5 config - OpenSSL CONF library configuration files
9 The OpenSSL CONF library can be used to read configuration files.
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
12 files for the B<x509> utility. OpenSSL applications can also use the
13 CONF library for their own purposes.
15 A configuration file is divided into a number of sections. Each section
16 starts with a line C<[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. The brackets are required.
20 The first section of a configuration file is special and is referred
21 to as the B<default> section. This section is usually unnamed and spans 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
26 The environment is mapped onto a section called B<ENV>.
28 Comments can be included by preceding them with the B<#> character
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
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. The environment variable B<OPENSSL_CONF_INCLUDE> can also be
44 used to specify the path to prepend to all .include paths.
46 There can be optional B<=> character and whitespace characters between
47 B<.include> directive and the path which can be useful in cases the
48 configuration file needs to be loaded by old OpenSSL versions which do
49 not support the B<.include> syntax. They would bail out with error
50 if the B<=> character is not present but with it they just ignore
53 Pragmas can be specified with the B<.pragma> directive.
54 See L</PRAGMAS> for mor information.
56 Each section in a configuration file consists of a number of name and
57 value pairs of the form B<name=value>
59 The B<name> string can contain any alphanumeric characters as well as
60 a few punctuation symbols such as B<.> B<,> B<;> and B<_>.
62 The B<value> string consists of the string following the B<=> character
63 until end of line with any leading and trailing white space removed.
65 The value string undergoes variable expansion. This can be done by
66 including the form B<$var> or B<${var}>: this will substitute the value
67 of the named variable in the current section. It is also possible to
68 substitute a value from another section using the syntax B<$section::name>
69 or B<${section::name}>. By using the form B<$ENV::name> environment
70 variables can be substituted. It is also possible to assign values to
71 environment variables by using the name B<ENV::name>, this will work
72 if the program looks up environment variables using the B<CONF> library
73 instead of calling getenv() directly. The value string must not exceed 64k in
74 length after variable expansion. Otherwise an error will occur.
76 It is possible to escape certain characters by using any kind of quote
77 or the B<\> character. By making the last character of a line a B<\>
78 a B<value> string can be spread across multiple lines. In addition
79 the sequences B<\n>, B<\r>, B<\b> and B<\t> are recognized.
81 All expansion and escape rules as described above that apply to B<value>
82 also apply to the path of the B<.include> directive.
86 Pragmas can be used to change the behavior of the configuration file
87 parser, among others. Currently supported pragmas are:
91 =item B<.pragma> B<dollarid>:I<value>
93 I<value> can be one of:
97 =item B<"on"> or B<"true">
99 this signifies that dollar signs are considered an identity character
100 from this point on and that variable expansion requires the use of
101 braces or parentheses. In other words, C<foo$bar> will be considered
102 a name instead of C<foo> followed by the expansion of the variable
104 This is suitable for platforms where the dollar sign is commonly used
107 =item B<"off"> or B<"false">
109 Turns this pragma off, i.e. C<foo$bar> will be interpreted as C<foo>
110 followed by the expansion of the variable C<bar>.
114 By default, this pragma is turned off.
118 =head1 OPENSSL LIBRARY CONFIGURATION
120 Applications can automatically configure certain
121 aspects of OpenSSL using the master OpenSSL configuration file, or optionally
122 an alternative configuration file. The B<openssl> utility includes this
123 functionality: any sub command uses the master OpenSSL configuration file
124 unless an option is used in the sub command to use an alternative configuration
127 To enable library configuration the default section needs to contain an
128 appropriate line which points to the main configuration section. The default
129 name is B<openssl_conf> which is used by the B<openssl> utility. Other
130 applications may use an alternative name such as B<myapplication_conf>.
131 All library configuration lines appear in the default section at the start
132 of the configuration file.
134 The configuration section should consist of a set of name value pairs which
135 contain specific module configuration information. The B<name> represents
136 the name of the I<configuration module>. The meaning of the B<value> is
137 module specific: it may, for example, represent a further configuration
138 section containing configuration module specific information. E.g.:
140 # This must be in the default section
141 openssl_conf = openssl_init
145 oid_section = new_oids
146 engines = engine_section
147 providers = provider_section
151 ... new oids here ...
155 ... engine stuff here ...
159 ... provider stuff here ...
161 The features of each configuration module are described below.
163 =head2 ASN1 Object Configuration Module
165 This module has the name B<oid_section>. The value of this variable points
166 to a section containing name value pairs of OIDs: the name is the OID short
167 and long name, the value is the numerical form of the OID. Although some of
168 the B<openssl> utility sub commands already have their own ASN1 OBJECT section
169 functionality not all do. By using the ASN1 OBJECT configuration module
170 B<all> the B<openssl> utility sub commands can see the new objects as well
171 as any compliant applications. For example:
175 some_new_oid = 1.2.3.4
176 some_other_oid = 1.2.3.5
178 It is also possible to set the value to the long name followed
179 by a comma and the numerical OID form. For example:
181 shortName = some object long name, 1.2.3.4
183 =head2 Engine Configuration Module
185 This ENGINE configuration module has the name B<engines>. The value of this
186 variable points to a section containing further ENGINE configuration
189 The section pointed to by B<engines> is a table of engine names (though see
190 B<engine_id> below) and further sections containing configuration information
191 specific to each ENGINE.
