= ABAC =

[[TOC]]

The ABAC project has designed and implemented tools for using Attribute-Based Access Control, a scalable authorization system based on formal logic.  It maps principals to attributes and uses the attribute to make an authorization decision, e.g., if user1 has the login attribute the login program will alllow them to log in.  This library, libabac, is a base on which to build those tools.  It is in use in the [http://fedd.deterlab.net DETER federation system] and being integrated with the [http://geni.net GENI network testbed].

If you are new to ABAC, you may find the [http://groups.geni.net/geni/wiki/TIEDABACModel introductory material] from our [http://groups.geni.net/geni/wiki/TIED TIED project] helpful.  That material summarizes the power and semantics of ABAC and links to [http://groups.geni.net/geni/wiki/TIEDABACDemo examples of ABAC policy] illustrated using an early example of [CrudgeDocs the Crudge ABAC policy browser].

The latest ABAC RT0 version is '''ABAC 0.1.4'''. Jump down to [#Source Source] to download it.

== What's Included ==

The core libabac distribution includes:

 * libabac, a linkable C/C++ library 
 * Perl and Python bindings to libabac
 * A standalone java implementation 
 * creddy, a command line credential management tool

These ABAC tools use libabac 

 * [CrudgeDocs crudge] a visual editor for ABAC policies and proofs
   * [http://abac.deterlab.net/java/crudge.jnlp webstart link]
 * [CredPrinterDocs credential printer] an XMLRPC service to convert credentials to a text representation

== Getting started: Installing libabac ==

Installing libabac is a straightforward {{{configure}}}, {{{make}}}, {{{make install}}} sequence.  There are a few things to be careful of depending on your operating system.

=== Software Dependencies ===

Libabac depends on openssl and the [http://www.aleksey.com/xmlsec/ xmlsec1 digital signature library].  Most unix-like operating systems have openssl installed and have xmlsec1 as a standard package. The perl and python bingings are generated by [http://www.swig.org/ swig] 1.3, and the build system uses automake and some autoconf macros.

To set up Ubuntu for building libabac:

{{{
$ sudo apt-get -y install autoconf-archive automake g++ git-core libtool python-dev swig libxmlsec1-dev
}}}

Under FreeBSD, use the ports system to install the following packages:

{{{
devel/libtool
devel/automake
devel/autoconf-archive
devel/swig13
devel/pkg-config
security/xmlsec1
lang/perl
lang/python
}}}

If you plan to build the java implementation on ubuntu you should also 

{{{
$ apt-get -y install openjdk-7-jdk ant ant-optional
}}}

Similarly in FreeBSD install 

{{{
devel/apache-ant
java/openjdk6
}}}

We have seen no differences under the various JDKs.

=== Installation ===

Then get the [http://abac.deterlab.net/src/abac-0.1.4.tgz source], untar it, change to the {{{abac-0.1.4}}} directory and do the standars install sequence:

{{{
# Ubuntu users: ./configure --prefix=/usr
$ ./configure
$ make
$ sudo make install
}}}

To confirm that your install succeeded:

{{{
$ cd examples
$ make
}}}

Libabac uses the standard GNU install prefix of {{{/usr/local}}}.  '''If you are on Ububtu or another distribution that does not search /usr/local/lib for shared libraries, make sure you use ./configure --prefix=/usr'''

=== Tracking Development ===

If you would like to track the libabac development, you can pull code from out publically available git repository:

{{{
$ git clone git://abac.deterlab.net/abac.git
}}}

Current sources can be [/browser browsed on the web].

=== Releases  ===

See the [source:/doc/ChangeLog@mei_rt0 ChangeLog] for details about each release
 * 2013-05-XX: ABAC 0.1.4 released
 * 2011-04-11: Crudge 1.0 released
 * 2011-03-30: ABAC 0.1.3 released
 * 2010-10-01: ABAC 0.1.2 released
 * ~~2010-09-17~~ 2010-09-20: ABAC 0.1.1 released
  * '''Update:''' We fixed a one-line bug in creddy. If you downloaded this over the weekend, please fetch it again.

== Using libabac ==

Libabac allows developers to import signed ABAC statements about principals and attributes and prove that certain principals have those attributes ([http://groups.geni.net/geni/wiki/TIEDABACModel more detail about ABAC logic]).  The basic structures that libabac uses to support those operations are identities, attributes, and a context for those.


=== Identities ===

An identity in ABAC is a principal who has issued or can issue attributes (valid ABAC statements).  libabac allows one to create new principals and to import identities from X.509 identity certificates.  To create a principal from scratch (in python):

{{{
import ABAC

id = ABAC.ID("newGuy", 5*365*3600*24)
}}}

The first parameter is a common name to use for the identity and the second parameter is the validity.  Associated with this identity is a public/private key pair that can be used to sign new ABAC attributes.  In ABAC statements the principal is referred to an identifier derived from its public key.  You can access that identitfer using the keyid() method:


{{{
import ABAC

id = ABAC.ID("newGuy", 5*365*3600*24)
print id.keyid()
}}}
prints something like:

{{{
481365b6eced33c0b06674d506b92f01f69e05fd
}}}

The other way to initialize an idenitiy is to read the contents from an X.509 certificate file, or from the contents of such a file (referred to as a chunk):

{{{
import ABAC

id1 = ABAC.ID("./newGuy.pem")

try:
    f = open("./newGuy.pem")
    id2 = ABAC.ID_chunk(f.read())
    f.close()
except:
    pass

print "%s %s" % (id1.keyid(), id2.keyid())
}}}

The {{{write_cert}}} and {{{write_cert_name}}} methods write the X.509 certificate from an identity.  The private keys can similarly be read or written using {{{read_privkey_name}}} and {{{read_privkey}}}.  The following snippet creates an identity, writes it to 2 files and reads it from those files printing the results.  The output files will not contain the private key.

{{{

import ABAC

id = ABAC.ID("newGuy", 5*365*3600*24)

id.write_cert_name("./newGuy.pem")

id1 = ABAC.ID("./newGuy.pem")

try:
    f = open("./newGuy.pem")
    id2 = ABAC.ID_chunk(f.read())
    f.close()
except:
    pass

print "%s %s %s" % (id.keyid(), id1.keyid(), id2.keyid())


}}}

== Contacts ==

 * [http://lists.deterlab.net/listinfo/abac-dev devevelopers mailing list]
 * Ted Faber faber@ISI.EDU
 * Mei-Hui Su mei@ISI.EDU
 * Steve Schwab schwab@ISI.EDU