2 * Copyright (c) 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015 Nicira, Inc.
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at:
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
18 #include "stream-ssl.h"
24 #include <sys/types.h>
25 #include <sys/socket.h>
26 #include <netinet/tcp.h>
27 #include <openssl/err.h>
28 #include <openssl/rand.h>
29 #include <openssl/ssl.h>
30 #include <openssl/x509v3.h>
36 #include "dynamic-string.h"
39 #include "openflow/openflow.h"
41 #include "poll-loop.h"
43 #include "socket-util.h"
45 #include "stream-provider.h"
48 #include "openvswitch/vlog.h"
51 /* Ref: https://www.openssl.org/support/faq.html#PROG2
52 * Your application must link against the same version of the Win32 C-Runtime
53 * against which your openssl libraries were linked. The default version for
54 * OpenSSL is /MD - "Multithreaded DLL". If we compile Open vSwitch with
55 * something other than /MD, instead of re-compiling OpenSSL
56 * toolkit, openssl/applink.c can be #included. Also, it is important
57 * to add CRYPTO_malloc_init prior first call to OpenSSL.
59 * XXX: The behavior of the following #include when Open vSwitch is
60 * compiled with /MD is not tested. */
61 #include <openssl/applink.c>
62 #define SHUT_RDWR SD_BOTH
65 VLOG_DEFINE_THIS_MODULE(stream_ssl);
83 enum session_type type;
87 unsigned int session_nr;
89 /* rx_want and tx_want record the result of the last call to SSL_read()
90 * and SSL_write(), respectively:
92 * - If the call reported that data needed to be read from the file
93 * descriptor, the corresponding member is set to SSL_READING.
95 * - If the call reported that data needed to be written to the file
96 * descriptor, the corresponding member is set to SSL_WRITING.
98 * - Otherwise, the member is set to SSL_NOTHING, indicating that the
99 * call completed successfully (or with an error) and that there is no
102 * These are needed because there is no way to ask OpenSSL what a data read
103 * or write would require without giving it a buffer to receive into or
104 * data to send, respectively. (Note that the SSL_want() status is
105 * overwritten by each SSL_read() or SSL_write() call, so we can't rely on
108 * A single call to SSL_read() or SSL_write() can perform both reading
109 * and writing and thus invalidate not one of these values but actually
110 * both. Consider this situation, for example:
112 * - SSL_write() blocks on a read, so tx_want gets SSL_READING.
114 * - SSL_read() laters succeeds reading from 'fd' and clears out the
115 * whole receive buffer, so rx_want gets SSL_READING.
117 * - Client calls stream_wait(STREAM_RECV) and stream_wait(STREAM_SEND)
120 * - Now we're stuck blocking until the peer sends us data, even though
121 * SSL_write() could now succeed, which could easily be a deadlock
124 * On the other hand, we can't reset both tx_want and rx_want on every call
125 * to SSL_read() or SSL_write(), because that would produce livelock,
126 * e.g. in this situation:
128 * - SSL_write() blocks, so tx_want gets SSL_READING or SSL_WRITING.
130 * - SSL_read() blocks, so rx_want gets SSL_READING or SSL_WRITING,
131 * but tx_want gets reset to SSL_NOTHING.
133 * - Client calls stream_wait(STREAM_RECV) and stream_wait(STREAM_SEND)
136 * - Client wakes up immediately since SSL_NOTHING in tx_want indicates
137 * that no blocking is necessary.
139 * The solution we adopt here is to set tx_want to SSL_NOTHING after
140 * calling SSL_read() only if the SSL state of the connection changed,
141 * which indicates that an SSL-level renegotiation made some progress, and
142 * similarly for rx_want and SSL_write(). This prevents both the
143 * deadlock and livelock situations above.
