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 = 2 * 3600
54 #DEFAULT_CREDENTIAL_LIFETIME = 86400 * 31
58 # . make privs match between PG and PL
59 # . Need to add support for other types of credentials, e.g. tickets
60 # . add namespaces to signed-credential element?
62 signature_template = \
64 <Signature xml:id="Sig_%s" xmlns="http://www.w3.org/2000/09/xmldsig#">
66 <CanonicalizationMethod Algorithm="http://www.w3.org/TR/2001/REC-xml-c14n-20010315"/>
67 <SignatureMethod Algorithm="http://www.w3.org/2000/09/xmldsig#rsa-sha1"/>
70 <Transform Algorithm="http://www.w3.org/2000/09/xmldsig#enveloped-signature" />
72 <DigestMethod Algorithm="http://www.w3.org/2000/09/xmldsig#sha1"/>
73 <DigestValue></DigestValue>
88 # PG formats the template (whitespace) slightly differently.
89 # Note that they don't include the xmlns in the template, but add it later.
90 # Otherwise the two are equivalent.
91 #signature_template_as_in_pg = \
93 #<Signature xml:id="Sig_%s" >
95 # <CanonicalizationMethod Algorithm="http://www.w3.org/TR/2001/REC-xml-c14n-20010315"/>
96 # <SignatureMethod Algorithm="http://www.w3.org/2000/09/xmldsig#rsa-sha1"/>
97 # <Reference URI="#%s">
99 # <Transform Algorithm="http://www.w3.org/2000/09/xmldsig#enveloped-signature" />
101 # <DigestMethod Algorithm="http://www.w3.org/2000/09/xmldsig#sha1"/>
102 # <DigestValue></DigestValue>
109 # <X509IssuerSerial/>
118 # Convert a string into a bool
119 # used to convert an xsd:boolean to a Python boolean
121 if str.lower() in ['true','1']:
127 # Utility function to get the text of an XML element
129 def getTextNode(element, subele):
130 sub = element.getElementsByTagName(subele)[0]
131 if len(sub.childNodes) > 0:
132 return sub.childNodes[0].nodeValue
137 # Utility function to set the text of an XML element
138 # It creates the element, adds the text to it,
139 # and then appends it to the parent.
141 def append_sub(doc, parent, element, text):
142 ele = doc.createElement(element)
143 ele.appendChild(doc.createTextNode(text))
144 parent.appendChild(ele)
147 # Signature contains information about an xmlsec1 signature
148 # for a signed-credential
151 class Signature(object):
153 def __init__(self, string=None):
155 self.issuer_gid = None
172 def set_refid(self, id):
175 def get_issuer_gid(self):
180 def set_issuer_gid(self, gid):
185 doc = parseString(self.xml)
187 logger.log_exc ("Failed to parse credential, %s"%self.xml)
189 sig = doc.getElementsByTagName("Signature")[0]
190 self.set_refid(sig.getAttribute("xml:id").strip("Sig_"))
191 keyinfo = sig.getElementsByTagName("X509Data")[0]
192 szgid = getTextNode(keyinfo, "X509Certificate")
193 szgid = "-----BEGIN CERTIFICATE-----\n%s\n-----END CERTIFICATE-----" % szgid
194 self.set_issuer_gid(GID(string=szgid))
197 self.xml = signature_template % (self.get_refid(), self.get_refid())
200 # A credential provides a caller gid with privileges to an object gid.
201 # A signed credential is signed by the object's authority.
203 # Credentials are encoded in one of two ways.
204 # The legacy style (now unsupported) places it in the subjectAltName of an X509 certificate.
205 # The new credentials are placed in signed XML.
208 # In general, a signed credential obtained externally should
209 # not be changed else the signature is no longer valid. So, once
210 # you have loaded an existing signed credential, do not call encode() or sign() on it.
