2 * Copyright (c) 2008, 2009, 2010, 2011, 2012, 2013, 2014 Nicira, Inc.
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at:
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
18 #include "stream-ssl.h"
24 #include <sys/types.h>
25 #include <sys/socket.h>
26 #include <netinet/tcp.h>
27 #include <openssl/err.h>
28 #include <openssl/rand.h>
29 #include <openssl/ssl.h>
30 #include <openssl/x509v3.h>
36 #include "dynamic-string.h"
39 #include "openflow/openflow.h"
41 #include "poll-loop.h"
43 #include "socket-util.h"
45 #include "stream-provider.h"
51 /* Ref: https://www.openssl.org/support/faq.html#PROG2
52 * Your application must link against the same version of the Win32 C-Runtime
53 * against which your openssl libraries were linked. The default version for
54 * OpenSSL is /MD - "Multithreaded DLL". If we compile Open vSwitch with
55 * something other than /MD, instead of re-compiling OpenSSL
56 * toolkit, openssl/applink.c can be #included. Also, it is important
57 * to add CRYPTO_malloc_init prior first call to OpenSSL.
59 * XXX: The behavior of the following #include when Open vSwitch is
60 * compiled with /MD is not tested. */
61 #include <openssl/applink.c>
62 #define SHUT_RDWR SD_BOTH
65 VLOG_DEFINE_THIS_MODULE(stream_ssl);
83 enum session_type type;
87 unsigned int session_nr;
89 /* rx_want and tx_want record the result of the last call to SSL_read()
90 * and SSL_write(), respectively:
92 * - If the call reported that data needed to be read from the file
93 * descriptor, the corresponding member is set to SSL_READING.
95 * - If the call reported that data needed to be written to the file
96 * descriptor, the corresponding member is set to SSL_WRITING.
98 * - Otherwise, the member is set to SSL_NOTHING, indicating that the
99 * call completed successfully (or with an error) and that there is no
102 * These are needed because there is no way to ask OpenSSL what a data read
103 * or write would require without giving it a buffer to receive into or
104 * data to send, respectively. (Note that the SSL_want() status is
105 * overwritten by each SSL_read() or SSL_write() call, so we can't rely on
108 * A single call to SSL_read() or SSL_write() can perform both reading
109 * and writing and thus invalidate not one of these values but actually
110 * both. Consider this situation, for example:
112 * - SSL_write() blocks on a read, so tx_want gets SSL_READING.
114 * - SSL_read() laters succeeds reading from 'fd' and clears out the
115 * whole receive buffer, so rx_want gets SSL_READING.
117 * - Client calls stream_wait(STREAM_RECV) and stream_wait(STREAM_SEND)
120 * - Now we're stuck blocking until the peer sends us data, even though
121 * SSL_write() could now succeed, which could easily be a deadlock
124 * On the other hand, we can't reset both tx_want and rx_want on every call
125 * to SSL_read() or SSL_write(), because that would produce livelock,
126 * e.g. in this situation:
128 * - SSL_write() blocks, so tx_want gets SSL_READING or SSL_WRITING.
130 * - SSL_read() blocks, so rx_want gets SSL_READING or SSL_WRITING,
131 * but tx_want gets reset to SSL_NOTHING.
133 * - Client calls stream_wait(STREAM_RECV) and stream_wait(STREAM_SEND)
136 * - Client wakes up immediately since SSL_NOTHING in tx_want indicates
137 * that no blocking is necessary.
139 * The solution we adopt here is to set tx_want to SSL_NOTHING after
140 * calling SSL_read() only if the SSL state of the connection changed,
141 * which indicates that an SSL-level renegotiation made some progress, and
142 * similarly for rx_want and SSL_write(). This prevents both the
143 * deadlock and livelock situations above.
