SSL_get_ciphers.3ossl 9.3 KB

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  135. .IX Title "SSL_GET_CIPHERS 3ossl"
  136. .TH SSL_GET_CIPHERS 3ossl "2024-09-03" "3.3.2" "OpenSSL"
  137. .\" For nroff, turn off justification. Always turn off hyphenation; it makes
  138. .\" way too many mistakes in technical documents.
  139. .if n .ad l
  140. .nh
  141. .SH "NAME"
  142. SSL_get1_supported_ciphers,
  143. SSL_get_client_ciphers,
  144. SSL_get_ciphers,
  145. SSL_CTX_get_ciphers,
  146. SSL_bytes_to_cipher_list,
  147. SSL_get_cipher_list,
  148. SSL_get_shared_ciphers
  149. \&\- get list of available SSL_CIPHERs
  150. .SH "SYNOPSIS"
  151. .IX Header "SYNOPSIS"
  152. .Vb 1
  153. \& #include <openssl/ssl.h>
  154. \&
  155. \& STACK_OF(SSL_CIPHER) *SSL_get_ciphers(const SSL *ssl);
  156. \& STACK_OF(SSL_CIPHER) *SSL_CTX_get_ciphers(const SSL_CTX *ctx);
  157. \& STACK_OF(SSL_CIPHER) *SSL_get1_supported_ciphers(SSL *s);
  158. \& STACK_OF(SSL_CIPHER) *SSL_get_client_ciphers(const SSL *ssl);
  159. \& int SSL_bytes_to_cipher_list(SSL *s, const unsigned char *bytes, size_t len,
  160. \& int isv2format, STACK_OF(SSL_CIPHER) **sk,
  161. \& STACK_OF(SSL_CIPHER) **scsvs);
  162. \& const char *SSL_get_cipher_list(const SSL *ssl, int priority);
  163. \& char *SSL_get_shared_ciphers(const SSL *s, char *buf, int size);
  164. .Ve
  165. .SH "DESCRIPTION"
  166. .IX Header "DESCRIPTION"
  167. \&\fBSSL_get_ciphers()\fR returns the stack of available SSL_CIPHERs for \fBssl\fR,
  168. sorted by preference. If \fBssl\fR is \s-1NULL\s0 or no ciphers are available, \s-1NULL\s0
  169. is returned.
  170. .PP
  171. \&\fBSSL_CTX_get_ciphers()\fR returns the stack of available SSL_CIPHERs for \fBctx\fR.
  172. .PP
  173. \&\fBSSL_get1_supported_ciphers()\fR returns the stack of enabled SSL_CIPHERs for
  174. \&\fBssl\fR as would be sent in a ClientHello (that is, sorted by preference).
  175. The list depends on settings like the cipher list, the supported protocol
  176. versions, the security level, and the enabled signature algorithms.
  177. \&\s-1SRP\s0 and \s-1PSK\s0 ciphers are only enabled if the appropriate callbacks or settings
  178. have been applied.
  179. The list of ciphers that would be sent in a ClientHello can differ from
  180. the list of ciphers that would be acceptable when acting as a server.
  181. For example, additional ciphers may be usable by a server if there is
  182. a gap in the list of supported protocols, and some ciphers may not be
  183. usable by a server if there is not a suitable certificate configured.
  184. If \fBssl\fR is \s-1NULL\s0 or no ciphers are available, \s-1NULL\s0 is returned.
  185. .PP
  186. \&\fBSSL_get_client_ciphers()\fR returns the stack of available SSL_CIPHERs matching the
  187. list received from the client on \fBssl\fR. If \fBssl\fR is \s-1NULL,\s0 no ciphers are
  188. available, or \fBssl\fR is not operating in server mode, \s-1NULL\s0 is returned.
