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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 | ||
8b3efb53 RS |
12 | int SSL_CONF_cmd(SSL_CONF_CTX *ctx, const char *option, const char *value); |
13 | int SSL_CONF_cmd_value_type(SSL_CONF_CTX *ctx, const char *option); | |
3db935a9 DSH |
14 | |
15 | =head1 DESCRIPTION | |
16 | ||
8b3efb53 | 17 | The function SSL_CONF_cmd() performs configuration operation B<option> with |
3db935a9 DSH |
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 | ||
8b3efb53 | 22 | SSL_CONF_cmd_value_type() returns the type of value that B<option> refers to. |
ec2f7e56 | 23 | |
13cfb043 DSH |
24 | =head1 SUPPORTED COMMAND LINE COMMANDS |
25 | ||
8b3efb53 | 26 | Currently supported B<option> names for command lines (i.e. when the |
6c014da0 TC |
27 | flag B<SSL_CONF_FLAG_CMDLINE> is set) are listed below. Note: all B<option> |
28 | names 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 | ||
8b3efb53 | 34 | =item B<-bugs> |
13cfb043 | 35 | |
8b3efb53 | 36 | Various bug workarounds are set, same as setting B<SSL_OP_ALL>. |
13cfb043 | 37 | |
8b3efb53 | 38 | =item B<-no_comp> |
13cfb043 | 39 | |
8b3efb53 RS |
40 | Disables support for SSL/TLS compression, same as setting |
41 | B<SSL_OP_NO_COMPRESSION>. | |
42 | As of OpenSSL 1.1.0, compression is off by default. | |
13cfb043 | 43 | |
8b3efb53 | 44 | =item B<-comp> |
322755cc | 45 | |
8b3efb53 RS |
46 | Enables support for SSL/TLS compression, same as clearing |
47 | B<SSL_OP_NO_COMPRESSION>. | |
48 | This command was introduced in OpenSSL 1.1.0. | |
49 | As of OpenSSL 1.1.0, compression is off by default. | |
13cfb043 | 50 | |
8b3efb53 | 51 | =item B<-no_ticket> |
13cfb043 | 52 | |
8b3efb53 | 53 | Disables support for session tickets, same as setting B<SSL_OP_NO_TICKET>. |
13cfb043 | 54 | |
8b3efb53 | 55 | =item B<-serverpref> |
47f7cf05 | 56 | |
8b3efb53 RS |
57 | Use server and not client preference order when determining which cipher suite, |
58 | signature algorithm or elliptic curve to use for an incoming connection. | |
59 | Equivalent to B<SSL_OP_CIPHER_SERVER_PREFERENCE>. Only used by servers. | |
47f7cf05 | 60 | |
55373bfd RS |
61 | =item B<-client_renegotiation> |
62 | ||
63 | Allows servers to accept client-initiated renegotiation. Equivalent to | |
64 | setting B<SSL_OP_ALLOW_CLIENT_RENEGOTIATION>. | |
65 | Only used by servers. | |
66 | ||
8b3efb53 | 67 | =item B<-legacyrenegotiation> |
dfa1f547 | 68 | |
55373bfd | 69 | Permits the use of unsafe legacy renegotiation. Equivalent to setting |
8b3efb53 | 70 | B<SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION>. |
47f7cf05 | 71 | |
8b3efb53 | 72 | =item B<-no_renegotiation> |
47f7cf05 | 73 | |
8b3efb53 RS |
74 | Disables all attempts at renegotiation in TLSv1.2 and earlier, same as setting |
75 | B<SSL_OP_NO_RENEGOTIATION>. | |
47f7cf05 | 76 | |
8b3efb53 | 77 | =item B<-no_resumption_on_reneg> |
13cfb043 | 78 | |
55373bfd | 79 | Sets B<SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION>. Only used by servers. |
13cfb043 | 80 | |
8b3efb53 | 81 | =item B<-legacy_server_connect>, B<-no_legacy_server_connect> |
13cfb043 | 82 | |
55373bfd | 83 | Permits or prohibits the use of unsafe legacy renegotiation for OpenSSL |
8b3efb53 | 84 | clients only. Equivalent to setting or clearing B<SSL_OP_LEGACY_SERVER_CONNECT>. |
13cfb043 | 85 | |
55373bfd RS |
86 | =item B<-immediate_renegotiation> |
87 | ||
88 | Try to do a renegotiation immediately after the handshake. | |
89 | This is for debugging and has no option equivalent. | |
90 | Ignored by the B<openssl s_client> command. | |
91 | ||
8b3efb53 | 92 | =item B<-prioritize_chacha> |
13cfb043 | 93 | |
8b3efb53 RS |
94 | Prioritize ChaCha ciphers when the client has a ChaCha20 cipher at the top of |
95 | its preference list. This usually indicates a client without AES hardware | |
96 | acceleration (e.g. mobile) is in use. Equivalent to B<SSL_OP_PRIORITIZE_CHACHA>. | |
97 | Only used by servers. Requires B<-serverpref>. | |
9d2674cd | 98 | |
8b3efb53 | 99 | =item B<-allow_no_dhe_kex> |
9d2674cd | 100 | |
8b3efb53 RS |
101 | In TLSv1.3 allow a non-(ec)dhe based key exchange mode on resumption. This means |
102 | that there will be no forward secrecy for the resumed session. | |
9d2674cd | 103 | |
8b3efb53 | 104 | =item B<-strict> |
ec2f7e56 | 105 | |
55373bfd | 106 | Enables strict mode protocol handling. Equivalent to setting |
8b3efb53 | 107 | B<SSL_CERT_FLAG_TLS_STRICT>. |
ec2f7e56 | 108 | |
8b3efb53 | 109 | =item B<-sigalgs> I<algs> |
ec2f7e56 | 110 | |
8b3efb53 RS |
111 | This sets the supported signature algorithms for TLSv1.2 and TLSv1.3. |
112 | For clients this value is used directly for the supported signature | |
113 | algorithms extension. For servers it is used to determine which signature | |