145 int rx_want, tx_want;
147 /* A few bytes of header data in case SSL negotiation fails. */
152 /* SSL context created by ssl_init(). */
155 struct ssl_config_file {
156 bool read; /* Whether the file was successfully read. */
157 char *file_name; /* Configured file name, if any. */
158 struct timespec mtime; /* File mtime as of last time we read it. */
161 /* SSL configuration files. */
162 static struct ssl_config_file private_key;
163 static struct ssl_config_file certificate;
164 static struct ssl_config_file ca_cert;
166 /* Ordinarily, the SSL client and server verify each other's certificates using
167 * a CA certificate. Setting this to false disables this behavior. (This is a
169 static bool verify_peer_cert = true;
171 /* Ordinarily, we require a CA certificate for the peer to be locally
172 * available. We can, however, bootstrap the CA certificate from the peer at
173 * the beginning of our first connection then use that certificate on all
174 * subsequent connections, saving it to a file for use in future runs also. In
175 * this case, 'bootstrap_ca_cert' is true. */
176 static bool bootstrap_ca_cert;
178 /* Session number. Used in debug logging messages to uniquely identify a
180 static unsigned int next_session_nr;
182 /* Who knows what can trigger various SSL errors, so let's throttle them down
184 static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(10, 25);
186 static int ssl_init(void);
187 static int do_ssl_init(void);
188 static bool ssl_wants_io(int ssl_error);
189 static void ssl_close(struct stream *);
190 static void ssl_clear_txbuf(struct ssl_stream *);
191 static void interpret_queued_ssl_error(const char *function);
192 static int interpret_ssl_error(const char *function, int ret, int error,
194 static DH *tmp_dh_callback(SSL *ssl, int is_export OVS_UNUSED, int keylength);
195 static void log_ca_cert(const char *file_name, X509 *cert);
196 static void stream_ssl_set_ca_cert_file__(const char *file_name,
197 bool bootstrap, bool force);
198 static void ssl_protocol_cb(int write_p, int version, int content_type,
199 const void *, size_t, SSL *, void *sslv_);
200 static bool update_ssl_config(struct ssl_config_file *, const char *file_name);
201 static int sock_errno(void);
204 want_to_poll_events(int want)
222 setsockopt_tcp_nodelay(int fd)
227 retval = setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &on, sizeof on);
229 retval = sock_errno();
230 VLOG_ERR("setsockopt(TCP_NODELAY): %s", sock_strerror(retval));
236 new_ssl_stream(const char *name, int fd, enum session_type type,
237 enum ssl_state state, struct stream **streamp)
239 struct sockaddr_storage local;
240 socklen_t local_len = sizeof local;
241 struct ssl_stream *sslv;
245 /* Check for all the needful configuration. */
247 if (!private_key.read) {
248 VLOG_ERR("Private key must be configured to use SSL");
249 retval = ENOPROTOOPT;
251 if (!certificate.read) {
252 VLOG_ERR("Certificate must be configured to use SSL");
253 retval = ENOPROTOOPT;
255 if (!ca_cert.read && verify_peer_cert && !bootstrap_ca_cert) {
256 VLOG_ERR("CA certificate must be configured to use SSL");
257 retval = ENOPROTOOPT;
259 if (!retval && !SSL_CTX_check_private_key(ctx)) {
260 VLOG_ERR("Private key does not match certificate public key: %s",
261 ERR_error_string(ERR_get_error(), NULL));
262 retval = ENOPROTOOPT;
268 /* Get the local IP and port information */
269 retval = getsockname(fd, (struct sockaddr *) &local, &local_len);
271 memset(&local, 0, sizeof local);
275 * On windows platforms, this can only be called upon TCP connected.
277 if (state == STATE_SSL_CONNECTING) {
278 retval = setsockopt_tcp_nodelay(fd);
284 /* Create and configure OpenSSL stream. */
287 VLOG_ERR("SSL_new: %s", ERR_error_string(ERR_get_error(), NULL));
288 retval = ENOPROTOOPT;
291 if (SSL_set_fd(ssl, fd) == 0) {
292 VLOG_ERR("SSL_set_fd: %s", ERR_error_string(ERR_get_error(), NULL));
293 retval = ENOPROTOOPT;
296 if (!verify_peer_cert || (bootstrap_ca_cert && type == CLIENT)) {
297 SSL_set_verify(ssl, SSL_VERIFY_NONE, NULL);
300 /* Create and return the ssl_stream. */
301 sslv = xmalloc(sizeof *sslv);
302 stream_init(&sslv->stream, &ssl_stream_class, EAGAIN, name);
308 sslv->rx_want = sslv->tx_want = SSL_NOTHING;
