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'" % (self.parent.gidCaller.get_urn(), self.gidCaller.get_urn(), self.gidObject.get_urn(), oldAttr.name, oldAttr.value, attr.value)
517 #raise CredentialNotVerifiable("Can't encode new valid delegated credential: %s" % msg)
519 p_cred = doc.importNode(sdoc.getElementsByTagName("credential")[0], True)
520 p = doc.createElement("parent")
521 p.appendChild(p_cred)
523 # done handling parent credential
525 # Create the <signatures> tag
526 signatures = doc.createElement("signatures")
527 signed_cred.appendChild(signatures)
529 # Add any parent signatures
531 for cur_cred in self.get_credential_list()[1:]:
532 sdoc = parseString(cur_cred.get_signature().get_xml())
533 ele = doc.importNode(sdoc.getElementsByTagName("Signature")[0], True)
534 signatures.appendChild(ele)
536 # Get the finished product
537 self.xml = doc.toxml()
540 def save_to_random_tmp_file(self):
541 fp, filename = mkstemp(suffix='cred', text=True)
542 fp = os.fdopen(fp, "w")
543 self.save_to_file(filename, save_parents=True, filep=fp)
546 def save_to_file(self, filename, save_parents=True, filep=None):
552 f = open(filename, "w")
556 def save_to_string(self, save_parents=True):
566 def set_refid(self, rid):
570 # Figure out what refids exist, and update this credential's id
571 # so that it doesn't clobber the others. Returns the refids of
574 def updateRefID(self):
576 self.set_refid('ref0')
581 next_cred = self.parent
583 refs.append(next_cred.get_refid())
585 next_cred = next_cred.parent
590 # Find a unique refid for this credential
591 rid = self.get_refid()
594 rid = "ref%d" % (val + 1)
599 # Return the set of parent credential ref ids
608 # Sign the XML file created by encode()
611 # In general, a signed credential obtained externally should
612 # not be changed else the signature is no longer valid. So, once
613 # you have loaded an existing signed credential, do not call encode() or sign() on it.
616 if not self.issuer_privkey or not self.issuer_gid:
618 doc = parseString(self.get_xml())
619 sigs = doc.getElementsByTagName("signatures")[0]
621 # Create the signature template to be signed
622 signature = Signature()
623 signature.set_refid(self.get_refid())
624 sdoc = parseString(signature.get_xml())
625 sig_ele = doc.importNode(sdoc.getElementsByTagName("Signature")[0], True)
626 sigs.appendChild(sig_ele)
628 self.xml = doc.toxml()
631 # Split the issuer GID into multiple certificates if it's a chain
632 chain = GID(filename=self.issuer_gid)
635 gid_files.append(chain.save_to_random_tmp_file(False))
636 if chain.get_parent():
637 chain = chain.get_parent()
642 # Call out to xmlsec1 to sign it
643 ref = 'Sig_%s' % self.get_refid()
644 filename = self.save_to_random_tmp_file()
645 signed = os.popen('%s --sign --node-id "%s" --privkey-pem %s,%s %s' \
646 % (self.xmlsec_path, ref, self.issuer_privkey, ",".join(gid_files), filename)).read()
649 for gid_file in gid_files:
659 # Retrieve the attributes of the credential from the XML.
660 # This is automatically called by the various get_* methods of
661 # this class and should not need to be called explicitly.
669 doc = parseString(self.xml)
671 raise CredentialNotVerifiable("Malformed credential")
672 doc = parseString(self.xml)
674 signed_cred = doc.getElementsByTagName("signed-credential")
676 # Is this a signed-cred or just a cred?
677 if len(signed_cred) > 0:
678 creds = signed_cred[0].getElementsByTagName("credential")
679 signatures = signed_cred[0].getElementsByTagName("signatures")
680 if len(signatures) > 0:
681 sigs = signatures[0].getElementsByTagName("Signature")
683 creds = doc.getElementsByTagName("credential")
685 if creds is None or len(creds) == 0:
686 # malformed cred file
687 raise CredentialNotVerifiable("Malformed XML: No credential tag found")
689 # Just take the first cred if there are more than one
692 self.set_refid(cred.getAttribute("xml:id"))
693 self.set_expiration(utcparse(getTextNode(cred, "expires")))
694 self.gidCaller = GID(string=getTextNode(cred, "owner_gid"))
695 self.gidObject = GID(string=getTextNode(cred, "target_gid"))
699 privs = cred.getElementsByTagName("privileges")[0]
701 for priv in privs.getElementsByTagName("privilege"):
702 kind = getTextNode(priv, "name")
703 deleg = str2bool(getTextNode(priv, "can_delegate"))
705 # Convert * into the default privileges for the credential's type
706 # Each inherits the delegatability from the * above
707 _ , type = urn_to_hrn(self.gidObject.get_urn())
708 rl = determine_rights(type, self.gidObject.get_urn())
713 rlist.add(Right(kind.strip(), deleg))
714 self.set_privileges(rlist)
718 parent = cred.getElementsByTagName("parent")
720 parent_doc = parent[0].getElementsByTagName("credential")[0]
721 parent_xml = parent_doc.toxml()
722 self.parent = Credential(string=parent_xml)
725 # Assign the signatures to the credentials
727 Sig = Signature(string=sig.toxml())
729 for cur_cred in self.get_credential_list():
730 if cur_cred.get_refid() == Sig.get_refid():
731 cur_cred.set_signature(Sig)
736 # trusted_certs: A list of trusted GID filenames (not GID objects!)
