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3db935a9 DSH |
1 | =pod |
2 | ||
3 | =head1 NAME | |
4 | ||
1722496f | 5 | SSL_CONF_cmd_value_type, |
3db935a9 DSH |
6 | SSL_CONF_cmd - send configuration command |
7 | ||
8 | =head1 SYNOPSIS | |
9 | ||
10 | #include <openssl/ssl.h> | |
11 | ||
12 | int SSL_CONF_cmd(SSL_CONF_CTX *cctx, const char *cmd, const char *value); | |
ec2f7e56 | 13 | int SSL_CONF_cmd_value_type(SSL_CONF_CTX *cctx, const char *cmd); |
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 | ||
13cfb043 DSH |
24 | =head1 SUPPORTED COMMAND LINE COMMANDS |
25 | ||
26 | Currently supported B<cmd> names for command lines (i.e. when the | |
27 | flag B<SSL_CONF_CMDLINE> is set) are listed below. Note: all B<cmd> names | |
4b64e0cb | 28 | are case sensitive. Unless otherwise stated commands can be used by |
13cfb043 DSH |
29 | both clients and servers and the B<value> parameter is not used. The default |
30 | prefix for command line commands is B<-> and that is reflected below. | |
31 | ||
32 | =over 4 | |
33 | ||
34 | =item B<-sigalgs> | |
35 | ||
36 | This sets the supported signature algorithms for TLS v1.2. For clients this | |
37 | value is used directly for the supported signature algorithms extension. For | |
38 | servers it is used to determine which signature algorithms to support. | |
39 | ||
40 | The B<value> argument should be a colon separated list of signature algorithms | |
41 | in order of decreasing preference of the form B<algorithm+hash>. B<algorithm> | |
42 | is one of B<RSA>, B<DSA> or B<ECDSA> and B<hash> is a supported algorithm | |
43 | OID short name such as B<SHA1>, B<SHA224>, B<SHA256>, B<SHA384> of B<SHA512>. | |
44 | Note: algorithm and hash names are case sensitive. | |
45 | ||
46 | If this option is not set then all signature algorithms supported by the | |
47 | OpenSSL library are permissible. | |
48 | ||
49 | =item B<-client_sigalgs> | |
50 | ||
51 | This sets the supported signature algorithms associated with client | |
52 | authentication for TLS v1.2. For servers the value is used in the supported | |
53 | signature algorithms field of a certificate request. For clients it is | |
54 | used to determine which signature algorithm to with the client certificate. | |
55 | If a server does not request a certificate this option has no effect. | |
56 | ||
57 | The syntax of B<value> is identical to B<-sigalgs>. If not set then | |
58 | the value set for B<-sigalgs> will be used instead. | |
59 | ||
47f7cf05 MC |
60 | =item B<-groups> |
61 | ||
62 | This sets the supported groups. For clients, the groups are | |
63 | sent using the supported groups extension. For servers, it is used | |
64 | to determine which group to use. This setting affects groups used for both | |
65 | signatures and key exchange, if applicable. It also affects the preferred | |
66 | key_share sent by a client in a TLSv1.3 compatible connection. | |
67 | ||
68 | The B<value> argument is a colon separated list of groups. The group can be | |
69 | either the B<NIST> name (e.g. B<P-256>), some other commonly used name where | |
70 | applicable (e.g. B<X25519>) or an OpenSSL OID name (e.g B<prime256v1>). Group | |
71 | names are case sensitive. The list should be in order of preference with the | |
72 | most preferred group first. The first listed group will be the one used for a | |
73 | key_share by a TLSv1.3 client. | |
74 | ||
75 | =item B<-curves> | |
76 | ||
77 | This is a synonym for the "-groups" command. | |
78 | ||
79 | ||
13cfb043 DSH |
80 | =item B<-named_curve> |
81 | ||
7946ab33 | 82 | This sets the temporary curve used for ephemeral ECDH modes. Only used by |
13cfb043 DSH |
83 | servers |
84 | ||
85 | The B<value> argument is a curve name or the special value B<auto> which | |
