decouple hash generation from comment view and allow customization

Tests now use a dummy hash function that does nothing (basically) and
run a bit faster now.
pull/101/head
Martin Zimmermann 10 years ago
parent 91e63c7e5f
commit 9260e143f1

@ -261,6 +261,32 @@ allowed-attributes
To allow images in comments, you just need to add ``allowed-elements = img`` and
``allowed-attributes = src``.
Hash
----
Customize used hash functions to hide the actual email addresses from
commenters but still be able to generate an identicon.
.. code-block:: ini
[hash]
salt = Eech7co8Ohloopo9Ol6baimi
algorithm = pbkdf2
salt
A salt is used to protect against rainbow tables. Isso does not make use of
pepper (yet). The default value has been in use since the release of Isso
and generates the same identicons for same addresses across installations.
algorithm
Hash algorithm to use -- either from Python's `hashlib` or PBKDF2 (a
computational expensive hash function).
The actual identifier for PBKDF2 is `pbkdf2:1000:6:sha1`, which means 1000
iterations, 6 bytes to generate and SHA1 as pseudo-random family used for
key strengthening.
Arguments have to be in that order, but can be reduced to `pbkdf2:4096`
for example to override the iterations only.
Appendum
--------

@ -65,7 +65,7 @@ local_manager = LocalManager([local])
from isso import db, migrate, wsgi, ext, views
from isso.core import ThreadedMixin, ProcessMixin, uWSGIMixin, Config
from isso.wsgi import origin, urlsplit
from isso.utils import http, JSONRequest, html
from isso.utils import http, JSONRequest, html, hash
from isso.views import comments
from isso.ext.notifications import Stdout, SMTP
@ -80,14 +80,13 @@ logger = logging.getLogger("isso")
class Isso(object):
salt = b"Eech7co8Ohloopo9Ol6baimi"
def __init__(self, conf):
self.conf = conf
self.db = db.SQLite3(conf.get('general', 'dbpath'), conf)
self.signer = URLSafeTimedSerializer(self.db.preferences.get("session-key"))
self.markup = html.Markup(conf.section('markup'))
self.hasher = hash.new(conf.section("hash"))
super(Isso, self).__init__(conf)
@ -105,7 +104,7 @@ class Isso(object):
self.urls = Map()
views.Info(self)
comments.API(self)
comments.API(self, self.hasher)
def render(self, text):
return self.markup.render(text)

@ -115,7 +115,10 @@ class Config:
"[markup]",
"options = strikethrough, autolink",
"allowed-elements = ",
"allowed-attributes = "
"allowed-attributes = ",
"[hash]",
"algorithm = pbkdf2",
"salt = Eech7co8Ohloopo9Ol6baimi"
]
@classmethod

@ -35,6 +35,7 @@ class TestComments(unittest.TestCase):
conf = core.Config.load(None)
conf.set("general", "dbpath", self.path)
conf.set("guard", "enabled", "off")
conf.set("hash", "algorithm", "none")
class App(Isso, core.Mixin):
pass
@ -292,7 +293,6 @@ class TestComments(unittest.TestCase):
b = loads(b.data)
c = loads(c.data)
self.assertIsInstance(int(a['hash'], 16), int)
self.assertNotEqual(a['hash'], '192.168.1.1')
self.assertEqual(a['hash'], b['hash'])
self.assertNotEqual(a['hash'], c['hash'])
@ -375,9 +375,6 @@ class TestComments(unittest.TestCase):
# just for the record
self.assertEqual(self.post('/id/1/dislike', content_type=js).status_code, 200)
def testPBKDF2(self):
self.assertEqual(comments.API.pbkdf2(u"", Isso.salt, 1000, 6), u"42476aafe2e4")
class TestModeratedComments(unittest.TestCase):
@ -387,6 +384,7 @@ class TestModeratedComments(unittest.TestCase):
conf.set("general", "dbpath", self.path)
conf.set("moderation", "enabled", "true")
conf.set("guard", "enabled", "off")
conf.set("hash", "algorithm", "none")
class App(Isso, core.Mixin):
pass
@ -418,6 +416,7 @@ class TestPurgeComments(unittest.TestCase):
conf.set("general", "dbpath", self.path)
conf.set("moderation", "enabled", "true")
conf.set("guard", "enabled", "off")
conf.set("hash", "algorithm", "none")
class App(Isso, core.Mixin):
pass

