SSL_CTX_ADD1_CHAIN_CERT(3)           OpenSSL          SSL_CTX_ADD1_CHAIN_CERT(3)

       SSL_CTX_set0_chain, SSL_CTX_set1_chain, SSL_CTX_add0_chain_cert,
       SSL_CTX_add1_chain_cert, SSL_CTX_get0_chain_certs,
       SSL_CTX_clear_chain_certs, SSL_set0_chain, SSL_set1_chain,
       SSL_add0_chain_cert, SSL_add1_chain_cert, SSL_get0_chain_certs,
       SSL_clear_chain_certs, SSL_CTX_build_cert_chain, SSL_build_cert_chain,
       SSL_CTX_select_current_cert, SSL_select_current_cert,
       SSL_CTX_set_current_cert, SSL_set_current_cert - extra chain certificate

        #include <openssl/ssl.h>

        int SSL_CTX_set0_chain(SSL_CTX *ctx, STACK_OF(X509) *sk);
        int SSL_CTX_set1_chain(SSL_CTX *ctx, STACK_OF(X509) *sk);
        int SSL_CTX_add0_chain_cert(SSL_CTX *ctx, X509 *x509);
        int SSL_CTX_add1_chain_cert(SSL_CTX *ctx, X509 *x509);
        int SSL_CTX_get0_chain_certs(SSL_CTX *ctx, STACK_OF(X509) **sk);
        int SSL_CTX_clear_chain_certs(SSL_CTX *ctx);

        int SSL_set0_chain(SSL *ssl, STACK_OF(X509) *sk);
        int SSL_set1_chain(SSL *ssl, STACK_OF(X509) *sk);
        int SSL_add0_chain_cert(SSL *ssl, X509 *x509);
        int SSL_add1_chain_cert(SSL *ssl, X509 *x509);
        int SSL_get0_chain_certs(SSL *ssl, STACK_OF(X509) **sk);
        int SSL_clear_chain_certs(SSL *ssl);

        int SSL_CTX_build_cert_chain(SSL_CTX *ctx, flags);
        int SSL_build_cert_chain(SSL *ssl, flags);

        int SSL_CTX_select_current_cert(SSL_CTX *ctx, X509 *x509);
        int SSL_select_current_cert(SSL *ssl, X509 *x509);
        int SSL_CTX_set_current_cert(SSL_CTX *ctx, long op);
        int SSL_set_current_cert(SSL *ssl, long op);

       SSL_CTX_set0_chain() and SSL_CTX_set1_chain() set the certificate chain
       associated with the current certificate of ctx to sk.

       SSL_CTX_add0_chain_cert() and SSL_CTX_add1_chain_cert() append the single
       certificate x509 to the chain associated with the current certificate of

       SSL_CTX_get0_chain_certs() retrieves the chain associated with the
       current certificate of ctx.

       SSL_CTX_clear_chain_certs() clears any existing chain associated with the
       current certificate of ctx.  (This is implemented by calling
       SSL_CTX_set0_chain() with sk set to NULL).

       SSL_CTX_build_cert_chain() builds the certificate chain for ctx normally
       this uses the chain store or the verify store if the chain store is not
       set.  If the function is successful the built chain will replace any
       existing chain.  The flags parameter can be set to
       SSL_BUILD_CHAIN_FLAG_UNTRUSTED to use existing chain certificates as
       untrusted CAs, SSL_BUILD_CHAIN_FLAG_NO_ROOT to omit the root CA from the
       built chain, SSL_BUILD_CHAIN_FLAG_CHECK to use all existing chain
       certificates only to build the chain (effectively sanity checking and
       rearranging them if necessary), the flag
       SSL_BUILD_CHAIN_FLAG_IGNORE_ERROR ignores any errors during verification:
       if flag SSL_BUILD_CHAIN_FLAG_CLEAR_ERROR is also set verification errors
       are cleared from the error queue.