309 sslv->session_nr = next_session_nr++;
312 if (VLOG_IS_DBG_ENABLED()) {
313 SSL_set_msg_callback(ssl, ssl_protocol_cb);
314 SSL_set_msg_callback_arg(ssl, sslv);
317 *streamp = &sslv->stream;
328 static struct ssl_stream *
329 ssl_stream_cast(struct stream *stream)
331 stream_assert_class(stream, &ssl_stream_class);
332 return CONTAINER_OF(stream, struct ssl_stream, stream);
336 ssl_open(const char *name, char *suffix, struct stream **streamp, uint8_t dscp)
345 error = inet_open_active(SOCK_STREAM, suffix, OFP_OLD_PORT, NULL, &fd,
348 int state = error ? STATE_TCP_CONNECTING : STATE_SSL_CONNECTING;
349 return new_ssl_stream(name, fd, CLIENT, state, streamp);
351 VLOG_ERR("%s: connect: %s", name, ovs_strerror(error));
357 do_ca_cert_bootstrap(struct stream *stream)
359 struct ssl_stream *sslv = ssl_stream_cast(stream);
360 STACK_OF(X509) *chain;
366 chain = SSL_get_peer_cert_chain(sslv->ssl);
367 if (!chain || !sk_X509_num(chain)) {
368 VLOG_ERR("could not bootstrap CA cert: no certificate presented by "
372 cert = sk_X509_value(chain, sk_X509_num(chain) - 1);
374 /* Check that 'cert' is self-signed. Otherwise it is not a CA
375 * certificate and we should not attempt to use it as one. */
376 error = X509_check_issued(cert, cert);
378 VLOG_ERR("could not bootstrap CA cert: obtained certificate is "
379 "not self-signed (%s)",
380 X509_verify_cert_error_string(error));
381 if (sk_X509_num(chain) < 2) {
382 VLOG_ERR("only one certificate was received, so probably the peer "
383 "is not configured to send its CA certificate");
388 fd = open(ca_cert.file_name, O_CREAT | O_EXCL | O_WRONLY, 0444);
390 if (errno == EEXIST) {
391 VLOG_INFO_RL(&rl, "reading CA cert %s created by another process",
393 stream_ssl_set_ca_cert_file__(ca_cert.file_name, true, true);
396 VLOG_ERR("could not bootstrap CA cert: creating %s failed: %s",
397 ca_cert.file_name, ovs_strerror(errno));
402 file = fdopen(fd, "w");
405 VLOG_ERR("could not bootstrap CA cert: fdopen failed: %s",
406 ovs_strerror(error));
407 unlink(ca_cert.file_name);
411 if (!PEM_write_X509(file, cert)) {
412 VLOG_ERR("could not bootstrap CA cert: PEM_write_X509 to %s failed: "
413 "%s", ca_cert.file_name,
414 ERR_error_string(ERR_get_error(), NULL));
416 unlink(ca_cert.file_name);
422 VLOG_ERR("could not bootstrap CA cert: writing %s failed: %s",
423 ca_cert.file_name, ovs_strerror(error));
424 unlink(ca_cert.file_name);
428 VLOG_INFO("successfully bootstrapped CA cert to %s", ca_cert.file_name);
429 log_ca_cert(ca_cert.file_name, cert);
430 bootstrap_ca_cert = false;
433 /* SSL_CTX_add_client_CA makes a copy of cert's relevant data. */
434 SSL_CTX_add_client_CA(ctx, cert);
436 /* SSL_CTX_use_certificate() takes ownership of the certificate passed in.
437 * 'cert' is owned by sslv->ssl, so we need to duplicate it. */
438 cert = X509_dup(cert);
442 SSL_CTX_set_cert_store(ctx, X509_STORE_new());
443 if (SSL_CTX_load_verify_locations(ctx, ca_cert.file_name, NULL) != 1) {
444 VLOG_ERR("SSL_CTX_load_verify_locations: %s",
445 ERR_error_string(ERR_get_error(), NULL));
448 VLOG_INFO("killing successful connection to retry using CA cert");
453 ssl_connect(struct stream *stream)
455 struct ssl_stream *sslv = ssl_stream_cast(stream);
458 switch (sslv->state) {
459 case STATE_TCP_CONNECTING:
460 retval = check_connection_completion(sslv->fd);
464 sslv->state = STATE_SSL_CONNECTING;
465 retval = setsockopt_tcp_nodelay(sslv->fd);
471 case STATE_SSL_CONNECTING:
472 /* Capture the first few bytes of received data so that we can guess
473 * what kind of funny data we've been sent if SSL negotiation fails. */
474 if (sslv->n_head <= 0) {
475 sslv->n_head = recv(sslv->fd, sslv->head, sizeof sslv->head,
479 retval = (sslv->type == CLIENT
480 ? SSL_connect(sslv->ssl) : SSL_accept(sslv->ssl));
482 int error = SSL_get_error(sslv->ssl, retval);
483 if (retval < 0 && ssl_wants_io(error)) {
488 interpret_ssl_error((sslv->type == CLIENT ? "SSL_connect"
489 : "SSL_accept"), retval, error, &unused);
490 shutdown(sslv->fd, SHUT_RDWR);
491 stream_report_content(sslv->head, sslv->n_head, STREAM_SSL,
492 THIS_MODULE, stream_get_name(stream));
495 } else if (bootstrap_ca_cert) {
496 return do_ca_cert_bootstrap(stream);
