3 =for comment openssl_manual_section:5
7 config - OpenSSL CONF library configuration files
11 The OpenSSL CONF library can be used to read configuration files.
12 It is used for the OpenSSL master configuration file B<openssl.cnf>
13 and in a few other places like B<SPKAC> files and certificate extension
14 files for the B<x509> utility. OpenSSL applications can also use the
15 CONF library for their own purposes.
17 A configuration file is divided into a number of sections. Each section
18 starts with a line B<[ section_name ]> and ends when a new section is
19 started or end of file is reached. A section name can consist of
20 alphanumeric characters and underscores.
22 The first section of a configuration file is special and is referred
23 to as the B<default> section this is usually unnamed and is from the
24 start of file until the first named section. When a name is being looked up
25 it is first looked up in a named section (if any) and then the
28 The environment is mapped onto a section called B<ENV>.
30 Comments can be included by preceding them with the B<#> character
32 Each section in a configuration file consists of a number of name and
33 value pairs of the form B<name=value>
35 The B<name> string can contain any alphanumeric characters as well as
36 a few punctuation symbols such as B<.> B<,> B<;> and B<_>.
38 The B<value> string consists of the string following the B<=> character
39 until end of line with any leading and trailing white space removed.
41 The value string undergoes variable expansion. This can be done by
42 including the form B<$var> or B<${var}>: this will substitute the value
43 of the named variable in the current section. It is also possible to
44 substitute a value from another section using the syntax B<$section::name>
45 or B<${section::name}>. By using the form B<$ENV::name> environment
46 variables can be substituted. It is also possible to assign values to
47 environment variables by using the name B<ENV::name>, this will work
48 if the program looks up environment variables using the B<CONF> library
49 instead of calling getenv() directly.
51 It is possible to escape certain characters by using any kind of quote
52 or the B<\> character. By making the last character of a line a B<\>
53 a B<value> string can be spread across multiple lines. In addition
54 the sequences B<\n>, B<\r>, B<\b> and B<\t> are recognized.
56 =head1 OPENSSL LIBRARY CONFIGURATION
58 Applications can automatically configure certain
59 aspects of OpenSSL using the master OpenSSL configuration file, or optionally
60 an alternative configuration file. The B<openssl> utility includes this
61 functionality: any sub command uses the master OpenSSL configuration file
62 unless an option is used in the sub command to use an alternative configuration
65 To enable library configuration the default section needs to contain an
66 appropriate line which points to the main configuration section. The default
67 name is B<openssl_conf> which is used by the B<openssl> utility. Other
68 applications may use an alternative name such as B<myapplicaton_conf>.
70 The configuration section should consist of a set of name value pairs which
71 contain specific module configuration information. The B<name> represents
72 the name of the I<configuration module> the meaning of the B<value> is
73 module specific: it may, for example, represent a further configuration
74 section containing configuration module specific information. E.g.
76 openssl_conf = openssl_init
80 oid_section = new_oids
81 engines = engine_section
89 ... engine stuff here ...
91 The features of each configuration module are described below.
93 =head2 ASN1 Object Configuration Module
95 This module has the name B<oid_section>. The value of this variable points
96 to a section containing name value pairs of OIDs: the name is the OID short
97 and long name, the value is the numerical form of the OID. Although some of
98 the B<openssl> utility sub commands already have their own ASN1 OBJECT section
99 functionality not all do. By using the ASN1 OBJECT configuration module
100 B<all> the B<openssl> utility sub commands can see the new objects as well
101 as any compliant applications. For example:
105 some_new_oid = 1.2.3.4
106 some_other_oid = 1.2.3.5
108 It is also possible to set the value to the long name followed
109 by a comma and the numerical OID form. For example:
111 shortName = some object long name, 1.2.3.4
113 =head2 Engine Configuration Module
115 This ENGINE configuration module has the name B<engines>. The value of this
116 variable points to a section containing further ENGINE configuration
119 The section pointed to by B<engines> is a table of engine names (though see
120 B<engine_id> below) and further sections containing configuration information
121 specific to each ENGINE.
123 Each ENGINE specific section is used to set default algorithms, load
124 dynamic, perform initialization and send ctrls. The actual operation performed
125 depends on the I<command> name which is the name of the name value pair. The
126 currently supported commands are listed below.
132 # Configure ENGINE named "foo"
134 # Configure ENGINE named "bar"
138 ... foo ENGINE specific commands ...
141 ... "bar" ENGINE specific commands ...
143 The command B<engine_id> is used to give the ENGINE name. If used this
144 command must be first. For example:
147 # This would normally handle an ENGINE named "foo"
151 # Override default name and use "myfoo" instead.
154 The command B<dynamic_path> loads and adds an ENGINE from the given path. It
155 is equivalent to sending the ctrls B<SO_PATH> with the path argument followed
156 by B<LIST_ADD> with value 2 and B<LOAD> to the dynamic ENGINE. If this is
157 not the required behaviour then alternative ctrls can be sent directly
158 to the dynamic ENGINE using ctrl commands.
160 The command B<init> determines whether to initialize the ENGINE. If the value
161 is B<0> the ENGINE will not be initialized, if B<1> and attempt it made to
162 initialized the ENGINE immediately. If the B<init> command is not present
163 then an attempt will be made to initialize the ENGINE after all commands in
164 its section have been processed.
166 The command B<default_algorithms> sets the default algorithms an ENGINE will
167 supply using the functions ENGINE_set_default_string().
169 If the name matches none of the above command names it is assumed to be a
170 ctrl command which is sent to the ENGINE. The value of the command is the
171 argument to the ctrl command. If the value is the string B<EMPTY> then no
172 value is sent to the command.
