1 #----------------------------------------------------------------------
2 # Copyright (c) 2008 Board of Trustees, Princeton University
4 # Permission is hereby granted, free of charge, to any person obtaining
5 # a copy of this software and/or hardware specification (the "Work") to
6 # deal in the Work without restriction, including without limitation the
7 # rights to use, copy, modify, merge, publish, distribute, sublicense,
8 # and/or sell copies of the Work, and to permit persons to whom the Work
9 # is furnished to do so, subject to the following conditions:
11 # The above copyright notice and this permission notice shall be
12 # included in all copies or substantial portions of the Work.
14 # THE WORK IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
15 # OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
16 # MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
17 # NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
18 # HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
19 # WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
20 # OUT OF OR IN CONNECTION WITH THE WORK OR THE USE OR OTHER DEALINGS
22 #----------------------------------------------------------------------
24 # Implements SFA Credentials
26 # Credentials are signed XML files that assign a subject gid privileges to an object gid
30 from types import StringTypes
32 from StringIO import StringIO
33 from tempfile import mkstemp
34 from xml.dom.minidom import Document, parseString
38 from lxml import etree
43 from xml.parsers.expat import ExpatError
45 from sfa.util.faults import CredentialNotVerifiable, ChildRightsNotSubsetOfParent
46 from sfa.util.sfalogging import logger
47 from sfa.util.sfatime import utcparse, SFATIME_FORMAT
48 from sfa.trust.rights import Right, Rights, determine_rights
49 from sfa.trust.gid import GID
50 from sfa.util.xrn import urn_to_hrn, hrn_authfor_hrn
53 DEFAULT_CREDENTIAL_LIFETIME = 86400 * 28
57 # . make privs match between PG and PL
58 # . Need to add support for other types of credentials, e.g. tickets
59 # . add namespaces to signed-credential element?
61 signature_template = \
63 <Signature xml:id="Sig_%s" xmlns="http://www.w3.org/2000/09/xmldsig#">
65 <CanonicalizationMethod Algorithm="http://www.w3.org/TR/2001/REC-xml-c14n-20010315"/>
66 <SignatureMethod Algorithm="http://www.w3.org/2000/09/xmldsig#rsa-sha1"/>
69 <Transform Algorithm="http://www.w3.org/2000/09/xmldsig#enveloped-signature" />
71 <DigestMethod Algorithm="http://www.w3.org/2000/09/xmldsig#sha1"/>
72 <DigestValue></DigestValue>
87 # PG formats the template (whitespace) slightly differently.
88 # Note that they don't include the xmlns in the template, but add it later.
89 # Otherwise the two are equivalent.
90 #signature_template_as_in_pg = \
92 #<Signature xml:id="Sig_%s" >
94 # <CanonicalizationMethod Algorithm="http://www.w3.org/TR/2001/REC-xml-c14n-20010315"/>
95 # <SignatureMethod Algorithm="http://www.w3.org/2000/09/xmldsig#rsa-sha1"/>
96 # <Reference URI="#%s">
98 # <Transform Algorithm="http://www.w3.org/2000/09/xmldsig#enveloped-signature" />
100 # <DigestMethod Algorithm="http://www.w3.org/2000/09/xmldsig#sha1"/>
101 # <DigestValue></DigestValue>
108 # <X509IssuerSerial/>
117 # Convert a string into a bool
118 # used to convert an xsd:boolean to a Python boolean
120 if str.lower() in ['true','1']:
126 # Utility function to get the text of an XML element
128 def getTextNode(element, subele):
129 sub = element.getElementsByTagName(subele)[0]
130 if len(sub.childNodes) > 0:
131 return sub.childNodes[0].nodeValue
136 # Utility function to set the text of an XML element
137 # It creates the element, adds the text to it,
138 # and then appends it to the parent.
