2 * Copyright (c) 2008, 2009, 2010, 2011, 2012 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"
25 #include <sys/types.h>
26 #include <sys/socket.h>
27 #include <netinet/tcp.h>
28 #include <openssl/err.h>
29 #include <openssl/rand.h>
30 #include <openssl/ssl.h>
31 #include <openssl/x509v3.h>
33 #include <sys/fcntl.h>
37 #include "dynamic-string.h"
39 #include "leak-checker.h"
41 #include "openflow/openflow.h"
43 #include "poll-loop.h"
45 #include "socket-util.h"
47 #include "stream-provider.h"
52 VLOG_DEFINE_THIS_MODULE(stream_ssl);
70 enum session_type type;
74 unsigned int session_nr;
76 /* rx_want and tx_want record the result of the last call to SSL_read()
77 * and SSL_write(), respectively:
79 * - If the call reported that data needed to be read from the file
80 * descriptor, the corresponding member is set to SSL_READING.
82 * - If the call reported that data needed to be written to the file
83 * descriptor, the corresponding member is set to SSL_WRITING.
85 * - Otherwise, the member is set to SSL_NOTHING, indicating that the
86 * call completed successfully (or with an error) and that there is no
89 * These are needed because there is no way to ask OpenSSL what a data read
90 * or write would require without giving it a buffer to receive into or
91 * data to send, respectively. (Note that the SSL_want() status is
92 * overwritten by each SSL_read() or SSL_write() call, so we can't rely on
95 * A single call to SSL_read() or SSL_write() can perform both reading
96 * and writing and thus invalidate not one of these values but actually
97 * both. Consider this situation, for example:
99 * - SSL_write() blocks on a read, so tx_want gets SSL_READING.
101 * - SSL_read() laters succeeds reading from 'fd' and clears out the
102 * whole receive buffer, so rx_want gets SSL_READING.
104 * - Client calls stream_wait(STREAM_RECV) and stream_wait(STREAM_SEND)
107 * - Now we're stuck blocking until the peer sends us data, even though
108 * SSL_write() could now succeed, which could easily be a deadlock
111 * On the other hand, we can't reset both tx_want and rx_want on every call
112 * to SSL_read() or SSL_write(), because that would produce livelock,
113 * e.g. in this situation:
115 * - SSL_write() blocks, so tx_want gets SSL_READING or SSL_WRITING.
117 * - SSL_read() blocks, so rx_want gets SSL_READING or SSL_WRITING,
118 * but tx_want gets reset to SSL_NOTHING.
120 * - Client calls stream_wait(STREAM_RECV) and stream_wait(STREAM_SEND)
123 * - Client wakes up immediately since SSL_NOTHING in tx_want indicates
124 * that no blocking is necessary.
126 * The solution we adopt here is to set tx_want to SSL_NOTHING after
127 * calling SSL_read() only if the SSL state of the connection changed,
128 * which indicates that an SSL-level renegotiation made some progress, and
129 * similarly for rx_want and SSL_write(). This prevents both the
130 * deadlock and livelock situations above.
132 int rx_want, tx_want;
134 /* A few bytes of header data in case SSL negotiation fails. */
139 /* SSL context created by ssl_init(). */
142 struct ssl_config_file {
143 bool read; /* Whether the file was successfully read. */
144 char *file_name; /* Configured file name, if any. */
145 struct timespec mtime; /* File mtime as of last time we read it. */
148 /* SSL configuration files. */
149 static struct ssl_config_file private_key;
150 static struct ssl_config_file certificate;
151 static struct ssl_config_file ca_cert;
153 /* Ordinarily, the SSL client and server verify each other's certificates using
154 * a CA certificate. Setting this to false disables this behavior. (This is a
156 static bool verify_peer_cert = true;
158 /* Ordinarily, we require a CA certificate for the peer to be locally
159 * available. We can, however, bootstrap the CA certificate from the peer at
