/*
* Copyright (C) 2013 Nikos Mavrogiannopoulos
* Copyright (C) 2017 Red Hat, Inc.
*
* This file is part of GnuTLS.
*
* The GnuTLS 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 program. If not, see <https://www.gnu.org/licenses/>
*
*/
#include "gnutls_int.h"
#include "auth.h"
#include "errors.h"
#include "num.h"
#include <ext/alpn.h>
static int _gnutls_alpn_recv_params(gnutls_session_t session,
const uint8_t * data,
size_t data_size);
static int _gnutls_alpn_send_params(gnutls_session_t session,
gnutls_buffer_st * extdata);
static void _gnutls_alpn_deinit_data(gnutls_ext_priv_data_t priv);
const hello_ext_entry_st ext_mod_alpn = {
.name = "ALPN",
.tls_id = 16,
.gid = GNUTLS_EXTENSION_ALPN,
/* this extension must be parsed even on resumption */
.client_parse_point = GNUTLS_EXT_MANDATORY,
.server_parse_point = GNUTLS_EXT_MANDATORY,
.validity = GNUTLS_EXT_FLAG_TLS | GNUTLS_EXT_FLAG_DTLS |
GNUTLS_EXT_FLAG_CLIENT_HELLO | GNUTLS_EXT_FLAG_EE |
GNUTLS_EXT_FLAG_TLS12_SERVER_HELLO,
.recv_func = _gnutls_alpn_recv_params,
.send_func = _gnutls_alpn_send_params,
.deinit_func = _gnutls_alpn_deinit_data,
.cannot_be_overriden = 1
};
static int
_gnutls_alpn_recv_params(gnutls_session_t session,
const uint8_t * data, size_t data_size)
{
unsigned int i;
int ret;
const uint8_t *p = data;
unsigned len1, len;
alpn_ext_st *priv;
gnutls_ext_priv_data_t epriv;
int selected_protocol_index;
ret =
_gnutls_hello_ext_get_priv(session, GNUTLS_EXTENSION_ALPN,
&epriv);
if (ret < 0)
return 0;
priv = epriv;
DECR_LENGTH_RET(data_size, 2, GNUTLS_E_UNEXPECTED_PACKET_LENGTH);
len = _gnutls_read_uint16(p);
p += 2;
if (len == 0 || len > (size_t)data_size)
return
gnutls_assert_val(GNUTLS_E_UNEXPECTED_PACKET_LENGTH);
if (session->security_parameters.entity == GNUTLS_SERVER) {
selected_protocol_index = MAX_ALPN_PROTOCOLS+1;
while (data_size > 0) {
DECR_LENGTH_RET(data_size, 1, GNUTLS_E_UNEXPECTED_PACKET_LENGTH);
len1 = *p;
p += 1;
DECR_LENGTH_RET(data_size, len1, GNUTLS_E_UNEXPECTED_PACKET_LENGTH);
if (len1 == 0)
return gnutls_assert_val(GNUTLS_E_UNEXPECTED_PACKET_LENGTH);
for (i = 0; i < priv->size; i++) {
if (priv->protocol_size[i] == len1
&& memcmp(p, priv->protocols[i],
len1) == 0) {
if (priv->flags & GNUTLS_ALPN_SERVER_PRECEDENCE) {
if (selected_protocol_index > (int)i) {
selected_protocol_index = i;
priv->selected_protocol =
priv->protocols[i];
priv->selected_protocol_size =
priv->protocol_size[i];
break;
}
} else {
priv->selected_protocol =
priv->protocols[i];
priv->selected_protocol_size =
priv->protocol_size[i];
return 0;
}
}
}
p += len1;
}
} else {
DECR_LENGTH_RET(data_size, 1, GNUTLS_E_UNEXPECTED_PACKET_LENGTH);
len1 = *p;
p += 1;
DECR_LENGTH_RET(data_size, len1, GNUTLS_E_UNEXPECTED_PACKET_LENGTH);
for (i = 0; i < priv->size; i++) {
if (priv->protocol_size[i] == len1
&& memcmp(p, priv->protocols[i], len1) == 0) {
priv->selected_protocol =
priv->protocols[i];
priv->selected_protocol_size =
priv->protocol_size[i];
break;
}
}
/*p += len1;*/
}
if (priv->selected_protocol == NULL
&& (priv->flags & GNUTLS_ALPN_MAND))
return gnutls_assert_val(GNUTLS_E_NO_APPLICATION_PROTOCOL);
return 0;
}
static int
_gnutls_alpn_send_params(gnutls_session_t session,
gnutls_buffer_st * extdata)
{
unsigned i;
int total_size = 0, ret;
alpn_ext_st *priv;
gnutls_ext_priv_data_t epriv;
ret =
_gnutls_hello_ext_get_priv(session, GNUTLS_EXTENSION_ALPN,
&epriv);
if (ret < 0)
return 0;
priv = epriv;
if (priv->size == 0)
return 0;
if (session->security_parameters.entity == GNUTLS_SERVER) {
