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filterstring() and filterunicode() in Python/bltinmodule.c

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blindly assumed that tp_as_sequence->sq_item always returns
a str or unicode object. This might fail with str or unicode
subclasses.

This patch checks whether the object returned from __getitem__
is a str/unicode object and raises a TypeError if not (and
the filter function returned true).

Furthermore the result for __getitem__ can be more than one
character long, so checks for enough memory have to be done.
This commit is contained in:
Walter Dörwald 2003-02-04 16:28:00 +00:00
parent 57ba55b77d
commit 903f1e0c40
2 changed files with 91 additions and 8 deletions
Download patch file Download diff file Expand all files Collapse all files

21
Lib/test/test_builtin.py
View file

@ -367,6 +367,16 @@ class BuiltinTest(unittest.TestCase):
raise ValueError
self.assertRaises(ValueError, filter, lambda x: x >="3", badstr("1234"))
class badstr2(str):
def __getitem__(self, index):
return 42
self.assertRaises(TypeError, filter, lambda x: x >=42, badstr2("1234"))
class weirdstr(str):
def __getitem__(self, index):
return weirdstr(2*str.__getitem__(self, index))
self.assertEqual(filter(lambda x: x>="33", weirdstr("1234")), "3344")
if have_unicode:
# test bltinmodule.c::filterunicode()
self.assertEqual(filter(None, unicode("12")), unicode("12"))
@ -374,6 +384,17 @@ class BuiltinTest(unittest.TestCase):
self.assertRaises(TypeError, filter, 42, unicode("12"))
self.assertRaises(ValueError, filter, lambda x: x >="3", badstr(unicode("1234")))
class badunicode(unicode):
def __getitem__(self, index):
return 42
self.assertRaises(TypeError, filter, lambda x: x >=42, badunicode("1234"))
class weirdunicode(unicode):
def __getitem__(self, index):
return weirdunicode(2*unicode.__getitem__(self, index))
self.assertEqual(
filter(lambda x: x>=unicode("33"), weirdunicode("1234")), unicode("3344"))
def test_float(self):
self.assertEqual(float(3.14), 3.14)
self.assertEqual(float(314), 314.0)

78
Python/bltinmodule.c
View file

@ -1892,6 +1892,7 @@ filterstring(PyObject *func, PyObject *strobj)
PyObject *result;
register int i, j;
int len = PyString_Size(strobj);
int outlen = len;
if (func == Py_None) {
/* No character is ever false -- share input string */
@ -1921,13 +1922,43 @@ filterstring(PyObject *func, PyObject *strobj)
}
ok = PyObject_IsTrue(good);
Py_DECREF(good);
if (ok)
PyString_AS_STRING((PyStringObject *)result)[j++] =
PyString_AS_STRING((PyStringObject *)item)[0];
if (ok) {
int reslen;
if (!PyString_Check(item)) {
PyErr_SetString(PyExc_TypeError, "can't filter str to str:"
" __getitem__ returned different type");
Py_DECREF(item);
goto Fail_1;
}
reslen = PyString_GET_SIZE(item);
if (reslen == 1) {
PyString_AS_STRING(result)[j++] =
PyString_AS_STRING(item)[0];
} else {
/* do we need more space? */
int need = j + reslen + len-i-1;
if (need > outlen) {
/* overallocate, to avoid reallocations */
if (need<2*outlen)
need = 2*outlen;
if (_PyString_Resize(&result, need)) {
Py_DECREF(item);
return NULL;
}
outlen = need;
}
memcpy(
PyString_AS_STRING(result) + j,
PyString_AS_STRING(item),
reslen
);
j += reslen;
}
}
Py_DECREF(item);
}
if (j < len)
if (j < outlen)
_PyString_Resize(&result, j);
return result;
@ -1946,6 +1977,7 @@ filterunicode(PyObject *func, PyObject *strobj)
PyObject *result;
register int i, j;
int len = PyUnicode_GetSize(strobj);
int outlen = len;
if (func == Py_None) {
/* No character is ever false -- share input string */
@ -1975,13 +2007,43 @@ filterunicode(PyObject *func, PyObject *strobj)
}
ok = PyObject_IsTrue(good);
Py_DECREF(good);
if (ok)
PyUnicode_AS_UNICODE((PyStringObject *)result)[j++] =
PyUnicode_AS_UNICODE((PyStringObject *)item)[0];
if (ok) {
int reslen;
if (!PyUnicode_Check(item)) {
PyErr_SetString(PyExc_TypeError, "can't filter unicode to unicode:"
" __getitem__ returned different type");
Py_DECREF(item);
goto Fail_1;
}
reslen = PyUnicode_GET_SIZE(item);
if (reslen == 1) {
PyUnicode_AS_UNICODE(result)[j++] =
PyUnicode_AS_UNICODE(item)[0];
} else {
/* do we need more space? */
int need = j + reslen + len-i-1;
if (need > outlen) {
/* overallocate, to avoid reallocations */
if (need<2*outlen)
need = 2*outlen;
if (PyUnicode_Resize(&result, need)) {
Py_DECREF(item);
return NULL;
}
outlen = need;
}
memcpy(
PyUnicode_AS_UNICODE(result) + j,
PyUnicode_AS_UNICODE(item),
reslen*sizeof(Py_UNICODE)
);
j += reslen;
}
}
Py_DECREF(item);
}
if (j < len)
if (j < outlen)
PyUnicode_Resize(&result, j);
return result;