[PATCH] iio: ssp_sensors: add more range checking in ssp_parse_dataframe()

[Dan Carpenter <dan.carpenter@oracle.com>]

The "idx" is validated at the start of the loop but it gets incremented
during the iteration so it needs to be checked again.

Fixes: 50dd64d57eee ("iio: common: ssp_sensors: Add sensorhub driver")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
---
 drivers/iio/common/ssp_sensors/ssp_spi.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/iio/common/ssp_sensors/ssp_spi.c b/drivers/iio/common/ssp_sensors/ssp_spi.c
index 4864c38b8d1c..387551eac184 100644
--- a/drivers/iio/common/ssp_sensors/ssp_spi.c
+++ b/drivers/iio/common/ssp_sensors/ssp_spi.c
@@ -273,6 +273,8 @@ static int ssp_parse_dataframe(struct ssp_data *data, char *dataframe, int len)
 	for (idx = 0; idx < len;) {
 		switch (dataframe[idx++]) {
 		case SSP_MSG2AP_INST_BYPASS_DATA:
+			if (idx >= len)
+				return -EPROTO;
 			sd = dataframe[idx++];
 			if (sd < 0 || sd >= SSP_SENSOR_MAX) {
 				dev_err(SSP_DEV,
@@ -282,10 +284,13 @@ static int ssp_parse_dataframe(struct ssp_data *data, char *dataframe, int len)
 
 			if (indio_devs[sd]) {
 				spd = iio_priv(indio_devs[sd]);
-				if (spd->process_data)
+				if (spd->process_data) {
+					if (idx >= len)
+						return -EPROTO;
 					spd->process_data(indio_devs[sd],
 							  &dataframe[idx],
 							  data->timestamp);
+				}
 			} else {
 				dev_err(SSP_DEV, "no client for frame\n");
 			}
@@ -293,6 +298,8 @@ static int ssp_parse_dataframe(struct ssp_data *data, char *dataframe, int len)
 			idx += ssp_offset_map[sd];
 			break;
 		case SSP_MSG2AP_INST_DEBUG_DATA:
+			if (idx >= len)
+				return -EPROTO;
 			sd = ssp_print_mcu_debug(dataframe, &idx, len);
 			if (sd) {
 				dev_err(SSP_DEV,
-- 
2.20.1