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, const struct sockaddr_in *remote,
208 struct stream **streamp)
210 struct sockaddr_in local;
211 socklen_t local_len = sizeof local;
212 struct ssl_stream *sslv;
217 /* Check for all the needful configuration. */
219 if (!private_key.read) {
220 VLOG_ERR("Private key must be configured to use SSL");
221 retval = ENOPROTOOPT;
223 if (!certificate.read) {
224 VLOG_ERR("Certificate must be configured to use SSL");
225 retval = ENOPROTOOPT;
227 if (!ca_cert.read && verify_peer_cert && !bootstrap_ca_cert) {
228 VLOG_ERR("CA certificate must be configured to use SSL");
229 retval = ENOPROTOOPT;
231 if (!retval && !SSL_CTX_check_private_key(ctx)) {
232 VLOG_ERR("Private key does not match certificate public key: %s",
233 ERR_error_string(ERR_get_error(), NULL));
234 retval = ENOPROTOOPT;
240 /* Get the local IP and port information */
241 retval = getsockname(fd, (struct sockaddr *) &local, &local_len);
243 memset(&local, 0, sizeof local);
247 retval = setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &on, sizeof on);
249 VLOG_ERR("%s: setsockopt(TCP_NODELAY): %s", name, strerror(errno));
254 /* Create and configure OpenSSL stream. */
257 VLOG_ERR("SSL_new: %s", ERR_error_string(ERR_get_error(), NULL));
258 retval = ENOPROTOOPT;
261 if (SSL_set_fd(ssl, fd) == 0) {
262 VLOG_ERR("SSL_set_fd: %s", ERR_error_string(ERR_get_error(), NULL));
263 retval = ENOPROTOOPT;
266 if (!verify_peer_cert || (bootstrap_ca_cert && type == CLIENT)) {
267 SSL_set_verify(ssl, SSL_VERIFY_NONE, NULL);
270 /* Create and return the ssl_stream. */
271 sslv = xmalloc(sizeof *sslv);
272 stream_init(&sslv->stream, &ssl_stream_class, EAGAIN, name);
273 stream_set_remote_ip(&sslv->stream, remote->sin_addr.s_addr);
274 stream_set_remote_port(&sslv->stream, remote->sin_port);
275 stream_set_local_ip(&sslv->stream, local.sin_addr.s_addr);
276 stream_set_local_port(&sslv->stream, local.sin_port);
282 sslv->rx_want = sslv->tx_want = SSL_NOTHING;
283 sslv->session_nr = next_session_nr++;
286 if (VLOG_IS_DBG_ENABLED()) {
287 SSL_set_msg_callback(ssl, ssl_protocol_cb);
288 SSL_set_msg_callback_arg(ssl, sslv);
291 *streamp = &sslv->stream;
302 static struct ssl_stream *
303 ssl_stream_cast(struct stream *stream)
305 stream_assert_class(stream, &ssl_stream_class);
306 return CONTAINER_OF(stream, struct ssl_stream, stream);
310 ssl_open(const char *name, char *suffix, struct stream **streamp, uint8_t dscp)
312 struct sockaddr_in sin;
320 error = inet_open_active(SOCK_STREAM, suffix, OFP_SSL_PORT, &sin, &fd,
323 int state = error ? STATE_TCP_CONNECTING : STATE_SSL_CONNECTING;
324 return new_ssl_stream(name, fd, CLIENT, state, &sin, streamp);
326 VLOG_ERR("%s: connect: %s", name, strerror(error));
332 do_ca_cert_bootstrap(struct stream *stream)
334 struct ssl_stream *sslv = ssl_stream_cast(stream);
335 STACK_OF(X509) *chain;
341 chain = SSL_get_peer_cert_chain(sslv->ssl);
342 if (!chain || !sk_X509_num(chain)) {
343 VLOG_ERR("could not bootstrap CA cert: no certificate presented by "
347 cert = sk_X509_value(chain, sk_X509_num(chain) - 1);
349 /* Check that 'cert' is self-signed. Otherwise it is not a CA
350 * certificate and we should not attempt to use it as one. */
351 error = X509_check_issued(cert, cert);
353 VLOG_ERR("could not bootstrap CA cert: obtained certificate is "
354 "not self-signed (%s)",
355 X509_verify_cert_error_string(error));
356 if (sk_X509_num(chain) < 2) {
357 VLOG_ERR("only one certificate was received, so probably the peer "
358 "is not configured to send its CA certificate");
363 fd = open(ca_cert.file_name, O_CREAT | O_EXCL | O_WRONLY, 0444);
365 if (errno == EEXIST) {
366 VLOG_INFO_RL(&rl, "reading CA cert %s created by another process",
368 stream_ssl_set_ca_cert_file__(ca_cert.file_name, true, true);
371 VLOG_ERR("could not bootstrap CA cert: creating %s failed: %s",
372 ca_cert.file_name, strerror(errno));
377 file = fdopen(fd, "w");
380 VLOG_ERR("could not bootstrap CA cert: fdopen failed: %s",
382 unlink(ca_cert.file_name);
386 if (!PEM_write_X509(file, cert)) {
387 VLOG_ERR("could not bootstrap CA cert: PEM_write_X509 to %s failed: "
388 "%s", ca_cert.file_name,
389 ERR_error_string(ERR_get_error(), NULL));
391 unlink(ca_cert.file_name);
397 VLOG_ERR("could not bootstrap CA cert: writing %s failed: %s",
398 ca_cert.file_name, strerror(error));
399 unlink(ca_cert.file_name);
403 VLOG_INFO("successfully bootstrapped CA cert to %s", ca_cert.file_name);
404 log_ca_cert(ca_cert.file_name, cert);
405 bootstrap_ca_cert = false;
408 /* SSL_CTX_add_client_CA makes a copy of cert's relevant data. */
409 SSL_CTX_add_client_CA(ctx, cert);
411 /* SSL_CTX_use_certificate() takes ownership of the certificate passed in.
412 * 'cert' is owned by sslv->ssl, so we need to duplicate it. */
413 cert = X509_dup(cert);
417 SSL_CTX_set_cert_store(ctx, X509_STORE_new());
418 if (SSL_CTX_load_verify_locations(ctx, ca_cert.file_name, NULL) != 1) {
419 VLOG_ERR("SSL_CTX_load_verify_locations: %s",
420 ERR_error_string(ERR_get_error(), NULL));
423 VLOG_INFO("killing successful connection to retry using CA cert");
428 ssl_connect(struct stream *stream)
430 struct ssl_stream *sslv = ssl_stream_cast(stream);
433 switch (sslv->state) {
434 case STATE_TCP_CONNECTING:
435 retval = check_connection_completion(sslv->fd);
439 sslv->state = STATE_SSL_CONNECTING;
442 case STATE_SSL_CONNECTING:
443 /* Capture the first few bytes of received data so that we can guess
444 * what kind of funny data we've been sent if SSL negotiation fails. */
445 if (sslv->n_head <= 0) {
446 sslv->n_head = recv(sslv->fd, sslv->head, sizeof sslv->head,
450 retval = (sslv->type == CLIENT
451 ? SSL_connect(sslv->ssl) : SSL_accept(sslv->ssl));
453 int error = SSL_get_error(sslv->ssl, retval);
454 if (retval < 0 && ssl_wants_io(error)) {
459 interpret_ssl_error((sslv->type == CLIENT ? "SSL_connect"
460 : "SSL_accept"), retval, error, &unused);
461 shutdown(sslv->fd, SHUT_RDWR);
462 stream_report_content(sslv->head, sslv->n_head, STREAM_SSL,
463 THIS_MODULE, stream_get_name(stream));
466 } else if (bootstrap_ca_cert) {
467 return do_ca_cert_bootstrap(stream);
468 } else if (verify_peer_cert
469 && ((SSL_get_verify_mode(sslv->ssl)
470 & (SSL_VERIFY_NONE | SSL_VERIFY_PEER))
471 != SSL_VERIFY_PEER)) {
472 /* Two or more SSL connections completed at the same time while we
473 * were in bootstrap mode. Only one of these can finish the
