2 Bacula® - The Network Backup Solution
4 Copyright (C) 2005-2010 Free Software Foundation Europe e.V.
6 The main author of Bacula is Kern Sibbald, with contributions from
7 many others, a complete list can be found in the file AUTHORS.
8 This program is Free Software; you can redistribute it and/or
9 modify it under the terms of version two of the GNU General Public
10 License as published by the Free Software Foundation and included
13 This program is distributed in the hope that it will be useful, but
14 WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with this program; if not, write to the Free Software
20 Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
23 Bacula® is a registered trademark of Kern Sibbald.
24 The licensor of Bacula is the Free Software Foundation Europe
25 (FSFE), Fiduciary Program, Sumatrastrasse 25, 8006 Zürich,
26 Switzerland, email:ftf@fsfeurope.org.
29 * tls.c TLS support functions
31 * Author: Landon Fuller <landonf@threerings.net>
33 * This file was contributed to the Bacula project by Landon Fuller
34 * and Three Rings Design, Inc.
36 * Three Rings Design, Inc. has been granted a perpetual, worldwide,
37 * non-exclusive, no-charge, royalty-free, irrevocable copyright
38 * license to reproduce, prepare derivative works of, publicly
39 * display, publicly perform, sublicense, and distribute the original
40 * work contributed by Three Rings Design, Inc. and its employees to
41 * the Bacula project in source or object form.
43 * If you wish to license contributions from Three Rings Design, Inc,
44 * under an alternate open source license please contact
45 * Landon Fuller <landonf@threerings.net>.
53 #ifdef HAVE_TLS /* Is TLS enabled? */
55 #ifdef HAVE_OPENSSL /* How about OpenSSL? */
57 /* No anonymous ciphers, no <128 bit ciphers, no export ciphers, no MD5 ciphers */
58 #define TLS_DEFAULT_CIPHERS "ALL:!ADH:!LOW:!EXP:!MD5:@STRENGTH"
60 /* TLS Context Structure */
63 CRYPTO_PEM_PASSWD_CB *pem_callback;
64 const void *pem_userdata;
69 struct TLS_Connection {
74 * OpenSSL certificate verification callback.
75 * OpenSSL has already performed internal certificate verification.
76 * We just report any errors that occured.
78 static int openssl_verify_peer(int ok, X509_STORE_CTX *store)
81 X509 *cert = X509_STORE_CTX_get_current_cert(store);
82 int depth = X509_STORE_CTX_get_error_depth(store);
83 int err = X509_STORE_CTX_get_error(store);
87 X509_NAME_oneline(X509_get_issuer_name(cert), issuer, 256);
88 X509_NAME_oneline(X509_get_subject_name(cert), subject, 256);
90 Jmsg5(NULL, M_ERROR, 0, _("Error with certificate at depth: %d, issuer = %s,"
91 " subject = %s, ERR=%d:%s\n"), depth, issuer,
92 subject, err, X509_verify_cert_error_string(err));
99 /* Dispatch user PEM encryption callbacks */
100 static int tls_pem_callback_dispatch (char *buf, int size, int rwflag, void *userdata)
102 TLS_CONTEXT *ctx = (TLS_CONTEXT *)userdata;
103 return (ctx->pem_callback(buf, size, ctx->pem_userdata));
107 * Create a new TLS_CONTEXT instance.
