X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=sfa%2Ftrust%2Fcredential.py;h=301fefe439a212b53f43fe1be7db97511525bba0;hb=3147e8e089dd44e40b852cc121483189807ffa9b;hp=90266bea87fcbe8e1f09d813b327ad39845c00c3;hpb=bd476e2109e29d1ed1adca949381853cfe619dac;p=sfa.git
diff --git a/sfa/trust/credential.py b/sfa/trust/credential.py
index 90266bea..301fefe4 100644
--- a/sfa/trust/credential.py
+++ b/sfa/trust/credential.py
@@ -1,45 +1,378 @@
+# ----------------------------------------------------------------------
+# Copyright (c) 2008 Board of Trustees, Princeton University
+#
+# Permission is hereby granted, free of charge, to any person obtaining
+# a copy of this software and/or hardware specification (the "Work") to
+# deal in the Work without restriction, including without limitation the
+# rights to use, copy, modify, merge, publish, distribute, sublicense,
+# and/or sell copies of the Work, and to permit persons to whom the Work
+# is furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be
+# included in all copies or substantial portions of the Work.
+#
+# THE WORK IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+# OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+# HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+# WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE WORK OR THE USE OR OTHER DEALINGS
+# IN THE WORK.
+# ----------------------------------------------------------------------
##
-# Implements Geni Credentials
+# Implements SFA Credentials
#
-# Credentials are layered on top of certificates, and are essentially a
-# certificate that stores a tuple of parameters.
+# Credentials are signed XML files that assign a subject gid
+# privileges to an object gid
+##
+
+from __future__ import print_function
+
+import os
+import os.path
+import subprocess
+import datetime
+from tempfile import mkstemp
+from xml.dom.minidom import Document, parseString
+
+from sfa.util.py23 import PY3, StringType, StringIO
+
+from xml.parsers.expat import ExpatError
+
+from sfa.util.faults import (CredentialNotVerifiable,
+ ChildRightsNotSubsetOfParent)
+from sfa.util.sfalogging import logger
+from sfa.util.sfatime import utcparse, SFATIME_FORMAT
+from sfa.trust.rights import Right, Rights, determine_rights
+from sfa.trust.gid import GID
+from sfa.util.xrn import urn_to_hrn, hrn_authfor_hrn
+
+HAVELXML = False
+try:
+ from lxml import etree
+ HAVELXML = True
+except:
+ pass
+
+
+# 31 days, in seconds
+DEFAULT_CREDENTIAL_LIFETIME = 86400 * 31
+
+
+# TODO:
+# . make privs match between PG and PL
+# . Need to add support for other types of credentials, e.g. tickets
+# . add namespaces to signed-credential element?
+
+signature_format = \
+ '''
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+'''
+
+##
+# Convert a string into a bool
+# used to convert an xsd:boolean to a Python boolean
+
+
+def str2bool(str):
+ if str.lower() in ('true', '1'):
+ return True
+ return False
+
+
+##
+# Utility function to get the text of an XML element
+
+def getTextNode(element, subele):
+ sub = element.getElementsByTagName(subele)[0]
+ if len(sub.childNodes) > 0:
+ return sub.childNodes[0].nodeValue
+ else:
+ return None
+
+##
+# Utility function to set the text of an XML element
+# It creates the element, adds the text to it,
+# and then appends it to the parent.
+
+
+def append_sub(doc, parent, element, text):
+ ele = doc.createElement(element)
+ ele.appendChild(doc.createTextNode(text))
+ parent.appendChild(ele)
+
##
+# Signature contains information about an xmlsec1 signature
+# for a signed-credential
+#
-### $Id$
-### $URL$
-import xmlrpclib
+class Signature(object):
-from sfa.trust.certificate import Certificate
-from sfa.trust.rights import *
-from sfa.trust.gid import *
-from sfa.util.faults import *
+ def __init__(self, string=None):
+ self.refid = None
+ self.issuer_gid = None
+ self.xml = None
+ if string:
+ self.xml = string
+ self.decode()
+
+ def get_refid(self):
+ if not self.refid:
+ self.decode()
+ return self.refid
+
+ def get_xml(self):
+ if not self.xml:
+ self.encode()
+ return self.xml
+
+ def set_refid(self, id):
+ self.refid = id
+
+ def get_issuer_gid(self):
+ if not self.gid:
+ self.decode()
+ return self.gid
+
+ def set_issuer_gid(self, gid):
+ self.gid = gid
+
+ def decode(self):
+ # Helper function to pull characters off the front of a string if
+ # present
+ def remove_prefix(text, prefix):
+ if text and prefix and text.startswith(prefix):
+ return text[len(prefix):]
+ return text
+
+ try:
+ doc = parseString(self.xml)
+ except ExpatError as e:
+ logger.log_exc("Failed to parse credential, {}".format(self.xml))
+ raise
+ sig = doc.getElementsByTagName("Signature")[0]
+ # This code until the end of function rewritten by Aaron Helsinger
+ ref_id = remove_prefix(sig.getAttribute("xml:id").strip(), "Sig_")
+ # The xml:id tag is optional, and could be in a
+ # Reference xml:id or Reference UID sub element instead
+ if not ref_id or ref_id == '':
+ reference = sig.getElementsByTagName('Reference')[0]
+ ref_id = remove_prefix(
+ reference.getAttribute('xml:id').strip(), "Sig_")
+ if not ref_id or ref_id == '':
+ ref_id = remove_prefix(
+ reference.getAttribute('URI').strip(), "#")
+ self.set_refid(ref_id)
+ keyinfos = sig.getElementsByTagName("X509Data")
+ gids = None
+ for keyinfo in keyinfos:
+ certs = keyinfo.getElementsByTagName("X509Certificate")
+ for cert in certs:
+ if len(cert.childNodes) > 0:
+ szgid = cert.childNodes[0].nodeValue
+ szgid = szgid.strip()
+ szgid = "-----BEGIN CERTIFICATE-----\n"\
+ "{}\n-----END CERTIFICATE-----".format(
+ szgid)
+ if gids is None:
+ gids = szgid
+ else:
+ gids += "\n" + szgid
+ if gids is None:
+ raise CredentialNotVerifiable(
+ "Malformed XML: No certificate found in signature")
+ self.set_issuer_gid(GID(string=gids))
+
+ def encode(self):
+ self.xml = signature_format.format(refid=self.get_refid())
##
-# Credential is a tuple:
-# (GIDCaller, GIDObject, LifeTime, Privileges, Delegate)
+# A credential provides a caller gid with privileges to an object gid.
