Improve priority string and fallback rules for the post-POODLE world (#1177964)

This commit is contained in:
Dan Winship 2015-03-06 13:33:51 -05:00
parent 6b569dbdbd
commit 03a3d354a0
3 changed files with 307 additions and 1 deletions

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@ -0,0 +1,220 @@
From 1b8db6c27f2f3909b55fc2902d2fd0431b066058 Mon Sep 17 00:00:00 2001
From: Dan Winship <danw@gnome.org>
Date: Sun, 26 Oct 2014 12:25:15 -0400
Subject: [PATCH 1/2] gnutls: loosen the semantics of "use-ssl3"
If SSL 3.0 is disabled, then make "use-ssl3" mean "use the lowest
available TLS version" instead, so that, eg, TLS 1.2 -> TLS 1.0
fallback is still possible.
https://bugzilla.gnome.org/show_bug.cgi?id=738633
---
tls/gnutls/gtlsconnection-gnutls.c | 55 +++++++++++++++++-------
tls/tests/connection.c | 88 ++++++++++++++++++++++++++++++++++++++
2 files changed, 127 insertions(+), 16 deletions(-)
diff --git a/tls/gnutls/gtlsconnection-gnutls.c b/tls/gnutls/gtlsconnection-gnutls.c
index 7e63412..444ca36 100644
--- a/tls/gnutls/gtlsconnection-gnutls.c
+++ b/tls/gnutls/gtlsconnection-gnutls.c
@@ -194,15 +194,16 @@ g_tls_connection_gnutls_init (GTlsConnectionGnutls *gnutls)
g_mutex_init (&gnutls->priv->op_mutex);
}
-/* First field is "ssl3 only", second is "allow unsafe rehandshaking" */
+/* First field is "fallback", second is "allow unsafe rehandshaking" */
static gnutls_priority_t priorities[2][2];
static void
g_tls_connection_gnutls_init_priorities (void)
{
const gchar *base_priority;
- gchar *ssl3_priority, *unsafe_rehandshake_priority, *ssl3_unsafe_rehandshake_priority;
- int ret;
+ gchar *fallback_priority, *unsafe_rehandshake_priority, *fallback_unsafe_rehandshake_priority;
+ const guint *protos;
+ int ret, i, nprotos, fallback_proto;
base_priority = g_getenv ("G_TLS_GNUTLS_PRIORITY");
if (!base_priority)
@@ -215,31 +216,53 @@ g_tls_connection_gnutls_init_priorities (void)
gnutls_priority_init (&priorities[FALSE][FALSE], base_priority, NULL);
}
- ssl3_priority = g_strdup_printf ("%s:!VERS-TLS1.2:!VERS-TLS1.1:!VERS-TLS1.0", base_priority);
unsafe_rehandshake_priority = g_strdup_printf ("%s:%%UNSAFE_RENEGOTIATION", base_priority);
- ssl3_unsafe_rehandshake_priority = g_strdup_printf ("%s:!VERS-TLS1.2:!VERS-TLS1.1:!VERS-TLS1.0:%%UNSAFE_RENEGOTIATION", base_priority);
-
- gnutls_priority_init (&priorities[TRUE][FALSE], ssl3_priority, NULL);
- gnutls_priority_init (&priorities[FALSE][TRUE], unsafe_rehandshake_priority, NULL);
- gnutls_priority_init (&priorities[TRUE][TRUE], ssl3_unsafe_rehandshake_priority, NULL);
-
- g_free (ssl3_priority);
+ ret = gnutls_priority_init (&priorities[FALSE][TRUE], unsafe_rehandshake_priority, NULL);
+ g_warn_if_fail (ret == 0);
g_free (unsafe_rehandshake_priority);
- g_free (ssl3_unsafe_rehandshake_priority);
+
+ /* Figure out the lowest SSl/TLS version supported by base_priority */
+ nprotos = gnutls_priority_protocol_list (priorities[FALSE][FALSE], &protos);
+ fallback_proto = G_MAXUINT;
+ for (i = 0; i < nprotos; i++)
+ {
+ if (protos[i] < fallback_proto)
+ fallback_proto = protos[i];
+ }
+ if (fallback_proto == G_MAXUINT)
+ {
+ g_warning ("All GNUTLS protocol versions disabled?");
+ fallback_priority = g_strdup (base_priority);
