test/test_refaddr_bitness.py

   1 #------------------------------------------------------------------------------
   2 # elftools tests
   3 #
   4 # Seva Alekseyev (sevaa@sprynet.com)
   5 # This code is in the public domain
   6 #
   7 # The error that motivated this fix was in an iOS binary in Mach-O format. It
   8 # had v2 DWARF data, but it was targeting a 64 bit architecture. Before the fix,
   9 # pyelftools would assume that DW_FORM_ref_addr attribute took 4 bytes and
  10 # misparse the DWARF data in the binary.
  11 #
  12 # Since pyelftools doesn't work with Mach-O files, I've taken a sample binary
  13 # apart, and saved the three relevant sections - info, abbrev, and str as flat
  14 # files. The metadata (the fact that it's targeting ARM64) is hard-coded, since
  15 # the Mach-O header isn't preserved.
  16 #------------------------------------------------------------------------------
  17
  18 import unittest
  19 import os, sys, io
  20
  21 from elftools.dwarf.dwarfinfo import DWARFInfo, DebugSectionDescriptor, DwarfConfig
  22
  23 class TestRefAddrOnDWARFv2With64BitTarget(unittest.TestCase):
  24     def test_main(self):
  25         # Read the three saved sections as bytestreams
  26         with open(os.path.join('test', 'testfiles_for_unittests', 'arm64_on_dwarfv2.info.dat'), 'rb') as f:
  27             info = f.read()
  28         with open(os.path.join('test', 'testfiles_for_unittests', 'arm64_on_dwarfv2.abbrev.dat'), 'rb') as f:
  29             abbrev = f.read()
  30         with open(os.path.join('test', 'testfiles_for_unittests', 'arm64_on_dwarfv2.str.dat'), 'rb') as f:
  31             str = f.read()
  32
  33         # Parse the DWARF info
  34         di = DWARFInfo(
  35             config = DwarfConfig(little_endian = True, default_address_size = 8, machine_arch = "ARM64"),
  36             debug_info_sec = DebugSectionDescriptor(io.BytesIO(info), '__debug_info', None, len(info), 0),
  37             debug_aranges_sec = None,
  38             debug_abbrev_sec = DebugSectionDescriptor(io.BytesIO(abbrev), '__debug_abbrev', None, len(abbrev), 0),
  39             debug_frame_sec = None,
  40             eh_frame_sec = None,
  41             debug_str_sec = DebugSectionDescriptor(io.BytesIO(str), '__debug_str', None, len(str), 0),
  42             debug_loc_sec = None,
  43             debug_ranges_sec = None,
  44             debug_line_sec = None,
  45             debug_pubtypes_sec = None,
  46             debug_pubnames_sec = None,
  47             debug_addr_sec=None,
  48             debug_str_offsets_sec=None,
  49         )
  50
  51         CUs = [cu for cu in di.iter_CUs()]
  52         # Locate a CU that I know has a reference in DW_FORM_ref_addr form
  53         CU = CUs[21]
  54         self.assertEqual(CU['version'], 2)
  55         # Make sure pyelftools appreciates the difference between the target address size and DWARF inter-DIE offset size
  56         self.assertEqual(CU.structs.dwarf_format, 32)
  57         self.assertEqual(CU['address_size'], 8)
  58         DIEs = [die for die in CU.iter_DIEs()]
  59         # Before the patch, DIE #2 is misparsed, the current offset is off, the rest are misparsed too
  60         self.assertEqual(len(DIEs), 15)
  61         # It was 9 before the patch, which was wrong.
  62
  63 if __name__ == '__main__':
  64     unittest.main()