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from __future__ import print_function
import logging
import urllib2
import kerberos as krb
import re
RGX = re.compile(r"(?:.*,)*\s*Negotiate\s*([^,]*),?", re.I)
class GssapiAuthError(Exception):
"""raised on error during authentication process"""
def get_negociate_value(headers):
for authreq in headers.getheaders("www-authenticate"):
match = RGX.search(authreq)
if match:
return match.group(1)
class HTTPGssapiAuthHandler(urllib2.BaseHandler):
"""Negotiate HTTP authentication using context from GSSAPI"""
handler_order = 400 # before Digest Auth
def __init__(self):
self._reset()
def _reset(self):
self._retried = 0
self._context = None
def clean_context(self):
if self._context is not None:
krb.authGSSClientClean(self._context)
def http_error_401(self, req, fp, code, msg, headers):
try:
if self._retried > 5:
raise urllib2.HTTPError(
req.get_full_url(), 401, "negotiate auth failed", headers, None
)
self._retried += 1
logging.debug("gssapi handler, try %s" % self._retried)
negotiate = get_negociate_value(headers)
if negotiate is None:
logging.debug("no negociate found in a www-authenticate header")
return None
logging.debug("HTTPGssapiAuthHandler: negotiate 1 is %r" % negotiate)
result, self._context = krb.authGSSClientInit("HTTP@%s" % req.get_host())
if result < 1:
raise GssapiAuthError("HTTPGssapiAuthHandler: init failed with %d" % result)
result = krb.authGSSClientStep(self._context, negotiate)
if result < 0:
raise GssapiAuthError("HTTPGssapiAuthHandler: step 1 failed with %d" % result)
client_response = krb.authGSSClientResponse(self._context)
logging.debug("HTTPGssapiAuthHandler: client response is %s..." % client_response[:10])
req.add_unredirected_header("Authorization", "Negotiate %s" % client_response)
server_response = self.parent.open(req)
negotiate = get_negociate_value(server_response.info())
if negotiate is None:
logging.warning("HTTPGssapiAuthHandler: failed to authenticate server")
else:
logging.debug("HTTPGssapiAuthHandler negotiate 2: %s" % negotiate)
result = krb.authGSSClientStep(self._context, negotiate)
if result < 1:
raise GssapiAuthError("HTTPGssapiAuthHandler: step 2 failed with %d" % result)
return server_response
except GssapiAuthError as exc:
logging.error(repr(exc))
finally:
self.clean_context()
self._reset()
if __name__ == "__main__":
import sys
# debug
import httplib
httplib.HTTPConnection.debuglevel = 1
httplib.HTTPSConnection.debuglevel = 1
logging.basicConfig(level=logging.DEBUG)
# handle cookies
import cookielib
cj = cookielib.CookieJar()
ch = urllib2.HTTPCookieProcessor(cj)
# test with url sys.argv[1]
h = HTTPGssapiAuthHandler()
response = urllib2.build_opener(h, ch).open(sys.argv[1])
print("\nresponse: %s\n--------------\n" % response.code, response.info())
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