CURLOPT_PROXY_ISSUERCERT(3)                           Library Functions Manual

NAME
       CURLOPT_PROXY_ISSUERCERT - proxy issuer SSL certificate filename

SYNOPSIS
       #include <curl/curl.h>

       CURLcode curl_easy_setopt(CURL *handle, CURLOPT_PROXY_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 of the
       HTTPS proxy 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_PROXY_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_PROXY_SSL_VERIFYPEER(3) has to be set too for the check to
       fail).

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

DEFAULT
       NULL

PROTOCOLS
       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/");
           /* using an HTTPS proxy */
           curl_easy_setopt(curl, CURLOPT_PROXY, "https://localhost:443");
           curl_easy_setopt(curl, CURLOPT_PROXY_ISSUERCERT, "/etc/certs/cacert.pem");
           res = curl_easy_perform(curl);
           curl_easy_cleanup(curl);
         }
       }

AVAILABILITY
       Added in 7.71.0. This option is supported by the OpenSSL and GnuTLS
       backends.

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_ISSUERCERT(3), CURLOPT_PROXY_SSL_VERIFYHOST(3),
       CURLOPT_PROXY_SSL_VERIFYPEER(3), CURLOPT_SSL_VERIFYHOST(3),
       CURLOPT_SSL_VERIFYPEER(3)

libcurl                          April 26 2024     CURLOPT_PROXY_ISSUERCERT(3)