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1 | =pod |
2 | ||
3 | =head1 NAME | |
4 | ||
19d2bb57 | 5 | config - OpenSSL CONF library configuration files |
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6 | |
7 | =head1 DESCRIPTION | |
8 | ||
19d2bb57 | 9 | The OpenSSL CONF library can be used to read configuration files. |
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10 | It is used for the OpenSSL master configuration file B<openssl.cnf> |
11 | and in a few other places like B<SPKAC> files and certificate extension | |
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12 | files for the B<x509> utility. OpenSSL applications can also use the |
13 | CONF library for their own purposes. | |
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14 | |
15 | A configuration file is divided into a number of sections. Each section | |
16 | starts with a line B<[ section_name ]> and ends when a new section is | |
17 | started or end of file is reached. A section name can consist of | |
18 | alphanumeric characters and underscores. | |
19 | ||
20 | The first section of a configuration file is special and is referred | |
21 | to as the B<default> section this is usually unnamed and is from the | |
22 | start of file until the first named section. When a name is being looked up | |
23 | it is first looked up in a named section (if any) and then the | |
24 | default section. | |
25 | ||
26 | The environment is mapped onto a section called B<ENV>. | |
27 | ||
28 | Comments can be included by preceding them with the B<#> character | |
29 | ||
b524b808 TM |
30 | Other files can be included using the B<.include> directive followed |
31 | by a path. If the path points to a directory all files with | |
32 | names ending with B<.cnf> or B<.conf> are included from the directory. | |
33 | Recursive inclusion of directories from files in such directory is not | |
34 | supported. That means the files in the included directory can also contain | |
35 | B<.include> directives but only inclusion of regular files is supported | |
36 | there. The inclusion of directories is not supported on systems without | |
37 | POSIX IO support. | |
38 | ||
39 | It is strongly recommended to use absolute paths with the B<.include> | |
40 | directive. Relative paths are evaluated based on the application current | |
41 | working directory so unless the configuration file containing the | |
42 | B<.include> directive is application specific the inclusion will not | |
43 | work as expected. | |
44 | ||
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45 | Each section in a configuration file consists of a number of name and |
46 | value pairs of the form B<name=value> | |
47 | ||
48 | The B<name> string can contain any alphanumeric characters as well as | |
49 | a few punctuation symbols such as B<.> B<,> B<;> and B<_>. | |
50 | ||
51 | The B<value> string consists of the string following the B<=> character | |
52 | until end of line with any leading and trailing white space removed. | |
53 | ||
54 | The value string undergoes variable expansion. This can be done by | |
55 | including the form B<$var> or B<${var}>: this will substitute the value | |
56 | of the named variable in the current section. It is also possible to | |
57 | substitute a value from another section using the syntax B<$section::name> | |
19d2bb57 | 58 | or B<${section::name}>. By using the form B<$ENV::name> environment |
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59 | variables can be substituted. It is also possible to assign values to |
60 | environment variables by using the name B<ENV::name>, this will work | |
61 | if the program looks up environment variables using the B<CONF> library | |
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62 | instead of calling getenv() directly. The value string must not exceed 64k in |
63 | length after variable expansion. Otherwise an error will occur. | |
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64 | |
65 | It is possible to escape certain characters by using any kind of quote | |
66 | or the B<\> character. By making the last character of a line a B<\> | |
67 | a B<value> string can be spread across multiple lines. In addition | |
657e60fa | 68 | the sequences B<\n>, B<\r>, B<\b> and B<\t> are recognized. |
aba3e65f | 69 | |
b524b808 TM |
70 | All expansion and escape rules as described above that apply to B<value> |
71 | also apply to the path of the B<.include> directive. | |
72 | ||
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73 | =head1 OPENSSL LIBRARY CONFIGURATION |
74 | ||
a528d4f0 | 75 | Applications can automatically configure certain |
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76 | aspects of OpenSSL using the master OpenSSL configuration file, or optionally |
77 | an alternative configuration file. The B<openssl> utility includes this | |
78 | functionality: any sub command uses the master OpenSSL configuration file | |
