From: Dan Carpenter <dan.carpenter@oracle.com>
Date: Fri, 21 Jan 2022 11:55:43 +0000 (+0300)
Subject: hwmon: (adt7470) Prevent divide by zero in adt7470_fan_write()
X-Git-Tag: v6.6.17~8307^2~1
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=c1ec0cabc36718efc7fe8b4157d41b82d08ec1d2;p=platform%2Fkernel%2Flinux-rpi.git

hwmon: (adt7470) Prevent divide by zero in adt7470_fan_write()

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>
---

diff --git a/drivers/hwmon/adt7470.c b/drivers/hwmon/adt7470.c
index d519aca..fb6d14d 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);