X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=sfa%2Ftrust%2Fspeaksfor_util.py;fp=sfa%2Ftrust%2Fspeaksfor_util.py;h=bd121951d8beafd64f506eebb9e113fafdb085be;hb=93c4c358fd8b0cd49cb2ece9c58737b883790482;hp=0000000000000000000000000000000000000000;hpb=413e217f33fe4a6148bba4edd8a761087bb22c12;p=sfa.git
diff --git a/sfa/trust/speaksfor_util.py b/sfa/trust/speaksfor_util.py
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+#----------------------------------------------------------------------
+# Copyright (c) 2014 Raytheon BBN Technologies
+#
+# 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.
+#----------------------------------------------------------------------
+
+import datetime
+from dateutil import parser as du_parser, tz as du_tz
+import optparse
+import os
+import subprocess
+import sys
+import tempfile
+from xml.dom.minidom import *
+from StringIO import StringIO
+
+from sfa.trust.certificate import Certificate
+from sfa.trust.credential import Credential, signature_template, HAVELXML
+from sfa.trust.abac_credential import ABACCredential, ABACElement
+from sfa.trust.credential_factory import CredentialFactory
+from sfa.trust.gid import GID
+
+# Routine to validate that a speaks-for credential
+# says what it claims to say:
+# It is a signed credential wherein the signer S is attesting to the
+# ABAC statement:
+# S.speaks_for(S)<-T Or "S says that T speaks for S"
+
+# Requires that openssl be installed and in the path
+# create_speaks_for requires that xmlsec1 be on the path
+
+# Simple XML helper functions
+
+# Find the text associated with first child text node
+def findTextChildValue(root):
+ child = findChildNamed(root, '#text')
+ if child: return str(child.nodeValue)
+ return None
+
+# Find first child with given name
+def findChildNamed(root, name):
+ for child in root.childNodes:
+ if child.nodeName == name:
+ return child
+ return None
+
+# Write a string to a tempfile, returning name of tempfile
+def write_to_tempfile(str):
+ str_fd, str_file = tempfile.mkstemp()
+ if str:
+ os.write(str_fd, str)
+ os.close(str_fd)
+ return str_file
+
+# Run a subprocess and return output
+def run_subprocess(cmd, stdout, stderr):
+ try:
+ proc = subprocess.Popen(cmd, stdout=stdout, stderr=stderr)
+ proc.wait()
+ if stdout:
+ output = proc.stdout.read()
+ else:
+ output = proc.returncode
+ return output
+ except Exception as e:
+ raise Exception("Failed call to subprocess '%s': %s" % (" ".join(cmd), e))
+
+def get_cert_keyid(gid):
+ """Extract the subject key identifier from the given certificate.
+ Return they key id as lowercase string with no colon separators
+ between pairs. The key id as shown in the text output of a
+ certificate are in uppercase with colon separators.
+
+ """
+ raw_key_id = gid.get_extension('subjectKeyIdentifier')
+ # Raw has colons separating pairs, and all characters are upper case.
+ # Remove the colons and convert to lower case.
+ keyid = raw_key_id.replace(':', '').lower()
+ return keyid
+
+# Pull the cert out of a list of certs in a PEM formatted cert string
+def grab_toplevel_cert(cert):
+ start_label = '-----BEGIN CERTIFICATE-----'
+ if cert.find(start_label) > -1:
+ start_index = cert.find(start_label) + len(start_label)
+ else:
+ start_index = 0
+ end_label = '-----END CERTIFICATE-----'
+ end_index = cert.find(end_label)
+ first_cert = cert[start_index:end_index]
+ pieces = first_cert.split('\n')
+ first_cert = "".join(pieces)
+ return first_cert
+
+# Validate that the given speaks-for credential represents the
+# statement User.speaks_for(User)<-Tool for the given user and tool certs
+# and was signed by the user
+# Return:
+# Boolean indicating whether the given credential
+# is not expired
+# is an ABAC credential
+# was signed by the user associated with the speaking_for_urn
+# is verified by xmlsec1
+# asserts U.speaks_for(U)<-T ("user says that T may speak for user")
+# If schema provided, validate against schema
+# is trusted by given set of trusted roots (both user cert and tool cert)
