2 * rlm_eap_tls.c contains the interfaces that are called from eap
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
20 * Copyright 2001 hereUare Communications, Inc. <raghud@hereuare.com>
21 * Copyright 2003 Alan DeKok <aland@freeradius.org>
24 #include <freeradius-devel/autoconf.h>
27 #ifdef HAVE_OPENSSL_RAND_H
28 #include <openssl/rand.h>
31 static CONF_PARSER module_config[] = {
32 { "rsa_key_exchange", PW_TYPE_BOOLEAN,
33 offsetof(EAP_TLS_CONF, rsa_key), NULL, "no" },
34 { "dh_key_exchange", PW_TYPE_BOOLEAN,
35 offsetof(EAP_TLS_CONF, dh_key), NULL, "yes" },
36 { "rsa_key_length", PW_TYPE_INTEGER,
37 offsetof(EAP_TLS_CONF, rsa_key_length), NULL, "512" },
38 { "dh_key_length", PW_TYPE_INTEGER,
39 offsetof(EAP_TLS_CONF, dh_key_length), NULL, "512" },
40 { "verify_depth", PW_TYPE_INTEGER,
41 offsetof(EAP_TLS_CONF, verify_depth), NULL, "0" },
42 { "CA_path", PW_TYPE_FILENAME,
43 offsetof(EAP_TLS_CONF, ca_path), NULL, NULL },
44 { "pem_file_type", PW_TYPE_BOOLEAN,
45 offsetof(EAP_TLS_CONF, file_type), NULL, "yes" },
46 { "private_key_file", PW_TYPE_FILENAME,
47 offsetof(EAP_TLS_CONF, private_key_file), NULL, NULL },
48 { "certificate_file", PW_TYPE_FILENAME,
49 offsetof(EAP_TLS_CONF, certificate_file), NULL, NULL },
50 { "CA_file", PW_TYPE_FILENAME,
51 offsetof(EAP_TLS_CONF, ca_file), NULL, NULL },
52 { "private_key_password", PW_TYPE_STRING_PTR,
53 offsetof(EAP_TLS_CONF, private_key_password), NULL, NULL },
54 { "dh_file", PW_TYPE_STRING_PTR,
55 offsetof(EAP_TLS_CONF, dh_file), NULL, NULL },
56 { "random_file", PW_TYPE_STRING_PTR,
57 offsetof(EAP_TLS_CONF, random_file), NULL, NULL },
58 { "fragment_size", PW_TYPE_INTEGER,
59 offsetof(EAP_TLS_CONF, fragment_size), NULL, "1024" },
60 { "include_length", PW_TYPE_BOOLEAN,
61 offsetof(EAP_TLS_CONF, include_length), NULL, "yes" },
62 { "check_crl", PW_TYPE_BOOLEAN,
63 offsetof(EAP_TLS_CONF, check_crl), NULL, "no"},
64 { "check_cert_cn", PW_TYPE_STRING_PTR,
65 offsetof(EAP_TLS_CONF, check_cert_cn), NULL, NULL},
66 { "cipher_list", PW_TYPE_STRING_PTR,
67 offsetof(EAP_TLS_CONF, cipher_list), NULL, NULL},
69 { NULL, -1, 0, NULL, NULL } /* end the list */
74 * TODO: Check for the type of key exchange * like conf->dh_key
76 static int load_dh_params(SSL_CTX *ctx, char *file)
81 if ((bio = BIO_new_file(file, "r")) == NULL) {
82 radlog(L_ERR, "rlm_eap_tls: Unable to open DH file - %s", file);
86 dh = PEM_read_bio_DHparams(bio, NULL, NULL, NULL);
88 if (SSL_CTX_set_tmp_dh(ctx, dh) < 0) {
89 radlog(L_ERR, "rlm_eap_tls: Unable to set DH parameters");
99 * Generte ephemeral RSA keys.
101 static int generate_eph_rsa_key(SSL_CTX *ctx)
105 rsa = RSA_generate_key(512, RSA_F4, NULL, NULL);
107 if (!SSL_CTX_set_tmp_rsa(ctx, rsa)) {
108 radlog(L_ERR, "rlm_eap_tls: Couldn't set RSA key");
118 * Before trusting a certificate, you must make sure that the
119 * certificate is 'valid'. There are several steps that your
120 * application can take in determining if a certificate is
121 * valid. Commonly used steps are:
123 * 1.Verifying the certificate's signature, and verifying that
124 * the certificate has been issued by a trusted Certificate
127 * 2.Verifying that the certificate is valid for the present date
128 * (i.e. it is being presented within its validity dates).
