]>
Commit | Line | Data |
---|---|---|
3db935a9 DSH |
1 | =pod |
2 | ||
3 | =head1 NAME | |
4 | ||
5 | SSL_CONF_cmd - send configuration command | |
6 | ||
7 | =head1 SYNOPSIS | |
8 | ||
9 | #include <openssl/ssl.h> | |
10 | ||
11 | int SSL_CONF_cmd(SSL_CONF_CTX *cctx, const char *cmd, const char *value); | |
ec2f7e56 DSH |
12 | int SSL_CONF_cmd_value_type(SSL_CONF_CTX *cctx, const char *cmd); |
13 | int SSL_CONF_finish(SSL_CONF_CTX *cctx); | |
3db935a9 DSH |
14 | |
15 | =head1 DESCRIPTION | |
16 | ||
17 | The function SSL_CONF_cmd() performs configuration operation B<cmd> with | |
18 | optional parameter B<value> on B<ctx>. Its purpose is to simplify application | |
19 | configuration of B<SSL_CTX> or B<SSL> structures by providing a common | |
13cfb043 DSH |
20 | framework for command line options or configuration files. |
21 | ||
ec2f7e56 DSH |
22 | SSL_CONF_cmd_value_type() returns the type of value that B<cmd> refers to. |
23 | ||
24 | The function SSL_CONF_finish() must be called after all configuration | |
25 | operations have been completed. It is used to finalise any operations | |
26 | or to process defaults. | |
27 | ||
13cfb043 DSH |
28 | =head1 SUPPORTED COMMAND LINE COMMANDS |
29 | ||
30 | Currently supported B<cmd> names for command lines (i.e. when the | |
31 | flag B<SSL_CONF_CMDLINE> is set) are listed below. Note: all B<cmd> names | |
4b64e0cb | 32 | are case sensitive. Unless otherwise stated commands can be used by |
13cfb043 DSH |
33 | both clients and servers and the B<value> parameter is not used. The default |
34 | prefix for command line commands is B<-> and that is reflected below. | |
35 | ||
36 | =over 4 | |
37 | ||
38 | =item B<-sigalgs> | |
39 | ||
40 | This sets the supported signature algorithms for TLS v1.2. For clients this | |
41 | value is used directly for the supported signature algorithms extension. For | |
42 | servers it is used to determine which signature algorithms to support. | |
43 | ||
44 | The B<value> argument should be a colon separated list of signature algorithms | |
45 | in order of decreasing preference of the form B<algorithm+hash>. B<algorithm> | |
46 | is one of B<RSA>, B<DSA> or B<ECDSA> and B<hash> is a supported algorithm | |
47 | OID short name such as B<SHA1>, B<SHA224>, B<SHA256>, B<SHA384> of B<SHA512>. | |
48 | Note: algorithm and hash names are case sensitive. | |
49 | ||
50 | If this option is not set then all signature algorithms supported by the | |
51 | OpenSSL library are permissible. | |
52 | ||
53 | =item B<-client_sigalgs> | |
54 | ||
55 | This sets the supported signature algorithms associated with client | |
56 | authentication for TLS v1.2. For servers the value is used in the supported | |
57 | signature algorithms field of a certificate request. For clients it is | |
58 | used to determine which signature algorithm to with the client certificate. | |
59 | If a server does not request a certificate this option has no effect. | |
60 | ||
61 | The syntax of B<value> is identical to B<-sigalgs>. If not set then | |
62 | the value set for B<-sigalgs> will be used instead. | |
63 | ||
64 | =item B<-curves> | |
65 | ||
65f2a565 DSH |
66 | This sets the supported elliptic curves. For clients the curves are |
67 | sent using the supported curves extension. For servers it is used | |
13cfb043 DSH |
68 | to determine which curve to use. This setting affects curves used for both |
69 | signatures and key exchange, if applicable. | |
70 | ||
71 | The B<value> argument is a colon separated list of curves. The curve can be | |
72 | either the B<NIST> name (e.g. B<P-256>) or an OpenSSL OID name (e.g | |
73 | B<prime256v1>). Curve names are case sensitive. | |
74 | ||
75 | =item B<-named_curve> | |