86 | picks an appropriate curve based on client and server preferences. The curve | |
87 | can be either the B<NIST> name (e.g. B<P-256>) or an OpenSSL OID name | |
88 | (e.g B<prime256v1>). Curve names are case sensitive. | |
89 | ||
90 | =item B<-cipher> | |
91 | ||
92 | Sets the cipher suite list to B<value>. Note: syntax checking of B<value> is | |
7946ab33 | 93 | currently not performed unless a B<SSL> or B<SSL_CTX> structure is |
13cfb043 DSH |
94 | associated with B<cctx>. |
95 | ||
ec2f7e56 DSH |
96 | =item B<-cert> |
97 | ||
98 | Attempts to use the file B<value> as the certificate for the appropriate | |
fc1d88f0 RS |
99 | context. It currently uses SSL_CTX_use_certificate_chain_file() if an B<SSL_CTX> |
100 | structure is set or SSL_use_certificate_file() with filetype PEM if an B<SSL> | |
ec2f7e56 DSH |
101 | structure is set. This option is only supported if certificate operations |
102 | are permitted. | |
103 | ||
104 | =item B<-key> | |
105 | ||
106 | Attempts to use the file B<value> as the private key for the appropriate | |
107 | context. This option is only supported if certificate operations | |
108 | are permitted. Note: if no B<-key> option is set then a private key is | |
2011b169 | 109 | not loaded unless the flag B<SSL_CONF_FLAG_REQUIRE_PRIVATE> is set. |
ec2f7e56 | 110 | |
c557f921 DSH |
111 | =item B<-dhparam> |
112 | ||
113 | Attempts to use the file B<value> as the set of temporary DH parameters for | |
114 | the appropriate context. This option is only supported if certificate | |
115 | operations are permitted. | |
116 | ||
c649d10d TS |
117 | =item B<-record_padding> |
118 | ||
119 | Attempts to pad TLS 1.3 records so that they are a multiple of B<value> in | |
120 | length on send. A B<value> of 0 or 1 turns off padding. Otherwise, the | |
121 | B<value> must be >1 or <=16384. | |
122 | ||
db0f35dd TS |
123 | =item B<-no_renegotiation> |
124 | ||
125 | Disables all attempts at renegotiation in TLSv1.2 and earlier, same as setting | |
126 | B<SSL_OP_NO_RENEGOTIATION>. | |
127 | ||
7946ab33 KR |
128 | =item B<-min_protocol>, B<-max_protocol> |
129 | ||
130 | Sets the minimum and maximum supported protocol. | |
57ce7b61 | 131 | Currently supported protocol values are B<SSLv3>, B<TLSv1>, |
869e978c KR |
132 | B<TLSv1.1>, B<TLSv1.2> for TLS and B<DTLSv1>, B<DTLSv1.2> for DTLS, |
133 | and B<None> for no limit. | |
57ce7b61 VD |
134 | If the either bound is not specified then only the other bound applies, |
135 | if specified. | |
136 | To restrict the supported protocol versions use these commands rather | |
137 | than the deprecated alternative commands below. | |
7946ab33 | 138 | |
582a17d6 | 139 | =item B<-no_ssl3>, B<-no_tls1>, B<-no_tls1_1>, B<-no_tls1_2>, B<-no_tls1_3> |
13cfb043 | 140 | |
582a17d6 MC |
141 | Disables protocol support for SSLv3, TLSv1.0, TLSv1.1, TLSv1.2 or TLSv1.3 by |
142 | setting the corresponding options B<SSL_OP_NO_SSLv3>, B<SSL_OP_NO_TLSv1>, | |
143 | B<SSL_OP_NO_TLSv1_1>, B<SSL_OP_NO_TLSv1_2> and B<SSL_OP_NO_TLSv1_3> | |
144 | respectively. These options are deprecated, instead use B<-min_protocol> and | |
145 | B<-max_protocol>. | |
13cfb043 DSH |
146 | |
147 | =item B<-bugs> | |
148 | ||
149 | Various bug workarounds are set, same as setting B<SSL_OP_ALL>. | |
150 | ||
dc5744cb | 151 | =item B<-comp> |
13cfb043 | 152 | |
cc5a9ba4 VD |
153 | Enables support for SSL/TLS compression, same as clearing |
154 | B<SSL_OP_NO_COMPRESSION>. | |
155 | This command was introduced in OpenSSL 1.1.0. | |
156 | As of OpenSSL 1.1.0, compression is off by default. | |
157 | ||
158 | =item B<-no_comp> | |
159 | ||
160 | Disables support for SSL/TLS compression, same as setting | |
161 | B<SSL_OP_NO_COMPRESSION>. | |
162 | As of OpenSSL 1.1.0, compression is off by default. | |
13cfb043 DSH |
163 | |
