2 * Copyright (c) 2008, 2009, 2010, 2011 Nicira Networks.
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at:
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
18 #include "stream-ssl.h"
25 #include <sys/types.h>
26 #include <sys/socket.h>
27 #include <netinet/tcp.h>
28 #include <openssl/err.h>
29 #include <openssl/ssl.h>
30 #include <openssl/x509v3.h>
32 #include <sys/fcntl.h>
36 #include "dynamic-string.h"
37 #include "leak-checker.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);
52 COVERAGE_DEFINE(ssl_session);
53 COVERAGE_DEFINE(ssl_session_reused);
71 enum session_type type;
75 unsigned int session_nr;
77 /* rx_want and tx_want record the result of the last call to SSL_read()
78 * and SSL_write(), respectively:
80 * - If the call reported that data needed to be read from the file
81 * descriptor, the corresponding member is set to SSL_READING.
83 * - If the call reported that data needed to be written to the file
84 * descriptor, the corresponding member is set to SSL_WRITING.
86 * - Otherwise, the member is set to SSL_NOTHING, indicating that the
87 * call completed successfully (or with an error) and that there is no
90 * These are needed because there is no way to ask OpenSSL what a data read
91 * or write would require without giving it a buffer to receive into or
92 * data to send, respectively. (Note that the SSL_want() status is
93 * overwritten by each SSL_read() or SSL_write() call, so we can't rely on
96 * A single call to SSL_read() or SSL_write() can perform both reading
97 * and writing and thus invalidate not one of these values but actually
98 * both. Consider this situation, for example:
100 * - SSL_write() blocks on a read, so tx_want gets SSL_READING.
102 * - SSL_read() laters succeeds reading from 'fd' and clears out the
103 * whole receive buffer, so rx_want gets SSL_READING.
105 * - Client calls stream_wait(STREAM_RECV) and stream_wait(STREAM_SEND)
108 * - Now we're stuck blocking until the peer sends us data, even though
109 * SSL_write() could now succeed, which could easily be a deadlock
112 * On the other hand, we can't reset both tx_want and rx_want on every call
113 * to SSL_read() or SSL_write(), because that would produce livelock,
114 * e.g. in this situation:
116 * - SSL_write() blocks, so tx_want gets SSL_READING or SSL_WRITING.
118 * - SSL_read() blocks, so rx_want gets SSL_READING or SSL_WRITING,
119 * but tx_want gets reset to SSL_NOTHING.
121 * - Client calls stream_wait(STREAM_RECV) and stream_wait(STREAM_SEND)
124 * - Client wakes up immediately since SSL_NOTHING in tx_want indicates
125 * that no blocking is necessary.
127 * The solution we adopt here is to set tx_want to SSL_NOTHING after
128 * calling SSL_read() only if the SSL state of the connection changed,
129 * which indicates that an SSL-level renegotiation made some progress, and
130 * similarly for rx_want and SSL_write(). This prevents both the
131 * deadlock and livelock situations above.
133 int rx_want, tx_want;
135 /* A few bytes of header data in case SSL negotiation fails. */
140 /* SSL context created by ssl_init(). */
143 /* Maps from stream target (e.g. "127.0.0.1:1234") to SSL_SESSION *. The
144 * sessions are those from the last SSL connection to the given target.
145 * OpenSSL caches server-side sessions internally, so this cache is only used
146 * for client connections.
148 * The stream_ssl module owns a reference to each of the sessions in this
149 * table, so they must be freed with SSL_SESSION_free() when they are no
151 static struct shash client_sessions = SHASH_INITIALIZER(&client_sessions);
153 /* Maximum number of client sessions to cache. Ordinarily I'd expect that one
154 * session would be sufficient but this should cover it. */
155 #define MAX_CLIENT_SESSION_CACHE 16
157 struct ssl_config_file {
158 bool read; /* Whether the file was successfully read. */
159 char *file_name; /* Configured file name, if any. */
160 struct timespec mtime; /* File mtime as of last time we read it. */
163 /* SSL configuration files. */
164 static struct ssl_config_file private_key;
165 static struct ssl_config_file certificate;
166 static struct ssl_config_file ca_cert;
168 /* Ordinarily, the SSL client and server verify each other's certificates using
169 * a CA certificate. Setting this to false disables this behavior. (This is a
171 static bool verify_peer_cert = true;
