Tomas Babej
00a54b8b7f
Connection error message in ipa-client-install now warns the user about the need of opening of all the necessary ports for ipa-client enrollment when error that might have been caused by closed ports is encountered. Mentions the ports needed after the client enrollment as well. Improves other error messages during installation in various ways. https://fedorahosted.org/freeipa/ticket/2816
445 lines
16 KiB
Python
445 lines
16 KiB
Python
# Authors: Simo Sorce <ssorce@redhat.com>
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#
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# Copyright (C) 2007 Red Hat
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# see file 'COPYING' for use and warranty information
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#
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# This program is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation, either version 3 of the License, or
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# (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program. If not, see <http://www.gnu.org/licenses/>.
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#
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import socket
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import os
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from ipapython.ipa_log_manager import *
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import tempfile
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import ldap
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from ldap import LDAPError
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from dns import resolver, rdatatype
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from dns.exception import DNSException
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from ipapython.ipautil import run, CalledProcessError, valid_ip, get_ipa_basedn, \
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realm_to_suffix, format_netloc
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from ipapython.dn import DN
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NOT_FQDN = -1
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NO_LDAP_SERVER = -2
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REALM_NOT_FOUND = -3
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NOT_IPA_SERVER = -4
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NO_ACCESS_TO_LDAP = -5
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BAD_HOST_CONFIG = -10
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UNKNOWN_ERROR = -15
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error_names = {
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0: 'Success',
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NOT_FQDN: 'NOT_FQDN',
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NO_LDAP_SERVER: 'NO_LDAP_SERVER',
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REALM_NOT_FOUND: 'REALM_NOT_FOUND',
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NOT_IPA_SERVER: 'NOT_IPA_SERVER',
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NO_ACCESS_TO_LDAP: 'NO_ACCESS_TO_LDAP',
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BAD_HOST_CONFIG: 'BAD_HOST_CONFIG',
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UNKNOWN_ERROR: 'UNKNOWN_ERROR',
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}
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class IPADiscovery(object):
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def __init__(self):
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self.realm = None
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self.domain = None
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self.server = None
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self.basedn = None
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self.realm_source = None
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self.domain_source = None
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self.server_source = None
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self.basedn_source = None
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def __get_resolver_domains(self):
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"""
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Read /etc/resolv.conf and return all the domains found in domain and
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search.
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Returns a list of (domain, info) pairs. The info contains a reason why
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the domain is returned.
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"""
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domains = []
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domain = None
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try:
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fp = open('/etc/resolv.conf', 'r')
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lines = fp.readlines()
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fp.close()
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for line in lines:
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if line.lower().startswith('domain'):
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domain = (line.split()[-1],
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'local domain from /etc/resolv.conf')
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elif line.lower().startswith('search'):
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domains += [(d, 'search domain from /etc/resolv.conf') for
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d in line.split()[1:]]
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except:
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pass
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if domain:
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domains = [domain] + domains
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return domains
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def getServerName(self):
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return self.server
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def getDomainName(self):
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return self.domain
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def getRealmName(self):
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return self.realm
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def getKDCName(self):
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return self.kdc
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def getBaseDN(self):
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return self.basedn
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def check_domain(self, domain, tried, reason):
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"""
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Given a domain search it for SRV records, breaking it down to search
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all subdomains too.
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Returns a tuple (server, domain) or (None,None) if a SRV record
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isn't found.
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:param tried: A set of domains that were tried already
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:param reason: Reason this domain is searched (included in the log)
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"""
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server = None
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root_logger.debug('Start searching for LDAP SRV record in "%s" (%s) ' +
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'and its sub-domains', domain, reason)
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while not server:
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if domain in tried:
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root_logger.debug("Already searched %s; skipping", domain)
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break
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tried.add(domain)
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server = self.ipadns_search_srv(domain, '_ldap._tcp', 389)
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if server:
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return (server[0], domain)
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else:
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p = domain.find(".")
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if p == -1: #no ldap server found and last component of the domain already tested
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return (None, None)
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domain = domain[p+1:]
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return (None, None)
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def search(self, domain = "", server = "", hostname=None):
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root_logger.debug("[IPA Discovery]")
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root_logger.debug(
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'Starting IPA discovery with domain=%s, server=%s, hostname=%s',
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domain, server, hostname)
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if type(server) in (list, tuple):
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server = server[0]
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if not server:
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if not domain: #domain not provided do full DNS discovery
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# get the local host name
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if not hostname:
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hostname = socket.getfqdn()
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root_logger.debug('Hostname: %s', hostname)
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if not hostname:
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return BAD_HOST_CONFIG
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if valid_ip(hostname):
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return NOT_FQDN
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# first, check for an LDAP server for the local domain
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p = hostname.find(".")
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if p == -1: #no domain name
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return NOT_FQDN
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domain = hostname[p+1:]
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# Get the list of domains from /etc/resolv.conf, we'll search
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# them all. We search the domain of our hostname first though.