497 } else if (verify_peer_cert
498 && ((SSL_get_verify_mode(sslv->ssl)
499 & (SSL_VERIFY_NONE | SSL_VERIFY_PEER))
500 != SSL_VERIFY_PEER)) {
501 /* Two or more SSL connections completed at the same time while we
502 * were in bootstrap mode. Only one of these can finish the
503 * bootstrap successfully. The other one(s) must be rejected
504 * because they were not verified against the bootstrapped CA
505 * certificate. (Alternatively we could verify them against the CA
506 * certificate, but that's more trouble than it's worth. These
507 * connections will succeed the next time they retry, assuming that
508 * they have a certificate against the correct CA.) */
509 VLOG_INFO("rejecting SSL connection during bootstrap race window");
520 ssl_close(struct stream *stream)
522 struct ssl_stream *sslv = ssl_stream_cast(stream);
523 ssl_clear_txbuf(sslv);
525 /* Attempt clean shutdown of the SSL connection. This will work most of
526 * the time, as long as the kernel send buffer has some free space and the
527 * SSL connection isn't renegotiating, etc. That has to be good enough,
528 * since we don't have any way to continue the close operation in the
530 SSL_shutdown(sslv->ssl);
532 /* SSL_shutdown() might have signaled an error, in which case we need to
533 * flush it out of the OpenSSL error queue or the next OpenSSL operation
534 * will falsely signal an error. */
538 closesocket(sslv->fd);
543 interpret_queued_ssl_error(const char *function)
545 int queued_error = ERR_get_error();
546 if (queued_error != 0) {
547 VLOG_WARN_RL(&rl, "%s: %s",
548 function, ERR_error_string(queued_error, NULL));
550 VLOG_ERR_RL(&rl, "%s: SSL_ERROR_SSL without queued error", function);
555 interpret_ssl_error(const char *function, int ret, int error,
562 VLOG_ERR_RL(&rl, "%s: unexpected SSL_ERROR_NONE", function);
565 case SSL_ERROR_ZERO_RETURN:
566 VLOG_ERR_RL(&rl, "%s: unexpected SSL_ERROR_ZERO_RETURN", function);
569 case SSL_ERROR_WANT_READ:
573 case SSL_ERROR_WANT_WRITE:
577 case SSL_ERROR_WANT_CONNECT:
578 VLOG_ERR_RL(&rl, "%s: unexpected SSL_ERROR_WANT_CONNECT", function);
581 case SSL_ERROR_WANT_ACCEPT:
582 VLOG_ERR_RL(&rl, "%s: unexpected SSL_ERROR_WANT_ACCEPT", function);
585 case SSL_ERROR_WANT_X509_LOOKUP:
586 VLOG_ERR_RL(&rl, "%s: unexpected SSL_ERROR_WANT_X509_LOOKUP",
590 case SSL_ERROR_SYSCALL: {
591 int queued_error = ERR_get_error();
592 if (queued_error == 0) {
595 VLOG_WARN_RL(&rl, "%s: system error (%s)",
596 function, ovs_strerror(status));
599 VLOG_WARN_RL(&rl, "%s: unexpected SSL connection close",
604 VLOG_WARN_RL(&rl, "%s: %s",
605 function, ERR_error_string(queued_error, NULL));
611 interpret_queued_ssl_error(function);
615 VLOG_ERR_RL(&rl, "%s: bad SSL error code %d", function, error);
622 ssl_recv(struct stream *stream, void *buffer, size_t n)
624 struct ssl_stream *sslv = ssl_stream_cast(stream);
628 /* Behavior of zero-byte SSL_read is poorly defined. */
631 old_state = SSL_get_state(sslv->ssl);
632 ret = SSL_read(sslv->ssl, buffer, n);
633 if (old_state != SSL_get_state(sslv->ssl)) {
634 sslv->tx_want = SSL_NOTHING;
636 sslv->rx_want = SSL_NOTHING;
641 int error = SSL_get_error(sslv->ssl, ret);
642 if (error == SSL_ERROR_ZERO_RETURN) {
645 return -interpret_ssl_error("SSL_read", ret, error,
652 ssl_clear_txbuf(struct ssl_stream *sslv)
654 ofpbuf_delete(sslv->txbuf);
659 ssl_do_tx(struct stream *stream)
661 struct ssl_stream *sslv = ssl_stream_cast(stream);
664 int old_state = SSL_get_state(sslv->ssl);
665 int ret = SSL_write(sslv->ssl,
666 ofpbuf_data(sslv->txbuf), ofpbuf_size(sslv->txbuf));
667 if (old_state != SSL_get_state(sslv->ssl)) {
668 sslv->rx_want = SSL_NOTHING;
670 sslv->tx_want = SSL_NOTHING;
672 ofpbuf_pull(sslv->txbuf, ret);
673 if (ofpbuf_size(sslv->txbuf) == 0) {
677 int ssl_error = SSL_get_error(sslv->ssl, ret);
678 if (ssl_error == SSL_ERROR_ZERO_RETURN) {
679 VLOG_WARN_RL(&rl, "SSL_write: connection closed");
682 return interpret_ssl_error("SSL_write", ret, ssl_error,
690 ssl_send(struct stream *stream, const void *buffer, size_t n)
692 struct ssl_stream *sslv = ssl_stream_cast(stream);
699 sslv->txbuf = ofpbuf_clone_data(buffer, n);
700 error = ssl_do_tx(stream);
703 ssl_clear_txbuf(sslv);
715 ssl_run(struct stream *stream)
