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bpo-23689: re module, fix memory leak when a match is terminated by a signal or memory allocation failure #32223

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d43cefe
1. add variables
wjssz Mar 31, 2022
f0d2621
2. add CompileData class to sre_compile.py
wjssz Mar 31, 2022
b8b9921
3. add repeat_count parameter to _sre.compile() function
wjssz Mar 31, 2022
17907f5
4. emit repeat_count in sre_compile.py
wjssz Mar 31, 2022
787ca6f
5. change _validate_outer() parameter
wjssz Mar 31, 2022
6ec932b
6. validate in _validate_inner()
wjssz Mar 31, 2022
01c4c29
7. allocate repeats_array for SRE_STATE
wjssz Mar 31, 2022
7631b7d
8. support code in sre_lib.h
wjssz Mar 31, 2022
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60 changes: 38 additions & 22 deletions Lib/sre_compile.py
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Original file line number Diff line number Diff line change
Expand Up @@ -67,14 +67,21 @@
_ignorecase_fixes = {i: tuple(j for j in t if i != j)
for t in _equivalences for i in t}

class CompileData:
__slots__ = ('code', 'repeat_count')
def __init__(self):
self.code = []
self.repeat_count = 0

def _combine_flags(flags, add_flags, del_flags,
TYPE_FLAGS=sre_parse.TYPE_FLAGS):
if add_flags & TYPE_FLAGS:
flags &= ~TYPE_FLAGS
return (flags | add_flags) & ~del_flags

def _compile(code, pattern, flags):
def _compile(data, pattern, flags):
# internal: compile a (sub)pattern
code = data.code
emit = code.append
_len = len
LITERAL_CODES = _LITERAL_CODES
Expand Down Expand Up @@ -147,15 +154,18 @@ def _compile(code, pattern, flags):
skip = _len(code); emit(0)
emit(av[0])
emit(av[1])
_compile(code, av[2], flags)
_compile(data, av[2], flags)
emit(SUCCESS)
code[skip] = _len(code) - skip
else:
emit(REPEATING_CODES[op][0])
skip = _len(code); emit(0)
emit(av[0])
emit(av[1])
_compile(code, av[2], flags)
if op != POSSESSIVE_REPEAT:
emit(data.repeat_count)
data.repeat_count += 1
_compile(data, av[2], flags)
code[skip] = _len(code) - skip
emit(REPEATING_CODES[op][1])
elif op is SUBPATTERN:
Expand All @@ -164,7 +174,7 @@ def _compile(code, pattern, flags):
emit(MARK)
emit((group-1)*2)
# _compile_info(code, p, _combine_flags(flags, add_flags, del_flags))
_compile(code, p, _combine_flags(flags, add_flags, del_flags))
_compile(data, p, _combine_flags(flags, add_flags, del_flags))
if group:
emit(MARK)
emit((group-1)*2+1)
Expand All @@ -176,7 +186,7 @@ def _compile(code, pattern, flags):
# pop their stack if they reach it
emit(ATOMIC_GROUP)
skip = _len(code); emit(0)
_compile(code, av, flags)
_compile(data, av, flags)
emit(SUCCESS)
code[skip] = _len(code) - skip
elif op in SUCCESS_CODES:
Expand All @@ -191,13 +201,13 @@ def _compile(code, pattern, flags):
if lo != hi:
raise error("look-behind requires fixed-width pattern")
emit(lo) # look behind
_compile(code, av[1], flags)
_compile(data, av[1], flags)
emit(SUCCESS)
code[skip] = _len(code) - skip
elif op is CALL:
emit(op)
skip = _len(code); emit(0)
_compile(code, av, flags)
_compile(data, av, flags)
emit(SUCCESS)
code[skip] = _len(code) - skip
elif op is AT:
Expand All @@ -216,7 +226,7 @@ def _compile(code, pattern, flags):
for av in av[1]:
skip = _len(code); emit(0)
# _compile_info(code, av, flags)
_compile(code, av, flags)
_compile(data, av, flags)
emit(JUMP)
tailappend(_len(code)); emit(0)
code[skip] = _len(code) - skip
Expand Down Expand Up @@ -244,12 +254,12 @@ def _compile(code, pattern, flags):
emit(op)
emit(av[0]-1)
skipyes = _len(code); emit(0)
_compile(code, av[1], flags)
_compile(data, av[1], flags)
if av[2]:
emit(JUMP)
skipno = _len(code); emit(0)
code[skipyes] = _len(code) - skipyes + 1
_compile(code, av[2], flags)
_compile(data, av[2], flags)
code[skipno] = _len(code) - skipno
else:
code[skipyes] = _len(code) - skipyes + 1
Expand Down Expand Up @@ -608,17 +618,17 @@ def isstring(obj):
def _code(p, flags):