76 | ||
7946ab33 | 77 | This sets the temporary curve used for ephemeral ECDH modes. Only used by |
13cfb043 DSH |
78 | servers |
79 | ||
80 | The B<value> argument is a curve name or the special value B<auto> which | |
81 | picks an appropriate curve based on client and server preferences. The curve | |
82 | can be either the B<NIST> name (e.g. B<P-256>) or an OpenSSL OID name | |
83 | (e.g B<prime256v1>). Curve names are case sensitive. | |
84 | ||
85 | =item B<-cipher> | |
86 | ||
87 | Sets the cipher suite list to B<value>. Note: syntax checking of B<value> is | |
7946ab33 | 88 | currently not performed unless a B<SSL> or B<SSL_CTX> structure is |
13cfb043 DSH |
89 | associated with B<cctx>. |
90 | ||
ec2f7e56 DSH |
91 | =item B<-cert> |
92 | ||
93 | Attempts to use the file B<value> as the certificate for the appropriate | |
fc1d88f0 RS |
94 | context. It currently uses SSL_CTX_use_certificate_chain_file() if an B<SSL_CTX> |
95 | structure is set or SSL_use_certificate_file() with filetype PEM if an B<SSL> | |
ec2f7e56 DSH |
96 | structure is set. This option is only supported if certificate operations |
97 | are permitted. | |
98 | ||
99 | =item B<-key> | |
100 | ||
101 | Attempts to use the file B<value> as the private key for the appropriate | |
102 | context. This option is only supported if certificate operations | |
103 | are permitted. Note: if no B<-key> option is set then a private key is | |
2011b169 | 104 | not loaded unless the flag B<SSL_CONF_FLAG_REQUIRE_PRIVATE> is set. |
ec2f7e56 | 105 | |
c557f921 DSH |
106 | =item B<-dhparam> |
107 | ||
108 | Attempts to use the file B<value> as the set of temporary DH parameters for | |
109 | the appropriate context. This option is only supported if certificate | |
110 | operations are permitted. | |
111 | ||
7946ab33 KR |
112 | =item B<-min_protocol>, B<-max_protocol> |
113 | ||
114 | Sets the minimum and maximum supported protocol. | |
57ce7b61 | 115 | Currently supported protocol values are B<SSLv3>, B<TLSv1>, |
869e978c KR |
116 | B<TLSv1.1>, B<TLSv1.2> for TLS and B<DTLSv1>, B<DTLSv1.2> for DTLS, |
117 | and B<None> for no limit. | |
57ce7b61 VD |
118 | If the either bound is not specified then only the other bound applies, |
119 | if specified. | |
120 | To restrict the supported protocol versions use these commands rather | |
121 | than the deprecated alternative commands below. | |
7946ab33 | 122 | |
45f55f6a | 123 | =item B<-no_ssl3>, B<-no_tls1>, B<-no_tls1_1>, B<-no_tls1_2> |
13cfb043 | 124 | |
7946ab33 | 125 | Disables protocol support for SSLv3, TLS 1.0, TLS 1.1 or TLS 1.2 |
57ce7b61 VD |
126 | by setting the corresponding options B<SSL_OP_NO_SSL3>, B<SSL_OP_NO_TLS1>, |
127 | B<SSL_OP_NO_TLS1_1> and B<SSL_OP_NO_TLS1_2> respectively. | |
128 | These options are deprecated, instead use B<-min_protocol> and B<-max_protocol>. | |
13cfb043 DSH |
129 | |
130 | =item B<-bugs> | |
131 | ||
132 | Various bug workarounds are set, same as setting B<SSL_OP_ALL>. | |
133 | ||
134 | =item B<-no_comp> | |
135 | ||
136 | Disables support for SSL/TLS compression, same as setting B<SSL_OP_NO_COMPRESS>. | |
137 | ||
138 | =item B<-no_ticket> | |
139 | ||
140 | Disables support for session tickets, same as setting B<SSL_OP_NO_TICKET>. | |
141 | ||
142 | =item B<-serverpref> | |
143 | ||
144 | Use server and not client preference order when determining which cipher suite, | |
145 | signature algorithm or elliptic curve to use for an incoming connection. | |
146 | Equivalent to B<SSL_OP_CIPHER_SERVER_PREFERENCE>. Only used by servers. | |
147 | ||
f0ef019d DSH |
148 | =item B<-no_resumption_on_reneg> |
149 | ||
150 | set SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION flag. Only used by servers. | |
