class Credential(object):
##
# 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 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):
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.legacy = None
# Check if this is a legacy credential, translate it if so
if string or filename:
if string:
str = string
elif filename:
str = file(filename).read()
if str.strip().startswith("-----"):
self.legacy = CredentialLegacy(False,string=str)
self.translate_legacy(str)
else:
self.xml = str
self.decode()
# Find an xmlsec1 path
self.xmlsec_path = ''
paths = ['/usr/bin','/usr/local/bin','/bin','/opt/bin','/opt/local/bin']
for path in paths:
if os.path.isfile(path + '/' + 'xmlsec1'):
self.xmlsec_path = path + '/' + 'xmlsec1'
break
if not self.xmlsec_path:
print "Could not locate binary for xmlsec1 - SFA will be unable to sign stuff !!"
def get_subject(self):
if not self.gidObject:
self.decode()
return self.gidObject.get_subject()
# sounds like this should be __repr__ instead ??
def get_summary_tostring(self):
if not self.gidObject:
self.decode()
obj = self.gidObject.get_printable_subject()
caller = self.gidCaller.get_printable_subject()
exp = self.get_expiration()
# Summarize the rights too? The issuer?
return "[ Grant %s rights on %s until %s ]" % (caller, obj, exp)
def get_signature(self):
if not self.signature:
self.decode()
return self.signature
def set_signature(self, sig):
self.signature = sig
##
# Translate a legacy credential into a new one
#
# @param String of the legacy credential
def translate_legacy(self, str):
legacy = CredentialLegacy(False,string=str)
self.gidCaller = legacy.get_gid_caller()
self.gidObject = legacy.get_gid_object()
lifetime = legacy.get_lifetime()
if not lifetime:
self.set_expiration(datetime.datetime.utcnow() + datetime.timedelta(seconds=DEFAULT_CREDENTIAL_LIFETIME))
else:
self.set_expiration(int(lifetime))
self.lifeTime = legacy.get_lifetime()
self.set_privileges(legacy.get_privileges())
self.get_privileges().delegate_all_privileges(legacy.get_delegate())
##
# 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
#
# @param gid GID object of the caller
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
def get_gid_caller(self):
if not self.gidCaller:
self.decode()
return self.gidCaller
##
# set the GID of the object
#
# @param gid GID object of the object
def set_gid_object(self, gid):
self.gidObject = gid
##
# get the GID of the object
def get_gid_object(self):
if not self.gidObject:
self.decode()
return self.gidObject
##
# Expiration: an absolute UTC time of expiration (as either an int or string or datetime)
#
def set_expiration(self, expiration):
if isinstance(expiration, (int, float)):
self.expiration = datetime.datetime.fromtimestamp(expiration)
elif isinstance (expiration, datetime.datetime):
self.expiration = expiration
elif isinstance (expiration, StringTypes):
self.expiration = utcparse (expiration)
else:
print "unexpected input type in Credential.set_expiration"
##
# get the lifetime of the credential (always in datetime format)
def get_expiration(self):
if not self.expiration:
self.decode()
# at this point self.expiration is normalized as a datetime - DON'T call utcparse again
return self.expiration
##
# For legacy sake
def get_lifetime(self):
return self.get_expiration()
##
# set the privileges
#
# @param privs either a comma-separated list of privileges of a Rights object
def set_privileges(self, privs):
if isinstance(privs, str):
self.privileges = Rights(string = privs)
else:
self.privileges = privs
##
# return the privileges as a Rights object
def get_privileges(self):
if not self.privileges:
self.decode()
return self.privileges
##
# determine whether the credential allows a particular operation to be
# performed
#
# @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 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):
# 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")
signed_cred.setAttribute("xsi:noNamespaceSchemaLocation", "http://www.planet-lab.org/resources/openflow.optin_manager.sfa.credential.xsd")
signed_cred.setAttribute("xsi:schemaLocation", "http://www.planet-lab.org/resources/openflow.optin_manager.sfa.ext/policy/1 http://www.planet-lab.org/resources/openflow.optin_manager.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 <credential> 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:
self.set_expiration(datetime.datetime.utcnow() + datetime.timedelta(seconds=DEFAULT_CREDENTIAL_LIFETIME))
self.expiration = self.expiration.replace(microsecond=0)
append_sub(doc, cred, "expires", self.expiration.isoformat())
privileges = doc.createElement("privileges")
cred.appendChild(privileges)
if self.privileges:
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 PLadd 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 %s to %s over %s replaced attribute %s value '%s' with '%s'" % (self.parent.gidCaller.get_urn(), self.gidCaller.get_urn(), self.gidObject.get_urn(), oldAttr.name, oldAttr.value, attr.value)
