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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20 * Copyright 2001 hereUare Communications, Inc. <raghud@hereuare.com>
21 * Copyright 2003 Alan DeKok <aland@freeradius.org>
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_STRING_PTR,
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_STRING_PTR,
48 offsetof(EAP_TLS_CONF, private_key_file), NULL, NULL },
49 { "certificate_file", PW_TYPE_STRING_PTR,
50 offsetof(EAP_TLS_CONF, certificate_file), NULL, NULL },
51 { "CA_file", PW_TYPE_STRING_PTR,
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);
92 radlog(L_INFO, "WARNING: rlm_eap_tls: Unable to set DH parameters. DH cipher suites may not work!");
93 DEBUG2("WARNING: Fix this by running the OpenSSL command listed in eap.conf");
97 if (SSL_CTX_set_tmp_dh(ctx, dh) < 0) {
98 radlog(L_ERR, "rlm_eap_tls: Unable to set DH parameters");
108 * Generte ephemeral RSA keys.
110 static int generate_eph_rsa_key(SSL_CTX *ctx)
114 rsa = RSA_generate_key(512, RSA_F4, NULL, NULL);
116 if (!SSL_CTX_set_tmp_rsa(ctx, rsa)) {
117 radlog(L_ERR, "rlm_eap_tls: Couldn't set RSA key");
127 * Before trusting a certificate, you must make sure that the
128 * certificate is 'valid'. There are several steps that your
129 * application can take in determining if a certificate is
130 * valid. Commonly used steps are:
132 * 1.Verifying the certificate's signature, and verifying that
133 * the certificate has been issued by a trusted Certificate
136 * 2.Verifying that the certificate is valid for the present date
137 * (i.e. it is being presented within its validity dates).
139 * 3.Verifying that the certificate has not been revoked by its
140 * issuing Certificate Authority, by checking with respect to a
141 * Certificate Revocation List (CRL).
143 * 4.Verifying that the credentials presented by the certificate
144 * fulfill additional requirements specific to the application,
145 * such as with respect to access control lists or with respect
146 * to OCSP (Online Certificate Status Processing).
148 * NOTE: This callback will be called multiple times based on the
149 * depth of the root certificate chain
151 static int cbtls_verify(int ok, X509_STORE_CTX *ctx)
153 char subject[1024]; /* Used for the subject name */
154 char issuer[1024]; /* Used for the issuer name */
155 char common_name[1024];
157 EAP_HANDLER *handler = NULL;
164 client_cert = X509_STORE_CTX_get_current_cert(ctx);
165 err = X509_STORE_CTX_get_error(ctx);
166 depth = X509_STORE_CTX_get_error_depth(ctx);
169 radlog(L_ERR,"--> verify error:num=%d:%s\n",err,
170 X509_verify_cert_error_string(err));
175 * Retrieve the pointer to the SSL of the connection currently treated
176 * and the application specific data stored into the SSL object.
178 ssl = X509_STORE_CTX_get_ex_data(ctx, SSL_get_ex_data_X509_STORE_CTX_idx());
179 handler = (EAP_HANDLER *)SSL_get_ex_data(ssl, 0);
180 conf = (EAP_TLS_CONF *)SSL_get_ex_data(ssl, 1);
183 * Get the Subject & Issuer
185 subject[0] = issuer[0] = '\0';
186 X509_NAME_oneline(X509_get_subject_name(client_cert), subject,
188 X509_NAME_oneline(X509_get_issuer_name(ctx->current_cert), issuer,
191 subject[sizeof(subject) - 1] = '\0';
192 issuer[sizeof(issuer) - 1] = '\0';
195 * Get the Common Name
197 X509_NAME_get_text_by_NID(X509_get_subject_name(client_cert),
198 NID_commonName, common_name, sizeof(common_name));
199 common_name[sizeof(common_name) - 1] = '\0';
201 switch (ctx->error) {
203 case X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT:
204 radlog(L_ERR, "issuer= %s\n", issuer);
206 case X509_V_ERR_CERT_NOT_YET_VALID:
207 case X509_V_ERR_ERROR_IN_CERT_NOT_BEFORE_FIELD:
208 radlog(L_ERR, "notBefore=");
210 ASN1_TIME_print(bio_err, X509_get_notBefore(ctx->current_cert));
213 case X509_V_ERR_CERT_HAS_EXPIRED:
214 case X509_V_ERR_ERROR_IN_CERT_NOT_AFTER_FIELD:
215 radlog(L_ERR, "notAfter=");
217 ASN1_TIME_print(bio_err, X509_get_notAfter(ctx->current_cert));
223 * If we're at the actual client cert, apply additional
228 * If the conf tells us to, check cert issuer
229 * against the specified value and fail
230 * verification if they don't match.
232 if (conf->check_cert_issuer &&
233 (strcmp(issuer, conf->check_cert_issuer) != 0)) {
234 radlog(L_AUTH, "rlm_eap_tls: Certificate issuer (%s) does not match specified value (%s)!", issuer, conf->check_cert_issuer);
239 * If the conf tells us to, check the CN in the
240 * cert against xlat'ed value, but only if the
241 * previous checks passed.
243 if (my_ok && conf->check_cert_cn) {
244 if (!radius_xlat(cn_str, sizeof(cn_str), conf->check_cert_cn, handler->request, NULL)) {
245 radlog(L_ERR, "rlm_eap_tls (%s): xlat failed.",
246 conf->check_cert_cn);
247 /* if this fails, fail the verification */
250 DEBUG2(" rlm_eap_tls: checking certificate CN (%s) with xlat'ed value (%s)", common_name, cn_str);
251 if (strcmp(cn_str, common_name) != 0) {
252 radlog(L_AUTH, "rlm_eap_tls: Certificate CN (%s) does not match specified value (%s)!", common_name, cn_str);
256 } /* check_cert_cn */
259 if (debug_flag > 0) {
260 radlog(L_INFO, "chain-depth=%d, ", depth);
261 radlog(L_INFO, "error=%d", err);
263 radlog(L_INFO, "--> User-Name = %s", handler->identity);
264 radlog(L_INFO, "--> BUF-Name = %s", common_name);
265 radlog(L_INFO, "--> subject = %s", subject);
266 radlog(L_INFO, "--> issuer = %s", issuer);
267 radlog(L_INFO, "--> verify return:%d", my_ok);
274 * Create Global context SSL and use it in every new session
276 * - Load the trusted CAs
277 * - Load the Private key & the certificate
278 * - Set the Context options & Verify options
280 static SSL_CTX *init_tls_ctx(EAP_TLS_CONF *conf)
284 X509_STORE *certstore;
285 int verify_mode = SSL_VERIFY_NONE;
290 * Add all the default ciphers and message digests
291 * Create our context.
