144 lines
3.3 KiB
Markdown
144 lines
3.3 KiB
Markdown
---
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c: Copyright (C) Daniel Stenberg, <daniel.se>, et al.
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SPDX-License-Identifier: curl
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Title: CURLOPT_SSLVERSION
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Section: 3
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Source: libcurl
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See-also:
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- CURLOPT_HTTP_VERSION (3)
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- CURLOPT_IPRESOLVE (3)
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- CURLOPT_PROXY_SSLVERSION (3)
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- CURLOPT_USE_SSL (3)
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---
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# NAME
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CURLOPT_SSLVERSION - preferred TLS/SSL version
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# SYNOPSIS
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~~~c
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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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~~~
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# 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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## 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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## CURL_SSLVERSION_TLSv1
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TLS v1.0 or later
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## CURL_SSLVERSION_SSLv2
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SSL v2 - refused
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## CURL_SSLVERSION_SSLv3
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SSL v3 - refused
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## CURL_SSLVERSION_TLSv1_0
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TLS v1.0 or later (Added in 7.34.0)
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## CURL_SSLVERSION_TLSv1_1
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TLS v1.1 or later (Added in 7.34.0)
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## CURL_SSLVERSION_TLSv1_2
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TLS v1.2 or later (Added in 7.34.0)
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## CURL_SSLVERSION_TLSv1_3
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TLS v1.3 or later (Added in 7.52.0)
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The maximum TLS version can be set by using *one* of the
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CURL_SSLVERSION_MAX_ macros below. It is also possible to OR *one* of the
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CURL_SSLVERSION_ macros with *one* of the CURL_SSLVERSION_MAX_ macros.
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The MAX macros are not supported for WolfSSL.
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## 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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## 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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## 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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## 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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## 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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In versions of curl prior to 7.54 the CURL_SSLVERSION_TLS options were
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documented to allow *only* the specified TLS version, but behavior was
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inconsistent depending on the TLS library.
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# DEFAULT
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CURL_SSLVERSION_DEFAULT
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# PROTOCOLS
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All TLS based protocols: HTTPS, FTPS, IMAPS, POP3S, SMTPS etc.
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# EXAMPLE
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~~~c
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int main(void)
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{
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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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}
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~~~
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# 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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# RETURN VALUE
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Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION if not.
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