145 int rx_want, tx_want;
147 /* A few bytes of header data in case SSL negotiation fails. */
152 /* SSL context created by ssl_init(). */
155 struct ssl_config_file {
156 bool read; /* Whether the file was successfully read. */
157 char *file_name; /* Configured file name, if any. */
158 struct timespec mtime; /* File mtime as of last time we read it. */
161 /* SSL configuration files. */
162 static struct ssl_config_file private_key;
163 static struct ssl_config_file certificate;
164 static struct ssl_config_file ca_cert;
166 /* Ordinarily, the SSL client and server verify each other's certificates using
167 * a CA certificate. Setting this to false disables this behavior. (This is a
169 static bool verify_peer_cert = true;
171 /* Ordinarily, we require a CA certificate for the peer to be locally
172 * available. We can, however, bootstrap the CA certificate from the peer at
173 * the beginning of our first connection then use that certificate on all
174 * subsequent connections, saving it to a file for use in future runs also. In
175 * this case, 'bootstrap_ca_cert' is true. */
176 static bool bootstrap_ca_cert;
178 /* Session number. Used in debug logging messages to uniquely identify a
180 static unsigned int next_session_nr;
182 /* Who knows what can trigger various SSL errors, so let's throttle them down
184 static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(10, 25);
186 static int ssl_init(void);
187 static int do_ssl_init(void);
188 static bool ssl_wants_io(int ssl_error);
189 static void ssl_close(struct stream *);
190 static void ssl_clear_txbuf(struct ssl_stream *);
191 static void interpret_queued_ssl_error(const char *function);
192 static int interpret_ssl_error(const char *function, int ret, int error,
194 static DH *tmp_dh_callback(SSL *ssl, int is_export OVS_UNUSED, int keylength);
195 static void log_ca_cert(const char *file_name, X509 *cert);
196 static void stream_ssl_set_ca_cert_file__(const char *file_name,
197 bool bootstrap, bool force);
198 static void ssl_protocol_cb(int write_p, int version, int content_type,
199 const void *, size_t, SSL *, void *sslv_);
200 static bool update_ssl_config(struct ssl_config_file *, const char *file_name);
201 static int sock_errno(void);
204 want_to_poll_events(int want)
222 new_ssl_stream(const char *name, int fd, enum session_type type,
223 enum ssl_state state, struct stream **streamp)
225 struct ssl_stream *sslv;
229 /* Check for all the needful configuration. */
231 if (!private_key.read) {
232 VLOG_ERR("Private key must be configured to use SSL");
233 retval = ENOPROTOOPT;
235 if (!certificate.read) {
236 VLOG_ERR("Certificate must be configured to use SSL");
237 retval = ENOPROTOOPT;
239 if (!ca_cert.read && verify_peer_cert && !bootstrap_ca_cert) {
240 VLOG_ERR("CA certificate must be configured to use SSL");
241 retval = ENOPROTOOPT;
243 if (!retval && !SSL_CTX_check_private_key(ctx)) {
244 VLOG_ERR("Private key does not match certificate public key: %s",
245 ERR_error_string(ERR_get_error(), NULL));
246 retval = ENOPROTOOPT;
253 * On windows platforms, this can only be called upon TCP connected.
255 if (state == STATE_SSL_CONNECTING) {
256 setsockopt_tcp_nodelay(fd);
259 /* Create and configure OpenSSL stream. */
262 VLOG_ERR("SSL_new: %s", ERR_error_string(ERR_get_error(), NULL));
263 retval = ENOPROTOOPT;
266 if (SSL_set_fd(ssl, fd) == 0) {
267 VLOG_ERR("SSL_set_fd: %s", ERR_error_string(ERR_get_error(), NULL));
268 retval = ENOPROTOOPT;
271 if (!verify_peer_cert || (bootstrap_ca_cert && type == CLIENT)) {
272 SSL_set_verify(ssl, SSL_VERIFY_NONE, NULL);
275 /* Create and return the ssl_stream. */
276 sslv = xmalloc(sizeof *sslv);
277 stream_init(&sslv->stream, &ssl_stream_class, EAGAIN, name);
283 sslv->rx_want = sslv->tx_want = SSL_NOTHING;
284 sslv->session_nr = next_session_nr++;
287 if (VLOG_IS_DBG_ENABLED()) {
288 SSL_set_msg_callback(ssl, ssl_protocol_cb);
289 SSL_set_msg_callback_arg(ssl, sslv);
292 *streamp = &sslv->stream;
303 static struct ssl_stream *
304 ssl_stream_cast(struct stream *stream)
306 stream_assert_class(stream, &ssl_stream_class);