474 * bootstrap successfully. The other one(s) must be rejected
475 * because they were not verified against the bootstrapped CA
476 * certificate. (Alternatively we could verify them against the CA
477 * certificate, but that's more trouble than it's worth. These
478 * connections will succeed the next time they retry, assuming that
479 * they have a certificate against the correct CA.) */
480 VLOG_INFO("rejecting SSL connection during bootstrap race window");
491 ssl_close(struct stream *stream)
493 struct ssl_stream *sslv = ssl_stream_cast(stream);
494 ssl_clear_txbuf(sslv);
496 /* Attempt clean shutdown of the SSL connection. This will work most of
497 * the time, as long as the kernel send buffer has some free space and the
498 * SSL connection isn't renegotiating, etc. That has to be good enough,
499 * since we don't have any way to continue the close operation in the
501 SSL_shutdown(sslv->ssl);
503 /* SSL_shutdown() might have signaled an error, in which case we need to
504 * flush it out of the OpenSSL error queue or the next OpenSSL operation
505 * will falsely signal an error. */
514 interpret_queued_ssl_error(const char *function)
516 int queued_error = ERR_get_error();
517 if (queued_error != 0) {
518 VLOG_WARN_RL(&rl, "%s: %s",
519 function, ERR_error_string(queued_error, NULL));
521 VLOG_ERR_RL(&rl, "%s: SSL_ERROR_SSL without queued error", function);
526 interpret_ssl_error(const char *function, int ret, int error,
533 VLOG_ERR_RL(&rl, "%s: unexpected SSL_ERROR_NONE", function);
536 case SSL_ERROR_ZERO_RETURN:
537 VLOG_ERR_RL(&rl, "%s: unexpected SSL_ERROR_ZERO_RETURN", function);
540 case SSL_ERROR_WANT_READ:
544 case SSL_ERROR_WANT_WRITE:
548 case SSL_ERROR_WANT_CONNECT:
549 VLOG_ERR_RL(&rl, "%s: unexpected SSL_ERROR_WANT_CONNECT", function);
552 case SSL_ERROR_WANT_ACCEPT:
553 VLOG_ERR_RL(&rl, "%s: unexpected SSL_ERROR_WANT_ACCEPT", function);
556 case SSL_ERROR_WANT_X509_LOOKUP:
557 VLOG_ERR_RL(&rl, "%s: unexpected SSL_ERROR_WANT_X509_LOOKUP",
561 case SSL_ERROR_SYSCALL: {
562 int queued_error = ERR_get_error();
563 if (queued_error == 0) {
566 VLOG_WARN_RL(&rl, "%s: system error (%s)",
567 function, strerror(status));
570 VLOG_WARN_RL(&rl, "%s: unexpected SSL connection close",
575 VLOG_WARN_RL(&rl, "%s: %s",
576 function, ERR_error_string(queued_error, NULL));
582 interpret_queued_ssl_error(function);
586 VLOG_ERR_RL(&rl, "%s: bad SSL error code %d", function, error);
593 ssl_recv(struct stream *stream, void *buffer, size_t n)
595 struct ssl_stream *sslv = ssl_stream_cast(stream);
599 /* Behavior of zero-byte SSL_read is poorly defined. */
602 old_state = SSL_get_state(sslv->ssl);
603 ret = SSL_read(sslv->ssl, buffer, n);
604 if (old_state != SSL_get_state(sslv->ssl)) {
605 sslv->tx_want = SSL_NOTHING;
607 sslv->rx_want = SSL_NOTHING;
612 int error = SSL_get_error(sslv->ssl, ret);
613 if (error == SSL_ERROR_ZERO_RETURN) {
616 return -interpret_ssl_error("SSL_read", ret, error,
623 ssl_clear_txbuf(struct ssl_stream *sslv)
625 ofpbuf_delete(sslv->txbuf);
630 ssl_do_tx(struct stream *stream)
632 struct ssl_stream *sslv = ssl_stream_cast(stream);
635 int old_state = SSL_get_state(sslv->ssl);
636 int ret = SSL_write(sslv->ssl, sslv->txbuf->data, sslv->txbuf->size);
