X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=sfa%2Ftrust%2Fcredential.py;h=d9368c4a54c109579da16ac06093ce1bb26a947e;hb=1cc8e9613cab8b5b22478de369f259e591c54e6d;hp=3268026d8300bd9fe36c4379c329e16532f22afe;hpb=8e2d56a95af339b291a4a79c13009606e22120d0;p=sfa.git diff --git a/sfa/trust/credential.py b/sfa/trust/credential.py index 3268026d..d9368c4a 100644 --- a/sfa/trust/credential.py +++ b/sfa/trust/credential.py @@ -26,64 +26,99 @@ # Credentials are signed XML files that assign a subject gid privileges to an object gid ## -### $Id$ -### $URL$ - import os +from types import StringTypes import datetime +from StringIO import StringIO from tempfile import mkstemp from xml.dom.minidom import Document, parseString -from dateutil.parser import parse -from lxml import etree -from StringIO import StringIO -from sfa.util.faults import * -from sfa.util.sfalogging import sfa_logger -from sfa.trust.certificate import Keypair + +HAVELXML = False +try: + from lxml import etree + HAVELXML = True +except: + pass + +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 from sfa.trust.credential_legacy import CredentialLegacy -from sfa.trust.rights import Right, Rights +from sfa.trust.rights import Right, Rights, determine_rights from sfa.trust.gid import GID -from sfa.util.xrn import urn_to_hrn +from sfa.util.xrn import urn_to_hrn, hrn_authfor_hrn # 2 weeks, in seconds -DEFAULT_CREDENTIAL_LIFETIME = 86400 * 14 +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_template = \ ''' - - - - + + + + - - - - - - - - - - - - + + + + + + + + + + + + ''' +# PG formats the template (whitespace) slightly differently. +# Note that they don't include the xmlns in the template, but add it later. +# Otherwise the two are equivalent. +#signature_template_as_in_pg = \ +#''' +# +# +# +# +# +# +# +# +# +# +# +# +# +# +# +# +# +# +# +# +# +# +#''' + ## # Convert a string into a bool - +# used to convert an xsd:boolean to a Python boolean def str2bool(str): - if str.lower() in ['yes','true','1']: + if str.lower() in ['true','1']: return True return False @@ -146,7 +181,11 @@ class Signature(object): self.gid = gid def decode(self): - doc = parseString(self.xml) + try: + doc = parseString(self.xml) + except ExpatError,e: + logger.log_exc ("Failed to parse credential, %s"%self.xml) + raise sig = doc.getElementsByTagName("Signature")[0] self.set_refid(sig.getAttribute("xml:id").strip("Sig_")) keyinfo = sig.getElementsByTagName("X509Data")[0] @@ -171,17 +210,19 @@ class Signature(object): # 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): +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.get_gid_caller().get_hrn() == caller_hrn: + if tmp_cred.get_gid_caller().get_hrn() in caller_hrn_list: caller_creds.append(cred) except: pass return caller_creds @@ -196,7 +237,7 @@ class Credential(object): # @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): + def __init__(self, create=False, subject=None, string=None, filename=None, cred=None): self.gidCaller = None self.gidObject = None self.expiration = None @@ -209,6 +250,19 @@ class Credential(object): self.xml = None self.refid = None self.legacy = None + self.type = None + self.version = None + + if cred: + if isinstance(cred, StringTypes): + string = cred + self.type = 'geni_sfa' + self.version = '1.0' + elif isinstance(cred, dict): + string = cred['geni_value'] + self.type = cred['geni_type'] + self.version = cred['geni_version'] + # Check if this is a legacy credential, translate it if so if string or filename: @@ -216,7 +270,6 @@ class Credential(object): str = string elif filename: str = file(filename).read() - self.filename=filename if str.strip().startswith("-----"): self.legacy = CredentialLegacy(False,string=str) @@ -234,9 +287,22 @@ class Credential(object): break def get_subject(self): + subject = "" + if not self.gidObject: + self.decode() + if self.gidObject: + subject = self.gidObject.get_printable_subject() + return subject + + # sounds like this should be __repr__ instead ?? + def get_summary_tostring(self): if not self.gidObject: self.decode() - return self.gidObject.get_subject() + 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: @@ -314,25 +380,28 @@ class Credential(object): if not self.gidObject: self.decode() return self.gidObject - - ## - # Expiration: an absolute UTC time of expiration (as either an int or