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# This is to avoid the situation where domain isn't set in
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# /etc/resolv.conf and the search list has the hostname domain
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# not first. We could end up with the wrong SRV record.
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domains = self.__get_resolver_domains()
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domains = [(domain, 'domain of the hostname')] + domains
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tried = set()
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for domain, reason in domains:
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server, domain = self.check_domain(domain, tried, reason)
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if server:
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self.server = server
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self.domain = domain
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self.server_source = self.domain_source = (
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'Discovered LDAP SRV records from %s (%s)' %
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(domain, reason))
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break
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if not self.domain: #no ldap server found
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root_logger.debug('No LDAP server found')
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return NO_LDAP_SERVER
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else:
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root_logger.debug("Search for LDAP SRV record in %s", domain)
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server = self.ipadns_search_srv(domain, '_ldap._tcp', 389)
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if server:
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self.server = server[0]
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self.domain = domain
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self.server_source = self.domain_source = (
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'Discovered LDAP SRV records from %s' % domain)
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else:
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self.server = None
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root_logger.debug('No LDAP server found')
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return NO_LDAP_SERVER
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else:
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root_logger.debug("Server and domain forced")
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self.domain = domain
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self.server = server
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self.domain_source = self.server_source = 'Forced'
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#search for kerberos
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root_logger.debug("[Kerberos realm search]")
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krb_realm, kdc = self.ipadnssearchkrb(self.domain)
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if not server and not krb_realm:
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return REALM_NOT_FOUND
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self.realm = krb_realm
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self.kdc = kdc
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self.realm_source = self.kdc_source = (
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'Discovered Kerberos DNS records from %s' % self.domain)
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root_logger.debug("[LDAP server check]")
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root_logger.debug('Verifying that %s (realm %s) is an IPA server',
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self.server, self.realm)
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# We may have received multiple servers corresponding to the domain
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# Iterate through all of those to check if it is IPA LDAP server
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ldapret = [NOT_IPA_SERVER]
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ldapaccess = True
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if self.server:
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# check ldap now
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ldapret = self.ipacheckldap(self.server, self.realm)
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if ldapret[0] == 0:
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self.server = ldapret[1]
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self.realm = ldapret[2]
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self.server_source = self.realm_source = (
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'Discovered from LDAP DNS records in %s' % self.server)
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elif ldapret[0] == NO_ACCESS_TO_LDAP:
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ldapaccess = False
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# If one of LDAP servers checked rejects access (maybe anonymous
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# bind is disabled), assume realm and basedn generated off domain.
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# Note that in case ldapret[0] == 0 and ldapaccess == False (one of
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# servers didn't provide access but another one succeeded), self.realm
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# will be set already to a proper value above, self.basdn will be
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# initialized during the LDAP check itself and we'll skip these two checks.
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if not ldapaccess and self.realm is None:
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# Assume realm is the same as domain.upper()
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self.realm = self.domain.upper()
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self.realm_source = 'Assumed same as domain'
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root_logger.debug(
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"Assuming realm is the same as domain: %s", self.realm)
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if not ldapaccess and self.basedn is None:
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# Generate suffix from realm
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self.basedn = realm_to_suffix(self.realm)
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self.basedn_source = 'Generated from Kerberos realm'
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root_logger.debug("Generated basedn from realm: %s" % self.basedn)
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root_logger.debug(
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"Discovery result: %s; server=%s, domain=%s, kdc=%s, basedn=%s",
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error_names.get(ldapret[0], ldapret[0]),
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self.server, self.domain, self.kdc, self.basedn)
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return ldapret[0]
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def ipacheckldap(self, thost, trealm):
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"""
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Given a host and kerberos realm verify that it is an IPA LDAP
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server hosting the realm. The connection is an SSL connection
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so the remote IPA CA cert must be available at
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http://HOST/ipa/config/ca.crt
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Returns a list [errno, host, realm] or an empty list on error.
