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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 ooppeennssssll..ccnnff and in a

few other places like SSPPKKAACC files and certificate extension files for the xx550099 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 [[ sseeccttiioonnnnaammee ]] 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 ddeeffaauulltt section this is usually unnamed and is 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 EENNVV.

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 nnaammee==vvaalluuee The nnaammee string can contain any alphanumeric characters as well as a few punctuation symbols such as .. ,, ;; and . The vvaalluuee 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 $$vvaarr or $${{vvaarr}}: 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 $$sseeccttiioonn::::nnaammee

or $${{sseeccttiioonn::::nnaammee}}. By using the form $$EENNVV::::nnaammee environment variables

can be substituted. It is also possible to assign values to environment variables by using the name EENNVV::::nnaammee, this will work if the program looks up environment variables using the CCOONNFF library instead of calling ggeetteennvv(()) directly. 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 vvaalluuee string can be spread across multiple lines. In addition the sequences \\nn, \\rr, \\bb and \\tt are recognized. OOPPEENNSSSSLL LLIIBBRRAARRYY CCOONNFFIIGGUURRAATTIIOONN

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 ooppeennssssll 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 ooppeennssssllccoonnff which is used by the ooppeennssssll utility. Other applications may use an alternative name such as mmyyaapppplliiccaattoonnccoonnff.

The configuration section should consist of a set of name value pairs

which contain specific module configuration information. The nnaammee

represents the name of the configuration module the meaning of the

vvaalluuee is module specific: it may, for example, represent a further

configuration section containing configuration module specific

information. E.g. opensslconf = opensslinit [opensslinit] oidsection = newoids engines = enginesection [newoids] ... new oids here ... [enginesection] ... engine stuff here ...

Currently there are two configuration modules. One for ASN1 objects

another for ENGINE configuration.

AASSNN11 OOBBJJEECCTT CCOONNFFIIGGUURRAATTIIOONN MMOODDUULLEE This module has the name ooiiddsseeccttiioonn. 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 ooppeennssssll utility sub commands already have their own ASN1 OBJECT section functionality not all do. By using the ASN1

OBJECT configuration module aallll the ooppeennssssll utility sub commands can

see the new objects as well as any compliant applications. For example: [newoids] somenewoid = 1.2.3.4 someotheroid = 1.2.3.5 EENNGGIINNEE CCOONNFFIIGGUURRAATTIIOONN MMOODDUULLEE

This ENGINE configuration module has the name eennggiinneess. The value of

this variable points to a section containing further ENGINE

configuration information.

The section pointed to by eennggiinneess is a table of engine names (though

see eennggiinneeiidd below) and further sections containing configuration

informations 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: [enginesection]

# Configure ENGINE named "foo"

foo = foosection

# Configure ENGINE named "bar"

bar = barsection [foosection] ... foo ENGINE specific commands ... [barsection] ... "bar" ENGINE specific commands ... The command eennggiinneeiidd is used to give the ENGINE name. If used this command must be first. For example: [enginesection]

# This would normally handle an ENGINE named "foo"

foo = foosection [foosection]

# Override default name and use "myfoo" instead.

engineid = myfoo The command ddyynnaammiiccppaatthh loads and adds an ENGINE from the given path. It is equivalent to sending the ctrls SSOOPPAATTHH with the path argument followed by LLIISSTTAADDDD with value 2 and LLOOAADD 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 iinniitt determines whether to initialize the ENGINE. If the value is 00 the ENGINE will not be initialized, if 11 and attempt it made to initialized the ENGINE immediately. If the iinniitt 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 ddeeffaauullttaallggoorriitthhmmss sets the default algorithms an ENGINE will supply using the functions EENNGGIINNEEsseettddeeffaauullttssttrriinngg(()) 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 EEMMPPTTYY then no value is sent to the command. For example: [enginesection]

# Configure ENGINE named "foo"

foo = foosection [foosection]

# Load engine from DSO

dynamicpath = /some/path/fooengine.so

# A foo specific ctrl.

somectrl = somevalue

# Another ctrl that doesn't take a value.

otherctrl = EMPTY

# Supply all default algorithms

defaultalgorithms = ALL NNOOTTEESS

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 HHOOMMEE which may not

be defined on non Unix systems and would cause an error. This can be worked around by including a ddeeffaauulltt 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 EEXXAAMMPPLLEESS 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" EEXXAAMMPPLLEESS

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

[ sectionone ]

# 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 [ sectiontwo ]

greeting = $sectionone::message

This next example shows how to expand environment variables safely. Suppose you want a variable called ttmmppffiillee to refer to a temporary filename. The directory it is placed in can determined by the the TTEEMMPP or TTMMPP 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 TTEEMMPP taking priority and //ttmmpp 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

BUGS

Currently there is no way to include characters using the octal \\nnnnnn 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 \\nn 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.