212 def filter_creds_by_caller(creds, caller_hrn_list):
214 Returns a list of creds who's gid caller matches the
217 if not isinstance(creds, list): creds = [creds]
218 if not isinstance(caller_hrn_list, list):
219 caller_hrn_list = [caller_hrn_list]
223 tmp_cred = Credential(string=cred)
224 if tmp_cred.get_gid_caller().get_hrn() in caller_hrn_list:
225 caller_creds.append(cred)
229 class Credential(object):
232 # Create a Credential object
234 # @param create If true, create a blank x509 certificate
235 # @param subject If subject!=None, create an x509 cert with the subject name
236 # @param string If string!=None, load the credential from the string
237 # @param filename If filename!=None, load the credential from the file
238 # FIXME: create and subject are ignored!
239 def __init__(self, create=False, subject=None, string=None, filename=None, cred=None):
240 self.gidCaller = None
241 self.gidObject = None
242 self.expiration = None
243 self.privileges = None
244 self.issuer_privkey = None
245 self.issuer_gid = None
246 self.issuer_pubkey = None
248 self.signature = None
255 if isinstance(cred, StringTypes):
257 self.type = 'geni_sfa'
259 elif isinstance(cred, dict):
260 string = cred['geni_value']
261 self.type = cred['geni_type']
262 self.version = cred['geni_version']
265 if string or filename:
269 str = file(filename).read()
271 # if this is a legacy credential, write error and bail out
272 if isinstance (str, StringTypes) and str.strip().startswith("-----"):
273 logger.error("Legacy credentials not supported any more - giving up with %s..."%str[:10])
279 # Find an xmlsec1 path
280 self.xmlsec_path = ''
281 paths = ['/usr/bin','/usr/local/bin','/bin','/opt/bin','/opt/local/bin']
283 if os.path.isfile(path + '/' + 'xmlsec1'):
284 self.xmlsec_path = path + '/' + 'xmlsec1'
287 def get_subject(self):
289 if not self.gidObject:
292 subject = self.gidObject.get_printable_subject()
295 # sounds like this should be __repr__ instead ??
296 def get_summary_tostring(self):
297 if not self.gidObject:
299 obj = self.gidObject.get_printable_subject()
300 caller = self.gidCaller.get_printable_subject()
301 exp = self.get_expiration()
302 # Summarize the rights too? The issuer?
303 return "[ Grant %s rights on %s until %s ]" % (caller, obj, exp)
305 def get_signature(self):
306 if not self.signature:
308 return self.signature
310 def set_signature(self, sig):
315 # Need the issuer's private key and name
316 # @param key Keypair object containing the private key of the issuer
317 # @param gid GID of the issuing authority
319 def set_issuer_keys(self, privkey, gid):
320 self.issuer_privkey = privkey
321 self.issuer_gid = gid
325 # Set this credential's parent
326 def set_parent(self, cred):
331 # set the GID of the caller
333 # @param gid GID object of the caller
335 def set_gid_caller(self, gid):
337 # gid origin caller is the caller's gid by default
338 self.gidOriginCaller = gid
341 # get the GID of the object
343 def get_gid_caller(self):
344 if not self.gidCaller:
346 return self.gidCaller
349 # set the GID of the object
351 # @param gid GID object of the object
353 def set_gid_object(self, gid):
357 # get the GID of the object
359 def get_gid_object(self):
360 if not self.gidObject:
362 return self.gidObject
365 # Expiration: an absolute UTC time of expiration (as either an int or string or datetime)
367 def set_expiration(self, expiration):
368 expiration_datetime = utcparse (expiration)
369 if expiration_datetime is not None:
370 self.expiration = expiration_datetime
372 logger.error ("unexpected input %s in Credential.set_expiration"%expiration)
375 # get the lifetime of the credential (always in datetime format)
377 def get_expiration(self):
378 if not self.expiration:
380 # at this point self.expiration is normalized as a datetime - DON'T call utcparse again
381 return self.expiration
386 # @param privs either a comma-separated list of privileges of a Rights object
388 def set_privileges(self, privs):
389 if isinstance(privs, str):
390 self.privileges = Rights(string = privs)
392 self.privileges = privs
395 # return the privileges as a Rights object
397 def get_privileges(self):
398 if not self.privileges:
400 return self.privileges
403 # determine whether the credential allows a particular operation to be
406 # @param op_name string specifying name of operation ("lookup", "update", etc)
408 def can_perform(self, op_name):
409 rights = self.get_privileges()
414 return rights.can_perform(op_name)
418 # Encode the attributes of the credential into an XML string
419 # This should be done immediately before signing the credential.
