freeipa/ipalib/rpc.py
Rob Crittenden 17ba58aa4b Don't set dbdir in the connection until after the connection is created.
We were comparing the current connection with itself so were never
going to call nss_shutdown(). dbdir needs to be set after the connection
has been made.

This worked on single server installs because we don't do a ping so
NSS would never be pre-initialized. If multiple servers are available we
call ping() to find one that is up before submitting the request, this is
what would have pre-initialized NSS.

This was tripping up request-cert because it will intialize NSS with no DB
if it hasn't been initialized. We need to initialize it to validate the
CSR.

A non-working client was doing this when calling cert-request:
 - call load_certificate_request()
 - nss.nss_nodb_init()
 - load the CSR
 - create a connection, dbdir=/etc/pki/nssdb
 - the dbdir matches within the same connection, don't call nss_shutdown()
 - connect to remote server
 - fail, untrusted CA because we are still using db from nss_nodb_init.

Instead if we set dbdir afterward then this will properly be shutdown
and NSS re-initialized with correct dbdir.

https://fedorahosted.org/freeipa/ticket/2498
2012-03-13 22:42:12 -04:00

465 lines
17 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
import kerberos
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 ipapython import ipautil, dnsclient
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
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 type(value) is 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)
assert type(value) in (unicode, int, 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.
dbdir = '/etc/pki/nssdb'
no_init = self.__nss_initialized(dbdir)
(major, minor, micro, releaselevel, serial) = sys.version_info
if major == 2 and minor < 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()
return conn
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):
(host, extra_headers, x509) = SSLTransport.get_host_info(self, host)
# 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)
if not isinstance(extra_headers, list):
extra_headers = []
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)
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 type(self.conn._ServerProxy__transport) in (KerbTransport, 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):
"""
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(self.env.xmlrpc_uri)
servers = []
name = '_ldap._tcp.%s.' % self.env.domain
rs = dnsclient.query(name, dnsclient.DNS_C_IN, dnsclient.DNS_T_SRV)
for r in rs:
if r.dns_type == dnsclient.DNS_T_SRV:
rsrv = r.rdata.server.rstrip('.')
servers.append('https://%s%s' % (ipautil.format_netloc(rsrv), path))
servers = list(set(servers))
# the list/set conversion won't preserve order so stick in the
# local config file version here.
cfg_server = self.env.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):
servers = self.get_url_list()
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 or not fallback:
# if we have only 1 server to try then let the main
# requester handle any errors
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 Exception, e:
if not fallback:
raise e
serverproxy = None
if serverproxy is None:
raise NetworkError(uri='any of the configured servers', error=', '.join(servers))
return serverproxy
def destroy_connection(self):
pass
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:
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))