+# String user certificate of speaking_for user if the above tests succeed
+# (None otherwise)
+# Error message indicating why the speaks_for call failed ("" otherwise)
+def verify_speaks_for(cred, tool_gid, speaking_for_urn, \
+ trusted_roots, schema=None, logger=None):
+
+ # Credential has not expired
+ if cred.expiration and cred.expiration < datetime.datetime.utcnow():
+ return False, None, "ABAC Credential expired at %s (%s)" % (cred.expiration.isoformat(), cred.get_summary_tostring())
+
+ # Must be ABAC
+ if cred.get_cred_type() != ABACCredential.ABAC_CREDENTIAL_TYPE:
+ return False, None, "Credential not of type ABAC but %s" % cred.get_cred_type
+
+ if cred.signature is None or cred.signature.gid is None:
+ return False, None, "Credential malformed: missing signature or signer cert. Cred: %s" % cred.get_summary_tostring()
+ user_gid = cred.signature.gid
+ user_urn = user_gid.get_urn()
+
+ # URN of signer from cert must match URN of 'speaking-for' argument
+ if user_urn != speaking_for_urn:
+ return False, None, "User URN from cred doesn't match speaking_for URN: %s != %s (cred %s)" % \
+ (user_urn, speaking_for_urn, cred.get_summary_tostring())
+
+ tails = cred.get_tails()
+ if len(tails) != 1:
+ return False, None, "Invalid ABAC-SF credential: Need exactly 1 tail element, got %d (%s)" % \
+ (len(tails), cred.get_summary_tostring())
+
+ user_keyid = get_cert_keyid(user_gid)
+ tool_keyid = get_cert_keyid(tool_gid)
+ subject_keyid = tails[0].get_principal_keyid()
+
+ head = cred.get_head()
+ principal_keyid = head.get_principal_keyid()
+ role = head.get_role()
+
+ logger.info('user keyid: %s' % user_keyid)
+ logger.info('principal keyid: %s' % principal_keyid)
+ logger.info('tool keyid: %s' % tool_keyid)
+ logger.info('subject keyid: %s' % subject_keyid)
+ logger.info('role: %s' % role)
+ logger.info('user gid: %s' % user_gid.dump_string())
+ f = open('/tmp/speaksfor/tool.gid', 'w')
+ f.write(tool_gid.dump_string())
+ f.close()
+
+ # Credential must pass xmlsec1 verify
+ cred_file = write_to_tempfile(cred.save_to_string())
+ cert_args = []
+ if trusted_roots:
+ for x in trusted_roots:
+ cert_args += ['--trusted-pem', x.filename]
+ # FIXME: Why do we not need to specify the --node-id option as credential.py does?
+ xmlsec1_args = [cred.xmlsec_path, '--verify'] + cert_args + [ cred_file]
+ output = run_subprocess(xmlsec1_args, stdout=None, stderr=subprocess.PIPE)
+ os.unlink(cred_file)
+ if output != 0:
+ # FIXME
+ # xmlsec errors have a msg= which is the interesting bit.
+ # But does this go to stderr or stdout? Do we have it here?
+ mstart = verified.find("msg=")
+ msg = ""
+ if mstart > -1 and len(verified) > 4:
+ mstart = mstart + 4
+ mend = verified.find('\\', mstart)
+ msg = verified[mstart:mend]
+ if msg == "":
+ msg = output
+ return False, None, "ABAC credential failed to xmlsec1 verify: %s" % msg
+
+ # Must say U.speaks_for(U)<-T
+ if user_keyid != principal_keyid or \
+ tool_keyid != subject_keyid or \
+ role != ('speaks_for_%s' % user_keyid):
+ return False, None, "ABAC statement doesn't assert U.speaks_for(U)<-T (%s)" % cred.get_summary_tostring()
+
+ # If schema provided, validate against schema
+ if HAVELXML and schema and os.path.exists(schema):
+ from lxml import etree
+ tree = etree.parse(StringIO(cred.xml))
+ schema_doc = etree.parse(schema)
+ xmlschema = etree.XMLSchema(schema_doc)
+ if not xmlschema.validate(tree):
+ error = xmlschema.error_log.last_error
+ message = "%s: %s (line %s)" % (cred.get_summary_tostring(), error.message, error.line)
+ return False, None, ("XML Credential schema invalid: %s" % message)
+
+ if trusted_roots:
+ # User certificate must validate against trusted roots
+ try:
+ user_gid.verify_chain(trusted_roots)
+ except Exception, e:
+ return False, None, \
+ "Cred signer (user) cert not trusted: %s" % e
+
+ # Tool certificate must validate against trusted roots
+ try:
+ tool_gid.verify_chain(trusted_roots)
+ except Exception, e:
+ return False, None, \
+ "Tool cert not trusted: %s" % e
+
+ return True, user_gid, ""
+