307 return CONTAINER_OF(stream, struct ssl_stream, stream);
311 ssl_open(const char *name, char *suffix, struct stream **streamp, uint8_t dscp)
320 error = inet_open_active(SOCK_STREAM, suffix, OFP_PORT, NULL, &fd,
323 int state = error ? STATE_TCP_CONNECTING : STATE_SSL_CONNECTING;
324 return new_ssl_stream(name, fd, CLIENT, state, streamp);
326 VLOG_ERR("%s: connect: %s", name, ovs_strerror(error));
332 do_ca_cert_bootstrap(struct stream *stream)
334 struct ssl_stream *sslv = ssl_stream_cast(stream);
335 STACK_OF(X509) *chain;
341 chain = SSL_get_peer_cert_chain(sslv->ssl);
342 if (!chain || !sk_X509_num(chain)) {
343 VLOG_ERR("could not bootstrap CA cert: no certificate presented by "
347 cert = sk_X509_value(chain, sk_X509_num(chain) - 1);
349 /* Check that 'cert' is self-signed. Otherwise it is not a CA
350 * certificate and we should not attempt to use it as one. */
351 error = X509_check_issued(cert, cert);
353 VLOG_ERR("could not bootstrap CA cert: obtained certificate is "
354 "not self-signed (%s)",
355 X509_verify_cert_error_string(error));
356 if (sk_X509_num(chain) < 2) {
357 VLOG_ERR("only one certificate was received, so probably the peer "
358 "is not configured to send its CA certificate");
363 fd = open(ca_cert.file_name, O_CREAT | O_EXCL | O_WRONLY, 0444);
365 if (errno == EEXIST) {
366 VLOG_INFO_RL(&rl, "reading CA cert %s created by another process",
368 stream_ssl_set_ca_cert_file__(ca_cert.file_name, true, true);
371 VLOG_ERR("could not bootstrap CA cert: creating %s failed: %s",
372 ca_cert.file_name, ovs_strerror(errno));
377 file = fdopen(fd, "w");
380 VLOG_ERR("could not bootstrap CA cert: fdopen failed: %s",
381 ovs_strerror(error));
382 unlink(ca_cert.file_name);
386 if (!PEM_write_X509(file, cert)) {
387 VLOG_ERR("could not bootstrap CA cert: PEM_write_X509 to %s failed: "
388 "%s", ca_cert.file_name,
389 ERR_error_string(ERR_get_error(), NULL));
391 unlink(ca_cert.file_name);
397 VLOG_ERR("could not bootstrap CA cert: writing %s failed: %s",
398 ca_cert.file_name, ovs_strerror(error));
399 unlink(ca_cert.file_name);
403 VLOG_INFO("successfully bootstrapped CA cert to %s", ca_cert.file_name);
404 log_ca_cert(ca_cert.file_name, cert);
405 bootstrap_ca_cert = false;
408 /* SSL_CTX_add_client_CA makes a copy of cert's relevant data. */
409 SSL_CTX_add_client_CA(ctx, cert);
411 /* SSL_CTX_use_certificate() takes ownership of the certificate passed in.
412 * 'cert' is owned by sslv->ssl, so we need to duplicate it. */
413 cert = X509_dup(cert);
417 SSL_CTX_set_cert_store(ctx, X509_STORE_new());
418 if (SSL_CTX_load_verify_locations(ctx, ca_cert.file_name, NULL) != 1) {
419 VLOG_ERR("SSL_CTX_load_verify_locations: %s",
420 ERR_error_string(ERR_get_error(), NULL));
423 VLOG_INFO("killing successful connection to retry using CA cert");
428 ssl_connect(struct stream *stream)
430 struct ssl_stream *sslv = ssl_stream_cast(stream);
433 switch (sslv->state) {
434 case STATE_TCP_CONNECTING:
435 retval = check_connection_completion(sslv->fd);
439 sslv->state = STATE_SSL_CONNECTING;
440 setsockopt_tcp_nodelay(sslv->fd);
443 case STATE_SSL_CONNECTING:
444 /* Capture the first few bytes of received data so that we can guess
445 * what kind of funny data we've been sent if SSL negotiation fails. */
446 if (sslv->n_head <= 0) {
447 sslv->n_head = recv(sslv->fd, sslv->head, sizeof sslv->head,
451 retval = (sslv->type == CLIENT
452 ? SSL_connect(sslv->ssl) : SSL_accept(sslv->ssl));
454 int error = SSL_get_error(sslv->ssl, retval);
455 if (retval < 0 && ssl_wants_io(error)) {
460 interpret_ssl_error((sslv->type == CLIENT ? "SSL_connect"
461 : "SSL_accept"), retval, error, &unused);
462 shutdown(sslv->fd, SHUT_RDWR);
463 stream_report_content(sslv->head, sslv->n_head, STREAM_SSL,
464 THIS_MODULE, stream_get_name(stream));
467 } else if (bootstrap_ca_cert) {
468 return do_ca_cert_bootstrap(stream);
469 } else if (verify_peer_cert
470 && ((SSL_get_verify_mode(sslv->ssl)
471 & (SSL_VERIFY_NONE | SSL_VERIFY_PEER))
472 != SSL_VERIFY_PEER)) {
473 /* Two or more SSL connections completed at the same time while we
