| .\" ************************************************************************** |
| .\" * _ _ ____ _ |
| .\" * Project ___| | | | _ \| | |
| .\" * / __| | | | |_) | | |
| .\" * | (__| |_| | _ <| |___ |
| .\" * \___|\___/|_| \_\_____| |
| .\" * |
| .\" * Copyright (C) 1998 - 2020, Daniel Stenberg, <daniel@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.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. |
| .\" * |
| .\" ************************************************************************** |
| .\" |
| .TH CURLOPT_SSL_OPTIONS 3 "February 27, 2021" "libcurl 7.78.0" "curl_easy_setopt options" |
| |
| .SH NAME |
| CURLOPT_SSL_OPTIONS \- set SSL behavior options |
| .SH SYNOPSIS |
| #include <curl/curl.h> |
| |
| CURLcode curl_easy_setopt(CURL *handle, CURLOPT_SSL_OPTIONS, long bitmask); |
| .SH DESCRIPTION |
| Pass a long with a bitmask to tell libcurl about specific SSL |
| behaviors. Available bits: |
| .IP CURLSSLOPT_ALLOW_BEAST |
| Tells libcurl to not attempt to use any workarounds for a security flaw in the |
| SSL3 and TLS1.0 protocols. If this option isn't used or this bit is set to 0, |
| the SSL layer libcurl uses may use a work-around for this flaw although it |
| might cause interoperability problems with some (older) SSL |
| implementations. WARNING: avoiding this work-around lessens the security, and |
| by setting this option to 1 you ask for exactly that. This option is only |
| supported for Secure Transport, NSS and OpenSSL. |
| .IP CURLSSLOPT_NO_REVOKE |
| Tells libcurl to disable certificate revocation checks for those SSL backends |
| where such behavior is present. This option is only supported for Schannel |
| (the native Windows SSL library), with an exception in the case of Windows' |
| Untrusted Publishers block list which it seems can't be bypassed. (Added in |
| 7.44.0) |
| .IP CURLSSLOPT_NO_PARTIALCHAIN |
| Tells libcurl to not accept "partial" certificate chains, which it otherwise |
| does by default. This option is only supported for OpenSSL and will fail the |
| certificate verification if the chain ends with an intermediate certificate |
| and not with a root cert. (Added in 7.68.0) |
| .IP CURLSSLOPT_REVOKE_BEST_EFFORT |
| Tells libcurl to ignore certificate revocation checks in case of missing or |
| offline distribution points for those SSL backends where such behavior is |
| present. This option is only supported for Schannel (the native Windows SSL |
| library). If combined with \fICURLSSLOPT_NO_REVOKE\fP, the latter takes |
| precedence. (Added in 7.70.0) |
| .IP CURLSSLOPT_NATIVE_CA |
| Tell libcurl to use the operating system's native CA store for certificate |
| verification. Works only on Windows when built to use OpenSSL. This option is |
| experimental and behavior is subject to change. |
| (Added in 7.71.0) |
| .IP CURLSSLOPT_AUTO_CLIENT_CERT |
| Tell libcurl to automatically locate and use a client certificate for |
| authentication, when requested by the server. This option is only supported |
| for Schannel (the native Windows SSL library). Prior to 7.77.0 this was the |
| default behavior in libcurl with Schannel. Since the server can request any |
| certificate that supports client authentication in the OS certificate store it |
| could be a privacy violation and unexpected. |
| (Added in 7.77.0) |
| .SH DEFAULT |
| 0 |
| .SH PROTOCOLS |
| All TLS-based protocols |
| .SH EXAMPLE |
| .nf |
| CURL *curl = curl_easy_init(); |
| if(curl) { |
| curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/"); |
| /* weaken TLS only for use with silly servers */ |
| curl_easy_setopt(curl, CURLOPT_SSL_OPTIONS, CURLSSLOPT_ALLOW_BEAST | |
| CURLSSLOPT_NO_REVOKE); |
| ret = curl_easy_perform(curl); |
| curl_easy_cleanup(curl); |
| } |
| .fi |
| .SH AVAILABILITY |
| Added in 7.25.0 |
| .SH RETURN VALUE |
| Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION if not. |
| .SH "SEE ALSO" |
| .BR CURLOPT_SSLVERSION "(3), " CURLOPT_SSL_CIPHER_LIST "(3), " |