79 | unless an option is used in the sub command to use an alternative configuration | |
80 | file. | |
81 | ||
1bc74519 | 82 | To enable library configuration the default section needs to contain an |
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83 | appropriate line which points to the main configuration section. The default |
84 | name is B<openssl_conf> which is used by the B<openssl> utility. Other | |
a8c5ed81 | 85 | applications may use an alternative name such as B<myapplication_conf>. |
86 | All library configuration lines appear in the default section at the start | |
87 | of the configuration file. | |
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88 | |
89 | The configuration section should consist of a set of name value pairs which | |
90 | contain specific module configuration information. The B<name> represents | |
1bc74519 | 91 | the name of the I<configuration module> the meaning of the B<value> is |
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92 | module specific: it may, for example, represent a further configuration |
93 | section containing configuration module specific information. E.g. | |
94 | ||
a8c5ed81 | 95 | # This must be in the default section |
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96 | openssl_conf = openssl_init |
97 | ||
98 | [openssl_init] | |
99 | ||
100 | oid_section = new_oids | |
101 | engines = engine_section | |
102 | ||
103 | [new_oids] | |
104 | ||
105 | ... new oids here ... | |
106 | ||
107 | [engine_section] | |
108 | ||
109 | ... engine stuff here ... | |
110 | ||
3d764db7 | 111 | The features of each configuration module are described below. |
a30af36c | 112 | |
05ea606a | 113 | =head2 ASN1 Object Configuration Module |
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114 | |
115 | This module has the name B<oid_section>. The value of this variable points | |
116 | to a section containing name value pairs of OIDs: the name is the OID short | |
117 | and long name, the value is the numerical form of the OID. Although some of | |
118 | the B<openssl> utility sub commands already have their own ASN1 OBJECT section | |
119 | functionality not all do. By using the ASN1 OBJECT configuration module | |
120 | B<all> the B<openssl> utility sub commands can see the new objects as well | |
121 | as any compliant applications. For example: | |
122 | ||
123 | [new_oids] | |
1bc74519 | 124 | |
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125 | some_new_oid = 1.2.3.4 |
126 | some_other_oid = 1.2.3.5 | |
127 | ||
a528d4f0 | 128 | It is also possible to set the value to the long name followed |
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129 | by a comma and the numerical OID form. For example: |
130 | ||
131 | shortName = some object long name, 1.2.3.4 | |
132 | ||
05ea606a | 133 | =head2 Engine Configuration Module |
a30af36c | 134 | |
f2c18125 DSH |
135 | This ENGINE configuration module has the name B<engines>. The value of this |
136 | variable points to a section containing further ENGINE configuration | |
137 | information. | |
138 | ||
139 | The section pointed to by B<engines> is a table of engine names (though see | |
2b4ffc65 | 140 | B<engine_id> below) and further sections containing configuration information |
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141 | specific to each ENGINE. |
142 | ||
143 | Each ENGINE specific section is used to set default algorithms, load | |
144 | dynamic, perform initialization and send ctrls. The actual operation performed | |
145 | depends on the I<command> name which is the name of the name value pair. The | |
146 | currently supported commands are listed below. | |
147 | ||
148 | For example: | |
149 | ||
150 | [engine_section] | |
151 | ||
152 | # Configure ENGINE named "foo" | |
153 | foo = foo_section | |
154 | # Configure ENGINE named "bar" | |
155 | bar = bar_section | |
156 | ||
157 | [foo_section] | |
158 | ... foo ENGINE specific commands ... | |
159 | ||
160 | [bar_section] | |
161 | ... "bar" ENGINE specific commands ... | |
162 | ||
1bc74519 | 163 | The command B<engine_id> is used to give the ENGINE name. If used this |
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164 | command must be first. For example: |
165 | ||
166 | [engine_section] | |
167 | # This would normally handle an ENGINE named "foo" | |
168 | foo = foo_section | |
169 | ||
170 | [foo_section] | |
171 | # Override default name and use "myfoo" instead. | |
172 | engine_id = myfoo | |
173 | ||
174 | The command B<dynamic_path> loads and adds an ENGINE from the given path. It | |
175 | is equivalent to sending the ctrls B<SO_PATH> with the path argument followed | |
176 | by B<LIST_ADD> with value 2 and B<LOAD> to the dynamic ENGINE. If this is | |
177 | not the required behaviour then alternative ctrls can be sent directly | |
178 | to the dynamic ENGINE using ctrl commands. | |
179 | ||
180 | The command B<init> determines whether to initialize the ENGINE. If the value | |
