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

Yongzhi Liu <lyz_cs@pku.edu.cn> writes:

> 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(-)

Did you sent this to linux-wireless by mistake?

-- 
https://patchwork.kernel.org/project/linux-wireless/list/

https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches

> -----Original Messages-----
> From: "Kalle Valo" <kvalo@kernel.org>
> Sent Time: 2022-05-19 23:30:51 (Thursday)
> To: "Yongzhi Liu" <lyz_cs@pku.edu.cn>
> Cc: amitkarwar@gmail.com, ganapathi017@gmail.com, sharvari.harisangam@nxp.com, huxinming820@gmail.com, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, arend.vanspriel@broadcom.com, linux-wireless@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, fuyq@stu.pku.edu.cn
> Subject: Re: [PATCH v2] iio: vadc: Fix potential dereference of NULL pointer
> 
> Yongzhi Liu <lyz_cs@pku.edu.cn> writes:
> 
> > 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(-)
> 

I'm sorry to send this to linux-wireless by mistake. I will cautiously submit patches later.

> Did you sent this to linux-wireless by mistake?
> 
> -- 
> https://patchwork.kernel.org/project/linux-wireless/list/
> 
> https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches