2 * Copyright (c) 2008, 2009, 2010, 2011, 2012, 2013 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>
32 #include <sys/fcntl.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"
50 VLOG_DEFINE_THIS_MODULE(stream_ssl);
68 enum session_type type;
72 unsigned int session_nr;
74 /* rx_want and tx_want record the result of the last call to SSL_read()
75 * and SSL_write(), respectively:
77 * - If the call reported that data needed to be read from the file
78 * descriptor, the corresponding member is set to SSL_READING.
80 * - If the call reported that data needed to be written to the file
81 * descriptor, the corresponding member is set to SSL_WRITING.
83 * - Otherwise, the member is set to SSL_NOTHING, indicating that the
84 * call completed successfully (or with an error) and that there is no
87 * These are needed because there is no way to ask OpenSSL what a data read
88 * or write would require without giving it a buffer to receive into or
89 * data to send, respectively. (Note that the SSL_want() status is
90 * overwritten by each SSL_read() or SSL_write() call, so we can't rely on
93 * A single call to SSL_read() or SSL_write() can perform both reading
94 * and writing and thus invalidate not one of these values but actually
95 * both. Consider this situation, for example:
97 * - SSL_write() blocks on a read, so tx_want gets SSL_READING.
99 * - SSL_read() laters succeeds reading from 'fd' and clears out the
100 * whole receive buffer, so rx_want gets SSL_READING.
102 * - Client calls stream_wait(STREAM_RECV) and stream_wait(STREAM_SEND)
105 * - Now we're stuck blocking until the peer sends us data, even though
106 * SSL_write() could now succeed, which could easily be a deadlock
109 * On the other hand, we can't reset both tx_want and rx_want on every call
110 * to SSL_read() or SSL_write(), because that would produce livelock,
111 * e.g. in this situation:
113 * - SSL_write() blocks, so tx_want gets SSL_READING or SSL_WRITING.
115 * - SSL_read() blocks, so rx_want gets SSL_READING or SSL_WRITING,
116 * but tx_want gets reset to SSL_NOTHING.
118 * - Client calls stream_wait(STREAM_RECV) and stream_wait(STREAM_SEND)
121 * - Client wakes up immediately since SSL_NOTHING in tx_want indicates
122 * that no blocking is necessary.
124 * The solution we adopt here is to set tx_want to SSL_NOTHING after
125 * calling SSL_read() only if the SSL state of the connection changed,
126 * which indicates that an SSL-level renegotiation made some progress, and
127 * similarly for rx_want and SSL_write(). This prevents both the
128 * deadlock and livelock situations above.
130 int rx_want, tx_want;
132 /* A few bytes of header data in case SSL negotiation fails. */
137 /* SSL context created by ssl_init(). */
140 struct ssl_config_file {
141 bool read; /* Whether the file was successfully read. */
142 char *file_name; /* Configured file name, if any. */
143 struct timespec mtime; /* File mtime as of last time we read it. */
146 /* SSL configuration files. */
147 static struct ssl_config_file private_key;
148 static struct ssl_config_file certificate;
149 static struct ssl_config_file ca_cert;
151 /* Ordinarily, the SSL client and server verify each other's certificates using
152 * a CA certificate. Setting this to false disables this behavior. (This is a
154 static bool verify_peer_cert = true;
156 /* Ordinarily, we require a CA certificate for the peer to be locally
157 * available. We can, however, bootstrap the CA certificate from the peer at
158 * the beginning of our first connection then use that certificate on all
159 * subsequent connections, saving it to a file for use in future runs also. In
160 * this case, 'bootstrap_ca_cert' is true. */
161 static bool bootstrap_ca_cert;
163 /* Session number. Used in debug logging messages to uniquely identify a
165 static unsigned int next_session_nr;
167 /* Who knows what can trigger various SSL errors, so let's throttle them down
169 static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(10, 25);
171 static int ssl_init(void);
172 static int do_ssl_init(void);
173 static bool ssl_wants_io(int ssl_error);
174 static void ssl_close(struct stream *);
175 static void ssl_clear_txbuf(struct ssl_stream *);
176 static void interpret_queued_ssl_error(const char *function);
177 static int interpret_ssl_error(const char *function, int ret, int error,
179 static DH *tmp_dh_callback(SSL *ssl, int is_export OVS_UNUSED, int keylength);
180 static void log_ca_cert(const char *file_name, X509 *cert);
181 static void stream_ssl_set_ca_cert_file__(const char *file_name,
182 bool bootstrap, bool force);
183 static void ssl_protocol_cb(int write_p, int version, int content_type,
184 const void *, size_t, SSL *, void *sslv_);
185 static bool update_ssl_config(struct ssl_config_file *, const char *file_name);
188 want_to_poll_events(int want)
206 new_ssl_stream(const char *name, int fd, enum session_type type,
207 enum ssl_state state, struct stream **streamp)
209 struct sockaddr_in local;
210 socklen_t local_len = sizeof local;
211 struct ssl_stream *sslv;
216 /* Check for all the needful configuration. */
218 if (!private_key.read) {
219 VLOG_ERR("Private key must be configured to use SSL");
220 retval = ENOPROTOOPT;
222 if (!certificate.read) {
223 VLOG_ERR("Certificate must be configured to use SSL");
224 retval = ENOPROTOOPT;
226 if (!ca_cert.read && verify_peer_cert && !bootstrap_ca_cert) {
227 VLOG_ERR("CA certificate must be configured to use SSL");
228 retval = ENOPROTOOPT;
230 if (!retval && !SSL_CTX_check_private_key(ctx)) {
231 VLOG_ERR("Private key does not match certificate public key: %s",
232 ERR_error_string(ERR_get_error(), NULL));
233 retval = ENOPROTOOPT;
239 /* Get the local IP and port information */
240 retval = getsockname(fd, (struct sockaddr *) &local, &local_len);
242 memset(&local, 0, sizeof local);
246 retval = setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &on, sizeof on);
248 VLOG_ERR("%s: setsockopt(TCP_NODELAY): %s", name, ovs_strerror(errno));
253 /* Create and configure OpenSSL stream. */
256 VLOG_ERR("SSL_new: %s", ERR_error_string(ERR_get_error(), NULL));
257 retval = ENOPROTOOPT;
260 if (SSL_set_fd(ssl, fd) == 0) {
261 VLOG_ERR("SSL_set_fd: %s", ERR_error_string(ERR_get_error(), NULL));
262 retval = ENOPROTOOPT;
265 if (!verify_peer_cert || (bootstrap_ca_cert && type == CLIENT)) {
266 SSL_set_verify(ssl, SSL_VERIFY_NONE, NULL);
269 /* Create and return the ssl_stream. */
270 sslv = xmalloc(sizeof *sslv);
271 stream_init(&sslv->stream, &ssl_stream_class, EAGAIN, name);
277 sslv->rx_want = sslv->tx_want = SSL_NOTHING;
278 sslv->session_nr = next_session_nr++;
281 if (VLOG_IS_DBG_ENABLED()) {
282 SSL_set_msg_callback(ssl, ssl_protocol_cb);
283 SSL_set_msg_callback_arg(ssl, sslv);
286 *streamp = &sslv->stream;
297 static struct ssl_stream *
298 ssl_stream_cast(struct stream *stream)
300 stream_assert_class(stream, &ssl_stream_class);
301 return CONTAINER_OF(stream, struct ssl_stream, stream);
305 ssl_open(const char *name, char *suffix, struct stream **streamp, uint8_t dscp)
314 error = inet_open_active(SOCK_STREAM, suffix, OFP_OLD_PORT, NULL, &fd,
317 int state = error ? STATE_TCP_CONNECTING : STATE_SSL_CONNECTING;
318 return new_ssl_stream(name, fd, CLIENT, state, streamp);
320 VLOG_ERR("%s: connect: %s", name, ovs_strerror(error));
326 do_ca_cert_bootstrap(struct stream *stream)
328 struct ssl_stream *sslv = ssl_stream_cast(stream);
329 STACK_OF(X509) *chain;
335 chain = SSL_get_peer_cert_chain(sslv->ssl);
336 if (!chain || !sk_X509_num(chain)) {
337 VLOG_ERR("could not bootstrap CA cert: no certificate presented by "
341 cert = sk_X509_value(chain, sk_X509_num(chain) - 1);
343 /* Check that 'cert' is self-signed. Otherwise it is not a CA
344 * certificate and we should not attempt to use it as one. */
345 error = X509_check_issued(cert, cert);
347 VLOG_ERR("could not bootstrap CA cert: obtained certificate is "
348 "not self-signed (%s)",
349 X509_verify_cert_error_string(error));
350 if (sk_X509_num(chain) < 2) {
351 VLOG_ERR("only one certificate was received, so probably the peer "
352 "is not configured to send its CA certificate");
357 fd = open(ca_cert.file_name, O_CREAT | O_EXCL | O_WRONLY, 0444);
359 if (errno == EEXIST) {
360 VLOG_INFO_RL(&rl, "reading CA cert %s created by another process",
362 stream_ssl_set_ca_cert_file__(ca_cert.file_name, true, true);
365 VLOG_ERR("could not bootstrap CA cert: creating %s failed: %s",
366 ca_cert.file_name, ovs_strerror(errno));
371 file = fdopen(fd, "w");
374 VLOG_ERR("could not bootstrap CA cert: fdopen failed: %s",
375 ovs_strerror(error));
376 unlink(ca_cert.file_name);
380 if (!PEM_write_X509(file, cert)) {
381 VLOG_ERR("could not bootstrap CA cert: PEM_write_X509 to %s failed: "
382 "%s", ca_cert.file_name,
383 ERR_error_string(ERR_get_error(), NULL));
385 unlink(ca_cert.file_name);
391 VLOG_ERR("could not bootstrap CA cert: writing %s failed: %s",
392 ca_cert.file_name, ovs_strerror(error));
393 unlink(ca_cert.file_name);
397 VLOG_INFO("successfully bootstrapped CA cert to %s", ca_cert.file_name);
398 log_ca_cert(ca_cert.file_name, cert);
399 bootstrap_ca_cert = false;
402 /* SSL_CTX_add_client_CA makes a copy of cert's relevant data. */
403 SSL_CTX_add_client_CA(ctx, cert);
405 /* SSL_CTX_use_certificate() takes ownership of the certificate passed in.
406 * 'cert' is owned by sslv->ssl, so we need to duplicate it. */
407 cert = X509_dup(cert);
411 SSL_CTX_set_cert_store(ctx, X509_STORE_new());
412 if (SSL_CTX_load_verify_locations(ctx, ca_cert.file_name, NULL) != 1) {
413 VLOG_ERR("SSL_CTX_load_verify_locations: %s",
414 ERR_error_string(ERR_get_error(), NULL));
417 VLOG_INFO("killing successful connection to retry using CA cert");
422 ssl_connect(struct stream *stream)
424 struct ssl_stream *sslv = ssl_stream_cast(stream);
427 switch (sslv->state) {
428 case STATE_TCP_CONNECTING:
429 retval = check_connection_completion(sslv->fd);
433 sslv->state = STATE_SSL_CONNECTING;
436 case STATE_SSL_CONNECTING:
437 /* Capture the first few bytes of received data so that we can guess
438 * what kind of funny data we've been sent if SSL negotiation fails. */
439 if (sslv->n_head <= 0) {
440 sslv->n_head = recv(sslv->fd, sslv->head, sizeof sslv->head,
444 retval = (sslv->type == CLIENT
445 ? SSL_connect(sslv->ssl) : SSL_accept(sslv->ssl));
447 int error = SSL_get_error(sslv->ssl, retval);
448 if (retval < 0 && ssl_wants_io(error)) {
453 interpret_ssl_error((sslv->type == CLIENT ? "SSL_connect"
454 : "SSL_accept"), retval, error, &unused);
455 shutdown(sslv->fd, SHUT_RDWR);
456 stream_report_content(sslv->head, sslv->n_head, STREAM_SSL,
457 THIS_MODULE, stream_get_name(stream));
460 } else if (bootstrap_ca_cert) {
461 return do_ca_cert_bootstrap(stream);
462 } else if (verify_peer_cert
463 && ((SSL_get_verify_mode(sslv->ssl)
464 & (SSL_VERIFY_NONE | SSL_VERIFY_PEER))
465 != SSL_VERIFY_PEER)) {
466 /* Two or more SSL connections completed at the same time while we
467 * were in bootstrap mode. Only one of these can finish the
468 * bootstrap successfully. The other one(s) must be rejected
469 * because they were not verified against the bootstrapped CA
470 * certificate. (Alternatively we could verify them against the CA
471 * certificate, but that's more trouble than it's worth. These
472 * connections will succeed the next time they retry, assuming that
473 * they have a certificate against the correct CA.) */
474 VLOG_INFO("rejecting SSL connection during bootstrap race window");
485 ssl_close(struct stream *stream)
487 struct ssl_stream *sslv = ssl_stream_cast(stream);
488 ssl_clear_txbuf(sslv);
490 /* Attempt clean shutdown of the SSL connection. This will work most of
491 * the time, as long as the kernel send buffer has some free space and the
492 * SSL connection isn't renegotiating, etc. That has to be good enough,
493 * since we don't have any way to continue the close operation in the
495 SSL_shutdown(sslv->ssl);
497 /* SSL_shutdown() might have signaled an error, in which case we need to
498 * flush it out of the OpenSSL error queue or the next OpenSSL operation
499 * will falsely signal an error. */
508 interpret_queued_ssl_error(const char *function)
510 int queued_error = ERR_get_error();
511 if (queued_error != 0) {
512 VLOG_WARN_RL(&rl, "%s: %s",
513 function, ERR_error_string(queued_error, NULL));
515 VLOG_ERR_RL(&rl, "%s: SSL_ERROR_SSL without queued error", function);
520 interpret_ssl_error(const char *function, int ret, int error,
527 VLOG_ERR_RL(&rl, "%s: unexpected SSL_ERROR_NONE", function);
530 case SSL_ERROR_ZERO_RETURN:
531 VLOG_ERR_RL(&rl, "%s: unexpected SSL_ERROR_ZERO_RETURN", function);
534 case SSL_ERROR_WANT_READ:
538 case SSL_ERROR_WANT_WRITE:
542 case SSL_ERROR_WANT_CONNECT:
543 VLOG_ERR_RL(&rl, "%s: unexpected SSL_ERROR_WANT_CONNECT", function);
546 case SSL_ERROR_WANT_ACCEPT:
547 VLOG_ERR_RL(&rl, "%s: unexpected SSL_ERROR_WANT_ACCEPT", function);
550 case SSL_ERROR_WANT_X509_LOOKUP:
551 VLOG_ERR_RL(&rl, "%s: unexpected SSL_ERROR_WANT_X509_LOOKUP",
555 case SSL_ERROR_SYSCALL: {
556 int queued_error = ERR_get_error();
557 if (queued_error == 0) {
560 VLOG_WARN_RL(&rl, "%s: system error (%s)",
561 function, ovs_strerror(status));
564 VLOG_WARN_RL(&rl, "%s: unexpected SSL connection close",
569 VLOG_WARN_RL(&rl, "%s: %s",
570 function, ERR_error_string(queued_error, NULL));
576 interpret_queued_ssl_error(function);
580 VLOG_ERR_RL(&rl, "%s: bad SSL error code %d", function, error);
587 ssl_recv(struct stream *stream, void *buffer, size_t n)
589 struct ssl_stream *sslv = ssl_stream_cast(stream);
593 /* Behavior of zero-byte SSL_read is poorly defined. */
596 old_state = SSL_get_state(sslv->ssl);
597 ret = SSL_read(sslv->ssl, buffer, n);
598 if (old_state != SSL_get_state(sslv->ssl)) {
599 sslv->tx_want = SSL_NOTHING;
601 sslv->rx_want = SSL_NOTHING;
606 int error = SSL_get_error(sslv->ssl, ret);
607 if (error == SSL_ERROR_ZERO_RETURN) {
610 return -interpret_ssl_error("SSL_read", ret, error,
617 ssl_clear_txbuf(struct ssl_stream *sslv)
619 ofpbuf_delete(sslv->txbuf);
624 ssl_do_tx(struct stream *stream)
626 struct ssl_stream *sslv = ssl_stream_cast(stream);
629 int old_state = SSL_get_state(sslv->ssl);
630 int ret = SSL_write(sslv->ssl, sslv->txbuf->data, sslv->txbuf->size);
631 if (old_state != SSL_get_state(sslv->ssl)) {
632 sslv->rx_want = SSL_NOTHING;
634 sslv->tx_want = SSL_NOTHING;
636 ofpbuf_pull(sslv->txbuf, ret);
637 if (sslv->txbuf->size == 0) {
641 int ssl_error = SSL_get_error(sslv->ssl, ret);
642 if (ssl_error == SSL_ERROR_ZERO_RETURN) {
643 VLOG_WARN_RL(&rl, "SSL_write: connection closed");
646 return interpret_ssl_error("SSL_write", ret, ssl_error,
654 ssl_send(struct stream *stream, const void *buffer, size_t n)
656 struct ssl_stream *sslv = ssl_stream_cast(stream);
663 sslv->txbuf = ofpbuf_clone_data(buffer, n);
664 error = ssl_do_tx(stream);
667 ssl_clear_txbuf(sslv);
679 ssl_run(struct stream *stream)
681 struct ssl_stream *sslv = ssl_stream_cast(stream);
683 if (sslv->txbuf && ssl_do_tx(stream) != EAGAIN) {
684 ssl_clear_txbuf(sslv);
689 ssl_run_wait(struct stream *stream)
691 struct ssl_stream *sslv = ssl_stream_cast(stream);
693 if (sslv->tx_want != SSL_NOTHING) {
694 poll_fd_wait(sslv->fd, want_to_poll_events(sslv->tx_want));
699 ssl_wait(struct stream *stream, enum stream_wait_type wait)
701 struct ssl_stream *sslv = ssl_stream_cast(stream);
705 if (stream_connect(stream) != EAGAIN) {
706 poll_immediate_wake();
708 switch (sslv->state) {
709 case STATE_TCP_CONNECTING:
710 poll_fd_wait(sslv->fd, POLLOUT);
713 case STATE_SSL_CONNECTING:
714 /* ssl_connect() called SSL_accept() or SSL_connect(), which
715 * set up the status that we test here. */
716 poll_fd_wait(sslv->fd,
717 want_to_poll_events(SSL_want(sslv->ssl)));
727 if (sslv->rx_want != SSL_NOTHING) {
