CURLOPT_SSL_OPTIONS(3) Library Functions Manual 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
behaviors. Available bits:
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
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
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 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 fails 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. If you set this option and also set a
CA certificate file or directory then during verification those
certificates are searched in addition to the native CA store.
Works with wolfSSL on Windows, Linux (Debian, Ubuntu, Gentoo,
Fedora, RHEL), macOS, Android and iOS (added in 8.3.0), with
GnuTLS (added in 8.5.0) or on Windows when built to use OpenSSL
(Added in 7.71.0).
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)
DEFAULT
0
PROTOCOLS
This functionality affects all TLS based protocols: HTTPS, FTPS, IMAPS,
POP3S, SMTPS etc.
All TLS backends support this option.
EXAMPLE
int main(void)
{
CURL *curl = curl_easy_init();
if(curl) {
CURLcode res;
curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/");
/* weaken TLS only for use with silly servers */
curl_easy_setopt(curl, CURLOPT_SSL_OPTIONS, (long)CURLSSLOPT_ALLOW_BEAST |
CURLSSLOPT_NO_REVOKE);
res = curl_easy_perform(curl);
curl_easy_cleanup(curl);
}
}
AVAILABILITY
Added in curl 7.25.0
RETURN VALUE
Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION
if not.
SEE ALSO
CURLOPT_PROXY_SSL_OPTIONS(3), CURLOPT_SSLVERSION(3),
CURLOPT_SSL_CIPHER_LIST(3)
libcurl 2024-08-05 CURLOPT_SSL_OPTIONS(3)
curl 8.9.1 - Generated Wed Aug 7 15:27:59 CDT 2024