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},
70 { NULL, -1, 0, NULL, NULL } /* end the list */
75 * TODO: Check for the type of key exchange * like conf->dh_key
77 static int load_dh_params(SSL_CTX *ctx, char *file)
82 if ((bio = BIO_new_file(file, "r")) == NULL) {
83 radlog(L_ERR, "rlm_eap_tls: Unable to open DH file - %s", file);
87 dh = PEM_read_bio_DHparams(bio, NULL, NULL, NULL);
89 if (SSL_CTX_set_tmp_dh(ctx, dh) < 0) {
90 radlog(L_ERR, "rlm_eap_tls: Unable to set DH parameters");
100 * Generte ephemeral RSA keys.
102 static int generate_eph_rsa_key(SSL_CTX *ctx)
106 rsa = RSA_generate_key(512, RSA_F4, NULL, NULL);
108 if (!SSL_CTX_set_tmp_rsa(ctx, rsa)) {
109 radlog(L_ERR, "rlm_eap_tls: Couldn't set RSA key");
119 * Before trusting a certificate, you must make sure that the
120 * certificate is 'valid'. There are several steps that your
121 * application can take in determining if a certificate is
122 * valid. Commonly used steps are:
124 * 1.Verifying the certificate's signature, and verifying that
125 * the certificate has been issued by a trusted Certificate
128 * 2.Verifying that the certificate is valid for the present date
129 * (i.e. it is being presented within its validity dates).
131 * 3.Verifying that the certificate has not been revoked by its
132 * issuing Certificate Authority, by checking with respect to a
133 * Certificate Revocation List (CRL).
135 * 4.Verifying that the credentials presented by the certificate
136 * fulfill additional requirements specific to the application,
137 * such as with respect to access control lists or with respect
138 * to OCSP (Online Certificate Status Processing).
140 * NOTE: This callback will be called multiple times based on the
141 * depth of the root certificate chain
143 static int cbtls_verify(int ok, X509_STORE_CTX *ctx)
145 char subject[256]; /* Used for the subject name */
146 char issuer[256]; /* Used for the issuer name */
149 EAP_HANDLER *handler = NULL;
156 client_cert = X509_STORE_CTX_get_current_cert(ctx);
157 err = X509_STORE_CTX_get_error(ctx);
158 depth = X509_STORE_CTX_get_error_depth(ctx);
161 radlog(L_ERR,"--> verify error:num=%d:%s\n",err,
162 X509_verify_cert_error_string(err));
166 * Catch too long Certificate chains
170 * Retrieve the pointer to the SSL of the connection currently treated
171 * and the application specific data stored into the SSL object.
173 ssl = X509_STORE_CTX_get_ex_data(ctx, SSL_get_ex_data_X509_STORE_CTX_idx());
174 handler = (EAP_HANDLER *)SSL_get_ex_data(ssl, 0);
175 conf = (EAP_TLS_CONF *)SSL_get_ex_data(ssl, 1);
178 * Get the Subject & Issuer
180 subject[0] = issuer[0] = '\0';
181 X509_NAME_oneline(X509_get_subject_name(client_cert), subject, 256);
182 X509_NAME_oneline(X509_get_issuer_name(ctx->current_cert), issuer, 256);
185 * Get the Common Name
187 X509_NAME_get_text_by_NID(X509_get_subject_name(client_cert),
188 NID_commonName, buf, 256);
190 switch (ctx->error) {
192 case X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT:
193 radlog(L_ERR, "issuer= %s\n", issuer);
195 case X509_V_ERR_CERT_NOT_YET_VALID:
196 case X509_V_ERR_ERROR_IN_CERT_NOT_BEFORE_FIELD:
197 radlog(L_ERR, "notBefore=");
199 ASN1_TIME_print(bio_err, X509_get_notBefore(ctx->current_cert));
202 case X509_V_ERR_CERT_HAS_EXPIRED:
203 case X509_V_ERR_ERROR_IN_CERT_NOT_AFTER_FIELD:
204 radlog(L_ERR, "notAfter=");
206 ASN1_TIME_print(bio_err, X509_get_notAfter(ctx->current_cert));
212 * If we're at the actual client cert and the conf tells
213 * us to, check the CN in the cert against the xlat'ed
216 if (depth == 0 && conf->check_cert_cn != NULL) {
217 if (!radius_xlat(cn_str, sizeof(cn_str), conf->check_cert_cn, handler->request, NULL)) {
218 radlog(L_ERR, "rlm_eap_tls (%s): xlat failed.",
219 conf->check_cert_cn);
220 /* if this fails, fail the verification */
223 DEBUG2(" rlm_eap_tls: checking certificate CN (%s) with xlat'ed value (%s)", buf, cn_str);
224 if (strncmp(cn_str, buf, sizeof(buf)) != 0) {
226 radlog(L_AUTH, "rlm_eap_tls: Certificate CN (%s) does not match specified value (%s)!", buf, cn_str);
230 if (debug_flag > 0) {
231 radlog(L_INFO, "chain-depth=%d, ", depth);
237 radlog(L_INFO, "error=%d", err);
239 radlog(L_INFO, "--> User-Name = %s", handler->identity);
240 radlog(L_INFO, "--> BUF-Name = %s", buf);
241 radlog(L_INFO, "--> subject = %s", subject);
242 radlog(L_INFO, "--> issuer = %s", issuer);
243 radlog(L_INFO, "--> verify return:%d", my_ok);
250 * Create Global context SSL and use it in every new session
252 * - Load the trusted CAs
253 * - Load the Private key & the certificate
254 * - Set the Context options & Verify options
256 static SSL_CTX *init_tls_ctx(EAP_TLS_CONF *conf)
260 X509_STORE *certstore;
261 int verify_mode = SSL_VERIFY_NONE;
266 * Add all the default ciphers and message digests
267 * Create our context.
