nntp: NNTPS and NNTP+STARTTLS working

It kinda, barely works, and I'm most happy I got it working
without any modifications to the main NNTP::event_step callback
thanks to the DS->write(CODE) support we inherited from
Danga::Socket.

11 files changed, 450 insertions, 13 deletions

diff --git a/MANIFEST b/MANIFEST
index c7693976..26ff0d0d 100644
--- a/MANIFEST
+++ b/MANIFEST
@@ -31,6 +31,8 @@ MANIFEST
 Makefile.PL
 README
 TODO
+certs/.gitignore
+certs/create-certs.perl
 ci/README
 ci/deps.perl
 ci/profiles.sh
@@ -129,6 +131,7 @@ lib/PublicInbox/Spamcheck/Spamc.pm
 lib/PublicInbox/Spawn.pm
 lib/PublicInbox/SpawnPP.pm
 lib/PublicInbox/Syscall.pm
+lib/PublicInbox/TLS.pm
 lib/PublicInbox/Unsubscribe.pm
 lib/PublicInbox/UserContent.pm
 lib/PublicInbox/V2Writable.pm
@@ -222,6 +225,7 @@ t/msg_iter.t
 t/msgmap.t
 t/msgtime.t
 t/nntp.t
+t/nntpd-tls.t
 t/nntpd.t
 t/nulsubject.t
 t/over.t
diff --git a/certs/.gitignore b/certs/.gitignore
new file mode 100644
index 00000000..0b3a547b
--- /dev/null
+++ b/certs/.gitignore
@@ -0,0 +1,4 @@
+*.pem
+*.der
+*.enc
+*.p12
diff --git a/certs/create-certs.perl b/certs/create-certs.perl
new file mode 100755
index 00000000..bfd8e5f1
--- /dev/null
+++ b/certs/create-certs.perl
@@ -0,0 +1,132 @@
+#!/usr/bin/perl -w
+# License: GPL-1.0+ or Artistic-1.0-Perl
+# from IO::Socket::SSL 2.063 / https://github.com/noxxi/p5-io-socket-ssl
+use strict;
+use warnings;
+use IO::Socket::SSL::Utils;
+use Net::SSLeay;
+
+my $dir = "./";
+my $now = time();
+my $later = $now + 100*365*86400;
+
+Net::SSLeay::SSLeay_add_ssl_algorithms();
+my $sha256 = Net::SSLeay::EVP_get_digestbyname('sha256') or die;
+my $printfp = sub {
+    my ($w,$cert) = @_;
+    print $w.' sha256$'.unpack('H*',Net::SSLeay::X509_digest($cert, $sha256))."\n"
+};
+
+my %time_valid = (not_before => $now, not_after => $later);
+
+my @ca = CERT_create(
+    CA => 1,
+    subject => { CN => 'IO::Socket::SSL Demo CA' },
+    %time_valid,
+);
+save('test-ca.pem',PEM_cert2string($ca[0]));
+
+my @server = CERT_create(
+    CA => 0,
+    subject => { CN => 'server.local' },
+    purpose => 'server',
+    issuer => \@ca,
+    %time_valid,
+);
+save('server-cert.pem',PEM_cert2string($server[0]));
+save('server-key.pem',PEM_key2string($server[1]));
+$printfp->(server => $server[0]);
+
+@server = CERT_create(
+    CA => 0,
+    subject => { CN => 'server2.local' },
+    purpose => 'server',
+    issuer => \@ca,
+    %time_valid,
+);
+save('server2-cert.pem',PEM_cert2string($server[0]));
+save('server2-key.pem',PEM_key2string($server[1]));
+$printfp->(server2 => $server[0]);
+
+@server = CERT_create(
+    CA => 0,
+    subject => { CN => 'server-ecc.local' },
+    purpose => 'server',
+    issuer => \@ca,