421 # In general, a signed credential obtained externally should
422 # not be changed else the signature is no longer valid. So, once
423 # you have loaded an existing signed credential, do not call encode() or sign() on it.
426 # Create the XML document
428 signed_cred = doc.createElement("signed-credential")
431 # Note that credential/policy.xsd are really the PG schemas
433 # Note that delegation of credentials between the 2 only really works
434 # cause those schemas are identical.
435 # Also note these PG schemas talk about PG tickets and CM policies.
436 signed_cred.setAttribute("xmlns:xsi", "http://www.w3.org/2001/XMLSchema-instance")
437 signed_cred.setAttribute("xsi:noNamespaceSchemaLocation", "http://www.planet-lab.org/resources/sfa/credential.xsd")
438 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")
440 # PG says for those last 2:
441 #signed_cred.setAttribute("xsi:noNamespaceSchemaLocation", "http://www.protogeni.net/resources/credential/credential.xsd")
442 # 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")
444 doc.appendChild(signed_cred)
446 # Fill in the <credential> bit
447 cred = doc.createElement("credential")
448 cred.setAttribute("xml:id", self.get_refid())
449 signed_cred.appendChild(cred)
450 append_sub(doc, cred, "type", "privilege")
451 append_sub(doc, cred, "serial", "8")
452 append_sub(doc, cred, "owner_gid", self.gidCaller.save_to_string())
453 append_sub(doc, cred, "owner_urn", self.gidCaller.get_urn())
454 append_sub(doc, cred, "target_gid", self.gidObject.save_to_string())
455 append_sub(doc, cred, "target_urn", self.gidObject.get_urn())
456 append_sub(doc, cred, "uuid", "")
457 if not self.expiration:
458 logger.debug("Creating credential valid for %s s"%DEFAULT_CREDENTIAL_LIFETIME)
459 self.set_expiration(datetime.datetime.utcnow() + datetime.timedelta(seconds=DEFAULT_CREDENTIAL_LIFETIME))
460 self.expiration = self.expiration.replace(microsecond=0)
461 append_sub(doc, cred, "expires", self.expiration.strftime(SFATIME_FORMAT))
462 privileges = doc.createElement("privileges")
463 cred.appendChild(privileges)
466 rights = self.get_privileges()
467 for right in rights.rights:
468 priv = doc.createElement("privilege")
469 append_sub(doc, priv, "name", right.kind)
470 append_sub(doc, priv, "can_delegate", str(right.delegate).lower())
471 privileges.appendChild(priv)
473 # Add the parent credential if it exists
475 sdoc = parseString(self.parent.get_xml())
476 # If the root node is a signed-credential (it should be), then
477 # get all its attributes and attach those to our signed_cred
479 # Specifically, PG and PLadd attributes for namespaces (which is reasonable),
480 # and we need to include those again here or else their signature
481 # no longer matches on the credential.
482 # We expect three of these, but here we copy them all:
483 # signed_cred.setAttribute("xmlns:xsi", "http://www.w3.org/2001/XMLSchema-instance")
484 # and from PG (PL is equivalent, as shown above):
485 # signed_cred.setAttribute("xsi:noNamespaceSchemaLocation", "http://www.protogeni.net/resources/credential/credential.xsd")
486 # 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")
489 # PL now also declares these, with different URLs, so
490 # the code notices those attributes already existed with
491 # different values, and complains.
492 # This happens regularly on delegation now that PG and
493 # PL both declare the namespace with different URLs.
494 # If the content ever differs this is a problem,
495 # but for now it works - different URLs (values in the attributes)
496 # but the same actual schema, so using the PG schema
497 # on delegated-to-PL credentials works fine.
