CURLOPT_DOH_SSL_VERIFYPEER(3) Library Functions Manual
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
Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION
if not.
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)
libcurl 2024-08-05 CURLOPT_DOH_SSL_VERIFYPEER(3)
curl 8.9.1 - Generated Tue Aug 6 15:30:13 CDT 2024