114 | algorithms to support. | |
115 | ||
116 | The B<algs> argument should be a colon separated list of signature | |
117 | algorithms in order of decreasing preference of the form B<algorithm+hash> | |
118 | or B<signature_scheme>. B<algorithm> is one of B<RSA>, B<DSA> or B<ECDSA> and | |
119 | B<hash> is a supported algorithm OID short name such as B<SHA1>, B<SHA224>, | |
120 | B<SHA256>, B<SHA384> of B<SHA512>. Note: algorithm and hash names are case | |
121 | sensitive. B<signature_scheme> is one of the signature schemes defined in | |
122 | TLSv1.3, specified using the IETF name, e.g., B<ecdsa_secp256r1_sha256>, | |
123 | B<ed25519>, or B<rsa_pss_pss_sha256>. | |
ec2f7e56 | 124 | |
8b3efb53 RS |
125 | If this option is not set then all signature algorithms supported by the |
126 | OpenSSL library are permissible. | |
c557f921 | 127 | |
8b3efb53 RS |
128 | Note: algorithms which specify a PKCS#1 v1.5 signature scheme (either by |
129 | using B<RSA> as the B<algorithm> or by using one of the B<rsa_pkcs1_*> | |
130 | identifiers) are ignored in TLSv1.3 and will not be negotiated. | |
c557f921 | 131 | |
8b3efb53 | 132 | =item B<-client_sigalgs> I<algs> |
c649d10d | 133 | |
8b3efb53 RS |
134 | This sets the supported signature algorithms associated with client |
135 | authentication for TLSv1.2 and TLSv1.3. For servers the B<algs> is used | |
136 | in the B<signature_algorithms> field of a B<CertificateRequest> message. | |
137 | For clients it is used to determine which signature algorithm to use with | |
138 | the client certificate. If a server does not request a certificate this | |
139 | option has no effect. | |
c649d10d | 140 | |
8b3efb53 RS |
141 | The syntax of B<algs> is identical to B<-sigalgs>. If not set, then the |
142 | value set for B<-sigalgs> will be used instead. | |
db0f35dd | 143 | |
8b3efb53 | 144 | =item B<-groups> I<groups> |
db0f35dd | 145 | |
8b3efb53 RS |
146 | This sets the supported groups. For clients, the groups are sent using |
147 | the supported groups extension. For servers, it is used to determine which | |
148 | group to use. This setting affects groups used for signatures (in TLSv1.2 | |
149 | and earlier) and key exchange. The first group listed will also be used | |
150 | for the B<key_share> sent by a client in a TLSv1.3 B<ClientHello>. | |
7946ab33 | 151 | |
8b3efb53 RS |
152 | The B<groups> argument is a colon separated list of groups. The group can |
153 | be either the B<NIST> name (e.g. B<P-256>), some other commonly used name | |
154 | where applicable (e.g. B<X25519>, B<ffdhe2048>) or an OpenSSL OID name | |
8c1cbc72 | 155 | (e.g. B<prime256v1>). Group names are case sensitive. The list should be |
8b3efb53 | 156 | in order of preference with the most preferred group first. |
7946ab33 | 157 | |
8b3efb53 RS |
158 | Currently supported groups for B<TLSv1.3> are B<P-256>, B<P-384>, B<P-521>, |
159 | B<X25519>, B<X448>, B<ffdhe2048>, B<ffdhe3072>, B<ffdhe4096>, B<ffdhe6144>, | |
160 | B<ffdhe8192>. | |
13cfb043 | 161 | |
8b3efb53 | 162 | =item B<-curves> I<groups> |
13cfb043 | 163 | |
8b3efb53 | 164 | This is a synonym for the B<-groups> command. |
13cfb043 | 165 | |
8b3efb53 | 166 | =item B<-named_curve> I<curve> |
13cfb043 | 167 | |
8b3efb53 RS |
168 | This sets the temporary curve used for ephemeral ECDH modes. Only used |
169 | by servers. | |
13cfb043 | 170 | |
8b3efb53 RS |
171 | The B<groups> argument is a curve name or the special value B<auto> which |
172 | picks an appropriate curve based on client and server preferences. The | |
173 | curve can be either the B<NIST> name (e.g. B<P-256>) or an OpenSSL OID name | |
8c1cbc72 | 174 | (e.g. B<prime256v1>). Curve names are case sensitive. |
cc5a9ba4 | 175 | |
8b3efb53 | 176 | =item B<-cipher> I<ciphers> |
cc5a9ba4 | 177 | |
8b3efb53 RS |
178 | Sets the TLSv1.2 and below ciphersuite list to B<ciphers>. This list will be |
179 | combined with any configured TLSv1.3 ciphersuites. Note: syntax checking | |
180 | of B<ciphers> is currently not performed unless a B<SSL> or B<SSL_CTX> | |
181 | structure is associated with B<ctx>. | |
13cfb043 | 182 | |
8b3efb53 | 183 | =item B<-ciphersuites> I<1.3ciphers> |
13cfb043 | 184 | |
8b3efb53 RS |
185 | Sets the available ciphersuites for TLSv1.3 to value. This is a |
186 | colon-separated list of TLSv1.3 ciphersuite names in order of preference. This | |
187 | list will be combined any configured TLSv1.2 and below ciphersuites. | |
188 | See L<openssl-ciphers(1)> for more information. | |
13cfb043 | 189 | |
8b3efb53 | 190 | =item B<-min_protocol> I<minprot>, B<-max_protocol> I<maxprot> |
13cfb043 | 191 | |
77174598 VD |
192 | Sets the minimum and maximum supported protocol. |
193 | Currently supported protocol values are B<SSLv3>, B<TLSv1>, B<TLSv1.1>, | |