108 * Returns: Pointer to TLS_CONTEXT instance on success
111 TLS_CONTEXT *new_tls_context(const char *ca_certfile, const char *ca_certdir,
112 const char *certfile, const char *keyfile,
113 CRYPTO_PEM_PASSWD_CB *pem_callback,
114 const void *pem_userdata, const char *dhfile,
121 ctx = (TLS_CONTEXT *)malloc(sizeof(TLS_CONTEXT));
123 /* Allocate our OpenSSL TLSv1 Context */
124 ctx->openssl = SSL_CTX_new(TLSv1_method());
127 openssl_post_errors(M_ERROR, _("Error initializing SSL context"));
131 /* Set up pem encryption callback */
133 ctx->pem_callback = pem_callback;
134 ctx->pem_userdata = pem_userdata;
136 ctx->pem_callback = crypto_default_pem_callback;
137 ctx->pem_userdata = NULL;
139 SSL_CTX_set_default_passwd_cb(ctx->openssl, tls_pem_callback_dispatch);
140 SSL_CTX_set_default_passwd_cb_userdata(ctx->openssl, (void *) ctx);
143 * Set certificate verification paths. This requires that at least one
146 if (ca_certfile || ca_certdir) {
147 if (!SSL_CTX_load_verify_locations(ctx->openssl, ca_certfile, ca_certdir)) {
148 openssl_post_errors(M_ERROR, _("Error loading certificate verification stores"));
151 } else if (verify_peer) {
152 /* At least one CA is required for peer verification */
153 Jmsg0(NULL, M_ERROR, 0, _("Either a certificate file or a directory must be"
154 " specified as a verification store\n"));
159 * Load our certificate file, if available. This file may also contain a
160 * private key, though this usage is somewhat unusual.
163 if (!SSL_CTX_use_certificate_chain_file(ctx->openssl, certfile)) {
164 openssl_post_errors(M_ERROR, _("Error loading certificate file"));
169 /* Load our private key. */
171 if (!SSL_CTX_use_PrivateKey_file(ctx->openssl, keyfile, SSL_FILETYPE_PEM)) {
172 openssl_post_errors(M_ERROR, _("Error loading private key"));
177 /* Load Diffie-Hellman Parameters. */
179 if (!(bio = BIO_new_file(dhfile, "r"))) {
180 openssl_post_errors(M_ERROR, _("Unable to open DH parameters file"));
183 dh = PEM_read_bio_DHparams(bio, NULL, NULL, NULL);
186 openssl_post_errors(M_ERROR, _("Unable to load DH parameters from specified file"));
189 if (!SSL_CTX_set_tmp_dh(ctx->openssl, dh)) {
190 openssl_post_errors(M_ERROR, _("Failed to set TLS Diffie-Hellman parameters"));
194 /* Enable Single-Use DH for Ephemeral Keying */
195 SSL_CTX_set_options(ctx->openssl, SSL_OP_SINGLE_DH_USE);
198 if (SSL_CTX_set_cipher_list(ctx->openssl, TLS_DEFAULT_CIPHERS) != 1) {
199 Jmsg0(NULL, M_ERROR, 0,
200 _("Error setting cipher list, no valid ciphers available\n"));
204 /* Verify Peer Certificate */
206 /* SSL_VERIFY_FAIL_IF_NO_PEER_CERT has no effect in client mode */
207 SSL_CTX_set_verify(ctx->openssl,
208 SSL_VERIFY_PEER|SSL_VERIFY_FAIL_IF_NO_PEER_CERT,
209 openssl_verify_peer);
215 /* Clean up after ourselves */
217 SSL_CTX_free(ctx->openssl);
224 * Free TLS_CONTEXT instance
226 void free_tls_context(TLS_CONTEXT *ctx)
228 SSL_CTX_free(ctx->openssl);
232 bool get_tls_require(TLS_CONTEXT *ctx)
234 return ctx->tls_require;
237 bool get_tls_enable(TLS_CONTEXT *ctx)
239 return ctx->tls_enable;
244 * Verifies a list of common names against the certificate
245 * commonName attribute.