160 * the beginning of our first connection then use that certificate on all
161 * subsequent connections, saving it to a file for use in future runs also. In
162 * this case, 'bootstrap_ca_cert' is true. */
163 static bool bootstrap_ca_cert;
165 /* Session number. Used in debug logging messages to uniquely identify a
167 static unsigned int next_session_nr;
169 /* Who knows what can trigger various SSL errors, so let's throttle them down
171 static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(10, 25);
173 static int ssl_init(void);
174 static int do_ssl_init(void);
175 static bool ssl_wants_io(int ssl_error);
176 static void ssl_close(struct stream *);
177 static void ssl_clear_txbuf(struct ssl_stream *);
178 static void interpret_queued_ssl_error(const char *function);
179 static int interpret_ssl_error(const char *function, int ret, int error,
181 static DH *tmp_dh_callback(SSL *ssl, int is_export OVS_UNUSED, int keylength);
182 static void log_ca_cert(const char *file_name, X509 *cert);
183 static void stream_ssl_set_ca_cert_file__(const char *file_name,
184 bool bootstrap, bool force);
185 static void ssl_protocol_cb(int write_p, int version, int content_type,
186 const void *, size_t, SSL *, void *sslv_);
187 static bool update_ssl_config(struct ssl_config_file *, const char *file_name);
190 want_to_poll_events(int want)
208 new_ssl_stream(const char *name, int fd, enum session_type type,
209 enum ssl_state state, const struct sockaddr_in *remote,
210 struct stream **streamp)
212 struct sockaddr_in local;
213 socklen_t local_len = sizeof local;
214 struct ssl_stream *sslv;
219 /* Check for all the needful configuration. */
221 if (!private_key.read) {
222 VLOG_ERR("Private key must be configured to use SSL");
223 retval = ENOPROTOOPT;
225 if (!certificate.read) {
226 VLOG_ERR("Certificate must be configured to use SSL");
227 retval = ENOPROTOOPT;
229 if (!ca_cert.read && verify_peer_cert && !bootstrap_ca_cert) {
230 VLOG_ERR("CA certificate must be configured to use SSL");
231 retval = ENOPROTOOPT;
233 if (!retval && !SSL_CTX_check_private_key(ctx)) {
234 VLOG_ERR("Private key does not match certificate public key: %s",
235 ERR_error_string(ERR_get_error(), NULL));
236 retval = ENOPROTOOPT;
242 /* Get the local IP and port information */
243 retval = getsockname(fd, (struct sockaddr *) &local, &local_len);
245 memset(&local, 0, sizeof local);
249 retval = setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &on, sizeof on);
251 VLOG_ERR("%s: setsockopt(TCP_NODELAY): %s", name, strerror(errno));
256 /* Create and configure OpenSSL stream. */
259 VLOG_ERR("SSL_new: %s", ERR_error_string(ERR_get_error(), NULL));
260 retval = ENOPROTOOPT;
263 if (SSL_set_fd(ssl, fd) == 0) {
264 VLOG_ERR("SSL_set_fd: %s", ERR_error_string(ERR_get_error(), NULL));
265 retval = ENOPROTOOPT;
268 if (!verify_peer_cert || (bootstrap_ca_cert && type == CLIENT)) {
269 SSL_set_verify(ssl, SSL_VERIFY_NONE, NULL);
272 /* Create and return the ssl_stream. */
273 sslv = xmalloc(sizeof *sslv);
274 stream_init(&sslv->stream, &ssl_stream_class, EAGAIN, name);
275 stream_set_remote_ip(&sslv->stream, remote->sin_addr.s_addr);
276 stream_set_remote_port(&sslv->stream, remote->sin_port);
277 stream_set_local_ip(&sslv->stream, local.sin_addr.s_addr);
278 stream_set_local_port(&sslv->stream, local.sin_port);
284 sslv->rx_want = sslv->tx_want = SSL_NOTHING;
285 sslv->session_nr = next_session_nr++;
288 if (VLOG_IS_DBG_ENABLED()) {
289 SSL_set_msg_callback(ssl, ssl_protocol_cb);
290 SSL_set_msg_callback_arg(ssl, sslv);
293 *streamp = &sslv->stream;
304 static struct ssl_stream *
305 ssl_stream_cast(struct stream *stream)
307 stream_assert_class(stream, &ssl_stream_class);
308 return CONTAINER_OF(stream, struct ssl_stream, stream);
312 ssl_open(const char *name, char *suffix, struct stream **streamp, uint8_t dscp)
