Re: [syzbot] [usb?] UBSAN: array-index-out-of-bounds in usbhid_parse

[Nikita Zhandarovich]

#syz test https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
---
 drivers/hid/usbhid/hid-core.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/hid/usbhid/hid-core.c b/drivers/hid/usbhid/hid-core.c
index a90ed2ceae84..f38a4bd3a20e 100644
--- a/drivers/hid/usbhid/hid-core.c
+++ b/drivers/hid/usbhid/hid-core.c
@@ -1020,6 +1020,9 @@ static int usbhid_parse(struct hid_device *hid)
 	num_descriptors = min_t(int, hdesc->bNumDescriptors,
 	       (hdesc->bLength - offset) / sizeof(struct hid_class_descriptor));
 
+	if (num_descriptors > ARRAY_SIZE(hdesc->desc))
+		num_descriptors = ARRAY_SIZE(hdesc->desc);
+
 	for (n = 0; n < num_descriptors; n++)
 		if (hdesc->desc[n].bDescriptorType == HID_DT_REPORT)
 			rsize = le16_to_cpu(hdesc->desc[n].wDescriptorLength);