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#-------------------------------------------------------------------------------
# elftools tests
#
# Eli Bendersky (eliben@gmail.com)
# This code is in the public domain
#-------------------------------------------------------------------------------
import unittest
from io import BytesIO
from elftools.dwarf.callframe import (
CallFrameInfo, CIE, FDE, instruction_name, CallFrameInstruction,
RegisterRule, DecodedCallFrameTable, CFARule)
from elftools.dwarf.structs import DWARFStructs
from elftools.dwarf.descriptions import (describe_CFI_instructions,
set_global_machine_arch)
from elftools.dwarf.enums import DW_EH_encoding_flags
from elftools.elf.elffile import ELFFile
from os.path import join
class TestCallFrame(unittest.TestCase):
def assertInstruction(self, instr, name, args):
self.assertIsInstance(instr, CallFrameInstruction)
self.assertEqual(instruction_name(instr.opcode), name)
self.assertEqual(instr.args, args)
def test_spec_sample_d6(self):
# D.6 sample in DWARFv3
s = BytesIO()
data = (b'' +
# first comes the CIE
b'\x20\x00\x00\x00' + # length
b'\xff\xff\xff\xff' + # CIE_id
b'\x03\x00\x04\x7c' + # version, augmentation, caf, daf
b'\x08' + # return address
b'\x0c\x07\x00' +
b'\x08\x00' +
b'\x07\x01' +
b'\x07\x02' +
b'\x07\x03' +
b'\x08\x04' +
b'\x08\x05' +
b'\x08\x06' +
b'\x08\x07' +
b'\x09\x08\x01' +
b'\x00' +
# then comes the FDE
b'\x28\x00\x00\x00' + # length
b'\x00\x00\x00\x00' + # CIE_pointer (to CIE at 0)
b'\x44\x33\x22\x11' + # initial_location
b'\x54\x00\x00\x00' + # address range
b'\x41' +
b'\x0e\x0c' + b'\x41' +
b'\x88\x01' + b'\x41' +
b'\x86\x02' + b'\x41' +
b'\x0d\x06' + b'\x41' +
b'\x84\x03' + b'\x4b' +
b'\xc4' + b'\x41' +
b'\xc6' +
b'\x0d\x07' + b'\x41' +
b'\xc8' + b'\x41' +
b'\x0e\x00' +
b'\x00\x00'
)
s.write(data)
structs = DWARFStructs(little_endian=True, dwarf_format=32, address_size=4)
cfi = CallFrameInfo(s, len(data), 0, structs)
entries = cfi.get_entries()
self.assertEqual(len(entries), 2)
self.assertIsInstance(entries[0], CIE)
self.assertEqual(entries[0]['length'], 32)
self.assertEqual(entries[0]['data_alignment_factor'], -4)
self.assertEqual(entries[0]['return_address_register'], 8)
self.assertEqual(len(entries[0].instructions), 11)
self.assertInstruction(entries[0].instructions[0],
'DW_CFA_def_cfa', [7, 0])
self.assertInstruction(entries[0].instructions[8],
'DW_CFA_same_value', [7])
self.assertInstruction(entries[0].instructions[9],
'DW_CFA_register', [8, 1])
self.assertTrue(isinstance(entries[1], FDE))
self.assertEqual(entries[1]['length'], 40)
self.assertEqual(entries[1]['CIE_pointer'], 0)
self.assertEqual(entries[1]['address_range'], 84)
self.assertIsNone(entries[1].lsda_pointer)
self.assertIs(entries[1].cie, entries[0])
self.assertEqual(len(entries[1].instructions), 21)
self.assertInstruction(entries[1].instructions[0],
'DW_CFA_advance_loc', [1])
self.assertInstruction(entries[1].instructions[1],
'DW_CFA_def_cfa_offset', [12])
self.assertInstruction(entries[1].instructions[9],
'DW_CFA_offset', [4, 3])
self.assertInstruction(entries[1].instructions[18],
'DW_CFA_def_cfa_offset', [0])
self.assertInstruction(entries[1].instructions[20],
'DW_CFA_nop', [])
