Tribblix: manual page: CURLOPT_DOH_SSL

CURLOPT_DOH_SSL_VERIFYHOST(3) Introduction to Library Functions

NAME

CURLOPT_DOH_SSL_VERIFYHOST - verify the hostname in the DoH SSL
certificate

SYNOPSIS

#include <curl/curl.h>

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

DESCRIPTION

Pass a long set to 2L as asking curl to verify the DoH
(DNS-over-HTTPS) server's certificate name fields against the
hostname.

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

When CURLOPT_DOH_SSL_VERIFYHOST(3) is 2, the SSL certificate provided
by the DoH server must indicate that the server name is the same as
the server name to which you meant to connect to, or the connection
fails.

curl considers the DoH server the intended one when the Common Name
field or a Subject Alternate Name field in the certificate matches
the hostname in the DoH URL to which you told curl to connect.

When the verify value is set to 1L it is treated the same as 2L.
However for consistency with the other VERIFYHOST options we suggest
use 2 and not 1.

When the verify value is set to 0L, the connection succeeds
regardless of the names used in the certificate. Use that ability
with caution.

See also CURLOPT_DOH_SSL_VERIFYPEER(3) to verify the digital
signature of the DoH server certificate.

DEFAULT

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 host name verification of the DoH server */
curl_easy_setopt(curl, CURLOPT_DOH_SSL_VERIFYHOST, 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).