728 poll_fd_wait(sslv->fd, want_to_poll_events(sslv->rx_want));
730 poll_immediate_wake();
736 /* We have room in our tx queue. */
737 poll_immediate_wake();
739 /* stream_run_wait() will do the right thing; don't bother with
749 const struct stream_class ssl_stream_class = {
751 true, /* needs_probes */
753 ssl_close, /* close */
754 ssl_connect, /* connect */
758 ssl_run_wait, /* run_wait */
766 struct pstream pstream;
770 const struct pstream_class pssl_pstream_class;
772 static struct pssl_pstream *
773 pssl_pstream_cast(struct pstream *pstream)
775 pstream_assert_class(pstream, &pssl_pstream_class);
776 return CONTAINER_OF(pstream, struct pssl_pstream, pstream);
780 pssl_open(const char *name OVS_UNUSED, char *suffix, struct pstream **pstreamp,
783 struct pssl_pstream *pssl;
784 struct sockaddr_in sin;
785 char bound_name[128];
794 fd = inet_open_passive(SOCK_STREAM, suffix, OFP_OLD_PORT, &sin, dscp);
798 sprintf(bound_name, "pssl:%"PRIu16":"IP_FMT,
799 ntohs(sin.sin_port), IP_ARGS(sin.sin_addr.s_addr));
801 pssl = xmalloc(sizeof *pssl);
802 pstream_init(&pssl->pstream, &pssl_pstream_class, bound_name);
803 pstream_set_bound_port(&pssl->pstream, sin.sin_port);
805 *pstreamp = &pssl->pstream;
810 pssl_close(struct pstream *pstream)
812 struct pssl_pstream *pssl = pssl_pstream_cast(pstream);
818 pssl_accept(struct pstream *pstream, struct stream **new_streamp)
820 struct pssl_pstream *pssl = pssl_pstream_cast(pstream);
821 struct sockaddr_in sin;
822 socklen_t sin_len = sizeof sin;
827 new_fd = accept(pssl->fd, (struct sockaddr *) &sin, &sin_len);
830 if (error != EAGAIN) {
831 VLOG_DBG_RL(&rl, "accept: %s", ovs_strerror(error));
836 error = set_nonblocking(new_fd);
842 sprintf(name, "ssl:"IP_FMT, IP_ARGS(sin.sin_addr.s_addr));
843 if (sin.sin_port != htons(OFP_OLD_PORT)) {
844 sprintf(strchr(name, '\0'), ":%"PRIu16, ntohs(sin.sin_port));
846 return new_ssl_stream(name, new_fd, SERVER, STATE_SSL_CONNECTING,
851 pssl_wait(struct pstream *pstream)
853 struct pssl_pstream *pssl = pssl_pstream_cast(pstream);
854 poll_fd_wait(pssl->fd, POLLIN);
858 pssl_set_dscp(struct pstream *pstream, uint8_t dscp)
860 struct pssl_pstream *pssl = pssl_pstream_cast(pstream);
861 return set_dscp(pssl->fd, dscp);
864 const struct pstream_class pssl_pstream_class = {
875 * Returns true if OpenSSL error is WANT_READ or WANT_WRITE, indicating that
876 * OpenSSL is requesting that we call it back when the socket is ready for read
877 * or writing, respectively.
880 ssl_wants_io(int ssl_error)
882 return (ssl_error == SSL_ERROR_WANT_WRITE
883 || ssl_error == SSL_ERROR_WANT_READ);
889 static int init_status = -1;
890 if (init_status < 0) {
891 init_status = do_ssl_init();
892 ovs_assert(init_status >= 0);
903 SSL_load_error_strings();
905 if (!RAND_status()) {
906 /* We occasionally see OpenSSL fail to seed its random number generator
907 * in heavily loaded hypervisors. I suspect the following scenario:
909 * 1. OpenSSL calls read() to get 32 bytes from /dev/urandom.
910 * 2. The kernel generates 10 bytes of randomness and copies it out.
911 * 3. A signal arrives (perhaps SIGALRM).
912 * 4. The kernel interrupts the system call to service the signal.
913 * 5. Userspace gets 10 bytes of entropy.
