[PATCH 4.8 067/125] iio: ad5755: fix off-by-one on devnr limit check

[Greg Kroah-Hartman]

4.8-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Colin Ian King <colin.king@xxxxxxxxxxxxx>

commit 9d47964bfd471f0dd4c89f28556aec68bffa0020 upstream.

The comparison for devnr limits is off-by-one, the current check
allows 0 to AD5755_NUM_CHANNELS and the limit should be in fact
0 to AD5755_NUM_CHANNELS - 1.  This can lead to an out of bounds
write to pdata->dac[devnr]. Fix this by replacing > with >= on the
comparison.

Signed-off-by: Colin Ian King <colin.king@xxxxxxxxxxxxx>
Fixes: c947459979c6 ("iio: ad5755: add support for dt bindings")
Signed-off-by: Jonathan Cameron <jic23@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/iio/dac/ad5755.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/iio/dac/ad5755.c
+++ b/drivers/iio/dac/ad5755.c
@@ -655,7 +655,7 @@ static struct ad5755_platform_data *ad57
 
 	devnr = 0;
 	for_each_child_of_node(np, pp) {
-		if (devnr > AD5755_NUM_CHANNELS) {
+		if (devnr >= AD5755_NUM_CHANNELS) {
 			dev_err(dev,
 				"There is to many channels defined in DT\n");
 			goto error_out;