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.sfalogging import sfa_logger
39 from sfa.trust.certificate import Keypair
40 from sfa.trust.credential_legacy import CredentialLegacy
41 from sfa.trust.rights import *
42 from sfa.trust.gid import *
43 from sfa.util.faults import *
48 # Two years, in seconds
49 DEFAULT_CREDENTIAL_LIFETIME = 60 * 60 * 24 * 365 * 2
53 # . make privs match between PG and PL
54 # . Need to add support for other types of credentials, e.g. tickets
57 signature_template = \
59 <Signature xml:id="Sig_%s" xmlns="http://www.w3.org/2000/09/xmldsig#">
61 <CanonicalizationMethod Algorithm="http://www.w3.org/TR/2001/REC-xml-c14n-20010315"/>
62 <SignatureMethod Algorithm="http://www.w3.org/2000/09/xmldsig#rsa-sha1"/>
65 <Transform Algorithm="http://www.w3.org/2000/09/xmldsig#enveloped-signature" />
67 <DigestMethod Algorithm="http://www.w3.org/2000/09/xmldsig#sha1"/>
68 <DigestValue></DigestValue>
84 # Convert a string into a bool
87 if str.lower() in ['yes','true','1']:
93 # Utility function to get the text of an XML element
95 def getTextNode(element, subele):
96 sub = element.getElementsByTagName(subele)[0]
97 if len(sub.childNodes) > 0:
98 return sub.childNodes[0].nodeValue
103 # Utility function to set the text of an XML element
104 # It creates the element, adds the text to it,
105 # and then appends it to the parent.
107 def append_sub(doc, parent, element, text):
108 ele = doc.createElement(element)
109 ele.appendChild(doc.createTextNode(text))
110 parent.appendChild(ele)
113 # Signature contains information about an xmlsec1 signature
114 # for a signed-credential
117 class Signature(object):
119 def __init__(self, string=None):
121 self.issuer_gid = None
138 def set_refid(self, id):
141 def get_issuer_gid(self):
146 def set_issuer_gid(self, gid):
150 doc = parseString(self.xml)
151 sig = doc.getElementsByTagName("Signature")[0]
152 self.set_refid(sig.getAttribute("xml:id").strip("Sig_"))
153 keyinfo = sig.getElementsByTagName("X509Data")[0]
154 szgid = getTextNode(keyinfo, "X509Certificate")
155 szgid = "-----BEGIN CERTIFICATE-----\n%s\n-----END CERTIFICATE-----" % szgid
156 self.set_issuer_gid(GID(string=szgid))
159 self.xml = signature_template % (self.get_refid(), self.get_refid())
163 # A credential provides a caller gid with privileges to an object gid.
164 # A signed credential is signed by the object's authority.
166 # Credentials are encoded in one of two ways. The legacy style places
167 # it in the subjectAltName of an X509 certificate. The new credentials
168 # are placed in signed XML.
171 # In general, a signed credential obtained externally should
172 # not be changed else the signature is no longer valid. So, once
173 # you have loaded an existing signed credential, do not call encode() or sign() on it.
175 def filter_creds_by_caller(creds, caller_hrn):
177 Returns a list of creds who's gid caller matches the
180 if not isinstance(creds, list): creds = [creds]
184 tmp_cred = Credential(string=cred)
185 if tmp_cred.get_gid_caller().get_hrn() == caller_hrn:
186 caller_creds.append(cred)
190 class Credential(object):
193 # Create a Credential object
195 # @param create If true, create a blank x509 certificate
196 # @param subject If subject!=None, create an x509 cert with the subject name
197 # @param string If string!=None, load the credential from the string
198 # @param filename If filename!=None, load the credential from the file
199 # FIXME: create and subject are ignored!