140 def append_sub(doc, parent, element, text):
141 ele = doc.createElement(element)
142 ele.appendChild(doc.createTextNode(text))
143 parent.appendChild(ele)
146 # Signature contains information about an xmlsec1 signature
147 # for a signed-credential
150 class Signature(object):
152 def __init__(self, string=None):
154 self.issuer_gid = None
171 def set_refid(self, id):
174 def get_issuer_gid(self):
179 def set_issuer_gid(self, gid):
184 doc = parseString(self.xml)
186 logger.log_exc ("Failed to parse credential, %s"%self.xml)
188 sig = doc.getElementsByTagName("Signature")[0]
189 self.set_refid(sig.getAttribute("xml:id").strip("Sig_"))
190 keyinfo = sig.getElementsByTagName("X509Data")[0]
191 szgid = getTextNode(keyinfo, "X509Certificate")
192 szgid = "-----BEGIN CERTIFICATE-----\n%s\n-----END CERTIFICATE-----" % szgid
193 self.set_issuer_gid(GID(string=szgid))
196 self.xml = signature_template % (self.get_refid(), self.get_refid())
199 # A credential provides a caller gid with privileges to an object gid.
200 # A signed credential is signed by the object's authority.
202 # Credentials are encoded in one of two ways.
203 # The legacy style (now unsupported) places it in the subjectAltName of an X509 certificate.
204 # The new credentials are placed in signed XML.
207 # In general, a signed credential obtained externally should
208 # not be changed else the signature is no longer valid. So, once
209 # you have loaded an existing signed credential, do not call encode() or sign() on it.
211 def filter_creds_by_caller(creds, caller_hrn_list):
213 Returns a list of creds who's gid caller matches the
216 if not isinstance(creds, list): creds = [creds]
217 if not isinstance(caller_hrn_list, list):
218 caller_hrn_list = [caller_hrn_list]
222 tmp_cred = Credential(string=cred)
223 if tmp_cred.get_gid_caller().get_hrn() in caller_hrn_list:
224 caller_creds.append(cred)
228 class Credential(object):
231 # Create a Credential object
233 # @param create If true, create a blank x509 certificate
234 # @param subject If subject!=None, create an x509 cert with the subject name
235 # @param string If string!=None, load the credential from the string
236 # @param filename If filename!=None, load the credential from the file
237 # FIXME: create and subject are ignored!
238 def __init__(self, create=False, subject=None, string=None, filename=None, cred=None):
239 self.gidCaller = None
240 self.gidObject = None
241 self.expiration = None
242 self.privileges = None
243 self.issuer_privkey = None
244 self.issuer_gid = None
245 self.issuer_pubkey = None
247 self.signature = None
254 if isinstance(cred, StringTypes):
256 self.type = 'geni_sfa'
258 elif isinstance(cred, dict):
259 string = cred['geni_value']
260 self.type = cred['geni_type']
261 self.version = cred['geni_version']
264 if string or filename:
268 str = file(filename).read()
270 # if this is a legacy credential, write error and bail out
271 if isinstance (str, StringTypes) and str.strip().startswith("-----"):
272 logger.error("Legacy credentials not supported any more - giving up with %s..."%str[:10])
278 # Find an xmlsec1 path
279 self.xmlsec_path = ''
280 paths = ['/usr/bin','/usr/local/bin','/bin','/opt/bin','/opt/local/bin']
282 if os.path.isfile(path + '/' + 'xmlsec1'):
283 self.xmlsec_path = path + '/' + 'xmlsec1'
286 def get_subject(self):
288 if not self.gidObject:
291 subject = self.gidObject.get_printable_subject()
294 # sounds like this should be __repr__ instead ??
295 def get_summary_tostring(self):
296 if not self.gidObject:
298 obj = self.gidObject.get_printable_subject()
299 caller = self.gidCaller.get_printable_subject()
300 exp = self.get_expiration()
301 # Summarize the rights too? The issuer?
302 return "[ Grant %s rights on %s until %s ]" % (caller, obj, exp)
304 def get_signature(self):
305 if not self.signature:
307 return self.signature
309 def set_signature(self, sig):
314 # Need the issuer's private key and name
315 # @param key Keypair object containing the private key of the issuer
316 # @param gid GID of the issuing authority
318 def set_issuer_keys(self, privkey, gid):
319 self.issuer_privkey = privkey
320 self.issuer_gid = gid
324 # Set this credential's parent
325 def set_parent(self, cred):
330 # set the GID of the caller
332 # @param gid GID object of the caller
334 def set_gid_caller(self, gid):
336 # gid origin caller is the caller's gid by default
337 self.gidOriginCaller = gid
340 # get the GID of the object
342 def get_gid_caller(self):
343 if not self.gidCaller:
345 return self.gidCaller
348 # set the GID of the object
350 # @param gid GID object of the object
352 def set_gid_object(self, gid):
356 # get the GID of the object
358 def get_gid_object(self):
359 if not self.gidObject:
361 return self.gidObject
364 # Expiration: an absolute UTC time of expiration (as either an int or string or datetime)
366 def set_expiration(self, expiration):
367 expiration_datetime = utcparse (expiration)
368 if expiration_datetime is not None:
369 self.expiration = expiration_datetime
371 logger.error ("unexpected input %s in Credential.set_expiration"%expiration)
374 # get the lifetime of the credential (always in datetime format)
376 def get_expiration(self):
377 if not self.expiration:
379 # at this point self.expiration is normalized as a datetime - DON'T call utcparse again
380 return self.expiration
385 # @param privs either a comma-separated list of privileges of a Rights object
387 def set_privileges(self, privs):
388 if isinstance(privs, str):
389 self.privileges = Rights(string = privs)
391 self.privileges = privs
394 # return the privileges as a Rights object
396 def get_privileges(self):
397 if not self.privileges:
399 return self.privileges
402 # determine whether the credential allows a particular operation to be
405 # @param op_name string specifying name of operation ("lookup", "update", etc)
407 def can_perform(self, op_name):
408 rights = self.get_privileges()
413 return rights.can_perform(op_name)
417 # Encode the attributes of the credential into an XML string
418 # This should be done immediately before signing the credential.
420 # In general, a signed credential obtained externally should
421 # not be changed else the signature is no longer valid. So, once
422 # you have loaded an existing signed credential, do not call encode() or sign() on it.
425 # Create the XML document
427 signed_cred = doc.createElement("signed-credential")
430 # Note that credential/policy.xsd are really the PG schemas
432 # Note that delegation of credentials between the 2 only really works
433 # cause those schemas are identical.
434 # Also note these PG schemas talk about PG tickets and CM policies.
435 signed_cred.setAttribute("xmlns:xsi", "http://www.w3.org/2001/XMLSchema-instance")
436 signed_cred.setAttribute("xsi:noNamespaceSchemaLocation", "http://www.planet-lab.org/resources/sfa/credential.xsd")
437 signed_cred.setAttribute("xsi:schemaLocation", "http://www.planet-lab.org/resources/sfa/ext/policy/1 http://www.planet-lab.org/resources/sfa/ext/policy/1/policy.xsd")
439 # PG says for those last 2:
440 #signed_cred.setAttribute("xsi:noNamespaceSchemaLocation", "http://www.protogeni.net/resources/credential/credential.xsd")
441 # signed_cred.setAttribute("xsi:schemaLocation", "http://www.protogeni.net/resources/credential/ext/policy/1 http://www.protogeni.net/resources/credential/ext/policy/1/policy.xsd")
443 doc.appendChild(signed_cred)
445 # Fill in the <credential> bit
446 cred = doc.createElement("credential")
447 cred.setAttribute("xml:id", self.get_refid())
448 signed_cred.appendChild(cred)
449 append_sub(doc, cred, "type", "privilege")
450 append_sub(doc, cred, "serial", "8")
451 append_sub(doc, cred, "owner_gid", self.gidCaller.save_to_string())
452 append_sub(doc, cred, "owner_urn", self.gidCaller.get_urn())
453 append_sub(doc, cred, "target_gid", self.gidObject.save_to_string())
454 append_sub(doc, cred, "target_urn", self.gidObject.get_urn())
455 append_sub(doc, cred, "uuid", "")
456 if not self.expiration:
457 logger.debug("Creating credential valid for %s s"%DEFAULT_CREDENTIAL_LIFETIME)
458 self.set_expiration(datetime.datetime.utcnow() + datetime.timedelta(seconds=DEFAULT_CREDENTIAL_LIFETIME))
459 self.expiration = self.expiration.replace(microsecond=0)
460 append_sub(doc, cred, "expires", self.expiration.strftime(SFATIME_FORMAT))
461 privileges = doc.createElement("privileges")
462 cred.appendChild(privileges)
465 rights = self.get_privileges()
466 for right in rights.rights:
467 priv = doc.createElement("privilege")
468 append_sub(doc, priv, "name", right.kind)
469 append_sub(doc, priv, "can_delegate", str(right.delegate).lower())
470 privileges.appendChild(priv)
472 # Add the parent credential if it exists
474 sdoc = parseString(self.parent.get_xml())
475 # If the root node is a signed-credential (it should be), then
476 # get all its attributes and attach those to our signed_cred
478 # Specifically, PG and PLadd attributes for namespaces (which is reasonable),
479 # and we need to include those again here or else their signature
480 # no longer matches on the credential.
481 # We expect three of these, but here we copy them all:
482 # signed_cred.setAttribute("xmlns:xsi", "http://www.w3.org/2001/XMLSchema-instance")
483 # and from PG (PL is equivalent, as shown above):
484 # signed_cred.setAttribute("xsi:noNamespaceSchemaLocation", "http://www.protogeni.net/resources/credential/credential.xsd")
485 # signed_cred.setAttribute("xsi:schemaLocation", "http://www.protogeni.net/resources/credential/ext/policy/1 http://www.protogeni.net/resources/credential/ext/policy/1/policy.xsd")
488 # PL now also declares these, with different URLs, so
489 # the code notices those attributes already existed with
490 # different values, and complains.
491 # This happens regularly on delegation now that PG and
492 # PL both declare the namespace with different URLs.
493 # If the content ever differs this is a problem,
494 # but for now it works - different URLs (values in the attributes)
495 # but the same actual schema, so using the PG schema
496 # on delegated-to-PL credentials works fine.
498 # Note: you could also not copy attributes
499 # which already exist. It appears that both PG and PL
500 # will actually validate a slicecred with a parent
501 # signed using PG namespaces and a child signed with PL
502 # namespaces over the whole thing. But I don't know
503 # if that is a bug in xmlsec1, an accident since
504 # the contents of the schemas are the same,
505 # or something else, but it seems odd. And this works.
506 parentRoot = sdoc.documentElement
507 if parentRoot.tagName == "signed-credential" and parentRoot.hasAttributes():
508 for attrIx in range(0, parentRoot.attributes.length):
509 attr = parentRoot.attributes.item(attrIx)
510 # returns the old attribute of same name that was
512 # Below throws InUse exception if we forgot to clone the attribute first
513 oldAttr = signed_cred.setAttributeNode(attr.cloneNode(True))
514 if oldAttr and oldAttr.value != attr.value:
515 msg = "Delegating cred from owner %s to %s over %s:\n - Replaced attribute %s value '%s' with '%s'" % \
516 (self.parent.gidCaller.get_urn(), self.gidCaller.get_urn(), self.gidObject.get_urn(), oldAttr.name, oldAttr.value, attr.value)
518 #raise CredentialNotVerifiable("Can't encode new valid delegated credential: %s" % msg)
520 p_cred = doc.importNode(sdoc.getElementsByTagName("credential")[0], True)
521 p = doc.createElement("parent")
522 p.appendChild(p_cred)
524 # done handling parent credential
526 # Create the <signatures> tag
527 signatures = doc.createElement("signatures")
528 signed_cred.appendChild(signatures)
530 # Add any parent signatures
532 for cur_cred in self.get_credential_list()[1:]:
533 sdoc = parseString(cur_cred.get_signature().get_xml())
534 ele = doc.importNode(sdoc.getElementsByTagName("Signature")[0], True)
535 signatures.appendChild(ele)
537 # Get the finished product
538 self.xml = doc.toxml()
541 def save_to_random_tmp_file(self):
542 fp, filename = mkstemp(suffix='cred', text=True)
543 fp = os.fdopen(fp, "w")
544 self.save_to_file(filename, save_parents=True, filep=fp)
547 def save_to_file(self, filename, save_parents=True, filep=None):
553 f = open(filename, "w")
557 def save_to_string(self, save_parents=True):
567 def set_refid(self, rid):
571 # Figure out what refids exist, and update this credential's id
572 # so that it doesn't clobber the others. Returns the refids of
575 def updateRefID(self):
577 self.set_refid('ref0')
582 next_cred = self.parent
584 refs.append(next_cred.get_refid())
586 next_cred = next_cred.parent
591 # Find a unique refid for this credential
592 rid = self.get_refid()
595 rid = "ref%d" % (val + 1)
600 # Return the set of parent credential ref ids
609 # Sign the XML file created by encode()
612 # In general, a signed credential obtained externally should
613 # not be changed else the signature is no longer valid. So, once
614 # you have loaded an existing signed credential, do not call encode() or sign() on it.
617 if not self.issuer_privkey or not self.issuer_gid:
619 doc = parseString(self.get_xml())
620 sigs = doc.getElementsByTagName("signatures")[0]
622 # Create the signature template to be signed
623 signature = Signature()
624 signature.set_refid(self.get_refid())
625 sdoc = parseString(signature.get_xml())
626 sig_ele = doc.importNode(sdoc.getElementsByTagName("Signature")[0], True)
627 sigs.appendChild(sig_ele)
629 self.xml = doc.toxml()
632 # Split the issuer GID into multiple certificates if it's a chain
633 chain = GID(filename=self.issuer_gid)
636 gid_files.append(chain.save_to_random_tmp_file(False))
637 if chain.get_parent():
638 chain = chain.get_parent()
643 # Call out to xmlsec1 to sign it
644 ref = 'Sig_%s' % self.get_refid()
645 filename = self.save_to_random_tmp_file()
646 signed = os.popen('%s --sign --node-id "%s" --privkey-pem %s,%s %s' \
647 % (self.xmlsec_path, ref, self.issuer_privkey, ",".join(gid_files), filename)).read()
650 for gid_file in gid_files:
660 # Retrieve the attributes of the credential from the XML.
661 # This is automatically called by the various get_* methods of
662 # this class and should not need to be called explicitly.
670 doc = parseString(self.xml)
672 raise CredentialNotVerifiable("Malformed credential")
673 doc = parseString(self.xml)
675 signed_cred = doc.getElementsByTagName("signed-credential")
677 # Is this a signed-cred or just a cred?
678 if len(signed_cred) > 0:
679 creds = signed_cred[0].getElementsByTagName("credential")
680 signatures = signed_cred[0].getElementsByTagName("signatures")
681 if len(signatures) > 0:
682 sigs = signatures[0].getElementsByTagName("Signature")
684 creds = doc.getElementsByTagName("credential")
686 if creds is None or len(creds) == 0:
687 # malformed cred file
688 raise CredentialNotVerifiable("Malformed XML: No credential tag found")
690 # Just take the first cred if there are more than one
693 self.set_refid(cred.getAttribute("xml:id"))
694 self.set_expiration(utcparse(getTextNode(cred, "expires")))
695 self.gidCaller = GID(string=getTextNode(cred, "owner_gid"))
696 self.gidObject = GID(string=getTextNode(cred, "target_gid"))
700 privs = cred.getElementsByTagName("privileges")[0]
702 for priv in privs.getElementsByTagName("privilege"):
703 kind = getTextNode(priv, "name")
704 deleg = str2bool(getTextNode(priv, "can_delegate"))
706 # Convert * into the default privileges for the credential's type
707 # Each inherits the delegatability from the * above
708 _ , type = urn_to_hrn(self.gidObject.get_urn())
709 rl = determine_rights(type, self.gidObject.get_urn())
714 rlist.add(Right(kind.strip(), deleg))
715 self.set_privileges(rlist)
719 parent = cred.getElementsByTagName("parent")
721 parent_doc = parent[0].getElementsByTagName("credential")[0]
722 parent_xml = parent_doc.toxml()
723 self.parent = Credential(string=parent_xml)
726 # Assign the signatures to the credentials
728 Sig = Signature(string=sig.toxml())
730 for cur_cred in self.get_credential_list():
731 if cur_cred.get_refid() == Sig.get_refid():
732 cur_cred.set_signature(Sig)
737 # trusted_certs: A list of trusted GID filenames (not GID objects!)
738 # Chaining is not supported within the GIDs by xmlsec1.
740 # trusted_certs_required: Should usually be true. Set False means an
741 # empty list of trusted_certs would still let this method pass.
