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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 | ||
322755cc HK |
36 | This sets the supported signature algorithms for TLSv1.2 and TLSv1.3. |
37 | For clients this | |
13cfb043 DSH |
38 | value is used directly for the supported signature algorithms extension. For |
39 | servers it is used to determine which signature algorithms to support. | |
40 | ||
41 | The B<value> argument should be a colon separated list of signature algorithms | |
322755cc HK |
42 | in order of decreasing preference of the form B<algorithm+hash> or |
43 | B<signature_scheme>. B<algorithm> | |
13cfb043 DSH |
44 | is one of B<RSA>, B<DSA> or B<ECDSA> and B<hash> is a supported algorithm |
45 | OID short name such as B<SHA1>, B<SHA224>, B<SHA256>, B<SHA384> of B<SHA512>. | |
46 | Note: algorithm and hash names are case sensitive. | |
322755cc HK |
47 | B<signature_scheme> is one of the signature schemes defined in TLSv1.3, |
48 | specified using the IETF name, e.g., B<ecdsa_secp256r1_sha256>, B<ed25519>, | |
49 | or B<rsa_pss_pss_sha256>. | |
13cfb043 DSH |
50 | |
51 | If this option is not set then all signature algorithms supported by the | |
52 | OpenSSL library are permissible. | |
53 | ||
322755cc HK |
54 | Note: algorithms which specify a PKCS#1 v1.5 signature scheme (either by |
55 | using B<RSA> as the B<algorithm> or by using one of the B<rsa_pkcs1_*> | |
56 | identifiers) are ignored in TLSv1.3 and will not be negotiated. | |
57 | ||
13cfb043 DSH |
58 | =item B<-client_sigalgs> |
59 | ||
60 | This sets the supported signature algorithms associated with client | |
322755cc HK |
61 | authentication for TLSv1.2 and TLSv1.3. |
62 | For servers the value is used in the | |
63 | B<signature_algorithms> field of a B<CertificateRequest> message. | |
64 | For clients it is | |
65 | used to determine which signature algorithm to use with the client certificate. | |
13cfb043 DSH |
66 | If a server does not request a certificate this option has no effect. |
67 | ||
68 | The syntax of B<value> is identical to B<-sigalgs>. If not set then | |
69 | the value set for B<-sigalgs> will be used instead. | |
70 | ||
47f7cf05 MC |
71 | =item B<-groups> |
72 | ||
73 | This sets the supported groups. For clients, the groups are | |
74 | sent using the supported groups extension. For servers, it is used | |
322755cc HK |
75 | to determine which group to use. This setting affects groups used for |
76 | signatures (in TLSv1.2 and earlier) and key exchange. The first group listed | |
77 | will also be used for the B<key_share> sent by a client in a TLSv1.3 | |
78 | B<ClientHello>. | |
47f7cf05 MC |
79 | |
80 | The B<value> argument is a colon separated list of groups. The group can be | |
81 | either the B<NIST> name (e.g. B<P-256>), some other commonly used name where | |
dfa1f547 | 82 | applicable (e.g. B<X25519>, B<ffdhe2048>) or an OpenSSL OID name |
83 | (e.g B<prime256v1>). Group names are case sensitive. The list should be in | |
84 | order of preference with the most preferred group first. | |
85 | ||
86 | Currently supported groups for B<TLSv1.3> are B<P-256>, B<P-384>, B<P-521>, | |
87 | B<X25519>, B<X448>, B<ffdhe2048>, B<ffdhe3072>, B<ffdhe4096>, B<ffdhe6144>, | |
88 | B<ffdhe8192>. | |
47f7cf05 MC |
89 | |
90 | =item B<-curves> | |
91 | ||
92 | This is a synonym for the "-groups" command. | |
93 | ||
13cfb043 DSH |
94 | =item B<-named_curve> |
95 | ||
7946ab33 | 96 | This sets the temporary curve used for ephemeral ECDH modes. Only used by |
13cfb043 DSH |
97 | servers |
98 | ||
99 | The B<value> argument is a curve name or the special value B<auto> which | |
100 | picks an appropriate curve based on client and server preferences. The curve | |
101 | can be either the B<NIST> name (e.g. B<P-256>) or an OpenSSL OID name | |
102 | (e.g B<prime256v1>). Curve names are case sensitive. | |
103 | ||
104 | =item B<-cipher> | |
105 | ||
9d2674cd MC |
106 | Sets the TLSv1.2 and below ciphersuite list to B<value>. This list will be |
107 | combined with any configured TLSv1.3 ciphersuites. Note: syntax checking | |
108 | of B<value> is currently not performed unless a B<SSL> or B<SSL_CTX> structure is | |
13cfb043 DSH |
109 | associated with B<cctx>. |
110 | ||
9d2674cd MC |
111 | =item B<-ciphersuites> |
112 | ||
