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store sessions in cookies, needs logic in main, thanks Nick Groenke

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This commit is contained in:
Massimo Di Pierro
2012-06-10 01:18:30 -05:00
parent 6e136a6b47
commit dc5d075bc8
3 changed files with 559 additions and 7 deletions
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VERSION
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@@ -1 +1 @@
Version 2.00.0 (2012-06-10 00:32:10) dev
Version 2.00.0 (2012-06-10 01:18:28) dev
gluon/contrib/aes.py
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"""Simple AES cipher implementation in pure Python following PEP-272 API
Homepage: https://bitbucket.org/intgr/pyaes/
The goal of this module is to be as fast as reasonable in Python while still
being Pythonic and readable/understandable. It is licensed under the permissive
MIT license.
Hopefully the code is readable and commented enough that it can serve as an
introduction to the AES cipher for Python coders. In fact, it should go along
well with the Stick Figure Guide to AES:
http://www.moserware.com/2009/09/stick-figure-guide-to-advanced.html
Contrary to intuition, this implementation numbers the 4x4 matrices from top to
bottom for efficiency reasons::
0 4 8 12
1 5 9 13
2 6 10 14
3 7 11 15
Effectively it's the transposition of what you'd expect. This actually makes
the code simpler -- except the ShiftRows step, but hopefully the explanation
there clears it up.
"""
####
# Copyright (c) 2010 Marti Raudsepp <marti@juffo.org>
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.
####
from array import array
# Globals mandated by PEP 272:
# http://www.python.org/dev/peps/pep-0272/
MODE_ECB = 1
MODE_CBC = 2
#MODE_CTR = 6
block_size = 16
key_size = None
def new(key, mode=MODE_CBC, IV=None):
if mode == MODE_ECB:
return ECBMode(AES(key))
elif mode == MODE_CBC:
if IV is None:
raise ValueError, "CBC mode needs an IV value!"
return CBCMode(AES(key), IV)
else:
raise NotImplementedError
#### AES cipher implementation
class AES(object):
block_size = 16
def __init__(self, key):
self.setkey(key)
def setkey(self, key):
"""Sets the key and performs key expansion."""
self.key = key
self.key_size = len(key)
if self.key_size == 16:
self.rounds = 10
elif self.key_size == 24:
self.rounds = 12
elif self.key_size == 32:
self.rounds = 14
else:
raise ValueError, "Key length must be 16, 24 or 32 bytes"
self.expand_key()
def expand_key(self):
"""Performs AES key expansion on self.key and stores in self.exkey"""
# The key schedule specifies how parts of the key are fed into the
# cipher's round functions. "Key expansion" means performing this
# schedule in advance. Almost all implementations do this.
#
# Here's a description of AES key schedule:
# http://en.wikipedia.org/wiki/Rijndael_key_schedule
# The expanded key starts with the actual key itself
exkey = array('B', self.key)
# extra key expansion steps
if self.key_size == 16:
extra_cnt = 0
elif self.key_size == 24:
extra_cnt = 2
else:
extra_cnt = 3
# 4-byte temporary variable for key expansion
word = exkey[-4:]
# Each expansion cycle uses 'i' once for Rcon table lookup
for i in xrange(1, 11):
#### key schedule core:
# left-rotate by 1 byte
word = word[1:4] + word[0:1]
# apply S-box to all bytes
for j in xrange(4):
word[j] = aes_sbox[word[j]]
# apply the Rcon table to the leftmost byte
word[0] = word[0] ^ aes_Rcon[i]
#### end key schedule core
for z in xrange(4):
for j in xrange(4):
# mix in bytes from the last subkey
word[j] ^= exkey[-self.key_size + j]
exkey.extend(word)
# Last key expansion cycle always finishes here
if len(exkey) >= (self.rounds+1) * self.block_size:
break
# Special substitution step for 256-bit key
if self.key_size == 32:
for j in xrange(4):
# mix in bytes from the last subkey XORed with S-box of
# current word bytes
word[j] = aes_sbox[word[j]] ^ exkey[-self.key_size + j]
exkey.extend(word)
# Twice for 192-bit key, thrice for 256-bit key
for z in xrange(extra_cnt):
for j in xrange(4):
# mix in bytes from the last subkey
word[j] ^= exkey[-self.key_size + j]
exkey.extend(word)
self.exkey = exkey
def add_round_key(self, block, round):
"""AddRoundKey step in AES. This is where the key is mixed into plaintext"""
offset = round * 16
exkey = self.exkey
for i in xrange(16):
block[i] ^= exkey[offset + i]
#print 'AddRoundKey:', block
def sub_bytes(self, block, sbox):
"""SubBytes step, apply S-box to all bytes
Depending on whether encrypting or decrypting, a different sbox array
is passed in.
"""
for i in xrange(16):
block[i] = sbox[block[i]]
#print 'SubBytes :', block
def shift_rows(self, b):
"""ShiftRows step. Shifts 2nd row to left by 1, 3rd row by 2, 4th row by 3
Since we're performing this on a transposed matrix, cells are numbered
from top to bottom::
0 4 8 12 -> 0 4 8 12 -- 1st row doesn't change
1 5 9 13 -> 5 9 13 1 -- row shifted to left by 1 (wraps around)
2 6 10 14 -> 10 14 2 6 -- shifted by 2
3 7 11 15 -> 15 3 7 11 -- shifted by 3
"""
b[1], b[5], b[ 9], b[13] = b[ 5], b[ 9], b[13], b[ 1]
b[2], b[6], b[10], b[14] = b[10], b[14], b[ 2], b[ 6]
b[3], b[7], b[11], b[15] = b[15], b[ 3], b[ 7], b[11]
#print 'ShiftRows :', b
def shift_rows_inv(self, b):
"""Similar to shift_rows above, but performed in inverse for decryption."""
b[ 5], b[ 9], b[13], b[ 1] = b[1], b[5], b[ 9], b[13]
b[10], b[14], b[ 2], b[ 6] = b[2], b[6], b[10], b[14]
b[15], b[ 3], b[ 7], b[11] = b[3], b[7], b[11], b[15]
#print 'ShiftRows :', b
def mix_columns(self, block):
"""MixColumns step. Mixes the values in each column"""
# Cache global multiplication tables (see below)
mul_by_2 = gf_mul_by_2
mul_by_3 = gf_mul_by_3
# Since we're dealing with a transposed matrix, columns are already
# sequential
for i in xrange(4):
col = i * 4
#v0, v1, v2, v3 = block[col : col+4]
v0, v1, v2, v3 = (block[col], block[col + 1], block[col + 2],
block[col + 3])
block[col ] = mul_by_2[v0] ^ v3 ^ v2 ^ mul_by_3[v1]
block[col+1] = mul_by_2[v1] ^ v0 ^ v3 ^ mul_by_3[v2]
block[col+2] = mul_by_2[v2] ^ v1 ^ v0 ^ mul_by_3[v3]
block[col+3] = mul_by_2[v3] ^ v2 ^ v1 ^ mul_by_3[v0]
#print 'MixColumns :', block
def mix_columns_inv(self, block):
"""Similar to mix_columns above, but performed in inverse for decryption."""
# Cache global multiplication tables (see below)
mul_9 = gf_mul_by_9
mul_11 = gf_mul_by_11
mul_13 = gf_mul_by_13
mul_14 = gf_mul_by_14
# Since we're dealing with a transposed matrix, columns are already
# sequential
for i in xrange(4):
col = i * 4
v0, v1, v2, v3 = (block[col], block[col + 1], block[col + 2],
block[col + 3])
#v0, v1, v2, v3 = block[col:col+4]
block[col ] = mul_14[v0] ^ mul_9[v3] ^ mul_13[v2] ^ mul_11[v1]
block[col+1] = mul_14[v1] ^ mul_9[v0] ^ mul_13[v3] ^ mul_11[v2]
block[col+2] = mul_14[v2] ^ mul_9[v1] ^ mul_13[v0] ^ mul_11[v3]
block[col+3] = mul_14[v3] ^ mul_9[v2] ^ mul_13[v1] ^ mul_11[v0]
#print 'MixColumns :', block
def encrypt_block(self, block):
"""Encrypts a single block. This is the main AES function"""
# For efficiency reasons, the state between steps is transmitted via a
# mutable array, not returned.
self.add_round_key(block, 0)
for round in xrange(1, self.rounds):
self.sub_bytes(block, aes_sbox)
self.shift_rows(block)
self.mix_columns(block)
self.add_round_key(block, round)
self.sub_bytes(block, aes_sbox)
self.shift_rows(block)
# no mix_columns step in the last round
self.add_round_key(block, self.rounds)
def decrypt_block(self, block):
"""Decrypts a single block. This is the main AES decryption function"""
# For efficiency reasons, the state between steps is transmitted via a
# mutable array, not returned.
self.add_round_key(block, self.rounds)
# count rounds down from 15 ... 1
for round in xrange(self.rounds-1, 0, -1):
self.shift_rows_inv(block)
self.sub_bytes(block, aes_inv_sbox)
self.add_round_key(block, round)
self.mix_columns_inv(block)
self.shift_rows_inv(block)
self.sub_bytes(block, aes_inv_sbox)
self.add_round_key(block, 0)
# no mix_columns step in the last round
#### ECB mode implementation
class ECBMode(object):
"""Electronic CodeBook (ECB) mode encryption.
Basically this mode applies the cipher function to each block individually;
no feedback is done. NB! This is insecure for almost all purposes
"""
def __init__(self, cipher):
self.cipher = cipher
self.block_size = cipher.block_size
def ecb(self, data, block_func):
"""Perform ECB mode with the given function"""
if len(data) % self.block_size != 0:
raise ValueError, "Plaintext length must be multiple of 16"
block_size = self.block_size
data = array('B', data)
for offset in xrange(0, len(data), block_size):
block = data[offset : offset+block_size]
block_func(block)
data[offset : offset+block_size] = block
return data.tostring()
def encrypt(self, data):
"""Encrypt data in ECB mode"""
return self.ecb(data, self.cipher.encrypt_block)
def decrypt(self, data):
"""Decrypt data in ECB mode"""
return self.ecb(data, self.cipher.decrypt_block)
#### CBC mode
class CBCMode(object):
"""Cipher Block Chaining (CBC) mode encryption. This mode avoids content leaks.
In CBC encryption, each plaintext block is XORed with the ciphertext block
preceding it; decryption is simply the inverse.
"""
# A better explanation of CBC can be found here:
# http://en.wikipedia.org/wiki/Block_cipher_modes_of_operation#Cipher-block_chaining_.28CBC.29
def __init__(self, cipher, IV):
self.cipher = cipher
self.block_size = cipher.block_size
self.IV = array('B', IV)
def encrypt(self, data):
"""Encrypt data in CBC mode"""
block_size = self.block_size
if len(data) % block_size != 0:
raise ValueError, "Plaintext length must be multiple of 16"
data = array('B', data)
IV = self.IV
for offset in xrange(0, len(data), block_size):
block = data[offset : offset+block_size]
# Perform CBC chaining
for i in xrange(block_size):
block[i] ^= IV[i]
self.cipher.encrypt_block(block)
data[offset : offset+block_size] = block
IV = block
self.IV = IV
return data.tostring()
def decrypt(self, data):
"""Decrypt data in CBC mode"""
block_size = self.block_size
if len(data) % block_size != 0:
raise ValueError, "Ciphertext length must be multiple of 16"
data = array('B', data)
IV = self.IV
for offset in xrange(0, len(data), block_size):
ctext = data[offset : offset+block_size]
block = ctext[:]
self.cipher.decrypt_block(block)
# Perform CBC chaining
#for i in xrange(block_size):
# data[offset + i] ^= IV[i]
for i in xrange(block_size):
block[i] ^= IV[i]
data[offset : offset+block_size] = block
IV = ctext
#data[offset : offset+block_size] = block
self.IV = IV
return data.tostring()
####
def galois_multiply(a, b):
"""Galois Field multiplicaiton for AES"""
p = 0
while b:
if b & 1:
p ^= a
a <<= 1
if a & 0x100:
a ^= 0x1b
b >>= 1
return p & 0xff
# Precompute the multiplication tables for encryption
gf_mul_by_2 = array('B', [galois_multiply(x, 2) for x in range(256)])
gf_mul_by_3 = array('B', [galois_multiply(x, 3) for x in range(256)])
# ... for decryption
gf_mul_by_9 = array('B', [galois_multiply(x, 9) for x in range(256)])
gf_mul_by_11 = array('B', [galois_multiply(x, 11) for x in range(256)])
gf_mul_by_13 = array('B', [galois_multiply(x, 13) for x in range(256)])
gf_mul_by_14 = array('B', [galois_multiply(x, 14) for x in range(256)])
####
# The S-box is a 256-element array, that maps a single byte value to another
# byte value. Since it's designed to be reversible, each value occurs only once
# in the S-box
#
# More information: http://en.wikipedia.org/wiki/Rijndael_S-box
aes_sbox = array('B',
'637c777bf26b6fc53001672bfed7ab76'
'ca82c97dfa5947f0add4a2af9ca472c0'
'b7fd9326363ff7cc34a5e5f171d83115'
'04c723c31896059a071280e2eb27b275'
'09832c1a1b6e5aa0523bd6b329e32f84'
'53d100ed20fcb15b6acbbe394a4c58cf'
'd0efaafb434d338545f9027f503c9fa8'
'51a3408f929d38f5bcb6da2110fff3d2'
'cd0c13ec5f974417c4a77e3d645d1973'
'60814fdc222a908846eeb814de5e0bdb'
'e0323a0a4906245cc2d3ac629195e479'
'e7c8376d8dd54ea96c56f4ea657aae08'
'ba78252e1ca6b4c6e8dd741f4bbd8b8a'
'703eb5664803f60e613557b986c11d9e'
'e1f8981169d98e949b1e87e9ce5528df'
'8ca1890dbfe6426841992d0fb054bb16'.decode('hex')
)
# This is the inverse of the above. In other words:
# aes_inv_sbox[aes_sbox[val]] == val
aes_inv_sbox = array('B',
'52096ad53036a538bf40a39e81f3d7fb'
'7ce339829b2fff87348e4344c4dee9cb'
'547b9432a6c2233dee4c950b42fac34e'
'082ea16628d924b2765ba2496d8bd125'
'72f8f66486689816d4a45ccc5d65b692'
'6c704850fdedb9da5e154657a78d9d84'
'90d8ab008cbcd30af7e45805b8b34506'
'd02c1e8fca3f0f02c1afbd0301138a6b'
'3a9111414f67dcea97f2cfcef0b4e673'
'96ac7422e7ad3585e2f937e81c75df6e'
'47f11a711d29c5896fb7620eaa18be1b'
'fc563e4bc6d279209adbc0fe78cd5af4'
'1fdda8338807c731b11210592780ec5f'
'60517fa919b54a0d2de57a9f93c99cef'
'a0e03b4dae2af5b0c8ebbb3c83539961'
'172b047eba77d626e169146355210c7d'.decode('hex')
)
# The Rcon table is used in AES's key schedule (key expansion)
# It's a pre-computed table of exponentation of 2 in AES's finite field
#
# More information: http://en.wikipedia.org/wiki/Rijndael_key_schedule
aes_Rcon = array('B',
'8d01020408102040801b366cd8ab4d9a'
'2f5ebc63c697356ad4b37dfaefc59139'
'72e4d3bd61c29f254a943366cc831d3a'
'74e8cb8d01020408102040801b366cd8'
'ab4d9a2f5ebc63c697356ad4b37dfaef'
'c5913972e4d3bd61c29f254a943366cc'
'831d3a74e8cb8d01020408102040801b'
'366cd8ab4d9a2f5ebc63c697356ad4b3'
'7dfaefc5913972e4d3bd61c29f254a94'
'3366cc831d3a74e8cb8d010204081020'
'40801b366cd8ab4d9a2f5ebc63c69735'
'6ad4b37dfaefc5913972e4d3bd61c29f'
'254a943366cc831d3a74e8cb8d010204'
'08102040801b366cd8ab4d9a2f5ebc63'
'c697356ad4b37dfaefc5913972e4d3bd'
'61c29f254a943366cc831d3a74e8cb'.decode('hex')
)
gluon/globals.py
+56 -6
View File
@@ -36,6 +36,13 @@ import os
import sys
import traceback
import threading
import hmac
import base64
try:
from Crypto.Cipher import AES
except ImportError:
from contrib import aes as AES
try:
from gluon.contrib.minify import minify
@@ -409,6 +416,7 @@ class Session(Storage):
migrate=True,
separate = None,
check_client=False,
cookie_key=None,
):
"""
separate can be separate=lambda(session_name): session_name[-2:]
@@ -421,9 +429,30 @@ class Session(Storage):
if not masterapp:
masterapp = request.application
response.session_id_name = 'session_id_%s' % masterapp.lower()
# Load session data from cookie
if cookie_key:
response.session_cookie_key = cookie_key
response.session_cookie_key2 = hashlib.md5(cookie_key).digest()
cookie_name = request.application.lower()+'_session_data'
response.session_cookie_name = cookie_name
if cookie_data in request.cookies:
cookie_value = request.cookies[cookie_name].value
cookie_parts = cookie_value.split(":")
enc = cookie_parts[2]
cipher = AES.new(cookie_key)
decrypted = cipher.decrypt(base64.b64decode(enc)).rstrip('{')
check = hmac.new(response.session_cookie_key2,enc).hexdigest()
if cookie_parts[0] == check:
session_data = cPickle.loads(decrypted)
self.update(session_data)
else:
return
if not db:
if global_settings.db_sessions is True or masterapp in global_settings.db_sessions:
if global_settings.db_sessions is True \
or masterapp in global_settings.db_sessions:
return
response.session_new = False
client = request.client and request.client.replace(':', '.')
@@ -441,11 +470,13 @@ class Session(Storage):
response.session_file = \
open(response.session_filename, 'rb+')
try:
portalocker.lock(response.session_file,portalocker.LOCK_EX)
portalocker.lock(response.session_file,
portalocker.LOCK_EX)
response.session_locked = True
self.update(cPickle.load(response.session_file))
response.session_file.seek(0)
oc = response.session_filename.split('/')[-1].split('-')[0]
oc = response.session_filename.split('/')[-1]\
.split('-')[0]
if check_client and client!=oc:
raise Exception, "cookie attack"
finally:
@@ -459,7 +490,8 @@ class Session(Storage):
response.session_id = '%s-%s' % (client, uuid)
if separate:
prefix = separate(response.session_id)
response.session_id = '%s/%s' % (prefix,response.session_id)
response.session_id = '%s/%s' % \
(prefix,response.session_id)
response.session_filename = \
os.path.join(up(request.folder), masterapp,
'sessions', response.session_id)
@@ -492,16 +524,25 @@ class Session(Storage):
migrate=table_migrate,
)
try:
# Get session data out of the database
# Key comes from the cookie
key = request.cookies[response.session_id_name].value
(record_id, unique_key) = key.split(':')
if record_id == '0':
raise Exception, 'record_id == 0'
# Select from database.
rows = db(table.id == record_id).select()
# Make sure the session data exists in the database
if len(rows) == 0 or rows[0].unique_key != unique_key:
raise Exception, 'No record'
# rows[0].update_record(locked=True)
# Unpickle the data
session_data = cPickle.loads(rows[0].session_data)
self.update(session_data)
except Exception:
@@ -540,8 +581,18 @@ class Session(Storage):
self._close(response)
self._forget = True
def _try_store_in_db(self, request, response):
def _try_store_in_cookie(self, request, response):
pad = lambda s: s + (32 - len(s) % 32) * '{'
data = cPickle.dumps(dict(self))
cipher = AES.new(response.session_cookie_key)
encrypted_data = base64.b64encode(cipher.encrypt(pad(data)))
signature = hmac.new(response.session_cookie_key2,encrypted_data)\
.hexdigest()
value = signature+':'+encrypted_data
response.cookies[response.session_cookie_name] = value
response.cookies[response.session_cookie_name]['path'] = '/'
def _try_store_in_db(self, request, response):
# don't save if file-based sessions, no session id, or session being forgotten
if not response.session_db or not response.session_id or self._forget:
return
@@ -618,4 +669,3 @@ class Session(Storage):