+# A signed credential is signed by the object's authority.
+#
+# Credentials are encoded in one of two ways. The legacy style (now
+# unsupported) places it in the subjectAltName of an X509 certificate.
+# The new credentials are placed in signed XML.
#
-# These fields are encoded using xmlrpc into the subjectAltName field of the
-# x509 certificate. Note: Call encode() once the fields have been filled in
-# to perform this encoding.
+# WARNING:
+# In general, a signed credential obtained externally should
+# not be changed else the signature is no longer valid. So, once
+# you have loaded an existing signed credential, do not call encode() or
+# sign() on it.
+
+
+def filter_creds_by_caller(creds, caller_hrn_list):
+ """
+ Returns a list of creds who's gid caller matches the
+ specified caller hrn
+ """
+ if not isinstance(creds, list):
+ creds = [creds]
+ if not isinstance(caller_hrn_list, list):
+ caller_hrn_list = [caller_hrn_list]
+ caller_creds = []
+ for cred in creds:
+ try:
+ tmp_cred = Credential(string=cred)
+ if tmp_cred.type != Credential.SFA_CREDENTIAL_TYPE:
+ continue
+ if tmp_cred.get_gid_caller().get_hrn() in caller_hrn_list:
+ caller_creds.append(cred)
+ except:
+ pass
+ return caller_creds
+
-class Credential(Certificate):
- gidCaller = None
- gidObject = None
- lifeTime = None
- privileges = None
- delegate = False
+class Credential(object):
+
+ SFA_CREDENTIAL_TYPE = "geni_sfa"
##
# Create a Credential object
#
# @param create If true, create a blank x509 certificate
- # @param subject If subject!=None, create an x509 cert with the subject name
+ # @param subject If subject!=None,
+ # create an x509 cert with the subject name
# @param string If string!=None, load the credential from the string
# @param filename If filename!=None, load the credential from the file
+ # FIXME: create and subject are ignored!
+ def __init__(self, create=False, subject=None, string=None,
+ filename=None, cred=None):
+ self.gidCaller = None
+ self.gidObject = None
+ self.expiration = None
+ self.privileges = None
+ self.issuer_privkey = None
+ self.issuer_gid = None
+ self.issuer_pubkey = None
+ self.parent = None
+ self.signature = None
+ self.xml = None
+ self.refid = None
+ self.type = Credential.SFA_CREDENTIAL_TYPE
+ self.version = None
+
+ if cred:
+ if isinstance(cred, StringType):
+ string = cred
+ self.type = Credential.SFA_CREDENTIAL_TYPE
+ self.version = '3'
+ elif isinstance(cred, dict):
+ string = cred['geni_value']
+ self.type = cred['geni_type']
+ self.version = cred['geni_version']
+
+ if string or filename:
+ if string:
+ str = string
+ elif filename:
+ with open(filename) as infile:
+ str = infile.read()
+
+ # if this is a legacy credential, write error and bail out
+ if isinstance(str, StringType) and str.strip().startswith("-----"):
+ logger.error(
+ "Legacy credentials not supported any more "
+ "- giving up with {}..."
+ .format(str[:10]))
+ return
+ else:
+ self.xml = str
+ self.decode()
+ # not strictly necessary but won't hurt either
+ self.get_xmlsec1_path()
+
+ @staticmethod
+ def get_xmlsec1_path():
+ if not getattr(Credential, 'xmlsec1_path', None):
+ # Find a xmlsec1 binary path
+ Credential.xmlsec1_path = ''
+ paths = ['/usr/bin', '/usr/local/bin',
+ '/bin', '/opt/bin', '/opt/local/bin']
+ try:
+ paths += os.getenv('PATH').split(':')
+ except:
+ pass
+ for path in paths:
+ xmlsec1 = os.path.join(path, 'xmlsec1')
+ if os.path.isfile(xmlsec1):
+ Credential.xmlsec1_path = xmlsec1
+ break
+ if not Credential.xmlsec1_path:
+ logger.error(
+ "Could not locate required binary 'xmlsec1' -"
+ "SFA will be unable to sign stuff !!")
+ return Credential.xmlsec1_path
+
+ def get_subject(self):
+ if not self.gidObject:
+ self.decode()
+ return self.gidObject.get_subject()
- def __init__(self, create=False, subject=None, string=None, filename=None):
- Certificate.__init__(self, create, subject, string, filename)
+ def pretty_subject(self):
+ subject = ""
+ if not self.gidObject:
+ self.decode()
+ if self.gidObject:
+ subject = self.gidObject.pretty_cert()
+ return subject
+
+ # sounds like this should be __repr__ instead ??
+ def pretty_cred(self):
+ if not self.gidObject:
+ self.decode()
+ obj = self.gidObject.pretty_cert()
+ caller = self.gidCaller.pretty_cert()
+ exp = self.get_expiration()
+ # Summarize the rights too? The issuer?