717 struct ssl_stream *sslv = ssl_stream_cast(stream);
719 if (sslv->txbuf && ssl_do_tx(stream) != EAGAIN) {
720 ssl_clear_txbuf(sslv);
725 ssl_run_wait(struct stream *stream)
727 struct ssl_stream *sslv = ssl_stream_cast(stream);
729 if (sslv->tx_want != SSL_NOTHING) {
730 poll_fd_wait(sslv->fd, want_to_poll_events(sslv->tx_want));
735 ssl_wait(struct stream *stream, enum stream_wait_type wait)
737 struct ssl_stream *sslv = ssl_stream_cast(stream);
741 if (stream_connect(stream) != EAGAIN) {
742 poll_immediate_wake();
744 switch (sslv->state) {
745 case STATE_TCP_CONNECTING:
746 poll_fd_wait(sslv->fd, POLLOUT);
749 case STATE_SSL_CONNECTING:
750 /* ssl_connect() called SSL_accept() or SSL_connect(), which
751 * set up the status that we test here. */
752 poll_fd_wait(sslv->fd,
753 want_to_poll_events(SSL_want(sslv->ssl)));
763 if (sslv->rx_want != SSL_NOTHING) {
764 poll_fd_wait(sslv->fd, want_to_poll_events(sslv->rx_want));
766 poll_immediate_wake();
772 /* We have room in our tx queue. */
773 poll_immediate_wake();
775 /* stream_run_wait() will do the right thing; don't bother with
785 const struct stream_class ssl_stream_class = {
787 true, /* needs_probes */
789 ssl_close, /* close */
790 ssl_connect, /* connect */
794 ssl_run_wait, /* run_wait */
802 struct pstream pstream;
806 const struct pstream_class pssl_pstream_class;
808 static struct pssl_pstream *
809 pssl_pstream_cast(struct pstream *pstream)
811 pstream_assert_class(pstream, &pssl_pstream_class);
812 return CONTAINER_OF(pstream, struct pssl_pstream, pstream);
816 pssl_open(const char *name OVS_UNUSED, char *suffix, struct pstream **pstreamp,
819 char bound_name[SS_NTOP_BUFSIZE + 16];
820 char addrbuf[SS_NTOP_BUFSIZE];
821 struct sockaddr_storage ss;
822 struct pssl_pstream *pssl;
832 fd = inet_open_passive(SOCK_STREAM, suffix, OFP_OLD_PORT, &ss, dscp, true);
837 port = ss_get_port(&ss);
838 snprintf(bound_name, sizeof bound_name, "ptcp:%"PRIu16":%s",
839 port, ss_format_address(&ss, addrbuf, sizeof addrbuf));
841 pssl = xmalloc(sizeof *pssl);
842 pstream_init(&pssl->pstream, &pssl_pstream_class, bound_name);
843 pstream_set_bound_port(&pssl->pstream, htons(port));
845 *pstreamp = &pssl->pstream;
850 pssl_close(struct pstream *pstream)
852 struct pssl_pstream *pssl = pssl_pstream_cast(pstream);
853 closesocket(pssl->fd);
858 pssl_accept(struct pstream *pstream, struct stream **new_streamp)
860 struct pssl_pstream *pssl = pssl_pstream_cast(pstream);
861 char name[SS_NTOP_BUFSIZE + 16];
862 char addrbuf[SS_NTOP_BUFSIZE];
863 struct sockaddr_storage ss;
864 socklen_t ss_len = sizeof ss;
868 new_fd = accept(pssl->fd, (struct sockaddr *) &ss, &ss_len);
870 error = sock_errno();
872 if (error == WSAEWOULDBLOCK) {
876 if (error != EAGAIN) {
877 VLOG_DBG_RL(&rl, "accept: %s", sock_strerror(error));
882 error = set_nonblocking(new_fd);
888 snprintf(name, sizeof name, "tcp:%s:%"PRIu16,
889 ss_format_address(&ss, addrbuf, sizeof addrbuf),
891 return new_ssl_stream(name, new_fd, SERVER, STATE_SSL_CONNECTING,
896 pssl_wait(struct pstream *pstream)
898 struct pssl_pstream *pssl = pssl_pstream_cast(pstream);
899 poll_fd_wait(pssl->fd, POLLIN);
903 pssl_set_dscp(struct pstream *pstream, uint8_t dscp)
905 struct pssl_pstream *pssl = pssl_pstream_cast(pstream);
906 return set_dscp(pssl->fd, dscp);
909 const struct pstream_class pssl_pstream_class = {
920 * Returns true if OpenSSL error is WANT_READ or WANT_WRITE, indicating that
921 * OpenSSL is requesting that we call it back when the socket is ready for read
922 * or writing, respectively.
925 ssl_wants_io(int ssl_error)
927 return (ssl_error == SSL_ERROR_WANT_WRITE
928 || ssl_error == SSL_ERROR_WANT_READ);
934 static int init_status = -1;
935 if (init_status < 0) {
936 init_status = do_ssl_init();
937 ovs_assert(init_status >= 0);
948 /* The following call is needed if we "#include <openssl/applink.c>". */
949 CRYPTO_malloc_init();
952 SSL_load_error_strings();
954 if (!RAND_status()) {
955 /* We occasionally see OpenSSL fail to seed its random number generator
956 * in heavily loaded hypervisors. I suspect the following scenario:
958 * 1. OpenSSL calls read() to get 32 bytes from /dev/urandom.
959 * 2. The kernel generates 10 bytes of randomness and copies it out.
