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-rw-r--r--perl/Wallet/Kadmin/Heimdal.pm74
-rw-r--r--perl/Wallet/Kadmin/MIT.pm68
2 files changed, 125 insertions, 17 deletions
diff --git a/perl/Wallet/Kadmin/Heimdal.pm b/perl/Wallet/Kadmin/Heimdal.pm
index 0ac8cd9..e066006 100644
--- a/perl/Wallet/Kadmin/Heimdal.pm
+++ b/perl/Wallet/Kadmin/Heimdal.pm
@@ -39,6 +39,23 @@ sub canonicalize_principal {
return $principal;
}
+# Read the entirety of a possibly binary file and return the contents. If
+# reading the file fails, set the error message and return undef.
+sub slurp_file {
+ my ($self, $file) = @_;
+ unless (open (TMPFILE, '<', $file)) {
+ $self->error ("cannot open temporary file $file: $!");
+ return;
+ }
+ local $/;
+ my $data = <TMPFILE>;
+ unless (close TMPFILE) {
+ $self->error ("cannot read temporary file $file: $!");
+ return;
+ }
+ return $data;
+}
+
##############################################################################
# Public interfaces
##############################################################################
@@ -93,11 +110,38 @@ sub create {
return 1;
}
-# Create a keytab from a principal. Takes the principal, the file, and
-# optionally a list of encryption types to which to limit the keytab. Return
-# true if successful, false otherwise. If the keytab creation fails, sets the
-# error.
+# Create a keytab for a principal. Returns the keytab as binary data or undef
+# on failure, setting the error.
sub keytab {
+ my ($self, $principal) = @_;
+ $principal = $self->canonicalize_principal ($principal);
+ my $kadmin = $self->{client};
+ my $file = $Wallet::Config::KEYTAB_TMP . "/keytab.$$";
+ unlink $file;
+ my $princdata = eval { $kadmin->getPrincipal ($principal) };
+ if ($@) {
+ $self->error ("error creating keytab for $principal: $@");
+ return;
+ } elsif (!$princdata) {
+ $self->error ("error creating keytab for $principal: principal does"
+ . " not exist");
+ return;
+ }
+ eval { $kadmin->extractKeytab ($princdata, $file) };
+ if ($@) {
+ $self->error ("error creating keytab for principal: $@");
+ return;
+ }
+ my $data = $self->slurp_file ($file);
+ unlink $file;
+ return $data;
+}
+
+# Create a keytab for a principal, randomizing the keys for that principal at
+# the same time. Takes the principal, the file, and optionally a list of
+# encryption types to which to limit the keytab. Return true if successful,
+# false otherwise. If the keytab creation fails, sets the error.
+sub keytab_rekey {
my ($self, $principal, $file, @enctypes) = @_;
$principal = $self->canonicalize_principal ($principal);
@@ -213,10 +257,12 @@ Wallet::Kadmin::Heimdal - Wallet Kerberos administration API for Heimdal
=head1 SYNOPSIS
my $kadmin = Wallet::Kadmin::Heimdal->new;
- $kadmin->create ("host/foo.example.com");
- $kadmin->keytab ("host/foo.example.com", "aes256-cts-hmac-sha1-96");
- my $exists = $kadmin->exists ("host/oldshell.example.com");
- $kadmin->destroy ("host/oldshell.example.com") if $exists;
+ $kadmin->create ('host/foo.example.com');
+ $kadmin->keytab_rekey ('host/foo.example.com', 'keytab',
+ 'aes256-cts-hmac-sha1-96');
+ my $data = $kadmin->keytab ('host/foo.example.com');
+ my $exists = $kadmin->exists ('host/oldshell.example.com');
+ $kadmin->destroy ('host/oldshell.example.com') if $exists;
=head1 DESCRIPTION
@@ -228,6 +274,18 @@ To use this object, several configuration parameters must be set. See
Wallet::Config(3) for details on those configuration parameters and
information about how to set wallet configuration.
+=head1 FILES
+
+=over 4
+
+=item KEYTAB_TMP/keytab.<pid>
+
+The keytab is created in this file and then read into memory. KEYTAB_TMP
+is set in the wallet configuration, and <pid> is the process ID of the
+current process. The file is unlinked after being read.
