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mirror of https://github.com/xcat2/confluent.git synced 2025-01-16 20:57:53 +00:00
Jarrod Johnson 919dab9b55 Create auth multiprocessing pool on demand
Most of the time, we don't need this pool.  Create when needed,
and clean up after 30 seconds of inactivity.  This avoids a slow
shutdown that was due to core python hanging in help_finish_stuff,
and as a bonus means most of the time, one only sees one confluent
process, which has been a source of questions already.
2017-03-05 08:28:35 -05:00

234 lines
8.6 KiB
Python

# vim: tabstop=4 shiftwidth=4 softtabstop=4
# Copyright 2014 IBM Corporation
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
# authentication and authorization routines for confluent
# authentication scheme caches passphrase values to help HTTP Basic auth
# the PBKDF2 transform is skipped unless a user has been idle for sufficient
# time
import confluent.config.configmanager as configmanager
import eventlet
import eventlet.tpool
import Crypto.Protocol.KDF as KDF
import hashlib
import hmac
import multiprocessing
try:
import PAM
except ImportError:
pass
import time
_pamservice = 'confluent'
_passcache = {}
_passchecking = {}
authworkers = None
authcleaner = None
class Credentials(object):
def __init__(self, username, passphrase):
self.username = username
self.passphrase = passphrase
self.haspam = False
def pam_conv(self, auth, query_list):
# use stored credentials in a pam conversation
self.haspam = True
resp = []
for query_entry in query_list:
query, pamtype = query_entry
if query.startswith('Password'):
resp.append((self.passphrase, 0))
else:
return None
return resp
def _prune_passcache():
# This function makes sure we don't remember a passphrase in memory more
# than 10 seconds
while True:
curtime = time.time()
for passent in _passcache.iterkeys():
if passent[2] < curtime - 10:
del _passcache[passent]
eventlet.sleep(10)
def _get_usertenant(name, tenant=False):
"""_get_usertenant
Convenience function to parse name into username and tenant.
If tenant is explicitly passed in, then name must be the username
tenant name with '/' is forbidden. If '/' is seen in name, tenant
is assumed to preface the /.
If the username is a tenant name, then it is to be the implied
administrator account a tenant gets.
Otherwise, just assume a user in the default tenant
"""
if not isinstance(tenant, bool):
# if not boolean, it must be explicit tenant
user = name
elif '/' in name: # tenant scoped name
tenant, user = name.split('/', 1)
elif configmanager.is_tenant(name):
# the account is the implicit tenant owner account
user = name
tenant = name
else: # assume it is a non-tenant user account
user = name
tenant = None
yield user
yield tenant
def authorize(name, element, tenant=False, operation='create',
skipuserobj=False):
#TODO: actually use the element to ascertain if this user is good enough
"""Determine whether the given authenticated name is authorized.
:param name: The shortname authenticated by the authentication scheme
:param element: The path being examined.
:param tenant: The tenant under which the account exists (defaults to
detect from name)
:param operation: Defaults to checking for 'create' level access
returns None if authorization fails or a tuple of the user object
and the relevant ConfigManager object for the context of the
request.
"""
if operation not in ('create', 'start', 'update', 'retrieve', 'delete'):
return None
user, tenant = _get_usertenant(name, tenant)
if tenant is not None and not configmanager.is_tenant(tenant):
return None
manager = configmanager.ConfigManager(tenant, username=user)
if skipuserobj:
return None, manager, user, tenant, skipuserobj
userobj = manager.get_user(user)
if userobj: # returning
return userobj, manager, user, tenant, skipuserobj
return None
def check_user_passphrase(name, passphrase, element=None, tenant=False):
"""Check a a login name and passphrase for authenticity and authorization
The function combines authentication and authorization into one function.
It is highly recommended for a session layer to provide some secure means
of protecting a session once this function works once and calling
authorize() in order to provide best performance regardless of
circumstance. The function makes effort to provide good performance
in repeated invocation, but that facility will slow down to deter
detected passphrase guessing activity when such activity is detected.
:param name: The login name provided by client
:param passphrase: The passphrase provided by client
:param element: Optional specification of a particular destination
:param tenant: Optional explicit indication of tenant (defaults to
embedded in name)
"""
# The reason why tenant is 'False' instead of 'None':
# None means explicitly not a tenant. False means check
# the username for signs of being a tenant
# If there is any sign of guessing on a user, all valid and
# invalid attempts are equally slowed to no more than 20 per second
# for that particular user.
# similarly, guessing usernames is throttled to 20/sec
user, tenant = _get_usertenant(name, tenant)
while (user, tenant) in _passchecking:
# Want to serialize passphrase checking activity
# by a user, which might be malicious
# would normally make an event and wait
# but here there's no need for that
eventlet.sleep(0.5)
credobj = Credentials(user, passphrase)
try:
pammy = PAM.pam()
pammy.start(_pamservice, user, credobj.pam_conv)
pammy.authenticate()
pammy.acct_mgmt()
del pammy
return authorize(user, element, tenant, skipuserobj=False)
except NameError:
pass
except PAM.error:
if credobj.haspam:
return None
if (user, tenant) in _passcache:
if passphrase == _passcache[(user, tenant)]:
return authorize(user, element, tenant)
else:
# In case of someone trying to guess,
# while someone is legitimately logged in
# invalidate cache and force the slower check
del _passcache[(user, tenant)]
return None
cfm = configmanager.ConfigManager(tenant, username=user)
ucfg = cfm.get_user(user)
if ucfg is None or 'cryptpass' not in ucfg:
eventlet.sleep(0.05) # stall even on test for existence of a username
return None
_passchecking[(user, tenant)] = True
# TODO(jbjohnso): WORKERPOOL
# PBKDF2 is, by design, cpu intensive
# throw it at the worker pool when implemented
# maybe a distinct worker pool, wondering about starving out non-auth stuff
salt, crypt = ucfg['cryptpass']
# execute inside tpool to get greenthreads to give it a special thread
# world
#TODO(jbjohnso): util function to generically offload a call
#such a beast could be passed into pyghmi as a way for pyghmi to
#magically get offload of the crypto functions without having
#to explicitly get into the eventlet tpool game
global authworkers
global authcleaner
if authworkers is None:
authworkers = multiprocessing.Pool(processes=1)
else:
authcleaner.cancel()
authcleaner = eventlet.spawn_after(30, _clean_authworkers)
crypted = eventlet.tpool.execute(_do_pbkdf, passphrase, salt)
del _passchecking[(user, tenant)]
eventlet.sleep(0.05) # either way, we want to stall so that client can't
# determine failure because there is a delay, valid response will
# delay as well
if crypt == crypted:
_passcache[(user, tenant)] = passphrase
return authorize(user, element, tenant)
return None
def _apply_pbkdf(passphrase, salt):
return KDF.PBKDF2(passphrase, salt, 32, 10000,
lambda p, s: hmac.new(p, s, hashlib.sha256).digest())
def _clean_authworkers():
global authworkers
global authcleaner
authworkers = None
authcleaner = None
def _do_pbkdf(passphrase, salt):
# we must get it over to the authworkers pool or else get blocked in
# compute. However, we do want to wait for result, so we have
# one of the exceedingly rare sort of circumstances where 'apply'
# actually makes sense
return authworkers.apply(_apply_pbkdf, [passphrase, salt])