/* GIO - GLib Input, Output and Streaming Library

 *

 * Copyright © 2010 Red Hat, Inc

 *

 * SPDX-License-Identifier: LGPL-2.1-or-later

 *

 * 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 "gtlsclientconnection.h"

#include "ginitable.h"

#include "gioenumtypes.h"

#include "gsocket.h"

#include "gsocketconnectable.h"

#include "gtlsbackend.h"

#include "gtlscertificate.h"

#include "glibintl.h"

/**

 * SECTION:gtlsclientconnection

 * @short_description: TLS client-side connection

 * @include: gio/gio.h

 *

 * #GTlsClientConnection is the client-side subclass of

 * #GTlsConnection, representing a client-side TLS connection.

 */

/**

 * GTlsClientConnection:

 *

 * Abstract base class for the backend-specific client connection

 * type.

 *

 * Since: 2.28

 */

G_DEFINE_INTERFACE (GTlsClientConnection, g_tls_client_connection, G_TYPE_TLS_CONNECTION)

static void

g_tls_client_connection_default_init (GTlsClientConnectionInterface *iface)

{

  /**

   * GTlsClientConnection:validation-flags:

   *

   * What steps to perform when validating a certificate received from

   * a server. Server certificates that fail to validate in any of the

   * ways indicated here will be rejected unless the application

   * overrides the default via #GTlsConnection::accept-certificate.

   *

   * GLib guarantees that if certificate verification fails, at least one

   * flag will be set, but it does not guarantee that all possible flags

   * will be set. Accordingly, you may not safely decide to ignore any

   * particular type of error. For example, it would be incorrect to mask

   * %G_TLS_CERTIFICATE_EXPIRED if you want to allow expired certificates,

   * because this could potentially be the only error flag set even if

   * other problems exist with the certificate. Therefore, there is no

   * safe way to use this property. This is not a horrible problem,

   * though, because you should not be attempting to ignore validation

   * errors anyway. If you really must ignore TLS certificate errors,

   * connect to #GTlsConnection::accept-certificate.

   *

   * Since: 2.28

   *

   * Deprecated: 2.72: Do not attempt to ignore validation errors.

   */

  g_object_interface_install_property (iface,

               g_param_spec_flags ("validation-flags",

                 P_("Validation flags"),

                 P_("What certificate validation to perform"),

                 G_TYPE_TLS_CERTIFICATE_FLAGS,

                 G_TLS_CERTIFICATE_VALIDATE_ALL,

                 G_PARAM_READWRITE |

                 G_PARAM_CONSTRUCT |

                 G_PARAM_STATIC_STRINGS |

                 G_PARAM_DEPRECATED));

  /**

   * GTlsClientConnection:server-identity:

   *

   * A #GSocketConnectable describing the identity of the server that

   * is expected on the other end of the connection.

   *

   * If the %G_TLS_CERTIFICATE_BAD_IDENTITY flag is set in

   * #GTlsClientConnection:validation-flags, this object will be used

   * to determine the expected identify of the remote end of the

   * connection; if #GTlsClientConnection:server-identity is not set,

   * or does not match the identity presented by the server, then the

   * %G_TLS_CERTIFICATE_BAD_IDENTITY validation will fail.

   *

   * In addition to its use in verifying the server certificate,

   * this is also used to give a hint to the server about what

   * certificate we expect, which is useful for servers that serve

   * virtual hosts.

   *

   * Since: 2.28

   */

  g_object_interface_install_property (iface,

               g_param_spec_object ("server-identity",

                  P_("Server identity"),

                  P_("GSocketConnectable identifying the server"),

                  G_TYPE_SOCKET_CONNECTABLE,

                  G_PARAM_READWRITE |

                  G_PARAM_CONSTRUCT |

                  G_PARAM_STATIC_STRINGS));

  /**

   * GTlsClientConnection:use-ssl3:

   *

   * SSL 3.0 is no longer supported. See

   * g_tls_client_connection_set_use_ssl3() for details.

   *

   * Since: 2.28

   *

   * Deprecated: 2.56: SSL 3.0 is insecure.

   */

  g_object_interface_install_property (iface,

               g_param_spec_boolean ("use-ssl3",

                   P_("Use fallback"),

                   P_("Use fallback version of SSL/TLS rather than most recent version"),

                   FALSE,

                   G_PARAM_READWRITE |

                   G_PARAM_CONSTRUCT |

                   G_PARAM_STATIC_STRINGS |

                   G_PARAM_DEPRECATED));

  /**

   * GTlsClientConnection:accepted-cas: (type GLib.List) (element-type GLib.ByteArray)

   *

   * A list of the distinguished names of the Certificate Authorities

   * that the server will accept client certificates signed by. If the

   * server requests a client certificate during the handshake, then

   * this property will be set after the handshake completes.

   *

   * Each item in the list is a #GByteArray which contains the complete

   * subject DN of the certificate authority.

