1 /* Copyright (c) 2008 The Board of Trustees of The Leland Stanford
4 * We are making the OpenFlow specification and associated documentation
5 * (Software) available for public use and benefit with the expectation
6 * that others will use, modify and enhance the Software and contribute
7 * those enhancements back to the community. However, since we would
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9 * restrictions as possible permission is hereby granted, free of
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11 * the Software under the copyrights without restriction, including
12 * without limitation the rights to use, copy, modify, merge, publish,
13 * distribute, sublicense, and/or sell copies of the Software, and to
14 * permit persons to whom the Software is furnished to do so, subject to
15 * the following conditions:
17 * The above copyright notice and this permission notice shall be
18 * included in all copies or substantial portions of the Software.
20 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
21 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
22 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
23 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
24 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
25 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
26 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
29 * The name and trademarks of copyright holder(s) may NOT be used in
30 * advertising or publicity pertaining to the Software or any
31 * derivatives without specific, written prior permission.
35 #include "vconn-ssl.h"
41 #include <netinet/tcp.h>
42 #include <openssl/err.h>
43 #include <openssl/ssl.h>
47 #include "socket-util.h"
51 #include "poll-loop.h"
52 #include "ofp-print.h"
53 #include "socket-util.h"
55 #include "vconn-provider.h"
58 #define THIS_MODULE VLM_vconn_ssl
77 enum session_type type;
82 struct poll_waiter *tx_waiter;
84 /* rx_want and tx_want record the result of the last call to SSL_read()
85 * and SSL_write(), respectively:
87 * - If the call reported that data needed to be read from the file
88 * descriptor, the corresponding member is set to SSL_READING.
90 * - If the call reported that data needed to be written to the file
91 * descriptor, the corresponding member is set to SSL_WRITING.
93 * - Otherwise, the member is set to SSL_NOTHING, indicating that the
94 * call completed successfully (or with an error) and that there is no
97 * These are needed because there is no way to ask OpenSSL what a data read
98 * or write would require without giving it a buffer to receive into or
99 * data to send, respectively. (Note that the SSL_want() status is
100 * overwritten by each SSL_read() or SSL_write() call, so we can't rely on
103 * A single call to SSL_read() or SSL_write() can perform both reading
104 * and writing and thus invalidate not one of these values but actually
105 * both. Consider this situation, for example:
107 * - SSL_write() blocks on a read, so tx_want gets SSL_READING.
109 * - SSL_read() laters succeeds reading from 'fd' and clears out the
110 * whole receive buffer, so rx_want gets SSL_READING.
112 * - Client calls vconn_wait(WAIT_RECV) and vconn_wait(WAIT_SEND) and
115 * - Now we're stuck blocking until the peer sends us data, even though
116 * SSL_write() could now succeed, which could easily be a deadlock
119 * On the other hand, we can't reset both tx_want and rx_want on every call
120 * to SSL_read() or SSL_write(), because that would produce livelock,
121 * e.g. in this situation:
123 * - SSL_write() blocks, so tx_want gets SSL_READING or SSL_WRITING.
125 * - SSL_read() blocks, so rx_want gets SSL_READING or SSL_WRITING,
126 * but tx_want gets reset to SSL_NOTHING.
128 * - Client calls vconn_wait(WAIT_RECV) and vconn_wait(WAIT_SEND) and
131 * - Client wakes up immediately since SSL_NOTHING in tx_want indicates
132 * that no blocking is necessary.
134 * The solution we adopt here is to set tx_want to SSL_NOTHING after
135 * calling SSL_read() only if the SSL state of the connection changed,
136 * which indicates that an SSL-level renegotiation made some progress, and
137 * similarly for rx_want and SSL_write(). This prevents both the
138 * deadlock and livelock situations above.
