GTlsConnection

GTlsConnection — TLS connection type

Synopsis


#include <gio/gio.h>

                    GTlsConnection;
void                g_tls_connection_set_certificate    (GTlsConnection *conn,
                                                         GTlsCertificate *certificate);
GTlsCertificate *   g_tls_connection_get_certificate    (GTlsConnection *conn);
GTlsCertificate *   g_tls_connection_get_peer_certificate
                                                        (GTlsConnection *conn);
GTlsCertificateFlags  g_tls_connection_get_peer_certificate_errors
                                                        (GTlsConnection *conn);
void                g_tls_connection_set_require_close_notify
                                                        (GTlsConnection *conn,
                                                         gboolean require_close_notify);
gboolean            g_tls_connection_get_require_close_notify
                                                        (GTlsConnection *conn);
enum                GTlsRehandshakeMode;
void                g_tls_connection_set_rehandshake_mode
                                                        (GTlsConnection *conn,
                                                         GTlsRehandshakeMode mode);
GTlsRehandshakeMode  g_tls_connection_get_rehandshake_mode
                                                        (GTlsConnection *conn);
void                g_tls_connection_set_use_system_certdb
                                                        (GTlsConnection *conn,
                                                         gboolean use_system_certdb);
gboolean            g_tls_connection_get_use_system_certdb
                                                        (GTlsConnection *conn);

gboolean            g_tls_connection_handshake          (GTlsConnection *conn,
                                                         GCancellable *cancellable,
                                                         GError **error);
void                g_tls_connection_handshake_async    (GTlsConnection *conn,
                                                         int io_priority,
                                                         GCancellable *cancellable,
                                                         GAsyncReadyCallback callback,
                                                         gpointer user_data);
gboolean            g_tls_connection_handshake_finish   (GTlsConnection *conn,
                                                         GAsyncResult *result,
                                                         GError **error);

gboolean            g_tls_connection_emit_accept_certificate
                                                        (GTlsConnection *conn,
                                                         GTlsCertificate *peer_cert,
                                                         GTlsCertificateFlags errors);

Description

GTlsConnection is the base TLS connection class type, which wraps a GIOStream and provides TLS encryption on top of it. Its subclasses, GTlsClientConnection and GTlsServerConnection, implement client-side and server-side TLS, respectively.

Details

GTlsConnection

typedef struct {
  GIOStream parent_instance;

  GTlsConnectionPrivate *priv;
} GTlsConnection;

TLS connection. This is an abstract type that will be subclassed by a TLS-library-specific subtype.

Since 2.28


g_tls_connection_set_certificate ()

void                g_tls_connection_set_certificate    (GTlsConnection *conn,
                                                         GTlsCertificate *certificate);

This sets the certificate that conn will present to its peer during the TLS handshake. For a GTlsServerConnection, it is mandatory to set this, and that will normally be done at construct time.

For a GTlsClientConnection, this is optional. If a handshake fails with G_TLS_ERROR_CERTIFICATE_REQUIRED, that means that the server requires a certificate, and if you try connecting again, you should call this method first. You can call g_tls_client_connection_get_accepted_cas() on the failed connection to get a list of Certificate Authorities that the server will accept certificates from.

(It is also possible that a server will allow the connection with or without a certificate; in that case, if you don't provide a certificate, you can tell that the server requested one by the fact that g_tls_client_connection_get_accepted_cas() will return non-NULL.)

conn :

a GTlsConnection

certificate :

the certificate to use for conn

Since 2.28


g_tls_connection_get_certificate ()

GTlsCertificate *   g_tls_connection_get_certificate    (GTlsConnection *conn);

Gets conn's certificate, as set by g_tls_connection_set_certificate().

conn :

a GTlsConnection

Returns :

conn's certificate, or NULL. transfer none.

Since 2.28


g_tls_connection_get_peer_certificate ()

GTlsCertificate *   g_tls_connection_get_peer_certificate
                                                        (GTlsConnection *conn);

Gets conn's peer's certificate after the handshake has completed. (It is not set during the emission of "accept-certificate".)

conn :

a GTlsConnection

Returns :

conn's peer's certificate, or NULL. transfer none.

