wallet release 0.12 (secure data management system) Written by Russ Allbery Copyright 2006, 2007, 2008, 2009, 2010 Board of Trustees, Leland Stanford Jr. University. This software is distributed under a BSD-style license. Please see the file LICENSE in the distribution 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. Currently, the only ACL type supported matches a single Kerberos principal name, but this will be extended in future releases. Currently, the object types supported are simple files and Kerberos keytabs. 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 5.6.0 or later. It uses the Perl DBI layer to talk to a database, and therefore the DBI module and a DBD module for the database it will use must be installed. Currently, the server has only been tested against SQLite 3 and MySQL 5 and 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. The Heimdal support requires the Heimdal::Kadm5 Perl module. The MIT Kerberos support requires the MIT Kerberos kadmin client program be installed. In either case, 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. 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 test suite, you must have Perl 5.8 or later and the Perl DBI module installed. You will also need a DBD module installed for the database backend you want to use (currently, either DBD::SQLite or DBD::mysql). The other modules are available from CPAN and may be available as part of your OS (many Linux distributions have them as packages, for example). To run the full test suite, additionally all of the above software requirements must be met. Tests requiring some bit of software that's not installed should be skipped, but not all the permutations have been checked. The full test suite also requires the Test::Pod Perl module (available from CPAN), that remctld be installed and available on the user's path or in /usr/local/sbin or /usr/sbin, 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. 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 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. To change the Perl module installation location, you will need to run perl on Makefile.PL in the perl subdirectory of the build tree with appropriate options and rebuild the module after running make and before running make install. 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 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 docuemntation (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). 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, and the initial wallet-rekey implementation.