[PATCH linux dev-4.10] hwmon (occ): Fix integer overflow in multiplication

[Christopher Bostic]

Reviewed-by: Christopher Bostic <cbostic at linux.vnet.ibm.com>


On 12/6/17 1:19 PM, Eddie James wrote:
> From: "Edward A. James" <eajames at us.ibm.com>
>
> Power values were overflowing INT_MAX when being converted to
> microwatts, even though the storage was sufficiently large (unsigned 64
> bit). Change literals to unsigned long long.
>
> Signed-off-by: Edward A. James <eajames at us.ibm.com>
> ---
>   drivers/hwmon/occ/common.c | 17 +++++++++--------
>   1 file changed, 9 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/hwmon/occ/common.c b/drivers/hwmon/occ/common.c
> index 3175e7b..a64f3db 100644
> --- a/drivers/hwmon/occ/common.c
> +++ b/drivers/hwmon/occ/common.c
> @@ -468,7 +468,7 @@ static ssize_t occ_show_power_1(struct device *dev,
>   				struct device_attribute *attr, char *buf)
>   {
>   	int rc;
> -	u32 val = 0;
> +	u64 val = 0;
>   	struct power_sensor_1 *power;
>   	struct occ *occ = dev_get_drvdata(dev);
>   	struct occ_sensors *sensors = &occ->sensors;
> @@ -491,11 +491,11 @@ static ssize_t occ_show_power_1(struct device *dev,
>   		val = get_unaligned_be32(&power->accumulator);
>   		break;
>   	case 3:
> -		val = get_unaligned_be16(&power->value) * 1000000;
> +		val = (u64)get_unaligned_be16(&power->value) * 1000000ULL;
>   		break;
>   	}
>
> -	return snprintf(buf, PAGE_SIZE - 1, "%u\n", val);
> +	return snprintf(buf, PAGE_SIZE - 1, "%llu\n", val);
>   }
>
>   static ssize_t occ_show_power_2(struct device *dev,
> @@ -525,7 +525,7 @@ static ssize_t occ_show_power_2(struct device *dev,
>   		val = get_unaligned_be64(&power->accumulator);
>   		break;
>   	case 3:
> -		val = get_unaligned_be16(&power->value) * 1000000;
> +		val = (u64)get_unaligned_be16(&power->value) * 1000000ULL;
>   		break;
>   	case 4:
>   		val = power->function_id;
> @@ -562,7 +562,8 @@ static ssize_t occ_show_power_a0(struct device *dev,
>   		val = get_unaligned_be16(&power->system.update_time);
>   		break;
>   	case 2:
> -		val = get_unaligned_be16(&power->system.value) * 1000000;
> +		val = (u64)get_unaligned_be16(&power->system.value) *
> +			1000000ULL;
>   		break;
>   	case 3:
>   		val = get_unaligned_be32(&power->system.update_tag);
> @@ -574,7 +575,7 @@ static ssize_t occ_show_power_a0(struct device *dev,
>   		val = get_unaligned_be16(&power->proc.update_time);
>   		break;
>   	case 6:
> -		val = get_unaligned_be16(&power->proc.value) * 1000000;
> +		val = (u64)get_unaligned_be16(&power->proc.value) * 1000000ULL;
>   		break;
>   	case 7:
>   		val = get_unaligned_be32(&power->proc.update_tag);
> @@ -583,7 +584,7 @@ static ssize_t occ_show_power_a0(struct device *dev,
>   		val = get_unaligned_be64(&power->proc.accumulator);
>   		break;
>   	case 9:
> -		val = get_unaligned_be16(&power->vdd.value) * 1000000;
> +		val = (u64)get_unaligned_be16(&power->vdd.value) * 1000000ULL;
>   		break;
>   	case 10:
>   		val = get_unaligned_be32(&power->vdd.update_tag);
> @@ -592,7 +593,7 @@ static ssize_t occ_show_power_a0(struct device *dev,
>   		val = get_unaligned_be64(&power->vdd.accumulator);
>   		break;
>   	case 12:
> -		val = get_unaligned_be16(&power->vdn.value) * 1000000;
> +		val = (u64)get_unaligned_be16(&power->vdn.value) * 1000000ULL;
>   		break;
>   	case 13:
>   		val = get_unaligned_be32(&power->vdn.update_tag);