742 # It just skips xmlsec1 verification et al. Only used by some utils
745 # . All of the signatures are valid and that the issuers trace back
746 # to trusted roots (performed by xmlsec1)
747 # . The XML matches the credential schema
748 # . That the issuer of the credential is the authority in the target's urn
749 # . In the case of a delegated credential, this must be true of the root
750 # . That all of the gids presented in the credential are valid
751 # . Including verifying GID chains, and includ the issuer
752 # . The credential is not expired
754 # -- For Delegates (credentials with parents)
755 # . The privileges must be a subset of the parent credentials
756 # . The privileges must have "can_delegate" set for each delegated privilege
757 # . The target gid must be the same between child and parents
758 # . The expiry time on the child must be no later than the parent
759 # . The signer of the child must be the owner of the parent
761 # -- Verify does *NOT*
762 # . ensure that an xmlrpc client's gid matches a credential gid, that
763 # must be done elsewhere
765 # @param trusted_certs: The certificates of trusted CA certificates
766 def verify(self, trusted_certs=None, schema=None, trusted_certs_required=True):
770 # validate against RelaxNG schema
772 if schema and os.path.exists(schema):
773 tree = etree.parse(StringIO(self.xml))
774 schema_doc = etree.parse(schema)
775 xmlschema = etree.XMLSchema(schema_doc)
776 if not xmlschema.validate(tree):
777 error = xmlschema.error_log.last_error
778 message = "%s: %s (line %s)" % (self.get_summary_tostring(), error.message, error.line)
779 raise CredentialNotVerifiable(message)
781 if trusted_certs_required and trusted_certs is None:
784 # trusted_cert_objects = [GID(filename=f) for f in trusted_certs]
785 trusted_cert_objects = []
786 ok_trusted_certs = []
787 # If caller explicitly passed in None that means skip cert chain validation.
788 # Strange and not typical
789 if trusted_certs is not None:
790 for f in trusted_certs:
792 # Failures here include unreadable files
794 trusted_cert_objects.append(GID(filename=f))
795 ok_trusted_certs.append(f)
796 except Exception, exc:
797 logger.error("Failed to load trusted cert from %s: %r"%( f, exc))
798 trusted_certs = ok_trusted_certs
800 # make sure it is not expired
801 if self.get_expiration() < datetime.datetime.utcnow():
802 raise CredentialNotVerifiable("Credential %s expired at %s" % \
803 (self.get_summary_tostring(),
804 self.expiration.strftime(SFATIME_FORMAT)))
806 # Verify the signatures
807 filename = self.save_to_random_tmp_file()
808 if trusted_certs is not None:
809 cert_args = " ".join(['--trusted-pem %s' % x for x in trusted_certs])
811 # If caller explicitly passed in None that means skip cert chain validation.
812 # - Strange and not typical
813 if trusted_certs is not None:
814 # Verify the gids of this cred and of its parents
815 for cur_cred in self.get_credential_list():
816 cur_cred.get_gid_object().verify_chain(trusted_cert_objects)
817 cur_cred.get_gid_caller().verify_chain(trusted_cert_objects)
820 refs.append("Sig_%s" % self.get_refid())
822 parentRefs = self.updateRefID()
823 for ref in parentRefs:
824 refs.append("Sig_%s" % ref)
827 # If caller explicitly passed in None that means skip xmlsec1 validation.
828 # Strange and not typical
829 if trusted_certs is None:
832 command = '{} --verify --node-id "{}" {} {} 2>&1'.\
833 format(self.xmlsec_path, ref, cert_args, filename)
834 logger.debug("Running '{}'".format(command))
835 verified = os.popen(command).read()
836 logger.debug("xmlsec command returned {}".format(verified))
837 if not verified.strip().startswith("OK"):
838 # xmlsec errors have a msg= which is the interesting bit.
839 mstart = verified.find("msg=")
841 if mstart > -1 and len(verified) > 4:
843 mend = verified.find('\\', mstart)
844 msg = verified[mstart:mend]
845 raise CredentialNotVerifiable("xmlsec1 error verifying cred %s"
846 "using Signature ID %s: %s %s" % \
847 (self.get_summary_tostring(),
848 ref, msg, verified.strip()))
851 # Verify the parents (delegation)
853 self.verify_parent(self.parent)
855 # Make sure the issuer is the target's authority, and is
857 self.verify_issuer(trusted_cert_objects)
861 # Creates a list of the credential and its parents, with the root
862 # (original delegated credential) as the last item in the list
863 def get_credential_list(self):
867 list.append(cur_cred)
869 cur_cred = cur_cred.parent
875 # Make sure the credential's target gid (a) was signed by or (b)
876 # is the same as the entity that signed the original credential,
877 # or (c) is an authority over the target's namespace.
878 # Also ensure that the credential issuer / signer itself has a valid
879 # GID signature chain (signed by an authority with namespace rights).
