Winter 2010 Posters/Certs

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Project Name

Koji Certification Creation


Sadiki Latty

Understanding the Koji Process

Before understanding the koji certification process, one must first understand the koji process. Koji utilizes various machines (virtual or physical) to build software packages for different architectures. We decided to create a koji builder scenario for our ARM based physical machines (openrd, sheeva plug) and our virtual machine (arm emulators). In order for these machines to perform these tasks we need a central monitoring system that can track progress accordingly, this is the kojihub. Before these builders can communicate with the hub they need to be authenticated and verified as authorized builders, and that is where koji certifications come in.

Koji Cert Components

Koji certs allow a koji builder to communicate with the koji hub. The various necessary components are as follows.

  • Koji Certificate Authority

  • Koji Server Cert

  • Koji Builder Cert

Together, these certs allow the builders to communicate with the koji hub and visa versa. After researching and a bit of tweaking, I managed to utilize a concept from Fedora Projects website ( and created a script which would make minimal effort for anyone making multiple certs, or for anyone who would rather quickly make a cert than learn the process.

In our scenario, we used SSL to perform our configuration, however, Kerboros has another means of accomplishing the same thing without requiring authentication. This path however is only a 'quick-fix' because eventually SSL will have to be used.

Koji Cert Process

  1. A certificate authority must be created.
  2. The certificate authority must have a private key and public key created
  3. A certificate must be created for the server using the configuration and signature of the ca
  4. Other clients can then be created such as the kojihub, kojiweb etc

How to use the script

I managed to break the code down into 2 separate pieces. One for making the CA (Certificate Authority) and one for making the certs for the different users/builders you would like configured. The way my script differs from the original is that it uses the variables passed to it as the default commonName in the ssl.cnf file.

For example, when executing my script to create a cert for a new user...lets say "kojiuser1":

./certscript kojiuser1

The script as usual asks the various questions about where you are from and the OU name and the province etc, etc, but is then followed by the question of what the commonName should be. This name and/or the OU name should always be different from any other certs already created or you will get a TXT_ error. My script makes pressing enter easier by allowing you to press enter knowing that the commonName will be (by default).. "kojiuser1". Now this may not seem like anything huge for the creation of one user but what if we were creating multiple users (which was the case with me).

for user in arm{1..25}


>./certscript $user


In addition, a folder called "confs" holds all the conf files used to make the certs, this makes backtracking easier. For now only one line gets modified but it leaves progression for future endeavours. The only time you need to press a key other than enter is when it asks if you want to sign the cert. Of course 95% of the script remains the same as before but this modification makes life one step easier and hence minimizes the length of the cert creation process.


Here is an example of a tweaked ssl.cnf file:

OME = .

RANDFILE = .rand


default_ca = ca_default


dir = .

certs = $dir/certs

crl_dir = $dir/crl

database = $dir/index.txt

new_certs_dir = $dir/newcerts

certificate = $dir/%s_ca_cert.pem

private_key = $dir/private/%s_ca_key.pem

serial = $dir/serial

crl = $dir/crl.pem

x509_extensions = usr_cert

name_opt = ca_default

cert_opt = ca_default

default_days = 3650

default_crl_days = 30

default_md = md5

preserve = no

policy = policy_match

[policy_match] countryName = match

stateOrProvinceName = match

organizationName = match

organizationalUnitName = optional

commonName = supplied

emailAddress = optional

[req] default_bits = 1024

default_keyfile = privkey.pem

distinguished_name = req_distinguished_name

attributes = req_attributes

x509_extensions = v3_ca # The extentions to add to the self signed cert

string_mask = MASK:0x2002


countryName = Country Name (2 letter code)

countryName_default = CA

countryName_min = 2

countryName_max = 2

stateOrProvinceName = State or Province Name (full name)

stateOrProvinceName_default = Ontario

localityName = Locality Name (eg, city)

localityName_default = Toronto

0.organizationName = Organization Name (eg, company)

0.organizationName_default = Seneca CDOT

organizationalUnitName = Organizational Unit Name (eg, section)

commonName = Common Name (eg, your name or your server\'s hostname)

commonName_default = hongkong

commonName_max = 64

emailAddress = Email Address

emailAddress_max = 64


challengePassword = A challenge password

challengePassword_min = 4

challengePassword_max = 20

unstructuredName = An optional company name


basicConstraints = CA:FALSE

nsComment = "OpenSSL Generated Certificate"

subjectKeyIdentifier = hash

authorityKeyIdentifier = keyid,issuer:always


subjectKeyIdentifier = hash

authorityKeyIdentifier = keyid:always,issuer:always

basicConstraints = CA:true

Problems Encountered

Because the koji certificate is one of the first things that have to be established before anything else will work (the other being the database), it is typically the first one to get picked on when something isnt working. One problem during this process was the creation of kojihub, and kojiweb. These 2 certs are have a small stipulation that states that their 'commonName' should be the same. Unknown to me at the time, a prerequisite of this requires that the OU (Organizational Unit) should be different or else the cert will complain during creation that another cert with identical settings has been created. After some more research on the Fedora Project website, I found the necessary steps to rectify the issue and move on.

Another issue I came across was the fact that different sources provided different "requirements". For example, some sources stated that when creating the kojihub and kojiweb certs that the "Common Name" value is required to be a FQDN (Fully Qualified Domain Name) while others said it didnt. This made troubleshooting the kojihub process rather strenuous.





  • Fedora
  • Seneca
  • Apache
  • OpenSSL


My Blog:

Fedora Projects Koji Setup Document: