POST request with a self-signed certificate

Question

I'm going to POST some data from site A to site B using PHP. Site A has a commercial SSL certificate. Site B is going to have a self-signed certificate. Is this doable? If not, are there any configuration options in PHP (or Apache) that I can set to bypass the restrictions?

Answer 1

Presumably you'll be using curl on server A? There's a couple options in curl to disable certificate validation, which'll allow self-signed certs through. The link will still be encrypted, but you won't be able to trust that server B really IS server B:

curlopt_ssl_verifypeer  (checking the CA auth chain)
curlopt_ssl_verifyhost  (hostname/certname match checks)

Example PHP code:

$ch = curl_init("https://example.com/example/path"); 
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, false);
$response = curl_exec($ch);

Answer 2

Answers suggesting to disable CURLOPT_SSL_VERIFYPEER should not be accepted. The question is "Why doesn't it work with cURL", and as correctly pointed out it is dangerous. Disabling certificate checks opens the door for man in the middle attacks, which comes close to using just plain text http.

The error is probably caused by not having an up-to-date bundle of CA root certificates. This is typically a text file with a bunch of cryptographic signatures that curl uses to verify a host’s SSL certificate.

You need to make sure that your installation of PHP has one of these files, and that it’s up to date (otherwise download one here: http://curl.haxx.se/docs/caextract.html).

Then set in php.ini:

curl.cainfo = <absolute_path_to> cacert.pem

If you are setting it at runtime, use:

curl_setopt ($ch, CURLOPT_CAINFO, dirname(__FILE__)."/cacert.pem");

Answer copied from https://stackoverflow.com/a/23585500/2650835 for security reasons.