Added a new password object type

The password type inherits almost everything from the file object, but
if you try to get a password object that has never been stored, we
generate a random string to put in the object rather than just
erroring out.  The maximum and minimum length of the string can be set
in the wallet config.

If a password object was stored earlier and then cleared out, we don't
generate another random string.

Change-Id: I17a65ca7dac9d4430e8a731f417297890ee612bb

3 files changed, 254 insertions, 0 deletions

diff --git a/perl/lib/Wallet/Admin.pm b/perl/lib/Wallet/Admin.pm
index 8120e9c..a8b8368 100644
--- a/perl/lib/Wallet/Admin.pm
+++ b/perl/lib/Wallet/Admin.pm
@@ -131,6 +131,7 @@ sub default_data {
                [ 'duo-radius', 'Wallet::Object::Duo::RadiusProxy' ],
                [ 'duo-rdp',    'Wallet::Object::Duo::RDP' ],
                [ 'file',       'Wallet::Object::File' ],
+               [ 'password',   'Wallet::Object::Password' ],
                [ 'keytab',     'Wallet::Object::Keytab' ],
                [ 'wa-keyring', 'Wallet::Object::WAKeyring' ]);
     ($r1) = $self->{schema}->resultset('Type')->populate (\@record);
diff --git a/perl/lib/Wallet/Config.pm b/perl/lib/Wallet/Config.pm
index 2eb57f9..76c7ecd 100644
--- a/perl/lib/Wallet/Config.pm
+++ b/perl/lib/Wallet/Config.pm
@@ -260,6 +260,49 @@ our $FILE_MAX_SIZE;
 
 =back
 
+=head1 PASSWORD OBJECT CONFIGURATION
+
+These configuration variables only need to be set if you intend to use the
+C<password> object type (the Wallet::Object::Password class).  You will also
+need to set the FILE_MAX_SIZE value from the file object configuration, as
+that is inherited.
+
+=over 4
+
+=item PWD_FILE_BUCKET
+
+The directory into which to store password objects.  Password objects will
+be stored in subdirectories of this directory.  See
+L<Wallet::Object::Password> for the full details of the naming scheme.  This
+directory must be writable by the wallet server and the wallet server must
+be able to create subdirectories of it.
+
+PWD_FILE_BUCKET must be set to use file objects.
+
+=cut
+
+our $PWD_FILE_BUCKET;
+
+=item PWD_LENGTH_MIN
+
+The minimum length for any auto-generated password objects created when get
+is run before data is stored.
+
+=cut
+
+our $PWD_LENGTH_MIN = 20;
+
+=item PWD_LENGTH_MAX
+
+The maximum length for any auto-generated password objects created when get
+is run before data is stored.
+
+=cut
+
+our $PWD_LENGTH_MAX = 21;
+
+=back
+
 =head1 KEYTAB OBJECT CONFIGURATION
 