113 | Sets the available ciphersuites for TLSv1.3 to value. This is a simple colon | |
114 | (":") separated list of TLSv1.3 ciphersuite names in order of preference. This | |
115 | list will be combined any configured TLSv1.2 and below ciphersuites. | |
1903a9b7 | 116 | See L<openssl-ciphers(1)> for more information. |
9d2674cd MC |
117 | |
118 | ||
ec2f7e56 DSH |
119 | =item B<-cert> |
120 | ||
121 | Attempts to use the file B<value> as the certificate for the appropriate | |
fc1d88f0 RS |
122 | context. It currently uses SSL_CTX_use_certificate_chain_file() if an B<SSL_CTX> |
123 | structure is set or SSL_use_certificate_file() with filetype PEM if an B<SSL> | |
ec2f7e56 DSH |
124 | structure is set. This option is only supported if certificate operations |
125 | are permitted. | |
126 | ||
127 | =item B<-key> | |
128 | ||
129 | Attempts to use the file B<value> as the private key for the appropriate | |
130 | context. This option is only supported if certificate operations | |
131 | are permitted. Note: if no B<-key> option is set then a private key is | |
2011b169 | 132 | not loaded unless the flag B<SSL_CONF_FLAG_REQUIRE_PRIVATE> is set. |
ec2f7e56 | 133 | |
c557f921 DSH |
134 | =item B<-dhparam> |
135 | ||
136 | Attempts to use the file B<value> as the set of temporary DH parameters for | |
137 | the appropriate context. This option is only supported if certificate | |
138 | operations are permitted. | |
139 | ||
c649d10d TS |
140 | =item B<-record_padding> |
141 | ||
322755cc | 142 | Attempts to pad TLSv1.3 records so that they are a multiple of B<value> in |
c649d10d TS |
143 | length on send. A B<value> of 0 or 1 turns off padding. Otherwise, the |
144 | B<value> must be >1 or <=16384. | |
145 | ||
db0f35dd TS |
146 | =item B<-no_renegotiation> |
147 | ||
148 | Disables all attempts at renegotiation in TLSv1.2 and earlier, same as setting | |
149 | B<SSL_OP_NO_RENEGOTIATION>. | |
150 | ||
7946ab33 KR |
151 | =item B<-min_protocol>, B<-max_protocol> |
152 | ||
153 | Sets the minimum and maximum supported protocol. | |
57ce7b61 | 154 | Currently supported protocol values are B<SSLv3>, B<TLSv1>, |
322755cc | 155 | B<TLSv1.1>, B<TLSv1.2>, B<TLSv1.3> for TLS and B<DTLSv1>, B<DTLSv1.2> for DTLS, |
869e978c | 156 | and B<None> for no limit. |
322755cc | 157 | If either bound is not specified then only the other bound applies, |
57ce7b61 VD |
158 | if specified. |
159 | To restrict the supported protocol versions use these commands rather | |
160 | than the deprecated alternative commands below. | |
7946ab33 | 161 | |
582a17d6 | 162 | =item B<-no_ssl3>, B<-no_tls1>, B<-no_tls1_1>, B<-no_tls1_2>, B<-no_tls1_3> |
13cfb043 | 163 | |
582a17d6 MC |
164 | Disables protocol support for SSLv3, TLSv1.0, TLSv1.1, TLSv1.2 or TLSv1.3 by |
165 | setting the corresponding options B<SSL_OP_NO_SSLv3>, B<SSL_OP_NO_TLSv1>, | |
166 | B<SSL_OP_NO_TLSv1_1>, B<SSL_OP_NO_TLSv1_2> and B<SSL_OP_NO_TLSv1_3> | |
167 | respectively. These options are deprecated, instead use B<-min_protocol> and | |
168 | B<-max_protocol>. | |
13cfb043 DSH |
169 | |
170 | =item B<-bugs> | |
171 | ||
172 | Various bug workarounds are set, same as setting B<SSL_OP_ALL>. | |
173 | ||
dc5744cb | 174 | =item B<-comp> |
13cfb043 | 175 | |
cc5a9ba4 VD |
176 | Enables support for SSL/TLS compression, same as clearing |
177 | B<SSL_OP_NO_COMPRESSION>. | |
178 | This command was introduced in OpenSSL 1.1.0. | |
179 | As of OpenSSL 1.1.0, compression is off by default. | |
180 | ||
181 | =item B<-no_comp> | |
182 | ||
183 | Disables support for SSL/TLS compression, same as setting | |
184 | B<SSL_OP_NO_COMPRESSION>. | |
185 | As of OpenSSL 1.1.0, compression is off by default. | |
13cfb043 DSH |
186 | |
187 | =item B<-no_ticket> | |
188 | ||
189 | Disables support for session tickets, same as setting B<SSL_OP_NO_TICKET>. | |
190 | ||
191 | =item B<-serverpref> | |
192 | ||
193 | Use server and not client preference order when determining which cipher suite, | |
194 | signature algorithm or elliptic curve to use for an incoming connection. | |
195 | Equivalent to B<SSL_OP_CIPHER_SERVER_PREFERENCE>. Only used by servers. | |
196 | ||
e1c7871d TS |
197 | =item B<-prioritize_chacha> |
198 | ||
199 | Prioritize ChaCha ciphers when the client has a ChaCha20 cipher at the top of | |