270 SSL_load_error_strings();
272 meth = TLSv1_method();
273 ctx = SSL_CTX_new(meth);
276 * Identify the type of certificates that needs to be loaded
278 if (conf->file_type) {
279 type = SSL_FILETYPE_PEM;
281 type = SSL_FILETYPE_ASN1;
285 * Set the password to load private key
287 if (conf->private_key_password) {
288 SSL_CTX_set_default_passwd_cb_userdata(ctx, conf->private_key_password);
289 SSL_CTX_set_default_passwd_cb(ctx, cbtls_password);
293 * Load our keys and certificates
295 * If certificates are of type PEM then we can make use
296 * of cert chain authentication using openssl api call
297 * SSL_CTX_use_certificate_chain_file. Please see how
298 * the cert chain needs to be given in PEM from
301 if (type == SSL_FILETYPE_PEM) {
302 radlog(L_INFO, "rlm_eap_tls: Loading the certificate file as a chain");
303 if (!(SSL_CTX_use_certificate_chain_file(ctx, conf->certificate_file))) {
304 radlog(L_ERR, "rlm_eap: SSL error %s", ERR_error_string(ERR_get_error(), NULL));
305 radlog(L_ERR, "rlm_eap_tls: Error reading certificate file");
309 } else if (!(SSL_CTX_use_certificate_file(ctx, conf->certificate_file, type))) {
310 radlog(L_ERR, "rlm_eap: SSL error %s", ERR_error_string(ERR_get_error(), NULL));
311 radlog(L_ERR, "rlm_eap_tls: Error reading certificate file");
315 /* Load the CAs we trust */
316 if (!SSL_CTX_load_verify_locations(ctx, conf->ca_file, conf->ca_path)) {
317 radlog(L_ERR, "rlm_eap: SSL error %s", ERR_error_string(ERR_get_error(), NULL));
318 radlog(L_ERR, "rlm_eap_tls: Error reading Trusted root CA list");
321 SSL_CTX_set_client_CA_list(ctx, SSL_load_client_CA_file(conf->ca_file));
322 if (!(SSL_CTX_use_PrivateKey_file(ctx, conf->private_key_file, type))) {
323 radlog(L_ERR, "rlm_eap: SSL error %s", ERR_error_string(ERR_get_error(), NULL));
324 radlog(L_ERR, "rlm_eap_tls: Error reading private key file");
329 * Check if the loaded private key is the right one
331 if (!SSL_CTX_check_private_key(ctx)) {
332 radlog(L_ERR, "rlm_eap_tls: Private key does not match the certificate public key");
339 ctx_options |= SSL_OP_NO_SSLv2;
340 ctx_options |= SSL_OP_NO_SSLv3;
343 * SSL_OP_SINGLE_DH_USE must be used in order to prevent
344 * small subgroup attacks and forward secrecy. Always
347 * SSL_OP_SINGLE_DH_USE has an impact on the computer
348 * time needed during negotiation, but it is not very
351 ctx_options |= SSL_OP_SINGLE_DH_USE;
352 SSL_CTX_set_options(ctx, ctx_options);
355 * TODO: Set the RSA & DH
356 * SSL_CTX_set_tmp_rsa_callback(ctx, cbtls_rsa);
357 * SSL_CTX_set_tmp_dh_callback(ctx, cbtls_dh);
361 * set the message callback to identify the type of
362 * message. For every new session, there can be a
363 * different callback argument.
