openssl/doc/man3/SSL_CIPHER_get_name.pod
Paul Yang 22d1a340b6 Add two missing SSL_CIPHER_* functions
This is yet another 'code health' commit to respond to this round of code health
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Reviewed-by: Matt Caswell <matt@openssl.org>
Reviewed-by: Ben Kaduk <kaduk@mit.edu>
(Merged from https://github.com/openssl/openssl/pull/4107)
2017-08-30 13:54:28 -05:00

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=pod
=head1 NAME
SSL_CIPHER_get_name,
SSL_CIPHER_standard_name,
OPENSSL_cipher_name,
SSL_CIPHER_get_bits,
SSL_CIPHER_get_version,
SSL_CIPHER_description,
SSL_CIPHER_get_cipher_nid,
SSL_CIPHER_get_digest_nid,
SSL_CIPHER_get_handshake_digest,
SSL_CIPHER_get_kx_nid,
SSL_CIPHER_get_auth_nid,
SSL_CIPHER_is_aead,
SSL_CIPHER_find,
SSL_CIPHER_get_id
- get SSL_CIPHER properties
=head1 SYNOPSIS
#include <openssl/ssl.h>
const char *SSL_CIPHER_get_name(const SSL_CIPHER *cipher);
const char *SSL_CIPHER_standard_name(const SSL_CIPHER *cipher);
const char *OPENSSL_cipher_name(const char *stdname);
int SSL_CIPHER_get_bits(const SSL_CIPHER *cipher, int *alg_bits);
char *SSL_CIPHER_get_version(const SSL_CIPHER *cipher);
char *SSL_CIPHER_description(const SSL_CIPHER *cipher, char *buf, int size);
int SSL_CIPHER_get_cipher_nid(const SSL_CIPHER *c);
int SSL_CIPHER_get_digest_nid(const SSL_CIPHER *c);
const EVP_MD *SSL_CIPHER_get_handshake_digest(const SSL_CIPHER *c);
int SSL_CIPHER_get_kx_nid(const SSL_CIPHER *c);
int SSL_CIPHER_get_auth_nid(const SSL_CIPHER *c);
int SSL_CIPHER_is_aead(const SSL_CIPHER *c);
const SSL_CIPHER *SSL_CIPHER_find(SSL *ssl, const unsigned char *ptr);
uint32_t SSL_CIPHER_get_id(const SSL_CIPHER *c);
=head1 DESCRIPTION
SSL_CIPHER_get_name() returns a pointer to the name of B<cipher>. If the
B<cipher> is NULL, it returns "(NONE)".
SSL_CIPHER_standard_name() returns a pointer to the standard RFC name of
B<cipher>. If the B<cipher> is NULL, it returns "(NONE)". If the B<cipher>
has no standard name, it returns B<NULL>. If B<cipher> was defined in both
SSLv3 and TLS, it returns the TLS name.
OPENSSL_cipher_name() returns a pointer to the OpenSSL name of B<stdname>.
If the B<stdname> is NULL, or B<stdname> has no corresponding OpenSSL name,
it returns "(NONE)". Where both exist, B<stdname> should be the TLS name rather
than the SSLv3 name.
SSL_CIPHER_get_bits() returns the number of secret bits used for B<cipher>.
If B<cipher> is NULL, 0 is returned.
SSL_CIPHER_get_version() returns string which indicates the SSL/TLS protocol
version that first defined the cipher. It returns "(NONE)" if B<cipher> is NULL.
SSL_CIPHER_get_cipher_nid() returns the cipher NID corresponding to B<c>.
If there is no cipher (e.g. for cipher suites with no encryption) then
B<NID_undef> is returned.
SSL_CIPHER_get_digest_nid() returns the digest NID corresponding to the MAC
used by B<c> during record encryption/decryption. If there is no digest (e.g.
for AEAD cipher suites) then B<NID_undef> is returned.
SSL_CIPHER_get_handshake_digest() returns an EVP_MD for the digest used during
the SSL/TLS handshake when using the SSL_CIPHER B<c>. Note that this may be
different to the digest used to calculate the MAC for encrypted records.
SSL_CIPHER_get_kx_nid() returns the key exchange NID corresponding to the method
used by B<c>. If there is no key exchange, then B<NID_undef> is returned.
