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Bytes (which are the input for decoding) are mutable now. If a decoding 

error callback changes the bytes object in the exception the decoder might
use memory that's no longer in use. Change unicode_decode_call_errorhandler()
so that it fetches the adresses of the bytes array (start and end) from the
exception object and passes them back to the caller.
This commit is contained in:
Walter Dörwald 2007-07-30 13:31:40 +00:00
parent 2dbde5ea44
commit e78178e2c0
2 changed files with 68 additions and 19 deletions
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33
Lib/test/test_codeccallbacks.py
View File

@ -806,6 +806,39 @@ class CodecCallbackTest(unittest.TestCase):
text = 'abc<def>ghi'*n
text.translate(charmap)
def test_mutatingdecodehandler(self):
baddata = [
("ascii", b"\xff"),
("utf-7", b"++"),
("utf-8", b"\xff"),
("utf-16", b"\xff"),
("unicode-escape", b"\\u123g"),
("raw-unicode-escape", b"\\u123g"),
("unicode-internal", b"\xff"),
]
def replacing(exc):
if isinstance(exc, UnicodeDecodeError):
exc.object = 42
return ("\u4242", 0)
else:
raise TypeError("don't know how to handle %r" % exc)
codecs.register_error("test.replacing", replacing)
for (encoding, data) in baddata:
self.assertRaises(TypeError, data.decode, encoding, "test.replacing")
def mutating(exc):
if isinstance(exc, UnicodeDecodeError):
exc.object[:] = b""
return ("\u4242", 0)
else:
raise TypeError("don't know how to handle %r" % exc)
codecs.register_error("test.mutating", mutating)
# If the decoder doesn't pick up the modified input the following
# will lead to an endless loop
for (encoding, data) in baddata:
self.assertRaises(TypeError, data.decode, encoding, "test.replacing")
def test_main():
test.test_support.run_unittest(CodecCallbackTest)

54
Objects/unicodeobject.c
View File

@ -1269,7 +1269,7 @@ int PyUnicode_SetDefaultEncoding(const char *encoding)
static
int unicode_decode_call_errorhandler(const char *errors, PyObject **errorHandler,
const char *encoding, const char *reason,
const char *input, Py_ssize_t insize, Py_ssize_t *startinpos, Py_ssize_t *endinpos, PyObject **exceptionObject, const char **inptr,
const char **input, const char **inend, Py_ssize_t *startinpos, Py_ssize_t *endinpos, PyObject **exceptionObject, const char **inptr,
PyObject **output, Py_ssize_t *outpos, Py_UNICODE **outptr)
{
static char *argparse = "O!n;decoding error handler must return (unicode, int) tuple";
@ -1277,9 +1277,11 @@ int unicode_decode_call_errorhandler(const char *errors, PyObject **errorHandler
PyObject *restuple = NULL;
PyObject *repunicode = NULL;
Py_ssize_t outsize = PyUnicode_GET_SIZE(*output);
Py_ssize_t insize;
Py_ssize_t requiredsize;
Py_ssize_t newpos;
Py_UNICODE *repptr;
PyObject *inputobj = NULL;
Py_ssize_t repsize;
int res = -1;
@ -1291,7 +1293,7 @@ int unicode_decode_call_errorhandler(const char *errors, PyObject **errorHandler
if (*exceptionObject == NULL) {
*exceptionObject = PyUnicodeDecodeError_Create(
encoding, input, insize, *startinpos, *endinpos, reason);
