Ubuntu Manpage: SSL_get1_supported_ciphers, SSL_get_client_ciphers, SSL_get_ciphers, SSL_CTX_get

Provided by: libssl-doc_3.0.13-0ubuntu3.5_all

NAME

       SSL_get1_supported_ciphers, SSL_get_client_ciphers, SSL_get_ciphers, SSL_CTX_get_ciphers,
       SSL_bytes_to_cipher_list, SSL_get_cipher_list, SSL_get_shared_ciphers - get list of available SSL_CIPHERs

SYNOPSIS

        #include <openssl/ssl.h>

        STACK_OF(SSL_CIPHER) *SSL_get_ciphers(const SSL *ssl);
        STACK_OF(SSL_CIPHER) *SSL_CTX_get_ciphers(const SSL_CTX *ctx);
        STACK_OF(SSL_CIPHER) *SSL_get1_supported_ciphers(SSL *s);
        STACK_OF(SSL_CIPHER) *SSL_get_client_ciphers(const SSL *ssl);
        int SSL_bytes_to_cipher_list(SSL *s, const unsigned char *bytes, size_t len,
                                     int isv2format, STACK_OF(SSL_CIPHER) **sk,
                                     STACK_OF(SSL_CIPHER) **scsvs);
        const char *SSL_get_cipher_list(const SSL *ssl, int priority);
        char *SSL_get_shared_ciphers(const SSL *s, char *buf, int size);

DESCRIPTION

SSL_get_ciphers() returns the stack of available SSL_CIPHERs for ssl, sorted by preference. If ssl is
NULL or no ciphers are available, NULL is returned.

SSL_CTX_get_ciphers() returns the stack of available SSL_CIPHERs for ctx.

SSL_get1_supported_ciphers() returns the stack of enabled SSL_CIPHERs for ssl as would be sent in a
ClientHello (that is, sorted by preference). The list depends on settings like the cipher list, the
supported protocol versions, the security level, and the enabled signature algorithms. SRP and PSK
ciphers are only enabled if the appropriate callbacks or settings have been applied. The list of ciphers
that would be sent in a ClientHello can differ from the list of ciphers that would be acceptable when
acting as a server. For example, additional ciphers may be usable by a server if there is a gap in the
list of supported protocols, and some ciphers may not be usable by a server if there is not a suitable
certificate configured. If ssl is NULL or no ciphers are available, NULL is returned.

SSL_get_client_ciphers() returns the stack of available SSL_CIPHERs matching the list received from the
client on ssl. If ssl is NULL, no ciphers are available, or ssl is not operating in server mode, NULL is
returned.

SSL_bytes_to_cipher_list() treats the supplied len octets in bytes as a wire-protocol cipher suite
specification (in the three-octet-per-cipher SSLv2 wire format if isv2format is nonzero; otherwise the
two-octet SSLv3/TLS wire format), and parses the cipher suites supported by the library into the returned
stacks of SSL_CIPHER objects sk and Signalling Cipher-Suite Values scsvs. Unsupported cipher suites are
ignored. Returns 1 on success and 0 on failure.

SSL_get_cipher_list() returns a pointer to the name of the SSL_CIPHER listed for ssl with priority. If
ssl is NULL, no ciphers are available, or there are less ciphers than priority available, NULL is
returned.

SSL_get_shared_ciphers() creates a colon separated and NUL terminated list of SSL_CIPHER names that are
available in both the client and the server. buf is the buffer that should be populated with the list of
names and size is the size of that buffer. A pointer to buf is returned on success or NULL on error. If
the supplied buffer is not large enough to contain the complete list of names then a truncated list of
names will be returned. Note that just because a ciphersuite is available (i.e. it is configured in the
cipher list) and shared by both the client and the server it does not mean that it is enabled (see the
description of SSL_get1_supported_ciphers() above). This function will return available shared
ciphersuites whether or not they are enabled. This is a server side function only and must only be called
after the completion of the initial handshake.

NOTES

       The details of the ciphers obtained by SSL_get_ciphers(), SSL_CTX_get_ciphers()
       SSL_get1_supported_ciphers() and SSL_get_client_ciphers() can be obtained using the
       SSL_CIPHER_get_name(3) family of functions.

       Call SSL_get_cipher_list() with priority starting from 0 to obtain the sorted list of available ciphers,
       until NULL is returned.

       Note: SSL_get_ciphers(), SSL_CTX_get_ciphers() and SSL_get_client_ciphers() return a pointer to an
       internal cipher stack, which will be freed later on when the SSL or SSL_SESSION object is freed.
       Therefore, the calling code MUST NOT free the return value itself.

       The stack returned by SSL_get1_supported_ciphers() should be freed using sk_SSL_CIPHER_free().

       The stacks returned by SSL_bytes_to_cipher_list() should be freed using sk_SSL_CIPHER_free().

RETURN VALUES

       See DESCRIPTION

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