datetime) + # Expiration: an absolute UTC time of expiration (as either an int or string or datetime) # def set_expiration(self, expiration): - if isinstance(expiration, int): + if isinstance(expiration, (int, float)): self.expiration = datetime.datetime.fromtimestamp(expiration) - else: + elif isinstance (expiration, datetime.datetime): self.expiration = expiration - + elif isinstance (expiration, StringTypes): + self.expiration = utcparse (expiration) + else: + logger.error ("unexpected input type in Credential.set_expiration") + ## - # get the lifetime of the credential (in datetime format) + # 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 ## @@ -349,8 +418,7 @@ class Credential(object): if isinstance(privs, str): self.privileges = Rights(string = privs) else: - self.privileges = privs - + self.privileges = privs ## # return the privileges as a Rights object @@ -387,6 +455,21 @@ class Credential(object): # 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/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 @@ -418,11 +501,55 @@ class Credential(object): # 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) + logger.warn(msg) + #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 tag signatures = doc.createElement("signatures") @@ -454,7 +581,6 @@ class Credential(object): f = open(filename, "w") f.write(self.xml) f.close() - self.filename=filename def save_to_string(self, save_parents=True): if not self.xml: @@ -570,22 +696,34 @@ class Credential(object): def decode(self): if not self.xml: return + + doc = None + try: + doc = parseString(self.xml) + except ExpatError,e: + raise CredentialNotVerifiable("Malformed credential") 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: - cred = signed_cred[0].getElementsByTagName("credential")[0] + creds = signed_cred[0].getElementsByTagName("credential") signatures = signed_cred[0].getElementsByTagName("signatures") if len(signatures) > 0: sigs = signatures[0].getElementsByTagName("Signature") else: - cred = doc.getElementsByTagName("credential")[0] + 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(parse(getTextNode(cred, "expires"))) + self.set_expiration(utcparse(getTextNode(cred, "expires"))) self.gidCaller = GID(string=getTextNode(cred, "owner_gid")) self.gidObject = GID(string=getTextNode(cred, "target_gid")) @@ -597,10 +735,12 @@ class Credential(object): kind = getTextNode(priv, "name") deleg = str2bool(getTextNode(priv, "can_delegate")) if kind == '*': - # Convert * into the default privileges for the credential's type + # 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 = rlist.determine_rights(type, 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)) @@ -628,6 +768,10 @@ class Credential(object): # 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 @@ -636,6 +780,7 @@ class Credential(object): # . 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) @@ -650,35 +795,39 @@ class Credential(object): # must be done elsewhere # # @param trusted_certs: The certificates of trusted CA certificates - # @param schema: The RelaxNG schema to validate the credential against - def verify(self, trusted_certs, schema=None): + def verify(self, trusted_certs=None, schema=None, trusted_certs_required=True): if not self.xml: - self.decode() - + self.decode() + # validate against RelaxNG schema - if not self.legacy: + 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) if not xmlschema.validate(tree): error = xmlschema.error_log.last_error - message = "%s (line %s)" % (error.message, error.line) - raise CredentialNotVerifiable(message) - + 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 = [GID(filename=f) for f in trusted_certs] trusted_cert_objects = [] ok_trusted_certs = [] - 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: - sfa_logger().error("Failed to load trusted cert from %s: %r", f, exc) - trusted_certs = 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: + logger.error("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: @@ -688,20 +837,23 @@ class Credential(object): 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 expired at %s" % self.expiration.isoformat()) + raise CredentialNotVerifiable("Credential %s expired at %s" % (self.get_summary_tostring(), self.expiration.isoformat())) # Verify the signatures filename = self.save_to_random_tmp_file() - cert_args = " ".join(['--trusted-pem %s' % x for x in trusted_certs]) + if trusted_certs is not None: + cert_args = " ".join(['--trusted-pem %s' % x for x in trusted_certs]) - # 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) + # 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()) @@ -711,18 +863,33 @@ class Credential(object): 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"): - raise CredentialNotVerifiable("xmlsec1 error verifying cert: " + verified) + # 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 - self.verify_issuer() + # Make sure the issuer is the target's authority, and is + # itself a valid GID + self.verify_issuer(trusted_cert_objects) return True ## @@ -740,31 +907,67 @@ class Credential(object): return list ## - # Make sure the credential's target gid was signed by (or is the same) the entity that signed - # the original credential or an authority over that namespace. - def verify_issuer(self): + # 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() 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 - 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 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("No trusted gids. Cannot verify that cred signer is signed by a trusted authority. Skipping that check.") - # See if it the signer is an authority over the domain of the target + # 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 == 'authority'): - #sfa_logger().debug('Cred signer is an authority') + 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 - hrn = root_cred_signer.get_hrn() - if root_target_gid.get_hrn().startswith(hrn): + 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 @@ -789,23 +992,23 @@ class Credential(object): # 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()): - raise ChildRightsNotSubsetOfParent( - self.parent.get_privileges().save_to_string() + " " + + raise ChildRightsNotSubsetOfParent(("Parent cred ref %s rights " % parent_cred.get_refid()) + + self.parent.get_privileges().save_to_string() + (" not superset of delegated cred %s ref %s rights " % (self.get_summary_tostring(), self.get_refid())) + self.get_privileges().save_to_string()) # 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(): - raise CredentialNotVerifiable("Target gid not equal between parent and child") + raise CredentialNotVerifiable("Delegated cred %s: Target gid not equal between parent and child. Parent %s" % (self.get_summary_tostring(), parent_cred.get_summary_tostring())) # 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") + raise CredentialNotVerifiable("Delegated credential %s expires after parent %s" % (self.get_summary_tostring(), parent_cred.get_summary_tostring())) # 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): - raise CredentialNotVerifiable("Delegated credential not signed by parent caller") + raise CredentialNotVerifiable("Delegated credential %s not signed by parent %s's caller" % (self.get_summary_tostring(), parent_cred.get_summary_tostring())) # Recurse if parent_cred.parent: @@ -840,34 +1043,49 @@ class Credential(object): dcred.encode() dcred.sign() - return dcred + return dcred # only informative def get_filename(self): return getattr(self,'filename',None) + ## + # 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_string(self, dump_parents=False): result="" - result += "CREDENTIAL %s\n" % self.get_subject() + result += "CREDENTIAL %s\n" % self.get_subject() filename=self.get_filename() if filename: result += "Filename %s\n"%filename - result += " privs: %s\n" % self.get_privileges().save_to_string() + privileges = self.get_privileges() + if privileges: + result += " privs: %s\n" % privileges.save_to_string() + else: + result += " privs: \n" gidCaller = self.get_gid_caller() if gidCaller: result += " gidCaller:\n" result += gidCaller.dump_string(8, dump_parents) + if self.get_signature(): + print " gidIssuer:" + self.get_signature().get_issuer_gid().dump(8, dump_parents) + + if self.expiration: + print " expiration:", self.expiration.isoformat() + gidObject = self.get_gid_object() if gidObject: result += " gidObject:\n" result += gidObject.dump_string(8, dump_parents) if self.parent and dump_parents: - result += "PARENT" - result += self.parent.dump_string(dump_parents) - return result + result += "\nPARENT" + result += self.parent.dump_string(True) + return result