+ }
+ else
+ {
+ fallback_priority = g_strdup_printf ("%s:!VERS-TLS-ALL:+VERS-%s",
+ base_priority,
+ gnutls_protocol_get_name (fallback_proto));
+ }
+ fallback_unsafe_rehandshake_priority = g_strdup_printf ("%s:%%UNSAFE_RENEGOTIATION",
+ fallback_priority);
+
+ ret = gnutls_priority_init (&priorities[TRUE][FALSE], fallback_priority, NULL);
+ g_warn_if_fail (ret == 0);
+ ret = gnutls_priority_init (&priorities[TRUE][TRUE], fallback_unsafe_rehandshake_priority, NULL);
+ g_warn_if_fail (ret == 0);
+ g_free (fallback_priority);
+ g_free (fallback_unsafe_rehandshake_priority);
}
static void
g_tls_connection_gnutls_set_handshake_priority (GTlsConnectionGnutls *gnutls)
{
- gboolean use_ssl3, unsafe_rehandshake;
+ gboolean fallback, unsafe_rehandshake;
if (G_IS_TLS_CLIENT_CONNECTION (gnutls))
- use_ssl3 = g_tls_client_connection_get_use_ssl3 (G_TLS_CLIENT_CONNECTION (gnutls));
+ fallback = g_tls_client_connection_get_use_ssl3 (G_TLS_CLIENT_CONNECTION (gnutls));
else
- use_ssl3 = FALSE;
+ fallback = FALSE;
unsafe_rehandshake = (gnutls->priv->rehandshake_mode == G_TLS_REHANDSHAKE_UNSAFELY);
gnutls_priority_set (gnutls->priv->session,
- priorities[use_ssl3][unsafe_rehandshake]);
+ priorities[fallback][unsafe_rehandshake]);
}
static gboolean
diff --git a/tls/tests/connection.c b/tls/tests/connection.c
index 0df8bb1..0e7b706 100644
--- a/tls/tests/connection.c
+++ b/tls/tests/connection.c
@@ -1377,11 +1377,90 @@ test_async_implicit_handshake (TestConnection *test, gconstpointer data)
test->client_connection = NULL;
}
+static void
+quit_on_handshake_complete (GObject *object,
+ GAsyncResult *result,
+ gpointer user_data)
+{
+ TestConnection *test = user_data;
+ GError *error = NULL;
+
+ g_tls_connection_handshake_finish (G_TLS_CONNECTION (object), result, &error);
+ g_assert_no_error (error);
+
+ g_main_loop_quit (test->loop);
+ return;
+}
+
+#define PRIORITY_SSL_FALLBACK "NORMAL:+VERS-SSL3.0"
+#define PRIORITY_TLS_FALLBACK "NORMAL:+VERS-TLS-ALL:-VERS-SSL3.0"
+
+static void
+test_fallback (gconstpointer data)
+{
+ const char *priority_string = (const char *) data;
+ char *test_name;
+
+ test_name = g_strdup_printf ("/tls/connection/fallback/subprocess/%s", priority_string);
+ g_test_trap_subprocess (test_name, 0, 0);
+ g_test_trap_assert_passed ();
+ g_free (test_name);
+}
+
+static void
+test_fallback_subprocess (TestConnection *test,
+ gconstpointer data)
+{
+ GIOStream *connection;
+ GTlsConnection *tlsconn;
+ GError *error = NULL;
+
+ connection = start_echo_server_and_connect_to_it (test);
+ test->client_connection = g_tls_client_connection_new (connection, NULL, &error);
+ g_assert_no_error (error);
+ tlsconn = G_TLS_CONNECTION (test->client_connection);
+ g_object_unref (connection);
+
+ g_tls_client_connection_set_validation_flags (G_TLS_CLIENT_CONNECTION (test->client_connection),
+ 0);
+ g_tls_client_connection_set_use_ssl3 (G_TLS_CLIENT_CONNECTION (test->client_connection),
+ TRUE);
+ g_tls_connection_handshake_async (tlsconn, G_PRIORITY_DEFAULT, NULL,
+ quit_on_handshake_complete, test);
+ g_main_loop_run (test->loop);
+
+ /* In 2.42 we don't have the API to test that the correct version was negotiated,
+ * so we merely test that the connection succeeded at all.