173 /* Ordinarily, we require a CA certificate for the peer to be locally
174 * available. We can, however, bootstrap the CA certificate from the peer at
175 * the beginning of our first connection then use that certificate on all
176 * subsequent connections, saving it to a file for use in future runs also. In
177 * this case, 'bootstrap_ca_cert' is true. */
178 static bool bootstrap_ca_cert;
180 /* Session number. Used in debug logging messages to uniquely identify a
182 static unsigned int next_session_nr;
184 /* Who knows what can trigger various SSL errors, so let's throttle them down
186 static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(10, 25);
188 static int ssl_init(void);
189 static int do_ssl_init(void);
190 static bool ssl_wants_io(int ssl_error);
191 static void ssl_close(struct stream *);
192 static void ssl_clear_txbuf(struct ssl_stream *);
193 static void interpret_queued_ssl_error(const char *function);
194 static int interpret_ssl_error(const char *function, int ret, int error,
196 static DH *tmp_dh_callback(SSL *ssl, int is_export OVS_UNUSED, int keylength);
197 static void log_ca_cert(const char *file_name, X509 *cert);
198 static void stream_ssl_set_ca_cert_file__(const char *file_name,
200 static void ssl_protocol_cb(int write_p, int version, int content_type,
201 const void *, size_t, SSL *, void *sslv_);
204 want_to_poll_events(int want)
222 new_ssl_stream(const char *name, int fd, enum session_type type,
223 enum ssl_state state, const struct sockaddr_in *remote,
224 struct stream **streamp)
226 struct sockaddr_in local;
227 socklen_t local_len = sizeof local;
228 struct ssl_stream *sslv;
233 /* Check for all the needful configuration. */
235 if (!private_key.read) {
236 VLOG_ERR("Private key must be configured to use SSL");
237 retval = ENOPROTOOPT;
239 if (!certificate.read) {
240 VLOG_ERR("Certificate must be configured to use SSL");
241 retval = ENOPROTOOPT;
243 if (!ca_cert.read && verify_peer_cert && !bootstrap_ca_cert) {
244 VLOG_ERR("CA certificate must be configured to use SSL");
245 retval = ENOPROTOOPT;
247 if (!SSL_CTX_check_private_key(ctx)) {
248 VLOG_ERR("Private key does not match certificate public key: %s",
249 ERR_error_string(ERR_get_error(), NULL));
250 retval = ENOPROTOOPT;
256 /* Get the local IP and port information */
257 retval = getsockname(fd, (struct sockaddr *) &local, &local_len);
259 memset(&local, 0, sizeof local);
263 retval = setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &on, sizeof on);
265 VLOG_ERR("%s: setsockopt(TCP_NODELAY): %s", name, strerror(errno));
270 /* Create and configure OpenSSL stream. */
273 VLOG_ERR("SSL_new: %s", ERR_error_string(ERR_get_error(), NULL));
274 retval = ENOPROTOOPT;
277 if (SSL_set_fd(ssl, fd) == 0) {
278 VLOG_ERR("SSL_set_fd: %s", ERR_error_string(ERR_get_error(), NULL));
279 retval = ENOPROTOOPT;
282 if (!verify_peer_cert || (bootstrap_ca_cert && type == CLIENT)) {
283 SSL_set_verify(ssl, SSL_VERIFY_NONE, NULL);
285 if (type == CLIENT) {
286 /* Grab SSL session information from the cache. */
287 SSL_SESSION *session = shash_find_data(&client_sessions, name);
288 if (session && SSL_set_session(ssl, session) != 1) {
289 interpret_queued_ssl_error("SSL_set_session");
293 /* Create and return the ssl_stream. */
294 sslv = xmalloc(sizeof *sslv);
295 stream_init(&sslv->stream, &ssl_stream_class, EAGAIN, name);
296 stream_set_remote_ip(&sslv->stream, remote->sin_addr.s_addr);
297 stream_set_remote_port(&sslv->stream, remote->sin_port);
298 stream_set_local_ip(&sslv->stream, local.sin_addr.s_addr);
299 stream_set_local_port(&sslv->stream, local.sin_port);
305 sslv->rx_want = sslv->tx_want = SSL_NOTHING;
306 sslv->session_nr = next_session_nr++;
309 if (VLOG_IS_DBG_ENABLED()) {
310 SSL_set_msg_callback(ssl, ssl_protocol_cb);
311 SSL_set_msg_callback_arg(ssl, sslv);
314 *streamp = &sslv->stream;
325 static struct ssl_stream *
326 ssl_stream_cast(struct stream *stream)
328 stream_assert_class(stream, &ssl_stream_class);
329 return CONTAINER_OF(stream, struct ssl_stream, stream);
333 ssl_open(const char *name, char *suffix, struct stream **streamp)
335 struct sockaddr_in sin;
343 error = inet_open_active(SOCK_STREAM, suffix, OFP_SSL_PORT, &sin, &fd);
345 int state = error ? STATE_TCP_CONNECTING : STATE_SSL_CONNECTING;
346 return new_ssl_stream(name, fd, CLIENT, state, &sin, streamp);
348 VLOG_ERR("%s: connect: %s", name, strerror(error));
