New submission from Dk0n9 <[email protected]>:
The variable `heap` in heappushpop does not add a reference count
```c
cmp = PyObject_RichCompareBool(PyList_GET_ITEM(heap, 0), item, Py_LT);
if (cmp < 0)
return NULL;
if (cmp == 0) {
Py_INCREF(item);
return item;
}
```
POC：
```python
import heapq
class h(int):
def __lt__(self, o):
list1.clear()
return NotImplemented
list1 = []
heapq.heappush(list1, h(0))
heapq.heappushpop(list1, 1)
```
Crash detail with asan:
==62141==ERROR: AddressSanitizer: heap-use-after-free on address 0x6060000fd778
at pc 0x00000049cdce bp 0x7ffe9690f650 sp 0x7ffe9690f640
READ of size 8 at 0x6060000fd778 thread T0
#0 0x49cdcd in long_richcompare Objects/longobject.c:3047
#1 0x4f9495 in do_richcompare Objects/object.c:802
#2 0x4f9495 in PyObject_RichCompare Objects/object.c:846
#3 0x4f9495 in PyObject_RichCompareBool Objects/object.c:868
#4 0x7ff74c523594 in _heapq_heappushpop_impl
/home/******/Python-3.9.0a2/Modules/_heapqmodule.c:267
#5 0x7ff74c523594 in _heapq_heappushpop
/home/******/Python-3.9.0a2/Modules/clinic/_heapqmodule.c.h:109
#6 0x854c30 in cfunction_vectorcall_FASTCALL Objects/methodobject.c:366
#7 0x443885 in _PyObject_VectorcallTstate Include/cpython/abstract.h:111
#8 0x443885 in _PyObject_Vectorcall Include/cpython/abstract.h:120
#9 0x443885 in call_function Python/ceval.c:4850
#10 0x443885 in _PyEval_EvalFrameDefault Python/ceval.c:3306
#11 0x5e1d76 in _PyEval_EvalFrame Include/internal/pycore_ceval.h:43
#12 0x5e1d76 in _PyEval_EvalCode Python/ceval.c:4142
#13 0x5e2207 in _PyEval_EvalCodeWithName Python/ceval.c:4174
#14 0x5e2207 in PyEval_EvalCodeEx Python/ceval.c:4190
#15 0x5e2207 in PyEval_EvalCode Python/ceval.c:717
#16 0x6862fc in run_eval_code_obj Python/pythonrun.c:1125
#17 0x6862fc in run_mod Python/pythonrun.c:1147
#18 0x6862fc in PyRun_FileExFlags Python/pythonrun.c:1063
#19 0x6867b2 in PyRun_SimpleFileExFlags Python/pythonrun.c:428
#20 0x446495 in pymain_run_file Modules/main.c:369
#21 0x446495 in pymain_run_python Modules/main.c:553
#22 0x446495 in Py_RunMain Modules/main.c:632
#23 0x446f86 in pymain_main Modules/main.c:662
#24 0x446f86 in Py_BytesMain Modules/main.c:686
#25 0x7ff74f34882f in __libc_start_main
(/lib/x86_64-linux-gnu/libc.so.6+0x2082f)
#26 0x444478 in _start (/home/***/Python-3.9.0a2/python+0x444478)
0x6060000fd778 is located 24 bytes inside of 56-byte region
[0x6060000fd760,0x6060000fd798)
freed by thread T0 here:
#0 0x7ff7500b72ca in __interceptor_free
(/usr/lib/x86_64-linux-gnu/libasan.so.2+0x982ca)
#1 0x52a5d9 in subtype_dealloc Objects/typeobject.c:1291
#2 0x4222a6 in _Py_DECREF Include/object.h:478
#3 0x4222a6 in frame_dealloc Objects/frameobject.c:636
#4 0x422088 in _Py_DECREF Include/object.h:478
#5 0x422088 in function_code_fastcall Objects/call.c:335
#6 0x53aac6 in _PyObject_VectorcallTstate Include/cpython/abstract.h:111
#7 0x53aac6 in vectorcall_unbound Objects/typeobject.c:1459
#8 0x53aac6 in slot_tp_richcompare Objects/typeobject.c:6703
#9 0x4f921d in do_richcompare Objects/object.c:796
#10 0x4f921d in PyObject_RichCompare Objects/object.c:846
#11 0x4f921d in PyObject_RichCompareBool Objects/object.c:868
#12 0x7ff74c523594 in _heapq_heappushpop_impl
/home/******/Python-3.9.0a2/Modules/_heapqmodule.c:267
#13 0x7ff74c523594 in _heapq_heappushpop
/home/******/Python-3.9.0a2/Modules/clinic/_heapqmodule.c.h:109
#14 0x854c30 in cfunction_vectorcall_FASTCALL Objects/methodobject.c:366
#15 0x443885 in _PyObject_VectorcallTstate Include/cpython/abstract.h:111
#16 0x443885 in _PyObject_Vectorcall Include/cpython/abstract.h:120
#17 0x443885 in call_function Python/ceval.c:4850
#18 0x443885 in _PyEval_EvalFrameDefault Python/ceval.c:3306
#19 0x5e1d76 in _PyEval_EvalFrame Include/internal/pycore_ceval.h:43
#20 0x5e1d76 in _PyEval_EvalCode Python/ceval.c:4142
#21 0x5e2207 in _PyEval_EvalCodeWithName Python/ceval.c:4174
