'''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(xml.sax.saxutils.unescape(diff).split('\n'), 1)) print "writing file, %s" % path open(path, 'w').write(newdata) class SSHbase(Bcfg2.Server.Plugin.Plugin): '''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: self.repository = Bcfg2.Server.Plugin.DirectoryBacked(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 try: prefix = open("%s/prefix" % (self.data)).read().strip() except IOError: prefix = '' self.Entries = {'ConfigFile': {prefix + '/etc/ssh/ssh_known_hosts':self.build_skn, prefix + '/etc/ssh/ssh_host_dsa_key':self.build_hk, prefix + '/etc/ssh/ssh_host_rsa_key':self.build_hk, prefix + '/etc/ssh/ssh_host_dsa_key.pub':self.build_hk, prefix + '/etc/ssh/ssh_host_rsa_key.pub':self.build_hk, prefix + '/etc/ssh/ssh_host_key':self.build_hk, prefix + '/etc/ssh/ssh_host_key.pub':self.build_hk}} self.ipcache = {} self.__rmi__ = ['GetPubKeys'] 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): return self.ipcache[client] 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.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.repository.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.repository.entries[pubkey].data) def build_skn(self, entry, metadata): '''This function builds builds a host specific known_hosts file''' client = metadata.hostname if not hasattr(self, 'static_skn'): self.cache_skn() entry.text = self.static_skn hostkeys = [keytmpl % client for keytmpl in self.pubkeys \ if self.repository.entries.has_key(keytmpl % client)] hostkeys.sort() for hostkey in hostkeys: entry.text += "localhost,localhost.localdomain,127.0.0.1 %s" % ( self.repository.entries[hostkey].data) permdata = {'owner':'root', 'group':'0', '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.repository.entries.keys(): self.GenerateHostKeys(client) if hasattr(self, 'static_skn'): del self.static_skn if not self.repository.entries.has_key(filename): self.logger.error("%s still not registered" % filename) raise Bcfg2.Server.Plugin.PluginExecutionError keydata = self.repository.entries[filename].data permdata = {'owner':'root', 'group':'0'} 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.repository.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.repository.AddEntry(hostkey) self.repository.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): '''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 'Yy': update_file(filename, diff)