200 def __init__(self, create=False, subject=None, string=None, filename=None):
201 self.gidCaller = None
202 self.gidObject = None
203 self.expiration = None
204 self.privileges = None
205 self.issuer_privkey = None
206 self.issuer_gid = None
207 self.issuer_pubkey = None
209 self.signature = None
214 # Check if this is a legacy credential, translate it if so
215 if string or filename:
219 str = file(filename).read()
221 if str.strip().startswith("-----"):
222 self.legacy = CredentialLegacy(False,string=str)
223 self.translate_legacy(str)
228 # Find an xmlsec1 path
229 self.xmlsec_path = ''
230 paths = ['/usr/bin','/usr/local/bin','/bin','/opt/bin','/opt/local/bin']
232 if os.path.isfile(path + '/' + 'xmlsec1'):
233 self.xmlsec_path = path + '/' + 'xmlsec1'
236 def get_subject(self):
237 if not self.gidObject:
239 return self.gidObject.get_subject()
241 def get_signature(self):
242 if not self.signature:
244 return self.signature
246 def set_signature(self, sig):
251 # Translate a legacy credential into a new one
253 # @param String of the legacy credential
255 def translate_legacy(self, str):
256 legacy = CredentialLegacy(False,string=str)
257 self.gidCaller = legacy.get_gid_caller()
258 self.gidObject = legacy.get_gid_object()
259 lifetime = legacy.get_lifetime()
261 # Default to two years
262 self.set_lifetime(DEFAULT_CREDENTIAL_LIFETIME)
264 self.set_lifetime(int(lifetime))
265 self.lifeTime = legacy.get_lifetime()
266 self.set_privileges(legacy.get_privileges())
267 self.get_privileges().delegate_all_privileges(legacy.get_delegate())
270 # Need the issuer's private key and name
271 # @param key Keypair object containing the private key of the issuer
272 # @param gid GID of the issuing authority
274 def set_issuer_keys(self, privkey, gid):
275 self.issuer_privkey = privkey
276 self.issuer_gid = gid
280 # Set this credential's parent
281 def set_parent(self, cred):
286 # set the GID of the caller
288 # @param gid GID object of the caller
290 def set_gid_caller(self, gid):
292 # gid origin caller is the caller's gid by default
293 self.gidOriginCaller = gid
296 # get the GID of the object
298 def get_gid_caller(self):
299 if not self.gidCaller:
301 return self.gidCaller
304 # set the GID of the object
306 # @param gid GID object of the object
308 def set_gid_object(self, gid):
312 # get the GID of the object
314 def get_gid_object(self):
315 if not self.gidObject:
317 return self.gidObject
320 # set the lifetime of this credential
322 # @param lifetime lifetime of credential
323 # . if lifeTime is a datetime object, it is used for the expiration time
324 # . if lifeTime is an integer value, it is considered the number of seconds
325 # remaining before expiration
327 def set_lifetime(self, lifeTime):
328 if isinstance(lifeTime, int):
329 self.expiration = datetime.timedelta(seconds=lifeTime) + datetime.datetime.utcnow()
331 self.expiration = lifeTime
334 # get the lifetime of the credential (in datetime format)
336 def get_lifetime(self):
337 if not self.expiration:
339 return self.expiration
345 # @param privs either a comma-separated list of privileges of a RightList object
347 def set_privileges(self, privs):
348 if isinstance(privs, str):
349 self.privileges = RightList(string = privs)
351 self.privileges = privs
355 # return the privileges as a RightList object
357 def get_privileges(self):
358 if not self.privileges:
360 return self.privileges
363 # determine whether the credential allows a particular operation to be
366 # @param op_name string specifying name of operation ("lookup", "update", etc)
368 def can_perform(self, op_name):
369 rights = self.get_privileges()
374 return rights.can_perform(op_name)
378 # Encode the attributes of the credential into an XML string
379 # This should be done immediately before signing the credential.
381 # In general, a signed credential obtained externally should
382 # not be changed else the signature is no longer valid. So, once
383 # you have loaded an existing signed credential, do not call encode() or sign() on it.