if (priv->selected_protocol_size == 0)
return 0;
ret =
_gnutls_buffer_append_prefix(extdata, 16,
priv->
selected_protocol_size +
1);
if (ret < 0)
return gnutls_assert_val(ret);
total_size += 2;
ret =
_gnutls_buffer_append_data_prefix(extdata, 8,
priv->
selected_protocol,
priv->
selected_protocol_size);
if (ret < 0)
return gnutls_assert_val(ret);
total_size += 1 + priv->selected_protocol_size;
} else {
int t = 0;
for (i = 0; i < priv->size; i++)
t += priv->protocol_size[i] + 1;
ret = _gnutls_buffer_append_prefix(extdata, 16, t);
if (ret < 0)
return gnutls_assert_val(ret);
total_size += 2;
for (i = 0; i < priv->size; i++) {
ret =
_gnutls_buffer_append_data_prefix(extdata, 8,
priv->
protocols[i],
priv->
protocol_size
[i]);
if (ret < 0)
return gnutls_assert_val(ret);
total_size += 1 + priv->protocol_size[i];
}
}
return total_size;
}
/**
* gnutls_alpn_get_selected_protocol:
* @session: is a #gnutls_session_t type.
* @protocol: will hold the protocol name
*
* This function allows you to get the negotiated protocol name. The
* returned protocol should be treated as opaque, constant value and
* only valid during the session life.
*
* The selected protocol is the first supported by the list sent
* by the client.
*
* Returns: On success, %GNUTLS_E_SUCCESS (0) is returned,
* otherwise a negative error code is returned.
*
* Since 3.2.0
**/
int
gnutls_alpn_get_selected_protocol(gnutls_session_t session,
gnutls_datum_t * protocol)
{
alpn_ext_st *priv;
int ret;
gnutls_ext_priv_data_t epriv;
ret =
_gnutls_hello_ext_get_priv(session, GNUTLS_EXTENSION_ALPN,
&epriv);
if (ret < 0) {
gnutls_assert();
return GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE;
}
priv = epriv;
if (priv->selected_protocol_size == 0)
return
gnutls_assert_val
(GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE);
protocol->data = priv->selected_protocol;
protocol->size = priv->selected_protocol_size;
return 0;
}
/**
* gnutls_alpn_set_protocols:
* @session: is a #gnutls_session_t type.
* @protocols: is the protocol names to add.
* @protocols_size: the number of protocols to add.
* @flags: zero or a sequence of %gnutls_alpn_flags_t
*
* This function is to be used by both clients and servers, to declare
* the supported ALPN protocols, which are used during negotiation with peer.
*
* See %gnutls_alpn_flags_t description for the documentation of available
* flags.
*
* Returns: On success, %GNUTLS_E_SUCCESS (0) is returned,
* otherwise a negative error code is returned.
*
* Since 3.2.0
**/
int
gnutls_alpn_set_protocols(gnutls_session_t session,
const gnutls_datum_t * protocols,
unsigned protocols_size, unsigned int flags)
{
int ret;
alpn_ext_st *priv;
gnutls_ext_priv_data_t epriv;
unsigned i;
ret =
_gnutls_hello_ext_get_priv(session, GNUTLS_EXTENSION_ALPN,
&epriv);
if (ret < 0) {
priv = gnutls_calloc(1, sizeof(*priv));
if (priv == NULL) {
gnutls_assert();
return GNUTLS_E_MEMORY_ERROR;
}
epriv = priv;
_gnutls_hello_ext_set_priv(session,
GNUTLS_EXTENSION_ALPN, epriv);
} else
priv = epriv;
if (protocols_size > MAX_ALPN_PROTOCOLS)
return gnutls_assert_val(GNUTLS_E_INVALID_REQUEST);
for (i = 0; i < protocols_size; i++) {
if (protocols[i].size >= MAX_ALPN_PROTOCOL_NAME)
return gnutls_assert_val(GNUTLS_E_INVALID_REQUEST);
memcpy(priv->protocols[i], protocols[i].data,
protocols[i].size);
priv->protocol_size[i] = protocols[i].size;
priv->size++;
}
priv->flags = flags;
return 0;
}
static void _gnutls_alpn_deinit_data(gnutls_ext_priv_data_t priv)
{
gnutls_free(priv);
}