474 * were in bootstrap mode. Only one of these can finish the
475 * bootstrap successfully. The other one(s) must be rejected
476 * because they were not verified against the bootstrapped CA
477 * certificate. (Alternatively we could verify them against the CA
478 * certificate, but that's more trouble than it's worth. These
479 * connections will succeed the next time they retry, assuming that
480 * they have a certificate against the correct CA.) */
481 VLOG_INFO("rejecting SSL connection during bootstrap race window");
492 ssl_close(struct stream *stream)
494 struct ssl_stream *sslv = ssl_stream_cast(stream);
495 ssl_clear_txbuf(sslv);
497 /* Attempt clean shutdown of the SSL connection. This will work most of
498 * the time, as long as the kernel send buffer has some free space and the
499 * SSL connection isn't renegotiating, etc. That has to be good enough,
500 * since we don't have any way to continue the close operation in the
502 SSL_shutdown(sslv->ssl);
504 /* SSL_shutdown() might have signaled an error, in which case we need to
505 * flush it out of the OpenSSL error queue or the next OpenSSL operation
506 * will falsely signal an error. */
510 closesocket(sslv->fd);
515 interpret_queued_ssl_error(const char *function)
517 int queued_error = ERR_get_error();
518 if (queued_error != 0) {
519 VLOG_WARN_RL(&rl, "%s: %s",
520 function, ERR_error_string(queued_error, NULL));
522 VLOG_ERR_RL(&rl, "%s: SSL_ERROR_SSL without queued error", function);
527 interpret_ssl_error(const char *function, int ret, int error,
534 VLOG_ERR_RL(&rl, "%s: unexpected SSL_ERROR_NONE", function);
537 case SSL_ERROR_ZERO_RETURN:
538 VLOG_ERR_RL(&rl, "%s: unexpected SSL_ERROR_ZERO_RETURN", function);
541 case SSL_ERROR_WANT_READ:
545 case SSL_ERROR_WANT_WRITE:
549 case SSL_ERROR_WANT_CONNECT:
550 VLOG_ERR_RL(&rl, "%s: unexpected SSL_ERROR_WANT_CONNECT", function);
553 case SSL_ERROR_WANT_ACCEPT:
554 VLOG_ERR_RL(&rl, "%s: unexpected SSL_ERROR_WANT_ACCEPT", function);
557 case SSL_ERROR_WANT_X509_LOOKUP:
558 VLOG_ERR_RL(&rl, "%s: unexpected SSL_ERROR_WANT_X509_LOOKUP",
562 case SSL_ERROR_SYSCALL: {
563 int queued_error = ERR_get_error();
564 if (queued_error == 0) {
567 VLOG_WARN_RL(&rl, "%s: system error (%s)",
568 function, ovs_strerror(status));
571 VLOG_WARN_RL(&rl, "%s: unexpected SSL connection close",
576 VLOG_WARN_RL(&rl, "%s: %s",
577 function, ERR_error_string(queued_error, NULL));
583 interpret_queued_ssl_error(function);
587 VLOG_ERR_RL(&rl, "%s: bad SSL error code %d", function, error);
594 ssl_recv(struct stream *stream, void *buffer, size_t n)
596 struct ssl_stream *sslv = ssl_stream_cast(stream);
600 /* Behavior of zero-byte SSL_read is poorly defined. */
603 old_state = SSL_get_state(sslv->ssl);
604 ret = SSL_read(sslv->ssl, buffer, n);
605 if (old_state != SSL_get_state(sslv->ssl)) {
606 sslv->tx_want = SSL_NOTHING;
608 sslv->rx_want = SSL_NOTHING;
613 int error = SSL_get_error(sslv->ssl, ret);
614 if (error == SSL_ERROR_ZERO_RETURN) {
617 return -interpret_ssl_error("SSL_read", ret, error,
624 ssl_clear_txbuf(struct ssl_stream *sslv)
626 ofpbuf_delete(sslv->txbuf);
631 ssl_do_tx(struct stream *stream)
633 struct ssl_stream *sslv = ssl_stream_cast(stream);
636 int old_state = SSL_get_state(sslv->ssl);
637 int ret = SSL_write(sslv->ssl, sslv->txbuf->data, sslv->txbuf->size);
638 if (old_state != SSL_get_state(sslv->ssl)) {
639 sslv->rx_want = SSL_NOTHING;
641 sslv->tx_want = SSL_NOTHING;
643 ofpbuf_pull(sslv->txbuf, ret);
644 if (sslv->txbuf->size == 0) {
648 int ssl_error = SSL_get_error(sslv->ssl, ret);
649 if (ssl_error == SSL_ERROR_ZERO_RETURN) {
650 VLOG_WARN_RL(&rl, "SSL_write: connection closed");
653 return interpret_ssl_error("SSL_write", ret, ssl_error,
661 ssl_send(struct stream *stream, const void *buffer, size_t n)
663 struct ssl_stream *sslv = ssl_stream_cast(stream);
670 sslv->txbuf = ofpbuf_clone_data(buffer, n);
671 error = ssl_do_tx(stream);
674 ssl_clear_txbuf(sslv);
686 ssl_run(struct stream *stream)
688 struct ssl_stream *sslv = ssl_stream_cast(stream);
690 if (sslv->txbuf && ssl_do_tx(stream) != EAGAIN) {
691 ssl_clear_txbuf(sslv);
