[PATCH 6.9 077/374] iio: adc: PAC1934: fix accessing out of bounds array index

Greg Kroah-Hartman
2024-06-06T14:08:50Z

From: Marius Cristea <marius.cristea@microchip.com>

[ Upstream commit 51fafb3cd7fcf4f4682693b4d2883e2a5bfffe33 ]

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@microchip.com>
Signed-off-by: Marius Cristea <marius.cristea@microchip.com>
Closes: https://lore.kernel.org/linux-iio/20240405-embellish-bonnet-ab5f10560d93@wendy/
Tested-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20240425114232.81390-1-marius.cristea@microchip.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
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 e0c2742da5236..8a0c357422121 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;
--
2.43.0