295 lines
8.6 KiB
Python
295 lines
8.6 KiB
Python
![]() |
# for Jython's use of CHM, removed pathological case of
|
||
|
# machiavelli. this may or may not legal without some locking in the
|
||
|
# underlying java code, in any event, it's not so interesting right
|
||
|
# now
|
||
|
|
||
|
from test.test_support import verbose, TESTFN
|
||
|
import random
|
||
|
import os
|
||
|
|
||
|
# From SF bug #422121: Insecurities in dict comparison.
|
||
|
|
||
|
# Safety of code doing comparisons has been an historical Python weak spot.
|
||
|
# The problem is that comparison of structures written in C *naturally*
|
||
|
# wants to hold on to things like the size of the container, or "the
|
||
|
# biggest" containee so far, across a traversal of the container; but
|
||
|
# code to do containee comparisons can call back into Python and mutate
|
||
|
# the container in arbitrary ways while the C loop is in midstream. If the
|
||
|
# C code isn't extremely paranoid about digging things out of memory on
|
||
|
# each trip, and artificially boosting refcounts for the duration, anything
|
||
|
# from infinite loops to OS crashes can result (yes, I use Windows <wink>).
|
||
|
#
|
||
|
# The other problem is that code designed to provoke a weakness is usually
|
||
|
# white-box code, and so catches only the particular vulnerabilities the
|
||
|
# author knew to protect against. For example, Python's list.sort() code
|
||
|
# went thru many iterations as one "new" vulnerability after another was
|
||
|
# discovered.
|
||
|
#
|
||
|
# So the dict comparison test here uses a black-box approach instead,
|
||
|
# generating dicts of various sizes at random, and performing random
|
||
|
# mutations on them at random times. This proved very effective,
|
||
|
# triggering at least six distinct failure modes the first 20 times I
|
||
|
# ran it. Indeed, at the start, the driver never got beyond 6 iterations
|
||
|
# before the test died.
|
||
|
|
||
|
# The dicts are global to make it easy to mutate tham from within functions.
|
||
|
dict1 = {}
|
||
|
dict2 = {}
|
||
|
|
||
|
# The current set of keys in dict1 and dict2. These are materialized as
|
||
|
# lists to make it easy to pick a dict key at random.
|
||
|
dict1keys = []
|
||
|
dict2keys = []
|
||
|
|
||
|
# Global flag telling maybe_mutate() wether to *consider* mutating.
|
||
|
mutate = 0
|
||
|
|
||
|
# If global mutate is true, consider mutating a dict. May or may not
|
||
|
# mutate a dict even if mutate is true. If it does decide to mutate a
|
||
|
# dict, it picks one of {dict1, dict2} at random, and deletes a random
|
||
|
# entry from it; or, more rarely, adds a random element.
|
||
|
|
||
|
def maybe_mutate():
|
||
|
global mutate
|
||
|
if not mutate:
|
||
|
return
|
||
|
if random.random() < 0.5:
|
||
|
return
|
||
|
|
||
|
if random.random() < 0.5:
|
||
|
target, keys = dict1, dict1keys
|
||
|
else:
|
||
|
target, keys = dict2, dict2keys
|
||
|
|
||
|
if random.random() < 0.2:
|
||
|
# Insert a new key.
|
||
|
mutate = 0 # disable mutation until key inserted
|
||
|
while 1:
|
||
|
newkey = Horrid(random.randrange(100))
|
||
|
if newkey not in target:
|
||
|
break
|
||
|
target[newkey] = Horrid(random.randrange(100))
|
||
|
keys.append(newkey)
|
||
|
mutate = 1
|
||
|
|
||
|
elif keys:
|
||
|
# Delete a key at random.
|
||
|
i = random.randrange(len(keys))
|
||
|
key = keys[i]
|
||
|
del target[key]
