# \[PATCH\]\[next\] HID: playstation: fix array size comparison (off-by-one)

- Subsystems: HID CORE LAYER, HID PLAYSTATION DRIVER, THE REST
- Maintainers: Jiri Kosina, Benjamin Tissoires, Roderick Colenbrander, Linus Torvalds
- List: linux-input
- 2 messages, 2 authors
- Page: https://ratatoskr.run/linux-input/2021/02/6270520/t

## \[PATCH\]\[next\] HID: playstation: fix array size comparison (off-by-one)

- From: Colin King \<hidden\>
- Date: 2021-02-15 17:33:47 
- Message: https://ratatoskr.run/linux-input/2021/02/6270520.md

```text
From: Colin Ian King <redacted>

The comparison of value with the array size ps_gamepad_hat_mapping
appears to be off-by-one. Fix this by using >= rather than > for the
size comparison.

Addresses-Coverity: ("Out-of-bounds read")
Fixes: bc2e15a9a022 ("HID: playstation: initial DualSense USB support.")
Signed-off-by: Colin Ian King <redacted>
---
 drivers/hid/hid-playstation.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/hid/hid-playstation.c b/drivers/hid/hid-playstation.c
index 408b651174cf..568a3a067c88 100644
--- a/drivers/hid/hid-playstation.c
+++ b/drivers/hid/hid-playstation.c
@@ -1064,7 +1064,7 @@ static int dualsense_parse_report(struct ps_device *ps_dev, struct hid_report *r
 	input_report_abs(ds->gamepad, ABS_RZ, ds_report->rz);
 
 	value = ds_report->buttons[0] & DS_BUTTONS0_HAT_SWITCH;
-	if (value > ARRAY_SIZE(ps_gamepad_hat_mapping))
+	if (value >= ARRAY_SIZE(ps_gamepad_hat_mapping))
 		value = 8; /* center */
 	input_report_abs(ds->gamepad, ABS_HAT0X, ps_gamepad_hat_mapping[value].x);
 	input_report_abs(ds->gamepad, ABS_HAT0Y, ps_gamepad_hat_mapping[value].y);
-- 
2.30.0

```

## Re: \[PATCH\]\[next\] HID: playstation: fix array size comparison (off-by-one)

- From: Benjamin Tissoires \<hidden\>
- Date: 2021-02-17 20:06:26 
- Message: https://ratatoskr.run/linux-input/2021/02/6272310.md

```text
On Mon, Feb 15, 2021 at 5:39 PM Colin King [ref] wrote:
>
> From: Colin Ian King <redacted>
>
> The comparison of value with the array size ps_gamepad_hat_mapping
> appears to be off-by-one. Fix this by using >= rather than > for the
> size comparison.
>
> Addresses-Coverity: ("Out-of-bounds read")
> Fixes: bc2e15a9a022 ("HID: playstation: initial DualSense USB support.")
> Signed-off-by: Colin Ian King <redacted>
> ---

Good catch.

Applied to for-5.12/playstation-v2

Cheers,
Benjamin

>  drivers/hid/hid-playstation.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/hid/hid-playstation.c b/drivers/hid/hid-playstation.c
> index 408b651174cf..568a3a067c88 100644
> --- a/drivers/hid/hid-playstation.c
> +++ b/drivers/hid/hid-playstation.c
> @@ -1064,7 +1064,7 @@ static int dualsense_parse_report(struct ps_device *ps_dev, struct hid_report *r
>         input_report_abs(ds->gamepad, ABS_RZ, ds_report->rz);
>
>         value = ds_report->buttons[0] & DS_BUTTONS0_HAT_SWITCH;
> -       if (value > ARRAY_SIZE(ps_gamepad_hat_mapping))
> +       if (value >= ARRAY_SIZE(ps_gamepad_hat_mapping))
>                 value = 8; /* center */
>         input_report_abs(ds->gamepad, ABS_HAT0X, ps_gamepad_hat_mapping[value].x);
>         input_report_abs(ds->gamepad, ABS_HAT0Y, ps_gamepad_hat_mapping[value].y);
> --
> 2.30.0
>

```