130 * 3.Verifying that the certificate has not been revoked by its
131 * issuing Certificate Authority, by checking with respect to a
132 * Certificate Revocation List (CRL).
134 * 4.Verifying that the credentials presented by the certificate
135 * fulfill additional requirements specific to the application,
136 * such as with respect to access control lists or with respect
137 * to OCSP (Online Certificate Status Processing).
139 * NOTE: This callback will be called multiple times based on the
140 * depth of the root certificate chain
142 static int cbtls_verify(int ok, X509_STORE_CTX *ctx)
144 char subject[256]; /* Used for the subject name */
145 char issuer[256]; /* Used for the issuer name */
148 EAP_HANDLER *handler = NULL;
155 client_cert = X509_STORE_CTX_get_current_cert(ctx);
156 err = X509_STORE_CTX_get_error(ctx);
157 depth = X509_STORE_CTX_get_error_depth(ctx);
160 radlog(L_ERR,"--> verify error:num=%d:%s\n",err,
161 X509_verify_cert_error_string(err));
165 * Catch too long Certificate chains
169 * Retrieve the pointer to the SSL of the connection currently treated
170 * and the application specific data stored into the SSL object.
172 ssl = X509_STORE_CTX_get_ex_data(ctx, SSL_get_ex_data_X509_STORE_CTX_idx());
173 handler = (EAP_HANDLER *)SSL_get_ex_data(ssl, 0);
174 conf = (EAP_TLS_CONF *)SSL_get_ex_data(ssl, 1);
177 * Get the Subject & Issuer
179 subject[0] = issuer[0] = '\0';
180 X509_NAME_oneline(X509_get_subject_name(client_cert), subject, 256);
181 X509_NAME_oneline(X509_get_issuer_name(ctx->current_cert), issuer, 256);
184 * Get the Common Name
186 X509_NAME_get_text_by_NID(X509_get_subject_name(client_cert),
187 NID_commonName, buf, 256);
189 switch (ctx->error) {
191 case X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT:
192 radlog(L_ERR, "issuer= %s\n", issuer);
194 case X509_V_ERR_CERT_NOT_YET_VALID:
195 case X509_V_ERR_ERROR_IN_CERT_NOT_BEFORE_FIELD:
196 radlog(L_ERR, "notBefore=");
198 ASN1_TIME_print(bio_err, X509_get_notBefore(ctx->current_cert));
201 case X509_V_ERR_CERT_HAS_EXPIRED:
202 case X509_V_ERR_ERROR_IN_CERT_NOT_AFTER_FIELD:
203 radlog(L_ERR, "notAfter=");
205 ASN1_TIME_print(bio_err, X509_get_notAfter(ctx->current_cert));
211 * If we're at the actual client cert and the conf tells
212 * us to, check the CN in the cert against the xlat'ed
215 if (depth == 0 && conf->check_cert_cn != NULL) {
216 if (!radius_xlat(cn_str, sizeof(cn_str), conf->check_cert_cn, handler->request, NULL)) {
217 radlog(L_ERR, "rlm_eap_tls (%s): xlat failed.",
218 conf->check_cert_cn);
219 /* if this fails, fail the verification */
222 DEBUG2(" rlm_eap_tls: checking certificate CN (%s) with xlat'ed value (%s)", buf, cn_str);
223 if (strncmp(cn_str, buf, sizeof(buf)) != 0) {
225 radlog(L_AUTH, "rlm_eap_tls: Certificate CN (%s) does not match specified value (%s)!", buf, cn_str);
229 if (debug_flag > 0) {
230 radlog(L_INFO, "chain-depth=%d, ", depth);
236 radlog(L_INFO, "error=%d", err);
238 radlog(L_INFO, "--> User-Name = %s", handler->identity);
239 radlog(L_INFO, "--> BUF-Name = %s", buf);
240 radlog(L_INFO, "--> subject = %s", subject);
241 radlog(L_INFO, "--> issuer = %s", issuer);
242 radlog(L_INFO, "--> verify return:%d", my_ok);
249 * Create Global context SSL and use it in every new session
251 * - Load the trusted CAs
252 * - Load the Private key & the certificate
253 * - Set the Context options & Verify options
255 static SSL_CTX *init_tls_ctx(EAP_TLS_CONF *conf)
259 X509_STORE *certstore;
260 int verify_mode = SSL_VERIFY_NONE;
265 * Add all the default ciphers and message digests
266 * Create our context.