151 | ||
13cfb043 DSH |
152 | =item B<-legacyrenegotiation> |
153 | ||
154 | permits the use of unsafe legacy renegotiation. Equivalent to setting | |
155 | B<SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION>. | |
156 | ||
157 | =item B<-legacy_server_connect>, B<-no_legacy_server_connect> | |
158 | ||
159 | permits or prohibits the use of unsafe legacy renegotiation for OpenSSL | |
160 | clients only. Equivalent to setting or clearing B<SSL_OP_LEGACY_SERVER_CONNECT>. | |
161 | Set by default. | |
162 | ||
163 | =item B<-strict> | |
164 | ||
165 | enables strict mode protocol handling. Equivalent to setting | |
166 | B<SSL_CERT_FLAG_TLS_STRICT>. | |
167 | ||
168 | =item B<-debug_broken_protocol> | |
169 | ||
170 | disables various checks and permits several kinds of broken protocol behaviour | |
171 | for testing purposes: it should B<NEVER> be used in anything other than a test | |
172 | environment. Only supported if OpenSSL is configured with | |
173 | B<-DOPENSSL_SSL_DEBUG_BROKEN_PROTOCOL>. | |
174 | ||
175 | =back | |
3db935a9 DSH |
176 | |
177 | =head1 SUPPORTED CONFIGURATION FILE COMMANDS | |
178 | ||
179 | Currently supported B<cmd> names for configuration files (i.e. when the | |
180 | flag B<SSL_CONF_FLAG_FILE> is set) are listed below. All configuration file | |
854dfcd8 | 181 | B<cmd> names are case insensitive so B<signaturealgorithms> is recognised |
c7b7984a | 182 | as well as B<SignatureAlgorithms>. Unless otherwise stated the B<value> names |
3db935a9 DSH |
183 | are also case insensitive. |
184 | ||
185 | Note: the command prefix (if set) alters the recognised B<cmd> values. | |
186 | ||
187 | =over 4 | |
188 | ||
65f2a565 | 189 | =item B<CipherString> |
3db935a9 DSH |
190 | |
191 | Sets the cipher suite list to B<value>. Note: syntax checking of B<value> is | |
7946ab33 | 192 | currently not performed unless an B<SSL> or B<SSL_CTX> structure is |
3db935a9 DSH |
193 | associated with B<cctx>. |
194 | ||
ec2f7e56 DSH |
195 | =item B<Certificate> |
196 | ||
197 | Attempts to use the file B<value> as the certificate for the appropriate | |
fc1d88f0 RS |
198 | context. It currently uses SSL_CTX_use_certificate_chain_file() if an B<SSL_CTX> |
199 | structure is set or SSL_use_certificate_file() with filetype PEM if an B<SSL> | |
ec2f7e56 DSH |
200 | structure is set. This option is only supported if certificate operations |
201 | are permitted. | |
202 | ||
203 | =item B<PrivateKey> | |
204 | ||
205 | Attempts to use the file B<value> as the private key for the appropriate | |
206 | context. This option is only supported if certificate operations | |
2011b169 DSH |
207 | are permitted. Note: if no B<PrivateKey> option is set then a private key is |
208 | not loaded unless the B<SSL_CONF_FLAG_REQUIRE_PRIVATE> is set. | |
ec2f7e56 | 209 | |
429261d0 DSH |
210 | =item B<ChainCAFile>, B<ChainCAPath>, B<VerifyCAFile>, B<VerifyCAPath> |
211 | ||
212 | These options indicate a file or directory used for building certificate | |
213 | chains or verifying certificate chains. These options are only supported | |
214 | if certificate operations are permitted. | |
215 | ||
5b7f36e8 DSH |
216 | =item B<ServerInfoFile> |
217 | ||
218 | Attempts to use the file B<value> in the "serverinfo" extension using the | |
219 | function SSL_CTX_use_serverinfo_file. | |
220 | ||
c557f921 DSH |
221 | =item B<DHParameters> |
222 | ||
223 | Attempts to use the file B<value> as the set of temporary DH parameters for | |
224 | the appropriate context. This option is only supported if certificate | |
225 | operations are permitted. | |
226 | ||
3db935a9 DSH |
227 | =item B<SignatureAlgorithms> |
228 | ||
229 | This sets the supported signature algorithms for TLS v1.2. For clients this | |