   *

   * Since: 2.28

   */

  g_object_interface_install_property (iface,

               g_param_spec_pointer ("accepted-cas",

                   P_("Accepted CAs"),

                   P_("Distinguished names of the CAs the server accepts certificates from"),

                   G_PARAM_READABLE |

                   G_PARAM_STATIC_STRINGS));

}

/**

 * g_tls_client_connection_new:

 * @base_io_stream: the #GIOStream to wrap

 * @server_identity: (nullable): the expected identity of the server

 * @error: #GError for error reporting, or %NULL to ignore.

 *

 * Creates a new #GTlsClientConnection wrapping @base_io_stream (which

 * must have pollable input and output streams) which is assumed to

 * communicate with the server identified by @server_identity.

 *

 * See the documentation for #GTlsConnection:base-io-stream for restrictions

 * on when application code can run operations on the @base_io_stream after

 * this function has returned.

 *

 * Returns: (transfer full) (type GTlsClientConnection): the new

 * #GTlsClientConnection, or %NULL on error

 *

 * Since: 2.28

 */

GIOStream *

g_tls_client_connection_new (GIOStream           *base_io_stream,

           GSocketConnectable  *server_identity,

           GError             **error)

{

  GObject *conn;

  GTlsBackend *backend;

  backend = g_tls_backend_get_default ();

  conn = g_initable_new (g_tls_backend_get_client_connection_type (backend),

       NULL, error,

       "base-io-stream", base_io_stream,

       "server-identity", server_identity,

       NULL);

  return G_IO_STREAM (conn);

}

/**

 * g_tls_client_connection_get_validation_flags:

 * @conn: the #GTlsClientConnection

 *

 * Gets @conn's validation flags

 *

 * This function does not work as originally designed and is impossible

 * to use correctly. See #GTlsClientConnection:validation-flags for more

 * information.

 *

 * Returns: the validation flags

 *

 * Since: 2.28

 *

 * Deprecated: 2.72: Do not attempt to ignore validation errors.

 */

GTlsCertificateFlags

g_tls_client_connection_get_validation_flags (GTlsClientConnection *conn)

{

  GTlsCertificateFlags flags = G_TLS_CERTIFICATE_NO_FLAGS;

  g_return_val_if_fail (G_IS_TLS_CLIENT_CONNECTION (conn), 0);

  g_object_get (G_OBJECT (conn), "validation-flags", &flags, NULL);

  return flags;

}

/**

 * g_tls_client_connection_set_validation_flags:

 * @conn: the #GTlsClientConnection

 * @flags: the #GTlsCertificateFlags to use

 *

 * Sets @conn's validation flags, to override the default set of

 * checks performed when validating a server certificate. By default,

 * %G_TLS_CERTIFICATE_VALIDATE_ALL is used.

 *

 * This function does not work as originally designed and is impossible

 * to use correctly. See #GTlsClientConnection:validation-flags for more

 * information.

 *

 * Since: 2.28

 *

 * Deprecated: 2.72: Do not attempt to ignore validation errors.

 */

void

g_tls_client_connection_set_validation_flags (GTlsClientConnection  *conn,

                GTlsCertificateFlags   flags)

{

  g_return_if_fail (G_IS_TLS_CLIENT_CONNECTION (conn));

  g_object_set (G_OBJECT (conn), "validation-flags", flags, NULL);

}

/**

 * g_tls_client_connection_get_server_identity:

 * @conn: the #GTlsClientConnection

 *

 * Gets @conn's expected server identity

 *

 * Returns: (nullable) (transfer none): a #GSocketConnectable describing the

 * expected server identity, or %NULL if the expected identity is not

 * known.

 *

 * Since: 2.28

 */

GSocketConnectable *

g_tls_client_connection_get_server_identity (GTlsClientConnection *conn)

{

  GSocketConnectable *identity = NULL;

  g_return_val_if_fail (G_IS_TLS_CLIENT_CONNECTION (conn), 0);

  g_object_get (G_OBJECT (conn), "server-identity", &identity, NULL);

  if (identity)

    g_object_unref (identity);

  return identity;

}

/**

 * g_tls_client_connection_set_server_identity:

 * @conn: the #GTlsClientConnection

 * @identity: a #GSocketConnectable describing the expected server identity

 *

 * Sets @conn's expected server identity, which is used both to tell

 * servers on virtual hosts which certificate to present, and also

 * to let @conn know what name to look for in the certificate when

 * performing %G_TLS_CERTIFICATE_BAD_IDENTITY validation, if enabled.

 *

 * Since: 2.28

 */

void

g_tls_client_connection_set_server_identity (GTlsClientConnection *conn,

               GSocketConnectable   *identity)

{

  g_return_if_fail (G_IS_TLS_CLIENT_CONNECTION (conn));

  g_object_set (G_OBJECT (conn), "server-identity", identity, NULL);

}

/**

 * g_tls_client_connection_get_use_ssl3:

 * @conn: the #GTlsClientConnection

 *

 * SSL 3.0 is no longer supported. See

 * g_tls_client_connection_set_use_ssl3() for details.

