GTlsClientConnection: GIO Reference Manual

## GTlsClientConnection GTlsClientConnection — TLS client-side connection |

## Functions

GIOStream * | g_tls_client_connection_new ()
void | g_tls_client_connection_set_server_identity ()
GSocketConnectable * | g_tls_client_connection_get_server_identity ()
void | g_tls_client_connection_set_validation_flags ()
GTlsCertificateFlags | g_tls_client_connection_get_validation_flags ()
void | g_tls_client_connection_set_use_ssl3 ()
gboolean | g_tls_client_connection_get_use_ssl3 ()
GList * | g_tls_client_connection_get_accepted_cas ()
void | g_tls_client_connection_copy_session_state ()

## Properties

gpointer | accepted-cas | Read
GSocketConnectable * | server-identity | Read / Write / Construct
gboolean | use-ssl3 | Read / Write / Construct
GTlsCertificateFlags | validation-flags | Read / Write / Construct

## Types and Values

| GTlsClientConnection
struct | GTlsClientConnectionInterface

## Object Hierarchy

        GInterface
        ╰── GTlsClientConnection

## Prerequisites

GTlsClientConnection requires GTlsConnection.

## Includes

    #include <gio/gio.h>

## Description

GTlsClientConnection is the client-side subclass of GTlsConnection, representing a client-side TLS connection.

## Functions

### g_tls_client_connection_new ()

    GIOStream *
    g_tls_client_connection_new (GIOStream *base_io_stream,
                                 GSocketConnectable *server_identity,
                                 GError **error);

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 “base-io-stream” for restrictions on when application code can run operations on the `base_io_stream` after this function has returned.

#### Parameters

base_io_stream | the GIOStream to wrap |
server_identity | the expected identity of the server. | [nullable]
error | GError for error reporting, or `NULL` to ignore. |

#### Returns

the new GTlsClientConnection, or `NULL` on error.

[transfer full][type GTlsClientConnection]

Since: 2.28

### g_tls_client_connection_set_server_identity ()

    void
    g_tls_client_connection_set_server_identity
                                   (GTlsClientConnection *conn,
                                    GSocketConnectable *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.

#### Parameters

conn | the GTlsClientConnection |
identity | a GSocketConnectable describing the expected server identity |

Since: 2.28

### g_tls_client_connection_get_server_identity ()

    GSocketConnectable *
    g_tls_client_connection_get_server_identity
                                   (GTlsClientConnection *conn);

Gets `conn` 's expected server identity

#### Parameters

conn | the GTlsClientConnection |

#### Returns

a GSocketConnectable describing the expected server identity, or `NULL` if the expected identity is not known.

[nullable][transfer none]

Since: 2.28

### g_tls_client_connection_set_validation_flags ()

    void
    g_tls_client_connection_set_validation_flags
                                   (GTlsClientConnection *conn,
                                    GTlsCertificateFlags flags);

`g_tls_client_connection_set_validation_flags` has been deprecated since version 2.72 and should not be used in newly-written code.

Do not attempt to ignore validation errors.

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 “validation-flags” for more information.

#### Parameters

conn | the GTlsClientConnection |
flags | the GTlsCertificateFlags to use |

Since: 2.28

### g_tls_client_connection_get_validation_flags ()

    GTlsCertificateFlags
    g_tls_client_connection_get_validation_flags
                                   (GTlsClientConnection *conn);

`g_tls_client_connection_get_validation_flags` has been deprecated since version 2.72 and should not be used in newly-written code.

Do not attempt to ignore validation errors.

Gets `conn` 's validation flags

This function does not work as originally designed and is impossible to use correctly. See “validation-flags” for more information.

#### Parameters

conn | the GTlsClientConnection |

#### Returns

the validation flags

Since: 2.28

### g_tls_client_connection_set_use_ssl3 ()

    void
    g_tls_client_connection_set_use_ssl3 (GTlsClientConnection *conn,
                                          gboolean use_ssl3);

`g_tls_client_connection_set_use_ssl3` has been deprecated since version 2.56 and should not be used in newly-written code.

SSL 3.0 is insecure.

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.

#### Parameters

conn | the GTlsClientConnection |
use_ssl3 | a gboolean, ignored |

Since: 2.28

### g_tls_client_connection_get_use_ssl3 ()

    gboolean
    g_tls_client_connection_get_use_ssl3 (GTlsClientConnection *conn);

`g_tls_client_connection_get_use_ssl3` has been deprecated since version 2.56 and should not be used in newly-written code.

SSL 3.0 is insecure.

SSL 3.0 is no longer supported. See `g_tls_client_connection_set_use_ssl3()` for details.

#### Parameters

conn | the GTlsClientConnection |

#### Returns

`FALSE`

Since: 2.28

### g_tls_client_connection_get_accepted_cas ()

    GList *
    g_tls_client_connection_get_accepted_cas
                                   (GTlsClientConnection *conn);

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.

#### Parameters

conn | the GTlsClientConnection |

#### Returns

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()`.

[element-type GByteArray][transfer full]

Since: 2.28

### g_tls_client_connection_copy_session_state ()

    void
    g_tls_client_connection_copy_session_state
                                   (GTlsClientConnection *conn,
                                    GTlsClientConnection *source);

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.

#### Parameters

conn | a GTlsClientConnection |
source | a GTlsClientConnection |

Since: 2.46

## Types and Values

### GTlsClientConnection

    typedef struct _GTlsClientConnection GTlsClientConnection;

Abstract base class for the backend-specific client connection type.

Since: 2.28

### struct GTlsClientConnectionInterface

    struct GTlsClientConnectionInterface {
      GTypeInterface g_iface;

      void     ( *copy_session_state )     (GTlsClientConnection       *conn,
                                            GTlsClientConnection       *source);
    };

vtable for a GTlsClientConnection implementation.

#### Members

`copy_session_state` () | Copies session state from one GTlsClientConnection to another. |

Since: 2.26

## Property Details

### The `“accepted-cas”` property

      “accepted-cas”             gpointer

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.

[element-type GLib.ByteArray]

Owner: GTlsClientConnection

Flags: Read

Since: 2.28

### The `“server-identity”` property

      “server-identity”          GSocketConnectable *

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 “validation-flags”, this object will be used to determine the expected identify of the remote end of the connection; if “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.

Owner: GTlsClientConnection

Flags: Read / Write / Construct

Since: 2.28

### The `“use-ssl3”` property

      “use-ssl3”                 gboolean

SSL 3.0 is no longer supported. See `g_tls_client_connection_set_use_ssl3()` for details.

`GTlsClientConnection:use-ssl3` has been deprecated since version 2.56 and should not be used in newly-written code.

SSL 3.0 is insecure.

Owner: GTlsClientConnection

Flags: Read / Write / Construct

Default value: FALSE

Since: 2.28

### The `“validation-flags”` property

      “validation-flags”         GTlsCertificateFlags

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 “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 “accept-certificate”.

`GTlsClientConnection:validation-flags` has been deprecated since version 2.72 and should not be used in newly-written code.

Do not attempt to ignore validation errors.

Owner: GTlsClientConnection

Flags: Read / Write / Construct

Default value: G_TLS_CERTIFICATE_UNKNOWN_CA | G_TLS_CERTIFICATE_BAD_IDENTITY | G_TLS_CERTIFICATE_NOT_ACTIVATED | G_TLS_CERTIFICATE_EXPIRED | G_TLS_CERTIFICATE_REVOKED | G_TLS_CERTIFICATE_INSECURE | G_TLS_CERTIFICATE_GENERIC_ERROR

Since: 2.28