200 | its preference list. This usually indicates a client without AES hardware | |
201 | acceleration (e.g. mobile) is in use. Equivalent to B<SSL_OP_PRIORITIZE_CHACHA>. | |
202 | Only used by servers. Requires B<-serverpref>. | |
203 | ||
f0ef019d DSH |
204 | =item B<-no_resumption_on_reneg> |
205 | ||
206 | set SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION flag. Only used by servers. | |
207 | ||
13cfb043 DSH |
208 | =item B<-legacyrenegotiation> |
209 | ||
210 | permits the use of unsafe legacy renegotiation. Equivalent to setting | |
211 | B<SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION>. | |
212 | ||
213 | =item B<-legacy_server_connect>, B<-no_legacy_server_connect> | |
214 | ||
215 | permits or prohibits the use of unsafe legacy renegotiation for OpenSSL | |
216 | clients only. Equivalent to setting or clearing B<SSL_OP_LEGACY_SERVER_CONNECT>. | |
217 | Set by default. | |
218 | ||
4e2bd9cb MC |
219 | =item B<-allow_no_dhe_kex> |
220 | ||
221 | In TLSv1.3 allow a non-(ec)dhe based key exchange mode on resumption. This means | |
222 | that there will be no forward secrecy for the resumed session. | |
223 | ||
13cfb043 DSH |
224 | =item B<-strict> |
225 | ||
226 | enables strict mode protocol handling. Equivalent to setting | |
227 | B<SSL_CERT_FLAG_TLS_STRICT>. | |
228 | ||
3bb5e5b0 MC |
229 | =item B<-anti_replay>, B<-no_anti_replay> |
230 | ||
231 | Switches replay protection, on or off respectively. With replay protection on, | |
232 | OpenSSL will automatically detect if a session ticket has been used more than | |
233 | once, TLSv1.3 has been negotiated, and early data is enabled on the server. A | |
234 | full handshake is forced if a session ticket is used a second or subsequent | |
235 | time. Anti-Replay is on by default unless overridden by a configuration file and | |
236 | is only used by servers. Anti-replay measures are required for compliance with | |
237 | the TLSv1.3 specification. Some applications may be able to mitigate the replay | |
238 | risks in other ways and in such cases the built-in OpenSSL functionality is not | |
239 | required. Switching off anti-replay is equivalent to B<SSL_OP_NO_ANTI_REPLAY>. | |
240 | ||
13cfb043 | 241 | =back |
3db935a9 DSH |
242 | |
243 | =head1 SUPPORTED CONFIGURATION FILE COMMANDS | |
244 | ||
245 | Currently supported B<cmd> names for configuration files (i.e. when the | |
246 | flag B<SSL_CONF_FLAG_FILE> is set) are listed below. All configuration file | |
854dfcd8 | 247 | B<cmd> names are case insensitive so B<signaturealgorithms> is recognised |
c7b7984a | 248 | as well as B<SignatureAlgorithms>. Unless otherwise stated the B<value> names |
3db935a9 DSH |
249 | are also case insensitive. |
250 | ||
251 | Note: the command prefix (if set) alters the recognised B<cmd> values. | |
252 | ||
253 | =over 4 | |
254 | ||
65f2a565 | 255 | =item B<CipherString> |
3db935a9 | 256 | |
9d2674cd MC |
257 | Sets the ciphersuite list for TLSv1.2 and below to B<value>. This list will be |
258 | combined with any configured TLSv1.3 ciphersuites. Note: syntax | |
259 | checking of B<value> is currently not performed unless an B<SSL> or B<SSL_CTX> | |
260 | structure is associated with B<cctx>. | |
261 | ||
262 | =item B<Ciphersuites> | |
263 | ||
264 | Sets the available ciphersuites for TLSv1.3 to B<value>. This is a simple colon | |
265 | (":") separated list of TLSv1.3 ciphersuite names in order of preference. This | |
266 | list will be combined any configured TLSv1.2 and below ciphersuites. | |
1903a9b7 | 267 | See L<openssl-ciphers(1)> for more information. |
3db935a9 | 268 | |
ec2f7e56 DSH |
269 | =item B<Certificate> |
270 | ||
271 | Attempts to use the file B<value> as the certificate for the appropriate | |
fc1d88f0 RS |
272 | context. It currently uses SSL_CTX_use_certificate_chain_file() if an B<SSL_CTX> |
273 | structure is set or SSL_use_certificate_file() with filetype PEM if an B<SSL> | |
ec2f7e56 DSH |
274 | structure is set. This option is only supported if certificate operations |
275 | are permitted. | |
276 | ||
277 | =item B<PrivateKey> | |
278 | ||
279 | Attempts to use the file B<value> as the private key for the appropriate | |
280 | context. This option is only supported if certificate operations | |
2011b169 DSH |
281 | are permitted. Note: if no B<PrivateKey> option is set then a private key is |
