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# Authors: Simo Sorce <ssorce@redhat.com>
#
# Copyright (C) 2007 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/>.
#
import socket
import os
import logging
import ipapython.dnsclient
import tempfile
import ldap
from ldap import LDAPError
from ipapython.ipautil import run, CalledProcessError
class IPADiscovery:
def __init__(self):
self.realm = None
self.domain = None
self.server = None
self.basedn = None
def __get_resolver_domains(self):
"""
Read /etc/resolv.conf and return all the domains found in domain and
search.
Returns a list
"""
domains = []
domain = None
try:
fp = open('/etc/resolv.conf', 'r')
lines = fp.readlines()
fp.close()
for line in lines:
if line.lower().startswith('domain'):
domain = line.split(None)[-1]
elif line.lower().startswith('search'):
domains = domains + line.split(None)[1:]
except:
pass
if domain and not domain in domains:
domains = [domain] + domains
return domains
def getServerName(self):
return self.server
def getDomainName(self):
return self.domain
def getRealmName(self):
return self.realm
def getBaseDN(self):
return self.basedn
def check_domain(self, domain):
"""
Given a domain search it for SRV records, breaking it down to search
all subdomains too.
Returns a tuple (server, domain) or (None,None) if a SRV record
isn't found.
"""
server = None
while not server:
logging.debug("[ipadnssearchldap("+domain+")]")
server = self.ipadnssearchldap(domain)
if server:
return (server, domain)
else:
p = domain.find(".")
if p == -1: #no ldap server found and last component of the domain already tested
return (None, None)
domain = domain[p+1:]
return (None, None)
def search(self, domain = "", server = ""):
hostname = ""
qname = ""
results = []
result = []
krbret = []
ldapret = []
if not server:
if not domain: #domain not provided do full DNS discovery
# get the local host name
hostname = socket.getfqdn()
if not hostname:
return -10 #bad host configuration
# first, check for an LDAP server for the local domain
p = hostname.find(".")
if p == -1: #no domain name
return -1
domain = hostname[p+1:]
# Get the list of domains from /etc/resolv.conf, we'll search
# them all. We search the domain of our hostname first though,
# even if that means searching it twice. This is to avoid the
# situation where domain isn't set in /etc/resolv.conf and
# the search list has the hostname domain not first. We could
# end up with the wrong SRV record.
domains = self.__get_resolver_domains()
domains = [domain] + domains
for domain in domains:
(server, domain) = self.check_domain(domain)
if server:
self.server = server
self.domain = domain
break
if not self.domain: #no ldap server found
return -1
else:
logging.debug("[ipadnssearchldap]")
self.server = self.ipadnssearchldap(domain)
if self.server:
self.domain = domain
else:
return -2 #no ldap server found
#search for kerberos TODO: move this after ipacheckldap()
logging.debug("[ipadnssearchkrb]")
krbret = self.ipadnssearchkrb(self.domain)
if not krbret:
return -3 #no krb server found
self.realm = krbret[0]
else: #server forced on us, this means DNS doesn't work :/
self.domain = domain
self.server = server
logging.debug("[ipacheckldap]")
# check ldap now
ldapret = self.ipacheckldap(self.server, self.realm)
if not ldapret:
return -4 # not an IPA server (or broken config)
self.server = ldapret[0]
self.realm = ldapret[1]
return 0
def ipacheckldap(self, thost, trealm):
lret = []
lres = []
lattr = ""
linfo = ""
lrealms = []
i = 0
# Get the CA certificate
try:
# Create TempDir
temp_ca_dir = tempfile.mkdtemp()
except OSError, e:
raise RuntimeError("Creating temporary directory failed: %s" % str(e))