179 # Configure ENGINE named "foo"
183 # Load engine from DSO
184 dynamic_path = /some/path/fooengine.so
185 # A foo specific ctrl.
186 some_ctrl = some_value
187 # Another ctrl that doesn't take a value.
189 # Supply all default algorithms
190 default_algorithms = ALL
192 =head2 EVP Configuration Module
194 This modules has the name B<alg_section> which points to a section containing
197 Currently the only algorithm command supported is B<fips_mode> whose
198 value should be a boolean string such as B<on> or B<off>. If the value is
199 B<on> this attempt to enter FIPS mode. If the call fails or the library is
200 not FIPS capable then an error occurs.
204 alg_section = evp_settings
210 =head2 SSL Configuration Module
212 This module has the name B<ssl_conf> which points to a section containing
215 Each line in the SSL configuration section contains the name of the
216 configuration and the section containing it.
218 Each configuration section consists of command value pairs for B<SSL_CONF>.
219 Each pair will be passed to a B<SSL_CTX> or B<SSL> structure if it calls
220 SSL_CTX_config() or SSL_config() with the appropriate configuration name.
222 Note: any characters before an initial dot in the configuration section are
223 ignored so the same command can be used multiple times.
231 server = server_section
235 RSA.Certificate = server-rsa.pem
236 ECDSA.Certificate = server-ecdsa.pem
241 If a configuration file attempts to expand a variable that doesn't exist
242 then an error is flagged and the file will not load. This can happen
243 if an attempt is made to expand an environment variable that doesn't
244 exist. For example in a previous version of OpenSSL the default OpenSSL
245 master configuration file used the value of B<HOME> which may not be
246 defined on non Unix systems and would cause an error.
248 This can be worked around by including a B<default> section to provide
249 a default value: then if the environment lookup fails the default value
250 will be used instead. For this to work properly the default value must
251 be defined earlier in the configuration file than the expansion. See
252 the B<EXAMPLES> section for an example of how to do this.
254 If the same variable exists in the same section then all but the last
255 value will be silently ignored. In certain circumstances such as with
256 DNs the same field may occur multiple times. This is usually worked
257 around by ignoring any characters before an initial B<.> e.g.
264 Here is a sample configuration file using some of the features
267 # This is the default section.
270 RANDFILE= ${ENV::HOME}/.rnd
271 configdir=$ENV::HOME/config
275 # We are now in section one.
277 # Quotes permit leading and trailing whitespace
278 any = " any variable name "
280 other = A string that can \
281 cover several lines \
282 by including \\ characters
284 message = Hello World\n
288 greeting = $section_one::message
290 This next example shows how to expand environment variables safely.
292 Suppose you want a variable called B<tmpfile> to refer to a
293 temporary filename. The directory it is placed in can determined by
294 the B<TEMP> or B<TMP> environment variables but they may not be
295 set to any value at all. If you just include the environment variable
296 names and the variable doesn't exist then this will cause an error when
297 an attempt is made to load the configuration file. By making use of the
298 default section both values can be looked up with B<TEMP> taking
299 priority and B</tmp> used if neither is defined:
302 # The above value is used if TMP isn't in the environment
304 # The above value is used if TEMP isn't in the environment
305 tmpfile=${ENV::TEMP}/tmp.filename
307 Simple OpenSSL library configuration example to enter FIPS mode:
309 # Default appname: should match "appname" parameter (if any)
310 # supplied to CONF_modules_load_file et al.
311 openssl_conf = openssl_conf_section
313 [openssl_conf_section]
314 # Configuration module list
315 alg_section = evp_sect
318 # Set to "yes" to enter FIPS mode if supported
321 Note: in the above example you will get an error in non FIPS capable versions
324 More complex OpenSSL library configuration. Add OID and don't enter FIPS mode:
326 # Default appname: should match "appname" parameter (if any)
327 # supplied to CONF_modules_load_file et al.
328 openssl_conf = openssl_conf_section
330 [openssl_conf_section]
331 # Configuration module list
332 alg_section = evp_sect
333 oid_section = new_oids
336 # This will have no effect as FIPS mode is off by default.
337 # Set to "yes" to enter FIPS mode, if supported
341 # New OID, just short name
343 # New OID shortname and long name
344 newoid2 = New OID 2 long name, 1.2.3.4.2
346 The above examples can be used with any application supporting library
347 configuration if "openssl_conf" is modified to match the appropriate "appname".
349 For example if the second sample file above is saved to "example.cnf" then
352 OPENSSL_CONF=example.cnf openssl asn1parse -genstr OID:1.2.3.4.1
356 0:d=0 hl=2 l= 4 prim: OBJECT :newoid1
358 showing that the OID "newoid1" has been added as "1.2.3.4.1".
362 Currently there is no way to include characters using the octal B<\nnn>
363 form. Strings are all null terminated so nulls cannot form part of
366 The escaping isn't quite right: if you want to use sequences like B<\n>
367 you can't use any quote escaping on the same line.
369 Files are loaded in a single pass. This means that an variable expansion
370 will only work if the variables referenced are defined earlier in the
375 L<x509(1)>, L<req(1)>, L<ca(1)>
379 Copyright 2000-2016 The OpenSSL Project Authors. All Rights Reserved.
381 Licensed under the OpenSSL license (the "License"). You may not use
382 this file except in compliance with the License. You can obtain a copy
383 in the file LICENSE in the source distribution or at
384 L<https://www.openssl.org/source/license.html>.