314 struct sockaddr_in sin;
322 error = inet_open_active(SOCK_STREAM, suffix, OFP_SSL_PORT, &sin, &fd,
325 int state = error ? STATE_TCP_CONNECTING : STATE_SSL_CONNECTING;
326 return new_ssl_stream(name, fd, CLIENT, state, &sin, streamp);
328 VLOG_ERR("%s: connect: %s", name, strerror(error));
334 do_ca_cert_bootstrap(struct stream *stream)
336 struct ssl_stream *sslv = ssl_stream_cast(stream);
337 STACK_OF(X509) *chain;
343 chain = SSL_get_peer_cert_chain(sslv->ssl);
344 if (!chain || !sk_X509_num(chain)) {
345 VLOG_ERR("could not bootstrap CA cert: no certificate presented by "
349 cert = sk_X509_value(chain, sk_X509_num(chain) - 1);
351 /* Check that 'cert' is self-signed. Otherwise it is not a CA
352 * certificate and we should not attempt to use it as one. */
353 error = X509_check_issued(cert, cert);
355 VLOG_ERR("could not bootstrap CA cert: obtained certificate is "
356 "not self-signed (%s)",
357 X509_verify_cert_error_string(error));
358 if (sk_X509_num(chain) < 2) {
359 VLOG_ERR("only one certificate was received, so probably the peer "
360 "is not configured to send its CA certificate");
365 fd = open(ca_cert.file_name, O_CREAT | O_EXCL | O_WRONLY, 0444);
367 if (errno == EEXIST) {
368 VLOG_INFO_RL(&rl, "reading CA cert %s created by another process",
370 stream_ssl_set_ca_cert_file__(ca_cert.file_name, true, true);
373 VLOG_ERR("could not bootstrap CA cert: creating %s failed: %s",
374 ca_cert.file_name, strerror(errno));
379 file = fdopen(fd, "w");
382 VLOG_ERR("could not bootstrap CA cert: fdopen failed: %s",
384 unlink(ca_cert.file_name);
388 if (!PEM_write_X509(file, cert)) {
389 VLOG_ERR("could not bootstrap CA cert: PEM_write_X509 to %s failed: "
390 "%s", ca_cert.file_name,
391 ERR_error_string(ERR_get_error(), NULL));
393 unlink(ca_cert.file_name);
399 VLOG_ERR("could not bootstrap CA cert: writing %s failed: %s",
400 ca_cert.file_name, strerror(error));
401 unlink(ca_cert.file_name);
405 VLOG_INFO("successfully bootstrapped CA cert to %s", ca_cert.file_name);
406 log_ca_cert(ca_cert.file_name, cert);
407 bootstrap_ca_cert = false;
410 /* SSL_CTX_add_client_CA makes a copy of cert's relevant data. */
411 SSL_CTX_add_client_CA(ctx, cert);
413 /* SSL_CTX_use_certificate() takes ownership of the certificate passed in.
414 * 'cert' is owned by sslv->ssl, so we need to duplicate it. */
415 cert = X509_dup(cert);
419 SSL_CTX_set_cert_store(ctx, X509_STORE_new());
420 if (SSL_CTX_load_verify_locations(ctx, ca_cert.file_name, NULL) != 1) {
421 VLOG_ERR("SSL_CTX_load_verify_locations: %s",
422 ERR_error_string(ERR_get_error(), NULL));
425 VLOG_INFO("killing successful connection to retry using CA cert");
430 ssl_connect(struct stream *stream)
432 struct ssl_stream *sslv = ssl_stream_cast(stream);
435 switch (sslv->state) {
436 case STATE_TCP_CONNECTING:
437 retval = check_connection_completion(sslv->fd);
441 sslv->state = STATE_SSL_CONNECTING;
444 case STATE_SSL_CONNECTING:
445 /* Capture the first few bytes of received data so that we can guess
446 * what kind of funny data we've been sent if SSL negotation fails. */
447 if (sslv->n_head <= 0) {
448 sslv->n_head = recv(sslv->fd, sslv->head, sizeof sslv->head,
452 retval = (sslv->type == CLIENT
453 ? SSL_connect(sslv->ssl) : SSL_accept(sslv->ssl));
455 int error = SSL_get_error(sslv->ssl, retval);
456 if (retval < 0 && ssl_wants_io(error)) {
461 interpret_ssl_error((sslv->type == CLIENT ? "SSL_connect"
462 : "SSL_accept"), retval, error, &unused);
463 shutdown(sslv->fd, SHUT_RDWR);
464 stream_report_content(sslv->head, sslv->n_head, STREAM_SSL,
465 THIS_MODULE, stream_get_name(stream));
468 } else if (bootstrap_ca_cert) {
469 return do_ca_cert_bootstrap(stream);
470 } else if (verify_peer_cert
471 && ((SSL_get_verify_mode(sslv->ssl)
472 & (SSL_VERIFY_NONE | SSL_VERIFY_PEER))
473 != SSL_VERIFY_PEER)) {
