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 op-
tion is only supported for Schannel (the native Windows SSL li-
brary). 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)
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.
SEE ALSO
CURLOPT_SSLVERSION(3), CURLOPT_SSL_CIPHER_LIST(3),
libcurl 7.81.0 November 26, 2021 CURLOPT_SSL_OPTIONS(3)
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