2 * Copyright (c) 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015 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"
48 #include "openvswitch/vlog.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 new_ssl_stream(const char *name
, int fd
, enum session_type type
,
223 enum ssl_state state
, struct stream
**streamp
)
225 struct ssl_stream
*sslv
;
229 /* Check for all the needful configuration. */
231 if (!private_key
.read
) {
232 VLOG_ERR("Private key must be configured to use SSL");
233 retval
= ENOPROTOOPT
;
235 if (!certificate
.read
) {
236 VLOG_ERR("Certificate must be configured to use SSL");
237 retval
= ENOPROTOOPT
;
239 if (!ca_cert
.read
&& verify_peer_cert
&& !bootstrap_ca_cert
) {
240 VLOG_ERR("CA certificate must be configured to use SSL");
241 retval
= ENOPROTOOPT
;
243 if (!retval
&& !SSL_CTX_check_private_key(ctx
)) {
244 VLOG_ERR("Private key does not match certificate public key: %s",
245 ERR_error_string(ERR_get_error(), NULL
));
246 retval
= ENOPROTOOPT
;
253 * On windows platforms, this can only be called upon TCP connected.
255 if (state
== STATE_SSL_CONNECTING
) {
256 setsockopt_tcp_nodelay(fd
);
259 /* Create and configure OpenSSL stream. */
262 VLOG_ERR("SSL_new: %s", ERR_error_string(ERR_get_error(), NULL
));
263 retval
= ENOPROTOOPT
;
266 if (SSL_set_fd(ssl
, fd
) == 0) {
267 VLOG_ERR("SSL_set_fd: %s", ERR_error_string(ERR_get_error(), NULL
));
268 retval
= ENOPROTOOPT
;
271 if (!verify_peer_cert
|| (bootstrap_ca_cert
&& type
== CLIENT
)) {
272 SSL_set_verify(ssl
, SSL_VERIFY_NONE
, NULL
);
275 /* Create and return the ssl_stream. */
276 sslv
= xmalloc(sizeof *sslv
);
277 stream_init(&sslv
->stream
, &ssl_stream_class
, EAGAIN
, name
);
283 sslv
->rx_want
= sslv
->tx_want
= SSL_NOTHING
;
284 sslv
->session_nr
= next_session_nr
++;
287 if (VLOG_IS_DBG_ENABLED()) {
288 SSL_set_msg_callback(ssl
, ssl_protocol_cb
);
289 SSL_set_msg_callback_arg(ssl
, sslv
);
292 *streamp
= &sslv
->stream
;
303 static struct ssl_stream
*
304 ssl_stream_cast(struct stream
*stream
)
306 stream_assert_class(stream
, &ssl_stream_class
);
307 return CONTAINER_OF(stream
, struct ssl_stream
, stream
);
311 ssl_open(const char *name
, char *suffix
, struct stream
**streamp
, uint8_t dscp
)
320 error
= inet_open_active(SOCK_STREAM
, suffix
, OFP_OLD_PORT
, NULL
, &fd
,
323 int state
= error
? STATE_TCP_CONNECTING
: STATE_SSL_CONNECTING
;
324 return new_ssl_stream(name
, fd
, CLIENT
, state
, streamp
);
326 VLOG_ERR("%s: connect: %s", name
, ovs_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
, ovs_strerror(errno
));
377 file
= fdopen(fd
, "w");
380 VLOG_ERR("could not bootstrap CA cert: fdopen failed: %s",
381 ovs_strerror(error
));
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
, ovs_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
;
440 setsockopt_tcp_nodelay(sslv
->fd
);
443 case STATE_SSL_CONNECTING
:
444 /* Capture the first few bytes of received data so that we can guess
445 * what kind of funny data we've been sent if SSL negotiation fails. */