499 # Note: you could also not copy attributes
500 # which already exist. It appears that both PG and PL
501 # will actually validate a slicecred with a parent
502 # signed using PG namespaces and a child signed with PL
503 # namespaces over the whole thing. But I don't know
504 # if that is a bug in xmlsec1, an accident since
505 # the contents of the schemas are the same,
506 # or something else, but it seems odd. And this works.
507 parentRoot = sdoc.documentElement
508 if parentRoot.tagName == "signed-credential" and parentRoot.hasAttributes():
509 for attrIx in range(0, parentRoot.attributes.length):
510 attr = parentRoot.attributes.item(attrIx)
511 # returns the old attribute of same name that was
513 # Below throws InUse exception if we forgot to clone the attribute first
514 oldAttr = signed_cred.setAttributeNode(attr.cloneNode(True))
515 if oldAttr and oldAttr.value != attr.value:
516 msg = "Delegating cred from owner %s to %s over %s:\n - Replaced attribute %s value '%s' with '%s'" % (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" % (self.get_summary_tostring(), self.expiration.strftime(SFATIME_FORMAT)))
804 # Verify the signatures
805 filename = self.save_to_random_tmp_file()
806 if trusted_certs is not None:
807 cert_args = " ".join(['--trusted-pem %s' % x for x in trusted_certs])
809 # If caller explicitly passed in None that means skip cert chain validation.
810 # - Strange and not typical
811 if trusted_certs is not None:
812 # Verify the gids of this cred and of its parents
813 for cur_cred in self.get_credential_list():
814 cur_cred.get_gid_object().verify_chain(trusted_cert_objects)
815 cur_cred.get_gid_caller().verify_chain(trusted_cert_objects)
818 refs.append("Sig_%s" % self.get_refid())
820 parentRefs = self.updateRefID()
821 for ref in parentRefs:
822 refs.append("Sig_%s" % ref)
825 # If caller explicitly passed in None that means skip xmlsec1 validation.
826 # Strange and not typical
827 if trusted_certs is None:
830 # print "Doing %s --verify --node-id '%s' %s %s 2>&1" % \
831 # (self.xmlsec_path, ref, cert_args, filename)
832 verified = os.popen('%s --verify --node-id "%s" %s %s 2>&1' \
833 % (self.xmlsec_path, ref, cert_args, filename)).read()
834 if not verified.strip().startswith("OK"):
835 # xmlsec errors have a msg= which is the interesting bit.
836 mstart = verified.find("msg=")
838 if mstart > -1 and len(verified) > 4:
840 mend = verified.find('\\', mstart)
841 msg = verified[mstart:mend]
842 raise CredentialNotVerifiable("xmlsec1 error verifying cred %s using Signature ID %s: %s %s" % (self.get_summary_tostring(), ref, msg, verified.strip()))
845 # Verify the parents (delegation)
847 self.verify_parent(self.parent)
849 # Make sure the issuer is the target's authority, and is
851 self.verify_issuer(trusted_cert_objects)
855 # Creates a list of the credential and its parents, with the root
856 # (original delegated credential) as the last item in the list
857 def get_credential_list(self):
861 list.append(cur_cred)
863 cur_cred = cur_cred.parent
869 # Make sure the credential's target gid (a) was signed by or (b)
870 # is the same as the entity that signed the original credential,
871 # or (c) is an authority over the target's namespace.
872 # Also ensure that the credential issuer / signer itself has a valid
873 # GID signature chain (signed by an authority with namespace rights).
874 def verify_issuer(self, trusted_gids):
875 root_cred = self.get_credential_list()[-1]
876 root_target_gid = root_cred.get_gid_object()
877 root_cred_signer = root_cred.get_signature().get_issuer_gid()
880 # Allow non authority to sign target and cred about target.
882 # Why do we need to allow non authorities to sign?
883 # If in the target gid validation step we correctly
884 # checked that the target is only signed by an authority,
885 # then this is just a special case of case 3.
886 # This short-circuit is the common case currently -
887 # and cause GID validation doesn't check 'authority',
888 # this allows users to generate valid slice credentials.