|
||
|
# CAUTION: don't use keys.remove(key) here. Or do <wink>. The
|
||
|
# point is that .remove() would trigger more comparisons, and so
|
||
|
# also more calls to this routine. We're mutating often enough
|
||
|
# without that.
|
||
|
del keys[i]
|
||
|
|
||
|
# A horrid class that triggers random mutations of dict1 and dict2 when
|
||
|
# instances are compared.
|
||
|
|
||
|
class Horrid:
|
||
|
def __init__(self, i):
|
||
|
# Comparison outcomes are determined by the value of i.
|
||
|
self.i = i
|
||
|
|
||
|
# An artificial hashcode is selected at random so that we don't
|
||
|
# have any systematic relationship between comparison outcomes
|
||
|
# (based on self.i and other.i) and relative position within the
|
||
|
# hash vector (based on hashcode).
|
||
|
self.hashcode = random.randrange(1000000000)
|
||
|
|
||
|
def __hash__(self):
|
||
|
return self.hashcode
|
||
|
|
||
|
def __cmp__(self, other):
|
||
|
maybe_mutate() # The point of the test.
|
||
|
return cmp(self.i, other.i)
|
||
|
|
||
|
def __repr__(self):
|
||
|
return "Horrid(%d)" % self.i
|
||
|
|
||
|
# Fill dict d with numentries (Horrid(i), Horrid(j)) key-value pairs,
|
||
|
# where i and j are selected at random from the candidates list.
|
||
|
# Return d.keys() after filling.
|
||
|
|
||
|
def fill_dict(d, candidates, numentries):
|
||
|
d.clear()
|
||
|
for i in xrange(numentries):
|
||
|
d[Horrid(random.choice(candidates))] = \
|
||
|
Horrid(random.choice(candidates))
|
||
|
return d.keys()
|
||
|
|
||
|
# Test one pair of randomly generated dicts, each with n entries.
|
||
|
# Note that dict comparison is trivial if they don't have the same number
|
||
|
# of entires (then the "shorter" dict is instantly considered to be the
|
||
|
# smaller one, without even looking at the entries).
|
||
|
|
||
|
def test_one(n):
|
||
|
global mutate, dict1, dict2, dict1keys, dict2keys
|
||
|
|
||
|
# Fill the dicts without mutating them.
|
||
|
mutate = 0
|
||
|
dict1keys = fill_dict(dict1, range(n), n)
|
||
|
dict2keys = fill_dict(dict2, range(n), n)
|
||
|
|
||
|
# Enable mutation, then compare the dicts so long as they have the
|
||
|
# same size.
|
||
|
mutate = 1
|
||
|
if verbose:
|
||
|
print "trying w/ lengths", len(dict1), len(dict2),
|
||
|
while dict1 and len(dict1) == len(dict2):
|
||
|
if verbose:
|
||
|
print ".",
|
||
|
c = cmp(dict1, dict2)
|
||
|
if verbose:
|
||
|
print
|
||
|
|
||
|
# Run test_one n times. At the start (before the bugs were fixed), 20
|
||
|
# consecutive runs of this test each blew up on or before the sixth time
|
||
|
# test_one was run. So n doesn't have to be large to get an interesting
|
||
|
# test.
|
||
|
# OTOH, calling with large n is also interesting, to ensure that the fixed
|
||
|
# code doesn't hold on to refcounts *too* long (in which case memory would
|
||
|
# leak).
|
||
|
|
||
|
def test(n):
|
||
|
for i in xrange(n):
|
||
|
test_one(random.randrange(1, 100))
|
||
|
|
||
|
# See last comment block for clues about good values for n.
|
||
|
test(100)
|
||
|
|
||
|
##########################################################################
|
||
|
# Another segfault bug, distilled by Michael Hudson from a c.l.py post.
|
||
|
|
||
|
class Child:
|
||
|
def __init__(self, parent):
|
||
|
self.__dict__['parent'] = parent
|
||
|
def __getattr__(self, attr):
|
||
|
self.parent.a = 1
|
||
|
self.parent.b = 1
|
||
|
self.parent.c = 1
|
||
|
self.parent.d = 1
|
||
|
self.parent.e = 1
|
||
|
self.parent.f = 1
|
||
|
self.parent.g = 1
|
||
|
self.parent.h = 1
|
||
|
self.parent.i = 1
|
||
|
return getattr(self.parent, attr)
|
||
|
|
||
|
class Parent:
|
||
|
def __init__(self):
|
||
|
self.a = Child(self)