696 ssl_run_wait(struct stream *stream)
698 struct ssl_stream *sslv = ssl_stream_cast(stream);
700 if (sslv->tx_want != SSL_NOTHING) {
701 poll_fd_wait(sslv->fd, want_to_poll_events(sslv->tx_want));
706 ssl_wait(struct stream *stream, enum stream_wait_type wait)
708 struct ssl_stream *sslv = ssl_stream_cast(stream);
712 if (stream_connect(stream) != EAGAIN) {
713 poll_immediate_wake();
715 switch (sslv->state) {
716 case STATE_TCP_CONNECTING:
717 poll_fd_wait(sslv->fd, POLLOUT);
720 case STATE_SSL_CONNECTING:
721 /* ssl_connect() called SSL_accept() or SSL_connect(), which
722 * set up the status that we test here. */
723 poll_fd_wait(sslv->fd,
724 want_to_poll_events(SSL_want(sslv->ssl)));
734 if (sslv->rx_want != SSL_NOTHING) {
735 poll_fd_wait(sslv->fd, want_to_poll_events(sslv->rx_want));
737 poll_immediate_wake();
743 /* We have room in our tx queue. */
744 poll_immediate_wake();
746 /* stream_run_wait() will do the right thing; don't bother with
756 const struct stream_class ssl_stream_class = {
758 true, /* needs_probes */
760 ssl_close, /* close */
761 ssl_connect, /* connect */
765 ssl_run_wait, /* run_wait */
773 struct pstream pstream;
777 const struct pstream_class pssl_pstream_class;
779 static struct pssl_pstream *
780 pssl_pstream_cast(struct pstream *pstream)
782 pstream_assert_class(pstream, &pssl_pstream_class);
783 return CONTAINER_OF(pstream, struct pssl_pstream, pstream);
787 pssl_open(const char *name OVS_UNUSED, char *suffix, struct pstream **pstreamp,
790 char bound_name[SS_NTOP_BUFSIZE + 16];
791 char addrbuf[SS_NTOP_BUFSIZE];
792 struct sockaddr_storage ss;
793 struct pssl_pstream *pssl;
803 fd = inet_open_passive(SOCK_STREAM, suffix, OFP_PORT, &ss, dscp, true);
808 port = ss_get_port(&ss);
809 snprintf(bound_name, sizeof bound_name, "ptcp:%"PRIu16":%s",
810 port, ss_format_address(&ss, addrbuf, sizeof addrbuf));
812 pssl = xmalloc(sizeof *pssl);
813 pstream_init(&pssl->pstream, &pssl_pstream_class, bound_name);
814 pstream_set_bound_port(&pssl->pstream, htons(port));
816 *pstreamp = &pssl->pstream;
821 pssl_close(struct pstream *pstream)
823 struct pssl_pstream *pssl = pssl_pstream_cast(pstream);
824 closesocket(pssl->fd);
829 pssl_accept(struct pstream *pstream, struct stream **new_streamp)
831 struct pssl_pstream *pssl = pssl_pstream_cast(pstream);
832 char name[SS_NTOP_BUFSIZE + 16];
833 char addrbuf[SS_NTOP_BUFSIZE];
834 struct sockaddr_storage ss;
835 socklen_t ss_len = sizeof ss;
839 new_fd = accept(pssl->fd, (struct sockaddr *) &ss, &ss_len);
841 error = sock_errno();
843 if (error == WSAEWOULDBLOCK) {
847 if (error != EAGAIN) {
848 VLOG_DBG_RL(&rl, "accept: %s", sock_strerror(error));
853 error = set_nonblocking(new_fd);
859 snprintf(name, sizeof name, "tcp:%s:%"PRIu16,
860 ss_format_address(&ss, addrbuf, sizeof addrbuf),
862 return new_ssl_stream(name, new_fd, SERVER, STATE_SSL_CONNECTING,
867 pssl_wait(struct pstream *pstream)
869 struct pssl_pstream *pssl = pssl_pstream_cast(pstream);
870 poll_fd_wait(pssl->fd, POLLIN);
873 const struct pstream_class pssl_pstream_class = {
883 * Returns true if OpenSSL error is WANT_READ or WANT_WRITE, indicating that
884 * OpenSSL is requesting that we call it back when the socket is ready for read
885 * or writing, respectively.
888 ssl_wants_io(int ssl_error)
890 return (ssl_error == SSL_ERROR_WANT_WRITE
891 || ssl_error == SSL_ERROR_WANT_READ);
897 static int init_status = -1;
898 if (init_status < 0) {
899 init_status = do_ssl_init();
900 ovs_assert(init_status >= 0);
911 /* The following call is needed if we "#include <openssl/applink.c>". */
912 CRYPTO_malloc_init();
915 SSL_load_error_strings();
917 if (!RAND_status()) {
918 /* We occasionally see OpenSSL fail to seed its random number generator
919 * in heavily loaded hypervisors. I suspect the following scenario:
921 * 1. OpenSSL calls read() to get 32 bytes from /dev/urandom.
922 * 2. The kernel generates 10 bytes of randomness and copies it out.
923 * 3. A signal arrives (perhaps SIGALRM).
924 * 4. The kernel interrupts the system call to service the signal.
925 * 5. Userspace gets 10 bytes of entropy.