193 Each ENGINE specific section is used to set default algorithms, load
194 dynamic, perform initialization and send ctrls. The actual operation performed
195 depends on the I<command> name which is the name of the name value pair. The
196 currently supported commands are listed below.
202 # Configure ENGINE named "foo"
204 # Configure ENGINE named "bar"
208 ... foo ENGINE specific commands ...
211 ... "bar" ENGINE specific commands ...
213 The command B<engine_id> is used to give the ENGINE name. If used this
214 command must be first. For example:
217 # This would normally handle an ENGINE named "foo"
221 # Override default name and use "myfoo" instead.
224 The command B<dynamic_path> loads and adds an ENGINE from the given path. It
225 is equivalent to sending the ctrls B<SO_PATH> with the path argument followed
226 by B<LIST_ADD> with value 2 and B<LOAD> to the dynamic ENGINE. If this is
227 not the required behaviour then alternative ctrls can be sent directly
228 to the dynamic ENGINE using ctrl commands.
230 The command B<init> determines whether to initialize the ENGINE. If the value
231 is B<0> the ENGINE will not be initialized, if B<1> and attempt it made to
232 initialized the ENGINE immediately. If the B<init> command is not present
233 then an attempt will be made to initialize the ENGINE after all commands in
234 its section have been processed.
236 The command B<default_algorithms> sets the default algorithms an ENGINE will
237 supply using the functions ENGINE_set_default_string().
239 If the name matches none of the above command names it is assumed to be a
240 ctrl command which is sent to the ENGINE. The value of the command is the
241 argument to the ctrl command. If the value is the string B<EMPTY> then no
242 value is sent to the command.
249 # Configure ENGINE named "foo"
253 # Load engine from DSO
254 dynamic_path = /some/path/fooengine.so
255 # A foo specific ctrl.
256 some_ctrl = some_value
257 # Another ctrl that doesn't take a value.
259 # Supply all default algorithms
260 default_algorithms = ALL
262 =head2 Provider Configuration Module
264 This provider configuration module has the name B<providers>. The
265 value of this variable points to a section containing further provider
266 configuration information.
268 The section pointed to by B<providers> is a table of provider names
269 (though see B<identity> below) and further sections containing
270 configuration information specific to each provider module.
272 Each provider specific section is used to load its module, perform
273 activation and set parameters to pass to the provider on demand. The
274 actual operation performed depends on the name of the name value pair.
275 The currently supported commands are listed below.
281 # Configure provider named "foo"
283 # Configure provider named "bar"
287 ... "foo" provider specific parameters ...
290 ... "bar" provider specific parameters ...
292 The command B<identity> is used to give the provider name. For example:
295 # This would normally handle a provider named "foo"
299 # Override default name and use "myfoo" instead.
302 The parameter B<module> loads and adds a provider module from the
303 given module path. That path may be a simple filename, a relative
304 path or an absolute path.
306 The parameter B<activate> determines whether to activate the
307 provider. The value has no importance, the presence of the parameter
308 is enough for activation to take place.
310 All parameters in the section as well as sub-sections are made
311 available to the provider.
313 =head2 EVP Configuration Module
315 This module has the name B<alg_section> which points to a section containing
318 The supported algorithm commands are:
322 =item B<default_properties>
324 The value may be anything that is acceptable as a property query
325 string for EVP_set_default_properties().
327 =item B<fips_mode> (deprecated)
329 The value is a boolean that can be B<yes> or B<no>. If the value is
330 B<yes>, this is exactly equivalent to:
332 default_properties = fips=yes
334 If the value is B<no>, nothing happens.
338 These two commands should not be used together, as there is no control
339 over how they affect each other.
340 The use of B<fips_mode> is strongly discouraged and is only present
341 for backward compatibility with earlier OpenSSL FIPS modules.
343 =head2 SSL Configuration Module
345 This module has the name B<ssl_conf> which points to a section containing
348 Each line in the SSL configuration section contains the name of the
349 configuration and the section containing it.
351 Each configuration section consists of command value pairs for B<SSL_CONF>.
352 Each pair will be passed to a B<SSL_CTX> or B<SSL> structure if it calls
353 SSL_CTX_config() or SSL_config() with the appropriate configuration name.
355 Note: any characters before an initial dot in the configuration section are
356 ignored so the same command can be used multiple times.
364 server = server_section
368 RSA.Certificate = server-rsa.pem
369 ECDSA.Certificate = server-ecdsa.pem
372 The system default configuration with name B<system_default> if present will
373 be applied during any creation of the B<SSL_CTX> structure.