+    key => KEY_create_ec(),
+    %time_valid,
+);
+save('server-ecc-cert.pem',PEM_cert2string($server[0]));
+save('server-ecc-key.pem',PEM_key2string($server[1]));
+$printfp->('server-ecc' => $server[0]);
+
+
+my @client = CERT_create(
+    CA => 0,
+    subject => { CN => 'client.local' },
+    purpose => 'client',
+    issuer => \@ca,
+    %time_valid,
+);
+save('client-cert.pem',PEM_cert2string($client[0]));
+save('client-key.pem',PEM_key2string($client[1]));
+$printfp->(client => $client[0]);
+
+my @swc = CERT_create(
+    CA => 0,
+    subject => { CN => 'server.local' },
+    purpose => 'server',
+    issuer => \@ca,
+    subjectAltNames => [
+        [ DNS => '*.server.local' ],
+        [ IP => '127.0.0.1' ],
+        [ DNS => 'www*.other.local' ],
+        [ DNS => 'smtp.mydomain.local' ],
+        [ DNS => 'xn--lwe-sna.idntest.local' ]
+    ],
+    %time_valid,
+);
+save('server-wildcard.pem',PEM_cert2string($swc[0]),PEM_key2string($swc[1]));
+
+
+my @subca = CERT_create(
+    CA => 1,
+    issuer => \@ca,
+    subject => { CN => 'IO::Socket::SSL Demo Sub CA' },
+    %time_valid,
+);
+save('test-subca.pem',PEM_cert2string($subca[0]));
+@server = CERT_create(
+    CA => 0,
+    subject => { CN => 'server.local' },
+    purpose => 'server',
+    issuer => \@subca,
+    %time_valid,
+);
+save('sub-server.pem',PEM_cert2string($server[0]).PEM_key2string($server[1]));
+
+
+
+my @cap = CERT_create(
+    CA => 1,
+    subject => { CN => 'IO::Socket::SSL::Intercept' },
+    %time_valid,
+);
+save('proxyca.pem',PEM_cert2string($cap[0]).PEM_key2string($cap[1]));
+
+sub save {
+    my $file = shift;
+    open(my $fd,'>',$dir.$file) or die $!;
+    print $fd @_;
+}
+
+system(<<CMD);
+cd $dir
+set -x
+openssl x509 -in server-cert.pem -out server-cert.der -outform der
+openssl rsa -in server-key.pem -out server-key.der -outform der
+openssl rsa -in server-key.pem -out server-key.enc -passout pass:bluebell
+openssl rsa -in client-key.pem -out client-key.enc -passout pass:opossum
+openssl pkcs12 -export -in server-cert.pem -inkey server-key.pem -out server.p12 -passout pass:
+openssl pkcs12 -export -in server-cert.pem -inkey server-key.pem -out server_enc.p12 -passout pass:bluebell
+CMD
diff --git a/lib/PublicInbox/DS.pm b/lib/PublicInbox/DS.pm
index 1a1ef7d3..044b991c 100644
--- a/lib/PublicInbox/DS.pm
+++ b/lib/PublicInbox/DS.pm
@@ -465,7 +465,11 @@ next_buf:
             }
         } else { #($ref eq 'CODE') {
             shift @$wbuf;
+            my $before = scalar(@$wbuf);
             $bref->($self);
+
+            # bref may be enqueueing more CODE to call (see accept_tls_step)
+            return 0 if (scalar(@$wbuf) > $before);
         }
     } # while @$wbuf
 