194 | B<TLSv1.2>, B<TLSv1.3> for TLS; B<DTLSv1>, B<DTLSv1.2> for DTLS, and B<None> | |
195 | for no limit. | |
196 | If either the lower or upper bound is not specified then only the other bound | |
197 | applies, if specified. | |
198 | If your application supports both TLS and DTLS you can specify any of these | |
199 | options twice, once with a bound for TLS and again with an appropriate bound | |
200 | for DTLS. | |
201 | To restrict the supported protocol versions use these commands rather than the | |
202 | deprecated alternative commands below. | |
13cfb043 | 203 | |
8b3efb53 | 204 | =item B<-record_padding> I<padding> |
e1c7871d | 205 | |
8b3efb53 RS |
206 | Attempts to pad TLSv1.3 records so that they are a multiple of B<padding> |
207 | in length on send. A B<padding> of 0 or 1 turns off padding. Otherwise, | |
208 | the B<padding> must be >1 or <=16384. | |
e1c7871d | 209 | |
8b3efb53 | 210 | =item B<-debug_broken_protocol> |
f0ef019d | 211 | |
03e16083 RS |
212 | Ignored. |
213 | ||
8b3efb53 | 214 | =item B<-no_middlebox> |
f0ef019d | 215 | |
03e16083 RS |
216 | Turn off "middlebox compatibility", as described below. |
217 | ||
8b3efb53 | 218 | =back |
13cfb043 | 219 | |
8b3efb53 | 220 | =head2 Additional Options |
13cfb043 | 221 | |
8b3efb53 RS |
222 | The following options are accepted by SSL_CONF_cmd(), but are not |
223 | processed by the OpenSSL commands. | |
13cfb043 | 224 | |
8b3efb53 | 225 | =over 4 |
13cfb043 | 226 | |
8b3efb53 | 227 | =item B<-cert> I<file> |
4e2bd9cb | 228 | |
8b3efb53 RS |
229 | Attempts to use B<file> as the certificate for the appropriate context. It |
230 | currently uses SSL_CTX_use_certificate_chain_file() if an B<SSL_CTX> | |
231 | structure is set or SSL_use_certificate_file() with filetype PEM if an | |
232 | B<SSL> structure is set. This option is only supported if certificate | |
233 | operations are permitted. | |
4e2bd9cb | 234 | |
8b3efb53 | 235 | =item B<-key> I<file> |
13cfb043 | 236 | |
8b3efb53 RS |
237 | Attempts to use B<file> as the private key for the appropriate context. This |
238 | option is only supported if certificate operations are permitted. Note: | |
239 | if no B<-key> option is set then a private key is not loaded unless the | |
240 | flag B<SSL_CONF_FLAG_REQUIRE_PRIVATE> is set. | |
241 | ||
242 | =item B<-dhparam> I<file> | |
243 | ||
244 | Attempts to use B<file> as the set of temporary DH parameters for | |
245 | the appropriate context. This option is only supported if certificate | |
246 | operations are permitted. | |
247 | ||
248 | =item B<-no_ssl3>, B<-no_tls1>, B<-no_tls1_1>, B<-no_tls1_2>, B<-no_tls1_3> | |
249 | ||
250 | Disables protocol support for SSLv3, TLSv1.0, TLSv1.1, TLSv1.2 or TLSv1.3 by | |
251 | setting the corresponding options B<SSL_OP_NO_SSLv3>, B<SSL_OP_NO_TLSv1>, | |
252 | B<SSL_OP_NO_TLSv1_1>, B<SSL_OP_NO_TLSv1_2> and B<SSL_OP_NO_TLSv1_3> | |
253 | respectively. These options are deprecated, use B<-min_protocol> and | |
254 | B<-max_protocol> instead. | |
13cfb043 | 255 | |
3bb5e5b0 MC |
256 | =item B<-anti_replay>, B<-no_anti_replay> |
257 | ||
258 | Switches replay protection, on or off respectively. With replay protection on, | |
259 | OpenSSL will automatically detect if a session ticket has been used more than | |
260 | once, TLSv1.3 has been negotiated, and early data is enabled on the server. A | |
261 | full handshake is forced if a session ticket is used a second or subsequent | |
262 | time. Anti-Replay is on by default unless overridden by a configuration file and | |
263 | is only used by servers. Anti-replay measures are required for compliance with | |
264 | the TLSv1.3 specification. Some applications may be able to mitigate the replay | |
265 | risks in other ways and in such cases the built-in OpenSSL functionality is not | |
266 | required. Switching off anti-replay is equivalent to B<SSL_OP_NO_ANTI_REPLAY>. | |
267 | ||
13cfb043 | 268 | =back |
3db935a9 DSH |
269 | |
270 | =head1 SUPPORTED CONFIGURATION FILE COMMANDS | |
271 | ||
8b3efb53 | 272 | Currently supported B<option> names for configuration files (i.e., when the |
3db935a9 | 273 | flag B<SSL_CONF_FLAG_FILE> is set) are listed below. All configuration file |
8b3efb53 | 274 | B<option> names are case insensitive so B<signaturealgorithms> is recognised |
c7b7984a | 275 | as well as B<SignatureAlgorithms>. Unless otherwise stated the B<value> names |
3db935a9 DSH |
276 | are also case insensitive. |
277 | ||
8b3efb53 | 278 | Note: the command prefix (if set) alters the recognised B<option> values. |
3db935a9 DSH |
279 | |
280 | =over 4 | |
281 | ||
65f2a565 | 282 | =item B<CipherString> |
3db935a9 | 283 | |
9d2674cd MC |
284 | Sets the ciphersuite list for TLSv1.2 and below to B<value>. This list will be |
285 | combined with any configured TLSv1.3 ciphersuites. Note: syntax | |
