X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=sfa%2Fclient%2Fsfaclientlib.py;h=521a220b55cb4cae1ea9b0312dc2451151456381;hb=999893377056972a8ac599135dee3f6cbe530f3f;hp=ba8f502da36dd9adc3cea793b8c9b1d559f8187f;hpb=205bc659a512d77edd19358f724209983225bc43;p=sfa.git diff --git a/sfa/client/sfaclientlib.py b/sfa/client/sfaclientlib.py index ba8f502d..521a220b 100644 --- a/sfa/client/sfaclientlib.py +++ b/sfa/client/sfaclientlib.py @@ -3,40 +3,24 @@ # a minimal library for writing "lightweight" SFA clients # +# xxx todo +# this library should probably check for the expiration date of the various +# certificates and automatically retrieve fresh ones when expired + +import sys import os,os.path +from datetime import datetime import sfa.util.sfalogging +# importing sfa.utils.faults does pull a lot of stuff +# OTOH it's imported from Certificate anyways, so.. +from sfa.util.faults import RecordNotFound -# what we use on GID actually is inherited from Certificate -#from sfa.trust.gid import GID -from sfa.trust.certificate import Keypair, Certificate -# what we need in the Credential class essentially amounts to saving the incoming result -# in a file as the output from the registry already is under xml format -#from sfa.trust.credential import Credential - -import sfa.client.sfaprotocol as sfaprotocol - -class SfaServerProxy: - - def __init__ (self, url, keyfile, certfile, verbose=False, timeout=None): - self.url=url - self.keyfile=keyfile - self.certfile=certfile - self.verbose=verbose - self.timeout=timeout - # an instance of xmlrpclib.ServerProxy - self.serverproxy=sfaprotocol.server_proxy \ - (self.url, self.keyfile, self.certfile, self.timeout, self.verbose) - - # this is python magic to return the code to run when - # SfaServerProxy receives a method call - # so essentially we send the same method with identical arguments - # to the server_proxy object - def __getattr__(self, name): - def func(*args, **kwds): - return getattr(self.serverproxy, name)(*args, **kwds) - return func +from sfa.client.sfaserverproxy import SfaServerProxy +# see optimizing dependencies below +from sfa.trust.certificate import Keypair, Certificate +from sfa.trust.credential import Credential ########## # a helper class to implement the bootstrapping of crypto. material # assuming we are starting from scratch on the client side @@ -54,30 +38,191 @@ class SfaServerProxy: # obtained at the registry using Resolve # using the step2 credential as credential # default filename is .user.gid -########## -# from that point on, the GID can/should be used as the SSL cert for anything -# a new (slice) credential would be needed for slice operations and can be -# obtained at the registry through GetCredential +# +# From that point on, the GID is used as the SSL certificate +# and the following can be done +# +# (**) retrieve a slice (or authority) credential +# obtained at the registry with GetCredential +# using the (step2) user-credential as credential +# default filename is ..cred +# (**) retrieve a slice (or authority) GID +# obtained at the registry with Resolve +# using the (step2) user-credential as credential +# default filename is ..cred + + +########## Implementation notes +# +# (*) decorators +# +# this implementation is designed as a guideline for +# porting to other languages +# +# the decision to go for decorators aims at focusing +# on the core of what needs to be done when everything +# works fine, and to take caching and error management +# out of the way +# +# for non-pythonic developers, it should be enough to +# implement the bulk of this code, namely the _produce methods +# and to add caching and error management by whichever means +# is available, including inline +# +# (*) self-signed certificates +# +# still with other languages in mind, we've tried to keep the +# dependencies to the rest of the code as low as possible +# +# however this still relies on the sfa.trust.certificate module +# for the initial generation of a self-signed-certificate that +# is associated to the user's ssh-key +# (for user-friendliness, and for smooth operations with planetlab, +# the usage model is to reuse an existing keypair) +# +# there might be a more portable, i.e. less language-dependant way, to +# implement this step by exec'ing the openssl command a known +# successful attempt at this approach that worked for Java is +# documented below +# http://nam.ece.upatras.gr/fstoolkit/trac/wiki/JavaSFAClient +# +#################### + +class SfaClientException (Exception): pass -# xxx todo should protect