282 | not loaded unless the B<SSL_CONF_FLAG_REQUIRE_PRIVATE> is set. | |
ec2f7e56 | 283 | |
429261d0 DSH |
284 | =item B<ChainCAFile>, B<ChainCAPath>, B<VerifyCAFile>, B<VerifyCAPath> |
285 | ||
286 | These options indicate a file or directory used for building certificate | |
287 | chains or verifying certificate chains. These options are only supported | |
288 | if certificate operations are permitted. | |
289 | ||
5a185729 DSH |
290 | =item B<RequestCAFile> |
291 | ||
292 | This option indicates a file containing a set of certificates in PEM form. | |
293 | The subject names of the certificates are sent to the peer in the | |
294 | B<certificate_authorities> extension for TLS 1.3 (in ClientHello or | |
295 | CertificateRequest) or in a certificate request for previous versions or | |
296 | TLS. | |
297 | ||
5b7f36e8 DSH |
298 | =item B<ServerInfoFile> |
299 | ||
300 | Attempts to use the file B<value> in the "serverinfo" extension using the | |
301 | function SSL_CTX_use_serverinfo_file. | |
302 | ||
c557f921 DSH |
303 | =item B<DHParameters> |
304 | ||
305 | Attempts to use the file B<value> as the set of temporary DH parameters for | |
306 | the appropriate context. This option is only supported if certificate | |
307 | operations are permitted. | |
308 | ||
c649d10d TS |
309 | =item B<RecordPadding> |
310 | ||
322755cc | 311 | Attempts to pad TLSv1.3 records so that they are a multiple of B<value> in |
c649d10d TS |
312 | length on send. A B<value> of 0 or 1 turns off padding. Otherwise, the |
313 | B<value> must be >1 or <=16384. | |
314 | ||
3db935a9 DSH |
315 | =item B<SignatureAlgorithms> |
316 | ||
322755cc HK |
317 | This sets the supported signature algorithms for TLSv1.2 and TLSv1.3. |
318 | For clients this | |
3db935a9 DSH |
319 | value is used directly for the supported signature algorithms extension. For |
320 | servers it is used to determine which signature algorithms to support. | |
321 | ||
322 | The B<value> argument should be a colon separated list of signature algorithms | |
322755cc HK |
323 | in order of decreasing preference of the form B<algorithm+hash> or |
324 | B<signature_scheme>. B<algorithm> | |
3db935a9 DSH |
325 | is one of B<RSA>, B<DSA> or B<ECDSA> and B<hash> is a supported algorithm |
326 | OID short name such as B<SHA1>, B<SHA224>, B<SHA256>, B<SHA384> of B<SHA512>. | |
327 | Note: algorithm and hash names are case sensitive. | |
322755cc HK |
328 | B<signature_scheme> is one of the signature schemes defined in TLSv1.3, |
329 | specified using the IETF name, e.g., B<ecdsa_secp256r1_sha256>, B<ed25519>, | |
330 | or B<rsa_pss_pss_sha256>. | |
3db935a9 DSH |
331 | |
332 | If this option is not set then all signature algorithms supported by the | |
333 | OpenSSL library are permissible. | |
334 | ||
322755cc HK |
335 | Note: algorithms which specify a PKCS#1 v1.5 signature scheme (either by |
336 | using B<RSA> as the B<algorithm> or by using one of the B<rsa_pkcs1_*> | |
337 | identifiers) are ignored in TLSv1.3 and will not be negotiated. | |
338 | ||
3db935a9 DSH |
339 | =item B<ClientSignatureAlgorithms> |
340 | ||
341 | This sets the supported signature algorithms associated with client | |
322755cc HK |
342 | authentication for TLSv1.2 and TLSv1.3. |
343 | For servers the value is used in the | |
344 | B<signature_algorithms> field of a B<CertificateRequest> message. | |
345 | For clients it is | |
346 | used to determine which signature algorithm to use with the client certificate. | |
347 | If a server does not request a certificate this option has no effect. | |
3db935a9 DSH |
348 | |
349 | The syntax of B<value> is identical to B<SignatureAlgorithms>. If not set then | |
350 | the value set for B<SignatureAlgorithms> will be used instead. | |
351 | ||
47f7cf05 | 352 | =item B<Groups> |
3db935a9 | 353 | |
47f7cf05 MC |
354 | This sets the supported groups. For clients, the groups are |
355 | sent using the supported groups extension. For servers, it is used | |
322755cc HK |
356 | to determine which group to use. This setting affects groups used for |
357 | signatures (in TLSv1.2 and earlier) and key exchange. The first group listed | |
358 | will also be used for the B<key_share> sent by a client in a TLSv1.3 | |
359 | B<ClientHello>. | |
3db935a9 | 360 | |