|
||
|
|
||
|
# Hard to say what this will print! May vary from time to time. But
|
||
|
# we're specifically trying to test the tp_print slot here, and this is
|
||
|
# the clearest way to do it. We print the result to a temp file so that
|
||
|
# the expected-output file doesn't need to change.
|
||
|
|
||
|
f = open(TESTFN, "w")
|
||
|
print >> f, Parent().__dict__
|
||
|
f.close()
|
||
|
os.unlink(TESTFN)
|
||
|
|
||
|
##########################################################################
|
||
|
# And another core-dumper from Michael Hudson.
|
||
|
|
||
|
dict = {}
|
||
|
|
||
|
# Force dict to malloc its table.
|
||
|
for i in range(1, 10):
|
||
|
dict[i] = i
|
||
|
|
||
|
f = open(TESTFN, "w")
|
||
|
|
||
|
class Machiavelli:
|
||
|
def __repr__(self):
|
||
|
dict.clear()
|
||
|
|
||
|
# Michael sez: "doesn't crash without this. don't know why."
|
||
|
# Tim sez: "luck of the draw; crashes with or without for me."
|
||
|
print >> f
|
||
|
|
||
|
return `"machiavelli"`
|
||
|
|
||
|
def __hash__(self):
|
||
|
return 0
|
||
|
|
||
|
# zyasoft - this currently crashes with CHM implementation of dict;
|
||
|
# need to figure out why this is the case, but it does looks quite
|
||
|
# evil, doesn't it?
|
||
|
|
||
|
#dict[Machiavelli()] = Machiavelli()
|
||
|
|
||
|
print >> f, str(dict)
|
||
|
f.close()
|
||
|
os.unlink(TESTFN)
|
||
|
del f, dict
|
||
|
|
||
|
|
||
|
##########################################################################
|
||
|
# And another core-dumper from Michael Hudson.
|
||
|
|
||
|
dict = {}
|
||
|
|
||
|
# let's force dict to malloc its table
|
||
|
for i in range(1, 10):
|
||
|
dict[i] = i
|
||
|
|
||
|
class Machiavelli2:
|
||
|
def __eq__(self, other):
|
||
|
dict.clear()
|
||
|
return 1
|
||
|
|
||
|
def __hash__(self):
|
||
|
return 0
|
||
|
|
||
|
dict[Machiavelli2()] = Machiavelli2()
|
||
|
|
||
|
try:
|
||
|
dict[Machiavelli2()]
|
||
|
except KeyError:
|
||
|
pass
|
||
|
|
||
|
del dict
|
||
|
|
||
|
##########################################################################
|
||
|
# And another core-dumper from Michael Hudson.
|
||
|
|
||
|
dict = {}
|
||
|
|
||
|
# let's force dict to malloc its table
|
||
|
for i in range(1, 10):
|
||
|
dict[i] = i
|
||
|
|
||
|
class Machiavelli3:
|
||
|
def __init__(self, id):
|
||
|
self.id = id
|
||
|
|
||
|
def __eq__(self, other):
|
||
|
if self.id == other.id:
|
||
|
dict.clear()
|
||
|
return 1
|
||
|
else:
|
||
|
return 0
|
||
|
|
||
|
def __repr__(self):
|
||
|
return "%s(%s)"%(self.__class__.__name__, self.id)
|
||
|
|
||
|
def __hash__(self):
|
||
|
return 0
|
||
|
|
||
|
dict[Machiavelli3(1)] = Machiavelli3(0)
|
||
|
dict[Machiavelli3(2)] = Machiavelli3(0)
|
||
|
|
||
|
f = open(TESTFN, "w")
|
||
|
try:
|
||
|
try:
|
||
|
print >> f, dict[Machiavelli3(2)]
|
||
|
except KeyError:
|
||
|
pass
|
||
|
finally:
|
||
|
f.close()
|
||
|
os.unlink(TESTFN)
|
||
|
|
||
|
del dict
|