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hwmon: (dme1737) Fix overflows seen when writing into limit attributes

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Writes into voltage limit, temperature limit, temperature hysteresis,
and temperature zone attributes can overflow due to unclamped parameters
to multiplications, additions, and subtractions.

Cc: Juerg Haefliger <juergh@gmail.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
This commit is contained in:
Guenter Roeck 2016-12-27 14:15:05 -08:00
parent 53e678d75e
commit 07cc189d16
1 changed files with 16 additions and 12 deletions
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28
drivers/hwmon/dme1737.c
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@ -279,7 +279,8 @@ static inline int IN_FROM_REG(int reg, int nominal, int res)
static inline int IN_TO_REG(long val, int nominal)
{
return clamp_val((val * 192 + nominal / 2) / nominal, 0, 255);
val = clamp_val(val, 0, 255 * nominal / 192);
return DIV_ROUND_CLOSEST(val * 192, nominal);
}
/*
@ -295,7 +296,8 @@ static inline int TEMP_FROM_REG(int reg, int res)
static inline int TEMP_TO_REG(long val)
{
return clamp_val((val < 0 ? val - 500 : val + 500) / 1000, -128, 127);
val = clamp_val(val, -128000, 127000);
return DIV_ROUND_CLOSEST(val, 1000);
}
/* Temperature range */
@ -331,9 +333,10 @@ static inline int TEMP_HYST_FROM_REG(int reg, int ix)
return (((ix == 1) ? reg : reg >> 4) & 0x0f) * 1000;
}
static inline int TEMP_HYST_TO_REG(long val, int ix, int reg)
static inline int TEMP_HYST_TO_REG(int temp, long hyst, int ix, int reg)
{
int hyst = clamp_val((val + 500) / 1000, 0, 15);
hyst = clamp_val(hyst, temp - 15000, temp);
hyst = DIV_ROUND_CLOSEST(temp - hyst, 1000);
return (ix == 1) ? (reg & 0xf0) | hyst : (reg & 0x0f) | (hyst << 4);
}
@ -1022,7 +1025,9 @@ static ssize_t set_zone(struct device *dev, struct device_attribute *attr,
int ix = sensor_attr_2->index;
int fn = sensor_attr_2->nr;
long val;
int temp;
int err;
u8 reg;
err = kstrtol(buf, 10, &val);
if (err)
@ -1035,10 +1040,9 @@ static ssize_t set_zone(struct device *dev, struct device_attribute *attr,
data->zone_low[ix] = dme1737_read(data,
DME1737_REG_ZONE_LOW(ix));
/* Modify the temp hyst value */
data->zone_hyst[ix == 2] = TEMP_HYST_TO_REG(
TEMP_FROM_REG(data->zone_low[ix], 8) -
val, ix, dme1737_read(data,
DME1737_REG_ZONE_HYST(ix == 2)));
temp = TEMP_FROM_REG(data->zone_low[ix], 8);
reg = dme1737_read(data, DME1737_REG_ZONE_HYST(ix == 2));
data->zone_hyst[ix == 2] = TEMP_HYST_TO_REG(temp, val, ix, reg);
dme1737_write(data, DME1737_REG_ZONE_HYST(ix == 2),
data->zone_hyst[ix == 2]);
break;
@ -1055,10 +1059,10 @@ static ssize_t set_zone(struct device *dev, struct device_attribute *attr,
* Modify the temp range value (which is stored in the upper
* nibble of the pwm_freq register)
*/
data->pwm_freq[ix] = TEMP_RANGE_TO_REG(val -
TEMP_FROM_REG(data->zone_low[ix], 8),
dme1737_read(data,
DME1737_REG_PWM_FREQ(ix)));
temp = TEMP_FROM_REG(data->zone_low[ix], 8);
val = clamp_val(val, temp, temp + 80000);
reg = dme1737_read(data, DME1737_REG_PWM_FREQ(ix));
data->pwm_freq[ix] = TEMP_RANGE_TO_REG(val - temp, reg);
dme1737_write(data, DME1737_REG_PWM_FREQ(ix),
data->pwm_freq[ix]);
break;