Add a test for TLSv1.3 cookies

We just check that if we insert a cookie into an HRR it gets echoed back
in the subsequent ClientHello.
Reviewed-by: NRich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/2839)

test/recipes/70-test_tls13cookie.t

+#! /usr/bin/env perl
+# Copyright 2017 The OpenSSL Project Authors. All Rights Reserved.
+#
+# Licensed under the OpenSSL license (the "License").  You may not use
+# this file except in compliance with the License.  You can obtain a copy
+# in the file LICENSE in the source distribution or at
+# https://www.openssl.org/source/license.html
+
+use strict;
+use OpenSSL::Test qw/:DEFAULT cmdstr srctop_file bldtop_dir/;
+use OpenSSL::Test::Utils;
+use TLSProxy::Proxy;
+
+my $test_name = "test_tls13cookie";
+setup($test_name);
+
+plan skip_all => "TLSProxy isn't usable on $^O"
+    if $^O =~ /^(VMS|MSWin32)$/;
+
+plan skip_all => "$test_name needs the dynamic engine feature enabled"
+    if disabled("engine") || disabled("dynamic-engine");
+
+plan skip_all => "$test_name needs the sock feature enabled"
+    if disabled("sock");
+
+plan skip_all => "$test_name needs TLS1.3 enabled"
+    if disabled("tls1_3");
+
+$ENV{OPENSSL_ia32cap} = '~0x200000200000000';
+
+my $proxy = TLSProxy::Proxy->new(
+    undef,
+    cmdstr(app(["openssl"]), display => 1),
+    srctop_file("apps", "server.pem"),
+    (!$ENV{HARNESS_ACTIVE} || $ENV{HARNESS_VERBOSE})
+);
+
+my $cookieseen = 0;
+
+#Test 1: Inserting a cookie into an HRR should see it echoed in the ClientHello
+$proxy->filter(\&cookie_filter);
+$proxy->serverflags("-curves P-256");
+$proxy->start() or plan skip_all => "Unable to start up Proxy for tests";
+plan tests => 1;
+ok(TLSProxy::Message->success() && $cookieseen == 1, "Cookie seen");
+
+sub cookie_filter
+{
+    my $proxy = shift;
+
+    # We're only interested in the HRR and subsequent ClientHello
+    if ($proxy->flight != 1 && $proxy->flight != 2) {
+        return;
+    }
+
+    my $ext = pack "C8",
+        0x00, 0x06, #Cookie Length
+        0x00, 0x01, #Dummy cookie data (6 bytes)
+        0x02, 0x03,
+        0x04, 0x05;
+
+    foreach my $message (@{$proxy->message_list}) {
+        if ($message->mt == TLSProxy::Message::MT_HELLO_RETRY_REQUEST) {
+
+            $message->set_extension(TLSProxy::Message::EXT_COOKIE, $ext);
+            $message->repack();
+        } elsif ($message->mt == TLSProxy::Message::MT_CLIENT_HELLO
+                    && ${$message->records}[0]->flight == 2) {
+            #cmp can behave differently dependent on locale
+            no locale;
+            my $cookie =
+                $message->extension_data->{TLSProxy::Message::EXT_COOKIE};
+
+            return if !defined($cookie);
+
+            return if ($cookie cmp $ext) != 0;
+
+            $cookieseen = 1;
+        }
+    }
+}

util/TLSProxy/Message.pm

@@ -78,6 +78,7 @@ use constant {
     EXT_KEY_SHARE => 40,
     EXT_PSK => 41,
     EXT_SUPPORTED_VERSIONS => 43,
+    EXT_COOKIE => 44,
     EXT_PSK_KEX_MODES => 45,
     EXT_RENEGOTIATE => 65281,
     EXT_NPN => 13172,