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>
26 #ifdef HAVE_OPENSSL_RAND_H
27 #include <openssl/rand.h>
30 #include "rlm_eap_tls.h"
32 static CONF_PARSER module_config[] = {
33 { "rsa_key_exchange", PW_TYPE_BOOLEAN,
34 offsetof(EAP_TLS_CONF, rsa_key), NULL, "no" },
35 { "dh_key_exchange", PW_TYPE_BOOLEAN,
36 offsetof(EAP_TLS_CONF, dh_key), NULL, "yes" },
37 { "rsa_key_length", PW_TYPE_INTEGER,
38 offsetof(EAP_TLS_CONF, rsa_key_length), NULL, "512" },
39 { "dh_key_length", PW_TYPE_INTEGER,
40 offsetof(EAP_TLS_CONF, dh_key_length), NULL, "512" },
41 { "verify_depth", PW_TYPE_INTEGER,
42 offsetof(EAP_TLS_CONF, verify_depth), NULL, "0" },
43 { "CA_path", PW_TYPE_FILENAME,
44 offsetof(EAP_TLS_CONF, ca_path), NULL, NULL },
45 { "pem_file_type", PW_TYPE_BOOLEAN,
46 offsetof(EAP_TLS_CONF, file_type), NULL, "yes" },
47 { "private_key_file", PW_TYPE_FILENAME,
48 offsetof(EAP_TLS_CONF, private_key_file), NULL, NULL },
49 { "certificate_file", PW_TYPE_FILENAME,
50 offsetof(EAP_TLS_CONF, certificate_file), NULL, NULL },
51 { "CA_file", PW_TYPE_FILENAME,
52 offsetof(EAP_TLS_CONF, ca_file), NULL, NULL },
53 { "private_key_password", PW_TYPE_STRING_PTR,
54 offsetof(EAP_TLS_CONF, private_key_password), NULL, NULL },
55 { "dh_file", PW_TYPE_STRING_PTR,
56 offsetof(EAP_TLS_CONF, dh_file), NULL, NULL },
57 { "random_file", PW_TYPE_STRING_PTR,
58 offsetof(EAP_TLS_CONF, random_file), NULL, NULL },
59 { "fragment_size", PW_TYPE_INTEGER,
60 offsetof(EAP_TLS_CONF, fragment_size), NULL, "1024" },
61 { "include_length", PW_TYPE_BOOLEAN,
62 offsetof(EAP_TLS_CONF, include_length), NULL, "yes" },
63 { "check_crl", PW_TYPE_BOOLEAN,
64 offsetof(EAP_TLS_CONF, check_crl), NULL, "no"},
65 { "check_cert_cn", PW_TYPE_STRING_PTR,
66 offsetof(EAP_TLS_CONF, check_cert_cn), NULL, NULL},
67 { "cipher_list", PW_TYPE_STRING_PTR,
68 offsetof(EAP_TLS_CONF, cipher_list), NULL, NULL},
69 { "check_cert_issuer", PW_TYPE_STRING_PTR,
70 offsetof(EAP_TLS_CONF, check_cert_issuer), NULL, NULL},
72 { NULL, -1, 0, NULL, NULL } /* end the list */
77 * TODO: Check for the type of key exchange * like conf->dh_key
79 static int load_dh_params(SSL_CTX *ctx, char *file)
84 if ((bio = BIO_new_file(file, "r")) == NULL) {
85 radlog(L_ERR, "rlm_eap_tls: Unable to open DH file - %s", file);
89 dh = PEM_read_bio_DHparams(bio, NULL, NULL, NULL);
91 if (SSL_CTX_set_tmp_dh(ctx, dh) < 0) {
92 radlog(L_ERR, "rlm_eap_tls: Unable to set DH parameters");
102 * Generte ephemeral RSA keys.
104 static int generate_eph_rsa_key(SSL_CTX *ctx)
108 rsa = RSA_generate_key(512, RSA_F4, NULL, NULL);
110 if (!SSL_CTX_set_tmp_rsa(ctx, rsa)) {
111 radlog(L_ERR, "rlm_eap_tls: Couldn't set RSA key");
121 * Before trusting a certificate, you must make sure that the
122 * certificate is 'valid'. There are several steps that your
123 * application can take in determining if a certificate is
124 * valid. Commonly used steps are:
126 * 1.Verifying the certificate's signature, and verifying that
127 * the certificate has been issued by a trusted Certificate
130 * 2.Verifying that the certificate is valid for the present date
131 * (i.e. it is being presented within its validity dates).
