NAME

       CURLOPT_CAINFO - path to Certificate Authority (CA) bundle

SYNOPSIS

       #include <curl/curl.h>

       CURLcode curl_easy_setopt(CURL *handle, CURLOPT_CAINFO, char *path);

DESCRIPTION

       Pass  a  char * to a zero terminated string naming a file holding one or more certificates
       to verify the peer with.

       If CURLOPT_SSL_VERIFYPEER(3) is zero and you avoid  verifying  the  server's  certificate,
       CURLOPT_CAINFO(3) need not even indicate an accessible file.

       This  option is by default set to the system path where libcurl's cacert bundle is assumed
       to be stored, as established at build time.

       If curl is built against the NSS SSL library, the NSS PEM  PKCS#11  module  (libnsspem.so)
       needs  to  be  available  for this option to work properly.  Starting with curl-7.55.0, if
       both CURLOPT_CAINFO(3) and CURLOPT_CAPATH(3) are unset, NSS-linked libcurl tries  to  load
       libnssckbi.so, which contains a more comprehensive set of trust information than supported
       by nss-pem, because libnssckbi.so also includes information about distrusted certificates.

       (iOS and macOS only) If curl is built  against  Secure  Transport,  then  this  option  is
       supported  for backward compatibility with other SSL engines, but it should not be set. If
       the option is not set, then curl will use the certificates in the system and user Keychain
       to  verify  the  peer,  which  is the preferred method of verifying the peer's certificate
       chain.

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

DEFAULT

       Built-in system specific

PROTOCOLS

       All TLS based protocols: HTTPS, FTPS, IMAPS, POP3S, SMTPS etc.

EXAMPLE

       CURL *curl = curl_easy_init();
       if(curl) {
         curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/");
         curl_easy_setopt(curl, CURLOPT_CAINFO, "/etc/certs/cabundle.pem");
         ret = curl_easy_perform(curl);
         curl_easy_cleanup(curl);
       }

AVAILABILITY

       For SSL engines that don't support certificate files the CURLOPT_CAINFO option is ignored.
       Refer to https://curl.haxx.se/docs/ssl-compared.html

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_CAPATH(3), CURLOPT_SSL_VERIFYPEER(3), CURLOPT_SSL_VERIFYHOST(3),