446 if (sslv
->n_head
<= 0) {
447 sslv
->n_head
= recv(sslv
->fd
, sslv
->head
, sizeof sslv
->head
,
451 retval
= (sslv
->type
== CLIENT
452 ? SSL_connect(sslv
->ssl
) : SSL_accept(sslv
->ssl
));
454 int error
= SSL_get_error(sslv
->ssl
, retval
);
455 if (retval
< 0 && ssl_wants_io(error
)) {
460 interpret_ssl_error((sslv
->type
== CLIENT
? "SSL_connect"
461 : "SSL_accept"), retval
, error
, &unused
);
462 shutdown(sslv
->fd
, SHUT_RDWR
);
463 stream_report_content(sslv
->head
, sslv
->n_head
, STREAM_SSL
,
464 THIS_MODULE
, stream_get_name(stream
));
467 } else if (bootstrap_ca_cert
) {
468 return do_ca_cert_bootstrap(stream
);
469 } else if (verify_peer_cert
470 && ((SSL_get_verify_mode(sslv
->ssl
)
471 & (SSL_VERIFY_NONE
| SSL_VERIFY_PEER
))
472 != SSL_VERIFY_PEER
)) {
473 /* Two or more SSL connections completed at the same time while we
474 * were in bootstrap mode. Only one of these can finish the
475 * bootstrap successfully. The other one(s) must be rejected
476 * because they were not verified against the bootstrapped CA
477 * certificate. (Alternatively we could verify them against the CA
478 * certificate, but that's more trouble than it's worth. These
479 * connections will succeed the next time they retry, assuming that
480 * they have a certificate against the correct CA.) */
481 VLOG_INFO("rejecting SSL connection during bootstrap race window");
492 ssl_close(struct stream
*stream
)
494 struct ssl_stream
*sslv
= ssl_stream_cast(stream
);
495 ssl_clear_txbuf(sslv
);
497 /* Attempt clean shutdown of the SSL connection. This will work most of
498 * the time, as long as the kernel send buffer has some free space and the
499 * SSL connection isn't renegotiating, etc. That has to be good enough,
500 * since we don't have any way to continue the close operation in the
502 SSL_shutdown(sslv
->ssl
);
504 /* SSL_shutdown() might have signaled an error, in which case we need to
505 * flush it out of the OpenSSL error queue or the next OpenSSL operation
506 * will falsely signal an error. */
510 closesocket(sslv
->fd
);
515 interpret_queued_ssl_error(const char *function
)
517 int queued_error
= ERR_get_error();
518 if (queued_error
!= 0) {
519 VLOG_WARN_RL(&rl
, "%s: %s",
520 function
, ERR_error_string(queued_error
, NULL
));
522 VLOG_ERR_RL(&rl
, "%s: SSL_ERROR_SSL without queued error", function
);
527 interpret_ssl_error(const char *function
, int ret
, int error
,
534 VLOG_ERR_RL(&rl
, "%s: unexpected SSL_ERROR_NONE", function
);
537 case SSL_ERROR_ZERO_RETURN
:
538 VLOG_ERR_RL(&rl
, "%s: unexpected SSL_ERROR_ZERO_RETURN", function
);
541 case SSL_ERROR_WANT_READ
:
545 case SSL_ERROR_WANT_WRITE
:
549 case SSL_ERROR_WANT_CONNECT
:
550 VLOG_ERR_RL(&rl
, "%s: unexpected SSL_ERROR_WANT_CONNECT", function
);
553 case SSL_ERROR_WANT_ACCEPT
:
554 VLOG_ERR_RL(&rl
, "%s: unexpected SSL_ERROR_WANT_ACCEPT", function
);
557 case SSL_ERROR_WANT_X509_LOOKUP
:
558 VLOG_ERR_RL(&rl
, "%s: unexpected SSL_ERROR_WANT_X509_LOOKUP",
562 case SSL_ERROR_SYSCALL
: {
563 int queued_error
= ERR_get_error();