354 do_ca_cert_bootstrap(struct stream *stream)
356 struct ssl_stream *sslv = ssl_stream_cast(stream);
357 STACK_OF(X509) *chain;
363 chain = SSL_get_peer_cert_chain(sslv->ssl);
364 if (!chain || !sk_X509_num(chain)) {
365 VLOG_ERR("could not bootstrap CA cert: no certificate presented by "
369 cert = sk_X509_value(chain, sk_X509_num(chain) - 1);
371 /* Check that 'cert' is self-signed. Otherwise it is not a CA
372 * certificate and we should not attempt to use it as one. */
373 error = X509_check_issued(cert, cert);
375 VLOG_ERR("could not bootstrap CA cert: obtained certificate is "
376 "not self-signed (%s)",
377 X509_verify_cert_error_string(error));
378 if (sk_X509_num(chain) < 2) {
379 VLOG_ERR("only one certificate was received, so probably the peer "
380 "is not configured to send its CA certificate");
385 fd = open(ca_cert.file_name, O_CREAT | O_EXCL | O_WRONLY, 0444);
387 if (errno == EEXIST) {
388 VLOG_INFO("reading CA cert %s created by another process",
390 stream_ssl_set_ca_cert_file(ca_cert.file_name, true);
393 VLOG_ERR("could not bootstrap CA cert: creating %s failed: %s",
394 ca_cert.file_name, strerror(errno));
399 file = fdopen(fd, "w");
402 VLOG_ERR("could not bootstrap CA cert: fdopen failed: %s",
404 unlink(ca_cert.file_name);
408 if (!PEM_write_X509(file, cert)) {
409 VLOG_ERR("could not bootstrap CA cert: PEM_write_X509 to %s failed: "
410 "%s", ca_cert.file_name,
411 ERR_error_string(ERR_get_error(), NULL));
413 unlink(ca_cert.file_name);
419 VLOG_ERR("could not bootstrap CA cert: writing %s failed: %s",
420 ca_cert.file_name, strerror(error));
421 unlink(ca_cert.file_name);
425 VLOG_INFO("successfully bootstrapped CA cert to %s", ca_cert.file_name);
426 log_ca_cert(ca_cert.file_name, cert);
427 bootstrap_ca_cert = false;
430 /* SSL_CTX_add_client_CA makes a copy of cert's relevant data. */
431 SSL_CTX_add_client_CA(ctx, cert);
433 /* SSL_CTX_use_certificate() takes ownership of the certificate passed in.
434 * 'cert' is owned by sslv->ssl, so we need to duplicate it. */
435 cert = X509_dup(cert);
439 SSL_CTX_set_cert_store(ctx, X509_STORE_new());
440 if (SSL_CTX_load_verify_locations(ctx, ca_cert.file_name, NULL) != 1) {
441 VLOG_ERR("SSL_CTX_load_verify_locations: %s",
442 ERR_error_string(ERR_get_error(), NULL));
445 VLOG_INFO("killing successful connection to retry using CA cert");
450 ssl_delete_session(struct shash_node *node)
452 SSL_SESSION *session = node->data;
453 SSL_SESSION_free(session);
454 shash_delete(&client_sessions, node);
457 /* Find and free any previously cached session for 'stream''s target. */
459 ssl_flush_session(struct stream *stream)
461 struct shash_node *node;
463 node = shash_find(&client_sessions, stream_get_name(stream));
465 ssl_delete_session(node);
469 /* Add 'stream''s session to the cache for its target, so that it will be
470 * reused for future SSL connections to the same target. */
472 ssl_cache_session(struct stream *stream)
474 struct ssl_stream *sslv = ssl_stream_cast(stream);
475 SSL_SESSION *session;
477 /* Get session from stream. */
478 session = SSL_get1_session(sslv->ssl);
480 SSL_SESSION *old_session;
482 old_session = shash_replace(&client_sessions, stream_get_name(stream),
485 /* Free the session that we replaced. (We might actually have
486 * session == old_session, but either way we have to free it to
487 * avoid leaking a reference.) */
488 SSL_SESSION_free(old_session);
489 } else if (shash_count(&client_sessions) > MAX_CLIENT_SESSION_CACHE) {
491 struct shash_node *node = shash_random_node(&client_sessions);
492 if (node->data != session) {
493 ssl_delete_session(node);
502 ssl_connect(struct stream *stream)
504 struct ssl_stream *sslv = ssl_stream_cast(stream);
507 switch (sslv->state) {
508 case STATE_TCP_CONNECTING:
509 retval = check_connection_completion(sslv->fd);
513 sslv->state = STATE_SSL_CONNECTING;
516 case STATE_SSL_CONNECTING:
517 /* Capture the first few bytes of received data so that we can guess
518 * what kind of funny data we've been sent if SSL negotation fails. */
519 if (sslv->n_head <= 0) {
520 sslv->n_head = recv(sslv->fd, sslv->head, sizeof sslv->head,
524 retval = (sslv->type == CLIENT
525 ? SSL_connect(sslv->ssl) : SSL_accept(sslv->ssl));
527 int error = SSL_get_error(sslv->ssl, retval);
528 if (retval < 0 && ssl_wants_io(error)) {
533 if (sslv->type == CLIENT) {
534 /* Delete any cached session for this stream's target.