386 # Create the XML document
388 signed_cred = doc.createElement("signed-credential")
389 doc.appendChild(signed_cred)
391 # Fill in the <credential> bit
392 cred = doc.createElement("credential")
393 cred.setAttribute("xml:id", self.get_refid())
394 signed_cred.appendChild(cred)
395 append_sub(doc, cred, "type", "privilege")
396 append_sub(doc, cred, "serial", "8")
397 append_sub(doc, cred, "owner_gid", self.gidCaller.save_to_string())
398 append_sub(doc, cred, "owner_urn", self.gidCaller.get_urn())
399 append_sub(doc, cred, "target_gid", self.gidObject.save_to_string())
400 append_sub(doc, cred, "target_urn", self.gidObject.get_urn())
401 append_sub(doc, cred, "uuid", "")
402 if not self.expiration:
403 self.set_lifetime(DEFAULT_CREDENTIAL_LIFETIME)
404 self.expiration = self.expiration.replace(microsecond=0)
405 append_sub(doc, cred, "expires", self.expiration.isoformat())
406 privileges = doc.createElement("privileges")
407 cred.appendChild(privileges)
410 rights = self.get_privileges()
411 for right in rights.rights:
412 priv = doc.createElement("privilege")
413 append_sub(doc, priv, "name", right.kind)
414 append_sub(doc, priv, "can_delegate", str(right.delegate).lower())
415 privileges.appendChild(priv)
417 # Add the parent credential if it exists
419 sdoc = parseString(self.parent.get_xml())
420 p_cred = doc.importNode(sdoc.getElementsByTagName("credential")[0], True)
421 p = doc.createElement("parent")
422 p.appendChild(p_cred)
426 # Create the <signatures> tag
427 signatures = doc.createElement("signatures")
428 signed_cred.appendChild(signatures)
430 # Add any parent signatures
432 for cur_cred in self.get_credential_list()[1:]:
433 sdoc = parseString(cur_cred.get_signature().get_xml())
434 ele = doc.importNode(sdoc.getElementsByTagName("Signature")[0], True)
435 signatures.appendChild(ele)
437 # Get the finished product
438 self.xml = doc.toxml()
441 def save_to_random_tmp_file(self):
442 fp, filename = mkstemp(suffix='cred', text=True)
443 fp = os.fdopen(fp, "w")
444 self.save_to_file(filename, save_parents=True, filep=fp)
447 def save_to_file(self, filename, save_parents=True, filep=None):
453 f = open(filename, "w")
457 def save_to_string(self, save_parents=True):
467 def set_refid(self, rid):
471 # Figure out what refids exist, and update this credential's id
472 # so that it doesn't clobber the others. Returns the refids of
475 def updateRefID(self):
477 self.set_refid('ref0')
482 next_cred = self.parent
484 refs.append(next_cred.get_refid())
486 next_cred = next_cred.parent
491 # Find a unique refid for this credential
492 rid = self.get_refid()
495 rid = "ref%d" % (val + 1)
500 # Return the set of parent credential ref ids
509 # Sign the XML file created by encode()
512 # In general, a signed credential obtained externally should
513 # not be changed else the signature is no longer valid. So, once
514 # you have loaded an existing signed credential, do not call encode() or sign() on it.
517 if not self.issuer_privkey or not self.issuer_gid:
519 doc = parseString(self.get_xml())
520 sigs = doc.getElementsByTagName("signatures")[0]
522 # Create the signature template to be signed
523 signature = Signature()
524 signature.set_refid(self.get_refid())
525 sdoc = parseString(signature.get_xml())
526 sig_ele = doc.importNode(sdoc.getElementsByTagName("Signature")[0], True)
527 sigs.appendChild(sig_ele)
529 self.xml = doc.toxml()
532 # Split the issuer GID into multiple certificates if it's a chain
533 chain = GID(filename=self.issuer_gid)
536 gid_files.append(chain.save_to_random_tmp_file(False))
537 if chain.get_parent():
538 chain = chain.get_parent()
543 # Call out to xmlsec1 to sign it
544 ref = 'Sig_%s' % self.get_refid()
545 filename = self.save_to_random_tmp_file()
546 signed = os.popen('%s --sign --node-id "%s" --privkey-pem %s,%s %s' \
547 % (self.xmlsec_path, ref, self.issuer_privkey, ",".join(gid_files), filename)).read()
550 for gid_file in gid_files:
555 # This is no longer a legacy credential
564 # Retrieve the attributes of the credential from the XML.
565 # This is automatically called by the various get_* methods of
566 # this class and should not need to be called explicitly.
571 doc = parseString(self.xml)
573 signed_cred = doc.getElementsByTagName("signed-credential")
575 # Is this a signed-cred or just a cred?
