Allow reading HID descriptors larger than 255 bytes

Fixes #114
hughsie · Nov 22, 2023 · de7d8ee · de7d8ee
1 parent 860108f
commit de7d8ee
Showing 1 changed file with 4 additions and 2 deletions.
diff --git a/gusb/gusb-device.c b/gusb/gusb-device.c
@@ -1343,6 +1343,7 @@ g_usb_device_get_hid_descriptor_for_interface(GUsbDevice *self, GUsbInterface *i
 	const guint8 *buf;
 	gsize actual_length = 0;
 	gsize buf2sz;
+	guint16 buf2szle = 0;
 	g_autofree guint8 *buf2 = NULL;
 
 	extra = g_usb_interface_get_extra(intf);
@@ -1373,15 +1374,16 @@ g_usb_device_get_hid_descriptor_for_interface(GUsbDevice *self, GUsbInterface *i
 			    (guint)LIBUSB_DT_HID);
 		return NULL;
 	}
-	if (buf[7] == 0) {
+	memcpy(&buf2szle, buf + 7, sizeof(buf2szle));
+	buf2sz = GUINT16_FROM_LE(buf2szle);
+	if (buf2sz == 0) {
 		g_set_error(error,
 			    G_IO_ERROR,
 			    G_IO_ERROR_NOT_FOUND,
 			    "missing data on HID interface 0x%x",
 			    g_usb_interface_get_number(intf));
 		return NULL;
 	}
-	buf2sz = buf[7];
 	g_debug("get 0x%x bytes of HID descriptor", (guint)buf2sz);
 
 	/* get HID descriptor */