564 if (queued_error
== 0) {
567 VLOG_WARN_RL(&rl
, "%s: system error (%s)",
568 function
, ovs_strerror(status
));
571 VLOG_WARN_RL(&rl
, "%s: unexpected SSL connection close",
576 VLOG_WARN_RL(&rl
, "%s: %s",
577 function
, ERR_error_string(queued_error
, NULL
));
583 interpret_queued_ssl_error(function
);
587 VLOG_ERR_RL(&rl
, "%s: bad SSL error code %d", function
, error
);
594 ssl_recv(struct stream
*stream
, void *buffer
, size_t n
)
596 struct ssl_stream
*sslv
= ssl_stream_cast(stream
);
600 /* Behavior of zero-byte SSL_read is poorly defined. */
603 old_state
= SSL_get_state(sslv
->ssl
);
604 ret
= SSL_read(sslv
->ssl
, buffer
, n
);
605 if (old_state
!= SSL_get_state(sslv
->ssl
)) {
606 sslv
->tx_want
= SSL_NOTHING
;
608 sslv
->rx_want
= SSL_NOTHING
;
613 int error
= SSL_get_error(sslv
->ssl
, ret
);
614 if (error
== SSL_ERROR_ZERO_RETURN
) {
617 return -interpret_ssl_error("SSL_read", ret
, error
,
624 ssl_clear_txbuf(struct ssl_stream
*sslv
)
626 ofpbuf_delete(sslv
->txbuf
);
631 ssl_do_tx(struct stream
*stream
)
633 struct ssl_stream
*sslv
= ssl_stream_cast(stream
);
636 int old_state
= SSL_get_state(sslv
->ssl
);
637 int ret
= SSL_write(sslv
->ssl
,
638 ofpbuf_data(sslv
->txbuf
), ofpbuf_size(sslv
->txbuf
));
639 if (old_state
!= SSL_get_state(sslv
->ssl
)) {
640 sslv
->rx_want
= SSL_NOTHING
;
642 sslv
->tx_want
= SSL_NOTHING
;
644 ofpbuf_pull(sslv
->txbuf
, ret
);
645 if (ofpbuf_size(sslv
->txbuf
) == 0) {
649 int ssl_error
= SSL_get_error(sslv
->ssl
, ret
);
650 if (ssl_error
== SSL_ERROR_ZERO_RETURN
) {
651 VLOG_WARN_RL(&rl
, "SSL_write: connection closed");
654 return interpret_ssl_error("SSL_write", ret
, ssl_error
,
662 ssl_send(struct stream
*stream
, const void *buffer
, size_t n
)
664 struct ssl_stream
*sslv
= ssl_stream_cast(stream
);
671 sslv
->txbuf
= ofpbuf_clone_data(buffer
, n
);
672 error
= ssl_do_tx(stream
);
675 ssl_clear_txbuf(sslv
);
687 ssl_run(struct stream
*stream
)
689 struct ssl_stream
*sslv
= ssl_stream_cast(stream
);
691 if (sslv
->txbuf
&& ssl_do_tx(stream
) != EAGAIN
) {
692 ssl_clear_txbuf(sslv
);
697 ssl_run_wait(struct stream
*stream
)
699 struct ssl_stream
*sslv
= ssl_stream_cast(stream
);
701 if (sslv
->tx_want
!= SSL_NOTHING
) {
702 poll_fd_wait(sslv
->fd
, want_to_poll_events(sslv
->tx_want
));
707 ssl_wait(struct stream
*stream
, enum stream_wait_type wait
)
709 struct ssl_stream
*sslv
= ssl_stream_cast(stream
);
713 if (stream_connect(stream
) != EAGAIN
) {
714 poll_immediate_wake();
716 switch (sslv
->state
) {
717 case STATE_TCP_CONNECTING
:
718 poll_fd_wait(sslv
->fd
, POLLOUT
);
721 case STATE_SSL_CONNECTING
:
722 /* ssl_connect() called SSL_accept() or SSL_connect(), which
723 * set up the status that we test here. */
724 poll_fd_wait(sslv
->fd
,
725 want_to_poll_events(SSL_want(sslv
->ssl
)));
735 if (sslv
->rx_want
!= SSL_NOTHING
) {
736 poll_fd_wait(sslv
->fd
, want_to_poll_events(sslv
->rx_want
));
738 poll_immediate_wake();
744 /* We have room in our tx queue. */
745 poll_immediate_wake();