246 * Returns: true on success
249 bool tls_postconnect_verify_cn(JCR *jcr, TLS_CONNECTION *tls, alist *verify_list)
251 SSL *ssl = tls->openssl;
254 bool auth_success = false;
257 /* Check if peer provided a certificate */
258 if (!(cert = SSL_get_peer_certificate(ssl))) {
259 Qmsg0(jcr, M_ERROR, 0, _("Peer failed to present a TLS certificate\n"));
263 if ((subject = X509_get_subject_name(cert)) != NULL) {
264 if (X509_NAME_get_text_by_NID(subject, NID_commonName, data, sizeof(data)) > 0) {
266 /* NULL terminate data */
269 /* Try all the CNs in the list */
270 foreach_alist(cn, verify_list) {
271 if (strcasecmp(data, cn) == 0) {
283 * Verifies a peer's hostname against the subjectAltName and commonName
285 * Returns: true on success
288 bool tls_postconnect_verify_host(JCR *jcr, TLS_CONNECTION *tls, const char *host)
290 SSL *ssl = tls->openssl;
293 bool auth_success = false;
298 X509_NAME_ENTRY *neCN;
301 /* Check if peer provided a certificate */
302 if (!(cert = SSL_get_peer_certificate(ssl))) {
303 Qmsg1(jcr, M_ERROR, 0,
304 _("Peer %s failed to present a TLS certificate\n"), host);
308 /* Check subjectAltName extensions first */
309 if ((extensions = X509_get_ext_count(cert)) > 0) {
310 for (i = 0; i < extensions; i++) {
314 ext = X509_get_ext(cert, i);
315 extname = OBJ_nid2sn(OBJ_obj2nid(X509_EXTENSION_get_object(ext)));
317 if (strcmp(extname, "subjectAltName") == 0) {
318 X509V3_EXT_METHOD *method;
319 STACK_OF(CONF_VALUE) *val;
322 #if (OPENSSL_VERSION_NUMBER >= 0x0090800FL)
323 const unsigned char *ext_value_data;
325 unsigned char *ext_value_data;
328 /* Get x509 extension method structure */
329 if (!(method = X509V3_EXT_get(ext))) {
333 ext_value_data = ext->value->data;
335 #if (OPENSSL_VERSION_NUMBER > 0x00907000L)
339 /* Decode ASN1 item in data */
340 extstr = ASN1_item_d2i(NULL, &ext_value_data, ext->value->length,
341 ASN1_ITEM_ptr(method->it));
345 /* Decode ASN1 item in data */
346 extstr = method->d2i(NULL, &ext_value_data, ext->value->length);
350 extstr = method->d2i(NULL, &ext_value_data, ext->value->length);
353 /* Iterate through to find the dNSName field(s) */
354 val = method->i2v(method, extstr, NULL);
356 /* dNSName shortname is "DNS" */
357 for (j = 0; j < sk_CONF_VALUE_num(val); j++) {
358 nval = sk_CONF_VALUE_value(val, j);
359 if (strcmp(nval->name, "DNS") == 0) {
360 if (strcasecmp(nval->value, host) == 0) {
370 /* Try verifying against the subject name */
372 if ((subject = X509_get_subject_name(cert)) != NULL) {
373 /* Loop through all CNs */
375 cnLastPos = X509_NAME_get_index_by_NID(subject, NID_commonName, cnLastPos);
376 if (cnLastPos == -1) {
379 neCN = X509_NAME_get_entry(subject, cnLastPos);
380 asn1CN = X509_NAME_ENTRY_get_data(neCN);
381 if (strcasecmp((const char*)asn1CN->data, host) == 0) {
396 * Create a new TLS_CONNECTION instance.
398 * Returns: Pointer to TLS_CONNECTION instance on success
401 TLS_CONNECTION *new_tls_connection(TLS_CONTEXT *ctx, int fd)
406 * Create a new BIO and assign the fd.