286 | checking of B<value> is currently not performed unless an B<SSL> or B<SSL_CTX> | |
8b3efb53 | 287 | structure is associated with B<ctx>. |
9d2674cd MC |
288 | |
289 | =item B<Ciphersuites> | |
290 | ||
8b3efb53 RS |
291 | Sets the available ciphersuites for TLSv1.3 to B<value>. This is a |
292 | colon-separated list of TLSv1.3 ciphersuite names in order of preference. This | |
9d2674cd | 293 | list will be combined any configured TLSv1.2 and below ciphersuites. |
1903a9b7 | 294 | See L<openssl-ciphers(1)> for more information. |
3db935a9 | 295 | |
ec2f7e56 DSH |
296 | =item B<Certificate> |
297 | ||
298 | Attempts to use the file B<value> as the certificate for the appropriate | |
fc1d88f0 RS |
299 | context. It currently uses SSL_CTX_use_certificate_chain_file() if an B<SSL_CTX> |
300 | structure is set or SSL_use_certificate_file() with filetype PEM if an B<SSL> | |
ec2f7e56 DSH |
301 | structure is set. This option is only supported if certificate operations |
302 | are permitted. | |
303 | ||
304 | =item B<PrivateKey> | |
305 | ||
306 | Attempts to use the file B<value> as the private key for the appropriate | |
307 | context. This option is only supported if certificate operations | |
2011b169 DSH |
308 | are permitted. Note: if no B<PrivateKey> option is set then a private key is |
309 | not loaded unless the B<SSL_CONF_FLAG_REQUIRE_PRIVATE> is set. | |
ec2f7e56 | 310 | |
429261d0 DSH |
311 | =item B<ChainCAFile>, B<ChainCAPath>, B<VerifyCAFile>, B<VerifyCAPath> |
312 | ||
313 | These options indicate a file or directory used for building certificate | |
314 | chains or verifying certificate chains. These options are only supported | |
315 | if certificate operations are permitted. | |
316 | ||
5a185729 DSH |
317 | =item B<RequestCAFile> |
318 | ||
319 | This option indicates a file containing a set of certificates in PEM form. | |
320 | The subject names of the certificates are sent to the peer in the | |
321 | B<certificate_authorities> extension for TLS 1.3 (in ClientHello or | |
322 | CertificateRequest) or in a certificate request for previous versions or | |
323 | TLS. | |
324 | ||
5b7f36e8 DSH |
325 | =item B<ServerInfoFile> |
326 | ||
327 | Attempts to use the file B<value> in the "serverinfo" extension using the | |
328 | function SSL_CTX_use_serverinfo_file. | |
329 | ||
c557f921 DSH |
330 | =item B<DHParameters> |
331 | ||
332 | Attempts to use the file B<value> as the set of temporary DH parameters for | |
333 | the appropriate context. This option is only supported if certificate | |
334 | operations are permitted. | |
335 | ||
c649d10d TS |
336 | =item B<RecordPadding> |
337 | ||
322755cc | 338 | Attempts to pad TLSv1.3 records so that they are a multiple of B<value> in |
c649d10d TS |
339 | length on send. A B<value> of 0 or 1 turns off padding. Otherwise, the |
340 | B<value> must be >1 or <=16384. | |
341 | ||
3db935a9 DSH |
342 | =item B<SignatureAlgorithms> |
343 | ||
322755cc HK |
344 | This sets the supported signature algorithms for TLSv1.2 and TLSv1.3. |
345 | For clients this | |
3db935a9 DSH |
346 | value is used directly for the supported signature algorithms extension. For |
347 | servers it is used to determine which signature algorithms to support. | |
348 | ||
349 | The B<value> argument should be a colon separated list of signature algorithms | |
322755cc HK |
350 | in order of decreasing preference of the form B<algorithm+hash> or |
351 | B<signature_scheme>. B<algorithm> | |
3db935a9 DSH |
352 | is one of B<RSA>, B<DSA> or B<ECDSA> and B<hash> is a supported algorithm |
353 | OID short name such as B<SHA1>, B<SHA224>, B<SHA256>, B<SHA384> of B<SHA512>. | |
354 | Note: algorithm and hash names are case sensitive. | |
322755cc HK |
355 | B<signature_scheme> is one of the signature schemes defined in TLSv1.3, |
356 | specified using the IETF name, e.g., B<ecdsa_secp256r1_sha256>, B<ed25519>, | |
357 | or B<rsa_pss_pss_sha256>. | |
3db935a9 DSH |
358 | |
359 | If this option is not set then all signature algorithms supported by the | |
360 | OpenSSL library are permissible. | |
361 | ||
322755cc HK |
362 | Note: algorithms which specify a PKCS#1 v1.5 signature scheme (either by |
363 | using B<RSA> as the B<algorithm> or by using one of the B<rsa_pkcs1_*> | |
364 | identifiers) are ignored in TLSv1.3 and will not be negotiated. | |
365 | ||
3db935a9 DSH |
366 | =item B<ClientSignatureAlgorithms> |
367 | ||
368 | This sets the supported signature algorithms associated with client | |
322755cc HK |
369 | authentication for TLSv1.2 and TLSv1.3. |
370 | For servers the value is used in the | |
371 | B<signature_algorithms> field of a B<CertificateRequest> message. | |
372 | For clients it is | |
373 | used to determine which signature algorithm to use with the client certificate. | |
