Can't connect to HTTPS site using cURL. Returns 0 length content instead. What can I do?

Question

I have a site that connects using cURL (latest version) to a secure gateway for payment.

The problem is cURL always returns 0 length content. I get headers only. And only when I set cURL to return headers. I have the following flags in place.

curl_setopt($ch, CURLOPT_HTTPAUTH, CURLAUTH_ANY);
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, false);
curl_setopt($ch, CURLOPT_URL, $gatewayURI);
curl_setopt($ch, CURLOPT_HEADER, 1);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt ($ch, CURLOPT_POST, 1);

The header returned is

HTTP/1.1 100 Continue

HTTP/1.1 200 OK
Date: Tue, 25 Nov 2008 01:08:34 GMT
Server: Microsoft-IIS/6.0
X-Powered-By: ASP.NET
Content-Length: 0
Content-Type: text/html
Set-Cookie: ASPSESSIONIDxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx; path=/
Cache-control: private

I have also tried cURL'ing different sites and they return content fine. I think the problem might have something to do with the https connection.

I have spoken with the company and they are unhelpful.

Has anyone else experienced this error and know a work around? Should I ditch cURL and try and use fsockopen() ?

Thank you. :)

Answer 1

I had the same problem today. Curl comes with an outdated file to authenticate HTTPS certificates from.

get the new one from:

http://curl.haxx.se/ca/cacert.pem

save it into some dir on your site

and add

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

To every request :-)

IGNORE any dumbass comments about disabling CURLOPT_VERIFYPEER and CURLOPT_VERIFYHOST!! That leaves your code vulnerable to man in the middle attacks!

December 2016 edit:

Solve this properly by using Jasen's method mentioned below.

add curl.cainfo=/etc/ssl/certs/ca-certificates.crt to you php.ini

October 2017 edit:

There is now a composer package that helps you manage the ca certificates, so that you're not vulnerable if your cacert.pem becomes outdated due to revoking certificates.

https://github.com/paragonie/certainty -> composer require paragonie/certainty:dev-master