AttributeError when loading a UEFI image

[zolutal]

Description

when loading a UEFI image, an error will occur trying to set the backend's arch attribute.

In [1]: import cle

In [2]: cle.Loader("./FV_RECOVERY.fd")
---------------------------------------------------------------------------
AttributeError                            Traceback (most recent call last)
Cell In [2], line 1
----> 1 cle.Loader("./FV_RECOVERY.fd")

File ~/.virtualenvs/angr/lib/python3.10/site-packages/cle/loader.py:188, in Loader.__init__(self, main_binary, auto_load_libs, concrete_target, force_load_libs, skip_libs, main_opts, lib_opts, ld_path, use_system_libs, ignore_import_version_numbers, case_insensitive, rebase_granularity, except_missing_libs, aslr, perform_relocations, load_debug_info, page_size, preload_libs, arch)
    186     self._main_opts.update({"arch": arch})
    187 self.preload_libs = []
--> 188 self.initial_load_objects = self._internal_load(
    189     main_binary, *preload_libs, *force_load_libs, preloading=(main_binary, *preload_libs)
    190 )
    192 # cache
    193 self._last_object = None

File ~/.virtualenvs/angr/lib/python3.10/site-packages/cle/loader.py:782, in Loader._internal_load(self, preloading, *args)
    780     log.info("Skipping load request %s - already loaded", main_spec)
    781     continue
--> 782 obj = self._load_object_isolated(main_spec)
    783 objects.append(obj)
    784 objects.extend(obj.child_objects)

File ~/.virtualenvs/angr/lib/python3.10/site-packages/cle/loader.py:986, in Loader._load_object_isolated(self, spec)
    983 # STEP 4: LOAD!
    984 log.debug("... loading with %s", backend_cls)
--> 986 result = backend_cls(binary, binary_stream, is_main_bin=self._main_object is None, loader=self, **options)
    987 result.close()
    988 return result

File ~/.virtualenvs/angr/lib/python3.10/site-packages/cle/backends/uefi_firmware.py:97, in UefiFirmware.__init__(self, *args, **kwargs)
     94         self.child_objects.append(child)
     96 if self.child_objects:
---> 97     self.arch = self.child_objects[0].arch
     98 else:
     99     log.warning("Loaded empty UEFI firmware?")

AttributeError: can't set attribute 'arch'

Steps to reproduce the bug

with: pip install uefi-firmware==1.9

import cle
cle.Loader("./FV_RECOVERY.fd")

FV_RECOVERY.tar.gz

Environment

/home/jmill/.virtualenvs/angr/lib/python3.10/site-packages/angr/misc/bug_report.py:1: DeprecationWarning: the imp module is deprecated in favour of importlib and slated for removal in Python 3.12; see the module's documentation for alternative uses
  import imp
angr environment report
=============================
Date: 2023-08-15 17:46:16.938857
Running in virtual environment at /home/jmill/.virtualenvs/angr
Platform: linux-x86_64
Python version: 3.10.12 (main, Jun 11 2023, 05:26:28) [GCC 11.4.0]
######## angr #########
Python found it in /home/jmill/.virtualenvs/angr/lib/python3.10/site-packages/angr
Pip version angr 9.2.64
Couldn't find git info
######## ailment #########
Python found it in /home/jmill/.virtualenvs/angr/lib/python3.10/site-packages/ailment
Pip version ailment 9.2.64
Couldn't find git info
######## cle #########
Python found it in /home/jmill/.virtualenvs/angr/lib/python3.10/site-packages/cle
Pip version cle 9.2.64
Couldn't find git info
######## pyvex #########
Python found it in /home/jmill/.virtualenvs/angr/lib/python3.10/site-packages/pyvex
Pip version pyvex 9.2.64
Couldn't find git info
######## claripy #########
Python found it in /home/jmill/.virtualenvs/angr/lib/python3.10/site-packages/claripy
Pip version claripy 9.2.64
Couldn't find git info
######## archinfo #########
Python found it in /home/jmill/.virtualenvs/angr/lib/python3.10/site-packages/archinfo
Pip version archinfo 9.2.64
Couldn't find git info
######## z3 #########
Python found it in /home/jmill/.virtualenvs/angr/lib/python3.10/site-packages/z3
Pip version z3-solver 4.10.2.0
Couldn't find git info
######## unicorn #########
Python found it in /home/jmill/.virtualenvs/angr/lib/python3.10/site-packages/unicorn
Pip version unicorn 2.0.1.post1
Couldn't find git info
######### Native Module Info ##########
angr: <CDLL '/home/jmill/.virtualenvs/angr/lib/python3.10/site-packages/angr/state_plugins/../lib/angr_native.so', handle 55c12e4eda10 at 0x7f8b22438af0>
unicorn: <CDLL '/home/jmill/.virtualenvs/angr/lib/python3.10/site-packages/unicorn/lib/libunicorn.so.2', handle 55c12df79160 at 0x7f8b25081d80>
pyvex: <cffi.api._make_ffi_library.<locals>.FFILibrary object at 0x7f8b25da7a00>
z3: <CDLL '/home/jmill/.virtualenvs/angr/lib/python3.10/site-packages/z3/lib/libz3.so', handle 55c12dd13420 at 0x7f8b27cff970>

Additional context

breaking commit: 0833a23
using self.arch = ... is no longer valid for backends, self._arch = ... or self.set_arch(...) should be used instead