269 SSL_load_error_strings();
271 meth = TLSv1_method();
272 ctx = SSL_CTX_new(meth);
275 * Identify the type of certificates that needs to be loaded
277 if (conf->file_type) {
278 type = SSL_FILETYPE_PEM;
280 type = SSL_FILETYPE_ASN1;
284 * Set the password to load private key
286 if (conf->private_key_password) {
287 SSL_CTX_set_default_passwd_cb_userdata(ctx, conf->private_key_password);
288 SSL_CTX_set_default_passwd_cb(ctx, cbtls_password);
292 * Load our keys and certificates
294 * If certificates are of type PEM then we can make use
295 * of cert chain authentication using openssl api call
296 * SSL_CTX_use_certificate_chain_file. Please see how
297 * the cert chain needs to be given in PEM from
300 if (type == SSL_FILETYPE_PEM) {
301 radlog(L_INFO, "rlm_eap_tls: Loading the certificate file as a chain");
302 if (!(SSL_CTX_use_certificate_chain_file(ctx, conf->certificate_file))) {
303 radlog(L_ERR, "rlm_eap: SSL error %s", ERR_error_string(ERR_get_error(), NULL));
304 radlog(L_ERR, "rlm_eap_tls: Error reading certificate file");
308 } else if (!(SSL_CTX_use_certificate_file(ctx, conf->certificate_file, type))) {
309 radlog(L_ERR, "rlm_eap: SSL error %s", ERR_error_string(ERR_get_error(), NULL));
310 radlog(L_ERR, "rlm_eap_tls: Error reading certificate file");
314 /* Load the CAs we trust */
315 if (!SSL_CTX_load_verify_locations(ctx, conf->ca_file, conf->ca_path)) {
316 radlog(L_ERR, "rlm_eap: SSL error %s", ERR_error_string(ERR_get_error(), NULL));
317 radlog(L_ERR, "rlm_eap_tls: Error reading Trusted root CA list");
320 SSL_CTX_set_client_CA_list(ctx, SSL_load_client_CA_file(conf->ca_file));
321 if (!(SSL_CTX_use_PrivateKey_file(ctx, conf->private_key_file, type))) {
322 radlog(L_ERR, "rlm_eap: SSL error %s", ERR_error_string(ERR_get_error(), NULL));
323 radlog(L_ERR, "rlm_eap_tls: Error reading private key file");
328 * Check if the loaded private key is the right one
330 if (!SSL_CTX_check_private_key(ctx)) {
331 radlog(L_ERR, "rlm_eap_tls: Private key does not match the certificate public key");
338 ctx_options |= SSL_OP_NO_SSLv2;
339 ctx_options |= SSL_OP_NO_SSLv3;
342 * SSL_OP_SINGLE_DH_USE must be used in order to prevent
343 * small subgroup attacks and forward secrecy. Always
346 * SSL_OP_SINGLE_DH_USE has an impact on the computer
347 * time needed during negotiation, but it is not very
350 ctx_options |= SSL_OP_SINGLE_DH_USE;
351 SSL_CTX_set_options(ctx, ctx_options);
354 * TODO: Set the RSA & DH
355 * SSL_CTX_set_tmp_rsa_callback(ctx, cbtls_rsa);
356 * SSL_CTX_set_tmp_dh_callback(ctx, cbtls_dh);
360 * set the message callback to identify the type of
361 * message. For every new session, there can be a
362 * different callback argument.
364 * SSL_CTX_set_msg_callback(ctx, cbtls_msg);
367 /* Set Info callback */
368 SSL_CTX_set_info_callback(ctx, cbtls_info);
371 * Check the certificates for revocation.