230 | value is used directly for the supported signature algorithms extension. For | |
231 | servers it is used to determine which signature algorithms to support. | |
232 | ||
233 | The B<value> argument should be a colon separated list of signature algorithms | |
234 | in order of decreasing preference of the form B<algorithm+hash>. B<algorithm> | |
235 | is one of B<RSA>, B<DSA> or B<ECDSA> and B<hash> is a supported algorithm | |
236 | OID short name such as B<SHA1>, B<SHA224>, B<SHA256>, B<SHA384> of B<SHA512>. | |
237 | Note: algorithm and hash names are case sensitive. | |
238 | ||
239 | If this option is not set then all signature algorithms supported by the | |
240 | OpenSSL library are permissible. | |
241 | ||
242 | =item B<ClientSignatureAlgorithms> | |
243 | ||
244 | This sets the supported signature algorithms associated with client | |
245 | authentication for TLS v1.2. For servers the value is used in the supported | |
246 | signature algorithms field of a certificate request. For clients it is | |
c7b7984a | 247 | used to determine which signature algorithm to with the client certificate. |
3db935a9 DSH |
248 | |
249 | The syntax of B<value> is identical to B<SignatureAlgorithms>. If not set then | |
250 | the value set for B<SignatureAlgorithms> will be used instead. | |
251 | ||
252 | =item B<Curves> | |
253 | ||
65f2a565 DSH |
254 | This sets the supported elliptic curves. For clients the curves are |
255 | sent using the supported curves extension. For servers it is used | |
c7b7984a DSH |
256 | to determine which curve to use. This setting affects curves used for both |
257 | signatures and key exchange, if applicable. | |
3db935a9 DSH |
258 | |
259 | The B<value> argument is a colon separated list of curves. The curve can be | |
260 | either the B<NIST> name (e.g. B<P-256>) or an OpenSSL OID name (e.g | |
261 | B<prime256v1>). Curve names are case sensitive. | |
262 | ||
263 | =item B<ECDHParameters> | |
264 | ||
7946ab33 | 265 | This sets the temporary curve used for ephemeral ECDH modes. Only used by |
13cfb043 | 266 | servers |
3db935a9 DSH |
267 | |
268 | The B<value> argument is a curve name or the special value B<Automatic> which | |
c7b7984a DSH |
269 | picks an appropriate curve based on client and server preferences. The curve |
270 | can be either the B<NIST> name (e.g. B<P-256>) or an OpenSSL OID name | |
271 | (e.g B<prime256v1>). Curve names are case sensitive. | |
3db935a9 | 272 | |
7946ab33 KR |
273 | =item B<MinProtocol> |
274 | ||
275 | This sets the minimum supported SSL, TLS or DTLS version. | |
276 | ||
57ce7b61 VD |
277 | Currently supported protocol values are B<SSLv3>, B<TLSv1>, B<TLSv1.1>, |
278 | B<TLSv1.2>, B<DTLSv1> and B<DTLSv1.2>. | |
869e978c | 279 | The value B<None> will disable the limit. |
7946ab33 KR |
280 | |
281 | =item B<MaxProtocol> | |
282 | ||
283 | This sets the maximum supported SSL, TLS or DTLS version. | |
284 | ||
57ce7b61 VD |
285 | Currently supported protocol values are B<SSLv3>, B<TLSv1>, B<TLSv1.1>, |
286 | B<TLSv1.2>, B<DTLSv1> and B<DTLSv1.2>. | |
869e978c | 287 | The value B<None> will disable the limit. |
7946ab33 | 288 | |
3db935a9 DSH |
289 | =item B<Protocol> |
290 | ||
57ce7b61 VD |
291 | This can be used to enable or disable certain versions of the SSL, |
292 | TLS or DTLS protocol. | |
7946ab33 | 293 | |
57ce7b61 VD |
294 | The B<value> argument is a comma separated list of supported protocols |
295 | to enable or disable. | |
7946ab33 KR |
296 | If a protocol is preceded by B<-> that version is disabled. |
297 | ||
298 | All protocol versions are enabled by default. | |
57ce7b61 VD |
299 | You need to disable at least one protocol version for this setting have any |
