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[3.13] gh-123378: fix a crash in UnicodeError.__str__ (GH-124935) #125099

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Merged
merged 1 commit into from
Oct 8, 2024
Merged

[3.13] gh-123378: fix a crash in UnicodeError.__str__ (GH-124935) #125099

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24 changes: 24 additions & 0 deletions Lib/test/test_exceptions.py
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Original file line number Diff line number Diff line change
Expand Up @@ -8,6 +8,7 @@
import weakref
import errno
from codecs import BOM_UTF8
from itertools import product
from textwrap import dedent

from test.support import (captured_stderr, check_impl_detail,
Expand Down Expand Up @@ -1336,6 +1337,29 @@ def test_unicode_errors_no_object(self):
for klass in klasses:
self.assertEqual(str(klass.__new__(klass)), "")

def test_unicode_error_str_does_not_crash(self):
# Test that str(UnicodeError(...)) does not crash.
# See https://github.com/python/cpython/issues/123378.

for start, end, objlen in product(
range(-5, 5),
range(-5, 5),
range(7),
):
obj = 'a' * objlen
with self.subTest('encode', objlen=objlen, start=start, end=end):
exc = UnicodeEncodeError('utf-8', obj, start, end, '')
self.assertIsInstance(str(exc), str)

with self.subTest('translate', objlen=objlen, start=start, end=end):
exc = UnicodeTranslateError(obj, start, end, '')
self.assertIsInstance(str(exc), str)

encoded = obj.encode()
with self.subTest('decode', objlen=objlen, start=start, end=end):
exc = UnicodeDecodeError('utf-8', encoded, start, end, '')
self.assertIsInstance(str(exc), str)

@no_tracing
def test_badisinstance(self):
# Bug #2542: if issubclass(e, MyException) raises an exception,
Expand Down
3 changes: 3 additions & 0 deletions Misc/NEWS.d/next/Core_and_Builtins/2024-10-03-14-39-41.gh-issue-123378.dCxANf.rst
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Original file line number Diff line number Diff line change
@@ -0,0 +1,3 @@
Fix a crash in the :meth:`~object.__str__` method of :exc:`UnicodeError`
objects when the :attr:`UnicodeError.start` and :attr:`UnicodeError.end`
values are invalid or out-of-range. Patch by Bénédikt Tran.
111 changes: 66 additions & 45 deletions Objects/exceptions.c
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Original file line number Diff line number Diff line change
Expand Up @@ -2959,46 +2959,55 @@ UnicodeEncodeError_init(PyObject *self, PyObject *args, PyObject *kwds)
static PyObject *
UnicodeEncodeError_str(PyObject *self)
{
PyUnicodeErrorObject *uself = (PyUnicodeErrorObject *)self;
PyUnicodeErrorObject *exc = (PyUnicodeErrorObject *)self;
PyObject *result = NULL;
PyObject *reason_str = NULL;
PyObject *encoding_str = NULL;

if (!uself->object)
if (exc->object == NULL) {
/* Not properly initialized. */
return PyUnicode_FromString("");
}

/* Get reason and encoding as strings, which they might not be if
they've been modified after we were constructed. */
reason_str = PyObject_Str(uself->reason);
if (reason_str == NULL)
reason_str = PyObject_Str(exc->reason);
if (reason_str == NULL) {
goto done;
encoding_str = PyObject_Str(uself->encoding);
if (encoding_str == NULL)
}
encoding_str = PyObject_Str(exc->encoding);
if (encoding_str == NULL) {
goto done;
}

Py_ssize_t len = PyUnicode_GET_LENGTH(exc->object);
Py_ssize_t start = exc->start, end = exc->end;

if (uself->start < PyUnicode_GET_LENGTH(uself->object) && uself->end == uself->start+1) {
Py_UCS4 badchar = PyUnicode_ReadChar(uself->object, uself->start);
if ((start >= 0 && start < len) && (end >= 0 && end <= len) && end == start + 1) {
Py_UCS4 badchar = PyUnicode_ReadChar(exc->object, start);
const char *fmt;
if (badchar <= 0xff)
if (badchar <= 0xff) {
fmt = "'%U' codec can't encode character '\\x%02x' in position %zd: %U";
else if (badchar <= 0xffff)
}
else if (badchar <= 0xffff) {
fmt = "'%U' codec can't encode character '\\u%04x' in position %zd: %U";
else
}
else {
fmt = "'%U' codec can't encode character '\\U%08x' in position %zd: %U";
}
result = PyUnicode_FromFormat(
fmt,
encoding_str,
(int)badchar,
uself->start,
start,
reason_str);
}
else {
result = PyUnicode_FromFormat(
"'%U' codec can't encode characters in position %zd-%zd: %U",
encoding_str,
uself->start,
uself->end-1,
start,
end - 1,
reason_str);
}
done:
Expand Down Expand Up @@ -3072,41 +3081,46 @@ UnicodeDecodeError_init(PyObject *self, PyObject *args, PyObject *kwds)
static PyObject *
UnicodeDecodeError_str(PyObject *self)
{
PyUnicodeErrorObject *uself = (PyUnicodeErrorObject *)self;
PyUnicodeErrorObject *exc = (PyUnicodeErrorObject *)self;
PyObject *result = NULL;
PyObject *reason_str = NULL;
PyObject *encoding_str = NULL;