       Each of these functions operates on the current end entity (i.e. server
       or client) certificate. This is the last certificate loaded or selected
       on the corresponding ctx structure.

       SSL_CTX_select_current_cert() selects x509 as the current end entity
       certificate, but only if x509 has already been loaded into ctx using a
       function such as SSL_CTX_use_certificate().

       SSL_set0_chain(), SSL_set1_chain(), SSL_add0_chain_cert(),
       SSL_add1_chain_cert(), SSL_get0_chain_certs(), SSL_clear_chain_certs(),
       SSL_build_cert_chain(), SSL_select_current_cert() and
       SSL_set_current_cert() are similar except they apply to SSL structure

       SSL_CTX_set_current_cert() changes the current certificate to a value
       based on the op argument. Currently op can be SSL_CERT_SET_FIRST to use
       the first valid certificate or SSL_CERT_SET_NEXT to set the next valid
       certificate after the current certificate. These two operations can be
       used to iterate over all certificates in an SSL_CTX structure.

       SSL_set_current_cert() also supports the option SSL_CERT_SET_SERVER.  If
       ssl is a server and has sent a certificate to a connected client this
       option sets that certificate to the current certificate and returns 1.
       If the negotiated cipher suite is anonymous (and thus no certificate will
       be sent) 2 is returned and the current certificate is unchanged. If ssl
       is not a server or a certificate has not been sent 0 is returned and the
       current certificate is unchanged.

       All these functions are implemented as macros. Those containing a 1
       increment the reference count of the supplied certificate or chain so it
       must be freed at some point after the operation. Those containing a 0 do
       not increment reference counts and the supplied certificate or chain MUST
       NOT be freed after the operation.

       The chains associate with an SSL_CTX structure are copied to any SSL
       structures when SSL_new() is called. SSL structures will not be affected
       by any chains subsequently changed in the parent SSL_CTX.

       One chain can be set for each key type supported by a server. So, for
       example, an RSA and a DSA certificate can (and often will) have different

       The functions SSL_CTX_build_cert_chain() and SSL_build_cert_chain() can
       be used to check application configuration and to ensure any necessary
       subordinate CAs are sent in the correct order. Misconfigured applications
       sending incorrect certificate chains often cause problems with peers.

       For example an application can add any set of certificates using
       SSL_CTX_use_certificate_chain_file() then call SSL_CTX_build_cert_chain()
       with the option SSL_BUILD_CHAIN_FLAG_CHECK to check and reorder them.

       Applications can issue non fatal warnings when checking chains by setting
       the flag SSL_BUILD_CHAIN_FLAG_IGNORE_ERRORS and checking the return

       Calling SSL_CTX_build_cert_chain() or SSL_build_cert_chain() is more
       efficient than the automatic chain building as it is only performed once.
       Automatic chain building is performed on each new session.

       If any certificates are added using these functions no certificates added
       using SSL_CTX_add_extra_chain_cert() will be used.

       SSL_set_current_cert() with SSL_CERT_SET_SERVER return 1 for success, 2
       if no server certificate is used because the cipher suites is anonymous
       and 0 for failure.

       SSL_CTX_build_cert_chain() and SSL_build_cert_chain() return 1 for
       success and 0 for failure. If the flag SSL_BUILD_CHAIN_FLAG_IGNORE_ERROR
       and a verification error occurs then 2 is returned.

       All other functions return 1 for success and 0 for failure.

       ssl(7), SSL_CTX_add_extra_chain_cert(3)

       These functions were added in OpenSSL 1.0.2.

       Copyright 2013-2016 The OpenSSL Project Authors. All Rights Reserved.

       Licensed under the Apache License 2.0 (the "License").  You may not use
       this file except in compliance with the License.  You can obtain a copy
       in the file LICENSE in the source distribution or at

3.0.0-alpha12                      2021-02-18         SSL_CTX_ADD1_CHAIN_CERT(3)