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gh-148029: Fix error message for invalid number of Base32 characters #148030

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Merged
serhiy-storchaka merged 2 commits into from
Apr 4, 2026
+33 −11
Merged

gh-148029: Fix error message for invalid number of Base32 characters #148030

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b4aaff2
gh-148029: Fix error message for invalid number of Base32 characters
serhiy-storchaka Apr 3, 2026
e43a139
Merge branch 'main' into base32-invalid-length
serhiy-storchaka Apr 3, 2026
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40 changes: 31 additions & 9 deletions Lib/test/test_binascii.py
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Original file line number Diff line number Diff line change
Expand Up @@ -159,14 +159,14 @@ def addnoise(line):
def test_base64_bad_padding(self):
# Test malformed padding
def _assertRegexTemplate(assert_regex, data,
non_strict_mode_expected_result):
non_strict_mode_expected_result, **kwargs):
data = self.type2test(data)
with self.assertRaisesRegex(binascii.Error, assert_regex):
binascii.a2b_base64(data, strict_mode=True)
binascii.a2b_base64(data, strict_mode=True, **kwargs)
self.assertEqual(binascii.a2b_base64(data, strict_mode=False),
non_strict_mode_expected_result)
self.assertEqual(binascii.a2b_base64(data, strict_mode=True,
ignorechars=b'='),
ignorechars=b' ='),
non_strict_mode_expected_result)
self.assertEqual(binascii.a2b_base64(data),
non_strict_mode_expected_result)
Expand All @@ -180,8 +180,11 @@ def assertDiscontinuousPadding(*args):
def assertExcessPadding(*args):
_assertRegexTemplate(r'(?i)Excess padding', *args)

def assertInvalidLength(*args):
_assertRegexTemplate(r'(?i)Invalid.+number of data characters', *args)
def assertInvalidLength(data, *args, length=None, **kwargs):
if length is None:
length = len(data.split(b'=', 1)[0].replace(b' ', b''))
assert_regex = fr"(?i)Invalid.+number of data characters \({length}\)"
_assertRegexTemplate(assert_regex, data, *args, **kwargs)

assertExcessPadding(b'ab===', b'i')
assertExcessPadding(b'ab====', b'i')
Expand All @@ -206,6 +209,9 @@ def assertInvalidLength(*args):
assertInvalidLength(b'a=bc==', b'i\xb7')
assertInvalidLength(b'a=bcd', b'i\xb7\x1d')
assertInvalidLength(b'a=bcd=', b'i\xb7\x1d')
assertInvalidLength(b' a=b==', b'i', ignorechars=b' ')
assertInvalidLength(b'abcde=f==', b'i\xb7\x1dy')
assertInvalidLength(b' abcde=f==', b'i\xb7\x1dy', ignorechars=b' ')

assertDiscontinuousPadding(b'ab=c=', b'i\xb7')
assertDiscontinuousPadding(b'ab=cd', b'i\xb7\x1d')
Expand Down Expand Up @@ -763,9 +769,9 @@ def _fixPadding(data):
p = 8 - len_8 if len_8 else 0
return fixed + b"=" * p

def _assertRegexTemplate(assert_regex, data, good_padding_result=None):
def _assertRegexTemplate(assert_regex, data, good_padding_result=None, **kwargs):
with self.assertRaisesRegex(binascii.Error, assert_regex):
binascii.a2b_base32(self.type2test(data))
binascii.a2b_base32(self.type2test(data), **kwargs)
if good_padding_result:
fixed = self.type2test(_fixPadding(data))
self.assertEqual(binascii.a2b_base32(fixed), good_padding_result)
Expand All @@ -788,8 +794,11 @@ def assertIncorrectPadding(*args):
def assertDiscontinuousPadding(*args):
_assertRegexTemplate(r"(?i)Discontinuous padding", *args)

def assertInvalidLength(*args):
_assertRegexTemplate(r"(?i)Invalid.+number of data characters", *args)
def assertInvalidLength(data, *args, length=None, **kwargs):
if length is None:
length = len(data.split(b'=', 1)[0].replace(b' ', b''))
assert_regex = fr"(?i)Invalid.+number of data characters \({length}\)"
_assertRegexTemplate(assert_regex, data, *args, **kwargs)

assertNonBase32Data(b"a")
assertNonBase32Data(b"AA-")
Expand Down Expand Up @@ -869,6 +878,9 @@ def assertInvalidLength(*args):
assertInvalidLength(b"A")
assertInvalidLength(b"ABC")
assertInvalidLength(b"ABCDEF")
assertInvalidLength(b"ABCDEFGHI")
assertInvalidLength(b"ABCDEFGHIJK")
assertInvalidLength(b"ABCDEFGHIJKLMN")

assertInvalidLength(b"A=")
assertInvalidLength(b"A==")
Expand All @@ -889,6 +901,16 @@ def assertInvalidLength(*args):
assertInvalidLength(b"BEEFCA=K", b"\t\x08Q\x01")
assertInvalidLength(b"BEEFCA=====K", b"\t\x08Q\x01")

assertInvalidLength(b" A", ignorechars=b' ')
assertInvalidLength(b" ABC", ignorechars=b' ')
assertInvalidLength(b" ABCDEF", ignorechars=b' ')
assertInvalidLength(b" ABCDEFGHI", ignorechars=b' ')
assertInvalidLength(b" ABCDEFGHIJK", ignorechars=b' ')
assertInvalidLength(b" ABCDEFGHIJKLMN", ignorechars=b' ')
assertInvalidLength(b" A=======", ignorechars=b' ')
assertInvalidLength(b" ABC=====", ignorechars=b' ')
assertInvalidLength(b" ABCDEF==", ignorechars=b' ')

def test_base32_wrapcol(self):
self._common_test_wrapcol(binascii.b2a_base32)
b = self.type2test(b'www.python.org')
Expand Down
4 changes: 2 additions & 2 deletions Modules/binascii.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1680,12 +1680,12 @@ binascii_a2b_base32_impl(PyObject *module, Py_buffer *data,
if (octa_pos == 1 || octa_pos == 3 || octa_pos == 6) {
state = get_binascii_state(module);
if (state) {
const unsigned char *ascii_data_start = data->buf;
unsigned char *bin_data_start = PyBytesWriter_GetData(writer);
PyErr_Format(state->Error,
"Invalid base32-encoded string: "
"number of data characters (%zd) "
"cannot be 1, 3, or 6 more than a multiple of 8",
ascii_data - ascii_data_start);
(bin_data - bin_data_start) / 5 * 8 + octa_pos);
}
goto error;
}
Expand Down
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