encoding, *input, *inend-*input, *startinpos, *endinpos, reason);
if (*exceptionObject == NULL)
goto onError;
}
@ -1313,6 +1315,19 @@ int unicode_decode_call_errorhandler(const char *errors, PyObject **errorHandler
}
if (!PyArg_ParseTuple(restuple, argparse, &PyUnicode_Type, &repunicode, &newpos))
goto onError;
/* Copy back the bytes variables, which might have been modified by the
callback */
inputobj = PyUnicodeDecodeError_GetObject(*exceptionObject);
if (!inputobj)
goto onError;
if (!PyBytes_Check(inputobj)) {
PyErr_Format(PyExc_TypeError, "exception attribute object must be bytes");
}
*input = PyBytes_AS_STRING(inputobj);
insize = PyBytes_GET_SIZE(inputobj);
*inend = *input + insize;
if (newpos<0)
newpos = insize+newpos;
if (newpos<0 || newpos>insize) {
@ -1335,10 +1350,11 @@ int unicode_decode_call_errorhandler(const char *errors, PyObject **errorHandler
*outptr = PyUnicode_AS_UNICODE(*output) + *outpos;
}
*endinpos = newpos;
*inptr = input + newpos;
*inptr = *input + newpos;
Py_UNICODE_COPY(*outptr, repptr, repsize);
*outptr += repsize;
*outpos += repsize;
/* we made it! */
res = 0;
@ -1503,7 +1519,7 @@ PyObject *PyUnicode_DecodeUTF7(const char *s,
else if (SPECIAL(ch,0,0)) {
errmsg = "unexpected special character";
s++;
goto utf7Error;
goto utf7Error;
}
else {
*p++ = ch;
@ -1516,7 +1532,7 @@ PyObject *PyUnicode_DecodeUTF7(const char *s,
if (unicode_decode_call_errorhandler(
errors, &errorHandler,
"utf7", errmsg,
starts, size, &startinpos, &endinpos, &exc, &s,
&starts, &e, &startinpos, &endinpos, &exc, &s,
(PyObject **)&unicode, &outpos, &p))
goto onError;
}
@ -1527,7 +1543,7 @@ PyObject *PyUnicode_DecodeUTF7(const char *s,
if (unicode_decode_call_errorhandler(
errors, &errorHandler,
"utf7", "unterminated shift sequence",
starts, size, &startinpos, &endinpos, &exc, &s,
&starts, &e, &startinpos, &endinpos, &exc, &s,
(PyObject **)&unicode, &outpos, &p))
goto onError;
if (s < e)
@ -1848,7 +1864,7 @@ PyObject *PyUnicode_DecodeUTF8Stateful(const char *s,
if (unicode_decode_call_errorhandler(
errors, &errorHandler,
"utf8", errmsg,
starts, size, &startinpos, &endinpos, &exc, &s,
&starts, &e, &startinpos, &endinpos, &exc, &s,
(PyObject **)&unicode, &outpos, &p))
goto onError;
}
@ -2132,7 +2148,7 @@ PyUnicode_DecodeUTF16Stateful(const char *s,
if (unicode_decode_call_errorhandler(
errors, &errorHandler,
"utf16", errmsg,
starts, size, &startinpos, &endinpos, &exc, (const char **)&q,
&starts, (const char **)&e, &startinpos, &endinpos, &exc, (const char **)&q,
(PyObject **)&unicode, &outpos, &p))
goto onError;
}
@ -2342,7 +2358,7 @@ PyObject *PyUnicode_DecodeUnicodeEscape(const char *s,
if (unicode_decode_call_errorhandler(
errors, &errorHandler,
"unicodeescape", "end of string in escape sequence",
starts, size, &startinpos, &endinpos, &exc, &s,
&starts, &end, &startinpos, &endinpos, &exc, &s,
(PyObject **)&v, &outpos, &p))
goto onError;
goto nextByte;
@ -2354,7 +2370,7 @@ PyObject *PyUnicode_DecodeUnicodeEscape(const char *s,
if (unicode_decode_call_errorhandler(
errors, &errorHandler,
"unicodeescape", message,
