openssl_pkey_new() throwing errors -- Proper openssl.cnf setup for php

I tried this on my Mac and a fresh install of CentOS 6.3 and I'm getting the same error. I get my CentOS packages from IUS. It's weird though because even though I'm getting this message, the key is actually being generated.

The following code:

$res = openssl_pkey_new();
openssl_pkey_export($res, $privkey);
var_dump(openssl_error_string());
var_dump($privkey);

Gives me the following output:

string(68) "error:0E06D06C:configuration file routines:NCONF_get_string:no value"
string(887) "-----BEGIN RSA PRIVATE KEY-----
MIICXQIBAAKBgQDdh4FiOEtUZzvTSnlb/pJHjmsS9rOHQ7PU2WOO6ZHxYRIgK1NR
ReY7bBwEsT2ziUpx0b8K2Fx4m+XovzysB/lVrKbrdbHoVtGuJGZjYSXgFlCRTBu+
+TnAPUBF0LGJfxfVzjOkHzsh02lH3fvzFpFgRZRWs4za+vVzIweeOweYTwIDAQAB
AoGANZD5iS2BkZQw1COS+tqwtlrKq1g6CwAk8NfsCfeSkaJeRqcTS3iydjXrBHtz
JwGQnbsRDedJXOSdkE0Ft7dp44lijOAp1ngMDCKbabxVN2Go6b1d743HE0oIhFCC
Dv2B9kf9vzeYy+0/BVCs5i4iPoKXJJTSJrWoDxrFEJWSJIkCQQDwe39bOFHmQlxz
pbfT3DZ8Q311xFo6PewcAf7DTsikoPZANx0GQ41WdZj6/n4QVP4k+TnhZLiJzsH+
p3RUrx8tAkEA69LsgPrQMZ0YjsE2vjRLdJmp1916G1xqSLIVWDUPd9Ns+MA8YKTx
AQxC3dl3n+w24m7UlCThANlU/+2r0eoi6wJBAKIxGOdEJ/Cdp08UYNRR/Kl4t2A7
SwNnChylt9awByEJsqwCv9+epe+/Jqt6AzouqK31LXV4AgJn4W1IMWyAJA0CQCp0
6/2AqnD0PpKc+JUf5yHT9H8Xsb8xUTVLUopx6xoAp5LVUUl5CKbOpU85ss7JAUyc
9YrCZPv5JNN6379ILwcCQQDDcjtNnhQHukQQQ8iVL9YCrWzyCgplTz3uktueT+Dd
SDK1bCM4xDehfG3RKu1ZNx80Q0nzmi7FSPJ2md7qSIHc
-----END RSA PRIVATE KEY-----
"

I suspect it being a bug in PHP. Some sort of openssl configuration PHP is getting hung up on. I found a bug report about this on php.net, but it "started working" for the user so the bug was closed.

As an alternative, you can check out phpseclib, a library purely written in PHP.

When using openssl_csr_new make sure the first parameter $dn does not contain keys with empty values.

For example, this call to openssl_csr_new would trigger the error

0E06D06C:configuration file routines:NCONF_get_string:no value

<?php

$dn = [
    'CN' => 'example.com',
    'ST' => '',
    'C'  => '',
    'O'  => '',
];

openssl_csr_new($dn, $privKey);