wallet release 1.3

(secure data management system)

Written by Russ Allbery <eagle@eyrie.org>

Copyright 2014, 2016 Russ Allbery <eagle@eyrie.org>. Copyright 2006, 2007, 2008, 2009, 2010, 2012, 2013, 2014 The Board of Trustees of the Leland Stanford Junior University. This software is distributed under a BSD-style license. Please see the section LICENSE below for more information.

BLURB

The wallet is a system for managing secure data, authorization rules to retrieve or change that data, and audit rules for documenting actions taken on that data. Objects of various types may be stored in the wallet or generated on request and retrieved by authorized users. The wallet tracks ACLs, metadata, and trace information. It is built on top of the remctl protocol and uses Kerberos GSS-API authentication. One of the object types it supports is Kerberos keytabs, making it suitable as a user-accessible front-end to Kerberos kadmind with richer ACL and metadata operations.

DESCRIPTION

The wallet is a client/server system using a central server with a supporting database and a stand-alone client that can be widely distributed to users. The server runs on a secure host with access to a local database; tracks object metadata such as ACLs, attributes, history, expiration, and ownership; and has the necessary access privileges to create wallet-managed objects in external systems (such as Kerberos service principals). The client uses the remctl protocol to send commands to the server, store and retrieve objects, and query object metadata. The same client can be used for both regular user operations and wallet administrative actions.

All wallet actions are controlled by a fine-grained set of ACLs. Each object has an owner ACL and optional get, store, show, destroy, and flags ACLs that control more specific actions. A global administrative ACL controls access to administrative actions. An ACL consists of zero or more entries, each of which is a generic scheme and identifier pair, allowing the ACL system to be extended to use any existing authorization infrastructure. Supported ACL types include Kerberos principal names, regexes matching Kerberos principal names, and LDAP attribute checks.

Currently, the object types supported are simple files, Kerberos keytabs, WebAuth keyrings, and Duo integrations. By default, whenever a Kerberos keytab object is retrieved from the wallet, the key is changed in the Kerberos KDC and the wallet returns a keytab for the new key. However, a keytab object can also be configured to preserve the existing keys when retrieved. Included in the wallet distribution is a script that can be run via remctl on an MIT Kerberos KDC to extract the existing key for a principal, and the wallet system will use that interface to retrieve the current key if the unchanging flag is set on a Kerberos keytab object for MIT Kerberos. (Heimdal doesn't require any special support.)

REQUIREMENTS

The wallet client is written in C and builds against the C remctl libraries. You will have to install the remctl client libraries in order to build it. remctl can be obtained from:

    http://www.eyrie.org/~eagle/software/remctl/

The wallet client will build with either MIT Kerberos or Heimdal.

The wallet server is written in Perl and requires Perl 5.8.0 or later plus Module::Build to build. It uses DBIx::Class and DBI to talk to a database, and therefore the DBIx::Class and DBI modules (and their dependencies) and a DBD module for the database it will use must be installed. The Date::Parse (part of the TimeDate distribution) and DateTime modules are required for date handling, and the SQL::Translator Perl module is also required for schema deployment and database upgrades. You will also need the DateTime::Format::* module corresponding to your DBD module (such as DateTime::Format::SQLite or DateTime::Format::PG).

Currently, the server has only been tested against SQLite 3, MySQL 5, and PostgreSQL, and prebuilt SQL files (for database upgrades) are only provided for those servers. It will probably not work fully with other database backends. Porting is welcome.

The wallet server is intended to be run under remctld and use remctld to do authentication. It can be ported to any other front-end, but doing so will require writing a new version of server/wallet-backend that translates the actions in that protocol into calls to the Wallet::Server Perl object.

The file object support in the wallet server requires the Digest::MD5 Perl module, which comes with recent versions of Perl and is available on CPAN for older versions.

The keytab support in the wallet server supports either Heimdal or MIT Kerberos KDCs and has experimental support for Active Directory. The Heimdal support requires the Heimdal::Kadm5 Perl module. The MIT Kerberos support requires the MIT Kerberos kadmin client program be installed. The Active Directory support requires the Net::LDAP, Authen::SASL, and IPC::Run Perl modules and the msktutil client program. In all cases, wallet also requires that the wallet server have a keytab for a principal with appropriate access to create, modify, and delete principals from the KDC (as configured in kadm5.acl on an MIT Kerberos KDC).

To support the unchanging flag on keytab objects with an MIT Kerberos KDC, the Net::Remctl Perl module (shipped with remctl) must be installed on the server and the keytab-backend script must be runnable via remctl on the KDC. This script also requires an MIT Kerberos kadmin.local binary that supports the -norandkey option to ktadd. This option is included in MIT Kerberos 1.7 and later.