889 if root_target_gid.is_signed_by_cert(root_cred_signer):
890 # cred signer matches target signer, return success
894 # Allow someone to sign credential about themeselves. Used?
895 # If not, remove this.
896 #root_target_gid_str = root_target_gid.save_to_string()
897 #root_cred_signer_str = root_cred_signer.save_to_string()
898 #if root_target_gid_str == root_cred_signer_str:
899 # # cred signer is target, return success
904 # root_cred_signer is not the target_gid
905 # So this is a different gid that we have not verified.
906 # xmlsec1 verified the cert chain on this already, but
907 # it hasn't verified that the gid meets the HRN namespace
909 # Below we'll ensure that it is an authority.
910 # But we haven't verified that it is _signed by_ an authority
911 # We also don't know if xmlsec1 requires that cert signers
914 # Note that if verify() gave us no trusted_gids then this
915 # call will fail. So skip it if we have no trusted_gids
916 if trusted_gids and len(trusted_gids) > 0:
917 root_cred_signer.verify_chain(trusted_gids)
919 logger.debug("No trusted gids. Cannot verify that cred signer is signed by a trusted authority. Skipping that check.")
921 # See if the signer is an authority over the domain of the target.
922 # There are multiple types of authority - accept them all here
923 # Maybe should be (hrn, type) = urn_to_hrn(root_cred_signer.get_urn())
924 root_cred_signer_type = root_cred_signer.get_type()
925 if (root_cred_signer_type.find('authority') == 0):
926 #logger.debug('Cred signer is an authority')
927 # signer is an authority, see if target is in authority's domain
928 signerhrn = root_cred_signer.get_hrn()
929 if hrn_authfor_hrn(signerhrn, root_target_gid.get_hrn()):
932 # We've required that the credential be signed by an authority
933 # for that domain. Reasonable and probably correct.
934 # A looser model would also allow the signer to be an authority
935 # in my control framework - eg My CA or CH. Even if it is not
936 # the CH that issued these, eg, user credentials.
938 # Give up, credential does not pass issuer verification
940 raise CredentialNotVerifiable("Could not verify credential owned by %s for object %s. Cred signer %s not the trusted authority for Cred target %s" % (self.gidCaller.get_urn(), self.gidObject.get_urn(), root_cred_signer.get_hrn(), root_target_gid.get_hrn()))
944 # -- For Delegates (credentials with parents) verify that:
945 # . The privileges must be a subset of the parent credentials
946 # . The privileges must have "can_delegate" set for each delegated privilege
947 # . The target gid must be the same between child and parents
948 # . The expiry time on the child must be no later than the parent
949 # . The signer of the child must be the owner of the parent
950 def verify_parent(self, parent_cred):
951 # make sure the rights given to the child are a subset of the
952 # parents rights (and check delegate bits)
953 if not parent_cred.get_privileges().is_superset(self.get_privileges()):
954 raise ChildRightsNotSubsetOfParent(("Parent cred ref %s rights " % parent_cred.get_refid()) +
955 self.parent.get_privileges().save_to_string() + (" not superset of delegated cred %s ref %s rights " % (self.get_summary_tostring(), self.get_refid())) +
956 self.get_privileges().save_to_string())
958 # make sure my target gid is the same as the parent's
959 if not parent_cred.get_gid_object().save_to_string() == \
960 self.get_gid_object().save_to_string():
961 raise CredentialNotVerifiable("Delegated cred %s: Target gid not equal between parent and child. Parent %s" % (self.get_summary_tostring(), parent_cred.get_summary_tostring()))
963 # make sure my expiry time is <= my parent's
964 if not parent_cred.get_expiration() >= self.get_expiration():
965 raise CredentialNotVerifiable("Delegated credential %s expires after parent %s" % (self.get_summary_tostring(), parent_cred.get_summary_tostring()))
967 # make sure my signer is the parent's caller
968 if not parent_cred.get_gid_caller().save_to_string(False) == \
969 self.get_signature().get_issuer_gid().save_to_string(False):
970 raise CredentialNotVerifiable("Delegated credential %s not signed by parent %s's caller" % (self.get_summary_tostring(), parent_cred.get_summary_tostring()))
973 if parent_cred.parent:
974 parent_cred.verify_parent(parent_cred.parent)
977 def delegate(self, delegee_gidfile, caller_keyfile, caller_gidfile):
979 Return a delegated copy of this credential, delegated to the
980 specified gid's user.
