cpython/Lib/test/test_binascii.py
Youfu Zhang fe47d9bee3
gh-118314: Fix padding edge case in binascii.a2b_base64 strict mode (GH-118320)
Fix an edge case in `binascii.a2b_base64` strict mode, where
excessive padding was not detected when no padding is necessary.

Co-authored-by: Terry Jan Reedy <tjreedy@udel.edu>
Co-authored-by: Pieter Eendebak <pieter.eendebak@gmail.com>
2024-05-07 11:18:45 +02:00

522 lines
22 KiB
Python

"""Test the binascii C module."""
import unittest
import binascii
import array
import re
from test.support import bigmemtest, _1G, _4G
from test.support.hypothesis_helper import hypothesis
# Note: "*_hex" functions are aliases for "(un)hexlify"
b2a_functions = ['b2a_base64', 'b2a_hex', 'b2a_qp', 'b2a_uu',
'hexlify']
a2b_functions = ['a2b_base64', 'a2b_hex', 'a2b_qp', 'a2b_uu',
'unhexlify']
all_functions = a2b_functions + b2a_functions + ['crc32', 'crc_hqx']
class BinASCIITest(unittest.TestCase):
type2test = bytes
# Create binary test data
rawdata = b"The quick brown fox jumps over the lazy dog.\r\n"
# Be slow so we don't depend on other modules
rawdata += bytes(range(256))
rawdata += b"\r\nHello world.\n"
def setUp(self):
self.data = self.type2test(self.rawdata)
def assertConversion(self, original, converted, restored, **kwargs):
self.assertIsInstance(original, bytes)
self.assertIsInstance(converted, bytes)
self.assertIsInstance(restored, bytes)
if converted:
self.assertLess(max(converted), 128)
self.assertEqual(original, restored, msg=f'{self.type2test=} {kwargs=}')
def test_exceptions(self):
# Check module exceptions
self.assertTrue(issubclass(binascii.Error, Exception))
self.assertTrue(issubclass(binascii.Incomplete, Exception))
def test_functions(self):
# Check presence of all functions
for name in all_functions:
self.assertTrue(hasattr(getattr(binascii, name), '__call__'))
self.assertRaises(TypeError, getattr(binascii, name))
def test_returned_value(self):
# Limit to the minimum of all limits (b2a_uu)
MAX_ALL = 45
raw = self.rawdata[:MAX_ALL]
for fa, fb in zip(a2b_functions, b2a_functions):
a2b = getattr(binascii, fa)
b2a = getattr(binascii, fb)
try:
a = b2a(self.type2test(raw))
res = a2b(self.type2test(a))
except Exception as err:
self.fail("{}/{} conversion raises {!r}".format(fb, fa, err))
self.assertEqual(res, raw, "{}/{} conversion: "
"{!r} != {!r}".format(fb, fa, res, raw))
self.assertConversion(raw, a, res)
self.assertIsInstance(binascii.crc_hqx(raw, 0), int)
self.assertIsInstance(binascii.crc32(raw), int)
def test_base64valid(self):
# Test base64 with valid data
MAX_BASE64 = 57
lines = []
for i in range(0, len(self.rawdata), MAX_BASE64):
b = self.type2test(self.rawdata[i:i+MAX_BASE64])
a = binascii.b2a_base64(b)
lines.append(a)
res = bytes()
for line in lines:
a = self.type2test(line)
b = binascii.a2b_base64(a)
res += b
self.assertEqual(res, self.rawdata)
def test_base64invalid(self):