407 * The caller will remain responsible for closing the associated fd
409 bio = BIO_new(BIO_s_socket());
411 /* Not likely, but never say never */
412 openssl_post_errors(M_ERROR, _("Error creating file descriptor-based BIO"));
413 return NULL; /* Nothing allocated, nothing to clean up */
415 BIO_set_fd(bio, fd, BIO_NOCLOSE);
417 /* Allocate our new tls connection */
418 TLS_CONNECTION *tls = (TLS_CONNECTION *)malloc(sizeof(TLS_CONNECTION));
420 /* Create the SSL object and attach the socket BIO */
421 if ((tls->openssl = SSL_new(ctx->openssl)) == NULL) {
422 /* Not likely, but never say never */
423 openssl_post_errors(M_ERROR, _("Error creating new SSL object"));
427 SSL_set_bio(tls->openssl, bio, bio);
429 /* Non-blocking partial writes */
430 SSL_set_mode(tls->openssl, SSL_MODE_ENABLE_PARTIAL_WRITE|SSL_MODE_ACCEPT_MOVING_WRITE_BUFFER);
437 SSL_free(tls->openssl);
443 * Free TLS_CONNECTION instance
445 void free_tls_connection(TLS_CONNECTION *tls)
447 SSL_free(tls->openssl);
451 /* Does all the manual labor for tls_bsock_accept() and tls_bsock_connect() */
452 static inline bool openssl_bsock_session_start(BSOCK *bsock, bool server)
454 TLS_CONNECTION *tls = bsock->tls;
461 /* Zero the fdset, we'll set our fd prior to each invocation of select() */
463 fdmax = bsock->m_fd + 1;
465 /* Ensure that socket is non-blocking */
466 flags = bsock->set_nonblocking();
469 bsock->timer_start = watchdog_time;
470 bsock->clear_timed_out();
474 err = SSL_accept(tls->openssl);
476 err = SSL_connect(tls->openssl);
480 switch (SSL_get_error(tls->openssl, err)) {
484 case SSL_ERROR_ZERO_RETURN:
485 /* TLS connection was cleanly shut down */
486 openssl_post_errors(M_ERROR, _("Connect failure"));
489 case SSL_ERROR_WANT_READ:
490 /* If we timeout of a select, this will be unset */
491 FD_SET((unsigned) bsock->m_fd, &fdset);
492 /* Set our timeout */
495 /* Block until we can read */
496 select(fdmax, &fdset, NULL, NULL, &tv);
498 case SSL_ERROR_WANT_WRITE:
499 /* If we timeout of a select, this will be unset */
500 FD_SET((unsigned) bsock->m_fd, &fdset);
501 /* Set our timeout */
504 /* Block until we can write */
505 select(fdmax, NULL, &fdset, NULL, &tv);
508 /* Socket Error Occurred */
509 openssl_post_errors(M_ERROR, _("Connect failure"));
514 if (bsock->is_timed_out()) {
520 /* Restore saved flags */
521 bsock->restore_blocking(flags);
523 bsock->timer_start = 0;
529 * Initiates a TLS connection with the server.
530 * Returns: true on success
533 bool tls_bsock_connect(BSOCK *bsock)
535 /* SSL_connect(bsock->tls) */
536 return openssl_bsock_session_start(bsock, false);
540 * Listens for a TLS connection from a client.
541 * Returns: true on success
544 bool tls_bsock_accept(BSOCK *bsock)
546 /* SSL_accept(bsock->tls) */
547 return openssl_bsock_session_start(bsock, true);
551 * Shutdown TLS_CONNECTION instance
553 void tls_bsock_shutdown(BSOCK *bsock)
556 * SSL_shutdown must be called twice to fully complete the process -
557 * The first time to initiate the shutdown handshake, and the second to
558 * receive the peer's reply.
560 * In addition, if the underlying socket is blocking, SSL_shutdown()
561 * will not return until the current stage of the shutdown process has
562 * completed or an error has occured. By setting the socket blocking
563 * we can avoid the ugly for()/switch()/select() loop.
