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
34 from tempfile import mkstemp
35 from xml.dom.minidom import Document, parseString
36 from dateutil.parser import parse
38 from sfa.util.faults import *
39 from sfa.util.sfalogging import sfa_logger
40 from sfa.trust.certificate import Keypair
41 from sfa.trust.credential_legacy import CredentialLegacy
42 from sfa.trust.rights import Right, Rights
43 from sfa.trust.gid import GID
45 # Two years, in seconds
46 DEFAULT_CREDENTIAL_LIFETIME = 60 * 60 * 24 * 365 * 2
50 # . make privs match between PG and PL
51 # . Need to add support for other types of credentials, e.g. tickets
54 signature_template = \
56 <Signature xml:id="Sig_%s" xmlns="http://www.w3.org/2000/09/xmldsig#">
58 <CanonicalizationMethod Algorithm="http://www.w3.org/TR/2001/REC-xml-c14n-20010315"/>
59 <SignatureMethod Algorithm="http://www.w3.org/2000/09/xmldsig#rsa-sha1"/>
62 <Transform Algorithm="http://www.w3.org/2000/09/xmldsig#enveloped-signature" />
64 <DigestMethod Algorithm="http://www.w3.org/2000/09/xmldsig#sha1"/>
65 <DigestValue></DigestValue>
81 # Convert a string into a bool
84 if str.lower() in ['yes','true','1']:
90 # Utility function to get the text of an XML element
92 def getTextNode(element, subele):
93 sub = element.getElementsByTagName(subele)[0]
94 if len(sub.childNodes) > 0:
95 return sub.childNodes[0].nodeValue
100 # Utility function to set the text of an XML element
101 # It creates the element, adds the text to it,
102 # and then appends it to the parent.
104 def append_sub(doc, parent, element, text):
105 ele = doc.createElement(element)
106 ele.appendChild(doc.createTextNode(text))
107 parent.appendChild(ele)
110 # Signature contains information about an xmlsec1 signature
111 # for a signed-credential
114 class Signature(object):
116 def __init__(self, string=None):
118 self.issuer_gid = None
135 def set_refid(self, id):
138 def get_issuer_gid(self):
143 def set_issuer_gid(self, gid):
147 doc = parseString(self.xml)
148 sig = doc.getElementsByTagName("Signature")[0]
149 self.set_refid(sig.getAttribute("xml:id").strip("Sig_"))
150 keyinfo = sig.getElementsByTagName("X509Data")[0]
151 szgid = getTextNode(keyinfo, "X509Certificate")
152 szgid = "-----BEGIN CERTIFICATE-----\n%s\n-----END CERTIFICATE-----" % szgid
153 self.set_issuer_gid(GID(string=szgid))
156 self.xml = signature_template % (self.get_refid(), self.get_refid())
160 # A credential provides a caller gid with privileges to an object gid.
161 # A signed credential is signed by the object's authority.
163 # Credentials are encoded in one of two ways. The legacy style places
164 # it in the subjectAltName of an X509 certificate. The new credentials
165 # are placed in signed XML.
168 # In general, a signed credential obtained externally should
169 # not be changed else the signature is no longer valid. So, once
170 # you have loaded an existing signed credential, do not call encode() or sign() on it.
172 def filter_creds_by_caller(creds, caller_hrn):
174 Returns a list of creds who's gid caller matches the
177 if not isinstance(creds, list): creds = [creds]
181 tmp_cred = Credential(string=cred)
182 if tmp_cred.get_gid_caller().get_hrn() == caller_hrn:
183 caller_creds.append(cred)
187 class Credential(object):
190 # Create a Credential object
192 # @param create If true, create a blank x509 certificate
193 # @param subject If subject!=None, create an x509 cert with the subject name
194 # @param string If string!=None, load the credential from the string
195 # @param filename If filename!=None, load the credential from the file
196 # FIXME: create and subject are ignored!