474 /* Two or more SSL connections completed at the same time while we
475 * were in bootstrap mode. Only one of these can finish the
476 * bootstrap successfully. The other one(s) must be rejected
477 * because they were not verified against the bootstrapped CA
478 * certificate. (Alternatively we could verify them against the CA
479 * certificate, but that's more trouble than it's worth. These
480 * connections will succeed the next time they retry, assuming that
481 * they have a certificate against the correct CA.) */
482 VLOG_INFO("rejecting SSL connection during bootstrap race window");
493 ssl_close(struct stream *stream)
495 struct ssl_stream *sslv = ssl_stream_cast(stream);
496 ssl_clear_txbuf(sslv);
498 /* Attempt clean shutdown of the SSL connection. This will work most of
499 * the time, as long as the kernel send buffer has some free space and the
500 * SSL connection isn't renegotiating, etc. That has to be good enough,
501 * since we don't have any way to continue the close operation in the
503 SSL_shutdown(sslv->ssl);
505 /* SSL_shutdown() might have signaled an error, in which case we need to
506 * flush it out of the OpenSSL error queue or the next OpenSSL operation
507 * will falsely signal an error. */
516 interpret_queued_ssl_error(const char *function)
518 int queued_error = ERR_get_error();
519 if (queued_error != 0) {
520 VLOG_WARN_RL(&rl, "%s: %s",
521 function, ERR_error_string(queued_error, NULL));
523 VLOG_ERR_RL(&rl, "%s: SSL_ERROR_SSL without queued error", function);
528 interpret_ssl_error(const char *function, int ret, int error,
535 VLOG_ERR_RL(&rl, "%s: unexpected SSL_ERROR_NONE", function);
538 case SSL_ERROR_ZERO_RETURN:
539 VLOG_ERR_RL(&rl, "%s: unexpected SSL_ERROR_ZERO_RETURN", function);
542 case SSL_ERROR_WANT_READ:
546 case SSL_ERROR_WANT_WRITE:
550 case SSL_ERROR_WANT_CONNECT:
551 VLOG_ERR_RL(&rl, "%s: unexpected SSL_ERROR_WANT_CONNECT", function);
554 case SSL_ERROR_WANT_ACCEPT:
555 VLOG_ERR_RL(&rl, "%s: unexpected SSL_ERROR_WANT_ACCEPT", function);
558 case SSL_ERROR_WANT_X509_LOOKUP:
559 VLOG_ERR_RL(&rl, "%s: unexpected SSL_ERROR_WANT_X509_LOOKUP",
563 case SSL_ERROR_SYSCALL: {
564 int queued_error = ERR_get_error();
565 if (queued_error == 0) {
568 VLOG_WARN_RL(&rl, "%s: system error (%s)",
569 function, strerror(status));
572 VLOG_WARN_RL(&rl, "%s: unexpected SSL connection close",
577 VLOG_WARN_RL(&rl, "%s: %s",
578 function, ERR_error_string(queued_error, NULL));
584 interpret_queued_ssl_error(function);
588 VLOG_ERR_RL(&rl, "%s: bad SSL error code %d", function, error);
595 ssl_recv(struct stream *stream, void *buffer, size_t n)
597 struct ssl_stream *sslv = ssl_stream_cast(stream);
601 /* Behavior of zero-byte SSL_read is poorly defined. */
604 old_state = SSL_get_state(sslv->ssl);
605 ret = SSL_read(sslv->ssl, buffer, n);
606 if (old_state != SSL_get_state(sslv->ssl)) {
607 sslv->tx_want = SSL_NOTHING;
609 sslv->rx_want = SSL_NOTHING;
614 int error = SSL_get_error(sslv->ssl, ret);
615 if (error == SSL_ERROR_ZERO_RETURN) {
618 return -interpret_ssl_error("SSL_read", ret, error,
625 ssl_clear_txbuf(struct ssl_stream *sslv)
627 ofpbuf_delete(sslv->txbuf);
632 ssl_do_tx(struct stream *stream)
634 struct ssl_stream *sslv = ssl_stream_cast(stream);
637 int old_state = SSL_get_state(sslv->ssl);
638 int ret = SSL_write(sslv->ssl, sslv->txbuf->data, sslv->txbuf->size);
639 if (old_state != SSL_get_state(sslv->ssl)) {
640 sslv->rx_want = SSL_NOTHING;
642 sslv->tx_want = SSL_NOTHING;
644 ofpbuf_pull(sslv->txbuf, ret);
645 if (sslv->txbuf->size == 0) {
649 int ssl_error = SSL_get_error(sslv->ssl, ret);
650 if (ssl_error == SSL_ERROR_ZERO_RETURN) {
651 VLOG_WARN_RL(&rl, "SSL_write: connection closed");
654 return interpret_ssl_error("SSL_write", ret, ssl_error,
662 ssl_send(struct stream *stream, const void *buffer, size_t n)