535 * Otherwise a single error causes recurring errors that
536 * don't resolve until the SSL client or server is
537 * restarted. (It can take dozens of reused connections to
538 * see this behavior, so this is difficult to test.) If we
539 * delete the session on the first error, though, the error
540 * only occurs once and then resolves itself. */
541 ssl_flush_session(stream);
544 interpret_ssl_error((sslv->type == CLIENT ? "SSL_connect"
545 : "SSL_accept"), retval, error, &unused);
546 shutdown(sslv->fd, SHUT_RDWR);
547 stream_report_content(sslv->head, sslv->n_head, STREAM_SSL,
548 THIS_MODULE, stream_get_name(stream));
551 } else if (bootstrap_ca_cert) {
552 return do_ca_cert_bootstrap(stream);
553 } else if (verify_peer_cert
554 && ((SSL_get_verify_mode(sslv->ssl)
555 & (SSL_VERIFY_NONE | SSL_VERIFY_PEER))
556 != SSL_VERIFY_PEER)) {
557 /* Two or more SSL connections completed at the same time while we
558 * were in bootstrap mode. Only one of these can finish the
559 * bootstrap successfully. The other one(s) must be rejected
560 * because they were not verified against the bootstrapped CA
561 * certificate. (Alternatively we could verify them against the CA
562 * certificate, but that's more trouble than it's worth. These
563 * connections will succeed the next time they retry, assuming that
564 * they have a certificate against the correct CA.) */
565 VLOG_ERR("rejecting SSL connection during bootstrap race window");
569 COVERAGE_INC(ssl_session);
570 if (SSL_session_reused(sslv->ssl)) {
571 COVERAGE_INC(ssl_session_reused);
581 ssl_close(struct stream *stream)
583 struct ssl_stream *sslv = ssl_stream_cast(stream);
584 ssl_clear_txbuf(sslv);
586 /* Attempt clean shutdown of the SSL connection. This will work most of
587 * the time, as long as the kernel send buffer has some free space and the
588 * SSL connection isn't renegotiating, etc. That has to be good enough,
589 * since we don't have any way to continue the close operation in the
591 SSL_shutdown(sslv->ssl);
593 ssl_cache_session(stream);
595 /* SSL_shutdown() might have signaled an error, in which case we need to
596 * flush it out of the OpenSSL error queue or the next OpenSSL operation
597 * will falsely signal an error. */
606 interpret_queued_ssl_error(const char *function)
608 int queued_error = ERR_get_error();
609 if (queued_error != 0) {
610 VLOG_WARN_RL(&rl, "%s: %s",
611 function, ERR_error_string(queued_error, NULL));
613 VLOG_ERR_RL(&rl, "%s: SSL_ERROR_SSL without queued error", function);
618 interpret_ssl_error(const char *function, int ret, int error,
625 VLOG_ERR_RL(&rl, "%s: unexpected SSL_ERROR_NONE", function);
628 case SSL_ERROR_ZERO_RETURN:
629 VLOG_ERR_RL(&rl, "%s: unexpected SSL_ERROR_ZERO_RETURN", function);
632 case SSL_ERROR_WANT_READ:
636 case SSL_ERROR_WANT_WRITE:
640 case SSL_ERROR_WANT_CONNECT:
641 VLOG_ERR_RL(&rl, "%s: unexpected SSL_ERROR_WANT_CONNECT", function);
644 case SSL_ERROR_WANT_ACCEPT:
645 VLOG_ERR_RL(&rl, "%s: unexpected SSL_ERROR_WANT_ACCEPT", function);
648 case SSL_ERROR_WANT_X509_LOOKUP:
649 VLOG_ERR_RL(&rl, "%s: unexpected SSL_ERROR_WANT_X509_LOOKUP",
653 case SSL_ERROR_SYSCALL: {
654 int queued_error = ERR_get_error();
655 if (queued_error == 0) {
658 VLOG_WARN_RL(&rl, "%s: system error (%s)",
659 function, strerror(status));
662 VLOG_WARN_RL(&rl, "%s: unexpected SSL connection close",
667 VLOG_WARN_RL(&rl, "%s: %s",
668 function, ERR_error_string(queued_error, NULL));
674 interpret_queued_ssl_error(function);
678 VLOG_ERR_RL(&rl, "%s: bad SSL error code %d", function, error);
685 ssl_recv(struct stream *stream, void *buffer, size_t n)
687 struct ssl_stream *sslv = ssl_stream_cast(stream);
691 /* Behavior of zero-byte SSL_read is poorly defined. */
694 old_state = SSL_get_state(sslv->ssl);
695 ret = SSL_read(sslv->ssl, buffer, n);
696 if (old_state != SSL_get_state(sslv->ssl)) {
697 sslv->tx_want = SSL_NOTHING;
699 sslv->rx_want = SSL_NOTHING;
704 int error = SSL_get_error(sslv->ssl, ret);
705 if (error == SSL_ERROR_ZERO_RETURN) {
708 return -interpret_ssl_error("SSL_read", ret, error,
