Commit b50aa496 authored by Dmitry Osipenko's avatar Dmitry Osipenko Committed by Guenter Roeck
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hwmon: (lm90) Prevent integer underflows of temperature calculations 



The min/max/crit and all other temperature values that are passed to
the driver are unlimited and value that is close to INT_MIN results in
integer underflow of the temperature calculations made by the driver
for LM99 sensor. Temperature hysteresis is among those values that need
to be limited, but limiting of hysteresis is independent from the sensor
version. Add the missing limits.

Signed-off-by: default avatarDmitry Osipenko <digetx@gmail.com>
Link: https://lore.kernel.org/r/20210623042231.16008-2-digetx@gmail.com


Signed-off-by: default avatarGuenter Roeck <linux@roeck-us.net>
parent 4c7f85a3

drivers/hwmon/lm90.c

+11 −2
Original line number Diff line number Diff line
@@ -1029,8 +1029,11 @@ static int lm90_set_temp11(struct lm90_data *data, int index, long val) 
	int err;



	/* +16 degrees offset for temp2 for the LM99 */

	if (data->kind == lm99 && index <= 2)

	if (data->kind == lm99 && index <= 2) {

		/* prevent integer underflow */

		val = max(val, -128000l);

		val -= 16000;

	}



	if (data->kind == adt7461 || data->kind == tmp451)

		data->temp11[index] = temp_to_u16_adt7461(data, val);
@@ -1089,8 +1092,11 @@ static int lm90_set_temp8(struct lm90_data *data, int index, long val) 
	int err;



	/* +16 degrees offset for temp2 for the LM99 */

	if (data->kind == lm99 && index == 3)

	if (data->kind == lm99 && index == 3) {

		/* prevent integer underflow */

		val = max(val, -128000l);

		val -= 16000;

	}



	if (data->kind == adt7461 || data->kind == tmp451)

		data->temp8[index] = temp_to_u8_adt7461(data, val);
@@ -1137,6 +1143,9 @@ static int lm90_set_temphyst(struct lm90_data *data, long val) 
	else

		temp = temp_from_s8(data->temp8[LOCAL_CRIT]);



	/* prevent integer underflow */

	val = max(val, -128000l);



	data->temp_hyst = hyst_to_reg(temp - val);

	err = i2c_smbus_write_byte_data(client, LM90_REG_W_TCRIT_HYST,

					data->temp_hyst);