# Test base64 with random invalid characters sprinkled throughout
# (This requires a new version of binascii.)
MAX_BASE64 = 57
lines = []
for i in range(0, len(self.data), MAX_BASE64):
b = self.type2test(self.rawdata[i:i+MAX_BASE64])
a = binascii.b2a_base64(b)
lines.append(a)
fillers = bytearray()
valid = b"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789+/"
for i in range(256):
if i not in valid:
fillers.append(i)
def addnoise(line):
noise = fillers
ratio = len(line) // len(noise)
res = bytearray()
while line and noise:
if len(line) // len(noise) > ratio:
c, line = line[0], line[1:]
else:
c, noise = noise[0], noise[1:]
res.append(c)
return res + noise + line
res = bytearray()
for line in map(addnoise, lines):
a = self.type2test(line)
b = binascii.a2b_base64(a)
res += b
self.assertEqual(res, self.rawdata)
# Test base64 with just invalid characters, which should return
# empty strings. TBD: shouldn't it raise an exception instead ?
self.assertEqual(binascii.a2b_base64(self.type2test(fillers)), b'')
def test_base64_strict_mode(self):
# Test base64 with strict mode on
def _assertRegexTemplate(assert_regex: str, data: bytes, non_strict_mode_expected_result: bytes):
with self.assertRaisesRegex(binascii.Error, assert_regex):
binascii.a2b_base64(self.type2test(data), strict_mode=True)
self.assertEqual(binascii.a2b_base64(self.type2test(data), strict_mode=False),
non_strict_mode_expected_result)
self.assertEqual(binascii.a2b_base64(self.type2test(data)),
non_strict_mode_expected_result)
def assertExcessData(data, non_strict_mode_expected_result: bytes):
_assertRegexTemplate(r'(?i)Excess data', data, non_strict_mode_expected_result)
def assertNonBase64Data(data, non_strict_mode_expected_result: bytes):
_assertRegexTemplate(r'(?i)Only base64 data', data, non_strict_mode_expected_result)
def assertLeadingPadding(data, non_strict_mode_expected_result: bytes):
_assertRegexTemplate(r'(?i)Leading padding', data, non_strict_mode_expected_result)
def assertDiscontinuousPadding(data, non_strict_mode_expected_result: bytes):
_assertRegexTemplate(r'(?i)Discontinuous padding', data, non_strict_mode_expected_result)
def assertExcessPadding(data, non_strict_mode_expected_result: bytes):
_assertRegexTemplate(r'(?i)Excess padding', data, non_strict_mode_expected_result)
# Test excess data exceptions
assertExcessData(b'ab==a', b'i')
assertExcessData(b'ab===', b'i')
assertExcessData(b'ab====', b'i')
assertExcessData(b'ab==:', b'i')
assertExcessData(b'abc=a', b'i\xb7')
assertExcessData(b'abc=:', b'i\xb7')
assertExcessData(b'ab==\n', b'i')
assertExcessData(b'abc==', b'i\xb7')
assertExcessData(b'abc===', b'i\xb7')
assertExcessData(b'abc====', b'i\xb7')
assertExcessData(b'abc=====', b'i\xb7')
# Test non-base64 data exceptions
assertNonBase64Data(b'\nab==', b'i')
assertNonBase64Data(b'ab:(){:|:&};:==', b'i')
assertNonBase64Data(b'a\nb==', b'i')
assertNonBase64Data(b'a\x00b==', b'i')
# Test malformed padding
assertLeadingPadding(b'=', b'')
assertLeadingPadding(b'==', b'')
assertLeadingPadding(b'===', b'')
assertLeadingPadding(b'====', b'')
