HID: hid-thrustmaster: fix OOB read in thrustmaster_interrupts

Syzbot reported an slab-out-of-bounds Read in thrustmaster_probe() bug.
The root case is in missing validation check of actual number of endpoints.

Code should not blindly access usb_host_interface::endpoint array, since
it may contain less endpoints than code expects.

Fix it by adding missing validaion check and print an error if
number of endpoints do not match expected number

Fixes: c49c33637802 ("HID: support for initialization of some Thrustmaster wheels")
Reported-and-tested-by: syzbot+35eebd505e97d315d01c@syzkaller.appspotmail.com
Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

diff --git a/drivers/hid/hid-thrustmaster.c b/drivers/hid/hid-thrustmaster.c
index a4e20f9..c3e6d69 100644 (file)
--- a/drivers/hid/hid-thrustmaster.c
+++ b/drivers/hid/hid-thrustmaster.c
@@ -160,6 +160,12 @@ static void thrustmaster_interrupts(struct hid_device *hdev)
                return;
        }
 
+       if (usbif->cur_altsetting->desc.bNumEndpoints < 2) {
+               kfree(send_buf);
+               hid_err(hdev, "Wrong number of endpoints?\n");
+               return;
+       }
+
        ep = &usbif->cur_altsetting->endpoint[1];
        b_ep = ep->desc.bEndpointAddress;