From ee43823179ee627ac16ea9da8168e5f1bf9619c0 Mon Sep 17 00:00:00 2001
From: "Jannis M. Hoffmann" <jannis.hoffmann@rwth-aachen.de>
Date: Thu, 29 Oct 2020 12:13:04 +0100
Subject: Initial commit; Stable version

---
 lib/JWebmail/Plugin/Helper.pm | 448 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 448 insertions(+)
 create mode 100644 lib/JWebmail/Plugin/Helper.pm

(limited to 'lib/JWebmail/Plugin/Helper.pm')

diff --git a/lib/JWebmail/Plugin/Helper.pm b/lib/JWebmail/Plugin/Helper.pm
new file mode 100644
index 0000000..5e557d1
--- /dev/null
+++ b/lib/JWebmail/Plugin/Helper.pm
@@ -0,0 +1,448 @@
+package JWebmail::Plugin::Helper;
+
+use Mojo::Base 'Mojolicious::Plugin';
+
+use POSIX qw(floor round log ceil);
+use MIME::Base64;
+use Encode;
+use Mojo::Util 'xml_escape';
+use List::Util qw(min max);
+
+use constant TRUE_RANDOM => eval { require Crypt::Random; Crypt::Random->import('makerandom_octet'); 1 };
+use constant HMAC => eval { require Digest::HMAC_MD5; Digest::HMAC_MD5->import('hmac_md5'); 1 };
+
+### filter and checks for mojo validator
+
+sub mail_line {
+    my ($v, $name, $value, @args) = @_;
+
+    my $mail_addr = qr/\w+\@\w+\.\w+/;
+    # my $unescaped_quote = qr/"(*nlb:\\)/; # greater perl version required
+    my $unescaped_quote = qr/"(?<!:\\)/;
+
+    return $value !~ /^(
+        (
+            (
+                (
+                    $unescaped_quote.*?$unescaped_quote
+                ) | (
+                    [\w\s]*
+                )
+            )
+            \s*<$mail_addr>
+        ) | (
+            $mail_addr
+        ))$
+    /xno;
+}
+
+
+sub filter_empty_upload {
+    my ($v, $name, $value) = @_;
+
+    return $value->filename ? $value : undef;
+}
+
+### template formatting functions
+
+sub print_sizes10 {
+    my $var = shift;
+    if ($var == 0) { return '0 Byte'; }
+
+    my $i = floor(((log($var)/log(10))+1e-5) / 3);
+    my $expo = $i * 3;
+
+    my @PREFIX;
+    $PREFIX[0] = 'Byte';
+    $PREFIX[1] = 'kByte';
+    $PREFIX[2] = 'MByte';
+    $PREFIX[3] = 'GByte';
+    $PREFIX[4] = 'TByte';
+    $PREFIX[5] = 'PByte';
+
+    return sprintf('%.0f %s', $var / (10**$expo), $PREFIX[$i]);
+}
+
+
+sub print_sizes2 {
+    my $var = shift;
+    if ($var == 0) { return '0 Byte'; }
+
+    my $i = floor(((log($var)/log(2))+1e-5) / 10);
+    my $expo = $i * 10;
+    my %PREFIX = (
+        0 => 'Byte',
+        1 => 'KiByte',
+        2 => 'MiByte',
+        3 => 'GiByte',
+        4 => 'TiByte',
+        5 => 'PiByte',
+    );
+    my $pref = $PREFIX{$i};
+    return round($var / (2**$expo)) . " $pref";
+}
+
+### mime type html render functions
+
+my $render_text_plain = sub {
+    my ($c, $content) = @_;
+
+    $content = xml_escape($content);
+    $content =~ s/\n/<br>/g;
+
+    return $content;
+};
+
+
+my $render_text_html = sub {
+    my $c_ = shift;
+
+    return '<iframe src="' . $c_->url_for('rawid', id => $c_->stash('id'))->query(body => 'html') . '" class=html-mail />';
+};
+
+
+our %MIME_Render_Subs = (
+    'text/plain' => $render_text_plain,
+    'text/html'  => $render_text_html,
+);
+
+
+sub mime_render {
+    my ($c, $enc, $cont) = @_;
+
+    my $renderer = $MIME_Render_Subs{$enc};
+    return '' unless defined $renderer;
+    return $renderer->($c, $cont);
+};
+
+### session password handling
+
+use constant { S_PASSWD => 'pw', S_OTP_S3D_PW => 'otp_s3d_pw' };
+
+sub _rand_data {
+    my $len = shift;
+
+    return makerandom_octet(Length => $len, Strength => 0);
+}
+
+sub _pseudo_rand_data {
+    my $len = shift;
+
+    my $res = '';
+    for (0..$len-1) {
+        vec($res, $_, 8) = int rand 256;
+    }
+
+    return $res;
+}
+
+sub session_passwd {
+    my ($c, $passwd) = @_;
+
+    warn_cram($c);
+    warn_crypt($c);
+
+    if (defined $passwd) { # set
+        if ( HMAC && lc($c->config->{'session'}{secure} || 'none') eq 'cram' ) {
+            $c->session(S_PASSWD() => $passwd ? encode_base64(hmac_md5($passwd, $c->app->secrets->[0]), '') : '');
+        }
+        elsif (lc($c->config->{'session'}->{secure} || 'none') eq 's3d') {
+            unless ($passwd) {
+                $c->s3d(S_PASSWD, '');
