qapi: Use returned bool to check for failure, manual part
[qemu/ar7.git] / block / ssh.c
blob13a29646218093ab8d220fcc1e9eb5f0bf95492d
1 /*
2 * Secure Shell (ssh) backend for QEMU.
4 * Copyright (C) 2013 Red Hat Inc., Richard W.M. Jones <rjones@redhat.com>
6 * Permission is hereby granted, free of charge, to any person obtaining a copy
7 * of this software and associated documentation files (the "Software"), to deal
8 * in the Software without restriction, including without limitation the rights
9 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
10 * copies of the Software, and to permit persons to whom the Software is
11 * furnished to do so, subject to the following conditions:
13 * The above copyright notice and this permission notice shall be included in
14 * all copies or substantial portions of the Software.
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
19 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
21 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
22 * THE SOFTWARE.
25 #include "qemu/osdep.h"
27 #include <libssh/libssh.h>
28 #include <libssh/sftp.h>
30 #include "block/block_int.h"
31 #include "block/qdict.h"
32 #include "qapi/error.h"
33 #include "qemu/error-report.h"
34 #include "qemu/module.h"
35 #include "qemu/option.h"
36 #include "qemu/ctype.h"
37 #include "qemu/cutils.h"
38 #include "qemu/sockets.h"
39 #include "qemu/uri.h"
40 #include "qapi/qapi-visit-sockets.h"
41 #include "qapi/qapi-visit-block-core.h"
42 #include "qapi/qmp/qdict.h"
43 #include "qapi/qmp/qstring.h"
44 #include "qapi/qobject-input-visitor.h"
45 #include "qapi/qobject-output-visitor.h"
46 #include "trace.h"
49 * TRACE_LIBSSH=<level> enables tracing in libssh itself.
50 * The meaning of <level> is described here:
51 * http://api.libssh.org/master/group__libssh__log.html
53 #define TRACE_LIBSSH 0 /* see: SSH_LOG_* */
55 typedef struct BDRVSSHState {
56 /* Coroutine. */
57 CoMutex lock;
59 /* SSH connection. */
60 int sock; /* socket */
61 ssh_session session; /* ssh session */
62 sftp_session sftp; /* sftp session */
63 sftp_file sftp_handle; /* sftp remote file handle */
66 * File attributes at open. We try to keep the .size field
67 * updated if it changes (eg by writing at the end of the file).
69 sftp_attributes attrs;
71 InetSocketAddress *inet;
73 /* Used to warn if 'flush' is not supported. */
74 bool unsafe_flush_warning;
77 * Store the user name for ssh_refresh_filename() because the
78 * default depends on the system you are on -- therefore, when we
79 * generate a filename, it should always contain the user name we
80 * are actually using.
82 char *user;
83 } BDRVSSHState;
85 static void ssh_state_init(BDRVSSHState *s)
87 memset(s, 0, sizeof *s);
88 s->sock = -1;
89 qemu_co_mutex_init(&s->lock);
92 static void ssh_state_free(BDRVSSHState *s)
94 g_free(s->user);
96 if (s->attrs) {
97 sftp_attributes_free(s->attrs);
99 if (s->sftp_handle) {
100 sftp_close(s->sftp_handle);
102 if (s->sftp) {
103 sftp_free(s->sftp);
105 if (s->session) {
106 ssh_disconnect(s->session);
107 ssh_free(s->session); /* This frees s->sock */
111 static void GCC_FMT_ATTR(3, 4)
112 session_error_setg(Error **errp, BDRVSSHState *s, const char *fs, ...)
114 va_list args;
115 char *msg;
117 va_start(args, fs);
118 msg = g_strdup_vprintf(fs, args);
119 va_end(args);
121 if (s->session) {
122 const char *ssh_err;
123 int ssh_err_code;
125 /* This is not an errno. See <libssh/libssh.h>. */
126 ssh_err = ssh_get_error(s->session);
127 ssh_err_code = ssh_get_error_code(s->session);
128 error_setg(errp, "%s: %s (libssh error code: %d)",
129 msg, ssh_err, ssh_err_code);
130 } else {
131 error_setg(errp, "%s", msg);
133 g_free(msg);
136 static void GCC_FMT_ATTR(3, 4)
137 sftp_error_setg(Error **errp, BDRVSSHState *s, const char *fs, ...)