140 int rx_want, tx_want;
143 /* SSL context created by ssl_init(). */
146 /* Required configuration. */
147 static bool has_private_key, has_certificate, has_ca_cert;
149 /* Who knows what can trigger various SSL errors, so let's throttle them down
151 static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(10, 25);
153 static int ssl_init(void);
154 static int do_ssl_init(void);
155 static bool ssl_wants_io(int ssl_error);
156 static void ssl_close(struct vconn *);
157 static int interpret_ssl_error(const char *function, int ret, int error,
159 static void ssl_tx_poll_callback(int fd, short int revents, void *vconn_);
160 static DH *tmp_dh_callback(SSL *ssl, int is_export UNUSED, int keylength);
163 want_to_poll_events(int want)
181 new_ssl_vconn(const char *name, int fd, enum session_type type,
182 enum ssl_state state, const struct sockaddr_in *sin,
183 struct vconn **vconnp)
185 struct ssl_vconn *sslv;
190 /* Check for all the needful configuration. */
191 if (!has_private_key) {
192 VLOG_ERR("Private key must be configured to use SSL");
195 if (!has_certificate) {
196 VLOG_ERR("Certificate must be configured to use SSL");
200 VLOG_ERR("CA certificate must be configured to use SSL");
203 if (!SSL_CTX_check_private_key(ctx)) {
204 VLOG_ERR("Private key does not match certificate public key");
209 retval = setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &on, sizeof on);
211 VLOG_ERR("%s: setsockopt(TCP_NODELAY): %s", name, strerror(errno));
216 /* Create and configure OpenSSL stream. */
219 VLOG_ERR("SSL_new: %s", ERR_error_string(ERR_get_error(), NULL));
223 if (SSL_set_fd(ssl, fd) == 0) {
224 VLOG_ERR("SSL_set_fd: %s", ERR_error_string(ERR_get_error(), NULL));
228 /* Create and return the ssl_vconn. */
229 sslv = xmalloc(sizeof *sslv);
230 vconn_init(&sslv->vconn, &ssl_vconn_class, EAGAIN, sin->sin_addr.s_addr,
238 sslv->tx_waiter = NULL;
239 sslv->rx_want = sslv->tx_want = SSL_NOTHING;
240 *vconnp = &sslv->vconn;
251 static struct ssl_vconn *
252 ssl_vconn_cast(struct vconn *vconn)
254 vconn_assert_class(vconn, &ssl_vconn_class);
255 return CONTAINER_OF(vconn, struct ssl_vconn, vconn);
259 ssl_open(const char *name, char *suffix, struct vconn **vconnp)
261 char *save_ptr, *host_name, *port_string;
262 struct sockaddr_in sin;
271 /* Glibc 2.7 has a bug in strtok_r when compiling with optimization that
272 * can cause segfaults here:
273 * http://sources.redhat.com/bugzilla/show_bug.cgi?id=5614.
274 * Using "::" instead of the obvious ":" works around it. */
275 host_name = strtok_r(suffix, "::", &save_ptr);
276 port_string = strtok_r(NULL, "::", &save_ptr);
278 error(0, "%s: bad peer name format", name);
282 memset(&sin, 0, sizeof sin);
283 sin.sin_family = AF_INET;
284 if (lookup_ip(host_name, &sin.sin_addr)) {
287 sin.sin_port = htons(port_string && *port_string ? atoi(port_string)
291 fd = socket(AF_INET, SOCK_STREAM, 0);
293 VLOG_ERR("%s: socket: %s", name, strerror(errno));
296 retval = set_nonblocking(fd);
302 /* Connect socket. */
303 retval = connect(fd, (struct sockaddr *) &sin, sizeof sin);
305 if (errno == EINPROGRESS) {
306 return new_ssl_vconn(name, fd, CLIENT, STATE_TCP_CONNECTING,
310 VLOG_ERR("%s: connect: %s", name, strerror(error));
315 return new_ssl_vconn(name, fd, CLIENT, STATE_SSL_CONNECTING,
321 ssl_connect(struct vconn *vconn)
323 struct ssl_vconn *sslv = ssl_vconn_cast(vconn);
326 switch (sslv->state) {
327 case STATE_TCP_CONNECTING:
328 retval = check_connection_completion(sslv->fd);
332 sslv->state = STATE_SSL_CONNECTING;
335 case STATE_SSL_CONNECTING:
336 retval = (sslv->type == CLIENT
337 ? SSL_connect(sslv->ssl) : SSL_accept(sslv->ssl));
339 int error = SSL_get_error(sslv->ssl, retval);
