/usr/man/cat.5/config.5(/usr/man/cat.5/config.5)



CONFIG(5)                    OpenSSL                    CONFIG(5)

NAME

     config - OpenSSL CONF library configuration files

DESCRIPTION

     The OpenSSL CONF library can be used to read configuration
     files.  It is used for the OpenSSL master configuration file
     openssl.cnf and in a few other places like SPKAC files and
     certificate extension files for the x509 utility. OpenSSL
     applications can also use the CONF library for their own
     purposes.

     A configuration file is divided into a number of sections.
     Each section starts with a line [ section_name ] and ends
     when a new section is started or end of file is reached. A
     section name can consist of alphanumeric characters and
     underscores.

     The first section of a configuration file is special and is
     referred to as the default section. This section is usually
     unnamed and spans from the start of file until the first
     named section. When a name is being looked up it is first
     looked up in a named section (if any) and then the default
     section.

     The environment is mapped onto a section called ENV.

     Comments can be included by preceding them with the #
     character

     Each section in a configuration file consists of a number of
     name and value pairs of the form name=value

     The name string can contain any alphanumeric characters as
     well as a few punctuation symbols such as . , ; and _.

     The value string consists of the string following the =
     character until end of line with any leading and trailing
     white space removed.

     The value string undergoes variable expansion. This can be
     done by including the form $var or ${var}: this will
     substitute the value of the named variable in the current
     section. It is also possible to substitute a value from
     another section using the syntax $section::name or
     ${section::name}. By using the form $ENV::name environment
     variables can be substituted. It is also possible to assign
     values to environment variables by using the name ENV::name,
     this will work if the program looks up environment variables
     using the CONF library instead of calling ggeetteennvv(()) directly.
     The value string must not exceed 64k in length after
     variable expansion. Otherwise an error will occur.

1.0.2t               Last change: 2019-09-10                    1

CONFIG(5)                    OpenSSL                    CONFIG(5)

     It is possible to escape certain characters by using any
     kind of quote or the \ character. By making the last
     character of a line a \ a value string can be spread across
     multiple lines. In addition the sequences \n, \r, \b and \t
     are recognized.

OPENSSL LIBRARY CONFIGURATION
In OpenSSL 0.9.7 and later applications can automatically configure certain aspects of OpenSSL using the master OpenSSL configuration file, or optionally an alternative configuration file. The openssl utility includes this functionality: any sub command uses the master OpenSSL configuration file unless an option is used in the sub command to use an alternative configuration file. To enable library configuration the default section needs to contain an appropriate line which points to the main configuration section. The default name is openssl_conf which is used by the openssl utility. Other applications may use an alternative name such as myapplicaton_conf. The configuration section should consist of a set of name value pairs which contain specific module configuration information. The name represents the name of the configuration module the meaning of the value is module specific: it may, for example, represent a further configuration section containing configuration module specific information. E.g. openssl_conf = openssl_init [openssl_init] oid_section = new_oids engines = engine_section [new_oids] ... new oids here ... [engine_section] ... engine stuff here ... The features of each configuration module are described below. ASN1 OBJECT CONFIGURATION MODULE This module has the name oid_section. The value of this variable points to a section containing name value pairs of OIDs: the name is the OID short and long name, the value is 1.0.2t Last change: 2019-09-10 2 CONFIG(5) OpenSSL CONFIG(5) the numerical form of the OID. Although some of the openssl utility sub commands already have their own ASN1 OBJECT section functionality not all do. By using the ASN1 OBJECT configuration module all the openssl utility sub commands can see the new objects as well as any compliant applications. For example: [new_oids] some_new_oid = 1.2.3.4 some_other_oid = 1.2.3.5 In OpenSSL 0.9.8 it is also possible to set the value to the long name followed by a comma and the numerical OID form. For example: shortName = some object long name, 1.2.3.4 ENGINE CONFIGURATION MODULE This ENGINE configuration module has the name engines. The value of this variable points to a section containing further ENGINE configuration information. The section pointed to by engines is a table of engine names (though see engine_id below) and further sections containing configuration information specific to each ENGINE. Each ENGINE specific section is used to set default algorithms, load dynamic, perform initialization and send ctrls. The actual operation performed depends on the command name which is the name of the name value pair. The currently supported commands are listed below. For example: [engine_section] # Configure ENGINE named "foo" foo = foo_section # Configure ENGINE named "bar" bar = bar_section [foo_section] ... foo ENGINE specific commands ... [bar_section] ... "bar" ENGINE specific commands ... The command engine_id is used to give the ENGINE name. If used this command must be first. For example: 1.0.2t Last change: 2019-09-10 3 CONFIG(5) OpenSSL CONFIG(5) [engine_section] # This would normally handle an ENGINE named "foo" foo = foo_section [foo_section] # Override default name and use "myfoo" instead. engine_id = myfoo The command dynamic_path loads and adds an ENGINE from the given path. It is equivalent to sending the ctrls SO_PATH with the path argument followed by LIST_ADD with value 2 and LOAD to the dynamic ENGINE. If this is not the required behaviour then alternative ctrls can be sent directly to the dynamic ENGINE using ctrl commands. The command init determines whether to initialize the ENGINE. If the value is 0 the ENGINE will not be initialized, if 1 and attempt it made to initialized the ENGINE immediately. If the init command is not present then an attempt will be made to initialize the ENGINE after all commands in its section have been processed. The command default_algorithms sets the default algorithms an ENGINE will supply using the functions EENNGGIINNEE_sseett_ddeeffaauulltt_ssttrriinngg(()) If the name matches none of the above command names it is assumed to be a ctrl command which is sent to the ENGINE. The value of the command is the argument to the ctrl command. If the value is the string EMPTY then no value is sent to the command. For example: [engine_section] # Configure ENGINE named "foo" foo = foo_section [foo_section] # Load engine from DSO dynamic_path = /some/path/fooengine.so # A foo specific ctrl. some_ctrl = some_value # Another ctrl that doesn't take a value. other_ctrl = EMPTY # Supply all default algorithms default_algorithms = ALL 1.0.2t Last change: 2019-09-10 4 CONFIG(5) OpenSSL CONFIG(5) EVP CONFIGURATION MODULE This modules has the name alg_section which points to a section containing algorithm commands. Currently the only algorithm command supported is fips_mode whose value should be a boolean string such as on or off. If the value is on this attempt to enter FIPS mode. If the call fails or the library is not FIPS capable then an error occurs. For example: alg_section = evp_settings [evp_settings] fips_mode = on

