glib/gio/gtlsbackend.c
Philip Withnall 5e55a4e243 gtlsbackend: Default to indicating no support for DTLS in GTlsBackend
I’m unsure what the original reasoning for returning TRUE by default
from supports_dtls was, but it is not backwards-compatible. If a
pre-existing GTlsBackend implementation never implements the
supports_dtls vfunc, the supports_dtls() method will magically return
TRUE rather than FALSE.

Since any backend which does implement DTLS should be implementing the
supports_dtls vfunc (and no DTLS-supporting backends have actually been
merged yet; see bug #697908), it seems safer to make this slight API
break in the name of backwards compatibility than to leave it as
returning TRUE incorrectly.

Signed-off-by: Philip Withnall <withnall@endlessm.com>

https://bugzilla.gnome.org/show_bug.cgi?id=787485
2017-09-13 17:38:42 +01:00

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/* GIO - GLib Input, Output and Streaming Library
*
* Copyright © 2010 Red Hat, Inc
* Copyright © 2015 Collabora, Ltd.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General
* Public License along with this library; if not, see <http://www.gnu.org/licenses/>.
*/
#include "config.h"
#include "glib.h"
#include "gtlsbackend.h"
#include "gdummytlsbackend.h"
#include "gioenumtypes.h"
#include "giomodule-priv.h"
/**
* SECTION:gtls
* @title: TLS Overview
* @short_description: TLS (aka SSL) support for GSocketConnection
* @include: gio/gio.h
*
* #GTlsConnection and related classes provide TLS (Transport Layer
* Security, previously known as SSL, Secure Sockets Layer) support for
* gio-based network streams.
*
* #GDtlsConnection and related classes provide DTLS (Datagram TLS) support for
* GIO-based network sockets, using the #GDatagramBased interface. The TLS and
* DTLS APIs are almost identical, except TLS is stream-based and DTLS is
* datagram-based. They share certificate and backend infrastructure.
*
* In the simplest case, for a client TLS connection, you can just set the
* #GSocketClient:tls flag on a #GSocketClient, and then any
* connections created by that client will have TLS negotiated
* automatically, using appropriate default settings, and rejecting
* any invalid or self-signed certificates (unless you change that
* default by setting the #GSocketClient:tls-validation-flags
* property). The returned object will be a #GTcpWrapperConnection,
* which wraps the underlying #GTlsClientConnection.
*
* For greater control, you can create your own #GTlsClientConnection,
* wrapping a #GSocketConnection (or an arbitrary #GIOStream with
* pollable input and output streams) and then connect to its signals,
* such as #GTlsConnection::accept-certificate, before starting the
* handshake.
*
* Server-side TLS is similar, using #GTlsServerConnection. At the
* moment, there is no support for automatically wrapping server-side
* connections in the way #GSocketClient does for client-side
* connections.
*/
/**
* SECTION:gtlsbackend
* @title: GTlsBackend
* @short_description: TLS backend implementation
* @include: gio/gio.h
*
* TLS (Transport Layer Security, aka SSL) and DTLS backend.
*
* Since: 2.28
*/
/**
* GTlsBackend:
*
* TLS (Transport Layer Security, aka SSL) and DTLS backend. This is an
* internal type used to coordinate the different classes implemented
* by a TLS backend.
*
* Since: 2.28
*/
G_DEFINE_INTERFACE (GTlsBackend, g_tls_backend, G_TYPE_OBJECT)
static void
g_tls_backend_default_init (GTlsBackendInterface *iface)
{
}
/**
* g_tls_backend_get_default:
*
* Gets the default #GTlsBackend for the system.
*
* Returns: (transfer none): a #GTlsBackend
*
* Since: 2.28
*/
GTlsBackend *
g_tls_backend_get_default (void)
{
return _g_io_module_get_default (G_TLS_BACKEND_EXTENSION_POINT_NAME,
"GIO_USE_TLS", NULL);
}
/**
* g_tls_backend_supports_tls:
* @backend: the #GTlsBackend
*
* Checks if TLS is supported; if this returns %FALSE for the default
* #GTlsBackend, it means no "real" TLS backend is available.
*
* Returns: whether or not TLS is supported
*
* Since: 2.28
*/
gboolean
g_tls_backend_supports_tls (GTlsBackend *backend)
{
if (G_TLS_BACKEND_GET_INTERFACE (backend)->supports_tls)
return G_TLS_BACKEND_GET_INTERFACE (backend)->supports_tls (backend);
else if (G_IS_DUMMY_TLS_BACKEND (backend))
return FALSE;
else
return TRUE;
}
/**
* g_tls_backend_supports_dtls:
* @backend: the #GTlsBackend
*
* Checks if DTLS is supported. DTLS support may not be available even if TLS
* support is available, and vice-versa.
*
* Returns: whether DTLS is supported
*
* Since: 2.48
*/
gboolean
g_tls_backend_supports_dtls (GTlsBackend *backend)
{
if (G_TLS_BACKEND_GET_INTERFACE (backend)->supports_dtls)
return G_TLS_BACKEND_GET_INTERFACE (backend)->supports_dtls (backend);
return FALSE;
}
/**
* g_tls_backend_get_default_database:
* @backend: the #GTlsBackend
*
* Gets the default #GTlsDatabase used to verify TLS connections.
*
* Returns: (transfer full): the default database, which should be
* unreffed when done.
*
* Since: 2.30
*/
GTlsDatabase *
g_tls_backend_get_default_database (GTlsBackend *backend)
{
g_return_val_if_fail (G_IS_TLS_BACKEND (backend), NULL);
/* This method was added later, so accept the (remote) possibility it can be NULL */
if (!G_TLS_BACKEND_GET_INTERFACE (backend)->get_default_database)
return NULL;
return G_TLS_BACKEND_GET_INTERFACE (backend)->get_default_database (backend);
}
/**
* g_tls_backend_get_certificate_type:
* @backend: the #GTlsBackend
*
* Gets the #GType of @backend's #GTlsCertificate implementation.
*
* Returns: the #GType of @backend's #GTlsCertificate
* implementation.
*
* Since: 2.28
*/
GType
g_tls_backend_get_certificate_type (GTlsBackend *backend)
{
return G_TLS_BACKEND_GET_INTERFACE (backend)->get_certificate_type ();
}
/**
* g_tls_backend_get_client_connection_type:
* @backend: the #GTlsBackend
*
* Gets the #GType of @backend's #GTlsClientConnection implementation.
*
* Returns: the #GType of @backend's #GTlsClientConnection
* implementation.
*
* Since: 2.28
*/
GType
g_tls_backend_get_client_connection_type (GTlsBackend *backend)
{
return G_TLS_BACKEND_GET_INTERFACE (backend)->get_client_connection_type ();
}
/**
* g_tls_backend_get_server_connection_type:
* @backend: the #GTlsBackend
*
* Gets the #GType of @backend's #GTlsServerConnection implementation.
*
* Returns: the #GType of @backend's #GTlsServerConnection
* implementation.
*
* Since: 2.28
*/
GType
g_tls_backend_get_server_connection_type (GTlsBackend *backend)
{
return G_TLS_BACKEND_GET_INTERFACE (backend)->get_server_connection_type ();
}
/**
* g_tls_backend_get_dtls_client_connection_type:
* @backend: the #GTlsBackend
*
* Gets the #GType of @backends #GDtlsClientConnection implementation.
*
* Returns: the #GType of @backends #GDtlsClientConnection
* implementation, or %G_TYPE_INVALID if this backend doesnt support DTLS.
*
* Since: 2.48
*/
GType
g_tls_backend_get_dtls_client_connection_type (GTlsBackend *backend)
{
GTlsBackendInterface *iface;
g_return_val_if_fail (G_IS_TLS_BACKEND (backend), G_TYPE_INVALID);
iface = G_TLS_BACKEND_GET_INTERFACE (backend);
if (iface->get_dtls_client_connection_type == NULL)
return G_TYPE_INVALID;
return iface->get_dtls_client_connection_type ();
}
/**
* g_tls_backend_get_dtls_server_connection_type:
* @backend: the #GTlsBackend
*
* Gets the #GType of @backends #GDtlsServerConnection implementation.
*
* Returns: the #GType of @backends #GDtlsServerConnection
* implementation, or %G_TYPE_INVALID if this backend doesnt support DTLS.
*
* Since: 2.48
*/
GType
g_tls_backend_get_dtls_server_connection_type (GTlsBackend *backend)
{
GTlsBackendInterface *iface;
g_return_val_if_fail (G_IS_TLS_BACKEND (backend), G_TYPE_INVALID);
iface = G_TLS_BACKEND_GET_INTERFACE (backend);
if (iface->get_dtls_server_connection_type == NULL)
return G_TYPE_INVALID;
return iface->get_dtls_server_connection_type ();
}
/**
* g_tls_backend_get_file_database_type:
* @backend: the #GTlsBackend
*
* Gets the #GType of @backend's #GTlsFileDatabase implementation.
*
* Returns: the #GType of backend's #GTlsFileDatabase implementation.
*
* Since: 2.30
*/
GType
g_tls_backend_get_file_database_type (GTlsBackend *backend)
{
g_return_val_if_fail (G_IS_TLS_BACKEND (backend), 0);
/* This method was added later, so accept the (remote) possibility it can be NULL */
if (!G_TLS_BACKEND_GET_INTERFACE (backend)->get_file_database_type)
return 0;
return G_TLS_BACKEND_GET_INTERFACE (backend)->get_file_database_type ();
}