+ */
+
+ g_io_stream_close (test->client_connection, NULL, &error);
+ g_assert_no_error (error);
+}
+
int
main (int argc,
char *argv[])
{
int ret;
+ int i;
+
+ /* Check if this is a subprocess, and set G_TLS_GNUTLS_PRIORITY
+ * appropriately if so.
+ */
+ for (i = 1; i < argc - 1; i++)
+ {
+ if (!strcmp (argv[i], "-p"))
+ {
+ const char *priority = argv[i + 1];
+
+ priority = strrchr (priority, '/');
+ if (priority++ &&
+ (g_str_has_prefix (priority, "NORMAL:") ||
+ g_str_has_prefix (priority, "NONE:")))
+ g_setenv ("G_TLS_GNUTLS_PRIORITY", priority, TRUE);
+ break;
+ }
+ }
g_test_init (&argc, &argv, NULL);
g_test_bug_base ("http://bugzilla.gnome.org/");
@@ -1431,6 +1510,15 @@ main (int argc,
g_test_add ("/tls/connection/async-implicit-handshake", TestConnection, NULL,
setup_connection, test_async_implicit_handshake, teardown_connection);
+ g_test_add_data_func ("/tls/connection/fallback/SSL", PRIORITY_SSL_FALLBACK, test_fallback);
+ g_test_add ("/tls/connection/fallback/subprocess/" PRIORITY_SSL_FALLBACK,
+ TestConnection, NULL,
+ setup_connection, test_fallback_subprocess, teardown_connection);
+ g_test_add_data_func ("/tls/connection/fallback/TLS", PRIORITY_TLS_FALLBACK, test_fallback);
+ g_test_add ("/tls/connection/fallback/subprocess/" PRIORITY_TLS_FALLBACK,
+ TestConnection, NULL,
+ setup_connection, test_fallback_subprocess, teardown_connection);
+
ret = g_test_run();
/* for valgrinding */
--
2.1.0

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@ -0,0 +1,78 @@
From f474ec2a887f2ef1dba536683f5a7c8b6dc7e283 Mon Sep 17 00:00:00 2001
From: Dan Winship <danw@gnome.org>
Date: Thu, 13 Nov 2014 22:30:13 -0500
Subject: [PATCH 2/2] gnutls: update default priority string and fallback rules
Change the default "priority" string from "NORMAL:%COMPAT" to
"NORMAL:%COMPAT:%LATEST_RECORD_VERSION". (Correctly-implemented
servers won't care either way, but apparently some servers have been
incorrectly updated for POODLE-safeness by rejecting all handshakes
with SSL 3.0 in the version field [which had long been recommended for
compatibility reasons], even if the handshake offered to negotiate TLS
versions too.)
