Hello,

I would like to report two heap corruption issue.

Test environment:
python ersion: python 2.7.11+ 
hg id: d858eadf2602 (2.7)
compile: clang with ASAN
OS: ubuntu x86_64

One is heap-buffer-overflow, the other is heap-user-after-free. 
All of samples are attached in this bug report.

Thanks,
-- Alex

In detail,

1) heap-buffer-overflow bug could be triggerd at cpython/Python/ceval.c:1229
ASAN report is following:

=================================================================
==26786==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x7ffff7ec56e8 at pc 0x5ec87f bp 0x7fffffffd2d0 sp 0x7fffffffd2c8
READ of size 8 at 0x7ffff7ec56e8 thread T0
    #0 0x5ec87e in PyEval_EvalFrameEx /project/cpython/Python/ceval.c:1229
    #1 0x5d3c6c in PyEval_EvalCodeEx /project/cpython/Python/ceval.c:3582
    #2 0x5d2b11 in PyEval_EvalCode /project/cpython/Python/ceval.c:669
    #3 0x6612d9 in run_pyc_file /project/cpython/Python/pythonrun.c:1406
    #4 0x6612d9 in PyRun_SimpleFileExFlags /project/cpython/Python/pythonrun.c:946
    #5 0x48e3dc in Py_Main /project/cpython/Modules/main.c:640
    #6 0x7ffff6ce282f in __libc_start_main /build/glibc-GKVZIf/glibc-2.23/csu/../csu/libc-start.c:291
    #7 0x48c518 in _start (/project/cpython/python.asan+0x48c518)

0x7ffff7ec56e8 is located 280 bytes to the left of 196608-byte region [0x7ffff7ec5800,0x7ffff7ef5800)
allocated by thread T0 here:
    #0 0x476429 in __interceptor_malloc /project/clang-3.4/llvm-3.4/projects/compiler-rt/lib/asan/asan_malloc_linux.cc:74
    #1 0x50e969 in dictresize /project/cpython/Objects/dictobject.c:643
    #2 0x537844 in PyString_InternInPlace /project/cpython/Objects/stringobject.c:4757

SUMMARY: AddressSanitizer: heap-buffer-overflow /project/cpython/Python/ceval.c:1229 PyEval_EvalFrameEx
Shadow bytes around the buggy address:
  0x10007efd0a80: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x10007efd0a90: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x10007efd0aa0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x10007efd0ab0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x10007efd0ac0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
=>0x10007efd0ad0: fa fa fa fa fa fa fa fa fa fa fa fa fa[fa]fa fa
  0x10007efd0ae0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x10007efd0af0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x10007efd0b00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x10007efd0b10: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x10007efd0b20: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
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
  ASan internal:         fe
==26786==ABORTING

2) heap-user-after-free bug could be triggerd at cpython/Objects/dictobject.c:732
ASAN report is following:

=================================================================
==26918==ERROR: AddressSanitizer: heap-use-after-free on address 0x60f00000ef98 at pc 0x50f5ac bp 0x7fffffffa1d0 sp 0x7fffffffa1c8
READ of size 8 at 0x60f00000ef98 thread T0
    #0 0x50f5ab in PyDict_GetItem /project/cpython/Objects/dictobject.c:732
    #1 0x537792 in PyString_InternInPlace /project/cpython/Objects/stringobject.c:4750
    #2 0x64fad5 in r_object /project/cpython/Python/marshal.c:822
    #3 0x650d00 in r_object /project/cpython/Python/marshal.c:1037
    #4 0x64edf6 in r_object /project/cpython/Python/marshal.c:886
    #5 0x650c1b in r_object /project/cpython/Python/marshal.c:1019
    #6 0x64e1b1 in PyMarshal_ReadObjectFromString /project/cpython/Python/marshal.c:1183
    #7 0x64e1b1 in PyMarshal_ReadLastObjectFromFile /project/cpython/Python/marshal.c:1144
    #8 0x6429c1 in read_compiled_module /project/cpython/Python/import.c:823
    #9 0x6429c1 in load_source_module /project/cpython/Python/import.c:1094
    #10 0x644cda in import_submodule /project/cpython/Python/import.c:2722
    #11 0x643e81 in load_next /project/cpython/Python/import.c:2537
    #12 0x63e061 in import_module_level /project/cpython/Python/import.c:2254
    #13 0x63e061 in PyImport_ImportModuleLevel /project/cpython/Python/import.c:2310
    #14 0x5c4e1a in builtin___import__ /project/cpython/Python/bltinmodule.c:49
    #15 0x5e2535 in do_call /project/cpython/Python/ceval.c:4564
    #16 0x5e2535 in call_function /project/cpython/Python/ceval.c:4372
    #17 0x5e2535 in PyEval_EvalFrameEx /project/cpython/Python/ceval.c:2987
    #18 0x5d3c6c in PyEval_EvalCodeEx /project/cpython/Python/ceval.c:3582
    #19 0x7237f3 in function_call /project/cpython/Objects/funcobject.c:523
    #20 0x4aca9a in PyObject_Call /project/cpython/Objects/abstract.c:2546
    #21 0x5f1313 in PyEval_CallObjectWithKeywords /project/cpython/Python/ceval.c:4219
    #22 0x62118c in _PyCodec_Lookup /project/cpython/Python/codecs.c:147
    #23 0x6227d5 in _PyCodec_LookupTextEncoding /project/cpython/Python/codecs.c:459
    #24 0x622b6a in codec_getitem_checked /project/cpython/Python/codecs.c:511
    #25 0x622b6a in _PyCodec_TextEncoder /project/cpython/Python/codecs.c:523
    #26 0x622b6a in _PyCodec_EncodeText /project/cpython/Python/codecs.c:537
    #27 0x54dbc8 in PyString_AsEncodedObject /project/cpython/Objects/stringobject.c:532
    #28 0x54dbc8 in string_encode /project/cpython/Objects/stringobject.c:3016
    #29 0x5e232f in call_function /project/cpython/Python/ceval.c:4350
    #30 0x5e232f in PyEval_EvalFrameEx /project/cpython/Python/ceval.c:2987
    #31 0x5d3c6c in PyEval_EvalCodeEx /project/cpython/Python/ceval.c:3582
    #32 0x5f2c7d in fast_function /project/cpython/Python/ceval.c:4445
    #33 0x5dd2ba in call_function /project/cpython/Python/ceval.c:4370
    #34 0x5dd2ba in PyEval_EvalFrameEx /project/cpython/Python/ceval.c:2987
    #35 0x5d3c6c in PyEval_EvalCodeEx /project/cpython/Python/ceval.c:3582
    #36 0x5d2b11 in PyEval_EvalCode /project/cpython/Python/ceval.c:669
    #37 0x6612d9 in run_pyc_file /project/cpython/Python/pythonrun.c:1406
    #38 0x6612d9 in PyRun_SimpleFileExFlags /project/cpython/Python/pythonrun.c:946
    #39 0x48e3dc in Py_Main /project/cpython/Modules/main.c:640
    #40 0x7ffff6ce282f in __libc_start_main /build/glibc-GKVZIf/glibc-2.23/csu/../csu/libc-start.c:291
    #41 0x48c518 in _start (/project/cpython/python.asan+0x48c518)

0x60f00000ef98 is located 72 bytes inside of 168-byte region [0x60f00000ef50,0x60f00000eff8)
freed by thread T0 here:
    #0 0x4762a9 in free /project/clang-3.4/llvm-3.4/projects/compiler-rt/lib/asan/asan_malloc_linux.cc:64
    #1 0x64fad5 in r_object /project/cpython/Python/marshal.c:822
    #2 0x64edf6 in r_object /project/cpython/Python/marshal.c:886
    #3 0x650c7a in r_object /project/cpython/Python/marshal.c:1022
    #4 0x64edf6 in r_object /project/cpython/Python/marshal.c:886
    #5 0x650c1b in r_object /project/cpython/Python/marshal.c:1019
    #6 0x64e1b1 in PyMarshal_ReadObjectFromString /project/cpython/Python/marshal.c:1183
    #7 0x64e1b1 in PyMarshal_ReadLastObjectFromFile /project/cpython/Python/marshal.c:1144
    #8 0x6429c1 in read_compiled_module /project/cpython/Python/import.c:823
    #9 0x6429c1 in load_source_module /project/cpython/Python/import.c:1094
    #10 0x644cda in import_submodule /project/cpython/Python/import.c:2722
    #11 0x643e81 in load_next /project/cpython/Python/import.c:2537

previously allocated by thread T0 here:
    #0 0x476429 in __interceptor_malloc /project/clang-3.4/llvm-3.4/projects/compiler-rt/lib/asan/asan_malloc_linux.cc:74
    #1 0x65de92 in new_threadstate /project/cpython/Python/pystate.c:159

SUMMARY: AddressSanitizer: heap-use-after-free /project/cpython/Objects/dictobject.c:732 PyDict_GetItem
Shadow bytes around the buggy address:
  0x0c1e7fff9da0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c1e7fff9db0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c1e7fff9dc0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c1e7fff9dd0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c1e7fff9de0: fa fa fa fa fa fa fa fa fa fa fd fd fd fd fd fd
=>0x0c1e7fff9df0: fd fd fd[fd]fd fd fd fd fd fd fd fd fd fd fd fa
  0x0c1e7fff9e00: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c1e7fff9e10: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c1e7fff9e20: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c1e7fff9e30: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c1e7fff9e40: fa fa fa fa fa fa fa fa fa fa fa 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
  ASan internal:         fe
==26918==ABORTING
QUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFB
QUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFB
QUFBQUFBQUFBQUFBQUE=