rlm_eap_tls.c

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/*
 * rlm_eap_tls.c  contains the interfaces that are called from eap
 *
 * Version:     $Id: 2259cc5d2b999c00646e5a1a0d8820ca038380f6 $
 *
 *   This program 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
 *
 * @copyright 2001 hereUare Communications, Inc. (raghud@hereuare.com)
 * @copyright 2003 Alan DeKok (aland@freeradius.org)
 * @copyright 2006 The FreeRADIUS server project
 *
 */
RCSID("$Id: 2259cc5d2b999c00646e5a1a0d8820ca038380f6 $")
USES_APPLE_DEPRECATED_API       /* OpenSSL API has been deprecated by Apple */
 
#include <freeradius-devel/tls/openssl_user_macros.h>
#ifdef HAVE_OPENSSL_RAND_H
#  include <openssl/rand.h>
#endif
#ifdef HAVE_OPENSSL_EVP_H
#  include <openssl/evp.h>
#endif
#ifdef HAVE_SYS_STAT_H
#  include <sys/stat.h>
#endif
 
#include "rlm_eap_tls.h"
 
typedef struct {
        SSL_CTX         *ssl_ctx;               //!< Thread local SSL_CTX.
} rlm_eap_tls_thread_t;
 
static conf_parser_t submodule_config[] = {
        { FR_CONF_OFFSET("tls", rlm_eap_tls_t, tls_conf_name) },
 
        { FR_CONF_OFFSET("require_client_cert", rlm_eap_tls_t, req_client_cert), .dflt = "yes" },
        { FR_CONF_OFFSET("include_length", rlm_eap_tls_t, include_length), .dflt = "yes" },
        { FR_CONF_OFFSET("virtual_server", rlm_eap_tls_t, virtual_server) },
        CONF_PARSER_TERMINATOR
};
 
static fr_dict_t const *dict_freeradius;
 
extern fr_dict_autoload_t rlm_eap_tls_dict[];
fr_dict_autoload_t rlm_eap_tls_dict[] = {
        { .out = &dict_freeradius, .proto = "freeradius" },
        { NULL }
};
 
static fr_dict_attr_t const *attr_eap_tls_require_client_cert;
 
extern fr_dict_attr_autoload_t rlm_eap_tls_dict_attr[];
fr_dict_attr_autoload_t rlm_eap_tls_dict_attr[] = {
        { .out = &attr_eap_tls_require_client_cert, .name = "EAP-TLS-Require-Client-Cert", .type = FR_TYPE_UINT32, .dict = &dict_freeradius },
        { NULL }
};
 
static unlang_action_t mod_handshake_done(rlm_rcode_t *p_result, UNUSED module_ctx_t const *mctx,
                                          UNUSED request_t *request)
{
        RETURN_MODULE_OK;
}
 
static unlang_action_t mod_handshake_resume(rlm_rcode_t *p_result, module_ctx_t const *mctx, request_t *request)
{
        eap_session_t           *eap_session = talloc_get_type_abort(mctx->rctx, eap_session_t);
        eap_tls_session_t       *eap_tls_session = talloc_get_type_abort(eap_session->opaque, eap_tls_session_t);
        fr_tls_session_t        *tls_session = eap_tls_session->tls_session;
 
        if ((eap_tls_session->state == EAP_TLS_INVALID) || (eap_tls_session->state == EAP_TLS_FAIL)) {
                REDEBUG("[eap-tls process] = %s", fr_table_str_by_value(eap_tls_status_table, eap_tls_session->state, "<INVALID>"));
        } else {
                RDEBUG2("[eap-tls process] = %s", fr_table_str_by_value(eap_tls_status_table, eap_tls_session->state, "<INVALID>"));
        }
 
        switch (eap_tls_session->state) {
        /*
         *      EAP-TLS handshake was successful, return an
         *      EAP-TLS-Success packet here.
         *
         *      If a virtual server was configured, check that
         *      it accepts the certificates, too.
         */
        case EAP_TLS_ESTABLISHED:
        {
                eap_tls_prf_label_t prf_label;
 
                eap_crypto_prf_label_init(&prf_label, eap_session,
                                          "client EAP encryption",
                                          sizeof("client EAP encryption") - 1);
 
                if (eap_tls_success(request, eap_session, &prf_label) < 0) RETURN_MODULE_FAIL;
 
                /*
                 *      Result is always OK, even if we fail to persist the
                 *      session data.
                 */
                unlang_module_yield(request, mod_handshake_done, NULL, 0, mctx->rctx);
                /*
                 *      Write the session to the session cache
                 *
                 *      We do this here (instead of relying on OpenSSL to call the
                 *      session caching callback), because we only want to write
                 *      session data to the cache if all phases were successful.
                 *
                 *      If we wrote out the cache data earlier, and the server
                 *      exited whilst the session was in progress, the supplicant
                 *      could resume the session (and get access) even if phase2
                 *      never completed.
                 */
                return fr_tls_cache_pending_push(request, tls_session);
        }
 
        /*
         *      The TLS code is still working on the TLS
         *      exchange, and it's a valid TLS request.
         *      do nothing.
         */
        case EAP_TLS_HANDLED:
                RETURN_MODULE_HANDLED;
 
        /*
         *      Handshake is done, proceed with decoding tunneled
         *      data.
         */
        case EAP_TLS_RECORD_RECV_COMPLETE:
                REDEBUG("Received unexpected tunneled data after successful handshake");
                eap_tls_fail(request, eap_session);
 