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Errno is an error number:
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0 means all ok
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1 means we could not check the info in LDAP (may happend when
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anonymous binds are disabled)
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2 means the server is certainly not an IPA server
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"""
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lrealms = []
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i = 0
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# Get the CA certificate
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try:
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# Create TempDir
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temp_ca_dir = tempfile.mkdtemp()
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except OSError, e:
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raise RuntimeError("Creating temporary directory failed: %s" % str(e))
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try:
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run(["/usr/bin/wget", "-O", "%s/ca.crt" % temp_ca_dir, "-T", "15", "-t", "2",
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"http://%s/ipa/config/ca.crt" % format_netloc(thost)])
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except CalledProcessError, e:
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root_logger.error('Retrieving CA from %s failed', thost)
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root_logger.debug('Retrieving CA from %s failed: %s', thost, str(e))
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return [NOT_IPA_SERVER]
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#now verify the server is really an IPA server
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try:
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ldap_url = "ldap://" + format_netloc(thost, 389)
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root_logger.debug("Init LDAP connection with: %s", ldap_url)
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lh = ldap.initialize(ldap_url)
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ldap.set_option(ldap.OPT_X_TLS_REQUIRE_CERT, True)
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ldap.set_option(ldap.OPT_X_TLS_CACERTFILE, "%s/ca.crt" % temp_ca_dir)
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lh.set_option(ldap.OPT_PROTOCOL_VERSION, 3)
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lh.set_option(ldap.OPT_X_TLS_DEMAND, True)
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lh.start_tls_s()
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lh.simple_bind_s("","")
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# get IPA base DN
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root_logger.debug("Search LDAP server for IPA base DN")
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basedn = get_ipa_basedn(lh)
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if basedn is None:
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root_logger.debug("The server is not an IPA server")
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return [NOT_IPA_SERVER]
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self.basedn = basedn
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self.basedn_source = 'From IPA server %s' % ldap_url
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#search and return known realms
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root_logger.debug(
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"Search for (objectClass=krbRealmContainer) in %s (sub)",
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self.basedn)
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lret = lh.search_s(str(DN(('cn', 'kerberos'), self.basedn)), ldap.SCOPE_SUBTREE, "(objectClass=krbRealmContainer)")
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if not lret:
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#something very wrong
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return [REALM_NOT_FOUND]
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for lres in lret:
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root_logger.debug("Found: %s", lres[0])
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for lattr in lres[1]:
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if lattr.lower() == "cn":
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lrealms.append(lres[1][lattr][0])
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if trealm:
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for r in lrealms:
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if trealm == r:
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return [0, thost, trealm]
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# must match or something is very wrong
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return [REALM_NOT_FOUND]
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else:
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if len(lrealms) != 1:
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#which one? we can't attach to a multi-realm server without DNS working
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return [REALM_NOT_FOUND]
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else:
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return [0, thost, lrealms[0]]
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#we shouldn't get here
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return [UNKNOWN_ERROR]
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except LDAPError, err:
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if isinstance(err, ldap.TIMEOUT):
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root_logger.error("LDAP Error: timeout")
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return [NO_LDAP_SERVER]
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if isinstance(err, ldap.INAPPROPRIATE_AUTH):
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root_logger.debug("LDAP Error: Anonymous acces not allowed")
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return [NO_ACCESS_TO_LDAP]
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root_logger.error("LDAP Error: %s: %s" %
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(err.args[0]['desc'], err.args[0].get('info', '')))
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return [UNKNOWN_ERROR]
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finally:
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os.remove("%s/ca.crt" % temp_ca_dir)
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os.rmdir(temp_ca_dir)
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def ipadns_search_srv(self, domain, srv_record_name, default_port,
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break_on_first=True):
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"""
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Search for SRV records in given domain. When no record is found,
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en empty list is returned
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:param domain: Search domain name
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:param srv_record_name: SRV record name, e.g. "_ldap._tcp"
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:param default_port: When default_port is not None, it is being
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checked with the port in SRV record and if they don't
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match, the port from SRV record is appended to
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found hostname in this format: "hostname:port"
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:param break_on_first: break on the first find and return just one
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entry
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"""
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servers = []
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qname = '%s.%s' % (srv_record_name, domain)
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root_logger.debug("Search DNS for SRV record of %s", qname)
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try:
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answers = resolver.query(qname, rdatatype.SRV)
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except DNSException, e:
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root_logger.debug("DNS record not found: %s", e.__class__.__name__)
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answers = []
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for answer in answers:
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root_logger.debug("DNS record found: %s", answer)
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server = str(answer.target).rstrip(".")
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if not server:
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root_logger.debug("Cannot parse the hostname from SRV record: %s", answer)
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continue
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if default_port is not None and answer.port != default_port:
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server = "%s:%s" % (server, str(answer.port))
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servers.append(server)
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if break_on_first:
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break
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return servers
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def ipadnssearchkrb(self, tdomain):
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realm = None
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kdc = None
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# now, check for a Kerberos realm the local host or domain is in
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qname = "_kerberos." + tdomain
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root_logger.debug("Search DNS for TXT record of %s", qname)
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try:
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answers = resolver.query(qname, rdatatype.TXT)
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except DNSException, e:
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root_logger.debug("DNS record not found: %s", e.__class__.__name__)
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answers = []
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for answer in answers:
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root_logger.debug("DNS record found: %s", answer)
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if answer.strings:
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realm = answer.strings[0]
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if realm:
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break
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if realm:
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# now fetch server information for the realm
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domain = realm.lower()
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kdc = self.ipadns_search_srv(domain, '_kerberos._udp', 88,
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break_on_first=False)
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if not kdc:
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root_logger.debug("SRV record for KDC not found! Realm: %s, SRV record: %s" % (realm, qname))
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kdc = None
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kdc = ','.join(kdc)
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return realm, kdc
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