+                delete $c->session->{S_OTP_S3D_PW()};
+                return;
+            }
+            die "'$passwd' contains invalid character \\n" if $passwd =~ /\n/; 
+            if (length $passwd < 20) {
+                $passwd .= "\n" . " " x (20 - length($passwd) - 1);
+            }
+            my $rand_bytes = TRUE_RANDOM ? _rand_data(length $passwd) : _pseudo_rand_data(length $passwd);
+            $c->s3d(S_PASSWD, encode_base64(encode('UTF-8', $passwd) ^ $rand_bytes, ''));
+            $c->session(S_OTP_S3D_PW, encode_base64($rand_bytes, ''));
+        }
+        else {
+            $c->session(S_PASSWD() => $passwd);
+        }
+    }
+    else { # get
+        if ( HMAC && lc($c->config->{'session'}->{secure} || 'none') eq 'cram' ) {
+            return ($c->app->secrets->[0], $c->session(S_PASSWD));
+        }
+        elsif (lc($c->config->{'session'}->{secure} || 'none') eq 's3d') {
+            my $pw = decode_base64($c->s3d(S_PASSWD) || '');
+            my $otp = decode_base64($c->session(S_OTP_S3D_PW) || '');
+            my ($res) = split "\n", decode('UTF-8', $pw ^ $otp), 2;
+            return $res;
+        }
+        else {
+            return $c->session(S_PASSWD);
+        }
+    }
+}
+
+sub warn_cram {
+    my $c = shift;
+
+    state $once = 0;
+
+    if ( !HMAC && !$once && lc($c->config->{'session'}->{secure} || 'none') eq 'cram' ) {
+        $c->log->warn("cram requires Digest::HMAC_MD5. Falling back to 'none'.");
+    }
+
+    $once = 1;
+}
+
+sub warn_crypt {
+    my $c = shift;
+
+    state $once = 0;
+
+    if ( !TRUE_RANDOM && !$once && lc($c->config->{'session'}->{secure} || 'none') eq 's3d' ) {
+        $c->log->warn("Falling back to pseudo random generation. Please install Crypt::Random");
+    }
+
+    $once = 1;
+}
+
+### pagination
+
+sub _clamp {
+    my ($x, $y, $z) = @_;
+
+    die '!($x <= $z)' unless $x <= $z;
+
+    if ($x <= $y && $y <= $z) {
+        return $y;
+    }
+
+    return $x if ($y < $x);
+    return $z if ($z < $y);
+}
+
+sub _paginate {
+    my %args = @_;
+
+    my $first_item  = $args{first_item};
+    my $page_size   = $args{page_size} || 1;
+    my $total_items = $args{total_items};
+
+    my $first_item1 = $total_items ? $first_item+1 : 0;
+
+    my $current_page = ceil($first_item/$page_size);
+    my $total_pages  = ceil($total_items/$page_size);
+
+    my $page = sub {
+        my $page_ = shift;
+        return [0, 0] unless $total_items;
+        $page_ = _clamp(0, $page_, $total_pages-1);
+        [_clamp(1, $page_*$page_size + 1, $total_items), _clamp(1, ($page_+1)*$page_size, $total_items)]
+    };
+
+    return (
+        first_item  => $first_item1,
+        last_item   => _clamp($first_item1, $first_item + $page_size, $total_items),
+        total_items => $total_items,
+        page_size   => $page_size,
+
+        total_pages  => $total_pages,
+        current_page => $current_page + 1,
+
+        first_page => $page->(0),
+        prev_page  => $page->($current_page-1),
+        next_page  => $page->($current_page+1),
+        last_page  => $page->($total_pages-1),
+    );
+}
+
+sub paginate {
+    my $c = shift;
+    my $count = shift;
+
+    my $v = $c->validation;
+    my $start = $v->optional('start')->num(0, undef)->param // 0;
+    my $psize = $v->optional('page_size')->num(1, undef)->param // 50;
+
+    $start = _clamp(0, $start, max($count-1, 0));
+    my $end = _clamp($start, $start+$psize-1, max($count-1, 0));
+
+    $c->stash(_paginate(first_item => $start, page_size => $psize, total_items => $count));
+
+    return $start, $end;
+}
+
+### registering
+
+sub register {
+    my ($self, $app, $conf) = @_;
+
+    if (ref $conf->{import} eq 'ARRAY' and my @import = @{ $conf->{import} }) {
+        no warnings 'experimental::smartmatch';
+
+        # selective import
+        $app->helper(print_sizes10  => sub { shift; print_sizes10(@_) })
+            if 'print_sizes10' ~~ @import;
+        $app->helper(print_sizes2  => sub { shift; print_sizes2(@_) })
+            if 'print_sizes2' ~~ @import;
+        $app->helper(mime_render    => \&mime_render)
+            if 'mime_render' ~~ @import;
