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
44 from sfa.util.namespace import *
46 # Two years, in seconds
47 DEFAULT_CREDENTIAL_LIFETIME = 60 * 60 * 24 * 365 * 2
51 # . make privs match between PG and PL
52 # . Need to add support for other types of credentials, e.g. tickets
55 signature_template = \
57 <Signature xml:id="Sig_%s" xmlns="http://www.w3.org/2000/09/xmldsig#">
59 <CanonicalizationMethod Algorithm="http://www.w3.org/TR/2001/REC-xml-c14n-20010315"/>
60 <SignatureMethod Algorithm="http://www.w3.org/2000/09/xmldsig#rsa-sha1"/>
63 <Transform Algorithm="http://www.w3.org/2000/09/xmldsig#enveloped-signature" />
65 <DigestMethod Algorithm="http://www.w3.org/2000/09/xmldsig#sha1"/>
66 <DigestValue></DigestValue>
82 # Convert a string into a bool
85 if str.lower() in ['yes','true','1']:
91 # Utility function to get the text of an XML element
93 def getTextNode(element, subele):
94 sub = element.getElementsByTagName(subele)[0]
95 if len(sub.childNodes) > 0:
96 return sub.childNodes[0].nodeValue
101 # Utility function to set the text of an XML element
102 # It creates the element, adds the text to it,
103 # and then appends it to the parent.
105 def append_sub(doc, parent, element, text):
106 ele = doc.createElement(element)
107 ele.appendChild(doc.createTextNode(text))
108 parent.appendChild(ele)
111 # Signature contains information about an xmlsec1 signature
112 # for a signed-credential
115 class Signature(object):
117 def __init__(self, string=None):
119 self.issuer_gid = None
136 def set_refid(self, id):
139 def get_issuer_gid(self):
144 def set_issuer_gid(self, gid):
148 doc = parseString(self.xml)
149 sig = doc.getElementsByTagName("Signature")[0]
150 self.set_refid(sig.getAttribute("xml:id").strip("Sig_"))
151 keyinfo = sig.getElementsByTagName("X509Data")[0]
152 szgid = getTextNode(keyinfo, "X509Certificate")
153 szgid = "-----BEGIN CERTIFICATE-----\n%s\n-----END CERTIFICATE-----" % szgid
154 self.set_issuer_gid(GID(string=szgid))
157 self.xml = signature_template % (self.get_refid(), self.get_refid())
161 # A credential provides a caller gid with privileges to an object gid.
162 # A signed credential is signed by the object's authority.
164 # Credentials are encoded in one of two ways. The legacy style places
165 # it in the subjectAltName of an X509 certificate. The new credentials
166 # are placed in signed XML.
169 # In general, a signed credential obtained externally should
170 # not be changed else the signature is no longer valid. So, once
171 # you have loaded an existing signed credential, do not call encode() or sign() on it.
173 def filter_creds_by_caller(creds, caller_hrn):
175 Returns a list of creds who's gid caller matches the
178 if not isinstance(creds, list): creds = [creds]
182 tmp_cred = Credential(string=cred)
183 if tmp_cred.get_gid_caller().get_hrn() == caller_hrn:
184 caller_creds.append(cred)
188 class Credential(object):
191 # Create a Credential object
193 # @param create If true, create a blank x509 certificate
194 # @param subject If subject!=None, create an x509 cert with the subject name
195 # @param string If string!=None, load the credential from the string
196 # @param filename If filename!=None, load the credential from the file
197 # FIXME: create and subject are ignored!
