SSL_set_current_cert(3)

NAME

       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_cur-
       rent_cert, SSL_set_current_cert - extra chain certificate processing

SYNOPSIS

        #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);

DESCRIPTION

       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 sin-
       gle certificate x509 to the chain associated with the current certifi-
       cate of ctx.

       SSL_CTX_get0_chain_certs() retrieves the chain associated with the cur-
       rent 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 nor-
       mally 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 verifica-
       tion: 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_cur-
       rent_cert() are similar except they apply to SSL structure ssl.

       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 ciphersuite 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.

NOTES

       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 differ-
       ent chains.

       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 applica-
       tions 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 set-
       ting the flag SSL_BUILD_CHAIN_FLAG_IGNORE_ERRORS and checking the
       return value.

       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.

RETURN VALUES

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

       SSL_CTX_build_cert_chain() and SSL_build_cert_chain() return 1 for suc-
       cess 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.

SEE ALSO

       SSL_CTX_add_extra_chain_cert(3)

HISTORY

       These functions were first added to OpenSSL 1.0.2.

1.0.2t                            2019-09-10        SSL_CTX_add1_chain_cert(3)