294 SSL_load_error_strings();
296 meth = TLSv1_method();
297 ctx = SSL_CTX_new(meth);
300 * Identify the type of certificates that needs to be loaded
302 if (conf->file_type) {
303 type = SSL_FILETYPE_PEM;
305 type = SSL_FILETYPE_ASN1;
309 * Set the password to load private key
311 if (conf->private_key_password) {
312 SSL_CTX_set_default_passwd_cb_userdata(ctx, conf->private_key_password);
313 SSL_CTX_set_default_passwd_cb(ctx, cbtls_password);
317 * Load our keys and certificates
319 * If certificates are of type PEM then we can make use
320 * of cert chain authentication using openssl api call
321 * SSL_CTX_use_certificate_chain_file. Please see how
322 * the cert chain needs to be given in PEM from
325 if (type == SSL_FILETYPE_PEM) {
326 radlog(L_INFO, "rlm_eap_tls: Loading the certificate file as a chain");
327 if (!(SSL_CTX_use_certificate_chain_file(ctx, conf->certificate_file))) {
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 } else if (!(SSL_CTX_use_certificate_file(ctx, conf->certificate_file, type))) {
334 radlog(L_ERR, "rlm_eap: SSL error %s", ERR_error_string(ERR_get_error(), NULL));
335 radlog(L_ERR, "rlm_eap_tls: Error reading certificate file");
340 /* Load the CAs we trust */
341 if (!SSL_CTX_load_verify_locations(ctx, conf->ca_file, conf->ca_path)) {
342 radlog(L_ERR, "rlm_eap: SSL error %s", ERR_error_string(ERR_get_error(), NULL));
343 radlog(L_ERR, "rlm_eap_tls: Error reading Trusted root CA list");
346 SSL_CTX_set_client_CA_list(ctx, SSL_load_client_CA_file(conf->ca_file));
348 if (!(SSL_CTX_use_PrivateKey_file(ctx, conf->private_key_file, type))) {
349 radlog(L_ERR, "rlm_eap: SSL error %s", ERR_error_string(ERR_get_error(), NULL));
350 radlog(L_ERR, "rlm_eap_tls: Error reading private key file");
355 * Check if the loaded private key is the right one
357 if (!SSL_CTX_check_private_key(ctx)) {
358 radlog(L_ERR, "rlm_eap_tls: Private key does not match the certificate public key");
365 ctx_options |= SSL_OP_NO_SSLv2;
366 ctx_options |= SSL_OP_NO_SSLv3;
369 * SSL_OP_SINGLE_DH_USE must be used in order to prevent
370 * small subgroup attacks and forward secrecy. Always
373 * SSL_OP_SINGLE_DH_USE has an impact on the computer
374 * time needed during negotiation, but it is not very
377 * SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS to work around issues
378 * in Windows Vista client.
379 * http://www.openssl.org/~bodo/tls-cbc.txt
380 * http://www.nabble.com/(RADIATOR)-Radiator-Version-3.16-released-t2600070.html
382 ctx_options |= SSL_OP_SINGLE_DH_USE | SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS;
383 SSL_CTX_set_options(ctx, ctx_options);
386 * TODO: Set the RSA & DH
387 * SSL_CTX_set_tmp_rsa_callback(ctx, cbtls_rsa);
388 * SSL_CTX_set_tmp_dh_callback(ctx, cbtls_dh);
392 * set the message callback to identify the type of
393 * message. For every new session, there can be a
394 * different callback argument.
396 * SSL_CTX_set_msg_callback(ctx, cbtls_msg);
399 /* Set Info callback */
400 SSL_CTX_set_info_callback(ctx, cbtls_info);
403 * Check the certificates for revocation.
405 #ifdef X509_V_FLAG_CRL_CHECK
406 if (conf->check_crl) {
407 certstore = SSL_CTX_get_cert_store(ctx);
408 if (certstore == NULL) {
409 radlog(L_ERR, "rlm_eap: SSL error %s", ERR_error_string(ERR_get_error(), NULL));
410 radlog(L_ERR, "rlm_eap_tls: Error reading Certificate Store");
413 X509_STORE_set_flags(certstore, X509_V_FLAG_CRL_CHECK);
419 * Always verify the peer certificate
421 verify_mode |= SSL_VERIFY_PEER;
422 verify_mode |= SSL_VERIFY_FAIL_IF_NO_PEER_CERT;
423 verify_mode |= SSL_VERIFY_CLIENT_ONCE;
424 SSL_CTX_set_verify(ctx, verify_mode, cbtls_verify);
426 if (conf->verify_depth) {
427 SSL_CTX_set_verify_depth(ctx, conf->verify_depth);
430 /* Load randomness */
431 if (!(RAND_load_file(conf->random_file, 1024*1024))) {
432 radlog(L_ERR, "rlm_eap: SSL error %s", ERR_error_string(ERR_get_error(), NULL));
433 radlog(L_ERR, "rlm_eap_tls: Error loading randomness");
438 * Set the cipher list if we were told to
440 if (conf->cipher_list) {
441 if (!SSL_CTX_set_cipher_list(ctx, conf->cipher_list)) {
442 radlog(L_ERR, "rlm_eap_tls: Error setting cipher list");
452 * Detach the EAP-TLS module.