197 def __init__(self, create=False, subject=None, string=None, filename=None):
198 self.gidCaller = None
199 self.gidObject = None
200 self.expiration = None
201 self.privileges = None
202 self.issuer_privkey = None
203 self.issuer_gid = None
204 self.issuer_pubkey = None
206 self.signature = None
211 # Check if this is a legacy credential, translate it if so
212 if string or filename:
216 str = file(filename).read()
218 if str.strip().startswith("-----"):
219 self.legacy = CredentialLegacy(False,string=str)
220 self.translate_legacy(str)
225 # Find an xmlsec1 path
226 self.xmlsec_path = ''
227 paths = ['/usr/bin','/usr/local/bin','/bin','/opt/bin','/opt/local/bin']
229 if os.path.isfile(path + '/' + 'xmlsec1'):
230 self.xmlsec_path = path + '/' + 'xmlsec1'
233 def get_subject(self):
234 if not self.gidObject:
236 return self.gidObject.get_subject()
238 def get_signature(self):
239 if not self.signature:
241 return self.signature
243 def set_signature(self, sig):
248 # Translate a legacy credential into a new one
250 # @param String of the legacy credential
252 def translate_legacy(self, str):
253 legacy = CredentialLegacy(False,string=str)
254 self.gidCaller = legacy.get_gid_caller()
255 self.gidObject = legacy.get_gid_object()
256 lifetime = legacy.get_lifetime()
258 # Default to two years
259 self.set_lifetime(DEFAULT_CREDENTIAL_LIFETIME)
261 self.set_lifetime(int(lifetime))
262 self.lifeTime = legacy.get_lifetime()
263 self.set_privileges(legacy.get_privileges())
264 self.get_privileges().delegate_all_privileges(legacy.get_delegate())
267 # Need the issuer's private key and name
268 # @param key Keypair object containing the private key of the issuer
269 # @param gid GID of the issuing authority
271 def set_issuer_keys(self, privkey, gid):
272 self.issuer_privkey = privkey
273 self.issuer_gid = gid
277 # Set this credential's parent
278 def set_parent(self, cred):
283 # set the GID of the caller
285 # @param gid GID object of the caller
287 def set_gid_caller(self, gid):
289 # gid origin caller is the caller's gid by default
290 self.gidOriginCaller = gid
293 # get the GID of the object
295 def get_gid_caller(self):
296 if not self.gidCaller:
298 return self.gidCaller
301 # set the GID of the object
303 # @param gid GID object of the object
305 def set_gid_object(self, gid):
309 # get the GID of the object
311 def get_gid_object(self):
312 if not self.gidObject:
314 return self.gidObject
317 # set the lifetime of this credential
319 # @param lifetime lifetime of credential
320 # . if lifeTime is a datetime object, it is used for the expiration time
321 # . if lifeTime is an integer value, it is considered the number of seconds
322 # remaining before expiration
324 def set_lifetime(self, lifeTime):
325 if isinstance(lifeTime, int):
326 self.expiration = datetime.timedelta(seconds=lifeTime) + datetime.datetime.utcnow()
328 self.expiration = lifeTime
331 # get the lifetime of the credential (in datetime format)
333 def get_lifetime(self):
334 if not self.expiration:
336 return self.expiration
342 # @param privs either a comma-separated list of privileges of a Rights object
344 def set_privileges(self, privs):
345 if isinstance(privs, str):
346 self.privileges = Rights(string = privs)
348 self.privileges = privs
352 # return the privileges as a Rights object
354 def get_privileges(self):
355 if not self.privileges:
357 return self.privileges
360 # determine whether the credential allows a particular operation to be
363 # @param op_name string specifying name of operation ("lookup", "update", etc)
365 def can_perform(self, op_name):
366 rights = self.get_privileges()
371 return rights.can_perform(op_name)
375 # Encode the attributes of the credential into an XML string
376 # This should be done immediately before signing the credential.
378 # In general, a signed credential obtained externally should
379 # not be changed else the signature is no longer valid. So, once
380 # you have loaded an existing signed credential, do not call encode() or sign() on it.