Change the fallback/"ssl3" priority code so that it never includes
%LATEST_RECORD_VERSION, but does include %COMPAT even if the default
priority doesn't (eg, because it was overridden with
G_TLS_GNUTLS_PRIORITY).
https://bugzilla.gnome.org/show_bug.cgi?id=740087
---
tls/gnutls/gtlsconnection-gnutls.c | 23 +++++++++++++++++++----
1 file changed, 19 insertions(+), 4 deletions(-)
diff --git a/tls/gnutls/gtlsconnection-gnutls.c b/tls/gnutls/gtlsconnection-gnutls.c
index 444ca36..7436451 100644
--- a/tls/gnutls/gtlsconnection-gnutls.c
+++ b/tls/gnutls/gtlsconnection-gnutls.c
@@ -197,6 +197,8 @@ g_tls_connection_gnutls_init (GTlsConnectionGnutls *gnutls)
/* First field is "fallback", second is "allow unsafe rehandshaking" */
static gnutls_priority_t priorities[2][2];
+#define DEFAULT_BASE_PRIORITY "NORMAL:%COMPAT:%LATEST_RECORD_VERSION"
+
static void
g_tls_connection_gnutls_init_priorities (void)
{
@@ -207,12 +209,12 @@ g_tls_connection_gnutls_init_priorities (void)
base_priority = g_getenv ("G_TLS_GNUTLS_PRIORITY");
if (!base_priority)
- base_priority = "NORMAL:%COMPAT";
+ base_priority = DEFAULT_BASE_PRIORITY;
ret = gnutls_priority_init (&priorities[FALSE][FALSE], base_priority, NULL);
if (ret == GNUTLS_E_INVALID_REQUEST)
{
g_warning ("G_TLS_GNUTLS_PRIORITY is invalid; ignoring!");
- base_priority = "NORMAL:%COMPAT";
+ base_priority = DEFAULT_BASE_PRIORITY;
gnutls_priority_init (&priorities[FALSE][FALSE], base_priority, NULL);
}
@@ -236,8 +238,21 @@ g_tls_connection_gnutls_init_priorities (void)
}
else
{
- fallback_priority = g_strdup_printf ("%s:!VERS-TLS-ALL:+VERS-%s",
- base_priority,
+ gchar *cleaned_base, *p, *rest;
+
+ /* fallback_priority should be based on base_priority, except
+ * that we don't want %LATEST_RECORD_VERSION in it.
+ */
+ cleaned_base = g_strdup (base_priority);
+ p = strstr (cleaned_base, ":%LATEST_RECORD_VERSION");
+ if (p)
+ {
+ rest = p + strlen (":%LATEST_RECORD_VERSION");
+ memmove (p, rest, strlen (rest) + 1);
+ }
+
+ fallback_priority = g_strdup_printf ("%s:%%COMPAT:!VERS-TLS-ALL:+VERS-%s",
+ cleaned_base,
gnutls_protocol_get_name (fallback_proto));
}
fallback_unsafe_rehandshake_priority = g_strdup_printf ("%s:%%UNSAFE_RENEGOTIATION",
--
2.1.0

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@ -2,7 +2,7 @@
Name: glib-networking
Version: 2.42.0
Release: 1%{?dist}
Release: 2%{?dist}
Summary: Networking support for GLib
Group: Development/Libraries
@ -10,6 +10,9 @@ License: LGPLv2+
URL: http://www.gnome.org
Source: http://download.gnome.org/sources/glib-networking/2.42/%{name}-%{version}.tar.xz
Patch1: 0001-rh1177964-fallback-semantics.patch
Patch2: 0002-rh1177964-priority-string.patch
BuildRequires: glib2-devel >= %{glib2_version}
BuildRequires: libproxy-devel
BuildRequires: gnutls-devel
@ -38,6 +41,8 @@ the functionality of the installed glib-networking package.
%prep
%setup -q
%patch1 -p1 -b .0001-rh1177964-fallback-semantics.patch
%patch2 -p1 -b .0002-rh1177964-priority-string.patch
%build
@ -72,6 +77,9 @@ gio-querymodules-%{__isa_bits} %{_libdir}/gio/modules
%{_datadir}/installed-tests
%changelog
* Fri Mar 6 2015 Dan Winship <danw@redhat.com> - 2.42.0-2
- Improve priority string and fallback rules for the post-POODLE world (#1177964)
* Mon Sep 22 2014 Kalev Lember <kalevlember@gmail.com> - 2.42.0-1
- Update to 2.42.0