+ return "[Cred. for {caller} rights on {obj} until {exp} ]"\
+ .format(**locals())
+
+ def get_signature(self):
+ if not self.signature:
+ self.decode()
+ return self.signature
+
+ def set_signature(self, sig):
+ self.signature = sig
+
+ ##
+ # Need the issuer's private key and name
+ # @param key Keypair object containing the private key of the issuer
+ # @param gid GID of the issuing authority
+
+ def set_issuer_keys(self, privkey, gid):
+ self.issuer_privkey = privkey
+ self.issuer_gid = gid
+
+ ##
+ # Set this credential's parent
+ def set_parent(self, cred):
+ self.parent = cred
+ self.updateRefID()
##
# set the GID of the caller
@@ -48,6 +381,8 @@ class Credential(Certificate):
def set_gid_caller(self, gid):
self.gidCaller = gid
+ # gid origin caller is the caller's gid by default
+ self.gidOriginCaller = gid
##
# get the GID of the object
@@ -73,51 +408,43 @@ class Credential(Certificate):
self.decode()
return self.gidObject
- ##
- # set the lifetime of this credential
#
- # @param lifetime lifetime of credential
-
- def set_lifetime(self, lifeTime):
- self.lifeTime = lifeTime
-
- ##
- # get the lifetime of the credential
-
- def get_lifetime(self):
- if not self.lifeTime:
- self.decode()
- return self.lifeTime
-
- ##
- # set the delegate bit
+ # Expiration: an absolute UTC time of expiration (as either an int
+ # or string or datetime)
#
- # @param delegate boolean (True or False)
-
- def set_delegate(self, delegate):
- self.delegate = delegate
+ def set_expiration(self, expiration):
+ expiration_datetime = utcparse(expiration)
+ if expiration_datetime is not None:
+ self.expiration = expiration_datetime
+ else:
+ logger.error(
+ "unexpected input {} in Credential.set_expiration"
+ .format(expiration))
##
- # get the delegate bit
+ # get the lifetime of the credential (always in datetime format)
- def get_delegate(self):
- if not self.delegate:
+ def get_expiration(self):
+ if not self.expiration:
self.decode()
- return self.delegate
+ # at this point self.expiration is normalized as a datetime - DON'T
+ # call utcparse again
+ return self.expiration
##
# set the privileges
#
- # @param privs either a comma-separated list of privileges of a RightList object
+ # @param privs either a comma-separated list of privileges of a
+ # Rights object
def set_privileges(self, privs):
if isinstance(privs, str):
- self.privileges = RightList(string = privs)
+ self.privileges = Rights(string=privs)
else:
self.privileges = privs
##
- # return the privileges as a RightList object
+ # return the privileges as a Rights object
def get_privileges(self):
if not self.privileges:
@@ -128,116 +455,831 @@ class Credential(Certificate):
# determine whether the credential allows a particular operation to be
# performed
#
- # @param op_name string specifying name of operation ("lookup", "update", etc)
+ # @param op_name string specifying name of operation
+ # ("lookup", "update", etc)
def can_perform(self, op_name):
rights = self.get_privileges()
+
if not rights:
return False
+
return rights.can_perform(op_name)
##
- # Encode the attributes of the credential into a string and store that
- # string in the alt-subject-name field of the X509 object. This should be
- # done immediately before signing the credential.
+ # Encode the attributes of the credential into an XML string
+ # This should be done immediately before signing the credential.
+ # WARNING:
+ # In general, a signed credential obtained externally should
+ # not be changed else the signature is no longer valid. So, once
+ # you have loaded an existing signed credential, do not call encode() or
+ # sign() on it.
def encode(self):
- dict = {"gidCaller": None,
- "gidObject": None,
- "lifeTime": self.lifeTime,
- "privileges": None,
- "delegate": self.delegate}
- if self.gidCaller:
- dict["gidCaller"] = self.gidCaller.save_to_string(save_parents=True)
- if self.gidObject:
- dict["gidObject"] = self.gidObject.save_to_string(save_parents=True)
+ # Create the XML document
+ doc = Document()
+ signed_cred = doc.createElement("signed-credential")
+
+ # Declare namespaces
+ # Note that credential/policy.xsd are really the PG schemas
+ # in a PL namespace.
+ # Note that delegation of credentials between the 2 only really works
+ # cause those schemas are identical.
+ # Also note these PG schemas talk about PG tickets and CM policies.
+ signed_cred.setAttribute(
+ "xmlns:xsi", "http://www.w3.org/2001/XMLSchema-instance")
+ # FIXME: See v2 schema at
+ # www.geni.net/resources/credential/2/credential.xsd
+ signed_cred.setAttribute(
+ "xsi:noNamespaceSchemaLocation",
+ "http://www.planet-lab.org/resources/sfa/credential.xsd")
+ 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")
+
+ # PG says for those last 2:
+ # signed_cred.setAttribute("xsi:noNamespaceSchemaLocation",
+ # "http://www.protogeni.net/resources/credential/credential.xsd")
+ # 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")
+
+ doc.appendChild(signed_cred)
+
+ # Fill in the bit
+ cred = doc.createElement("credential")
+ cred.setAttribute("xml:id", self.get_refid())
+ signed_cred.appendChild(cred)
+ append_sub(doc, cred, "type", "privilege")
+ append_sub(doc, cred, "serial", "8")
+ append_sub(doc, cred, "owner_gid", self.gidCaller.save_to_string())
+ append_sub(doc, cred, "owner_urn", self.gidCaller.get_urn())
+ append_sub(doc, cred, "target_gid", self.gidObject.save_to_string())
+ append_sub(doc, cred, "target_urn", self.gidObject.get_urn())
+ append_sub(doc, cred, "uuid", "")
+ if not self.expiration:
+ logger.debug("Creating credential valid for {} s".format(
+ DEFAULT_CREDENTIAL_LIFETIME))
+ self.set_expiration(datetime.datetime.utcnow(
+ ) + datetime.timedelta(seconds=DEFAULT_CREDENTIAL_LIFETIME))
+ self.expiration = self.expiration.replace(microsecond=0)
+ if self.expiration.tzinfo is not None \
+ and self.expiration.tzinfo.utcoffset(self.expiration) is not None:
+ # TZ aware. Make sure it is UTC - by Aaron Helsinger
+ self.expiration = self.expiration.astimezone(tz.tzutc())
+ append_sub(doc, cred, "expires",
+ self.expiration.strftime(SFATIME_FORMAT))
+ privileges = doc.createElement("privileges")
+ cred.appendChild(privileges)
+
if self.privileges:
- dict["privileges"] = self.privileges.save_to_string()
- str = xmlrpclib.dumps((dict,), allow_none=True)
- self.set_data(str)
+ rights = self.get_privileges()
+ for right in rights.rights:
+ priv = doc.createElement("privilege")
+ append_sub(doc, priv, "name", right.kind)
+ append_sub(doc, priv, "can_delegate",
+ str(right.delegate).lower())
+ privileges.appendChild(priv)
+
+ # Add the parent credential if it exists
+ if self.parent:
+ sdoc = parseString(self.parent.get_xml())
+ # If the root node is a signed-credential (it should be), then
+ # get all its attributes and attach those to our signed_cred
+ # node.