454 static int eaptls_detach(void *arg)
459 inst = (eap_tls_t *) arg;
465 free(conf->certificate_file);
466 free(conf->private_key_file);
467 free(conf->private_key_password);
469 free(conf->random_file);
471 free(conf->check_cert_cn);
472 free(conf->cipher_list);
473 free(conf->check_cert_issuer);
475 memset(conf, 0, sizeof(*conf));
480 if (inst->ctx) SSL_CTX_free(inst->ctx);
490 * Attach the EAP-TLS module.
492 static int eaptls_attach(CONF_SECTION *cs, void **instance)
497 /* Store all these values in the data structure for later references */
498 inst = (eap_tls_t *)malloc(sizeof(*inst));
500 radlog(L_ERR, "rlm_eap_tls: out of memory");
503 memset(inst, 0, sizeof(*inst));
506 * Parse the config file & get all the configured values
508 conf = (EAP_TLS_CONF *)malloc(sizeof(*conf));
511 radlog(L_ERR, "rlm_eap_tls: out of memory");
514 memset(conf, 0, sizeof(*conf));
517 if (cf_section_parse(cs, conf, module_config) < 0) {
526 inst->ctx = init_tls_ctx(conf);
527 if (inst->ctx == NULL) {
532 if (load_dh_params(inst->ctx, conf->dh_file) < 0) {
536 if (generate_eph_rsa_key(inst->ctx) < 0) {
548 * Send an initial eap-tls request to the peer.
550 * Frame eap reply packet.
551 * len = header + type + tls_typedata
552 * tls_typedata = flags(Start (S) bit set, and no data)
554 * Once having received the peer's Identity, the EAP server MUST
555 * respond with an EAP-TLS/Start packet, which is an
556 * EAP-Request packet with EAP-Type=EAP-TLS, the Start (S) bit
557 * set, and no data. The EAP-TLS conversation will then begin,
558 * with the peer sending an EAP-Response packet with
559 * EAP-Type = EAP-TLS. The data field of that packet will
562 * Fragment length is Framed-MTU - 4.
564 * http://mail.frascone.com/pipermail/public/eap/2003-July/001426.html
566 static int eaptls_initiate(void *type_arg, EAP_HANDLER *handler)
572 int client_cert = TRUE;
573 int verify_mode = SSL_VERIFY_NONE;
575 inst = (eap_tls_t *)type_arg;
578 * If we're TTLS or PEAP, then do NOT require a client
581 * FIXME: This should be more configurable.
583 if (handler->eap_type != PW_EAP_TLS) {
584 vp = pairfind(handler->request->config_items,
585 PW_EAP_TLS_REQUIRE_CLIENT_CERT);
589 client_cert = vp->lvalue;
594 * Every new session is started only from EAP-TLS-START.
595 * Before Sending EAP-TLS-START, open a new SSL session.
596 * Create all the required data structures & store them
597 * in Opaque. So that we can use these data structures
598 * when we get the response
600 ssn = eaptls_new_session(inst->ctx, client_cert);
606 * Verify the peer certificate, if asked.
609 DEBUG2(" rlm_eap_tls: Requiring client certificate");
610 verify_mode = SSL_VERIFY_PEER;
611 verify_mode |= SSL_VERIFY_FAIL_IF_NO_PEER_CERT;
612 verify_mode |= SSL_VERIFY_CLIENT_ONCE;
614 SSL_set_verify(ssn->ssl, verify_mode, cbtls_verify);
617 * Create a structure for all the items required to be
618 * verified for each client and set that as opaque data
621 * NOTE: If we want to set each item sepearately then
622 * this index should be global.
624 SSL_set_ex_data(ssn->ssl, 0, (void *)handler);
625 SSL_set_ex_data(ssn->ssl, 1, (void *)inst->conf);
627 ssn->length_flag = inst->conf->include_length;
630 * We use default fragment size, unless the Framed-MTU
631 * tells us it's too big. Note that we do NOT account
632 * for the EAP-TLS headers if conf->fragment_size is
633 * large, because that config item looks to be confusing.