747 /* stream_run_wait() will do the right thing; don't bother with
757 const struct stream_class ssl_stream_class
= {
759 true, /* needs_probes */
761 ssl_close
, /* close */
762 ssl_connect
, /* connect */
766 ssl_run_wait
, /* run_wait */
774 struct pstream pstream
;
778 const struct pstream_class pssl_pstream_class
;
780 static struct pssl_pstream
*
781 pssl_pstream_cast(struct pstream
*pstream
)
783 pstream_assert_class(pstream
, &pssl_pstream_class
);
784 return CONTAINER_OF(pstream
, struct pssl_pstream
, pstream
);
788 pssl_open(const char *name OVS_UNUSED
, char *suffix
, struct pstream
**pstreamp
,
791 char bound_name
[SS_NTOP_BUFSIZE
+ 16];
792 char addrbuf
[SS_NTOP_BUFSIZE
];
793 struct sockaddr_storage ss
;
794 struct pssl_pstream
*pssl
;
804 fd
= inet_open_passive(SOCK_STREAM
, suffix
, OFP_OLD_PORT
, &ss
, dscp
, true);
809 port
= ss_get_port(&ss
);
810 snprintf(bound_name
, sizeof bound_name
, "ptcp:%"PRIu16
":%s",
811 port
, ss_format_address(&ss
, addrbuf
, sizeof addrbuf
));
813 pssl
= xmalloc(sizeof *pssl
);
814 pstream_init(&pssl
->pstream
, &pssl_pstream_class
, bound_name
);
815 pstream_set_bound_port(&pssl
->pstream
, htons(port
));
817 *pstreamp
= &pssl
->pstream
;
822 pssl_close(struct pstream
*pstream
)
824 struct pssl_pstream
*pssl
= pssl_pstream_cast(pstream
);
825 closesocket(pssl
->fd
);
830 pssl_accept(struct pstream
*pstream
, struct stream
**new_streamp
)
832 struct pssl_pstream
*pssl
= pssl_pstream_cast(pstream
);
833 char name
[SS_NTOP_BUFSIZE
+ 16];
834 char addrbuf
[SS_NTOP_BUFSIZE
];
835 struct sockaddr_storage ss
;
836 socklen_t ss_len
= sizeof ss
;
840 new_fd
= accept(pssl
->fd
, (struct sockaddr
*) &ss
, &ss_len
);
842 error
= sock_errno();
844 if (error
== WSAEWOULDBLOCK
) {
848 if (error
!= EAGAIN
) {
849 VLOG_DBG_RL(&rl
, "accept: %s", sock_strerror(error
));
854 error
= set_nonblocking(new_fd
);
860 snprintf(name
, sizeof name
, "tcp:%s:%"PRIu16
,
861 ss_format_address(&ss
, addrbuf
, sizeof addrbuf
),
863 return new_ssl_stream(name
, new_fd
, SERVER
, STATE_SSL_CONNECTING
,
868 pssl_wait(struct pstream
*pstream
)
870 struct pssl_pstream
*pssl
= pssl_pstream_cast(pstream
);
871 poll_fd_wait(pssl
->fd
, POLLIN
);
874 const struct pstream_class pssl_pstream_class
= {
884 * Returns true if OpenSSL error is WANT_READ or WANT_WRITE, indicating that
885 * OpenSSL is requesting that we call it back when the socket is ready for read
886 * or writing, respectively.
889 ssl_wants_io(int ssl_error
)
891 return (ssl_error
== SSL_ERROR_WANT_WRITE
892 || ssl_error
== SSL_ERROR_WANT_READ
);
898 static int init_status
= -1;
899 if (init_status
< 0) {
900 init_status
= do_ssl_init();
901 ovs_assert(init_status
>= 0);
912 /* The following call is needed if we "#include <openssl/applink.c>". */
913 CRYPTO_malloc_init();
916 SSL_load_error_strings();
918 if (!RAND_status()) {
919 /* We occasionally see OpenSSL fail to seed its random number generator
920 * in heavily loaded hypervisors. I suspect the following scenario:
922 * 1. OpenSSL calls read() to get 32 bytes from /dev/urandom.