164 | =item B<-no_ticket> | |
165 | ||
166 | Disables support for session tickets, same as setting B<SSL_OP_NO_TICKET>. | |
167 | ||
168 | =item B<-serverpref> | |
169 | ||
170 | Use server and not client preference order when determining which cipher suite, | |
171 | signature algorithm or elliptic curve to use for an incoming connection. | |
172 | Equivalent to B<SSL_OP_CIPHER_SERVER_PREFERENCE>. Only used by servers. | |
173 | ||
e1c7871d TS |
174 | =item B<-prioritize_chacha> |
175 | ||
176 | Prioritize ChaCha ciphers when the client has a ChaCha20 cipher at the top of | |
177 | its preference list. This usually indicates a client without AES hardware | |
178 | acceleration (e.g. mobile) is in use. Equivalent to B<SSL_OP_PRIORITIZE_CHACHA>. | |
179 | Only used by servers. Requires B<-serverpref>. | |
180 | ||
f0ef019d DSH |
181 | =item B<-no_resumption_on_reneg> |
182 | ||
183 | set SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION flag. Only used by servers. | |
184 | ||
13cfb043 DSH |
185 | =item B<-legacyrenegotiation> |
186 | ||
187 | permits the use of unsafe legacy renegotiation. Equivalent to setting | |
188 | B<SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION>. | |
189 | ||
190 | =item B<-legacy_server_connect>, B<-no_legacy_server_connect> | |
191 | ||
192 | permits or prohibits the use of unsafe legacy renegotiation for OpenSSL | |
193 | clients only. Equivalent to setting or clearing B<SSL_OP_LEGACY_SERVER_CONNECT>. | |
194 | Set by default. | |
195 | ||
4e2bd9cb MC |
196 | =item B<-allow_no_dhe_kex> |
197 | ||
198 | In TLSv1.3 allow a non-(ec)dhe based key exchange mode on resumption. This means | |
199 | that there will be no forward secrecy for the resumed session. | |
200 | ||
13cfb043 DSH |
201 | =item B<-strict> |
202 | ||
203 | enables strict mode protocol handling. Equivalent to setting | |
204 | B<SSL_CERT_FLAG_TLS_STRICT>. | |
205 | ||
13cfb043 | 206 | =back |
3db935a9 DSH |
207 | |
208 | =head1 SUPPORTED CONFIGURATION FILE COMMANDS | |
209 | ||
210 | Currently supported B<cmd> names for configuration files (i.e. when the | |
211 | flag B<SSL_CONF_FLAG_FILE> is set) are listed below. All configuration file | |
854dfcd8 | 212 | B<cmd> names are case insensitive so B<signaturealgorithms> is recognised |
c7b7984a | 213 | as well as B<SignatureAlgorithms>. Unless otherwise stated the B<value> names |
3db935a9 DSH |
214 | are also case insensitive. |
215 | ||
216 | Note: the command prefix (if set) alters the recognised B<cmd> values. | |
217 | ||
218 | =over 4 | |
219 | ||
65f2a565 | 220 | =item B<CipherString> |
3db935a9 DSH |
221 | |
222 | Sets the cipher suite list to B<value>. Note: syntax checking of B<value> is | |
7946ab33 | 223 | currently not performed unless an B<SSL> or B<SSL_CTX> structure is |
3db935a9 DSH |
224 | associated with B<cctx>. |
225 | ||
ec2f7e56 DSH |
226 | =item B<Certificate> |
227 | ||
228 | Attempts to use the file B<value> as the certificate for the appropriate | |
fc1d88f0 RS |
229 | context. It currently uses SSL_CTX_use_certificate_chain_file() if an B<SSL_CTX> |
230 | structure is set or SSL_use_certificate_file() with filetype PEM if an B<SSL> | |
ec2f7e56 DSH |
231 | structure is set. This option is only supported if certificate operations |
232 | are permitted. | |
233 | ||
234 | =item B<PrivateKey> | |
235 | ||
236 | Attempts to use the file B<value> as the private key for the appropriate | |
237 | context. This option is only supported if certificate operations | |
2011b169 DSH |
238 | are permitted. Note: if no B<PrivateKey> option is set then a private key is |
239 | not loaded unless the B<SSL_CONF_FLAG_REQUIRE_PRIVATE> is set. | |
ec2f7e56 | 240 | |
429261d0 DSH |
241 | =item B<ChainCAFile>, B<ChainCAPath>, B<VerifyCAFile>, B<VerifyCAPath> |
242 | ||
243 | These options indicate a file or directory used for building certificate | |
244 | chains or verifying certificate chains. These options are only supported | |
245 | if certificate operations are permitted. | |
246 | ||
5a185729 DSH |
247 | =item B<RequestCAFile> |
248 | ||
249 | This option indicates a file containing a set of certificates in PEM form. | |
250 | The subject names of the certificates are sent to the peer in the | |
251 | B<certificate_authorities> extension for TLS 1.3 (in ClientHello or | |
252 | CertificateRequest) or in a certificate request for previous versions or | |
253 | TLS. | |
254 | ||
5b7f36e8 DSH |
255 | =item B<ServerInfoFile> |
256 | ||
257 | Attempts to use the file B<value> in the "serverinfo" extension using the | |
258 | function SSL_CTX_use_serverinfo_file. | |
259 | ||
c557f921 DSH |
260 | =item B<DHParameters> |
261 | ||
262 | Attempts to use the file B<value> as the set of temporary DH parameters for | |
263 | the appropriate context. This option is only supported if certificate | |
264 | operations are permitted. | |
265 | ||
c649d10d TS |
266 | =item B<RecordPadding> |
267 | ||
268 | Attempts to pad TLS 1.3 records so that they are a multiple of B<value> in | |
269 | length on send. A B<value> of 0 or 1 turns off padding. Otherwise, the | |
270 | B<value> must be >1 or <=16384. | |
271 | ||
db0f35dd TS |
272 | =item B<NoRenegotiation> |
273 | ||
274 | Disables all attempts at renegotiation in TLSv1.2 and earlier, same as setting | |
275 | B<SSL_OP_NO_RENEGOTIATION>. | |
276 | ||
3db935a9 DSH |
277 | =item B<SignatureAlgorithms> |
278 | ||
279 | This sets the supported signature algorithms for TLS v1.2. For clients this | |
280 | value is used directly for the supported signature algorithms extension. For | |
281 | servers it is used to determine which signature algorithms to support. | |
282 | ||
283 | The B<value> argument should be a colon separated list of signature algorithms | |
284 | in order of decreasing preference of the form B<algorithm+hash>. B<algorithm> | |
285 | is one of B<RSA>, B<DSA> or B<ECDSA> and B<hash> is a supported algorithm | |
286 | OID short name such as B<SHA1>, B<SHA224>, B<SHA256>, B<SHA384> of B<SHA512>. | |
287 | Note: algorithm and hash names are case sensitive. | |
288 | ||
289 | If this option is not set then all signature algorithms supported by the | |
290 | OpenSSL library are permissible. | |
291 | ||
292 | =item B<ClientSignatureAlgorithms> | |
293 | ||
294 | This sets the supported signature algorithms associated with client | |
295 | authentication for TLS v1.2. For servers the value is used in the supported | |
296 | signature algorithms field of a certificate request. For clients it is | |
c7b7984a | 297 | used to determine which signature algorithm to with the client certificate. |
3db935a9 DSH |
298 | |
299 | The syntax of B<value> is identical to B<SignatureAlgorithms>. If not set then | |
300 | the value set for B<SignatureAlgorithms> will be used instead. | |
301 | ||
47f7cf05 | 302 | =item B<Groups> |
3db935a9 | 303 | |
47f7cf05 MC |
304 | This sets the supported groups. For clients, the groups are |
305 | sent using the supported groups extension. For servers, it is used | |
306 | to determine which group to use. This setting affects groups used for both | |
307 | signatures and key exchange, if applicable. It also affects the preferred | |
308 | key_share sent by a client in a TLSv1.3 compatible connection. | |
3db935a9 | 309 | |
47f7cf05 MC |
310 | The B<value> argument is a colon separated list of groups. The group can be |
311 | either the B<NIST> name (e.g. B<P-256>), some other commonly used name where | |
312 | applicable (e.g. B<X25519>) or an OpenSSL OID name (e.g B<prime256v1>). Group | |
313 | names are case sensitive. The list should be in order of preference with the | |