576 if len(signed_cred) > 0:
577 cred = signed_cred[0].getElementsByTagName("credential")[0]
578 signatures = signed_cred[0].getElementsByTagName("signatures")
579 if len(signatures) > 0:
580 sigs = signatures[0].getElementsByTagName("Signature")
582 cred = doc.getElementsByTagName("credential")[0]
585 self.set_refid(cred.getAttribute("xml:id"))
586 self.set_lifetime(parse(getTextNode(cred, "expires")))
587 self.gidCaller = GID(string=getTextNode(cred, "owner_gid"))
588 self.gidObject = GID(string=getTextNode(cred, "target_gid"))
592 privs = cred.getElementsByTagName("privileges")[0]
594 for priv in privs.getElementsByTagName("privilege"):
595 kind = getTextNode(priv, "name")
596 deleg = str2bool(getTextNode(priv, "can_delegate"))
598 # Convert * into the default privileges for the credential's type
599 _ , type = urn_to_hrn(self.gidObject.get_urn())
600 rl = rlist.determine_rights(type, self.gidObject.get_urn())
604 rlist.add(Right(kind.strip(), deleg))
605 self.set_privileges(rlist)
609 parent = cred.getElementsByTagName("parent")
611 parent_doc = parent[0].getElementsByTagName("credential")[0]
612 parent_xml = parent_doc.toxml()
613 self.parent = Credential(string=parent_xml)
616 # Assign the signatures to the credentials
618 Sig = Signature(string=sig.toxml())
620 for cur_cred in self.get_credential_list():
621 if cur_cred.get_refid() == Sig.get_refid():
622 cur_cred.set_signature(Sig)
627 # trusted_certs: A list of trusted GID filenames (not GID objects!)
628 # Chaining is not supported within the GIDs by xmlsec1.
631 # . All of the signatures are valid and that the issuers trace back
632 # to trusted roots (performed by xmlsec1)
633 # . The XML matches the credential schema
634 # . That the issuer of the credential is the authority in the target's urn
635 # . In the case of a delegated credential, this must be true of the root
636 # . That all of the gids presented in the credential are valid
637 # . The credential is not expired
639 # -- For Delegates (credentials with parents)
640 # . The privileges must be a subset of the parent credentials
641 # . The privileges must have "can_delegate" set for each delegated privilege
642 # . The target gid must be the same between child and parents
643 # . The expiry time on the child must be no later than the parent
644 # . The signer of the child must be the owner of the parent
646 # -- Verify does *NOT*
647 # . ensure that an xmlrpc client's gid matches a credential gid, that
648 # must be done elsewhere
650 # @param trusted_certs: The certificates of trusted CA certificates
651 def verify(self, trusted_certs):
655 # trusted_cert_objects = [GID(filename=f) for f in trusted_certs]
656 trusted_cert_objects = []
657 ok_trusted_certs = []
658 for f in trusted_certs:
660 # Failures here include unreadable files
662 trusted_cert_objects.append(GID(filename=f))
663 ok_trusted_certs.append(f)
664 except Exception, exc:
665 sfa_logger.error("Failed to load trusted cert from %s: %r", f, exc)
666 trusted_certs = ok_trusted_certs
668 # Use legacy verification if this is a legacy credential
670 self.legacy.verify_chain(trusted_cert_objects)
671 if self.legacy.client_gid:
672 self.legacy.client_gid.verify_chain(trusted_cert_objects)
673 if self.legacy.object_gid:
674 self.legacy.object_gid.verify_chain(trusted_cert_objects)
677 # make sure it is not expired
678 if self.get_lifetime() < datetime.datetime.utcnow():
679 raise CredentialNotVerifiable("Credential expired at %s" % self.expiration.isoformat())
681 # Verify the signatures
682 filename = self.save_to_random_tmp_file()
683 cert_args = " ".join(['--trusted-pem %s' % x for x in trusted_certs])
685 # Verify the gids of this cred and of its parents
686 for cur_cred in self.get_credential_list():
687 cur_cred.get_gid_object().verify_chain(trusted_cert_objects)
688 cur_cred.get_gid_caller().verify_chain(trusted_cert_objects)
691 refs.append("Sig_%s" % self.get_refid())
693 parentRefs = self.updateRefID()
694 for ref in parentRefs:
695 refs.append("Sig_%s" % ref)
698 verified = os.popen('%s --verify --node-id "%s" %s %s 2>&1' \
699 % (self.xmlsec_path, ref, cert_args, filename)).read()
700 if not verified.strip().startswith("OK"):
701 raise CredentialNotVerifiable("xmlsec1 error verifying cert: " + verified)
704 # Verify the parents (delegation)
706 self.verify_parent(self.parent)
708 # Make sure the issuer is the target's authority
713 # Creates a list of the credential and its parents, with the root
714 # (original delegated credential) as the last item in the list
715 def get_credential_list(self):
719 list.append(cur_cred)
721 cur_cred = cur_cred.parent
727 # Make sure the credential's target gid was signed by (or is the same) the entity that signed
728 # the original credential or an authority over that namespace.