914 * 6. OpenSSL doesn't read again to get the final 22 bytes. Therefore
915 * OpenSSL doesn't have enough entropy to consider itself
918 * The only part I'm not entirely sure about is #6, because the OpenSSL
919 * code is so hard to read. */
923 VLOG_WARN("OpenSSL random seeding failed, reseeding ourselves");
925 retval = get_entropy(seed, sizeof seed);
927 VLOG_ERR("failed to obtain entropy (%s)",
928 ovs_retval_to_string(retval));
929 return retval > 0 ? retval : ENOPROTOOPT;
932 RAND_seed(seed, sizeof seed);
935 /* New OpenSSL changed TLSv1_method() to return a "const" pointer, so the
936 * cast is needed to avoid a warning with those newer versions. */
937 method = CONST_CAST(SSL_METHOD *, TLSv1_method());
938 if (method == NULL) {
939 VLOG_ERR("TLSv1_method: %s", ERR_error_string(ERR_get_error(), NULL));
943 ctx = SSL_CTX_new(method);
945 VLOG_ERR("SSL_CTX_new: %s", ERR_error_string(ERR_get_error(), NULL));
948 SSL_CTX_set_options(ctx, SSL_OP_NO_SSLv2 | SSL_OP_NO_SSLv3);
949 SSL_CTX_set_tmp_dh_callback(ctx, tmp_dh_callback);
950 SSL_CTX_set_mode(ctx, SSL_MODE_ENABLE_PARTIAL_WRITE);
951 SSL_CTX_set_mode(ctx, SSL_MODE_ACCEPT_MOVING_WRITE_BUFFER);
952 SSL_CTX_set_verify(ctx, SSL_VERIFY_PEER | SSL_VERIFY_FAIL_IF_NO_PEER_CERT,
959 tmp_dh_callback(SSL *ssl OVS_UNUSED, int is_export OVS_UNUSED, int keylength)
964 DH *(*constructor)(void);
967 static struct dh dh_table[] = {
968 {1024, NULL, get_dh1024},
969 {2048, NULL, get_dh2048},
970 {4096, NULL, get_dh4096},
975 for (dh = dh_table; dh < &dh_table[ARRAY_SIZE(dh_table)]; dh++) {
976 if (dh->keylength == keylength) {
978 dh->dh = dh->constructor();
986 VLOG_ERR_RL(&rl, "no Diffie-Hellman parameters for key length %d",
991 /* Returns true if SSL is at least partially configured. */
993 stream_ssl_is_configured(void)
995 return private_key.file_name || certificate.file_name || ca_cert.file_name;
999 update_ssl_config(struct ssl_config_file *config, const char *file_name)
1001 struct timespec mtime;
1004 if (ssl_init() || !file_name) {
1008 /* If the file name hasn't changed and neither has the file contents, stop
1010 error = get_mtime(file_name, &mtime);
1011 if (error && error != ENOENT) {
1012 VLOG_ERR_RL(&rl, "%s: stat failed (%s)",
1013 file_name, ovs_strerror(error));
1015 if (config->file_name
1016 && !strcmp(config->file_name, file_name)
1017 && mtime.tv_sec == config->mtime.tv_sec
1018 && mtime.tv_nsec == config->mtime.tv_nsec) {
1022 /* Update 'config'. */
1023 config->mtime = mtime;
1024 if (file_name != config->file_name) {
1025 free(config->file_name);
1026 config->file_name = xstrdup(file_name);
1032 stream_ssl_set_private_key_file__(const char *file_name)
1034 if (SSL_CTX_use_PrivateKey_file(ctx, file_name, SSL_FILETYPE_PEM) == 1) {
1035 private_key.read = true;
1037 VLOG_ERR("SSL_use_PrivateKey_file: %s",
1038 ERR_error_string(ERR_get_error(), NULL));
1043 stream_ssl_set_private_key_file(const char *file_name)
1045 if (update_ssl_config(&private_key, file_name)) {
1046 stream_ssl_set_private_key_file__(file_name);
1051 stream_ssl_set_certificate_file__(const char *file_name)
1053 if (SSL_CTX_use_certificate_chain_file(ctx, file_name) == 1) {
1054 certificate.read = true;
1056 VLOG_ERR("SSL_use_certificate_file: %s",
1057 ERR_error_string(ERR_get_error(), NULL));
1062 stream_ssl_set_certificate_file(const char *file_name)
1064 if (update_ssl_config(&certificate, file_name)) {
1065 stream_ssl_set_certificate_file__(file_name);
1069 /* Sets the private key and certificate files in one operation. Use this
1070 * interface, instead of calling stream_ssl_set_private_key_file() and
1071 * stream_ssl_set_certificate_file() individually, in the main loop of a
1072 * long-running program whose key and certificate might change at runtime.
