bionic (5) config.5ssl.gz

Provided by: openssl_1.1.1-1ubuntu2.1~18.04.23_amd64 bug

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

       Other files can be included using the .include directive followed by a path. If the path points to a
       directory all files with names ending with .cnf or .conf are included from the directory.  Recursive
       inclusion of directories from files in such directory is not supported. That means the files in the
       included directory can also contain .include directives but only inclusion of regular files is supported
       there. The inclusion of directories is not supported on systems without POSIX IO support.

       It is strongly recommended to use absolute paths with the .include directive. Relative paths are
       evaluated based on the application current working directory so unless the configuration file containing
       the .include directive is application specific the inclusion will not work as expected.

       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 getenv() directly. The value string must not exceed
       64k in length after variable expansion. Otherwise an error will occur.

       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.

       All expansion and escape rules as described above that apply to value also apply to the path of the
       .include directive.

OPENSSL LIBRARY CONFIGURATION

       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 myapplication_conf.  All library configuration
       lines appear in the default section at the start of the configuration file.

       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.:

        # This must be in the default section
        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 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

       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:

        [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
       ENGINE_set_default_string().

       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

   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 can only be the boolean string
       off. If fips_mode is set to on, an error occurs as this library version is not FIPS capable.

   SSL Configuration Module
       This module has the name ssl_conf which points to a section containing SSL configurations.

       Each line in the SSL configuration section contains the name of the configuration and the section
       containing it.

       Each configuration section consists of command value pairs for SSL_CONF.  Each pair will be passed to a
       SSL_CTX or SSL structure if it calls SSL_CTX_config() or SSL_config() with the appropriate configuration
       name.

       Note: any characters before an initial dot in the configuration section are ignored so the same command
       can be used multiple times.

       For example:

        ssl_conf = ssl_sect

        [ssl_sect]

        server = server_section

        [server_section]

        RSA.Certificate = server-rsa.pem
        ECDSA.Certificate = server-ecdsa.pem
        Ciphers = ALL:!RC4

       The system default configuration with name system_default if present will be applied during any creation
       of the SSL_CTX structure.

       Example of a configuration with the system default:

        ssl_conf = ssl_sect

        [ssl_sect]

        system_default = system_default_sect

        [system_default_sect]

        MinProtocol = TLSv1.2

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.

        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 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

        [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 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".

ENVIRONMENT

       OPENSSL_CONF
           The path to the config file.  Ignored in set-user-ID and set-group-ID programs.

       OPENSSL_ENGINES
           The path to the engines directory.  Ignored in set-user-ID and set-group-ID programs.

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.

       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)

       Copyright 2000-2018 The OpenSSL Project Authors. All Rights Reserved.

       Licensed under the OpenSSL license (the "License").  You may not use this file except in compliance with
       the License.  You can obtain a copy in the file LICENSE in the source distribution or at
       <https://www.openssl.org/source/license.html>.