715 ssl_clear_txbuf(struct ssl_stream *sslv)
717 ofpbuf_delete(sslv->txbuf);
722 ssl_do_tx(struct stream *stream)
724 struct ssl_stream *sslv = ssl_stream_cast(stream);
727 int old_state = SSL_get_state(sslv->ssl);
728 int ret = SSL_write(sslv->ssl, sslv->txbuf->data, sslv->txbuf->size);
729 if (old_state != SSL_get_state(sslv->ssl)) {
730 sslv->rx_want = SSL_NOTHING;
732 sslv->tx_want = SSL_NOTHING;
734 ofpbuf_pull(sslv->txbuf, ret);
735 if (sslv->txbuf->size == 0) {
739 int ssl_error = SSL_get_error(sslv->ssl, ret);
740 if (ssl_error == SSL_ERROR_ZERO_RETURN) {
741 VLOG_WARN_RL(&rl, "SSL_write: connection closed");
744 return interpret_ssl_error("SSL_write", ret, ssl_error,
752 ssl_send(struct stream *stream, const void *buffer, size_t n)
754 struct ssl_stream *sslv = ssl_stream_cast(stream);
761 sslv->txbuf = ofpbuf_clone_data(buffer, n);
762 error = ssl_do_tx(stream);
765 ssl_clear_txbuf(sslv);
768 leak_checker_claim(buffer);
778 ssl_run(struct stream *stream)
780 struct ssl_stream *sslv = ssl_stream_cast(stream);
782 if (sslv->txbuf && ssl_do_tx(stream) != EAGAIN) {
783 ssl_clear_txbuf(sslv);
788 ssl_run_wait(struct stream *stream)
790 struct ssl_stream *sslv = ssl_stream_cast(stream);
792 if (sslv->tx_want != SSL_NOTHING) {
793 poll_fd_wait(sslv->fd, want_to_poll_events(sslv->tx_want));
798 ssl_wait(struct stream *stream, enum stream_wait_type wait)
800 struct ssl_stream *sslv = ssl_stream_cast(stream);
804 if (stream_connect(stream) != EAGAIN) {
805 poll_immediate_wake();
807 switch (sslv->state) {
808 case STATE_TCP_CONNECTING:
809 poll_fd_wait(sslv->fd, POLLOUT);
812 case STATE_SSL_CONNECTING:
813 /* ssl_connect() called SSL_accept() or SSL_connect(), which
814 * set up the status that we test here. */
815 poll_fd_wait(sslv->fd,
816 want_to_poll_events(SSL_want(sslv->ssl)));
826 if (sslv->rx_want != SSL_NOTHING) {
827 poll_fd_wait(sslv->fd, want_to_poll_events(sslv->rx_want));
829 poll_immediate_wake();
835 /* We have room in our tx queue. */
836 poll_immediate_wake();
838 /* stream_run_wait() will do the right thing; don't bother with
848 struct stream_class ssl_stream_class = {
851 ssl_close, /* close */
852 ssl_connect, /* connect */
856 ssl_run_wait, /* run_wait */
864 struct pstream pstream;
868 struct pstream_class pssl_pstream_class;
870 static struct pssl_pstream *
871 pssl_pstream_cast(struct pstream *pstream)
873 pstream_assert_class(pstream, &pssl_pstream_class);
874 return CONTAINER_OF(pstream, struct pssl_pstream, pstream);
878 pssl_open(const char *name OVS_UNUSED, char *suffix, struct pstream **pstreamp)
880 struct pssl_pstream *pssl;
881 struct sockaddr_in sin;
882 char bound_name[128];
891 fd = inet_open_passive(SOCK_STREAM, suffix, OFP_SSL_PORT, &sin);
895 sprintf(bound_name, "pssl:%"PRIu16":"IP_FMT,
896 ntohs(sin.sin_port), IP_ARGS(&sin.sin_addr.s_addr));
898 pssl = xmalloc(sizeof *pssl);
899 pstream_init(&pssl->pstream, &pssl_pstream_class, bound_name);
901 *pstreamp = &pssl->pstream;
906 pssl_close(struct pstream *pstream)
908 struct pssl_pstream *pssl = pssl_pstream_cast(pstream);
914 pssl_accept(struct pstream *pstream, struct stream **new_streamp)
916 struct pssl_pstream *pssl = pssl_pstream_cast(pstream);
917 struct sockaddr_in sin;
918 socklen_t sin_len = sizeof sin;
923 new_fd = accept(pssl->fd, &sin, &sin_len);
926 if (error != EAGAIN) {
927 VLOG_DBG_RL(&rl, "accept: %s", strerror(error));
932 error = set_nonblocking(new_fd);
938 sprintf(name, "ssl:"IP_FMT, IP_ARGS(&sin.sin_addr));
939 if (sin.sin_port != htons(OFP_SSL_PORT)) {
940 sprintf(strchr(name, '\0'), ":%"PRIu16, ntohs(sin.sin_port));
942 return new_ssl_stream(name, new_fd, SERVER, STATE_SSL_CONNECTING, &sin,
947 pssl_wait(struct pstream *pstream)
949 struct pssl_pstream *pssl = pssl_pstream_cast(pstream);
950 poll_fd_wait(pssl->fd, POLLIN);
953 struct pstream_class pssl_pstream_class = {
962 * Returns true if OpenSSL error is WANT_READ or WANT_WRITE, indicating that
963 * OpenSSL is requesting that we call it back when the socket is ready for read
964 * or writing, respectively.