300 | effect. | |
301 | Only enabling some protocol versions does not disable the other protocol | |
302 | versions. | |
7946ab33 | 303 | |
57ce7b61 VD |
304 | Currently supported protocol values are B<SSLv3>, B<TLSv1>, B<TLSv1.1>, |
305 | B<TLSv1.2>, B<DTLSv1> and B<DTLSv1.2>. | |
7946ab33 | 306 | The special value B<ALL> refers to all supported versions. |
3db935a9 | 307 | |
57ce7b61 VD |
308 | This can't enable protocols that are disabled using B<MinProtocol> |
309 | or B<MaxProtocol>, but can disable protocols that are still allowed | |
310 | by them. | |
7946ab33 KR |
311 | |
312 | The B<Protocol> command is fragile and deprecated; do not use it. | |
313 | Use B<MinProtocol> and B<MaxProtocol> instead. | |
57ce7b61 VD |
314 | If you do use B<Protocol>, make sure that the resulting range of enabled |
315 | protocols has no "holes", e.g. if TLS 1.0 and TLS 1.2 are both enabled, make | |
316 | sure to also leave TLS 1.1 enabled. | |
3db935a9 DSH |
317 | |
318 | =item B<Options> | |
319 | ||
320 | The B<value> argument is a comma separated list of various flags to set. | |
321 | If a flag string is preceded B<-> it is disabled. See the | |
322 | B<SSL_CTX_set_options> function for more details of individual options. | |
323 | ||
324 | Each option is listed below. Where an operation is enabled by default | |
325 | the B<-flag> syntax is needed to disable it. | |
326 | ||
327 | B<SessionTicket>: session ticket support, enabled by default. Inverse of | |
328 | B<SSL_OP_NO_TICKET>: that is B<-SessionTicket> is the same as setting | |
329 | B<SSL_OP_NO_TICKET>. | |
330 | ||
331 | B<Compression>: SSL/TLS compression support, enabled by default. Inverse | |
332 | of B<SSL_OP_NO_COMPRESSION>. | |
333 | ||
334 | B<EmptyFragments>: use empty fragments as a countermeasure against a | |
335 | SSL 3.0/TLS 1.0 protocol vulnerability affecting CBC ciphers. It | |
336 | is set by default. Inverse of B<SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS>. | |
337 | ||
c7b7984a | 338 | B<Bugs>: enable various bug workarounds. Same as B<SSL_OP_ALL>. |
3db935a9 | 339 | |
c7b7984a | 340 | B<DHSingle>: enable single use DH keys, set by default. Inverse of |
3db935a9 DSH |
341 | B<SSL_OP_DH_SINGLE>. Only used by servers. |
342 | ||
343 | B<ECDHSingle> enable single use ECDH keys, set by default. Inverse of | |
344 | B<SSL_OP_ECDH_SINGLE>. Only used by servers. | |
345 | ||
346 | B<ServerPreference> use server and not client preference order when | |
347 | determining which cipher suite, signature algorithm or elliptic curve | |
348 | to use for an incoming connection. Equivalent to | |
349 | B<SSL_OP_CIPHER_SERVER_PREFERENCE>. Only used by servers. | |
350 | ||
f0ef019d DSH |
351 | B<NoResumptionOnRenegotiation> set |
352 | B<SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION> flag. Only used by servers. | |
353 | ||
3db935a9 DSH |
354 | B<UnsafeLegacyRenegotiation> permits the use of unsafe legacy renegotiation. |
355 | Equivalent to B<SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION>. | |
356 | ||
357 | B<UnsafeLegacyServerConnect> permits the use of unsafe legacy renegotiation | |
358 | for OpenSSL clients only. Equivalent to B<SSL_OP_LEGACY_SERVER_CONNECT>. | |
359 | Set by default. | |
360 | ||
429261d0 DSH |
361 | =item B<VerifyMode> |
362 | ||
363 | The B<value> argument is a comma separated list of flags to set. | |
364 | ||
365 | B<Peer> enables peer verification: for clients only. | |
366 | ||
367 | B<Request> requests but does not require a certificate from the client. | |
368 | Servers only. | |
369 | ||
370 | B<Require> requests and requires a certificate from the client: an error | |
371 | occurs if the client does not present a certificate. Servers only. | |
