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Issue #16743: Fix mmap overflow check on 32 bit Windows

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This commit is contained in:
Richard Oudkerk 2013-02-13 12:18:03 +00:00
parent 7e0191170e
commit 0d09ba8e0b
2 changed files with 18 additions and 11 deletions
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7
Lib/test/test_mmap.py
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@ -693,6 +693,13 @@ class LargeMmapTests(unittest.TestCase):
def test_large_filesize(self): def test_large_filesize(self):
with self._make_test_file(0x17FFFFFFF, b" ") as f: with self._make_test_file(0x17FFFFFFF, b" ") as f:
if sys.maxsize < 0x180000000:
# On 32 bit platforms the file is larger than sys.maxsize so
# mapping the whole file should fail -- Issue #16743
with self.assertRaises(OverflowError):
mmap.mmap(f.fileno(), 0x180000000, access=mmap.ACCESS_READ)
with self.assertRaises(ValueError):
mmap.mmap(f.fileno(), 0, access=mmap.ACCESS_READ)
with mmap.mmap(f.fileno(), 0x10000, access=mmap.ACCESS_READ) as m: with mmap.mmap(f.fileno(), 0x10000, access=mmap.ACCESS_READ) as m:
self.assertEqual(m.size(), 0x180000000) self.assertEqual(m.size(), 0x180000000)

22
Modules/mmapmodule.c
View File

@ -1140,7 +1140,6 @@ new_mmap_object(PyTypeObject *type, PyObject *args, PyObject *kwdict)
# endif # endif
if (fd != -1 && fstat(fd, &st) == 0 && S_ISREG(st.st_mode)) { if (fd != -1 && fstat(fd, &st) == 0 && S_ISREG(st.st_mode)) {
if (map_size == 0) { if (map_size == 0) {
off_t calc_size;
if (st.st_size == 0) { if (st.st_size == 0) {
PyErr_SetString(PyExc_ValueError, PyErr_SetString(PyExc_ValueError,
"cannot mmap an empty file"); "cannot mmap an empty file");
@ -1151,13 +1150,12 @@ new_mmap_object(PyTypeObject *type, PyObject *args, PyObject *kwdict)
"mmap offset is greater than file size"); "mmap offset is greater than file size");
return NULL; return NULL;
} }
calc_size = st.st_size - offset; if (st.st_size - offset > PY_SSIZE_T_MAX) {
map_size = calc_size;
if (map_size != calc_size) {
PyErr_SetString(PyExc_ValueError, PyErr_SetString(PyExc_ValueError,
"mmap length is too large"); "mmap length is too large");
return NULL; return NULL;
} }
map_size = (Py_ssize_t) (st.st_size - offset);
} else if (offset + (size_t)map_size > st.st_size) { } else if (offset + (size_t)map_size > st.st_size) {
PyErr_SetString(PyExc_ValueError, PyErr_SetString(PyExc_ValueError,
"mmap length is greater than file size"); "mmap length is greater than file size");
@ -1354,11 +1352,13 @@ new_mmap_object(PyTypeObject *type, PyObject *args, PyObject *kwdict)
Py_DECREF(m_obj); Py_DECREF(m_obj);
return NULL; return NULL;
} }
if (offset - size > PY_SSIZE_T_MAX) if (size - offset > PY_SSIZE_T_MAX) {
/* Map area too large to fit in memory */ PyErr_SetString(PyExc_ValueError,
m_obj->size = (Py_ssize_t) -1; "mmap length is too large");
else Py_DECREF(m_obj);
m_obj->size = (Py_ssize_t) (size - offset); return NULL;
}
m_obj->size = (Py_ssize_t) (size - offset);
} else { } else {
m_obj->size = map_size; m_obj->size = map_size;
size = offset + map_size; size = offset + map_size;