+        $app->helper(session_passwd => \&session_passwd)
+            if 'session_passwd' ~~ @import;
+        $app->helper(paginate => \&paginate)
+            if 'paginate' ~~ @import;
+        $app->validator->add_check(mail_line => \&mail_line)
+            if 'mail_line' ~~ @import;
+        $app->validator->add_filter(non_empty_ul => \&filter_empty_upload)
+            if 'non_empty_ul' ~~ @import;
+    }
+    elsif (!$conf->{import}) { # default imports
+        $app->helper(print_sizes10  => sub { shift; print_sizes10(@_) });
+        $app->helper(mime_render    => \&mime_render);
+        $app->helper(session_passwd => \&session_passwd);
+        $app->helper(paginate       => \&paginate);
+
+        $app->validator->add_check(mail_line => \&mail_line);
+
+        $app->validator->add_filter(non_empty_ul => \&filter_empty_upload);
+    }
+}
+
+
+1
+
+__END__
+
+=encoding utf-8
+
+=head1 NAME
+
+Helper - Functions used as helpers in controller and templates and additional validator checks and filters
+
+=head1 SYNOPSIS
+
+  use Mojo::Base 'Mojolicious';
+
+  use JWebmail::Plugin::Helper;
+
+  sub startup($self) {
+    $self->helper(mime_render => \&JWebmail::Plugin::Helper::mime_render);
+  }
+
+  # or
+
+  $app->plugin('Helper');
+
+=head1 DESCRIPTION
+
+L<JWebmail::Helper> provides useful helper functions and validator cheks and filter for
+L<JWebmail::Controller::All> and various templates.
+
+=head1 FUNCTIONS
+
+=head2 mail_line
+
+A check for validator used in mail headers for fields containing email addresses.
+
+  $app->validator->add_check(mail_line => \&JWebmail::Plugin::Helper::mail_line);
+
+  my $v = $c->validation;
+  $v->required('to', 'not_empty')->check('mail_line');
+
+=head2 filter_empty_upload
+
+A filter for validator used to filter out empty uploads.
+
+  $app->validator->add_filter(non_empty_ul => \&JWebmail::Plugin::Helper::filter_empty_upload);
+
+  my $v = $c->validation;
+  $v->required('file_upload', 'non_empty_ul');
+
+=head2 print_sizes10
+
+A helper for templates used to format byte sizes.
+
+  $app->helper(print_sizes10 => sub { shift; JWebmail::Plugin::Helper::print_sizes10(@_) });
+
+  %= print_sizes10 12345 # => 12 kB
+
+=head2 print_sizes2
+
+A helper for templates used to format byte sizes.
+
+  %= print_sizes10 12345 # => 12 KiB
+
+This is not registered by default.
+
+=head2 paginate
+
+A helper for calculationg page bounds.
+
+Takes the total number of items as argument.
+
+Reads in 'start' and 'page_size' query arguments.
+start is 0 based.
+
+Returns the calculated start and end points as 0 based inclusive range.
+
+Sets the stash values (all 1 based inclusive):
+
+  first_item
+  last_item
+  total_items
+  page_size
+  total_pages
+  current_page
+  first_page
+  prev_page
+  next_page
+  last_page
+
+=head2 mime_render
+
+A helper for templates used to display the content of a mail for the browser.
+The output is valid html and should not be escaped.
+
+  $app->helper(mime_render => \&JWebmail::Plugin::Helper::mime_render);
+
+  %== mime_render 'text/plain' $content
+
+=head2 session_passwd
+
+A helper used to set and get the session password. The behaivour can be altered by
+setting the config variable C<< session => {secure => 's3d'} >>.
+
+  $app->helper(session_passwd => \&JWebmail::Plugin::Helper::session_passwd);
+
+  $c->session_passwd('s3cret');
+
+Currently the following modes are supported:
+
+=over 6
+
+=item none 
+
+password is plainly stored in session cookie
+
+=item cram 
+
+challenge response authentication mechanism uses the C<< $app->secret->[0] >> as nonce.
+This is optional if Digest::HMAC_MD5 is installed.
+
+=item s3d 
+
+data is stored on the server. Additionally the password is encrypted by an one-time-pad that is stored in the user cookie.
+
+=back
+
+=head1 DEPENDENCIES
+
+Mojolicious, Crypt::Random and optianally Digest::HMAC_MD5.
+
+=head1 SEE ALSO
+
+L<JWebmail>, L<JWebmail::Controller::All>, L<Mojolicious>, L<Mojolicious::Controller>
+
+=head1 NOTICE
+
+This package is part of JWebmail.
+
+=cut
\ No newline at end of file
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