trAvis - MANAGER

Edit File: imapserver.py

# IMAP server support # Copyright (C) 2002 - 2011 John Goerzen & contributors # # 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 2 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, write to the Free Software # Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA from threading import Lock, BoundedSemaphore, Thread, Event, currentThread import hmac import socket import base64 import json import urllib import socket import time import errno from sys import exc_info from socket import gaierror from ssl import SSLError, cert_time_to_seconds from offlineimap import imaplibutil, imaputil, threadutil, OfflineImapError import offlineimap.accounts from offlineimap.ui import getglobalui try: # do we have a recent pykerberos? have_gss = False import kerberos if 'authGSSClientWrap' in dir(kerberos): have_gss = True except ImportError: pass class IMAPServer: """Initializes all variables from an IMAPRepository() instance Various functions, such as acquireconnection() return an IMAP4 object on which we can operate. Public instance variables are: self.: delim The server's folder delimiter. Only valid after acquireconnection() """ GSS_STATE_STEP = 0 GSS_STATE_WRAP = 1 def __init__(self, repos): self.ui = getglobalui() self.repos = repos self.config = repos.getconfig() self.preauth_tunnel = repos.getpreauthtunnel() self.transport_tunnel = repos.gettransporttunnel() if self.preauth_tunnel and self.transport_tunnel: raise OfflineImapError('%s: '% repos + 'you must enable precisely one ' 'type of tunnel (preauth or transport), ' 'not both', OfflineImapError.ERROR.REPO) self.tunnel = \ self.preauth_tunnel if self.preauth_tunnel \ else self.transport_tunnel self.username = \ None if self.preauth_tunnel else repos.getuser() self.user_identity = repos.get_remote_identity() self.authmechs = repos.get_auth_mechanisms() self.password = None self.passworderror = None self.goodpassword = None self.usessl = repos.getssl() self.useipv6 = repos.getipv6() if self.useipv6 == True: self.af = socket.AF_INET6 elif self.useipv6 == False: self.af = socket.AF_INET else: self.af = socket.AF_UNSPEC self.hostname = \ None if self.preauth_tunnel else repos.gethost() self.port = repos.getport() if self.port == None: self.port = 993 if self.usessl else 143 self.sslclientcert = repos.getsslclientcert() self.sslclientkey = repos.getsslclientkey() self.sslcacertfile = repos.getsslcacertfile() if self.sslcacertfile is None: self.__verifycert = None # disable cert verification self.fingerprint = repos.get_ssl_fingerprint() self.sslversion = repos.getsslversion() self.tlslevel = repos.gettlslevel() self.oauth2_refresh_token = repos.getoauth2_refresh_token() self.oauth2_access_token = repos.getoauth2_access_token() self.oauth2_client_id = repos.getoauth2_client_id() self.oauth2_client_secret = repos.getoauth2_client_secret() self.oauth2_request_url = repos.getoauth2_request_url() self.delim = None self.root = None self.maxconnections = repos.getmaxconnections() self.availableconnections = [] self.assignedconnections = [] self.lastowner = {} self.semaphore = BoundedSemaphore(self.maxconnections) self.connectionlock = Lock() self.reference = repos.getreference() self.idlefolders = repos.getidlefolders() self.gss_step = self.GSS_STATE_STEP self.gss_vc = None self.gssapi = False # In order to support proxy connection, we have to override the # default socket instance with our own socksified socket instance. # We add this option to bypass the GFW in China. _account_section = 'Account ' + self.repos.account.name if not self.config.has_option(_account_section, 'proxy'): self.proxied_socket = socket.socket else: proxy = self.config.get(_account_section, 'proxy') # Powered by PySocks. try: import socks proxy_type, host, port = proxy.split(":") port = int(port) socks.setdefaultproxy(getattr(socks, proxy_type), host, port) self.proxied_socket = socks.socksocket except ImportError: self.ui.warn("PySocks not installed, ignoring proxy option.") self.proxied_socket = socket.socket except (AttributeError, ValueError) as e: self.ui.warn("Bad proxy option %s for account %s: %s " "Ignoring proxy option."