CURLOPT_ISSUERCERT(3) Library Functions Manual CURLOPT_ISSUERCERT(3)
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
(C) has to be set too for the check to fail).
(Added in 7.19.0)
Using this option multiple times makes the last set string override the
previous ones. Set it to NULL to disable its use again.
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
curl_easy_setopt(3) returns a CURLcode indicating success or error.
CURLE_OK (0) means everything was OK, non-zero means an error occurred,
see libcurl-errors(3).
SEE ALSO
CURLOPT_CRLFILE(3), CURLOPT_SSL_VERIFYHOST(3),
CURLOPT_SSL_VERIFYPEER(3)
libcurl 2025-02-08 CURLOPT_ISSUERCERT(3)
curl 8.12.0 - Generated Sat Feb 15 11:37:36 CST 2025