NAME

       CURLOPT_ISSUERCERT - issuer SSL certificate filename

SYNOPSIS

       #include <curl/curl.h>

       CURLcode curl_easy_setopt(CURL *handle, CURLOPT_ISSUERCERT, char *file);

DESCRIPTION

       Pass  a char pointer to a null-terminated string naming a file holding a CA certificate in
       PEM format. If the option is set, an additional check  against  the  peer  certificate  is
       performed  to verify the issuer is indeed the one associated with the certificate provided
       by the option. This additional check is useful in  multi-level  PKI  where  one  needs  to
       enforce that the peer certificate is from a specific branch of the tree.

       This  option  makes sense only when used in combination with the CURLOPT_SSL_VERIFYPEER(3)
       option. Otherwise, the result of the check is not considered as failure.

       A specific error code (CURLE_SSL_ISSUER_ERROR)  is  defined  with  the  option,  which  is
       returned  if the setup of the SSL/TLS session has failed due to a mismatch with the issuer
       of peer certificate (CURLOPT_SSL_VERIFYPEER(3) has to be set too for the check  to  fail).
       (Added in 7.19.0)

       The application does not have to keep the string around after setting this option.

DEFAULT

       NULL

PROTOCOLS

       This functionality affects all TLS based protocols: HTTPS, FTPS, IMAPS, POP3S, SMTPS etc.

       This option works only with the following TLS backends: GnuTLS and OpenSSL

EXAMPLE

       int main(void)
       {
         CURL *curl = curl_easy_init();
         if(curl) {
           CURLcode res;
           curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/");
           curl_easy_setopt(curl, CURLOPT_ISSUERCERT, "/etc/certs/cacert.pem");
           res = curl_easy_perform(curl);
           curl_easy_cleanup(curl);
         }
       }

AVAILABILITY

       Added in curl 7.19.0

RETURN VALUE

       Returns   CURLE_OK   if   the   option  is  supported,  CURLE_UNKNOWN_OPTION  if  not,  or
       CURLE_OUT_OF_MEMORY if there was insufficient heap space.

SEE ALSO

       CURLOPT_CRLFILE(3), CURLOPT_SSL_VERIFYHOST(3), CURLOPT_SSL_VERIFYPEER(3)