2023-03-09 18:11:03

by Zheng Wang

[permalink] [raw]
Subject: [PATCH] power: supply: da9150: Fix use after free bug in da9150_charger_remove due to race condition

In da9150_charger_probe, &charger->otg_work is bound with
da9150_charger_otg_work. da9150_charger_otg_ncb may be
called to start the work.

If we remove the module which will call da9150_charger_remove
to make cleanup, there may be a unfinished work. The possible
sequence is as follows:

Fix it by canceling the work before cleanup in the mtk_jpeg_remove

CPU0 CPUc1

|da9150_charger_otg_work
da9150_charger_remove |
power_supply_unregister |
device_unregister |
power_supply_dev_release|
kfree(psy) |
|
| power_supply_changed(charger->usb);
| //use
Fixes: c1a281e34dae ("power: Add support for DA9150 Charger")
Signed-off-by: Zheng Wang <[email protected]>
---
drivers/power/supply/da9150-charger.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/drivers/power/supply/da9150-charger.c b/drivers/power/supply/da9150-charger.c
index 14da5c595dd9..41b68f2f6ed8 100644
--- a/drivers/power/supply/da9150-charger.c
+++ b/drivers/power/supply/da9150-charger.c
@@ -642,6 +642,7 @@ static int da9150_charger_remove(struct platform_device *pdev)
struct da9150_charger *charger = platform_get_drvdata(pdev);
int irq;

+ cancel_work_sync(&charger->otg_work);
/* Make sure IRQs are released before unregistering power supplies */
irq = platform_get_irq_byname(pdev, "CHG_VBUS");
free_irq(irq, charger);
--
2.25.1



2023-03-09 23:39:23

by Sebastian Reichel

[permalink] [raw]
Subject: Re: [PATCH] power: supply: da9150: Fix use after free bug in da9150_charger_remove due to race condition

Hi,

On Fri, Mar 10, 2023 at 02:10:36AM +0800, Zheng Wang wrote:
> In da9150_charger_probe, &charger->otg_work is bound with
> da9150_charger_otg_work. da9150_charger_otg_ncb may be
> called to start the work.
>
> If we remove the module which will call da9150_charger_remove
> to make cleanup, there may be a unfinished work. The possible
> sequence is as follows:
>
> Fix it by canceling the work before cleanup in the mtk_jpeg_remove

mtk_jpeg_remove?

>
> CPU0 CPUc1
>
> |da9150_charger_otg_work
> da9150_charger_remove |
> power_supply_unregister |
> device_unregister |
> power_supply_dev_release|
> kfree(psy) |
> |
> | power_supply_changed(charger->usb);
> | //use
> Fixes: c1a281e34dae ("power: Add support for DA9150 Charger")
> Signed-off-by: Zheng Wang <[email protected]>
> ---

Looks correct to me, but the cancel_work_sync should happen after
usb_unregister_notifier(), otherwise there is still a race
condition.

-- Sebastian

> drivers/power/supply/da9150-charger.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/drivers/power/supply/da9150-charger.c b/drivers/power/supply/da9150-charger.c
> index 14da5c595dd9..41b68f2f6ed8 100644
> --- a/drivers/power/supply/da9150-charger.c
> +++ b/drivers/power/supply/da9150-charger.c
> @@ -642,6 +642,7 @@ static int da9150_charger_remove(struct platform_device *pdev)
> struct da9150_charger *charger = platform_get_drvdata(pdev);
> int irq;
>
> + cancel_work_sync(&charger->otg_work);
> /* Make sure IRQs are released before unregistering power supplies */
> irq = platform_get_irq_byname(pdev, "CHG_VBUS");
> free_irq(irq, charger);
> --
> 2.25.1
>


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2023-03-10 16:28:37

by Zheng Hacker

[permalink] [raw]
Subject: Re: [PATCH] power: supply: da9150: Fix use after free bug in da9150_charger_remove due to race condition

Sebastian Reichel <[email protected]> 于2023年3月10日周五 07:39写道:
>
> Hi,
>
> On Fri, Mar 10, 2023 at 02:10:36AM +0800, Zheng Wang wrote:
> > In da9150_charger_probe, &charger->otg_work is bound with
> > da9150_charger_otg_work. da9150_charger_otg_ncb may be
> > called to start the work.
> >
> > If we remove the module which will call da9150_charger_remove
> > to make cleanup, there may be a unfinished work. The possible
> > sequence is as follows:
> >
> > Fix it by canceling the work before cleanup in the mtk_jpeg_remove
>
> mtk_jpeg_remove?