637 if (old_state != SSL_get_state(sslv->ssl)) {
638 sslv->rx_want = SSL_NOTHING;
640 sslv->tx_want = SSL_NOTHING;
642 ofpbuf_pull(sslv->txbuf, ret);
643 if (sslv->txbuf->size == 0) {
647 int ssl_error = SSL_get_error(sslv->ssl, ret);
648 if (ssl_error == SSL_ERROR_ZERO_RETURN) {
649 VLOG_WARN_RL(&rl, "SSL_write: connection closed");
652 return interpret_ssl_error("SSL_write", ret, ssl_error,
660 ssl_send(struct stream *stream, const void *buffer, size_t n)
662 struct ssl_stream *sslv = ssl_stream_cast(stream);
669 sslv->txbuf = ofpbuf_clone_data(buffer, n);
670 error = ssl_do_tx(stream);
673 ssl_clear_txbuf(sslv);
685 ssl_run(struct stream *stream)
687 struct ssl_stream *sslv = ssl_stream_cast(stream);
689 if (sslv->txbuf && ssl_do_tx(stream) != EAGAIN) {
690 ssl_clear_txbuf(sslv);
695 ssl_run_wait(struct stream *stream)
697 struct ssl_stream *sslv = ssl_stream_cast(stream);
699 if (sslv->tx_want != SSL_NOTHING) {
700 poll_fd_wait(sslv->fd, want_to_poll_events(sslv->tx_want));
705 ssl_wait(struct stream *stream, enum stream_wait_type wait)
707 struct ssl_stream *sslv = ssl_stream_cast(stream);
711 if (stream_connect(stream) != EAGAIN) {
712 poll_immediate_wake();
714 switch (sslv->state) {
715 case STATE_TCP_CONNECTING:
716 poll_fd_wait(sslv->fd, POLLOUT);
719 case STATE_SSL_CONNECTING:
720 /* ssl_connect() called SSL_accept() or SSL_connect(), which
721 * set up the status that we test here. */
722 poll_fd_wait(sslv->fd,
723 want_to_poll_events(SSL_want(sslv->ssl)));
733 if (sslv->rx_want != SSL_NOTHING) {
734 poll_fd_wait(sslv->fd, want_to_poll_events(sslv->rx_want));
736 poll_immediate_wake();
742 /* We have room in our tx queue. */
743 poll_immediate_wake();
745 /* stream_run_wait() will do the right thing; don't bother with
755 const struct stream_class ssl_stream_class = {
757 true, /* needs_probes */
759 ssl_close, /* close */
760 ssl_connect, /* connect */
764 ssl_run_wait, /* run_wait */
772 struct pstream pstream;
776 const struct pstream_class pssl_pstream_class;
778 static struct pssl_pstream *
779 pssl_pstream_cast(struct pstream *pstream)
781 pstream_assert_class(pstream, &pssl_pstream_class);
782 return CONTAINER_OF(pstream, struct pssl_pstream, pstream);
786 pssl_open(const char *name OVS_UNUSED, char *suffix, struct pstream **pstreamp,
789 struct pssl_pstream *pssl;
790 struct sockaddr_in sin;
791 char bound_name[128];
800 fd = inet_open_passive(SOCK_STREAM, suffix, OFP_SSL_PORT, &sin, dscp);
804 sprintf(bound_name, "pssl:%"PRIu16":"IP_FMT,
805 ntohs(sin.sin_port), IP_ARGS(sin.sin_addr.s_addr));
807 pssl = xmalloc(sizeof *pssl);
808 pstream_init(&pssl->pstream, &pssl_pstream_class, bound_name);
809 pstream_set_bound_port(&pssl->pstream, sin.sin_port);
811 *pstreamp = &pssl->pstream;
816 pssl_close(struct pstream *pstream)
818 struct pssl_pstream *pssl = pssl_pstream_cast(pstream);
824 pssl_accept(struct pstream *pstream, struct stream **new_streamp)
826 struct pssl_pstream *pssl = pssl_pstream_cast(pstream);
827 struct sockaddr_in sin;
828 socklen_t sin_len = sizeof sin;
833 new_fd = accept(pssl->fd, (struct sockaddr *) &sin, &sin_len);
836 if (error != EAGAIN) {
837 VLOG_DBG_RL(&rl, "accept: %s", strerror(error));
