What this patch does:
Current implementation of store_freq function in devfreq
userspace governor executes further, even if error is returned
from sscanf. This will result in setting up wrong frequency value.
This patch adds proper error check to bail out if
any error is returned.
Santosh Mardi (1):
devfreq: add error check for sscanf in userspace governor
drivers/devfreq/governor_userspace.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
--
1.9.1
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 <[email protected]>
---
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;
}
--
1.9.1
> 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 <[email protected]>
Acked-by: MyungJoo Ham <[email protected]>
> ---
> drivers/devfreq/governor_userspace.c | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
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 <[email protected]>
> ---
> 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 <[email protected]>
--
Best Regards,
Chanwoo Choi
Samsung Electronics
Hi Santosh,
On Mon, Aug 7, 2017 at 6:36 PM, Santosh Mardi <[email protected]> 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 <[email protected]>
> ---
> 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
On 08/07/2017 11:56 PM, Pavan Kondeti wrote:
> Hi Santosh,
>
> On Mon, Aug 7, 2017 at 6:36 PM, Santosh Mardi <[email protected]> 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 <[email protected]>
>> ---
>> 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