372 | ||
373 | B<Once> requests a certificate from a client only on the initial connection: | |
374 | not when renegotiating. Servers only. | |
375 | ||
376 | =item B<ClientCAFile>, B<ClientCAPath> | |
377 | ||
378 | A file or directory of certificates in PEM format whose names are used as the | |
379 | set of acceptable names for client CAs. Servers only. This option is only | |
380 | supported if certificate operations are permitted. | |
381 | ||
3db935a9 DSH |
382 | =back |
383 | ||
ec2f7e56 DSH |
384 | =head1 SUPPORTED COMMAND TYPES |
385 | ||
386 | The function SSL_CONF_cmd_value_type() currently returns one of the following | |
387 | types: | |
388 | ||
389 | =over 4 | |
390 | ||
391 | =item B<SSL_CONF_TYPE_UNKNOWN> | |
392 | ||
393 | The B<cmd> string is unrecognised, this return value can be use to flag | |
394 | syntax errors. | |
395 | ||
396 | =item B<SSL_CONF_TYPE_STRING> | |
397 | ||
398 | The value is a string without any specific structure. | |
399 | ||
400 | =item B<SSL_CONF_TYPE_FILE> | |
401 | ||
402 | The value is a file name. | |
403 | ||
404 | =item B<SSL_CONF_TYPE_DIR> | |
405 | ||
406 | The value is a directory name. | |
407 | ||
656b2605 DSH |
408 | =item B<SSL_CONF_TYPE_NONE> |
409 | ||
410 | The value string is not used e.g. a command line option which doesn't take an | |
411 | argument. | |
412 | ||
fa9d77dc CR |
413 | =back |
414 | ||
3db935a9 DSH |
415 | =head1 NOTES |
416 | ||
417 | The order of operations is significant. This can be used to set either defaults | |
418 | or values which cannot be overridden. For example if an application calls: | |
419 | ||
87d9cafa | 420 | SSL_CONF_cmd(ctx, "Protocol", "-SSLv3"); |
3db935a9 DSH |
421 | SSL_CONF_cmd(ctx, userparam, uservalue); |
422 | ||
87d9cafa | 423 | it will disable SSLv3 support by default but the user can override it. If |
3db935a9 DSH |
424 | however the call sequence is: |
425 | ||
426 | SSL_CONF_cmd(ctx, userparam, uservalue); | |
87d9cafa | 427 | SSL_CONF_cmd(ctx, "Protocol", "-SSLv3"); |
3db935a9 | 428 | |
87d9cafa | 429 | SSLv3 is B<always> disabled and attempt to override this by the user are |
3db935a9 DSH |
430 | ignored. |
431 | ||
432 | By checking the return code of SSL_CTX_cmd() it is possible to query if a | |
433 | given B<cmd> is recognised, this is useful is SSL_CTX_cmd() values are | |
434 | mixed with additional application specific operations. | |
435 | ||
436 | For example an application might call SSL_CTX_cmd() and if it returns | |
437 | -2 (unrecognised command) continue with processing of application specific | |
438 | commands. | |
439 | ||
440 | Applications can also use SSL_CTX_cmd() to process command lines though the | |
441 | utility function SSL_CTX_cmd_argv() is normally used instead. One way | |
821244cf DSH |
442 | to do this is to set the prefix to an appropriate value using |
443 | SSL_CONF_CTX_set1_prefix(), pass the current argument to B<cmd> and the | |
444 | following argument to B<value> (which may be NULL). | |
3db935a9 DSH |
445 | |
446 | In this case if the return value is positive then it is used to skip that | |
447 | number of arguments as they have been processed by SSL_CTX_cmd(). If -2 is | |
448 | returned then B<cmd> is not recognised and application specific arguments | |
449 | can be checked instead. If -3 is returned a required argument is missing | |
450 | and an error is indicated. If 0 is returned some other error occurred and | |
451 | this can be reported back to the user. | |
452 | ||
7946ab33 | 453 | The function SSL_CONF_cmd_value_type() can be used by applications to |
ec2f7e56 DSH |
454 | check for the existence of a command or to perform additional syntax |
