2 * Copyright (c) 2008, 2009, 2010, 2011, 2012, 2013, 2014 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"
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;
88 unsigned int session_nr;
90 /* rx_want and tx_want record the result of the last call to SSL_read()
91 * and SSL_write(), respectively:
93 * - If the call reported that data needed to be read from the file
94 * descriptor, the corresponding member is set to SSL_READING.
96 * - If the call reported that data needed to be written to the file
97 * descriptor, the corresponding member is set to SSL_WRITING.
99 * - Otherwise, the member is set to SSL_NOTHING, indicating that the
100 * call completed successfully (or with an error) and that there is no
103 * These are needed because there is no way to ask OpenSSL what a data read
104 * or write would require without giving it a buffer to receive into or
105 * data to send, respectively. (Note that the SSL_want() status is
106 * overwritten by each SSL_read() or SSL_write() call, so we can't rely on
109 * A single call to SSL_read() or SSL_write() can perform both reading
110 * and writing and thus invalidate not one of these values but actually
111 * both. Consider this situation, for example:
113 * - SSL_write() blocks on a read, so tx_want gets SSL_READING.
115 * - SSL_read() laters succeeds reading from 'fd' and clears out the
116 * whole receive buffer, so rx_want gets SSL_READING.
118 * - Client calls stream_wait(STREAM_RECV) and stream_wait(STREAM_SEND)
121 * - Now we're stuck blocking until the peer sends us data, even though
122 * SSL_write() could now succeed, which could easily be a deadlock
125 * On the other hand, we can't reset both tx_want and rx_want on every call
126 * to SSL_read() or SSL_write(), because that would produce livelock,
127 * e.g. in this situation:
129 * - SSL_write() blocks, so tx_want gets SSL_READING or SSL_WRITING.
131 * - SSL_read() blocks, so rx_want gets SSL_READING or SSL_WRITING,
132 * but tx_want gets reset to SSL_NOTHING.
134 * - Client calls stream_wait(STREAM_RECV) and stream_wait(STREAM_SEND)
137 * - Client wakes up immediately since SSL_NOTHING in tx_want indicates
138 * that no blocking is necessary.
140 * The solution we adopt here is to set tx_want to SSL_NOTHING after
141 * calling SSL_read() only if the SSL state of the connection changed,
142 * which indicates that an SSL-level renegotiation made some progress, and
143 * similarly for rx_want and SSL_write(). This prevents both the
144 * deadlock and livelock situations above.
146 int rx_want, tx_want;
148 /* A few bytes of header data in case SSL negotiation fails. */
153 /* SSL context created by ssl_init(). */
156 struct ssl_config_file {
157 bool read; /* Whether the file was successfully read. */
158 char *file_name; /* Configured file name, if any. */
159 struct timespec mtime; /* File mtime as of last time we read it. */
162 /* SSL configuration files. */
163 static struct ssl_config_file private_key;
164 static struct ssl_config_file certificate;
165 static struct ssl_config_file ca_cert;
167 /* Ordinarily, the SSL client and server verify each other's certificates using
168 * a CA certificate. Setting this to false disables this behavior. (This is a
170 static bool verify_peer_cert = true;
172 /* Ordinarily, we require a CA certificate for the peer to be locally
173 * available. We can, however, bootstrap the CA certificate from the peer at
174 * the beginning of our first connection then use that certificate on all
175 * subsequent connections, saving it to a file for use in future runs also. In
176 * this case, 'bootstrap_ca_cert' is true. */
177 static bool bootstrap_ca_cert;
179 /* Session number. Used in debug logging messages to uniquely identify a
181 static unsigned int next_session_nr;
183 /* Who knows what can trigger various SSL errors, so let's throttle them down
185 static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(10, 25);
187 static int ssl_init(void);
188 static int do_ssl_init(void);
189 static bool ssl_wants_io(int ssl_error);
190 static void ssl_close(struct stream *);
191 static void ssl_clear_txbuf(struct ssl_stream *);
192 static void interpret_queued_ssl_error(const char *function);
193 static int interpret_ssl_error(const char *function, int ret, int error,
195 static DH *tmp_dh_callback(SSL *ssl, int is_export OVS_UNUSED, int keylength);
196 static void log_ca_cert(const char *file_name, X509 *cert);
197 static void stream_ssl_set_ca_cert_file__(const char *file_name,
198 bool bootstrap, bool force);
199 static void ssl_protocol_cb(int write_p, int version, int content_type,
200 const void *, size_t, SSL *, void *sslv_);
201 static bool update_ssl_config(struct ssl_config_file *, const char *file_name);
202 static int sock_errno(void);
203 static void clear_handle(int fd, HANDLE wevent);
206 want_to_poll_events(int want)
224 setsockopt_tcp_nodelay(int fd)
229 retval = setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &on, sizeof on);
231 retval = sock_errno();
232 VLOG_ERR("setsockopt(TCP_NODELAY): %s", sock_strerror(retval));
238 new_ssl_stream(const char *name, int fd, enum session_type type,
239 enum ssl_state state, struct stream **streamp)
241 struct sockaddr_storage local;
242 socklen_t local_len = sizeof local;
243 struct ssl_stream *sslv;
247 /* Check for all the needful configuration. */
249 if (!private_key.read) {
250 VLOG_ERR("Private key must be configured to use SSL");
251 retval = ENOPROTOOPT;
253 if (!certificate.read) {
254 VLOG_ERR("Certificate must be configured to use SSL");
255 retval = ENOPROTOOPT;
257 if (!ca_cert.read && verify_peer_cert && !bootstrap_ca_cert) {
258 VLOG_ERR("CA certificate must be configured to use SSL");
259 retval = ENOPROTOOPT;
261 if (!retval && !SSL_CTX_check_private_key(ctx)) {
262 VLOG_ERR("Private key does not match certificate public key: %s",
263 ERR_error_string(ERR_get_error(), NULL));
264 retval = ENOPROTOOPT;
270 /* Get the local IP and port information */
271 retval = getsockname(fd, (struct sockaddr *) &local, &local_len);
273 memset(&local, 0, sizeof local);
277 * On windows platforms, this can only be called upon TCP connected.