960 * 3. A signal arrives (perhaps SIGALRM).
961 * 4. The kernel interrupts the system call to service the signal.
962 * 5. Userspace gets 10 bytes of entropy.
963 * 6. OpenSSL doesn't read again to get the final 22 bytes. Therefore
964 * OpenSSL doesn't have enough entropy to consider itself
967 * The only part I'm not entirely sure about is #6, because the OpenSSL
968 * code is so hard to read. */
972 VLOG_WARN("OpenSSL random seeding failed, reseeding ourselves");
974 retval = get_entropy(seed, sizeof seed);
976 VLOG_ERR("failed to obtain entropy (%s)",
977 ovs_retval_to_string(retval));
978 return retval > 0 ? retval : ENOPROTOOPT;
981 RAND_seed(seed, sizeof seed);
984 /* OpenSSL has a bunch of "connection methods": SSLv2_method(),
985 * SSLv3_method(), TLSv1_method(), SSLv23_method(), ... Most of these
986 * support exactly one version of SSL, e.g. TLSv1_method() supports TLSv1
987 * only, not any earlier *or later* version. The only exception is
988 * SSLv23_method(), which in fact supports *any* version of SSL and TLS.
989 * We don't want SSLv2 or SSLv3 support, so we turn it off below with
990 * SSL_CTX_set_options().
992 * The cast is needed to avoid a warning with newer versions of OpenSSL in
993 * which SSLv23_method() returns a "const" pointer. */
994 method = CONST_CAST(SSL_METHOD *, SSLv23_method());
995 if (method == NULL) {
996 VLOG_ERR("TLSv1_method: %s", ERR_error_string(ERR_get_error(), NULL));
1000 ctx = SSL_CTX_new(method);
1002 VLOG_ERR("SSL_CTX_new: %s", ERR_error_string(ERR_get_error(), NULL));
1005 SSL_CTX_set_options(ctx, SSL_OP_NO_SSLv2 | SSL_OP_NO_SSLv3);
1006 SSL_CTX_set_tmp_dh_callback(ctx, tmp_dh_callback);
1007 SSL_CTX_set_mode(ctx, SSL_MODE_ENABLE_PARTIAL_WRITE);
1008 SSL_CTX_set_mode(ctx, SSL_MODE_ACCEPT_MOVING_WRITE_BUFFER);
1009 SSL_CTX_set_verify(ctx, SSL_VERIFY_PEER | SSL_VERIFY_FAIL_IF_NO_PEER_CERT,
1016 tmp_dh_callback(SSL *ssl OVS_UNUSED, int is_export OVS_UNUSED, int keylength)
1021 DH *(*constructor)(void);
1024 static struct dh dh_table[] = {
1025 {1024, NULL, get_dh1024},
1026 {2048, NULL, get_dh2048},
1027 {4096, NULL, get_dh4096},
1032 for (dh = dh_table; dh < &dh_table[ARRAY_SIZE(dh_table)]; dh++) {
1033 if (dh->keylength == keylength) {
1035 dh->dh = dh->constructor();
1043 VLOG_ERR_RL(&rl, "no Diffie-Hellman parameters for key length %d",
1048 /* Returns true if SSL is at least partially configured. */
1050 stream_ssl_is_configured(void)
1052 return private_key.file_name || certificate.file_name || ca_cert.file_name;
1056 update_ssl_config(struct ssl_config_file *config, const char *file_name)
1058 struct timespec mtime;
1061 if (ssl_init() || !file_name) {
1065 /* If the file name hasn't changed and neither has the file contents, stop
1067 error = get_mtime(file_name, &mtime);
1068 if (error && error != ENOENT) {
1069 VLOG_ERR_RL(&rl, "%s: stat failed (%s)",
1070 file_name, ovs_strerror(error));
1072 if (config->file_name
1073 && !strcmp(config->file_name, file_name)
1074 && mtime.tv_sec == config->mtime.tv_sec
1075 && mtime.tv_nsec == config->mtime.tv_nsec) {
1079 /* Update 'config'. */
1080 config->mtime = mtime;
1081 if (file_name != config->file_name) {
1082 free(config->file_name);
1083 config->file_name = xstrdup(file_name);
1089 stream_ssl_set_private_key_file__(const char *file_name)
1091 if (SSL_CTX_use_PrivateKey_file(ctx, file_name, SSL_FILETYPE_PEM) == 1) {
1092 private_key.read = true;
1094 VLOG_ERR("SSL_use_PrivateKey_file: %s",
1095 ERR_error_string(ERR_get_error(), NULL));
1100 stream_ssl_set_private_key_file(const char *file_name)
1102 if (update_ssl_config(&private_key, file_name)) {
1103 stream_ssl_set_private_key_file__(file_name);
1108 stream_ssl_set_certificate_file__(const char *file_name)
1110 if (SSL_CTX_use_certificate_chain_file(ctx, file_name) == 1) {
1111 certificate.read = true;
1113 VLOG_ERR("SSL_use_certificate_file: %s",
1114 ERR_error_string(ERR_get_error(), NULL));
1119 stream_ssl_set_certificate_file(const char *file_name)
1121 if (update_ssl_config(&certificate, file_name)) {
1122 stream_ssl_set_certificate_file__(file_name);
1126 /* Sets the private key and certificate files in one operation. Use this
1127 * interface, instead of calling stream_ssl_set_private_key_file() and
1128 * stream_ssl_set_certificate_file() individually, in the main loop of a
1129 * long-running program whose key and certificate might change at runtime.
