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'''This module manages ssh key files for bcfg2'''
__revision__ = '$Revision$'
import binascii, difflib, os, socket, xml.sax.saxutils
import Bcfg2.Server.Plugin
def update_file(path, diff):
'''Update file at path using diff'''
newdata = '\n'.join(difflib.restore(diff.split('\n'), 1))
print "writing file, %s" % path
open(path, 'w').write(newdata)
class SSHbase(Bcfg2.Server.Plugin.Plugin, Bcfg2.Server.Plugin.DirectoryBacked):
'''The sshbase generator manages ssh host keys (both v1 and v2)
for hosts. It also manages the ssh_known_hosts file. It can
integrate host keys from other management domains and similarly
export its keys. The repository contains files in the following
formats:
ssh_host_key.H_(hostname) -> the v1 host private key for
(hostname)
ssh_host_key.pub.H_(hostname) -> the v1 host public key
for (hostname)
ssh_host_(dr)sa_key.H_(hostname) -> the v2 ssh host
private key for (hostname)
ssh_host_(dr)sa_key.pub.H_(hostname) -> the v2 ssh host
public key for (hostname)
ssh_known_hosts -> the current known hosts file. this
is regenerated each time a new key is generated.
'''
__name__ = 'SSHbase'
__version__ = '$Id$'
__author__ = 'bcfg-dev@mcs.anl.gov'
pubkeys = ["ssh_host_dsa_key.pub.H_%s",
"ssh_host_rsa_key.pub.H_%s", "ssh_host_key.pub.H_%s"]
hostkeys = ["ssh_host_dsa_key.H_%s",
"ssh_host_rsa_key.H_%s", "ssh_host_key.H_%s"]
keypatterns = ['ssh_host_dsa_key', 'ssh_host_rsa_key', 'ssh_host_key',
'ssh_host_dsa_key.pub', 'ssh_host_rsa_key.pub', 'ssh_host_key.pub']
def __init__(self, core, datastore):
Bcfg2.Server.Plugin.Plugin.__init__(self, core, datastore)
try:
Bcfg2.Server.Plugin.DirectoryBacked.__init__(self, self.data, self.core.fam)
except OSError, ioerr:
self.logger.error("Failed to load SSHbase repository from %s" % (self.data))
self.logger.error(ioerr)
raise Bcfg2.Server.Plugin.PluginInitError
self.Entries = {'ConfigFile':
{'/etc/ssh/ssh_known_hosts':self.build_skn,
'/etc/ssh/ssh_host_dsa_key':self.build_hk,
'/etc/ssh/ssh_host_rsa_key':self.build_hk,
'/etc/ssh/ssh_host_dsa_key.pub':self.build_hk,
'/etc/ssh/ssh_host_rsa_key.pub':self.build_hk,
'/etc/ssh/ssh_host_key':self.build_hk,
'/etc/ssh/ssh_host_key.pub':self.build_hk}}
self.ipcache = {}
self.__rmi__ = ['GetPubKeys']
def HandleEvent(self, event=None):
'''Local event handler that does skn regen on pubkey change'''
Bcfg2.Server.Plugin.DirectoryBacked.HandleEvent(self, event)
if (len(self.entries.keys())) > (0.90 * len(os.listdir(self.data))) and \
event and '_key.pub.H_' in event.filename:
self.cache_skn()
elif (len(self.entries.keys())) > (0.90 * len(os.listdir(self.data))) and \
not hasattr(self, 'static_skn'):
self.cache_skn()
def HandlesEntry(self, entry):
'''Handle key entries dynamically'''
return entry.tag == 'ConfigFile' and \
[fpat for fpat in self.keypatterns if entry.get('name').endswith(fpat)]
def HandleEntry(self, entry, metadata):
'''Bind key data'''
return self.build_hk(entry, metadata)
def GetPubKeys(self, _):
'''Export public key data'''
if not hasattr(self, 'static_skn'):
self.cache_skn()
return self.static_skn
def get_ipcache_entry(self, client):
'''build a cache of dns results'''
if self.ipcache.has_key(client):
if self.ipcache[client]:
return self.ipcache[client]
else:
raise socket.gaierror
else:
# need to add entry
try:
ipaddr = socket.gethostbyname(client)
self.ipcache[client] = (ipaddr, client)
return (ipaddr, client)
except socket.gaierror:
ipaddr = os.popen("getent hosts %s" % client).read().strip().split()
if ipaddr:
self.ipcache[client] = (ipaddr, client)
return (ipaddr, client)
self.ipcache[client] = False
self.logger.error("Failed to find IP address for %s" % client)
raise socket.gaierror
def cache_skn(self):
'''build memory cache of the ssh known hosts file'''
self.static_skn = ''
pubkeys = [pubk for pubk in self.entries.keys() if pubk.find('.pub.H_') != -1]
pubkeys.sort()
for pubkey in pubkeys:
hostname = pubkey.split('H_')[1]
try:
(ipaddr, fqdn) = self.get_ipcache_entry(hostname)
except socket.gaierror:
continue
shortname = hostname.split('.')[0]
self.static_skn += "%s,%s,%s %s" % (shortname, fqdn, ipaddr,
self.entries[pubkey].data)
def build_skn(self, entry, metadata):
'''This function builds builds a host specific known_hosts file'''
client = metadata.hostname
entry.text = self.static_skn
hostkeys = [keytmpl % client for keytmpl in self.pubkeys \
if self.entries.has_key(keytmpl % client)]
hostkeys.sort()
for hostkey in hostkeys:
entry.text += "localhost,localhost.localdomain,127.0.0.1 %s" % (
self.entries[hostkey].data)
permdata = {'owner':'root', 'group':'root', 'perms':'0644'}
[entry.attrib.__setitem__(key, permdata[key]) for key in permdata]
def build_hk(self, entry, metadata):
'''This binds host key data into entries'''
client = metadata.hostname
filename = "%s.H_%s" % (entry.get('name').split('/')[-1], client)
if filename not in self.entries.keys():
self.GenerateHostKeys(client)
if not self.entries.has_key(filename):
self.logger.error("%s still not registered" % filename)
raise Bcfg2.Server.Plugin.PluginExecutionError
keydata = self.entries[filename].data
permdata = {'owner':'root', 'group':'root'}
permdata['perms'] = '0600'
if entry.get('name')[-4:] == '.pub':
permdata['perms'] = '0644'
[entry.attrib.__setitem__(key, permdata[key]) for key in permdata]
if "ssh_host_key.H_" == filename[:15]:
entry.attrib['encoding'] = 'base64'
entry.text = binascii.b2a_base64(keydata)
else:
entry.text = keydata
def GenerateHostKeys(self, client):
'''Generate new host keys for client'''
keylist = [keytmpl % client for keytmpl in self.hostkeys]
for hostkey in keylist:
if 'ssh_host_rsa_key.H_' == hostkey[:19]:
keytype = 'rsa'
elif 'ssh_host_dsa_key.H_' == hostkey[:19]:
keytype = 'dsa'
else:
keytype = 'rsa1'
if hostkey not in self.entries.keys():
fileloc = "%s/%s" % (self.data, hostkey)
publoc = self.data + '/' + ".".join([hostkey.split('.')[0]]+['pub', "H_%s" % client])
temploc = "/tmp/%s" % hostkey
os.system('ssh-keygen -q -f %s -N "" -t %s -C root@%s < /dev/null' %
(temploc, keytype, client))
open(fileloc, 'w').write(open(temploc).read())
open(publoc, 'w').write(open("%s.pub" % temploc).read())
self.AddEntry(hostkey)
self.AddEntry(".".join([hostkey.split('.')[0]]+['pub', "H_%s" % client]))
try:
os.unlink(temploc)
os.unlink("%s.pub" % temploc)
except OSError:
self.logger.error("Failed to unlink temporary ssh keys")
def AcceptEntry(self, meta, _, entry_name, diff, fulldata, metadata_updates={}):
'''per-plugin bcfg2-admin pull support'''
filename = "%s/%s.H_%s" % (self.data, entry_name.split('/')[-1],
meta.hostname)
print "This file will be installed as file %s" % filename
if raw_input("Should it be installed? (N/y): ") in ['Y', 'y']:
print "writing file, %s" % filename
if fulldata:
newdata = fulldata
else:
newdata = '\n'.join(difflib.restore(diff.split('\n'), 1))
open(filename, 'w').write(newdata)
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