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bpo-34395: Fix memory leaks caused by incautious usage of PyMem_Resize(). #8756

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Merged
merged 2 commits into from
Aug 16, 2018
Merged

bpo-34395: Fix memory leaks caused by incautious usage of PyMem_Resize(). #8756

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c2bb8a6
bpo-34395: Fix memory leaks caused by incautious usage of PyMem_Resiz…
sir-sigurd Aug 13, 2018
60ea005
Restored some old behavior.
sir-sigurd Aug 14, 2018
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51 changes: 15 additions & 36 deletions Modules/_csv.c
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Original file line number Diff line number Diff line change
Expand Up @@ -555,25 +555,17 @@ parse_save_field(ReaderObj *self)
static int
parse_grow_buff(ReaderObj *self)
{
if (self->field_size == 0) {
self->field_size = 4096;
if (self->field != NULL)
PyMem_Free(self->field);
self->field = PyMem_New(Py_UCS4, self->field_size);
}
else {
Py_UCS4 *field = self->field;
if (self->field_size > PY_SSIZE_T_MAX / 2) {
PyErr_NoMemory();
return 0;
}
self->field_size *= 2;
self->field = PyMem_Resize(field, Py_UCS4, self->field_size);
}
if (self->field == NULL) {
assert((size_t)self->field_size <= PY_SSIZE_T_MAX / sizeof(Py_UCS4));

Py_ssize_t field_size_new = self->field_size ? 2 * self->field_size : 4096;
Py_UCS4 *field_new = self->field;
PyMem_Resize(field_new, Py_UCS4, field_size_new);
if (field_new == NULL) {
PyErr_NoMemory();
return 0;
}
self->field = field_new;
self->field_size = field_size_new;
return 1;
}

Expand Down Expand Up @@ -1089,31 +1081,18 @@ join_append_data(WriterObj *self, unsigned int field_kind, void *field_data,
static int
join_check_rec_size(WriterObj *self, Py_ssize_t rec_len)
{

if (rec_len < 0 || rec_len > PY_SSIZE_T_MAX - MEM_INCR) {
PyErr_NoMemory();
return 0;
}
assert(rec_len >= 0);

if (rec_len > self->rec_size) {
if (self->rec_size == 0) {
self->rec_size = (rec_len / MEM_INCR + 1) * MEM_INCR;
if (self->rec != NULL)
PyMem_Free(self->rec);
self->rec = PyMem_New(Py_UCS4, self->rec_size);
}
else {
Py_UCS4* old_rec = self->rec;

self->rec_size = (rec_len / MEM_INCR + 1) * MEM_INCR;
self->rec = PyMem_Resize(old_rec, Py_UCS4, self->rec_size);
if (self->rec == NULL)
PyMem_Free(old_rec);
}
if (self->rec == NULL) {
size_t rec_size_new = (size_t)(rec_len / MEM_INCR + 1) * MEM_INCR;
Py_UCS4 *rec_new = self->rec;
PyMem_Resize(rec_new, Py_UCS4, rec_size_new);
if (rec_new == NULL) {
PyErr_NoMemory();
return 0;
}
self->rec = rec_new;
self->rec_size = (Py_ssize_t)rec_size_new;
}
return 1;
}
Expand Down
13 changes: 7 additions & 6 deletions Modules/_pickle.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1382,11 +1382,13 @@ _Unpickler_ResizeMemoList(UnpicklerObject *self, Py_ssize_t new_size)

assert(new_size > self->memo_size);

PyMem_RESIZE(self->memo, PyObject *, new_size);
if (self->memo == NULL) {
PyObject **memo_new = self->memo;
PyMem_RESIZE(memo_new, PyObject *, new_size);
if (memo_new == NULL) {
PyErr_NoMemory();
return -1;
}
self->memo = memo_new;
for (i = self->memo_size; i < new_size; i++)
self->memo[i] = NULL;
self->memo_size = new_size;
Expand Down Expand Up @@ -6295,11 +6297,10 @@ load_mark(UnpicklerObject *self)
return -1;
}

if (self->marks == NULL)
self->marks = PyMem_NEW(Py_ssize_t, alloc);
else
PyMem_RESIZE(self->marks, Py_ssize_t, alloc);
Py_ssize_t *marks_old = self->marks;
PyMem_RESIZE(self->marks, Py_ssize_t, alloc);
if (self->marks == NULL) {
PyMem_FREE(marks_old);
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@sir-sigurd sir-sigurd Aug 16, 2018

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@serhiy-storchaka
Might make sense to not change self->marks at all instead of PyMem_FREE() when PyMem_RESIZE() fails?
It was implemented this way in 2.7:

cpython/Modules/cPickle.c

Lines 4661 to 4669 in 00aebab

if (self->marks == NULL)
marks=(Py_ssize_t *)malloc(s * sizeof(Py_ssize_t));
else
marks=(Py_ssize_t *)realloc(self->marks,
s * sizeof(Py_ssize_t));
if (!marks) {
PyErr_NoMemory();
return -1;
}

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@serhiy-storchaka serhiy-storchaka Aug 16, 2018

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Agree, it makes sense.

self->marks_size = 0;
PyErr_NoMemory();
return -1;
Expand Down