DESCRIPTION
This module provides a Perl function to perform password
verification using Kerberos 5. It is intended for use by
applications that cannot use the Kerberos protocol directly.
If it must be run on a system that receives a username and
password over the network, steps should be taken to ensure
that these are passed to the server in a cryptographically
secure manner.
kpass() attempts to obtain credentials for the given
username and password from the Kerberos AS, then obtain
credentials for a local service from the Kerberos TGS to
verify the authenticity of the AS response. Empty strings
can be passed as the 3rd and/or 4th arguments to use the
default service name ("host") and the fully canonicalized
primary hostname of the system that the function is executed
on. The fifth argument may be omitted to use the system's
default keytab file.
kpass() returns -1 if an error occurs, 0 if the username or
password is incorrect, or 1 if password verification is
successful. Errors and authentication failures are recorded
via syslog(3). Because of deficiencies in Perl's syslog
implementation in Sys::Syslog(3), there's no clean way to
log output to any facility other than the default LOG_USER.
One possible way around this problem is to use the
Unix::Syslog module available on CPAN, which correctly uses
your platform's native syslog library routines to perform
the functions.
Prerequisites:
- perl 5
- MIT Kerberos V5 Release 1.2.x or better (this module
also appears to work with Heimdal Kerberos, although
I have not extensively tested it)
- Creation of an application service principal on the Kerberos
server in order to verify the KDC's response. And access to
a local keytab file containing the key for that principal.
To build and install:
1. Edit "Makefile.PL" to reflect the proper locations of the MIT
Kerberos 5 libraries and include directories for your system.
2. perl Makefile.PL
3. make
4. make test
5. (as root) make install
6. make distclean
Note that it may be necessary to create a keytab file specifically
for use with this module since the default system keytab file is
usually readable only by root.
Shumon Huque
E-mail: <shuque -at- isc.upenn.edu>
University of Pennsylvania.
Copyright (c) 2004, 2005 Shumon Huque. All rights reserved. This
program is free software; you can redistribute it and/or modify it
under the same terms as Perl itself.