1074 * This is important because of OpenSSL's behavior. If an OpenSSL context
1075 * already has a certificate, and stream_ssl_set_private_key_file() is called
1076 * to install a new private key, OpenSSL will report an error because the new
1077 * private key does not match the old certificate. The other order, of setting
1078 * a new certificate, then setting a new private key, does work.
1080 * If this were the only problem, calling stream_ssl_set_certificate_file()
1081 * before stream_ssl_set_private_key_file() would fix it. But, if the private
1082 * key is changed before the certificate (e.g. someone "scp"s or "mv"s the new
1083 * private key in place before the certificate), then OpenSSL would reject that
1084 * change, and then the change of certificate would succeed, but there would be
1085 * no associated private key (because it had only changed once and therefore
1086 * there was no point in re-reading it).
1088 * This function avoids both problems by, whenever either the certificate or
1089 * the private key file changes, re-reading both of them, in the correct order.
1092 stream_ssl_set_key_and_cert(const char *private_key_file,
1093 const char *certificate_file)
1095 if (update_ssl_config(&private_key, private_key_file)
1096 || update_ssl_config(&certificate, certificate_file)) {
1097 stream_ssl_set_certificate_file__(certificate_file);
1098 stream_ssl_set_private_key_file__(private_key_file);
1102 /* Reads the X509 certificate or certificates in file 'file_name'. On success,
1103 * stores the address of the first element in an array of pointers to
1104 * certificates in '*certs' and the number of certificates in the array in
1105 * '*n_certs', and returns 0. On failure, stores a null pointer in '*certs', 0
1106 * in '*n_certs', and returns a positive errno value.
1108 * The caller is responsible for freeing '*certs'. */
1110 read_cert_file(const char *file_name, X509 ***certs, size_t *n_certs)
1113 size_t allocated_certs = 0;
1118 file = fopen(file_name, "r");
1120 VLOG_ERR("failed to open %s for reading: %s",
1121 file_name, ovs_strerror(errno));
1129 /* Read certificate from file. */
1130 certificate = PEM_read_X509(file, NULL, NULL, NULL);
1134 VLOG_ERR("PEM_read_X509 failed reading %s: %s",
1135 file_name, ERR_error_string(ERR_get_error(), NULL));
1136 for (i = 0; i < *n_certs; i++) {
1137 X509_free((*certs)[i]);
1145 /* Add certificate to array. */
1146 if (*n_certs >= allocated_certs) {
1147 *certs = x2nrealloc(*certs, &allocated_certs, sizeof **certs);
1149 (*certs)[(*n_certs)++] = certificate;
1151 /* Are there additional certificates in the file? */
1154 } while (isspace(c));
1165 /* Sets 'file_name' as the name of a file containing one or more X509
1166 * certificates to send to the peer. Typical use in OpenFlow is to send the CA
1167 * certificate to the peer, which enables a switch to pick up the controller's
1168 * CA certificate on its first connection. */
1170 stream_ssl_set_peer_ca_cert_file(const char *file_name)
1180 if (!read_cert_file(file_name, &certs, &n_certs)) {
1181 for (i = 0; i < n_certs; i++) {
1182 if (SSL_CTX_add_extra_chain_cert(ctx, certs[i]) != 1) {
1183 VLOG_ERR("SSL_CTX_add_extra_chain_cert: %s",
1184 ERR_error_string(ERR_get_error(), NULL));
1191 /* Logs fingerprint of CA certificate 'cert' obtained from 'file_name'. */
1193 log_ca_cert(const char *file_name, X509 *cert)
1195 unsigned char digest[EVP_MAX_MD_SIZE];
1196 unsigned int n_bytes;
1201 if (!X509_digest(cert, EVP_sha1(), digest, &n_bytes)) {
1202 ds_put_cstr(&fp, "<out of memory>");
1205 for (i = 0; i < n_bytes; i++) {
1207 ds_put_char(&fp, ':');
1209 ds_put_format(&fp, "%02x", digest[i]);
1212 subject = X509_NAME_oneline(X509_get_subject_name(cert), NULL, 0);
1213 VLOG_INFO("Trusting CA cert from %s (%s) (fingerprint %s)", file_name,
1214 subject ? subject : "<out of memory>", ds_cstr(&fp));
1215 OPENSSL_free(subject);
1220 stream_ssl_set_ca_cert_file__(const char *file_name,
1221 bool bootstrap, bool force)
1227 if (!update_ssl_config(&ca_cert, file_name) && !force) {
1231 if (!strcmp(file_name, "none")) {
1232 verify_peer_cert = false;
