Re: [PATCH v2] HID: betop: fix slab-out-of-bounds Write in betop_probe
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From: Pavel Skripkin <hidden>
Date: 2021-08-22 16:01:45
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On 8/22/21 4:43 PM, F.A.Sulaiman wrote:
quoted hunk ↗ jump to hunk
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 <redacted> --- 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