1395428693sheep,
alex000young, Zheng Wang
In udc_plat_probe, &udc->drd_work is bound with
udc_drd_work. udc_drd_work may be called by
usbd_connect_notify to start the work.
Besides, there is a invoking chain:
udc_plat_probe
->udc_probe
->usb_add_gadget_udc_release
->usb_add_gadget
It will add a new gadget to the udc class driver
list. In usb_add_gadget, it uses usb_udc_release
as its release function, which will kfree(udc)
to when destroying the gadget.
If we remove the module which will call udc_plat_remove
to make cleanup, there may be a unfinished work.
The possible sequence is as follows:
Fix it by finishing the work before cleanup in the udc_plat_remove
Fixes: 1b9f35adb0ff ("usb: gadget: udc: Add Synopsys UDC Platform driver")
Signed-off-by: Zheng Wang <zyytlz.wz@163.com>
---
drivers/usb/gadget/udc/snps_udc_plat.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/drivers/usb/gadget/udc/snps_udc_plat.c b/drivers/usb/gadget/udc/snps_udc_plat.c
index 8bbb89c80348..6228e178cc0a 100644
--- a/drivers/usb/gadget/udc/snps_udc_plat.c
+++ b/drivers/usb/gadget/udc/snps_udc_plat.c
@@ -230,6 +230,7 @@ static int udc_plat_remove(struct platform_device *pdev)
struct udc *dev;
dev = platform_get_drvdata(pdev);
+ cancel_delayed_work_sync(&dev->drd_work);
usb_del_gadget_udc(&dev->gadget);
/* gadget driver must not be registered */
--
2.25.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] USB: gadget: udc: Fix use after free bug in udc_plat_remove due to race condition
2023-03-10 7:00 [PATCH] USB: gadget: udc: Fix use after free bug in udc_plat_remove due to race condition Zheng Wang
@ 2023-03-23 16:20 ` Greg KH
2023-03-24 15:34 ` Zheng Hacker
0 siblings, 1 reply; 3+ messages in thread
From: Greg KH @ 2023-03-23 16:20 UTC (permalink / raw)
To: Zheng Wang
Cc: linux-usb, linux-kernel, hackerzheng666, 1395428693sheep, alex000young
On Fri, Mar 10, 2023 at 03:00:39PM +0800, Zheng Wang wrote:
> In udc_plat_probe, &udc->drd_work is bound with
> udc_drd_work. udc_drd_work may be called by
> usbd_connect_notify to start the work.
>
> Besides, there is a invoking chain:
> udc_plat_probe
> ->udc_probe
> ->usb_add_gadget_udc_release
> ->usb_add_gadget
>
> It will add a new gadget to the udc class driver
> list. In usb_add_gadget, it uses usb_udc_release
> as its release function, which will kfree(udc)
> to when destroying the gadget.
>
> If we remove the module which will call udc_plat_remove
> to make cleanup, there may be a unfinished work.
> The possible sequence is as follows:
>
> Fix it by finishing the work before cleanup in the udc_plat_remove
>
> Fixes: 1b9f35adb0ff ("usb: gadget: udc: Add Synopsys UDC Platform driver")
> Signed-off-by: Zheng Wang <zyytlz.wz@163.com>
> ---
> drivers/usb/gadget/udc/snps_udc_plat.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/drivers/usb/gadget/udc/snps_udc_plat.c b/drivers/usb/gadget/udc/snps_udc_plat.c
> index 8bbb89c80348..6228e178cc0a 100644
> --- a/drivers/usb/gadget/udc/snps_udc_plat.c
> +++ b/drivers/usb/gadget/udc/snps_udc_plat.c
> @@ -230,6 +230,7 @@ static int udc_plat_remove(struct platform_device *pdev)
> struct udc *dev;
>
> dev = platform_get_drvdata(pdev);
> + cancel_delayed_work_sync(&dev->drd_work);
>
> usb_del_gadget_udc(&dev->gadget);
> /* gadget driver must not be registered */
> --
> 2.25.1
>
Please test this to verify that it actually works.
thanks,
greg k-h
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] USB: gadget: udc: Fix use after free bug in udc_plat_remove due to race condition
2023-03-23 16:20 ` Greg KH
@ 2023-03-24 15:34 ` Zheng Hacker
0 siblings, 0 replies; 3+ messages in thread
From: Zheng Hacker @ 2023-03-24 15:34 UTC (permalink / raw)
To: Greg KH
Cc: Zheng Wang, linux-usb, linux-kernel, 1395428693sheep, alex000young
Greg KH <gregkh@linuxfoundation.org> 于2023年3月24日周五 00:20写道:
>
> On Fri, Mar 10, 2023 at 03:00:39PM +0800, Zheng Wang wrote:
> > In udc_plat_probe, &udc->drd_work is bound with
> > udc_drd_work. udc_drd_work may be called by
> > usbd_connect_notify to start the work.
> >
> > Besides, there is a invoking chain:
> > udc_plat_probe
> > ->udc_probe
> > ->usb_add_gadget_udc_release
> > ->usb_add_gadget
> >
> > It will add a new gadget to the udc class driver
> > list. In usb_add_gadget, it uses usb_udc_release
> > as its release function, which will kfree(udc)
> > to when destroying the gadget.
> >
> > If we remove the module which will call udc_plat_remove
> > to make cleanup, there may be a unfinished work.
> > The possible sequence is as follows:
> >
> > Fix it by finishing the work before cleanup in the udc_plat_remove
> >
> > Fixes: 1b9f35adb0ff ("usb: gadget: udc: Add Synopsys UDC Platform driver")
> > Signed-off-by: Zheng Wang <zyytlz.wz@163.com>
> > ---
> > drivers/usb/gadget/udc/snps_udc_plat.c | 1 +
> > 1 file changed, 1 insertion(+)
> >
> > diff --git a/drivers/usb/gadget/udc/snps_udc_plat.c b/drivers/usb/gadget/udc/snps_udc_plat.c
> > index 8bbb89c80348..6228e178cc0a 100644
> > --- a/drivers/usb/gadget/udc/snps_udc_plat.c
> > +++ b/drivers/usb/gadget/udc/snps_udc_plat.c
> > @@ -230,6 +230,7 @@ static int udc_plat_remove(struct platform_device *pdev)
> > struct udc *dev;
> >
> > dev = platform_get_drvdata(pdev);
> > + cancel_delayed_work_sync(&dev->drd_work);
> >
> > usb_del_gadget_udc(&dev->gadget);
> > /* gadget driver must not be registered */
> > --
> > 2.25.1
> >
>
> Please test this to verify that it actually works.
>
Hi,
Sorry for my late reply. I will try to simulate a device in qemu to test.
Best regards,
Zheng
> thanks,
>
> greg k-h
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2023-03-24 15:35 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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2023-03-10 7:00 [PATCH] USB: gadget: udc: Fix use after free bug in udc_plat_remove due to race condition Zheng Wang
2023-03-23 16:20 ` Greg KH
2023-03-24 15:34 ` Zheng Hacker
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