198 def __init__(self, create=False, subject=None, string=None, filename=None):
199 self.gidCaller = None
200 self.gidObject = None
201 self.expiration = None
202 self.privileges = None
203 self.issuer_privkey = None
204 self.issuer_gid = None
205 self.issuer_pubkey = None
207 self.signature = None
212 # Check if this is a legacy credential, translate it if so
213 if string or filename:
217 str = file(filename).read()
219 if str.strip().startswith("-----"):
220 self.legacy = CredentialLegacy(False,string=str)
221 self.translate_legacy(str)
226 # Find an xmlsec1 path
227 self.xmlsec_path = ''
228 paths = ['/usr/bin','/usr/local/bin','/bin','/opt/bin','/opt/local/bin']
230 if os.path.isfile(path + '/' + 'xmlsec1'):
231 self.xmlsec_path = path + '/' + 'xmlsec1'
234 def get_subject(self):
235 if not self.gidObject:
237 return self.gidObject.get_subject()
239 def get_signature(self):
240 if not self.signature:
242 return self.signature
244 def set_signature(self, sig):
249 # Translate a legacy credential into a new one
251 # @param String of the legacy credential
253 def translate_legacy(self, str):
254 legacy = CredentialLegacy(False,string=str)
255 self.gidCaller = legacy.get_gid_caller()
256 self.gidObject = legacy.get_gid_object()
257 lifetime = legacy.get_lifetime()
259 # Default to two years
260 self.set_lifetime(DEFAULT_CREDENTIAL_LIFETIME)
262 self.set_lifetime(int(lifetime))
263 self.lifeTime = legacy.get_lifetime()
264 self.set_privileges(legacy.get_privileges())
265 self.get_privileges().delegate_all_privileges(legacy.get_delegate())
268 # Need the issuer's private key and name
269 # @param key Keypair object containing the private key of the issuer
270 # @param gid GID of the issuing authority
272 def set_issuer_keys(self, privkey, gid):
273 self.issuer_privkey = privkey
274 self.issuer_gid = gid
278 # Set this credential's parent
279 def set_parent(self, cred):
284 # set the GID of the caller
286 # @param gid GID object of the caller
288 def set_gid_caller(self, gid):
290 # gid origin caller is the caller's gid by default
291 self.gidOriginCaller = gid
294 # get the GID of the object
296 def get_gid_caller(self):
297 if not self.gidCaller:
299 return self.gidCaller
302 # set the GID of the object
304 # @param gid GID object of the object
306 def set_gid_object(self, gid):
310 # get the GID of the object
312 def get_gid_object(self):
313 if not self.gidObject:
315 return self.gidObject
318 # set the lifetime of this credential
320 # @param lifetime lifetime of credential
321 # . if lifeTime is a datetime object, it is used for the expiration time
322 # . if lifeTime is an integer value, it is considered the number of seconds
323 # remaining before expiration
325 def set_lifetime(self, lifeTime):
326 if isinstance(lifeTime, int):
327 self.expiration = datetime.timedelta(seconds=lifeTime) + datetime.datetime.utcnow()
329 self.expiration = lifeTime
332 # get the lifetime of the credential (in datetime format)
334 def get_lifetime(self):
335 if not self.expiration:
337 return self.expiration
343 # @param privs either a comma-separated list of privileges of a Rights object
345 def set_privileges(self, privs):
346 if isinstance(privs, str):
347 self.privileges = Rights(string = privs)
349 self.privileges = privs
353 # return the privileges as a Rights object
355 def get_privileges(self):
356 if not self.privileges:
358 return self.privileges
361 # determine whether the credential allows a particular operation to be
364 # @param op_name string specifying name of operation ("lookup", "update", etc)
366 def can_perform(self, op_name):
367 rights = self.get_privileges()
372 return rights.can_perform(op_name)
376 # Encode the attributes of the credential into an XML string
377 # This should be done immediately before signing the credential.
379 # In general, a signed credential obtained externally should
380 # not be changed else the signature is no longer valid. So, once
381 # you have loaded an existing signed credential, do not call encode() or sign() on it.