383 # Create the XML document
385 signed_cred = doc.createElement("signed-credential")
386 doc.appendChild(signed_cred)
388 # Fill in the <credential> bit
389 cred = doc.createElement("credential")
390 cred.setAttribute("xml:id", self.get_refid())
391 signed_cred.appendChild(cred)
392 append_sub(doc, cred, "type", "privilege")
393 append_sub(doc, cred, "serial", "8")
394 append_sub(doc, cred, "owner_gid", self.gidCaller.save_to_string())
395 append_sub(doc, cred, "owner_urn", self.gidCaller.get_urn())
396 append_sub(doc, cred, "target_gid", self.gidObject.save_to_string())
397 append_sub(doc, cred, "target_urn", self.gidObject.get_urn())
398 append_sub(doc, cred, "uuid", "")
399 if not self.expiration:
400 self.set_lifetime(DEFAULT_CREDENTIAL_LIFETIME)
401 self.expiration = self.expiration.replace(microsecond=0)
402 append_sub(doc, cred, "expires", self.expiration.isoformat())
403 privileges = doc.createElement("privileges")
404 cred.appendChild(privileges)
407 rights = self.get_privileges()
408 for right in rights.rights:
409 priv = doc.createElement("privilege")
410 append_sub(doc, priv, "name", right.kind)
411 append_sub(doc, priv, "can_delegate", str(right.delegate).lower())
412 privileges.appendChild(priv)
414 # Add the parent credential if it exists
416 sdoc = parseString(self.parent.get_xml())
417 p_cred = doc.importNode(sdoc.getElementsByTagName("credential")[0], True)
418 p = doc.createElement("parent")
419 p.appendChild(p_cred)
423 # Create the <signatures> tag
424 signatures = doc.createElement("signatures")
425 signed_cred.appendChild(signatures)
427 # Add any parent signatures
429 for cur_cred in self.get_credential_list()[1:]:
430 sdoc = parseString(cur_cred.get_signature().get_xml())
431 ele = doc.importNode(sdoc.getElementsByTagName("Signature")[0], True)
432 signatures.appendChild(ele)
434 # Get the finished product
435 self.xml = doc.toxml()
438 def save_to_random_tmp_file(self):
439 fp, filename = mkstemp(suffix='cred', text=True)
440 fp = os.fdopen(fp, "w")
441 self.save_to_file(filename, save_parents=True, filep=fp)
444 def save_to_file(self, filename, save_parents=True, filep=None):
450 f = open(filename, "w")
454 def save_to_string(self, save_parents=True):
464 def set_refid(self, rid):
468 # Figure out what refids exist, and update this credential's id
469 # so that it doesn't clobber the others. Returns the refids of
472 def updateRefID(self):
474 self.set_refid('ref0')
479 next_cred = self.parent
481 refs.append(next_cred.get_refid())
483 next_cred = next_cred.parent
488 # Find a unique refid for this credential
489 rid = self.get_refid()
492 rid = "ref%d" % (val + 1)
497 # Return the set of parent credential ref ids
506 # Sign the XML file created by encode()
509 # In general, a signed credential obtained externally should
510 # not be changed else the signature is no longer valid. So, once
511 # you have loaded an existing signed credential, do not call encode() or sign() on it.
514 if not self.issuer_privkey or not self.issuer_gid:
516 doc = parseString(self.get_xml())
517 sigs = doc.getElementsByTagName("signatures")[0]
519 # Create the signature template to be signed
520 signature = Signature()
521 signature.set_refid(self.get_refid())
522 sdoc = parseString(signature.get_xml())
523 sig_ele = doc.importNode(sdoc.getElementsByTagName("Signature")[0], True)
524 sigs.appendChild(sig_ele)
526 self.xml = doc.toxml()
529 # Split the issuer GID into multiple certificates if it's a chain
530 chain = GID(filename=self.issuer_gid)
533 gid_files.append(chain.save_to_random_tmp_file(False))
534 if chain.get_parent():
535 chain = chain.get_parent()
540 # Call out to xmlsec1 to sign it
541 ref = 'Sig_%s' % self.get_refid()
542 filename = self.save_to_random_tmp_file()
543 signed = os.popen('%s --sign --node-id "%s" --privkey-pem %s,%s %s' \
544 % (self.xmlsec_path, ref, self.issuer_privkey, ",".join(gid_files), filename)).read()
547 for gid_file in gid_files:
552 # This is no longer a legacy credential
561 # Retrieve the attributes of the credential from the XML.
562 # This is automatically called by the various get_* methods of
563 # this class and should not need to be called explicitly.
568 doc = parseString(self.xml)
570 signed_cred = doc.getElementsByTagName("signed-credential")
572 # Is this a signed-cred or just a cred?