926 * 6. OpenSSL doesn't read again to get the final 22 bytes. Therefore
927 * OpenSSL doesn't have enough entropy to consider itself
930 * The only part I'm not entirely sure about is #6, because the OpenSSL
931 * code is so hard to read. */
935 VLOG_WARN("OpenSSL random seeding failed, reseeding ourselves");
937 retval = get_entropy(seed, sizeof seed);
939 VLOG_ERR("failed to obtain entropy (%s)",
940 ovs_retval_to_string(retval));
941 return retval > 0 ? retval : ENOPROTOOPT;
944 RAND_seed(seed, sizeof seed);
947 /* OpenSSL has a bunch of "connection methods": SSLv2_method(),
948 * SSLv3_method(), TLSv1_method(), SSLv23_method(), ... Most of these
949 * support exactly one version of SSL, e.g. TLSv1_method() supports TLSv1
950 * only, not any earlier *or later* version. The only exception is
951 * SSLv23_method(), which in fact supports *any* version of SSL and TLS.
952 * We don't want SSLv2 or SSLv3 support, so we turn it off below with
953 * SSL_CTX_set_options().
955 * The cast is needed to avoid a warning with newer versions of OpenSSL in
956 * which SSLv23_method() returns a "const" pointer. */
957 method = CONST_CAST(SSL_METHOD *, SSLv23_method());
958 if (method == NULL) {
959 VLOG_ERR("TLSv1_method: %s", ERR_error_string(ERR_get_error(), NULL));
963 ctx = SSL_CTX_new(method);
965 VLOG_ERR("SSL_CTX_new: %s", ERR_error_string(ERR_get_error(), NULL));
968 SSL_CTX_set_options(ctx, SSL_OP_NO_SSLv2 | SSL_OP_NO_SSLv3);
969 SSL_CTX_set_tmp_dh_callback(ctx, tmp_dh_callback);
970 SSL_CTX_set_mode(ctx, SSL_MODE_ENABLE_PARTIAL_WRITE);
971 SSL_CTX_set_mode(ctx, SSL_MODE_ACCEPT_MOVING_WRITE_BUFFER);
972 SSL_CTX_set_verify(ctx, SSL_VERIFY_PEER | SSL_VERIFY_FAIL_IF_NO_PEER_CERT,
974 SSL_CTX_set_session_cache_mode(ctx, SSL_SESS_CACHE_OFF);
980 tmp_dh_callback(SSL *ssl OVS_UNUSED, int is_export OVS_UNUSED, int keylength)
985 DH *(*constructor)(void);
988 static struct dh dh_table[] = {
989 {1024, NULL, get_dh1024},
990 {2048, NULL, get_dh2048},
991 {4096, NULL, get_dh4096},
996 for (dh = dh_table; dh < &dh_table[ARRAY_SIZE(dh_table)]; dh++) {
997 if (dh->keylength == keylength) {
999 dh->dh = dh->constructor();
1007 VLOG_ERR_RL(&rl, "no Diffie-Hellman parameters for key length %d",
1012 /* Returns true if SSL is at least partially configured. */
1014 stream_ssl_is_configured(void)
1016 return private_key.file_name || certificate.file_name || ca_cert.file_name;
1020 update_ssl_config(struct ssl_config_file *config, const char *file_name)
1022 struct timespec mtime;
1025 if (ssl_init() || !file_name) {
1029 /* If the file name hasn't changed and neither has the file contents, stop
1031 error = get_mtime(file_name, &mtime);
1032 if (error && error != ENOENT) {
1033 VLOG_ERR_RL(&rl, "%s: stat failed (%s)",
1034 file_name, ovs_strerror(error));
1036 if (config->file_name
1037 && !strcmp(config->file_name, file_name)
1038 && mtime.tv_sec == config->mtime.tv_sec
1039 && mtime.tv_nsec == config->mtime.tv_nsec) {
1043 /* Update 'config'. */
1044 config->mtime = mtime;
1045 if (file_name != config->file_name) {
1046 free(config->file_name);
1047 config->file_name = xstrdup(file_name);
1053 stream_ssl_set_private_key_file__(const char *file_name)
1055 if (SSL_CTX_use_PrivateKey_file(ctx, file_name, SSL_FILETYPE_PEM) == 1) {
1056 private_key.read = true;
1058 VLOG_ERR("SSL_use_PrivateKey_file: %s",
1059 ERR_error_string(ERR_get_error(), NULL));
1064 stream_ssl_set_private_key_file(const char *file_name)
1066 if (update_ssl_config(&private_key, file_name)) {
1067 stream_ssl_set_private_key_file__(file_name);
1072 stream_ssl_set_certificate_file__(const char *file_name)
1074 if (SSL_CTX_use_certificate_file(ctx, file_name, SSL_FILETYPE_PEM) == 1) {
1075 certificate.read = true;
1077 VLOG_ERR("SSL_use_certificate_file: %s",
1078 ERR_error_string(ERR_get_error(), NULL));
1083 stream_ssl_set_certificate_file(const char *file_name)
1085 if (update_ssl_config(&certificate, file_name)) {
1086 stream_ssl_set_certificate_file__(file_name);
1090 /* Sets the private key and certificate files in one operation. Use this
1091 * interface, instead of calling stream_ssl_set_private_key_file() and
1092 * stream_ssl_set_certificate_file() individually, in the main loop of a
1093 * long-running program whose key and certificate might change at runtime.