967 ssl_wants_io(int ssl_error)
969 return (ssl_error == SSL_ERROR_WANT_WRITE
970 || ssl_error == SSL_ERROR_WANT_READ);
976 static int init_status = -1;
977 if (init_status < 0) {
978 init_status = do_ssl_init();
979 assert(init_status >= 0);
990 SSL_load_error_strings();
992 /* New OpenSSL changed TLSv1_method() to return a "const" pointer, so the
993 * cast is needed to avoid a warning with those newer versions. */
994 method = (SSL_METHOD *) TLSv1_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,
1012 /* We have to set a session context ID string in 'ctx' because OpenSSL
1013 * otherwise refuses to use a cached session on the server side when
1014 * SSL_VERIFY_PEER is set. And it not only refuses to use the cached
1015 * session, it actually generates an error and kills the connection.
1016 * According to a comment in ssl_get_prev_session() in OpenSSL's
1017 * ssl/ssl_sess.c, this is intentional behavior.
1019 * Any context string is OK, as long as one is set. */
1020 SSL_CTX_set_session_id_context(ctx, (const unsigned char *) PACKAGE,
1027 tmp_dh_callback(SSL *ssl OVS_UNUSED, int is_export OVS_UNUSED, int keylength)
1032 DH *(*constructor)(void);
1035 static struct dh dh_table[] = {
1036 {1024, NULL, get_dh1024},
1037 {2048, NULL, get_dh2048},
1038 {4096, NULL, get_dh4096},
1043 for (dh = dh_table; dh < &dh_table[ARRAY_SIZE(dh_table)]; dh++) {
1044 if (dh->keylength == keylength) {
1046 dh->dh = dh->constructor();
1048 ovs_fatal(ENOMEM, "out of memory constructing "
1049 "Diffie-Hellman parameters");
1055 VLOG_ERR_RL(&rl, "no Diffie-Hellman parameters for key length %d",
1060 /* Returns true if SSL is at least partially configured. */
1062 stream_ssl_is_configured(void)
1064 return private_key.file_name || certificate.file_name || ca_cert.file_name;
1068 update_ssl_config(struct ssl_config_file *config, const char *file_name)
1070 struct timespec mtime;
1072 if (ssl_init() || !file_name) {
1076 /* If the file name hasn't changed and neither has the file contents, stop
1078 get_mtime(file_name, &mtime);
1079 if (config->file_name
1080 && !strcmp(config->file_name, file_name)
1081 && mtime.tv_sec == config->mtime.tv_sec
1082 && mtime.tv_nsec == config->mtime.tv_nsec) {
1086 /* Update 'config'. */
1087 config->mtime = mtime;
1088 if (file_name != config->file_name) {
1089 free(config->file_name);
1090 config->file_name = xstrdup(file_name);
1096 stream_ssl_set_private_key_file__(const char *file_name)
1098 if (SSL_CTX_use_PrivateKey_file(ctx, file_name, SSL_FILETYPE_PEM) == 1) {
1099 private_key.read = true;
1101 VLOG_ERR("SSL_use_PrivateKey_file: %s",
1102 ERR_error_string(ERR_get_error(), NULL));
1107 stream_ssl_set_private_key_file(const char *file_name)
1109 if (update_ssl_config(&private_key, file_name)) {
1110 stream_ssl_set_private_key_file__(file_name);
1115 stream_ssl_set_certificate_file__(const char *file_name)
1117 if (SSL_CTX_use_certificate_chain_file(ctx, file_name) == 1) {
1118 certificate.read = true;
1120 VLOG_ERR("SSL_use_certificate_file: %s",
1121 ERR_error_string(ERR_get_error(), NULL));
1126 stream_ssl_set_certificate_file(const char *file_name)
1128 if (update_ssl_config(&certificate, file_name)) {
1129 stream_ssl_set_certificate_file__(file_name);
1133 /* Sets the private key and certificate files in one operation. Use this
1134 * interface, instead of calling stream_ssl_set_private_key_file() and
1135 * stream_ssl_set_certificate_file() individually, in the main loop of a
1136 * long-running program whose key and certificate might change at runtime.
