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Code Issues Projects Releases Packages Wiki Activity Actions 9

GH-96569: Add two NULL checks to avoid undefined behavior. (GH-96585)

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Mark Shannon 2022-09-06 16:45:43 +01:00 • committed by GitHub
parent cd0ff9bd14
commit 222f10ca2d
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3 changed files with 13 additions and 10 deletions
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9
Include/internal/pycore_frame.h
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@ -190,11 +190,16 @@ _PyFrame_FastToLocalsWithError(_PyInterpreterFrame *frame);
void void
_PyFrame_LocalsToFast(_PyInterpreterFrame *frame, int clear); _PyFrame_LocalsToFast(_PyInterpreterFrame *frame, int clear);
static inline bool static inline bool
_PyThreadState_HasStackSpace(PyThreadState *tstate, int size) _PyThreadState_HasStackSpace(PyThreadState *tstate, int size)
{ {
return tstate->datastack_top + size < tstate->datastack_limit; assert(
(tstate->datastack_top == NULL && tstate->datastack_limit == NULL)
||
(tstate->datastack_top != NULL && tstate->datastack_limit != NULL)
);
return tstate->datastack_top != NULL &&
size < tstate->datastack_limit - tstate->datastack_top;
} }
extern _PyInterpreterFrame * extern _PyInterpreterFrame *

1
Misc/NEWS.d/next/Core and Builtins/2022-09-05-16-43-44.gh-issue-96569.9lmTCC.rst Normal file
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@ -0,0 +1 @@
Remove two cases of undefined behavoir, by adding NULL checks.

13
Python/pystate.c
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@ -2195,15 +2195,12 @@ _PyInterpreterFrame *
_PyThreadState_PushFrame(PyThreadState *tstate, size_t size) _PyThreadState_PushFrame(PyThreadState *tstate, size_t size)
{ {
assert(size < INT_MAX/sizeof(PyObject *)); assert(size < INT_MAX/sizeof(PyObject *));
PyObject **base = tstate->datastack_top; if (_PyThreadState_HasStackSpace(tstate, (int)size)) {
PyObject **top = base + size; _PyInterpreterFrame *res = (_PyInterpreterFrame *)tstate->datastack_top;
if (top >= tstate->datastack_limit) { tstate->datastack_top += size;
base = push_chunk(tstate, (int)size); return res;
} }
else { return (_PyInterpreterFrame *)push_chunk(tstate, (int)size);
tstate->datastack_top = top;
}
return (_PyInterpreterFrame *)base;
} }
void void