plucky (3) CURLOPT_SSL_OPTIONS.3.gz

Provided by: libcurl4-doc_8.12.1-2ubuntu1_all bug

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)

       CURLSSLOPT_EARLYDATA
              Tell libcurl to try sending application data as TLS1.3 early data. This option is  only  supported
              for  GnuTLS.  This  option  works on a best effort basis, in cases when it wasn't possible to send
              early data the request is resent normally post-handshake.  This option does not  work  when  using
              QUIC.  (Added in 8.11.0)

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

       curl_easy_setopt(3) returns a CURLcode indicating success or error.

       CURLE_OK (0) means everything was OK, non-zero means an error occurred, see libcurl-errors(3).

SEE ALSO

       CURLOPT_PROXY_SSL_OPTIONS(3), CURLOPT_SSLVERSION(3), CURLOPT_SSL_CIPHER_LIST(3)