requests-kerberos 0.9.0

A Kerberos authentication handler for python-requests

requests Kerberos/GSSAPI authentication library

Requests is an HTTP library, written in Python, for human beings. This library adds optional Kerberos/GSSAPI authentication support and supports mutual authentication. Basic GET usage:

>>> import requests
>>> from requests_kerberos import HTTPKerberosAuth
>>> r = requests.get("http://example.org", auth=HTTPKerberosAuth())
...

The entire requests.api should be supported.

Authentication Failures

Client authentication failures will be communicated to the caller by returning the 401 response.

Mutual Authentication

By default, HTTPKerberosAuth will require mutual authentication from the server, and if a server emits a non-error response which cannot be authenticated, a requests_kerberos.errors.MutualAuthenticationError will be raised. If a server emits an error which cannot be authenticated, it will be returned to the user but with its contents and headers stripped.

OPTIONAL

If you’d prefer to not require mutual authentication, you can set your preference when constructing your HTTPKerberosAuth object:

>>> import requests
>>> from requests_kerberos import HTTPKerberosAuth, OPTIONAL
>>> kerberos_auth = HTTPKerberosAuth(mutual_authentication=OPTIONAL)
>>> r = requests.get("http://example.org", auth=kerberos_auth)
...

This will cause requests_kerberos to attempt mutual authentication if the server advertises that it supports it, and cause a failure if authentication fails, but not if the server does not support it at all.

DISABLED

While we don’t recommend it, if you’d prefer to never attempt mutual authentication, you can do that as well:

>>> import requests
>>> from requests_kerberos import HTTPKerberosAuth, DISABLED
>>> kerberos_auth = HTTPKerberosAuth(mutual_authentication=DISABLED)
>>> r = requests.get("http://example.org", auth=kerberos_auth)
...

Preemptive Authentication

HTTPKerberosAuth can be forced to preemptively initiate the Kerberos GSS exchange and present a Kerberos ticket on the initial request (and all subsequent). By default, authentication only occurs after a 401 Unauthorized response containing a Kerberos or Negotiate challenge is received from the origin server. This can cause mutual authentication failures for hosts that use a persistent connection (eg, Windows/WinRM), as no Kerberos challenges are sent after the initial auth handshake. This behavior can be altered by setting force_preemptive=True:

>>> import requests
>>> from requests_kerberos import HTTPKerberosAuth, REQUIRED
>>> kerberos_auth = HTTPKerberosAuth(mutual_authentication=REQUIRED, force_preemptive=True)
>>> r = requests.get("https://windows.example.org/wsman", auth=kerberos_auth)
...

Hostname Override

If communicating with a host whose DNS name doesn’t match its kerberos hostname (eg, behind a content switch or load balancer), the hostname used for the Kerberos GSS exchange can be overridden by setting the hostname_override arg:

>>> import requests
>>> from requests_kerberos import HTTPKerberosAuth, REQUIRED
>>> kerberos_auth = HTTPKerberosAuth(hostname_override="internalhost.local")
>>> r = requests.get("https://externalhost.example.org/", auth=kerberos_auth)
...

Explicit Principal

HTTPKerberosAuth normally uses the default principal (ie, the user for whom you last ran kinit or kswitch, or an SSO credential if applicable). However, an explicit principal can be specified, which will cause Kerberos to look for a matching credential cache for the named user. This feature depends on OS support for collection-type credential caches, as well as working principal support in pykerberos (it is broken in many builds). An explicit principal can be specified with the principal arg:

>>> import requests
>>> from requests_kerberos import HTTPKerberosAuth, REQUIRED
>>> kerberos_auth = HTTPKerberosAuth(principal="user@REALM")
>>> r = requests.get("http://example.org", auth=kerberos_auth)
...

Logging

This library makes extensive use of Python’s logging facilities.

Log messages are logged to the requests_kerberos and requests_kerberos.kerberos_ named loggers.

If you are having difficulty we suggest you configure logging. Issues with the underlying kerberos libraries will be made apparent. Additionally, copious debug information is made available which may assist in troubleshooting if you increase your log level all the way up to debug.

History

0.9.0: 2016-05-06

• Support for principal, hostname, and realm override.

• Added support for mutual auth.

0.8.0: 2016-01-07

• Support for Kerberos delegation.

• Fixed problems declaring kerberos-sspi on Windows installs.

0.7.0: 2015-05-04

• Added Windows native authentication support by adding kerberos-sspi as an alternative backend.

• Prevent infinite recursion when a server returns 401 to an authorization attempt.

• Reduce the logging during successful responses.

0.6.1: 2014-11-14

• Fix HTTPKerberosAuth not to treat non-file as a file

• Prevent infinite recursion when GSSErrors occurs

0.6: 2014-11-04

• Handle mutual authentication (see pull request 36)

  All users should upgrade immediately. This has been reported to oss-security and we are awaiting a proper CVE identifier.

  Update: We were issued CVE-2014-8650

• Distribute as a wheel.

0.5: 2014-05-14

• Allow non-HTTP service principals with HTTPKerberosAuth using a new optional argument service.

• Fix bug in setup.py on distributions where the compiler module is not available.

• Add test dependencies to setup.py so python setup.py test will work.

0.4: 2013-10-26

• Minor updates in the README

• Change requirements to depend on requests above 1.1.0

0.3: 2013-06-02

• Work with servers operating on non-standard ports

0.2: 2013-03-26

• Not documented

0.1: Never released

• Initial Release