Repair downgrade tests

A number of these tests were failing for the wrong reasons. The intention is to verify
that the client sends an illegal parameter alert when an unexpected downgrade signal
is received. Instead, a number of tests failed because TLS1.1 was not available. The
tests are adapted to explicitly check for an illegal parameter alert from the client.

Client and server flags are updated to enable TLS1.1 where required and a few tests
requiring TLS1.1 were moved to be disabled when TLS1.1 is not available.

Reviewed-by: Matt Caswell <matt@openssl.org>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/27518)

diff --git a/test/recipes/70-test_tls13downgrade.t b/test/recipes/70-test_tls13downgrade.t
index 999a79e62a84c6705064b660bcb0fbfb01b180fa..9a5925c8e60faf95c5878b5acf9b42eaa1286262 100644 (file)
--- a/test/recipes/70-test_tls13downgrade.t
+++ b/test/recipes/70-test_tls13downgrade.t
@@ -24,9 +24,8 @@ plan skip_all => "$test_name needs the sock feature enabled"
     if disabled("sock");
 
 plan skip_all => "$test_name needs TLS1.3 and TLS1.2 enabled"
-    if disabled("tls1_3")
-       || (disabled("ec") && disabled("dh"))
-       || disabled("tls1_2");
+    if disabled("tls1_3") || disabled("tls1_2")
+        || (disabled("ec") && disabled("dh"));
 
 my $proxy = TLSProxy::Proxy->new(
     undef,
@@ -46,51 +45,72 @@ $proxy->filter(\&downgrade_filter);
 my $testtype = DOWNGRADE_TO_TLS_1_2;
 $proxy->start() or plan skip_all => "Unable to start up Proxy for tests";
 plan tests => 6;
-ok(TLSProxy::Message->fail(), "Downgrade TLSv1.3 to TLSv1.2");
+ok(is_illegal_parameter_client_alert(), "Downgrade TLSv1.3 to TLSv1.2");
 
-#Test 2: Downgrade from TLSv1.3 to TLSv1.1
-$proxy->clear();
-$testtype = DOWNGRADE_TO_TLS_1_1;
-$proxy->start();
-ok(TLSProxy::Message->fail(), "Downgrade TLSv1.3 to TLSv1.1");
-
-#Test 3: Downgrade from TLSv1.2 to TLSv1.1
-$proxy->clear();
-$proxy->clientflags("-no_tls1_3");
-$proxy->serverflags("-no_tls1_3");
-$proxy->start();
-ok(TLSProxy::Message->fail(), "Downgrade TLSv1.2 to TLSv1.1");
-
-#Test 4: Client falls back from TLSv1.3 (server does not support the fallback
+#Test 2: Client falls back from TLSv1.3 (server does not support the fallback
 #        SCSV)
 $proxy->clear();
 $testtype = FALLBACK_FROM_TLS_1_3;
 $proxy->clientflags("-fallback_scsv -no_tls1_3");
 $proxy->start();
-my $alert = TLSProxy::Message->alert();
-ok(TLSProxy::Message->fail()
-   && !$alert->server()
-   && $alert->description() == TLSProxy::Message::AL_DESC_ILLEGAL_PARAMETER,
-   "Fallback from TLSv1.3");
+ok(is_illegal_parameter_client_alert(), "Fallback from TLSv1.3");
 
 SKIP: {
-    skip "TLSv1.1 disabled", 2 if disabled("tls1_1");
+    skip "TLSv1.1 disabled", 4 if disabled("tls1_1");
+
+    my $client_flags = "-min_protocol TLSv1.1 -cipher DEFAULT:\@SECLEVEL=0";
+    my $server_flags = "-min_protocol TLSv1.1";
+    my $ciphers = "AES128-SHA:\@SECLEVEL=0";
+
+    #Test 3: Downgrade from TLSv1.3 to TLSv1.1
+    $proxy->clear();
+    $testtype = DOWNGRADE_TO_TLS_1_1;
+    $proxy->clientflags($client_flags);
+    $proxy->serverflags($server_flags);
+    $proxy->ciphers($ciphers);
+    $proxy->start();
+    ok(is_illegal_parameter_client_alert(), "Downgrade TLSv1.3 to TLSv1.1");
+
+    #Test 4: Downgrade from TLSv1.2 to TLSv1.1
+    $proxy->clear();
+    $testtype = DOWNGRADE_TO_TLS_1_1;
+    $proxy->clientflags($client_flags." -max_protocol TLSv1.2");
+    $proxy->serverflags($server_flags." -max_protocol TLSv1.2");
+    $proxy->ciphers($ciphers);
+    $proxy->start();
+    ok(is_illegal_parameter_client_alert(), "Downgrade TLSv1.2 to TLSv1.1");
+
     #Test 5: A client side protocol "hole" should not be detected as a downgrade
     $proxy->clear();
     $proxy->filter(undef);
-    $proxy->clientflags("-no_tls1_2");
-    $proxy->ciphers("AES128-SHA:\@SECLEVEL=0");
+    $proxy->clientflags($client_flags." -no_tls1_2");
+    $proxy->serverflags($server_flags);
+    $proxy->ciphers($ciphers);
     $proxy->start();
     ok(TLSProxy::Message->success(), "TLSv1.2 client-side protocol hole");
 
     #Test 6: A server side protocol "hole" should not be detected as a downgrade
     $proxy->clear();
     $proxy->filter(undef);
-    $proxy->serverflags("-no_tls1_2");
+    $proxy->clientflags($client_flags);
+    $proxy->serverflags($server_flags." -no_tls1_2");
+    $proxy->ciphers($ciphers);
     $proxy->start();
     ok(TLSProxy::Message->success(), "TLSv1.2 server-side protocol hole");
 }
 
+# Validate that the exchange fails with an illegal parameter alert from
+#  the client
+sub is_illegal_parameter_client_alert
+{
+    return 0 unless TLSProxy::Message->fail();
+    my $alert = TLSProxy::Message->alert();
+    return 1 if !$alert->server()
+                && $alert->description()
+                   == TLSProxy::Message::AL_DESC_ILLEGAL_PARAMETER;
+    return 0;
+}
+
 sub downgrade_filter
 {
     my $proxy = shift;