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gh-92888: Fix memoryview bad __index__ use after free #92946

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Merged
Fidget-Spinner merged 12 commits into from
Jun 17, 2022
Merged

gh-92888: Fix memoryview bad __index__ use after free #92946

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73ffb29
Fix memoryview bad `__index__` use after free
Fidget-Spinner May 19, 2022
3581de7
📜🤖 Added by blurb_it.
blurb-it[bot] May 19, 2022
43c66d6
stylistic nits
Fidget-Spinner May 19, 2022
18b921f
Merge branch 'fix_memoryview_auf' of https://github.com/Fidget-Spinne…
Fidget-Spinner May 20, 2022
2f3c04f
Fix whitespace
Fidget-Spinner May 21, 2022
a250b02
Use more comprehensive tests by Serhiy
Fidget-Spinner May 23, 2022
c818990
Add more tests by Serhiy
Fidget-Spinner May 23, 2022
42a706c
Fix newline
Fidget-Spinner May 23, 2022
b650764
Fix for tuple index
Fidget-Spinner May 23, 2022
47bd91f
Address review
Fidget-Spinner May 23, 2022
6890713
Address Victor's review
Fidget-Spinner May 29, 2022
d3edf74
re-add ba=None
Fidget-Spinner May 30, 2022
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Fix for tuple index
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@Fidget-Spinner
Fidget-Spinner committed May 23, 2022
commit b6507642e25d462b48e27eb12f65c42de34787b0
11 changes: 7 additions & 4 deletions Lib/test/test_memoryview.py
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Original file line number Diff line number Diff line change
Expand Up @@ -579,10 +579,13 @@ def __bool__(self):

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ba = None
m = memoryview(bytearray(b'\xff'*size)).cast('B', (64, 2))
self.assertEqual(m[MyIndex(), 0], 0)
with self.assertRaisesRegex(ValueError, "operation forbidden"):
m[MyIndex(), 0]

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ba = None
m = memoryview(bytearray(b'\xff'*size)).cast('B', (2, 64))
self.assertEqual(m[0, MyIndex()], 0)
with self.assertRaisesRegex(ValueError, "operation forbidden"):
m[0, MyIndex()], 0
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ba = None
m = memoryview(bytearray(b'\xff'*size))
Expand All @@ -592,13 +595,13 @@ def __bool__(self):

ba = None
m = memoryview(bytearray(b'\xff'*size))
with self.assertRaisesRegex(ValueError, "operation forbidden"):
with self.assertRaisesRegex(ValueError, "operation forbidden"):
m[:MyIndex()] = b'spam'
self.assertEqual(ba[:8], b'\0'*8)

ba = None
m = memoryview(bytearray(b'\xff'*size))
with self.assertRaisesRegex(ValueError, "operation forbidden"):
with self.assertRaisesRegex(ValueError, "operation forbidden"):
m[MyIndex():8] = b'spam'
self.assertEqual(ba[:8], b'\0'*8)

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Expand Down
31 changes: 17 additions & 14 deletions Objects/memoryobject.c
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Expand Up @@ -1678,7 +1678,7 @@ pylong_as_zu(PyObject *item)
module syntax. This function is very sensitive to small changes. With this
layout gcc automatically generates a fast jump table. */
static inline PyObject *
unpack_single(const char *ptr, const char *fmt)
unpack_single(PyMemoryViewObject *self, const char *ptr, const char *fmt)
{
unsigned long long llu;
unsigned long lu;
Expand All @@ -1690,6 +1690,8 @@ unpack_single(const char *ptr, const char *fmt)
unsigned char uc;
void *p;

CHECK_RELEASED(self); /* See gh-92888 for why we need this here */
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switch (fmt[0]) {

/* signed integers and fast path for 'B' */
Expand Down Expand Up @@ -1779,6 +1781,8 @@ pack_single(PyMemoryViewObject *self, char *ptr, PyObject *item, const char *fmt
double d;
void *p;

CHECK_RELEASED_INT(self); /* See gh-92888 for why we need this here */
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switch (fmt[0]) {
/* signed integers */
case 'b': case 'h': case 'i': case 'l':
Expand Down Expand Up @@ -2058,7 +2062,7 @@ adjust_fmt(const Py_buffer *view)