139 va_list args;
140 char *msg;
142 va_start(args, fs);
143 msg = g_strdup_vprintf(fs, args);
144 va_end(args);
146 if (s->sftp) {
147 const char *ssh_err;
148 int ssh_err_code;
149 int sftp_err_code;
151 /* This is not an errno. See <libssh/libssh.h>. */
152 ssh_err = ssh_get_error(s->session);
153 ssh_err_code = ssh_get_error_code(s->session);
154 /* See <libssh/sftp.h>. */
155 sftp_err_code = sftp_get_error(s->sftp);
157 error_setg(errp,
158 "%s: %s (libssh error code: %d, sftp error code: %d)",
159 msg, ssh_err, ssh_err_code, sftp_err_code);
160 } else {
161 error_setg(errp, "%s", msg);
163 g_free(msg);
166 static void sftp_error_trace(BDRVSSHState *s, const char *op)
168 const char *ssh_err;
169 int ssh_err_code;
170 int sftp_err_code;
172 /* This is not an errno. See <libssh/libssh.h>. */
173 ssh_err = ssh_get_error(s->session);
174 ssh_err_code = ssh_get_error_code(s->session);
175 /* See <libssh/sftp.h>. */
176 sftp_err_code = sftp_get_error(s->sftp);
178 trace_sftp_error(op, ssh_err, ssh_err_code, sftp_err_code);
181 static int parse_uri(const char *filename, QDict *options, Error **errp)
183 URI *uri = NULL;
184 QueryParams *qp;
185 char *port_str;
186 int i;
188 uri = uri_parse(filename);
189 if (!uri) {
190 return -EINVAL;
193 if (g_strcmp0(uri->scheme, "ssh") != 0) {
194 error_setg(errp, "URI scheme must be 'ssh'");
195 goto err;
198 if (!uri->server || strcmp(uri->server, "") == 0) {
199 error_setg(errp, "missing hostname in URI");
200 goto err;
203 if (!uri->path || strcmp(uri->path, "") == 0) {
204 error_setg(errp, "missing remote path in URI");
205 goto err;
208 qp = query_params_parse(uri->query);
209 if (!qp) {
210 error_setg(errp, "could not parse query parameters");
211 goto err;
214 if(uri->user && strcmp(uri->user, "") != 0) {
215 qdict_put_str(options, "user", uri->user);
218 qdict_put_str(options, "server.host", uri->server);
220 port_str = g_strdup_printf("%d", uri->port ?: 22);
221 qdict_put_str(options, "server.port", port_str);
222 g_free(port_str);
224 qdict_put_str(options, "path", uri->path);
226 /* Pick out any query parameters that we understand, and ignore
227 * the rest.
229 for (i = 0; i < qp->n; ++i) {
230 if (strcmp(qp->p[i].name, "host_key_check") == 0) {
231 qdict_put_str(options, "host_key_check", qp->p[i].value);
235 query_params_free(qp);
236 uri_free(uri);
237 return 0;
239 err:
240 if (uri) {
241 uri_free(uri);
243 return -EINVAL;
246 static bool ssh_has_filename_options_conflict(QDict *options, Error **errp)
248 const QDictEntry *qe;
250 for (qe = qdict_first(options); qe; qe = qdict_next(options, qe)) {
251 if (!strcmp(qe->key, "host") ||
252 !strcmp(qe->key, "port") ||
253 !strcmp(qe->key, "path") ||
254 !strcmp(qe->key, "user") ||
255 !strcmp(qe->key, "host_key_check") ||
256 strstart(qe->key, "server.", NULL))
258 error_setg(errp, "Option '%s' cannot be used with a file name",
259 qe->key);
260 return true;
264 return false;
267 static void ssh_parse_filename(const char *filename, QDict *options,
268 Error **errp)
270 if (ssh_has_filename_options_conflict(options, errp)) {
271 return;
274 parse_uri(filename, options, errp);
277 static int check_host_key_knownhosts(BDRVSSHState *s, Error **errp)
279 int ret;
280 #ifdef HAVE_LIBSSH_0_8
281 enum ssh_known_hosts_e state;
282 int r;
283 ssh_key pubkey;
284 enum ssh_keytypes_e pubkey_type;
285 unsigned char *server_hash = NULL;
286 size_t server_hash_len;
287 char *fingerprint = NULL;
289 state = ssh_session_is_known_server(s->session);
290 trace_ssh_server_status(state);
292 switch (state) {
293 case SSH_KNOWN_HOSTS_OK:
294 /* OK */
295 trace_ssh_check_host_key_knownhosts();
296 break;
297 case SSH_KNOWN_HOSTS_CHANGED:
298 ret = -EINVAL;
299 r = ssh_get_server_publickey(s->session, &pubkey);
300 if (r == 0) {
301 r = ssh_get_publickey_hash(pubkey, SSH_PUBLICKEY_HASH_SHA256,
302 &server_hash, &server_hash_len);
303 pubkey_type = ssh_key_type(pubkey);