+ # Specifically, PG and PL add attributes for namespaces
+ # (which is reasonable),
+ # and we need to include those again here or else their signature
+ # no longer matches on the credential.
+ # We expect three of these, but here we copy them all:
+ # signed_cred.setAttribute("xmlns:xsi",
+ # "http://www.w3.org/2001/XMLSchema-instance")
+ # and from PG (PL is equivalent, as shown above):
+ # signed_cred.setAttribute("xsi:noNamespaceSchemaLocation",
+ # "http://www.protogeni.net/resources/credential/credential.xsd")
+ # 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")
+
+ # HOWEVER!
+ # PL now also declares these, with different URLs, so
+ # the code notices those attributes already existed with
+ # different values, and complains.
+ # This happens regularly on delegation now that PG and
+ # PL both declare the namespace with different URLs.
+ # If the content ever differs this is a problem,
+ # but for now it works - different URLs (values in the attributes)
+ # but the same actual schema, so using the PG schema
+ # on delegated-to-PL credentials works fine.
+
+ # Note: you could also not copy attributes
+ # which already exist. It appears that both PG and PL
+ # will actually validate a slicecred with a parent
+ # signed using PG namespaces and a child signed with PL
+ # namespaces over the whole thing. But I don't know
+ # if that is a bug in xmlsec1, an accident since
+ # the contents of the schemas are the same,
+ # or something else, but it seems odd. And this works.
+ parentRoot = sdoc.documentElement
+ if parentRoot.tagName == "signed-credential" and \
+ parentRoot.hasAttributes():
+ for attrIx in range(0, parentRoot.attributes.length):
+ attr = parentRoot.attributes.item(attrIx)
+ # returns the old attribute of same name that was
+ # on the credential
+ # Below throws InUse exception if we forgot to clone the
+ # attribute first
+ oldAttr = signed_cred.setAttributeNode(
+ attr.cloneNode(True))
+ if oldAttr and oldAttr.value != attr.value:
+ msg = "Delegating cred from owner {} to {} over {}:\n"
+ "- Replaced attribute {} value '{}' with '{}'"\
+ .format(self.parent.gidCaller.get_urn(),
+ self.gidCaller.get_urn(),
+ self.gidObject.get_urn(),
+ oldAttr.name, oldAttr.value, attr.value)
+ logger.warning(msg)
+ # raise CredentialNotVerifiable(
+ # "Can't encode new valid delegated credential: {}"
+ # .format(msg))
+
+ p_cred = doc.importNode(
+ sdoc.getElementsByTagName("credential")[0], True)
+ p = doc.createElement("parent")
+ p.appendChild(p_cred)
+ cred.appendChild(p)
+ # done handling parent credential
+
+ # Create the tag
+ signatures = doc.createElement("signatures")
+ signed_cred.appendChild(signatures)
+
+ # Add any parent signatures
+ if self.parent:
+ for cur_cred in self.get_credential_list()[1:]:
+ sdoc = parseString(cur_cred.get_signature().get_xml())
+ ele = doc.importNode(
+ sdoc.getElementsByTagName("Signature")[0], True)
+ signatures.appendChild(ele)
+
+ # Get the finished product
+ self.xml = doc.toxml("utf-8")
+
+ def save_to_random_tmp_file(self):
+ fp, filename = mkstemp(suffix='cred', text=True)
+ fp = os.fdopen(fp, "w")
+ self.save_to_file(filename, save_parents=True, filep=fp)
+ return filename
+
+ def save_to_file(self, filename, save_parents=True, filep=None):
+ if not self.xml:
+ self.encode()
+ if filep:
+ f = filep
+ else:
+ f = open(filename, "w")
+ if PY3 and isinstance(self.xml, bytes):
+ self.xml = self.xml.decode()
+ f.write(self.xml)
+ f.close()
+
+ def save_to_string(self, save_parents=True):
+ if not self.xml:
+ self.encode()
+ if PY3 and isinstance(self.xml, bytes):
+ self.xml = self.xml.decode()
+ return self.xml
+
+ def get_refid(self):
+ if not self.refid:
+ self.refid = 'ref0'
+ return self.refid
+
+ def set_refid(self, rid):
+ self.refid = rid
##
- # Retrieve the attributes of the credential from the alt-subject-name field
- # of the X509 certificate. This is automatically done by the various
- # get_* methods of this class and should not need to be called explicitly.
+ # Figure out what refids exist, and update this credential's id
+ # so that it doesn't clobber the others. Returns the refids of
+ # the parents.
+
+ def updateRefID(self):
+ if not self.parent:
+ self.set_refid('ref0')
+ return []
+
+ refs = []
+
+ next_cred = self.parent
+ while next_cred:
+ refs.append(next_cred.get_refid())
+ if next_cred.parent:
+ next_cred = next_cred.parent
+ else:
+ next_cred = None
+
+ # Find a unique refid for this credential
+ rid = self.get_refid()
+ while rid in refs:
+ val = int(rid[3:])
+ rid = "ref{}".format(val + 1)
+
+ # Set the new refid
+ self.set_refid(rid)
+
+ # Return the set of parent credential ref ids
+ return refs
+
+ def get_xml(self):
+ if not self.xml:
+ self.encode()
+ return self.xml
+
+ ##
+ # Sign the XML file created by encode()
+ #
+ # WARNING:
+ # In general, a signed credential obtained externally should
+ # not be changed else the signature is no longer valid. So, once
+ # you have loaded an existing signed credential, do not call encode() or
+ # sign() on it.