923 * 2. The kernel generates 10 bytes of randomness and copies it out.
924 * 3. A signal arrives (perhaps SIGALRM).
925 * 4. The kernel interrupts the system call to service the signal.
926 * 5. Userspace gets 10 bytes of entropy.
927 * 6. OpenSSL doesn't read again to get the final 22 bytes. Therefore
928 * OpenSSL doesn't have enough entropy to consider itself
931 * The only part I'm not entirely sure about is #6, because the OpenSSL
932 * code is so hard to read. */
936 VLOG_WARN("OpenSSL random seeding failed, reseeding ourselves");
938 retval
= get_entropy(seed
, sizeof seed
);
940 VLOG_ERR("failed to obtain entropy (%s)",
941 ovs_retval_to_string(retval
));
942 return retval
> 0 ? retval
: ENOPROTOOPT
;
945 RAND_seed(seed
, sizeof seed
);
948 /* OpenSSL has a bunch of "connection methods": SSLv2_method(),
949 * SSLv3_method(), TLSv1_method(), SSLv23_method(), ... Most of these
950 * support exactly one version of SSL, e.g. TLSv1_method() supports TLSv1
951 * only, not any earlier *or later* version. The only exception is
952 * SSLv23_method(), which in fact supports *any* version of SSL and TLS.
953 * We don't want SSLv2 or SSLv3 support, so we turn it off below with
954 * SSL_CTX_set_options().
956 * The cast is needed to avoid a warning with newer versions of OpenSSL in
957 * which SSLv23_method() returns a "const" pointer. */
958 method
= CONST_CAST(SSL_METHOD
*, SSLv23_method());
959 if (method
== NULL
) {
960 VLOG_ERR("TLSv1_method: %s", ERR_error_string(ERR_get_error(), NULL
));
964 ctx
= SSL_CTX_new(method
);
966 VLOG_ERR("SSL_CTX_new: %s", ERR_error_string(ERR_get_error(), NULL
));
969 SSL_CTX_set_options(ctx
, SSL_OP_NO_SSLv2
| SSL_OP_NO_SSLv3
);
970 SSL_CTX_set_tmp_dh_callback(ctx
, tmp_dh_callback
);
971 SSL_CTX_set_mode(ctx
, SSL_MODE_ENABLE_PARTIAL_WRITE
);
972 SSL_CTX_set_mode(ctx
, SSL_MODE_ACCEPT_MOVING_WRITE_BUFFER
);
973 SSL_CTX_set_verify(ctx
, SSL_VERIFY_PEER
| SSL_VERIFY_FAIL_IF_NO_PEER_CERT
,
980 tmp_dh_callback(SSL
*ssl OVS_UNUSED
, int is_export OVS_UNUSED
, int keylength
)
985 DH
*(*constructor
)(void);
988 static struct dh dh_table
[] = {
989 {1024, NULL
, get_dh1024
},
990 {2048, NULL
, get_dh2048
},
991 {4096, NULL
, get_dh4096
},
996 for (dh
= dh_table
; dh
< &dh_table
[ARRAY_SIZE(dh_table
)]; dh
++) {
997 if (dh
->keylength
== keylength
) {
999 dh
->dh
= dh
->constructor();
1007 VLOG_ERR_RL(&rl
, "no Diffie-Hellman parameters for key length %d",
1012 /* Returns true if SSL is at least partially configured. */
1014 stream_ssl_is_configured(void)
1016 return private_key
.file_name
|| certificate
.file_name
|| ca_cert
.file_name
;
1020 update_ssl_config(struct ssl_config_file
*config
, const char *file_name
)
1022 struct timespec mtime
;
1025 if (ssl_init() || !file_name
) {
1029 /* If the file name hasn't changed and neither has the file contents, stop
1031 error
= get_mtime(file_name
, &mtime
);
1032 if (error
&& error
!= ENOENT
) {
1033 VLOG_ERR_RL(&rl
, "%s: stat failed (%s)",
1034 file_name
, ovs_strerror(error
));
1036 if (config
->file_name
1037 && !strcmp(config
->file_name
, file_name
)
1038 && mtime
.tv_sec
== config
->mtime
.tv_sec
1039 && mtime
.tv_nsec
== config
->mtime
.tv_nsec
