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/*
* Copyright (C) 2017 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/>
*
*/
#include "gnutls_int.h"
#include "errors.h"
#include "extv.h"
#include "handshake.h"
#include "tls13/certificate_request.h"
#include "ext/signature.h"
#include "mbuffers.h"
#include "algorithms.h"
#include "auth/cert.h"
typedef struct crt_req_ctx_st {
gnutls_session_t session;
gnutls_pk_algorithm_t pk_algos[MAX_ALGOS];
unsigned pk_algos_length;
uint8_t *rdn;
unsigned rdn_size;
} crt_req_ctx_st;
static unsigned is_algo_in_list(gnutls_pk_algorithm_t algo, gnutls_pk_algorithm_t *list, unsigned list_size)
{
unsigned j;
for (j=0;j<list_size;j++) {
if (list[j] == algo)
return 1;
}
return 0;
}
static
int parse_cert_extension(void *_ctx, uint16_t tls_id, const uint8_t *data, int data_size)
{
crt_req_ctx_st *ctx = _ctx;
gnutls_session_t session = ctx->session;
int ret;
/* Decide which certificate to use if the signature algorithms extension
* is present.
*/
if (tls_id == ext_mod_sig.tls_id) {
const version_entry_st *ver = get_version(session);
const gnutls_sign_entry_st *se;
/* signature algorithms; let's use it to decide the certificate to use */
unsigned i;
if (session->internals.hsk_flags & HSK_CRT_REQ_GOT_SIG_ALGO)
return gnutls_assert_val(GNUTLS_E_RECEIVED_ILLEGAL_EXTENSION);
session->internals.hsk_flags |= HSK_CRT_REQ_GOT_SIG_ALGO;
ret = _gnutls_sign_algorithm_parse_data(session, data, data_size);
if (ret < 0)
return gnutls_assert_val(ret);
/* The APIs to retrieve a client certificate accept the public
* key algorithms instead of signatures. Get the public key algorithms
* from the signatures.
*/
for (i=0;i<(unsigned)data_size;i+=2) {
se = _gnutls_tls_aid_to_sign_entry(data[i], data[i+1], ver);
if (se == NULL)
continue;
if (ctx->pk_algos_length >= sizeof(ctx->pk_algos)/sizeof(ctx->pk_algos[0]))
break;
if (is_algo_in_list(se->pk, ctx->pk_algos, ctx->pk_algos_length))
continue;
ctx->pk_algos[ctx->pk_algos_length++] = se->pk;
}
}
return 0;
}
int _gnutls13_recv_certificate_request(gnutls_session_t session)
{
int ret;
gnutls_buffer_st buf;
crt_req_ctx_st ctx;
if (unlikely(session->security_parameters.entity != GNUTLS_CLIENT))
return gnutls_assert_val(GNUTLS_E_INTERNAL_ERROR);
ret = _gnutls_recv_handshake(session, GNUTLS_HANDSHAKE_CERTIFICATE_REQUEST, 1, &buf);
if (ret < 0)
return gnutls_assert_val(ret);
/* if not received */
if (buf.length == 0) {
_gnutls_buffer_clear(&buf);
return 0;
}
_gnutls_handshake_log("HSK[%p]: parsing certificate request\n", session);
if (buf.data[0] != 0) {
/* The context field must be empty during handshake */
ret = GNUTLS_E_RECEIVED_ILLEGAL_PARAMETER;
gnutls_assert();
goto cleanup;
}
/* buf.length is positive */
buf.data++;
buf.length--;
memset(&ctx, 0, sizeof(ctx));
ctx.session = session;
ret = _gnutls_extv_parse(&ctx, parse_cert_extension, buf.data, buf.length);
if (ret < 0) {
gnutls_assert();
goto cleanup;
}
session->internals.crt_requested = 1;
ret = _gnutls_select_client_cert(session, ctx.rdn, ctx.rdn_size,
ctx.pk_algos, ctx.pk_algos_length);
if (ret < 0) {
gnutls_assert();
goto cleanup;
}
session->internals.hsk_flags |= HSK_CRT_ASKED;
ret = 0;
cleanup:
_gnutls_buffer_clear(&buf);
gnutls_free(ctx.rdn);
return ret;
}
int _gnutls13_send_certificate_request(gnutls_session_t session, unsigned again)
{
gnutls_certificate_credentials_t cred;
int ret;
mbuffer_st *bufel = NULL;
gnutls_buffer_st buf;
unsigned init_pos;
if (again == 0) {
if (session->internals.send_cert_req == 0)
return 0;
cred = (gnutls_certificate_credentials_t)
_gnutls_get_cred(session, GNUTLS_CRD_CERTIFICATE);
if (cred == NULL)
return gnutls_assert_val(GNUTLS_E_INSUFFICIENT_CREDENTIALS);
ret = _gnutls_buffer_init_handshake_mbuffer(&buf);
if (ret < 0)
return gnutls_assert_val(ret);
ret = _gnutls_buffer_append_prefix(&buf, 8, 0);
if (ret < 0) {
gnutls_assert();
goto cleanup;
}
ret = _gnutls_extv_append_init(&buf);
if (ret < 0) {
gnutls_assert();
goto cleanup;
}
init_pos = ret;
ret = _gnutls_extv_append(&buf, ext_mod_sig.tls_id, session,
(extv_append_func)_gnutls_sign_algorithm_write_params);
if (ret < 0) {
gnutls_assert();
goto cleanup;
}
ret = _gnutls_extv_append_final(&buf, init_pos);
if (ret < 0) {
gnutls_assert();
goto cleanup;
}
bufel = _gnutls_buffer_to_mbuffer(&buf);
session->internals.hsk_flags |= HSK_CRT_REQ_SENT;
}
return _gnutls_send_handshake(session, bufel, GNUTLS_HANDSHAKE_CERTIFICATE_REQUEST);
cleanup:
_gnutls_buffer_clear(&buf);
return ret;
}
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