rlm_eap_peap.c

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/*
 * rlm_eap_peap.c  contains the interfaces that are called from eap
 *
 * Version:     $Id: d982f07c1c806e71157d8cfd48d54d8b316fbd93 $
 *
 *   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 2003 Alan DeKok (aland@freeradius.org)
 * @copyright 2006 The FreeRADIUS server project
 */
RCSID("$Id: d982f07c1c806e71157d8cfd48d54d8b316fbd93 $")
 
#include <freeradius-devel/eap/tls.h>
#include "eap_peap.h"
 
typedef struct {
        SSL_CTX         *ssl_ctx;                       //!< Thread local SSL_CTX.
} rlm_eap_peap_thread_t;
 
typedef struct {
        char const              *tls_conf_name;         //!< TLS configuration.
        fr_tls_conf_t           *tls_conf;
 
        bool                    use_tunneled_reply;     //!< Use the reply attributes from the tunneled session in
                                                        //!< the non-tunneled reply to the client.
 
        bool                    copy_request_to_tunnel; //!< Use SOME of the request attributes from outside of the
                                                        //!< tunneled session in the tunneled request.
#ifdef WITH_PROXY
        bool                    proxy_tunneled_request_as_eap;  //!< Proxy tunneled session as EAP, or as de-capsulated
                                                        //!< protocol.
#endif
        char const              *virtual_server;        //!< Virtual server for inner tunnel session.
 
        bool                    req_client_cert;        //!< Do we do require a client cert?
} rlm_eap_peap_t;
 
static conf_parser_t submodule_config[] = {
        { FR_CONF_OFFSET("tls", rlm_eap_peap_t, tls_conf_name) },
 
        { FR_CONF_DEPRECATED("copy_request_to_tunnel", rlm_eap_peap_t, NULL), .dflt = "no" },
 
        { FR_CONF_DEPRECATED("use_tunneled_reply", rlm_eap_peap_t, NULL), .dflt = "no" },
 
#ifdef WITH_PROXY
        { FR_CONF_OFFSET("proxy_tunneled_request_as_eap", rlm_eap_peap_t, proxy_tunneled_request_as_eap), .dflt = "yes" },
#endif
 
        { FR_CONF_OFFSET_FLAGS("virtual_server", CONF_FLAG_REQUIRED | CONF_FLAG_NOT_EMPTY, rlm_eap_peap_t, virtual_server) },
 
        { FR_CONF_OFFSET("require_client_cert", rlm_eap_peap_t, req_client_cert), .dflt = "no" },
 
        CONF_PARSER_TERMINATOR
};
 
static fr_dict_t const *dict_freeradius;
static fr_dict_t const *dict_radius;
 
extern fr_dict_autoload_t rlm_eap_peap_dict[];
fr_dict_autoload_t rlm_eap_peap_dict[] = {
        { .out = &dict_freeradius, .proto = "freeradius" },
        { .out = &dict_radius, .proto = "radius" },
        { NULL }
};
 
fr_dict_attr_t const *attr_auth_type;
fr_dict_attr_t const *attr_eap_tls_require_client_cert;
fr_dict_attr_t const *attr_proxy_to_realm;
 
fr_dict_attr_t const *attr_eap_message;
fr_dict_attr_t const *attr_freeradius_proxied_to;
fr_dict_attr_t const *attr_user_name;
 
extern fr_dict_attr_autoload_t rlm_eap_peap_dict_attr[];
fr_dict_attr_autoload_t rlm_eap_peap_dict_attr[] = {
        { .out = &attr_auth_type, .name = "Auth-Type", .type = FR_TYPE_UINT32, .dict = &dict_freeradius },
        { .out = &attr_eap_tls_require_client_cert, .name = "EAP-TLS-Require-Client-Cert", .type = FR_TYPE_UINT32, .dict = &dict_freeradius },
        { .out = &attr_proxy_to_realm, .name = "Proxy-To-Realm", .type = FR_TYPE_STRING, .dict = &dict_freeradius },
 