starts, size, &startinpos, &endinpos, &exc, &s,
&starts, &end, &startinpos, &endinpos, &exc, &s,
(PyObject **)&v, &outpos, &p))
goto onError;
goto nextByte;
@ -2393,7 +2409,7 @@ PyObject *PyUnicode_DecodeUnicodeEscape(const char *s,
if (unicode_decode_call_errorhandler(
errors, &errorHandler,
"unicodeescape", "illegal Unicode character",
starts, size, &startinpos, &endinpos, &exc, &s,
&starts, &end, &startinpos, &endinpos, &exc, &s,
(PyObject **)&v, &outpos, &p))
goto onError;
}
@ -2435,7 +2451,7 @@ PyObject *PyUnicode_DecodeUnicodeEscape(const char *s,
if (unicode_decode_call_errorhandler(
errors, &errorHandler,
"unicodeescape", message,
starts, size, &startinpos, &endinpos, &exc, &s,
&starts, &end, &startinpos, &endinpos, &exc, &s,
(PyObject **)&v, &outpos, &p))
goto onError;
break;
@ -2449,7 +2465,7 @@ PyObject *PyUnicode_DecodeUnicodeEscape(const char *s,
if (unicode_decode_call_errorhandler(
errors, &errorHandler,
"unicodeescape", message,
starts, size, &startinpos, &endinpos, &exc, &s,
&starts, &end, &startinpos, &endinpos, &exc, &s,
(PyObject **)&v, &outpos, &p))
goto onError;
}
@ -2728,7 +2744,7 @@ PyObject *PyUnicode_DecodeRawUnicodeEscape(const char *s,
if (unicode_decode_call_errorhandler(
errors, &errorHandler,
"rawunicodeescape", "truncated \\uXXXX",
starts, size, &startinpos, &endinpos, &exc, &s,
&starts, &end, &startinpos, &endinpos, &exc, &s,
(PyObject **)&v, &outpos, &p))
goto onError;
goto nextByte;
@ -2746,7 +2762,7 @@ PyObject *PyUnicode_DecodeRawUnicodeEscape(const char *s,
if (unicode_decode_call_errorhandler(
errors, &errorHandler,
"rawunicodeescape", "\\Uxxxxxxxx out of range",
starts, size, &startinpos, &endinpos, &exc, &s,
&starts, &end, &startinpos, &endinpos, &exc, &s,
(PyObject **)&v, &outpos, &p))
goto onError;
}
@ -2897,7 +2913,7 @@ PyObject *_PyUnicode_DecodeUnicodeInternal(const char *s,
if (unicode_decode_call_errorhandler(
errors, &errorHandler,
"unicode_internal", reason,
starts, size, &startinpos, &endinpos, &exc, &s,
&starts, &end, &startinpos, &endinpos, &exc, &s,
(PyObject **)&v, &outpos, &p)) {
goto onError;
}
@ -3277,7 +3293,7 @@ PyObject *PyUnicode_DecodeASCII(const char *s,
if (unicode_decode_call_errorhandler(
errors, &errorHandler,
"ascii", "ordinal not in range(128)",
starts, size, &startinpos, &endinpos, &exc, &s,
&starts, &e, &startinpos, &endinpos, &exc, &s,
(PyObject **)&v, &outpos, &p))
goto onError;
}
@ -3578,7 +3594,7 @@ PyObject *PyUnicode_DecodeCharmap(const char *s,
if (unicode_decode_call_errorhandler(
errors, &errorHandler,
"charmap", "character maps to <undefined>",
starts, size, &startinpos, &endinpos, &exc, &s,
&starts, &e, &startinpos, &endinpos, &exc, &s,
(PyObject **)&v, &outpos, &p)) {
goto onError;
}
@ -3628,7 +3644,7 @@ PyObject *PyUnicode_DecodeCharmap(const char *s,
if (unicode_decode_call_errorhandler(
errors, &errorHandler,
"charmap", "character maps to <undefined>",
starts, size, &startinpos, &endinpos, &exc, &s,
&starts, &e, &startinpos, &endinpos, &exc, &s,
(PyObject **)&v, &outpos, &p)) {
Py_DECREF(x);
goto onError;