) {
1043 /* Update 'config'. */
1044 config
->mtime
= mtime
;
1045 if (file_name
!= config
->file_name
) {
1046 free(config
->file_name
);
1047 config
->file_name
= xstrdup(file_name
);
1053 stream_ssl_set_private_key_file__(const char *file_name
)
1055 if (SSL_CTX_use_PrivateKey_file(ctx
, file_name
, SSL_FILETYPE_PEM
) == 1) {
1056 private_key
.read
= true;
1058 VLOG_ERR("SSL_use_PrivateKey_file: %s",
1059 ERR_error_string(ERR_get_error(), NULL
));
1064 stream_ssl_set_private_key_file(const char *file_name
)
1066 if (update_ssl_config(&private_key
, file_name
)) {
1067 stream_ssl_set_private_key_file__(file_name
);
1072 stream_ssl_set_certificate_file__(const char *file_name
)
1074 if (SSL_CTX_use_certificate_chain_file(ctx
, file_name
) == 1) {
1075 certificate
.read
= true;
1077 VLOG_ERR("SSL_use_certificate_file: %s",
1078 ERR_error_string(ERR_get_error(), NULL
));
1083 stream_ssl_set_certificate_file(const char *file_name
)
1085 if (update_ssl_config(&certificate
, file_name
)) {
1086 stream_ssl_set_certificate_file__(file_name
);
1090 /* Sets the private key and certificate files in one operation. Use this
1091 * interface, instead of calling stream_ssl_set_private_key_file() and
1092 * stream_ssl_set_certificate_file() individually, in the main loop of a
1093 * long-running program whose key and certificate might change at runtime.
1095 * This is important because of OpenSSL's behavior. If an OpenSSL context
1096 * already has a certificate, and stream_ssl_set_private_key_file() is called
1097 * to install a new private key, OpenSSL will report an error because the new
1098 * private key does not match the old certificate. The other order, of setting
1099 * a new certificate, then setting a new private key, does work.
1101 * If this were the only problem, calling stream_ssl_set_certificate_file()
1102 * before stream_ssl_set_private_key_file() would fix it. But, if the private
1103 * key is changed before the certificate (e.g. someone "scp"s or "mv"s the new
1104 * private key in place before the certificate), then OpenSSL would reject that
1105 * change, and then the change of certificate would succeed, but there would be
1106 * no associated private key (because it had only changed once and therefore
1107 * there was no point in re-reading it).
1109 * This function avoids both problems by, whenever either the certificate or
1110 * the private key file changes, re-reading both of them, in the correct order.
1113 stream_ssl_set_key_and_cert(const char *private_key_file
,
1114 const char *certificate_file
)
1116 if (update_ssl_config(&private_key
, private_key_file
)
1117 || update_ssl_config(&certificate
, certificate_file
)) {
1118 stream_ssl_set_certificate_file__(certificate_file
);
1119 stream_ssl_set_private_key_file__(private_key_file
);
1123 /* Reads the X509 certificate or certificates in file 'file_name'. On success,
1124 * stores the address of the first element in an array of pointers to
1125 * certificates in '*certs' and the number of certificates in the array in
1126 * '*n_certs', and returns 0. On failure, stores a null pointer in '*certs', 0
1127 * in '*n_certs', and returns a positive errno value.