133 * 3.Verifying that the certificate has not been revoked by its
134 * issuing Certificate Authority, by checking with respect to a
135 * Certificate Revocation List (CRL).
137 * 4.Verifying that the credentials presented by the certificate
138 * fulfill additional requirements specific to the application,
139 * such as with respect to access control lists or with respect
140 * to OCSP (Online Certificate Status Processing).
142 * NOTE: This callback will be called multiple times based on the
143 * depth of the root certificate chain
145 static int cbtls_verify(int ok, X509_STORE_CTX *ctx)
147 char subject[1024]; /* Used for the subject name */
148 char issuer[1024]; /* Used for the issuer name */
149 char common_name[1024];
151 EAP_HANDLER *handler = NULL;
158 client_cert = X509_STORE_CTX_get_current_cert(ctx);
159 err = X509_STORE_CTX_get_error(ctx);
160 depth = X509_STORE_CTX_get_error_depth(ctx);
163 radlog(L_ERR,"--> verify error:num=%d:%s\n",err,
164 X509_verify_cert_error_string(err));
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,
182 X509_NAME_oneline(X509_get_issuer_name(ctx->current_cert), issuer,
185 subject[sizeof(subject) - 1] = '\0';
186 issuer[sizeof(issuer) - 1] = '\0';
189 * Get the Common Name
191 X509_NAME_get_text_by_NID(X509_get_subject_name(client_cert),
192 NID_commonName, common_name, sizeof(common_name));
193 common_name[sizeof(common_name) - 1] = '\0';
195 switch (ctx->error) {
197 case X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT:
198 radlog(L_ERR, "issuer= %s\n", issuer);
200 case X509_V_ERR_CERT_NOT_YET_VALID:
201 case X509_V_ERR_ERROR_IN_CERT_NOT_BEFORE_FIELD:
202 radlog(L_ERR, "notBefore=");
204 ASN1_TIME_print(bio_err, X509_get_notBefore(ctx->current_cert));
207 case X509_V_ERR_CERT_HAS_EXPIRED:
208 case X509_V_ERR_ERROR_IN_CERT_NOT_AFTER_FIELD:
209 radlog(L_ERR, "notAfter=");
211 ASN1_TIME_print(bio_err, X509_get_notAfter(ctx->current_cert));
217 * If we're at the actual client cert, apply additional
222 * If the conf tells us to, check cert issuer
223 * against the specified value and fail
224 * verification if they don't match.
226 if (conf->check_cert_issuer &&
227 (strcmp(issuer, conf->check_cert_issuer) != 0)) {
228 radlog(L_AUTH, "rlm_eap_tls: Certificate issuer (%s) does not match specified value (%s)!", issuer, conf->check_cert_issuer);
233 * If the conf tells us to, check the CN in the
234 * cert against xlat'ed value, but only if the
235 * previous checks passed.
237 if (my_ok && conf->check_cert_cn) {
238 if (!radius_xlat(cn_str, sizeof(cn_str), conf->check_cert_cn, handler->request, NULL)) {
239 radlog(L_ERR, "rlm_eap_tls (%s): xlat failed.",
240 conf->check_cert_cn);
241 /* if this fails, fail the verification */
244 DEBUG2(" rlm_eap_tls: checking certificate CN (%s) with xlat'ed value (%s)", common_name, cn_str);
245 if (strcmp(cn_str, common_name) != 0) {
246 radlog(L_AUTH, "rlm_eap_tls: Certificate CN (%s) does not match specified value (%s)!", common_name, cn_str);
250 } /* check_cert_cn */
253 if (debug_flag > 0) {
254 radlog(L_INFO, "chain-depth=%d, ", depth);
255 radlog(L_INFO, "error=%d", err);
257 radlog(L_INFO, "--> User-Name = %s", handler->identity);
258 radlog(L_INFO, "--> BUF-Name = %s", common_name);
259 radlog(L_INFO, "--> subject = %s", subject);
260 radlog(L_INFO, "--> issuer = %s", issuer);
261 radlog(L_INFO, "--> verify return:%d", my_ok);
268 * Create Global context SSL and use it in every new session
270 * - Load the trusted CAs
271 * - Load the Private key & the certificate
272 * - Set the Context options & Verify options
274 static SSL_CTX *init_tls_ctx(EAP_TLS_CONF *conf)
278 X509_STORE *certstore;
279 int verify_mode = SSL_VERIFY_NONE;
284 * Add all the default ciphers and message digests
285 * Create our context.
