1. Patchew
  2. linux
  3. View series

[PATCH v5] iio: adc: ad4030: fix invalid oversampling_ratio validation

Salah Triki posted 1 patch 3 weeks, 1 day ago 
drivers/iio/adc/ad4030.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)
[PATCH v5] iio: adc: ad4030: fix invalid oversampling_ratio validation
Posted by Salah Triki 3 weeks, 1 day ago 
In ad4030_set_avg_frame_len(), the logarithm is calculated before input
validation. Passing zero or negative values leads to an undefined result
from ilog2().

Validate that the input is strictly positive prior to computing its
logarithm.

Fixes: 949abd1ca5a4 ("iio: adc: ad4030: add averaging support")
Assisted-by: Claude:claude-sonnet-5
Signed-off-by: Salah Triki <salah.triki@gmail.com>
---
Changes in v5:
  - Split validation into two distinct checks with explanatory comments
  (per Andy Shevchenko and Nuno Sá).
  - Used 'avg_val < 1' to explicitly reject invalid values for ilog2()
  (per Andy Shevchenko and Nuno Sá).
  - Tightened commit log description.

Changes in v4:
  - Reordered local variables to enforce strict reversed Christmas tree layout
  (per Andy Shevchenko).
  - Rephrased commit log in plain English without C-specific terms
  (per Andy Shevchenko).
  - Converted AI assistance note into a formal Assisted-by tag
  (per Andy Shevchenko).

Changes in v3:
  - Dropped the !is_power_of_2() check to preserve standard IIO attribute
   rounding behavior, per feedback from David Lechner and Jonathan Cameron.

Changes in v2:
  - Added note stating the issue was identified with assistance from
  Claude AI and verified manually.
  - Removed initialization of avg_log2 at declaration.

 drivers/iio/adc/ad4030.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/drivers/iio/adc/ad4030.c b/drivers/iio/adc/ad4030.c
index 9c5f19321e3b..f1499b4792b5 100644
--- a/drivers/iio/adc/ad4030.c
+++ b/drivers/iio/adc/ad4030.c
@@ -746,14 +746,21 @@ static int ad4030_set_chan_calibbias(struct iio_dev *indio_dev,
 static int ad4030_set_avg_frame_len(struct iio_dev *dev, int avg_val)
 {
 	struct ad4030_state *st = iio_priv(dev);
-	unsigned int avg_log2 = ilog2(avg_val);
 	unsigned int last_avg_idx = ARRAY_SIZE(ad4030_average_modes) - 1;
+	unsigned int avg_log2;
 	int freq_hz;
 	int ret;
 
-	if (avg_val < 0 || avg_val > ad4030_average_modes[last_avg_idx])
+	/* Reject unsupported modes */
+	if (avg_val > ad4030_average_modes[last_avg_idx])
+		return -EINVAL;
+
+	/* Avoid invalid values for logarithm since it's undefined */
+	if (avg_val < 1)
 		return -EINVAL;
 
+	avg_log2 = ilog2(avg_val);
+
 	if (st->offload_trigger) {
 		/*
 		 * The sample averaging and sampling frequency configurations
-- 
2.43.0
Re: [PATCH v5] iio: adc: ad4030: fix invalid oversampling_ratio validation
Posted by Jonathan Cameron 2 weeks, 5 days ago 
On Thu,  3 Sep 2026 12:43:09 +0100
Salah Triki <salah.triki@gmail.com> wrote:

> In ad4030_set_avg_frame_len(), the logarithm is calculated before input
> validation. Passing zero or negative values leads to an undefined result
> from ilog2().
> 
> Validate that the input is strictly positive prior to computing its
> logarithm.
> 
> Fixes: 949abd1ca5a4 ("iio: adc: ad4030: add averaging support")
> Assisted-by: Claude:claude-sonnet-5
> Signed-off-by: Salah Triki <salah.triki@gmail.com>

Given it is an Analog Devices part and Nuno is usually quick to reply
I'm going to wait for a tag from them before picking this up.

Thanks

Jonathan

> ---
> Changes in v5:
>   - Split validation into two distinct checks with explanatory comments
>   (per Andy Shevchenko and Nuno Sá).
>   - Used 'avg_val < 1' to explicitly reject invalid values for ilog2()
>   (per Andy Shevchenko and Nuno Sá).
>   - Tightened commit log description.
> 
> Changes in v4:
>   - Reordered local variables to enforce strict reversed Christmas tree layout
>   (per Andy Shevchenko).
>   - Rephrased commit log in plain English without C-specific terms
>   (per Andy Shevchenko).
>   - Converted AI assistance note into a formal Assisted-by tag
>   (per Andy Shevchenko).
> 
> Changes in v3:
>   - Dropped the !is_power_of_2() check to preserve standard IIO attribute
>    rounding behavior, per feedback from David Lechner and Jonathan Cameron.
> 
> Changes in v2:
>   - Added note stating the issue was identified with assistance from
>   Claude AI and verified manually.
>   - Removed initialization of avg_log2 at declaration.
> 
>  drivers/iio/adc/ad4030.c | 11 +++++++++--
>  1 file changed, 9 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/iio/adc/ad4030.c b/drivers/iio/adc/ad4030.c
> index 9c5f19321e3b..f1499b4792b5 100644
> --- a/drivers/iio/adc/ad4030.c
> +++ b/drivers/iio/adc/ad4030.c
> @@ -746,14 +746,21 @@ static int ad4030_set_chan_calibbias(struct iio_dev *indio_dev,
>  static int ad4030_set_avg_frame_len(struct iio_dev *dev, int avg_val)
>  {
>  	struct ad4030_state *st = iio_priv(dev);
> -	unsigned int avg_log2 = ilog2(avg_val);
>  	unsigned int last_avg_idx = ARRAY_SIZE(ad4030_average_modes) - 1;
> +	unsigned int avg_log2;
>  	int freq_hz;
>  	int ret;
>  
> -	if (avg_val < 0 || avg_val > ad4030_average_modes[last_avg_idx])
> +	/* Reject unsupported modes */
> +	if (avg_val > ad4030_average_modes[last_avg_idx])
> +		return -EINVAL;
> +
> +	/* Avoid invalid values for logarithm since it's undefined */
> +	if (avg_val < 1)
>  		return -EINVAL;
>  
> +	avg_log2 = ilog2(avg_val);
> +
>  	if (st->offload_trigger) {
>  		/*
>  		 * The sample averaging and sampling frequency configurations
Re: [PATCH v5] iio: adc: ad4030: fix invalid oversampling_ratio validation
Posted by Jonathan Cameron 5 days, 3 hours ago 
On Sun, 6 Sep 2026 19:11:12 +0100
Jonathan Cameron <jic23@kernel.org> wrote:

