From 734ca9897e8cdb5ccd3fbdc6f84bb5304110f365 Mon Sep 17 00:00:00 2001
From: Xuan <xuan@live.com>
Date: Tue, 4 Feb 2020 05:03:21 +0000
Subject: [PATCH] Support descriptors with non-standard length.

---
 facedancer/USBConfiguration.py | 2 +-
 facedancer/USBDevice.py        | 2 +-
 facedancer/USBEndpoint.py      | 2 +-
 facedancer/USBInterface.py     | 2 +-
 4 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/facedancer/USBConfiguration.py b/facedancer/USBConfiguration.py
index aa5cb4f..3563c2b 100644
--- a/facedancer/USBConfiguration.py
+++ b/facedancer/USBConfiguration.py
@@ -52,7 +52,7 @@ def from_binary_descriptor(cls, data):
 
         # Unpack the main colleciton of data into the descriptor itself.
         descriptor_type, total_length, num_interfaces, index, string_index, \
-            attributes, max_power = struct.unpack('<xBHBBBBB', data[0:length])
+            attributes, max_power = struct.unpack_from('<xBHBBBBB', data[0:length])
 
         # Extract the subordinate descriptors, and parse them.
         interfaces = cls._parse_subordinate_descriptors(data[length:total_length])
diff --git a/facedancer/USBDevice.py b/facedancer/USBDevice.py
index 6b5c065..0330cc7 100644
--- a/facedancer/USBDevice.py
+++ b/facedancer/USBDevice.py
@@ -103,7 +103,7 @@ def from_binary_descriptor(cls, data):
         spec_version_msb, spec_version_lsb, device_class, device_subclass, device_protocol, \
                 max_packet_size_ep0, vendor_id, product_id, device_rev_msb, device_rev_lsb, \
                 manufacturer_string_index, product_string_index, \
-                serial_number_string_index, num_configurations = struct.unpack("<xxBBBBBBHHBBBBBB", data)
+                serial_number_string_index, num_configurations = struct.unpack_from("<xxBBBBBBHHBBBBBB", data)
 
         # FIXME: generate better placeholder configurations
         configurations  = [USBConfiguration()] * num_configurations
diff --git a/facedancer/USBEndpoint.py b/facedancer/USBEndpoint.py
index e2ef884..7a88d0d 100644
--- a/facedancer/USBEndpoint.py
+++ b/facedancer/USBEndpoint.py
@@ -52,7 +52,7 @@ def from_binary_descriptor(cls, data):
         """
 
         # Parse the core descriptor into its components...
-        address, attributes, max_packet_size, interval = struct.unpack("xxBBHB", data)
+        address, attributes, max_packet_size, interval = struct.unpack_from("xxBBHB", data)
 
         # ... and break down the packed fields.
         number        = address & 0x7F
diff --git a/facedancer/USBInterface.py b/facedancer/USBInterface.py
index ba08e36..7378a87 100644
--- a/facedancer/USBInterface.py
+++ b/facedancer/USBInterface.py
@@ -79,7 +79,7 @@ def from_binary_descriptor(cls, data):
         """
         interface_number, alternate_setting, num_endpoints, interface_class, \
                 interface_subclass, interface_protocol, interface_string_index \
-                = struct.unpack("xxBBBBBBB", data)
+                = struct.unpack_from("xxBBBBBBB", data)
         return cls(interface_number, alternate_setting, interface_class,
                    interface_subclass, interface_protocol, interface_string_index)