def _locate_parameter(library, disas, start_idx, target_register, mem_tag):
retval = None
idx = start_idx
while idx > 0:
idx -= 1
earlier_insn = disas[idx]
_, written = earlier_insn.regs_access()
if target_register not in written:
continue
elif earlier_insn.id != capstone.x86_const.X86_INS_LEA:
break
# Here we know it was a <lea ..., %rsi>, and these
# accesses will mostly be RIP-relative on x86_64 so we only support
# <lea xxx(%rip), %rsi> for now.
_, val = list(earlier_insn.operands)
if val.type == mem_tag and val.value.mem.base == capstone.x86.X86_REG_RIP:
straddr = earlier_insn.address + val.value.mem.disp + earlier_insn.size
elffile = ELFFile(library.fd)
stroff = next(elffile.address_offsets(straddr))
strval = parse_cstring_from_stream(library.fd, stroff)
retval = strval.decode('utf-8')
break
return retval
def __getitem__(self, offset):
return parse_cstring_from_stream(self.stream, self.offset + offset)
def test_large2(self):
text = self._make_random_bytes(5000) + b'\x00' + b'jujajaja'
sio = BytesIO(text)
self.assertEqual(parse_cstring_from_stream(sio), text[:5000])
self.assertEqual(parse_cstring_from_stream(sio, 2348), text[2348:5000])
def test_large1(self):
text = b'i' * 400 + b'\x00' + b'bb'
sio = BytesIO(text)
self.assertEqual(parse_cstring_from_stream(sio), b'i' * 400)
self.assertEqual(parse_cstring_from_stream(sio, 150), b'i' * 250)
def test_small2(self):
sio = BytesIO(b'12345\x006789\x00abcdefg\x00iii')
self.assertEqual(parse_cstring_from_stream(sio), b'12345')
self.assertEqual(parse_cstring_from_stream(sio, 5), b'')
self.assertEqual(parse_cstring_from_stream(sio, 6), b'6789')
def test_small1(self):
sio = BytesIO(b'abcdefgh\x0012345')
self.assertEqual(parse_cstring_from_stream(sio), b'abcdefgh')
self.assertEqual(parse_cstring_from_stream(sio, 2), b'cdefgh')
self.assertEqual(parse_cstring_from_stream(sio, 8), b'')
def test_large2(self):
text = self._make_random_bytes(5000) + b'\x00' + b'jujajaja'
sio = BytesIO(text)
self.assertEqual(parse_cstring_from_stream(sio), text[:5000])
self.assertEqual(parse_cstring_from_stream(sio, 2348), text[2348:5000])
def test_large1(self):
text = b'i' * 400 + b'\x00' + b'bb'
sio = BytesIO(text)
self.assertEqual(parse_cstring_from_stream(sio), b'i' * 400)
self.assertEqual(parse_cstring_from_stream(sio, 150), b'i' * 250)
def test_small2(self):
sio = BytesIO(b'12345\x006789\x00abcdefg\x00iii')
self.assertEqual(parse_cstring_from_stream(sio), b'12345')
self.assertEqual(parse_cstring_from_stream(sio, 5), b'')
self.assertEqual(parse_cstring_from_stream(sio, 6), b'6789')
def test_small1(self):
sio = BytesIO(b'abcdefgh\x0012345')
self.assertEqual(parse_cstring_from_stream(sio), b'abcdefgh')
self.assertEqual(parse_cstring_from_stream(sio, 2), b'cdefgh')
self.assertEqual(parse_cstring_from_stream(sio, 8), b'')