> On Thu,  3 Sep 2026 12:43:09 +0100
> Salah Triki <salah.triki@gmail.com> wrote:
> 
> > In ad4030_set_avg_frame_len(), the logarithm is calculated before input
> > validation. Passing zero or negative values leads to an undefined result
> > from ilog2().
> > 
> > Validate that the input is strictly positive prior to computing its
> > logarithm.
> > 
> > Fixes: 949abd1ca5a4 ("iio: adc: ad4030: add averaging support")
> > Assisted-by: Claude:claude-sonnet-5
> > Signed-off-by: Salah Triki <salah.triki@gmail.com>  
> 
> Given it is an Analog Devices part and Nuno is usually quick to reply
> I'm going to wait for a tag from them before picking this up.

Nuno had looked at v4 and I don't think raised any particular
problems so I've applied this one to the fixes-togreg branch of iio.git
and marked it for stable.

Thanks
Jonathan

> 
> Thanks
> 
> Jonathan
> 
> > ---
> > Changes in v5:
> >   - Split validation into two distinct checks with explanatory comments
> >   (per Andy Shevchenko and Nuno Sá).
> >   - Used 'avg_val < 1' to explicitly reject invalid values for ilog2()
> >   (per Andy Shevchenko and Nuno Sá).
> >   - Tightened commit log description.
> > 
> > Changes in v4:
> >   - Reordered local variables to enforce strict reversed Christmas tree layout
> >   (per Andy Shevchenko).
> >   - Rephrased commit log in plain English without C-specific terms
> >   (per Andy Shevchenko).
> >   - Converted AI assistance note into a formal Assisted-by tag
> >   (per Andy Shevchenko).
> > 
> > Changes in v3:
> >   - Dropped the !is_power_of_2() check to preserve standard IIO attribute
> >    rounding behavior, per feedback from David Lechner and Jonathan Cameron.
> > 
> > Changes in v2:
> >   - Added note stating the issue was identified with assistance from
> >   Claude AI and verified manually.
> >   - Removed initialization of avg_log2 at declaration.
> > 
> >  drivers/iio/adc/ad4030.c | 11 +++++++++--
> >  1 file changed, 9 insertions(+), 2 deletions(-)
> > 
> > diff --git a/drivers/iio/adc/ad4030.c b/drivers/iio/adc/ad4030.c
> > index 9c5f19321e3b..f1499b4792b5 100644
> > --- a/drivers/iio/adc/ad4030.c
> > +++ b/drivers/iio/adc/ad4030.c
> > @@ -746,14 +746,21 @@ static int ad4030_set_chan_calibbias(struct iio_dev *indio_dev,
> >  static int ad4030_set_avg_frame_len(struct iio_dev *dev, int avg_val)
> >  {
> >  	struct ad4030_state *st = iio_priv(dev);
> > -	unsigned int avg_log2 = ilog2(avg_val);
> >  	unsigned int last_avg_idx = ARRAY_SIZE(ad4030_average_modes) - 1;
> > +	unsigned int avg_log2;
> >  	int freq_hz;
> >  	int ret;
> >  
> > -	if (avg_val < 0 || avg_val > ad4030_average_modes[last_avg_idx])
> > +	/* Reject unsupported modes */
> > +	if (avg_val > ad4030_average_modes[last_avg_idx])
> > +		return -EINVAL;
> > +
> > +	/* Avoid invalid values for logarithm since it's undefined */
> > +	if (avg_val < 1)
> >  		return -EINVAL;
> >  
> > +	avg_log2 = ilog2(avg_val);
> > +
> >  	if (st->offload_trigger) {
> >  		/*
> >  		 * The sample averaging and sampling frequency configurations  
> 
>
Re: [PATCH v5] iio: adc: ad4030: fix invalid oversampling_ratio validation
Posted by Andy Shevchenko 3 weeks, 1 day ago 
On Thu, Sep 03, 2026 at 12:43:09PM +0100, Salah Triki wrote:
> In ad4030_set_avg_frame_len(), the logarithm is calculated before input
> validation. Passing zero or negative values leads to an undefined result
> from ilog2().
> 
> Validate that the input is strictly positive prior to computing its
> logarithm.

Reviewed-by: Andy Shevchenko <andriy.shevchenko@intel.com>

...

> Assisted-by: Claude:claude-sonnet-5

Assisted-by: LLM
(Documentation was updated on this. No need to resend just for this, though.)

-- 
With Best Regards,
Andy Shevchenko

Patchew 2.1-devel-ea86937

© 2016 - 2026 Red Hat, Inc.