279 if (state == STATE_SSL_CONNECTING) {
280 retval = setsockopt_tcp_nodelay(fd);
286 /* Create and configure OpenSSL stream. */
289 VLOG_ERR("SSL_new: %s", ERR_error_string(ERR_get_error(), NULL));
290 retval = ENOPROTOOPT;
293 if (SSL_set_fd(ssl, fd) == 0) {
294 VLOG_ERR("SSL_set_fd: %s", ERR_error_string(ERR_get_error(), NULL));
295 retval = ENOPROTOOPT;
298 if (!verify_peer_cert || (bootstrap_ca_cert && type == CLIENT)) {
299 SSL_set_verify(ssl, SSL_VERIFY_NONE, NULL);
302 /* Create and return the ssl_stream. */
303 sslv = xmalloc(sizeof *sslv);
304 stream_init(&sslv->stream, &ssl_stream_class, EAGAIN, name);
309 sslv->wevent = CreateEvent(NULL, FALSE, FALSE, NULL);
315 sslv->rx_want = sslv->tx_want = SSL_NOTHING;
316 sslv->session_nr = next_session_nr++;
319 if (VLOG_IS_DBG_ENABLED()) {
320 SSL_set_msg_callback(ssl, ssl_protocol_cb);
321 SSL_set_msg_callback_arg(ssl, sslv);
324 *streamp = &sslv->stream;
335 static struct ssl_stream *
336 ssl_stream_cast(struct stream *stream)
338 stream_assert_class(stream, &ssl_stream_class);
339 return CONTAINER_OF(stream, struct ssl_stream, stream);
343 ssl_open(const char *name, char *suffix, struct stream **streamp, uint8_t dscp)
352 error = inet_open_active(SOCK_STREAM, suffix, OFP_OLD_PORT, NULL, &fd,
355 int state = error ? STATE_TCP_CONNECTING : STATE_SSL_CONNECTING;
356 return new_ssl_stream(name, fd, CLIENT, state, streamp);
358 VLOG_ERR("%s: connect: %s", name, ovs_strerror(error));
364 do_ca_cert_bootstrap(struct stream *stream)
366 struct ssl_stream *sslv = ssl_stream_cast(stream);
367 STACK_OF(X509) *chain;
373 chain = SSL_get_peer_cert_chain(sslv->ssl);
374 if (!chain || !sk_X509_num(chain)) {
375 VLOG_ERR("could not bootstrap CA cert: no certificate presented by "
379 cert = sk_X509_value(chain, sk_X509_num(chain) - 1);
381 /* Check that 'cert' is self-signed. Otherwise it is not a CA
382 * certificate and we should not attempt to use it as one. */
383 error = X509_check_issued(cert, cert);
385 VLOG_ERR("could not bootstrap CA cert: obtained certificate is "
386 "not self-signed (%s)",
387 X509_verify_cert_error_string(error));
388 if (sk_X509_num(chain) < 2) {
389 VLOG_ERR("only one certificate was received, so probably the peer "
390 "is not configured to send its CA certificate");
395 fd = open(ca_cert.file_name, O_CREAT | O_EXCL | O_WRONLY, 0444);
397 if (errno == EEXIST) {
398 VLOG_INFO_RL(&rl, "reading CA cert %s created by another process",
400 stream_ssl_set_ca_cert_file__(ca_cert.file_name, true, true);
403 VLOG_ERR("could not bootstrap CA cert: creating %s failed: %s",
404 ca_cert.file_name, ovs_strerror(errno));
409 file = fdopen(fd, "w");
412 VLOG_ERR("could not bootstrap CA cert: fdopen failed: %s",
413 ovs_strerror(error));
414 unlink(ca_cert.file_name);
418 if (!PEM_write_X509(file, cert)) {
419 VLOG_ERR("could not bootstrap CA cert: PEM_write_X509 to %s failed: "
420 "%s", ca_cert.file_name,
421 ERR_error_string(ERR_get_error(), NULL));
423 unlink(ca_cert.file_name);
429 VLOG_ERR("could not bootstrap CA cert: writing %s failed: %s",
430 ca_cert.file_name, ovs_strerror(error));
431 unlink(ca_cert.file_name);
435 VLOG_INFO("successfully bootstrapped CA cert to %s", ca_cert.file_name);
436 log_ca_cert(ca_cert.file_name, cert);
437 bootstrap_ca_cert = false;
440 /* SSL_CTX_add_client_CA makes a copy of cert's relevant data. */
441 SSL_CTX_add_client_CA(ctx, cert);
443 /* SSL_CTX_use_certificate() takes ownership of the certificate passed in.
444 * 'cert' is owned by sslv->ssl, so we need to duplicate it. */
445 cert = X509_dup(cert);
449 SSL_CTX_set_cert_store(ctx, X509_STORE_new());
450 if (SSL_CTX_load_verify_locations(ctx, ca_cert.file_name, NULL) != 1) {
451 VLOG_ERR("SSL_CTX_load_verify_locations: %s",
452 ERR_error_string(ERR_get_error(), NULL));
455 VLOG_INFO("killing successful connection to retry using CA cert");
460 ssl_connect(struct stream *stream)
462 struct ssl_stream *sslv = ssl_stream_cast(stream);
465 switch (sslv->state) {
466 case STATE_TCP_CONNECTING:
467 retval = check_connection_completion(sslv->fd);
471 sslv->state = STATE_SSL_CONNECTING;
472 retval = setsockopt_tcp_nodelay(sslv->fd);
478 case STATE_SSL_CONNECTING:
479 /* Capture the first few bytes of received data so that we can guess
480 * what kind of funny data we've been sent if SSL negotiation fails. */
481 if (sslv->n_head <= 0) {
482 sslv->n_head = recv(sslv->fd, sslv->head, sizeof sslv->head,
486 retval = (sslv->type == CLIENT
487 ? SSL_connect(sslv->ssl) : SSL_accept(sslv->ssl));
489 int error = SSL_get_error(sslv->ssl, retval);
490 if (retval < 0 && ssl_wants_io(error)) {
495 interpret_ssl_error((sslv->type == CLIENT ? "SSL_connect"
496 : "SSL_accept"), retval, error, &unused);
497 shutdown(sslv->fd, SHUT_RDWR);
498 stream_report_content(sslv->head, sslv->n_head, STREAM_SSL,
499 THIS_MODULE, stream_get_name(stream));
502 } else if (bootstrap_ca_cert) {
503 return do_ca_cert_bootstrap(stream);
504 } else if (verify_peer_cert
505 && ((SSL_get_verify_mode(sslv->ssl)
506 & (SSL_VERIFY_NONE | SSL_VERIFY_PEER))
507 != SSL_VERIFY_PEER)) {
508 /* Two or more SSL connections completed at the same time while we
509 * were in bootstrap mode. Only one of these can finish the
510 * bootstrap successfully. The other one(s) must be rejected
511 * because they were not verified against the bootstrapped CA
512 * certificate. (Alternatively we could verify them against the CA
513 * certificate, but that's more trouble than it's worth. These
514 * connections will succeed the next time they retry, assuming that
515 * they have a certificate against the correct CA.) */
516 VLOG_INFO("rejecting SSL connection during bootstrap race window");
527 ssl_close(struct stream *stream)
529 struct ssl_stream *sslv = ssl_stream_cast(stream);
530 ssl_clear_txbuf(sslv);
532 /* Attempt clean shutdown of the SSL connection. This will work most of
533 * the time, as long as the kernel send buffer has some free space and the
534 * SSL connection isn't renegotiating, etc. That has to be good enough,
535 * since we don't have any way to continue the close operation in the
537 SSL_shutdown(sslv->ssl);
539 /* SSL_shutdown() might have signaled an error, in which case we need to
540 * flush it out of the OpenSSL error queue or the next OpenSSL operation
541 * will falsely signal an error. */
545 clear_handle(sslv->fd, sslv->wevent);
546 closesocket(sslv->fd);
551 interpret_queued_ssl_error(const char *function)
553 int queued_error = ERR_get_error();
554 if (queued_error != 0) {
555 VLOG_WARN_RL(&rl, "%s: %s",
556 function, ERR_error_string(queued_error, NULL));
558 VLOG_ERR_RL(&rl, "%s: SSL_ERROR_SSL without queued error", function);
563 interpret_ssl_error(const char *function, int ret, int error,
570 VLOG_ERR_RL(&rl, "%s: unexpected SSL_ERROR_NONE", function);
573 case SSL_ERROR_ZERO_RETURN:
574 VLOG_ERR_RL(&rl, "%s: unexpected SSL_ERROR_ZERO_RETURN", function);
577 case SSL_ERROR_WANT_READ:
581 case SSL_ERROR_WANT_WRITE:
585 case SSL_ERROR_WANT_CONNECT:
586 VLOG_ERR_RL(&rl, "%s: unexpected SSL_ERROR_WANT_CONNECT", function);
589 case SSL_ERROR_WANT_ACCEPT:
590 VLOG_ERR_RL(&rl, "%s: unexpected SSL_ERROR_WANT_ACCEPT", function);
593 case SSL_ERROR_WANT_X509_LOOKUP:
594 VLOG_ERR_RL(&rl, "%s: unexpected SSL_ERROR_WANT_X509_LOOKUP",
598 case SSL_ERROR_SYSCALL: {
599 int queued_error = ERR_get_error();
600 if (queued_error == 0) {
603 VLOG_WARN_RL(&rl, "%s: system error (%s)",
604 function, ovs_strerror(status));
607 VLOG_WARN_RL(&rl, "%s: unexpected SSL connection close",
612 VLOG_WARN_RL(&rl, "%s: %s",
613 function, ERR_error_string(queued_error, NULL));
619 interpret_queued_ssl_error(function);
623 VLOG_ERR_RL(&rl, "%s: bad SSL error code %d", function, error);
630 ssl_recv(struct stream *stream, void *buffer, size_t n)
632 struct ssl_stream *sslv = ssl_stream_cast(stream);
636 /* Behavior of zero-byte SSL_read is poorly defined. */
639 old_state = SSL_get_state(sslv->ssl);
640 ret = SSL_read(sslv->ssl, buffer, n);
641 if (old_state != SSL_get_state(sslv->ssl)) {
642 sslv->tx_want = SSL_NOTHING;
644 sslv->rx_want = SSL_NOTHING;
649 int error = SSL_get_error(sslv->ssl, ret);
650 if (error == SSL_ERROR_ZERO_RETURN) {
653 return -interpret_ssl_error("SSL_read", ret, error,
660 ssl_clear_txbuf(struct ssl_stream *sslv)
662 ofpbuf_delete(sslv->txbuf);
667 ssl_do_tx(struct stream *stream)
669 struct ssl_stream *sslv = ssl_stream_cast(stream);
672 int old_state = SSL_get_state(sslv->ssl);
673 int ret = SSL_write(sslv->ssl,
674 ofpbuf_data(sslv->txbuf), ofpbuf_size(sslv->txbuf));
675 if (old_state != SSL_get_state(sslv->ssl)) {
676 sslv->rx_want = SSL_NOTHING;
678 sslv->tx_want = SSL_NOTHING;
680 ofpbuf_pull(sslv->txbuf, ret);
681 if (ofpbuf_size(sslv->txbuf) == 0) {
685 int ssl_error = SSL_get_error(sslv->ssl, ret);
686 if (ssl_error == SSL_ERROR_ZERO_RETURN) {
687 VLOG_WARN_RL(&rl, "SSL_write: connection closed");
690 return interpret_ssl_error("SSL_write", ret, ssl_error,
698 ssl_send(struct stream *stream, const void *buffer, size_t n)
700 struct ssl_stream *sslv = ssl_stream_cast(stream);
707 sslv->txbuf = ofpbuf_clone_data(buffer, n);
708 error = ssl_do_tx(stream);
711 ssl_clear_txbuf(sslv);
723 ssl_run(struct stream *stream)
725 struct ssl_stream *sslv = ssl_stream_cast(stream);
727 if (sslv->txbuf && ssl_do_tx(stream) != EAGAIN) {
728 ssl_clear_txbuf(sslv);
733 ssl_run_wait(struct stream *stream)
735 struct ssl_stream *sslv = ssl_stream_cast(stream);
737 if (sslv->tx_want != SSL_NOTHING) {
738 poll_fd_wait_event(sslv->fd, sslv->wevent,
739 want_to_poll_events(sslv->tx_want));
744 ssl_wait(struct stream *stream, enum stream_wait_type wait)
746 struct ssl_stream *sslv = ssl_stream_cast(stream);
750 if (stream_connect(stream) != EAGAIN) {
751 poll_immediate_wake();
753 switch (sslv->state) {
754 case STATE_TCP_CONNECTING:
755 poll_fd_wait_event(sslv->fd, sslv->wevent, POLLOUT);
758 case STATE_SSL_CONNECTING:
759 /* ssl_connect() called SSL_accept() or SSL_connect(), which
760 * set up the status that we test here. */
761 poll_fd_wait_event(sslv->fd, sslv->wevent,
762 want_to_poll_events(SSL_want(sslv->ssl)));
772 if (sslv->rx_want != SSL_NOTHING) {
773 poll_fd_wait_event(sslv->fd, sslv->wevent,
774 want_to_poll_events(sslv->rx_want));
776 poll_immediate_wake();
782 /* We have room in our tx queue. */
783 poll_immediate_wake();
785 /* stream_run_wait() will do the right thing; don't bother with
795 const struct stream_class ssl_stream_class = {
797 true, /* needs_probes */
799 ssl_close, /* close */
800 ssl_connect, /* connect */
804 ssl_run_wait, /* run_wait */
812 struct pstream pstream;
817 const struct pstream_class pssl_pstream_class;
819 static struct pssl_pstream *
820 pssl_pstream_cast(struct pstream *pstream)
822 pstream_assert_class(pstream, &pssl_pstream_class);
823 return CONTAINER_OF(pstream, struct pssl_pstream, pstream);
827 pssl_open(const char *name OVS_UNUSED, char *suffix, struct pstream **pstreamp,
830 char bound_name[SS_NTOP_BUFSIZE + 16];
831 char addrbuf[SS_NTOP_BUFSIZE];
832 struct sockaddr_storage ss;
833 struct pssl_pstream *pssl;
843 fd = inet_open_passive(SOCK_STREAM, suffix, OFP_OLD_PORT, &ss, dscp, true);
848 port = ss_get_port(&ss);
849 snprintf(bound_name, sizeof bound_name, "ptcp:%"PRIu16":%s",
850 port, ss_format_address(&ss, addrbuf, sizeof addrbuf));
852 pssl = xmalloc(sizeof *pssl);
853 pstream_init(&pssl->pstream, &pssl_pstream_class, bound_name);
854 pstream_set_bound_port(&pssl->pstream, htons(port));
857 pssl->wevent = CreateEvent(NULL, FALSE, FALSE, NULL);
861 *pstreamp = &pssl->pstream;
866 pssl_close(struct pstream *pstream)
868 struct pssl_pstream *pssl = pssl_pstream_cast(pstream);
869 clear_handle(pssl->fd, pssl->wevent);
870 closesocket(pssl->fd);
875 pssl_accept(struct pstream *pstream, struct stream **new_streamp)
877 struct pssl_pstream *pssl = pssl_pstream_cast(pstream);
878 char name[SS_NTOP_BUFSIZE + 16];
879 char addrbuf[SS_NTOP_BUFSIZE];
880 struct sockaddr_storage ss;
881 socklen_t ss_len = sizeof ss;
885 new_fd = accept(pssl->fd, (struct sockaddr *) &ss, &ss_len);
887 error = sock_errno();
889 if (error == WSAEWOULDBLOCK) {
893 if (error != EAGAIN) {
894 VLOG_DBG_RL(&rl, "accept: %s", sock_strerror(error));
899 error = set_nonblocking(new_fd);
905 snprintf(name, sizeof name, "tcp:%s:%"PRIu16,
906 ss_format_address(&ss, addrbuf, sizeof addrbuf),
908 return new_ssl_stream(name, new_fd, SERVER, STATE_SSL_CONNECTING,
913 pssl_wait(struct pstream *pstream)
915 struct pssl_pstream *pssl = pssl_pstream_cast(pstream);
916 poll_fd_wait_event(pssl->fd, pssl->wevent, POLLIN);
920 pssl_set_dscp(struct pstream *pstream, uint8_t dscp)
922 struct pssl_pstream *pssl = pssl_pstream_cast(pstream);
923 return set_dscp(pssl->fd, dscp);
926 const struct pstream_class pssl_pstream_class = {
937 * Returns true if OpenSSL error is WANT_READ or WANT_WRITE, indicating that
938 * OpenSSL is requesting that we call it back when the socket is ready for read
939 * or writing, respectively.
942 ssl_wants_io(int ssl_error)
944 return (ssl_error == SSL_ERROR_WANT_WRITE
945 || ssl_error == SSL_ERROR_WANT_READ);
951 static int init_status = -1;
952 if (init_status < 0) {
953 init_status = do_ssl_init();
954 ovs_assert(init_status >= 0);
965 /* The following call is needed if we "#include <openssl/applink.c>". */
966 CRYPTO_malloc_init();
969 SSL_load_error_strings();
971 if (!RAND_status()) {
972 /* We occasionally see OpenSSL fail to seed its random number generator
973 * in heavily loaded hypervisors. I suspect the following scenario:
975 * 1. OpenSSL calls read() to get 32 bytes from /dev/urandom.
976 * 2. The kernel generates 10 bytes of randomness and copies it out.
977 * 3. A signal arrives (perhaps SIGALRM).
978 * 4. The kernel interrupts the system call to service the signal.
979 * 5. Userspace gets 10 bytes of entropy.