664 struct ssl_stream *sslv = ssl_stream_cast(stream);
671 sslv->txbuf = ofpbuf_clone_data(buffer, n);
672 error = ssl_do_tx(stream);
675 ssl_clear_txbuf(sslv);
678 leak_checker_claim(buffer);
688 ssl_run(struct stream *stream)
690 struct ssl_stream *sslv = ssl_stream_cast(stream);
692 if (sslv->txbuf && ssl_do_tx(stream) != EAGAIN) {
693 ssl_clear_txbuf(sslv);
698 ssl_run_wait(struct stream *stream)
700 struct ssl_stream *sslv = ssl_stream_cast(stream);
702 if (sslv->tx_want != SSL_NOTHING) {
703 poll_fd_wait(sslv->fd, want_to_poll_events(sslv->tx_want));
708 ssl_wait(struct stream *stream, enum stream_wait_type wait)
710 struct ssl_stream *sslv = ssl_stream_cast(stream);
714 if (stream_connect(stream) != EAGAIN) {
715 poll_immediate_wake();
717 switch (sslv->state) {
718 case STATE_TCP_CONNECTING:
719 poll_fd_wait(sslv->fd, POLLOUT);
722 case STATE_SSL_CONNECTING:
723 /* ssl_connect() called SSL_accept() or SSL_connect(), which
724 * set up the status that we test here. */
725 poll_fd_wait(sslv->fd,
726 want_to_poll_events(SSL_want(sslv->ssl)));
736 if (sslv->rx_want != SSL_NOTHING) {
737 poll_fd_wait(sslv->fd, want_to_poll_events(sslv->rx_want));
739 poll_immediate_wake();
745 /* We have room in our tx queue. */
746 poll_immediate_wake();
748 /* stream_run_wait() will do the right thing; don't bother with
758 const struct stream_class ssl_stream_class = {
760 true, /* needs_probes */
762 ssl_close, /* close */
763 ssl_connect, /* connect */
767 ssl_run_wait, /* run_wait */
775 struct pstream pstream;
779 const struct pstream_class pssl_pstream_class;
781 static struct pssl_pstream *
782 pssl_pstream_cast(struct pstream *pstream)
784 pstream_assert_class(pstream, &pssl_pstream_class);
785 return CONTAINER_OF(pstream, struct pssl_pstream, pstream);
789 pssl_open(const char *name OVS_UNUSED, char *suffix, struct pstream **pstreamp,
792 struct pssl_pstream *pssl;
793 struct sockaddr_in sin;
794 char bound_name[128];
803 fd = inet_open_passive(SOCK_STREAM, suffix, OFP_SSL_PORT, &sin, dscp);
807 sprintf(bound_name, "pssl:%"PRIu16":"IP_FMT,
808 ntohs(sin.sin_port), IP_ARGS(sin.sin_addr.s_addr));
810 pssl = xmalloc(sizeof *pssl);
811 pstream_init(&pssl->pstream, &pssl_pstream_class, bound_name);
813 *pstreamp = &pssl->pstream;
818 pssl_close(struct pstream *pstream)
820 struct pssl_pstream *pssl = pssl_pstream_cast(pstream);
826 pssl_accept(struct pstream *pstream, struct stream **new_streamp)
828 struct pssl_pstream *pssl = pssl_pstream_cast(pstream);
829 struct sockaddr_in sin;
830 socklen_t sin_len = sizeof sin;
835 new_fd = accept(pssl->fd, (struct sockaddr *) &sin, &sin_len);
838 if (error != EAGAIN) {
839 VLOG_DBG_RL(&rl, "accept: %s", strerror(error));
844 error = set_nonblocking(new_fd);
850 sprintf(name, "ssl:"IP_FMT, IP_ARGS(sin.sin_addr.s_addr));
851 if (sin.sin_port != htons(OFP_SSL_PORT)) {
852 sprintf(strchr(name, '\0'), ":%"PRIu16, ntohs(sin.sin_port));
854 return new_ssl_stream(name, new_fd, SERVER, STATE_SSL_CONNECTING, &sin,
859 pssl_wait(struct pstream *pstream)
861 struct pssl_pstream *pssl = pssl_pstream_cast(pstream);
862 poll_fd_wait(pssl->fd, POLLIN);
866 pssl_set_dscp(struct pstream *pstream, uint8_t dscp)
868 struct pssl_pstream *pssl = pssl_pstream_cast(pstream);
869 return set_dscp(pssl->fd, dscp);
872 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 assert(init_status >= 0);
911 SSL_load_error_strings();
913 if (!RAND_status()) {
914 /* We occasionally see OpenSSL fail to seed its random number generator
915 * in heavily loaded hypervisors. I suspect the following scenario:
917 * 1. OpenSSL calls read() to get 32 bytes from /dev/urandom.
918 * 2. The kernel generates 10 bytes of randomness and copies it out.
919 * 3. A signal arrives (perhaps SIGALRM).
920 * 4. The kernel interrupts the system call to service the signal.
921 * 5. Userspace gets 10 bytes of entropy.