+
+ def sign(self):
+ if not self.issuer_privkey:
+ logger.warning("Cannot sign credential (no private key)")
+ return
+ if not self.issuer_gid:
+ logger.warning("Cannot sign credential (no issuer gid)")
+ return
+ doc = parseString(self.get_xml())
+ sigs = doc.getElementsByTagName("signatures")[0]
+
+ # Create the signature template to be signed
+ signature = Signature()
+ signature.set_refid(self.get_refid())
+ sdoc = parseString(signature.get_xml())
+ sig_ele = doc.importNode(
+ sdoc.getElementsByTagName("Signature")[0], True)
+ sigs.appendChild(sig_ele)
+
+ self.xml = doc.toxml("utf-8")
+
+ # Split the issuer GID into multiple certificates if it's a chain
+ chain = GID(filename=self.issuer_gid)
+ gid_files = []
+ while chain:
+ gid_files.append(chain.save_to_random_tmp_file(False))
+ if chain.get_parent():
+ chain = chain.get_parent()
+ else:
+ chain = None
+
+ # Call out to xmlsec1 to sign it
+ ref = 'Sig_{}'.format(self.get_refid())
+ filename = self.save_to_random_tmp_file()
+ xmlsec1 = self.get_xmlsec1_path()
+ if not xmlsec1:
+ raise Exception("Could not locate required 'xmlsec1' program")
+ command = '{} --sign --node-id "{}" --privkey-pem {},{} {}' \
+ .format(xmlsec1, ref, self.issuer_privkey,
+ ",".join(gid_files), filename)
+ signed = os.popen(command).read()
+ os.remove(filename)
+
+ for gid_file in gid_files:
+ os.remove(gid_file)
+
+ self.xml = signed
+
+ # Update signatures
+ self.decode()
+
+ ##
+ # Retrieve the attributes of the credential from the XML.
+ # This is automatically called by the various get_* methods of
+ # this class and should not need to be called explicitly.
def decode(self):
- data = self.get_data()
- if data:
- dict = xmlrpclib.loads(self.get_data())[0][0]
- else:
- dict = {}
+ if not self.xml:
+ return
- self.lifeTime = dict.get("lifeTime", None)
- self.delegate = dict.get("delegate", None)
+ doc = None
+ try:
+ doc = parseString(self.xml)
+ except ExpatError as e:
+ raise CredentialNotVerifiable("Malformed credential")
+ doc = parseString(self.xml)
+ sigs = []
+ signed_cred = doc.getElementsByTagName("signed-credential")
- privStr = dict.get("privileges", None)
- if privStr:
- self.privileges = RightList(string = privStr)
+ # Is this a signed-cred or just a cred?
+ if len(signed_cred) > 0:
+ creds = signed_cred[0].getElementsByTagName("credential")
+ signatures = signed_cred[0].getElementsByTagName("signatures")
+ if len(signatures) > 0:
+ sigs = signatures[0].getElementsByTagName("Signature")
else:
- self.privileges = None
+ creds = doc.getElementsByTagName("credential")
- gidCallerStr = dict.get("gidCaller", None)
- if gidCallerStr:
- self.gidCaller = GID(string=gidCallerStr)
- else:
- self.gidCaller = None
+ if creds is None or len(creds) == 0:
+ # malformed cred file
+ raise CredentialNotVerifiable(
+ "Malformed XML: No credential tag found")
- gidObjectStr = dict.get("gidObject", None)
- if gidObjectStr:
- self.gidObject = GID(string=gidObjectStr)
- else:
- self.gidObject = None
+ # Just take the first cred if there are more than one
+ cred = creds[0]
+
+ self.set_refid(cred.getAttribute("xml:id"))
+ self.set_expiration(utcparse(getTextNode(cred, "expires")))
+ self.gidCaller = GID(string=getTextNode(cred, "owner_gid"))
+ self.gidObject = GID(string=getTextNode(cred, "target_gid"))
+
+ # This code until the end of function rewritten by Aaron Helsinger
+ # Process privileges
+ rlist = Rights()
+ priv_nodes = cred.getElementsByTagName("privileges")
+ if len(priv_nodes) > 0:
+ privs = priv_nodes[0]
+ for priv in privs.getElementsByTagName("privilege"):
+ kind = getTextNode(priv, "name")
+ deleg = str2bool(getTextNode(priv, "can_delegate"))
+ if kind == '*':
+ # Convert * into the default privileges
+ # for the credential's type
+ # Each inherits the delegatability from the * above
+ _, type = urn_to_hrn(self.gidObject.get_urn())
+ rl = determine_rights(type, self.gidObject.get_urn())
+ for r in rl.rights:
+ r.delegate = deleg
+ rlist.add(r)
+ else:
+ rlist.add(Right(kind.strip(), deleg))
+ self.set_privileges(rlist)
+
+ # Is there a parent?
+ parent = cred.getElementsByTagName("parent")
+ if len(parent) > 0:
+ parent_doc = parent[0].getElementsByTagName("credential")[0]
+ parent_xml = parent_doc.toxml("utf-8")
+ if parent_xml is None or parent_xml.strip() == "":
+ raise CredentialNotVerifiable(
+ "Malformed XML: Had parent tag but it is empty")
+ self.parent = Credential(string=parent_xml)
+ self.updateRefID()
+
+ # Assign the signatures to the credentials
+ for sig in sigs:
+ Sig = Signature(string=sig.toxml("utf-8"))
+
+ for cur_cred in self.get_credential_list():
+ if cur_cred.get_refid() == Sig.get_refid():
+ cur_cred.set_signature(Sig)
##
- # Verify that a chain of credentials is valid (see cert.py:verify). In
- # addition to the checks for ordinary certificates, verification also
- # ensures that the delegate bit was set by each parent in the chain. If
- # a delegate bit was not set, then an exception is thrown.
+ # Verify
+ # trusted_certs: A list of trusted GID filenames (not GID objects!)
+ # Chaining is not supported within the GIDs by xmlsec1.
+ #
+ # trusted_certs_required: Should usually be true. Set False means an
+ # empty list of trusted_certs would still let this method pass.
+ # It just skips xmlsec1 verification et al.
+ # Only used by some utils
+ #
+ # Verify that:
+ # . All of the signatures are valid and that the issuers trace back
+ # to trusted roots (performed by xmlsec1)
+ # . The XML matches the credential schema
+ # . That the issuer of the credential is the authority in the target's urn
+ # . In the case of a delegated credential, this must be true of the root
+ # . That all of the gids presented in the credential are valid
+ # . Including verifying GID chains, and includ the issuer
+ # . The credential is not expired
#
- # Each credential must be a subset of the rights of the parent.