#22 0x5e2207 in PyEval_EvalCodeEx Python/ceval.c:4190
#23 0x5e2207 in PyEval_EvalCode Python/ceval.c:717
#24 0x6862fc in run_eval_code_obj Python/pythonrun.c:1125
#25 0x6862fc in run_mod Python/pythonrun.c:1147
#26 0x6862fc in PyRun_FileExFlags Python/pythonrun.c:1063
#27 0x6867b2 in PyRun_SimpleFileExFlags Python/pythonrun.c:428
#28 0x446495 in pymain_run_file Modules/main.c:369
#29 0x446495 in pymain_run_python Modules/main.c:553
#30 0x446495 in Py_RunMain Modules/main.c:632
#31 0x446f86 in pymain_main Modules/main.c:662
#32 0x446f86 in Py_BytesMain Modules/main.c:686
#33 0x7ff74f34882f in __libc_start_main
(/lib/x86_64-linux-gnu/libc.so.6+0x2082f)
previously allocated by thread T0 here:
#0 0x7ff7500b7602 in malloc (/usr/lib/x86_64-linux-gnu/libasan.so.2+0x98602)
#1 0x6dbfd5 in _PyObject_GC_Alloc Modules/gcmodule.c:2146
#2 0x6dbfd5 in _PyObject_GC_Malloc Modules/gcmodule.c:2173
#3 0x527d20 in PyType_GenericAlloc Objects/typeobject.c:1014
#4 0x4b890b in long_subtype_new Objects/longobject.c:5132
#5 0x4b890b in long_new_impl Objects/longobject.c:5075
#6 0x4b890b in long_new Objects/clinic/longobject.c.h:36
#7 0x52f606 in type_call Objects/typeobject.c:973
#8 0x462b46 in _PyObject_MakeTpCall Objects/call.c:189
#9 0x436b70 in _PyObject_VectorcallTstate Include/cpython/abstract.h:109
#10 0x436b70 in _PyObject_Vectorcall Include/cpython/abstract.h:120
#11 0x436b70 in call_function Python/ceval.c:4850
#12 0x436b70 in _PyEval_EvalFrameDefault Python/ceval.c:3337
#13 0x5e1d76 in _PyEval_EvalFrame Include/internal/pycore_ceval.h:43
#14 0x5e1d76 in _PyEval_EvalCode Python/ceval.c:4142
#15 0x5e2207 in _PyEval_EvalCodeWithName Python/ceval.c:4174
#16 0x5e2207 in PyEval_EvalCodeEx Python/ceval.c:4190
#17 0x5e2207 in PyEval_EvalCode Python/ceval.c:717
#18 0x6862fc in run_eval_code_obj Python/pythonrun.c:1125
#19 0x6862fc in run_mod Python/pythonrun.c:1147
#20 0x6862fc in PyRun_FileExFlags Python/pythonrun.c:1063
#21 0x6867b2 in PyRun_SimpleFileExFlags Python/pythonrun.c:428
#22 0x446495 in pymain_run_file Modules/main.c:369
#23 0x446495 in pymain_run_python Modules/main.c:553
#24 0x446495 in Py_RunMain Modules/main.c:632
#25 0x446f86 in pymain_main Modules/main.c:662
#26 0x446f86 in Py_BytesMain Modules/main.c:686
#27 0x7ff74f34882f in __libc_start_main
(/lib/x86_64-linux-gnu/libc.so.6+0x2082f)
SUMMARY: AddressSanitizer: heap-use-after-free Objects/longobject.c:3047
long_richcompare
Shadow bytes around the buggy address:
0x0c0c80017a90: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c0c80017aa0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c0c80017ab0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c0c80017ac0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c0c80017ad0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
=>0x0c0c80017ae0: fd fd fd fd fd fd fd fa fa fa fa fa fd fd fd[fd]
0x0c0c80017af0: fd fd fd fa fa fa fa fa fd fd fd fd fd fd fd fa
0x0c0c80017b00: fa fa fa fa fd fd fd fd fd fd fd fd fa fa fa fa
0x0c0c80017b10: 00 00 00 00 00 00 00 00 fa fa fa fa fd fd fd fd
0x0c0c80017b20: fd fd fd fa fa fa fa fa fd fd fd fd fd fd fd fa
0x0c0c80017b30: fa fa fa fa fd fd fd fd fd fd fd fa fa fa fa fa
Shadow byte legend (one shadow byte represents 8 application bytes):
Addressable: 00
Partially addressable: 01 02 03 04 05 06 07
Heap left redzone: fa
Heap right redzone: fb
Freed heap region: fd
Stack left redzone: f1
Stack mid redzone: f2
Stack right redzone: f3
Stack partial redzone: f4
Stack after return: f5
Stack use after scope: f8
Global redzone: f9
Global init order: f6
Poisoned by user: f7
Container overflow: fc
Array cookie: ac
Intra object redzone: bb
ASan internal: fe
==62141==ABORTING
----------
_______________________________________
Python tracker <[email protected]>
<https://bugs.python.org/issue39421>
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