1095 * This is important because of OpenSSL's behavior. If an OpenSSL context
1096 * already has a certificate, and stream_ssl_set_private_key_file() is called
1097 * to install a new private key, OpenSSL will report an error because the new
1098 * private key does not match the old certificate. The other order, of setting
1099 * a new certificate, then setting a new private key, does work.
1101 * If this were the only problem, calling stream_ssl_set_certificate_file()
1102 * before stream_ssl_set_private_key_file() would fix it. But, if the private
1103 * key is changed before the certificate (e.g. someone "scp"s or "mv"s the new
1104 * private key in place before the certificate), then OpenSSL would reject that
1105 * change, and then the change of certificate would succeed, but there would be
1106 * no associated private key (because it had only changed once and therefore
1107 * there was no point in re-reading it).
1109 * This function avoids both problems by, whenever either the certificate or
1110 * the private key file changes, re-reading both of them, in the correct order.
1113 stream_ssl_set_key_and_cert(const char *private_key_file,
1114 const char *certificate_file)
1116 if (update_ssl_config(&private_key, private_key_file)
1117 || update_ssl_config(&certificate, certificate_file)) {
1118 stream_ssl_set_certificate_file__(certificate_file);
1119 stream_ssl_set_private_key_file__(private_key_file);
1123 /* Reads the X509 certificate or certificates in file 'file_name'. On success,
1124 * stores the address of the first element in an array of pointers to
1125 * certificates in '*certs' and the number of certificates in the array in
1126 * '*n_certs', and returns 0. On failure, stores a null pointer in '*certs', 0
1127 * in '*n_certs', and returns a positive errno value.
1129 * The caller is responsible for freeing '*certs'. */
1131 read_cert_file(const char *file_name, X509 ***certs, size_t *n_certs)
1134 size_t allocated_certs = 0;
1139 file = fopen(file_name, "r");
1141 VLOG_ERR("failed to open %s for reading: %s",
1142 file_name, ovs_strerror(errno));
1150 /* Read certificate from file. */
1151 certificate = PEM_read_X509(file, NULL, NULL, NULL);
1155 VLOG_ERR("PEM_read_X509 failed reading %s: %s",
1156 file_name, ERR_error_string(ERR_get_error(), NULL));
1157 for (i = 0; i < *n_certs; i++) {
1158 X509_free((*certs)[i]);
1167 /* Add certificate to array. */
1168 if (*n_certs >= allocated_certs) {
1169 *certs = x2nrealloc(*certs, &allocated_certs, sizeof **certs);
1171 (*certs)[(*n_certs)++] = certificate;
1173 /* Are there additional certificates in the file? */
1176 } while (isspace(c));
1187 /* Sets 'file_name' as the name of a file containing one or more X509
1188 * certificates to send to the peer. Typical use in OpenFlow is to send the CA
1189 * certificate to the peer, which enables a switch to pick up the controller's
1190 * CA certificate on its first connection. */
1192 stream_ssl_set_peer_ca_cert_file(const char *file_name)
1202 if (!read_cert_file(file_name, &certs, &n_certs)) {
1203 for (i = 0; i < n_certs; i++) {
1204 if (SSL_CTX_add_extra_chain_cert(ctx, certs[i]) != 1) {
1205 VLOG_ERR("SSL_CTX_add_extra_chain_cert: %s",
1206 ERR_error_string(ERR_get_error(), NULL));
1213 /* Logs fingerprint of CA certificate 'cert' obtained from 'file_name'. */
1215 log_ca_cert(const char *file_name, X509 *cert)
1217 unsigned char digest[EVP_MAX_MD_SIZE];
1218 unsigned int n_bytes;
1223 if (!X509_digest(cert, EVP_sha1(), digest, &n_bytes)) {
1224 ds_put_cstr(&fp, "<out of memory>");
1227 for (i = 0; i < n_bytes; i++) {
1229 ds_put_char(&fp, ':');
1231 ds_put_format(&fp, "%02x", digest[i]);
1234 subject = X509_NAME_oneline(X509_get_subject_name(cert), NULL, 0);
1235 VLOG_INFO("Trusting CA cert from %s (%s) (fingerprint %s)", file_name,
1236 subject ? subject : "<out of memory>", ds_cstr(&fp));
1237 OPENSSL_free(subject);
1242 stream_ssl_set_ca_cert_file__(const char *file_name,
1243 bool bootstrap, bool force)
1247 if (!update_ssl_config(&ca_cert, file_name) && !force) {