+ # -- For Delegates (credentials with parents)
+ # . The privileges must be a subset of the parent credentials
+ # . The privileges must have "can_delegate"
+ # set for each delegated privilege
+ # . The target gid must be the same between child and parents
+ # . The expiry time on the child must be no later than the parent
+ # . The signer of the child must be the owner of the parent
+ #
+ # -- Verify does *NOT*
+ # . ensure that an xmlrpc client's gid matches a credential gid, that
+ # must be done elsewhere
+ #
+ # @param trusted_certs: The certificates of trusted CA certificates
+ def verify(self, trusted_certs=None, schema=None,
+ trusted_certs_required=True):
+ if not self.xml:
+ self.decode()
+
+ # validate against RelaxNG schema
+ if HAVELXML:
+ if schema and os.path.exists(schema):
+ tree = etree.parse(StringIO(self.xml))
+ schema_doc = etree.parse(schema)
+ xmlschema = etree.XMLSchema(schema_doc)
+ if not xmlschema.validate(tree):
+ error = xmlschema.error_log.last_error
+ message = "{}: {} (line {})"\
+ .format(self.pretty_cred(),
+ error.message, error.line)
+ raise CredentialNotVerifiable(message)
+
+ if trusted_certs_required and trusted_certs is None:
+ trusted_certs = []
- def verify_chain(self, trusted_certs = None):
- # do the normal certificate verification stuff
- Certificate.verify_chain(self, trusted_certs)
+# trusted_cert_objects = [GID(filename=f) for f in trusted_certs]
+ trusted_cert_objects = []
+ ok_trusted_certs = []
+ # If caller explicitly passed in None, that means
+ # skip cert chain validation. Strange and not typical
+ if trusted_certs is not None:
+ for f in trusted_certs:
+ try:
+ # Failures here include unreadable files
+ # or non PEM files
+ trusted_cert_objects.append(GID(filename=f))
+ ok_trusted_certs.append(f)
+ except Exception as exc:
+ logger.exception(
+ "Failed to load trusted cert from {}".format(f))
+ trusted_certs = ok_trusted_certs
+ # make sure it is not expired
+ if self.get_expiration() < datetime.datetime.utcnow():
+ raise CredentialNotVerifiable(
+ "Credential {} expired at {}"
+ .format(self.pretty_cred(),
+ self.expiration.strftime(SFATIME_FORMAT)))
+
+ # Verify the signatures
+ filename = self.save_to_random_tmp_file()
+
+ # If caller explicitly passed in None that means
+ # skip cert chain validation. Strange and not typical
+ if trusted_certs is not None:
+ # Verify the caller and object gids of this cred and of its parents
+ for cur_cred in self.get_credential_list():
+ # check both the caller and the subject
+ for gid in (cur_cred.get_gid_object(),
+ cur_cred.get_gid_caller()):
+ logger.debug("Credential.verify: verifying chain {}"
+ .format(gid.pretty_cert()))
+ logger.debug("Credential.verify: against trusted {}"
+ .format(" ".join(trusted_certs)))
+ gid.verify_chain(trusted_cert_objects)
+
+ refs = []
+ refs.append("Sig_{}".format(self.get_refid()))
+
+ parentRefs = self.updateRefID()
+ for ref in parentRefs:
+ refs.append("Sig_{}".format(ref))
+
+ for ref in refs:
+ # If caller explicitly passed in None that means
+ # skip xmlsec1 validation. Strange and not typical
+ if trusted_certs is None:
+ break
+
+ # Thierry - jan 2015
+ # up to fedora20 we used os.popen and checked
+ # that the output begins with OK; turns out, with fedora21,
+ # there is extra input before this 'OK' thing
+ # looks like we're better off just using the exit code
+ # that's what it is made for
+ # cert_args = " ".join(['--trusted-pem {}'.format(x) for x in trusted_certs])
+ # command = '{} --verify --node-id "{}" {} {} 2>&1'.\
+ # format(self.xmlsec_path, ref, cert_args, filename)
+ xmlsec1 = self.get_xmlsec1_path()
+ if not xmlsec1:
+ raise Exception("Could not locate required 'xmlsec1' program")
+ command = [xmlsec1, '--verify', '--node-id', ref]
+ for trusted in trusted_certs:
+ command += ["--trusted-pem", trusted]
+ command += [filename]
+ logger.debug("Running " + " ".join(command))
+ try:
+ verified = subprocess.check_output(
+ command, stderr=subprocess.STDOUT)
+ logger.debug("xmlsec command returned {}".format(verified))
+ if "OK\n" not in verified:
+ logger.warning(
+ "WARNING: xmlsec1 seemed to return fine but without a OK in its output")
+ except subprocess.CalledProcessError as e:
+ verified = e.output
+ # xmlsec errors have a msg= which is the interesting bit.
+ mstart = verified.find("msg=")
+ msg = ""
+ if mstart > -1 and len(verified) > 4:
+ mstart = mstart + 4
+ mend = verified.find('\\', mstart)
+ msg = verified[mstart:mend]
+ logger.warning(
+ "Credential.verify - failed - xmlsec1 returned {}"
+ .format(verified.strip()))
+ raise CredentialNotVerifiable(
+ "xmlsec1 error verifying cred {} using Signature ID {}: {}"
+ .format(self.pretty_cred(), ref, msg))
+ os.remove(filename)
+
+ # Verify the parents (delegation)
if self.parent:
- # make sure the parent delegated rights to the child
- if not self.parent.get_delegate():
- raise MissingDelegateBit(self.parent.get_subject())
+ self.verify_parent(self.parent)
- # make sure the rights given to the child are a subset of the
- # parents rights
- if not self.parent.get_privileges().is_superset(self.get_privileges()):
- raise ChildRightsNotSubsetOfParent(self.get_subject()
- + " " + self.parent.get_privileges().save_to_string()
- + " " + self.get_privileges().save_to_string())
+ # Make sure the issuer is the target's authority, and is
+ # itself a valid GID
+ self.verify_issuer(trusted_cert_objects)
+ return True
- return
+ ##
+ # Creates a list of the credential and its parents, with the root
+ # (original delegated credential) as the last item in the list
+ def get_credential_list(self):
+ cur_cred = self
+ list = []
+ while cur_cred:
+ list.append(cur_cred)
+ if cur_cred.parent:
+ cur_cred = cur_cred.parent
+ else:
+ cur_cred = None
+ return list
+
+ ##
+ # Make sure the credential's target gid (a) was signed by or (b)
+ # is the same as the entity that signed the original credential,
+ # or (c) is an authority over the target's namespace.