 These configuration variables only need to be set if you intend to use the
diff --git a/perl/lib/Wallet/Object/Password.pm b/perl/lib/Wallet/Object/Password.pm
new file mode 100644
index 0000000..d06c8a6
--- /dev/null
+++ b/perl/lib/Wallet/Object/Password.pm
@@ -0,0 +1,210 @@
+# Wallet::Object::Password -- Password object implementation for the wallet.
+#
+# Written by Jon Robertson <jonrober@stanford.edu>
+# Copyright 2015
+#     The Board of Trustees of the Leland Stanford Junior University
+#
+# See LICENSE for licensing terms.
+
+##############################################################################
+# Modules and declarations
+##############################################################################
+
+package Wallet::Object::Password;
+require 5.006;
+
+use strict;
+use warnings;
+use vars qw(@ISA $VERSION);
+
+use Crypt::GeneratePassword qw(chars);
+use Digest::MD5 qw(md5_hex);
+use Wallet::Config ();
+use Wallet::Object::File;
+
+@ISA = qw(Wallet::Object::File);
+
+# This version should be increased on any code change to this module.  Always
+# use two digits for the minor version with a leading zero if necessary so
+# that it will sort properly.
+$VERSION = '0.01';
+
+##############################################################################
+# File naming
+##############################################################################
+
+# Returns the path into which that password object will be stored or undef on
+# error.  On error, sets the internal error.
+sub file_path {
+    my ($self) = @_;
+    my $name = $self->{name};
+    unless ($Wallet::Config::PWD_FILE_BUCKET) {
+        $self->error ('password support not configured');
+        return;
+    }
+    unless ($name) {
+        $self->error ('password objects may not have empty names');
+        return;
+    }
+    my $hash = substr (md5_hex ($name), 0, 2);
+    $name =~ s/([^\w-])/sprintf ('%%%02X', ord ($1))/ge;
+    my $parent = "$Wallet::Config::PWD_FILE_BUCKET/$hash";
+    unless (-d $parent || mkdir ($parent, 0700)) {
+        $self->error ("cannot create password bucket $hash: $!");
+        return;
+    }
+    return "$Wallet::Config::PWD_FILE_BUCKET/$hash/$name";
+}
+
+##############################################################################
+# Core methods
+##############################################################################
+
+# Return the contents of the file.
+sub get {
+    my ($self, $user, $host, $time) = @_;
+    $time ||= time;
+    my $id = $self->{type} . ':' . $self->{name};
+    if ($self->flag_check ('locked')) {
+        $self->error ("cannot get $id: object is locked");
+        return;
+    }
+    my $path = $self->file_path;
+    return unless $path;
+
+    # If nothing is yet stored, generate a random password and save it to
+    # the file.
+    my $schema = $self->{schema};
+    my %search = (ob_type => $self->{type},
+                  ob_name => $self->{name});
+    my $object = $schema->resultset('Object')->find (\%search);
+    unless ($object->ob_stored_on) {
+        unless (open (FILE, '>', $path)) {
+            $self->error ("cannot store initial settings for $id: $!\n");
+            return;
+        }
+        my $pass = chars ($Wallet::Config::PWD_LENGTH_MIN,
+                          $Wallet::Config::PWD_LENGTH_MAX);
+        print FILE $pass;
+        $self->log_action ('store', $user, $host, $time);
+        unless (close FILE) {
+            $self->error ("cannot get $id: $!");
+            return;
+        }
+    }
+
+    unless (open (FILE, '<', $path)) {
+        $self->error ("cannot get $id: object has not been stored");
+        return;
+    }
+    local $/;
+    my $data = <FILE>;
+    unless (close FILE) {
+        $self->error ("cannot get $id: $!");
+        return;
+    }
+    $self->log_action ('get', $user, $host, $time);
+    return $data;
+}
+
+1;
+__END__
+
+##############################################################################
+# Documentation
+##############################################################################
+
+=head1 NAME
+
+Wallet::Object::Password - Password object implementation for wallet
+
+=for stopwords
+API HOSTNAME DATETIME keytab remctld backend nul Allbery wallet-backend
+
+=head1 SYNOPSIS
+
+    my @name = qw(file mysql-lsdb)
+    my @trace = ($user, $host, time);
+    my $object = Wallet::Object::Password->create (@name, $schema, @trace);
+    unless ($object->store ("the-password\n")) {
+        die $object->error, "\n";
+    }
+    my $password = $object->get (@trace);
+    $object->destroy (@trace);
+
+=head1 DESCRIPTION
+
+Wallet::Object::Password is an extension of Wallet::Object::File,
+acting as a representation of simple file objects in the wallet.  The
+difference between the two is that if there is no data stored in a
+password object when a user tries to get it for the first time, then a
+random string suited for a password will be generated and put into the
+object data.
+
+It implements the wallet object API and provides the necessary
+glue to store a file on the wallet server, retrieve it later, and delete
+it when the password object is deleted.
+
+To use this object, the configuration option specifying where on the
+wallet server to store password objects must be set.  See
+L<Wallet::Config> for details on this configuration parameter and
+information about how to set wallet configuration.
+
+=head1 METHODS
+
+This object mostly inherits from Wallet::Object::File.  See the
+documentation for that class for all generic methods.  Below are only
+those methods that are overridden or behave specially for this
+implementation.
+
+=over 4
+
+=item get(PRINCIPAL, HOSTNAME [, DATETIME])
+
+Retrieves the current contents of the file object or undef on error.
+store() must be called before get() will be successful.  The caller should
+call error() to get the error message if get() returns undef.  PRINCIPAL,
+HOSTNAME, and DATETIME are stored as history information.  PRINCIPAL
+should be the user who is downloading the keytab.  If DATETIME isn't
+given, the current time is used.
+
+=back
+
+=head1 FILES
+
+=over 4
+
+=item PWD_FILE_BUCKET/<hash>/<file>
+
+Password files are stored on the wallet server under the directory
+PWD_FILE_BUCKET as set in the wallet configuration.  <hash> is the
+first two characters of the hex-encoded MD5 hash of the wallet password
+object name, used to not put too many files in the same directory.
+<file> is the name of the password object with all characters other
+than alphanumerics, underscores, and dashes replaced by C<%> and the
+hex code of the character.
+
+=back
+
+=head1 LIMITATIONS
+
+The wallet implementation itself can handle arbitrary password object
+names. However, due to limitations in the B<remctld> server usually
+used to run B<wallet-backend>, password object names containing nul
+characters (ASCII 0) may not be permitted.  The file system used for
+storing file objects may impose a length limitation on the
+password object name.
+
+=head1 SEE ALSO
+
+remctld(8), Wallet::Config(3), Wallet::Object::File(3),
+wallet-backend(8)
+
+This module is part of the wallet system.  The current version is
+available from L<http://www.eyrie.org/~eagle/software/wallet/>.
+
+=head1 AUTHOR
+
+Jon Robertson <jonrober@stanford.edu>
+
+=cut