assertLeadingPadding(b'=====', b'')
assertDiscontinuousPadding(b'ab=c=', b'i\xb7')
assertDiscontinuousPadding(b'ab=ab==', b'i\xb6\x9b')
assertExcessPadding(b'abcd=', b'i\xb7\x1d')
assertExcessPadding(b'abcd==', b'i\xb7\x1d')
assertExcessPadding(b'abcd===', b'i\xb7\x1d')
assertExcessPadding(b'abcd====', b'i\xb7\x1d')
assertExcessPadding(b'abcd=====', b'i\xb7\x1d')
def test_base64errors(self):
# Test base64 with invalid padding
def assertIncorrectPadding(data):
with self.assertRaisesRegex(binascii.Error, r'(?i)Incorrect padding'):
binascii.a2b_base64(self.type2test(data))
assertIncorrectPadding(b'ab')
assertIncorrectPadding(b'ab=')
assertIncorrectPadding(b'abc')
assertIncorrectPadding(b'abcdef')
assertIncorrectPadding(b'abcdef=')
assertIncorrectPadding(b'abcdefg')
assertIncorrectPadding(b'a=b=')
assertIncorrectPadding(b'a\nb=')
# Test base64 with invalid number of valid characters (1 mod 4)
def assertInvalidLength(data):
n_data_chars = len(re.sub(br'[^A-Za-z0-9/+]', br'', data))
expected_errmsg_re = \
r'(?i)Invalid.+number of data characters.+' + str(n_data_chars)
with self.assertRaisesRegex(binascii.Error, expected_errmsg_re):
binascii.a2b_base64(self.type2test(data))
assertInvalidLength(b'a')
assertInvalidLength(b'a=')
assertInvalidLength(b'a==')
assertInvalidLength(b'a===')
assertInvalidLength(b'a' * 5)
assertInvalidLength(b'a' * (4 * 87 + 1))
assertInvalidLength(b'A\tB\nC ??DE') # only 5 valid characters
def test_uu(self):
MAX_UU = 45
for backtick in (True, False):
lines = []
for i in range(0, len(self.data), MAX_UU):
b = self.type2test(self.rawdata[i:i+MAX_UU])
a = binascii.b2a_uu(b, backtick=backtick)
lines.append(a)
res = bytes()
for line in lines:
a = self.type2test(line)
b = binascii.a2b_uu(a)
res += b
self.assertEqual(res, self.rawdata)
self.assertEqual(binascii.a2b_uu(b"\x7f"), b"\x00"*31)
self.assertEqual(binascii.a2b_uu(b"\x80"), b"\x00"*32)
self.assertEqual(binascii.a2b_uu(b"\xff"), b"\x00"*31)
self.assertRaises(binascii.Error, binascii.a2b_uu, b"\xff\x00")
self.assertRaises(binascii.Error, binascii.a2b_uu, b"!!!!")
self.assertRaises(binascii.Error, binascii.b2a_uu, 46*b"!")
# Issue #7701 (crash on a pydebug build)
self.assertEqual(binascii.b2a_uu(b'x'), b'!> \n')
self.assertEqual(binascii.b2a_uu(b''), b' \n')
self.assertEqual(binascii.b2a_uu(b'', backtick=True), b'`\n')
self.assertEqual(binascii.a2b_uu(b' \n'), b'')
self.assertEqual(binascii.a2b_uu(b'`\n'), b'')
self.assertEqual(binascii.b2a_uu(b'\x00Cat'), b'$ $-A= \n')
self.assertEqual(binascii.b2a_uu(b'\x00Cat', backtick=True),
b'$`$-A=```\n')
self.assertEqual(binascii.a2b_uu(b'$`$-A=```\n'),
binascii.a2b_uu(b'$ $-A= \n'))
with self.assertRaises(TypeError):
binascii.b2a_uu(b"", True)
@hypothesis.given(
binary=hypothesis.strategies.binary(max_size=45),
backtick=hypothesis.strategies.booleans(),
)
def test_b2a_roundtrip(self, binary, backtick):
converted = binascii.b2a_uu(self.type2test(binary), backtick=backtick)
restored = binascii.a2b_uu(self.type2test(converted))
self.assertConversion(binary, converted, restored, backtick=backtick)
def test_crc_hqx(self):