The WebAuth keyring object support in the wallet server requires the WebAuth Perl module from WebAuth 4.4.0 or later.

The Duo integration object support in the wallet server requires the Net::Duo, JSON, and Perl6::Slurp Perl modules.

The password object support in the wallet server requires the Crypt::GeneratePassword Perl module.

To support the LDAP attribute ACL verifier, the Authen::SASL and Net::LDAP Perl modules must be installed on the server. This verifier only works with LDAP servers that support GSS-API binds.

To support the NetDB ACL verifier (only of interest at sites using NetDB to manage DNS), the Net::Remctl Perl module must be installed on the server.

To run the full test suite, all of the above software requirements must be met. The full test suite also requires that remctld be installed and available on the user's path or in /usr/local/sbin or /usr/sbin, that sqlite3 be installed and available on the user's path, that test cases can run services on and connect to port 14373 on 127.0.0.1, and that kinit and either kvno or kgetcred (which come with Kerberos) be installed and available on the user's path. The full test suite also requires a local keytab and some additional configuration.

The following additional Perl modules will be used if present:

    Test::MinimumVersion
    Test::Pod
    Test::Spelling
    Test::Strict

All are available on CPAN. Those tests will be skipped if the modules are not available.

To enable tests that don't detect functionality problems but are used to sanity-check the release, set the environment variable RELEASE_TESTING to a true value. To enable tests that may be sensitive to the local environment or that produce a lot of false positives without uncovering many problems, set the environment variable AUTHOR_TESTING to a true value.

To bootstrap from a Git checkout, or if you change the Automake files and need to regenerate Makefile.in, you will need Automake 1.11 or later. For bootstrap or if you change configure.ac or any of the m4 files it includes and need to regenerate configure or config.h.in, you will need Autoconf 2.64 or later.

BUILD AND INSTALLATION

You can build and install wallet with the standard commands:

    ./configure
    make
    make install

If you are upgrading the wallet server from an earlier installed version, run wallet-admin upgrade after installation to upgrade the database schema. See the wallet-admin manual page for more information.

Pass --enable-silent-rules to configure for a quieter build (similar to the Linux kernel). Use make warnings instead of make to build with full GCC compiler warnings (requires a relatively current version of GCC).

The last step will probably have to be done as root. Currently, this always installs both the client and the server.

You can pass the --with-wallet-server and --with-wallet-port options to configure to compile in a default wallet server and port. If no port is set, the remctl default port is used. If no server is set, the server must be specified either in krb5.conf configuration or on the wallet command line or the client will exit with an error.

By default, wallet uses whatever Perl executable exists in the current PATH. That Perl's path is what the server scripts will use, and that Perl's configuration will be used to determine where the server Perl modules will be installed.

To specify a particular Perl executable to use, either set the PERL environment variable or pass it to configure like:

    ./configure PERL=/path/to/my/perl

By default, wallet installs itself under /usr/local except for the server Perl modules, which are installed into whatever default site module path is used by your Perl installation. To change the installation location of the files other than the Perl modules, pass the --prefix=DIR argument to configure.

If remctl was installed in a path not normally searched by your compiler, you must specify its installation prefix to configure with the --with-remctl=DIR option, or alternately set the path to the include files and libraries separately with --with-remctl-include=DIR and --with-remctl-lib=DIR.

Normally, configure will use krb5-config to determine the flags to use to compile with your Kerberos libraries. If krb5-config isn't found, it will look for the standard Kerberos libraries in locations already searched by your compiler. If the the krb5-config script first in your path is not the one corresponding to the Kerberos libraries you want to use or if your Kerberos libraries and includes aren't in a location searched by default by your compiler, you need to specify --with-krb5=PATH and --with-gssapi=PATH:

    ./configure --with-krb5=/usr/pubsw --with-gssapi=/usr/pubsw

You can also individually set the paths to the include directory and the library directory with --with-krb5-include, --with-krb5-lib, --with-gssapi-include, and --with-gssapi-lib. You may need to do this if Autoconf can't figure out whether to use lib, lib32, or lib64 on your platform. Note that these settings aren't used if a krb5-config script is found.

To specify a particular krb5-config script to use, either set the KRB5_CONFIG environment variable or pass it to configure like:

    ./configure KRB5_CONFIG=/path/to/krb5-config

To not use krb5-config and force library probing even if there is a krb5-config script on your path, set KRB5_CONFIG to a nonexistent path:

    ./configure KRB5_CONFIG=/nonexistent

You can build wallet in a different directory from the source if you wish. To do this, create a new empty directory, cd to that directory, and then give the path to configure when running configure. Everything else should work as above.

