# common.py - functions that are used by different modules
#
# Copyright (C) 2010, 2011, 2012 Arthur de Jong
#
# This library is free software; you can redistribute it and/or
# modify it under the terms of the GNU Lesser General Public
# License as published by the Free Software Foundation; either
# version 2.1 of the License, or (at your option) any later version.
#
# This library 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
# Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public
# License along with this library; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
# 02110-1301 USA
import logging
import sys
import ldap
import ldap.dn
from attmap import Attributes
import cache
import cfg
import constants
def isvalidname(name):
"""Checks to see if the specified name seems to be a valid user or group
name.
This test is based on the definition from POSIX (IEEE Std 1003.1, 2004,
3.426 User Name, 3.189 Group Name and 3.276 Portable Filename Character Set):
http://www.opengroup.org/onlinepubs/009695399/basedefs/xbd_chap03.html#tag_03_426
http://www.opengroup.org/onlinepubs/009695399/basedefs/xbd_chap03.html#tag_03_189
http://www.opengroup.org/onlinepubs/009695399/basedefs/xbd_chap03.html#tag_03_276
The standard defines user names valid if they contain characters from
the set [A-Za-z0-9._-] where the hyphen should not be used as first
character. As an extension this test allows some more characters."""
return bool(cfg.validnames.search(name))
def validate_name(name):
"""Checks to see if the specified name seems to be a valid user or group
name. See isvalidname()."""
if not cfg.validnames.search(name):
raise ValueError('%r: denied by validnames option' % name)
class Search(object):
"""
Class that performs a search. Subclasses are expected to define the actual
searches and should implement the following members:
case_sensitive - check that these attributes are present in the response
if they were in the request
case_insensitive - check that these attributes are present in the
response if they were in the request
limit_attributes - override response attributes with request attributes
(ensure that only one copy of the value is returned)
required - attributes that are required
canonical_first - search the DN for these attributes and ensure that
they are listed first in the attribute values
mk_filter() (optional) - function that returns the LDAP search filter
The module that contains the Request class can also contain the following
definitions:
attmap - an attribute mapping definition (using he Attributes class)
filter - an LDAP search filter
bases - search bases to be used, falls back to cfg.bases
scope - search scope, falls back to cfg.scope
"""
canonical_first = []
required = []
case_sensitive = []
case_insensitive = []
limit_attributes = []
# FIXME: figure out which of these arguments are actually needed
def __init__(self, conn, base=None, scope=None, filter=None, attributes=None,
parameters=None):
# load information from module that defines the class
self.conn = conn
module = sys.modules[self.__module__]
self.attmap = getattr(module, 'attmap', None)
self.filter = filter or getattr(module, 'filter', None)
self.parameters = parameters or {}
if base:
self.bases = [base]
else:
self.bases = getattr(module, 'bases', cfg.bases)
self.scope = scope or getattr(module, 'scope', cfg.scope)
self.attributes = attributes or self.attmap.attributes()
def __iter__(self):
return self.items()
def items(self):
"""Return the results from the search."""
filter = self.mk_filter()
for base in self.bases:
logging.debug('SEARCHING %s %s', base, filter)
try:
for entry in self.conn.search_s(base, self.scope, filter, self.attributes):
if entry[0]:
entry = self.handle_entry(entry[0], entry[1])
if entry:
yield entry
except ldap.NO_SUCH_OBJECT:
# FIXME: log message
pass
def escape(self, value):
"""Escape the provided value so it may be used in a search filter."""
return ldap.filter.escape_filter_chars(str(value))
def mk_filter(self):
"""Return the active search filter (based on the read parameters)."""
if self.parameters:
return '(&%s%s)' % (
self.filter,
''.join(self.attmap.mk_filter(attribute, value)
for attribute, value in self.parameters.items()))
return self.filter
def handle_entry(self, dn, attributes):
"""Handle an entry with the specified attributes, filtering it with
the request parameters where needed."""
# translate the attributes using the attribute mapping
if self.attmap:
attributes = self.attmap.translate(attributes)
# make sure value from DN is first value
for attr in self.canonical_first:
primary_value = self.attmap.get_rdn_value(dn, attr)
if primary_value:
values = attributes[attr]
if primary_value in values:
values.remove(primary_value)
attributes[attr] = [primary_value] + values
# check that these attributes have at least one value
for attr in self.required:
if not attributes.get(attr, None):
logging.warning('%s: %s: missing', dn, self.attmap[attr])
return
# check that requested attribute is present (case sensitive)
for attr in self.case_sensitive:
value = self.parameters.get(attr, None)
if value and str(value) not in attributes[attr]:
logging.debug('%s: %s: does not contain %r value', dn, self.attmap[attr], value)
return # not found, skip entry
# check that requested attribute is present (case insensitive)
for attr in self.case_insensitive:
value = self.parameters.get(attr, None)
if value and str(value).lower() not in (x.lower() for x in attributes[attr]):
logging.debug('%s: %s: does not contain %r value', dn, self.attmap[attr], value)
return # not found, skip entry
# limit attribute values to requested value
for attr in self.limit_attributes:
if attr in self.parameters:
attributes[attr] = [self.parameters[attr]]
# return the entry
return dn, attributes
class Request(object):
"""
Request handler class. Subclasses are expected to handle actual requests
and should implement the following members:
action - the NSLCD_ACTION_* action that should trigger this handler
read_parameters() - a function that reads the request parameters of the
request stream
write() - function that writes a single LDAP entry to the result stream
"""
def __init__(self, fp, conn, calleruid):
self.fp = fp
self.conn = conn
self.calleruid = calleruid
module = sys.modules[self.__module__]
self.search = getattr(module, 'Search', None)
if not hasattr(module, 'cache_obj'):
cache_cls = getattr(module, 'Cache', None)
module.cache_obj = cache_cls() if cache_cls else None
self.cache = module.cache_obj
def read_parameters(self, fp):
"""This method should read the parameters from ths stream and
store them in self."""
pass
def handle_request(self, parameters):
"""This method handles the request based on the parameters read
with read_parameters()."""
try:
with cache.con:
for dn, attributes in self.search(conn=self.conn, parameters=parameters):
for values in self.convert(dn, attributes, parameters):
self.fp.write_int32(constants.NSLCD_RESULT_BEGIN)
self.write(*values)
if self.cache:
self.cache.store(*values)
except ldap.SERVER_DOWN:
if self.cache:
logging.debug('read from cache')
# we assume server went down before writing any entries
for values in self.cache.retrieve(parameters):
self.fp.write_int32(constants.NSLCD_RESULT_BEGIN)
self.write(*values)
else:
raise
# write the final result code
self.fp.write_int32(constants.NSLCD_RESULT_END)
def __call__(self):
parameters = self.read_parameters(self.fp) or {}
logging.debug('%s(%r)', self.__class__.__name__, parameters)
self.fp.write_int32(constants.NSLCD_VERSION)
self.fp.write_int32(self.action)
self.handle_request(parameters)
def get_handlers(module):
"""Return a dictionary mapping actions to Request classes."""
import inspect
res = {}
if isinstance(module, basestring):
module = __import__(module, globals())
for name, cls in inspect.getmembers(module, inspect.isclass):
if issubclass(cls, Request) and hasattr(cls, 'action'):
res[cls.action] = cls
return res