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/*
* Copyright (C) 2002-2016 Free Software Foundation, Inc.
* Copyright (C) 2015-2016 Red Hat, Inc.
*
* Author: Nikos Mavrogiannopoulos
*
* 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 <http://www.gnu.org/licenses/>
*
*/
/* This file contains the code the Certificate Type TLS extension.
* This extension is currently gnutls specific.
*/
#include "gnutls_int.h"
#include "errors.h"
#include "num.h"
#include <gnutls/gnutls.h>
#include <ext/signature.h>
#include <state.h>
#include <num.h>
#include <algorithms.h>
#include <abstract_int.h>
static int _gnutls_signature_algorithm_recv_params(gnutls_session_t
session,
const uint8_t * data,
size_t data_size);
static int _gnutls_signature_algorithm_send_params(gnutls_session_t
session,
gnutls_buffer_st *
extdata);
static void signature_algorithms_deinit_data(extension_priv_data_t priv);
static int signature_algorithms_pack(extension_priv_data_t epriv,
gnutls_buffer_st * ps);
static int signature_algorithms_unpack(gnutls_buffer_st * ps,
extension_priv_data_t * _priv);
const extension_entry_st ext_mod_sig = {
.name = "Signature Algorithms",
.type = GNUTLS_EXTENSION_SIGNATURE_ALGORITHMS,
.parse_type = GNUTLS_EXT_TLS,
.recv_func = _gnutls_signature_algorithm_recv_params,
.send_func = _gnutls_signature_algorithm_send_params,
.pack_func = signature_algorithms_pack,
.unpack_func = signature_algorithms_unpack,
.deinit_func = signature_algorithms_deinit_data,
};
typedef struct {
/* TLS 1.2 signature algorithms */
gnutls_sign_algorithm_t sign_algorithms[MAX_SIGNATURE_ALGORITHMS];
uint16_t sign_algorithms_size;
} sig_ext_st;
/* generates a SignatureAndHashAlgorithm structure with length as prefix
* by using the setup priorities.
*/
int
_gnutls_sign_algorithm_write_params(gnutls_session_t session,
uint8_t * data, size_t max_data_size)
{
uint8_t *p = data, *len_p;
unsigned int len, i, j;
const sign_algorithm_st *aid;
if (max_data_size <
(session->internals.priorities.sign_algo.algorithms * 2) + 2) {
gnutls_assert();
return GNUTLS_E_SHORT_MEMORY_BUFFER;
}
len = 0;
len_p = p;
p += 2;
for (i = j = 0;
j < session->internals.priorities.sign_algo.algorithms;
i += 2, j++) {
aid =
_gnutls_sign_to_tls_aid(session->internals.
priorities.sign_algo.
priority[j]);
if (aid == NULL)
continue;
_gnutls_handshake_log
("EXT[%p]: sent signature algo (%d.%d) %s\n", session,
aid->hash_algorithm, aid->sign_algorithm,
gnutls_sign_get_name(session->internals.priorities.
sign_algo.priority[j]));
*p = aid->hash_algorithm;
p++;
*p = aid->sign_algorithm;
p++;
len += 2;
}
_gnutls_write_uint16(len, len_p);
return len + 2;
}
/* Parses the Signature Algorithm structure and stores data into
* session->security_parameters.extensions.
*/
int
_gnutls_sign_algorithm_parse_data(gnutls_session_t session,
const uint8_t * data, size_t data_size)
{
unsigned int sig, i;
sig_ext_st *priv;
extension_priv_data_t epriv;
if (data_size == 0 || data_size % 2 != 0)
return gnutls_assert_val(GNUTLS_E_UNEXPECTED_PACKET_LENGTH);
priv = gnutls_calloc(1, sizeof(*priv));
if (priv == NULL) {
gnutls_assert();
return GNUTLS_E_MEMORY_ERROR;
}
for (i = 0; i < data_size; i += 2) {
sign_algorithm_st aid;
aid.hash_algorithm = data[i];
aid.sign_algorithm = data[i + 1];
sig = _gnutls_tls_aid_to_sign(&aid);
_gnutls_handshake_log
("EXT[%p]: rcvd signature algo (%d.%d) %s\n", session,
aid.hash_algorithm, aid.sign_algorithm,
gnutls_sign_get_name(sig));
if (sig != GNUTLS_SIGN_UNKNOWN) {
if (priv->sign_algorithms_size ==
MAX_SIGNATURE_ALGORITHMS)
break;
priv->sign_algorithms[priv->
sign_algorithms_size++] =
sig;
}
}
epriv = priv;
_gnutls_ext_set_session_data(session,
GNUTLS_EXTENSION_SIGNATURE_ALGORITHMS,
epriv);
return 0;
}
/*
* In case of a server: if a SIGNATURE_ALGORITHMS extension type is
* received then it stores into the session security parameters the
* new value.