crc = binascii.crc_hqx(self.type2test(b"Test the CRC-32 of"), 0)
crc = binascii.crc_hqx(self.type2test(b" this string."), crc)
self.assertEqual(crc, 14290)
self.assertRaises(TypeError, binascii.crc_hqx)
self.assertRaises(TypeError, binascii.crc_hqx, self.type2test(b''))
for crc in 0, 1, 0x1234, 0x12345, 0x12345678, -1:
self.assertEqual(binascii.crc_hqx(self.type2test(b''), crc),
crc & 0xffff)
def test_crc32(self):
crc = binascii.crc32(self.type2test(b"Test the CRC-32 of"))
crc = binascii.crc32(self.type2test(b" this string."), crc)
self.assertEqual(crc, 1571220330)
self.assertRaises(TypeError, binascii.crc32)
def test_hex(self):
# test hexlification
s = b'{s\005\000\000\000worldi\002\000\000\000s\005\000\000\000helloi\001\000\000\0000'
t = binascii.b2a_hex(self.type2test(s))
u = binascii.a2b_hex(self.type2test(t))
self.assertEqual(s, u)
self.assertRaises(binascii.Error, binascii.a2b_hex, t[:-1])
self.assertRaises(binascii.Error, binascii.a2b_hex, t[:-1] + b'q')
self.assertRaises(binascii.Error, binascii.a2b_hex, bytes([255, 255]))
self.assertRaises(binascii.Error, binascii.a2b_hex, b'0G')
self.assertRaises(binascii.Error, binascii.a2b_hex, b'0g')
self.assertRaises(binascii.Error, binascii.a2b_hex, b'G0')
self.assertRaises(binascii.Error, binascii.a2b_hex, b'g0')
# Confirm that b2a_hex == hexlify and a2b_hex == unhexlify
self.assertEqual(binascii.hexlify(self.type2test(s)), t)
self.assertEqual(binascii.unhexlify(self.type2test(t)), u)
@hypothesis.given(binary=hypothesis.strategies.binary())
def test_hex_roundtrip(self, binary):
converted = binascii.hexlify(self.type2test(binary))
restored = binascii.unhexlify(self.type2test(converted))
self.assertConversion(binary, converted, restored)
def test_hex_separator(self):
"""Test that hexlify and b2a_hex are binary versions of bytes.hex."""
# Logic of separators is tested in test_bytes.py. This checks that
# arg parsing works and exercises the direct to bytes object code
# path within pystrhex.c.
s = b'{s\005\000\000\000worldi\002\000\000\000s\005\000\000\000helloi\001\000\000\0000'
self.assertEqual(binascii.hexlify(self.type2test(s)), s.hex().encode('ascii'))
expected8 = s.hex('.', 8).encode('ascii')
self.assertEqual(binascii.hexlify(self.type2test(s), '.', 8), expected8)
expected1 = s.hex(':').encode('ascii')
self.assertEqual(binascii.b2a_hex(self.type2test(s), ':'), expected1)
def test_qp(self):
type2test = self.type2test
a2b_qp = binascii.a2b_qp
b2a_qp = binascii.b2a_qp
a2b_qp(data=b"", header=False) # Keyword arguments allowed
# A test for SF bug 534347 (segfaults without the proper fix)
try:
a2b_qp(b"", **{1:1})
except TypeError:
pass
else:
self.fail("binascii.a2b_qp(**{1:1}) didn't raise TypeError")
self.assertEqual(a2b_qp(type2test(b"=")), b"")
self.assertEqual(a2b_qp(type2test(b"= ")), b"= ")
self.assertEqual(a2b_qp(type2test(b"==")), b"=")
self.assertEqual(a2b_qp(type2test(b"=\nAB")), b"AB")
self.assertEqual(a2b_qp(type2test(b"=\r\nAB")), b"AB")
self.assertEqual(a2b_qp(type2test(b"=\rAB")), b"") # ?
self.assertEqual(a2b_qp(type2test(b"=\rAB\nCD")), b"CD") # ?