# Now let's decode it...
decoded_CIE = entries[0].get_decoded()
self.assertEqual(decoded_CIE.reg_order, list(range(9)))
self.assertEqual(len(decoded_CIE.table), 1)
self.assertEqual(decoded_CIE.table[0]['cfa'].reg, 7)
self.assertEqual(decoded_CIE.table[0]['pc'], 0)
self.assertEqual(decoded_CIE.table[0]['cfa'].offset, 0)
self.assertEqual(decoded_CIE.table[0][4].type, RegisterRule.SAME_VALUE)
self.assertEqual(decoded_CIE.table[0][8].type, RegisterRule.REGISTER)
self.assertEqual(decoded_CIE.table[0][8].arg, 1)
decoded_FDE = entries[1].get_decoded()
self.assertEqual(decoded_FDE.reg_order, list(range(9)))
self.assertEqual(decoded_FDE.table[0]['cfa'].reg, 7)
self.assertEqual(decoded_FDE.table[0]['cfa'].offset, 0)
self.assertEqual(decoded_FDE.table[0]['pc'], 0x11223344)
self.assertEqual(decoded_FDE.table[0][8].type, RegisterRule.REGISTER)
self.assertEqual(decoded_FDE.table[0][8].arg, 1)
self.assertEqual(decoded_FDE.table[1]['cfa'].reg, 7)
self.assertEqual(decoded_FDE.table[1]['cfa'].offset, 12)
self.assertEqual(decoded_FDE.table[2][8].type, RegisterRule.OFFSET)
self.assertEqual(decoded_FDE.table[2][8].arg, -4)
self.assertEqual(decoded_FDE.table[2][4].type, RegisterRule.SAME_VALUE)
self.assertEqual(decoded_FDE.table[5]['pc'], 0x11223344 + 20)
self.assertEqual(decoded_FDE.table[5][4].type, RegisterRule.OFFSET)
self.assertEqual(decoded_FDE.table[5][4].arg, -12)
self.assertEqual(decoded_FDE.table[6]['pc'], 0x11223344 + 64)
self.assertEqual(decoded_FDE.table[9]['pc'], 0x11223344 + 76)
def test_describe_CFI_instructions(self):
# The data here represents a single CIE
data = (b'' +
b'\x16\x00\x00\x00' + # length
b'\xff\xff\xff\xff' + # CIE_id
b'\x03\x00\x04\x7c' + # version, augmentation, caf, daf
b'\x08' + # return address
b'\x0c\x07\x02' +
b'\x10\x02\x07\x03\x01\x02\x00\x00\x06\x06')
s = BytesIO(data)
structs = DWARFStructs(little_endian=True, dwarf_format=32, address_size=4)
cfi = CallFrameInfo(s, len(data), 0, structs)
entries = cfi.get_entries()
set_global_machine_arch('x86')
self.assertEqual(describe_CFI_instructions(entries[0]),
( ' DW_CFA_def_cfa: r7 (edi) ofs 2\n' +
' DW_CFA_expression: r2 (edx) (DW_OP_addr: 201; DW_OP_deref; DW_OP_deref)\n'))
def test_CFIEntry_get_decoded(self):
oracle_decoded = DecodedCallFrameTable(
table = [
{'pc': 0, 'cfa': CFARule(reg = 29, offset = 0, expr = None)}
],
reg_order = []
)
test_dir = join('test', 'testfiles_for_unittests')
with open(join(test_dir, 'simple_mipsel.elf'), 'rb') as f:
elf = ELFFile(f)
di = elf.get_dwarf_info()
entries = di.CFI_entries()
decoded = entries[0].get_decoded()
self.assertEqual(oracle_decoded.table[0]['cfa'].reg,
decoded.table[0]['cfa'].reg
)
self.assertEqual(oracle_decoded.table[0]['cfa'].offset,
decoded.table[0]['cfa'].offset)
def test_ehframe_fde_with_lsda_pointer(self):
# CIE and FDE dumped from exceptions_0, offset 0xcc0
# binary is at https://github.com/angr/binaries/blob/master/tests/x86_64/exceptions_0
data = (b'' +
# CIE
b'\x1c\x00\x00\x00' + # length
b'\x00\x00\x00\x00' + # ID
b'\x01' + # version
b'\x7a\x50\x4c\x52\x00' + # augmentation string
b'\x01' + # code alignment
b'\x78' + # data alignment
b'\x10' + # return address register
b'\x07' + # augmentation data length
b'\x9b' + # personality function pointer encoding
b'\x3d\x13\x20\x00' + # personality function pointer
b'\x1b' + # LSDA pointer encoding
b'\x1b' + # FDE encoding
b'\x0c\x07\x08\x90' + # initial instructions
b'\x01\x00\x00' +
# FDE
b'\x24\x00\x00\x00' + # length
b'\x24\x00\x00\x00' + # CIE reference pointer
b'\x62\xfd\xff\xff' + # pc begin
b'\x89\x00\x00\x00' + # pc range
b'\x04' + # augmentation data length
b'\xb7\x00\x00\x00' + # LSDA pointer
b'\x41\x0e\x10\x86' + # initial instructions
b'\x02\x43\x0d\x06' +
b'\x45\x83\x03\x02' +
b'\x7f\x0c\x07\x08' +
b'\x00\x00\x00'
)
s = BytesIO(data)
structs = DWARFStructs(little_endian=True, dwarf_format=32, address_size=8)
cfi = CallFrameInfo(s, len(data), 0, structs, for_eh_frame=True)
entries = cfi.get_entries()
self.assertEqual(len(entries), 2)
self.assertIsInstance(entries[0], CIE)
self.assertIn('LSDA_encoding', entries[0].augmentation_dict)
# check LSDA encoding
lsda_encoding = entries[0].augmentation_dict['LSDA_encoding']
basic_encoding = lsda_encoding & 0x0f
modifier = lsda_encoding & 0xf0
self.assertEqual(basic_encoding, DW_EH_encoding_flags['DW_EH_PE_sdata4'])
self.assertEqual(modifier, DW_EH_encoding_flags['DW_EH_PE_pcrel'])
self.assertIsInstance(entries[1], FDE)
self.assertEqual(entries[1].lsda_pointer, 232)
if __name__ == '__main__':
unittest.main()
|