1233 VLOG_WARN("Peer certificate validation disabled "
1234 "(this is a security risk)");
1235 } else if (bootstrap && stat(file_name, &s) && errno == ENOENT) {
1236 bootstrap_ca_cert = true;
1237 } else if (!read_cert_file(file_name, &certs, &n_certs)) {
1240 /* Set up list of CAs that the server will accept from the client. */
1241 for (i = 0; i < n_certs; i++) {
1242 /* SSL_CTX_add_client_CA makes a copy of the relevant data. */
1243 if (SSL_CTX_add_client_CA(ctx, certs[i]) != 1) {
1244 VLOG_ERR("failed to add client certificate %"PRIuSIZE" from %s: %s",
1246 ERR_error_string(ERR_get_error(), NULL));
1248 log_ca_cert(file_name, certs[i]);
1250 X509_free(certs[i]);
1254 /* Set up CAs for OpenSSL to trust in verifying the peer's
1256 SSL_CTX_set_cert_store(ctx, X509_STORE_new());
1257 if (SSL_CTX_load_verify_locations(ctx, file_name, NULL) != 1) {
1258 VLOG_ERR("SSL_CTX_load_verify_locations: %s",
1259 ERR_error_string(ERR_get_error(), NULL));
1263 bootstrap_ca_cert = false;
1265 ca_cert.read = true;
1268 /* Sets 'file_name' as the name of the file from which to read the CA
1269 * certificate used to verify the peer within SSL connections. If 'bootstrap'
1270 * is false, the file must exist. If 'bootstrap' is false, then the file is
1271 * read if it is exists; if it does not, then it will be created from the CA
1272 * certificate received from the peer on the first SSL connection. */
1274 stream_ssl_set_ca_cert_file(const char *file_name, bool bootstrap)
1276 stream_ssl_set_ca_cert_file__(file_name, bootstrap, false);
1279 /* SSL protocol logging. */
1282 ssl_alert_level_to_string(uint8_t type)
1285 case 1: return "warning";
1286 case 2: return "fatal";
1287 default: return "<unknown>";
1292 ssl_alert_description_to_string(uint8_t type)
1295 case 0: return "close_notify";
1296 case 10: return "unexpected_message";
1297 case 20: return "bad_record_mac";
1298 case 21: return "decryption_failed";
1299 case 22: return "record_overflow";
1300 case 30: return "decompression_failure";
1301 case 40: return "handshake_failure";
1302 case 42: return "bad_certificate";
1303 case 43: return "unsupported_certificate";
1304 case 44: return "certificate_revoked";
1305 case 45: return "certificate_expired";
1306 case 46: return "certificate_unknown";
1307 case 47: return "illegal_parameter";
1308 case 48: return "unknown_ca";
1309 case 49: return "access_denied";
1310 case 50: return "decode_error";
1311 case 51: return "decrypt_error";
1312 case 60: return "export_restriction";
1313 case 70: return "protocol_version";
1314 case 71: return "insufficient_security";
1315 case 80: return "internal_error";
1316 case 90: return "user_canceled";
1317 case 100: return "no_renegotiation";
1318 default: return "<unknown>";
1323 ssl_handshake_type_to_string(uint8_t type)
1326 case 0: return "hello_request";
1327 case 1: return "client_hello";
1328 case 2: return "server_hello";
1329 case 11: return "certificate";
1330 case 12: return "server_key_exchange";
1331 case 13: return "certificate_request";
1332 case 14: return "server_hello_done";
1333 case 15: return "certificate_verify";
1334 case 16: return "client_key_exchange";
1335 case 20: return "finished";
1336 default: return "<unknown>";
1341 ssl_protocol_cb(int write_p, int version OVS_UNUSED, int content_type,
1342 const void *buf_, size_t len, SSL *ssl OVS_UNUSED, void *sslv_)
1344 const struct ssl_stream *sslv = sslv_;
1345 const uint8_t *buf = buf_;
1348 if (!VLOG_IS_DBG_ENABLED()) {
1353 if (content_type == 20) {
1354 ds_put_cstr(&details, "change_cipher_spec");
1355 } else if (content_type == 21) {
1356 ds_put_format(&details, "alert: %s, %s",
1357 ssl_alert_level_to_string(buf[0]),
1358 ssl_alert_description_to_string(buf[1]));
1359 } else if (content_type == 22) {
1360 ds_put_format(&details, "handshake: %s",
1361 ssl_handshake_type_to_string(buf[0]));
1363 ds_put_format(&details, "type %d", content_type);
1366 VLOG_DBG("%s%u%s%s %s (%"PRIuSIZE" bytes)",
1367 sslv->type == CLIENT ? "client" : "server",
1368 sslv->session_nr, write_p ? "-->" : "<--",
1369 stream_get_name(&sslv->stream), ds_cstr(&details), len);
1371 ds_destroy(&details);