Sorry that's mistake. I will correct it in the next version of patch.

>
> >
> > CPU0 CPUc1
> >
> > |da9150_charger_otg_work
> > da9150_charger_remove |
> > power_supply_unregister |
> > device_unregister |
> > power_supply_dev_release|
> > kfree(psy) |
> > |
> > | power_supply_changed(charger->usb);
> > | //use
> > Fixes: c1a281e34dae ("power: Add support for DA9150 Charger")
> > Signed-off-by: Zheng Wang <[email protected]>
> > ---
>
> Looks correct to me, but the cancel_work_sync should happen after
> usb_unregister_notifier(), otherwise there is still a race
> condition.

Yes, I agree that. Thanks for pointing that out. Will do in the next path.

Best regards,
Zheng

>
> > drivers/power/supply/da9150-charger.c | 1 +
> > 1 file changed, 1 insertion(+)
> >
> > diff --git a/drivers/power/supply/da9150-charger.c b/drivers/power/supply/da9150-charger.c
> > index 14da5c595dd9..41b68f2f6ed8 100644
> > --- a/drivers/power/supply/da9150-charger.c
> > +++ b/drivers/power/supply/da9150-charger.c
> > @@ -642,6 +642,7 @@ static int da9150_charger_remove(struct platform_device *pdev)
> > struct da9150_charger *charger = platform_get_drvdata(pdev);
> > int irq;
> >
> > + cancel_work_sync(&charger->otg_work);
> > /* Make sure IRQs are released before unregistering power supplies */
> > irq = platform_get_irq_byname(pdev, "CHG_VBUS");
> > free_irq(irq, charger);
> > --
> > 2.25.1
> >

2023-03-10 16:29:13

by Zheng Hacker

[permalink] [raw]
Subject: Re: [PATCH] power: supply: bq24190: Fix use after free bug in bq24190_remove due to race condition

Sebastian Reichel <[email protected]> 于2023年3月10日周五 07:40写道:
>
> Hi,
>
> On Fri, Mar 10, 2023 at 01:47:28AM +0800, Zheng Wang wrote:
> > In bq24190_probe, &bdi->input_current_limit_work is bound
> > with bq24190_input_current_limit_work. When external power
> > changed, it will call bq24190_charger_external_power_changed
> > to start the work.
> >
> > If we remove the module which will call bq24190_remove to make
> > cleanup, there may be a unfinished work. The possible
> > sequence is as follows:
> >
> > CPU0 CPUc1
> >
> > |bq24190_input_current_limit_work
> > bq24190_remove |
> > power_supply_unregister |
> > device_unregister |
> > power_supply_dev_release|
> > kfree(psy) |
> > |
> > | power_supply_get_property_from_supplier
> > | //use
> >
> > Fix it by finishing the work before cleanup in the bq24190_remove
> >
> > Fixes: 97774672573a ("power_supply: Initialize changed_work before calling device_add")
> > Signed-off-by: Zheng Wang <[email protected]>
> > ---
>
> Thanks, queued to fixes branch.
>
Very glad to hear that. Thanks for your effort.

Best regards,
Zheng

>
> > drivers/power/supply/bq24190_charger.c | 1 +
> > 1 file changed, 1 insertion(+)
> >
> > diff --git a/drivers/power/supply/bq24190_charger.c b/drivers/power/supply/bq24190_charger.c
> > index be34b9848450..de67b985f0a9 100644
> > --- a/drivers/power/supply/bq24190_charger.c
> > +++ b/drivers/power/supply/bq24190_charger.c
> > @@ -1906,6 +1906,7 @@ static void bq24190_remove(struct i2c_client *client)
> > struct bq24190_dev_info *bdi = i2c_get_clientdata(client);
> > int error;
> >
> > + cancel_delayed_work_sync(&bdi->input_current_limit_work);
> > error = pm_runtime_resume_and_get(bdi->dev);
> > if (error < 0)
> > dev_warn(bdi->dev, "pm_runtime_get failed: %i\n", error);
> > --
> > 2.25.1
> >