1251 if (!strcmp(file_name, "none")) {
1252 verify_peer_cert = false;
1253 VLOG_WARN("Peer certificate validation disabled "
1254 "(this is a security risk)");
1255 } else if (bootstrap && stat(file_name, &s) && errno == ENOENT) {
1256 bootstrap_ca_cert = true;
1258 STACK_OF(X509_NAME) *cert_names = SSL_load_client_CA_file(file_name);
1260 /* Set up list of CAs that the server will accept from the
1262 SSL_CTX_set_client_CA_list(ctx, cert_names);
1264 /* Set up CAs for OpenSSL to trust in verifying the peer's
1266 SSL_CTX_set_cert_store(ctx, X509_STORE_new());
1267 if (SSL_CTX_load_verify_locations(ctx, file_name, NULL) != 1) {
1268 VLOG_ERR("SSL_CTX_load_verify_locations: %s",
1269 ERR_error_string(ERR_get_error(), NULL));
1272 bootstrap_ca_cert = false;
1274 VLOG_ERR("failed to load client certificates from %s: %s",
1275 file_name, ERR_error_string(ERR_get_error(), NULL));
1278 ca_cert.read = true;
1281 /* Sets 'file_name' as the name of the file from which to read the CA
1282 * certificate used to verify the peer within SSL connections. If 'bootstrap'
1283 * is false, the file must exist. If 'bootstrap' is false, then the file is
1284 * read if it is exists; if it does not, then it will be created from the CA
1285 * certificate received from the peer on the first SSL connection. */
1287 stream_ssl_set_ca_cert_file(const char *file_name, bool bootstrap)
1289 stream_ssl_set_ca_cert_file__(file_name, bootstrap, false);
1292 /* SSL protocol logging. */
1295 ssl_alert_level_to_string(uint8_t type)
1298 case 1: return "warning";
1299 case 2: return "fatal";
1300 default: return "<unknown>";
1305 ssl_alert_description_to_string(uint8_t type)
1308 case 0: return "close_notify";
1309 case 10: return "unexpected_message";
1310 case 20: return "bad_record_mac";
1311 case 21: return "decryption_failed";
1312 case 22: return "record_overflow";
1313 case 30: return "decompression_failure";
1314 case 40: return "handshake_failure";
1315 case 42: return "bad_certificate";
1316 case 43: return "unsupported_certificate";
1317 case 44: return "certificate_revoked";
1318 case 45: return "certificate_expired";
1319 case 46: return "certificate_unknown";
1320 case 47: return "illegal_parameter";
1321 case 48: return "unknown_ca";
1322 case 49: return "access_denied";
1323 case 50: return "decode_error";
1324 case 51: return "decrypt_error";
1325 case 60: return "export_restriction";
1326 case 70: return "protocol_version";
1327 case 71: return "insufficient_security";
1328 case 80: return "internal_error";
1329 case 90: return "user_canceled";
1330 case 100: return "no_renegotiation";
1331 default: return "<unknown>";
1336 ssl_handshake_type_to_string(uint8_t type)
1339 case 0: return "hello_request";
1340 case 1: return "client_hello";
1341 case 2: return "server_hello";
1342 case 11: return "certificate";
1343 case 12: return "server_key_exchange";
1344 case 13: return "certificate_request";
1345 case 14: return "server_hello_done";
1346 case 15: return "certificate_verify";
1347 case 16: return "client_key_exchange";
1348 case 20: return "finished";
1349 default: return "<unknown>";
1354 ssl_protocol_cb(int write_p, int version OVS_UNUSED, int content_type,
1355 const void *buf_, size_t len, SSL *ssl OVS_UNUSED, void *sslv_)
1357 const struct ssl_stream *sslv = sslv_;
1358 const uint8_t *buf = buf_;
1361 if (!VLOG_IS_DBG_ENABLED()) {
1366 if (content_type == 20) {
1367 ds_put_cstr(&details, "change_cipher_spec");
1368 } else if (content_type == 21) {
1369 ds_put_format(&details, "alert: %s, %s",
1370 ssl_alert_level_to_string(buf[0]),
1371 ssl_alert_description_to_string(buf[1]));
1372 } else if (content_type == 22) {
1373 ds_put_format(&details, "handshake: %s",
1374 ssl_handshake_type_to_string(buf[0]));
1376 ds_put_format(&details, "type %d", content_type);
1379 VLOG_DBG("%s%u%s%s %s (%"PRIuSIZE" bytes)",
1380 sslv->type == CLIENT ? "client" : "server",
1381 sslv->session_nr, write_p ? "-->" : "<--",
1382 stream_get_name(&sslv->stream), ds_cstr(&details), len);
1384 ds_destroy(&details);