314 | most preferred group first. The first listed group will be the one used for a | |
315 | key_share by a TLSv1.3 client. | |
316 | ||
317 | =item B<Curves> | |
318 | ||
319 | This is a synonym for the "Groups" command. | |
3db935a9 | 320 | |
7946ab33 KR |
321 | =item B<MinProtocol> |
322 | ||
323 | This sets the minimum supported SSL, TLS or DTLS version. | |
324 | ||
57ce7b61 VD |
325 | Currently supported protocol values are B<SSLv3>, B<TLSv1>, B<TLSv1.1>, |
326 | B<TLSv1.2>, B<DTLSv1> and B<DTLSv1.2>. | |
869e978c | 327 | The value B<None> will disable the limit. |
7946ab33 KR |
328 | |
329 | =item B<MaxProtocol> | |
330 | ||
331 | This sets the maximum supported SSL, TLS or DTLS version. | |
332 | ||
57ce7b61 VD |
333 | Currently supported protocol values are B<SSLv3>, B<TLSv1>, B<TLSv1.1>, |
334 | B<TLSv1.2>, B<DTLSv1> and B<DTLSv1.2>. | |
869e978c | 335 | The value B<None> will disable the limit. |
7946ab33 | 336 | |
3db935a9 DSH |
337 | =item B<Protocol> |
338 | ||
57ce7b61 VD |
339 | This can be used to enable or disable certain versions of the SSL, |
340 | TLS or DTLS protocol. | |
7946ab33 | 341 | |
57ce7b61 VD |
342 | The B<value> argument is a comma separated list of supported protocols |
343 | to enable or disable. | |
7946ab33 KR |
344 | If a protocol is preceded by B<-> that version is disabled. |
345 | ||
346 | All protocol versions are enabled by default. | |
57ce7b61 VD |
347 | You need to disable at least one protocol version for this setting have any |
348 | effect. | |
349 | Only enabling some protocol versions does not disable the other protocol | |
350 | versions. | |
7946ab33 | 351 | |
57ce7b61 VD |
352 | Currently supported protocol values are B<SSLv3>, B<TLSv1>, B<TLSv1.1>, |
353 | B<TLSv1.2>, B<DTLSv1> and B<DTLSv1.2>. | |
7946ab33 | 354 | The special value B<ALL> refers to all supported versions. |
3db935a9 | 355 | |
57ce7b61 VD |
356 | This can't enable protocols that are disabled using B<MinProtocol> |
357 | or B<MaxProtocol>, but can disable protocols that are still allowed | |
358 | by them. | |
7946ab33 KR |
359 | |
360 | The B<Protocol> command is fragile and deprecated; do not use it. | |
361 | Use B<MinProtocol> and B<MaxProtocol> instead. | |
57ce7b61 VD |
362 | If you do use B<Protocol>, make sure that the resulting range of enabled |
363 | protocols has no "holes", e.g. if TLS 1.0 and TLS 1.2 are both enabled, make | |
364 | sure to also leave TLS 1.1 enabled. | |
3db935a9 DSH |
365 | |
366 | =item B<Options> | |
367 | ||
368 | The B<value> argument is a comma separated list of various flags to set. | |
8106cb8b VD |
369 | If a flag string is preceded B<-> it is disabled. |
370 | See the L<SSL_CTX_set_options(3)> function for more details of | |
371 | individual options. | |
3db935a9 DSH |
372 | |
373 | Each option is listed below. Where an operation is enabled by default | |
374 | the B<-flag> syntax is needed to disable it. | |
375 | ||
376 | B<SessionTicket>: session ticket support, enabled by default. Inverse of | |
377 | B<SSL_OP_NO_TICKET>: that is B<-SessionTicket> is the same as setting | |
378 | B<SSL_OP_NO_TICKET>. | |
379 | ||
380 | B<Compression>: SSL/TLS compression support, enabled by default. Inverse | |
381 | of B<SSL_OP_NO_COMPRESSION>. | |
382 | ||
383 | B<EmptyFragments>: use empty fragments as a countermeasure against a | |
384 | SSL 3.0/TLS 1.0 protocol vulnerability affecting CBC ciphers. It | |
385 | is set by default. Inverse of B<SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS>. | |
386 | ||
c7b7984a | 387 | B<Bugs>: enable various bug workarounds. Same as B<SSL_OP_ALL>. |
3db935a9 | 388 | |
c7b7984a | 389 | B<DHSingle>: enable single use DH keys, set by default. Inverse of |
3db935a9 DSH |
390 | B<SSL_OP_DH_SINGLE>. Only used by servers. |