374 | If a server does not request a certificate this option has no effect. | |
3db935a9 DSH |
375 | |
376 | The syntax of B<value> is identical to B<SignatureAlgorithms>. If not set then | |
377 | the value set for B<SignatureAlgorithms> will be used instead. | |
378 | ||
47f7cf05 | 379 | =item B<Groups> |
3db935a9 | 380 | |
47f7cf05 MC |
381 | This sets the supported groups. For clients, the groups are |
382 | sent using the supported groups extension. For servers, it is used | |
322755cc HK |
383 | to determine which group to use. This setting affects groups used for |
384 | signatures (in TLSv1.2 and earlier) and key exchange. The first group listed | |
385 | will also be used for the B<key_share> sent by a client in a TLSv1.3 | |
386 | B<ClientHello>. | |
3db935a9 | 387 | |
47f7cf05 MC |
388 | The B<value> argument is a colon separated list of groups. The group can be |
389 | either the B<NIST> name (e.g. B<P-256>), some other commonly used name where | |
dfa1f547 | 390 | applicable (e.g. B<X25519>, B<ffdhe2048>) or an OpenSSL OID name |
8c1cbc72 | 391 | (e.g. B<prime256v1>). Group names are case sensitive. The list should be in |
dfa1f547 | 392 | order of preference with the most preferred group first. |
393 | ||
394 | Currently supported groups for B<TLSv1.3> are B<P-256>, B<P-384>, B<P-521>, | |
395 | B<X25519>, B<X448>, B<ffdhe2048>, B<ffdhe3072>, B<ffdhe4096>, B<ffdhe6144>, | |
396 | B<ffdhe8192>. | |
47f7cf05 MC |
397 | |
398 | =item B<Curves> | |
399 | ||
400 | This is a synonym for the "Groups" command. | |
3db935a9 | 401 | |
7946ab33 KR |
402 | =item B<MinProtocol> |
403 | ||
404 | This sets the minimum supported SSL, TLS or DTLS version. | |
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>. |
77174598 VD |
408 | The SSL and TLS bounds apply only to TLS-based contexts, while the DTLS bounds |
409 | apply only to DTLS-based contexts. | |
410 | The command can be repeated with one instance setting a TLS bound, and the | |
411 | other setting a DTLS bound. | |
412 | The value B<None> applies to both types of contexts and disables the limits. | |
7946ab33 KR |
413 | |
414 | =item B<MaxProtocol> | |
415 | ||
416 | This sets the maximum supported SSL, TLS or DTLS version. | |
417 | ||
57ce7b61 | 418 | Currently supported protocol values are B<SSLv3>, B<TLSv1>, B<TLSv1.1>, |
322755cc | 419 | B<TLSv1.2>, B<TLSv1.3>, B<DTLSv1> and B<DTLSv1.2>. |
77174598 VD |
420 | The SSL and TLS bounds apply only to TLS-based contexts, while the DTLS bounds |
421 | apply only to DTLS-based contexts. | |
422 | The command can be repeated with one instance setting a TLS bound, and the | |
423 | other setting a DTLS bound. | |
424 | The value B<None> applies to both types of contexts and disables the limits. | |
7946ab33 | 425 | |
3db935a9 DSH |
426 | =item B<Protocol> |
427 | ||
57ce7b61 VD |
428 | This can be used to enable or disable certain versions of the SSL, |
429 | TLS or DTLS protocol. | |
7946ab33 | 430 | |
57ce7b61 VD |
431 | The B<value> argument is a comma separated list of supported protocols |
432 | to enable or disable. | |
7946ab33 KR |
433 | If a protocol is preceded by B<-> that version is disabled. |
434 | ||
435 | All protocol versions are enabled by default. | |
57ce7b61 VD |
436 | You need to disable at least one protocol version for this setting have any |
437 | effect. | |
438 | Only enabling some protocol versions does not disable the other protocol | |
439 | versions. | |
7946ab33 | 440 | |
57ce7b61 | 441 | Currently supported protocol values are B<SSLv3>, B<TLSv1>, B<TLSv1.1>, |
322755cc | 442 | B<TLSv1.2>, B<TLSv1.3>, B<DTLSv1> and B<DTLSv1.2>. |
7946ab33 | 443 | The special value B<ALL> refers to all supported versions. |
3db935a9 | 444 | |
57ce7b61 VD |
445 | This can't enable protocols that are disabled using B<MinProtocol> |
446 | or B<MaxProtocol>, but can disable protocols that are still allowed | |
447 | by them. | |
7946ab33 KR |
448 | |
449 | The B<Protocol> command is fragile and deprecated; do not use it. | |
450 | Use B<MinProtocol> and B<MaxProtocol> instead. | |
57ce7b61 VD |
451 | If you do use B<Protocol>, make sure that the resulting range of enabled |
452 | protocols has no "holes", e.g. if TLS 1.0 and TLS 1.2 are both enabled, make | |
453 | sure to also leave TLS 1.1 enabled. | |
3db935a9 DSH |
454 | |
455 | =item B<Options> | |
456 | ||
457 | The B<value> argument is a comma separated list of various flags to set. | |
8106cb8b VD |
458 | If a flag string is preceded B<-> it is disabled. |
459 | See the L<SSL_CTX_set_options(3)> function for more details of | |
460 | individual options. | |
3db935a9 DSH |
461 | |
462 | Each option is listed below. Where an operation is enabled by default | |
463 | the B<-flag> syntax is needed to disable it. | |