against write file permissions -# xxx todo review exceptions class SfaClientBootstrap: - # xxx todo should account for verbose and timeout that the proxy offers - def __init__ (self, user_hrn, registry_url, dir=None, logger=None): + # dir is mandatory but defaults to '.' + def __init__ (self, user_hrn, registry_url, dir=None, + verbose=False, timeout=None, logger=None): self.hrn=user_hrn self.registry_url=registry_url if dir is None: dir="." self.dir=dir + self.verbose=verbose + self.timeout=timeout + # default for the logger is to use the global sfa logger if logger is None: - print 'special case for logger' logger = sfa.util.sfalogging.logger self.logger=logger + ######################################## *_produce methods + ### step1 + # unconditionnally create a self-signed certificate + def self_signed_cert_produce (self,output): + self.assert_private_key() + private_key_filename = self.private_key_filename() + keypair=Keypair(filename=private_key_filename) + self_signed = Certificate (subject = self.hrn) + self_signed.set_pubkey (keypair) + self_signed.set_issuer (keypair, self.hrn) + self_signed.sign () + self_signed.save_to_file (output) + self.logger.debug("SfaClientBootstrap: Created self-signed certificate for %s in %s"%\ + (self.hrn,output)) + return output + + ### step2 + # unconditionnally retrieve my credential (GetSelfCredential) + # we always use the self-signed-cert as the SSL cert + def my_credential_produce (self, output): + self.assert_self_signed_cert() + certificate_filename = self.self_signed_cert_filename() + certificate_string = self.plain_read (certificate_filename) + self.assert_private_key() + registry_proxy = SfaServerProxy (self.registry_url, self.private_key_filename(), + certificate_filename) + credential_string=registry_proxy.GetSelfCredential (certificate_string, self.hrn, "user") + self.plain_write (output, credential_string) + self.logger.debug("SfaClientBootstrap: Wrote result of GetSelfCredential in %s"%output) + return output + + ### step3 + # unconditionnally retrieve my GID - use the general form + def my_gid_produce (self,output): + return self.gid_produce (output, self.hrn, "user") + + ### retrieve any credential (GetCredential) unconditionnal form + # we always use the GID as the SSL cert + def credential_produce (self, output, hrn, type): + self.assert_my_gid() + certificate_filename = self.my_gid_filename() + self.assert_private_key() + registry_proxy = SfaServerProxy (self.registry_url, self.private_key_filename(), + certificate_filename) + self.assert_my_credential() + my_credential_string = self.my_credential_string() + credential_string=registry_proxy.GetCredential (my_credential_string, hrn, type) + self.plain_write (output, credential_string) + self.logger.debug("SfaClientBootstrap: Wrote result of GetCredential in %s"%output) + return output + + def slice_credential_produce (self, output, hrn): + return self.credential_produce (output, hrn, "slice") + + def authority_credential_produce (self, output, hrn): + return self.credential_produce (output, hrn, "authority") + + ### retrieve any gid (Resolve) - unconditionnal form + # use my GID when available as the SSL cert, otherwise the self-signed + def gid_produce (self, output, hrn, type ): + try: + self.assert_my_gid() + certificate_filename = self.my_gid_filename() + except: + self.assert_self_signed_cert() + certificate_filename = self.self_signed_cert_filename() + + self.assert_private_key() + registry_proxy = SfaServerProxy (self.registry_url, self.private_key_filename(), + certificate_filename) + credential_string=self.plain_read (self.my_credential()) + records = registry_proxy.Resolve (hrn, credential_string) + records=[record for record in records if record['type']==type] + if not records: + raise RecordNotFound, "hrn %s (%s) unknown to registry %s"%(hrn,type,self.registry_url) + record=records[0] + self.plain_write (output, record['gid']) + self.logger.debug("SfaClientBootstrap: Wrote GID for %s (%s) in %s"% (hrn,type,output)) + return output + + + # Returns True if credential file is valid. Otherwise return false. + def validate_credential(self, filename): + valid = True + cred = Credential(filename=filename) + # check if credential is expires + if cred.get_expiration() < datetime.now(): + valid = False + return valid + + #################### public interface + + # return my_gid, run all missing steps in the bootstrap sequence + def bootstrap_my_gid (self): + self.self_signed_cert() + self.my_credential() + return self.my_gid() + + # once we've bootstrapped we can