@ -1,5 +1,7 @@
# -*- encoding: utf-8 -*-
from __future__ import unicode_literals
try:
import unittest2 as unittest
except ImportError:
@ -36,6 +38,7 @@ class TestGuard(unittest.TestCase):
conf = core.Config.load(None)
conf.set("general", "dbpath", self.path)
conf.set("hash", "algorithm", "none")
conf.set("guard", "enabled", "true")
conf.set("guard", "ratelimit", str(ratelimit))
conf.set("guard", "direct-reply", str(direct_reply))

@ -0,0 +1,72 @@
# -*- encoding: utf-8 -*-
from __future__ import unicode_literals
try:
import unittest2 as unittest
except ImportError:
import unittest
from isso.compat import PY2K, string_types
from isso.core import Config
from isso.utils.hash import Hash, PBKDF2, new
class TestHasher(unittest.TestCase):
def test_hash(self):
self.assertRaises(TypeError, Hash, "Foo")
self.assertEqual(Hash(b"").salt, b"")
self.assertEqual(Hash().salt, Hash.salt)
h = Hash(b"", func=None)
self.assertRaises(TypeError, h.hash, "...")
self.assertEqual(h.hash(b"..."), b"...")
self.assertIsInstance(h.uhash(u"..."), string_types)
@unittest.skipIf(PY2K, "byte/str quirks")
def test_uhash(self):
h = Hash(b"", func=None)
self.assertRaises(TypeError, h.uhash, b"...")
class TestPBKDF2(unittest.TestCase):
def test_default(self):
pbkdf2 = PBKDF2(iterations=1000) # original setting (and still default)
self.assertEqual(pbkdf2.uhash(""), "42476aafe2e4")
def test_different_salt(self):
a = PBKDF2(b"a", iterations=1)
b = PBKDF2(b"b", iterations=1)
self.assertNotEqual(a.hash(b""), b.hash(b""))
class TestCreate(unittest.TestCase):
def test_default(self):
conf = Config.load(None)
self.assertIsInstance(new(conf.section("hash")), PBKDF2)
def test_custom(self):
def _new(val):
conf = Config.load(None)
conf.set("hash", "algorithm", val)
return new(conf.section("hash"))
sha1 = _new("sha1")
self.assertIsInstance(sha1, Hash)
self.assertEqual(sha1.func, "sha1")
self.assertRaises(ValueError, _new, "foo")
pbkdf2 = _new("pbkdf2:16")
self.assertIsInstance(pbkdf2, PBKDF2)
self.assertEqual(pbkdf2.iterations, 16)
pbkdf2 = _new("pbkdf2:16:2:md5")
self.assertIsInstance(pbkdf2, PBKDF2)
self.assertEqual(pbkdf2.dklen, 2)
self.assertEqual(pbkdf2.func, "md5")

@ -28,6 +28,7 @@ class TestVote(unittest.TestCase):
conf = core.Config.load(None)
conf.set("general", "dbpath", self.path)
conf.set("guard", "enabled", "off")
conf.set("hash", "algorithm", "none")
class App(Isso, core.Mixin):
pass