455 | checking or translation of the command value. For example if the return | |
456 | value is B<SSL_CONF_TYPE_FILE> an application could translate a relative | |
457 | pathname to an absolute pathname. | |
458 | ||
3db935a9 DSH |
459 | =head1 EXAMPLES |
460 | ||
461 | Set supported signature algorithms: | |
462 | ||
463 | SSL_CONF_cmd(ctx, "SignatureAlgorithms", "ECDSA+SHA256:RSA+SHA256:DSA+SHA256"); | |
464 | ||
7946ab33 KR |
465 | There are various ways to select the supported procotols. |
466 | ||
467 | This set the minimum protocol version to TLSv1, and so disables SSLv3. | |
468 | This is the recommended way to disable protocols. | |
469 | ||
470 | SSL_CONF_cmd(ctx, "MinProtocol", "TLSv1"); | |
471 | ||
472 | The following also disables SSLv3: | |
473 | ||
474 | SSL_CONF_cmd(ctx, "Protocol", "-SSLv3"); | |
475 | ||
57ce7b61 VD |
476 | The following will first enable all protocols, and then disable |
477 | SSLv3. | |
478 | If no protocol versions were disabled before this has the same effect as | |
479 | "-SSLv3", but if some versions were disables this will re-enable them before | |
480 | disabling SSLv3. | |
3db935a9 | 481 | |
87d9cafa | 482 | SSL_CONF_cmd(ctx, "Protocol", "ALL,-SSLv3"); |
3db935a9 DSH |
483 | |
484 | Only enable TLSv1.2: | |
485 | ||
7946ab33 KR |
486 | SSL_CONF_cmd(ctx, "MinProtocol", "TLSv1.2"); |
487 | SSL_CONF_cmd(ctx, "MaxProtocol", "TLSv1.2"); | |
488 | ||
489 | This also only enables TLSv1.2: | |
490 | ||
3db935a9 DSH |
491 | SSL_CONF_cmd(ctx, "Protocol", "-ALL,TLSv1.2"); |
492 | ||
493 | Disable TLS session tickets: | |
494 | ||
495 | SSL_CONF_cmd(ctx, "Options", "-SessionTicket"); | |
496 | ||
497 | Set supported curves to P-256, P-384: | |
498 | ||
499 | SSL_CONF_cmd(ctx, "Curves", "P-256:P-384"); | |
500 | ||
501 | Set automatic support for any elliptic curve for key exchange: | |
502 | ||
503 | SSL_CONF_cmd(ctx, "ECDHParameters", "Automatic"); | |
504 | ||
505 | =head1 RETURN VALUES | |
506 | ||
4365e4aa | 507 | SSL_CONF_cmd() returns 1 if the value of B<cmd> is recognised and B<value> is |
3db935a9 DSH |
508 | B<NOT> used and 2 if both B<cmd> and B<value> are used. In other words it |
509 | returns the number of arguments processed. This is useful when processing | |
510 | command lines. | |
511 | ||
512 | A return value of -2 means B<cmd> is not recognised. | |
513 | ||
514 | A return value of -3 means B<cmd> is recognised and the command requires a | |
515 | value but B<value> is NULL. | |
516 | ||
517 | A return code of 0 indicates that both B<cmd> and B<value> are valid but an | |
518 | error occurred attempting to perform the operation: for example due to an | |
519 | error in the syntax of B<value> in this case the error queue may provide | |
520 | additional information. | |
521 | ||
ec2f7e56 DSH |
522 | SSL_CONF_finish() returns 1 for success and 0 for failure. |
523 | ||
3db935a9 DSH |
524 | =head1 SEE ALSO |
525 | ||
9b86974e RS |
526 | L<SSL_CONF_CTX_new(3)>, |
527 | L<SSL_CONF_CTX_set_flags(3)>, | |
528 | L<SSL_CONF_CTX_set1_prefix(3)>, | |
529 | L<SSL_CONF_CTX_set_ssl_ctx(3)>, | |
530 | L<SSL_CONF_cmd_argv(3)> | |
3db935a9 DSH |
531 | |
532 | =head1 HISTORY | |
533 | ||
4365e4aa | 534 | SSL_CONF_cmd() was first added to OpenSSL 1.0.2 |
3db935a9 | 535 | |
57ce7b61 VD |
536 | B<SSL_OP_NO_SSL2> doesn't have effect since 1.1.0, but the macro is retained |
537 | for backwards compatibility. | |
45f55f6a | 538 | |
656b2605 DSH |
539 | B<SSL_CONF_TYPE_NONE> was first added to OpenSSL 1.1.0. In earlier versions of |
540 | OpenSSL passing a command which didn't take an argument would return | |
541 | B<SSL_CONF_TYPE_UNKNOWN>. | |
542 | ||
7946ab33 KR |
543 | B<MinProtocol> and B<MaxProtocol> where added in OpenSSL 1.1.0. |
544 | ||
3db935a9 | 545 | =cut |