384 # Create the XML document
386 signed_cred = doc.createElement("signed-credential")
387 doc.appendChild(signed_cred)
389 # Fill in the <credential> bit
390 cred = doc.createElement("credential")
391 cred.setAttribute("xml:id", self.get_refid())
392 signed_cred.appendChild(cred)
393 append_sub(doc, cred, "type", "privilege")
394 append_sub(doc, cred, "serial", "8")
395 append_sub(doc, cred, "owner_gid", self.gidCaller.save_to_string())
396 append_sub(doc, cred, "owner_urn", self.gidCaller.get_urn())
397 append_sub(doc, cred, "target_gid", self.gidObject.save_to_string())
398 append_sub(doc, cred, "target_urn", self.gidObject.get_urn())
399 append_sub(doc, cred, "uuid", "")
400 if not self.expiration:
401 self.set_lifetime(DEFAULT_CREDENTIAL_LIFETIME)
402 self.expiration = self.expiration.replace(microsecond=0)
403 append_sub(doc, cred, "expires", self.expiration.isoformat())
404 privileges = doc.createElement("privileges")
405 cred.appendChild(privileges)
408 rights = self.get_privileges()
409 for right in rights.rights:
410 priv = doc.createElement("privilege")
411 append_sub(doc, priv, "name", right.kind)
412 append_sub(doc, priv, "can_delegate", str(right.delegate).lower())
413 privileges.appendChild(priv)
415 # Add the parent credential if it exists
417 sdoc = parseString(self.parent.get_xml())
418 p_cred = doc.importNode(sdoc.getElementsByTagName("credential")[0], True)
419 p = doc.createElement("parent")
420 p.appendChild(p_cred)
424 # Create the <signatures> tag
425 signatures = doc.createElement("signatures")
426 signed_cred.appendChild(signatures)
428 # Add any parent signatures
430 for cur_cred in self.get_credential_list()[1:]:
431 sdoc = parseString(cur_cred.get_signature().get_xml())
432 ele = doc.importNode(sdoc.getElementsByTagName("Signature")[0], True)
433 signatures.appendChild(ele)
435 # Get the finished product
436 self.xml = doc.toxml()
439 def save_to_random_tmp_file(self):
440 fp, filename = mkstemp(suffix='cred', text=True)
441 fp = os.fdopen(fp, "w")
442 self.save_to_file(filename, save_parents=True, filep=fp)
445 def save_to_file(self, filename, save_parents=True, filep=None):
451 f = open(filename, "w")
455 def save_to_string(self, save_parents=True):
465 def set_refid(self, rid):
469 # Figure out what refids exist, and update this credential's id
470 # so that it doesn't clobber the others. Returns the refids of
473 def updateRefID(self):
475 self.set_refid('ref0')
480 next_cred = self.parent
482 refs.append(next_cred.get_refid())
484 next_cred = next_cred.parent
489 # Find a unique refid for this credential
490 rid = self.get_refid()
493 rid = "ref%d" % (val + 1)
498 # Return the set of parent credential ref ids
507 # Sign the XML file created by encode()
510 # In general, a signed credential obtained externally should
511 # not be changed else the signature is no longer valid. So, once
512 # you have loaded an existing signed credential, do not call encode() or sign() on it.
515 if not self.issuer_privkey or not self.issuer_gid:
517 doc = parseString(self.get_xml())
518 sigs = doc.getElementsByTagName("signatures")[0]
520 # Create the signature template to be signed
521 signature = Signature()
522 signature.set_refid(self.get_refid())
523 sdoc = parseString(signature.get_xml())
524 sig_ele = doc.importNode(sdoc.getElementsByTagName("Signature")[0], True)
525 sigs.appendChild(sig_ele)
527 self.xml = doc.toxml()
530 # Split the issuer GID into multiple certificates if it's a chain
531 chain = GID(filename=self.issuer_gid)
534 gid_files.append(chain.save_to_random_tmp_file(False))
535 if chain.get_parent():
536 chain = chain.get_parent()
541 # Call out to xmlsec1 to sign it
542 ref = 'Sig_%s' % self.get_refid()
543 filename = self.save_to_random_tmp_file()
544 signed = os.popen('%s --sign --node-id "%s" --privkey-pem %s,%s %s' \
545 % (self.xmlsec_path, ref, self.issuer_privkey, ",".join(gid_files), filename)).read()
548 for gid_file in gid_files:
553 # This is no longer a legacy credential
562 # Retrieve the attributes of the credential from the XML.
563 # This is automatically called by the various get_* methods of
564 # this class and should not need to be called explicitly.
569 doc = parseString(self.xml)
571 signed_cred = doc.getElementsByTagName("signed-credential")
573 # Is this a signed-cred or just a cred?
574 if len(signed_cred) > 0:
575 cred = signed_cred[0].getElementsByTagName("credential")[0]
576 signatures = signed_cred[0].getElementsByTagName("signatures")
577 if len(signatures) > 0:
578 sigs = signatures[0].getElementsByTagName("Signature")
580 cred = doc.getElementsByTagName("credential")[0]
583 self.set_refid(cred.getAttribute("xml:id"))
584 self.set_lifetime(parse(getTextNode(cred, "expires")))
585 self.gidCaller = GID(string=getTextNode(cred, "owner_gid"))
586 self.gidObject = GID(string=getTextNode(cred, "target_gid"))
590 privs = cred.getElementsByTagName("privileges")[0]
592 for priv in privs.getElementsByTagName("privilege"):
593 kind = getTextNode(priv, "name")
594 deleg = str2bool(getTextNode(priv, "can_delegate"))
596 # Convert * into the default privileges for the credential's type
597 _ , type = urn_to_hrn(self.gidObject.get_urn())
598 rl = rlist.determine_rights(type, self.gidObject.get_urn())
602 rlist.add(Right(kind.strip(), deleg))
603 self.set_privileges(rlist)
607 parent = cred.getElementsByTagName("parent")
609 parent_doc = parent[0].getElementsByTagName("credential")[0]
610 parent_xml = parent_doc.toxml()
611 self.parent = Credential(string=parent_xml)
614 # Assign the signatures to the credentials
616 Sig = Signature(string=sig.toxml())
618 for cur_cred in self.get_credential_list():
619 if cur_cred.get_refid() == Sig.get_refid():
620 cur_cred.set_signature(Sig)
625 # trusted_certs: A list of trusted GID filenames (not GID objects!)