464 | ||
465 | B<SessionTicket>: session ticket support, enabled by default. Inverse of | |
466 | B<SSL_OP_NO_TICKET>: that is B<-SessionTicket> is the same as setting | |
467 | B<SSL_OP_NO_TICKET>. | |
468 | ||
469 | B<Compression>: SSL/TLS compression support, enabled by default. Inverse | |
470 | of B<SSL_OP_NO_COMPRESSION>. | |
471 | ||
472 | B<EmptyFragments>: use empty fragments as a countermeasure against a | |
473 | SSL 3.0/TLS 1.0 protocol vulnerability affecting CBC ciphers. It | |
474 | is set by default. Inverse of B<SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS>. | |
475 | ||
c7b7984a | 476 | B<Bugs>: enable various bug workarounds. Same as B<SSL_OP_ALL>. |
3db935a9 | 477 | |
c7b7984a | 478 | B<DHSingle>: enable single use DH keys, set by default. Inverse of |
3db935a9 DSH |
479 | B<SSL_OP_DH_SINGLE>. Only used by servers. |
480 | ||
e1c7871d | 481 | B<ECDHSingle>: enable single use ECDH keys, set by default. Inverse of |
3db935a9 DSH |
482 | B<SSL_OP_ECDH_SINGLE>. Only used by servers. |
483 | ||
e1c7871d | 484 | B<ServerPreference>: use server and not client preference order when |
3db935a9 DSH |
485 | determining which cipher suite, signature algorithm or elliptic curve |
486 | to use for an incoming connection. Equivalent to | |
487 | B<SSL_OP_CIPHER_SERVER_PREFERENCE>. Only used by servers. | |
488 | ||
e1c7871d TS |
489 | B<PrioritizeChaCha>: prioritizes ChaCha ciphers when the client has a |
490 | ChaCha20 cipher at the top of its preference list. This usually indicates | |
491 | a mobile client is in use. Equivalent to B<SSL_OP_PRIORITIZE_CHACHA>. | |
492 | Only used by servers. | |
493 | ||
494 | B<NoResumptionOnRenegotiation>: set | |
f0ef019d DSH |
495 | B<SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION> flag. Only used by servers. |
496 | ||
4ac5e43d HK |
497 | B<NoRenegotiation>: disables all attempts at renegotiation in TLSv1.2 and |
498 | earlier, same as setting B<SSL_OP_NO_RENEGOTIATION>. | |
499 | ||
e1c7871d | 500 | B<UnsafeLegacyRenegotiation>: permits the use of unsafe legacy renegotiation. |
3db935a9 DSH |
501 | Equivalent to B<SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION>. |
502 | ||
e1c7871d | 503 | B<UnsafeLegacyServerConnect>: permits the use of unsafe legacy renegotiation |
3db935a9 DSH |
504 | for OpenSSL clients only. Equivalent to B<SSL_OP_LEGACY_SERVER_CONNECT>. |
505 | Set by default. | |
506 | ||
b3618f44 EK |
507 | B<EncryptThenMac>: use encrypt-then-mac extension, enabled by |
508 | default. Inverse of B<SSL_OP_NO_ENCRYPT_THEN_MAC>: that is, | |
509 | B<-EncryptThenMac> is the same as setting B<SSL_OP_NO_ENCRYPT_THEN_MAC>. | |
4e2bd9cb MC |
510 | |
511 | B<AllowNoDHEKEX>: In TLSv1.3 allow a non-(ec)dhe based key exchange mode on | |
512 | resumption. This means that there will be no forward secrecy for the resumed | |
513 | session. Equivalent to B<SSL_OP_ALLOW_NO_DHE_KEX>. | |
b3618f44 | 514 | |
1c4b1545 MC |
515 | B<MiddleboxCompat>: If set then dummy Change Cipher Spec (CCS) messages are sent |
516 | in TLSv1.3. This has the effect of making TLSv1.3 look more like TLSv1.2 so that | |
517 | middleboxes that do not understand TLSv1.3 will not drop the connection. This | |
518 | option is set by default. A future version of OpenSSL may not set this by | |
519 | default. Equivalent to B<SSL_OP_ENABLE_MIDDLEBOX_COMPAT>. | |
520 | ||
3bb5e5b0 MC |
521 | B<AntiReplay>: If set then OpenSSL will automatically detect if a session ticket |
522 | has been used more than once, TLSv1.3 has been negotiated, and early data is | |
523 | enabled on the server. A full handshake is forced if a session ticket is used a | |
524 | second or subsequent time. This option is set by default and is only used by | |
525 | servers. Anti-replay measures are required to comply with the TLSv1.3 | |
526 | specification. Some applications may be able to mitigate the replay risks in | |
527 | other ways and in such cases the built-in OpenSSL functionality is not required. | |
528 | Disabling anti-replay is equivalent to setting B<SSL_OP_NO_ANTI_REPLAY>. | |
529 | ||
088dfa13 TS |
530 | B<ExtendedMasterSecret>: use extended master secret extension, enabled by |
531 | default. Inverse of B<SSL_OP_NO_EXTENDED_MASTER_SECRET>: that is, | |
532 | B<-ExtendedMasterSecret> is the same as setting B<SSL_OP_NO_EXTENDED_MASTER_SECRET>. | |
533 | ||
90fc2c26 NM |
534 | B<CANames>: use CA names extension, enabled by |
535 | default. Inverse of B<SSL_OP_DISABLE_TLSEXT_CA_NAMES>: that is, | |
536 | B<-CANames> is the same as setting B<SSL_OP_DISABLE_TLSEXT_CA_NAMES>. | |
537 | ||
6878f430 MC |
538 | B<KTLS>: Enables kernel TLS if support has been compiled in, and it is supported |
539 | by the negotiated ciphersuites and extensions. Equivalent to | |
540 | B<SSL_OP_ENABLE_KTLS>. | |
