[PATCH 9/9] iio: adc: ti-ads7950: validate SPI match data

[Jiale Yao]

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

ti_ads7950_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 dereferencing the chip information.

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: ff0843ceb1fb ("iio: adc: ti-ads7950: remove chip_info[]")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Jiale Yao <yaojiale02@xxxxxxx>
---
 drivers/iio/adc/ti-ads7950.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/iio/adc/ti-ads7950.c b/drivers/iio/adc/ti-ads7950.c
index d27c1f2885fd..0d5708e0b831 100644
--- a/drivers/iio/adc/ti-ads7950.c
+++ b/drivers/iio/adc/ti-ads7950.c
@@ -527,8 +527,10 @@ static int ti_ads7950_probe(struct spi_device *spi)
 	st->spi = spi;
 
 	info = spi_get_device_match_data(spi);
+	if (!info)
+		return -ENODATA;
 
-	indio_dev->name = spi_get_device_id(spi)->name;
+	indio_dev->name = spi->modalias;
 	indio_dev->modes = INDIO_DIRECT_MODE;
 	indio_dev->channels = info->channels;
 	indio_dev->num_channels = info->num_channels;
-- 
2.34.1