diff options
| -rw-r--r-- | docs/api/session.rst | 5 | ||||
| -rw-r--r-- | pyramid/session.py | 51 | ||||
| -rw-r--r-- | pyramid/tests/test_session.py | 26 |
3 files changed, 56 insertions, 26 deletions
diff --git a/docs/api/session.rst b/docs/api/session.rst index daed9fc33..12b727183 100644 --- a/docs/api/session.rst +++ b/docs/api/session.rst @@ -7,3 +7,8 @@ .. autofunction:: InsecureCookieSessionFactoryConfig + .. autofunction:: signed_serialize + + .. autofunction:: signed_deserialize + + diff --git a/pyramid/session.py b/pyramid/session.py index 158468152..95d790a7b 100644 --- a/pyramid/session.py +++ b/pyramid/session.py @@ -110,9 +110,15 @@ def InsecureCookieSessionFactoryConfig( now = time.time() created = accessed = now new = True - cookieval = request.cookies.get(self._cookie_name) - value = deserialize(cookieval, self._secret) + value = None state = {} + cookieval = request.cookies.get(self._cookie_name) + if cookieval is not None: + try: + value = signed_deserialize(cookieval, self._secret) + except ValueError: + value = None + if value is not None: accessed, created, state = value new = False @@ -162,7 +168,7 @@ def InsecureCookieSessionFactoryConfig( exception = getattr(self.request, 'exception', None) if exception is not None: # dont set a cookie during exceptions return False - cookieval = serialize( + cookieval = signed_serialize( (self.accessed, self.created, dict(self)), self._secret ) if len(cookieval) > 4064: @@ -193,22 +199,43 @@ def InsecureCookieSessionFactoryConfig( return InsecureCookieSessionFactory -def serialize(data, secret): +def signed_serialize(data, secret): + """ Serialize any pickleable structure (``data``) and sign it + using the ``secret`` (must be a string). Return the + serialization, which includes the signature as its first 40 bytes. + The ``signed_deserialize`` method will deserialize such a value. + + This function is useful for creating signed cookies. For example: + + .. code-block:: python + + cookieval = signed_serialize({'a':1}, 'secret') + response.set_cookie('signed_cookie', cookieval) + """ pickled = pickle.dumps(data, pickle.HIGHEST_PROTOCOL) sig = hmac.new(secret, pickled, sha1).hexdigest() return sig + base64.standard_b64encode(pickled) -def deserialize(serialized, secret, hmac=hmac): - # hmac parameterized only for unit tests - if serialized is None: - return None +def signed_deserialize(serialized, secret, hmac=hmac): + """ Deserialize the value returned from ``signed_serialize``. If + the value cannot be deserialized for any reason, a + :exc:`ValueError` exception will be raised. + + This function is useful for deserializing a signed cookie value + created by ``signed_serialize``. For example: + .. code-block:: python + + cookieval = request.cookies['signed_cookie'] + data = signed_deserialize(cookieval, 'secret') + """ + # hmac parameterized only for unit tests try: input_sig, pickled = (serialized[:40], base64.standard_b64decode(serialized[40:])) - except (binascii.Error, TypeError): + except (binascii.Error, TypeError), e: # Badly formed data can make base64 die - return None + raise ValueError('Badly formed base64 data: %s' % e) sig = hmac.new(secret, pickled, sha1).hexdigest() @@ -216,7 +243,7 @@ def deserialize(serialized, secret, hmac=hmac): # have no idea what it means) if len(sig) != len(input_sig): - return None + raise ValueError('Wrong signature length') invalid_bits = 0 @@ -224,7 +251,7 @@ def deserialize(serialized, secret, hmac=hmac): invalid_bits += a != b if invalid_bits: - return None + raise ValueError('Invalid bits in signature') return pickle.loads(pickled) diff --git a/pyramid/tests/test_session.py b/pyramid/tests/test_session.py index 12f70bab9..07ca06c81 100644 --- a/pyramid/tests/test_session.py +++ b/pyramid/tests/test_session.py @@ -12,8 +12,8 @@ class TestInsecureCookieSession(unittest.TestCase): self.assertEqual(dict(session), {}) def _serialize(self, accessed, state, secret='secret'): - from pyramid.session import serialize - return serialize((accessed, accessed, state), secret) + from pyramid.session import signed_serialize + return signed_serialize((accessed, accessed, state), secret) def test_ctor_with_cookie_still_valid(self): import time @@ -172,22 +172,22 @@ def serialize(data, secret): sig = hmac.new(secret, pickled, sha1).hexdigest() return sig + base64.standard_b64encode(pickled) -class Test_serialize(unittest.TestCase): +class Test_signed_serialize(unittest.TestCase): def _callFUT(self, data, secret): - from pyramid.session import serialize - return serialize(data, secret) + from pyramid.session import signed_serialize + return signed_serialize(data, secret) def test_it(self): expected = serialize('123', 'secret') result = self._callFUT('123', 'secret') self.assertEqual(result, expected) -class Test_deserialize(unittest.TestCase): +class Test_signed_deserialize(unittest.TestCase): def _callFUT(self, serialized, secret, hmac=None): if hmac is None: import hmac - from pyramid.session import deserialize - return deserialize(serialized, secret, hmac=hmac) + from pyramid.session import signed_deserialize + return signed_deserialize(serialized, secret, hmac=hmac) def test_it(self): serialized = serialize('123', 'secret') @@ -196,8 +196,7 @@ class Test_deserialize(unittest.TestCase): def test_invalid_bits(self): serialized = serialize('123', 'secret') - result = self._callFUT(serialized, 'seekrit') - self.assertEqual(result, None) + self.assertRaises(ValueError, self._callFUT, serialized, 'seekrit') def test_invalid_len(self): class hmac(object): @@ -206,13 +205,12 @@ class Test_deserialize(unittest.TestCase): def hexdigest(self): return '1234' serialized = serialize('123', 'secret123') - result = self._callFUT(serialized, 'secret', hmac=hmac()) - self.assertEqual(result, None) + self.assertRaises(ValueError, self._callFUT, serialized, 'secret', + hmac=hmac()) def test_it_bad_encoding(self): serialized = 'bad' + serialize('123', 'secret') - result = self._callFUT(serialized, 'secret') - self.assertEqual(result, None) + self.assertRaises(ValueError, self._callFUT, serialized, 'secret') class DummySessionFactory(dict): |