+ # Also ensure that the credential issuer / signer itself has a valid
+ # GID signature chain (signed by an authority with namespace rights).
+ def verify_issuer(self, trusted_gids):
+ root_cred = self.get_credential_list()[-1]
+ root_target_gid = root_cred.get_gid_object()
+ if root_cred.get_signature() is None:
+ # malformed
+ raise CredentialNotVerifiable(
+ "Could not verify credential owned by {} for object {}. "
+ "Cred has no signature"
+ .format(self.gidCaller.get_urn(), self.gidObject.get_urn()))
+
+ root_cred_signer = root_cred.get_signature().get_issuer_gid()
+
+ # Case 1:
+ # Allow non authority to sign target and cred about target.
+ #
+ # Why do we need to allow non authorities to sign?
+ # If in the target gid validation step we correctly
+ # checked that the target is only signed by an authority,
+ # then this is just a special case of case 3.
+ # This short-circuit is the common case currently -
+ # and cause GID validation doesn't check 'authority',
+ # this allows users to generate valid slice credentials.
+ if root_target_gid.is_signed_by_cert(root_cred_signer):
+ # cred signer matches target signer, return success
+ return
+
+ # Case 2:
+ # Allow someone to sign credential about themeselves. Used?
+ # If not, remove this.
+ # root_target_gid_str = root_target_gid.save_to_string()
+ # root_cred_signer_str = root_cred_signer.save_to_string()
+ # if root_target_gid_str == root_cred_signer_str:
+ # # cred signer is target, return success
+ # return
+
+ # Case 3:
+
+ # root_cred_signer is not the target_gid
+ # So this is a different gid that we have not verified.
+ # xmlsec1 verified the cert chain on this already, but
+ # it hasn't verified that the gid meets the HRN namespace
+ # requirements.
+ # Below we'll ensure that it is an authority.
+ # But we haven't verified that it is _signed by_ an authority
+ # We also don't know if xmlsec1 requires that cert signers
+ # are marked as CAs.
+
+ # Note that if verify() gave us no trusted_gids then this
+ # call will fail. So skip it if we have no trusted_gids
+ if trusted_gids and len(trusted_gids) > 0:
+ root_cred_signer.verify_chain(trusted_gids)
+ else:
+ logger.debug(
+ "Cannot verify that cred signer is signed by a trusted authority. "
+ "No trusted gids. Skipping that check.")
+
+ # See if the signer is an authority over the domain of the target.
+ # There are multiple types of authority - accept them all here
+ # Maybe should be (hrn, type) = urn_to_hrn(root_cred_signer.get_urn())
+ root_cred_signer_type = root_cred_signer.get_type()
+ if root_cred_signer_type.find('authority') == 0:
+ # logger.debug('Cred signer is an authority')
+ # signer is an authority, see if target is in authority's domain
+ signerhrn = root_cred_signer.get_hrn()
+ if hrn_authfor_hrn(signerhrn, root_target_gid.get_hrn()):
+ return
+
+ # We've required that the credential be signed by an authority
+ # for that domain. Reasonable and probably correct.
+ # A looser model would also allow the signer to be an authority
+ # in my control framework - eg My CA or CH. Even if it is not
+ # the CH that issued these, eg, user credentials.
+
+ # Give up, credential does not pass issuer verification
+
+ raise CredentialNotVerifiable(
+ "Could not verify credential owned by {} for object {}. "
+ "Cred signer {} not the trusted authority for Cred target {}"
+ .format(self.gidCaller.get_hrn(), self.gidObject.get_hrn(),
+ root_cred_signer.get_hrn(), root_target_gid.get_hrn()))
+
+ ##
+ # -- For Delegates (credentials with parents) verify that:
+ # . The privileges must be a subset of the parent credentials
+ # . The privileges must have "can_delegate" set for each delegated privilege
+ # . The target gid must be the same between child and parents
+ # . The expiry time on the child must be no later than the parent
+ # . The signer of the child must be the owner of the parent
+ def verify_parent(self, parent_cred):
+ # make sure the rights given to the child are a subset of the
+ # parents rights (and check delegate bits)
+ if not parent_cred.get_privileges().is_superset(self.get_privileges()):
+ message = (
+ "Parent cred {} (ref {}) rights {} "
+ " not superset of delegated cred {} (ref {}) rights {}"
+ .format(parent_cred.pretty_cred(), parent_cred.get_refid(),
+ parent_cred.get_privileges().pretty_rights(),
+ self.pretty_cred(), self.get_refid(),
+ self.get_privileges().pretty_rights()))
+ logger.error(message)
+ logger.error("parent details {}".format(
+ parent_cred.get_privileges().save_to_string()))
+ logger.error("self details {}".format(
+ self.get_privileges().save_to_string()))
+ raise ChildRightsNotSubsetOfParent(message)
+
+ # make sure my target gid is the same as the parent's
+ if not parent_cred.get_gid_object().save_to_string() == \
+ self.get_gid_object().save_to_string():
+ message = (
+ "Delegated cred {}: Target gid not equal between parent and child. Parent {}"
+ .format(self.pretty_cred(), parent_cred.pretty_cred()))
+ logger.error(message)
+ logger.error("parent details {}".format(
+ parent_cred.save_to_string()))
+ logger.error("self details {}".format(self.save_to_string()))
+ raise CredentialNotVerifiable(message)
+
+ # make sure my expiry time is <= my parent's
+ if not parent_cred.get_expiration() >= self.get_expiration():
+ raise CredentialNotVerifiable(
+ "Delegated credential {} expires after parent {}"
+ .format(self.pretty_cred(), parent_cred.pretty_cred()))
+
+ # make sure my signer is the parent's caller
+ if not parent_cred.get_gid_caller().save_to_string(False) == \
+ self.get_signature().get_issuer_gid().save_to_string(False):
+ message = "Delegated credential {} not signed by parent {}'s caller"\
+ .format(self.pretty_cred(), parent_cred.pretty_cred())
+ logger.error(message)
+ logger.error("compare1 parent {}".format(
+ parent_cred.get_gid_caller().pretty_cert()))
+ logger.error("compare1 parent details {}".format(
+ parent_cred.get_gid_caller().save_to_string()))
+ logger.error("compare2 self {}".format(
+ self.get_signature().get_issuer_gid().pretty_crert()))
+ logger.error("compare2 self details {}".format(
+ self.get_signature().get_issuer_gid().save_to_string()))
+ raise CredentialNotVerifiable(message)
+
+ # Recurse
+ if parent_cred.parent:
+ parent_cred.verify_parent(parent_cred.parent)
+
+ def delegate(self, delegee_gidfile, caller_keyfile, caller_gidfile):
+ """
+ Return a delegated copy of this credential, delegated to the
+ specified gid's user.