635 * i.e. it should REALLY be called MTU, and the code here
636 * should figure out what that means for TLS fragment size.
637 * asking the administrator to know the internal details
638 * of EAP-TLS in order to calculate fragment sizes is
641 ssn->offset = inst->conf->fragment_size;
642 vp = pairfind(handler->request->packet->vps, PW_FRAMED_MTU);
643 if (vp && ((vp->lvalue - 14) < ssn->offset)) {
645 * Discount the Framed-MTU by:
647 * 4 : EAP header (code + id + length)
648 * 1 : EAP type == EAP-TLS
650 * 4 : EAP-TLS Message length
651 * (even if conf->include_length == 0,
656 ssn->offset = vp->lvalue - 14;
659 handler->opaque = ((void *)ssn);
660 handler->free_opaque = session_free;
662 DEBUG2(" rlm_eap_tls: Initiate");
665 * PEAP-specific breakage.
667 if (handler->eap_type == PW_EAP_PEAP) {
669 * As it is a poorly designed protocol, PEAP uses
670 * bits in the TLS header to indicate PEAP
671 * version numbers. For now, we only support
672 * PEAP version 0, so it doesn't matter too much.
673 * However, if we support later versions of PEAP,
674 * we will need this flag to indicate which
675 * version we're currently dealing with.
677 ssn->peap_flag = 0x00;
680 * PEAP version 0 requires 'include_length = no',
681 * so rather than hoping the user figures it out,
684 ssn->length_flag = 0;
688 * TLS session initialization is over. Now handle TLS
689 * related handshaking or application data.
691 status = eaptls_start(handler->eap_ds, ssn->peap_flag);
692 DEBUG2(" rlm_eap_tls: Start returned %d", status);
697 * The next stage to process the packet.
699 handler->stage = AUTHENTICATE;
705 * Do authentication, by letting EAP-TLS do most of the work.
707 static int eaptls_authenticate(void *arg UNUSED, EAP_HANDLER *handler)
709 eaptls_status_t status;
710 tls_session_t *tls_session = (tls_session_t *) handler->opaque;
712 DEBUG2(" rlm_eap_tls: Authenticate");
714 status = eaptls_process(handler);
715 DEBUG2(" eaptls_process returned %d\n", status);
718 * EAP-TLS handshake was successful, return an
719 * EAP-TLS-Success packet here.
725 * The TLS code is still working on the TLS
726 * exchange, and it's a valid TLS request.
733 * Handshake is done, proceed with decoding tunneled
737 DEBUG2(" rlm_eap_tls: Received unexpected tunneled data after successful handshake.");
739 if (debug_flag > 2) {
741 unsigned int data_len;
742 unsigned char buffer[1024];
744 data_len = (tls_session->record_minus)(&tls_session->dirty_in,
745 buffer, sizeof(buffer));
746 log_debug(" Tunneled data (%u bytes)\n", data_len);
747 for (i = 0; i < data_len; i++) {
748 if ((i & 0x0f) == 0x00) printf(" %x: ", i);
749 if ((i & 0x0f) == 0x0f) printf("\n");
751 printf("%02x ", buffer[i]);
757 eaptls_fail(handler->eap_ds, 0);
762 * Anything else: fail.
769 * Success: Return MPPE keys.
771 eaptls_success(handler->eap_ds, 0);
772 eaptls_gen_mppe_keys(&handler->request->reply->vps,
774 "client EAP encryption");
779 * The module name should be the only globally exported symbol.
780 * That is, everything else should be 'static'.
782 EAP_TYPE rlm_eap_tls = {
784 eaptls_attach, /* attach */
785 eaptls_initiate, /* Start the initial request */
786 NULL, /* authorization */
787 eaptls_authenticate, /* authentication */
788 eaptls_detach /* detach */