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 null-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 CA certificate 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) When curl uses Secure Transport this option is supported. If the option is
       not set, then curl will use the certificates in the system and user Keychain to verify the
       peer.

       (Schannel) This option is supported for Schannel in Windows 7 or later  but  we  recommend
       not  using  it  until Windows 8 since it works better starting then.  If the option is not
       set, then curl will use the certificates in the Windows' store of root  certificates  (the
       default for Schannel).

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

       The default value for this can be figured out with CURLINFO_CAINFO(3).

DEFAULT

       Built-in  system  specific.  When  curl  is  built with Secure Transport or Schannel, this
       option is not set by default.

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 the SSL engines that do not support certificate files the CURLOPT_CAINFO(3) option  is
       ignored. Schannel support added in libcurl 7.60.

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_CAINFO_BLOB(3),           CURLOPT_CAPATH(3),            CURLOPT_SSL_VERIFYPEER(3),
       CURLOPT_SSL_VERIFYHOST(3), CURLINFO_CAINFO(3), CURLOPT_CA_CACHE_TIMEOUT(3),