CURL with SSL certificates fails: error 58 cannot install the private key file

Question

I am trying to connect to a remote host using cURL. Connection requires the use of a certificate and a secret key that is password protected. So far I have not been crowned with this code below:

<?php $wsdl = 'https://domain.com/?wsdl'; $certFile = getcwd() . '/auth/cert.pem'; $keyFile = getcwd() . '/auth/key.pem'; $password = 'pwd'; $ch = curl_init(); curl_setopt($ch, CURLOPT_URL, $wsdl); curl_setopt($ch, CURLOPT_SSLCERT, $certFile); curl_setopt($ch, CURLOPT_SSLKEYPASSWD, $password); curl_setopt($ch, CURLOPT_SSLKEY, $keyFile); #curl_setopt($ch, CURLOPT_FRESH_CONNECT, true); #curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false); #curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, false); $output = curl_exec($ch); var_dump(curl_errno($ch)); var_dump(curl_error($ch)); 

As a result, I get error 58 : unable to set private key file: '/home/.../domains/.../public_html/auth/key.pem' type PEM .

Things I've tried so far:

• Check if the key file is available as suggested here: Cannot use libcurl to access a site requiring client authentication . Trying to pass a file through openssl_private_key() gives me a resource, not a logical one. So it seems good.
• Switch the order of the contents in the key.pem file as suggested here: Cannot use libcurl to access a site that requires client authentication . So far no luck.
• Played with some other options, such as SLL_VERIFY_PEER , SSL_VERIFY_HOST , SSL_CERTTYPE and other options that seemed trivial in relation to official PHP documents. So far no luck.

I'm sure the problem lies in my configuration, but I'm not sure where to look.

Answer 1

I fixed this problem. I think because of the number of questions regarding this problem and the number of different solutions, others will benefit from the solution. Here:

I used the openssl CLI program to convert the .p12 key file to a .pem key file. The trick is how the transformation happens.

First, I converted it using this command, and I had a problem as described in the question:

openssl pkcs12 -in key.p12 -out key.pem -nodes -clcerts

While the command below did the trick:

openssl pkcs12 -in key.p12 -out key.pem -clcerts

For more information, see the source I used: https://community.qualys.com/docs/DOC-3273

Answer 2

Just in case, this is useful for others looking for this problem, I found that CURLOPT_SSLCERT and CURLOPT_SSLKEY do not work with relative paths.

This is with WAMP, php version 5.5 on Windows.