181 | is B<0> the ENGINE will not be initialized, if B<1> and attempt it made to | |
182 | initialized the ENGINE immediately. If the B<init> command is not present | |
183 | then an attempt will be made to initialize the ENGINE after all commands in | |
184 | its section have been processed. | |
185 | ||
186 | The command B<default_algorithms> sets the default algorithms an ENGINE will | |
35cb565a | 187 | supply using the functions ENGINE_set_default_string(). |
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188 | |
189 | If the name matches none of the above command names it is assumed to be a | |
1bc74519 | 190 | ctrl command which is sent to the ENGINE. The value of the command is the |
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191 | argument to the ctrl command. If the value is the string B<EMPTY> then no |
192 | value is sent to the command. | |
193 | ||
194 | For example: | |
195 | ||
196 | ||
197 | [engine_section] | |
198 | ||
199 | # Configure ENGINE named "foo" | |
200 | foo = foo_section | |
201 | ||
202 | [foo_section] | |
203 | # Load engine from DSO | |
204 | dynamic_path = /some/path/fooengine.so | |
205 | # A foo specific ctrl. | |
206 | some_ctrl = some_value | |
207 | # Another ctrl that doesn't take a value. | |
208 | other_ctrl = EMPTY | |
209 | # Supply all default algorithms | |
210 | default_algorithms = ALL | |
a30af36c | 211 | |
05ea606a | 212 | =head2 EVP Configuration Module |
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213 | |
214 | This modules has the name B<alg_section> which points to a section containing | |
215 | algorithm commands. | |
216 | ||
217 | Currently the only algorithm command supported is B<fips_mode> whose | |
b53338cb EK |
218 | value can only be the boolean string B<off>. If B<fips_mode> is set to B<on>, |
219 | an error occurs as this library version is not FIPS capable. | |
3d764db7 | 220 | |
05ea606a | 221 | =head2 SSL Configuration Module |
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222 | |
223 | This module has the name B<ssl_conf> which points to a section containing | |
224 | SSL configurations. | |
225 | ||
226 | Each line in the SSL configuration section contains the name of the | |
227 | configuration and the section containing it. | |
228 | ||
229 | Each configuration section consists of command value pairs for B<SSL_CONF>. | |
230 | Each pair will be passed to a B<SSL_CTX> or B<SSL> structure if it calls | |
231 | SSL_CTX_config() or SSL_config() with the appropriate configuration name. | |
232 | ||
233 | Note: any characters before an initial dot in the configuration section are | |
234 | ignored so the same command can be used multiple times. | |
235 | ||
236 | For example: | |
237 | ||
238 | ssl_conf = ssl_sect | |
239 | ||
240 | [ssl_sect] | |
241 | ||
242 | server = server_section | |
243 | ||
244 | [server_section] | |
245 | ||
246 | RSA.Certificate = server-rsa.pem | |
247 | ECDSA.Certificate = server-ecdsa.pem | |
248 | Ciphers = ALL:!RC4 | |
3d764db7 | 249 | |
8a5ed9dc TM |
250 | The system default configuration with name B<system_default> if present will |
251 | be applied during any creation of the B<SSL_CTX> structure. | |
252 | ||
253 | Example of a configuration with the system default: | |
254 | ||
255 | ssl_conf = ssl_sect | |
256 | ||
257 | [ssl_sect] | |
258 | ||
259 | system_default = system_default_sect | |
260 | ||
261 | [system_default_sect] | |
262 | ||
263 | MinProtocol = TLSv1.2 | |
264 | ||
265 | ||
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266 | =head1 NOTES |
267 | ||
19d2bb57 | 268 | If a configuration file attempts to expand a variable that doesn't exist |
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269 | then an error is flagged and the file will not load. This can happen |
270 | if an attempt is made to expand an environment variable that doesn't | |
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271 | exist. For example in a previous version of OpenSSL the default OpenSSL |
272 | master configuration file used the value of B<HOME> which may not be | |
273 | defined on non Unix systems and would cause an error. | |
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274 | |
275 | This can be worked around by including a B<default> section to provide | |
276 | a default value: then if the environment lookup fails the default value | |
277 | will be used instead. For this to work properly the default value must | |
278 | be defined earlier in the configuration file than the expansion. See | |
279 | the B<EXAMPLES> section for an example of how to do this. | |
280 | ||
281 | If the same variable exists in the same section then all but the last | |
282 | value will be silently ignored. In certain circumstances such as with | |
283 | DNs the same field may occur multiple times. This is usually worked | |
284 | around by ignoring any characters before an initial B<.> e.g. | |
285 | ||
286 | 1.OU="My first OU" | |
287 | 2.OU="My Second OU" | |
288 | ||
