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SSL_new.3ossl - Man Page

create an SSL structure for a connection


 #include <openssl/ssl.h>

 SSL *SSL_dup(SSL *s);
 SSL *SSL_new(SSL_CTX *ctx);
 int SSL_up_ref(SSL *s);


SSL_new() creates a new SSL structure which is needed to hold the data for a TLS/SSL connection. The new structure inherits the settings of the underlying context ctx: connection method, options, verification settings, timeout settings. An SSL structure is reference counted. Creating an SSL structure for the first time increments the reference count. Freeing it (using SSL_free) decrements it. When the reference count drops to zero, any memory or resources allocated to the SSL structure are freed.

SSL_up_ref() increments the reference count for an existing SSL structure.

The function SSL_dup() creates and returns a new SSL structure from the same SSL_CTX that was used to create s. It additionally duplicates a subset of the settings in s into the new SSL object.

For SSL_dup() to work, the connection MUST be in its initial state and MUST NOT have yet started the SSL handshake.  For connections that are not in their initial state SSL_dup() just increments an internal reference count and returns the same handle.  It may be possible to use SSL_clear(3) to recycle an SSL handle that is not in its initial state for reuse, but this is best avoided.  Instead, save and restore the session, if desired, and construct a fresh handle for each connection.

The subset of settings in s that are duplicated are:

any session data if configured (including the session_id_context)

any tmp_dh settings set via SSL_set_tmp_dh(3), SSL_set_tmp_dh_callback(3), or SSL_set_dh_auto(3)

any configured certificates, private keys or certificate chains

any configured signature algorithms, or client signature algorithms

any DANE settings

any Options set via SSL_set_options(3)

any Mode set via SSL_set_mode(3)

any minimum or maximum protocol settings set via SSL_set_min_proto_version(3) or SSL_set_max_proto_version(3) (Note: Only from OpenSSL 1.1.1h and above)

any verify mode, callback or depth set via SSL_set_verify(3) or SSL_set_verify_depth(3) or any configured X509 verification parameters

any msg callback or info callback set via SSL_set_msg_callback(3) or SSL_set_info_callback(3)

any default password callback set via SSL_set_default_passwd_cb(3)

any session id generation callback set via SSL_set_generate_session_id(3)

any configured Cipher List

initial accept (server) or connect (client) state

the max cert list value set via SSL_set_max_cert_list(3)

the read_ahead value set via SSL_set_read_ahead(3)

application specific data set via SSL_set_ex_data(3)

any CA list or client CA list set via SSL_set0_CA_list(3), SSL_set0_client_CA_list() or similar functions

any security level settings or callbacks

any configured serverinfo data

any configured PSK identity hint

any configured custom extensions

any client certificate types configured via SSL_set1_client_certificate_types

SSL_dup() is not supported on QUIC SSL objects and returns NULL if called on such an object.

Return Values

The following return values can occur:


The creation of a new SSL structure failed. Check the error stack to find out the reason.

Pointer to an SSL structure

The return value points to an allocated SSL structure.

SSL_up_ref() returns 1 for success and 0 for failure.

See Also

SSL_free(3), SSL_clear(3), SSL_CTX_set_options(3), SSL_get_SSL_CTX(3), ssl(7)

Referenced By

openssl-threads.7ossl(7), ossl-guide-quic-multi-stream.7ossl(7), ossl-guide-tls-client-block.7ossl(7), SSL_alloc_buffers.3ossl(3), SSL_clear.3ossl(3), SSL_CTX_dane_enable.3ossl(3), SSL_CTX_set_cert_verify_callback.3ossl(3), SSL_CTX_set_max_cert_list.3ossl(3), SSL_CTX_set_msg_callback.3ossl(3), SSL_CTX_set_options.3ossl(3), SSL_CTX_set_quiet_shutdown.3ossl(3), SSL_CTX_set_record_padding_callback.3ossl(3), SSL_CTX_set_ssl_version.3ossl(3), SSL_CTX_set_verify.3ossl(3), SSL_CTX_use_certificate.3ossl(3), SSL_free.3ossl(3), SSL_get0_connection.3ossl(3), SSL_get_SSL_CTX.3ossl(3), SSL_set_connect_state.3ossl(3), SSL_set_default_stream_mode.3ossl(3).

The man pages SSL_dup.3ossl(3) and SSL_up_ref.3ossl(3) are aliases of SSL_new.3ossl(3).

2024-06-06 3.2.2 OpenSSL