375 Example of a configuration with the system default:
381 system_default = system_default_sect
383 [system_default_sect]
385 MinProtocol = TLSv1.2
390 If a configuration file attempts to expand a variable that doesn't exist
391 then an error is flagged and the file will not load. This can happen
392 if an attempt is made to expand an environment variable that doesn't
393 exist. For example in a previous version of OpenSSL the default OpenSSL
394 master configuration file used the value of B<HOME> which may not be
395 defined on non Unix systems and would cause an error.
397 This can be worked around by including a B<default> section to provide
398 a default value: then if the environment lookup fails the default value
399 will be used instead. For this to work properly the default value must
400 be defined earlier in the configuration file than the expansion. See
401 the B<EXAMPLES> section for an example of how to do this.
403 If the same variable exists in the same section then all but the last
404 value will be silently ignored. In certain circumstances such as with
405 DNs the same field may occur multiple times. This is usually worked
406 around by ignoring any characters before an initial B<.> e.g.
413 Here is a sample configuration file using some of the features
416 # This is the default section.
419 configdir=$ENV::HOME/config
423 # We are now in section one.
425 # Quotes permit leading and trailing whitespace
426 any = " any variable name "
428 other = A string that can \
429 cover several lines \
430 by including \\ characters
432 message = Hello World\n
436 greeting = $section_one::message
438 This next example shows how to expand environment variables safely.
440 Suppose you want a variable called B<tmpfile> to refer to a
441 temporary filename. The directory it is placed in can determined by
442 the B<TEMP> or B<TMP> environment variables but they may not be
443 set to any value at all. If you just include the environment variable
444 names and the variable doesn't exist then this will cause an error when
445 an attempt is made to load the configuration file. By making use of the
446 default section both values can be looked up with B<TEMP> taking
447 priority and B</tmp> used if neither is defined:
450 # The above value is used if TMP isn't in the environment
452 # The above value is used if TEMP isn't in the environment
453 tmpfile=${ENV::TEMP}/tmp.filename
455 Simple OpenSSL library configuration example to enter FIPS mode:
457 # Default appname: should match "appname" parameter (if any)
458 # supplied to CONF_modules_load_file et al.
459 openssl_conf = openssl_conf_section
461 [openssl_conf_section]
462 # Configuration module list
463 alg_section = evp_sect
466 # Set to "yes" to enter FIPS mode if supported
469 Note: in the above example you will get an error in non FIPS capable versions
472 More complex OpenSSL library configuration. Add OID and don't enter FIPS mode:
474 # Default appname: should match "appname" parameter (if any)
475 # supplied to CONF_modules_load_file et al.
476 openssl_conf = openssl_conf_section
478 [openssl_conf_section]
479 # Configuration module list
480 alg_section = evp_sect
481 oid_section = new_oids
484 # This will have no effect as FIPS mode is off by default.
485 # Set to "yes" to enter FIPS mode, if supported
489 # New OID, just short name
491 # New OID shortname and long name
492 newoid2 = New OID 2 long name, 1.2.3.4.2
494 The above examples can be used with any application supporting library
495 configuration if "openssl_conf" is modified to match the appropriate "appname".
497 For example if the second sample file above is saved to "example.cnf" then
500 OPENSSL_CONF=example.cnf openssl asn1parse -genstr OID:1.2.3.4.1
504 0:d=0 hl=2 l= 4 prim: OBJECT :newoid1
506 showing that the OID "newoid1" has been added as "1.2.3.4.1".
512 =item B<OPENSSL_CONF>
514 The path to the config file.
515 Ignored in set-user-ID and set-group-ID programs.
517 =item B<OPENSSL_ENGINES>
519 The path to the engines directory.
520 Ignored in set-user-ID and set-group-ID programs.
522 =item B<OPENSSL_MODULES>
524 The path to the directory with OpenSSL modules, such as providers.
525 Ignored in set-user-ID and set-group-ID programs.
527 =item B<OPENSSL_CONF_INCLUDE>
529 The optional path to prepend to all .include paths.
535 Currently there is no way to include characters using the octal B<\nnn>
536 form. Strings are all null terminated so nulls cannot form part of
539 The escaping isn't quite right: if you want to use sequences like B<\n>
540 you can't use any quote escaping on the same line.
542 Files are loaded in a single pass. This means that an variable expansion
543 will only work if the variables referenced are defined earlier in the
548 An undocumented API, NCONF_WIN32(), used a slightly different set
549 of parsing rules there were intended to be tailored to
550 the Microsoft Windows platform.
551 Specifically, the backslash character was not an escape character and
552 could be used in pathnames, only the double-quote character was recognized,
553 and comments began with a semi-colon.
554 This function was deprecated in OpenSSL 3.0; applications with
555 configuration files using that syntax will have to be modified.
559 L<openssl-x509(1)>, L<openssl-req(1)>, L<openssl-ca(1)>, L<fips_config(5)>
563 Copyright 2000-2018 The OpenSSL Project Authors. All Rights Reserved.
565 Licensed under the Apache License 2.0 (the "License"). You may not use
566 this file except in compliance with the License. You can obtain a copy
567 in the file LICENSE in the source distribution or at
568 L<https://www.openssl.org/source/license.html>.