365 * SSL_CTX_set_msg_callback(ctx, cbtls_msg);
368 /* Set Info callback */
369 SSL_CTX_set_info_callback(ctx, cbtls_info);
372 * Check the certificates for revocation.
374 #ifdef X509_V_FLAG_CRL_CHECK
375 if (conf->check_crl) {
376 certstore = SSL_CTX_get_cert_store(ctx);
377 if (certstore == NULL) {
378 radlog(L_ERR, "rlm_eap: SSL error %s", ERR_error_string(ERR_get_error(), NULL));
379 radlog(L_ERR, "rlm_eap_tls: Error reading Certificate Store");
382 X509_STORE_set_flags(certstore, X509_V_FLAG_CRL_CHECK);
388 * Always verify the peer certificate
390 verify_mode |= SSL_VERIFY_PEER;
391 verify_mode |= SSL_VERIFY_FAIL_IF_NO_PEER_CERT;
392 verify_mode |= SSL_VERIFY_CLIENT_ONCE;
393 SSL_CTX_set_verify(ctx, verify_mode, cbtls_verify);
395 if (conf->verify_depth) {
396 SSL_CTX_set_verify_depth(ctx, conf->verify_depth);
399 /* Load randomness */
400 if (!(RAND_load_file(conf->random_file, 1024*1024))) {
401 radlog(L_ERR, "rlm_eap: SSL error %s", ERR_error_string(ERR_get_error(), NULL));
402 radlog(L_ERR, "rlm_eap_tls: Error loading randomness");
407 * Set the cipher list if we were told to
409 if (conf->cipher_list) {
410 if (!SSL_CTX_set_cipher_list(ctx, conf->cipher_list)) {
411 radlog(L_ERR, "rlm_eap_tls: Error setting cipher list");
421 * Detach the EAP-TLS module.
423 static int eaptls_detach(void *arg)
428 inst = (eap_tls_t *) arg;
432 if (conf->dh_file) free(conf->dh_file);
433 conf->dh_file = NULL;
434 if (conf->certificate_file) free(conf->certificate_file);
435 conf->certificate_file = NULL;
436 if (conf->private_key_file) free(conf->private_key_file);
437 conf->private_key_file = NULL;
438 if (conf->private_key_password) free(conf->private_key_password);
439 conf->private_key_password = NULL;
440 if (conf->random_file) free(conf->random_file);
441 conf->random_file = NULL;
447 if (inst->ctx) SSL_CTX_free(inst->ctx);
457 * Attach the EAP-TLS module.
459 static int eaptls_attach(CONF_SECTION *cs, void **instance)
464 /* Store all these values in the data structure for later references */
465 inst = (eap_tls_t *)malloc(sizeof(*inst));
467 radlog(L_ERR, "rlm_eap_tls: out of memory");
470 memset(inst, 0, sizeof(*inst));
473 * Parse the config file & get all the configured values
475 conf = (EAP_TLS_CONF *)malloc(sizeof(*conf));
477 radlog(L_ERR, "rlm_eap_tls: out of memory");
480 memset(conf, 0, sizeof(*conf));
483 if (cf_section_parse(cs, conf, module_config) < 0) {
492 inst->ctx = init_tls_ctx(conf);
493 if (inst->ctx == NULL) {
498 if (load_dh_params(inst->ctx, conf->dh_file) < 0) {
502 if (generate_eph_rsa_key(inst->ctx) < 0) {
514 * Send an initial eap-tls request to the peer.
516 * Frame eap reply packet.
517 * len = header + type + tls_typedata
518 * tls_typedata = flags(Start (S) bit set, and no data)
520 * Once having received the peer's Identity, the EAP server MUST
521 * respond with an EAP-TLS/Start packet, which is an
522 * EAP-Request packet with EAP-Type=EAP-TLS, the Start (S) bit
523 * set, and no data. The EAP-TLS conversation will then begin,
524 * with the peer sending an EAP-Response packet with
525 * EAP-Type = EAP-TLS. The data field of that packet will
528 * Fragment length is Framed-MTU - 4.
530 * http://mail.frascone.com/pipermail/public/eap/2003-July/001426.html
532 static int eaptls_initiate(void *type_arg, EAP_HANDLER *handler)
538 int client_cert = TRUE;
541 inst = (eap_tls_t *)type_arg;
544 * If we're TTLS or PEAP, then do NOT require a client
547 * FIXME: This should be more configurable.
549 if (handler->eap_type != PW_EAP_TLS) {
550 vp = pairfind(handler->request->config_items,
551 PW_EAP_TLS_REQUIRE_CLIENT_CERT);
555 client_cert = vp->lvalue;
560 * Every new session is started only from EAP-TLS-START.
