| From 4d76ce13b24da8b795a96c8384cc3be0e5939f8a Mon Sep 17 00:00:00 2001 |
| From: Sasha Levin <sashal@kernel.org> |
| Date: Sun, 4 Apr 2021 10:04:26 +0200 |
| Subject: HID: lenovo: Check hid_get_drvdata() returns non NULL in |
| lenovo_event() |
| MIME-Version: 1.0 |
| Content-Type: text/plain; charset=UTF-8 |
| Content-Transfer-Encoding: 8bit |
| |
| From: Hans de Goede <hdegoede@redhat.com> |
| |
| [ Upstream commit 34348a8661e3cd67dcf6938f08c8bb77522301f7 ] |
| |
| The HID lenovo probe function only attaches drvdata to one of the |
| USB interfaces, but lenovo_event() will get called for all USB interfaces |
| to which hid-lenovo is bound. |
| |
| This allows a malicious device to fake being a device handled by |
| hid-lenovo, which generates events for which lenovo_event() has |
| special handling (and thus dereferences hid_get_drvdata()) on another |
| interface triggering a NULL pointer exception. |
| |
| Add a check for hid_get_drvdata() returning NULL, avoiding this |
| possible NULL pointer exception. |
| |
| Fixes: bc04b37ea0ec ("HID: lenovo: Add ThinkPad 10 Ultrabook Keyboard support") |
| Reviewed-by: Marek Behรบn <kabel@kernel.org> |
| Signed-off-by: Hans de Goede <hdegoede@redhat.com> |
| Signed-off-by: Jiri Kosina <jkosina@suse.cz> |
| Signed-off-by: Sasha Levin <sashal@kernel.org> |
| --- |
| drivers/hid/hid-lenovo.c | 3 +++ |
| 1 file changed, 3 insertions(+) |
| |
| diff --git a/drivers/hid/hid-lenovo.c b/drivers/hid/hid-lenovo.c |
| index ee175ab54281..b2596ed37880 100644 |
| --- a/drivers/hid/hid-lenovo.c |
| +++ b/drivers/hid/hid-lenovo.c |
| @@ -508,6 +508,9 @@ static int lenovo_event_cptkbd(struct hid_device *hdev, |
| static int lenovo_event(struct hid_device *hdev, struct hid_field *field, |
| struct hid_usage *usage, __s32 value) |
| { |
| + if (!hid_get_drvdata(hdev)) |
| + return 0; |
| + |
| switch (hdev->product) { |
| case USB_DEVICE_ID_LENOVO_CUSBKBD: |
| case USB_DEVICE_ID_LENOVO_CBTKBD: |
| -- |
| 2.30.2 |
| |
