Re: [PATCH][next] hwmon: (mlxreg-fan): Fix out of bounds read on array fan->pwm

From: Guenter Roeck
Date: Thu Sep 23 2021 - 21:06:09 EST


On Mon, Sep 20, 2021 at 07:09:21PM +0100, Colin King wrote:
> From: Colin Ian King <colin.king@xxxxxxxxxxxxx>
>
> Array fan->pwm[] is MLXREG_FAN_MAX_PWM elements in size, however the
> for-loop has a off-by-one error causing index i to be out of range
> causing an out of bounds read on the array. Fix this by replacing
> the <= operator with < in the for-loop.
>
> Addresses-Coverity: ("Out-of-bounds read")
> Fixes: 35edbaab3bbf ("hwmon: (mlxreg-fan) Extend driver to support multiply cooling devices")
> Signed-off-by: Colin Ian King <colin.king@xxxxxxxxxxxxx>

Applied.

Thanks,
Guenter

> ---
> drivers/hwmon/mlxreg-fan.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/hwmon/mlxreg-fan.c b/drivers/hwmon/mlxreg-fan.c
> index 35228ed112d7..feab9ec6a6ca 100644
> --- a/drivers/hwmon/mlxreg-fan.c
> +++ b/drivers/hwmon/mlxreg-fan.c
> @@ -554,7 +554,7 @@ static int mlxreg_fan_cooling_config(struct device *dev, struct mlxreg_fan *fan)
> {
> int i, j;
>
> - for (i = 0; i <= MLXREG_FAN_MAX_PWM; i++) {
> + for (i = 0; i < MLXREG_FAN_MAX_PWM; i++) {
> struct mlxreg_fan_pwm *pwm = &fan->pwm[i];
>
> if (!pwm->connected)