#raise CredentialNotVerifiable("Can't encode new valid delegated credential: %s" % 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 <signatures> 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()
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")
f.write(self.xml)
f.close()
def save_to_string(self, save_parents=True):
if not self.xml:
self.encode()
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
##
# 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%d" % (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:
print "Cannot sign credential (no private key)"
return
if not self.issuer_gid:
print "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()
# 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_%s' % self.get_refid()
filename = self.save_to_random_tmp_file()
command='%s --sign --node-id "%s" --privkey-pem %s,%s %s' \
% (self.xmlsec_path, ref, self.issuer_privkey, ",".join(gid_files), filename)
# print 'command',command
signed = os.popen(command).read()
os.remove(filename)
for gid_file in gid_files:
os.remove(gid_file)
self.xml = signed
# This is no longer a legacy credential
if self.legacy:
self.legacy = None
# 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):
if not self.xml:
return
doc = parseString(self.xml)
sigs = []
signed_cred = doc.getElementsByTagName("signed-credential")
# 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:
creds = doc.getElementsByTagName("credential")
if creds is None or len(creds) == 0:
# malformed cred file
raise CredentialNotVerifiable("Malformed XML: No credential tag found")
# 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"))
# Process privileges
privs = cred.getElementsByTagName("privileges")[0]
rlist = Rights()
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()
self.parent = Credential(string=parent_xml)
self.updateRefID()
# Assign the signatures to the credentials
for sig in sigs:
Sig = Signature(string=sig.toxml())
for cur_cred in self.get_credential_list():
if cur_cred.get_refid() == Sig.get_refid():
cur_cred.set_signature(Sig)
##
# 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
#
# -- 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 and not self.legacy:
if schema and os.path.exists(schema):
tree = etree.parse(StringIO(self.xml))
schema_doc = etree.parse(schema)
xmlschema = etree.XMLSchema(schema_doc)
#except Exception as e:
# print e
if not xmlschema:#.validate(tree):
error = xmlschema.error_log.last_error
message = "%s: %s (line %s)" % (self.get_summary_tostring(), error.message, error.line)
raise CredentialNotVerifiable(message)
if trusted_certs_required and trusted_certs is None:
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, exc:
print "Failed to load trusted cert from %s: %r" %(f, exc)
trusted_certs = ok_trusted_certs
# Use legacy verification if this is a legacy credential
if self.legacy:
self.legacy.verify_chain(trusted_cert_objects)
if self.legacy.client_gid:
self.legacy.client_gid.verify_chain(trusted_cert_objects)
if self.legacy.object_gid:
self.legacy.object_gid.verify_chain(trusted_cert_objects)
return True
# make sure it is not expired
if self.get_expiration() < datetime.datetime.utcnow():
raise CredentialNotVerifiable("Credential %s expired at %s" % (self.get_summary_tostring(), self.expiration.isoformat()))
# Verify the signatures
filename = self.save_to_random_tmp_file()
if trusted_certs is not None:
cert_args = " ".join(['--trusted-pem %s' % x for x in trusted_certs])
# If caller explicitly passed in None that means skip cert chain validation.
# - Strange and not typical
if trusted_certs is not None:
# Verify the gids of this cred and of its parents
for cur_cred in self.get_credential_list():
cur_cred.get_gid_object().verify_chain(trusted_cert_objects)
cur_cred.get_gid_caller().verify_chain(trusted_cert_objects)
refs = []
refs.append("Sig_%s" % self.get_refid())
parentRefs = self.updateRefID()
for ref in parentRefs:
refs.append("Sig_%s" % 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
# print "Doing %s --verify --node-id '%s' %s %s 2>&1" % \
# (self.xmlsec_path, ref, cert_args, filename)
verified = os.popen('%s --verify --node-id "%s" %s %s 2>&1' \
% (self.xmlsec_path, ref, cert_args, filename)).read()
if not verified.strip().startswith("OK"):
# 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]
raise CredentialNotVerifiable("xmlsec1 error verifying cred %s using Signature ID %s: %s %s" % (self.get_summary_tostring(), ref, msg, verified.strip()))
os.remove(filename)
# Verify the parents (delegation)
if self.parent:
self.verify_parent(self.parent)
# Make sure the issuer is the target's authority, and is
# itself a valid GID
self.verify_issuer(trusted_cert_objects)
return True