842 error = set_nonblocking(new_fd);
848 sprintf(name, "ssl:"IP_FMT, IP_ARGS(sin.sin_addr.s_addr));
849 if (sin.sin_port != htons(OFP_SSL_PORT)) {
850 sprintf(strchr(name, '\0'), ":%"PRIu16, ntohs(sin.sin_port));
852 return new_ssl_stream(name, new_fd, SERVER, STATE_SSL_CONNECTING, &sin,
857 pssl_wait(struct pstream *pstream)
859 struct pssl_pstream *pssl = pssl_pstream_cast(pstream);
860 poll_fd_wait(pssl->fd, POLLIN);
864 pssl_set_dscp(struct pstream *pstream, uint8_t dscp)
866 struct pssl_pstream *pssl = pssl_pstream_cast(pstream);
867 return set_dscp(pssl->fd, dscp);
870 const struct pstream_class pssl_pstream_class = {
881 * Returns true if OpenSSL error is WANT_READ or WANT_WRITE, indicating that
882 * OpenSSL is requesting that we call it back when the socket is ready for read
883 * or writing, respectively.
886 ssl_wants_io(int ssl_error)
888 return (ssl_error == SSL_ERROR_WANT_WRITE
889 || ssl_error == SSL_ERROR_WANT_READ);
895 static int init_status = -1;
896 if (init_status < 0) {
897 init_status = do_ssl_init();
898 ovs_assert(init_status >= 0);
909 SSL_load_error_strings();
911 if (!RAND_status()) {
912 /* We occasionally see OpenSSL fail to seed its random number generator
913 * in heavily loaded hypervisors. I suspect the following scenario:
915 * 1. OpenSSL calls read() to get 32 bytes from /dev/urandom.
916 * 2. The kernel generates 10 bytes of randomness and copies it out.
917 * 3. A signal arrives (perhaps SIGALRM).
918 * 4. The kernel interrupts the system call to service the signal.
919 * 5. Userspace gets 10 bytes of entropy.
920 * 6. OpenSSL doesn't read again to get the final 22 bytes. Therefore
921 * OpenSSL doesn't have enough entropy to consider itself
924 * The only part I'm not entirely sure about is #6, because the OpenSSL
925 * code is so hard to read. */
929 VLOG_WARN("OpenSSL random seeding failed, reseeding ourselves");
931 retval = get_entropy(seed, sizeof seed);
933 VLOG_ERR("failed to obtain entropy (%s)",
934 ovs_retval_to_string(retval));
935 return retval > 0 ? retval : ENOPROTOOPT;
938 RAND_seed(seed, sizeof seed);
941 /* New OpenSSL changed TLSv1_method() to return a "const" pointer, so the
942 * cast is needed to avoid a warning with those newer versions. */
943 method = CONST_CAST(SSL_METHOD *, TLSv1_method());
944 if (method == NULL) {
945 VLOG_ERR("TLSv1_method: %s", ERR_error_string(ERR_get_error(), NULL));
949 ctx = SSL_CTX_new(method);
951 VLOG_ERR("SSL_CTX_new: %s", ERR_error_string(ERR_get_error(), NULL));
954 SSL_CTX_set_options(ctx, SSL_OP_NO_SSLv2 | SSL_OP_NO_SSLv3);
955 SSL_CTX_set_tmp_dh_callback(ctx, tmp_dh_callback);
956 SSL_CTX_set_mode(ctx, SSL_MODE_ENABLE_PARTIAL_WRITE);
957 SSL_CTX_set_mode(ctx, SSL_MODE_ACCEPT_MOVING_WRITE_BUFFER);
958 SSL_CTX_set_verify(ctx, SSL_VERIFY_PEER | SSL_VERIFY_FAIL_IF_NO_PEER_CERT,
965 tmp_dh_callback(SSL *ssl OVS_UNUSED, int is_export OVS_UNUSED, int keylength)
970 DH *(*constructor)(void);
973 static struct dh dh_table[] = {
974 {1024, NULL, get_dh1024},
975 {2048, NULL, get_dh2048},
976 {4096, NULL, get_dh4096},
981 for (dh = dh_table; dh < &dh_table[ARRAY_SIZE(dh_table)]; dh++) {
982 if (dh->keylength == keylength) {
984 dh->dh = dh->constructor();
