[PATCH 6/9] iio: adc: ti-adc128s052: validate SPI match data

[Jiale Yao]

SPI driver_override allows a device to bind to this driver without
matching either the firmware tables or SPI device ID table. In that
case, spi_get_device_match_data() returns NULL.

adc128_probe() also obtains the IIO device name by dereferencing the
result of spi_get_device_id(), which is NULL on the same override path.
The probe can therefore crash before it reaches the match data access.

Commit 572a00852635 ("iio: dac: ad5686: missing NULL check on match
data") fixed the same driver_override issue in another SPI driver.
Reject devices without match data and use the always available SPI
modalias for the IIO device name.

Fixes: d5f0da0c6972 ("iio: adc: ti-adc128s052: Switch to use spi_get_device_match_data()")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Jiale Yao <yaojiale02@xxxxxxx>
---
 drivers/iio/adc/ti-adc128s052.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/iio/adc/ti-adc128s052.c b/drivers/iio/adc/ti-adc128s052.c
index 1899813c1aee..f9a995ff403e 100644
--- a/drivers/iio/adc/ti-adc128s052.c
+++ b/drivers/iio/adc/ti-adc128s052.c
@@ -195,12 +195,14 @@ static int adc128_probe(struct spi_device *spi)
 	adc = iio_priv(indio_dev);
 	adc->spi = spi;
 
-	indio_dev->name = spi_get_device_id(spi)->name;
+	config = spi_get_device_match_data(spi);
+	if (!config)
+		return -ENODATA;
+
+	indio_dev->name = spi->modalias;
 	indio_dev->modes = INDIO_DIRECT_MODE;
 	indio_dev->info = &adc128_info;
 
-	config = spi_get_device_match_data(spi);
-
 	indio_dev->channels = config->channels;
 	indio_dev->num_channels = config->num_channels;
 
-- 
2.34.1