391 | ||
e1c7871d | 392 | B<ECDHSingle>: enable single use ECDH keys, set by default. Inverse of |
3db935a9 DSH |
393 | B<SSL_OP_ECDH_SINGLE>. Only used by servers. |
394 | ||
e1c7871d | 395 | B<ServerPreference>: use server and not client preference order when |
3db935a9 DSH |
396 | determining which cipher suite, signature algorithm or elliptic curve |
397 | to use for an incoming connection. Equivalent to | |
398 | B<SSL_OP_CIPHER_SERVER_PREFERENCE>. Only used by servers. | |
399 | ||
e1c7871d TS |
400 | B<PrioritizeChaCha>: prioritizes ChaCha ciphers when the client has a |
401 | ChaCha20 cipher at the top of its preference list. This usually indicates | |
402 | a mobile client is in use. Equivalent to B<SSL_OP_PRIORITIZE_CHACHA>. | |
403 | Only used by servers. | |
404 | ||
405 | B<NoResumptionOnRenegotiation>: set | |
f0ef019d DSH |
406 | B<SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION> flag. Only used by servers. |
407 | ||
e1c7871d | 408 | B<UnsafeLegacyRenegotiation>: permits the use of unsafe legacy renegotiation. |
3db935a9 DSH |
409 | Equivalent to B<SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION>. |
410 | ||
e1c7871d | 411 | B<UnsafeLegacyServerConnect>: permits the use of unsafe legacy renegotiation |
3db935a9 DSH |
412 | for OpenSSL clients only. Equivalent to B<SSL_OP_LEGACY_SERVER_CONNECT>. |
413 | Set by default. | |
414 | ||
b3618f44 EK |
415 | B<EncryptThenMac>: use encrypt-then-mac extension, enabled by |
416 | default. Inverse of B<SSL_OP_NO_ENCRYPT_THEN_MAC>: that is, | |
417 | B<-EncryptThenMac> is the same as setting B<SSL_OP_NO_ENCRYPT_THEN_MAC>. | |
4e2bd9cb MC |
418 | |
419 | B<AllowNoDHEKEX>: In TLSv1.3 allow a non-(ec)dhe based key exchange mode on | |
420 | resumption. This means that there will be no forward secrecy for the resumed | |
421 | session. Equivalent to B<SSL_OP_ALLOW_NO_DHE_KEX>. | |
b3618f44 | 422 | |
429261d0 DSH |
423 | =item B<VerifyMode> |
424 | ||
425 | The B<value> argument is a comma separated list of flags to set. | |
426 | ||
427 | B<Peer> enables peer verification: for clients only. | |
428 | ||
429 | B<Request> requests but does not require a certificate from the client. | |
430 | Servers only. | |
431 | ||
432 | B<Require> requests and requires a certificate from the client: an error | |
433 | occurs if the client does not present a certificate. Servers only. | |
434 | ||
435 | B<Once> requests a certificate from a client only on the initial connection: | |
436 | not when renegotiating. Servers only. | |
437 | ||
9d75dce3 TS |
438 | B<RequestPostHandshake> configures the connection to support requests but does |
439 | not require a certificate from the client post-handshake. A certificate will | |
440 | not be requested during the initial handshake. The server application must | |
441 | provide a mechanism to request a certificate post-handshake. Servers only. | |
442 | TLSv1.3 only. | |
443 | ||
444 | B<RequiresPostHandshake> configures the connection to support requests and | |
445 | requires a certificate from the client post-handshake: an error occurs if the | |
446 | client does not present a certificate. A certificate will not be requested | |
447 | during the initial handshake. The server application must provide a mechanism | |
448 | to request a certificate post-handshake. Servers only. TLSv1.3 only. | |
449 | ||
429261d0 DSH |
450 | =item B<ClientCAFile>, B<ClientCAPath> |
451 | ||
452 | A file or directory of certificates in PEM format whose names are used as the | |
453 | set of acceptable names for client CAs. Servers only. This option is only | |
454 | supported if certificate operations are permitted. | |
455 | ||
3db935a9 DSH |
456 | =back |
457 | ||
ec2f7e56 DSH |
458 | =head1 SUPPORTED COMMAND TYPES |
459 | ||