@@ -479,7 +483,14 @@ sub do_read ($$$$) {
     return ($r == 0 ? $self->close : $r) if defined $r;
     # common for clients to break connections without warning,
     # would be too noisy to log here:
-    $! == EAGAIN ? $self->watch_in1 : $self->close;
+    if (ref($self) eq 'IO::Socket::SSL') {
+        my $ev = PublicInbox::TLS::epollbit() or return $self->close;
+        watch($self, $ev | EPOLLONESHOT);
+    } elsif ($! == EAGAIN) {
+        watch($self, EPOLLIN | EPOLLONESHOT);
+    } else {
+        $self->close;
+    }
 }
 
 # drop the socket if we hit unrecoverable errors on our system which
@@ -566,7 +577,7 @@ sub msg_more ($$) {
     my $self = $_[0];
     my $sock = $self->{sock} or return 1;
 
-    if (MSG_MORE && !$self->{wbuf}) {
+    if (MSG_MORE && !$self->{wbuf} && ref($sock) ne 'IO::Socket::SSL') {
         my $n = send($sock, $_[1], MSG_MORE);
         if (defined $n) {
             my $nlen = bytes::length($_[1]) - $n;
@@ -597,6 +608,19 @@ sub watch ($$) {
 
 sub watch_in1 ($) { watch($_[0], EPOLLIN | EPOLLONESHOT) }
 
+# return true if complete, false if incomplete (or failure)
+sub accept_tls_step ($) {
+    my ($self) = @_;
+    my $sock = $self->{sock} or return;
+    return 1 if $sock->accept_SSL;
+    return $self->close if $! != EAGAIN;
+    if (my $ev = PublicInbox::TLS::epollbit()) {
+        unshift @{$self->{wbuf} ||= []}, \&accept_tls_step;
+        return watch($self, $ev | EPOLLONESHOT);
+    }
+    drop($self, 'BUG? EAGAIN but '.PublicInbox::TLS::err());
+}
+
 package PublicInbox::DS::Timer;
 # [$abs_float_firetime, $coderef];
 sub cancel {
diff --git a/lib/PublicInbox/Daemon.pm b/lib/PublicInbox/Daemon.pm
index b8d6b572..24c13ad2 100644
--- a/lib/PublicInbox/Daemon.pm
+++ b/lib/PublicInbox/Daemon.pm
@@ -22,12 +22,48 @@ my (@cfg_listen, $stdout, $stderr, $group, $user, $pid_file, $daemonize);
 my $worker_processes = 1;
 my @listeners;
 my %pids;
-my %listener_names;
+my %listener_names; # sockname => IO::Handle
+my %tls_opt; # scheme://sockname => args for IO::Socket::SSL->start_SSL
 my $reexec_pid;
 my $cleanup;
 my ($uid, $gid);
+my ($default_cert, $default_key);
 END { $cleanup->() if $cleanup };
 
+sub tls_listen ($$$) {
+        my ($scheme, $sockname, $opt_str) = @_;
+        # opt_str: opt1=val1,opt2=val2 (opt may repeat for multi-value)
+        require PublicInbox::TLS;
+        my $o = {};
+        # allow ',' as delimiter since '&' is shell-unfriendly
+        foreach (split(/[,&]/, $opt_str)) {
+                my ($k, $v) = split(/=/, $_, 2);
+                push @{$o->{$k} ||= []}, $v;
+        }
+
+        # key may be a part of cert.  At least
+        # p5-io-socket-ssl/example/ssl_server.pl has this fallback:
+        $o->{cert} //= [ $default_cert ];
+        $o->{key} //= defined($default_key) ? [ $default_key ] : $o->{cert};
+        my %ctx_opt = (SSL_server => 1);
+        # parse out hostname:/path/to/ mappings:
+        foreach my $k (qw(cert key)) {
+                my $x = $ctx_opt{'SSL_'.$k.'_file'} = {};
+                foreach my $path (@{$o->{$k}}) {
+                        my $host = '';
+                        $path =~ s/\A([^:]+):// and $host = $1;
+                        $x->{$host} = $path;
+                }
+        }
+        my $ctx = IO::Socket::SSL::SSL_Context->new(%ctx_opt) or
+                die 'SSL_Context->new: '.PublicInbox::TLS::err();
+        $tls_opt{"$scheme://$sockname"} = {
+                SSL_server => 1,
+                SSL_startHandshake => 0,
+                SSL_reuse_ctx => $ctx
+        };
+}
+
 sub daemon_prepare ($) {
         my ($default_listen) = @_;
         @CMD = ($0, @ARGV);
@@ -42,6 +78,8 @@ sub daemon_prepare ($) {
                 'u|user=s' => \$user,
                 'g|group=s' => \$group,
                 'D|daemonize' => \$daemonize,
+                'cert=s' => \$default_cert,
+                'key=s' => \$default_key,
         );
         GetOptions(%opts) or die "bad command-line args\n";
 
