Ubuntu Manpage: SSL_get1_supported_ciphers, SSL_get_client_ciphers, SSL_get_ciphers, SSL_CTX_get

Provided by: libssl-doc_1.1.1-1ubuntu2.1~18.04.23_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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