OpenID-eID

2008-09-19T12:28:23Z

Karel: the opensc package is needed for pkcs15-tool

Here are my attempts to create an [[OpenID]] provider based on the [[Belgian eID]]

===Install packages===
Let's get apache2, php5 and openssl stuff:
apt-get install apache2-utils apache2-mpm-prefork libapache2-mod-php5 php5 openssl ssl-cert opensc

===Setup apache server with SSL===
Create self-signed certificate
make-ssl-cert /usr/share/ssl-cert/ssleay.cnf /etc/apache2/ssl/apache.pem
Little problem: by default the certificate is valid only 30 days, you've to edit make-ssl-cert script and add "-days" options, e.g:
openssl req -days 1024 ...
Verify generated certificate
openssl x509 -text -in /etc/apache2/ssl/apache.pem
Start from ssl example config
zcat /usr/share/doc/apache2.2-common/examples/apache2/extra/httpd-ssl.conf.gz \
> /etc/apache2/sites-available/default-ssl
Activates ssl module
a2enmod ssl
Activates ssl virtualhost
a2ensite default-ssl
Edit /etc/apache2/sites-available/default-ssl
SSLCertificateFile /etc/apache2/ssl/apache.pem
#SSLCertificateKeyFile not required as apache.pem contains also the key
And the usual stuff
DocumentRoot "/var/www"
ServerName ...
ServerAdmin ...
ErrorLog /var/log/apache2/error.log
TransferLog /var/log/apache2/access.log
To activate only the secure ciphers:
SSLCipherSuite HIGH:MEDIUM:!ADH
SSLProtocol -ALL +SSLv3 +TLSv1

===Adding Belgian Government Root certificates===
You can extract the Belgium Root CA and the Citizen CA from your eID:
pkcs15-tool --read-certificate 04 > /etc/apache2/ssl/ca/belgium.crt
pkcs15-tool --read-certificate 06 >> /etc/apache2/ssl/ca/belgium.crt
Then add client certificate requirements to /etc/apache2/sites-available/default-ssl
SSLCACertificateFile /etc/apache2/ssl/ca/belgium.crt
SSLOptions +StrictRequire
SSLVerifyClient require
SSLVerifyDepth 10
<Location />
# accept only certificates emitted by Citizen CA:
SSLRequire %{SSL_CLIENT_I_DN_C} eq "BE" \
and %{SSL_CLIENT_I_DN_CN} in {"Citizen CA"}
</Location>
According to the doc, because of a bug in Internet Explorer, you also need to add GlobalSign Root certificate...
===Retrieving citizens' certificate information===
The user's distinguish name can be retrieved from php with
$_SERVER['SSL_CLIENT_S_DN']
And the user's name with
$_SERVER['SSL_CLIENT_S_DN_CN']

===TODO: cf [http://www.belgium.be/zip/eid_authentication_proxy_fr.html apache SSL reverse proxy] proposed by the government===
* [http://issues.apache.org/bugzilla/show_bug.cgi?id=41123 OCSP support for mod_ssl]
Add to /etc/apache2/sites-available/default-ssl:
SSLUseOCSP on
SSLForceValidation on
* [http://issues.apache.org/bugzilla/show_bug.cgi?id=35083 Certificate validation problems trapping]
Enable ssl_error_module:
LoadModule ssl_error_module modules/mod_ssl_error.so
And add to /etc/apache2/sites-available/default-ssl:
<IfModule mod_ssl_error.c>
SSL_Error_DefaultURL "/error/invalid.html"
SSL_Error_URL 23 "/error/revoked.html"
SSL_Error_URL 10 "/error/expired.html"
</IfModule>
cf doc...
* Or simply make the client certificate as optional and test for it in php

===Hacking [http://siege.org/projects/phpMyID/ phpMyID]===

Details on the patch
* remove HTTP Digest for the authorization step
* redirect authorization to HTTPS as we'll deal with SSL client certificates
* TODO
* [http://id.yobi.be/MyID.phps current source code of the hacked phpMyID]

Status:
* I could validate the client certificate against the root CA and I could extract the data of the certificate
* I could create various OpenIDs based on the certificate data<br>Everything is extracted only from the names and RRN, not on the serial nr of the certificate or any part prone to be changed if you've to renew your ID card! (unless they change the way they write your name on the certificate...)
* I still consider RRN as sensitive data so the IDs I can provide must be a balance between several factors:
** friendliness (easy to remember)
** displaying your name or not?
** avoid clashes
** RRN retrieval more or less robust against brute force retrieval
* So '''about security & clashes''', the hash is very very safe, the others, well, it depends how likely is your name...
* I added a discover mode which tells you what are your OpenIDs given your own eID, you can try here:
http://id.yobi.be/?openid.mode=discover
# This will return in my case:
http://id.yobi.be/?id=ae96fba0cd9515cd
http://id.yobi.be/?id=philippe.teuwen.159
http://id.yobi.be/?id=philippe.yvon.teuwen
Another kind of ID could be
id=firstname.lastname.Hash(RRN|firstname2|initial3|firstname|lastname)
So it tells your name but still hides RRN is a moderately hard to brute-force hash as you've to guess RRN but also your second firstname & initial of the third firstname (if you've a single firstname you're out of luck, I've 5 firstnames!)

Estonian [https://openid.ee/about/english counterpart] plans to provide simply firstname.lastname and to build an index in case of clashes.<br>
But this requires to have a stateful server and I don't want that, I want anybody to build his own service and the generated OpenIDs will always be the same, only depending on the certificate data, not on "who came first".<br>Otherwise imagine the mess if the server data gets destroyed!
* My OpenIDs are now valid and successfully tested with e.g. [http://www.openidenabled.com/resources/openid-test/checkup/start?openid_url=http%3A%2F%2Fid.yobi.be%2F%3Fid%3Dae96fba0cd9515cd this OpenID checking server]

Todo:
* CRL & cf TODO patches above
* Maybe some stateful stuff on the server for minor info: pavatar, microid...
* Check if server is able to do stateful associations
* Support also for CAcert client certificates, be our own CA?
* Clean-up server and delegate URLs
** e.g. http://id.yobi.be & http://id.yobi.be/ae96fba0cd9515cd (or xri?)
* Move to php-openid
Security:
* If someone knows your name and your partial hash he can bruteforce your RRN (and your middle name if the attacker didn't get it) but is RRN a secret anymore? Given any email you signed with your eID is enough to simply extract (and not bruteforce) your RRN...

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