use this object to issue any other SFA call + # always use my gid + def server_proxy (self, url): + self.assert_my_gid() + return SfaServerProxy (url, self.private_key_filename(), self.my_gid_filename(), + verbose=self.verbose, timeout=self.timeout) - # xxx should that be called in the constructor ? - # typically user_private_key is ~/.ssh/id_rsa + # now in some cases the self-signed is enough + def server_proxy_simple (self, url): + self.assert_self_signed_cert() + return SfaServerProxy (url, self.private_key_filename(), self.self_signed_cert_filename(), + verbose=self.verbose, timeout=self.timeout) + + # this method can optionnally be invoked to ensure proper + # installation of the private key that belongs to this user + # installs private_key in working dir with expected name -- preserve mode + # typically user_private_key would be ~/.ssh/id_rsa + # xxx should probably check the 2 files are identical def init_private_key_if_missing (self, user_private_key): private_key_filename=self.private_key_filename() if not os.path.isfile (private_key_filename): @@ -87,40 +232,33 @@ class SfaClientBootstrap: self.logger.debug("SfaClientBootstrap: Copied private key from %s into %s"%\ (user_private_key,private_key_filename)) - # make sure we have the GID at hand - def bootstrap_gid (self): - if self.any_certificate_filename() is None: - self.get_self_signed_cert() - self.get_credential() - self.get_gid() - - def server_proxy (self, url): - return SfaServerProxy (url, self.private_key_filename(), self.gid_filename()) - - def get_credential_string (self): - return self.plain_read (self.get_credential()) - - # more to come to get credentials about other objects (authority/slice) - #################### private details # stupid stuff def fullpath (self, file): return os.path.join (self.dir,file) - # %s -> self.hrn - def fullpath_format(self,format): return self.fullpath (format%self.hrn) + # the expected filenames for the various pieces def private_key_filename (self): - return self.fullpath_format ("%s.pkey") + return self.fullpath ("%s.pkey"%self.hrn) def self_signed_cert_filename (self): - return self.fullpath_format ("%s.sscert") - def credential_filename (self): - return self.fullpath_format ("%s.user.cred") - def gid_filename (self): - return self.fullpath_format ("%s.user.gid") + return self.fullpath ("%s.sscert"%self.hrn) + def my_credential_filename (self): + return self.credential_filename (self.hrn, "user") + def credential_filename (self, hrn, type): + return self.fullpath ("%s.%s.cred"%(hrn,type)) + def slice_credential_filename (self, hrn): + return self.credential_filename(hrn,'slice') + def authority_credential_filename (self, hrn): + return self.credential_filename(hrn,'authority') + def my_gid_filename (self): + return self.gid_filename (self.hrn, "user") + def gid_filename (self, hrn, type): + return self.fullpath ("%s.%s.gid"%(hrn,type)) + # optimizing dependencies # originally we used classes GID or Credential or Certificate # like e.g. -# return Credential(filename=self.get_credential()).save_to_string() +# return Credential(filename=self.my_credential()).save_to_string() # but in order to make it simpler to other implementations/languages.. def plain_read (self, filename): infile=file(filename,"r") @@ -133,82 +271,80 @@ class SfaClientBootstrap: result=outfile.write(contents) outfile.close() - # the private key - def check_private_key (self): - if not os.path.isfile (self.private_key_filename()): - raise Exception,"No such file %s"%self.private_key_filename() + def assert_filename (self, filename, kind): + if not os.path.isfile (filename): + raise IOError,"Missing %s file %s"%(kind,filename) return True + + def assert_private_key (self): return self.assert_filename (self.private_key_filename(),"private key") + def assert_self_signed_cert (self): return self.assert_filename (self.self_signed_cert_filename(),"self-signed certificate") + def assert_my_credential (self): return self.assert_filename (self.my_credential_filename(),"user's credential") + def assert_my_gid (self): return self.assert_filename (self.my_gid_filename(),"user's GID") - # get any certificate - # rationale for this method, once we have the gid, it's actually safe - # to remove the .sscert - def any_certificate_filename (self): - attempts=[ self.gid_filename(), self.self_signed_cert_filename() ] - for attempt in attempts: - if os.path.isfile (attempt): return attempt - return None - ### step1 - # unconditionnally - def create_self_signed_certificate (self,output): - self.check_private_key() - private_key_filename = self.private_key_filename() - keypair=Keypair(filename=private_key_filename) - self_signed = Certificate (subject = self.hrn) - self_signed.set_pubkey (keypair) - self_signed.set_issuer (keypair, self.hrn) - self_signed.sign () - self_signed.save_to_file (output) - self.logger.debug("SfaClientBootstrap: Created self-signed certificate for %s in %s"%\ - (self.hrn,output)) - return output + # decorator to make up the other methods + def get_or_produce (filename_method, produce_method, validate_method=None): + # default validator returns true + def wrap (f): + def wrapped (self, *args, **kw): + filename=filename_method (self, *args, **kw) + if os.path.isfile ( filename ): + if not validate_method: + return filename + elif validate_method(self, filename): + return filename + else: + # remove invalid file + self.logger.warning ("Removing %s - has expired"%filename) + os.unlink(filename) + try: + produce_method (self, filename, *args, **kw) + return filename + except IOError: + raise + except : + error = sys.exc_info()[:2] + message="Could not produce/retrieve %s (%s -- %s)"%\ + (filename,error[0],error[1]) + self.logger.log_exc(message) + raise Exception, message + return wrapped + return wrap - def get_self_signed_cert (self): - self_signed_cert_filename = self.self_signed_cert_filename() - if os.path.isfile (self_signed_cert_filename): - return self_signed_cert_filename - return self.create_self_signed_certificate(self_signed_cert_filename) - - ### step2 - # unconditionnally - def retrieve_credential (self, output): - self.check_private_key() - certificate_filename = self.any_certificate_filename() - certificate_string = self.plain_read (certificate_filename) - registry_proxy = SfaServerProxy (self.registry_url, self.private_key_filename(), - certificate_filename) - credential_string=registry_proxy.GetSelfCredential (certificate_string, self.hrn, "user") - self.plain_write (output, credential_string) - self.logger.debug("SfaClientBootstrap: Wrote result of GetSelfCredential in %s"%output) - return output + @get_or_produce (self_signed_cert_filename, self_signed_cert_produce) + def self_signed_cert (self): pass - def get_credential (self): - credential_filename = self.credential_filename () - if os.path.isfile(credential_filename): - return credential_filename - return self.retrieve_credential (credential_filename) + @get_or_produce (my_credential_filename, my_credential_produce, validate_credential) + def my_credential (self): pass - ### step3 - # unconditionnally - def retrieve_gid (self, hrn, type, output): - self.check_private_key() - certificate_filename = self.any_certificate_filename() - registry_proxy = SfaServerProxy (self.registry_url, self.private_key_filename(), - certificate_filename) - credential_string=self.plain_read (self.get_credential()) - records = registry_proxy.Resolve (hrn, credential_string) - records=[record for record in records if record['type']==type] - if not records: - # RecordNotFound - raise Exception, "hrn %s (%s) unknown to registry %s"%(hrn,type,self.registry_url) - record=records[0] - self.plain_write (output, record['gid']) - self.logger.debug("SfaClientBootstrap: Wrote GID for %s (%s) in %s"% (hrn,type,output)) - return output - - def get_gid (self): - gid_filename=self.gid_filename() - if os.path.isfile(gid_filename): - return gid_filename - return self.retrieve_gid(self.hrn, "user", gid_filename) + @get_or_produce (my_gid_filename, my_gid_produce) + def my_gid (self): pass + + @get_or_produce (credential_filename, credential_produce, validate_credential) + def credential (self, hrn, type): pass + + @get_or_produce (slice_credential_filename, slice_credential_produce, validate_credential) + def slice_credential (self, hrn): pass + + @get_or_produce (authority_credential_filename, authority_credential_produce, validate_credential) + def authority_credential (self, hrn): pass + + @get_or_produce (gid_filename, gid_produce) + def gid (self, hrn, type ): pass + + + # get the credentials as strings, for inserting as API arguments + def my_credential_string (self): + self.my_credential() + return self.plain_read(self.my_credential_filename()) + def slice_credential_string (self, hrn): + self.slice_credential(hrn) + return self.plain_read(self.slice_credential_filename(hrn)) + def authority_credential_string (self, hrn): + self.authority_credential(hrn) + return self.plain_read(self.authority_credential_filename(hrn)) + # for consistency + def private_key (self): + self.assert_private_key() + return self.private_key_filename()