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authorAxel Lin <axel.lin@ingics.com>2014-08-05 10:08:31 +0800
committerGuenter Roeck <linux@roeck-us.net>2014-08-05 17:48:52 -0700
commit5b963089161b8fb244889c972edf553b9d737545 (patch)
treed512add2afcc03879f3cb2581a2f5a32db6a0c93
parentf4d33337eac4007793ca11fd1ab68d91ce7aa762 (diff)
downloadlinux-5b963089161b8fb244889c972edf553b9d737545.tar.bz2
hwmon: (lm92) Prevent overflow problem when writing large limits
On platforms with sizeof(int) < sizeof(long), writing a temperature limit larger than MAXINT will result in unpredictable limit values written to the chip. Avoid auto-conversion from long to int to fix the problem. The hysteresis temperature range depends on the value of data->temp[attr->index], since val is subtracted from it. Use a wider clamp, [-120000, 220000] should do to cover the possible range. Also add missing TEMP_TO_REG() on writes into cached hysteresis value. Also uses clamp_val to simplify the code a bit. Signed-off-by: Axel Lin <axel.lin@ingics.com> [Guenter Roeck: Fixed double TEMP_TO_REG on hysteresis updates] Cc: stable@vger.kernel.org Signed-off-by: Guenter Roeck <linux@roeck-us.net>
-rw-r--r--drivers/hwmon/lm92.c13
1 files changed, 6 insertions, 7 deletions
diff --git a/drivers/hwmon/lm92.c b/drivers/hwmon/lm92.c
index d2060e245ff5..cfaf70b9cba7 100644
--- a/drivers/hwmon/lm92.c
+++ b/drivers/hwmon/lm92.c
@@ -74,12 +74,9 @@ static inline int TEMP_FROM_REG(s16 reg)
return reg / 8 * 625 / 10;
}
-static inline s16 TEMP_TO_REG(int val)
+static inline s16 TEMP_TO_REG(long val)
{
- if (val <= -60000)
- return -60000 * 10 / 625 * 8;
- if (val >= 160000)
- return 160000 * 10 / 625 * 8;
+ val = clamp_val(val, -60000, 160000);
return val * 10 / 625 * 8;
}
@@ -206,10 +203,12 @@ static ssize_t set_temp_hyst(struct device *dev,
if (err)
return err;
+ val = clamp_val(val, -120000, 220000);
mutex_lock(&data->update_lock);
- data->temp[t_hyst] = TEMP_FROM_REG(data->temp[attr->index]) - val;
+ data->temp[t_hyst] =
+ TEMP_TO_REG(TEMP_FROM_REG(data->temp[attr->index]) - val);
i2c_smbus_write_word_swapped(client, LM92_REG_TEMP_HYST,
- TEMP_TO_REG(data->temp[t_hyst]));
+ data->temp[t_hyst]);
mutex_unlock(&data->update_lock);
return count;
}