992 VLOG_ERR_RL(&rl, "no Diffie-Hellman parameters for key length %d",
997 /* Returns true if SSL is at least partially configured. */
999 stream_ssl_is_configured(void)
1001 return private_key.file_name || certificate.file_name || ca_cert.file_name;
1005 update_ssl_config(struct ssl_config_file *config, const char *file_name)
1007 struct timespec mtime;
1010 if (ssl_init() || !file_name) {
1014 /* If the file name hasn't changed and neither has the file contents, stop
1016 error = get_mtime(file_name, &mtime);
1017 if (error && error != ENOENT) {
1018 VLOG_ERR_RL(&rl, "%s: stat failed (%s)", file_name, strerror(error));
1020 if (config->file_name
1021 && !strcmp(config->file_name, file_name)
1022 && mtime.tv_sec == config->mtime.tv_sec
1023 && mtime.tv_nsec == config->mtime.tv_nsec) {
1027 /* Update 'config'. */
1028 config->mtime = mtime;
1029 if (file_name != config->file_name) {
1030 free(config->file_name);
1031 config->file_name = xstrdup(file_name);
1037 stream_ssl_set_private_key_file__(const char *file_name)
1039 if (SSL_CTX_use_PrivateKey_file(ctx, file_name, SSL_FILETYPE_PEM) == 1) {
1040 private_key.read = true;
1042 VLOG_ERR("SSL_use_PrivateKey_file: %s",
1043 ERR_error_string(ERR_get_error(), NULL));
1048 stream_ssl_set_private_key_file(const char *file_name)
1050 if (update_ssl_config(&private_key, file_name)) {
1051 stream_ssl_set_private_key_file__(file_name);
1056 stream_ssl_set_certificate_file__(const char *file_name)
1058 if (SSL_CTX_use_certificate_chain_file(ctx, file_name) == 1) {
1059 certificate.read = true;
1061 VLOG_ERR("SSL_use_certificate_file: %s",
1062 ERR_error_string(ERR_get_error(), NULL));
1067 stream_ssl_set_certificate_file(const char *file_name)
1069 if (update_ssl_config(&certificate, file_name)) {
1070 stream_ssl_set_certificate_file__(file_name);
1074 /* Sets the private key and certificate files in one operation. Use this
1075 * interface, instead of calling stream_ssl_set_private_key_file() and
1076 * stream_ssl_set_certificate_file() individually, in the main loop of a
1077 * long-running program whose key and certificate might change at runtime.
1079 * This is important because of OpenSSL's behavior. If an OpenSSL context
1080 * already has a certificate, and stream_ssl_set_private_key_file() is called
1081 * to install a new private key, OpenSSL will report an error because the new
1082 * private key does not match the old certificate. The other order, of setting
1083 * a new certificate, then setting a new private key, does work.
1085 * If this were the only problem, calling stream_ssl_set_certificate_file()
1086 * before stream_ssl_set_private_key_file() would fix it. But, if the private
1087 * key is changed before the certificate (e.g. someone "scp"s or "mv"s the new
1088 * private key in place before the certificate), then OpenSSL would reject that
1089 * change, and then the change of certificate would succeed, but there would be
1090 * no associated private key (because it had only changed once and therefore
1091 * there was no point in re-reading it).
1093 * This function avoids both problems by, whenever either the certificate or
1094 * the private key file changes, re-reading both of them, in the correct order.
