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From:   Benjamin Tissoires <benjamin.tissoires@redhat.com>
Date:   Wed, 17 Feb 2021 21:04:38 +0100
Message-ID: <CAO-hwJ+P=jH3ByHdab=qmrOWupnq-fiA0UR8mdHF1pQAuEqbAw@mail.gmail.com>
Subject: Re: [PATCH][next] HID: playstation: fix array size comparison (off-by-one)
To:     Colin King <colin.king@canonical.com>
Cc:     Roderick Colenbrander <roderick.colenbrander@sony.com>,
        Jiri Kosina <jikos@kernel.org>,
        =?UTF-8?B?QmFybmFiw6FzIFDFkWN6ZQ==?= <pobrn@protonmail.com>,
        "open list:HID CORE LAYER" <linux-input@vger.kernel.org>,
        kernel-janitors@vger.kernel.org,
        lkml <linux-kernel@vger.kernel.org>
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On Mon, Feb 15, 2021 at 5:39 PM Colin King <colin.king@canonical.com> wrote:
>
> From: Colin Ian King <colin.king@canonical.com>
>
> 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 <colin.king@canonical.com>
> ---

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
>