373 #ifdef X509_V_FLAG_CRL_CHECK
374 if (conf->check_crl) {
375 certstore = SSL_CTX_get_cert_store(ctx);
376 if (certstore == NULL) {
377 radlog(L_ERR, "rlm_eap: SSL error %s", ERR_error_string(ERR_get_error(), NULL));
378 radlog(L_ERR, "rlm_eap_tls: Error reading Certificate Store");
381 X509_STORE_set_flags(certstore, X509_V_FLAG_CRL_CHECK);
387 * Always verify the peer certificate
389 verify_mode |= SSL_VERIFY_PEER;
390 verify_mode |= SSL_VERIFY_FAIL_IF_NO_PEER_CERT;
391 verify_mode |= SSL_VERIFY_CLIENT_ONCE;
392 SSL_CTX_set_verify(ctx, verify_mode, cbtls_verify);
394 if (conf->verify_depth) {
395 SSL_CTX_set_verify_depth(ctx, conf->verify_depth);
398 /* Load randomness */
399 if (!(RAND_load_file(conf->random_file, 1024*1024))) {
400 radlog(L_ERR, "rlm_eap: SSL error %s", ERR_error_string(ERR_get_error(), NULL));
401 radlog(L_ERR, "rlm_eap_tls: Error loading randomness");
406 * Set the cipher list if we were told to
408 if (conf->cipher_list) {
409 if (!SSL_CTX_set_cipher_list(ctx, conf->cipher_list)) {
410 radlog(L_ERR, "rlm_eap_tls: Error setting cipher list");
420 * Detach the EAP-TLS module.
422 static int eaptls_detach(void *arg)
427 inst = (eap_tls_t *) arg;
431 if (conf->dh_file) free(conf->dh_file);
432 conf->dh_file = NULL;
433 if (conf->certificate_file) free(conf->certificate_file);
434 conf->certificate_file = NULL;
435 if (conf->private_key_file) free(conf->private_key_file);
436 conf->private_key_file = NULL;
437 if (conf->private_key_password) free(conf->private_key_password);
438 conf->private_key_password = NULL;
439 if (conf->random_file) free(conf->random_file);
440 conf->random_file = NULL;
446 if (inst->ctx) SSL_CTX_free(inst->ctx);
456 * Attach the EAP-TLS module.
458 static int eaptls_attach(CONF_SECTION *cs, void **instance)
463 /* Store all these values in the data structure for later references */
464 inst = (eap_tls_t *)malloc(sizeof(*inst));
466 radlog(L_ERR, "rlm_eap_tls: out of memory");
469 memset(inst, 0, sizeof(*inst));
472 * Parse the config file & get all the configured values
474 conf = (EAP_TLS_CONF *)malloc(sizeof(*conf));
476 radlog(L_ERR, "rlm_eap_tls: out of memory");
479 memset(conf, 0, sizeof(*conf));
482 if (cf_section_parse(cs, conf, module_config) < 0) {
491 inst->ctx = init_tls_ctx(conf);
492 if (inst->ctx == NULL) {
497 if (load_dh_params(inst->ctx, conf->dh_file) < 0) {
501 if (generate_eph_rsa_key(inst->ctx) < 0) {
513 * Send an initial eap-tls request to the peer.
515 * Frame eap reply packet.
516 * len = header + type + tls_typedata
517 * tls_typedata = flags(Start (S) bit set, and no data)
519 * Once having received the peer's Identity, the EAP server MUST
520 * respond with an EAP-TLS/Start packet, which is an
521 * EAP-Request packet with EAP-Type=EAP-TLS, the Start (S) bit
522 * set, and no data. The EAP-TLS conversation will then begin,
523 * with the peer sending an EAP-Response packet with
524 * EAP-Type = EAP-TLS. The data field of that packet will
527 * Fragment length is Framed-MTU - 4.
529 * http://mail.frascone.com/pipermail/public/eap/2003-July/001426.html
531 static int eaptls_initiate(void *type_arg, EAP_HANDLER *handler)
537 int client_cert = TRUE;
540 inst = (eap_tls_t *)type_arg;
543 * If we're TTLS or PEAP, then do NOT require a client
546 * FIXME: This should be more configurable.
548 if (handler->eap_type != PW_EAP_TLS) {
549 vp = pairfind(handler->request->config_items,
550 PW_EAP_TLS_REQUIRE_CLIENT_CERT);
554 client_cert = vp->lvalue;
559 * Every new session is started only from EAP-TLS-START.
560 * Before Sending EAP-TLS-START, open a new SSL session.
