From 7a13d1357658d3a3c1cd7b3b9543c805a6e5e6e9 Mon Sep 17 00:00:00 2001 From: Vasileios Amoiridis Date: Thu, 6 Jun 2024 23:22:55 +0200 Subject: [PATCH] iio: chemical: bme680: Fix overflows in compensate() functions 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 Link: https://lore.kernel.org/r/20240606212313.207550-4-vassilisamir@gmail.com Cc: Signed-off-by: Jonathan Cameron Signed-off-by: Greg Kroah-Hartman --- drivers/iio/chemical/bme680_core.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/drivers/iio/chemical/bme680_core.c b/drivers/iio/chemical/bme680_core.c index c37d32e4d859..110841905609 100644 --- a/drivers/iio/chemical/bme680_core.c +++ b/drivers/iio/chemical/bme680_core.c @@ -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;