+# Determine if this is a speaks-for context. If so, validate
+# And return either the tool_cert (not speaks-for or not validated)
+# or the user cert (validated speaks-for)
+#
+# credentials is a list of GENI-style credentials:
+# Either a cred string xml string, or Credential object of a tuple
+# [{'geni_type' : geni_type, 'geni_value : cred_value,
+# 'geni_version' : version}]
+# caller_gid is the raw X509 cert gid
+# options is the dictionary of API-provided options
+# trusted_roots is a list of Certificate objects from the system
+# trusted_root directory
+# Optionally, provide an XML schema against which to validate the credential
+def determine_speaks_for(logger, credentials, caller_gid, options, \
+ trusted_roots, schema=None):
+ logger.info(options)
+ logger.info("geni speaking for:%s " % 'geni_speaking_for' in options)
+ if options and 'geni_speaking_for' in options:
+ speaking_for_urn = options['geni_speaking_for'].strip()
+ for cred in credentials:
+ # Skip things that aren't ABAC credentials
+ if type(cred) == dict:
+ if cred['geni_type'] != ABACCredential.ABAC_CREDENTIAL_TYPE: continue
+ cred_value = cred['geni_value']
+ elif isinstance(cred, Credential):
+ if not isinstance(cred, ABACCredential):
+ continue
+ else:
+ cred_value = cred
+ else:
+ if CredentialFactory.getType(cred) != ABACCredential.ABAC_CREDENTIAL_TYPE: continue
+ cred_value = cred
+
+ # If the cred_value is xml, create the object
+ if not isinstance(cred_value, ABACCredential):
+ cred = CredentialFactory.createCred(cred_value)
+
+# print "Got a cred to check speaksfor for: %s" % cred.get_summary_tostring()
+# #cred.dump(True, True)
+# print "Caller: %s" % caller_gid.dump_string(2, True)
+ logger.info(cred.dump_string())
+ f = open('/tmp/speaksfor/%s.cred' % cred, 'w')
+ f.write(cred.xml)
+ f.close()
+ # See if this is a valid speaks_for
+ is_valid_speaks_for, user_gid, msg = \
+ verify_speaks_for(cred,
+ caller_gid, speaking_for_urn, \
+ trusted_roots, schema, logger=logger)
+ logger.info(msg)
+ if is_valid_speaks_for:
+ return user_gid # speaks-for
+ else:
+ if logger:
+ logger.info("Got speaks-for option but not a valid speaks_for with this credential: %s" % msg)
+ else:
+ print "Got a speaks-for option but not a valid speaks_for with this credential: " + msg
+ return caller_gid # Not speaks-for
+
+# Create an ABAC Speaks For credential using the ABACCredential object and it's encode&sign methods
+def create_sign_abaccred(tool_gid, user_gid, ma_gid, user_key_file, cred_filename, dur_days=365):
+ print "Creating ABAC SpeaksFor using ABACCredential...\n"
+ # Write out the user cert
+ from tempfile import mkstemp
+ ma_str = ma_gid.save_to_string()
+ user_cert_str = user_gid.save_to_string()
+ if not user_cert_str.endswith(ma_str):
+ user_cert_str += ma_str
+ fp, user_cert_filename = mkstemp(suffix='cred', text=True)
+ fp = os.fdopen(fp, "w")
+ fp.write(user_cert_str)
+ fp.close()
+
+ # Create the cred
+ cred = ABACCredential()
+ cred.set_issuer_keys(user_key_file, user_cert_filename)
+ tool_urn = tool_gid.get_urn()
+ user_urn = user_gid.get_urn()
+ user_keyid = get_cert_keyid(user_gid)
+ tool_keyid = get_cert_keyid(tool_gid)
+ cred.head = ABACElement(user_keyid, user_urn, "speaks_for_%s" % user_keyid)
+ cred.tails.append(ABACElement(tool_keyid, tool_urn))
+ cred.set_expiration(datetime.datetime.utcnow() + datetime.timedelta(days=dur_days))
+ cred.expiration = cred.expiration.replace(microsecond=0)
+
+ # Produce the cred XML
+ cred.encode()
+
+ # Sign it
+ cred.sign()
+ # Save it
+ cred.save_to_file(cred_filename)
+ print "Created ABAC credential: '%s' in file %s" % \
+ (cred.get_summary_tostring(), cred_filename)
+
+# FIXME: Assumes xmlsec1 is on path
+# FIXME: Assumes signer is itself signed by an 'ma_gid' that can be trusted
+def create_speaks_for(tool_gid, user_gid, ma_gid, \
+ user_key_file, cred_filename, dur_days=365):
+ tool_urn = tool_gid.get_urn()
+ user_urn = user_gid.get_urn()
+
+ header = ''
+ reference = "ref0"
+ signature_block = \
+ '\n' + \
+ signature_template + \
