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[PATCH] hwmon: asus_atk0110.c fix uninitialized data access

Started byArnd Bergmann <arnd@arndb.de>
First post2017-03-23 16:10 +0100
Last post2017-03-23 21:30 +0100
Articles 3 — 3 participants

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  [PATCH] hwmon: asus_atk0110.c fix uninitialized data access Arnd Bergmann <arnd@arndb.de> - 2017-03-23 16:10 +0100
    Re: [PATCH] hwmon: asus_atk0110.c fix uninitialized data access Luca Tettamanti <kronos.it@gmail.com> - 2017-03-23 16:40 +0100
    Re: [PATCH] hwmon: asus_atk0110.c fix uninitialized data access Guenter Roeck <linux@roeck-us.net> - 2017-03-23 21:30 +0100

#1607574 — [PATCH] hwmon: asus_atk0110.c fix uninitialized data access

FromArnd Bergmann <arnd@arndb.de>
Date2017-03-23 16:10 +0100
Subject[PATCH] hwmon: asus_atk0110.c fix uninitialized data access
Message-ID<tocxb-3SR-3@gated-at.bofh.it>
The latest gcc-7 snapshot adds a warning to point out that when
atk_read_value_old or atk_read_value_new fails, we copy
uninitialized data into sensor->cached_value:

drivers/hwmon/asus_atk0110.c: In function 'atk_input_show':
drivers/hwmon/asus_atk0110.c:651:26: error: 'value' may be used uninitialized in this function [-Werror=maybe-uninitialized]

Adding an error check avoids this. All versions of the driver
are affected.

Fixes: 2c03d07ad54d ("hwmon: Add Asus ATK0110 support")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/hwmon/asus_atk0110.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/hwmon/asus_atk0110.c b/drivers/hwmon/asus_atk0110.c
index cccef87963e0..975c43d446f8 100644
--- a/drivers/hwmon/asus_atk0110.c
+++ b/drivers/hwmon/asus_atk0110.c
@@ -646,6 +646,9 @@ static int atk_read_value(struct atk_sensor_data *sensor, u64 *value)
 		else
 			err = atk_read_value_new(sensor, value);
 
+		if (err)
+			return err;
+
 		sensor->is_valid = true;
 		sensor->last_updated = jiffies;
 		sensor->cached_value = *value;
-- 
2.9.0

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#1607633

FromLuca Tettamanti <kronos.it@gmail.com>
Date2017-03-23 16:40 +0100
Message-ID<tod0f-4a5-33@gated-at.bofh.it>
In reply to#1607574
On 23 March 2017 at 16:03, Arnd Bergmann <arnd@arndb.de> wrote:
> The latest gcc-7 snapshot adds a warning to point out that when
> atk_read_value_old or atk_read_value_new fails, we copy
> uninitialized data into sensor->cached_value:
>
> drivers/hwmon/asus_atk0110.c: In function 'atk_input_show':
> drivers/hwmon/asus_atk0110.c:651:26: error: 'value' may be used uninitialized in this function [-Werror=maybe-uninitialized]

Ops, thanks for catching this.

>
> Adding an error check avoids this. All versions of the driver
> are affected.
>
> Fixes: 2c03d07ad54d ("hwmon: Add Asus ATK0110 support")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Luca Tettamanti <kronos.it@gmail.com>


> ---
>  drivers/hwmon/asus_atk0110.c | 3 +++
>  1 file changed, 3 insertions(+)
>
> diff --git a/drivers/hwmon/asus_atk0110.c b/drivers/hwmon/asus_atk0110.c
> index cccef87963e0..975c43d446f8 100644
> --- a/drivers/hwmon/asus_atk0110.c
> +++ b/drivers/hwmon/asus_atk0110.c
> @@ -646,6 +646,9 @@ static int atk_read_value(struct atk_sensor_data *sensor, u64 *value)
>                 else
>                         err = atk_read_value_new(sensor, value);
>
> +               if (err)
> +                       return err;
> +
>                 sensor->is_valid = true;
>                 sensor->last_updated = jiffies;
>                 sensor->cached_value = *value;
> --
> 2.9.0
>

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#1607875

FromGuenter Roeck <linux@roeck-us.net>
Date2017-03-23 21:30 +0100
Message-ID<tohwS-7sz-17@gated-at.bofh.it>
In reply to#1607574
On Thu, Mar 23, 2017 at 04:03:11PM +0100, Arnd Bergmann wrote:
> The latest gcc-7 snapshot adds a warning to point out that when
> atk_read_value_old or atk_read_value_new fails, we copy
> uninitialized data into sensor->cached_value:
> 
> drivers/hwmon/asus_atk0110.c: In function 'atk_input_show':
> drivers/hwmon/asus_atk0110.c:651:26: error: 'value' may be used uninitialized in this function [-Werror=maybe-uninitialized]
> 
> Adding an error check avoids this. All versions of the driver
> are affected.
> 
Nice catch!

Applied, thanks.

Guenter

> Fixes: 2c03d07ad54d ("hwmon: Add Asus ATK0110 support")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
>  drivers/hwmon/asus_atk0110.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/hwmon/asus_atk0110.c b/drivers/hwmon/asus_atk0110.c
> index cccef87963e0..975c43d446f8 100644
> --- a/drivers/hwmon/asus_atk0110.c
> +++ b/drivers/hwmon/asus_atk0110.c
> @@ -646,6 +646,9 @@ static int atk_read_value(struct atk_sensor_data *sensor, u64 *value)
>  		else
>  			err = atk_read_value_new(sensor, value);
>  
> +		if (err)
> +			return err;
> +
>  		sensor->is_valid = true;
>  		sensor->last_updated = jiffies;
>  		sensor->cached_value = *value;
> -- 
> 2.9.0
> 

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