flags = p.state.flags | flags
code = []
data = CompileData()

# compile info block
_compile_info(code, p, flags)
_compile_info(data.code, p, flags)

# compile the pattern
_compile(code, p.data, flags)
_compile(data, p.data, flags)

code.append(SUCCESS)
data.code.append(SUCCESS)

return code
return data

def _hex_code(code):
return '[%s]' % ', '.join('%#0*x' % (_sre.CODESIZE*2+2, x) for x in code)
Expand Down Expand Up @@ -719,14 +729,21 @@ def print_2(*args):
else:
print_(FAILURE)
i += 1
elif op in (REPEAT, REPEAT_ONE, MIN_REPEAT_ONE,
elif op in (REPEAT_ONE, MIN_REPEAT_ONE,
POSSESSIVE_REPEAT, POSSESSIVE_REPEAT_ONE):
skip, min, max = code[i: i+3]
if max == MAXREPEAT:
max = 'MAXREPEAT'
print_(op, skip, min, max, to=i+skip)
dis_(i+3, i+skip)
i += skip
elif op is REPEAT:
skip, min, max, repeat_count = code[i: i+4]
if max == MAXREPEAT:
max = 'MAXREPEAT'
print_(op, skip, min, max, repeat_count, to=i+skip)
dis_(i+4, i+skip)
i += skip
elif op is GROUPREF_EXISTS:
arg, skip = code[i: i+2]
print_(op, arg, skip, to=i+skip)
Expand Down Expand Up @@ -781,11 +798,11 @@ def compile(p, flags=0):
else:
pattern = None

code = _code(p, flags)
data = _code(p, flags)

if flags & SRE_FLAG_DEBUG:
print()
dis(code)
dis(data.code)

# map in either direction
groupindex = p.state.groupdict
Expand All @@ -794,7 +811,6 @@ def compile(p, flags=0):
indexgroup[i] = k

return _sre.compile(
pattern, flags | p.state.flags, code,
p.state.groups-1,
groupindex, tuple(indexgroup)
)
pattern, flags | p.state.flags, data.code,
p.state.groups-1, groupindex, tuple(indexgroup),
data.repeat_count)
2 changes: 1 addition & 1 deletion Lib/sre_constants.py
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Original file line number Diff line number Diff line change
Expand Up @@ -13,7 +13,7 @@

# update when constants are added or removed

MAGIC = 20220318
MAGIC = 20220331

from _sre import MAXREPEAT, MAXGROUPS

Expand Down
4 changes: 2 additions & 2 deletions Lib/test/test_re.py
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Expand Up @@ -1643,9 +1643,9 @@ def test_dealloc(self):
long_overflow = 2**128
self.assertRaises(TypeError, re.finditer, "a", {})
with self.assertRaises(OverflowError):
_sre.compile("abc", 0, [long_overflow], 0, {}, ())
_sre.compile("abc", 0, [long_overflow], 0, {}, (), 0)
with self.assertRaises(TypeError):
_sre.compile({}, 0, [], 0, [], [])
_sre.compile({}, 0, [], 0, [], [], 0)

def test_search_dot_unicode(self):
self.assertTrue(re.search("123.*-", '123abc-'))
Expand Down
2 changes: 2 additions & 0 deletions Misc/NEWS.d/next/Library/2022-03-31-21-08-41.bpo-23689.TFSc3E.rst
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Original file line number Diff line number Diff line change
@@ -0,0 +1,2 @@
:mod:`re` module: fix memory leak when a match is terminated by a signal or
memory allocation failure. Patch by Ma Lin.
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