        { .out = &attr_eap_message, .name = "EAP-Message", .type = FR_TYPE_OCTETS, .dict = &dict_radius },
        { .out = &attr_freeradius_proxied_to, .name = "Vendor-Specific.FreeRADIUS.Proxied-To", .type = FR_TYPE_IPV4_ADDR, .dict = &dict_radius },
        { .out = &attr_user_name, .name = "User-Name", .type = FR_TYPE_STRING, .dict = &dict_radius },
        { NULL }
};
 
 
/*
 *      Allocate the PEAP per-session data
 */
static peap_tunnel_t *peap_alloc(TALLOC_CTX *ctx, rlm_eap_peap_t *inst)
{
        peap_tunnel_t *t;
 
        t = talloc_zero(ctx, peap_tunnel_t);
 
#ifdef WITH_PROXY
        t->proxy_tunneled_request_as_eap = inst->proxy_tunneled_request_as_eap;
#endif
        t->virtual_server = inst->virtual_server;
        t->session_resumption_state = PEAP_RESUMPTION_MAYBE;
 
        return t;
}
 
static unlang_action_t mod_handshake_resume(rlm_rcode_t *p_result, module_ctx_t const *mctx, request_t *request)
{
        rlm_eap_peap_t          *inst = talloc_get_type(mctx->inst->data, rlm_eap_peap_t);
 
        rlm_rcode_t             rcode;
 
        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;
        peap_tunnel_t           *peap = talloc_get_type_abort(tls_session->opaque, peap_tunnel_t);
 
        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, tell the
         *      client to keep talking.
         *
         *      If this was EAP-TLS, we would just return
         *      an EAP-TLS-Success packet here.
         */
        case EAP_TLS_ESTABLISHED:
                peap->status = PEAP_STATUS_TUNNEL_ESTABLISHED;
                break;
 
        /*
         *      The TLS code is still working on the TLS
         *      exchange, and it's a valid TLS request.
         *      do nothing.
         */
        case EAP_TLS_HANDLED:
                /*
                 *      FIXME: If the SSL session is established, grab the state
                 *      and EAP id from the inner tunnel, and update it with
                 *      the expected EAP id!
                 */
                RETURN_MODULE_HANDLED;
 
        /*
         *      Handshake is done, proceed with decoding tunneled
         *      data.
         */
        case EAP_TLS_RECORD_RECV_COMPLETE:
                /*
                 *     TLSv1.3 makes application data immediately
                 *     available when the handshake is finished.
                 */
                if (SSL_is_init_finished(tls_session->ssl) && (peap->status == PEAP_STATUS_INVALID)) {
                        peap->status = PEAP_STATUS_TUNNEL_ESTABLISHED;
                }
                break;
 
        /*
         *      Anything else: fail.
         */
        default:
                RETURN_MODULE_FAIL;
        }
 
        /*
         *      Session is established, proceed with decoding
         *      tunneled data.
         */
        RDEBUG2("Session established.  Decoding tunneled data");
 
        /*
         *      We may need PEAP data associated with the session, so
         *      allocate it here, if it wasn't already alloacted.
         */
        if (!tls_session->opaque) tls_session->opaque = peap_alloc(tls_session, inst);
 
        /*
         *      Process the PEAP portion of the request.
         */
        eap_peap_process(&rcode, request, eap_session, tls_session);
        switch (rcode) {
        case RLM_MODULE_REJECT:
                eap_tls_fail(request, eap_session);
                break;
 
        case RLM_MODULE_HANDLED:
                eap_tls_request(request, eap_session);
                break;
 
        case RLM_MODULE_OK:
        {
                eap_tls_prf_label_t prf_label;
 
                eap_crypto_prf_label_init(&prf_label, eap_session,
                                          "client EAP encryption",
                                          sizeof("client EAP encryption") - 1);
 
                /*
                 *      Success: Automatically return MPPE keys.
                 */
                if (eap_tls_success(request, eap_session, &prf_label) > 0) RETURN_MODULE_FAIL;
                *p_result = rcode;
 
                /*
                 *      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);
        }
 