NOTES
If a configuration file attempts to expand a variable that doesn't exist then an error is flagged and the file will not load. This can happen if an attempt is made to expand an environment variable that doesn't exist. For example in a previous version of OpenSSL the default OpenSSL master configuration file used the value of HOME which may not be defined on non Unix systems and would cause an error. This can be worked around by including a default section to provide a default value: then if the environment lookup fails the default value will be used instead. For this to work properly the default value must be defined earlier in the configuration file than the expansion. See the EXAMPLES section for an example of how to do this. If the same variable exists in the same section then all but the last value will be silently ignored. In certain circumstances such as with DNs the same field may occur multiple times. This is usually worked around by ignoring any characters before an initial . e.g. 1.OU="My first OU" 2.OU="My Second OU"

EXAMPLES
Here is a sample configuration file using some of the features mentioned above. # This is the default section. 1.0.2t Last change: 2019-09-10 5 CONFIG(5) OpenSSL CONFIG(5) HOME=/temp RANDFILE= ${ENV::HOME}/.rnd configdir=$ENV::HOME/config [ section_one ] # We are now in section one. # Quotes permit leading and trailing whitespace any = " any variable name " other = A string that can \ cover several lines \ by including \\ characters message = Hello World\n [ section_two ] greeting = $section_one::message This next example shows how to expand environment variables safely. Suppose you want a variable called tmpfile to refer to a temporary filename. The directory it is placed in can determined by the the TEMP or TMP environment variables but they may not be set to any value at all. If you just include the environment variable names and the variable doesn't exist then this will cause an error when an attempt is made to load the configuration file. By making use of the default section both values can be looked up with TEMP taking priority and /tmp used if neither is defined: TMP=/tmp # The above value is used if TMP isn't in the environment TEMP=$ENV::TMP # The above value is used if TEMP isn't in the environment tmpfile=${ENV::TEMP}/tmp.filename Simple OpenSSL library configuration example to enter FIPS mode: # Default appname: should match "appname" parameter (if any) # supplied to CONF_modules_load_file et al. openssl_conf = openssl_conf_section [openssl_conf_section] # Configuration module list alg_section = evp_sect 1.0.2t Last change: 2019-09-10 6 CONFIG(5) OpenSSL CONFIG(5) [evp_sect] # Set to "yes" to enter FIPS mode if supported fips_mode = yes Note: in the above example you will get an error in non FIPS capable versions of OpenSSL. More complex OpenSSL library configuration. Add OID and don't enter FIPS mode: # Default appname: should match "appname" parameter (if any) # supplied to CONF_modules_load_file et al. openssl_conf = openssl_conf_section [openssl_conf_section] # Configuration module list alg_section = evp_sect oid_section = new_oids [evp_sect] # This will have no effect as FIPS mode is off by default. # Set to "yes" to enter FIPS mode, if supported fips_mode = no [new_oids] # New OID, just short name newoid1 = 1.2.3.4.1 # New OID shortname and long name newoid2 = New OID 2 long name, 1.2.3.4.2 The above examples can be used with with any application supporting library configuration if "openssl_conf" is modified to match the appropriate "appname". For example if the second sample file above is saved to "example.cnf" then the command line: OPENSSL_CONF=example.cnf openssl asn1parse -genstr OID:1.2.3.4.1 will output: 0:d=0 hl=2 l= 4 prim: OBJECT :newoid1 showing that the OID "newoid1" has been added as "1.2.3.4.1".

BUGS
Currently there is no way to include characters using the octal \nnn form. Strings are all null terminated so nulls cannot form part of the value. 1.0.2t Last change: 2019-09-10 7 CONFIG(5) OpenSSL CONFIG(5) The escaping isn't quite right: if you want to use sequences like \n you can't use any quote escaping on the same line. Files are loaded in a single pass. This means that an variable expansion will only work if the variables referenced are defined earlier in the file.

SEE ALSO
x509(1), req(1), ca(1) 1.0.2t Last change: 2019-09-10 8

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