mirror of
https://github.com/curl/curl.git
synced 2026-05-04 19:39:57 +03:00
118 lines
3.4 KiB
Markdown
118 lines
3.4 KiB
Markdown
---
|
|
c: Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
|
|
SPDX-License-Identifier: curl
|
|
Title: CURLOPT_SSL_VERIFYHOST
|
|
Section: 3
|
|
Source: libcurl
|
|
See-also:
|
|
- CURLOPT_CAINFO (3)
|
|
- CURLOPT_PINNEDPUBLICKEY (3)
|
|
- CURLOPT_SSL_VERIFYPEER (3)
|
|
- CURLOPT_PROXY_SSL_VERIFYHOST (3)
|
|
- CURLOPT_DOH_SSL_VERIFYHOST (3)
|
|
Protocol:
|
|
- TLS
|
|
TLS-backend:
|
|
- All
|
|
Added-in: 7.8.1
|
|
---
|
|
|
|
# NAME
|
|
|
|
CURLOPT_SSL_VERIFYHOST - verify the certificate's name against host
|
|
|
|
# SYNOPSIS
|
|
|
|
~~~c
|
|
#include <curl/curl.h>
|
|
|
|
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_SSL_VERIFYHOST, long verify);
|
|
~~~
|
|
|
|
# DESCRIPTION
|
|
|
|
Pass a long set to 2L to make libcurl verify the host in the server's TLS
|
|
certificate.
|
|
|
|
When negotiating a TLS connection, the server sends a certificate indicating
|
|
its identity.
|
|
|
|
When CURLOPT_SSL_VERIFYHOST(3) is set to 1 or 2, the server certificate must
|
|
indicate that it was made for the hostname or address curl connects to, or the
|
|
connection fails. Simply put, it means it has to have the same name in the
|
|
certificate as is used 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 hostname in the
|
|
URL to which you told curl to connect.
|
|
|
|
When the *verify* value is 0, the connection succeeds regardless of the names
|
|
in the certificate. Use that ability with caution,
|
|
|
|
This option controls checking the server's certificate's claimed identity. The
|
|
separate CURLOPT_SSL_VERIFYPEER(3) options enables/disables verification that
|
|
the certificate is signed by a trusted Certificate Authority.
|
|
|
|
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.
|
|
|
|
When libcurl uses secure protocols it trusts responses and allows for example
|
|
HSTS and Alt-Svc information to be stored and used subsequently. Disabling
|
|
certificate verification can make libcurl trust and use such information from
|
|
malicious servers.
|
|
|
|
# MATCHING
|
|
|
|
A certificate can have the name as a wildcard. The only asterisk (`*`) must
|
|
then be the left-most character and it must be followed by a period. The
|
|
wildcard must further contain more than one period as it cannot be set for a
|
|
top-level domain.
|
|
|
|
A certificate can be set for a numerical IP address (IPv4 or IPv6), but then
|
|
it should be a Subject Alternate Name kind and its type should correctly
|
|
identify the field as an IP address.
|
|
|
|
# DEFAULT
|
|
|
|
2
|
|
|
|
# %PROTOCOLS%
|
|
|
|
# EXAMPLE
|
|
|
|
~~~c
|
|
int main(void)
|
|
{
|
|
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%
|
|
|
|
# HISTORY
|
|
|
|
In 7.28.0 and earlier: the value 1 was treated as a debug option of some
|
|
sorts, not supported anymore due to frequently leading to programmer mistakes.
|
|
|
|
From 7.28.1 to 7.65.3: setting it to 1 made curl_easy_setopt(3) return
|
|
an error and leaving the flag untouched.
|
|
|
|
From 7.66.0: libcurl treats 1 and 2 to this option the same.
|
|
|
|
# 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).
|