        /*
         *      No response packet, MUST be proxying it.
         *      The main EAP module will take care of discovering
         *      that the request now has a "proxy" packet, and
         *      will proxy it, rather than returning an EAP packet.
         */
        case RLM_MODULE_UPDATED:
                break;
 
        default:
                eap_tls_fail(request, eap_session);
                break;
        }
 
        RETURN_MODULE_RCODE(rcode);
}
 
/*
 *      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_peap_t          *inst = talloc_get_type_abort(mctx->inst->data, rlm_eap_peap_t);
        rlm_eap_peap_thread_t   *t = talloc_get_type_abort(mctx->thread, rlm_eap_peap_thread_t);
        eap_session_t           *eap_session = eap_session_get(request->parent);
        eap_tls_session_t       *eap_tls_session;
        fr_tls_session_t        *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_session->opaque = eap_tls_session = eap_tls_session_init(request, eap_session, t->ssl_ctx, client_cert);
        if (!eap_tls_session) RETURN_MODULE_FAIL;
 
        tls_session = eap_tls_session->tls_session;
 
        /*
         *      As it is a poorly designed protocol, PEAP uses
         *      bits in the TLS header to indicate PEAP
         *      version numbers.  For now, we only support
         *      PEAP version 0, so it doesn't matter too much.
         *      However, if we support later versions of PEAP,
         *      we will need this flag to indicate which
         *      version we're currently dealing with.
         */
        eap_tls_session->base_flags = 0x00;
 
        /*
         *      PEAP version 0 requires 'include_length = no',
         *      so rather than hoping the user figures it out,
         *      we force it here.
         */
        eap_tls_session->include_length = false;
 
        /*
         *      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;
        }
 
        /*
         *      Session resumption requires the storage of data, so
         *      allocate it if it doesn't already exist.
         */
        tls_session->opaque = peap_alloc(tls_session, inst);
 
        eap_session->process = mod_handshake_process;
 
        RETURN_MODULE_HANDLED;
}
 
static int mod_thread_instantiate(module_thread_inst_ctx_t const *mctx)
{
        rlm_eap_peap_t          *inst = talloc_get_type_abort(mctx->inst->data, rlm_eap_peap_t);
        rlm_eap_peap_thread_t   *t = talloc_get_type_abort(mctx->thread, rlm_eap_peap_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_peap_thread_t   *t = talloc_get_type_abort(mctx->thread, rlm_eap_peap_thread_t);
 
        if (likely(t->ssl_ctx != NULL)) SSL_CTX_free(t->ssl_ctx);
        t->ssl_ctx = NULL;
 
        return 0;
}
 
/*
 *      Attach the module.
 */
static int mod_instantiate(module_inst_ctx_t const *mctx)
{
        rlm_eap_peap_t          *inst = talloc_get_type_abort(mctx->inst->data, rlm_eap_peap_t);
        CONF_SECTION            *conf = mctx->inst->conf;
 
        if (!virtual_server_find(inst->virtual_server)) {
                cf_log_err_by_child(conf, "virtual_server", "Unknown virtual server '%s'", inst->virtual_server);
                return -1;
        }
 
        /*
         *      Read tls configuration, either from group given by 'tls'
         *      option, or from the eap-tls configuration.
         */
        inst->tls_conf = eap_tls_conf_parse(conf, "tls");
        if (!inst->tls_conf) {
                cf_log_err(conf, "Failed initializing SSL context");
                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_peap;
rlm_eap_submodule_t rlm_eap_peap = {
        .common = {
                .magic                  = MODULE_MAGIC_INIT,
                .name                   = "eap_peap",
                .inst_size              = sizeof(rlm_eap_peap_t),
                .config                 = submodule_config,
                .instantiate            = mod_instantiate,
 
                .thread_inst_size       = sizeof(rlm_eap_peap_thread_t),
                .thread_instantiate     = mod_thread_instantiate,
                .thread_detach          = mod_thread_detach,
        },
        .provides               = { FR_EAP_METHOD_PEAP },
        .session_init           = mod_session_init,     /* Initialise a new EAP session */
};