288 SSL_load_error_strings();
290 meth = TLSv1_method();
291 ctx = SSL_CTX_new(meth);
294 * Identify the type of certificates that needs to be loaded
296 if (conf->file_type) {
297 type = SSL_FILETYPE_PEM;
299 type = SSL_FILETYPE_ASN1;
303 * Set the password to load private key
305 if (conf->private_key_password) {
306 SSL_CTX_set_default_passwd_cb_userdata(ctx, conf->private_key_password);
307 SSL_CTX_set_default_passwd_cb(ctx, cbtls_password);
311 * Load our keys and certificates
313 * If certificates are of type PEM then we can make use
314 * of cert chain authentication using openssl api call
315 * SSL_CTX_use_certificate_chain_file. Please see how
316 * the cert chain needs to be given in PEM from
319 if (type == SSL_FILETYPE_PEM) {
320 radlog(L_INFO, "rlm_eap_tls: Loading the certificate file as a chain");
321 if (!(SSL_CTX_use_certificate_chain_file(ctx, conf->certificate_file))) {
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 certificate file");
327 } else if (!(SSL_CTX_use_certificate_file(ctx, conf->certificate_file, type))) {
328 radlog(L_ERR, "rlm_eap: SSL error %s", ERR_error_string(ERR_get_error(), NULL));
329 radlog(L_ERR, "rlm_eap_tls: Error reading certificate file");
333 /* Load the CAs we trust */
334 if (!SSL_CTX_load_verify_locations(ctx, conf->ca_file, conf->ca_path)) {
335 radlog(L_ERR, "rlm_eap: SSL error %s", ERR_error_string(ERR_get_error(), NULL));
336 radlog(L_ERR, "rlm_eap_tls: Error reading Trusted root CA list");
339 SSL_CTX_set_client_CA_list(ctx, SSL_load_client_CA_file(conf->ca_file));
340 if (!(SSL_CTX_use_PrivateKey_file(ctx, conf->private_key_file, type))) {
341 radlog(L_ERR, "rlm_eap: SSL error %s", ERR_error_string(ERR_get_error(), NULL));
342 radlog(L_ERR, "rlm_eap_tls: Error reading private key file");
347 * Check if the loaded private key is the right one
349 if (!SSL_CTX_check_private_key(ctx)) {
350 radlog(L_ERR, "rlm_eap_tls: Private key does not match the certificate public key");
357 ctx_options |= SSL_OP_NO_SSLv2;
358 ctx_options |= SSL_OP_NO_SSLv3;
361 * SSL_OP_SINGLE_DH_USE must be used in order to prevent
362 * small subgroup attacks and forward secrecy. Always
365 * SSL_OP_SINGLE_DH_USE has an impact on the computer
366 * time needed during negotiation, but it is not very
369 ctx_options |= SSL_OP_SINGLE_DH_USE;
370 SSL_CTX_set_options(ctx, ctx_options);
373 * TODO: Set the RSA & DH
374 * SSL_CTX_set_tmp_rsa_callback(ctx, cbtls_rsa);
375 * SSL_CTX_set_tmp_dh_callback(ctx, cbtls_dh);
379 * set the message callback to identify the type of
380 * message. For every new session, there can be a
381 * different callback argument.
383 * SSL_CTX_set_msg_callback(ctx, cbtls_msg);
386 /* Set Info callback */
387 SSL_CTX_set_info_callback(ctx, cbtls_info);
390 * Check the certificates for revocation.
