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iio: chemical: bme680: Fix overflows in compensate() functions

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commit fdd478c3ae98c3f13628e110dce9b6cfb0d9b3c8 upstream.

There are cases in the compensate functions of the driver that
there could be overflows of variables due to bit shifting ops.
These implications were initially discussed here [1] and they
were mentioned in log message of Commit 1b3bd8592780 ("iio:
chemical: Add support for Bosch BME680 sensor").

[1]: https://lore.kernel.org/linux-iio/20180728114028.3c1bbe81@archlinux/

Fixes: 1b3bd8592780 ("iio: chemical: Add support for Bosch BME680 sensor")
Signed-off-by: Vasileios Amoiridis <vassilisamir@gmail.com>
Link: https://lore.kernel.org/r/20240606212313.207550-4-vassilisamir@gmail.com
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Vasileios Amoiridis 2024-06-06 23:22:55 +02:00 committed by Greg Kroah-Hartman
parent 2edd0078e3
commit 7a13d13576
1 changed files with 6 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

12
drivers/iio/chemical/bme680_core.c
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@ -342,10 +342,10 @@ static s16 bme680_compensate_temp(struct bme680_data *data,
if (!calib->par_t2)
bme680_read_calib(data, calib);
var1 = (adc_temp >> 3) - (calib->par_t1 << 1);
var1 = (adc_temp >> 3) - ((s32)calib->par_t1 << 1);
var2 = (var1 * calib->par_t2) >> 11;
var3 = ((var1 >> 1) * (var1 >> 1)) >> 12;
var3 = (var3 * (calib->par_t3 << 4)) >> 14;
var3 = (var3 * ((s32)calib->par_t3 << 4)) >> 14;
data->t_fine = var2 + var3;
calc_temp = (data->t_fine * 5 + 128) >> 8;
@ -368,9 +368,9 @@ static u32 bme680_compensate_press(struct bme680_data *data,
var1 = (data->t_fine >> 1) - 64000;
var2 = ((((var1 >> 2) * (var1 >> 2)) >> 11) * calib->par_p6) >> 2;
var2 = var2 + (var1 * calib->par_p5 << 1);
var2 = (var2 >> 2) + (calib->par_p4 << 16);
var2 = (var2 >> 2) + ((s32)calib->par_p4 << 16);
var1 = (((((var1 >> 2) * (var1 >> 2)) >> 13) *
(calib->par_p3 << 5)) >> 3) +
((s32)calib->par_p3 << 5)) >> 3) +
((calib->par_p2 * var1) >> 1);
var1 = var1 >> 18;
var1 = ((32768 + var1) * calib->par_p1) >> 15;
@ -388,7 +388,7 @@ static u32 bme680_compensate_press(struct bme680_data *data,
var3 = ((press_comp >> 8) * (press_comp >> 8) *
(press_comp >> 8) * calib->par_p10) >> 17;
press_comp += (var1 + var2 + var3 + (calib->par_p7 << 7)) >> 4;
press_comp += (var1 + var2 + var3 + ((s32)calib->par_p7 << 7)) >> 4;
return press_comp;
}
@ -414,7 +414,7 @@ static u32 bme680_compensate_humid(struct bme680_data *data,
(((temp_scaled * ((temp_scaled * calib->par_h5) / 100))
>> 6) / 100) + (1 << 14))) >> 10;
var3 = var1 * var2;
var4 = calib->par_h6 << 7;
var4 = (s32)calib->par_h6 << 7;
var4 = (var4 + ((temp_scaled * calib->par_h7) / 100)) >> 4;
var5 = ((var3 >> 14) * (var3 >> 14)) >> 10;
var6 = (var4 * var5) >> 1;