if (!uself->object)
if (exc->object == NULL) {
/* Not properly initialized. */
return PyUnicode_FromString("");
}

/* Get reason and encoding as strings, which they might not be if
they've been modified after we were constructed. */
reason_str = PyObject_Str(uself->reason);
if (reason_str == NULL)
reason_str = PyObject_Str(exc->reason);
if (reason_str == NULL) {
goto done;
encoding_str = PyObject_Str(uself->encoding);
if (encoding_str == NULL)
}
encoding_str = PyObject_Str(exc->encoding);
if (encoding_str == NULL) {
goto done;
}

Py_ssize_t len = PyBytes_GET_SIZE(exc->object);
Py_ssize_t start = exc->start, end = exc->end;

if (uself->start < PyBytes_GET_SIZE(uself->object) && uself->end == uself->start+1) {
int byte = (int)(PyBytes_AS_STRING(((PyUnicodeErrorObject *)self)->object)[uself->start]&0xff);
if ((start >= 0 && start < len) && (end >= 0 && end <= len) && end == start + 1) {
int badbyte = (int)(PyBytes_AS_STRING(exc->object)[start] & 0xff);
result = PyUnicode_FromFormat(
"'%U' codec can't decode byte 0x%02x in position %zd: %U",
encoding_str,
byte,
uself->start,
badbyte,
start,
reason_str);
}
else {
result = PyUnicode_FromFormat(
"'%U' codec can't decode bytes in position %zd-%zd: %U",
encoding_str,
uself->start,
uself->end-1,
reason_str
);
start,
end - 1,
reason_str);
}
done:
Py_XDECREF(reason_str);
Expand Down Expand Up @@ -3169,42 +3183,49 @@ UnicodeTranslateError_init(PyUnicodeErrorObject *self, PyObject *args,
static PyObject *
UnicodeTranslateError_str(PyObject *self)
{
PyUnicodeErrorObject *uself = (PyUnicodeErrorObject *)self;
PyUnicodeErrorObject *exc = (PyUnicodeErrorObject *)self;
PyObject *result = NULL;
PyObject *reason_str = NULL;

if (!uself->object)
if (exc->object == NULL) {
/* Not properly initialized. */
return PyUnicode_FromString("");
}

/* Get reason as a string, which it might not be if it's been
modified after we were constructed. */
reason_str = PyObject_Str(uself->reason);
if (reason_str == NULL)
reason_str = PyObject_Str(exc->reason);
if (reason_str == NULL) {
goto done;
}

Py_ssize_t len = PyUnicode_GET_LENGTH(exc->object);
Py_ssize_t start = exc->start, end = exc->end;

if (uself->start < PyUnicode_GET_LENGTH(uself->object) && uself->end == uself->start+1) {
Py_UCS4 badchar = PyUnicode_ReadChar(uself->object, uself->start);
if ((start >= 0 && start < len) && (end >= 0 && end <= len) && end == start + 1) {
Py_UCS4 badchar = PyUnicode_ReadChar(exc->object, start);
const char *fmt;
if (badchar <= 0xff)
if (badchar <= 0xff) {
fmt = "can't translate character '\\x%02x' in position %zd: %U";
else if (badchar <= 0xffff)
}
else if (badchar <= 0xffff) {
fmt = "can't translate character '\\u%04x' in position %zd: %U";
else
}
else {
fmt = "can't translate character '\\U%08x' in position %zd: %U";
}
result = PyUnicode_FromFormat(
fmt,
(int)badchar,
uself->start,
reason_str
);
} else {
start,
reason_str);
}
else {
result = PyUnicode_FromFormat(
"can't translate characters in position %zd-%zd: %U",
uself->start,
uself->end-1,
reason_str
);
start,
end - 1,
reason_str);
}
done:
Py_XDECREF(reason_str);
Expand Down
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