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    Subject[PATCH 5.16 159/200] hwmon: (adt7470) Prevent divide by zero in adt7470_fan_write()
    Date
    From: Dan Carpenter <dan.carpenter@oracle.com>

    [ Upstream commit c1ec0cabc36718efc7fe8b4157d41b82d08ec1d2 ]

    The "val" variable is controlled by the user and comes from
    hwmon_attr_store(). The FAN_RPM_TO_PERIOD() macro divides by "val"
    so a zero will crash the system. Check for that and return -EINVAL.
    Negatives are also invalid so return -EINVAL for those too.

    Fixes: fc958a61ff6d ("hwmon: (adt7470) Convert to devm_hwmon_device_register_with_info API")
    Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
    Signed-off-by: Guenter Roeck <linux@roeck-us.net>
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    drivers/hwmon/adt7470.c | 3 +++
    1 file changed, 3 insertions(+)

    diff --git a/drivers/hwmon/adt7470.c b/drivers/hwmon/adt7470.c
    index d519aca4a9d64..fb6d14d213a18 100644
    --- a/drivers/hwmon/adt7470.c
    +++ b/drivers/hwmon/adt7470.c
    @@ -662,6 +662,9 @@ static int adt7470_fan_write(struct device *dev, u32 attr, int channel, long val
    struct adt7470_data *data = dev_get_drvdata(dev);
    int err;

    + if (val <= 0)
    + return -EINVAL;
    +
    val = FAN_RPM_TO_PERIOD(val);
    val = clamp_val(val, 1, 65534);

    --
    2.34.1


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