*
* In case of a client: If a signature_algorithms have been specified
* then it is an error;
*/
static int
_gnutls_signature_algorithm_recv_params(gnutls_session_t session,
const uint8_t * data,
size_t _data_size)
{
ssize_t data_size = _data_size;
int ret;
if (session->security_parameters.entity == GNUTLS_CLIENT) {
/* nothing for now */
gnutls_assert();
/* Although TLS 1.2 mandates that we must not accept reply
* to this message, there are good reasons to just ignore it. Check
* http://www.ietf.org/mail-archive/web/tls/current/msg03880.html
*/
/* return GNUTLS_E_UNEXPECTED_PACKET; */
} else {
/* SERVER SIDE - we must check if the sent cert type is the right one
*/
if (data_size >= 2) {
uint16_t len;
DECR_LEN(data_size, 2);
len = _gnutls_read_uint16(data);
DECR_LEN(data_size, len);
if (data_size > 0)
return gnutls_assert_val(GNUTLS_E_UNEXPECTED_PACKET_LENGTH);
ret =
_gnutls_sign_algorithm_parse_data(session,
data + 2,
len);
if (ret < 0) {
gnutls_assert();
return ret;
}
} else {
return gnutls_assert_val(GNUTLS_E_UNEXPECTED_PACKET_LENGTH);
}
}
return 0;
}
/* returns data_size or a negative number on failure
*/
static int
_gnutls_signature_algorithm_send_params(gnutls_session_t session,
gnutls_buffer_st * extdata)
{
int ret;
size_t init_length = extdata->length;
const version_entry_st *ver = get_version(session);
if (unlikely(ver == NULL))
return gnutls_assert_val(GNUTLS_E_INTERNAL_ERROR);
/* this function sends the client extension data */
if (session->security_parameters.entity == GNUTLS_CLIENT
&& _gnutls_version_has_selectable_sighash(ver)) {
if (session->internals.priorities.sign_algo.algorithms > 0) {
uint8_t p[MAX_SIGN_ALGO_SIZE];
ret =
_gnutls_sign_algorithm_write_params(session, p,
sizeof(p));
if (ret < 0)
return gnutls_assert_val(ret);
ret = _gnutls_buffer_append_data(extdata, p, ret);
if (ret < 0)
return gnutls_assert_val(ret);
return extdata->length - init_length;
}
}
/* if we are here it means we don't send the extension */
return 0;
}
/* Returns a requested by the peer signature algorithm that
* matches the given certificate's public key algorithm.
*
* When the @client_cert flag is not set, then this function will
* also check whether the signature algorithm is allowed to be
* used in that session. Otherwise GNUTLS_SIGN_UNKNOWN is
* returned.
*/
gnutls_sign_algorithm_t
_gnutls_session_get_sign_algo(gnutls_session_t session,
gnutls_pcert_st * cert, unsigned client_cert)
{
unsigned i;
int ret;
const version_entry_st *ver = get_version(session);
sig_ext_st *priv;
extension_priv_data_t epriv;
unsigned int cert_algo;
if (unlikely(ver == NULL))
return gnutls_assert_val(GNUTLS_SIGN_UNKNOWN);
cert_algo = gnutls_pubkey_get_pk_algorithm(cert->pubkey, NULL);
ret =
_gnutls_ext_get_session_data(session,
GNUTLS_EXTENSION_SIGNATURE_ALGORITHMS,
&epriv);
priv = epriv;
if (ret < 0 || !_gnutls_version_has_selectable_sighash(ver)) {
/* none set, allow SHA-1 only */
ret = gnutls_pk_to_sign(cert_algo, GNUTLS_DIG_SHA1);
if (!client_cert && _gnutls_session_sign_algo_enabled(session, ret) < 0)
goto fail;
return ret;
}
for (i = 0; i < priv->sign_algorithms_size; i++) {
if (gnutls_sign_supports_pk_algorithm(priv->sign_algorithms[i], cert_algo) != 0) {
if (_gnutls_pubkey_compatible_with_sig
(session, cert->pubkey, ver,
priv->sign_algorithms[i]) < 0)
continue;
if (!client_cert && _gnutls_session_sign_algo_enabled
(session, priv->sign_algorithms[i]) < 0)
continue;
return priv->sign_algorithms[i];
}
}
fail:
return GNUTLS_SIGN_UNKNOWN;
}
/* Check if the given signature algorithm is supported.
