glib/gio/gtlsclientconnection.c
Michael Catanzaro 08fe93589e Update documentation of g_tls_client_connection_set_use_ssl3()
We now send the fallback SCSV, meaning use of this function will cause
modern servers to immediately terminate the connection, so let's warn
API users to expect that behavior and be crystal clear that this
function should only be used as a fallback when a normal connection
attempt has already failed.

Also, the documentation is mostly duplicated between the property and
the function, so let's just reference the function documentation from
the property.
2018-08-04 16:33:28 -05:00

382 lines
12 KiB
C

/* GIO - GLib Input, Output and Streaming Library
*
* Copyright © 2010 Red Hat, Inc
*
* 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 all of the
* ways indicated here will be rejected unless the application
* overrides the default via #GTlsConnection::accept-certificate.
*
* Since: 2.28
*/
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));
/**
* 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:
*
* If %TRUE, forces the connection to use a fallback version of TLS
* or SSL, rather than trying to negotiate the best version of TLS
* to use. See g_tls_client_connection_set_use_ssl3().
*
* Since: 2.28
*
* Deprecated: 2.56: SSL 3.0 is insecure, and this property does not
* generally enable or disable it, despite its name.
*/
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
*
* Returns: the validation flags
*
* Since: 2.28
*/
GTlsCertificateFlags
g_tls_client_connection_get_validation_flags (GTlsClientConnection *conn)
{
GTlsCertificateFlags flags = 0;
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.
*
* Since: 2.28
*/
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: (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
*
* Gets whether @conn will force the lowest-supported TLS protocol
* version rather than attempt to negotiate the highest mutually-
* supported version of TLS; see g_tls_client_connection_set_use_ssl3().
*
* Returns: whether @conn will use the lowest-supported TLS protocol version
*
* Since: 2.28
*
* Deprecated: 2.56: SSL 3.0 is insecure, and this function does not
* actually indicate whether it is enabled.
*/
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 use_ssl3;
}
/**
* g_tls_client_connection_set_use_ssl3:
* @conn: the #GTlsClientConnection
* @use_ssl3: whether to use the lowest-supported protocol version
*
* Since 2.42.1, if @use_ssl3 is %TRUE, this forces @conn to use the
* lowest-supported TLS protocol version rather than trying to properly
* negotiate the highest mutually-supported protocol version with the
* peer. Be aware that SSL 3.0 is generally disabled by the
* #GTlsBackend, so the lowest-supported protocol version is probably
* not SSL 3.0.
*
* Since 2.58, this may additionally cause an RFC 7507 fallback SCSV to
* be sent to the server, causing modern TLS servers to immediately
* terminate the connection. You should generally only use this function
* if you need to connect to broken servers that exhibit TLS protocol
* version intolerance, and when an initial attempt to connect to a
* server normally has already failed.
*
* Since: 2.28
*
* Deprecated: 2.56: SSL 3.0 is insecure, and this function does not
* generally enable or disable it, despite its name.
*/
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", use_ssl3, 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
*
* Copies session state from one connection to another. 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 @conn should not have
* completed a handshake.
*
* 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);
}