@@ -55,6 +93,18 @@ sub daemon_prepare ($) {
         push @cfg_listen, $default_listen unless (@listeners || @cfg_listen);
 
         foreach my $l (@cfg_listen) {
+                my $orig = $l;
+                my $scheme = '';
+                $l =~ s!\A([^:]+)://!! and $scheme = $1;
+                if ($l =~ s!/?\?(.+)\z!!) {
+                        tls_listen($scheme, $l, $1);
+                } elsif (defined($default_cert)) {
+                        tls_listen($scheme, $l, '');
+                } elsif ($scheme =~ /\A(?:nntps|https)\z/) {
+                        die "$orig specified w/o cert=\n";
+                }
+                # TODO: use scheme to load either NNTP.pm or HTTP.pm
+
                 next if $listener_names{$l}; # already inherited
                 my (%o, $sock_pkg);
                 if (index($l, '/') == 0) {
@@ -461,9 +511,26 @@ sub master_loop {
         exit # never gets here, just for documentation
 }
 
-sub daemon_loop ($$) {
-        my ($refresh, $post_accept) = @_;
+sub tls_start_cb ($$) {
+        my ($opt, $orig_post_accept) = @_;
+        sub {
+                my ($io, $addr, $srv) = @_;
+                my $ssl = IO::Socket::SSL->start_SSL($io, %$opt);
+                $orig_post_accept->($ssl, $addr, $srv);
+        }
+}
+
+sub daemon_loop ($$$) {
+        my ($refresh, $post_accept, $nntpd) = @_;
         PublicInbox::EvCleanup::enable(); # early for $refresh
+        my %post_accept;
+        while (my ($k, $v) = each %tls_opt) {
+                if ($k =~ s!\A(?:nntps|https)://!!) {
+                        $post_accept{$k} = tls_start_cb($v, $post_accept);
+                } elsif ($nntpd) { # STARTTLS, $k eq '' is OK
+                        $nntpd->{accept_tls} = $v;
+                }
+        }
         my $parent_pipe;
         if ($worker_processes > 0) {
                 $refresh->(); # preload by default
@@ -484,18 +551,19 @@ sub daemon_loop ($$) {
         $SIG{$_} = 'IGNORE' for qw(USR2 TTIN TTOU WINCH);
         # this calls epoll_create:
         @listeners = map {
-                PublicInbox::Listener->new($_, $post_accept)
+                PublicInbox::Listener->new($_,
+                                $post_accept{sockname($_)} || $post_accept)
         } @listeners;
         PublicInbox::DS->EventLoop;
         $parent_pipe = undef;
 }
 
 
-sub run ($$$) {
-        my ($default, $refresh, $post_accept) = @_;
+sub run ($$$;$) {
+        my ($default, $refresh, $post_accept, $nntpd) = @_;
         daemon_prepare($default);
         daemonize();
-        daemon_loop($refresh, $post_accept);
+        daemon_loop($refresh, $post_accept, $nntpd);
 }
 