1131 * This is important because of OpenSSL's behavior. If an OpenSSL context
1132 * already has a certificate, and stream_ssl_set_private_key_file() is called
1133 * to install a new private key, OpenSSL will report an error because the new
1134 * private key does not match the old certificate. The other order, of setting
1135 * a new certificate, then setting a new private key, does work.
1137 * If this were the only problem, calling stream_ssl_set_certificate_file()
1138 * before stream_ssl_set_private_key_file() would fix it. But, if the private
1139 * key is changed before the certificate (e.g. someone "scp"s or "mv"s the new
1140 * private key in place before the certificate), then OpenSSL would reject that
1141 * change, and then the change of certificate would succeed, but there would be
1142 * no associated private key (because it had only changed once and therefore
1143 * there was no point in re-reading it).
1145 * This function avoids both problems by, whenever either the certificate or
1146 * the private key file changes, re-reading both of them, in the correct order.
1149 stream_ssl_set_key_and_cert(const char *private_key_file,
1150 const char *certificate_file)
1152 if (update_ssl_config(&private_key, private_key_file)
1153 || update_ssl_config(&certificate, certificate_file)) {
1154 stream_ssl_set_certificate_file__(certificate_file);
1155 stream_ssl_set_private_key_file__(private_key_file);
1159 /* Reads the X509 certificate or certificates in file 'file_name'. On success,
1160 * stores the address of the first element in an array of pointers to
1161 * certificates in '*certs' and the number of certificates in the array in
1162 * '*n_certs', and returns 0. On failure, stores a null pointer in '*certs', 0
1163 * in '*n_certs', and returns a positive errno value.
1165 * The caller is responsible for freeing '*certs'. */
1167 read_cert_file(const char *file_name, X509 ***certs, size_t *n_certs)
1170 size_t allocated_certs = 0;
1175 file = fopen(file_name, "r");
1177 VLOG_ERR("failed to open %s for reading: %s",
1178 file_name, ovs_strerror(errno));
1186 /* Read certificate from file. */
1187 certificate = PEM_read_X509(file, NULL, NULL, NULL);
1191 VLOG_ERR("PEM_read_X509 failed reading %s: %s",
1192 file_name, ERR_error_string(ERR_get_error(), NULL));
1193 for (i = 0; i < *n_certs; i++) {
1194 X509_free((*certs)[i]);
1202 /* Add certificate to array. */
1203 if (*n_certs >= allocated_certs) {
1204 *certs = x2nrealloc(*certs, &allocated_certs, sizeof **certs);
1206 (*certs)[(*n_certs)++] = certificate;
1208 /* Are there additional certificates in the file? */
1211 } while (isspace(c));
1222 /* Sets 'file_name' as the name of a file containing one or more X509
1223 * certificates to send to the peer. Typical use in OpenFlow is to send the CA
1224 * certificate to the peer, which enables a switch to pick up the controller's
1225 * CA certificate on its first connection. */
1227 stream_ssl_set_peer_ca_cert_file(const char *file_name)
1237 if (!read_cert_file(file_name, &certs, &n_certs)) {
1238 for (i = 0; i < n_certs; i++) {
1239 if (SSL_CTX_add_extra_chain_cert(ctx, certs[i]) != 1) {
1240 VLOG_ERR("SSL_CTX_add_extra_chain_cert: %s",
1241 ERR_error_string(ERR_get_error(), NULL));
1248 /* Logs fingerprint of CA certificate 'cert' obtained from 'file_name'. */
1250 log_ca_cert(const char *file_name, X509 *cert)
1252 unsigned char digest[EVP_MAX_MD_SIZE];
1253 unsigned int n_bytes;
1258 if (!X509_digest(cert, EVP_sha1(), digest, &n_bytes)) {
1259 ds_put_cstr(&fp, "<out of memory>");
1262 for (i = 0; i < n_bytes; i++) {
1264 ds_put_char(&fp, ':');
1266 ds_put_format(&fp, "%02x", digest[i]);
1269 subject = X509_NAME_oneline(X509_get_subject_name(cert), NULL, 0);
1270 VLOG_INFO("Trusting CA cert from %s (%s) (fingerprint %s)", file_name,
1271 subject ? subject : "<out of memory>", ds_cstr(&fp));
1272 OPENSSL_free(subject);
1277 stream_ssl_set_ca_cert_file__(const char *file_name,
1278 bool bootstrap, bool force)
1284 if (!update_ssl_config(&ca_cert, file_name) && !force) {
1288 if (!strcmp(file_name, "none")) {
1289 verify_peer_cert = false;