  189. .PP
  190. \&\fBSSL_bytes_to_cipher_list()\fR treats the supplied \fBlen\fR octets in \fBbytes\fR
  191. as a wire-protocol cipher suite specification (in the three-octet-per-cipher
  192. SSLv2 wire format if \fBisv2format\fR is nonzero; otherwise the two-octet
  193. SSLv3/TLS wire format), and parses the cipher suites supported by the library
  194. into the returned stacks of \s-1SSL_CIPHER\s0 objects sk and Signalling Cipher-Suite
  195. Values scsvs. Unsupported cipher suites are ignored. Returns 1 on success
  196. and 0 on failure.
  197. .PP
  198. \&\fBSSL_get_cipher_list()\fR returns a pointer to the name of the \s-1SSL_CIPHER\s0
  199. listed for \fBssl\fR with \fBpriority\fR. If \fBssl\fR is \s-1NULL,\s0 no ciphers are
  200. available, or there are less ciphers than \fBpriority\fR available, \s-1NULL\s0
  201. is returned.
  202. .PP
  203. \&\fBSSL_get_shared_ciphers()\fR creates a colon separated and \s-1NUL\s0 terminated list of
  204. \&\s-1SSL_CIPHER\s0 names that are available in both the client and the server. \fBbuf\fR is
  205. the buffer that should be populated with the list of names and \fBsize\fR is the
  206. size of that buffer. A pointer to \fBbuf\fR is returned on success or \s-1NULL\s0 on
  207. error. If the supplied buffer is not large enough to contain the complete list
  208. of names then a truncated list of names will be returned. Note that just because
  209. a ciphersuite is available (i.e. it is configured in the cipher list) and shared
  210. by both the client and the server it does not mean that it is enabled (see the
  211. description of \fBSSL_get1_supported_ciphers()\fR above). This function will return
  212. available shared ciphersuites whether or not they are enabled. This is a server
  213. side function only and must only be called after the completion of the initial
  214. handshake.
  215. .SH "NOTES"
  216. .IX Header "NOTES"
  217. The details of the ciphers obtained by \fBSSL_get_ciphers()\fR, \fBSSL_CTX_get_ciphers()\fR
  218. \&\fBSSL_get1_supported_ciphers()\fR and \fBSSL_get_client_ciphers()\fR can be obtained using
  219. the \fBSSL_CIPHER_get_name\fR\|(3) family of functions.
  220. .PP
  221. Call \fBSSL_get_cipher_list()\fR with \fBpriority\fR starting from 0 to obtain the
  222. sorted list of available ciphers, until \s-1NULL\s0 is returned.
  223. .PP
  224. Note: \fBSSL_get_ciphers()\fR, \fBSSL_CTX_get_ciphers()\fR and \fBSSL_get_client_ciphers()\fR
  225. return a pointer to an internal cipher stack, which will be freed later on when
  226. the \s-1SSL\s0 or \s-1SSL_SESSION\s0 object is freed. Therefore, the calling code \fB\s-1MUST NOT\s0\fR
  227. free the return value itself.
  228. .PP
  229. The stack returned by \fBSSL_get1_supported_ciphers()\fR should be freed using
  230. \&\fBsk_SSL_CIPHER_free()\fR.
  231. .PP
  232. The stacks returned by \fBSSL_bytes_to_cipher_list()\fR should be freed using
  233. \&\fBsk_SSL_CIPHER_free()\fR.
  234. .SH "RETURN VALUES"
  235. .IX Header "RETURN VALUES"
  236. See \s-1DESCRIPTION\s0
  237. .SH "SEE ALSO"
  238. .IX Header "SEE ALSO"
  239. \&\fBssl\fR\|(7), \fBSSL_CTX_set_cipher_list\fR\|(3),
  240. \&\fBSSL_CIPHER_get_name\fR\|(3)
  241. .SH "COPYRIGHT"
  242. .IX Header "COPYRIGHT"
  243. Copyright 2000\-2018 The OpenSSL Project Authors. All Rights Reserved.
  244. .PP
  245. Licensed under the Apache License 2.0 (the \*(L"License\*(R"). You may not use
  246. this file except in compliance with the License. You can obtain a copy
  247. in the file \s-1LICENSE\s0 in the source distribution or at
  248. <https://www.openssl.org/source/license.html>.