 sub do_chown ($) {
diff --git a/lib/PublicInbox/NNTP.pm b/lib/PublicInbox/NNTP.pm
index a18641d3..659e44d5 100644
--- a/lib/PublicInbox/NNTP.pm
+++ b/lib/PublicInbox/NNTP.pm
@@ -1,4 +1,4 @@
-# Copyright (C) 2015-2018 all contributors <meta@public-inbox.org>
+# Copyright (C) 2015-2019 all contributors <meta@public-inbox.org>
 # License: AGPL-3.0+ <https://www.gnu.org/licenses/agpl-3.0.txt>
 #
 # Each instance of this represents a NNTP client socket
@@ -98,11 +98,19 @@ sub expire_old () {
 sub new ($$$) {
         my ($class, $sock, $nntpd) = @_;
         my $self = fields::new($class);
-        $self->SUPER::new($sock, EPOLLOUT | EPOLLONESHOT);
+        my $ev = EPOLLOUT | EPOLLONESHOT;
+        my $wbuf = [];
+        if (ref($sock) eq 'IO::Socket::SSL' && !$sock->accept_SSL) {
+                $ev = PublicInbox::TLS::epollbit() or return $sock->close;
+                $ev |= EPOLLONESHOT;
+                $wbuf->[0] = \&PublicInbox::DS::accept_tls_step;
+        }
+        $self->SUPER::new($sock, $ev);
         $self->{nntpd} = $nntpd;
         my $greet = "201 $nntpd->{servername} ready - post via email\r\n";
         open my $fh, '<:scalar',  \$greet or die "open :scalar: $!";
-        $self->{wbuf} = [ $fh ];
+        push @$wbuf, $fh;
+        $self->{wbuf} = $wbuf;
         $self->{rbuf} = '';
         update_idle_time($self);
         $expt ||= PublicInbox::EvCleanup::later(*expire_old);
@@ -900,6 +908,19 @@ sub cmd_xover ($;$) {
         });
 }
 
+sub cmd_starttls ($) {
+        my ($self) = @_;
+        my $sock = $self->{sock} or return;
+        # RFC 4642 2.2.1
+        (ref($sock) eq 'IO::Socket::SSL') and return '502 Command unavailable';
+        my $opt = $self->{nntpd}->{accept_tls} or
+                return '580 can not initiate TLS negotiation';
+        res($self, '382 Continue with TLS negotiation');
+        $self->{sock} = IO::Socket::SSL->start_SSL($sock, %$opt);
+        requeue($self) if PublicInbox::DS::accept_tls_step($self);
+        undef;
+}
+
 sub cmd_xpath ($$) {
         my ($self, $mid) = @_;
         return r501 unless $mid =~ /\A<(.+)>\z/;
diff --git a/lib/PublicInbox/NNTPD.pm b/lib/PublicInbox/NNTPD.pm
index 32848d7c..6d9ffd5f 100644
--- a/lib/PublicInbox/NNTPD.pm
+++ b/lib/PublicInbox/NNTPD.pm
@@ -25,6 +25,7 @@ sub new {
                 out => \*STDOUT,
                 grouplist => [],
                 servername => $name,
+                # accept_tls => { SSL_server => 1, ..., SSL_reuse_ctx => ... }
         }, $class;
 }
 