+ """
+ # get the gid of the object we are delegating
+ object_gid = self.get_gid_object()
+ object_hrn = object_gid.get_hrn()
+
+ # the hrn of the user who will be delegated to
+ delegee_gid = GID(filename=delegee_gidfile)
+ delegee_hrn = delegee_gid.get_hrn()
+
+ # user_key = Keypair(filename=keyfile)
+ # user_hrn = self.get_gid_caller().get_hrn()
+ subject_string = "{} delegated to {}".format(object_hrn, delegee_hrn)
+ dcred = Credential(subject=subject_string)
+ dcred.set_gid_caller(delegee_gid)
+ dcred.set_gid_object(object_gid)
+ dcred.set_parent(self)
+ dcred.set_expiration(self.get_expiration())
+ dcred.set_privileges(self.get_privileges())
+ dcred.get_privileges().delegate_all_privileges(True)
+ # dcred.set_issuer_keys(keyfile, delegee_gidfile)
+ dcred.set_issuer_keys(caller_keyfile, caller_gidfile)
+ dcred.encode()
+ dcred.sign()
+
+ return dcred
+
+ # only informative
+ def get_filename(self):
+ return getattr(self, 'filename', None)
+
+ def actual_caller_hrn(self):
+ """
+ a helper method used by some API calls like e.g. Allocate
+ to try and find out who really is the original caller
+
+ This admittedly is a bit of a hack, please USE IN LAST RESORT
+
+ This code uses a heuristic to identify a delegated credential
+
+ A first known restriction if for traffic that gets through a
+ slice manager in this case the hrn reported is the one from
+ the last SM in the call graph which is not at all what is
+ meant here
+ """
+
+ caller_hrn, caller_type = urn_to_hrn(self.get_gid_caller().get_urn())
+ issuer_hrn, issuer_type = urn_to_hrn(
+ self.get_signature().get_issuer_gid().get_urn())
+ subject_hrn = self.get_gid_object().get_hrn()
+ # if the caller is a user and the issuer is not
+ # it's probably the former
+ if caller_type == "user" and issuer_type != "user":
+ actual_caller_hrn = caller_hrn
+ # if we find that the caller_hrn is an immediate descendant
+ # of the issuer, then this seems to be a 'regular' credential
+ elif caller_hrn.startswith(issuer_hrn):
+ actual_caller_hrn = caller_hrn
+ # else this looks like a delegated credential, and the real caller is
+ # the issuer
+ else:
+ actual_caller_hrn = issuer_hrn
+ logger.info(
+ "actual_caller_hrn: caller_hrn={}, issuer_hrn={}, returning {}"
+ .format(caller_hrn, issuer_hrn, actual_caller_hrn))
+ return actual_caller_hrn
##
# Dump the contents of a credential to stdout in human-readable format
#
# @param dump_parents If true, also dump the parent certificates
+ def dump(self, *args, **kwargs):
+ print(self.dump_string(*args, **kwargs))
- def dump(self, dump_parents=False):
- print "CREDENTIAL", self.get_subject()
-
- print " privs:", self.get_privileges().save_to_string()
-
- print " gidCaller:"
+ # SFA code ignores show_xml and disables printing the cred xml
+ def dump_string(self, dump_parents=False, show_xml=False):
+ result = ""
+ result += "CREDENTIAL {}\n".format(self.pretty_subject())
+ filename = self.get_filename()
+ if filename:
+ result += "Filename {}\n".format(filename)
+ privileges = self.get_privileges()
+ if privileges:
+ result += " privs: {}\n".format(privileges.save_to_string())
+ else:
+ result += " privs: \n"
gidCaller = self.get_gid_caller()
if gidCaller:
- gidCaller.dump(8, dump_parents)
+ result += " gidCaller:\n"
+ result += gidCaller.dump_string(8, dump_parents)
+
+ if self.get_signature():
+ result += " gidIssuer:\n"
+ result += self.get_signature().get_issuer_gid()\
+ .dump_string(8, dump_parents)
+
+ if self.expiration:
+ result += " expiration: " + \
+ self.expiration.strftime(SFATIME_FORMAT) + "\n"
- print " gidObject:"
gidObject = self.get_gid_object()
if gidObject:
- gidObject.dump(8, dump_parents)
-
- print " delegate:", self.get_delegate()
+ result += " gidObject:\n"
+ result += gidObject.dump_string(8, dump_parents)
if self.parent and dump_parents:
- print "PARENT",
- self.parent.dump(dump_parents)
+ result += "\nPARENT"
+ result += self.parent.dump_string(True)
+
+ if show_xml and HAVELXML:
+ try:
+ tree = etree.parse(StringIO(self.xml))
+ aside = etree.tostring(tree, pretty_print=True)
+ result += "\nXML:\n\n"
+ result += aside
+ result += "\nEnd XML\n"
+ except:
+ import traceback
+ print("exc. Credential.dump_string / XML")
+ traceback.print_exc()
+ return result