 *

 * Returns: %FALSE

 *

 * Since: 2.28

 *

 * Deprecated: 2.56: SSL 3.0 is insecure.

 */

gboolean

g_tls_client_connection_get_use_ssl3 (GTlsClientConnection *conn)

{

  gboolean use_ssl3 = FALSE;

  g_return_val_if_fail (G_IS_TLS_CLIENT_CONNECTION (conn), 0);

  g_object_get (G_OBJECT (conn), "use-ssl3", &use_ssl3, NULL);

  return FALSE;

}

/**

 * g_tls_client_connection_set_use_ssl3:

 * @conn: the #GTlsClientConnection

 * @use_ssl3: a #gboolean, ignored

 *

 * Since GLib 2.42.1, SSL 3.0 is no longer supported.

 *

 * From GLib 2.42.1 through GLib 2.62, this function could be used to

 * force use of TLS 1.0, the lowest-supported TLS protocol version at

 * the time. In the past, this was needed to connect to broken TLS

 * servers that exhibited protocol version intolerance. Such servers

 * are no longer common, and using TLS 1.0 is no longer considered

 * acceptable.

 *

 * Since GLib 2.64, this function does nothing.

 *

 * Since: 2.28

 *

 * Deprecated: 2.56: SSL 3.0 is insecure.

 */

void

g_tls_client_connection_set_use_ssl3 (GTlsClientConnection *conn,

              gboolean              use_ssl3)

{

  g_return_if_fail (G_IS_TLS_CLIENT_CONNECTION (conn));

  g_object_set (G_OBJECT (conn), "use-ssl3", FALSE, NULL);

}

/**

 * g_tls_client_connection_get_accepted_cas:

 * @conn: the #GTlsClientConnection

 *

 * Gets the list of distinguished names of the Certificate Authorities

 * that the server will accept certificates from. This will be set

 * during the TLS handshake if the server requests a certificate.

 * Otherwise, it will be %NULL.

 *

 * Each item in the list is a #GByteArray which contains the complete

 * subject DN of the certificate authority.

 *

 * Returns: (element-type GByteArray) (transfer full): the list of

 * CA DNs. You should unref each element with g_byte_array_unref() and then

 * the free the list with g_list_free().

 *

 * Since: 2.28

 */

GList *

g_tls_client_connection_get_accepted_cas (GTlsClientConnection *conn)

{

  GList *accepted_cas = NULL;

  g_return_val_if_fail (G_IS_TLS_CLIENT_CONNECTION (conn), NULL);

  g_object_get (G_OBJECT (conn), "accepted-cas", &accepted_cas, NULL);

  return accepted_cas;

}

/**

 * g_tls_client_connection_copy_session_state:

 * @conn: a #GTlsClientConnection

 * @source: a #GTlsClientConnection

 *

 * Possibly copies session state from one connection to another, for use

 * in TLS session resumption. This is not normally needed, but may be

 * used when the same session needs to be used between different

 * endpoints, as is required by some protocols, such as FTP over TLS.

 * @source should have already completed a handshake and, since TLS 1.3,

 * it should have been used to read data at least once. @conn should not

 * have completed a handshake.

 *

 * It is not possible to know whether a call to this function will

 * actually do anything. Because session resumption is normally used

 * only for performance benefit, the TLS backend might not implement

 * this function. Even if implemented, it may not actually succeed in

 * allowing @conn to resume @source's TLS session, because the server

 * may not have sent a session resumption token to @source, or it may

 * refuse to accept the token from @conn. There is no way to know

 * whether a call to this function is actually successful.

 *

 * Using this function is not required to benefit from session

 * resumption. If the TLS backend supports session resumption, the

 * session will be resumed automatically if it is possible to do so

 * without weakening the privacy guarantees normally provided by TLS,

 * without need to call this function. For example, with TLS 1.3,

 * a session ticket will be automatically copied from any

 * #GTlsClientConnection that has previously received session tickets

 * from the server, provided a ticket is available that has not

 * previously been used for session resumption, since session ticket

 * reuse would be a privacy weakness. Using this function causes the

 * ticket to be copied without regard for privacy considerations.

 *

 * Since: 2.46

 */

void

g_tls_client_connection_copy_session_state (GTlsClientConnection *conn,

                                            GTlsClientConnection *source)

{

  g_return_if_fail (G_IS_TLS_CLIENT_CONNECTION (conn));

  g_return_if_fail (G_IS_TLS_CLIENT_CONNECTION (source));

  g_return_if_fail (G_TLS_CLIENT_CONNECTION_GET_INTERFACE (conn)->copy_session_state != NULL);

  G_TLS_CLIENT_CONNECTION_GET_INTERFACE (conn)->copy_session_state (conn,

                                                                    source);

}