Ubuntu Manpage: CURLOPT_CAINFO - path to Certificate Authority (CA) bundle

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 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) 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  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.