922 * 6. OpenSSL doesn't read again to get the final 22 bytes. Therefore
923 * OpenSSL doesn't have enough entropy to consider itself
926 * The only part I'm not entirely sure about is #6, because the OpenSSL
927 * code is so hard to read. */
931 VLOG_WARN("OpenSSL random seeding failed, reseeding ourselves");
933 retval = get_entropy(seed, sizeof seed);
935 VLOG_ERR("failed to obtain entropy (%s)",
936 ovs_retval_to_string(retval));
937 return retval > 0 ? retval : ENOPROTOOPT;
940 RAND_seed(seed, sizeof seed);
943 /* New OpenSSL changed TLSv1_method() to return a "const" pointer, so the
944 * cast is needed to avoid a warning with those newer versions. */
945 method = CONST_CAST(SSL_METHOD *, TLSv1_method());
946 if (method == NULL) {
947 VLOG_ERR("TLSv1_method: %s", ERR_error_string(ERR_get_error(), NULL));
951 ctx = SSL_CTX_new(method);
953 VLOG_ERR("SSL_CTX_new: %s", ERR_error_string(ERR_get_error(), NULL));
956 SSL_CTX_set_options(ctx, SSL_OP_NO_SSLv2 | SSL_OP_NO_SSLv3);
957 SSL_CTX_set_tmp_dh_callback(ctx, tmp_dh_callback);
958 SSL_CTX_set_mode(ctx, SSL_MODE_ENABLE_PARTIAL_WRITE);
959 SSL_CTX_set_mode(ctx, SSL_MODE_ACCEPT_MOVING_WRITE_BUFFER);
960 SSL_CTX_set_verify(ctx, SSL_VERIFY_PEER | SSL_VERIFY_FAIL_IF_NO_PEER_CERT,
967 tmp_dh_callback(SSL *ssl OVS_UNUSED, int is_export OVS_UNUSED, int keylength)
972 DH *(*constructor)(void);
975 static struct dh dh_table[] = {
976 {1024, NULL, get_dh1024},
977 {2048, NULL, get_dh2048},
978 {4096, NULL, get_dh4096},
983 for (dh = dh_table; dh < &dh_table[ARRAY_SIZE(dh_table)]; dh++) {
984 if (dh->keylength == keylength) {
986 dh->dh = dh->constructor();
994 VLOG_ERR_RL(&rl, "no Diffie-Hellman parameters for key length %d",
999 /* Returns true if SSL is at least partially configured. */
1001 stream_ssl_is_configured(void)
1003 return private_key.file_name || certificate.file_name || ca_cert.file_name;
1007 update_ssl_config(struct ssl_config_file *config, const char *file_name)
1009 struct timespec mtime;
1012 if (ssl_init() || !file_name) {
1016 /* If the file name hasn't changed and neither has the file contents, stop
1018 error = get_mtime(file_name, &mtime);
1019 if (error && error != ENOENT) {
1020 VLOG_ERR_RL(&rl, "%s: stat failed (%s)", file_name, strerror(error));
1022 if (config->file_name
1023 && !strcmp(config->file_name, file_name)
1024 && mtime.tv_sec == config->mtime.tv_sec
1025 && mtime.tv_nsec == config->mtime.tv_nsec) {
1029 /* Update 'config'. */
1030 config->mtime = mtime;
1031 if (file_name != config->file_name) {
1032 free(config->file_name);
1033 config->file_name = xstrdup(file_name);
1039 stream_ssl_set_private_key_file__(const char *file_name)
1041 if (SSL_CTX_use_PrivateKey_file(ctx, file_name, SSL_FILETYPE_PEM) == 1) {
1042 private_key.read = true;
1044 VLOG_ERR("SSL_use_PrivateKey_file: %s",
1045 ERR_error_string(ERR_get_error(), NULL));
1050 stream_ssl_set_private_key_file(const char *file_name)
1052 if (update_ssl_config(&private_key, file_name)) {
1053 stream_ssl_set_private_key_file__(file_name);
1058 stream_ssl_set_certificate_file__(const char *file_name)
1060 if (SSL_CTX_use_certificate_chain_file(ctx, file_name) == 1) {
1061 certificate.read = true;
1063 VLOG_ERR("SSL_use_certificate_file: %s",
1064 ERR_error_string(ERR_get_error(), NULL));
1069 stream_ssl_set_certificate_file(const char *file_name)
1071 if (update_ssl_config(&certificate, file_name)) {
1072 stream_ssl_set_certificate_file__(file_name);
1076 /* Sets the private key and certificate files in one operation. Use this
1077 * interface, instead of calling stream_ssl_set_private_key_file() and
1078 * stream_ssl_set_certificate_file() individually, in the main loop of a
1079 * long-running program whose key and certificate might change at runtime.