392 #ifdef X509_V_FLAG_CRL_CHECK
393 if (conf->check_crl) {
394 certstore = SSL_CTX_get_cert_store(ctx);
395 if (certstore == NULL) {
396 radlog(L_ERR, "rlm_eap: SSL error %s", ERR_error_string(ERR_get_error(), NULL));
397 radlog(L_ERR, "rlm_eap_tls: Error reading Certificate Store");
400 X509_STORE_set_flags(certstore, X509_V_FLAG_CRL_CHECK);
406 * Always verify the peer certificate
408 verify_mode |= SSL_VERIFY_PEER;
409 verify_mode |= SSL_VERIFY_FAIL_IF_NO_PEER_CERT;
410 verify_mode |= SSL_VERIFY_CLIENT_ONCE;
411 SSL_CTX_set_verify(ctx, verify_mode, cbtls_verify);
413 if (conf->verify_depth) {
414 SSL_CTX_set_verify_depth(ctx, conf->verify_depth);
417 /* Load randomness */
418 if (!(RAND_load_file(conf->random_file, 1024*1024))) {
419 radlog(L_ERR, "rlm_eap: SSL error %s", ERR_error_string(ERR_get_error(), NULL));
420 radlog(L_ERR, "rlm_eap_tls: Error loading randomness");
425 * Set the cipher list if we were told to
427 if (conf->cipher_list) {
428 if (!SSL_CTX_set_cipher_list(ctx, conf->cipher_list)) {
429 radlog(L_ERR, "rlm_eap_tls: Error setting cipher list");
439 * Detach the EAP-TLS module.
441 static int eaptls_detach(void *arg)
446 inst = (eap_tls_t *) arg;
450 if (conf->dh_file) free(conf->dh_file);
451 conf->dh_file = NULL;
452 if (conf->certificate_file) free(conf->certificate_file);
453 conf->certificate_file = NULL;
454 if (conf->private_key_file) free(conf->private_key_file);
455 conf->private_key_file = NULL;
456 if (conf->private_key_password) free(conf->private_key_password);
457 conf->private_key_password = NULL;
458 if (conf->random_file) free(conf->random_file);
459 conf->random_file = NULL;
465 if (inst->ctx) SSL_CTX_free(inst->ctx);
475 * Attach the EAP-TLS module.
477 static int eaptls_attach(CONF_SECTION *cs, void **instance)
482 /* Store all these values in the data structure for later references */
483 inst = (eap_tls_t *)malloc(sizeof(*inst));
485 radlog(L_ERR, "rlm_eap_tls: out of memory");
488 memset(inst, 0, sizeof(*inst));
491 * Parse the config file & get all the configured values
493 conf = (EAP_TLS_CONF *)malloc(sizeof(*conf));
495 radlog(L_ERR, "rlm_eap_tls: out of memory");
498 memset(conf, 0, sizeof(*conf));
501 if (cf_section_parse(cs, conf, module_config) < 0) {
510 inst->ctx = init_tls_ctx(conf);
511 if (inst->ctx == NULL) {
516 if (load_dh_params(inst->ctx, conf->dh_file) < 0) {
520 if (generate_eph_rsa_key(inst->ctx) < 0) {
532 * Send an initial eap-tls request to the peer.
534 * Frame eap reply packet.
535 * len = header + type + tls_typedata
536 * tls_typedata = flags(Start (S) bit set, and no data)
538 * Once having received the peer's Identity, the EAP server MUST
539 * respond with an EAP-TLS/Start packet, which is an
540 * EAP-Request packet with EAP-Type=EAP-TLS, the Start (S) bit
541 * set, and no data. The EAP-TLS conversation will then begin,
542 * with the peer sending an EAP-Response packet with
543 * EAP-Type = EAP-TLS. The data field of that packet will
546 * Fragment length is Framed-MTU - 4.
548 * http://mail.frascone.com/pipermail/public/eap/2003-July/001426.html
550 static int eaptls_initiate(void *type_arg, EAP_HANDLER *handler)
556 int client_cert = TRUE;
559 inst = (eap_tls_t *)type_arg;
562 * If we're TTLS or PEAP, then do NOT require a client
565 * FIXME: This should be more configurable.
567 if (handler->eap_type != PW_EAP_TLS) {
568 vp = pairfind(handler->request->config_items,
569 PW_EAP_TLS_REQUIRE_CLIENT_CERT);
573 client_cert = vp->lvalue;
578 * Every new session is started only from EAP-TLS-START.
579 * Before Sending EAP-TLS-START, open a new SSL session.
580 * Create all the required data structures & store them
581 * in Opaque. So that we can use these data structures
582 * when we get the response
584 ssn = eaptls_new_session(inst->ctx, client_cert);
590 * Verify the peer certificate, if asked.