1138 * This is important because of OpenSSL's behavior. If an OpenSSL context
1139 * already has a certificate, and stream_ssl_set_private_key_file() is called
1140 * to install a new private key, OpenSSL will report an error because the new
1141 * private key does not match the old certificate. The other order, of setting
1142 * a new certificate, then setting a new private key, does work.
1144 * If this were the only problem, calling stream_ssl_set_certificate_file()
1145 * before stream_ssl_set_private_key_file() would fix it. But, if the private
1146 * key is changed before the certificate (e.g. someone "scp"s or "mv"s the new
1147 * private key in place before the certificate), then OpenSSL would reject that
1148 * change, and then the change of certificate would succeed, but there would be
1149 * no associated private key (because it had only changed once and therefore
1150 * there was no point in re-reading it).
1152 * This function avoids both problems by, whenever either the certificate or
1153 * the private key file changes, re-reading both of them, in the correct order.
1156 stream_ssl_set_key_and_cert(const char *private_key_file,
1157 const char *certificate_file)
1159 if (update_ssl_config(&private_key, private_key_file)
1160 || update_ssl_config(&certificate, certificate_file)) {
1161 stream_ssl_set_certificate_file__(certificate_file);
1162 stream_ssl_set_private_key_file__(private_key_file);
1166 /* Reads the X509 certificate or certificates in file 'file_name'. On success,
1167 * stores the address of the first element in an array of pointers to
1168 * certificates in '*certs' and the number of certificates in the array in
1169 * '*n_certs', and returns 0. On failure, stores a null pointer in '*certs', 0
1170 * in '*n_certs', and returns a positive errno value.
1172 * The caller is responsible for freeing '*certs'. */
1174 read_cert_file(const char *file_name, X509 ***certs, size_t *n_certs)
1177 size_t allocated_certs = 0;
1182 file = fopen(file_name, "r");
1184 VLOG_ERR("failed to open %s for reading: %s",
1185 file_name, strerror(errno));
1193 /* Read certificate from file. */
1194 certificate = PEM_read_X509(file, NULL, NULL, NULL);
1198 VLOG_ERR("PEM_read_X509 failed reading %s: %s",
1199 file_name, ERR_error_string(ERR_get_error(), NULL));
1200 for (i = 0; i < *n_certs; i++) {
1201 X509_free((*certs)[i]);
1209 /* Add certificate to array. */
1210 if (*n_certs >= allocated_certs) {
1211 *certs = x2nrealloc(*certs, &allocated_certs, sizeof **certs);
1213 (*certs)[(*n_certs)++] = certificate;
1215 /* Are there additional certificates in the file? */
1218 } while (isspace(c));
1229 /* Sets 'file_name' as the name of a file containing one or more X509
1230 * certificates to send to the peer. Typical use in OpenFlow is to send the CA
1231 * certificate to the peer, which enables a switch to pick up the controller's
1232 * CA certificate on its first connection. */
1234 stream_ssl_set_peer_ca_cert_file(const char *file_name)
1244 if (!read_cert_file(file_name, &certs, &n_certs)) {
1245 for (i = 0; i < n_certs; i++) {
1246 if (SSL_CTX_add_extra_chain_cert(ctx, certs[i]) != 1) {
1247 VLOG_ERR("SSL_CTX_add_extra_chain_cert: %s",
1248 ERR_error_string(ERR_get_error(), NULL));
1255 /* Logs fingerprint of CA certificate 'cert' obtained from 'file_name'. */
1257 log_ca_cert(const char *file_name, X509 *cert)
1259 unsigned char digest[EVP_MAX_MD_SIZE];
1260 unsigned int n_bytes;
1265 if (!X509_digest(cert, EVP_sha1(), digest, &n_bytes)) {
1266 ds_put_cstr(&fp, "<out of memory>");
1269 for (i = 0; i < n_bytes; i++) {
1271 ds_put_char(&fp, ':');
1273 ds_put_format(&fp, "%02hhx", digest[i]);
1276 subject = X509_NAME_oneline(X509_get_subject_name(cert), NULL, 0);
1277 VLOG_INFO("Trusting CA cert from %s (%s) (fingerprint %s)", file_name,
1278 subject ? subject : "<out of memory>", ds_cstr(&fp));
1279 OPENSSL_free(subject);
1284 stream_ssl_set_ca_cert_file__(const char *file_name, bool bootstrap)
1290 if (!strcmp(file_name, "none")) {
1291 verify_peer_cert = false;
1292 VLOG_WARN("Peer certificate validation disabled "