1081 * This is important because of OpenSSL's behavior. If an OpenSSL context
1082 * already has a certificate, and stream_ssl_set_private_key_file() is called
1083 * to install a new private key, OpenSSL will report an error because the new
1084 * private key does not match the old certificate. The other order, of setting
1085 * a new certificate, then setting a new private key, does work.
1087 * If this were the only problem, calling stream_ssl_set_certificate_file()
1088 * before stream_ssl_set_private_key_file() would fix it. But, if the private
1089 * key is changed before the certificate (e.g. someone "scp"s or "mv"s the new
1090 * private key in place before the certificate), then OpenSSL would reject that
1091 * change, and then the change of certificate would succeed, but there would be
1092 * no associated private key (because it had only changed once and therefore
1093 * there was no point in re-reading it).
1095 * This function avoids both problems by, whenever either the certificate or
1096 * the private key file changes, re-reading both of them, in the correct order.
1099 stream_ssl_set_key_and_cert(const char *private_key_file,
1100 const char *certificate_file)
1102 if (update_ssl_config(&private_key, private_key_file)
1103 || update_ssl_config(&certificate, certificate_file)) {
1104 stream_ssl_set_certificate_file__(certificate_file);
1105 stream_ssl_set_private_key_file__(private_key_file);
1109 /* Reads the X509 certificate or certificates in file 'file_name'. On success,
1110 * stores the address of the first element in an array of pointers to
1111 * certificates in '*certs' and the number of certificates in the array in
1112 * '*n_certs', and returns 0. On failure, stores a null pointer in '*certs', 0
1113 * in '*n_certs', and returns a positive errno value.
1115 * The caller is responsible for freeing '*certs'. */
1117 read_cert_file(const char *file_name, X509 ***certs, size_t *n_certs)
1120 size_t allocated_certs = 0;
1125 file = fopen(file_name, "r");
1127 VLOG_ERR("failed to open %s for reading: %s",
1128 file_name, strerror(errno));
1136 /* Read certificate from file. */
1137 certificate = PEM_read_X509(file, NULL, NULL, NULL);
1141 VLOG_ERR("PEM_read_X509 failed reading %s: %s",
1142 file_name, ERR_error_string(ERR_get_error(), NULL));
1143 for (i = 0; i < *n_certs; i++) {
1144 X509_free((*certs)[i]);
1152 /* Add certificate to array. */
1153 if (*n_certs >= allocated_certs) {
1154 *certs = x2nrealloc(*certs, &allocated_certs, sizeof **certs);
1156 (*certs)[(*n_certs)++] = certificate;
1158 /* Are there additional certificates in the file? */
1161 } while (isspace(c));
1172 /* Sets 'file_name' as the name of a file containing one or more X509
1173 * certificates to send to the peer. Typical use in OpenFlow is to send the CA
1174 * certificate to the peer, which enables a switch to pick up the controller's
1175 * CA certificate on its first connection. */
1177 stream_ssl_set_peer_ca_cert_file(const char *file_name)
1187 if (!read_cert_file(file_name, &certs, &n_certs)) {
1188 for (i = 0; i < n_certs; i++) {
1189 if (SSL_CTX_add_extra_chain_cert(ctx, certs[i]) != 1) {
1190 VLOG_ERR("SSL_CTX_add_extra_chain_cert: %s",
1191 ERR_error_string(ERR_get_error(), NULL));
1198 /* Logs fingerprint of CA certificate 'cert' obtained from 'file_name'. */
1200 log_ca_cert(const char *file_name, X509 *cert)
1202 unsigned char digest[EVP_MAX_MD_SIZE];
1203 unsigned int n_bytes;
1208 if (!X509_digest(cert, EVP_sha1(), digest, &n_bytes)) {
1209 ds_put_cstr(&fp, "<out of memory>");
1212 for (i = 0; i < n_bytes; i++) {
1214 ds_put_char(&fp, ':');
1216 ds_put_format(&fp, "%02hhx", digest[i]);
1219 subject = X509_NAME_oneline(X509_get_subject_name(cert), NULL, 0);
1220 VLOG_INFO("Trusting CA cert from %s (%s) (fingerprint %s)", file_name,
1221 subject ? subject : "<out of memory>", ds_cstr(&fp));
1222 OPENSSL_free(subject);
1227 stream_ssl_set_ca_cert_file__(const char *file_name,
1228 bool bootstrap, bool force)
1234 if (!update_ssl_config(&ca_cert, file_name) && !force) {
1238 if (!strcmp(file_name, "none")) {
1239 verify_peer_cert = false;
