hwmon: (lm85) Fix overflows seen when writing voltage limit attributes

Writes into voltage limit attributes can overflow due to an unbound
multiplication.

Reviewed-by: Jean Delvare <jdelvare@suse.de>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

diff --git a/drivers/hwmon/lm85.c b/drivers/hwmon/lm85.c
index 6ff773fcaefbece828fe3eb89f594fd71e532e13..29c8136ce9c50c5c90156cdb91915e642eabea35 100644 (file)
--- a/drivers/hwmon/lm85.c
+++ b/drivers/hwmon/lm85.c
@@ -136,7 +136,8 @@ static const int lm85_scaling[] = {  /* .001 Volts */
 #define SCALE(val, from, to)   (((val) * (to) + ((from) / 2)) / (from))
 
 #define INS_TO_REG(n, val)     \
-               clamp_val(SCALE(val, lm85_scaling[n], 192), 0, 255)
+               SCALE(clamp_val(val, 0, 255 * lm85_scaling[n] / 192), \
+                     lm85_scaling[n], 192)
 
 #define INSEXT_FROM_REG(n, val, ext)   \
                SCALE(((val) << 4) + (ext), 192 << 4, lm85_scaling[n])