* This means that it is enabled by the priority functions,
* and in case of a server a matching certificate exists.
*/
int
_gnutls_session_sign_algo_enabled(gnutls_session_t session,
gnutls_sign_algorithm_t sig)
{
unsigned i;
const version_entry_st *ver = get_version(session);
if (unlikely(ver == NULL))
return gnutls_assert_val(GNUTLS_E_INTERNAL_ERROR);
if (!_gnutls_version_has_selectable_sighash(ver)) {
return 0;
}
for (i = 0; i < session->internals.priorities.sign_algo.algorithms;
i++) {
if (session->internals.priorities.sign_algo.priority[i] ==
sig) {
return 0; /* ok */
}
}
return GNUTLS_E_UNSUPPORTED_SIGNATURE_ALGORITHM;
}
static void signature_algorithms_deinit_data(extension_priv_data_t priv)
{
gnutls_free(priv);
}
static int
signature_algorithms_pack(extension_priv_data_t epriv,
gnutls_buffer_st * ps)
{
sig_ext_st *priv = epriv;
int ret, i;
BUFFER_APPEND_NUM(ps, priv->sign_algorithms_size);
for (i = 0; i < priv->sign_algorithms_size; i++) {
BUFFER_APPEND_NUM(ps, priv->sign_algorithms[i]);
}
return 0;
}
static int
signature_algorithms_unpack(gnutls_buffer_st * ps,
extension_priv_data_t * _priv)
{
sig_ext_st *priv;
int i, ret;
extension_priv_data_t epriv;
priv = gnutls_calloc(1, sizeof(*priv));
if (priv == NULL) {
gnutls_assert();
return GNUTLS_E_MEMORY_ERROR;
}
BUFFER_POP_NUM(ps, priv->sign_algorithms_size);
for (i = 0; i < priv->sign_algorithms_size; i++) {
BUFFER_POP_NUM(ps, priv->sign_algorithms[i]);
}
epriv = priv;
*_priv = epriv;
return 0;
error:
gnutls_free(priv);
return ret;
}
/**
* gnutls_sign_algorithm_get_requested:
* @session: is a #gnutls_session_t type.
* @indx: is an index of the signature algorithm to return
* @algo: the returned certificate type will be stored there
*
* Returns the signature algorithm specified by index that was
* requested by the peer. If the specified index has no data available
* this function returns %GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE. If
* the negotiated TLS version does not support signature algorithms
* then %GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE will be returned even
* for the first index. The first index is 0.
*
* This function is useful in the certificate callback functions
* to assist in selecting the correct certificate.
*
* Returns: On success, %GNUTLS_E_SUCCESS (0) is returned, otherwise
* an error code is returned.
*
* Since: 2.10.0
**/
int
gnutls_sign_algorithm_get_requested(gnutls_session_t session,
size_t indx,
gnutls_sign_algorithm_t * algo)
{
const version_entry_st *ver = get_version(session);
sig_ext_st *priv;
extension_priv_data_t epriv;
int ret;
if (unlikely(ver == NULL))
return gnutls_assert_val(GNUTLS_E_INTERNAL_ERROR);
ret =
_gnutls_ext_get_session_data(session,
GNUTLS_EXTENSION_SIGNATURE_ALGORITHMS,
&epriv);
if (ret < 0) {
gnutls_assert();
return ret;
}
priv = epriv;
if (!_gnutls_version_has_selectable_sighash(ver)
|| priv->sign_algorithms_size == 0) {
return GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE;
}
if (indx < priv->sign_algorithms_size) {
*algo = priv->sign_algorithms[indx];
return 0;
} else
return GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE;
}
/**
* gnutls_sign_algorithm_get:
* @session: is a #gnutls_session_t type.
*
* Returns the signature algorithm that is (or will be) used in this
* session by the server to sign data. This function should be
* used only with TLS 1.2 or later.
*
* Returns: The sign algorithm or %GNUTLS_SIGN_UNKNOWN.
*
* Since: 3.1.1
**/
int gnutls_sign_algorithm_get(gnutls_session_t session)
{
return session->security_parameters.server_sign_algo;
}
/**
* gnutls_sign_algorithm_get_client:
* @session: is a #gnutls_session_t type.
*
* Returns the signature algorithm that is (or will be) used in this
* session by the client to sign data. This function should be
* used only with TLS 1.2 or later.
*
* Returns: The sign algorithm or %GNUTLS_SIGN_UNKNOWN.
*
* Since: 3.1.11
**/
int gnutls_sign_algorithm_get_client(gnutls_session_t session)
{
return session->security_parameters.client_sign_algo;
}
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