982 # get the gid of the object we are delegating
983 object_gid = self.get_gid_object()
984 object_hrn = object_gid.get_hrn()
986 # the hrn of the user who will be delegated to
987 delegee_gid = GID(filename=delegee_gidfile)
988 delegee_hrn = delegee_gid.get_hrn()
990 #user_key = Keypair(filename=keyfile)
991 #user_hrn = self.get_gid_caller().get_hrn()
992 subject_string = "%s delegated to %s" % (object_hrn, delegee_hrn)
993 dcred = Credential(subject=subject_string)
994 dcred.set_gid_caller(delegee_gid)
995 dcred.set_gid_object(object_gid)
996 dcred.set_parent(self)
997 dcred.set_expiration(self.get_expiration())
998 dcred.set_privileges(self.get_privileges())
999 dcred.get_privileges().delegate_all_privileges(True)
1000 #dcred.set_issuer_keys(keyfile, delegee_gidfile)
1001 dcred.set_issuer_keys(caller_keyfile, caller_gidfile)
1008 def get_filename(self):
1009 return getattr(self,'filename',None)
1011 def actual_caller_hrn (self):
1012 """a helper method used by some API calls like e.g. Allocate
1013 to try and find out who really is the original caller
1015 This admittedly is a bit of a hack, please USE IN LAST RESORT
1017 This code uses a heuristic to identify a delegated credential
1019 A first known restriction if for traffic that gets through a slice manager
1020 in this case the hrn reported is the one from the last SM in the call graph
1021 which is not at all what is meant here"""
1023 caller_hrn = self.get_gid_caller().get_hrn()
1024 issuer_hrn = self.get_signature().get_issuer_gid().get_hrn()
1025 subject_hrn = self.get_gid_object().get_hrn()
1026 # if we find that the caller_hrn is an immediate descendant of the issuer, then
1027 # this seems to be a 'regular' credential
1028 if caller_hrn.startswith(issuer_hrn):
1029 actual_caller_hrn=caller_hrn
1030 # else this looks like a delegated credential, and the real caller is the issuer
1032 actual_caller_hrn=issuer_hrn
1033 logger.info("actual_caller_hrn: caller_hrn=%s, issuer_hrn=%s, returning %s"%(caller_hrn,issuer_hrn,actual_caller_hrn))
1034 return actual_caller_hrn
1037 # Dump the contents of a credential to stdout in human-readable format
1039 # @param dump_parents If true, also dump the parent certificates
1040 def dump (self, *args, **kwargs):
1041 print self.dump_string(*args, **kwargs)
1043 # show_xml is ignored
1044 def dump_string(self, dump_parents=False, show_xml=None):
1046 result += "CREDENTIAL %s\n" % self.get_subject()
1047 filename=self.get_filename()
1048 if filename: result += "Filename %s\n"%filename
1049 privileges = self.get_privileges()
1051 result += " privs: %s\n" % privileges.save_to_string()
1053 result += " privs: \n"
1054 gidCaller = self.get_gid_caller()
1056 result += " gidCaller:\n"
1057 result += gidCaller.dump_string(8, dump_parents)
1059 if self.get_signature():
1061 self.get_signature().get_issuer_gid().dump(8, dump_parents)
1064 print " expiration:", self.expiration.strftime(SFATIME_FORMAT)
1066 gidObject = self.get_gid_object()
1068 result += " gidObject:\n"
1069 result += gidObject.dump_string(8, dump_parents)
1071 if self.parent and dump_parents:
1072 result += "\nPARENT"
1073 result += self.parent.dump_string(True)