121 lines
4.3 KiB
Groff
121 lines
4.3 KiB
Groff
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.\" **************************************************************************
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.\" * _ _ ____ _
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.\" * Project ___| | | | _ \| |
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.\" * / __| | | | |_) | |
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.\" * | (__| |_| | _ <| |___
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.\" * \___|\___/|_| \_\_____|
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.\" *
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.\" * Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
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.\" *
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.\" * This software is licensed as described in the file COPYING, which
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.\" * you should have received as part of this distribution. The terms
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.\" * are also available at https://curl.se/docs/copyright.html.
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.\" *
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.\" * You may opt to use, copy, modify, merge, publish, distribute and/or sell
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.\" * copies of the Software, and permit persons to whom the Software is
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.\" * furnished to do so, under the terms of the COPYING file.
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.\" *
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.\" * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
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.\" * KIND, either express or implied.
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.\" *
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.\" * SPDX-License-Identifier: curl
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.\" *
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.\" **************************************************************************
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.\"
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.TH CURLOPT_SSLVERSION 3 "August 22, 2023" "ibcurl 8.3.0" libcurl
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.SH NAME
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CURLOPT_SSLVERSION \- preferred TLS/SSL version
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.SH SYNOPSIS
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.nf
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#include <curl/curl.h>
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CURLcode curl_easy_setopt(CURL *handle, CURLOPT_SSLVERSION, long version);
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.fi
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.SH DESCRIPTION
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Pass a long as parameter to control which version range of SSL/TLS versions to
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use.
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The SSL and TLS versions have typically developed from the most insecure
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version to be more and more secure in this order through history: SSL v2,
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SSLv3, TLS v1.0, TLS v1.1, TLS v1.2 and the most recent TLS v1.3.
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Use one of the available defines for this purpose. The available options are:
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.RS
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.IP CURL_SSLVERSION_DEFAULT
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The default acceptable version range. The minimum acceptable version is by
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default TLS v1.0 since 7.39.0 (unless the TLS library has a stricter rule).
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.IP CURL_SSLVERSION_TLSv1
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TLS v1.0 or later
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.IP CURL_SSLVERSION_SSLv2
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SSL v2 - refused
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.IP CURL_SSLVERSION_SSLv3
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SSL v3 - refused
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.IP CURL_SSLVERSION_TLSv1_0
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TLS v1.0 or later (Added in 7.34.0)
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.IP CURL_SSLVERSION_TLSv1_1
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TLS v1.1 or later (Added in 7.34.0)
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.IP CURL_SSLVERSION_TLSv1_2
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TLS v1.2 or later (Added in 7.34.0)
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.IP CURL_SSLVERSION_TLSv1_3
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TLS v1.3 or later (Added in 7.52.0)
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.RE
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The maximum TLS version can be set by using \fIone\fP of the
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CURL_SSLVERSION_MAX_ macros below. It is also possible to OR \fIone\fP of the
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CURL_SSLVERSION_ macros with \fIone\fP of the CURL_SSLVERSION_MAX_ macros.
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The MAX macros are not supported for WolfSSL.
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.RS
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.IP CURL_SSLVERSION_MAX_DEFAULT
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The flag defines the maximum supported TLS version by libcurl, or the default
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value from the SSL library is used. libcurl uses a sensible default maximum,
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which was TLS v1.2 up to before 7.61.0 and is TLS v1.3 since then - assuming
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the TLS library support it. (Added in 7.54.0)
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.IP CURL_SSLVERSION_MAX_TLSv1_0
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The flag defines maximum supported TLS version as TLS v1.0.
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(Added in 7.54.0)
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.IP CURL_SSLVERSION_MAX_TLSv1_1
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The flag defines maximum supported TLS version as TLS v1.1.
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(Added in 7.54.0)
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.IP CURL_SSLVERSION_MAX_TLSv1_2
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The flag defines maximum supported TLS version as TLS v1.2.
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(Added in 7.54.0)
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.IP CURL_SSLVERSION_MAX_TLSv1_3
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The flag defines maximum supported TLS version as TLS v1.3.
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(Added in 7.54.0)
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.RE
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In versions of curl prior to 7.54 the CURL_SSLVERSION_TLS options were
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documented to allow \fIonly\fP the specified TLS version, but behavior was
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inconsistent depending on the TLS library.
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.SH DEFAULT
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CURL_SSLVERSION_DEFAULT
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.SH PROTOCOLS
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All TLS based protocols: HTTPS, FTPS, IMAPS, POP3S, SMTPS etc.
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.SH EXAMPLE
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.nf
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CURL *curl = curl_easy_init();
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if(curl) {
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curl_easy_setopt(curl, CURLOPT_URL, "https://example.com");
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/* ask libcurl to use TLS version 1.0 or later */
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curl_easy_setopt(curl, CURLOPT_SSLVERSION, (long)CURL_SSLVERSION_TLSv1);
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/* Perform the request */
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curl_easy_perform(curl);
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}
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.fi
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.SH AVAILABILITY
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SSLv2 and SSLv3 are refused completely since curl 7.77.0
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SSLv2 is disabled by default since 7.18.1. Other SSL versions availability may
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vary depending on which backend libcurl has been built to use.
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SSLv3 is disabled by default since 7.39.0.
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.SH RETURN VALUE
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Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION if not.
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.SH "SEE ALSO"
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.BR CURLOPT_USE_SSL "(3), " CURLOPT_HTTP_VERSION "(3), "
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.BR CURLOPT_PROXY_SSLVERSION "(3), " CURLOPT_IPRESOLVE "(3) "
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