460 | The function SSL_CONF_cmd_value_type() currently returns one of the following | |
461 | types: | |
462 | ||
463 | =over 4 | |
464 | ||
465 | =item B<SSL_CONF_TYPE_UNKNOWN> | |
466 | ||
467 | The B<cmd> string is unrecognised, this return value can be use to flag | |
468 | syntax errors. | |
469 | ||
470 | =item B<SSL_CONF_TYPE_STRING> | |
471 | ||
472 | The value is a string without any specific structure. | |
473 | ||
474 | =item B<SSL_CONF_TYPE_FILE> | |
475 | ||
476 | The value is a file name. | |
477 | ||
478 | =item B<SSL_CONF_TYPE_DIR> | |
479 | ||
480 | The value is a directory name. | |
481 | ||
656b2605 DSH |
482 | =item B<SSL_CONF_TYPE_NONE> |
483 | ||
484 | The value string is not used e.g. a command line option which doesn't take an | |
485 | argument. | |
486 | ||
fa9d77dc CR |
487 | =back |
488 | ||
3db935a9 DSH |
489 | =head1 NOTES |
490 | ||
491 | The order of operations is significant. This can be used to set either defaults | |
492 | or values which cannot be overridden. For example if an application calls: | |
493 | ||
87d9cafa | 494 | SSL_CONF_cmd(ctx, "Protocol", "-SSLv3"); |
3db935a9 DSH |
495 | SSL_CONF_cmd(ctx, userparam, uservalue); |
496 | ||
87d9cafa | 497 | it will disable SSLv3 support by default but the user can override it. If |
3db935a9 DSH |
498 | however the call sequence is: |
499 | ||
500 | SSL_CONF_cmd(ctx, userparam, uservalue); | |
87d9cafa | 501 | SSL_CONF_cmd(ctx, "Protocol", "-SSLv3"); |
3db935a9 | 502 | |
87d9cafa | 503 | SSLv3 is B<always> disabled and attempt to override this by the user are |
3db935a9 DSH |
504 | ignored. |
505 | ||
f5f85f75 | 506 | By checking the return code of SSL_CONF_cmd() it is possible to query if a |
44e69951 | 507 | given B<cmd> is recognised, this is useful if SSL_CONF_cmd() values are |
3db935a9 DSH |
508 | mixed with additional application specific operations. |
509 | ||
f5f85f75 | 510 | For example an application might call SSL_CONF_cmd() and if it returns |
3db935a9 DSH |
511 | -2 (unrecognised command) continue with processing of application specific |
512 | commands. | |
513 | ||
f5f85f75 JS |
514 | Applications can also use SSL_CONF_cmd() to process command lines though the |
515 | utility function SSL_CONF_cmd_argv() is normally used instead. One way | |
821244cf DSH |
516 | to do this is to set the prefix to an appropriate value using |
517 | SSL_CONF_CTX_set1_prefix(), pass the current argument to B<cmd> and the | |
518 | following argument to B<value> (which may be NULL). | |
3db935a9 DSH |
519 | |
520 | In this case if the return value is positive then it is used to skip that | |
f5f85f75 | 521 | number of arguments as they have been processed by SSL_CONF_cmd(). If -2 is |
3db935a9 DSH |
522 | returned then B<cmd> is not recognised and application specific arguments |
523 | can be checked instead. If -3 is returned a required argument is missing | |
524 | and an error is indicated. If 0 is returned some other error occurred and | |
525 | this can be reported back to the user. | |
526 | ||
7946ab33 | 527 | The function SSL_CONF_cmd_value_type() can be used by applications to |
ec2f7e56 DSH |
528 | check for the existence of a command or to perform additional syntax |
529 | checking or translation of the command value. For example if the return | |
530 | value is B<SSL_CONF_TYPE_FILE> an application could translate a relative | |
531 | pathname to an absolute pathname. | |
532 | ||
3db935a9 DSH |
533 | =head1 EXAMPLES |
534 | ||
535 | Set supported signature algorithms: | |
536 | ||
537 | SSL_CONF_cmd(ctx, "SignatureAlgorithms", "ECDSA+SHA256:RSA+SHA256:DSA+SHA256"); | |
538 | ||
24c2cd39 | 539 | There are various ways to select the supported protocols. |
7946ab33 KR |
540 | |
541 | This set the minimum protocol version to TLSv1, and so disables SSLv3. | |