737 # Chaining is not supported within the GIDs by xmlsec1.
739 # trusted_certs_required: Should usually be true. Set False means an
740 # empty list of trusted_certs would still let this method pass.
741 # It just skips xmlsec1 verification et al. Only used by some utils
744 # . All of the signatures are valid and that the issuers trace back
745 # to trusted roots (performed by xmlsec1)
746 # . The XML matches the credential schema
747 # . That the issuer of the credential is the authority in the target's urn
748 # . In the case of a delegated credential, this must be true of the root
749 # . That all of the gids presented in the credential are valid
750 # . Including verifying GID chains, and includ the issuer
751 # . The credential is not expired
753 # -- For Delegates (credentials with parents)
754 # . The privileges must be a subset of the parent credentials
755 # . The privileges must have "can_delegate" set for each delegated privilege
756 # . The target gid must be the same between child and parents
757 # . The expiry time on the child must be no later than the parent
758 # . The signer of the child must be the owner of the parent
760 # -- Verify does *NOT*
761 # . ensure that an xmlrpc client's gid matches a credential gid, that
762 # must be done elsewhere
764 # @param trusted_certs: The certificates of trusted CA certificates
765 def verify(self, trusted_certs=None, schema=None, trusted_certs_required=True):
769 # validate against RelaxNG schema
771 if schema and os.path.exists(schema):
772 tree = etree.parse(StringIO(self.xml))
773 schema_doc = etree.parse(schema)
774 xmlschema = etree.XMLSchema(schema_doc)
775 if not xmlschema.validate(tree):
776 error = xmlschema.error_log.last_error
777 message = "%s: %s (line %s)" % (self.get_summary_tostring(), error.message, error.line)
778 raise CredentialNotVerifiable(message)
780 if trusted_certs_required and trusted_certs is None:
783 # trusted_cert_objects = [GID(filename=f) for f in trusted_certs]
784 trusted_cert_objects = []
785 ok_trusted_certs = []
786 # If caller explicitly passed in None that means skip cert chain validation.
787 # Strange and not typical
788 if trusted_certs is not None:
789 for f in trusted_certs:
791 # Failures here include unreadable files
793 trusted_cert_objects.append(GID(filename=f))
794 ok_trusted_certs.append(f)
795 except Exception, exc:
796 logger.error("Failed to load trusted cert from %s: %r"%( f, exc))
797 trusted_certs = ok_trusted_certs
799 # make sure it is not expired
800 if self.get_expiration() < datetime.datetime.utcnow():
801 raise CredentialNotVerifiable("Credential %s expired at %s" % (self.get_summary_tostring(), self.expiration.strftime(SFATIME_FORMAT)))
803 # Verify the signatures
804 filename = self.save_to_random_tmp_file()
805 if trusted_certs is not None:
806 cert_args = " ".join(['--trusted-pem %s' % x for x in trusted_certs])
808 # If caller explicitly passed in None that means skip cert chain validation.
809 # - Strange and not typical
810 if trusted_certs is not None:
811 # Verify the gids of this cred and of its parents
812 for cur_cred in self.get_credential_list():
813 cur_cred.get_gid_object().verify_chain(trusted_cert_objects)
814 cur_cred.get_gid_caller().verify_chain(trusted_cert_objects)
817 refs.append("Sig_%s" % self.get_refid())
819 parentRefs = self.updateRefID()
820 for ref in parentRefs:
821 refs.append("Sig_%s" % ref)
824 # If caller explicitly passed in None that means skip xmlsec1 validation.
825 # Strange and not typical
826 if trusted_certs is None:
829 # print "Doing %s --verify --node-id '%s' %s %s 2>&1" % \
830 # (self.xmlsec_path, ref, cert_args, filename)
831 verified = os.popen('%s --verify --node-id "%s" %s %s 2>&1' \
832 % (self.xmlsec_path, ref, cert_args, filename)).read()
833 if not verified.strip().startswith("OK"):
834 # xmlsec errors have a msg= which is the interesting bit.
