Run a OCSP responder¶
OCSP, or the Online Certificate Status Protocol provides a second method (besides CRLs) for a client to find out if a certificate has been revoked.
Warning
The OCSP responder included in django-ca is still very experimental. Expect problems when using it. Please also expect major changes in how it is configured in future versions.
Configure OCSP with django-ca¶
django-ca provides generic HTTP endpoints for an OCSP service for your certificate authorities. The setup involves:
New in version 1.2: Before version 1.2, django-ca was not able to host its own OCSP responder.
Create an OCSP responser certificate¶
To run an OCSP responder, you first need a certificate with some special properties. Luckily, django-ca has a profile predefined for you:
$ openssl genrsa -out ocsp.key 4096
$ openssl req -new -key ocsp.key -out ocsp.csr -utf8 -batch
$ python manage.py sign_cert --csr=ocsp.csr --out=ocsp.pem \
> --subject /CN=ocsp.example.com --ocsp
Warning
The CommonName in the certificates subject must match the domain where you host your django-ca installation.
Configure generic views¶
The final step in configuring an OCSP responder for the CA is configuring the HTTP endpoint. If
you’ve installed django-ca as a full project or include django_ca.urls
in your root URL config,
configure the CA_OCSP_URLS
setting. It’s a dictionary configuring instances of
OCSPView
. Keys become part of the URL pattern, the value is a
dictionary for the arguments of the view. For example:
CA_OCSP_URLS = {
'root': {
'ca': '34:D6:02:B5:B8:27:4F:51:9A:16:0C:B8:56:B7:79:3F',
'responder_key': '/usr/share/django-ca/ocsp.key',
'responder_cert': 'F2:5F:7F:31:E1:91:4F:D7:9A:D4:19:65:17:3D:43:88',
# optional: How long OCSP responses are valid
#'expires': 3600,
},
}
This would mean that your OCSP responder would be located at /django_ca/ocsp/root/
at whatever
domain you have configured your WSGI daemon. If you’re using your own URL configuration, pass the
same parameters to the as_view()
method.
-
class
django_ca.views.
OCSPView
(**kwargs)[source]¶ View to provide an OCSP responder.
See also
This is heavily inspired by https://github.com/threema-ch/ocspresponder/blob/master/ocspresponder/__init__.py.
-
ca
= None¶ The serial of your certificate authority.
-
expires
= 600¶ Time in seconds that the responses remain valid. The default is 600 seconds or ten minutes.
-
responder_cert
= None¶ Absolute path or key itself used for signing OCSP responses.
-
responder_key
= None¶ Absolute path to the private key used for signing OCSP responses.
-
Add OCSP URL to new certificates¶
To include the URL to an OCSP service to newly issued certificates (you cannot add it to already issued certificates, obviously), either set it in the admin interface or via the command line:
$ python manage.py list_cas
34:D6:02:B5:B8:27:4F:51:9A:16:0C:B8:56:B7:79:3F - Root CA
$ python manage.py edit_ca --ocsp-url=http://ocsp.example.com/ \
> 34:D6:02:B5:B8:27:4F:51:9A:16:0C:B8:56:B7:79:3F
Run an OCSP responser with openssl ocsp
¶
OpenSSL ships with the openssl ocsp
command that allows you to run an OCSP
responser, but note that the manpage says “only useful for test and
demonstration purposes”.
To use the command, generate an index:
$ python manage.py dump_ocsp_index ocsp.index
OpenSSL itself allows you to run an OCSP responder with this command:
$ openssl ocsp -index ocsp.index -port 8888 -rsigner ocsp.pem \
> -rkey ocsp.example.com.key -CA files/ca.crt -text