340 if (retval < 0 && ssl_wants_io(error)) {
344 interpret_ssl_error((sslv->type == CLIENT ? "SSL_connect"
345 : "SSL_accept"), retval, error, &unused);
346 shutdown(sslv->fd, SHUT_RDWR);
358 ssl_close(struct vconn *vconn)
360 struct ssl_vconn *sslv = ssl_vconn_cast(vconn);
361 poll_cancel(sslv->tx_waiter);
368 interpret_ssl_error(const char *function, int ret, int error,
375 VLOG_ERR_RL(&rl, "%s: unexpected SSL_ERROR_NONE", function);
378 case SSL_ERROR_ZERO_RETURN:
379 VLOG_ERR_RL(&rl, "%s: unexpected SSL_ERROR_ZERO_RETURN", function);
382 case SSL_ERROR_WANT_READ:
386 case SSL_ERROR_WANT_WRITE:
390 case SSL_ERROR_WANT_CONNECT:
391 VLOG_ERR_RL(&rl, "%s: unexpected SSL_ERROR_WANT_CONNECT", function);
394 case SSL_ERROR_WANT_ACCEPT:
395 VLOG_ERR_RL(&rl, "%s: unexpected SSL_ERROR_WANT_ACCEPT", function);
398 case SSL_ERROR_WANT_X509_LOOKUP:
399 VLOG_ERR_RL(&rl, "%s: unexpected SSL_ERROR_WANT_X509_LOOKUP",
403 case SSL_ERROR_SYSCALL: {
404 int queued_error = ERR_get_error();
405 if (queued_error == 0) {
408 VLOG_WARN_RL(&rl, "%s: system error (%s)",
409 function, strerror(status));
412 VLOG_WARN_RL(&rl, "%s: unexpected SSL connection close",
417 VLOG_DBG_RL(&rl, "%s: %s",
418 function, ERR_error_string(queued_error, NULL));
423 case SSL_ERROR_SSL: {
424 int queued_error = ERR_get_error();
425 if (queued_error != 0) {
426 VLOG_DBG_RL(&rl, "%s: %s",
427 function, ERR_error_string(queued_error, NULL));
429 VLOG_ERR_RL(&rl, "%s: SSL_ERROR_SSL without queued error",
436 VLOG_ERR_RL(&rl, "%s: bad SSL error code %d", function, error);
443 ssl_recv(struct vconn *vconn, struct buffer **bufferp)
445 struct ssl_vconn *sslv = ssl_vconn_cast(vconn);
451 if (sslv->rxbuf == NULL) {
452 sslv->rxbuf = buffer_new(1564);
457 if (sizeof(struct ofp_header) > rx->size) {
458 want_bytes = sizeof(struct ofp_header) - rx->size;
460 struct ofp_header *oh = rx->data;
461 size_t length = ntohs(oh->length);
462 if (length < sizeof(struct ofp_header)) {
463 VLOG_ERR_RL(&rl, "received too-short ofp_header (%zu bytes)",
467 want_bytes = length - rx->size;
474 buffer_prealloc_tailroom(rx, want_bytes);
476 /* Behavior of zero-byte SSL_read is poorly defined. */
477 assert(want_bytes > 0);
479 old_state = SSL_get_state(sslv->ssl);
480 ret = SSL_read(sslv->ssl, buffer_tail(rx), want_bytes);
481 if (old_state != SSL_get_state(sslv->ssl)) {
482 sslv->tx_want = SSL_NOTHING;
483 if (sslv->tx_waiter) {
484 poll_cancel(sslv->tx_waiter);
485 ssl_tx_poll_callback(sslv->fd, POLLIN, vconn);
488 sslv->rx_want = SSL_NOTHING;
492 if (ret == want_bytes) {
493 if (rx->size > sizeof(struct ofp_header)) {
503 int error = SSL_get_error(sslv->ssl, ret);
504 if (error == SSL_ERROR_ZERO_RETURN) {
505 /* Connection closed (EOF). */
507 VLOG_WARN_RL(&rl, "SSL_read: unexpected connection close");
513 return interpret_ssl_error("SSL_read", ret, error, &sslv->rx_want);
519 ssl_clear_txbuf(struct ssl_vconn *sslv)
521 buffer_delete(sslv->txbuf);
523 sslv->tx_waiter = NULL;
527 ssl_register_tx_waiter(struct vconn *vconn)
529 struct ssl_vconn *sslv = ssl_vconn_cast(vconn);
530 sslv->tx_waiter = poll_fd_callback(sslv->fd,
531 want_to_poll_events(sslv->tx_want),
532 ssl_tx_poll_callback, vconn);
536 ssl_do_tx(struct vconn *vconn)
538 struct ssl_vconn *sslv = ssl_vconn_cast(vconn);
541 int old_state = SSL_get_state(sslv->ssl);
542 int ret = SSL_write(sslv->ssl, sslv->txbuf->data, sslv->txbuf->size);
543 if (old_state != SSL_get_state(sslv->ssl)) {
544 sslv->rx_want = SSL_NOTHING;
546 sslv->tx_want = SSL_NOTHING;
548 buffer_pull(sslv->txbuf, ret);
549 if (sslv->txbuf->size == 0) {
553 int ssl_error = SSL_get_error(sslv->ssl, ret);
554 if (ssl_error == SSL_ERROR_ZERO_RETURN) {
555 VLOG_WARN_RL(&rl, "SSL_write: connection closed");
558 return interpret_ssl_error("SSL_write", ret, ssl_error,
566 ssl_tx_poll_callback(int fd UNUSED, short int revents UNUSED, void *vconn_)
568 struct vconn *vconn = vconn_;
569 struct ssl_vconn *sslv = ssl_vconn_cast(vconn);
570 int error = ssl_do_tx(vconn);
571 if (error != EAGAIN) {
572 ssl_clear_txbuf(sslv);
574 ssl_register_tx_waiter(vconn);
579 ssl_send(struct vconn *vconn, struct buffer *buffer)
581 struct ssl_vconn *sslv = ssl_vconn_cast(vconn);
588 sslv->txbuf = buffer;
589 error = ssl_do_tx(vconn);
592 ssl_clear_txbuf(sslv);
595 ssl_register_tx_waiter(vconn);
605 ssl_wait(struct vconn *vconn, enum vconn_wait_type wait)
607 struct ssl_vconn *sslv = ssl_vconn_cast(vconn);
611 if (vconn_connect(vconn) != EAGAIN) {
612 poll_immediate_wake();
614 switch (sslv->state) {
615 case STATE_TCP_CONNECTING:
616 poll_fd_wait(sslv->fd, POLLOUT);
619 case STATE_SSL_CONNECTING:
620 /* ssl_connect() called SSL_accept() or SSL_connect(), which
621 * set up the status that we test here. */
622 poll_fd_wait(sslv->fd,
623 want_to_poll_events(SSL_want(sslv->ssl)));
633 if (sslv->rx_want != SSL_NOTHING) {
634 poll_fd_wait(sslv->fd, want_to_poll_events(sslv->rx_want));
636 poll_immediate_wake();
642 /* We have room in our tx queue. */
643 poll_immediate_wake();
645 /* The call to ssl_tx_poll_callback() will wake us up. */
654 struct vconn_class ssl_vconn_class = {
658 .connect = ssl_connect,
672 static struct pssl_vconn *
673 pssl_vconn_cast(struct vconn *vconn)
675 vconn_assert_class(vconn, &pssl_vconn_class);
676 return CONTAINER_OF(vconn, struct pssl_vconn, vconn);
680 pssl_open(const char *name, char *suffix, struct vconn **vconnp)
682 struct sockaddr_in sin;
683 struct pssl_vconn *pssl;
686 unsigned int yes = 1;
694 fd = socket(AF_INET, SOCK_STREAM, 0);
697 VLOG_ERR("%s: socket: %s", name, strerror(error));
701 if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof yes) < 0) {
703 VLOG_ERR("%s: setsockopt(SO_REUSEADDR): %s", name, strerror(errno));
707 memset(&sin, 0, sizeof sin);
708 sin.sin_family = AF_INET;
709 sin.sin_addr.s_addr = htonl(INADDR_ANY);
710 sin.sin_port = htons(atoi(suffix) ? atoi(suffix) : OFP_SSL_PORT);
711 retval = bind(fd, (struct sockaddr *) &sin, sizeof sin);
714 VLOG_ERR("%s: bind: %s", name, strerror(error));
719 retval = listen(fd, 10);
722 VLOG_ERR("%s: listen: %s", name, strerror(error));
727 retval = set_nonblocking(fd);
733 pssl = xmalloc(sizeof *pssl);
734 vconn_init(&pssl->vconn, &pssl_vconn_class, 0, 0, name);
736 *vconnp = &pssl->vconn;
741 pssl_close(struct vconn *vconn)
743 struct pssl_vconn *pssl = pssl_vconn_cast(vconn);
749 pssl_accept(struct vconn *vconn, struct vconn **new_vconnp)
751 struct pssl_vconn *pssl = pssl_vconn_cast(vconn);
752 struct sockaddr_in sin;
753 socklen_t sin_len = sizeof sin;
758 new_fd = accept(pssl->fd, &sin, &sin_len);
761 if (error != EAGAIN) {
762 VLOG_DBG_RL(&rl, "accept: %s", strerror(error));
767 error = set_nonblocking(new_fd);
773 sprintf(name, "ssl:"IP_FMT, IP_ARGS(&sin.sin_addr));
774 if (sin.sin_port != htons(OFP_SSL_PORT)) {
775 sprintf(strchr(name, '\0'), ":%"PRIu16, ntohs(sin.sin_port));
777 return new_ssl_vconn(name, new_fd, SERVER, STATE_SSL_CONNECTING, &sin,
782 pssl_wait(struct vconn *vconn, enum vconn_wait_type wait)
784 struct pssl_vconn *pssl = pssl_vconn_cast(vconn);
785 assert(wait == WAIT_ACCEPT);
786 poll_fd_wait(pssl->fd, POLLIN);
789 struct vconn_class pssl_vconn_class = {
793 .accept = pssl_accept,
798 * Returns true if OpenSSL error is WANT_READ or WANT_WRITE, indicating that
799 * OpenSSL is requesting that we call it back when the socket is ready for read
800 * or writing, respectively.
803 ssl_wants_io(int ssl_error)
805 return (ssl_error == SSL_ERROR_WANT_WRITE
806 || ssl_error == SSL_ERROR_WANT_READ);
812 static int init_status = -1;
813 if (init_status < 0) {
814 init_status = do_ssl_init();
815 assert(init_status >= 0);
826 SSL_load_error_strings();
828 method = TLSv1_method();
829 if (method == NULL) {
830 VLOG_ERR("TLSv1_method: %s", ERR_error_string(ERR_get_error(), NULL));
834 ctx = SSL_CTX_new(method);
836 VLOG_ERR("SSL_CTX_new: %s", ERR_error_string(ERR_get_error(), NULL));
839 SSL_CTX_set_options(ctx, SSL_OP_NO_SSLv2 | SSL_OP_NO_SSLv3);
840 SSL_CTX_set_tmp_dh_callback(ctx, tmp_dh_callback);
841 SSL_CTX_set_mode(ctx, SSL_MODE_ENABLE_PARTIAL_WRITE);
842 SSL_CTX_set_mode(ctx, SSL_MODE_ACCEPT_MOVING_WRITE_BUFFER);
843 SSL_CTX_set_verify(ctx, SSL_VERIFY_PEER | SSL_VERIFY_FAIL_IF_NO_PEER_CERT,
850 tmp_dh_callback(SSL *ssl, int is_export UNUSED, int keylength)
855 DH *(*constructor)(void);
858 static struct dh dh_table[] = {
859 {1024, NULL, get_dh1024},
860 {2048, NULL, get_dh2048},
861 {4096, NULL, get_dh4096},
866 for (dh = dh_table; dh < &dh_table[ARRAY_SIZE(dh_table)]; dh++) {
867 if (dh->keylength == keylength) {
869 dh->dh = dh->constructor();
871 fatal(ENOMEM, "out of memory constructing "
872 "Diffie-Hellman parameters");
878 VLOG_ERR_RL(&rl, "no Diffie-Hellman parameters for key length %d",
883 /* Returns true if SSL is at least partially configured. */
885 vconn_ssl_is_configured(void)
887 return has_private_key || has_certificate || has_ca_cert;
891 vconn_ssl_set_private_key_file(const char *file_name)
896 if (SSL_CTX_use_PrivateKey_file(ctx, file_name, SSL_FILETYPE_PEM) != 1) {
897 VLOG_ERR("SSL_use_PrivateKey_file: %s",
898 ERR_error_string(ERR_get_error(), NULL));
901 has_private_key = true;
905 vconn_ssl_set_certificate_file(const char *file_name)
910 if (SSL_CTX_use_certificate_chain_file(ctx, file_name) != 1) {
911 VLOG_ERR("SSL_use_certificate_file: %s",
912 ERR_error_string(ERR_get_error(), NULL));
915 has_certificate = true;
919 vconn_ssl_set_ca_cert_file(const char *file_name)
921 STACK_OF(X509_NAME) *ca_list;
927 /* Set up list of CAs that the server will accept from the client. */
928 ca_list = SSL_load_client_CA_file(file_name);
929 if (ca_list == NULL) {
930 VLOG_ERR("SSL_load_client_CA_file: %s",
931 ERR_error_string(ERR_get_error(), NULL));
934 SSL_CTX_set_client_CA_list(ctx, ca_list);
936 /* Set up CAs for OpenSSL to trust in verifying the peer's certificate. */
937 if (SSL_CTX_load_verify_locations(ctx, file_name, NULL) != 1) {
938 VLOG_ERR("SSL_CTX_load_verify_locations: %s",
939 ERR_error_string(ERR_get_error(), NULL));