If any appropriate key exchange algorithm can be used (as in the case of TLS 1.3
cipher suites) B<NID_kx_any> is returned. Examples (not comprehensive):
NID_kx_rsa
NID_kx_ecdhe
NID_kx_dhe
NID_kx_psk
SSL_CIPHER_get_auth_nid() returns the authentication NID corresponding to the method
used by B<c>. If there is no authentication, then B<NID_undef> is returned.
If any appropriate authentication algorithm can be used (as in the case of
TLS 1.3 cipher suites) B<NID_auth_any> is returned. Examples (not comprehensive):
NID_auth_rsa
NID_auth_ecdsa
NID_auth_psk
SSL_CIPHER_is_aead() returns 1 if the cipher B<c> is AEAD (e.g. GCM or
ChaCha20/Poly1305), and 0 if it is not AEAD.
SSL_CIPHER_find() returns a B<SSL_CIPHER> structure which has the cipher ID stored
in B<ptr>. The B<ptr> parameter is a two element array of B<char>, which stores the
two-byte TLS cipher ID (as allocated by IANA) in network byte order. This parameter
is usually retrieved from a TLS packet by using functions like L<SSL_early_get0_ciphers(3)>.
SSL_CIPHER_find() returns NULL if an error occurs or the indicated cipher is not found.
SSL_CIPHER_get_id() returns the ID of the given cipher B<c>. The ID here is an
OpenSSL-specific concept, which stores a prefix of 0x0300 in the higher two bytes,
and the IANA-specified chipher suite ID in the lower two bytes. For instance,
TLS_RSA_WITH_NULL_MD5 has IANA ID "0x00, 0x01", but the SSL_CIPHER_get_id()
function will return an ID with value 0x03000001.
SSL_CIPHER_description() returns a textual description of the cipher used
into the buffer B<buf> of length B<len> provided. If B<buf> is provided, it
must be at least 128 bytes, otherwise a buffer will be allocated using
OPENSSL_malloc(). If the provided buffer is too small, or the allocation fails,
B<NULL> is returned.
The string returned by SSL_CIPHER_description() consists of several fields
separated by whitespace:
=over 4
=item <ciphername>
Textual representation of the cipher name.
=item <protocol version>
Protocol version, such as B<TLSv1.2>, when the cipher was first defined.
=item Kx=<key exchange>
Key exchange method such as B<RSA>, B<ECDHE>, etc.
=item Au=<authentication>
Authentication method such as B<RSA>, B<None>, etc.. None is the
representation of anonymous ciphers.
=item Enc=<symmetric encryption method>
Encryption method, with number of secret bits, such as B<AESGCM(128)>.
=item Mac=<message authentication code>
Message digest, such as B<SHA256>.
=back
Some examples for the output of SSL_CIPHER_description():
ECDHE-RSA-AES256-GCM-SHA256 TLSv1.2 Kx=ECDH Au=RSA Enc=AESGCM(256) Mac=AEAD
RSA-PSK-AES256-CBC-SHA384 TLSv1.0 Kx=RSAPSK Au=RSA Enc=AES(256) Mac=SHA384
=head1 HISTORY
SSL_CIPHER_get_version() was updated to always return the correct protocol
string in OpenSSL 1.1.0.
SSL_CIPHER_description() was changed to return B<NULL> on error,
rather than a fixed string, in OpenSSL 1.1.0.
SSL_CIPHER_get_handshake_digest() was added in OpenSSL 1.1.1.
SSL_CIPHER_standard_name() was globally available in OpenSSL 1.1.1. Before
OpenSSL 1.1.1, tracing (B<enable-ssl-trace> argument to Configure) was
required to enable this function.
OPENSSL_cipher_name() was added in OpenSSL 1.1.1.
=head1 SEE ALSO
L<ssl(7)>, L<SSL_get_current_cipher(3)>,
L<SSL_get_ciphers(3)>, L<ciphers(1)>
=head1 COPYRIGHT
Copyright 2000-2017 The OpenSSL Project Authors. All Rights Reserved.
Licensed under the OpenSSL license (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
L<https://www.openssl.org/source/license.html>.
=cut