Simple login screen.

3 files changed, 326 insertions, 0 deletions

diff --git a/lib/Fripost.pm b/lib/Fripost.pm
new file mode 100644
index 0000000..93531f9
--- /dev/null
+++ b/lib/Fripost.pm
@@ -0,0 +1,114 @@
+#----------------------------------------------------------------------
+# Fripost tools - backend library
+# Copyright © 2012-2018 Fripost
+# Copyright © 2012-2018 Guilhem Moulin <guilhem@fripost.org>
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#----------------------------------------------------------------------
+
+package Fripost v0.0.1;
+use warnings;
+use strict;
+
+use Net::LDAP ();
+use Net::LDAP::Constant qw/LDAP_SUCCESS LDAP_INVALID_CREDENTIALS/;
+use Net::LDAP::Extension::WhoAmI ();
+use Net::LDAP::Util "escape_dn_value";
+use Net::IDN::Encode "domain_to_ascii";
+
+
+########################################################################
+#
+
+# new(OPTION => VALUE)
+#   Create a new Fripost object.
+sub new($%) {
+    my $class = shift;
+    my %conf = @_;
+    my $uri = $conf{ldap}->{uri} // die;
+    my $fpr = $conf{ldap}->{"ssl-fingerprint"};
+
+    my %args = ( raw => qr/(?:^fripostOpenPGPKeyring\b|;binary$)/i );
+    $args{verify} //= ($uri =~ /\Aldaps:\/\// and not defined $fpr) ? "require" : "none";
+    my $ldap = Net::LDAP::->new($uri, %args) // die "LDAP connection to $uri failed";
+
+    if (defined $fpr) {
+        my $cert = $ldap->certificate->peer_certificate;
+        die("Aborting LDAP connection to $uri: fingerprint mismatch")
+            unless $fpr->( Net::SSLeay::X509_get_X509_PUBKEY($cert) );
+    }
+    undef $conf{ldap}->{suffix} if ($conf{ldap}->{suffix} // "") eq "";
+    bless {_ldap => $ldap, _config => \%conf}, $class;
+}
+
+sub DESTROY {
+    my $ldap = shift->{_ldap} // return;
+    $ldap->unbind();
+}
+
+# croak(FORMAT, [ARG..])
+#   Format the message and throw an exception.
+sub croak($$@) {
+    my $self = shift;
+    my $format = shift;
+    if (defined (my $throw = $self->{_config}->{onerror})) {
+        $throw->($format, @_);
+    } else {
+        $format =~ s/[A-Z]<(%\p{PosixAlpha})>/$1/g; # Remove all markup
+        die sprintf("Error: ".$format, @_);
+    }
+}
+
+# login(USER@DOMAIN, PASSWORD)
+#   Login to the LDAP backend (with a simple bind).  LDAP errors other
+#   than 49 (INVALID_CREDENTIALS) are treated as internal backend
+#   errors and shown to the user.
+sub login($$$) {
+    my ($self, $username, $password) = @_;
+
+    # convert IDNA domain names to ASCII
+    my ($l, $d) = ($1, $2)
+        if $username =~ /\A(\p{ASCII}*)[\@\N{U+FE6B}\N{U+FF20}](.*)\z/;
+    eval { $d = domain_to_ascii($d) if defined $d and $d =~ /\P{ASCII}/ };
+    $self->croak("Invalid username: C<%s>\n", $username // "")
+        if $@ or ($l // "") eq "" or ($d // "") eq "";
+
+    my $dn = "fvl=".escape_dn_value($l).",fvd=".escape_dn_value($d);
+    $dn .= ",".$self->{_config}->{ldap}->{suffix}
+        if defined $self->{_config}->{ldap}->{suffix};
+
+    my $r = $self->{_ldap}->bind($dn, password => $password);
+    if ($r->code == LDAP_INVALID_CREDENTIALS) {
+        $self->croak("Invalid username or password.\n");
+    } elsif ($r->code != LDAP_SUCCESS) {
+        $self->croak("LDAP error code %i: %s\n", $r->code, $r->error);
+    }
+}
+
+# whoami()
+#   Perform the LDAP "Who Am I?" (RFC 4532) extended operation.
+sub whoami($) {
+    my $self = shift;
+
+    my $dse = $self->{_ldap}->root_dse();
+    $self->croak("LDAP server doesn't support \"Who am I?\" operation.")