1240 VLOG_WARN("Peer certificate validation disabled "
1241 "(this is a security risk)");
1242 } else if (bootstrap && stat(file_name, &s) && errno == ENOENT) {
1243 bootstrap_ca_cert = true;
1244 } else if (!read_cert_file(file_name, &certs, &n_certs)) {
1247 /* Set up list of CAs that the server will accept from the client. */
1248 for (i = 0; i < n_certs; i++) {
1249 /* SSL_CTX_add_client_CA makes a copy of the relevant data. */
1250 if (SSL_CTX_add_client_CA(ctx, certs[i]) != 1) {
1251 VLOG_ERR("failed to add client certificate %zu from %s: %s",
1253 ERR_error_string(ERR_get_error(), NULL));
1255 log_ca_cert(file_name, certs[i]);
1257 X509_free(certs[i]);
1261 /* Set up CAs for OpenSSL to trust in verifying the peer's
1263 SSL_CTX_set_cert_store(ctx, X509_STORE_new());
1264 if (SSL_CTX_load_verify_locations(ctx, file_name, NULL) != 1) {
1265 VLOG_ERR("SSL_CTX_load_verify_locations: %s",
1266 ERR_error_string(ERR_get_error(), NULL));
1270 bootstrap_ca_cert = false;
1272 ca_cert.read = true;
1275 /* Sets 'file_name' as the name of the file from which to read the CA
1276 * certificate used to verify the peer within SSL connections. If 'bootstrap'
1277 * is false, the file must exist. If 'bootstrap' is false, then the file is
1278 * read if it is exists; if it does not, then it will be created from the CA
1279 * certificate received from the peer on the first SSL connection. */
1281 stream_ssl_set_ca_cert_file(const char *file_name, bool bootstrap)
1283 stream_ssl_set_ca_cert_file__(file_name, bootstrap, false);
1286 /* SSL protocol logging. */
1289 ssl_alert_level_to_string(uint8_t type)
1292 case 1: return "warning";
1293 case 2: return "fatal";
1294 default: return "<unknown>";
1299 ssl_alert_description_to_string(uint8_t type)
1302 case 0: return "close_notify";
1303 case 10: return "unexpected_message";
1304 case 20: return "bad_record_mac";
1305 case 21: return "decryption_failed";
1306 case 22: return "record_overflow";
1307 case 30: return "decompression_failure";
1308 case 40: return "handshake_failure";
1309 case 42: return "bad_certificate";
1310 case 43: return "unsupported_certificate";
1311 case 44: return "certificate_revoked";
1312 case 45: return "certificate_expired";
1313 case 46: return "certificate_unknown";
1314 case 47: return "illegal_parameter";
1315 case 48: return "unknown_ca";
1316 case 49: return "access_denied";
1317 case 50: return "decode_error";
1318 case 51: return "decrypt_error";
1319 case 60: return "export_restriction";
1320 case 70: return "protocol_version";
1321 case 71: return "insufficient_security";
1322 case 80: return "internal_error";
1323 case 90: return "user_canceled";
1324 case 100: return "no_renegotiation";
1325 default: return "<unknown>";
1330 ssl_handshake_type_to_string(uint8_t type)
1333 case 0: return "hello_request";
1334 case 1: return "client_hello";
1335 case 2: return "server_hello";
1336 case 11: return "certificate";
1337 case 12: return "server_key_exchange";
1338 case 13: return "certificate_request";
1339 case 14: return "server_hello_done";
1340 case 15: return "certificate_verify";
1341 case 16: return "client_key_exchange";
1342 case 20: return "finished";
1343 default: return "<unknown>";
1348 ssl_protocol_cb(int write_p, int version OVS_UNUSED, int content_type,
1349 const void *buf_, size_t len, SSL *ssl OVS_UNUSED, void *sslv_)
1351 const struct ssl_stream *sslv = sslv_;
1352 const uint8_t *buf = buf_;
1355 if (!VLOG_IS_DBG_ENABLED()) {
1360 if (content_type == 20) {
1361 ds_put_cstr(&details, "change_cipher_spec");
1362 } else if (content_type == 21) {
1363 ds_put_format(&details, "alert: %s, %s",
1364 ssl_alert_level_to_string(buf[0]),
1365 ssl_alert_description_to_string(buf[1]));
1366 } else if (content_type == 22) {
1367 ds_put_format(&details, "handshake: %s",
1368 ssl_handshake_type_to_string(buf[0]));
1370 ds_put_format(&details, "type %d", content_type);
1373 VLOG_DBG("%s%u%s%s %s (%zu bytes)",
1374 sslv->type == CLIENT ? "client" : "server",
1375 sslv->session_nr, write_p ? "-->" : "<--",
1376 stream_get_name(&sslv->stream), ds_cstr(&details), len);
1378 ds_destroy(&details);