diff mbox series

[v2,3/7] HID: lenovo: Check hid_get_drvdata() returns non NULL in lenovo_event()

Message ID 20210220122438.21857-4-hdegoede@redhat.com
State Superseded
Headers show
Series HID: lenovo: Mute LED handling fixes and improvements | expand

Commit Message

Hans de Goede Feb. 20, 2021, 12:24 p.m. UTC
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")
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
---
 drivers/hid/hid-lenovo.c | 3 +++
 1 file changed, 3 insertions(+)

Comments

Marek BehĂșn Feb. 21, 2021, 1:39 a.m. UTC | #1
Reviewed-by: Marek BehĂșn <kabel@kernel.org>
diff mbox series

Patch

diff --git a/drivers/hid/hid-lenovo.c b/drivers/hid/hid-lenovo.c
index 49b8767a8d30..f1868b5d9b58 100644
--- a/drivers/hid/hid-lenovo.c
+++ b/drivers/hid/hid-lenovo.c
@@ -502,6 +502,9 @@  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: