freeipa/ipalib/rpc.py
Rob Crittenden fb7575d6b7 Close connection after each request, avoid NSS shutdown problem.
The unit tests were failing when executed against an Apache server
in F-18 due to dangling references causing NSS shutdown to fail.

https://fedorahosted.org/freeipa/ticket/3180
2012-10-24 15:07:53 -04:00

591 lines
22 KiB
Python

# Authors:
# Jason Gerard DeRose <jderose@redhat.com>
# Rob Crittenden <rcritten@redhat.com>
#
# Copyright (C) 2008 Red Hat
# see file 'COPYING' for use and warranty information
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
"""
RPC client and shared RPC client/server functionality.
This module adds some additional functionality on top of the ``xmlrpclib``
module in the Python standard library. For documentation on the
``xmlrpclib`` module, see:
http://docs.python.org/library/xmlrpclib.html
Also see the `ipaserver.rpcserver` module.
"""
from types import NoneType
from decimal import Decimal
import threading
import sys
import os
import errno
import locale
from xmlrpclib import (Binary, Fault, dumps, loads, ServerProxy, Transport,
ProtocolError, MININT, MAXINT)
import kerberos
from dns import resolver, rdatatype
from dns.exception import DNSException
from ipalib.backend import Connectible
from ipalib.errors import public_errors, PublicError, UnknownError, NetworkError, KerberosError, XMLRPCMarshallError
from ipalib import errors
from ipalib.request import context, Connection
from ipalib.util import get_current_principal
from ipapython import ipautil
from ipapython import kernel_keyring
from ipalib.text import _
import httplib
import socket
from ipapython.nsslib import NSSHTTPS, NSSConnection
from nss.error import NSPRError
from urllib2 import urlparse
from ipalib.krb_utils import KRB5KDC_ERR_S_PRINCIPAL_UNKNOWN, KRB5KRB_AP_ERR_TKT_EXPIRED, \
KRB5_FCC_PERM, KRB5_FCC_NOFILE, KRB5_CC_FORMAT, KRB5_REALM_CANT_RESOLVE
from ipapython.dn import DN
COOKIE_NAME = 'ipa_session_cookie:%s'
def xml_wrap(value):
"""
Wrap all ``str`` in ``xmlrpclib.Binary``.
Because ``xmlrpclib.dumps()`` will itself convert all ``unicode`` instances
into UTF-8 encoded ``str`` instances, we don't do it here.
So in total, when encoding data for an XML-RPC packet, the following
transformations occur:
* All ``str`` instances are treated as binary data and are wrapped in
an ``xmlrpclib.Binary()`` instance.
* Only ``unicode`` instances are treated as character data. They get
converted to UTF-8 encoded ``str`` instances (although as mentioned,
not by this function).
Also see `xml_unwrap()`.
:param value: The simple scalar or simple compound value to wrap.
"""
if type(value) in (list, tuple):
return tuple(xml_wrap(v) for v in value)
if isinstance(value, dict):
return dict(
(k, xml_wrap(v)) for (k, v) in value.iteritems()
)
if type(value) is str:
return Binary(value)
if type(value) is Decimal:
# transfer Decimal as a string
return unicode(value)
if isinstance(value, (int, long)) and (value < MININT or value > MAXINT):
return unicode(value)
if isinstance(value, DN):
return str(value)
assert type(value) in (unicode, int, long, float, bool, NoneType)
return value
def xml_unwrap(value, encoding='UTF-8'):
"""
Unwrap all ``xmlrpc.Binary``, decode all ``str`` into ``unicode``.
When decoding data from an XML-RPC packet, the following transformations
occur:
* The binary payloads of all ``xmlrpclib.Binary`` instances are
returned as ``str`` instances.
* All ``str`` instances are treated as UTF-8 encoded Unicode strings.
They are decoded and the resulting ``unicode`` instance is returned.
Also see `xml_wrap()`.
:param value: The value to unwrap.
:param encoding: The Unicode encoding to use (defaults to ``'UTF-8'``).
"""
if type(value) in (list, tuple):
return tuple(xml_unwrap(v, encoding) for v in value)
if type(value) is dict:
return dict(
(k, xml_unwrap(v, encoding)) for (k, v) in value.iteritems()
)
if type(value) is str:
return value.decode(encoding)
if isinstance(value, Binary):
assert type(value.data) is str
return value.data
assert type(value) in (unicode, int, float, bool, NoneType)
return value
def xml_dumps(params, methodname=None, methodresponse=False, encoding='UTF-8'):
"""
Encode an XML-RPC data packet, transparently wraping ``params``.
This function will wrap ``params`` using `xml_wrap()` and will
then encode the XML-RPC data packet using ``xmlrpclib.dumps()`` (from the
Python standard library).
For documentation on the ``xmlrpclib.dumps()`` function, see:
http://docs.python.org/library/xmlrpclib.html#convenience-functions
Also see `xml_loads()`.
:param params: A ``tuple`` or an ``xmlrpclib.Fault`` instance.
:param methodname: The name of the method to call if this is a request.
:param methodresponse: Set this to ``True`` if this is a response.
:param encoding: The Unicode encoding to use (defaults to ``'UTF-8'``).
"""
if type(params) is tuple:
params = xml_wrap(params)
else:
assert isinstance(params, Fault)
return dumps(params,
methodname=methodname,
methodresponse=methodresponse,
encoding=encoding,
allow_none=True,
)
def decode_fault(e, encoding='UTF-8'):
assert isinstance(e, Fault)
if type(e.faultString) is str:
return Fault(e.faultCode, e.faultString.decode(encoding))
return e
def xml_loads(data, encoding='UTF-8'):
"""
Decode the XML-RPC packet in ``data``, transparently unwrapping its params.
This function will decode the XML-RPC packet in ``data`` using
``xmlrpclib.loads()`` (from the Python standard library). If ``data``
contains a fault, ``xmlrpclib.loads()`` will itself raise an
``xmlrpclib.Fault`` exception.
Assuming an exception is not raised, this function will then unwrap the
params in ``data`` using `xml_unwrap()`. Finally, a
``(params, methodname)`` tuple is returned containing the unwrapped params
and the name of the method being called. If the packet contains no method
name, ``methodname`` will be ``None``.
For documentation on the ``xmlrpclib.loads()`` function, see:
http://docs.python.org/library/xmlrpclib.html#convenience-functions
Also see `xml_dumps()`.
:param data: The XML-RPC packet to decode.
"""
try:
(params, method) = loads(data)
return (xml_unwrap(params), method)
except Fault, e:
raise decode_fault(e)
class LanguageAwareTransport(Transport):
"""Transport sending Accept-Language header"""
def get_host_info(self, host):
(host, extra_headers, x509) = Transport.get_host_info(self, host)
try:
lang = locale.setlocale(locale.LC_ALL, '').split('.')[0].lower()
except locale.Error:
# fallback to default locale
lang = 'en_us'
if not isinstance(extra_headers, list):
extra_headers = []
extra_headers.append(
('Accept-Language', lang.replace('_', '-'))
)
extra_headers.append(
('Referer', 'https://%s/ipa/xml' % str(host))
)
return (host, extra_headers, x509)
class SSLTransport(LanguageAwareTransport):
"""Handles an HTTPS transaction to an XML-RPC server."""
def __nss_initialized(self, dbdir):
"""
If there is another connections open it may have already
initialized NSS. This is likely to lead to an NSS shutdown
failure. One way to mitigate this is to tell NSS to not
initialize if it has already been done in another open connection.
Returns True if another connection is using the same db.
"""
for value in context.__dict__.values():
if not isinstance(value, Connection):
continue
if not isinstance(value.conn._ServerProxy__transport, SSLTransport):
continue
if hasattr(value.conn._ServerProxy__transport, 'dbdir') and \
value.conn._ServerProxy__transport.dbdir == dbdir:
return True
return False
def make_connection(self, host):
host, self._extra_headers, x509 = self.get_host_info(host)
# Python 2.7 changed the internal class used in xmlrpclib from
# HTTP to HTTPConnection. We need to use the proper subclass
# If we an existing connection exists using the same NSS database
# there is no need to re-initialize. Pass thsi into the NSS
# connection creator.
if sys.version_info >= (2, 7):
if self._connection and host == self._connection[0]:
return self._connection[1]
dbdir = '/etc/pki/nssdb'
no_init = self.__nss_initialized(dbdir)
if sys.version_info < (2, 7):
conn = NSSHTTPS(host, 443, dbdir=dbdir, no_init=no_init)
else:
conn = NSSConnection(host, 443, dbdir=dbdir, no_init=no_init)
self.dbdir=dbdir
conn.connect()
if sys.version_info < (2, 7):
return conn
else:
self._connection = host, conn
return self._connection[1]
class KerbTransport(SSLTransport):
"""
Handles Kerberos Negotiation authentication to an XML-RPC server.
"""
flags = kerberos.GSS_C_MUTUAL_FLAG | kerberos.GSS_C_SEQUENCE_FLAG
def _handle_exception(self, e, service=None):
(major, minor) = ipautil.get_gsserror(e)
if minor[1] == KRB5KDC_ERR_S_PRINCIPAL_UNKNOWN:
raise errors.ServiceError(service=service)
elif minor[1] == KRB5_FCC_NOFILE:
raise errors.NoCCacheError()
elif minor[1] == KRB5KRB_AP_ERR_TKT_EXPIRED:
raise errors.TicketExpired()
elif minor[1] == KRB5_FCC_PERM:
raise errors.BadCCachePerms()
elif minor[1] == KRB5_CC_FORMAT:
raise errors.BadCCacheFormat()
elif minor[1] == KRB5_REALM_CANT_RESOLVE:
raise errors.CannotResolveKDC()
else:
raise errors.KerberosError(major=major, minor=minor)
def get_host_info(self, host):
"""
Two things can happen here. If we have a session we will add
a cookie for that. If not we will set an Authorization header.
"""
(host, extra_headers, x509) = SSLTransport.get_host_info(self, host)
if not isinstance(extra_headers, list):
extra_headers = []
session_data = getattr(context, 'session_data', None)
if session_data:
extra_headers.append(('Cookie', session_data))
return (host, extra_headers, x509)
# Set the remote host principal
service = "HTTP@" + host.split(':')[0]
try:
(rc, vc) = kerberos.authGSSClientInit(service, self.flags)
except kerberos.GSSError, e:
self._handle_exception(e)
try:
kerberos.authGSSClientStep(vc, "")
except kerberos.GSSError, e:
self._handle_exception(e, service=service)
for (h, v) in extra_headers:
if h == 'Authorization':
extra_headers.remove((h, v))
break
extra_headers.append(
('Authorization', 'negotiate %s' % kerberos.authGSSClientResponse(vc))
)
return (host, extra_headers, x509)
def single_request(self, host, handler, request_body, verbose=0):
try:
return SSLTransport.single_request(self, host, handler, request_body, verbose)
finally:
self.close()
def parse_response(self, response):
session_cookie = response.getheader('Set-Cookie')
if session_cookie:
principal = getattr(context, 'principal', None)
try:
kernel_keyring.update_key(COOKIE_NAME % principal, session_cookie)
except ValueError, e:
# Not fatal, we just can't use the session cookie we were
# sent.
pass
return SSLTransport.parse_response(self, response)
class DelegatedKerbTransport(KerbTransport):
"""
Handles Kerberos Negotiation authentication and TGT delegation to an
XML-RPC server.
"""
flags = kerberos.GSS_C_DELEG_FLAG | kerberos.GSS_C_MUTUAL_FLAG | \
kerberos.GSS_C_SEQUENCE_FLAG
class xmlclient(Connectible):
"""
Forwarding backend plugin for XML-RPC client.
Also see the `ipaserver.rpcserver.xmlserver` plugin.
"""
def __init__(self):
super(xmlclient, self).__init__()
self.__errors = dict((e.errno, e) for e in public_errors)
def reconstruct_url(self):
"""
The URL directly isn't stored in the ServerProxy. We can't store
it in the connection object itself but we can reconstruct it
from the ServerProxy.
"""
if not hasattr(self.conn, '_ServerProxy__transport'):
return None
if (isinstance(self.conn._ServerProxy__transport, KerbTransport) or
isinstance(self.conn._ServerProxy__transport, DelegatedKerbTransport)):
scheme = "https"
else:
scheme = "http"
server = '%s://%s%s' % (scheme, ipautil.format_netloc(self.conn._ServerProxy__host), self.conn._ServerProxy__handler)
return server
def get_url_list(self, xmlrpc_uri):
"""
Create a list of urls consisting of the available IPA servers.
"""
# the configured URL defines what we use for the discovered servers
(scheme, netloc, path, params, query, fragment) = urlparse.urlparse(xmlrpc_uri)
servers = []
name = '_ldap._tcp.%s.' % self.env.domain
try:
answers = resolver.query(name, rdatatype.SRV)
except DNSException, e:
answers = []
for answer in answers:
server = str(answer.target).rstrip(".")
servers.append('https://%s%s' % (ipautil.format_netloc(server), path))
servers = list(set(servers))
# the list/set conversion won't preserve order so stick in the
# local config file version here.
cfg_server = xmlrpc_uri
if cfg_server in servers:
# make sure the configured master server is there just once and
# it is the first one
servers.remove(cfg_server)
servers.insert(0, cfg_server)
else:
servers.insert(0, cfg_server)
return servers
def create_connection(self, ccache=None, verbose=False, fallback=True,
delegate=False):
try:
session = False
session_data = None
xmlrpc_uri = self.env.xmlrpc_uri
principal = get_current_principal()
setattr(context, 'principal', principal)
# We have a session cookie, try using the session URI to see if it
# is still valid
if not delegate:
session_data = kernel_keyring.read_key(COOKIE_NAME % principal)
setattr(context, 'session_data', session_data)
(scheme, netloc, path, params, query, fragment) = urlparse.urlparse(self.env.xmlrpc_uri)
xmlrpc_uri = urlparse.urlunparse((scheme, netloc, '/ipa/session/xml', params, query, fragment))
session = True
except ValueError:
# No session key, do full Kerberos auth
pass
servers = self.get_url_list(xmlrpc_uri)
serverproxy = None
for server in servers:
kw = dict(allow_none=True, encoding='UTF-8')
kw['verbose'] = verbose
if server.startswith('https://'):
if delegate:
kw['transport'] = DelegatedKerbTransport()
else:
kw['transport'] = KerbTransport()
else:
kw['transport'] = LanguageAwareTransport()
self.log.info('trying %s' % server)
serverproxy = ServerProxy(server, **kw)
if len(servers) == 1:
# if we have only 1 server and then let the
# main requester handle any errors. This also means it
# must handle a 401 but we save a ping.
return serverproxy
try:
command = getattr(serverproxy, 'ping')
try:
response = command()
except Fault, e:
e = decode_fault(e)
if e.faultCode in self.__errors:
error = self.__errors[e.faultCode]
raise error(message=e.faultString)
else:
raise UnknownError(
code=e.faultCode,
error=e.faultString,
server=server,
)
# We don't care about the response, just that we got one
break
except KerberosError, krberr:
# kerberos error on one server is likely on all
raise errors.KerberosError(major=str(krberr), minor='')
except ProtocolError, e:
if session_data and e.errcode == 401:
# Unauthorized. Remove the session and try again.
delattr(context, 'session_data')
try:
kernel_keyring.del_key(COOKIE_NAME % principal)
except ValueError:
# This shouldn't happen if we have a session but
# it isn't fatal.
pass
return self.create_connection(ccache, verbose, fallback, delegate)
if not fallback:
raise
serverproxy = None
except Exception, e:
if not fallback:
raise
serverproxy = None
if serverproxy is None:
raise NetworkError(uri=_('any of the configured servers'),
error=', '.join(servers))
return serverproxy
def destroy_connection(self):
if sys.version_info >= (2, 7):
conn = getattr(context, self.id, None)
if conn is not None:
conn = conn.conn._ServerProxy__transport
conn.close()
def forward(self, name, *args, **kw):
"""
Forward call to command named ``name`` over XML-RPC.
This method will encode and forward an XML-RPC request, and will then
decode and return the corresponding XML-RPC response.
:param command: The name of the command being forwarded.
:param args: Positional arguments to pass to remote command.
:param kw: Keyword arguments to pass to remote command.
"""
if name not in self.Command:
raise ValueError(
'%s.forward(): %r not in api.Command' % (self.name, name)
)
server = self.reconstruct_url()
self.info('Forwarding %r to server %r', name, server)
command = getattr(self.conn, name)
params = [args, kw]
try:
response = command(*xml_wrap(params))
return xml_unwrap(response)
except Fault, e:
e = decode_fault(e)
self.debug('Caught fault %d from server %s: %s', e.faultCode,
server, e.faultString)
if e.faultCode in self.__errors:
error = self.__errors[e.faultCode]
raise error(message=e.faultString)
raise UnknownError(
code=e.faultCode,
error=e.faultString,
server=server,
)
except NSPRError, e:
raise NetworkError(uri=server, error=str(e))
except ProtocolError, e:
# By catching a 401 here we can detect the case where we have
# a single IPA server and the session is invalid. Otherwise
# we always have to do a ping().
session_data = getattr(context, 'session_data', None)
if session_data and e.errcode == 401:
# Unauthorized. Remove the session and try again.
delattr(context, 'session_data')
try:
principal = getattr(context, 'principal', None)
kernel_keyring.del_key(COOKIE_NAME % principal)
except ValueError:
# This shouldn't happen if we have a session but
# it isn't fatal.
pass
# Create a new serverproxy with the non-session URI. If there
# is an existing connection we need to save the NSS dbdir so
# we can skip an unnecessary NSS_Initialize() and avoid
# NSS_Shutdown issues.
serverproxy = self.create_connection(os.environ.get('KRB5CCNAME'), self.env.verbose, self.env.fallback, self.env.delegate)
dbdir = None
current_conn = getattr(context, self.id, None)
if current_conn is not None:
dbdir = getattr(current_conn.conn._ServerProxy__transport, 'dbdir', None)
if dbdir is not None:
self.debug('Using dbdir %s' % dbdir)
setattr(context, self.id, Connection(serverproxy, self.disconnect))
if dbdir is not None:
current_conn = getattr(context, self.id, None)
current_conn.conn._ServerProxy__transport.dbdir = dbdir
return self.forward(name, *args, **kw)
raise NetworkError(uri=server, error=e.errmsg)
except socket.error, e:
raise NetworkError(uri=server, error=str(e))
except (OverflowError, TypeError), e:
raise XMLRPCMarshallError(error=str(e))