1129 * The caller is responsible for freeing '*certs'. */
1131 read_cert_file(const char *file_name
, X509
***certs
, size_t *n_certs
)
1134 size_t allocated_certs
= 0;
1139 file
= fopen(file_name
, "r");
1141 VLOG_ERR("failed to open %s for reading: %s",
1142 file_name
, ovs_strerror(errno
));
1150 /* Read certificate from file. */
1151 certificate
= PEM_read_X509(file
, NULL
, NULL
, NULL
);
1155 VLOG_ERR("PEM_read_X509 failed reading %s: %s",
1156 file_name
, ERR_error_string(ERR_get_error(), NULL
));
1157 for (i
= 0; i
< *n_certs
; i
++) {
1158 X509_free((*certs
)[i
]);
1167 /* Add certificate to array. */
1168 if (*n_certs
>= allocated_certs
) {
1169 *certs
= x2nrealloc(*certs
, &allocated_certs
, sizeof **certs
);
1171 (*certs
)[(*n_certs
)++] = certificate
;
1173 /* Are there additional certificates in the file? */
1176 } while (isspace(c
));
1187 /* Sets 'file_name' as the name of a file containing one or more X509
1188 * certificates to send to the peer. Typical use in OpenFlow is to send the CA
1189 * certificate to the peer, which enables a switch to pick up the controller's
1190 * CA certificate on its first connection. */
1192 stream_ssl_set_peer_ca_cert_file(const char *file_name
)
1202 if (!read_cert_file(file_name
, &certs
, &n_certs
)) {
1203 for (i
= 0; i
< n_certs
; i
++) {
1204 if (SSL_CTX_add_extra_chain_cert(ctx
, certs
[i
]) != 1) {
1205 VLOG_ERR("SSL_CTX_add_extra_chain_cert: %s",
1206 ERR_error_string(ERR_get_error(), NULL
));
1213 /* Logs fingerprint of CA certificate 'cert' obtained from 'file_name'. */
1215 log_ca_cert(const char *file_name
, X509
*cert
)
1217 unsigned char digest
[EVP_MAX_MD_SIZE
];
1218 unsigned int n_bytes
;
1223 if (!X509_digest(cert
, EVP_sha1(), digest
, &n_bytes
)) {
1224 ds_put_cstr(&fp
, "<out of memory>");
1227 for (i
= 0; i
< n_bytes
; i
++) {
1229 ds_put_char(&fp
, ':');
1231 ds_put_format(&fp
, "%02x", digest
[i
]);
1234 subject
= X509_NAME_oneline(X509_get_subject_name(cert
), NULL
, 0);
1235 VLOG_INFO("Trusting CA cert from %s (%s) (fingerprint %s)", file_name
,
1236 subject
? subject
: "<out of memory>", ds_cstr(&fp
));
1237 OPENSSL_free(subject
);
1242 stream_ssl_set_ca_cert_file__(const char *file_name
,
1243 bool bootstrap
, bool force
)
1249 if (!update_ssl_config(&ca_cert
, file_name
) && !force
) {
1253 if (!strcmp(file_name
, "none")) {
1254 verify_peer_cert
= false;
1255 VLOG_WARN("Peer certificate validation disabled "
1256 "(this is a security risk)");
1257 } else if (bootstrap
&& stat(file_name
, &s
) && errno
== ENOENT
) {
1258 bootstrap_ca_cert
= true;
1259 } else if (!read_cert_file(file_name
, &certs
, &n_certs
)) {
1262 /* Set up list of CAs that the server will accept from the client. */
1263 for (i
= 0; i
< n_certs
; i
++) {
1264 /* SSL_CTX_add_client_CA makes a copy of the relevant data. */
1265 if (SSL_CTX_add_client_CA(ctx
, certs
[i
]) != 1) {
1266 VLOG_ERR("failed to add client certificate %"PRIuSIZE
" from %s: %s",
1268 ERR_error_string(ERR_get_error(), NULL
));
1270 log_ca_cert(file_name
, certs
[i
]);
1272 X509_free(certs
[i
]);
1276 /* Set up CAs for OpenSSL to trust in verifying the peer's
1278 SSL_CTX_set_cert_store(ctx
, X509_STORE_new());
1279 if (SSL_CTX_load_verify_locations(ctx
, file_name
, NULL
) != 1) {
1280 VLOG_ERR("SSL_CTX_load_verify_locations: %s",