980 * 6. OpenSSL doesn't read again to get the final 22 bytes. Therefore
981 * OpenSSL doesn't have enough entropy to consider itself
984 * The only part I'm not entirely sure about is #6, because the OpenSSL
985 * code is so hard to read. */
989 VLOG_WARN("OpenSSL random seeding failed, reseeding ourselves");
991 retval = get_entropy(seed, sizeof seed);
993 VLOG_ERR("failed to obtain entropy (%s)",
994 ovs_retval_to_string(retval));
995 return retval > 0 ? retval : ENOPROTOOPT;
998 RAND_seed(seed, sizeof seed);
1001 /* OpenSSL has a bunch of "connection methods": SSLv2_method(),
1002 * SSLv3_method(), TLSv1_method(), SSLv23_method(), ... Most of these
1003 * support exactly one version of SSL, e.g. TLSv1_method() supports TLSv1
1004 * only, not any earlier *or later* version. The only exception is
1005 * SSLv23_method(), which in fact supports *any* version of SSL and TLS.
1006 * We don't want SSLv2 or SSLv3 support, so we turn it off below with
1007 * SSL_CTX_set_options().
1009 * The cast is needed to avoid a warning with newer versions of OpenSSL in
1010 * which SSLv23_method() returns a "const" pointer. */
1011 method = CONST_CAST(SSL_METHOD *, SSLv23_method());
1012 if (method == NULL) {
1013 VLOG_ERR("TLSv1_method: %s", ERR_error_string(ERR_get_error(), NULL));
1017 ctx = SSL_CTX_new(method);
1019 VLOG_ERR("SSL_CTX_new: %s", ERR_error_string(ERR_get_error(), NULL));
1022 SSL_CTX_set_options(ctx, SSL_OP_NO_SSLv2 | SSL_OP_NO_SSLv3);
1023 SSL_CTX_set_tmp_dh_callback(ctx, tmp_dh_callback);
1024 SSL_CTX_set_mode(ctx, SSL_MODE_ENABLE_PARTIAL_WRITE);
1025 SSL_CTX_set_mode(ctx, SSL_MODE_ACCEPT_MOVING_WRITE_BUFFER);
1026 SSL_CTX_set_verify(ctx, SSL_VERIFY_PEER | SSL_VERIFY_FAIL_IF_NO_PEER_CERT,
1033 tmp_dh_callback(SSL *ssl OVS_UNUSED, int is_export OVS_UNUSED, int keylength)
1038 DH *(*constructor)(void);
1041 static struct dh dh_table[] = {
1042 {1024, NULL, get_dh1024},
1043 {2048, NULL, get_dh2048},
1044 {4096, NULL, get_dh4096},
1049 for (dh = dh_table; dh < &dh_table[ARRAY_SIZE(dh_table)]; dh++) {
1050 if (dh->keylength == keylength) {
1052 dh->dh = dh->constructor();
1060 VLOG_ERR_RL(&rl, "no Diffie-Hellman parameters for key length %d",
1065 /* Returns true if SSL is at least partially configured. */
1067 stream_ssl_is_configured(void)
1069 return private_key.file_name || certificate.file_name || ca_cert.file_name;
1073 update_ssl_config(struct ssl_config_file *config, const char *file_name)
1075 struct timespec mtime;
1078 if (ssl_init() || !file_name) {
1082 /* If the file name hasn't changed and neither has the file contents, stop
1084 error = get_mtime(file_name, &mtime);
1085 if (error && error != ENOENT) {
1086 VLOG_ERR_RL(&rl, "%s: stat failed (%s)",
1087 file_name, ovs_strerror(error));
1089 if (config->file_name
1090 && !strcmp(config->file_name, file_name)
1091 && mtime.tv_sec == config->mtime.tv_sec
1092 && mtime.tv_nsec == config->mtime.tv_nsec) {
1096 /* Update 'config'. */
1097 config->mtime = mtime;
1098 if (file_name != config->file_name) {
1099 free(config->file_name);
1100 config->file_name = xstrdup(file_name);
1106 stream_ssl_set_private_key_file__(const char *file_name)
1108 if (SSL_CTX_use_PrivateKey_file(ctx, file_name, SSL_FILETYPE_PEM) == 1) {
1109 private_key.read = true;
1111 VLOG_ERR("SSL_use_PrivateKey_file: %s",
1112 ERR_error_string(ERR_get_error(), NULL));
1117 stream_ssl_set_private_key_file(const char *file_name)
1119 if (update_ssl_config(&private_key, file_name)) {
1120 stream_ssl_set_private_key_file__(file_name);
1125 stream_ssl_set_certificate_file__(const char *file_name)
1127 if (SSL_CTX_use_certificate_chain_file(ctx, file_name) == 1) {
1128 certificate.read = true;
1130 VLOG_ERR("SSL_use_certificate_file: %s",
1131 ERR_error_string(ERR_get_error(), NULL));
1136 stream_ssl_set_certificate_file(const char *file_name)
1138 if (update_ssl_config(&certificate, file_name)) {
1139 stream_ssl_set_certificate_file__(file_name);
1143 /* Sets the private key and certificate files in one operation. Use this
1144 * interface, instead of calling stream_ssl_set_private_key_file() and
1145 * stream_ssl_set_certificate_file() individually, in the main loop of a
1146 * long-running program whose key and certificate might change at runtime.
