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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 <https://www.gnu.org/licenses/>
*
*/
#include "gnutls_int.h"
#include "errors.h"
#include "handshake.h"
#include "auth/cert.h"
#include "ext/signature.h"
#include "algorithms.h"
#include "tls13-sig.h"
#include "mbuffers.h"
#include "tls13/certificate_verify.h"
#define SRV_CTX "TLS 1.3, server CertificateVerify"
static const gnutls_datum_t srv_ctx = {
(void*)SRV_CTX, sizeof(SRV_CTX)-1
};
#define CLI_CTX "TLS 1.3, client CertificateVerify"
static const gnutls_datum_t cli_ctx = {
(void*)CLI_CTX, sizeof(CLI_CTX)-1
};
int _gnutls13_recv_certificate_verify(gnutls_session_t session)
{
int ret;
gnutls_buffer_st buf;
const gnutls_sign_entry_st *se;
gnutls_datum_t sig_data;
gnutls_certificate_credentials_t cred;
unsigned vflags;
gnutls_pcert_st peer_cert;
cert_auth_info_t info = _gnutls_get_auth_info(session, GNUTLS_CRD_CERTIFICATE);
bool server = 0;
gnutls_certificate_type_t cert_type;
memset(&peer_cert, 0, sizeof(peer_cert));
/* this message is only expected if we have received
* a certificate message */
if (!(session->internals.hsk_flags & HSK_CRT_VRFY_EXPECTED))
return 0;
if (session->security_parameters.entity == GNUTLS_SERVER)
server = 1;
cred = (gnutls_certificate_credentials_t)
_gnutls_get_cred(session, GNUTLS_CRD_CERTIFICATE);
if (unlikely(cred == NULL))
return gnutls_assert_val(GNUTLS_E_INSUFFICIENT_CREDENTIALS);
if (unlikely(info == NULL))
return gnutls_assert_val(GNUTLS_E_INTERNAL_ERROR);
ret = _gnutls_recv_handshake(session, GNUTLS_HANDSHAKE_CERTIFICATE_VERIFY, 0, &buf);
if (ret < 0)
return gnutls_assert_val(ret);
_gnutls_handshake_log("HSK[%p]: Parsing certificate verify\n", session);
if (buf.length < 2) {
gnutls_assert();
ret = GNUTLS_E_UNEXPECTED_PACKET_LENGTH;
goto cleanup;
}
se = _gnutls_tls_aid_to_sign_entry(buf.data[0], buf.data[1], get_version(session));
if (se == NULL) {
_gnutls_handshake_log("Found unsupported signature (%d.%d)\n", (int)buf.data[0], (int)buf.data[1]);
ret = gnutls_assert_val(GNUTLS_E_RECEIVED_ILLEGAL_PARAMETER);
goto cleanup;
}
if (server)
gnutls_sign_algorithm_set_client(session, se->id);
else
gnutls_sign_algorithm_set_server(session, se->id);
buf.data+=2;
buf.length-=2;
/* we check during verification whether the algorithm is enabled */
ret = _gnutls_buffer_pop_datum_prefix16(&buf, &sig_data);
if (ret < 0) {
gnutls_assert();
goto cleanup;
}
if (sig_data.size == 0) {
gnutls_assert();
ret = GNUTLS_E_RECEIVED_ILLEGAL_PARAMETER;
goto cleanup;
}
/* We verify the certificate of the peer. Therefore we need to
* retrieve the negotiated certificate type for the peer. */
cert_type = get_certificate_type(session, GNUTLS_CTYPE_PEERS);
/* Verify the signature */
ret = _gnutls_get_auth_info_pcert(&peer_cert, cert_type, info);
if (ret < 0) {
gnutls_assert();
goto cleanup;
}
vflags = cred->verify_flags | session->internals.additional_verify_flags;
ret = _gnutls13_handshake_verify_data(session, vflags, &peer_cert,
server?(&cli_ctx):(&srv_ctx),
&sig_data, se);
if (ret < 0) {
gnutls_assert();
goto cleanup;
}
if (buf.length > 0) {
gnutls_assert();
ret = GNUTLS_E_UNEXPECTED_PACKET_LENGTH;
goto cleanup;
}
ret = 0;
cleanup:
gnutls_pcert_deinit(&peer_cert);
_gnutls_buffer_clear(&buf);
return ret;
}
int _gnutls13_send_certificate_verify(gnutls_session_t session, unsigned again)
{
int ret;
gnutls_pcert_st *apr_cert_list;
gnutls_privkey_t apr_pkey;
int apr_cert_list_length;
mbuffer_st *bufel = NULL;
gnutls_buffer_st buf;
gnutls_datum_t sig = {NULL, 0};
gnutls_sign_algorithm_t algo;
const gnutls_sign_entry_st *se;
bool server = 0;
if (again == 0) {
if (!session->internals.initial_negotiation_completed &&
session->internals.hsk_flags & HSK_PSK_SELECTED)
return 0;
if (session->security_parameters.entity == GNUTLS_SERVER &&
session->internals.resumed)
return 0;
if (session->security_parameters.entity == GNUTLS_SERVER)
server = 1;
ret = _gnutls_get_selected_cert(session, &apr_cert_list,
&apr_cert_list_length, &apr_pkey);
if (ret < 0)
return gnutls_assert_val(ret);
if (apr_cert_list_length == 0) {
if (server) {
return gnutls_assert_val(GNUTLS_E_INSUFFICIENT_CREDENTIALS);
} else {
/* for client, this means either we
* didn't get a cert request or we are
* declining authentication; in either
* case we don't send a cert verify */
return 0;
}
}
if (server) {
algo = _gnutls_session_get_sign_algo(session, &apr_cert_list[0], apr_pkey, 0);
if (algo == GNUTLS_SIGN_UNKNOWN)
return gnutls_assert_val(GNUTLS_E_INCOMPATIBLE_SIG_WITH_KEY);
gnutls_sign_algorithm_set_server(session, algo);
} else {
/* for client, signature algorithm is already
* determined from Certificate Request */
algo = gnutls_sign_algorithm_get_client(session);
if (unlikely(algo == GNUTLS_SIGN_UNKNOWN))
return gnutls_assert_val(GNUTLS_E_INTERNAL_ERROR);
}
se = _gnutls_sign_to_entry(algo);
ret = _gnutls13_handshake_sign_data(session, &apr_cert_list[0], apr_pkey,
server?(&srv_ctx):(&cli_ctx),
&sig, se);
if (ret < 0)
return gnutls_assert_val(ret);
ret = _gnutls_buffer_init_handshake_mbuffer(&buf);
if (ret < 0) {
gnutls_assert();
goto cleanup;
}
ret = _gnutls_buffer_append_data(&buf, se->aid.id, 2);
if (ret < 0) {
gnutls_assert();
goto cleanup;
}
ret = _gnutls_buffer_append_data_prefix(&buf, 16, sig.data, sig.size);
if (ret < 0) {
gnutls_assert();
goto cleanup;
}
bufel = _gnutls_buffer_to_mbuffer(&buf);
gnutls_free(sig.data);
}
return _gnutls_send_handshake(session, bufel, GNUTLS_HANDSHAKE_CERTIFICATE_VERIFY);
cleanup:
gnutls_free(sig.data);
_gnutls_buffer_clear(&buf);
return ret;
}
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