47f7cf05 MC |
361 | The B<value> argument is a colon separated list of groups. The group can be |
362 | either the B<NIST> name (e.g. B<P-256>), some other commonly used name where | |
dfa1f547 | 363 | applicable (e.g. B<X25519>, B<ffdhe2048>) or an OpenSSL OID name |
364 | (e.g B<prime256v1>). Group names are case sensitive. The list should be in | |
365 | order of preference with the most preferred group first. | |
366 | ||
367 | Currently supported groups for B<TLSv1.3> are B<P-256>, B<P-384>, B<P-521>, | |
368 | B<X25519>, B<X448>, B<ffdhe2048>, B<ffdhe3072>, B<ffdhe4096>, B<ffdhe6144>, | |
369 | B<ffdhe8192>. | |
47f7cf05 MC |
370 | |
371 | =item B<Curves> | |
372 | ||
373 | This is a synonym for the "Groups" command. | |
3db935a9 | 374 | |
7946ab33 KR |
375 | =item B<MinProtocol> |
376 | ||
377 | This sets the minimum supported SSL, TLS or DTLS version. | |
378 | ||
57ce7b61 | 379 | Currently supported protocol values are B<SSLv3>, B<TLSv1>, B<TLSv1.1>, |
322755cc | 380 | B<TLSv1.2>, B<TLSv1.3>, B<DTLSv1> and B<DTLSv1.2>. |
869e978c | 381 | The value B<None> will disable the limit. |
7946ab33 KR |
382 | |
383 | =item B<MaxProtocol> | |
384 | ||
385 | This sets the maximum supported SSL, TLS or DTLS version. | |
386 | ||
57ce7b61 | 387 | Currently supported protocol values are B<SSLv3>, B<TLSv1>, B<TLSv1.1>, |
322755cc | 388 | B<TLSv1.2>, B<TLSv1.3>, B<DTLSv1> and B<DTLSv1.2>. |
869e978c | 389 | The value B<None> will disable the limit. |
7946ab33 | 390 | |
3db935a9 DSH |
391 | =item B<Protocol> |
392 | ||
57ce7b61 VD |
393 | This can be used to enable or disable certain versions of the SSL, |
394 | TLS or DTLS protocol. | |
7946ab33 | 395 | |
57ce7b61 VD |
396 | The B<value> argument is a comma separated list of supported protocols |
397 | to enable or disable. | |
7946ab33 KR |
398 | If a protocol is preceded by B<-> that version is disabled. |
399 | ||
400 | All protocol versions are enabled by default. | |
57ce7b61 VD |
401 | You need to disable at least one protocol version for this setting have any |
402 | effect. | |
403 | Only enabling some protocol versions does not disable the other protocol | |
404 | versions. | |
7946ab33 | 405 | |
57ce7b61 | 406 | Currently supported protocol values are B<SSLv3>, B<TLSv1>, B<TLSv1.1>, |
322755cc | 407 | B<TLSv1.2>, B<TLSv1.3>, B<DTLSv1> and B<DTLSv1.2>. |
7946ab33 | 408 | The special value B<ALL> refers to all supported versions. |
3db935a9 | 409 | |
57ce7b61 VD |
410 | This can't enable protocols that are disabled using B<MinProtocol> |
411 | or B<MaxProtocol>, but can disable protocols that are still allowed | |
412 | by them. | |
7946ab33 KR |
413 | |
414 | The B<Protocol> command is fragile and deprecated; do not use it. | |
415 | Use B<MinProtocol> and B<MaxProtocol> instead. | |
57ce7b61 VD |
416 | If you do use B<Protocol>, make sure that the resulting range of enabled |
417 | protocols has no "holes", e.g. if TLS 1.0 and TLS 1.2 are both enabled, make | |
418 | sure to also leave TLS 1.1 enabled. | |
3db935a9 DSH |
419 | |
420 | =item B<Options> | |
421 | ||
422 | The B<value> argument is a comma separated list of various flags to set. | |
8106cb8b VD |
423 | If a flag string is preceded B<-> it is disabled. |
424 | See the L<SSL_CTX_set_options(3)> function for more details of | |
425 | individual options. | |
3db935a9 DSH |
426 | |
427 | Each option is listed below. Where an operation is enabled by default | |
428 | the B<-flag> syntax is needed to disable it. | |
429 | ||
430 | B<SessionTicket>: session ticket support, enabled by default. Inverse of | |
431 | B<SSL_OP_NO_TICKET>: that is B<-SessionTicket> is the same as setting | |
432 | B<SSL_OP_NO_TICKET>. | |
433 | ||
434 | B<Compression>: SSL/TLS compression support, enabled by default. Inverse | |
435 | of B<SSL_OP_NO_COMPRESSION>. | |
436 | ||
437 | B<EmptyFragments>: use empty fragments as a countermeasure against a | |
438 | SSL 3.0/TLS 1.0 protocol vulnerability affecting CBC ciphers. It | |
439 | is set by default. Inverse of B<SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS>. | |
440 | ||
c7b7984a | 441 | B<Bugs>: enable various bug workarounds. Same as B<SSL_OP_ALL>. |
3db935a9 | 442 | |
c7b7984a | 443 | B<DHSingle>: enable single use DH keys, set by default. Inverse of |
3db935a9 DSH |
444 | B<SSL_OP_DH_SINGLE>. Only used by servers. |
