Re: [PATCH v1] iio: adc: PAC1934: fix accessing out of bounds array index

From: Conor Dooley
Date: Thu Apr 25 2024 - 08:23:15 EST


On Thu, Apr 25, 2024 at 02:42:32PM +0300, marius.cristea@xxxxxxxxxxxxx wrote:
> From: Marius Cristea <marius.cristea@xxxxxxxxxxxxx>
>
> Fix accessing out of bounds array index for average
> current and voltage measurements. The device itself has
> only 4 channels, but in sysfs there are "fake"
> channels for the average voltages and currents too.
>
> Fixes: 0fb528c8255b: "iio: adc: adding support for PAC193x"
> Reported-by: Conor Dooley <conor.dooley@xxxxxxxxxxxxx>
> Signed-off-by: Marius Cristea <marius.cristea@xxxxxxxxxxxxx>
> ---
> drivers/iio/adc/pac1934.c | 9 +++++++++
> 1 file changed, 9 insertions(+)
>
> diff --git a/drivers/iio/adc/pac1934.c b/drivers/iio/adc/pac1934.c
> index f751260605e4..456f12faa348 100644
> --- a/drivers/iio/adc/pac1934.c
> +++ b/drivers/iio/adc/pac1934.c
> @@ -787,6 +787,15 @@ static int pac1934_read_raw(struct iio_dev *indio_dev,
> s64 curr_energy;
> int ret, channel = chan->channel - 1;
>
> + /*
> + * For AVG the index should be between 5 to 8.
> + * To calculate PAC1934_CH_VOLTAGE_AVERAGE,
> + * respectively PAC1934_CH_CURRENT real index, we need
> + * to remove the added offset (PAC1934_MAX_NUM_CHANNELS).
> + */
> + if (channel >= PAC1934_MAX_NUM_CHANNELS)
> + channel = channel - PAC1934_MAX_NUM_CHANNELS;
> +
> ret = pac1934_retrieve_data(info, PAC1934_MIN_UPDATE_WAIT_TIME_US);
> if (ret < 0)
> return ret;
>
> base-commit: b80ad8e3cd2712b78b98804d1f59199680d8ed91
> --
> 2.34.1
>

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