diff --git a/lib/PublicInbox/TLS.pm b/lib/PublicInbox/TLS.pm
new file mode 100644
index 00000000..576c11d7
--- /dev/null
+++ b/lib/PublicInbox/TLS.pm
@@ -0,0 +1,24 @@
+# Copyright (C) 2019 all contributors <meta@public-inbox.org>
+# License: AGPL-3.0+ <https://www.gnu.org/licenses/agpl-3.0.txt>
+
+# IO::Socket::SSL support code
+package PublicInbox::TLS;
+use strict;
+use IO::Socket::SSL;
+require Carp;
+use Errno qw(EAGAIN);
+use PublicInbox::Syscall qw(EPOLLIN EPOLLOUT);
+
+sub err () { $SSL_ERROR }
+
+# returns the EPOLL event bit which matches the existing SSL error
+sub epollbit () {
+        if ($! == EAGAIN) {
+                return EPOLLIN if $SSL_ERROR == SSL_WANT_READ;
+                return EPOLLOUT if $SSL_ERROR == SSL_WANT_WRITE;
+                die "unexpected SSL error: $SSL_ERROR";
+        }
+        0;
+}
+
+1;
diff --git a/script/public-inbox-nntpd b/script/public-inbox-nntpd
index 484ce8d6..55bf330e 100755
--- a/script/public-inbox-nntpd
+++ b/script/public-inbox-nntpd
@@ -11,4 +11,5 @@ require PublicInbox::NNTPD;
 my $nntpd = PublicInbox::NNTPD->new;
 PublicInbox::Daemon::run('0.0.0.0:119',
         sub { $nntpd->refresh_groups }, # refresh
-        sub ($$$) { PublicInbox::NNTP->new($_[0], $nntpd) }); # post_accept
+        sub ($$$) { PublicInbox::NNTP->new($_[0], $nntpd) }, # post_accept
+        $nntpd);
diff --git a/t/nntpd-tls.t b/t/nntpd-tls.t
new file mode 100644
index 00000000..53890ff2
--- /dev/null
+++ b/t/nntpd-tls.t
@@ -0,0 +1,156 @@
+# Copyright (C) 2019 all contributors <meta@public-inbox.org>
+# License: AGPL-3.0+ <https://www.gnu.org/licenses/agpl-3.0.txt>
+use strict;
+use warnings;
+use Test::More;
+use File::Temp qw(tempdir);
+use Socket qw(SOCK_STREAM);
+foreach my $mod (qw(DBD::SQLite IO::Socket::SSL Net::NNTP)) {
+        eval "require $mod";
+        plan skip_all => "$mod missing for $0" if $@;
+}
+my $cert = 'certs/server-cert.pem';
+my $key = 'certs/server-key.pem';
+unless (-r $key && -r $cert) {
+        plan skip_all =>
+                "certs/ missing for $0, run ./create-certs.perl in certs/";
+}
+
+use_ok 'PublicInbox::TLS';
+use_ok 'IO::Socket::SSL';
+require './t/common.perl';
+require PublicInbox::InboxWritable;
+require PublicInbox::MIME;
+require PublicInbox::SearchIdx;
+my $version = 2; # v2 needs newer git
+require_git('2.6') if $version >= 2;
+my $tmpdir = tempdir('pi-nntpd-tls-XXXXXX', TMPDIR => 1, CLEANUP => 1);
+my $err = "$tmpdir/stderr.log";
+my $out = "$tmpdir/stdout.log";
+my $mainrepo = "$tmpdir";
+my $pi_config = "$tmpdir/pi_config";
+my $group = 'test-nntpd-tls';
+my $addr = $group . '@example.com';
+my $nntpd = 'blib/script/public-inbox-nntpd';
+my %opts = (
+        LocalAddr => '127.0.0.1',
+        ReuseAddr => 1,
+        Proto => 'tcp',
+        Type => SOCK_STREAM,
+        Listen => 1024,
+);
+my $starttls = IO::Socket::INET->new(%opts);
+my $nntps = IO::Socket::INET->new(%opts);
+my ($pid, $tail_pid);
+END {
+        foreach ($pid, $tail_pid) {
+                kill 'TERM', $_ if defined $_;
+        }
+};
+
+my $ibx = PublicInbox::Inbox->new({
+        mainrepo => $mainrepo,
+        name => 'nntpd-tls',
+        version => $version,
+        -primary_address => $addr,
+        indexlevel => 'basic',
+});
+$ibx = PublicInbox::InboxWritable->new($ibx, {nproc=>1});
+$ibx->init_inbox(0);
+{
+        open my $fh, '>', $pi_config or die "open: $!\n";
+        print $fh <<EOF
+[publicinbox "nntpd-tls"]
+        mainrepo = $mainrepo
+        address = $addr
+        indexlevel = basic
+        newsgroup = $group
+EOF
+        ;