1148 * This is important because of OpenSSL's behavior. If an OpenSSL context
1149 * already has a certificate, and stream_ssl_set_private_key_file() is called
1150 * to install a new private key, OpenSSL will report an error because the new
1151 * private key does not match the old certificate. The other order, of setting
1152 * a new certificate, then setting a new private key, does work.
1154 * If this were the only problem, calling stream_ssl_set_certificate_file()
1155 * before stream_ssl_set_private_key_file() would fix it. But, if the private
1156 * key is changed before the certificate (e.g. someone "scp"s or "mv"s the new
1157 * private key in place before the certificate), then OpenSSL would reject that
1158 * change, and then the change of certificate would succeed, but there would be
1159 * no associated private key (because it had only changed once and therefore
1160 * there was no point in re-reading it).
1162 * This function avoids both problems by, whenever either the certificate or
1163 * the private key file changes, re-reading both of them, in the correct order.
1166 stream_ssl_set_key_and_cert(const char *private_key_file,
1167 const char *certificate_file)
1169 if (update_ssl_config(&private_key, private_key_file)
1170 || update_ssl_config(&certificate, certificate_file)) {
1171 stream_ssl_set_certificate_file__(certificate_file);
1172 stream_ssl_set_private_key_file__(private_key_file);
1176 /* Reads the X509 certificate or certificates in file 'file_name'. On success,
1177 * stores the address of the first element in an array of pointers to
1178 * certificates in '*certs' and the number of certificates in the array in
1179 * '*n_certs', and returns 0. On failure, stores a null pointer in '*certs', 0
1180 * in '*n_certs', and returns a positive errno value.
1182 * The caller is responsible for freeing '*certs'. */
1184 read_cert_file(const char *file_name, X509 ***certs, size_t *n_certs)
1187 size_t allocated_certs = 0;
1192 file = fopen(file_name, "r");
1194 VLOG_ERR("failed to open %s for reading: %s",
1195 file_name, ovs_strerror(errno));
1203 /* Read certificate from file. */
1204 certificate = PEM_read_X509(file, NULL, NULL, NULL);
1208 VLOG_ERR("PEM_read_X509 failed reading %s: %s",
1209 file_name, ERR_error_string(ERR_get_error(), NULL));
1210 for (i = 0; i < *n_certs; i++) {
1211 X509_free((*certs)[i]);
1219 /* Add certificate to array. */
1220 if (*n_certs >= allocated_certs) {
1221 *certs = x2nrealloc(*certs, &allocated_certs, sizeof **certs);
1223 (*certs)[(*n_certs)++] = certificate;
1225 /* Are there additional certificates in the file? */
1228 } while (isspace(c));
1239 /* Sets 'file_name' as the name of a file containing one or more X509
1240 * certificates to send to the peer. Typical use in OpenFlow is to send the CA
1241 * certificate to the peer, which enables a switch to pick up the controller's
1242 * CA certificate on its first connection. */
1244 stream_ssl_set_peer_ca_cert_file(const char *file_name)
1254 if (!read_cert_file(file_name, &certs, &n_certs)) {
1255 for (i = 0; i < n_certs; i++) {
1256 if (SSL_CTX_add_extra_chain_cert(ctx, certs[i]) != 1) {
1257 VLOG_ERR("SSL_CTX_add_extra_chain_cert: %s",
1258 ERR_error_string(ERR_get_error(), NULL));
1265 /* Logs fingerprint of CA certificate 'cert' obtained from 'file_name'. */
1267 log_ca_cert(const char *file_name, X509 *cert)
1269 unsigned char digest[EVP_MAX_MD_SIZE];
1270 unsigned int n_bytes;
1275 if (!X509_digest(cert, EVP_sha1(), digest, &n_bytes)) {
1276 ds_put_cstr(&fp, "<out of memory>");
1279 for (i = 0; i < n_bytes; i++) {
1281 ds_put_char(&fp, ':');
1283 ds_put_format(&fp, "%02x", digest[i]);
1286 subject = X509_NAME_oneline(X509_get_subject_name(cert), NULL, 0);
1287 VLOG_INFO("Trusting CA cert from %s (%s) (fingerprint %s)", file_name,
1288 subject ? subject : "<out of memory>", ds_cstr(&fp));
1289 OPENSSL_free(subject);
1294 stream_ssl_set_ca_cert_file__(const char *file_name,
1295 bool bootstrap, bool force)
1301 if (!update_ssl_config(&ca_cert, file_name) && !force) {
1305 if (!strcmp(file_name, "none")) {
1306 verify_peer_cert = false;
1307 VLOG_WARN("Peer certificate validation disabled "
1308 "(this is a security risk)");