% (proxy, self.repos.account.name, e)) self.proxied_socket = socket.socket def __getpassword(self): """Returns the server password or None""" if self.goodpassword != None: # use cached good one first return self.goodpassword if self.password != None and self.passworderror == None: return self.password # non-failed preconfigured one # get 1) configured password first 2) fall back to asking via UI self.password = self.repos.getpassword() or \ self.ui.getpass(self.repos.getname(), self.config, self.passworderror) self.passworderror = None return self.password # XXX: is this function used anywhere? def getroot(self): """Returns this server's folder root. Can only be called after one or more calls to acquireconnection.""" return self.root def releaseconnection(self, connection, drop_conn=False): """Releases a connection, returning it to the pool. :param drop_conn: If True, the connection will be released and not be reused. This can be used to indicate broken connections.""" if connection is None: return #noop on bad connection self.connectionlock.acquire() self.assignedconnections.remove(connection) # Don't reuse broken connections if connection.Terminate or drop_conn: connection.logout() else: self.availableconnections.append(connection) self.connectionlock.release() self.semaphore.release() def __md5handler(self, response): challenge = response.strip() self.ui.debug('imap', '__md5handler: got challenge %s'% challenge) passwd = self.__getpassword() retval = self.username + ' ' + hmac.new(passwd, challenge).hexdigest() self.ui.debug('imap', '__md5handler: returning %s'% retval) return retval def __loginauth(self, imapobj): """ Basic authentication via LOGIN command.""" self.ui.debug('imap', 'Attempting IMAP LOGIN authentication') imapobj.login(self.username, self.__getpassword()) def __plainhandler(self, response): """Implements SASL PLAIN authentication, RFC 4616, http://tools.ietf.org/html/rfc4616""" authc = self.username passwd = self.__getpassword() authz = '' if self.user_identity != None: authz = self.user_identity NULL = u'\x00' retval = NULL.join((authz, authc, passwd)).encode('utf-8') logsafe_retval = NULL.join((authz, authc, "(passwd hidden for log)")).encode('utf-8') self.ui.debug('imap', '__plainhandler: returning %s' % logsafe_retval) return retval def __xoauth2handler(self, response): if self.oauth2_refresh_token is None and self.oauth2_access_token is None: return None if self.oauth2_access_token is None: # need to move these to config # generate new access token params = {} params['client_id'] = self.oauth2_client_id params['client_secret'] = self.oauth2_client_secret params['refresh_token'] = self.oauth2_refresh_token params['grant_type'] = 'refresh_token' self.ui.debug('imap', 'xoauth2handler: url "%s"' % self.oauth2_request_url) self.ui.debug('imap', 'xoauth2handler: params "%s"' % params) original_socket = socket.socket socket.socket = self.proxied_socket try: response = urllib.urlopen(self.oauth2_request_url, urllib.urlencode(params)).read() finally: socket.socket = original_socket resp = json.loads(response) self.ui.debug('imap', 'xoauth2handler: response "%s"' % resp) self.oauth2_access_token = resp['access_token'] self.ui.debug('imap', 'xoauth2handler: access_token "%s"' % self.oauth2_access_token) auth_string = 'user=%s\1auth=Bearer %s\1\1' % (self.username, self.oauth2_access_token) #auth_string = base64.b64encode(auth_string) self.ui.debug('imap', 'xoauth2handler: returning "%s"' % auth_string) return auth_string def __gssauth(self, response): data = base64.b64encode(response) try: if self.gss_step == self.GSS_STATE_STEP: if not self.gss_vc: rc, self.gss_vc = kerberos.authGSSClientInit( 'imap@' + self.hostname) response = kerberos.authGSSClientResponse(self.gss_vc) rc = kerberos.authGSSClientStep(self.gss_vc, data) if rc != kerberos.AUTH_GSS_CONTINUE: self.gss_step = self.GSS_STATE_WRAP elif self.gss_step == self.GSS_STATE_WRAP: rc = kerberos.authGSSClientUnwrap(self.gss_vc, data) response = kerberos.authGSSClientResponse(self.gss_vc) rc = kerberos.authGSSClientWrap( self.gss_vc, response, self.username) response = kerberos.authGSSClientResponse(self.gss_vc) except kerberos.GSSError