835 mstart = verified.find("msg=")
837 if mstart > -1 and len(verified) > 4:
839 mend = verified.find('\\', mstart)
840 msg = verified[mstart:mend]
841 raise CredentialNotVerifiable("xmlsec1 error verifying cred %s using Signature ID %s: %s %s" % (self.get_summary_tostring(), ref, msg, verified.strip()))
844 # Verify the parents (delegation)
846 self.verify_parent(self.parent)
848 # Make sure the issuer is the target's authority, and is
850 self.verify_issuer(trusted_cert_objects)
854 # Creates a list of the credential and its parents, with the root
855 # (original delegated credential) as the last item in the list
856 def get_credential_list(self):
860 list.append(cur_cred)
862 cur_cred = cur_cred.parent
868 # Make sure the credential's target gid (a) was signed by or (b)
869 # is the same as the entity that signed the original credential,
870 # or (c) is an authority over the target's namespace.
871 # Also ensure that the credential issuer / signer itself has a valid
872 # GID signature chain (signed by an authority with namespace rights).
873 def verify_issuer(self, trusted_gids):
874 root_cred = self.get_credential_list()[-1]
875 root_target_gid = root_cred.get_gid_object()
876 root_cred_signer = root_cred.get_signature().get_issuer_gid()
879 # Allow non authority to sign target and cred about target.
881 # Why do we need to allow non authorities to sign?
882 # If in the target gid validation step we correctly
883 # checked that the target is only signed by an authority,
884 # then this is just a special case of case 3.
885 # This short-circuit is the common case currently -
886 # and cause GID validation doesn't check 'authority',
887 # this allows users to generate valid slice credentials.
888 if root_target_gid.is_signed_by_cert(root_cred_signer):
889 # cred signer matches target signer, return success
893 # Allow someone to sign credential about themeselves. Used?
894 # If not, remove this.
895 #root_target_gid_str = root_target_gid.save_to_string()
896 #root_cred_signer_str = root_cred_signer.save_to_string()
897 #if root_target_gid_str == root_cred_signer_str:
898 # # cred signer is target, return success
903 # root_cred_signer is not the target_gid
904 # So this is a different gid that we have not verified.
905 # xmlsec1 verified the cert chain on this already, but
906 # it hasn't verified that the gid meets the HRN namespace
908 # Below we'll ensure that it is an authority.
909 # But we haven't verified that it is _signed by_ an authority
910 # We also don't know if xmlsec1 requires that cert signers
913 # Note that if verify() gave us no trusted_gids then this
914 # call will fail. So skip it if we have no trusted_gids
915 if trusted_gids and len(trusted_gids) > 0:
916 root_cred_signer.verify_chain(trusted_gids)
918 logger.debug("No trusted gids. Cannot verify that cred signer is signed by a trusted authority. Skipping that check.")
920 # See if the signer is an authority over the domain of the target.
921 # There are multiple types of authority - accept them all here
922 # Maybe should be (hrn, type) = urn_to_hrn(root_cred_signer.get_urn())
923 root_cred_signer_type = root_cred_signer.get_type()
924 if (root_cred_signer_type.find('authority') == 0):
925 #logger.debug('Cred signer is an authority')
926 # signer is an authority, see if target is in authority's domain
927 signerhrn = root_cred_signer.get_hrn()
928 if hrn_authfor_hrn(signerhrn, root_target_gid.get_hrn()):
931 # We've required that the credential be signed by an authority
932 # for that domain. Reasonable and probably correct.
933 # A looser model would also allow the signer to be an authority
934 # in my control framework - eg My CA or CH. Even if it is not
935 # the CH that issued these, eg, user credentials.