569 /* Set socket blocking for shutdown */
570 bsock->set_blocking();
572 tid = start_bsock_timer(bsock, 60 * 2);
573 err = SSL_shutdown(bsock->tls->openssl);
574 stop_bsock_timer(tid);
576 /* Complete shutdown */
577 tid = start_bsock_timer(bsock, 60 * 2);
578 err = SSL_shutdown(bsock->tls->openssl);
579 stop_bsock_timer(tid);
583 switch (SSL_get_error(bsock->tls->openssl, err)) {
586 case SSL_ERROR_ZERO_RETURN:
587 /* TLS connection was shut down on us via a TLS protocol-level closure */
588 openssl_post_errors(M_ERROR, _("TLS shutdown failure."));
591 /* Socket Error Occurred */
592 openssl_post_errors(M_ERROR, _("TLS shutdown failure."));
597 /* Does all the manual labor for tls_bsock_readn() and tls_bsock_writen() */
598 static inline int openssl_bsock_readwrite(BSOCK *bsock, char *ptr, int nbytes, bool write)
600 TLS_CONNECTION *tls = bsock->tls;
607 /* Zero the fdset, we'll set our fd prior to each invocation of select() */
609 fdmax = bsock->m_fd + 1;
611 /* Ensure that socket is non-blocking */
612 flags = bsock->set_nonblocking();
615 bsock->timer_start = watchdog_time;
616 bsock->clear_timed_out();
622 nwritten = SSL_write(tls->openssl, ptr, nleft);
624 nwritten = SSL_read(tls->openssl, ptr, nleft);
628 switch (SSL_get_error(tls->openssl, nwritten)) {
636 case SSL_ERROR_WANT_READ:
637 /* If we timeout on a select, this will be unset */
638 FD_SET((unsigned)bsock->m_fd, &fdset);
641 /* Block until we can read */
642 select(fdmax, &fdset, NULL, NULL, &tv);
645 case SSL_ERROR_WANT_WRITE:
646 /* If we timeout on a select, this will be unset */
647 FD_SET((unsigned)bsock->m_fd, &fdset);
650 /* Block until we can write */
651 select(fdmax, NULL, &fdset, NULL, &tv);
654 case SSL_ERROR_ZERO_RETURN:
655 /* TLS connection was cleanly shut down */
656 /* Fall through wanted */
658 /* Socket Error Occured */
659 openssl_post_errors(M_ERROR, _("TLS read/write failure."));
663 /* Everything done? */
668 /* Timeout/Termination, let's take what we can get */
669 if (bsock->is_timed_out() || bsock->is_terminated()) {
675 /* Restore saved flags */
676 bsock->restore_blocking(flags);
679 bsock->timer_start = 0;
680 return nbytes - nleft;
684 int tls_bsock_writen(BSOCK *bsock, char *ptr, int32_t nbytes)
686 /* SSL_write(bsock->tls->openssl, ptr, nbytes) */
687 return openssl_bsock_readwrite(bsock, ptr, nbytes, true);
690 int tls_bsock_readn(BSOCK *bsock, char *ptr, int32_t nbytes)
692 /* SSL_read(bsock->tls->openssl, ptr, nbytes) */
693 return openssl_bsock_readwrite(bsock, ptr, nbytes, false);
696 #else /* HAVE_OPENSSL */
697 # error No TLS implementation available.
698 #endif /* !HAVE_OPENSSL */
701 #else /* TLS NOT enabled, dummy routines substituted */
705 TLS_CONTEXT *new_tls_context(const char *ca_certfile, const char *ca_certdir,
706 const char *certfile, const char *keyfile,
707 CRYPTO_PEM_PASSWD_CB *pem_callback,
708 const void *pem_userdata, const char *dhfile,
713 void free_tls_context(TLS_CONTEXT *ctx) { }
715 void tls_bsock_shutdown(BSOCK *bsock) { }
717 void free_tls_connection(TLS_CONNECTION *tls) { }
719 bool get_tls_require(TLS_CONTEXT *ctx)
724 bool get_tls_enable(TLS_CONTEXT *ctx)
729 #endif /* HAVE_TLS */