@ -0,0 +1,112 @@
# -*- encoding: utf-8 -*-
from __future__ import unicode_literals
import codecs
import hashlib
from isso.compat import string_types, text_type as str
try:
from werkzeug.security import pbkdf2_bin as pbkdf2
except ImportError:
try:
from passlib.utils.pbkdf2 import pbkdf2 as _pbkdf2
def pbkdf2(val, salt, iterations, dklen, func):
return _pbkdf2(val, salt, iterations, dklen, ("hmac-" + func).encode("utf-8"))
except ImportError as ex:
raise ImportError("No PBKDF2 implementation found. Either upgrade " +
"to `werkzeug` 0.9 or install `passlib`.")
def _TypeError(name, expected, val):
return TypeError("'{0}' must be {1}, not {2}".format(
name, expected, val.__class__.__name__))
class Hash(object):
func = None
salt = b"Eech7co8Ohloopo9Ol6baimi"
def __init__(self, salt=None, func="sha1"):
if func is not None:
hashlib.new(func) # may not be available
self.func = func
if salt is not None:
if not isinstance(salt, bytes):
raise _TypeError("salt", "bytes", salt)
self.salt = salt
def hash(self, val):
"""Calculate hash from value (must be bytes)."""
if not isinstance(val, bytes):
raise _TypeError("val", "bytes", val)
rv = self.compute(val)
if not isinstance(val, bytes):
raise _TypeError("val", "bytes", rv)
return rv
def uhash(self, val):
"""Calculate hash from unicode value and return hex value as unicode"""
if not isinstance(val, string_types):
raise _TypeError("val", "str", val)
return codecs.encode(self.hash(val.encode("utf-8")), "hex_codec").decode("utf-8")
def compute(self, val):
if self.func is None:
return val
h = hashlib.new(self.func)
h.update(val)
return h.digest()
class PBKDF2(Hash):
def __init__(self, salt=None, iterations=1000, dklen=6, func="sha1"):
super(PBKDF2, self).__init__(salt)
self.iterations = iterations
self.dklen = dklen
self.func = func
def compute(self, val):
return pbkdf2(val, self.salt, self.iterations, self.dklen, self.func)
def new(conf):
"""Factory to create hash functions from configuration section. If an
algorithm takes custom parameters, you can separate them by a colon like
this: pbkdf2:arg1:arg2:arg3."""
algorithm = conf.get("algorithm")
salt = conf.get("salt").encode("utf-8")
if algorithm == "none":
return Hash(salt, None)
elif algorithm.startswith("pbkdf2"):
kwargs = {}
tail = algorithm.partition(":")[2]
for func, key in ((int, "iterations"), (int, "dklen"), (str, "func")):
head, _, tail = tail.partition(":")
if not head:
break
kwargs[key] = func(head)
return PBKDF2(salt, **kwargs)
else:
return Hash(salt, algorithm)
sha1 = Hash(func="sha1").uhash

@ -3,7 +3,6 @@
import re
import cgi
import time
import hashlib
import functools
from itsdangerous import SignatureExpired, BadSignature
@ -20,19 +19,7 @@ from isso.compat import text_type as str
from isso import utils, local
from isso.utils import http, parse, JSONResponse as JSON
from isso.views import requires
try:
from werkzeug.security import pbkdf2_hex
except ImportError:
try:
from passlib.utils.pbkdf2 import pbkdf2
except ImportError as ex:
raise ImportError("No PBKDF2 implementation found. Either upgrade " +
"to `werkzeug` 0.9 or install `passlib`.")
else:
import base64
pbkdf2_hex = lambda text, salt, iterations, dklen: base64.b16encode(
pbkdf2(text.encode("utf-8"), salt, iterations, dklen)).lower().decode("utf-8")
from isso.utils.hash import sha1
# from Django appearently, looks good to me *duck*
__url_re = re.compile(
@ -56,10 +43,6 @@ def normalize(url):
return url
def sha1(text):
return hashlib.sha1(text.encode('utf-8')).hexdigest()
def xhr(func):
"""A decorator to check for CSRF on POST/PUT/DELETE using a <form>
element and JS to execute automatically (see #40 for a proof-of-concept).
@ -107,9 +90,10 @@ class API(object):
('demo', ('GET', '/demo'))
]
def __init__(self, isso):
def __init__(self, isso, hasher):
self.isso = isso
self.hash = hasher.uhash
self.cache = isso.cache
self.signal = isso.signal
@ -151,11 +135,6 @@ class API(object):
return True, ""
@classmethod
def pbkdf2(cls, text, salt, iterations, dklen):
# werkzeug.security.pbkdf2_hex returns always the native string type
return pbkdf2_hex(text.encode("utf-8"), salt, iterations, dklen)
@xhr
@requires(str, 'uri')
def new(self, environ, request, uri):
@ -214,7 +193,7 @@ class API(object):
max_age=self.conf.getint('max-age'))
rv["text"] = self.isso.render(rv["text"])
rv["hash"] = API.pbkdf2(rv['email'] or rv['remote_addr'], self.isso.salt, 1000, 6)
rv["hash"] = self.hash(rv['email'] or rv['remote_addr'])
self.cache.set('hash', (rv['email'] or rv['remote_addr']).encode('utf-8'), rv['hash'])
@ -446,7 +425,7 @@ class API(object):
val = self.cache.get('hash', key.encode('utf-8'))
if val is None:
val = API.pbkdf2(key, self.isso.salt, 1000, 6)
val = self.hash(key)
self.cache.set('hash', key.encode('utf-8'), val)
item['hash'] = val

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