573 if len(signed_cred) > 0:
574 cred = signed_cred[0].getElementsByTagName("credential")[0]
575 signatures = signed_cred[0].getElementsByTagName("signatures")
576 if len(signatures) > 0:
577 sigs = signatures[0].getElementsByTagName("Signature")
579 cred = doc.getElementsByTagName("credential")[0]
582 self.set_refid(cred.getAttribute("xml:id"))
583 self.set_lifetime(parse(getTextNode(cred, "expires")))
584 self.gidCaller = GID(string=getTextNode(cred, "owner_gid"))
585 self.gidObject = GID(string=getTextNode(cred, "target_gid"))
589 privs = cred.getElementsByTagName("privileges")[0]
591 for priv in privs.getElementsByTagName("privilege"):
592 kind = getTextNode(priv, "name")
593 deleg = str2bool(getTextNode(priv, "can_delegate"))
595 # Convert * into the default privileges for the credential's type
596 _ , type = urn_to_hrn(self.gidObject.get_urn())
597 rl = rlist.determine_rights(type, self.gidObject.get_urn())
601 rlist.add(Right(kind.strip(), deleg))
602 self.set_privileges(rlist)
606 parent = cred.getElementsByTagName("parent")
608 parent_doc = parent[0].getElementsByTagName("credential")[0]
609 parent_xml = parent_doc.toxml()
610 self.parent = Credential(string=parent_xml)
613 # Assign the signatures to the credentials
615 Sig = Signature(string=sig.toxml())
617 for cur_cred in self.get_credential_list():
618 if cur_cred.get_refid() == Sig.get_refid():
619 cur_cred.set_signature(Sig)
624 # trusted_certs: A list of trusted GID filenames (not GID objects!)
625 # Chaining is not supported within the GIDs by xmlsec1.
628 # . All of the signatures are valid and that the issuers trace back
629 # to trusted roots (performed by xmlsec1)
630 # . The XML matches the credential schema
631 # . That the issuer of the credential is the authority in the target's urn
632 # . In the case of a delegated credential, this must be true of the root
633 # . That all of the gids presented in the credential are valid
634 # . The credential is not expired
636 # -- For Delegates (credentials with parents)
637 # . The privileges must be a subset of the parent credentials
638 # . The privileges must have "can_delegate" set for each delegated privilege
639 # . The target gid must be the same between child and parents
640 # . The expiry time on the child must be no later than the parent
641 # . The signer of the child must be the owner of the parent
643 # -- Verify does *NOT*
644 # . ensure that an xmlrpc client's gid matches a credential gid, that
645 # must be done elsewhere
647 # @param trusted_certs: The certificates of trusted CA certificates
648 def verify(self, trusted_certs):
652 # trusted_cert_objects = [GID(filename=f) for f in trusted_certs]
653 trusted_cert_objects = []
654 ok_trusted_certs = []
655 for f in trusted_certs:
657 # Failures here include unreadable files
659 trusted_cert_objects.append(GID(filename=f))
660 ok_trusted_certs.append(f)
661 except Exception, exc:
662 sfa_logger.error("Failed to load trusted cert from %s: %r", f, exc)
663 trusted_certs = ok_trusted_certs
665 # Use legacy verification if this is a legacy credential
667 self.legacy.verify_chain(trusted_cert_objects)
668 if self.legacy.client_gid:
669 self.legacy.client_gid.verify_chain(trusted_cert_objects)
670 if self.legacy.object_gid:
671 self.legacy.object_gid.verify_chain(trusted_cert_objects)
674 # make sure it is not expired
675 if self.get_lifetime() < datetime.datetime.utcnow():
676 raise CredentialNotVerifiable("Credential expired at %s" % self.expiration.isoformat())
678 # Verify the signatures
679 filename = self.save_to_random_tmp_file()
680 cert_args = " ".join(['--trusted-pem %s' % x for x in trusted_certs])
682 # Verify the gids of this cred and of its parents
683 for cur_cred in self.get_credential_list():
684 cur_cred.get_gid_object().verify_chain(trusted_cert_objects)
685 cur_cred.get_gid_caller().verify_chain(trusted_cert_objects)
688 refs.append("Sig_%s" % self.get_refid())
690 parentRefs = self.updateRefID()
691 for ref in parentRefs:
692 refs.append("Sig_%s" % ref)
695 verified = os.popen('%s --verify --node-id "%s" %s %s 2>&1' \
696 % (self.xmlsec_path, ref, cert_args, filename)).read()
697 if not verified.strip().startswith("OK"):
698 raise CredentialNotVerifiable("xmlsec1 error verifying cert: " + verified)
701 # Verify the parents (delegation)
703 self.verify_parent(self.parent)
705 # Make sure the issuer is the target's authority
710 # Creates a list of the credential and its parents, with the root
711 # (original delegated credential) as the last item in the list
712 def get_credential_list(self):
716 list.append(cur_cred)
718 cur_cred = cur_cred.parent
724 # Make sure the credential's target gid was signed by (or is the same) the entity that signed
725 # the original credential or an authority over that namespace.