try:
run(["/usr/bin/wget", "-O", "%s/ca.crt" % temp_ca_dir, "http://%s/ipa/config/ca.crt" % thost])
except CalledProcessError, e:
logging.debug('Retrieving CA from %s failed.\n%s' % (thost, str(e)))
return []
#now verify the server is really an IPA server
try:
logging.debug("Init ldap with: ldap://"+thost+":389")
lh = ldap.initialize("ldap://"+thost+":389")
ldap.set_option(ldap.OPT_X_TLS_REQUIRE_CERT, True)
ldap.set_option(ldap.OPT_X_TLS_CACERTFILE, "%s/ca.crt" % temp_ca_dir)
lh.set_option(ldap.OPT_PROTOCOL_VERSION, 3)
lh.set_option(ldap.OPT_X_TLS_DEMAND, True)
lh.start_tls_s()
lh.simple_bind_s("","")
logging.debug("Search rootdse")
lret = lh.search_s("", ldap.SCOPE_BASE, "(objectClass=*)")
for lattr in lret[0][1]:
if lattr.lower() == "namingcontexts":
self.basedn = lret[0][1][lattr][0]
logging.debug("Search for (info=*) in "+self.basedn+"(base)")
lret = lh.search_s(self.basedn, ldap.SCOPE_BASE, "(info=IPA*)")
if not lret:
return []
logging.debug("Found: "+str(lret))
for lattr in lret[0][1]:
if lattr.lower() == "info":
linfo = lret[0][1][lattr][0].lower()
break
if not linfo:
return []
#search and return known realms
logging.debug("Search for (objectClass=krbRealmContainer) in "+self.basedn+"(sub)")
lret = lh.search_s("cn=kerberos,"+self.basedn, ldap.SCOPE_SUBTREE, "(objectClass=krbRealmContainer)")
if not lret:
#something very wrong
return []
logging.debug("Found: "+str(lret))
for lres in lret:
for lattr in lres[1]:
if lattr.lower() == "cn":
lrealms.append(lres[1][lattr][0])
if trealm:
for r in lrealms:
if trealm == r:
return [thost, trealm]
# must match or something is very wrong
return []
else:
if len(lrealms) != 1:
#which one? we can't attach to a multi-realm server without DNS working
return []
else:
return [thost, lrealms[0]]
#we shouldn't get here
return []
except LDAPError, err:
if not isinstance(err, ldap.TIMEOUT):
logging.error("LDAP Error: %s: %s" %
(err.args[0]['desc'], err.args[0].get('info', '')))
else:
logging.error("LDAP Error: timeout")
return []
finally:
os.remove("%s/ca.crt" % temp_ca_dir)
os.removedirs(temp_ca_dir)
def ipadnssearchldap(self, tdomain):
servers = ""
rserver = ""
qname = "_ldap._tcp."+tdomain
# terminate the name
if not qname.endswith("."):
qname += "."
results = ipapython.dnsclient.query(qname, ipapython.dnsclient.DNS_C_IN, ipapython.dnsclient.DNS_T_SRV)
for result in results:
if result.dns_type == ipapython.dnsclient.DNS_T_SRV:
rserver = result.rdata.server.rstrip(".")
if result.rdata.port and result.rdata.port != 389:
rserver += ":" + str(result.rdata.port)
if servers:
servers += "," + rserver
else:
servers = rserver
break
return servers
def ipadnssearchkrb(self, tdomain):
realm = ""
kdc = ""
# now, check for a Kerberos realm the local host or domain is in
qname = "_kerberos." + tdomain
# terminate the name
if not qname.endswith("."):
qname += "."
results = ipapython.dnsclient.query(qname, ipapython.dnsclient.DNS_C_IN, ipapython.dnsclient.DNS_T_TXT)
for result in results:
if result.dns_type == ipapython.dnsclient.DNS_T_TXT:
realm = result.rdata.data
if realm:
break
if realm:
# now fetch server information for the realm
qname = "_kerberos._udp." + tdomain
# terminate the name
if not qname.endswith("."):
qname += "."
results = ipapython.dnsclient.query(qname, ipapython.dnsclient.DNS_C_IN, ipapython.dnsclient.DNS_T_SRV)
for result in results:
if result.dns_type == ipapython.dnsclient.DNS_T_SRV:
qname = result.rdata.server.rstrip(".")
if result.rdata.port and result.rdata.port != 88:
qname += ":" + str(result.rdata.port)
if kdc:
kdc += "," + qname
else:
kdc = qname
return [realm, kdc]
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