                RETURN_MODULE_INVALID;
 
        /*
         *      Anything else: fail.
         *
         *      Also, remove the session from the cache so that
         *      the client can't reuse it.
         */
        default:
                fr_tls_cache_deny(request, tls_session);
                *p_result = RLM_MODULE_REJECT;
 
                /*
                 *      We'll jump back to the caller
                 *      in the unlang stack if this
                 *      fails.
                 */
                return fr_tls_cache_pending_push(request, tls_session); /* Run any pending cache clear operations */
        }
}
 
/*
 *      Do authentication, by letting EAP-TLS do most of the work.
 */
static unlang_action_t mod_handshake_process(UNUSED rlm_rcode_t *p_result, UNUSED module_ctx_t const *mctx,
                                             request_t *request)
{
        eap_session_t           *eap_session = eap_session_get(request->parent);
 
        /*
         *      Setup the resumption frame to process the result
         */
        (void)unlang_module_yield(request, mod_handshake_resume, NULL, 0, eap_session);
 
        /*
         *      Process TLS layer until done.
         */
        return eap_tls_process(request, eap_session);
}
 
/*
 *      Send an initial eap-tls request to the peer, using the libeap functions.
 */
static unlang_action_t mod_session_init(rlm_rcode_t *p_result, module_ctx_t const *mctx, request_t *request)
{
        rlm_eap_tls_t           *inst = talloc_get_type_abort(mctx->mi->data, rlm_eap_tls_t);
        rlm_eap_tls_thread_t    *t = talloc_get_type_abort(mctx->thread, rlm_eap_tls_thread_t);
        eap_session_t           *eap_session = eap_session_get(request->parent);
        eap_tls_session_t       *eap_tls_session;
 
        fr_pair_t               *vp;
        bool                    client_cert;
 
        eap_session->tls = true;
 
        /*
         *      EAP-TLS-Require-Client-Cert attribute will override
         *      the require_client_cert configuration option.
         */
        vp = fr_pair_find_by_da(&request->control_pairs, NULL, attr_eap_tls_require_client_cert);
        if (vp) {
                client_cert = vp->vp_uint32 ? true : false;
        } else {
                client_cert = inst->req_client_cert;
        }
 
        /*
         *      EAP-TLS always requires a client certificate.
         */
        eap_session->opaque = eap_tls_session = eap_tls_session_init(request, eap_session, t->ssl_ctx, client_cert);
        if (!eap_tls_session) RETURN_MODULE_FAIL;
 
        eap_tls_session->include_length = inst->include_length;
 
        /*
         *      TLS session initialization is over.  Now handle TLS
         *      related handshaking or application data.
         */
        if (eap_tls_start(request, eap_session) < 0) {
                talloc_free(eap_tls_session);
                RETURN_MODULE_FAIL;
        }
 
        eap_session->process = mod_handshake_process;
 
        RETURN_MODULE_HANDLED;
}
 
static int mod_thread_instantiate(module_thread_inst_ctx_t const *mctx)
{
        rlm_eap_tls_t           *inst = talloc_get_type_abort(mctx->mi->data, rlm_eap_tls_t);
        rlm_eap_tls_thread_t    *t = talloc_get_type_abort(mctx->thread, rlm_eap_tls_thread_t);
 
        t->ssl_ctx = fr_tls_ctx_alloc(inst->tls_conf, false);
        if (!t->ssl_ctx) return -1;
 
        return 0;
}
 
static int mod_thread_detach(module_thread_inst_ctx_t const *mctx)
{
        rlm_eap_tls_thread_t    *t = talloc_get_type_abort(mctx->thread, rlm_eap_tls_thread_t);
 
        if (likely(t->ssl_ctx != NULL)) SSL_CTX_free(t->ssl_ctx);
        t->ssl_ctx = NULL;
 
        return 0;
}
 
/*
 *      Attach the EAP-TLS module.
 */
static int mod_instantiate(module_inst_ctx_t const *mctx)
{
        rlm_eap_tls_t   *inst = talloc_get_type_abort(mctx->mi->data, rlm_eap_tls_t);
        CONF_SECTION    *conf = mctx->mi->conf;
 
        inst->tls_conf = eap_tls_conf_parse(conf, "tls");
        if (!inst->tls_conf) {
                cf_log_err(conf, "Failed initializing SSL context");
                return -1;
        }
 
        if (inst->virtual_server && !virtual_server_find(inst->virtual_server)) {
                cf_log_err_by_child(conf, "virtual_server", "Unknown virtual server '%s'", inst->virtual_server);
                return -1;
        }
 
        return 0;
}
 
/*
 *      The module name should be the only globally exported symbol.
 *      That is, everything else should be 'static'.
 */
extern rlm_eap_submodule_t rlm_eap_tls;
rlm_eap_submodule_t rlm_eap_tls = {
        .common = {
                .magic                  = MODULE_MAGIC_INIT,
                .name                   = "eap_tls",
                .inst_size              = sizeof(rlm_eap_tls_t),
                .config                 = submodule_config,
                .instantiate            = mod_instantiate,      /* Create new submodule instance */
 
                .thread_inst_size       = sizeof(rlm_eap_tls_thread_t),
                .thread_instantiate     = mod_thread_instantiate,
                .thread_detach          = mod_thread_detach,
        },
        .provides               = { FR_EAP_METHOD_TLS },
        .session_init           = mod_session_init,     /* Initialise a new EAP session */
};