4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Guenter Roeck <linux@xxxxxxxxxxxx>
commit c0d04e9112ad59d73f23f3b0f6726c5e798dfcbf upstream.
Fix overflows seen when writing voltage and temperature limit attributes.
The value passed to DIV_ROUND_CLOSEST() needs to be clamped, and the
value parameter passed to nct7802_write_fan_min() is an unsigned long.
Also, writing values larger than 2700000 into a fan limit attribute results
in writing 0 into the chip's limit registers. The exact behavior when
writing this value is unspecified. For consistency, report a limit of
1350000 if the chip register reads 0. This may be wrong, and the chip
behavior should be verified with the actual chip, but it is better than
reporting a value of 0 (which, when written, results in writing a value
of 0x1fff into the chip register).
Fixes: 3434f3783580 ("hwmon: Driver for Nuvoton NCT7802Y")
Reviewed-by: Jean Delvare <jdelvare@xxxxxxx>
Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/hwmon/nct7802.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
--- a/drivers/hwmon/nct7802.c
+++ b/drivers/hwmon/nct7802.c
@@ -259,13 +259,15 @@ static int nct7802_read_fan_min(struct n
ret = 0;
else if (ret)
ret = DIV_ROUND_CLOSEST(1350000U, ret);
+ else
+ ret = 1350000U;
abort:
mutex_unlock(&data->access_lock);
return ret;
}
static int nct7802_write_fan_min(struct nct7802_data *data, u8 reg_fan_low,
- u8 reg_fan_high, unsigned int limit)
+ u8 reg_fan_high, unsigned long limit)
{
int err;
@@ -326,8 +328,8 @@ static int nct7802_write_voltage(struct
int shift = 8 - REG_VOLTAGE_LIMIT_MSB_SHIFT[index - 1][nr];
int err;
+ voltage = clamp_val(voltage, 0, 0x3ff * nct7802_vmul[nr]);
voltage = DIV_ROUND_CLOSEST(voltage, nct7802_vmul[nr]);
- voltage = clamp_val(voltage, 0, 0x3ff);
mutex_lock(&data->access_lock);
err = regmap_write(data->regmap,
@@ -402,7 +404,7 @@ static ssize_t store_temp(struct device
if (err < 0)
return err;
- val = clamp_val(DIV_ROUND_CLOSEST(val, 1000), -128, 127);
+ val = DIV_ROUND_CLOSEST(clamp_val(val, -128000, 127000), 1000);
err = regmap_write(data->regmap, nr, val & 0xff);
return err ? : count;
--
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