- Introducing CURLOPT_CERTINFO and the corresponding CURLINFO_CERTINFO. By

enabling this feature with CURLOPT_CERTINFO for a request using SSL (HTTPS
  or FTPS), libcurl will gather lots of server certificate info and that info
  can then get extracted by a client after the request has completed with
  curl_easy_getinfo()'s CURLINFO_CERTINFO option. Linus Nielsen Feltzing
  helped me test and smoothen out this feature.

  Unfortunately, this feature currently only works with libcurl built to use
  OpenSSL.

  This feature was sponsored by networking4all.com - thanks!

lib/getinfo.c

@@ -217,6 +217,11 @@ CURLcode Curl_getinfo(struct SessionHandle *data, CURLINFO info, ...)
     /* Return the ip address of the most recent (primary) connection */
     *param_charp = data->info.ip;
     break;
+  case CURLINFO_CERTINFO:
+    /* Return the a pointer to the certinfo struct. Not really an slist
+       pointer but we can pretend it is here */
+    *param_slistp = (struct curl_slist *)&data->info.certs;
+    break;
   default:
     return CURLE_BAD_FUNCTION_ARGUMENT;
   }