880 def verify_issuer(self, trusted_gids):
881 root_cred = self.get_credential_list()[-1]
882 root_target_gid = root_cred.get_gid_object()
883 root_cred_signer = root_cred.get_signature().get_issuer_gid()
886 # Allow non authority to sign target and cred about target.
888 # Why do we need to allow non authorities to sign?
889 # If in the target gid validation step we correctly
890 # checked that the target is only signed by an authority,
891 # then this is just a special case of case 3.
892 # This short-circuit is the common case currently -
893 # and cause GID validation doesn't check 'authority',
894 # this allows users to generate valid slice credentials.
895 if root_target_gid.is_signed_by_cert(root_cred_signer):
896 # cred signer matches target signer, return success
900 # Allow someone to sign credential about themeselves. Used?
901 # If not, remove this.
902 #root_target_gid_str = root_target_gid.save_to_string()
903 #root_cred_signer_str = root_cred_signer.save_to_string()
904 #if root_target_gid_str == root_cred_signer_str:
905 # # cred signer is target, return success
910 # root_cred_signer is not the target_gid
911 # So this is a different gid that we have not verified.
912 # xmlsec1 verified the cert chain on this already, but
913 # it hasn't verified that the gid meets the HRN namespace
915 # Below we'll ensure that it is an authority.
916 # But we haven't verified that it is _signed by_ an authority
917 # We also don't know if xmlsec1 requires that cert signers
920 # Note that if verify() gave us no trusted_gids then this
921 # call will fail. So skip it if we have no trusted_gids
922 if trusted_gids and len(trusted_gids) > 0:
923 root_cred_signer.verify_chain(trusted_gids)
925 logger.debug("No trusted gids. Cannot verify that cred signer is signed by a trusted authority. Skipping that check.")
927 # See if the signer is an authority over the domain of the target.
928 # There are multiple types of authority - accept them all here
929 # Maybe should be (hrn, type) = urn_to_hrn(root_cred_signer.get_urn())
930 root_cred_signer_type = root_cred_signer.get_type()
931 if (root_cred_signer_type.find('authority') == 0):
932 #logger.debug('Cred signer is an authority')
933 # signer is an authority, see if target is in authority's domain
934 signerhrn = root_cred_signer.get_hrn()
935 if hrn_authfor_hrn(signerhrn, root_target_gid.get_hrn()):
938 # We've required that the credential be signed by an authority
939 # for that domain. Reasonable and probably correct.
940 # A looser model would also allow the signer to be an authority
941 # in my control framework - eg My CA or CH. Even if it is not
942 # the CH that issued these, eg, user credentials.
944 # Give up, credential does not pass issuer verification
946 raise CredentialNotVerifiable("Could not verify credential owned by %s for object %s. Cred signer %s not the trusted authority for Cred target %s" % \
947 (self.gidCaller.get_urn(), self.gidObject.get_urn(), root_cred_signer.get_hrn(), root_target_gid.get_hrn()))
951 # -- For Delegates (credentials with parents) verify that:
952 # . The privileges must be a subset of the parent credentials
953 # . The privileges must have "can_delegate" set for each delegated privilege
954 # . The target gid must be the same between child and parents
955 # . The expiry time on the child must be no later than the parent
956 # . The signer of the child must be the owner of the parent
957 def verify_parent(self, parent_cred):
958 # make sure the rights given to the child are a subset of the
959 # parents rights (and check delegate bits)
960 if not parent_cred.get_privileges().is_superset(self.get_privileges()):
961 raise ChildRightsNotSubsetOfParent(("Parent cred ref %s rights " % parent_cred.get_refid()) +
962 self.parent.get_privileges().save_to_string() + (" not superset of delegated cred %s ref %s rights " % \
963 (self.get_summary_tostring(), self.get_refid())) +
964 self.get_privileges().save_to_string())
966 # make sure my target gid is the same as the parent's
967 if not parent_cred.get_gid_object().save_to_string() == \
968 self.get_gid_object().save_to_string():
969 raise CredentialNotVerifiable("Delegated cred %s: Target gid not equal between parent and child. Parent %s" % \
970 (self.get_summary_tostring(), parent_cred.get_summary_tostring()))
972 # make sure my expiry time is <= my parent's
973 if not parent_cred.get_expiration() >= self.get_expiration():
974 raise CredentialNotVerifiable("Delegated credential %s expires after parent %s" % \
975 (self.get_summary_tostring(), parent_cred.get_summary_tostring()))
977 # make sure my signer is the parent's caller
978 if not parent_cred.get_gid_caller().save_to_string(False) == \
979 self.get_signature().get_issuer_gid().save_to_string(False):
980 raise CredentialNotVerifiable("Delegated credential %s not signed by parent %s's caller" % \
981 (self.get_summary_tostring(), parent_cred.get_summary_tostring()))
984 if parent_cred.parent:
985 parent_cred.verify_parent(parent_cred.parent)
988 def delegate(self, delegee_gidfile, caller_keyfile, caller_gidfile):
990 Return a delegated copy of this credential, delegated to the
991 specified gid's user.
993 # get the gid of the object we are delegating
994 object_gid = self.get_gid_object()
995 object_hrn = object_gid.get_hrn()
997 # the hrn of the user who will be delegated to
998 delegee_gid = GID(filename=delegee_gidfile)
999 delegee_hrn = delegee_gid.get_hrn()
1001 #user_key = Keypair(filename=keyfile)
1002 #user_hrn = self.get_gid_caller().get_hrn()
1003 subject_string = "%s delegated to %s" % (object_hrn, delegee_hrn)
1004 dcred = Credential(subject=subject_string)
1005 dcred.set_gid_caller(delegee_gid)
1006 dcred.set_gid_object(object_gid)
1007 dcred.set_parent(self)
1008 dcred.set_expiration(self.get_expiration())
1009 dcred.set_privileges(self.get_privileges())
1010 dcred.get_privileges().delegate_all_privileges(True)
1011 #dcred.set_issuer_keys(keyfile, delegee_gidfile)
1012 dcred.set_issuer_keys(caller_keyfile, caller_gidfile)
1019 def get_filename(self):
1020 return getattr(self,'filename',None)
1022 def actual_caller_hrn (self):
1023 """a helper method used by some API calls like e.g. Allocate
1024 to try and find out who really is the original caller
1026 This admittedly is a bit of a hack, please USE IN LAST RESORT
1028 This code uses a heuristic to identify a delegated credential
1030 A first known restriction if for traffic that gets through a slice manager
1031 in this case the hrn reported is the one from the last SM in the call graph
1032 which is not at all what is meant here"""
1034 caller_hrn = self.get_gid_caller().get_hrn()
1035 issuer_hrn = self.get_signature().get_issuer_gid().get_hrn()
1036 subject_hrn = self.get_gid_object().get_hrn()
1037 # if we find that the caller_hrn is an immediate descendant of the issuer, then
1038 # this seems to be a 'regular' credential
1039 if caller_hrn.startswith(issuer_hrn):
1040 actual_caller_hrn=caller_hrn
1041 # else this looks like a delegated credential, and the real caller is the issuer
1043 actual_caller_hrn=issuer_hrn
1044 logger.info("actual_caller_hrn: caller_hrn=%s, issuer_hrn=%s, returning %s"%(caller_hrn,issuer_hrn,actual_caller_hrn))
1045 return actual_caller_hrn
1048 # Dump the contents of a credential to stdout in human-readable format
1050 # @param dump_parents If true, also dump the parent certificates
1051 def dump (self, *args, **kwargs):
1052 print self.dump_string(*args, **kwargs)
1054 # show_xml is ignored
1055 def dump_string(self, dump_parents=False, show_xml=None):
1057 result += "CREDENTIAL %s\n" % self.get_subject()
1058 filename=self.get_filename()
1059 if filename: result += "Filename %s\n"%filename
1060 privileges = self.get_privileges()
1062 result += " privs: %s\n" % privileges.save_to_string()
1064 result += " privs: \n"
1065 gidCaller = self.get_gid_caller()
1067 result += " gidCaller:\n"
1068 result += gidCaller.dump_string(8, dump_parents)
1070 if self.get_signature():
1072 self.get_signature().get_issuer_gid().dump(8, dump_parents)
1075 print " expiration:", self.expiration.strftime(SFATIME_FORMAT)
1077 gidObject = self.get_gid_object()
1079 result += " gidObject:\n"
1080 result += gidObject.dump_string(8, dump_parents)
1082 if self.parent and dump_parents:
1083 result += "\nPARENT"
1084 result += self.parent.dump_string(True)