+        unless $dse->supported_extension("1.3.6.1.4.1.4203.1.11.3");
+
+    my $r = $self->{_ldap}->who_am_i();
+    $self->croak("LDAP error code %i: %s\n", $r->code, $r->error)
+        unless $r->code == LDAP_SUCCESS;
+    return $r->response();
+}
+
+1;
diff --git a/lib/Fripost/Session.pm b/lib/Fripost/Session.pm
new file mode 100644
index 0000000..888385f
--- /dev/null
+++ b/lib/Fripost/Session.pm
@@ -0,0 +1,122 @@
+#----------------------------------------------------------------------
+# Fripost admin panel - ephemeral sessions
+# Copyright © 2018 Fripost
+# Copyright © 2018 Guilhem Moulin <guilhem@fripost.org>
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#----------------------------------------------------------------------
+
+package Fripost::Session v0.0.1;
+use warnings;
+use strict;
+
+use Authen::SASL ();
+use Net::LDAP::Constant qw/LDAP_SUCCESS LDAP_ALREADY_EXISTS/;
+use Net::LDAP::Extension::Refresh ();
+use Net::LDAP::Util "escape_dn_value";
+
+use Crypt::URandom "urandom";
+
+use Fripost ();
+
+
+# create(Fripost object)
+#   Create a new ephemeral session from a Fripost object, and return
+#   suitable credentials for later SASL proxy authorization.
+sub create($$) {
+    my ($class, $fp) = @_;
+
+    # don't base64-encode but hex-encode as the commonName is case-insensitive
+    my $id  = unpack("H*", urandom(16));
+    my $dn = sprintf($fp->{_config}->{ldap}->{"session-authcDN"},
+                escape_dn_value($id));
+    # hex-encode the password too since we can't have NUL bytes in the SASL packet
+    my $password = unpack("H*", urandom(16));
+
+    my $authzid = $fp->whoami() // die;
+    die "Invalid identity: $authzid\n" unless $authzid =~ /\Adn:/;
+
+    my @attrs = (objectClass => [ qw/organizationalRole simpleSecurityObject dynamicObject/ ]);
+    # libsasl2 requires {CLEARTEXT} passwords, even for PLAIN, cf.
+    # https://openldap.org/lists/openldap-technical/201310/msg00007.html
+    # (not a big deal here though since our shared secrets are internal
+    # and ephemeral)
+    push @attrs, userPassword => ( "{CLEARTEXT}" . $password );
+
+    my $r = $fp->{_ldap}->add($dn, attrs => \@attrs);
+    if ($r->code == LDAP_ALREADY_EXISTS) {
+        # try to delete the entry (we're not allowed to modify existing entries)
+        my $r2 = $fp->{_ldap}->delete($dn);
+        $r = $fp->{_ldap}->add($dn, attrs => \@attrs)
+            if $r2->code == LDAP_SUCCESS;
+    }
+    $fp->croak("LDAP error code %i: %s\n", $r->code, $r->error)
+        unless $r->code == LDAP_SUCCESS;
+
+    my %creds = (authcid => $id, password => $password, authzid => $authzid);
+    bless \%creds, $class;
+}
+
+# authenticate(CREDENTIALS, OPTION => VALUE, ..)
+#   Create a new Fripost object and return it after authentication
+#   (using SASL proxy authorization with the ephemeral credentials).
+#   If the "refresh" is set (the default), then TTL value of the entry
+#   on the backup is refreshed.
+sub authenticate($%) {
+    my $creds = shift;
+    my %conf = @_;
+
+    my $refresh = delete $conf{refresh} // 1;
+    my $authcid = sprintf($conf{ldap}->{"session-authcID"} // "%s",
+            $creds->{authcid});
+
+    my $sasl = Authen::SASL::->new( mechanism => "PLAIN", callback  => {
+         user => $authcid
+       , pass => $creds->{password}
+       , authname => $creds->{authzid}
+    }) or die "Creation of Authen::SASL object failed";
+
+    my $fp = Fripost::->new(%conf);
+    my $r = $fp->{_ldap}->bind(undef, sasl => $sasl);
+    $fp->croak("LDAP error code %i: %s\n", $r->code, $r->error)
+        unless $r->code == LDAP_SUCCESS;
+    
+    if ($refresh) {
+        my $dn = sprintf($conf{ldap}->{"session-authcDN"} // "%s",
+            escape_dn_value($creds->{authcid}));
+        my $ttl = $conf{www}->{"cache-expires"};
+        $r = $fp->{_ldap}->refresh(entryName => $dn, requestTtl => $ttl);
+        $fp->croak("LDAP error code %i: %s\n", $r->code, $r->error)
+            unless $r->code == LDAP_SUCCESS;
+    }
+    return $fp;
+}
+
+# authenticate(CREDENTIALS, OPTION => VALUE, ..)