1281 ERR_error_string(ERR_get_error(), NULL
));
1285 bootstrap_ca_cert
= false;
1287 ca_cert
.read
= true;
1290 /* Sets 'file_name' as the name of the file from which to read the CA
1291 * certificate used to verify the peer within SSL connections. If 'bootstrap'
1292 * is false, the file must exist. If 'bootstrap' is false, then the file is
1293 * read if it is exists; if it does not, then it will be created from the CA
1294 * certificate received from the peer on the first SSL connection. */
1296 stream_ssl_set_ca_cert_file(const char *file_name
, bool bootstrap
)
1298 stream_ssl_set_ca_cert_file__(file_name
, bootstrap
, false);
1301 /* SSL protocol logging. */
1304 ssl_alert_level_to_string(uint8_t type
)
1307 case 1: return "warning";
1308 case 2: return "fatal";
1309 default: return "<unknown>";
1314 ssl_alert_description_to_string(uint8_t type
)
1317 case 0: return "close_notify";
1318 case 10: return "unexpected_message";
1319 case 20: return "bad_record_mac";
1320 case 21: return "decryption_failed";
1321 case 22: return "record_overflow";
1322 case 30: return "decompression_failure";
1323 case 40: return "handshake_failure";
1324 case 42: return "bad_certificate";
1325 case 43: return "unsupported_certificate";
1326 case 44: return "certificate_revoked";
1327 case 45: return "certificate_expired";
1328 case 46: return "certificate_unknown";
1329 case 47: return "illegal_parameter";
1330 case 48: return "unknown_ca";
1331 case 49: return "access_denied";
1332 case 50: return "decode_error";
1333 case 51: return "decrypt_error";
1334 case 60: return "export_restriction";
1335 case 70: return "protocol_version";
1336 case 71: return "insufficient_security";
1337 case 80: return "internal_error";
1338 case 90: return "user_canceled";
1339 case 100: return "no_renegotiation";
1340 default: return "<unknown>";
1345 ssl_handshake_type_to_string(uint8_t type
)
1348 case 0: return "hello_request";
1349 case 1: return "client_hello";
1350 case 2: return "server_hello";
1351 case 11: return "certificate";
1352 case 12: return "server_key_exchange";
1353 case 13: return "certificate_request";
1354 case 14: return "server_hello_done";
1355 case 15: return "certificate_verify";
1356 case 16: return "client_key_exchange";
1357 case 20: return "finished";
1358 default: return "<unknown>";
1363 ssl_protocol_cb(int write_p
, int version OVS_UNUSED
, int content_type
,
1364 const void *buf_
, size_t len
, SSL
*ssl OVS_UNUSED
, void *sslv_
)
1366 const struct ssl_stream
*sslv
= sslv_
;
1367 const uint8_t *buf
= buf_
;
1370 if (!VLOG_IS_DBG_ENABLED()) {
1375 if (content_type
== 20) {
1376 ds_put_cstr(&details
, "change_cipher_spec");
1377 } else if (content_type
== 21) {
1378 ds_put_format(&details
, "alert: %s, %s",
1379 ssl_alert_level_to_string(buf
[0]),
1380 ssl_alert_description_to_string(buf
[1]));
1381 } else if (content_type
== 22) {
1382 ds_put_format(&details
, "handshake: %s",
1383 ssl_handshake_type_to_string(buf
[0]));
1385 ds_put_format(&details
, "type %d", content_type
);
1388 VLOG_DBG("%s%u%s%s %s (%"PRIuSIZE
" bytes)",
1389 sslv
->type
== CLIENT
? "client" : "server",
1390 sslv
->session_nr
, write_p
? "-->" : "<--",
1391 stream_get_name(&sslv
->stream
), ds_cstr(&details
), len
);
1393 ds_destroy(&details
);