726 def verify_issuer(self):
727 root_cred = self.get_credential_list()[-1]
728 root_target_gid = root_cred.get_gid_object()
729 root_cred_signer = root_cred.get_signature().get_issuer_gid()
731 if root_target_gid.is_signed_by_cert(root_cred_signer):
732 # cred signer matches target signer, return success
735 root_target_gid_str = root_target_gid.save_to_string()
736 root_cred_signer_str = root_cred_signer.save_to_string()
737 if root_target_gid_str == root_cred_signer_str:
738 # cred signer is target, return success
741 # See if it the signer is an authority over the domain of the target
742 # Maybe should be (hrn, type) = urn_to_hrn(root_cred_signer.get_urn())
743 root_cred_signer_type = root_cred_signer.get_type()
744 if (root_cred_signer_type == 'authority'):
745 #sfa_logger.debug('Cred signer is an authority')
746 # signer is an authority, see if target is in authority's domain
747 hrn = root_cred_signer.get_hrn()
748 if root_target_gid.get_hrn().startswith(hrn):
751 # We've required that the credential be signed by an authority
752 # for that domain. Reasonable and probably correct.
753 # A looser model would also allow the signer to be an authority
754 # in my control framework - eg My CA or CH. Even if it is not
755 # the CH that issued these, eg, user credentials.
757 # Give up, credential does not pass issuer verification
759 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()))
763 # -- For Delegates (credentials with parents) verify that:
764 # . The privileges must be a subset of the parent credentials
765 # . The privileges must have "can_delegate" set for each delegated privilege
766 # . The target gid must be the same between child and parents
767 # . The expiry time on the child must be no later than the parent
768 # . The signer of the child must be the owner of the parent
769 def verify_parent(self, parent_cred):
770 # make sure the rights given to the child are a subset of the
771 # parents rights (and check delegate bits)
772 if not parent_cred.get_privileges().is_superset(self.get_privileges()):
773 raise ChildRightsNotSubsetOfParent(
774 self.parent.get_privileges().save_to_string() + " " +
775 self.get_privileges().save_to_string())
777 # make sure my target gid is the same as the parent's
778 if not parent_cred.get_gid_object().save_to_string() == \
779 self.get_gid_object().save_to_string():
780 raise CredentialNotVerifiable("Target gid not equal between parent and child")
782 # make sure my expiry time is <= my parent's
783 if not parent_cred.get_lifetime() >= self.get_lifetime():
784 raise CredentialNotVerifiable("Delegated credential expires after parent")
786 # make sure my signer is the parent's caller
787 if not parent_cred.get_gid_caller().save_to_string(False) == \
788 self.get_signature().get_issuer_gid().save_to_string(False):
789 raise CredentialNotVerifiable("Delegated credential not signed by parent caller")
792 if parent_cred.parent:
793 parent_cred.verify_parent(parent_cred.parent)
796 def delegate(self, delegee_gidfile, caller_keyfile, caller_gidfile):
798 Return a delegated copy of this credential, delegated to the
799 specified gid's user.
801 # get the gid of the object we are delegating
802 object_gid = self.get_gid_object()
803 object_hrn = object_gid.get_hrn()
805 # the hrn of the user who will be delegated to
806 delegee_gid = GID(filename=delegee_gidfile)
807 delegee_hrn = delegee_gid.get_hrn()
809 #user_key = Keypair(filename=keyfile)
810 #user_hrn = self.get_gid_caller().get_hrn()
811 subject_string = "%s delegated to %s" % (object_hrn, delegee_hrn)
812 dcred = Credential(subject=subject_string)
813 dcred.set_gid_caller(delegee_gid)
814 dcred.set_gid_object(object_gid)
815 dcred.set_parent(self)
816 dcred.set_lifetime(self.get_lifetime())
817 dcred.set_privileges(self.get_privileges())
818 dcred.get_privileges().delegate_all_privileges(True)
819 #dcred.set_issuer_keys(keyfile, delegee_gidfile)
820 dcred.set_issuer_keys(caller_keyfile, caller_gidfile)
826 # Dump the contents of a credential to stdout in human-readable format
828 # @param dump_parents If true, also dump the parent certificates
830 def dump(self, dump_parents=False):
831 print "CREDENTIAL", self.get_subject()
833 print " privs:", self.get_privileges().save_to_string()
836 gidCaller = self.get_gid_caller()
838 gidCaller.dump(8, dump_parents)
841 gidObject = self.get_gid_object()
843 gidObject.dump(8, dump_parents)
846 if self.parent and dump_parents:
848 self.parent.dump_parents()