CURLOPT_SSL_OPTIONS - SSL behavior options
#include <curl/curl.h> CURLcode curl_easy_setopt(CURL *handle, CURLOPT_SSL_OPTIONS, long bitmask);
CURLOPT_SSL_OPTIONS(3) curl_easy_setopt options CURLOPT_SSL_OPTIONS(3)
NAME
CURLOPT_SSL_OPTIONS - SSL behavior options
SYNOPSIS
#include <curl/curl.h>
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_SSL_OPTIONS, long bitmask);
DESCRIPTION
Pass a long with a bitmask to tell libcurl about specific SSL behav-
iors. Available bits:
CURLSSLOPT_ALLOW_BEAST
Tells libcurl to not attempt to use any workarounds for a secu-
rity flaw in the SSL3 and TLS1.0 protocols. If this option is
not 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 interop-
erability problems with some (older) SSL implementations. WARN-
ING: avoiding this work-around lessens the security, and by set-
ting this option to 1 you ask for exactly that. This option is
only supported for Secure Transport, NSS and OpenSSL.
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 cannot be bypassed. (Added in 7.44.0)
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)
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
CURLSSLOPT_NO_REVOKE, the latter takes precedence. (Added in
7.70.0)
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)
CURLSSLOPT_AUTO_CLIENT_CERT
Tell libcurl to automatically locate and use a client certifi-
cate 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 certifi-
cate that supports client authentication in the OS certificate
store it could be a privacy violation and unexpected. (Added in
7.77.0)
DEFAULT
0
PROTOCOLS
All TLS-based protocols
EXAMPLE
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);
}
AVAILABILITY
Added in 7.25.0
RETURN VALUE
Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION
if not.
ATTRIBUTES
See attributes(7) for descriptions of the following attributes:
+---------------+------------------+
|ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+---------------+------------------+
|Availability | web/curl |
+---------------+------------------+
|Stability | Uncommitted |
+---------------+------------------+
SEE ALSO
CURLOPT_SSLVERSION(3), CURLOPT_SSL_CIPHER_LIST(3),
NOTES
Source code for open source software components in Oracle Solaris can
be found at https://www.oracle.com/downloads/opensource/solaris-source-
code-downloads.html.
This software was built from source available at
https://github.com/oracle/solaris-userland. The original community
source was downloaded from https://curl.se/down-
load/curl-7.83.1.tar.bz2.
Further information about this software can be found on the open source
community website at http://curl.haxx.se/.
libcurl 7.83.1 November 26, 2021 CURLOPT_SSL_OPTIONS(3)