1290 VLOG_WARN("Peer certificate validation disabled "
1291 "(this is a security risk)");
1292 } else if (bootstrap && stat(file_name, &s) && errno == ENOENT) {
1293 bootstrap_ca_cert = true;
1294 } else if (!read_cert_file(file_name, &certs, &n_certs)) {
1297 /* Set up list of CAs that the server will accept from the client. */
1298 for (i = 0; i < n_certs; i++) {
1299 /* SSL_CTX_add_client_CA makes a copy of the relevant data. */
1300 if (SSL_CTX_add_client_CA(ctx, certs[i]) != 1) {
1301 VLOG_ERR("failed to add client certificate %"PRIuSIZE" from %s: %s",
1303 ERR_error_string(ERR_get_error(), NULL));
1305 log_ca_cert(file_name, certs[i]);
1307 X509_free(certs[i]);
1311 /* Set up CAs for OpenSSL to trust in verifying the peer's
1313 SSL_CTX_set_cert_store(ctx, X509_STORE_new());
1314 if (SSL_CTX_load_verify_locations(ctx, file_name, NULL) != 1) {
1315 VLOG_ERR("SSL_CTX_load_verify_locations: %s",
1316 ERR_error_string(ERR_get_error(), NULL));
1320 bootstrap_ca_cert = false;
1322 ca_cert.read = true;
1325 /* Sets 'file_name' as the name of the file from which to read the CA
1326 * certificate used to verify the peer within SSL connections. If 'bootstrap'
1327 * is false, the file must exist. If 'bootstrap' is false, then the file is
1328 * read if it is exists; if it does not, then it will be created from the CA
1329 * certificate received from the peer on the first SSL connection. */
1331 stream_ssl_set_ca_cert_file(const char *file_name, bool bootstrap)
1333 stream_ssl_set_ca_cert_file__(file_name, bootstrap, false);
1336 /* SSL protocol logging. */
1339 ssl_alert_level_to_string(uint8_t type)
1342 case 1: return "warning";
1343 case 2: return "fatal";
1344 default: return "<unknown>";
1349 ssl_alert_description_to_string(uint8_t type)
1352 case 0: return "close_notify";
1353 case 10: return "unexpected_message";
1354 case 20: return "bad_record_mac";
1355 case 21: return "decryption_failed";
1356 case 22: return "record_overflow";
1357 case 30: return "decompression_failure";
1358 case 40: return "handshake_failure";
1359 case 42: return "bad_certificate";
1360 case 43: return "unsupported_certificate";
1361 case 44: return "certificate_revoked";
1362 case 45: return "certificate_expired";
1363 case 46: return "certificate_unknown";
1364 case 47: return "illegal_parameter";
1365 case 48: return "unknown_ca";
1366 case 49: return "access_denied";
1367 case 50: return "decode_error";
1368 case 51: return "decrypt_error";
1369 case 60: return "export_restriction";
1370 case 70: return "protocol_version";
1371 case 71: return "insufficient_security";
1372 case 80: return "internal_error";
1373 case 90: return "user_canceled";
1374 case 100: return "no_renegotiation";
1375 default: return "<unknown>";
1380 ssl_handshake_type_to_string(uint8_t type)
1383 case 0: return "hello_request";
1384 case 1: return "client_hello";
1385 case 2: return "server_hello";
1386 case 11: return "certificate";
1387 case 12: return "server_key_exchange";
1388 case 13: return "certificate_request";
1389 case 14: return "server_hello_done";
1390 case 15: return "certificate_verify";
1391 case 16: return "client_key_exchange";
1392 case 20: return "finished";
1393 default: return "<unknown>";
1398 ssl_protocol_cb(int write_p, int version OVS_UNUSED, int content_type,
1399 const void *buf_, size_t len, SSL *ssl OVS_UNUSED, void *sslv_)
1401 const struct ssl_stream *sslv = sslv_;
1402 const uint8_t *buf = buf_;
1405 if (!VLOG_IS_DBG_ENABLED()) {
1410 if (content_type == 20) {
1411 ds_put_cstr(&details, "change_cipher_spec");
1412 } else if (content_type == 21) {
1413 ds_put_format(&details, "alert: %s, %s",
1414 ssl_alert_level_to_string(buf[0]),
1415 ssl_alert_description_to_string(buf[1]));
1416 } else if (content_type == 22) {
1417 ds_put_format(&details, "handshake: %s",
1418 ssl_handshake_type_to_string(buf[0]));
1420 ds_put_format(&details, "type %d", content_type);
1423 VLOG_DBG("%s%u%s%s %s (%"PRIuSIZE" bytes)",
1424 sslv->type == CLIENT ? "client" : "server",
1425 sslv->session_nr, write_p ? "-->" : "<--",
1426 stream_get_name(&sslv->stream), ds_cstr(&details), len);
1428 ds_destroy(&details);