561 * Before Sending EAP-TLS-START, open a new SSL session.
562 * Create all the required data structures & store them
563 * in Opaque. So that we can use these data structures
564 * when we get the response
566 ssn = eaptls_new_session(inst->ctx, client_cert);
572 * Verify the peer certificate, if asked.
575 DEBUG2(" rlm_eap_tls: Requiring client certificate");
576 verify_mode = SSL_VERIFY_PEER;
577 verify_mode |= SSL_VERIFY_FAIL_IF_NO_PEER_CERT;
578 verify_mode |= SSL_VERIFY_CLIENT_ONCE;
580 SSL_set_verify(ssn->ssl, verify_mode, cbtls_verify);
583 * Create a structure for all the items required to be
584 * verified for each client and set that as opaque data
587 * NOTE: If we want to set each item sepearately then
588 * this index should be global.
590 SSL_set_ex_data(ssn->ssl, 0, (void *)handler);
591 SSL_set_ex_data(ssn->ssl, 1, (void *)inst->conf);
593 ssn->length_flag = inst->conf->include_length;
596 * We set a default fragment size, unless the Framed-MTU
597 * tells us it's too big.
599 ssn->offset = inst->conf->fragment_size;
600 vp = pairfind(handler->request->packet->vps, PW_FRAMED_MTU);
601 if (vp && ((vp->lvalue - 4) < ssn->offset)) {
602 ssn->offset = vp->lvalue - 4;
605 handler->opaque = ((void *)ssn);
606 handler->free_opaque = session_free;
608 DEBUG2(" rlm_eap_tls: Initiate");
611 * PEAP-specific breakage.
613 if (handler->eap_type == PW_EAP_PEAP) {
615 * As it is a poorly designed protocol, PEAP uses
616 * bits in the TLS header to indicate PEAP
617 * version numbers. For now, we only support
618 * PEAP version 0, so it doesn't matter too much.
619 * However, if we support later versions of PEAP,
620 * we will need this flag to indicate which
621 * version we're currently dealing with.
623 ssn->peap_flag = 0x00;
626 * PEAP version 0 requires 'include_length = no',
627 * so rather than hoping the user figures it out,
630 ssn->length_flag = 0;
634 * TLS session initialization is over. Now handle TLS
635 * related handshaking or application data.
637 status = eaptls_start(handler->eap_ds, ssn->peap_flag);
638 DEBUG2(" rlm_eap_tls: Start returned %d", status);
643 * The next stage to process the packet.
645 handler->stage = AUTHENTICATE;
651 * Do authentication, by letting EAP-TLS do most of the work.
653 static int eaptls_authenticate(void *arg UNUSED, EAP_HANDLER *handler)
655 eaptls_status_t status;
656 tls_session_t *tls_session = (tls_session_t *) handler->opaque;
658 DEBUG2(" rlm_eap_tls: Authenticate");
660 status = eaptls_process(handler);
661 DEBUG2(" eaptls_process returned %d\n", status);
664 * EAP-TLS handshake was successful, return an
665 * EAP-TLS-Success packet here.
671 * The TLS code is still working on the TLS
672 * exchange, and it's a valid TLS request.
679 * Handshake is done, proceed with decoding tunneled
683 DEBUG2(" rlm_eap_tls: Received unexpected tunneled data after successful handshake.");
685 if (debug_flag > 2) {
687 unsigned int data_len;
688 unsigned char buffer[1024];
690 data_len = (tls_session->record_minus)(&tls_session->dirty_in,
691 buffer, sizeof(buffer));
692 log_debug(" Tunneled data (%u bytes)\n", data_len);
693 for (i = 0; i < data_len; i++) {
694 if ((i & 0x0f) == 0x00) printf(" %x: ", i);
695 if ((i & 0x0f) == 0x0f) printf("\n");
697 printf("%02x ", buffer[i]);
703 eaptls_fail(handler->eap_ds, 0);
708 * Anything else: fail.
715 * Success: Return MPPE keys.
717 eaptls_success(handler->eap_ds, 0);
718 eaptls_gen_mppe_keys(&handler->request->reply->vps,
720 "client EAP encryption");
725 * The module name should be the only globally exported symbol.
726 * That is, everything else should be 'static'.
728 EAP_TYPE rlm_eap_tls = {
730 eaptls_attach, /* attach */
731 eaptls_initiate, /* Start the initial request */
732 NULL, /* authorization */
733 eaptls_authenticate, /* authentication */
734 eaptls_detach /* detach */