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SubjectRe: [PATCH v2] HID: betop: fix slab-out-of-bounds Write in betop_probe
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On 8/22/21 4:43 PM, F.A.Sulaiman wrote:
> Syzbot reported slab-out-of-bounds Write bug in hid-betopff driver.
> The problem is the driver assumes the device must have an input report but
> some malicious devices violate this assumption.
>
> So this patch checks hid_device's input is non empty before it's been used.
>
> Reported-by: syzbot+07efed3bc5a1407bd742@syzkaller.appspotmail.com
> Signed-off-by: F.A. SULAIMAN <asha.16@itfac.mrt.ac.lk>
> ---
> drivers/hid/hid-betopff.c | 5 +++++
> 1 file changed, 5 insertions(+)
>
> diff --git a/drivers/hid/hid-betopff.c b/drivers/hid/hid-betopff.c
> index 0790fbd3fc9a..2d62bde21413 100644
> --- a/drivers/hid/hid-betopff.c
> +++ b/drivers/hid/hid-betopff.c
> @@ -116,6 +116,11 @@ static int betop_probe(struct hid_device *hdev, const struct hid_device_id *id)
> {
> int ret;
>
> + if (list_empty(&hdev->inputs)) {
> + hid_err(hdev, "no inputs found\n");
> + return -ENODEV;
> + }
> +
> if (id->driver_data)
> hdev->quirks |= HID_QUIRK_MULTI_INPUT;
>
>

I am still able to trigger reported slab-out-bound with this patch
applied, please move this sanity check inside betopff_init().


Jiri, does it make sense to add proper error handling of betopff_init()?
Nowadays betop_probe() just ignores betopff_init() return value. It
looks wrong to me.


I think, Asha can prepare a patch series with these 2 changes



With regards,
Pavel Skripkin

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