1097 stream_ssl_set_key_and_cert(const char *private_key_file,
1098 const char *certificate_file)
1100 if (update_ssl_config(&private_key, private_key_file)
1101 || update_ssl_config(&certificate, certificate_file)) {
1102 stream_ssl_set_certificate_file__(certificate_file);
1103 stream_ssl_set_private_key_file__(private_key_file);
1107 /* Reads the X509 certificate or certificates in file 'file_name'. On success,
1108 * stores the address of the first element in an array of pointers to
1109 * certificates in '*certs' and the number of certificates in the array in
1110 * '*n_certs', and returns 0. On failure, stores a null pointer in '*certs', 0
1111 * in '*n_certs', and returns a positive errno value.
1113 * The caller is responsible for freeing '*certs'. */
1115 read_cert_file(const char *file_name, X509 ***certs, size_t *n_certs)
1118 size_t allocated_certs = 0;
1123 file = fopen(file_name, "r");
1125 VLOG_ERR("failed to open %s for reading: %s",
1126 file_name, strerror(errno));
1134 /* Read certificate from file. */
1135 certificate = PEM_read_X509(file, NULL, NULL, NULL);
1139 VLOG_ERR("PEM_read_X509 failed reading %s: %s",
1140 file_name, ERR_error_string(ERR_get_error(), NULL));
1141 for (i = 0; i < *n_certs; i++) {
1142 X509_free((*certs)[i]);
1150 /* Add certificate to array. */
1151 if (*n_certs >= allocated_certs) {
1152 *certs = x2nrealloc(*certs, &allocated_certs, sizeof **certs);
1154 (*certs)[(*n_certs)++] = certificate;
1156 /* Are there additional certificates in the file? */
1159 } while (isspace(c));
1170 /* Sets 'file_name' as the name of a file containing one or more X509
1171 * certificates to send to the peer. Typical use in OpenFlow is to send the CA
1172 * certificate to the peer, which enables a switch to pick up the controller's
1173 * CA certificate on its first connection. */
1175 stream_ssl_set_peer_ca_cert_file(const char *file_name)
1185 if (!read_cert_file(file_name, &certs, &n_certs)) {
1186 for (i = 0; i < n_certs; i++) {
1187 if (SSL_CTX_add_extra_chain_cert(ctx, certs[i]) != 1) {
1188 VLOG_ERR("SSL_CTX_add_extra_chain_cert: %s",
1189 ERR_error_string(ERR_get_error(), NULL));
1196 /* Logs fingerprint of CA certificate 'cert' obtained from 'file_name'. */
1198 log_ca_cert(const char *file_name, X509 *cert)
1200 unsigned char digest[EVP_MAX_MD_SIZE];
1201 unsigned int n_bytes;
1206 if (!X509_digest(cert, EVP_sha1(), digest, &n_bytes)) {
1207 ds_put_cstr(&fp, "<out of memory>");
1210 for (i = 0; i < n_bytes; i++) {
1212 ds_put_char(&fp, ':');
1214 ds_put_format(&fp, "%02hhx", digest[i]);
1217 subject = X509_NAME_oneline(X509_get_subject_name(cert), NULL, 0);
1218 VLOG_INFO("Trusting CA cert from %s (%s) (fingerprint %s)", file_name,
1219 subject ? subject : "<out of memory>", ds_cstr(&fp));
1220 OPENSSL_free(subject);
1225 stream_ssl_set_ca_cert_file__(const char *file_name,
1226 bool bootstrap, bool force)
1232 if (!update_ssl_config(&ca_cert, file_name) && !force) {
1236 if (!strcmp(file_name, "none")) {
1237 verify_peer_cert = false;
1238 VLOG_WARN("Peer certificate validation disabled "
1239 "(this is a security risk)");
1240 } else if (bootstrap && stat(file_name, &s) && errno == ENOENT) {
1241 bootstrap_ca_cert = true;
1242 } else if (!read_cert_file(file_name, &certs, &n_certs)) {
1245 /* Set up list of CAs that the server will accept from the client. */
1246 for (i = 0; i < n_certs; i++) {
1247 /* SSL_CTX_add_client_CA makes a copy of the relevant data. */
1248 if (SSL_CTX_add_client_CA(ctx, certs[i]) != 1) {
1249 VLOG_ERR("failed to add client certificate %zu from %s: %s",