542 | This is the recommended way to disable protocols. | |
543 | ||
544 | SSL_CONF_cmd(ctx, "MinProtocol", "TLSv1"); | |
545 | ||
546 | The following also disables SSLv3: | |
547 | ||
548 | SSL_CONF_cmd(ctx, "Protocol", "-SSLv3"); | |
549 | ||
57ce7b61 VD |
550 | The following will first enable all protocols, and then disable |
551 | SSLv3. | |
552 | If no protocol versions were disabled before this has the same effect as | |
553 | "-SSLv3", but if some versions were disables this will re-enable them before | |
554 | disabling SSLv3. | |
3db935a9 | 555 | |
87d9cafa | 556 | SSL_CONF_cmd(ctx, "Protocol", "ALL,-SSLv3"); |
3db935a9 DSH |
557 | |
558 | Only enable TLSv1.2: | |
559 | ||
7946ab33 KR |
560 | SSL_CONF_cmd(ctx, "MinProtocol", "TLSv1.2"); |
561 | SSL_CONF_cmd(ctx, "MaxProtocol", "TLSv1.2"); | |
562 | ||
563 | This also only enables TLSv1.2: | |
564 | ||
3db935a9 DSH |
565 | SSL_CONF_cmd(ctx, "Protocol", "-ALL,TLSv1.2"); |
566 | ||
567 | Disable TLS session tickets: | |
568 | ||
569 | SSL_CONF_cmd(ctx, "Options", "-SessionTicket"); | |
570 | ||
dc5744cb EK |
571 | Enable compression: |
572 | ||
573 | SSL_CONF_cmd(ctx, "Options", "Compression"); | |
574 | ||
3db935a9 DSH |
575 | Set supported curves to P-256, P-384: |
576 | ||
577 | SSL_CONF_cmd(ctx, "Curves", "P-256:P-384"); | |
578 | ||
579 | Set automatic support for any elliptic curve for key exchange: | |
580 | ||
581 | SSL_CONF_cmd(ctx, "ECDHParameters", "Automatic"); | |
582 | ||
583 | =head1 RETURN VALUES | |
584 | ||
4365e4aa | 585 | SSL_CONF_cmd() returns 1 if the value of B<cmd> is recognised and B<value> is |
3db935a9 DSH |
586 | B<NOT> used and 2 if both B<cmd> and B<value> are used. In other words it |
587 | returns the number of arguments processed. This is useful when processing | |
588 | command lines. | |
589 | ||
590 | A return value of -2 means B<cmd> is not recognised. | |
591 | ||
592 | A return value of -3 means B<cmd> is recognised and the command requires a | |
593 | value but B<value> is NULL. | |
594 | ||
595 | A return code of 0 indicates that both B<cmd> and B<value> are valid but an | |
596 | error occurred attempting to perform the operation: for example due to an | |
597 | error in the syntax of B<value> in this case the error queue may provide | |
598 | additional information. | |
599 | ||
600 | =head1 SEE ALSO | |
601 | ||
9b86974e RS |
602 | L<SSL_CONF_CTX_new(3)>, |
603 | L<SSL_CONF_CTX_set_flags(3)>, | |
604 | L<SSL_CONF_CTX_set1_prefix(3)>, | |
605 | L<SSL_CONF_CTX_set_ssl_ctx(3)>, | |
8106cb8b VD |
606 | L<SSL_CONF_cmd_argv(3)>, |
607 | L<SSL_CTX_set_options(3)> | |
3db935a9 DSH |
608 | |
609 | =head1 HISTORY | |
610 | ||
4365e4aa | 611 | SSL_CONF_cmd() was first added to OpenSSL 1.0.2 |
3db935a9 | 612 | |
57ce7b61 VD |
613 | B<SSL_OP_NO_SSL2> doesn't have effect since 1.1.0, but the macro is retained |
614 | for backwards compatibility. | |
45f55f6a | 615 | |
656b2605 DSH |
616 | B<SSL_CONF_TYPE_NONE> was first added to OpenSSL 1.1.0. In earlier versions of |
617 | OpenSSL passing a command which didn't take an argument would return | |
618 | B<SSL_CONF_TYPE_UNKNOWN>. | |
619 | ||
7946ab33 KR |
620 | B<MinProtocol> and B<MaxProtocol> where added in OpenSSL 1.1.0. |
621 | ||
e1c7871d TS |
622 | B<AllowNoDHEKEX> and B<PrioritizeChaCha> were added in OpenSSL 1.1.1. |
623 | ||
e2f92610 RS |
624 | =head1 COPYRIGHT |
625 | ||
e1c7871d | 626 | Copyright 2012-2017 The OpenSSL Project Authors. All Rights Reserved. |
e2f92610 RS |
627 | |
628 | Licensed under the OpenSSL license (the "License"). You may not use | |
629 | this file except in compliance with the License. You can obtain a copy | |
630 | in the file LICENSE in the source distribution or at | |
631 | L<https://www.openssl.org/source/license.html>. | |
632 | ||
633 | =cut |