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#!/usr/bin/env python
#
# duo_openvpn.py
# Duo OpenVPN v1
# Copyright 2011 Duo Security, Inc.
#
import os, sys, urllib, hashlib, httplib, hmac, base64, json, syslog
API_RESULT_AUTH = 'auth'
API_RESULT_ALLOW = 'allow'
API_RESULT_DENY = 'deny'
API_RESULT_ENROLL = 'enroll'
def canonicalize(method, host, uri, params):
canon = [method.upper(), host.lower(), uri]
args = []
for key in sorted(params.keys()):
val = params[key]
arg = '%s=%s' % (urllib.quote(key, '~'), urllib.quote(val, '~'))
args.append(arg)
canon.append('&'.join(args))
return '\n'.join(canon)
def sign(ikey, skey, method, host, uri, params):
sig = hmac.new(skey, canonicalize(method, host, uri, params), hashlib.sha1)
auth = '%s:%s' % (ikey, sig.hexdigest())
return 'Basic %s' % base64.b64encode(auth)
def call(ikey, skey, host, method, path, **kwargs):
headers = {'Authorization':sign(ikey, skey, method, host, path, kwargs)}
if method in [ 'POST', 'PUT' ]:
headers['Content-type'] = 'application/x-www-form-urlencoded'
body = urllib.urlencode(kwargs, doseq=True)
uri = path
else:
body = None
uri = path + '?' + urllib.urlencode(kwargs, doseq=True)
conn = httplib.HTTPSConnection(host, 443)
conn.request(method, uri, body, headers)
response = conn.getresponse()
data = response.read()
conn.close()
return (response.status, response.reason, data)
def api(ikey, skey, host, method, path, **kwargs):
(status, reason, data) = call(ikey, skey, host, method, path, **kwargs)
if status != 200:
raise RuntimeError('Received %s %s: %s' % (status, reason, data))
try:
data = json.loads(data)
if data['stat'] != 'OK':
raise RuntimeError('Received error response: %s' % data)
return data['response']
except (ValueError, KeyError):
raise RuntimeError('Received bad response: %s' % data)
def log(msg):
msg = 'Duo OpenVPN: %s' % msg
syslog.syslog(msg)
def success(control):
log('writing success code to %s' % control)
f = open(control, 'w')
f.write('1')
f.close()
sys.exit(0)
def failure(control):
log('writing failure code to %s' % control)
f = open(control, 'w')
f.write('0')
f.close()
sys.exit(1)
def preauth(ikey, skey, host, control, username):
log('pre-authentication for %s' % username)
args = {
'user': username,
}
response = api(ikey, skey, host, 'POST', '/rest/v1/preauth', **args)
result = response.get('result')
if not result:
log('invalid API response: %s' % response)
failure(control)
if result == API_RESULT_AUTH:
return
status = response.get('status')
if not status:
log('invalid API response: %s' % response)
failure(control)
if result == API_RESULT_ENROLL:
log('user %s is not enrolled: %s' % (username, status))
failure(control)
elif result == API_RESULT_DENY:
log('preauth failure for %s: %s' % (username, status))
failure(control)
elif result == API_RESULT_ALLOW:
log('preauth success for %s: %s' % (username, status))
success(control)
else:
log('unknown preauth result: %s' % result)
failure(control)
def auth(ikey, skey, host, control, username, password, ipaddr):
log('authentication for %s' % username)
args = {
'user': username,
'factor': 'auto',
'auto': password,
'ipaddr': ipaddr
}
response = api(ikey, skey, host, 'POST', '/rest/v1/auth', **args)
result = response.get('result')
status = response.get('status')
if not result or not status:
log('invalid API response: %s' % response)
failure(control)
if result == API_RESULT_ALLOW:
log('auth success for %s: %s' % (username, status))
success(control)
elif result == API_RESULT_DENY:
log('auth failure for %s: %s' % (username, status))
failure(control)
else:
log('unknown auth result: %s' % result)
failure(control)
def main():
ikey = os.environ.get('ikey')
skey = os.environ.get('skey')
host = os.environ.get('host')
if not ikey or not skey or not host:
log('required ikey/skey/host configuration parameters not found')
failure(control)
control = os.environ.get('control')
username = os.environ.get('username')
password = os.environ.get('password')
ipaddr = os.environ.get('ipaddr', '0.0.0.0')
if not control or not username or not password:
log('required environment variables not found')
failure(control)
try:
preauth(ikey, skey, host, control, username)
except Exception, e:
log(str(e))
failure(control)
try:
auth(ikey, skey, host, control, username, password, ipaddr)
except Exception, e:
log(str(e))
failure(control)
failure(control)
if __name__ == '__main__':
main()
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