561 * Create all the required data structures & store them
562 * in Opaque. So that we can use these data structures
563 * when we get the response
565 ssn = eaptls_new_session(inst->ctx, client_cert);
571 * Verify the peer certificate, if asked.
574 DEBUG2(" rlm_eap_tls: Requiring client certificate");
575 verify_mode = SSL_VERIFY_PEER;
576 verify_mode |= SSL_VERIFY_FAIL_IF_NO_PEER_CERT;
577 verify_mode |= SSL_VERIFY_CLIENT_ONCE;
579 SSL_set_verify(ssn->ssl, verify_mode, cbtls_verify);
582 * Create a structure for all the items required to be
583 * verified for each client and set that as opaque data
586 * NOTE: If we want to set each item sepearately then
587 * this index should be global.
589 SSL_set_ex_data(ssn->ssl, 0, (void *)handler);
590 SSL_set_ex_data(ssn->ssl, 1, (void *)inst->conf);
592 ssn->length_flag = inst->conf->include_length;
595 * We set a default fragment size, unless the Framed-MTU
596 * tells us it's too big.
598 ssn->offset = inst->conf->fragment_size;
599 vp = pairfind(handler->request->packet->vps, PW_FRAMED_MTU);
600 if (vp && ((vp->lvalue - 4) < ssn->offset)) {
601 ssn->offset = vp->lvalue - 4;
604 handler->opaque = ((void *)ssn);
605 handler->free_opaque = session_free;
607 DEBUG2(" rlm_eap_tls: Initiate");
610 * PEAP-specific breakage.
612 if (handler->eap_type == PW_EAP_PEAP) {
614 * As it is a poorly designed protocol, PEAP uses
615 * bits in the TLS header to indicate PEAP
616 * version numbers. For now, we only support
617 * PEAP version 0, so it doesn't matter too much.
618 * However, if we support later versions of PEAP,
619 * we will need this flag to indicate which
620 * version we're currently dealing with.
622 ssn->peap_flag = 0x00;
625 * PEAP version 0 requires 'include_length = no',
626 * so rather than hoping the user figures it out,
629 ssn->length_flag = 0;
633 * TLS session initialization is over. Now handle TLS
634 * related handshaking or application data.
636 status = eaptls_start(handler->eap_ds, ssn->peap_flag);
637 DEBUG2(" rlm_eap_tls: Start returned %d", status);
642 * The next stage to process the packet.
644 handler->stage = AUTHENTICATE;
650 * Do authentication, by letting EAP-TLS do most of the work.
652 static int eaptls_authenticate(void *arg UNUSED, EAP_HANDLER *handler)
654 eaptls_status_t status;
655 tls_session_t *tls_session = (tls_session_t *) handler->opaque;
657 DEBUG2(" rlm_eap_tls: Authenticate");
659 status = eaptls_process(handler);
660 DEBUG2(" eaptls_process returned %d\n", status);
663 * EAP-TLS handshake was successful, return an
664 * EAP-TLS-Success packet here.
670 * The TLS code is still working on the TLS
671 * exchange, and it's a valid TLS request.
678 * Handshake is done, proceed with decoding tunneled
682 DEBUG2(" rlm_eap_tls: Received unexpected tunneled data after successful handshake.");
684 if (debug_flag > 2) {
686 unsigned int data_len;
687 unsigned char buffer[1024];
689 data_len = (tls_session->record_minus)(&tls_session->dirty_in,
690 buffer, sizeof(buffer));
691 log_debug(" Tunneled data (%u bytes)\n", data_len);
692 for (i = 0; i < data_len; i++) {
693 if ((i & 0x0f) == 0x00) printf(" %x: ", i);
694 if ((i & 0x0f) == 0x0f) printf("\n");
696 printf("%02x ", buffer[i]);
702 eaptls_fail(handler->eap_ds, 0);
707 * Anything else: fail.
714 * Success: Return MPPE keys.
716 eaptls_success(handler->eap_ds, 0);
717 eaptls_gen_mppe_keys(&handler->request->reply->vps,
719 "client EAP encryption");
724 * The module name should be the only globally exported symbol.
725 * That is, everything else should be 'static'.
727 EAP_TYPE rlm_eap_tls = {
729 eaptls_attach, /* attach */
730 eaptls_initiate, /* Start the initial request */
731 NULL, /* authorization */
732 eaptls_authenticate, /* authentication */
733 eaptls_detach /* detach */