626 # Chaining is not supported within the GIDs by xmlsec1.
629 # . All of the signatures are valid and that the issuers trace back
630 # to trusted roots (performed by xmlsec1)
631 # . The XML matches the credential schema
632 # . That the issuer of the credential is the authority in the target's urn
633 # . In the case of a delegated credential, this must be true of the root
634 # . That all of the gids presented in the credential are valid
635 # . The credential is not expired
637 # -- For Delegates (credentials with parents)
638 # . The privileges must be a subset of the parent credentials
639 # . The privileges must have "can_delegate" set for each delegated privilege
640 # . The target gid must be the same between child and parents
641 # . The expiry time on the child must be no later than the parent
642 # . The signer of the child must be the owner of the parent
644 # -- Verify does *NOT*
645 # . ensure that an xmlrpc client's gid matches a credential gid, that
646 # must be done elsewhere
648 # @param trusted_certs: The certificates of trusted CA certificates
649 def verify(self, trusted_certs):
653 # trusted_cert_objects = [GID(filename=f) for f in trusted_certs]
654 trusted_cert_objects = []
655 ok_trusted_certs = []
656 for f in trusted_certs:
658 # Failures here include unreadable files
660 trusted_cert_objects.append(GID(filename=f))
661 ok_trusted_certs.append(f)
662 except Exception, exc:
663 sfa_logger().error("Failed to load trusted cert from %s: %r", f, exc)
664 trusted_certs = ok_trusted_certs
666 # Use legacy verification if this is a legacy credential
668 self.legacy.verify_chain(trusted_cert_objects)
669 if self.legacy.client_gid:
670 self.legacy.client_gid.verify_chain(trusted_cert_objects)
671 if self.legacy.object_gid:
672 self.legacy.object_gid.verify_chain(trusted_cert_objects)
675 # make sure it is not expired
676 if self.get_lifetime() < datetime.datetime.utcnow():
677 raise CredentialNotVerifiable("Credential expired at %s" % self.expiration.isoformat())
679 # Verify the signatures
680 filename = self.save_to_random_tmp_file()
681 cert_args = " ".join(['--trusted-pem %s' % x for x in trusted_certs])
683 # Verify the gids of this cred and of its parents
684 for cur_cred in self.get_credential_list():
685 cur_cred.get_gid_object().verify_chain(trusted_cert_objects)
686 cur_cred.get_gid_caller().verify_chain(trusted_cert_objects)
689 refs.append("Sig_%s" % self.get_refid())
691 parentRefs = self.updateRefID()
692 for ref in parentRefs:
693 refs.append("Sig_%s" % ref)
696 verified = os.popen('%s --verify --node-id "%s" %s %s 2>&1' \
697 % (self.xmlsec_path, ref, cert_args, filename)).read()
698 if not verified.strip().startswith("OK"):
699 raise CredentialNotVerifiable("xmlsec1 error verifying cert: " + verified)
702 # Verify the parents (delegation)
704 self.verify_parent(self.parent)
706 # Make sure the issuer is the target's authority
711 # Creates a list of the credential and its parents, with the root
712 # (original delegated credential) as the last item in the list
713 def get_credential_list(self):
717 list.append(cur_cred)
719 cur_cred = cur_cred.parent
725 # Make sure the credential's target gid was signed by (or is the same) the entity that signed
726 # the original credential or an authority over that namespace.