+#   Create a new Fripost object, authenticate (using SASL proxy
+#   authorization), and delete the entry on the LDAP backend.
+sub destroy($%) {
+    my $creds = shift;
+    my %conf = @_;
+
+    my $dn = sprintf($conf{ldap}->{"session-authcDN"} // "%s",
+        escape_dn_value($creds->{authcid}));
+
+    my $fp = authenticate($creds, %conf, refresh => 0);
+    my $r = $fp->{_ldap}->delete($dn);
+    $fp->croak("LDAP error code %i: %s\n", $r->code, $r->error)
+        unless $r->code == LDAP_SUCCESS;
+}
+
+1;
diff --git a/lib/Fripost/Util.pm b/lib/Fripost/Util.pm
new file mode 100644
index 0000000..6fa55a5
--- /dev/null
+++ b/lib/Fripost/Util.pm
@@ -0,0 +1,90 @@
+#----------------------------------------------------------------------
+# Fripost utils
+# Copyright © 2018 Fripost
+# Copyright © 2018 Guilhem Moulin <guilhem@fripost.org>
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#----------------------------------------------------------------------
+
+package Fripost::Util v0.0.1;
+use warnings;
+use strict;
+
+use Config::Tiny ();
+use MIME::Base64 qw/encode_base64 decode_base64/;
+
+use Exporter "import";
+BEGIN {
+    our @EXPORT_OK = qw/read_config session_cache/;
+}
+
+
+# read_config()
+#   Read the configuration file.
+sub read_config() {
+    my $filename = "./config.ini";
+    my $h = Config::Tiny::->read($filename, "utf8");
+    die Config::Tiny::->errstr(), "\n" unless defined $h;
+
+    my $ldap = $h->{ldap} // die "Missing [ldap] section";
+    $ldap->{uri} //= "ldapi://";
+
+    # replace "ssl-fingerprint" with a function taking an SPKI and
+    # verifying its fingerprint
+    my $fpr = delete $ldap->{"ssl-fingerprint"}
+        if $ldap->{uri} =~ /\Aldaps:\/\//;
+    if (defined $fpr) {
+        die "Invalid value: $fpr" unless $fpr =~ s/\A([A-Za-z0-9]+)=//;
+        my $algo = $1;
+
+        my $digest = decode_base64($fpr);
+        die "Invalid base64 value: $fpr\n"
+            # decode_base64() silently ignores invalid characters so we
+            # re-encode the output to validate it
+            unless encode_base64($digest, "") eq $fpr and $fpr ne "";
+
+        require "Net/SSLeay.pm";
+        my $type = Net::SSLeay::EVP_get_digestbyname($algo) or
+            die "Can't find MD value for name '$algo'";
+        $ldap->{"ssl-fingerprint"} = sub($) {
+            my $pkey = shift // return 0;
+            return (Net::SSLeay::EVP_Digest($pkey, $type) eq $digest) ? 1 : 0;
+        };
+    }
+
+    $h->{www} //= {};
+    $h->{www}->{"cache-expires"} //= "3600";
+    return %$h;
+}
+
+
+# session_cache(%CONFIG)
+#   Define a new CHI object for the server-side session store.
+sub session_cache(%) {
+    my %www_config = @_;
+    require "CHI.pm";
+
+    my %cache_opts;
+    $cache_opts{root_dir} = $www_config{"cache-directory"};
+    $cache_opts{dir_create_mode} = 0700;
+    $cache_opts{namespace} = "fripost";
+
+    CHI->new(
+        driver => "FastMmap" # use Cache::FastMmap
+      , %cache_opts
+      , expires_in => $www_config{"cache-expires"}
+    );
+}
+
+1;