HID: Fix assumption that devices have inputs
The syzbot fuzzer found a slab-out-of-bounds write bug in the hid-gaff
driver. The problem is caused by the driver's assumption that the
device must have an input report. While this will be true for all
normal HID input devices, a suitably malicious device can violate the
assumption.
The same assumption is present in over a dozen other HID drivers.
This patch fixes them by checking that the list of hid_inputs for the
hid_device is nonempty before allowing it to be used.
Reported-and-tested-by: [email protected]
Signed-off-by: Alan Stern <[email protected]>
CC: <[email protected]>
Signed-off-by: Benjamin Tissoires <[email protected]>
diff --git a/drivers/hid/hid-logitech-hidpp.c b/drivers/hid/hid-logitech-hidpp.c
index 0179f7e..1ac1ecc 100644
--- a/drivers/hid/hid-logitech-hidpp.c
+++ b/drivers/hid/hid-logitech-hidpp.c
@@ -2084,8 +2084,8 @@ static void hidpp_ff_destroy(struct ff_device *ff)
static int hidpp_ff_init(struct hidpp_device *hidpp, u8 feature_index)
{
struct hid_device *hid = hidpp->hid_dev;
- struct hid_input *hidinput = list_entry(hid->inputs.next, struct hid_input, list);
- struct input_dev *dev = hidinput->input;
+ struct hid_input *hidinput;
+ struct input_dev *dev;
const struct usb_device_descriptor *udesc = &(hid_to_usb_dev(hid)->descriptor);
const u16 bcdDevice = le16_to_cpu(udesc->bcdDevice);
struct ff_device *ff;
@@ -2094,6 +2094,13 @@ static int hidpp_ff_init(struct hidpp_device *hidpp, u8 feature_index)
int error, j, num_slots;
u8 version;
+ if (list_empty(&hid->inputs)) {
+ hid_err(hid, "no inputs found\n");
+ return -ENODEV;
+ }
+ hidinput = list_entry(hid->inputs.next, struct hid_input, list);
+ dev = hidinput->input;
+
if (!dev) {
hid_err(hid, "Struct input_dev not set!\n");
return -EINVAL;