Since 2.28


g_tls_connection_get_peer_certificate_errors ()

GTlsCertificateFlags  g_tls_connection_get_peer_certificate_errors
                                                        (GTlsConnection *conn);

Gets the errors associated with validating conn's peer's certificate, after the handshake has completed. (It is not set during the emission of "accept-certificate".)

conn :

a GTlsConnection

Returns :

conn's peer's certificate errors

Since 2.28


g_tls_connection_set_require_close_notify ()

void                g_tls_connection_set_require_close_notify
                                                        (GTlsConnection *conn,
                                                         gboolean require_close_notify);

Sets whether or not conn expects a proper TLS close notification before the connection is closed. If this is TRUE (the default), then conn will expect to receive a TLS close notification from its peer before the connection is closed, and will return a G_TLS_ERROR_EOF error if the connection is closed without proper notification (since this may indicate a network error, or man-in-the-middle attack).

In some protocols, the application will know whether or not the connection was closed cleanly based on application-level data (because the application-level data includes a length field, or is somehow self-delimiting); in this case, the close notify is redundant and sometimes omitted. (TLS 1.1 explicitly allows this; in TLS 1.0 it is technically an error, but often done anyway.) You can use g_tls_connection_set_require_close_notify() to tell conn to allow an "unannounced" connection close, in which case the close will show up as a 0-length read, as in a non-TLS GSocketConnection, and it is up to the application to check that the data has been fully received.

Note that this only affects the behavior when the peer closes the connection; when the application calls g_io_stream_close() itself on conn, this will send a close notification regardless of the setting of this property. If you explicitly want to do an unclean close, you can close conn's "base-io-stream" rather than closing conn itself.

conn :

a GTlsConnection

require_close_notify :

whether or not to require close notification

Since 2.28


g_tls_connection_get_require_close_notify ()

gboolean            g_tls_connection_get_require_close_notify
                                                        (GTlsConnection *conn);

Tests whether or not conn expects a proper TLS close notification when the connection is closed. See g_tls_connection_set_require_close_notify() for details.

conn :

a GTlsConnection

Returns :

TRUE if conn requires a proper TLS close notification.

Since 2.28


enum GTlsRehandshakeMode

typedef enum {
  G_TLS_REHANDSHAKE_NEVER,
  G_TLS_REHANDSHAKE_SAFELY,
  G_TLS_REHANDSHAKE_UNSAFELY
} GTlsRehandshakeMode;

When to allow rehandshaking. See g_tls_connection_set_rehandshake_mode().

G_TLS_REHANDSHAKE_NEVER

Never allow rehandshaking

G_TLS_REHANDSHAKE_SAFELY

Allow safe rehandshaking only

G_TLS_REHANDSHAKE_UNSAFELY

Allow unsafe rehandshaking

Since 2.28


g_tls_connection_set_rehandshake_mode ()

void                g_tls_connection_set_rehandshake_mode
                                                        (GTlsConnection *conn,
                                                         GTlsRehandshakeMode mode);

Sets how conn behaves with respect to rehandshaking requests.

G_TLS_REHANDSHAKE_NEVER means that it will never agree to rehandshake after the initial handshake is complete. (For a client, this means it will refuse rehandshake requests from the server, and for a server, this means it will close the connection with an error if the client attempts to rehandshake.)

G_TLS_REHANDSHAKE_SAFELY means that the connection will allow a rehandshake only if the other end of the connection supports the TLS renegotiation_info extension. This is the default behavior, but means that rehandshaking will not work against older implementations that do not support that extension.

