crypto.c

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/*
 *   This program is is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation; either version 2 of the License, or (at
 *   your option) any later version.
 *
 *   This program 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 General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program; if not, write to the Free Software
 *   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
 */
 
/**
 * $Id: 7b7aa96359b1ecf54a963e6b1326ce9ad5aef1a4 $
 * @file lib/eap/crypto.c
 * @brief MPPE key calculation API
 *
 * @author Henrik Eriksson (henriken@axis.com)
 * @author Lars Viklund (larsv@axis.com)
 *
 * @copyright 2002 Axis Communications AB
 * @copyright 2006 The FreeRADIUS server project
 */
 
RCSID("$Id: 7b7aa96359b1ecf54a963e6b1326ce9ad5aef1a4 $")
USES_APPLE_DEPRECATED_API       /* OpenSSL API has been deprecated by Apple */
 
#define __STDC_WANT_LIB_EXT1__ 1
#include <string.h>
 
#include <freeradius-devel/util/sha1.h>
#include <freeradius-devel/tls/base.h>
#include <freeradius-devel/tls/log.h>
 
#include "tls.h"
#include "base.h"
#include "attrs.h"
 
#include <openssl/hmac.h>
 
/** Initialize the PRF label fields
 *
 */
void eap_crypto_prf_label_init(eap_tls_prf_label_t *prf_label, eap_session_t *eap_session,
                              char const *keying_prf_label, size_t keying_prf_label_len)
{
#ifdef TLS1_3_VERSION
        eap_tls_session_t       *eap_tls_session = talloc_get_type_abort(eap_session->opaque, eap_tls_session_t);
 
        if (eap_tls_session->tls_session->info.version == TLS1_3_VERSION) {
                prf_label->keying_prf_label = "EXPORTER_EAP_TLS_Key_Material";
                prf_label->keying_prf_label_len = sizeof("EXPORTER_EAP_TLS_Key_Material") - 1;
 
                prf_label->sessid_prf_label = "EXPORTER_EAP_TLS_Method-Id";
                prf_label->sessid_prf_label_len = sizeof("EXPORTER_EAP_TLS_Method-Id") - 1;
 
                prf_label->context[0] = eap_session->type;
                prf_label->context_len = 1;
                prf_label->use_context = 1;
                return;
        }
#endif
 
        prf_label->keying_prf_label = keying_prf_label;
        prf_label->keying_prf_label_len = keying_prf_label_len;
 
        prf_label->sessid_prf_label = NULL;
        prf_label->sessid_prf_label_len = 0;
 
        prf_label->context[0] = 0;
        prf_label->context_len = 0;
        prf_label->use_context = 0;
}
 
 
#define EAP_TLS_MPPE_KEY_LEN     32
 
/** Generate keys according to RFC 5216 and add to the reply
 *
 */
int eap_crypto_mppe_keys(request_t *request, SSL *ssl, eap_tls_prf_label_t *prf_label)
{
        uint8_t         out[4 * EAP_TLS_MPPE_KEY_LEN];
        uint8_t         *p;
 
        if (!prf_label->keying_prf_label) return 0;
 
        if (SSL_export_keying_material(ssl, out, sizeof(out),
                                       prf_label->keying_prf_label,
                                       prf_label->keying_prf_label_len,
                                       prf_label->context,
                                       prf_label->context_len,
                                       prf_label->use_context) != 1) {
                fr_tls_log(request, "Failed generating MPPE keys");
                return -1;
        }
 
        if (RDEBUG_ENABLED3) {
                uint8_t random[SSL3_RANDOM_SIZE];
                size_t random_len;
                uint8_t master_key[SSL_MAX_MASTER_KEY_LENGTH];
                size_t master_key_len;
 
                RDEBUG3("Key Derivation Function input");
                RINDENT();
                RDEBUG3("prf label          : %s", prf_label->keying_prf_label);
                master_key_len = SSL_SESSION_get_master_key(SSL_get_session(ssl), master_key, sizeof(master_key));
                RDEBUG3("master session key : %pH", fr_box_octets(master_key, master_key_len));
                random_len = SSL_get_client_random(ssl, random, SSL3_RANDOM_SIZE);
                RDEBUG3("client random      : %pH", fr_box_octets(random, random_len));
                random_len = SSL_get_server_random(ssl, random, SSL3_RANDOM_SIZE);
                RDEBUG3("server random      : %pH", fr_box_octets(random, random_len));
                REXDENT();
        }
 
        RDEBUG2("Adding session keys");
        p = out;
        eap_add_reply(request, attr_ms_mppe_recv_key, p, EAP_TLS_MPPE_KEY_LEN);
        p += EAP_TLS_MPPE_KEY_LEN;
        eap_add_reply(request, attr_ms_mppe_send_key, p, EAP_TLS_MPPE_KEY_LEN);
 
        eap_add_reply(request, attr_eap_msk, out, 64);
        eap_add_reply(request, attr_eap_emsk, out + 64, 64);
 
        return 0;
}
 
int eap_crypto_tls_session_id(TALLOC_CTX *ctx,
                              request_t *request, SSL *ssl, eap_tls_prf_label_t *prf_label,
                              uint8_t **out, uint8_t eap_type)
{
        uint8_t         *buff = NULL, *p;
 
        *out = NULL;
 
        if (!prf_label->sessid_prf_label) goto random_based_session_id;
 
        switch (SSL_SESSION_get_protocol_version(SSL_get_session(ssl))) {
        case SSL2_VERSION:      /* Should never happen */
        case SSL3_VERSION:      /* Should never happen */
                return - 1;
 
        case TLS1_VERSION:      /* No Method ID */
        case TLS1_1_VERSION:    /* No Method ID */
        case TLS1_2_VERSION:    /* No Method ID */
        random_based_session_id:
                MEM(buff = p = talloc_array(ctx, uint8_t, sizeof(eap_type) + (2 * SSL3_RANDOM_SIZE)));
                *p++ = eap_type;
 
                SSL_get_client_random(ssl, p, SSL3_RANDOM_SIZE);
                p += SSL3_RANDOM_SIZE;
                SSL_get_server_random(ssl, p, SSL3_RANDOM_SIZE);
                break;
 
        /*
         *      Method-Id = TLS-Exporter("EXPORTER_EAP_TLS_Method-Id", "", 64)
         *      Session-Id = <EAP-Type> || Method-Id
         */
        case TLS1_3_VERSION:
        default:
        {
                MEM(buff = p = talloc_array(ctx, uint8_t, sizeof(eap_type) + 64));
                *p++ = eap_type;
                if (SSL_export_keying_material(ssl, p, 64,
                                               prf_label->sessid_prf_label,
                                               prf_label->sessid_prf_label_len,
                                               prf_label->context,
                                               prf_label->context_len,
                                               prf_label->use_context) != 1) {
                        fr_tls_log(request, "Failed generating TLS session ID");
                        return -1;
                }
        }
                break;
        }
        *out = buff;
 
        return 0;
}