You can pass the --enable-reduced-depends flag to configure to try to minimize the shared library dependencies encoded in the binaries. This omits from the link line all the libraries included solely because the Kerberos libraries depend on them and instead links the programs only against libraries whose APIs are called directly. This will only work with shared Kerberos libraries and will only work on platforms where shared libraries properly encode their own dependencies (such as Linux). It is intended primarily for building packages for Linux distributions to avoid encoding unnecessary shared library dependencies that make shared library migrations more difficult. If none of the above made any sense to you, don't bother with this flag.

TESTING

The wallet system comes with an extensive test suite which you can run with:

    make check

In order to test the client in a meaningful way and test the keytab support in the server, however, you will need to do some preparatory work before running the test suite. Review the files:

    tests/config/README
    perl/t/data/README

and follow the instructions in those files to enable the full test suite.

The test suite also requires some additional software be installed that isn't otherwise used by the wallet. See REQUIREMENTS above for the full list of requirements for the test suite. The test driver attempts to selectively skip those tests for which the necessary configuration is not available, but this has not yet been fully tested in all of its possible permutations.

If a test fails, you can run a single test with verbose output via:

    tests/runtests -o <name-of-test>

Do this instead of running the test program directly since it will ensure that necessary environment variables are set up.

CONFIGURATION

For the basic setup and configuration of the wallet server, see the file docs/setup in the source distribution. You will need to set up a database on the server (unless you're using SQLite), initialize the database, install remctld and the wallet Perl modules, and set up remctld to run the wallet-backend program.

Before setting up the wallet server, review the Wallet::Config documentation (with man Wallet::Config or perldoc Wallet::Config). There are many customization options, some of which must be set. You may also need to create a Kerberos keytab for the keytab object backend and give it appropriate ACLs, and set up keytab-backend and its remctld configuration on your KDC if you want unchanging flag support.

The wallet client supports reading configuration settings from the system krb5.conf file. For more information, see the CONFIGURATION section of the wallet client man page (man wallet).

SUPPORT

The wallet web page at:

    http://www.eyrie.org/~eagle/software/wallet/

will always have the current version of this package, the current documentation, and pointers to any additional resources.

New releases of the wallet are announced on the kerberos@mit.edu mailing list and discussion of the wallet (particularly the keytab components) are welcome there.

I welcome bug reports and patches for this package at eagle@eyrie.org. However, please be aware that I tend to be extremely busy and work projects often take priority. I'll save your mail and get to it as soon as I can, but it may take me a couple of months.

SOURCE REPOSITORY

The wallet is maintained using Git. You can access the current source by cloning the repository at:

    git://git.eyrie.org/kerberos/wallet.git

or view the repository on the web at:

    http://git.eyrie.org/?p=kerberos/wallet.git

When contributing modifications, patches (possibly generated by git-format-patch) are preferred to Git pull requests.

THANKS

To Roland Schemers for the original idea that kicked off this project and for the original implementation of the leland_srvtab system, which was its primary inspiration.

To Anton Ushakov for his prior work on Kerberos v5 synchronization and his enhancements to kasetkey to read a key from an existing srvtab.

To Jeffrey Hutzelman for his review of the original wallet design and multiple useful discussions about what actions and configurations the wallet would need to support to be useful outside of Stanford.

To Huaqing Zheng, Paul Pavelko, David Hoffman, and Paul Keser for their reviews of the wallet system design and comments on design decisions and security models.

To Jon Robertson for the refactoring of Wallet::Kadmin, Heimdal support, many of the wallet server-side reports, the initial wallet-rekey implementation, and lots of work on object and ACL types including nested ACLs.

To Bill MacAllister for Wallet::Kadmin::AD and the implementation of keytab object types backed by Active Directory.

LICENSE

The wallet distribution as a whole is covered by the following copyright statement and license:

  Copyright 2014, 2016 Russ Allbery <eagle@eyrie.org>
  Copyright 2006, 2007, 2008, 2009, 2010, 2012, 2013, 2014
      The Board of Trustees of the Leland Stanford Junior University
  Permission is hereby granted, free of charge, to any person obtaining
  a copy of this software and associated documentation files (the
  "Software"), to deal in the Software without restriction, including
  without limitation the rights to use, copy, modify, merge, publish,
  distribute, sublicense, and/or sell copies of the Software, and to
  permit persons to whom the Software is furnished to do so, subject to
  the following conditions:
  The above copyright notice and this permission notice shall be
  included in all copies or substantial portions of the Software.
  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
  IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
  CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
  TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
  SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

All individual files without an explicit exception below are released under this license. Some files may have additional copyright holders as noted in those files. There is detailed information about the licensing of each file in the LICENSE file in this distribution.

Some files in this distribution are individually released under different licenses, all of which are compatible with the above general package license but which may require preservation of additional notices. All required notices are preserved in the LICENSE file.

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