G_TLS_REHANDSHAKE_UNSAFELY means that the connection will allow rehandshaking even without the renegotiation_info extension. On the server side in particular, this is not recommended, since it leaves the server open to certain attacks. However, this mode is necessary if you need to allow renegotiation with older client software.

conn :

a GTlsConnection

mode :

the rehandshaking mode

Since 2.28


g_tls_connection_get_rehandshake_mode ()

GTlsRehandshakeMode  g_tls_connection_get_rehandshake_mode
                                                        (GTlsConnection *conn);

Gets conn rehandshaking mode. See g_tls_connection_set_rehandshake() for details.

conn :

a GTlsConnection

Returns :

conn's rehandshaking mode

Since 2.28


g_tls_connection_set_use_system_certdb ()

void                g_tls_connection_set_use_system_certdb
                                                        (GTlsConnection *conn,
                                                         gboolean use_system_certdb);

Sets whether conn uses the system certificate database to verify peer certificates. This is TRUE by default. If set to FALSE, then peer certificate validation will always set the G_TLS_CERTIFICATE_UNKNOWN_CA error (meaning "accept-certificate" will always be emitted on client-side connections, unless that bit is not set in "validation-flags").

conn :

a GTlsConnection

use_system_certdb :

whether to use the system certificate database

Since 2.28


g_tls_connection_get_use_system_certdb ()

gboolean            g_tls_connection_get_use_system_certdb
                                                        (GTlsConnection *conn);

Gets whether conn uses the system certificate database to verify peer certificates. See g_tls_connection_set_use_system_certdb().

conn :

a GTlsConnection

Returns :

whether conn uses the system certificate database

Since 2.28


g_tls_connection_handshake ()

gboolean            g_tls_connection_handshake          (GTlsConnection *conn,
                                                         GCancellable *cancellable,
                                                         GError **error);

Attempts a TLS handshake on conn.

On the client side, it is never necessary to call this method; although the connection needs to perform a handshake after connecting (or after sending a "STARTTLS"-type command) and may need to rehandshake later if the server requests it, GTlsConnection will handle this for you automatically when you try to send or receive data on the connection. However, you can call g_tls_connection_handshake() manually if you want to know for sure whether the initial handshake succeeded or failed (as opposed to just immediately trying to write to conn's output stream, in which case if it fails, it may not be possible to tell if it failed before or after completing the handshake).

Likewise, on the server side, although a handshake is necessary at the beginning of the communication, you do not need to call this function explicitly unless you want clearer error reporting. However, you may call g_tls_connection_handshake() later on to renegotiate parameters (encryption methods, etc) with the client.

"accept_certificate" may be emitted during the handshake.

conn :

a GTlsConnection

cancellable :

a GCancellable, or NULL

error :

a GError, or NULL

Returns :

success or failure

Since 2.28


g_tls_connection_handshake_async ()

void                g_tls_connection_handshake_async    (GTlsConnection *conn,
                                                         int io_priority,
                                                         GCancellable *cancellable,
                                                         GAsyncReadyCallback callback,
                                                         gpointer user_data);

Asynchronously performs a TLS handshake on conn. See g_tls_connection_handshake() for more information.

conn :

a GTlsConnection

io_priority :

the I/O priority of the request.

cancellable :

a GCancellable, or NULL

callback :

callback to call when the handshake is complete

user_data :

the data to pass to the callback function

Since 2.28


g_tls_connection_handshake_finish ()

gboolean            g_tls_connection_handshake_finish   (GTlsConnection *conn,
                                                         GAsyncResult *result,
                                                         GError **error);

Finish an asynchronous TLS handshake operation. See g_tls_connection_handshake() for more information.

conn :

a GTlsConnection

result :

a GAsyncResult.

error :

a GError pointer, or NULL

Returns :

TRUE on success, FALSE on failure, in which case error will be set.

Since 2.28


g_tls_connection_emit_accept_certificate ()

gboolean            g_tls_connection_emit_accept_certificate
                                                        (GTlsConnection *conn,
                                                         GTlsCertificate *peer_cert,
                                                         GTlsCertificateFlags errors);

Used by GTlsConnection implementations to emit the "accept-certificate" signal.

conn :

a GTlsConnection

peer_cert :

the peer's GTlsCertificate

errors :

the problems with peer_cert

Returns :

TRUE if one of the signal handlers has returned TRUE to accept peer_cert

Since 2.28