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: syzbot+403741a091bf41d4ae79@syzkaller.appspotmail.com
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
CC: <stable@vger.kernel.org>
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
diff --git a/drivers/hid/hid-tmff.c b/drivers/hid/hid-tmff.c
index bdfc5ff..90acef3 100644
--- a/drivers/hid/hid-tmff.c
+++ b/drivers/hid/hid-tmff.c
@@ -124,12 +124,18 @@ static int tmff_init(struct hid_device *hid, const signed short *ff_bits)
struct tmff_device *tmff;
struct hid_report *report;
struct list_head *report_list;
- struct hid_input *hidinput = list_entry(hid->inputs.next,
- struct hid_input, list);
- struct input_dev *input_dev = hidinput->input;
+ struct hid_input *hidinput;
+ struct input_dev *input_dev;
int error;
int i;
+ if (list_empty(&hid->inputs)) {
+ hid_err(hid, "no inputs found\n");
+ return -ENODEV;
+ }
+ hidinput = list_entry(hid->inputs.next, struct hid_input, list);
+ input_dev = hidinput->input;
+
tmff = kzalloc(sizeof(struct tmff_device), GFP_KERNEL);
if (!tmff)
return -ENOMEM;