727 def verify_issuer(self):
728 root_cred = self.get_credential_list()[-1]
729 root_target_gid = root_cred.get_gid_object()
730 root_cred_signer = root_cred.get_signature().get_issuer_gid()
732 if root_target_gid.is_signed_by_cert(root_cred_signer):
733 # cred signer matches target signer, return success
736 root_target_gid_str = root_target_gid.save_to_string()
737 root_cred_signer_str = root_cred_signer.save_to_string()
738 if root_target_gid_str == root_cred_signer_str:
739 # cred signer is target, return success
742 # See if it the signer is an authority over the domain of the target
743 # Maybe should be (hrn, type) = urn_to_hrn(root_cred_signer.get_urn())
744 root_cred_signer_type = root_cred_signer.get_type()
745 if (root_cred_signer_type == 'authority'):
746 #sfa_logger().debug('Cred signer is an authority')
747 # signer is an authority, see if target is in authority's domain
748 hrn = root_cred_signer.get_hrn()
749 if root_target_gid.get_hrn().startswith(hrn):
752 # We've required that the credential be signed by an authority
753 # for that domain. Reasonable and probably correct.
754 # A looser model would also allow the signer to be an authority
755 # in my control framework - eg My CA or CH. Even if it is not
756 # the CH that issued these, eg, user credentials.
758 # Give up, credential does not pass issuer verification
760 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()))
764 # -- For Delegates (credentials with parents) verify that:
765 # . The privileges must be a subset of the parent credentials
766 # . The privileges must have "can_delegate" set for each delegated privilege
767 # . The target gid must be the same between child and parents
768 # . The expiry time on the child must be no later than the parent
769 # . The signer of the child must be the owner of the parent
770 def verify_parent(self, parent_cred):
771 # make sure the rights given to the child are a subset of the
772 # parents rights (and check delegate bits)
773 if not parent_cred.get_privileges().is_superset(self.get_privileges()):
774 raise ChildRightsNotSubsetOfParent(
775 self.parent.get_privileges().save_to_string() + " " +
776 self.get_privileges().save_to_string())
778 # make sure my target gid is the same as the parent's
779 if not parent_cred.get_gid_object().save_to_string() == \
780 self.get_gid_object().save_to_string():
781 raise CredentialNotVerifiable("Target gid not equal between parent and child")
783 # make sure my expiry time is <= my parent's
784 if not parent_cred.get_lifetime() >= self.get_lifetime():
785 raise CredentialNotVerifiable("Delegated credential expires after parent")
787 # make sure my signer is the parent's caller
788 if not parent_cred.get_gid_caller().save_to_string(False) == \
789 self.get_signature().get_issuer_gid().save_to_string(False):
790 raise CredentialNotVerifiable("Delegated credential not signed by parent caller")
793 if parent_cred.parent:
794 parent_cred.verify_parent(parent_cred.parent)
797 def delegate(self, delegee_gidfile, caller_keyfile, caller_gidfile):
799 Return a delegated copy of this credential, delegated to the
800 specified gid's user.
802 # get the gid of the object we are delegating
803 object_gid = self.get_gid_object()
804 object_hrn = object_gid.get_hrn()
806 # the hrn of the user who will be delegated to
807 delegee_gid = GID(filename=delegee_gidfile)
808 delegee_hrn = delegee_gid.get_hrn()
810 #user_key = Keypair(filename=keyfile)
811 #user_hrn = self.get_gid_caller().get_hrn()
812 subject_string = "%s delegated to %s" % (object_hrn, delegee_hrn)
813 dcred = Credential(subject=subject_string)
814 dcred.set_gid_caller(delegee_gid)
815 dcred.set_gid_object(object_gid)
816 dcred.set_parent(self)
817 dcred.set_lifetime(self.get_lifetime())
818 dcred.set_privileges(self.get_privileges())
819 dcred.get_privileges().delegate_all_privileges(True)
820 #dcred.set_issuer_keys(keyfile, delegee_gidfile)
821 dcred.set_issuer_keys(caller_keyfile, caller_gidfile)
827 # Dump the contents of a credential to stdout in human-readable format
829 # @param dump_parents If true, also dump the parent certificates
831 def dump(self, dump_parents=False):
832 print "CREDENTIAL", self.get_subject()
834 print " privs:", self.get_privileges().save_to_string()
837 gidCaller = self.get_gid_caller()
839 gidCaller.dump(8, dump_parents)
842 gidObject = self.get_gid_object()
844 gidObject.dump(8, dump_parents)
847 if self.parent and dump_parents:
849 self.parent.dump_parents()