729 def verify_issuer(self):
730 root_cred = self.get_credential_list()[-1]
731 root_target_gid = root_cred.get_gid_object()
732 root_cred_signer = root_cred.get_signature().get_issuer_gid()
734 if root_target_gid.is_signed_by_cert(root_cred_signer):
735 # cred signer matches target signer, return success
738 root_target_gid_str = root_target_gid.save_to_string()
739 root_cred_signer_str = root_cred_signer.save_to_string()
740 if root_target_gid_str == root_cred_signer_str:
741 # cred signer is target, return success
744 # See if it the signer is an authority over the domain of the target
745 # Maybe should be (hrn, type) = urn_to_hrn(root_cred_signer.get_urn())
746 root_cred_signer_type = root_cred_signer.get_type()
747 if (root_cred_signer_type == 'authority'):
748 #sfa_logger.debug('Cred signer is an authority')
749 # signer is an authority, see if target is in authority's domain
750 hrn = root_cred_signer.get_hrn()
751 if root_target_gid.get_hrn().startswith(hrn):
754 # We've required that the credential be signed by an authority
755 # for that domain. Reasonable and probably correct.
756 # A looser model would also allow the signer to be an authority
757 # in my control framework - eg My CA or CH. Even if it is not
758 # the CH that issued these, eg, user credentials.
760 # Give up, credential does not pass issuer verification
762 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()))
766 # -- For Delegates (credentials with parents) verify that:
767 # . The privileges must be a subset of the parent credentials
768 # . The privileges must have "can_delegate" set for each delegated privilege
769 # . The target gid must be the same between child and parents
770 # . The expiry time on the child must be no later than the parent
771 # . The signer of the child must be the owner of the parent
772 def verify_parent(self, parent_cred):
773 # make sure the rights given to the child are a subset of the
774 # parents rights (and check delegate bits)
775 if not parent_cred.get_privileges().is_superset(self.get_privileges()):
776 raise ChildRightsNotSubsetOfParent(
777 self.parent.get_privileges().save_to_string() + " " +
778 self.get_privileges().save_to_string())
780 # make sure my target gid is the same as the parent's
781 if not parent_cred.get_gid_object().save_to_string() == \
782 self.get_gid_object().save_to_string():
783 raise CredentialNotVerifiable("Target gid not equal between parent and child")
785 # make sure my expiry time is <= my parent's
786 if not parent_cred.get_lifetime() >= self.get_lifetime():
787 raise CredentialNotVerifiable("Delegated credential expires after parent")
789 # make sure my signer is the parent's caller
790 if not parent_cred.get_gid_caller().save_to_string(False) == \
791 self.get_signature().get_issuer_gid().save_to_string(False):
792 raise CredentialNotVerifiable("Delegated credential not signed by parent caller")
795 if parent_cred.parent:
796 parent_cred.verify_parent(parent_cred.parent)
799 def delegate(self, delegee_gidfile, caller_keyfile, caller_gidfile):
801 Return a delegated copy of this credential, delegated to the
802 specified gid's user.
804 # get the gid of the object we are delegating
805 object_gid = self.get_gid_object()
806 object_hrn = object_gid.get_hrn()
808 # the hrn of the user who will be delegated to
809 delegee_gid = GID(filename=delegee_gidfile)
810 delegee_hrn = delegee_gid.get_hrn()
812 #user_key = Keypair(filename=keyfile)
813 #user_hrn = self.get_gid_caller().get_hrn()
814 subject_string = "%s delegated to %s" % (object_hrn, delegee_hrn)
815 dcred = Credential(subject=subject_string)
816 dcred.set_gid_caller(delegee_gid)
817 dcred.set_gid_object(object_gid)
818 dcred.set_parent(self)
819 dcred.set_lifetime(self.get_lifetime())
820 dcred.set_privileges(self.get_privileges())
821 dcred.get_privileges().delegate_all_privileges(True)
822 #dcred.set_issuer_keys(keyfile, delegee_gidfile)
823 dcred.set_issuer_keys(caller_keyfile, caller_gidfile)
829 # Dump the contents of a credential to stdout in human-readable format
831 # @param dump_parents If true, also dump the parent certificates
833 def dump(self, dump_parents=False):
834 print "CREDENTIAL", self.get_subject()
836 print " privs:", self.get_privileges().save_to_string()
839 gidCaller = self.get_gid_caller()
841 gidCaller.dump(8, dump_parents)
844 gidObject = self.get_gid_object()
846 gidObject.dump(8, dump_parents)
849 if self.parent and dump_parents:
851 self.parent.dump_parents()