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"""
There is a way to put keys of any type in a type's dictionary.
I think this allows various kinds of crashes, but so far I have only
found a convoluted attack of _PyType_Lookup(), which uses the mro of the
type without holding a strong reference to it. Probably works with
super.__getattribute__() too, which uses the same kind of code.
"""
class MyKey(object):
def __hash__(self):
return hash('mykey')
def __cmp__(self, other):
# the following line decrefs the previous X.__mro__
X.__bases__ = (Base2,)
# trash all tuples of length 3, to make sure that the items of
# the previous X.__mro__ are really garbage
z = []
for i in range(1000):
z.append((i, None, None))
return -1
class Base(object):
mykey = 'from Base'
class Base2(object):
mykey = 'from Base2'
class X(Base):
# you can't add a non-string key to X.__dict__, but it can be
# there from the beginning :-)
locals()[MyKey()] = 5
print X.mykey
# I get a segfault, or a slightly wrong assertion error in a debug build.
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