+
+=back
+
=head1 SEE ALSO
kadmin(8), Wallet::Config(3), Wallet::Kadmin(3),
diff --git a/perl/Wallet/Kadmin/MIT.pm b/perl/Wallet/Kadmin/MIT.pm
index 9ab575c..1c6d2c1 100644
--- a/perl/Wallet/Kadmin/MIT.pm
+++ b/perl/Wallet/Kadmin/MIT.pm
@@ -137,11 +137,52 @@ sub create {
return 1;
}
-# Create a keytab from a principal. Takes the principal, the file, and
-# optionally a list of encryption types to which to limit the keytab. Return
-# true if successful, false otherwise. If the keytab creation fails, sets the
-# error.
+# Retrieve an existing keytab from the KDC via a remctl call. The KDC needs
+# to be running the keytab-backend script and support the keytab retrieve
+# remctl command. In addition, the user must have configured us with the path
+# to a ticket cache and the host to which to connect with remctl. Returns the
+# keytab on success and undef on failure.
sub keytab {
+ my ($self, $principal) = @_;
+ my $host = $Wallet::Config::KEYTAB_REMCTL_HOST;
+ unless ($host and $Wallet::Config::KEYTAB_REMCTL_CACHE) {
+ $self->error ('keytab unchanging support not configured');
+ return;
+ }
+ eval { require Net::Remctl };
+ if ($@) {
+ $self->error ("keytab unchanging support not available: $@");
+ return;
+ }
+ if ($principal !~ /\@/ && $Wallet::Config::KEYTAB_REALM) {
+ $principal .= '@' . $Wallet::Config::KEYTAB_REALM;
+ }
+ local $ENV{KRB5CCNAME} = $Wallet::Config::KEYTAB_REMCTL_CACHE;
+ my $port = $Wallet::Config::KEYTAB_REMCTL_PORT || 0;
+ my $remctl_princ = $Wallet::Config::KEYTAB_REMCTL_PRINCIPAL || '';
+ my @command = ('keytab', 'retrieve', $principal);
+ my $result = Net::Remctl::remctl ($host, $port, $remctl_princ, @command);
+ if ($result->error) {
+ $self->error ("cannot retrieve keytab for $principal: ",
+ $result->error);
+ return;
+ } elsif ($result->status != 0) {
+ my $error = $result->stderr;
+ $error =~ s/\s+$//;
+ $error =~ s/\n/ /g;
+ $self->error ("cannot retrieve keytab for $principal: $error");
+ return;
+ } else {
+ return $result->stdout;
+ }
+}
+
+# Create a keytab for a principal, randomizing the keys for that principal
+# in the process. Takes the principal, the file, and optionally a list of
+# encryption types to which to limit the keytab. Return true if
+# successful, false otherwise. If the keytab creation fails, sets the
+# error.
+sub keytab_rekey {
my ($self, $principal, $file, @enctypes) = @_;
unless ($self->valid_principal ($principal)) {
$self->error ("invalid principal name: $principal");
@@ -210,7 +251,7 @@ __END__
##############################################################################
=for stopwords
-keytabs keytab kadmin KDC API Allbery
+rekeying rekeys remctl backend keytabs keytab kadmin KDC API Allbery
=head1 NAME
@@ -219,10 +260,12 @@ Wallet::Kadmin::MIT - Wallet Kerberos administration API for MIT
=head1 SYNOPSIS
my $kadmin = Wallet::Kadmin::MIT->new;
- $kadmin->create ("host/foo.example.com");
- $kadmin->keytab ("host/foo.example.com", "aes256-cts-hmac-sha1-96");
- my $exists = $kadmin->exists ("host/oldshell.example.com");
- $kadmin->destroy ("host/oldshell.example.com") if $exists;
+ $kadmin->create ('host/foo.example.com');
+ $kadmin->keytab_rekey ('host/foo.example.com', 'keytab',
+ 'aes256-cts-hmac-sha1-96');
+ my $data = $kadmin->keytab ('host/foo.example.com');
+ my $exists = $kadmin->exists ('host/oldshell.example.com');
+ $kadmin->destroy ('host/oldshell.example.com') if $exists;
=head1 DESCRIPTION
@@ -231,6 +274,13 @@ providing an interface to create and delete principals and create keytabs.
It provides the API documented in Wallet::Kadmin(3) for an MIT Kerberos
KDC.
+MIT Kerberos does not provide any method via the kadmin network protocol
+to retrieve a keytab for a principal without rekeying it, so the keytab()
+method (as opposed to keytab_rekey(), which rekeys the principal) is
+implemented using a remctl backend. For that method (used for unchanging
+keytab objects) to work, the necessary wallet configuration and remctl
+interface on the KDC must be set up.
+
To use this object, several configuration parameters must be set. See
Wallet::Config(3) for details on those configuration parameters and
information about how to set wallet configuration.