as err: # Kerberos errored out on us, respond with None to cancel the # authentication self.ui.debug('imap', '%s: %s'% (err[0][0], err[1][0])) return None if not response: response = '' return base64.b64decode(response) def __start_tls(self, imapobj): if 'STARTTLS' in imapobj.capabilities and not self.usessl: self.ui.debug('imap', 'Using STARTTLS connection') try: imapobj.starttls() except imapobj.error as e: raise OfflineImapError("Failed to start " "TLS connection: %s"% str(e), OfflineImapError.ERROR.REPO, None, exc_info()[2]) ## All __authn_* procedures are helpers that do authentication. ## They are class methods that take one parameter, IMAP object. ## ## Each function should return True if authentication was ## successful and False if authentication wasn't even tried ## for some reason (but not when IMAP has no such authentication ## capability, calling code checks that). ## ## Functions can also raise exceptions; two types are special ## and will be handled by the calling code: ## ## - imapobj.error means that there was some error that ## comes from imaplib2; ## ## - OfflineImapError means that function detected some ## problem by itself. def __authn_gssapi(self, imapobj): if not have_gss: return False self.connectionlock.acquire() try: imapobj.authenticate('GSSAPI', self.__gssauth) return True except imapobj.error as e: self.gssapi = False raise else: self.gssapi = True kerberos.authGSSClientClean(self.gss_vc) self.gss_vc = None self.gss_step = self.GSS_STATE_STEP finally: self.connectionlock.release() def __authn_cram_md5(self, imapobj): imapobj.authenticate('CRAM-MD5', self.__md5handler) return True def __authn_plain(self, imapobj): imapobj.authenticate('PLAIN', self.__plainhandler) return True def __authn_xoauth2(self, imapobj): imapobj.authenticate('XOAUTH2', self.__xoauth2handler) return True def __authn_login(self, imapobj): # Use LOGIN command, unless LOGINDISABLED is advertized # (per RFC 2595) if 'LOGINDISABLED' in imapobj.capabilities: raise OfflineImapError("IMAP LOGIN is " "disabled by server. Need to use SSL?", OfflineImapError.ERROR.REPO) else: self.__loginauth(imapobj) return True def __authn_helper(self, imapobj): """Authentication machinery for self.acquireconnection(). Raises OfflineImapError() of type ERROR.REPO when there are either fatal problems or no authentications succeeded. If any authentication method succeeds, routine should exit: warnings for failed methods are to be produced in the respective except blocks.""" # Authentication routines, hash keyed by method name # with value that is a tuple with # - authentication function, # - tryTLS flag, # - check IMAP capability flag. auth_methods = { "GSSAPI": (self.__authn_gssapi, False, True), "CRAM-MD5": (self.__authn_cram_md5, True, True), "XOAUTH2": (self.__authn_xoauth2, True, True), "PLAIN": (self.__authn_plain, True, True), "LOGIN": (self.__authn_login, True, False), } # Stack stores pairs of (method name, exception) exc_stack = [] tried_to_authn = False tried_tls = False mechs = self.authmechs # GSSAPI must be tried first: we will probably go TLS after it # and GSSAPI mustn't be tunneled over TLS. if "GSSAPI" in mechs: mechs.remove("GSSAPI") mechs.insert(0, "GSSAPI") for m in mechs: if m not in auth_methods: raise Exception("Bad authentication method %s, " "please, file OfflineIMAP bug" % m) func, tryTLS, check_cap = auth_methods[m] # TLS must be initiated before checking capabilities: # they could have been changed after STARTTLS. if tryTLS and not tried_tls: tried_tls = True self.__start_tls(imapobj) if check_cap: cap = "AUTH=" + m if cap not in imapobj.capabilities: continue tried_to_authn = True self.ui.debug('imap', u'Attempting ' '%s authentication'% m) try: if func(imapobj): return except (imapobj.error, OfflineImapError) as e: self.ui.warn('%s authentication failed: %s'% (m, e)) exc_stack.append((m, e)) if len(exc_stack): msg = "\n\t".join(map( lambda x: ": ".join((x[0], str(x[1]))), exc_stack )) raise OfflineImapError("All authentication types " "failed:\n\t%s"% msg, OfflineImapError.ERROR.REPO) if not tried_to_authn: methods = ", ".join(map( lambda x: x[5:], filter(lambda x: x[0:5] == "AUTH=", imapobj.capabilities) )) raise OfflineImapError(u"Repository %s: no supported " "authentication mechanisms found; configured %s, " "server advertises %s"% (self.repos, ", ".join(self.authmechs), methods), OfflineImapError.ERROR.REPO) # XXX: move above, closer to releaseconnection() def acquireconnection(self): """Fetches a connection from the pool, making sure to create a new one if needed, to obey the maximum connection limits, etc. Opens a connection to the server and returns an appropriate object.""" self.semaphore.acquire() self.connectionlock.acquire() curThread = currentThread() imapobj = None if len(self.availableconnections): # One is available. # Try to find one that previously belonged to this thread # as an optimization. Start from the back since that's where # they're popped on. imapobj = None for i in range(len(self.availableconnections) - 1, -1, -1): tryobj = self.availableconnections[i] if self.lastowner[tryobj] == curThread.ident: imapobj = tryobj del(self.availableconnections[i]) break if not imapobj: imapobj = self.availableconnections[0] del(self.availableconnections[0]) self.assignedconnections.append(imapobj) self.lastowner[imapobj] = curThread.ident self.connectionlock.release() return imapobj self.connectionlock.release() # Release until need to modify data # Must be careful here that if we fail we should bail out gracefully # and release locks / threads so that the next attempt can try... success = 0 try: while not success: # Generate a new connection. if self.tunnel: self.ui.connecting('tunnel', self.tunnel) imapobj = imaplibutil.IMAP4_Tunnel( self.tunnel, timeout=socket.getdefaulttimeout(), use_socket=self.proxied_socket, ) success = 1 elif self.usessl: self.ui.connecting(self.hostname, self.port) imapobj = imaplibutil.WrappedIMAP4_SSL( self.hostname, self.port, self.sslclientkey, self.sslclientcert, self.sslcacertfile, self.__verifycert, self.sslversion, timeout=socket.getdefaulttimeout(), fingerprint=self.fingerprint, use_socket=self.proxied_socket, tls_level=self.tlslevel, af=self.af, ) else: self.ui.connecting(self.hostname, self.port) imapobj = imaplibutil.WrappedIMAP4( self.hostname, self.port, timeout=socket.getdefaulttimeout(), use_socket=self.proxied_socket, af=self.af, ) if not self.preauth_tunnel: try: self.__authn_helper(imapobj) self.goodpassword = self.password success = 1 except OfflineImapError as e: self.passworderror = str(e) raise # Enable compression if self.repos.getconfboolean('usecompression', 0): imapobj.enable_compression() # update capabilities after login, e.g. gmail serves different ones typ, dat = imapobj.capability() if dat != [None]: imapobj.capabilities = tuple(dat[-1].upper().split()) if self.delim == None: listres = imapobj.list(self.reference, '""')[1] if listres == [None] or listres == None: # Some buggy IMAP servers do not respond well to LIST "" "" # Work around them. listres = imapobj.list(self.reference, '"*"')[1] if listres == [None] or listres == None: # No Folders were returned. This occurs, e.g. if the # 'reference' prefix does not exist on the mail # server. Raise exception. err = "Server '%s' returned no folders in '%s'"% \ (self.repos.getname(), self.reference) self.ui.warn(err) raise Exception(err) self.delim, self.root = \ imaputil.imapsplit(listres[0])[1:] self.delim = imaputil.dequote(self.delim) self.root = imaputil.dequote(self.root) with self.connectionlock: self.assignedconnections.append(imapobj) self.lastowner[imapobj] = curThread.ident return imapobj except Exception as e: """If we are here then we did not succeed in getting a connection - we should clean up and then re-raise the error...""" self.semaphore.release() severity = OfflineImapError.ERROR.REPO if type(e) == gaierror: #DNS related errors. Abort Repo sync #TODO: special error msg for e.errno == 2 "Name or service not known"? reason = "Could not resolve name '%s' for repository "\ "'%s'. Make sure you have configured the ser"\ "ver name correctly and that you are online."