1309 } else if (bootstrap && stat(file_name, &s) && errno == ENOENT) {
1310 bootstrap_ca_cert = true;
1311 } else if (!read_cert_file(file_name, &certs, &n_certs)) {
1314 /* Set up list of CAs that the server will accept from the client. */
1315 for (i = 0; i < n_certs; i++) {
1316 /* SSL_CTX_add_client_CA makes a copy of the relevant data. */
1317 if (SSL_CTX_add_client_CA(ctx, certs[i]) != 1) {
1318 VLOG_ERR("failed to add client certificate %"PRIuSIZE" from %s: %s",
1320 ERR_error_string(ERR_get_error(), NULL));
1322 log_ca_cert(file_name, certs[i]);
1324 X509_free(certs[i]);
1328 /* Set up CAs for OpenSSL to trust in verifying the peer's
1330 SSL_CTX_set_cert_store(ctx, X509_STORE_new());
1331 if (SSL_CTX_load_verify_locations(ctx, file_name, NULL) != 1) {
1332 VLOG_ERR("SSL_CTX_load_verify_locations: %s",
1333 ERR_error_string(ERR_get_error(), NULL));
1337 bootstrap_ca_cert = false;
1339 ca_cert.read = true;
1342 /* Sets 'file_name' as the name of the file from which to read the CA
1343 * certificate used to verify the peer within SSL connections. If 'bootstrap'
1344 * is false, the file must exist. If 'bootstrap' is false, then the file is
1345 * read if it is exists; if it does not, then it will be created from the CA
1346 * certificate received from the peer on the first SSL connection. */
1348 stream_ssl_set_ca_cert_file(const char *file_name, bool bootstrap)
1350 stream_ssl_set_ca_cert_file__(file_name, bootstrap, false);
1353 /* SSL protocol logging. */
1356 ssl_alert_level_to_string(uint8_t type)
1359 case 1: return "warning";
1360 case 2: return "fatal";
1361 default: return "<unknown>";
1366 ssl_alert_description_to_string(uint8_t type)
1369 case 0: return "close_notify";
1370 case 10: return "unexpected_message";
1371 case 20: return "bad_record_mac";
1372 case 21: return "decryption_failed";
1373 case 22: return "record_overflow";
1374 case 30: return "decompression_failure";
1375 case 40: return "handshake_failure";
1376 case 42: return "bad_certificate";
1377 case 43: return "unsupported_certificate";
1378 case 44: return "certificate_revoked";
1379 case 45: return "certificate_expired";
1380 case 46: return "certificate_unknown";
1381 case 47: return "illegal_parameter";
1382 case 48: return "unknown_ca";
1383 case 49: return "access_denied";
1384 case 50: return "decode_error";
1385 case 51: return "decrypt_error";
1386 case 60: return "export_restriction";
1387 case 70: return "protocol_version";
1388 case 71: return "insufficient_security";
1389 case 80: return "internal_error";
1390 case 90: return "user_canceled";
1391 case 100: return "no_renegotiation";
1392 default: return "<unknown>";
1397 ssl_handshake_type_to_string(uint8_t type)
1400 case 0: return "hello_request";
1401 case 1: return "client_hello";
1402 case 2: return "server_hello";
1403 case 11: return "certificate";
1404 case 12: return "server_key_exchange";
1405 case 13: return "certificate_request";
1406 case 14: return "server_hello_done";
1407 case 15: return "certificate_verify";
1408 case 16: return "client_key_exchange";
1409 case 20: return "finished";
1410 default: return "<unknown>";
1415 ssl_protocol_cb(int write_p, int version OVS_UNUSED, int content_type,
1416 const void *buf_, size_t len, SSL *ssl OVS_UNUSED, void *sslv_)
1418 const struct ssl_stream *sslv = sslv_;
1419 const uint8_t *buf = buf_;
1422 if (!VLOG_IS_DBG_ENABLED()) {
1427 if (content_type == 20) {
1428 ds_put_cstr(&details, "change_cipher_spec");
1429 } else if (content_type == 21) {
1430 ds_put_format(&details, "alert: %s, %s",
1431 ssl_alert_level_to_string(buf[0]),
1432 ssl_alert_description_to_string(buf[1]));
1433 } else if (content_type == 22) {
1434 ds_put_format(&details, "handshake: %s",
1435 ssl_handshake_type_to_string(buf[0]));
1437 ds_put_format(&details, "type %d", content_type);
1440 VLOG_DBG("%s%u%s%s %s (%"PRIuSIZE" bytes)",
1441 sslv->type == CLIENT ? "client" : "server",
1442 sslv->session_nr, write_p ? "-->" : "<--",
1443 stream_get_name(&sslv->stream), ds_cstr(&details), len);
1445 ds_destroy(&details);
1449 clear_handle(int fd OVS_UNUSED, HANDLE wevent OVS_UNUSED)
1453 WSAEventSelect(fd, NULL, 0);
1456 CloseHandle(wevent);