1251 ERR_error_string(ERR_get_error(), NULL));
1253 log_ca_cert(file_name, certs[i]);
1255 X509_free(certs[i]);
1259 /* Set up CAs for OpenSSL to trust in verifying the peer's
1261 SSL_CTX_set_cert_store(ctx, X509_STORE_new());
1262 if (SSL_CTX_load_verify_locations(ctx, file_name, NULL) != 1) {
1263 VLOG_ERR("SSL_CTX_load_verify_locations: %s",
1264 ERR_error_string(ERR_get_error(), NULL));
1268 bootstrap_ca_cert = false;
1270 ca_cert.read = true;
1273 /* Sets 'file_name' as the name of the file from which to read the CA
1274 * certificate used to verify the peer within SSL connections. If 'bootstrap'
1275 * is false, the file must exist. If 'bootstrap' is false, then the file is
1276 * read if it is exists; if it does not, then it will be created from the CA
1277 * certificate received from the peer on the first SSL connection. */
1279 stream_ssl_set_ca_cert_file(const char *file_name, bool bootstrap)
1281 stream_ssl_set_ca_cert_file__(file_name, bootstrap, false);
1284 /* SSL protocol logging. */
1287 ssl_alert_level_to_string(uint8_t type)
1290 case 1: return "warning";
1291 case 2: return "fatal";
1292 default: return "<unknown>";
1297 ssl_alert_description_to_string(uint8_t type)
1300 case 0: return "close_notify";
1301 case 10: return "unexpected_message";
1302 case 20: return "bad_record_mac";
1303 case 21: return "decryption_failed";
1304 case 22: return "record_overflow";
1305 case 30: return "decompression_failure";
1306 case 40: return "handshake_failure";
1307 case 42: return "bad_certificate";
1308 case 43: return "unsupported_certificate";
1309 case 44: return "certificate_revoked";
1310 case 45: return "certificate_expired";
1311 case 46: return "certificate_unknown";
1312 case 47: return "illegal_parameter";
1313 case 48: return "unknown_ca";
1314 case 49: return "access_denied";
1315 case 50: return "decode_error";
1316 case 51: return "decrypt_error";
1317 case 60: return "export_restriction";
1318 case 70: return "protocol_version";
1319 case 71: return "insufficient_security";
1320 case 80: return "internal_error";
1321 case 90: return "user_canceled";
1322 case 100: return "no_renegotiation";
1323 default: return "<unknown>";
1328 ssl_handshake_type_to_string(uint8_t type)
1331 case 0: return "hello_request";
1332 case 1: return "client_hello";
1333 case 2: return "server_hello";
1334 case 11: return "certificate";
1335 case 12: return "server_key_exchange";
1336 case 13: return "certificate_request";
1337 case 14: return "server_hello_done";
1338 case 15: return "certificate_verify";
1339 case 16: return "client_key_exchange";
1340 case 20: return "finished";
1341 default: return "<unknown>";
1346 ssl_protocol_cb(int write_p, int version OVS_UNUSED, int content_type,
1347 const void *buf_, size_t len, SSL *ssl OVS_UNUSED, void *sslv_)
1349 const struct ssl_stream *sslv = sslv_;
1350 const uint8_t *buf = buf_;
1353 if (!VLOG_IS_DBG_ENABLED()) {
1358 if (content_type == 20) {
1359 ds_put_cstr(&details, "change_cipher_spec");
1360 } else if (content_type == 21) {
1361 ds_put_format(&details, "alert: %s, %s",
1362 ssl_alert_level_to_string(buf[0]),
1363 ssl_alert_description_to_string(buf[1]));
1364 } else if (content_type == 22) {
1365 ds_put_format(&details, "handshake: %s",
1366 ssl_handshake_type_to_string(buf[0]));
1368 ds_put_format(&details, "type %d", content_type);
1371 VLOG_DBG("%s%u%s%s %s (%zu bytes)",
1372 sslv->type == CLIENT ? "client" : "server",
1373 sslv->session_nr, write_p ? "-->" : "<--",
1374 stream_get_name(&sslv->stream), ds_cstr(&details), len);
1376 ds_destroy(&details);