/* Base case for multi-dimensional unpacking. Assumption: ndim == 1. */
static PyObject *
tolist_base(const char *ptr, const Py_ssize_t *shape,
tolist_base(PyMemoryViewObject *self, const char *ptr, const Py_ssize_t *shape,
const Py_ssize_t *strides, const Py_ssize_t *suboffsets,
const char *fmt)
{
Expand All @@ -2071,7 +2075,7 @@ tolist_base(const char *ptr, const Py_ssize_t *shape,

for (i = 0; i < shape[0]; ptr+=strides[0], i++) {
const char *xptr = ADJUST_PTR(ptr, suboffsets, 0);
item = unpack_single(xptr, fmt);
item = unpack_single(self, xptr, fmt);
if (item == NULL) {
Py_DECREF(lst);
return NULL;
Expand All @@ -2085,7 +2089,7 @@ tolist_base(const char *ptr, const Py_ssize_t *shape,
/* Unpack a multi-dimensional array into a nested list.
Assumption: ndim >= 1. */
static PyObject *
tolist_rec(const char *ptr, Py_ssize_t ndim, const Py_ssize_t *shape,
tolist_rec(PyMemoryViewObject *self, const char *ptr, Py_ssize_t ndim, const Py_ssize_t *shape,
const Py_ssize_t *strides, const Py_ssize_t *suboffsets,
const char *fmt)
{
Expand All @@ -2097,15 +2101,15 @@ tolist_rec(const char *ptr, Py_ssize_t ndim, const Py_ssize_t *shape,
assert(strides != NULL);

if (ndim == 1)
return tolist_base(ptr, shape, strides, suboffsets, fmt);
return tolist_base(self, ptr, shape, strides, suboffsets, fmt);

lst = PyList_New(shape[0]);
if (lst == NULL)
return NULL;

for (i = 0; i < shape[0]; ptr+=strides[0], i++) {
const char *xptr = ADJUST_PTR(ptr, suboffsets, 0);
item = tolist_rec(xptr, ndim-1, shape+1,
item = tolist_rec(self, xptr, ndim-1, shape+1,
strides+1, suboffsets ? suboffsets+1 : NULL,
fmt);
if (item == NULL) {
Expand Down Expand Up @@ -2139,15 +2143,15 @@ memoryview_tolist_impl(PyMemoryViewObject *self)
if (fmt == NULL)
return NULL;
if (view->ndim == 0) {
return unpack_single(view->buf, fmt);
return unpack_single(self, view->buf, fmt);
}
else if (view->ndim == 1) {
return tolist_base(view->buf, view->shape,
return tolist_base(self, view->buf, view->shape,
view->strides, view->suboffsets,
fmt);
}
else {
return tolist_rec(view->buf, view->ndim, view->shape,
return tolist_rec(self, view->buf, view->ndim, view->shape,
view->strides, view->suboffsets,
fmt);
}
Expand Down Expand Up @@ -2355,7 +2359,7 @@ memory_item(PyMemoryViewObject *self, Py_ssize_t index)
char *ptr = ptr_from_index(view, index);
if (ptr == NULL)
return NULL;
return unpack_single(ptr, fmt);
return unpack_single(self, ptr, fmt);
}

PyErr_SetString(PyExc_NotImplementedError,
Expand Down Expand Up @@ -2386,7 +2390,7 @@ memory_item_multi(PyMemoryViewObject *self, PyObject *tup)
ptr = ptr_from_tuple(view, tup);
if (ptr == NULL)
return NULL;
return unpack_single(ptr, fmt);
return unpack_single(self, ptr, fmt);
}

static inline int
Expand Down Expand Up @@ -2473,7 +2477,7 @@ memory_subscript(PyMemoryViewObject *self, PyObject *key)
const char *fmt = adjust_fmt(view);
if (fmt == NULL)
return NULL;
return unpack_single(view->buf, fmt);
return unpack_single(self, view->buf, fmt);
}
else if (key == Py_Ellipsis) {
Py_INCREF(self);
Expand Down Expand Up @@ -2567,7 +2571,6 @@ memory_ass_sub(PyMemoryViewObject *self, PyObject *key, PyObject *value)
index = PyNumber_AsSsize_t(key, PyExc_IndexError);
if (index == -1 && PyErr_Occurred())
return -1;
CHECK_RELEASED_INT(self); /* See gh-92888 for why we need this here */
ptr = ptr_from_index(view, index);
if (ptr == NULL)
return -1;
Expand Down Expand Up @@ -3211,7 +3214,7 @@ memoryiter_next(memoryiterobject *it)
if (ptr == NULL) {
return NULL;
}
return unpack_single(ptr, it->it_fmt);
return unpack_single(seq, ptr, it->it_fmt);
}

it->it_seq = NULL;
Expand Down