289 | =head1 EXAMPLES | |
290 | ||
291 | Here is a sample configuration file using some of the features | |
292 | mentioned above. | |
293 | ||
294 | # This is the default section. | |
1bc74519 | 295 | |
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296 | HOME=/temp |
297 | RANDFILE= ${ENV::HOME}/.rnd | |
298 | configdir=$ENV::HOME/config | |
299 | ||
300 | [ section_one ] | |
301 | ||
302 | # We are now in section one. | |
303 | ||
304 | # Quotes permit leading and trailing whitespace | |
305 | any = " any variable name " | |
306 | ||
307 | other = A string that can \ | |
308 | cover several lines \ | |
309 | by including \\ characters | |
310 | ||
311 | message = Hello World\n | |
312 | ||
313 | [ section_two ] | |
314 | ||
315 | greeting = $section_one::message | |
316 | ||
317 | This next example shows how to expand environment variables safely. | |
318 | ||
319 | Suppose you want a variable called B<tmpfile> to refer to a | |
320 | temporary filename. The directory it is placed in can determined by | |
35ed393e | 321 | the B<TEMP> or B<TMP> environment variables but they may not be |
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322 | set to any value at all. If you just include the environment variable |
323 | names and the variable doesn't exist then this will cause an error when | |
324 | an attempt is made to load the configuration file. By making use of the | |
1bc74519 | 325 | default section both values can be looked up with B<TEMP> taking |
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326 | priority and B</tmp> used if neither is defined: |
327 | ||
328 | TMP=/tmp | |
329 | # The above value is used if TMP isn't in the environment | |
330 | TEMP=$ENV::TMP | |
331 | # The above value is used if TEMP isn't in the environment | |
332 | tmpfile=${ENV::TEMP}/tmp.filename | |
333 | ||
7b68c30d DSH |
334 | Simple OpenSSL library configuration example to enter FIPS mode: |
335 | ||
336 | # Default appname: should match "appname" parameter (if any) | |
337 | # supplied to CONF_modules_load_file et al. | |
338 | openssl_conf = openssl_conf_section | |
339 | ||
340 | [openssl_conf_section] | |
341 | # Configuration module list | |
342 | alg_section = evp_sect | |
343 | ||
344 | [evp_sect] | |
345 | # Set to "yes" to enter FIPS mode if supported | |
346 | fips_mode = yes | |
347 | ||
348 | Note: in the above example you will get an error in non FIPS capable versions | |
349 | of OpenSSL. | |
350 | ||
351 | More complex OpenSSL library configuration. Add OID and don't enter FIPS mode: | |
352 | ||
353 | # Default appname: should match "appname" parameter (if any) | |
354 | # supplied to CONF_modules_load_file et al. | |
355 | openssl_conf = openssl_conf_section | |
356 | ||
357 | [openssl_conf_section] | |
358 | # Configuration module list | |
359 | alg_section = evp_sect | |
360 | oid_section = new_oids | |
361 | ||
362 | [evp_sect] | |
363 | # This will have no effect as FIPS mode is off by default. | |
364 | # Set to "yes" to enter FIPS mode, if supported | |
365 | fips_mode = no | |
366 | ||
367 | [new_oids] | |
368 | # New OID, just short name | |
369 | newoid1 = 1.2.3.4.1 | |
370 | # New OID shortname and long name | |
371 | newoid2 = New OID 2 long name, 1.2.3.4.2 | |
372 | ||
35ed393e | 373 | The above examples can be used with any application supporting library |
7b68c30d DSH |
374 | configuration if "openssl_conf" is modified to match the appropriate "appname". |
375 | ||
376 | For example if the second sample file above is saved to "example.cnf" then | |
377 | the command line: | |
378 | ||
379 | OPENSSL_CONF=example.cnf openssl asn1parse -genstr OID:1.2.3.4.1 | |
380 | ||
381 | will output: | |
382 | ||
383 | 0:d=0 hl=2 l= 4 prim: OBJECT :newoid1 | |
384 | ||
385 | showing that the OID "newoid1" has been added as "1.2.3.4.1". | |
386 | ||
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387 | =head1 BUGS |
388 | ||
389 | Currently there is no way to include characters using the octal B<\nnn> | |
390 | form. Strings are all null terminated so nulls cannot form part of | |
391 | the value. | |
392 | ||
393 | The escaping isn't quite right: if you want to use sequences like B<\n> | |
394 | you can't use any quote escaping on the same line. | |
395 | ||
396 | Files are loaded in a single pass. This means that an variable expansion | |
397 | will only work if the variables referenced are defined earlier in the | |
398 | file. | |
399 | ||
400 | =head1 SEE ALSO | |
401 | ||
9b86974e | 402 | L<x509(1)>, L<req(1)>, L<ca(1)> |
aba3e65f | 403 | |
e2f92610 RS |
404 | =head1 COPYRIGHT |
405 | ||
406 | Copyright 2000-2016 The OpenSSL Project Authors. All Rights Reserved. | |
407 | ||
408 | Licensed under the OpenSSL license (the "License"). You may not use | |
409 | this file except in compliance with the License. You can obtain a copy | |
410 | in the file LICENSE in the source distribution or at | |
411 | L<https://www.openssl.org/source/license.html>. | |
412 | ||
413 | =cut |