541 | ||
429261d0 DSH |
542 | =item B<VerifyMode> |
543 | ||
544 | The B<value> argument is a comma separated list of flags to set. | |
545 | ||
546 | B<Peer> enables peer verification: for clients only. | |
547 | ||
548 | B<Request> requests but does not require a certificate from the client. | |
549 | Servers only. | |
550 | ||
551 | B<Require> requests and requires a certificate from the client: an error | |
552 | occurs if the client does not present a certificate. Servers only. | |
553 | ||
554 | B<Once> requests a certificate from a client only on the initial connection: | |
555 | not when renegotiating. Servers only. | |
556 | ||
9d75dce3 TS |
557 | B<RequestPostHandshake> configures the connection to support requests but does |
558 | not require a certificate from the client post-handshake. A certificate will | |
559 | not be requested during the initial handshake. The server application must | |
560 | provide a mechanism to request a certificate post-handshake. Servers only. | |
561 | TLSv1.3 only. | |
562 | ||
563 | B<RequiresPostHandshake> configures the connection to support requests and | |
564 | requires a certificate from the client post-handshake: an error occurs if the | |
565 | client does not present a certificate. A certificate will not be requested | |
566 | during the initial handshake. The server application must provide a mechanism | |
567 | to request a certificate post-handshake. Servers only. TLSv1.3 only. | |
568 | ||
429261d0 DSH |
569 | =item B<ClientCAFile>, B<ClientCAPath> |
570 | ||
571 | A file or directory of certificates in PEM format whose names are used as the | |
572 | set of acceptable names for client CAs. Servers only. This option is only | |
573 | supported if certificate operations are permitted. | |
574 | ||
3db935a9 DSH |
575 | =back |
576 | ||
ec2f7e56 DSH |
577 | =head1 SUPPORTED COMMAND TYPES |
578 | ||
579 | The function SSL_CONF_cmd_value_type() currently returns one of the following | |
580 | types: | |
581 | ||
582 | =over 4 | |
583 | ||
584 | =item B<SSL_CONF_TYPE_UNKNOWN> | |
585 | ||
8b3efb53 | 586 | The B<option> string is unrecognised, this return value can be use to flag |
ec2f7e56 DSH |
587 | syntax errors. |
588 | ||
589 | =item B<SSL_CONF_TYPE_STRING> | |
590 | ||
591 | The value is a string without any specific structure. | |
592 | ||
593 | =item B<SSL_CONF_TYPE_FILE> | |
594 | ||
9c0586d5 | 595 | The value is a filename. |
ec2f7e56 DSH |
596 | |
597 | =item B<SSL_CONF_TYPE_DIR> | |
598 | ||
599 | The value is a directory name. | |
600 | ||
656b2605 DSH |
601 | =item B<SSL_CONF_TYPE_NONE> |
602 | ||
603 | The value string is not used e.g. a command line option which doesn't take an | |
604 | argument. | |
605 | ||
fa9d77dc CR |
606 | =back |
607 | ||
3db935a9 DSH |
608 | =head1 NOTES |
609 | ||
610 | The order of operations is significant. This can be used to set either defaults | |
611 | or values which cannot be overridden. For example if an application calls: | |
612 | ||
87d9cafa | 613 | SSL_CONF_cmd(ctx, "Protocol", "-SSLv3"); |
3db935a9 DSH |
614 | SSL_CONF_cmd(ctx, userparam, uservalue); |
615 | ||
87d9cafa | 616 | it will disable SSLv3 support by default but the user can override it. If |
3db935a9 DSH |
617 | however the call sequence is: |
618 | ||
619 | SSL_CONF_cmd(ctx, userparam, uservalue); | |
87d9cafa | 620 | SSL_CONF_cmd(ctx, "Protocol", "-SSLv3"); |
3db935a9 | 621 | |
87d9cafa | 622 | SSLv3 is B<always> disabled and attempt to override this by the user are |
3db935a9 DSH |
623 | ignored. |
624 | ||
f5f85f75 | 625 | By checking the return code of SSL_CONF_cmd() it is possible to query if a |
8b3efb53 | 626 | given B<option> is recognised, this is useful if SSL_CONF_cmd() values are |
3db935a9 DSH |
627 | mixed with additional application specific operations. |
628 | ||
f5f85f75 | 629 | For example an application might call SSL_CONF_cmd() and if it returns |
3db935a9 DSH |
630 | -2 (unrecognised command) continue with processing of application specific |
631 | commands. | |
632 | ||
f5f85f75 JS |
633 | Applications can also use SSL_CONF_cmd() to process command lines though the |
634 | utility function SSL_CONF_cmd_argv() is normally used instead. One way | |
821244cf | 635 | to do this is to set the prefix to an appropriate value using |
8b3efb53 | 636 | SSL_CONF_CTX_set1_prefix(), pass the current argument to B<option> and the |
821244cf | 637 | following argument to B<value> (which may be NULL). |
3db935a9 DSH |
638 | |
639 | In this case if the return value is positive then it is used to skip that | |
f5f85f75 | 640 | number of arguments as they have been processed by SSL_CONF_cmd(). If -2 is |
8b3efb53 | 641 | returned then B<option> is not recognised and application specific arguments |
3db935a9 DSH |