445 | ||
e1c7871d | 446 | B<ECDHSingle>: enable single use ECDH keys, set by default. Inverse of |
3db935a9 DSH |
447 | B<SSL_OP_ECDH_SINGLE>. Only used by servers. |
448 | ||
e1c7871d | 449 | B<ServerPreference>: use server and not client preference order when |
3db935a9 DSH |
450 | determining which cipher suite, signature algorithm or elliptic curve |
451 | to use for an incoming connection. Equivalent to | |
452 | B<SSL_OP_CIPHER_SERVER_PREFERENCE>. Only used by servers. | |
453 | ||
e1c7871d TS |
454 | B<PrioritizeChaCha>: prioritizes ChaCha ciphers when the client has a |
455 | ChaCha20 cipher at the top of its preference list. This usually indicates | |
456 | a mobile client is in use. Equivalent to B<SSL_OP_PRIORITIZE_CHACHA>. | |
457 | Only used by servers. | |
458 | ||
459 | B<NoResumptionOnRenegotiation>: set | |
f0ef019d DSH |
460 | B<SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION> flag. Only used by servers. |
461 | ||
4ac5e43d HK |
462 | B<NoRenegotiation>: disables all attempts at renegotiation in TLSv1.2 and |
463 | earlier, same as setting B<SSL_OP_NO_RENEGOTIATION>. | |
464 | ||
e1c7871d | 465 | B<UnsafeLegacyRenegotiation>: permits the use of unsafe legacy renegotiation. |
3db935a9 DSH |
466 | Equivalent to B<SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION>. |
467 | ||
e1c7871d | 468 | B<UnsafeLegacyServerConnect>: permits the use of unsafe legacy renegotiation |
3db935a9 DSH |
469 | for OpenSSL clients only. Equivalent to B<SSL_OP_LEGACY_SERVER_CONNECT>. |
470 | Set by default. | |
471 | ||
b3618f44 EK |
472 | B<EncryptThenMac>: use encrypt-then-mac extension, enabled by |
473 | default. Inverse of B<SSL_OP_NO_ENCRYPT_THEN_MAC>: that is, | |
474 | B<-EncryptThenMac> is the same as setting B<SSL_OP_NO_ENCRYPT_THEN_MAC>. | |
4e2bd9cb MC |
475 | |
476 | B<AllowNoDHEKEX>: In TLSv1.3 allow a non-(ec)dhe based key exchange mode on | |
477 | resumption. This means that there will be no forward secrecy for the resumed | |
478 | session. Equivalent to B<SSL_OP_ALLOW_NO_DHE_KEX>. | |
b3618f44 | 479 | |
1c4b1545 MC |
480 | B<MiddleboxCompat>: If set then dummy Change Cipher Spec (CCS) messages are sent |
481 | in TLSv1.3. This has the effect of making TLSv1.3 look more like TLSv1.2 so that | |
482 | middleboxes that do not understand TLSv1.3 will not drop the connection. This | |
483 | option is set by default. A future version of OpenSSL may not set this by | |
484 | default. Equivalent to B<SSL_OP_ENABLE_MIDDLEBOX_COMPAT>. | |
485 | ||
3bb5e5b0 MC |
486 | B<AntiReplay>: If set then OpenSSL will automatically detect if a session ticket |
487 | has been used more than once, TLSv1.3 has been negotiated, and early data is | |
488 | enabled on the server. A full handshake is forced if a session ticket is used a | |
489 | second or subsequent time. This option is set by default and is only used by | |
490 | servers. Anti-replay measures are required to comply with the TLSv1.3 | |
491 | specification. Some applications may be able to mitigate the replay risks in | |
492 | other ways and in such cases the built-in OpenSSL functionality is not required. | |
493 | Disabling anti-replay is equivalent to setting B<SSL_OP_NO_ANTI_REPLAY>. | |
494 | ||
088dfa13 TS |
495 | B<ExtendedMasterSecret>: use extended master secret extension, enabled by |
496 | default. Inverse of B<SSL_OP_NO_EXTENDED_MASTER_SECRET>: that is, | |
497 | B<-ExtendedMasterSecret> is the same as setting B<SSL_OP_NO_EXTENDED_MASTER_SECRET>. | |
498 | ||
429261d0 DSH |
499 | =item B<VerifyMode> |
500 | ||
501 | The B<value> argument is a comma separated list of flags to set. | |
502 | ||
503 | B<Peer> enables peer verification: for clients only. | |
504 | ||
505 | B<Request> requests but does not require a certificate from the client. | |
506 | Servers only. | |
507 | ||
508 | B<Require> requests and requires a certificate from the client: an error | |
509 | occurs if the client does not present a certificate. Servers only. | |
510 | ||
511 | B<Once> requests a certificate from a client only on the initial connection: | |
512 | not when renegotiating. Servers only. | |
513 | ||
9d75dce3 TS |
514 | B<RequestPostHandshake> configures the connection to support requests but does |
515 | not require a certificate from the client post-handshake. A certificate will | |