1293 "(this is a security risk)");
1294 } else if (bootstrap && stat(file_name, &s) && errno == ENOENT) {
1295 bootstrap_ca_cert = true;
1296 } else if (!read_cert_file(file_name, &certs, &n_certs)) {
1299 /* Set up list of CAs that the server will accept from the client. */
1300 for (i = 0; i < n_certs; i++) {
1301 /* SSL_CTX_add_client_CA makes a copy of the relevant data. */
1302 if (SSL_CTX_add_client_CA(ctx, certs[i]) != 1) {
1303 VLOG_ERR("failed to add client certificate %zu from %s: %s",
1305 ERR_error_string(ERR_get_error(), NULL));
1307 log_ca_cert(file_name, certs[i]);
1309 X509_free(certs[i]);
1313 /* Set up CAs for OpenSSL to trust in verifying the peer's
1315 SSL_CTX_set_cert_store(ctx, X509_STORE_new());
1316 if (SSL_CTX_load_verify_locations(ctx, file_name, NULL) != 1) {
1317 VLOG_ERR("SSL_CTX_load_verify_locations: %s",
1318 ERR_error_string(ERR_get_error(), NULL));
1322 bootstrap_ca_cert = false;
1324 ca_cert.read = true;
1327 /* Sets 'file_name' as the name of the file from which to read the CA
1328 * certificate used to verify the peer within SSL connections. If 'bootstrap'
1329 * is false, the file must exist. If 'bootstrap' is false, then the file is
1330 * read if it is exists; if it does not, then it will be created from the CA
1331 * certificate received from the peer on the first SSL connection. */
1333 stream_ssl_set_ca_cert_file(const char *file_name, bool bootstrap)
1335 if (!update_ssl_config(&ca_cert, file_name)) {
1339 stream_ssl_set_ca_cert_file__(file_name, bootstrap);
1342 /* SSL protocol logging. */
1345 ssl_alert_level_to_string(uint8_t type)
1348 case 1: return "warning";
1349 case 2: return "fatal";
1350 default: return "<unknown>";
1355 ssl_alert_description_to_string(uint8_t type)
1358 case 0: return "close_notify";
1359 case 10: return "unexpected_message";
1360 case 20: return "bad_record_mac";
1361 case 21: return "decryption_failed";
1362 case 22: return "record_overflow";
1363 case 30: return "decompression_failure";
1364 case 40: return "handshake_failure";
1365 case 42: return "bad_certificate";
1366 case 43: return "unsupported_certificate";
1367 case 44: return "certificate_revoked";
1368 case 45: return "certificate_expired";
1369 case 46: return "certificate_unknown";
1370 case 47: return "illegal_parameter";
1371 case 48: return "unknown_ca";
1372 case 49: return "access_denied";
1373 case 50: return "decode_error";
1374 case 51: return "decrypt_error";
1375 case 60: return "export_restriction";
1376 case 70: return "protocol_version";
1377 case 71: return "insufficient_security";
1378 case 80: return "internal_error";
1379 case 90: return "user_canceled";
1380 case 100: return "no_renegotiation";
1381 default: return "<unknown>";
1386 ssl_handshake_type_to_string(uint8_t type)
1389 case 0: return "hello_request";
1390 case 1: return "client_hello";
1391 case 2: return "server_hello";
1392 case 11: return "certificate";
1393 case 12: return "server_key_exchange";
1394 case 13: return "certificate_request";
1395 case 14: return "server_hello_done";
1396 case 15: return "certificate_verify";
1397 case 16: return "client_key_exchange";
1398 case 20: return "finished";
1399 default: return "<unknown>";
1404 ssl_protocol_cb(int write_p, int version OVS_UNUSED, int content_type,
1405 const void *buf_, size_t len, SSL *ssl OVS_UNUSED, void *sslv_)
1407 const struct ssl_stream *sslv = sslv_;
1408 const uint8_t *buf = buf_;
1411 if (!VLOG_IS_DBG_ENABLED()) {
1416 if (content_type == 20) {
1417 ds_put_cstr(&details, "change_cipher_spec");
1418 } else if (content_type == 21) {
1419 ds_put_format(&details, "alert: %s, %s",
1420 ssl_alert_level_to_string(buf[0]),
1421 ssl_alert_description_to_string(buf[1]));
1422 } else if (content_type == 22) {
1423 ds_put_format(&details, "handshake: %s",
1424 ssl_handshake_type_to_string(buf[0]));
1426 ds_put_format(&details, "type %d", content_type);
1429 VLOG_DBG("%s%u%s%s %s (%zu bytes)",
1430 sslv->type == CLIENT ? "client" : "server",
1431 sslv->session_nr, write_p ? "-->" : "<--",
1432 stream_get_name(&sslv->stream), ds_cstr(&details), len);
1434 ds_destroy(&details);