http://kamailio.org/docs/modules/stable/modules/tls.html
Assumptions ------------ The default openssl configuration (usually /etc/ssl/openssl.cnf) default_ca section is the one distributed with openssl and uses the default directories: ... default_ca = CA_default # The default ca section [ CA_default ] dir = ./demoCA # Where everything is kept certs = $dir/certs # Where the issued certs are kept crl_dir = $dir/crl # Where the issued crl are kept database = $dir/index.txt # database index file. #unique_subject = no # Set to 'no' to allow creation of # several ctificates with same subject. new_certs_dir = $dir/newcerts # default place for new certs. certificate = $dir/cacert.pem # The CA certificate serial = $dir/serial # The current serial number crlnumber = $dir/crlnumber # the current crl number crl = $dir/crl.pem # The current CRL private_key = $dir/private/cakey.pem# The private key RANDFILE = $dir/private/.rand # private random number file ... If this is not the case create a new openssl config file that uses the above paths for the default CA and add to all the openssl commands: -config filename. E.g.: openssl ca -config my_openssl.cnf -in ser1_cert_req.pem -out ser1_cert.pem Creating CA certificate ----------------------- 1. create CA dir mkdir ca cd ca 2. create ca dir structure and files (see ca(1)) mkdir demoCA #default CA name, edit /etc/ss/openssl.cnf mkdir demoCA/private mkdir demoCA/newcerts touch demoCA/index.txt echo 01 >demoCA/serial echo 01 >demoCA/crlnumber 2. create CA private key openssl genrsa -out demoCA/private/cakey.pem 2048 chmod 600 demoCA/private/cakey.pem 3. create CA self-signed certificate openssl req -out demoCA/cacert.pem -x509 -new -key demoCA/private/cakey.pem Creating a server/client certificate ------------------------------------ 1. create a certificate request (and its private key in privkey.pem) openssl req -out ser1_cert_req.pem -new -nodes WARNING: the organization name should be the same as in the ca certificate. 2. sign it with the ca certificate openssl ca -in ser1_cert_req.pem -out ser1_cert.pem 3. copy ser1_cert.pem to your ser config. dir Setting sip-router to use the certificate ----------------------------------------- 1. create the ca list file: for each of your ca certificates that you intend to use do: cat cacert.pem >>calist.pem 2. copy your sip-router certificate, private key and ca list file to your intended machine (preferably in your sip-router configuration directory, this is the default place sip-router searches for). 3. set up sip-router.cfg to use the certificate if your ser certificate name is different from cert.pem or it is not placed in sip-router cfg. directory, add to your sip-router.cfg: modparam("tls", "certificate", "/path/cert_file_name") 4. set up sip-router to use the private key if your private key is not contained in the same file as the certificate (or the certificate name is not the default cert.pem), add to your sip-router.cfg: modparam("tls", "private_key", "/path/private_key_file") 5. set up sip-router to use the ca list (optional) add to your sip-router.cfg: modparam("tls", "ca_list", "/path/ca_list_file") 6. set up tls authentication options: modparam("tls", "verify_certificate", 1) modparam("tls", "require_certificate", 1) (for more information see the module parameters documentation) Revoking a certificate and using a CRL -------------------------------------- 1. revoking a certificate: openssl ca -revoke bad_cert.pem 2. generate/update the certificate revocation list: openssl ca -gencrl -out my_crl.pem 3. copy my_crl.pem to your ser config. dir 4. set up sip-router to use the CRL: modparam("tls", "crl", "path/my_crl.pem")