2 * Copyright (c) 2008, 2009, 2010, 2011, 2012, 2013 Nicira, Inc.
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at:
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
18 #include "stream-ssl.h"
24 #include <sys/types.h>
25 #include <sys/socket.h>
26 #include <netinet/tcp.h>
27 #include <openssl/err.h>
28 #include <openssl/rand.h>
29 #include <openssl/ssl.h>
30 #include <openssl/x509v3.h>
32 #include <sys/fcntl.h>
36 #include "dynamic-string.h"
38 #include "leak-checker.h"
40 #include "openflow/openflow.h"
42 #include "poll-loop.h"
44 #include "socket-util.h"
46 #include "stream-provider.h"
51 VLOG_DEFINE_THIS_MODULE(stream_ssl
);
69 enum session_type type
;
73 unsigned int session_nr
;
75 /* rx_want and tx_want record the result of the last call to SSL_read()
76 * and SSL_write(), respectively:
78 * - If the call reported that data needed to be read from the file
79 * descriptor, the corresponding member is set to SSL_READING.
81 * - If the call reported that data needed to be written to the file
82 * descriptor, the corresponding member is set to SSL_WRITING.
84 * - Otherwise, the member is set to SSL_NOTHING, indicating that the
85 * call completed successfully (or with an error) and that there is no
88 * These are needed because there is no way to ask OpenSSL what a data read
89 * or write would require without giving it a buffer to receive into or
90 * data to send, respectively. (Note that the SSL_want() status is
91 * overwritten by each SSL_read() or SSL_write() call, so we can't rely on
94 * A single call to SSL_read() or SSL_write() can perform both reading
95 * and writing and thus invalidate not one of these values but actually
96 * both. Consider this situation, for example:
98 * - SSL_write() blocks on a read, so tx_want gets SSL_READING.
100 * - SSL_read() laters succeeds reading from 'fd' and clears out the
101 * whole receive buffer, so rx_want gets SSL_READING.
103 * - Client calls stream_wait(STREAM_RECV) and stream_wait(STREAM_SEND)
106 * - Now we're stuck blocking until the peer sends us data, even though
107 * SSL_write() could now succeed, which could easily be a deadlock
110 * On the other hand, we can't reset both tx_want and rx_want on every call
111 * to SSL_read() or SSL_write(), because that would produce livelock,
112 * e.g. in this situation:
114 * - SSL_write() blocks, so tx_want gets SSL_READING or SSL_WRITING.
116 * - SSL_read() blocks, so rx_want gets SSL_READING or SSL_WRITING,
117 * but tx_want gets reset to SSL_NOTHING.
119 * - Client calls stream_wait(STREAM_RECV) and stream_wait(STREAM_SEND)
122 * - Client wakes up immediately since SSL_NOTHING in tx_want indicates
123 * that no blocking is necessary.
125 * The solution we adopt here is to set tx_want to SSL_NOTHING after
126 * calling SSL_read() only if the SSL state of the connection changed,
127 * which indicates that an SSL-level renegotiation made some progress, and
128 * similarly for rx_want and SSL_write(). This prevents both the
129 * deadlock and livelock situations above.
131 int rx_want
, tx_want
;
133 /* A few bytes of header data in case SSL negotiation fails. */
138 /* SSL context created by ssl_init(). */
141 struct ssl_config_file
{
142 bool read
; /* Whether the file was successfully read. */
143 char *file_name
; /* Configured file name, if any. */
144 struct timespec mtime
; /* File mtime as of last time we read it. */
147 /* SSL configuration files. */
148 static struct ssl_config_file private_key
;
149 static struct ssl_config_file certificate
;
150 static struct ssl_config_file ca_cert
;
152 /* Ordinarily, the SSL client and server verify each other's certificates using
153 * a CA certificate. Setting this to false disables this behavior. (This is a
155 static bool verify_peer_cert
= true;
157 /* Ordinarily, we require a CA certificate for the peer to be locally
158 * available. We can, however, bootstrap the CA certificate from the peer at
159 * the beginning of our first connection then use that certificate on all
160 * subsequent connections, saving it to a file for use in future runs also. In
161 * this case, 'bootstrap_ca_cert' is true. */
162 static bool bootstrap_ca_cert
;
164 /* Session number. Used in debug logging messages to uniquely identify a
166 static unsigned int next_session_nr
;
168 /* Who knows what can trigger various SSL errors, so let's throttle them down
170 static struct vlog_rate_limit rl
= VLOG_RATE_LIMIT_INIT(10, 25);
172 static int ssl_init(void);
173 static int do_ssl_init(void);
174 static bool ssl_wants_io(int ssl_error
);
175 static void ssl_close(struct stream
*);
176 static void ssl_clear_txbuf(struct ssl_stream
*);
177 static void interpret_queued_ssl_error(const char *function
);
178 static int interpret_ssl_error(const char *function
, int ret
, int error
,
180 static DH
*tmp_dh_callback(SSL
*ssl
, int is_export OVS_UNUSED
, int keylength
);
181 static void log_ca_cert(const char *file_name
, X509
*cert
);
182 static void stream_ssl_set_ca_cert_file__(const char *file_name
,
183 bool bootstrap
, bool force
);
184 static void ssl_protocol_cb(int write_p
, int version
, int content_type
,
185 const void *, size_t, SSL
*, void *sslv_
);
186 static bool update_ssl_config(struct ssl_config_file
*, const char *file_name
);
189 want_to_poll_events(int want
)
207 new_ssl_stream(const char *name
, int fd
, enum session_type type
,
208 enum ssl_state state
, const struct sockaddr_in
*remote
,
209 struct stream
**streamp
)
211 struct sockaddr_in local
;
212 socklen_t local_len
= sizeof local
;
213 struct ssl_stream
*sslv
;
218 /* Check for all the needful configuration. */
220 if (!private_key
.read
) {
221 VLOG_ERR("Private key must be configured to use SSL");
222 retval
= ENOPROTOOPT
;
224 if (!certificate
.read
) {
225 VLOG_ERR("Certificate must be configured to use SSL");
226 retval
= ENOPROTOOPT
;
228 if (!ca_cert
.read
&& verify_peer_cert
&& !bootstrap_ca_cert
) {
229 VLOG_ERR("CA certificate must be configured to use SSL");
230 retval
= ENOPROTOOPT
;
232 if (!retval
&& !SSL_CTX_check_private_key(ctx
)) {
233 VLOG_ERR("Private key does not match certificate public key: %s",
234 ERR_error_string(ERR_get_error(), NULL
));
235 retval
= ENOPROTOOPT
;
241 /* Get the local IP and port information */
242 retval
= getsockname(fd
, (struct sockaddr
*) &local
, &local_len
);
244 memset(&local
, 0, sizeof local
);
248 retval
= setsockopt(fd
, IPPROTO_TCP
, TCP_NODELAY
, &on
, sizeof on
);
250 VLOG_ERR("%s: setsockopt(TCP_NODELAY): %s", name
, strerror(errno
));
255 /* Create and configure OpenSSL stream. */
258 VLOG_ERR("SSL_new: %s", ERR_error_string(ERR_get_error(), NULL
));
259 retval
= ENOPROTOOPT
;
262 if (SSL_set_fd(ssl
, fd
) == 0) {
263 VLOG_ERR("SSL_set_fd: %s", ERR_error_string(ERR_get_error(), NULL
));
264 retval
= ENOPROTOOPT
;
267 if (!verify_peer_cert
|| (bootstrap_ca_cert
&& type
== CLIENT
)) {
268 SSL_set_verify(ssl
, SSL_VERIFY_NONE
, NULL
);
271 /* Create and return the ssl_stream. */
272 sslv
= xmalloc(sizeof *sslv
);
273 stream_init(&sslv
->stream
, &ssl_stream_class
, EAGAIN
, name
);
274 stream_set_remote_ip(&sslv
->stream
, remote
->sin_addr
.s_addr
);
275 stream_set_remote_port(&sslv
->stream
, remote
->sin_port
);
276 stream_set_local_ip(&sslv
->stream
, local
.sin_addr
.s_addr
);
277 stream_set_local_port(&sslv
->stream
, local
.sin_port
);
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
)
313 struct sockaddr_in sin
;
321 error
= inet_open_active(SOCK_STREAM
, suffix
, OFP_SSL_PORT
, &sin
, &fd
,
324 int state
= error
? STATE_TCP_CONNECTING
: STATE_SSL_CONNECTING
;
325 return new_ssl_stream(name
, fd
, CLIENT
, state
, &sin
, streamp
);
327 VLOG_ERR("%s: connect: %s", name
, strerror(error
));
333 do_ca_cert_bootstrap(struct stream
*stream
)
335 struct ssl_stream
*sslv
= ssl_stream_cast(stream
);
336 STACK_OF(X509
) *chain
;
342 chain
= SSL_get_peer_cert_chain(sslv
->ssl
);
343 if (!chain
|| !sk_X509_num(chain
)) {
344 VLOG_ERR("could not bootstrap CA cert: no certificate presented by "
348 cert
= sk_X509_value(chain
, sk_X509_num(chain
) - 1);
350 /* Check that 'cert' is self-signed. Otherwise it is not a CA
351 * certificate and we should not attempt to use it as one. */
352 error
= X509_check_issued(cert
, cert
);
354 VLOG_ERR("could not bootstrap CA cert: obtained certificate is "
355 "not self-signed (%s)",
356 X509_verify_cert_error_string(error
));
357 if (sk_X509_num(chain
) < 2) {
358 VLOG_ERR("only one certificate was received, so probably the peer "
359 "is not configured to send its CA certificate");
364 fd
= open(ca_cert
.file_name
, O_CREAT
| O_EXCL
| O_WRONLY
, 0444);
366 if (errno
== EEXIST
) {
367 VLOG_INFO_RL(&rl
, "reading CA cert %s created by another process",
369 stream_ssl_set_ca_cert_file__(ca_cert
.file_name
, true, true);
372 VLOG_ERR("could not bootstrap CA cert: creating %s failed: %s",
373 ca_cert
.file_name
, strerror(errno
));
378 file
= fdopen(fd
, "w");
381 VLOG_ERR("could not bootstrap CA cert: fdopen failed: %s",
383 unlink(ca_cert
.file_name
);
387 if (!PEM_write_X509(file
, cert
)) {
388 VLOG_ERR("could not bootstrap CA cert: PEM_write_X509 to %s failed: "
389 "%s", ca_cert
.file_name
,
390 ERR_error_string(ERR_get_error(), NULL
));
392 unlink(ca_cert
.file_name
);
398 VLOG_ERR("could not bootstrap CA cert: writing %s failed: %s",
399 ca_cert
.file_name
, strerror(error
));
400 unlink(ca_cert
.file_name
);
404 VLOG_INFO("successfully bootstrapped CA cert to %s", ca_cert
.file_name
);
405 log_ca_cert(ca_cert
.file_name
, cert
);
406 bootstrap_ca_cert
= false;
409 /* SSL_CTX_add_client_CA makes a copy of cert's relevant data. */
410 SSL_CTX_add_client_CA(ctx
, cert
);
412 /* SSL_CTX_use_certificate() takes ownership of the certificate passed in.
413 * 'cert' is owned by sslv->ssl, so we need to duplicate it. */
414 cert
= X509_dup(cert
);
418 SSL_CTX_set_cert_store(ctx
, X509_STORE_new());
419 if (SSL_CTX_load_verify_locations(ctx
, ca_cert
.file_name
, NULL
) != 1) {
420 VLOG_ERR("SSL_CTX_load_verify_locations: %s",
421 ERR_error_string(ERR_get_error(), NULL
));
424 VLOG_INFO("killing successful connection to retry using CA cert");
429 ssl_connect(struct stream
*stream
)
431 struct ssl_stream
*sslv
= ssl_stream_cast(stream
);
434 switch (sslv
->state
) {
435 case STATE_TCP_CONNECTING
:
436 retval
= check_connection_completion(sslv
->fd
);
440 sslv
->state
= STATE_SSL_CONNECTING
;
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 negotation 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. */
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
, 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
, sslv
->txbuf
->data
, sslv
->txbuf
->size
);
638 if (old_state
!= SSL_get_state(sslv
->ssl
)) {
639 sslv
->rx_want
= SSL_NOTHING
;
641 sslv
->tx_want
= SSL_NOTHING
;
643 ofpbuf_pull(sslv
->txbuf
, ret
);
644 if (sslv
->txbuf
->size
== 0) {
648 int ssl_error
= SSL_get_error(sslv
->ssl
, ret
);
649 if (ssl_error
== SSL_ERROR_ZERO_RETURN
) {
650 VLOG_WARN_RL(&rl
, "SSL_write: connection closed");
653 return interpret_ssl_error("SSL_write", ret
, ssl_error
,
661 ssl_send(struct stream
*stream
, const void *buffer
, size_t n
)
663 struct ssl_stream
*sslv
= ssl_stream_cast(stream
);
670 sslv
->txbuf
= ofpbuf_clone_data(buffer
, n
);
671 error
= ssl_do_tx(stream
);
674 ssl_clear_txbuf(sslv
);
677 leak_checker_claim(buffer
);
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 struct pssl_pstream
*pssl
;
792 struct sockaddr_in sin
;
793 char bound_name
[128];
802 fd
= inet_open_passive(SOCK_STREAM
, suffix
, OFP_SSL_PORT
, &sin
, dscp
);
806 sprintf(bound_name
, "pssl:%"PRIu16
":"IP_FMT
,
807 ntohs(sin
.sin_port
), IP_ARGS(sin
.sin_addr
.s_addr
));
809 pssl
= xmalloc(sizeof *pssl
);
810 pstream_init(&pssl
->pstream
, &pssl_pstream_class
, bound_name
);
811 pstream_set_bound_port(&pssl
->pstream
, sin
.sin_port
);
813 *pstreamp
= &pssl
->pstream
;
818 pssl_close(struct pstream
*pstream
)
820 struct pssl_pstream
*pssl
= pssl_pstream_cast(pstream
);
826 pssl_accept(struct pstream
*pstream
, struct stream
**new_streamp
)
828 struct pssl_pstream
*pssl
= pssl_pstream_cast(pstream
);
829 struct sockaddr_in sin
;
830 socklen_t sin_len
= sizeof sin
;
835 new_fd
= accept(pssl
->fd
, (struct sockaddr
*) &sin
, &sin_len
);
838 if (error
!= EAGAIN
) {
839 VLOG_DBG_RL(&rl
, "accept: %s", strerror(error
));
844 error
= set_nonblocking(new_fd
);
850 sprintf(name
, "ssl:"IP_FMT
, IP_ARGS(sin
.sin_addr
.s_addr
));
851 if (sin
.sin_port
!= htons(OFP_SSL_PORT
)) {
852 sprintf(strchr(name
, '\0'), ":%"PRIu16
, ntohs(sin
.sin_port
));
854 return new_ssl_stream(name
, new_fd
, SERVER
, STATE_SSL_CONNECTING
, &sin
,
859 pssl_wait(struct pstream
*pstream
)
861 struct pssl_pstream
*pssl
= pssl_pstream_cast(pstream
);
862 poll_fd_wait(pssl
->fd
, POLLIN
);
866 pssl_set_dscp(struct pstream
*pstream
, uint8_t dscp
)
868 struct pssl_pstream
*pssl
= pssl_pstream_cast(pstream
);
869 return set_dscp(pssl
->fd
, dscp
);
872 const struct pstream_class pssl_pstream_class
= {
883 * Returns true if OpenSSL error is WANT_READ or WANT_WRITE, indicating that
884 * OpenSSL is requesting that we call it back when the socket is ready for read
885 * or writing, respectively.
888 ssl_wants_io(int ssl_error
)
890 return (ssl_error
== SSL_ERROR_WANT_WRITE
891 || ssl_error
== SSL_ERROR_WANT_READ
);
897 static int init_status
= -1;
898 if (init_status
< 0) {
899 init_status
= do_ssl_init();
900 ovs_assert(init_status
>= 0);
911 SSL_load_error_strings();
913 if (!RAND_status()) {
914 /* We occasionally see OpenSSL fail to seed its random number generator
915 * in heavily loaded hypervisors. I suspect the following scenario:
917 * 1. OpenSSL calls read() to get 32 bytes from /dev/urandom.
918 * 2. The kernel generates 10 bytes of randomness and copies it out.
919 * 3. A signal arrives (perhaps SIGALRM).
920 * 4. The kernel interrupts the system call to service the signal.
921 * 5. Userspace gets 10 bytes of entropy.
922 * 6. OpenSSL doesn't read again to get the final 22 bytes. Therefore
923 * OpenSSL doesn't have enough entropy to consider itself
926 * The only part I'm not entirely sure about is #6, because the OpenSSL
927 * code is so hard to read. */
931 VLOG_WARN("OpenSSL random seeding failed, reseeding ourselves");
933 retval
= get_entropy(seed
, sizeof seed
);
935 VLOG_ERR("failed to obtain entropy (%s)",
936 ovs_retval_to_string(retval
));
937 return retval
> 0 ? retval
: ENOPROTOOPT
;
940 RAND_seed(seed
, sizeof seed
);
943 /* New OpenSSL changed TLSv1_method() to return a "const" pointer, so the
944 * cast is needed to avoid a warning with those newer versions. */
945 method
= CONST_CAST(SSL_METHOD
*, TLSv1_method());
946 if (method
== NULL
) {
947 VLOG_ERR("TLSv1_method: %s", ERR_error_string(ERR_get_error(), NULL
));
951 ctx
= SSL_CTX_new(method
);
953 VLOG_ERR("SSL_CTX_new: %s", ERR_error_string(ERR_get_error(), NULL
));
956 SSL_CTX_set_options(ctx
, SSL_OP_NO_SSLv2
| SSL_OP_NO_SSLv3
);
957 SSL_CTX_set_tmp_dh_callback(ctx
, tmp_dh_callback
);
958 SSL_CTX_set_mode(ctx
, SSL_MODE_ENABLE_PARTIAL_WRITE
);
959 SSL_CTX_set_mode(ctx
, SSL_MODE_ACCEPT_MOVING_WRITE_BUFFER
);
960 SSL_CTX_set_verify(ctx
, SSL_VERIFY_PEER
| SSL_VERIFY_FAIL_IF_NO_PEER_CERT
,
967 tmp_dh_callback(SSL
*ssl OVS_UNUSED
, int is_export OVS_UNUSED
, int keylength
)
972 DH
*(*constructor
)(void);
975 static struct dh dh_table
[] = {
976 {1024, NULL
, get_dh1024
},
977 {2048, NULL
, get_dh2048
},
978 {4096, NULL
, get_dh4096
},
983 for (dh
= dh_table
; dh
< &dh_table
[ARRAY_SIZE(dh_table
)]; dh
++) {
984 if (dh
->keylength
== keylength
) {
986 dh
->dh
= dh
->constructor();
994 VLOG_ERR_RL(&rl
, "no Diffie-Hellman parameters for key length %d",
999 /* Returns true if SSL is at least partially configured. */
1001 stream_ssl_is_configured(void)
1003 return private_key
.file_name
|| certificate
.file_name
|| ca_cert
.file_name
;
1007 update_ssl_config(struct ssl_config_file
*config
, const char *file_name
)
1009 struct timespec mtime
;
1012 if (ssl_init() || !file_name
) {
1016 /* If the file name hasn't changed and neither has the file contents, stop
1018 error
= get_mtime(file_name
, &mtime
);
1019 if (error
&& error
!= ENOENT
) {
1020 VLOG_ERR_RL(&rl
, "%s: stat failed (%s)", file_name
, strerror(error
));
1022 if (config
->file_name
1023 && !strcmp(config
->file_name
, file_name
)
1024 && mtime
.tv_sec
== config
->mtime
.tv_sec
1025 && mtime
.tv_nsec
== config
->mtime
.tv_nsec
) {
1029 /* Update 'config'. */
1030 config
->mtime
= mtime
;
1031 if (file_name
!= config
->file_name
) {
1032 free(config
->file_name
);
1033 config
->file_name
= xstrdup(file_name
);
1039 stream_ssl_set_private_key_file__(const char *file_name
)
1041 if (SSL_CTX_use_PrivateKey_file(ctx
, file_name
, SSL_FILETYPE_PEM
) == 1) {
1042 private_key
.read
= true;
1044 VLOG_ERR("SSL_use_PrivateKey_file: %s",
1045 ERR_error_string(ERR_get_error(), NULL
));
1050 stream_ssl_set_private_key_file(const char *file_name
)
1052 if (update_ssl_config(&private_key
, file_name
)) {
1053 stream_ssl_set_private_key_file__(file_name
);
1058 stream_ssl_set_certificate_file__(const char *file_name
)
1060 if (SSL_CTX_use_certificate_chain_file(ctx
, file_name
) == 1) {
1061 certificate
.read
= true;
1063 VLOG_ERR("SSL_use_certificate_file: %s",
1064 ERR_error_string(ERR_get_error(), NULL
));
1069 stream_ssl_set_certificate_file(const char *file_name
)
1071 if (update_ssl_config(&certificate
, file_name
)) {
1072 stream_ssl_set_certificate_file__(file_name
);
1076 /* Sets the private key and certificate files in one operation. Use this
1077 * interface, instead of calling stream_ssl_set_private_key_file() and
1078 * stream_ssl_set_certificate_file() individually, in the main loop of a
1079 * long-running program whose key and certificate might change at runtime.
1081 * This is important because of OpenSSL's behavior. If an OpenSSL context
1082 * already has a certificate, and stream_ssl_set_private_key_file() is called
1083 * to install a new private key, OpenSSL will report an error because the new
1084 * private key does not match the old certificate. The other order, of setting
1085 * a new certificate, then setting a new private key, does work.
1087 * If this were the only problem, calling stream_ssl_set_certificate_file()
1088 * before stream_ssl_set_private_key_file() would fix it. But, if the private
1089 * key is changed before the certificate (e.g. someone "scp"s or "mv"s the new
1090 * private key in place before the certificate), then OpenSSL would reject that
1091 * change, and then the change of certificate would succeed, but there would be
1092 * no associated private key (because it had only changed once and therefore
1093 * there was no point in re-reading it).
1095 * This function avoids both problems by, whenever either the certificate or
1096 * the private key file changes, re-reading both of them, in the correct order.
1099 stream_ssl_set_key_and_cert(const char *private_key_file
,
1100 const char *certificate_file
)
1102 if (update_ssl_config(&private_key
, private_key_file
)
1103 || update_ssl_config(&certificate
, certificate_file
)) {
1104 stream_ssl_set_certificate_file__(certificate_file
);
1105 stream_ssl_set_private_key_file__(private_key_file
);
1109 /* Reads the X509 certificate or certificates in file 'file_name'. On success,
1110 * stores the address of the first element in an array of pointers to
1111 * certificates in '*certs' and the number of certificates in the array in
1112 * '*n_certs', and returns 0. On failure, stores a null pointer in '*certs', 0
1113 * in '*n_certs', and returns a positive errno value.
1115 * The caller is responsible for freeing '*certs'. */
1117 read_cert_file(const char *file_name
, X509
***certs
, size_t *n_certs
)
1120 size_t allocated_certs
= 0;
1125 file
= fopen(file_name
, "r");
1127 VLOG_ERR("failed to open %s for reading: %s",
1128 file_name
, strerror(errno
));
1136 /* Read certificate from file. */
1137 certificate
= PEM_read_X509(file
, NULL
, NULL
, NULL
);
1141 VLOG_ERR("PEM_read_X509 failed reading %s: %s",
1142 file_name
, ERR_error_string(ERR_get_error(), NULL
));
1143 for (i
= 0; i
< *n_certs
; i
++) {
1144 X509_free((*certs
)[i
]);
1152 /* Add certificate to array. */
1153 if (*n_certs
>= allocated_certs
) {
1154 *certs
= x2nrealloc(*certs
, &allocated_certs
, sizeof **certs
);
1156 (*certs
)[(*n_certs
)++] = certificate
;
1158 /* Are there additional certificates in the file? */
1161 } while (isspace(c
));
1172 /* Sets 'file_name' as the name of a file containing one or more X509
1173 * certificates to send to the peer. Typical use in OpenFlow is to send the CA
1174 * certificate to the peer, which enables a switch to pick up the controller's
1175 * CA certificate on its first connection. */
1177 stream_ssl_set_peer_ca_cert_file(const char *file_name
)
1187 if (!read_cert_file(file_name
, &certs
, &n_certs
)) {
1188 for (i
= 0; i
< n_certs
; i
++) {
1189 if (SSL_CTX_add_extra_chain_cert(ctx
, certs
[i
]) != 1) {
1190 VLOG_ERR("SSL_CTX_add_extra_chain_cert: %s",
1191 ERR_error_string(ERR_get_error(), NULL
));
1198 /* Logs fingerprint of CA certificate 'cert' obtained from 'file_name'. */
1200 log_ca_cert(const char *file_name
, X509
*cert
)
1202 unsigned char digest
[EVP_MAX_MD_SIZE
];
1203 unsigned int n_bytes
;
1208 if (!X509_digest(cert
, EVP_sha1(), digest
, &n_bytes
)) {
1209 ds_put_cstr(&fp
, "<out of memory>");
1212 for (i
= 0; i
< n_bytes
; i
++) {
1214 ds_put_char(&fp
, ':');
1216 ds_put_format(&fp
, "%02hhx", digest
[i
]);
1219 subject
= X509_NAME_oneline(X509_get_subject_name(cert
), NULL
, 0);
1220 VLOG_INFO("Trusting CA cert from %s (%s) (fingerprint %s)", file_name
,
1221 subject
? subject
: "<out of memory>", ds_cstr(&fp
));
1222 OPENSSL_free(subject
);
1227 stream_ssl_set_ca_cert_file__(const char *file_name
,
1228 bool bootstrap
, bool force
)
1234 if (!update_ssl_config(&ca_cert
, file_name
) && !force
) {
1238 if (!strcmp(file_name
, "none")) {
1239 verify_peer_cert
= false;
1240 VLOG_WARN("Peer certificate validation disabled "
1241 "(this is a security risk)");
1242 } else if (bootstrap
&& stat(file_name
, &s
) && errno
== ENOENT
) {
1243 bootstrap_ca_cert
= true;
1244 } else if (!read_cert_file(file_name
, &certs
, &n_certs
)) {
1247 /* Set up list of CAs that the server will accept from the client. */
1248 for (i
= 0; i
< n_certs
; i
++) {
1249 /* SSL_CTX_add_client_CA makes a copy of the relevant data. */
1250 if (SSL_CTX_add_client_CA(ctx
, certs
[i
]) != 1) {
1251 VLOG_ERR("failed to add client certificate %zu from %s: %s",
1253 ERR_error_string(ERR_get_error(), NULL
));
1255 log_ca_cert(file_name
, certs
[i
]);
1257 X509_free(certs
[i
]);
1261 /* Set up CAs for OpenSSL to trust in verifying the peer's
1263 SSL_CTX_set_cert_store(ctx
, X509_STORE_new());
1264 if (SSL_CTX_load_verify_locations(ctx
, file_name
, NULL
) != 1) {
1265 VLOG_ERR("SSL_CTX_load_verify_locations: %s",
1266 ERR_error_string(ERR_get_error(), NULL
));
1270 bootstrap_ca_cert
= false;
1272 ca_cert
.read
= true;
1275 /* Sets 'file_name' as the name of the file from which to read the CA
1276 * certificate used to verify the peer within SSL connections. If 'bootstrap'
1277 * is false, the file must exist. If 'bootstrap' is false, then the file is
1278 * read if it is exists; if it does not, then it will be created from the CA
1279 * certificate received from the peer on the first SSL connection. */
1281 stream_ssl_set_ca_cert_file(const char *file_name
, bool bootstrap
)
1283 stream_ssl_set_ca_cert_file__(file_name
, bootstrap
, false);
1286 /* SSL protocol logging. */
1289 ssl_alert_level_to_string(uint8_t type
)
1292 case 1: return "warning";
1293 case 2: return "fatal";
1294 default: return "<unknown>";
1299 ssl_alert_description_to_string(uint8_t type
)
1302 case 0: return "close_notify";
1303 case 10: return "unexpected_message";
1304 case 20: return "bad_record_mac";
1305 case 21: return "decryption_failed";
1306 case 22: return "record_overflow";
1307 case 30: return "decompression_failure";
1308 case 40: return "handshake_failure";
1309 case 42: return "bad_certificate";
1310 case 43: return "unsupported_certificate";
1311 case 44: return "certificate_revoked";
1312 case 45: return "certificate_expired";
1313 case 46: return "certificate_unknown";
1314 case 47: return "illegal_parameter";
1315 case 48: return "unknown_ca";
1316 case 49: return "access_denied";
1317 case 50: return "decode_error";
1318 case 51: return "decrypt_error";
1319 case 60: return "export_restriction";
1320 case 70: return "protocol_version";
1321 case 71: return "insufficient_security";
1322 case 80: return "internal_error";
1323 case 90: return "user_canceled";
1324 case 100: return "no_renegotiation";
1325 default: return "<unknown>";
1330 ssl_handshake_type_to_string(uint8_t type
)
1333 case 0: return "hello_request";
1334 case 1: return "client_hello";
1335 case 2: return "server_hello";
1336 case 11: return "certificate";
1337 case 12: return "server_key_exchange";
1338 case 13: return "certificate_request";
1339 case 14: return "server_hello_done";
1340 case 15: return "certificate_verify";
1341 case 16: return "client_key_exchange";
1342 case 20: return "finished";
1343 default: return "<unknown>";
1348 ssl_protocol_cb(int write_p
, int version OVS_UNUSED
, int content_type
,
1349 const void *buf_
, size_t len
, SSL
*ssl OVS_UNUSED
, void *sslv_
)
1351 const struct ssl_stream
*sslv
= sslv_
;
1352 const uint8_t *buf
= buf_
;
1355 if (!VLOG_IS_DBG_ENABLED()) {
1360 if (content_type
== 20) {
1361 ds_put_cstr(&details
, "change_cipher_spec");
1362 } else if (content_type
== 21) {
1363 ds_put_format(&details
, "alert: %s, %s",
1364 ssl_alert_level_to_string(buf
[0]),
1365 ssl_alert_description_to_string(buf
[1]));
1366 } else if (content_type
== 22) {
1367 ds_put_format(&details
, "handshake: %s",
1368 ssl_handshake_type_to_string(buf
[0]));
1370 ds_put_format(&details
, "type %d", content_type
);
1373 VLOG_DBG("%s%u%s%s %s (%zu bytes)",
1374 sslv
->type
== CLIENT
? "client" : "server",
1375 sslv
->session_nr
, write_p
? "-->" : "<--",
1376 stream_get_name(&sslv
->stream
), ds_cstr(&details
), len
);
1378 ds_destroy(&details
);