+ ''
+ template = header + '\n' + \
+ '\n' + \
+ '\n' + \
+ 'abac\n' + \
+ '\n' +\
+ '\n' + \
+ '\n' + \
+ '\n' + \
+ '\n' + \
+ '\n' + \
+ '%s' +\
+ '\n' + \
+ '\n' + \
+ '%s\n' + \
+ '\n' + \
+ '%s%s\n' +\
+ 'speaks_for_%s\n' + \
+ '\n' + \
+ '\n' +\
+ '%s%s\n' +\
+ '\n' +\
+ '\n' + \
+ '\n' + \
+ '\n' + \
+ signature_block + \
+ '\n'
+
+
+ credential_duration = datetime.timedelta(days=dur_days)
+ expiration = datetime.datetime.now(du_tz.tzutc()) + credential_duration
+ expiration_str = expiration.strftime('%Y-%m-%dT%H:%M:%SZ') # FIXME: libabac can't handle .isoformat()
+ version = "1.1"
+
+ user_keyid = get_cert_keyid(user_gid)
+ tool_keyid = get_cert_keyid(tool_gid)
+ unsigned_cred = template % (reference, expiration_str, version, \
+ user_keyid, user_urn, user_keyid, tool_keyid, tool_urn, \
+ reference, reference)
+ unsigned_cred_filename = write_to_tempfile(unsigned_cred)
+
+ # Now sign the file with xmlsec1
+ # xmlsec1 --sign --privkey-pem privkey.pem,cert.pem
+ # --output signed.xml tosign.xml
+ pems = "%s,%s,%s" % (user_key_file, user_gid.get_filename(),
+ ma_gid.get_filename())
+ # FIXME: assumes xmlsec1 is on path
+ cmd = ['xmlsec1', '--sign', '--privkey-pem', pems,
+ '--output', cred_filename, unsigned_cred_filename]
+
+# print " ".join(cmd)
+ sign_proc_output = run_subprocess(cmd, stdout=subprocess.PIPE, stderr=None)
+ if sign_proc_output == None:
+ print "OUTPUT = %s" % sign_proc_output
+ else:
+ print "Created ABAC credential: '%s speaks_for %s' in file %s" % \
+ (tool_urn, user_urn, cred_filename)
+ os.unlink(unsigned_cred_filename)
+
+
+# Test procedure
+if __name__ == "__main__":
+
+ parser = optparse.OptionParser()
+ parser.add_option('--cred_file',
+ help='Name of credential file')
+ parser.add_option('--tool_cert_file',
+ help='Name of file containing tool certificate')
+ parser.add_option('--user_urn',
+ help='URN of speaks-for user')
+ parser.add_option('--user_cert_file',
+ help="filename of x509 certificate of signing user")
+ parser.add_option('--ma_cert_file',
+ help="filename of x509 cert of MA that signed user cert")
+ parser.add_option('--user_key_file',
+ help="filename of private key of signing user")
+ parser.add_option('--trusted_roots_directory',
+ help='Directory of trusted root certs')
+ parser.add_option('--create',
+ help="name of file of ABAC speaksfor cred to create")
+ parser.add_option('--useObject', action='store_true', default=False,
+ help='Use the ABACCredential object to create the credential (default False)')
+
+ options, args = parser.parse_args(sys.argv)
+
+ tool_gid = GID(filename=options.tool_cert_file)
+
+ if options.create:
+ if options.user_cert_file and options.user_key_file \
+ and options.ma_cert_file:
+ user_gid = GID(filename=options.user_cert_file)
+ ma_gid = GID(filename=options.ma_cert_file)
+ if options.useObject:
+ create_sign_abaccred(tool_gid, user_gid, ma_gid, \
+ options.user_key_file, \
+ options.create)
+ else:
+ create_speaks_for(tool_gid, user_gid, ma_gid, \
+ options.user_key_file, \
+ options.create)
+ else:
+ print "Usage: --create cred_file " + \
+ "--user_cert_file user_cert_file" + \
+ " --user_key_file user_key_file --ma_cert_file ma_cert_file"
+ sys.exit()
+
+ user_urn = options.user_urn
+
+ # Get list of trusted rootcerts
+ if options.cred_file and not options.trusted_roots_directory:
+ sys.exit("Must supply --trusted_roots_directory to validate a credential")
+
+ trusted_roots_directory = options.trusted_roots_directory
+ trusted_roots = \
+ [Certificate(filename=os.path.join(trusted_roots_directory, file)) \
+ for file in os.listdir(trusted_roots_directory) \
+ if file.endswith('.pem') and file != 'CATedCACerts.pem']
+
+ cred = open(options.cred_file).read()
+
+ creds = [{'geni_type' : ABACCredential.ABAC_CREDENTIAL_TYPE, 'geni_value' : cred,
+ 'geni_version' : '1'}]
+ gid = determine_speaks_for(None, creds, tool_gid, \
+ {'geni_speaking_for' : user_urn}, \
+ trusted_roots)
+
+
+ print 'SPEAKS_FOR = %s' % (gid != tool_gid)
+ print "CERT URN = %s" % gid.get_urn()