%\ (self.hostname, self.repos) raise OfflineImapError(reason, severity), None, exc_info()[2] elif isinstance(e, SSLError) and e.errno == errno.EPERM: # SSL unknown protocol error # happens e.g. when connecting via SSL to a non-SSL service if self.port != 993: reason = "Could not connect via SSL to host '%s' and non-s"\ "tandard ssl port %d configured. Make sure you connect"\ " to the correct port."% (self.hostname, self.port) else: reason = "Unknown SSL protocol connecting to host '%s' for "\ "repository '%s'. OpenSSL responded:\n%s"\ % (self.hostname, self.repos, e) raise OfflineImapError(reason, severity), None, exc_info()[2] elif isinstance(e, socket.error) and e.args[0] == errno.ECONNREFUSED: # "Connection refused", can be a non-existing port, or an unauthorized # webproxy (open WLAN?) reason = "Connection to host '%s:%d' for repository '%s' was "\ "refused. Make sure you have the right host and port "\ "configured and that you are actually able to access the "\ "network."% (self.hostname, self.port, self.repos) raise OfflineImapError(reason, severity), None, exc_info()[2] # Could not acquire connection to the remote; # socket.error(last_error) raised if str(e)[:24] == "can't open socket; error": raise OfflineImapError("Could not connect to remote server '%s' "\ "for repository '%s'. Remote does not answer." % (self.hostname, self.repos), OfflineImapError.ERROR.REPO), None, exc_info()[2] else: # re-raise all other errors raise def connectionwait(self): """Waits until there is a connection available. Note that between the time that a connection becomes available and the time it is requested, another thread may have grabbed it. This function is mainly present as a way to avoid spawning thousands of threads to copy messages, then have them all wait for 3 available connections. It's OK if we have maxconnections + 1 or 2 threads, which is what this will help us do.""" self.semaphore.acquire() self.semaphore.release() def close(self): # Make sure I own all the semaphores. Let the threads finish # their stuff. This is a blocking method. with self.connectionlock: # first, wait till all connections had been released. # TODO: won't work IMHO, as releaseconnection() also # requires the connectionlock, leading to a potential # deadlock! Audit & check! threadutil.semaphorereset(self.semaphore, self.maxconnections) for imapobj in self.assignedconnections + self.availableconnections: imapobj.logout() self.assignedconnections = [] self.availableconnections = [] self.lastowner = {} # reset kerberos state self.gss_step = self.GSS_STATE_STEP self.gss_vc = None self.gssapi = False def keepalive(self, timeout, event): """Sends a NOOP to each connection recorded. It will wait a maximum of timeout seconds between doing this, and will continue to do so until the Event object as passed is true. This method is expected to be invoked in a separate thread, which should be join()'d after the event is set.""" self.ui.debug('imap', 'keepalive thread started') while not event.isSet(): self.connectionlock.acquire() numconnections = len(self.assignedconnections) + \ len(self.availableconnections) self.connectionlock.release() threads = [] for i in range(numconnections): self.ui.debug('imap', 'keepalive: processing connection %d of %d'% (i, numconnections)) if len(self.idlefolders) > i: # IDLE thread idler = IdleThread(self, self.idlefolders[i]) else: # NOOP thread idler = IdleThread(self) idler.start() threads.append(idler) self.ui.debug('imap', 'keepalive: waiting for timeout') event.wait(timeout) self.ui.debug('imap', 'keepalive: after wait') for idler in threads: # Make sure all the commands have completed. idler.stop() idler.join() self.ui.debug('imap', 'keepalive: all threads joined') self.ui.debug('imap', 'keepalive: event is set; exiting') return def __verifycert(self, cert, hostname): """Verify that cert (in socket.getpeercert() format) matches hostname. CRLs are not handled. Returns error message if any problems are found and None on success.""" errstr = "CA Cert verifying failed: " if not cert: return ('%s no certificate received'% errstr) dnsname = hostname.lower() certnames = [] # cert expired? notafter = cert.get('notAfter') if notafter: if time.time() >= cert_time_to_seconds(notafter): return '%s certificate expired %s'% (errstr, notafter) # First read commonName for s in cert.get('subject', []): key, value = s[0] if key == 'commonName': certnames.append(value.lower()) if len(certnames) == 0: return ('%s no commonName found in certificate'% errstr) # Then read subjectAltName for key, value in cert.get('subjectAltName', []): if key == 'DNS': certnames.append(value.lower()) # And finally try to match hostname with one of these names for certname in certnames: if (certname == dnsname or '.' in dnsname and certname == '*.' + dnsname.split('.', 1)[1]): return None return ('%s no matching domain name found in certificate'% errstr) class IdleThread(object): def __init__(self, parent, folder=None): """If invoked without 'folder', perform a NOOP and wait for self.stop() to be called. If invoked with folder, switch to IDLE mode and synchronize once we have a new message""" self.parent = parent self.folder = folder self.stop_sig = Event() self.ui = getglobalui() if folder is None: self.thread = Thread(target=self.noop) else: self.thread = Thread(target=self.__idle) self.thread.setDaemon(1) def start(self): self.thread.start() def stop(self): self.stop_sig.set() def join(self): self.thread.join() def noop(self): # TODO: AFAIK this is not optimal, we will send a NOOP on one # random connection (ie not enough to keep all connections # open). In case we do the noop multiple times, we can well use # the same connection every time, as we get a random one. This # function should IMHO send a noop on ALL available connections # to the server. imapobj = self.parent.acquireconnection() try: imapobj.noop() except imapobj.abort: self.ui.warn('Attempting NOOP on dropped connection %s'% imapobj.identifier) self.parent.releaseconnection(imapobj, True) imapobj = None finally: if imapobj: self.parent.releaseconnection(imapobj) self.stop_sig.wait() # wait until we are supposed to quit def __dosync(self): remoterepos = self.parent.repos account = remoterepos.account localrepos = account.localrepos remoterepos = account.remoterepos statusrepos = account.statusrepos remotefolder = remoterepos.getfolder(self.folder) hook = account.getconf('presynchook', '') account.callhook(hook) offlineimap.accounts.syncfolder(account, remotefolder, quick=False) hook = account.getconf('postsynchook', '') account.callhook(hook) ui = getglobalui() ui.unregisterthread(currentThread()) #syncfolder registered the thread def __idle(self): """Invoke IDLE mode until timeout or self.stop() is invoked.""" def callback(args): """IDLE callback function invoked by imaplib2. This is invoked when a) The IMAP server tells us something while in IDLE mode, b) we get an Exception (e.g. on dropped connections, or c) the standard imaplib IDLE timeout of 29 minutes kicks in.""" result, cb_arg, exc_data = args if exc_data is None and not self.stop_sig.isSet(): # No Exception, and we are not supposed to stop: self.needsync = True self.stop_sig.set() # Continue to sync. while not self.stop_sig.isSet(): self.needsync = False success = False # Successfully selected FOLDER? while not success: imapobj = self.parent.acquireconnection() try: imapobj.select(self.folder) except OfflineImapError as e: if e.severity == OfflineImapError.ERROR.FOLDER_RETRY: # Connection closed, release connection and retry. self.ui.error(e, exc_info()[2]) self.parent.releaseconnection(imapobj, True) elif e.severity == OfflineImapError.ERROR.FOLDER: # Just continue the process on such error for now. self.ui.error(e, exc_info()[2]) else: # Stops future attempts to sync this account. raise else: success = True if "IDLE" in imapobj.capabilities: imapobj.idle(callback=callback) else: self.ui.warn("IMAP IDLE not supported on server '%s'." "Sleep until next refresh cycle."% imapobj.identifier) imapobj.noop() self.stop_sig.wait() # self.stop() or IDLE callback are invoked. try: # End IDLE mode with noop, imapobj can point to a dropped conn. imapobj.noop() except imapobj.abort: self.ui.warn('Attempting NOOP on dropped connection %s'% imapobj.identifier) self.parent.releaseconnection(imapobj, True) else: self.parent.releaseconnection(imapobj) if self.needsync: # Here not via self.stop, but because IDLE responded. Do # another round and invoke actual syncing. self.stop_sig.clear() self.__dosync()