516 | not be requested during the initial handshake. The server application must | |
517 | provide a mechanism to request a certificate post-handshake. Servers only. | |
518 | TLSv1.3 only. | |
519 | ||
520 | B<RequiresPostHandshake> configures the connection to support requests and | |
521 | requires a certificate from the client post-handshake: an error occurs if the | |
522 | client does not present a certificate. A certificate will not be requested | |
523 | during the initial handshake. The server application must provide a mechanism | |
524 | to request a certificate post-handshake. Servers only. TLSv1.3 only. | |
525 | ||
429261d0 DSH |
526 | =item B<ClientCAFile>, B<ClientCAPath> |
527 | ||
528 | A file or directory of certificates in PEM format whose names are used as the | |
529 | set of acceptable names for client CAs. Servers only. This option is only | |
530 | supported if certificate operations are permitted. | |
531 | ||
3db935a9 DSH |
532 | =back |
533 | ||
ec2f7e56 DSH |
534 | =head1 SUPPORTED COMMAND TYPES |
535 | ||
536 | The function SSL_CONF_cmd_value_type() currently returns one of the following | |
537 | types: | |
538 | ||
539 | =over 4 | |
540 | ||
541 | =item B<SSL_CONF_TYPE_UNKNOWN> | |
542 | ||
543 | The B<cmd> string is unrecognised, this return value can be use to flag | |
544 | syntax errors. | |
545 | ||
546 | =item B<SSL_CONF_TYPE_STRING> | |
547 | ||
548 | The value is a string without any specific structure. | |
549 | ||
550 | =item B<SSL_CONF_TYPE_FILE> | |
551 | ||
9c0586d5 | 552 | The value is a filename. |
ec2f7e56 DSH |
553 | |
554 | =item B<SSL_CONF_TYPE_DIR> | |
555 | ||
556 | The value is a directory name. | |
557 | ||
656b2605 DSH |
558 | =item B<SSL_CONF_TYPE_NONE> |
559 | ||
560 | The value string is not used e.g. a command line option which doesn't take an | |
561 | argument. | |
562 | ||
fa9d77dc CR |
563 | =back |
564 | ||
3db935a9 DSH |
565 | =head1 NOTES |
566 | ||
567 | The order of operations is significant. This can be used to set either defaults | |
568 | or values which cannot be overridden. For example if an application calls: | |
569 | ||
87d9cafa | 570 | SSL_CONF_cmd(ctx, "Protocol", "-SSLv3"); |
3db935a9 DSH |
571 | SSL_CONF_cmd(ctx, userparam, uservalue); |
572 | ||
87d9cafa | 573 | it will disable SSLv3 support by default but the user can override it. If |
3db935a9 DSH |
574 | however the call sequence is: |
575 | ||
576 | SSL_CONF_cmd(ctx, userparam, uservalue); | |
87d9cafa | 577 | SSL_CONF_cmd(ctx, "Protocol", "-SSLv3"); |
3db935a9 | 578 | |
87d9cafa | 579 | SSLv3 is B<always> disabled and attempt to override this by the user are |
3db935a9 DSH |
580 | ignored. |
581 | ||
f5f85f75 | 582 | By checking the return code of SSL_CONF_cmd() it is possible to query if a |
44e69951 | 583 | given B<cmd> is recognised, this is useful if SSL_CONF_cmd() values are |
3db935a9 DSH |
584 | mixed with additional application specific operations. |
585 | ||
f5f85f75 | 586 | For example an application might call SSL_CONF_cmd() and if it returns |
3db935a9 DSH |
587 | -2 (unrecognised command) continue with processing of application specific |
588 | commands. | |
589 | ||
f5f85f75 JS |
590 | Applications can also use SSL_CONF_cmd() to process command lines though the |
591 | utility function SSL_CONF_cmd_argv() is normally used instead. One way | |
821244cf DSH |
592 | to do this is to set the prefix to an appropriate value using |
593 | SSL_CONF_CTX_set1_prefix(), pass the current argument to B<cmd> and the | |
594 | following argument to B<value> (which may be NULL). | |
3db935a9 DSH |
595 | |
596 | In this case if the return value is positive then it is used to skip that | |
f5f85f75 | 597 | number of arguments as they have been processed by SSL_CONF_cmd(). If -2 is |
3db935a9 DSH |
598 | returned then B<cmd> is not recognised and application specific arguments |
599 | can be checked instead. If -3 is returned a required argument is missing | |
600 | and an error is indicated. If 0 is returned some other error occurred and | |
601 | this can be reported back to the user. | |
602 | ||
7946ab33 | 603 | The function SSL_CONF_cmd_value_type() can be used by applications to |
ec2f7e56 DSH |
604 | check for the existence of a command or to perform additional syntax |
