************************************************************************** * _ _ ____ _ * Project ___| | | | _ \| | * / __| | | | |_) | | * | (__| |_| | _ <| |___ * \___|\___/|_| \_\_____| * * Copyright (C) 1998 - 2015, Daniel Stenberg, <daniel (at] haxx.se>, et al. * * This software is licensed as described in the file COPYING, which * you should have received as part of this distribution. The terms * are also available at https://curl.haxx.se/docs/copyright.html. * * You may opt to use, copy, modify, merge, publish, distribute and/or sell * copies of the Software, and permit persons to whom the Software is * furnished to do so, under the terms of the COPYING file. * * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY * KIND, either express or implied. * ************************************************************************** CURLOPT_SSL_VERIFYHOST 3 "February 02, 2017" "libcurl 7.58.0" "curl_easy_setopt options"
NAME
CURLOPT_SSL_VERIFYHOST - verify the certificate's name against host
SYNOPSIS
#include <
curl/
curl.h>
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_SSL_VERIFYHOST, long verify);
DESCRIPTION
Pass a long as parameter specifying what to
verify.
This option determines whether libcurl verifies that the server cert is for
the server it is known as.
When negotiating TLS and SSL connections, the server sends a certificate
indicating its identity.
When
CURLOPT_SSL_VERIFYHOST(3) is 2, that certificate must indicate that
the server is the server to which you meant to connect, or the connection
fails. Simply put, it means it has to have the same name in the certificate as
is in the URL you operate against.
Curl considers the server the intended one when the Common Name field or a
Subject Alternate Name field in the certificate matches the host name in the
URL to which you told Curl to connect.
When the
verify value is 1,
curl_easy_setopt will return an error
and the option value will not be changed. It was previously (in 7.28.0 and
earlier) a debug option of some sorts, but it is no longer supported due to
frequently leading to programmer mistakes. Future versions will stop returning
an error for 1 and just treat 1 and 2 the same.
When the
verify value is 0, the connection succeeds regardless of the
names in the certificate. Use that ability with caution!
The default value for this option is 2.
This option controls checking the server's certificate's claimed identity.
The server could be lying. To control lying, see
CURLOPT_SSL_VERIFYPEER(3).
LIMITATIONS
DarwinSSL: If
verify value is 0, then SNI is also disabled. SNI is a TLS
extension that sends the hostname to the server. The server may use that
information to do such things as sending back a specific certificate for the
hostname, or forwarding the request to a specific origin server. Some hostnames
may be inaccessible if SNI is not sent.
NSS: If
CURLOPT_SSL_VERIFYPEER(3) is zero,
CURLOPT_SSL_VERIFYHOST(3) is also set to zero and cannot be overridden.
DEFAULT
2
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");
/* Set the default value: strict name check please */
curl_easy_setopt(curl, CURLOPT_SSL_VERIFYHOST, 2L);
curl_easy_perform(curl);
}
AVAILABILITY
If built TLS enabled.
RETURN VALUE
Returns CURLE_OK if TLS is supported, and CURLE_UNKNOWN_OPTION if not.
If 1 is set as argument,
CURLE_BAD_FUNCTION_ARGUMENT is returned.
"SEE ALSO"
CURLOPT_SSL_VERIFYPEER "(3), " CURLOPT_CAINFO "(3), "