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authorAlan Stern <stern@rowland.harvard.edu>2019-10-03 14:53:59 -0400
committerBenjamin Tissoires <benjamin.tissoires@redhat.com>2019-10-03 15:36:40 -0400
commitd9d4b1e46d9543a82c23f6df03f4ad697dab361b (patch)
tree5a405a2f78b1029f4cc6d6ee743f0bec31319b42 /drivers/hid/hid-lg4ff.c
parentfe2199cfd1516e90e03c033c52c9a28da09d9986 (diff)
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>
Diffstat (limited to 'drivers/hid/hid-lg4ff.c')
-rw-r--r--drivers/hid/hid-lg4ff.c11
1 files changed, 9 insertions, 2 deletions
diff --git a/drivers/hid/hid-lg4ff.c b/drivers/hid/hid-lg4ff.c
index 03f0220062ca..5e6a0cef2a06 100644
--- a/drivers/hid/hid-lg4ff.c
+++ b/drivers/hid/hid-lg4ff.c
@@ -1253,8 +1253,8 @@ static int lg4ff_handle_multimode_wheel(struct hid_device *hid, u16 *real_produc
int lg4ff_init(struct hid_device *hid)
{
- 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;
struct list_head *report_list = &hid->report_enum[HID_OUTPUT_REPORT].report_list;
struct hid_report *report = list_entry(report_list->next, struct hid_report, list);
const struct usb_device_descriptor *udesc = &(hid_to_usb_dev(hid)->descriptor);
@@ -1266,6 +1266,13 @@ int lg4ff_init(struct hid_device *hid)
int mmode_ret, mmode_idx = -1;
u16 real_product_id;
+ 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;
+
/* Check that the report looks ok */
if (!hid_validate_values(hid, HID_OUTPUT_REPORT, 0, 0, 7))
return -1;