+        close $fh or die "close: $!\n";
+}
+
+{
+        my $im = $ibx->importer(0);
+        my $mime = PublicInbox::MIME->new(do {
+                open my $fh, '<', 't/data/0001.patch' or die;
+                local $/;
+                <$fh>
+        });
+        ok($im->add($mime), 'message added');
+        $im->done;
+        if ($version == 1) {
+                my $s = PublicInbox::SearchIdx->new($ibx, 1);
+                $s->index_sync;
+        }
+}
+
+my $nntps_addr = $nntps->sockhost . ':' . $nntps->sockport;
+my $starttls_addr = $starttls->sockhost . ':' . $starttls->sockport;
+my $env = { PI_CONFIG => $pi_config };
+
+for my $args (
+        [ "--cert=$cert", "--key=$key",
+                "-lnntps://$nntps_addr",
+                "-lnntp://$starttls_addr" ],
+) {
+        for ($out, $err) {
+                open my $fh, '>', $_ or die "truncate: $!";
+        }
+        if (my $tail_cmd = $ENV{TAIL}) { # don't assume GNU tail
+                $tail_pid = fork;
+                if (defined $tail_pid && $tail_pid == 0) {
+                        exec(split(' ', $tail_cmd), $out, $err);
+                }
+        }
+        my $cmd = [ $nntpd, '-W0', @$args, "--stdout=$out", "--stderr=$err" ];
+        $pid = spawn_listener($env, $cmd, [ $starttls, $nntps ]);
+        my %o = (
+                SSL_hostname => 'server.local',
+                SSL_verifycn_name => 'server.local',
+                SSL => 1,
+                SSL_verify_mode => SSL_VERIFY_PEER(),
+                SSL_ca_file => 'certs/test-ca.pem',
+        );
+        my $expect = { $group => [qw(1 1 n)] };
+
+        # NNTPS
+        my $c = Net::NNTP->new($nntps_addr, %o);
+        my $list = $c->list;
+        is_deeply($list, $expect, 'NNTPS LIST works');
+
+        # STARTTLS
+        delete $o{SSL};
+        $c = Net::NNTP->new($starttls_addr, %o);
+        $list = $c->list;
+        is_deeply($list, $expect, 'plain LIST works');
+        ok($c->starttls, 'STARTTLS succeeds');
+        is($c->code, 382, 'got 382 for STARTTLS');
+        $list = $c->list;
+        is_deeply($list, $expect, 'LIST works after STARTTLS');
+
+        # Net::NNTP won't let us do dumb things, but we need to test
+        # dumb things, so use Net::Cmd directly:
+        my $n = $c->command('STARTTLS')->response();
+        is($n, Net::Cmd::CMD_ERROR(), 'error attempting STARTTLS again');
+        is($c->code, 502, '502 according to RFC 4642 sec#2.2.1');
+
+        $c = undef;
+        kill('TERM', $pid);
+        is($pid, waitpid($pid, 0), 'nntpd exited successfully');
+        is($?, 0, 'no error in exited process');
+        $pid = undef;
+        my $eout = eval {
+                open my $fh, '<', $err or die "open $err failed: $!";
+                local $/;
+                <$fh>;
+        };
+        unlike($eout, qr/wide/i, 'no Wide character warnings');
+        if (defined $tail_pid) {
+                kill 'TERM', $tail_pid;
+                waitpid($tail_pid, 0);
+                $tail_pid = undef;
+        }
+}
+done_testing();
+1;
diff --git a/t/nntpd.t b/t/nntpd.t
index c37880bf..6cba2be4 100644
--- a/t/nntpd.t
+++ b/t/nntpd.t
@@ -106,6 +106,8 @@ EOF
         is_deeply($list, { $group => [ qw(1 1 n) ] }, 'LIST works');
         is_deeply([$n->group($group)], [ qw(0 1 1), $group ], 'GROUP works');
         is_deeply($n->listgroup($group), [1], 'listgroup OK');
+        ok(!$n->starttls, 'STARTTLS fails when unconfigured');
+        is($n->code, 580, 'got 580 code on server w/o TLS');
 
         %opts = (
                 PeerAddr => $host_port,