From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Axel Lin , Guenter Roeck Subject: [PATCH 3.16 047/125] hwmon: (lm92) Prevent overflow problem when writing large limits Date: Wed, 3 Sep 2014 15:06:44 -0700 Message-Id: <20140903220625.060915740@linuxfoundation.org> In-Reply-To: <20140903220623.649748296@linuxfoundation.org> References: <20140903220623.649748296@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.16-stable review patch. If anyone has any objections, please let me know. ------------------ From: Axel Lin commit 5b963089161b8fb244889c972edf553b9d737545 upstream. 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 [Guenter Roeck: Fixed double TEMP_TO_REG on hysteresis updates] Signed-off-by: Guenter Roeck Signed-off-by: Greg Kroah-Hartman --- drivers/hwmon/lm92.c | 13 ++++++------- 1 file changed, 6 insertions(+), 7 deletions(-) --- 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 devi 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; }