937 # Give up, credential does not pass issuer verification
939 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()))
943 # -- For Delegates (credentials with parents) verify that:
944 # . The privileges must be a subset of the parent credentials
945 # . The privileges must have "can_delegate" set for each delegated privilege
946 # . The target gid must be the same between child and parents
947 # . The expiry time on the child must be no later than the parent
948 # . The signer of the child must be the owner of the parent
949 def verify_parent(self, parent_cred):
950 # make sure the rights given to the child are a subset of the
951 # parents rights (and check delegate bits)
952 if not parent_cred.get_privileges().is_superset(self.get_privileges()):
953 raise ChildRightsNotSubsetOfParent(("Parent cred ref %s rights " % parent_cred.get_refid()) +
954 self.parent.get_privileges().save_to_string() + (" not superset of delegated cred %s ref %s rights " % (self.get_summary_tostring(), self.get_refid())) +
955 self.get_privileges().save_to_string())
957 # make sure my target gid is the same as the parent's
958 if not parent_cred.get_gid_object().save_to_string() == \
959 self.get_gid_object().save_to_string():
960 raise CredentialNotVerifiable("Delegated cred %s: Target gid not equal between parent and child. Parent %s" % (self.get_summary_tostring(), parent_cred.get_summary_tostring()))
962 # make sure my expiry time is <= my parent's
963 if not parent_cred.get_expiration() >= self.get_expiration():
964 raise CredentialNotVerifiable("Delegated credential %s expires after parent %s" % (self.get_summary_tostring(), parent_cred.get_summary_tostring()))
966 # make sure my signer is the parent's caller
967 if not parent_cred.get_gid_caller().save_to_string(False) == \
968 self.get_signature().get_issuer_gid().save_to_string(False):
969 raise CredentialNotVerifiable("Delegated credential %s not signed by parent %s's caller" % (self.get_summary_tostring(), parent_cred.get_summary_tostring()))
972 if parent_cred.parent:
973 parent_cred.verify_parent(parent_cred.parent)
976 def delegate(self, delegee_gidfile, caller_keyfile, caller_gidfile):
978 Return a delegated copy of this credential, delegated to the
979 specified gid's user.
981 # get the gid of the object we are delegating
982 object_gid = self.get_gid_object()
983 object_hrn = object_gid.get_hrn()
985 # the hrn of the user who will be delegated to
986 delegee_gid = GID(filename=delegee_gidfile)
987 delegee_hrn = delegee_gid.get_hrn()
989 #user_key = Keypair(filename=keyfile)
990 #user_hrn = self.get_gid_caller().get_hrn()
991 subject_string = "%s delegated to %s" % (object_hrn, delegee_hrn)
992 dcred = Credential(subject=subject_string)
993 dcred.set_gid_caller(delegee_gid)
994 dcred.set_gid_object(object_gid)
995 dcred.set_parent(self)
996 dcred.set_expiration(self.get_expiration())
997 dcred.set_privileges(self.get_privileges())
998 dcred.get_privileges().delegate_all_privileges(True)
999 #dcred.set_issuer_keys(keyfile, delegee_gidfile)
1000 dcred.set_issuer_keys(caller_keyfile, caller_gidfile)
1007 def get_filename(self):
1008 return getattr(self,'filename',None)
1010 def actual_caller_hrn (self):
1011 """a helper method used by some API calls like e.g. Allocate
1012 to try and find out who really is the original caller
1014 This admittedly is a bit of a hack, please USE IN LAST RESORT
1016 This code uses a heuristic to identify a delegated credential
1018 A first known restriction if for traffic that gets through a slice manager
1019 in this case the hrn reported is the one from the last SM in the call graph
1020 which is not at all what is meant here"""
1022 caller_hrn = self.get_gid_caller().get_hrn()
1023 issuer_hrn = self.get_signature().get_issuer_gid().get_hrn()
1024 subject_hrn = self.get_gid_object().get_hrn()
1025 # if we find that the caller_hrn is an immediate descendant of the issuer, then
1026 # this seems to be a 'regular' credential
1027 if caller_hrn.startswith(issuer_hrn):
1028 actual_caller_hrn=caller_hrn
1029 # else this looks like a delegated credential, and the real caller is the issuer
1031 actual_caller_hrn=issuer_hrn
1032 logger.info("actual_caller_hrn: caller_hrn=%s, issuer_hrn=%s, returning %s"%(caller_hrn,issuer_hrn,actual_caller_hrn))
1033 return actual_caller_hrn
1036 # Dump the contents of a credential to stdout in human-readable format
1038 # @param dump_parents If true, also dump the parent certificates
1039 def dump (self, *args, **kwargs):
1040 print self.dump_string(*args, **kwargs)
1042 # show_xml is ignored
1043 def dump_string(self, dump_parents=False, show_xml=None):
1045 result += "CREDENTIAL %s\n" % self.get_subject()
1046 filename=self.get_filename()
1047 if filename: result += "Filename %s\n"%filename
1048 privileges = self.get_privileges()
1050 result += " privs: %s\n" % privileges.save_to_string()
1052 result += " privs: \n"
1053 gidCaller = self.get_gid_caller()
1055 result += " gidCaller:\n"
1056 result += gidCaller.dump_string(8, dump_parents)
1058 if self.get_signature():
1060 self.get_signature().get_issuer_gid().dump(8, dump_parents)
1063 print " expiration:", self.expiration.strftime(SFATIME_FORMAT)
1065 gidObject = self.get_gid_object()
1067 result += " gidObject:\n"
1068 result += gidObject.dump_string(8, dump_parents)
1070 if self.parent and dump_parents:
1071 result += "\nPARENT"
1072 result += self.parent.dump_string(True)