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