plucky (3) CURLOPT_DOH_SSL_VERIFYPEER.3.gz

NAME

       CURLOPT_DOH_SSL_VERIFYPEER - verify the DoH SSL certificate

SYNOPSIS

       #include <curl/curl.h>

       CURLcode curl_easy_setopt(CURL *handle, CURLOPT_DOH_SSL_VERIFYPEER,
                                 long verify);

DESCRIPTION

       Pass a long as parameter set to 1L to enable or 0L to disable.

       This  option  tells  curl  to verify the authenticity of the DoH (DNS-over-HTTPS) server's certificate. A
       value of 1 means curl verifies; 0 (zero) means it does not.

       This option is the DoH equivalent of CURLOPT_SSL_VERIFYPEER(3) and  only  affects  requests  to  the  DoH
       server.

       When  negotiating  a  TLS or SSL connection, the server sends a certificate indicating its identity. curl
       verifies whether the certificate is authentic, i.e. that you  can  trust  that  the  server  is  who  the
       certificate  says  it  is.  This trust is based on a chain of digital signatures, rooted in certification
       authority (CA) certificates you supply. curl uses a default bundle of CA certificates (the path for  that
       is determined at build time) and you can specify alternate certificates with the CURLOPT_CAINFO(3) option
       or the CURLOPT_CAPATH(3) option.

       When CURLOPT_DOH_SSL_VERIFYPEER(3) is enabled, and the verification fails to prove that  the  certificate
       is  authentic,  the connection fails. When the option is zero, the peer certificate verification succeeds
       regardless.

       Authenticating the certificate is not enough to be sure about the server.  You  typically  also  want  to
       ensure  that  the  server  is the server you mean to be talking to. Use CURLOPT_DOH_SSL_VERIFYHOST(3) for
       that. The check that the hostname in the certificate is valid for the hostname you are connecting  to  is
       done independently of the CURLOPT_DOH_SSL_VERIFYPEER(3) option.

       WARNING: disabling verification of the certificate allows bad guys to man-in-the-middle the communication
       without you knowing it. Disabling verification makes the communication insecure. Just  having  encryption
       on a transfer is not enough as you cannot be sure that you are communicating with the correct end-point.

DEFAULT

       1

PROTOCOLS

       This functionality affects all TLS based protocols: HTTPS, FTPS, IMAPS, POP3S, SMTPS etc.

       All TLS backends support this option.

EXAMPLE

       int main(void)
       {
         CURL *curl = curl_easy_init();
         if(curl) {
           curl_easy_setopt(curl, CURLOPT_URL, "https://example.com");

           curl_easy_setopt(curl, CURLOPT_DOH_URL,
                            "https://cloudflare-dns.com/dns-query");

           /* Disable certificate verification of the DoH server */
           curl_easy_setopt(curl, CURLOPT_DOH_SSL_VERIFYPEER, 0L);

           curl_easy_perform(curl);
         }
       }

AVAILABILITY

       Added in curl 7.76.0

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_CAINFO(3),   CURLOPT_CAPATH(3),  CURLOPT_DOH_SSL_VERIFYHOST(3),  CURLOPT_PROXY_SSL_VERIFYHOST(3),
       CURLOPT_PROXY_SSL_VERIFYPEER(3), CURLOPT_SSL_VERIFYHOST(3), CURLOPT_SSL_VERIFYPEER(3)