605 | checking or translation of the command value. For example if the return | |
606 | value is B<SSL_CONF_TYPE_FILE> an application could translate a relative | |
607 | pathname to an absolute pathname. | |
608 | ||
4564e77a PY |
609 | =head1 RETURN VALUES |
610 | ||
611 | SSL_CONF_cmd() returns 1 if the value of B<cmd> is recognised and B<value> is | |
612 | B<NOT> used and 2 if both B<cmd> and B<value> are used. In other words it | |
613 | returns the number of arguments processed. This is useful when processing | |
614 | command lines. | |
615 | ||
616 | A return value of -2 means B<cmd> is not recognised. | |
617 | ||
618 | A return value of -3 means B<cmd> is recognised and the command requires a | |
619 | value but B<value> is NULL. | |
620 | ||
621 | A return code of 0 indicates that both B<cmd> and B<value> are valid but an | |
622 | error occurred attempting to perform the operation: for example due to an | |
623 | error in the syntax of B<value> in this case the error queue may provide | |
624 | additional information. | |
625 | ||
3db935a9 DSH |
626 | =head1 EXAMPLES |
627 | ||
628 | Set supported signature algorithms: | |
629 | ||
630 | SSL_CONF_cmd(ctx, "SignatureAlgorithms", "ECDSA+SHA256:RSA+SHA256:DSA+SHA256"); | |
631 | ||
24c2cd39 | 632 | There are various ways to select the supported protocols. |
7946ab33 KR |
633 | |
634 | This set the minimum protocol version to TLSv1, and so disables SSLv3. | |
635 | This is the recommended way to disable protocols. | |
636 | ||
637 | SSL_CONF_cmd(ctx, "MinProtocol", "TLSv1"); | |
638 | ||
639 | The following also disables SSLv3: | |
640 | ||
641 | SSL_CONF_cmd(ctx, "Protocol", "-SSLv3"); | |
642 | ||
57ce7b61 VD |
643 | The following will first enable all protocols, and then disable |
644 | SSLv3. | |
645 | If no protocol versions were disabled before this has the same effect as | |
646 | "-SSLv3", but if some versions were disables this will re-enable them before | |
647 | disabling SSLv3. | |
3db935a9 | 648 | |
87d9cafa | 649 | SSL_CONF_cmd(ctx, "Protocol", "ALL,-SSLv3"); |
3db935a9 DSH |
650 | |
651 | Only enable TLSv1.2: | |
652 | ||
7946ab33 KR |
653 | SSL_CONF_cmd(ctx, "MinProtocol", "TLSv1.2"); |
654 | SSL_CONF_cmd(ctx, "MaxProtocol", "TLSv1.2"); | |
655 | ||
656 | This also only enables TLSv1.2: | |
657 | ||
3db935a9 DSH |
658 | SSL_CONF_cmd(ctx, "Protocol", "-ALL,TLSv1.2"); |
659 | ||
660 | Disable TLS session tickets: | |
661 | ||
662 | SSL_CONF_cmd(ctx, "Options", "-SessionTicket"); | |
663 | ||
dc5744cb EK |
664 | Enable compression: |
665 | ||
666 | SSL_CONF_cmd(ctx, "Options", "Compression"); | |
667 | ||
3db935a9 DSH |
668 | Set supported curves to P-256, P-384: |
669 | ||
670 | SSL_CONF_cmd(ctx, "Curves", "P-256:P-384"); | |
671 | ||
3db935a9 DSH |
672 | =head1 SEE ALSO |
673 | ||
98ca37e4 | 674 | L<ssl(7)>, |
9b86974e RS |
675 | L<SSL_CONF_CTX_new(3)>, |
676 | L<SSL_CONF_CTX_set_flags(3)>, | |
677 | L<SSL_CONF_CTX_set1_prefix(3)>, | |
678 | L<SSL_CONF_CTX_set_ssl_ctx(3)>, | |
8106cb8b VD |
679 | L<SSL_CONF_cmd_argv(3)>, |
680 | L<SSL_CTX_set_options(3)> | |
3db935a9 DSH |
681 | |
682 | =head1 HISTORY | |
683 | ||
fc5ecadd | 684 | The SSL_CONF_cmd() function was added in OpenSSL 1.0.2. |
3db935a9 | 685 | |
fc5ecadd DMSP |
686 | The B<SSL_OP_NO_SSL2> option doesn't have effect since 1.1.0, but the macro |
687 | is retained for backwards compatibility. | |
45f55f6a | 688 | |
fc5ecadd | 689 | The B<SSL_CONF_TYPE_NONE> was added in OpenSSL 1.1.0. In earlier versions of |
656b2605 DSH |
690 | OpenSSL passing a command which didn't take an argument would return |
691 | B<SSL_CONF_TYPE_UNKNOWN>. | |
692 | ||
7946ab33 KR |
693 | B<MinProtocol> and B<MaxProtocol> where added in OpenSSL 1.1.0. |
694 | ||
e1c7871d TS |
695 | B<AllowNoDHEKEX> and B<PrioritizeChaCha> were added in OpenSSL 1.1.1. |
696 | ||
e2f92610 RS |
697 | =head1 COPYRIGHT |
698 | ||
6738bf14 | 699 | Copyright 2012-2018 The OpenSSL Project Authors. All Rights Reserved. |
e2f92610 | 700 | |
4746f25a | 701 | Licensed under the Apache License 2.0 (the "License"). You may not use |
e2f92610 RS |
702 | this file except in compliance with the License. You can obtain a copy |
703 | in the file LICENSE in the source distribution or at | |
704 | L<https://www.openssl.org/source/license.html>. | |
705 | ||
706 | =cut |