iio: inkern: add error case in iio_channel_get()

 The datasheet name is defined in the IIO driver.
 On the other hand, the adc_channel_label is configured in
 the platform side.
 If the datasheet name is not matched with any adc_channel_label,
 the iio_channel_get() should be returned as error for preventing
 invalid channel data access.

 This can be handled either way.
 (a) checking null data when using it : in the xxx_read_raw()
 or
 (b) error returns when the channel is requested : this patch

 The IIO consumer can't use the channel with invalid channel spec.
 Therefore case (b) is more reasonable.

Signed-off-by: Milo(Woogyom) Kim <milo.kim@ti.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

1 files changed, 10 insertions, 1 deletions

diff --git a/drivers/iio/inkern.c b/drivers/iio/inkern.c
index 028c657f8da3..d539e1e297ba 100644
--- a/drivers/iio/inkern.c
+++ b/drivers/iio/inkern.c
@@ -136,12 +136,21 @@ struct iio_channel *iio_channel_get(const char *name, const char *channel_name)
 
         channel->indio_dev = c->indio_dev;
 
-        if (c->map->adc_channel_label)
+        if (c->map->adc_channel_label) {
                 channel->channel =
                         iio_chan_spec_from_name(channel->indio_dev,
                                                 c->map->adc_channel_label);
 
+                if (channel->channel == NULL)
+                        goto error_no_chan;
+        }
+
         return channel;
+
+error_no_chan:
+        iio_device_put(c->indio_dev);
+        kfree(channel);
+        return ERR_PTR(-EINVAL);
 }
 EXPORT_SYMBOL_GPL(iio_channel_get);