[PATCH] drivers/hid: avoid invalid denominator

From: Henry Castro
Date: Sun Apr 11 2021 - 11:07:42 EST


Avoid a potential panic in case wrong denominator
is given.

Signed-off-by: Henry Castro <hcvcastro@xxxxxxxxx>
---
drivers/hid/hid-sony.c | 13 +++++++++----
1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/drivers/hid/hid-sony.c b/drivers/hid/hid-sony.c
index 8319b0ce385a..67b45d82cc3b 100644
--- a/drivers/hid/hid-sony.c
+++ b/drivers/hid/hid-sony.c
@@ -1134,11 +1134,16 @@ static void dualshock4_parse_report(struct sony_sc *sc, u8 *rd, int size)
* Note: we swap numerator 'x' and 'numer' in mult_frac for
* precision reasons so we don't need 64-bit.
*/
- int calib_data = mult_frac(calib->sens_numer,
- raw_data - calib->bias,
- calib->sens_denom);
+ if (calib->sens_denom != 0) {
+ int calib_data = mult_frac(calib->sens_numer,
+ raw_data - calib->bias,
+ calib->sens_denom);
+
+ input_report_abs(sc->sensor_dev, calib->abs_code, calib_data);
+ } else {
+ hid_warn(sc->hdev, "DualShock 4 parse report, avoid invalid denominator");
+ }

- input_report_abs(sc->sensor_dev, calib->abs_code, calib_data);
offset += 2;
}
input_sync(sc->sensor_dev);
--
2.20.1