[PATCH v2] iio: vadc: Fix potential dereference of NULL pointer

Yongzhi Liu
2022-05-19T10:54:59Z

The return value of vadc_get_channel() needs to be checked
to avoid use of NULL pointer. Fix this by adding the null
pointer check on prop.

Fixes: 0917de94c ("iio: vadc: Qualcomm SPMI PMIC voltage ADC driver")

Signed-off-by: Yongzhi Liu <lyz_cs@pku.edu.cn>
---
drivers/iio/adc/qcom-spmi-vadc.c | 23 ++++++++++++++++++++++-
1 file changed, 22 insertions(+), 1 deletion(-)

diff --git a/drivers/iio/adc/qcom-spmi-vadc.c b/drivers/iio/adc/qcom-spmi-vadc.c
index 34202ba..9fa61fb 100644
--- a/drivers/iio/adc/qcom-spmi-vadc.c
+++ b/drivers/iio/adc/qcom-spmi-vadc.c
@@ -358,14 +358,25 @@ static int vadc_measure_ref_points(struct vadc_priv *vadc)
vadc->graph[VADC_CALIB_ABSOLUTE].dx = VADC_ABSOLUTE_RANGE_UV;

prop = vadc_get_channel(vadc, VADC_REF_1250MV);
+ if (!prop) {
+ dev_err(vadc->dev, "Please define 1.25V channel\n");
+ ret = -ENODEV;
+ goto err;
+ }
ret = vadc_do_conversion(vadc, prop, &read_1);
if (ret)
goto err;

/* Try with buffered 625mV channel first */
prop = vadc_get_channel(vadc, VADC_SPARE1);
- if (!prop)
+ if (!prop) {
prop = vadc_get_channel(vadc, VADC_REF_625MV);
+ if (!prop) {
+ dev_err(vadc->dev, "Please define 0.625V channel\n");
+ ret = -ENODEV;
+ goto err;
+ }
+ }

ret = vadc_do_conversion(vadc, prop, &read_2);
if (ret)
@@ -381,11 +392,21 @@ static int vadc_measure_ref_points(struct vadc_priv *vadc)

/* Ratiometric calibration */
prop = vadc_get_channel(vadc, VADC_VDD_VADC);
+ if (!prop) {
+ dev_err(vadc->dev, "Please define VDD channel\n");
+ ret = -ENODEV;
+ goto err;
+ }
ret = vadc_do_conversion(vadc, prop, &read_1);
if (ret)
goto err;

prop = vadc_get_channel(vadc, VADC_GND_REF);
+ if (!prop) {
+ dev_err(vadc->dev, "Please define GND channel\n");
+ ret = -ENODEV;
+ goto err;
+ }
ret = vadc_do_conversion(vadc, prop, &read_2);
if (ret)
goto err;
--
2.7.4