593 DEBUG2(" rlm_eap_tls: Requiring client certificate");
594 verify_mode = SSL_VERIFY_PEER;
595 verify_mode |= SSL_VERIFY_FAIL_IF_NO_PEER_CERT;
596 verify_mode |= SSL_VERIFY_CLIENT_ONCE;
598 SSL_set_verify(ssn->ssl, verify_mode, cbtls_verify);
601 * Create a structure for all the items required to be
602 * verified for each client and set that as opaque data
605 * NOTE: If we want to set each item sepearately then
606 * this index should be global.
608 SSL_set_ex_data(ssn->ssl, 0, (void *)handler);
609 SSL_set_ex_data(ssn->ssl, 1, (void *)inst->conf);
611 ssn->length_flag = inst->conf->include_length;
614 * We set a default fragment size, unless the Framed-MTU
615 * tells us it's too big.
617 ssn->offset = inst->conf->fragment_size;
618 vp = pairfind(handler->request->packet->vps, PW_FRAMED_MTU);
619 if (vp && ((vp->lvalue - 4) < ssn->offset)) {
620 ssn->offset = vp->lvalue - 4;
623 handler->opaque = ((void *)ssn);
624 handler->free_opaque = session_free;
626 DEBUG2(" rlm_eap_tls: Initiate");
629 * PEAP-specific breakage.
631 if (handler->eap_type == PW_EAP_PEAP) {
633 * As it is a poorly designed protocol, PEAP uses
634 * bits in the TLS header to indicate PEAP
635 * version numbers. For now, we only support
636 * PEAP version 0, so it doesn't matter too much.
637 * However, if we support later versions of PEAP,
638 * we will need this flag to indicate which
639 * version we're currently dealing with.
641 ssn->peap_flag = 0x00;
644 * PEAP version 0 requires 'include_length = no',
645 * so rather than hoping the user figures it out,
648 ssn->length_flag = 0;
652 * TLS session initialization is over. Now handle TLS
653 * related handshaking or application data.
655 status = eaptls_start(handler->eap_ds, ssn->peap_flag);
656 DEBUG2(" rlm_eap_tls: Start returned %d", status);
661 * The next stage to process the packet.
663 handler->stage = AUTHENTICATE;
669 * Do authentication, by letting EAP-TLS do most of the work.
671 static int eaptls_authenticate(void *arg UNUSED, EAP_HANDLER *handler)
673 eaptls_status_t status;
674 tls_session_t *tls_session = (tls_session_t *) handler->opaque;
676 DEBUG2(" rlm_eap_tls: Authenticate");
678 status = eaptls_process(handler);
679 DEBUG2(" eaptls_process returned %d\n", status);
682 * EAP-TLS handshake was successful, return an
683 * EAP-TLS-Success packet here.
689 * The TLS code is still working on the TLS
690 * exchange, and it's a valid TLS request.
697 * Handshake is done, proceed with decoding tunneled
701 DEBUG2(" rlm_eap_tls: Received unexpected tunneled data after successful handshake.");
703 if (debug_flag > 2) {
705 unsigned int data_len;
706 unsigned char buffer[1024];
708 data_len = (tls_session->record_minus)(&tls_session->dirty_in,
709 buffer, sizeof(buffer));
710 log_debug(" Tunneled data (%u bytes)\n", data_len);
711 for (i = 0; i < data_len; i++) {
712 if ((i & 0x0f) == 0x00) printf(" %x: ", i);
713 if ((i & 0x0f) == 0x0f) printf("\n");
715 printf("%02x ", buffer[i]);
721 eaptls_fail(handler->eap_ds, 0);
726 * Anything else: fail.
733 * Success: Return MPPE keys.
735 eaptls_success(handler->eap_ds, 0);
736 eaptls_gen_mppe_keys(&handler->request->reply->vps,
738 "client EAP encryption");
743 * The module name should be the only globally exported symbol.
744 * That is, everything else should be 'static'.
746 EAP_TYPE rlm_eap_tls = {
748 eaptls_attach, /* attach */
749 eaptls_initiate, /* Start the initial request */
750 NULL, /* authorization */
751 eaptls_authenticate, /* authentication */
752 eaptls_detach /* detach */