self.assertEqual(a2b_qp(type2test(b"=AB")), b"\xab")
self.assertEqual(a2b_qp(type2test(b"=ab")), b"\xab")
self.assertEqual(a2b_qp(type2test(b"=AX")), b"=AX")
self.assertEqual(a2b_qp(type2test(b"=XA")), b"=XA")
self.assertEqual(a2b_qp(type2test(b"=AB")[:-1]), b"=A")
self.assertEqual(a2b_qp(type2test(b'_')), b'_')
self.assertEqual(a2b_qp(type2test(b'_'), header=True), b' ')
self.assertRaises(TypeError, b2a_qp, foo="bar")
self.assertEqual(a2b_qp(type2test(b"=00\r\n=00")), b"\x00\r\n\x00")
self.assertEqual(b2a_qp(type2test(b"\xff\r\n\xff\n\xff")),
b"=FF\r\n=FF\r\n=FF")
self.assertEqual(b2a_qp(type2test(b"0"*75+b"\xff\r\n\xff\r\n\xff")),
b"0"*75+b"=\r\n=FF\r\n=FF\r\n=FF")
self.assertEqual(b2a_qp(type2test(b'\x7f')), b'=7F')
self.assertEqual(b2a_qp(type2test(b'=')), b'=3D')
self.assertEqual(b2a_qp(type2test(b'_')), b'_')
self.assertEqual(b2a_qp(type2test(b'_'), header=True), b'=5F')
self.assertEqual(b2a_qp(type2test(b'x y'), header=True), b'x_y')
self.assertEqual(b2a_qp(type2test(b'x '), header=True), b'x=20')
self.assertEqual(b2a_qp(type2test(b'x y'), header=True, quotetabs=True),
b'x=20y')
self.assertEqual(b2a_qp(type2test(b'x\ty'), header=True), b'x\ty')
self.assertEqual(b2a_qp(type2test(b' ')), b'=20')
self.assertEqual(b2a_qp(type2test(b'\t')), b'=09')
self.assertEqual(b2a_qp(type2test(b' x')), b' x')
self.assertEqual(b2a_qp(type2test(b'\tx')), b'\tx')
self.assertEqual(b2a_qp(type2test(b' x')[:-1]), b'=20')
self.assertEqual(b2a_qp(type2test(b'\tx')[:-1]), b'=09')
self.assertEqual(b2a_qp(type2test(b'\0')), b'=00')
self.assertEqual(b2a_qp(type2test(b'\0\n')), b'=00\n')
self.assertEqual(b2a_qp(type2test(b'\0\n'), quotetabs=True), b'=00\n')
self.assertEqual(b2a_qp(type2test(b'x y\tz')), b'x y\tz')
self.assertEqual(b2a_qp(type2test(b'x y\tz'), quotetabs=True),
b'x=20y=09z')
self.assertEqual(b2a_qp(type2test(b'x y\tz'), istext=False),
b'x y\tz')
self.assertEqual(b2a_qp(type2test(b'x \ny\t\n')),
b'x=20\ny=09\n')
self.assertEqual(b2a_qp(type2test(b'x \ny\t\n'), quotetabs=True),
b'x=20\ny=09\n')
self.assertEqual(b2a_qp(type2test(b'x \ny\t\n'), istext=False),
b'x =0Ay\t=0A')
self.assertEqual(b2a_qp(type2test(b'x \ry\t\r')),
b'x \ry\t\r')
self.assertEqual(b2a_qp(type2test(b'x \ry\t\r'), quotetabs=True),
b'x=20\ry=09\r')
self.assertEqual(b2a_qp(type2test(b'x \ry\t\r'), istext=False),
b'x =0Dy\t=0D')
self.assertEqual(b2a_qp(type2test(b'x \r\ny\t\r\n')),
b'x=20\r\ny=09\r\n')
self.assertEqual(b2a_qp(type2test(b'x \r\ny\t\r\n'), quotetabs=True),
b'x=20\r\ny=09\r\n')
self.assertEqual(b2a_qp(type2test(b'x \r\ny\t\r\n'), istext=False),
b'x =0D=0Ay\t=0D=0A')
self.assertEqual(b2a_qp(type2test(b'x \r\n')[:-1]), b'x \r')
self.assertEqual(b2a_qp(type2test(b'x\t\r\n')[:-1]), b'x\t\r')
self.assertEqual(b2a_qp(type2test(b'x \r\n')[:-1], quotetabs=True),
b'x=20\r')
self.assertEqual(b2a_qp(type2test(b'x\t\r\n')[:-1], quotetabs=True),
b'x=09\r')
self.assertEqual(b2a_qp(type2test(b'x \r\n')[:-1], istext=False),
b'x =0D')
self.assertEqual(b2a_qp(type2test(b'x\t\r\n')[:-1], istext=False),
b'x\t=0D')
self.assertEqual(b2a_qp(type2test(b'.')), b'=2E')
self.assertEqual(b2a_qp(type2test(b'.\n')), b'=2E\n')
self.assertEqual(b2a_qp(type2test(b'.\r')), b'=2E\r')
self.assertEqual(b2a_qp(type2test(b'.\0')), b'=2E=00')
self.assertEqual(b2a_qp(type2test(b'a.\n')), b'a.\n')
self.assertEqual(b2a_qp(type2test(b'.a')[:-1]), b'=2E')
@hypothesis.given(
binary=hypothesis.strategies.binary(),
quotetabs=hypothesis.strategies.booleans(),
istext=hypothesis.strategies.booleans(),
header=hypothesis.strategies.booleans(),
)
def test_b2a_qp_a2b_qp_round_trip(self, binary, quotetabs, istext, header):
converted = binascii.b2a_qp(
self.type2test(binary),
quotetabs=quotetabs, istext=istext, header=header,
)
restored = binascii.a2b_qp(self.type2test(converted), header=header)
self.assertConversion(binary, converted, restored,
quotetabs=quotetabs, istext=istext, header=header)
def test_empty_string(self):
