* RE: [PATCH] devfreq: add error check for sscanf in userspace governor
2017-08-07 13:06 ` Santosh Mardi
@ 2017-08-08 0:14 ` MyungJoo Ham
2017-08-08 0:51 ` Chanwoo Choi
2017-08-08 6:56 ` Pavan Kondeti
2 siblings, 0 replies; 6+ messages in thread
From: MyungJoo Ham @ 2017-08-08 0:14 UTC (permalink / raw)
To: Kyungmin Park, rafael.j.wysocki@intel.com, Chanwoo Choi
Cc: linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org,
gsantosh@qti.qualcomm.com, gsantosh@codeaurora.org,
skannan@quicinc.com, rgottimu@qti.qualcomm.com
> store_freq function of devfreq userspace governor
> executes further, even if error is returned from sscanf,
> this will result in setting up wrong frequency value.
>
> Add proper error check to bail out if any error is returned.
>
> Signed-off-by: Santosh Mardi <gsantosh@codeaurora.org>
Acked-by: MyungJoo Ham <myungjoo.ham@samsung.com>
> ---
> drivers/devfreq/governor_userspace.c | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] devfreq: add error check for sscanf in userspace governor
2017-08-07 13:06 ` Santosh Mardi
2017-08-08 0:14 ` MyungJoo Ham
@ 2017-08-08 0:51 ` Chanwoo Choi
2017-08-08 6:56 ` Pavan Kondeti
2 siblings, 0 replies; 6+ messages in thread
From: Chanwoo Choi @ 2017-08-08 0:51 UTC (permalink / raw)
To: Santosh Mardi, myungjoo.ham, kyungmin.park, rafael.j.wysocki
Cc: linux-pm, linux-kernel, gsantosh, skannan, rgottimu
Hi,
On 2017년 08월 07일 22:06, Santosh Mardi wrote:
> store_freq function of devfreq userspace governor
> executes further, even if error is returned from sscanf,
> this will result in setting up wrong frequency value.
>
> Add proper error check to bail out if any error is returned.
>
> Signed-off-by: Santosh Mardi <gsantosh@codeaurora.org>
> ---
> drivers/devfreq/governor_userspace.c | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/devfreq/governor_userspace.c b/drivers/devfreq/governor_userspace.c
> index 77028c2..1d0c9cc 100644
> --- a/drivers/devfreq/governor_userspace.c
> +++ b/drivers/devfreq/governor_userspace.c
> @@ -53,12 +53,15 @@ static ssize_t store_freq(struct device *dev, struct device_attribute *attr,
> mutex_lock(&devfreq->lock);
> data = devfreq->data;
>
> - sscanf(buf, "%lu", &wanted);
> + err = sscanf(buf, "%lu", &wanted);
> + if (err != 1)
> + goto out;
> data->user_frequency = wanted;
> data->valid = true;
> err = update_devfreq(devfreq);
> if (err == 0)
> err = count;
> +out:
> mutex_unlock(&devfreq->lock);
> return err;
> }
>
Looks good to me.
Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com>
--
Best Regards,
Chanwoo Choi
Samsung Electronics
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] devfreq: add error check for sscanf in userspace governor
2017-08-07 13:06 ` Santosh Mardi
2017-08-08 0:14 ` MyungJoo Ham
2017-08-08 0:51 ` Chanwoo Choi
@ 2017-08-08 6:56 ` Pavan Kondeti
2017-08-08 19:26 ` Saravana Kannan
2 siblings, 1 reply; 6+ messages in thread
From: Pavan Kondeti @ 2017-08-08 6:56 UTC (permalink / raw)
To: Santosh Mardi
Cc: myungjoo.ham, kyungmin.park, rafael.j.wysocki, cw00.choi,
linux-pm, LKML, gsantosh, skannan, rgottimu
Hi Santosh,
On Mon, Aug 7, 2017 at 6:36 PM, Santosh Mardi <gsantosh@codeaurora.org> wrote:
> store_freq function of devfreq userspace governor
> executes further, even if error is returned from sscanf,
> this will result in setting up wrong frequency value.
>
> Add proper error check to bail out if any error is returned.
>
> Signed-off-by: Santosh Mardi <gsantosh@codeaurora.org>
> ---
> drivers/devfreq/governor_userspace.c | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/devfreq/governor_userspace.c b/drivers/devfreq/governor_userspace.c
> index 77028c2..1d0c9cc 100644
> --- a/drivers/devfreq/governor_userspace.c
> +++ b/drivers/devfreq/governor_userspace.c
> @@ -53,12 +53,15 @@ static ssize_t store_freq(struct device *dev, struct device_attribute *attr,
> mutex_lock(&devfreq->lock);
> data = devfreq->data;
>
> - sscanf(buf, "%lu", &wanted);
> + err = sscanf(buf, "%lu", &wanted);
> + if (err != 1)
> + goto out;
You can save this goto statement by moving this sscanf checking to
before taking the mutex.
> data->user_frequency = wanted;
> data->valid = true;
> err = update_devfreq(devfreq);
> if (err == 0)
> err = count;
> +out:
> mutex_unlock(&devfreq->lock);
> return err;
> }
> --
> 1.9.1
>
--
Qualcomm India Private Limited, on behalf of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a
Linux Foundation Collaborative Project
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] devfreq: add error check for sscanf in userspace governor
2017-08-08 6:56 ` Pavan Kondeti
@ 2017-08-08 19:26 ` Saravana Kannan
0 siblings, 0 replies; 6+ messages in thread
From: Saravana Kannan @ 2017-08-08 19:26 UTC (permalink / raw)
To: Pavan Kondeti
Cc: Santosh Mardi, myungjoo.ham, kyungmin.park, rafael.j.wysocki,
cw00.choi, linux-pm, LKML, gsantosh, skannan, rgottimu
On 08/07/2017 11:56 PM, Pavan Kondeti wrote:
> Hi Santosh,
>
> On Mon, Aug 7, 2017 at 6:36 PM, Santosh Mardi <gsantosh@codeaurora.org> wrote:
>> store_freq function of devfreq userspace governor
>> executes further, even if error is returned from sscanf,
>> this will result in setting up wrong frequency value.
>>
>> Add proper error check to bail out if any error is returned.
>>
>> Signed-off-by: Santosh Mardi <gsantosh@codeaurora.org>
>> ---
>> drivers/devfreq/governor_userspace.c | 5 ++++-
>> 1 file changed, 4 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/devfreq/governor_userspace.c b/drivers/devfreq/governor_userspace.c
>> index 77028c2..1d0c9cc 100644
>> --- a/drivers/devfreq/governor_userspace.c
>> +++ b/drivers/devfreq/governor_userspace.c
>> @@ -53,12 +53,15 @@ static ssize_t store_freq(struct device *dev, struct device_attribute *attr,
>> mutex_lock(&devfreq->lock);
>> data = devfreq->data;
>>
>> - sscanf(buf, "%lu", &wanted);
>> + err = sscanf(buf, "%lu", &wanted);
Also, we could just use kstroul().
>> + if (err != 1)
>> + goto out;
>
> You can save this goto statement by moving this sscanf checking to
> before taking the mutex.
>
>> data->user_frequency = wanted;
>> data->valid = true;
>> err = update_devfreq(devfreq);
>> if (err == 0)
>> err = count;
>> +out:
>> mutex_unlock(&devfreq->lock);
>> return err;
>> }
>> --
>> 1.9.1
>>
-Saravana
--
Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project
^ permalink raw reply [flat|nested] 6+ messages in thread