642 | can be checked instead. If -3 is returned a required argument is missing |
643 | and an error is indicated. If 0 is returned some other error occurred and | |
644 | this can be reported back to the user. | |
645 | ||
7946ab33 | 646 | The function SSL_CONF_cmd_value_type() can be used by applications to |
ec2f7e56 DSH |
647 | check for the existence of a command or to perform additional syntax |
648 | checking or translation of the command value. For example if the return | |
649 | value is B<SSL_CONF_TYPE_FILE> an application could translate a relative | |
650 | pathname to an absolute pathname. | |
651 | ||
4564e77a PY |
652 | =head1 RETURN VALUES |
653 | ||
8b3efb53 RS |
654 | SSL_CONF_cmd() returns 1 if the value of B<option> is recognised and B<value> is |
655 | B<NOT> used and 2 if both B<option> and B<value> are used. In other words it | |
4564e77a PY |
656 | returns the number of arguments processed. This is useful when processing |
657 | command lines. | |
658 | ||
8b3efb53 | 659 | A return value of -2 means B<option> is not recognised. |
4564e77a | 660 | |
8b3efb53 | 661 | A return value of -3 means B<option> is recognised and the command requires a |
4564e77a PY |
662 | value but B<value> is NULL. |
663 | ||
8b3efb53 | 664 | A return code of 0 indicates that both B<option> and B<value> are valid but an |
4564e77a PY |
665 | error occurred attempting to perform the operation: for example due to an |
666 | error in the syntax of B<value> in this case the error queue may provide | |
667 | additional information. | |
668 | ||
3db935a9 DSH |
669 | =head1 EXAMPLES |
670 | ||
671 | Set supported signature algorithms: | |
672 | ||
673 | SSL_CONF_cmd(ctx, "SignatureAlgorithms", "ECDSA+SHA256:RSA+SHA256:DSA+SHA256"); | |
674 | ||
24c2cd39 | 675 | There are various ways to select the supported protocols. |
7946ab33 KR |
676 | |
677 | This set the minimum protocol version to TLSv1, and so disables SSLv3. | |
678 | This is the recommended way to disable protocols. | |
679 | ||
680 | SSL_CONF_cmd(ctx, "MinProtocol", "TLSv1"); | |
681 | ||
682 | The following also disables SSLv3: | |
683 | ||
684 | SSL_CONF_cmd(ctx, "Protocol", "-SSLv3"); | |
685 | ||
57ce7b61 VD |
686 | The following will first enable all protocols, and then disable |
687 | SSLv3. | |
688 | If no protocol versions were disabled before this has the same effect as | |
689 | "-SSLv3", but if some versions were disables this will re-enable them before | |
690 | disabling SSLv3. | |
3db935a9 | 691 | |
87d9cafa | 692 | SSL_CONF_cmd(ctx, "Protocol", "ALL,-SSLv3"); |
3db935a9 DSH |
693 | |
694 | Only enable TLSv1.2: | |
695 | ||
7946ab33 KR |
696 | SSL_CONF_cmd(ctx, "MinProtocol", "TLSv1.2"); |
697 | SSL_CONF_cmd(ctx, "MaxProtocol", "TLSv1.2"); | |
698 | ||
699 | This also only enables TLSv1.2: | |
700 | ||
3db935a9 DSH |
701 | SSL_CONF_cmd(ctx, "Protocol", "-ALL,TLSv1.2"); |
702 | ||
703 | Disable TLS session tickets: | |
704 | ||
705 | SSL_CONF_cmd(ctx, "Options", "-SessionTicket"); | |
706 | ||
dc5744cb EK |
707 | Enable compression: |
708 | ||
709 | SSL_CONF_cmd(ctx, "Options", "Compression"); | |
710 | ||
3db935a9 DSH |
711 | Set supported curves to P-256, P-384: |
712 | ||
713 | SSL_CONF_cmd(ctx, "Curves", "P-256:P-384"); | |
714 | ||
3db935a9 DSH |
715 | =head1 SEE ALSO |
716 | ||
98ca37e4 | 717 | L<ssl(7)>, |
9b86974e RS |
718 | L<SSL_CONF_CTX_new(3)>, |
719 | L<SSL_CONF_CTX_set_flags(3)>, | |
720 | L<SSL_CONF_CTX_set1_prefix(3)>, | |
721 | L<SSL_CONF_CTX_set_ssl_ctx(3)>, | |
8106cb8b VD |
722 | L<SSL_CONF_cmd_argv(3)>, |
723 | L<SSL_CTX_set_options(3)> | |
3db935a9 DSH |
724 | |
725 | =head1 HISTORY | |
726 | ||
fc5ecadd | 727 | The SSL_CONF_cmd() function was added in OpenSSL 1.0.2. |
3db935a9 | 728 | |
fc5ecadd DMSP |
729 | The B<SSL_OP_NO_SSL2> option doesn't have effect since 1.1.0, but the macro |
730 | is retained for backwards compatibility. | |
45f55f6a | 731 | |
fc5ecadd | 732 | The B<SSL_CONF_TYPE_NONE> was added in OpenSSL 1.1.0. In earlier versions of |
656b2605 DSH |
733 | OpenSSL passing a command which didn't take an argument would return |
734 | B<SSL_CONF_TYPE_UNKNOWN>. | |
735 | ||
7946ab33 KR |
736 | B<MinProtocol> and B<MaxProtocol> where added in OpenSSL 1.1.0. |
737 | ||
e1c7871d TS |
738 | B<AllowNoDHEKEX> and B<PrioritizeChaCha> were added in OpenSSL 1.1.1. |
739 | ||
e2f92610 RS |
740 | =head1 COPYRIGHT |
741 | ||
f5afac4b | 742 | Copyright 2012-2021 The OpenSSL Project Authors. All Rights Reserved. |
e2f92610 | 743 | |
4746f25a | 744 | Licensed under the Apache License 2.0 (the "License"). You may not use |
e2f92610 RS |
745 | this file except in compliance with the License. You can obtain a copy |
746 | in the file LICENSE in the source distribution or at | |
747 | L<https://www.openssl.org/source/license.html>. | |
748 | ||
749 | =cut |