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);
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);

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);

void                g_tls_connection_set_peer_certificate
                                                        (GTlsConnection *conn,
                                                         GTlsCertificate *certificate);
gboolean            g_tls_connection_emit_accept_certificate
                                                        (GTlsConnection *conn,
                                                         GTlsCertificate *peer_cert,
                                                         GTlsCertificateFlags errors);
GTlsCertificate *   g_tls_connection_emit_need_certificate
                                                        (GTlsConnection *conn);

Object Hierarchy

  GObject
   +----GIOStream
         +----GTlsConnection

Known Derived Interfaces

GTlsConnection is required by GTlsClientConnection and GTlsServerConnection.

Properties

  "base-io-stream"           GIOStream*            : Read / Write / Construct Only
  "certificate"              GTlsCertificate*      : Read / Write
  "peer-certificate"         GTlsCertificate*      : Read
  "rehandshake-mode"         GTlsRehandshakeMode   : Read / Write
  "require-close-notify"     gboolean              : Read / Write

Signals

  "accept-certificate"                             : Run Last
  "need-certificate"                               : Run Last

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 _GTlsConnection 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. If this is not set, "need-certificate" will be emitted during the handshake if needed.

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() or returned from one of the signals.

conn :

a GTlsConnection

Returns :

conn's certificate, or NULL

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 it has been set during the handshake.

conn :

a GTlsConnection

Returns :

conn's peer's certificate, or NULL

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 requires a proper TLS close notification before closing the connection. If this is TRUE (the default), then calling g_io_stream_close() on conn will send a TLS close notification, and likewise it will expect to receive a close notification before the connection is closed when reading, 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 it is up to the application to check that the data has been fully received.

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 requires a proper TLS close notification before closing the connection. 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_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" and "need_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_set_peer_certificate ()

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

Used by GTlsConnection implementations to set the connection's peer certificate.

conn :

a GTlsConnection

certificate :

the peer certificate

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


g_tls_connection_emit_need_certificate ()

GTlsCertificate *   g_tls_connection_emit_need_certificate
                                                        (GTlsConnection *conn);

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

conn :

a GTlsConnection

Returns :

a new GTlsCertificate

Since 2.28

Property Details

The "base-io-stream" property

  "base-io-stream"           GIOStream*            : Read / Write / Construct Only

The GIOStream that the connection wraps

Since 2.28


The "certificate" property

  "certificate"              GTlsCertificate*      : Read / Write

The connection's certificate; see g_tls_connection_set_certificate().

Since 2.28


The "peer-certificate" property

  "peer-certificate"         GTlsCertificate*      : Read

The connection's peer's certificate, after it has been set during the TLS handshake.

Since 2.28


The "rehandshake-mode" property

  "rehandshake-mode"         GTlsRehandshakeMode   : Read / Write

The rehandshaking mode. See g_tls_connection_set_rehandshake_mode().

Default value: G_TLS_REHANDSHAKE_SAFELY

Since 2.28


The "require-close-notify" property

  "require-close-notify"     gboolean              : Read / Write

Whether or not proper TLS close notification is required. See g_tls_connection_set_require_close_notify().

Default value: TRUE

Since 2.28

Signal Details

The "accept-certificate" signal

gboolean            user_function                      (GTlsConnection      *conn,
                                                        GTlsCertificate     *peer_cert,
                                                        GTlsCertificateFlags errors,
                                                        gpointer             user_data)      : Run Last

Emitted during the TLS handshake after the peer certificate has been received. You can examine peer_cert's certification path by calling g_tls_certificate_get_issuer() on it.

For a client-side connection, peer_cert is the server's certificate, and the signal will only be emitted if the certificate was not acceptable according to conn's "validation_flags". If you would like the certificate to be accepted despite errors, return TRUE from the signal handler. Otherwise, if no handler accepts the certificate, the handshake will fail with G_TLS_ERROR_BAD_CERTIFICATE.

For a server-side connection, peer_cert is the certificate presented by the client, if this was requested via the server's "authentication_mode". On the server side, the signal is always emitted when the client presents a certificate, and the certificate will only be accepted if a handler returns TRUE.

As with "need_certificate", you should not interact with the user during the signal emission if the signal was emitted as part of an asynchronous operation in the main thread.

conn :

a GTlsConnection

peer_cert :

the peer's GTlsCertificate

errors :

the problems with peer_cert.

user_data :

user data set when the signal handler was connected.

Returns :

TRUE to accept peer_cert (which will also immediately end the signal emission). FALSE to allow the signal emission to continue, which will cause the handshake to fail if no one else overrides it.

Since 2.28


The "need-certificate" signal

GTlsCertificate*    user_function                      (GTlsConnection *conn,
                                                        gpointer        user_data)      : Run Last

Emitted during the TLS handshake if a certificate is needed and one has not been set via g_tls_connection_set_certificate().

For server-side connections, a certificate is always needed, and the connection will fail if none is provided.

For client-side connections, the signal will be emitted only if the server has requested a certificate; you can call g_tls_client_connection_get_accepted_cas() to get a list of Certificate Authorities that the server will accept certificates from. If you do not return a certificate (and have not provided one via g_tls_connection_set_certificate()) then the server may reject the handshake, in which case the operation will eventually fail with G_TLS_ERROR_CERTIFICATE_REQUIRED.

Note that if this signal is emitted as part of asynchronous I/O in the main thread, then you should not attempt to interact with the user before returning from the signal handler. If you want to let the user choose a certificate to return, you would have to return NULL from the signal handler on the first attempt, and then after the connection attempt returns a G_TLS_ERROR_CERTIFICATE_REQUIRED, you can interact with the user, create a new connection, and call g_tls_connection_set_certificate() on it before handshaking (or just connect to the signal again and return the certificate the next time).

If you are doing I/O in another thread, you do not need to worry about this, and can simply block in the signal handler until the UI thread returns an answer.

conn :

a GTlsConnection

user_data :

user data set when the signal handler was connected.

Returns :

the certificate to send to the peer, or NULL to send no certificate. If you return a certificate, the signal emission will be stopped and further handlers will not be called.

Since 2.28