# A test for SF bug #1022953. Make sure SystemError is not raised.
empty = self.type2test(b'')
for func in all_functions:
if func == 'crc_hqx':
# crc_hqx needs 2 arguments
binascii.crc_hqx(empty, 0)
continue
f = getattr(binascii, func)
try:
f(empty)
except Exception as err:
self.fail("{}({!r}) raises {!r}".format(func, empty, err))
def test_unicode_b2a(self):
# Unicode strings are not accepted by b2a_* functions.
for func in set(all_functions) - set(a2b_functions):
try:
self.assertRaises(TypeError, getattr(binascii, func), "test")
except Exception as err:
self.fail('{}("test") raises {!r}'.format(func, err))
# crc_hqx needs 2 arguments
self.assertRaises(TypeError, binascii.crc_hqx, "test", 0)
def test_unicode_a2b(self):
# Unicode strings are accepted by a2b_* functions.
MAX_ALL = 45
raw = self.rawdata[:MAX_ALL]
for fa, fb in zip(a2b_functions, b2a_functions):
a2b = getattr(binascii, fa)
b2a = getattr(binascii, fb)
try:
a = b2a(self.type2test(raw))
binary_res = a2b(a)
a = a.decode('ascii')
res = a2b(a)
except Exception as err:
self.fail("{}/{} conversion raises {!r}".format(fb, fa, err))
self.assertEqual(res, raw, "{}/{} conversion: "
"{!r} != {!r}".format(fb, fa, res, raw))
self.assertEqual(res, binary_res)
self.assertIsInstance(res, bytes)
# non-ASCII string
self.assertRaises(ValueError, a2b, "\x80")
def test_b2a_base64_newline(self):
# Issue #25357: test newline parameter
b = self.type2test(b'hello')
self.assertEqual(binascii.b2a_base64(b),
b'aGVsbG8=\n')
self.assertEqual(binascii.b2a_base64(b, newline=True),
b'aGVsbG8=\n')
self.assertEqual(binascii.b2a_base64(b, newline=False),
b'aGVsbG8=')
@hypothesis.given(
binary=hypothesis.strategies.binary(),
newline=hypothesis.strategies.booleans(),
)
def test_base64_roundtrip(self, binary, newline):
converted = binascii.b2a_base64(self.type2test(binary), newline=newline)
restored = binascii.a2b_base64(self.type2test(converted))
self.assertConversion(binary, converted, restored, newline=newline)
def test_c_contiguity(self):
m = memoryview(bytearray(b'noncontig'))
noncontig_writable = m[::-2]
with self.assertRaises(BufferError):
binascii.b2a_hex(noncontig_writable)
class ArrayBinASCIITest(BinASCIITest):
def type2test(self, s):
return array.array('B', list(s))
class BytearrayBinASCIITest(BinASCIITest):
type2test = bytearray
class MemoryviewBinASCIITest(BinASCIITest):
type2test = memoryview
class ChecksumBigBufferTestCase(unittest.TestCase):
"""bpo-38256 - check that inputs >=4 GiB are handled correctly."""
@bigmemtest(size=_4G + 4, memuse=1, dry_run=False)
def test_big_buffer(self, size):
data = b"nyan" * (_1G + 1)
self.assertEqual(binascii.crc32(data), 1044521549)
if __name__ == "__main__":
unittest.main()