Re: [PATCH v2 5/7] regulator: plug of_node leak in regulator_register()'s error path

2020-08-13 Thread Vladimir Zapolskiy 
On 8/12/20 5:09 PM, Michał Mirosław wrote:
> On Wed, Aug 12, 2020 at 09:29:12AM +0300, Vladimir Zapolskiy wrote:
>> On 8/12/20 4:31 AM, Michał Mirosław wrote:
> [...]
>>> config = kmemdup(cfg, sizeof(*cfg), GFP_KERNEL);
>>> if (config == NULL) {
>>> -   kfree(rdev);
>>> ret = -ENOMEM;
>>> -   goto rinse;
>>> +   goto clean;
> [...]
>>>  clean:
>>> if (dangling_of_gpiod)
>>> gpiod_put(config->ena_gpiod);
>>
>> And above 'config' NULL pointer could be dereferenced now, right?
> 
> If config is NULL, dangling_of_gpiod cannot be true.
> 

It's true, thanks. Probably to avoid the known if(false) it might be better
to add a new goto label.

Also it seems to me that it's safe to enter regulator_dev_release() before
doing an assignment to rdev->dev.of_node and incrementing an of_node counter.

Reviewed-by: Vladimir Zapolskiy 

--
Best wishes,
Vladimir

Re: [PATCH v2 5/7] regulator: plug of_node leak in regulator_register()'s error path

2020-08-12 Thread Michał Mirosław 
On Wed, Aug 12, 2020 at 09:29:12AM +0300, Vladimir Zapolskiy wrote:
> On 8/12/20 4:31 AM, Michał Mirosław wrote:
[...]
> > config = kmemdup(cfg, sizeof(*cfg), GFP_KERNEL);
> > if (config == NULL) {
> > -   kfree(rdev);
> > ret = -ENOMEM;
> > -   goto rinse;
> > +   goto clean;
[...]
> >  clean:
> > if (dangling_of_gpiod)
> > gpiod_put(config->ena_gpiod);
> 
> And above 'config' NULL pointer could be dereferenced now, right?

If config is NULL, dangling_of_gpiod cannot be true.

Best Regards,
Michał Mirosław

Re: [PATCH v2 5/7] regulator: plug of_node leak in regulator_register()'s error path

2020-08-12 Thread Vladimir Zapolskiy 
Hi Michał,

On 8/12/20 4:31 AM, Michał Mirosław wrote:
> By calling device_initialize() earlier and noting that kfree(NULL) is
> ok, we can save a bit of code in error handling and plug of_node leak.
> Fixed commit already did part of the work.
> 
> Cc: sta...@vger.kernel.org
> Fixes: 9177514ce349 ("regulator: fix memory leak on error path of 
> regulator_register()")
> Signed-off-by: Michał Mirosław 
> Acked-by: Vladimir Zapolskiy 
> ---
>  drivers/regulator/core.c | 13 -
>  1 file changed, 4 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
> index 71749f48caee..448a267641df 100644
> --- a/drivers/regulator/core.c
> +++ b/drivers/regulator/core.c
> @@ -5137,6 +5137,7 @@ regulator_register(const struct regulator_desc 
> *regulator_desc,
>   ret = -ENOMEM;
>   goto rinse;
>   }
> + device_initialize(>dev);
>  
>   /*
>* Duplicate the config so the driver could override it after
> @@ -5144,9 +5145,8 @@ regulator_register(const struct regulator_desc 
> *regulator_desc,
>*/
>   config = kmemdup(cfg, sizeof(*cfg), GFP_KERNEL);
>   if (config == NULL) {
> - kfree(rdev);
>   ret = -ENOMEM;
> - goto rinse;
> + goto clean;

Here config == NULL

>   }
>  
>   init_data = regulator_of_get_init_data(dev, regulator_desc, config,
> @@ -5158,10 +5158,8 @@ regulator_register(const struct regulator_desc 
> *regulator_desc,
>* from a gpio extender or something else.
>*/
>   if (PTR_ERR(init_data) == -EPROBE_DEFER) {
> - kfree(config);
> - kfree(rdev);
>   ret = -EPROBE_DEFER;
> - goto rinse;
> + goto clean;
>   }
>  
>   /*
> @@ -5214,7 +5212,6 @@ regulator_register(const struct regulator_desc 
> *regulator_desc,
>   }
>  
>   /* register with sysfs */
> - device_initialize(>dev);
>   rdev->dev.class = _class;
>   rdev->dev.parent = dev;
>   dev_set_name(>dev, "regulator.%lu",
> @@ -5292,13 +5289,11 @@ regulator_register(const struct regulator_desc 
> *regulator_desc,
>   mutex_lock(_list_mutex);
>   regulator_ena_gpio_free(rdev);
>   mutex_unlock(_list_mutex);
> - put_device(>dev);
> - rdev = NULL;
>  clean:
>   if (dangling_of_gpiod)
>   gpiod_put(config->ena_gpiod);

And above 'config' NULL pointer could be dereferenced now, right?

> - kfree(rdev);
>   kfree(config);
> + put_device(>dev);
>  rinse:
>   if (dangling_cfg_gpiod)
>   gpiod_put(cfg->ena_gpiod);
> 

--
Best wishes,
Vladimir