NAME

       CURLINFO_CERTINFO - get the TLS certificate chain

SYNOPSIS

       #include <curl/curl.h>

       CURLcode curl_easy_getinfo(CURL *handle, CURLINFO_CERTINFO,
                                  struct curl_certinfo **chainp);

DESCRIPTION

       Pass  a  pointer to a struct curl_certinfo * and it is set to point to a struct that holds info about the
       server's certificate chain, assuming you had CURLOPT_CERTINFO(3) enabled when the request was made.

       struct curl_certinfo {
         int num_of_certs;
         struct curl_slist **certinfo;
       };

       The certinfo struct member is an array of linked  lists  of  certificate  information.  The  num_of_certs
       struct  member  is  the  number  of  certificates  which  is  the  number  of elements in the array. Each
       certificate's list has items with textual information in the format "name:content" such as "Subject:Foo",
       "Issuer:Bar", etc. The items in each list varies depending on the SSL backend and the certificate.

PROTOCOLS

       All TLS-based

EXAMPLE

       int main(void)
       {
         CURL *curl = curl_easy_init();
         if(curl) {
           CURLcode res;
           curl_easy_setopt(curl, CURLOPT_URL, "https://www.example.com/");

           /* connect to any HTTPS site, trusted or not */
           curl_easy_setopt(curl, CURLOPT_SSL_VERIFYPEER, 0L);
           curl_easy_setopt(curl, CURLOPT_SSL_VERIFYHOST, 0L);

           curl_easy_setopt(curl, CURLOPT_CERTINFO, 1L);

           res = curl_easy_perform(curl);

           if(!res) {
             int i;
             struct curl_certinfo *ci;
             res = curl_easy_getinfo(curl, CURLINFO_CERTINFO, &ci);

             if(!res) {
               printf("%d certs!\n", ci->num_of_certs);

               for(i = 0; i < ci->num_of_certs; i++) {
                 struct curl_slist *slist;

                 for(slist = ci->certinfo[i]; slist; slist = slist->next)
                   printf("%s\n", slist->data);
               }
             }
           }
           curl_easy_cleanup(curl);
         }
       }

       See also the certinfo.c example.

AVAILABILITY

       This option is only working in libcurl built with OpenSSL, GnuTLS, Schannel or Secure  Transport.  GnuTLS
       support added in 7.42.0. Schannel support added in 7.50.0. Secure Transport support added in 7.79.0.

       Added in 7.19.1

RETURN VALUE

       Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION if not.

SEE ALSO

       curl_easy_getinfo(3), curl_easy_setopt(3), CURLINFO_CAPATH(3)

libcurl 8.5.0                                   December 04, 2023                           CURLINFO_CERTINFO(3)