304 ssh_key_free(pubkey);
306 if (r == 0) {
307 fingerprint = ssh_get_fingerprint_hash(SSH_PUBLICKEY_HASH_SHA256,
308 server_hash,
309 server_hash_len);
310 ssh_clean_pubkey_hash(&server_hash);
312 if (fingerprint) {
313 error_setg(errp,
314 "host key (%s key with fingerprint %s) does not match "
315 "the one in known_hosts; this may be a possible attack",
316 ssh_key_type_to_char(pubkey_type), fingerprint);
317 ssh_string_free_char(fingerprint);
318 } else {
319 error_setg(errp,
320 "host key does not match the one in known_hosts; this "
321 "may be a possible attack");
323 goto out;
324 case SSH_KNOWN_HOSTS_OTHER:
325 ret = -EINVAL;
326 error_setg(errp,
327 "host key for this server not found, another type exists");
328 goto out;
329 case SSH_KNOWN_HOSTS_UNKNOWN:
330 ret = -EINVAL;
331 error_setg(errp, "no host key was found in known_hosts");
332 goto out;
333 case SSH_KNOWN_HOSTS_NOT_FOUND:
334 ret = -ENOENT;
335 error_setg(errp, "known_hosts file not found");
336 goto out;
337 case SSH_KNOWN_HOSTS_ERROR:
338 ret = -EINVAL;
339 error_setg(errp, "error while checking the host");
340 goto out;
341 default:
342 ret = -EINVAL;
343 error_setg(errp, "error while checking for known server (%d)", state);
344 goto out;
346 #else /* !HAVE_LIBSSH_0_8 */
347 int state;
349 state = ssh_is_server_known(s->session);
350 trace_ssh_server_status(state);
352 switch (state) {
353 case SSH_SERVER_KNOWN_OK:
354 /* OK */
355 trace_ssh_check_host_key_knownhosts();
356 break;
357 case SSH_SERVER_KNOWN_CHANGED:
358 ret = -EINVAL;
359 error_setg(errp,
360 "host key does not match the one in known_hosts; this "
361 "may be a possible attack");
362 goto out;
363 case SSH_SERVER_FOUND_OTHER:
364 ret = -EINVAL;
365 error_setg(errp,
366 "host key for this server not found, another type exists");
367 goto out;
368 case SSH_SERVER_FILE_NOT_FOUND:
369 ret = -ENOENT;
370 error_setg(errp, "known_hosts file not found");
371 goto out;
372 case SSH_SERVER_NOT_KNOWN:
373 ret = -EINVAL;
374 error_setg(errp, "no host key was found in known_hosts");
375 goto out;
376 case SSH_SERVER_ERROR:
377 ret = -EINVAL;
378 error_setg(errp, "server error");
379 goto out;
380 default:
381 ret = -EINVAL;
382 error_setg(errp, "error while checking for known server (%d)", state);
383 goto out;
385 #endif /* !HAVE_LIBSSH_0_8 */
387 /* known_hosts checking successful. */
388 ret = 0;
390 out:
391 return ret;
394 static unsigned hex2decimal(char ch)
396 if (ch >= '0' && ch <= '9') {
397 return (ch - '0');
398 } else if (ch >= 'a' && ch <= 'f') {
399 return 10 + (ch - 'a');
400 } else if (ch >= 'A' && ch <= 'F') {
401 return 10 + (ch - 'A');
404 return -1;
407 /* Compare the binary fingerprint (hash of host key) with the
408 * host_key_check parameter.
410 static int compare_fingerprint(const unsigned char *fingerprint, size_t len,
411 const char *host_key_check)
413 unsigned c;
415 while (len > 0) {
416 while (*host_key_check == ':')
417 host_key_check++;
418 if (!qemu_isxdigit(host_key_check[0]) ||
419 !qemu_isxdigit(host_key_check[1]))
420 return 1;
421 c = hex2decimal(host_key_check[0]) * 16 +
422 hex2decimal(host_key_check[1]);
423 if (c - *fingerprint != 0)
424 return c - *fingerprint;
425 fingerprint++;
426 len--;
427 host_key_check += 2;
429 return *host_key_check - '\0';
432 static int
433 check_host_key_hash(BDRVSSHState *s, const char *hash,
434 enum ssh_publickey_hash_type type, Error **errp)
436 int r;
437 ssh_key pubkey;
438 unsigned char *server_hash;
439 size_t server_hash_len;
441 #ifdef HAVE_LIBSSH_0_8
442 r = ssh_get_server_publickey(s->session, &pubkey);
443 #else
444 r = ssh_get_publickey(s->session, &pubkey);
445 #endif
446 if (r != SSH_OK) {
447 session_error_setg(errp, s, "failed to read remote host key");
448 return -EINVAL;
451 r = ssh_get_publickey_hash(pubkey, type, &server_hash, &server_hash_len);
452 ssh_key_free(pubkey);
453 if (r != 0) {
454 session_error_setg(errp, s,
455 "failed reading the hash of the server SSH key");
456 return -EINVAL;
459 r = compare_fingerprint(server_hash, server_hash_len, hash);
460 ssh_clean_pubkey_hash(&server_hash);
461 if (r != 0) {
462 error_setg(errp, "remote host key does not match host_key_check '%s'",
463 hash);
464 return -EPERM;
467 return 0;
470 static int check_host_key(BDRVSSHState *s, SshHostKeyCheck *hkc, Error **errp)
472 SshHostKeyCheckMode mode;
474 if (hkc) {
475 mode = hkc->mode;
476 } else {
477 mode = SSH_HOST_KEY_CHECK_MODE_KNOWN_HOSTS;
480 switch (mode) {
481 case SSH_HOST_KEY_CHECK_MODE_NONE:
482 return 0;
483 case SSH_HOST_KEY_CHECK_MODE_HASH:
484 if (hkc->u.hash.type == SSH_HOST_KEY_CHECK_HASH_TYPE_MD5) {
485 return check_host_key_hash(s, hkc->u.hash.hash,
486 SSH_PUBLICKEY_HASH_MD5, errp);
487 } else if (hkc->u.hash.type == SSH_HOST_KEY_CHECK_HASH_TYPE_SHA1) {
488 return check_host_key_hash(s, hkc->u.hash.hash,
489 SSH_PUBLICKEY_HASH_SHA1, errp);
491 g_assert_not_reached();
492 break;
493 case SSH_HOST_KEY_CHECK_MODE_KNOWN_HOSTS:
494 return check_host_key_knownhosts(s, errp);
495 default:
496 g_assert_not_reached();
499 return -EINVAL;
502 static int authenticate(BDRVSSHState *s, Error **errp)
504 int r, ret;
505 int method;
507 /* Try to authenticate with the "none" method. */
508 r = ssh_userauth_none(s->session, NULL);
509 if (r == SSH_AUTH_ERROR) {
510 ret = -EPERM;
511 session_error_setg(errp, s, "failed to authenticate using none "
512 "authentication");
513 goto out;
514 } else if (r == SSH_AUTH_SUCCESS) {
515 /* Authenticated! */
516 ret = 0;
517 goto out;
520 method = ssh_userauth_list(s->session, NULL);
521 trace_ssh_auth_methods(method);
524 * Try to authenticate with publickey, using the ssh-agent
525 * if available.
527 if (method & SSH_AUTH_METHOD_PUBLICKEY) {
528 r = ssh_userauth_publickey_auto(s->session, NULL, NULL);
529 if (r == SSH_AUTH_ERROR) {
530 ret = -EINVAL;
531 session_error_setg(errp, s, "failed to authenticate using "
532 "publickey authentication");
533 goto out;
534 } else if (r == SSH_AUTH_SUCCESS) {
535 /* Authenticated! */
536 ret = 0;
537 goto out;
541 ret = -EPERM;
542 error_setg(errp, "failed to authenticate using publickey authentication "
543 "and the identities held by your ssh-agent");
545 out:
546 return ret;
549 static QemuOptsList ssh_runtime_opts = {
550 .name = "ssh",
551 .head = QTAILQ_HEAD_INITIALIZER(ssh_runtime_opts.head),
552 .desc = {
554 .name = "host",
555 .type = QEMU_OPT_STRING,
556 .help = "Host to connect to",
559 .name = "port",
560 .type = QEMU_OPT_NUMBER,
561 .help = "Port to connect to",
564 .name = "host_key_check",
565 .type = QEMU_OPT_STRING,
566 .help = "Defines how and what to check the host key against",
568 { /* end of list */ }
572 static bool ssh_process_legacy_options(QDict *output_opts,
573 QemuOpts *legacy_opts,
574 Error **errp)
576 const char *host = qemu_opt_get(legacy_opts, "host");
577 const char *port = qemu_opt_get(legacy_opts, "port");
578 const char *host_key_check = qemu_opt_get(legacy_opts, "host_key_check");
580 if (!host && port) {
581 error_setg(errp, "port may not be used without host");
582 return false;
585 if (host) {
586 qdict_put_str(output_opts, "server.host", host);
587 qdict_put_str(output_opts, "server.port", port ?: stringify(22));
590 if (host_key_check) {
591 if (strcmp(host_key_check, "no") == 0) {
592 qdict_put_str(output_opts, "host-key-check.mode", "none");
593 } else if (strncmp(host_key_check, "md5:", 4) == 0) {
594 qdict_put_str(output_opts, "host-key-check.mode", "hash");
595 qdict_put_str(output_opts, "host-key-check.type", "md5");
596 qdict_put_str(output_opts, "host-key-check.hash",
597 &host_key_check[4]);
598 } else if (strncmp(host_key_check, "sha1:", 5) == 0) {
599 qdict_put_str(output_opts, "host-key-check.mode", "hash");
600 qdict_put_str(output_opts, "host-key-check.type", "sha1");
601 qdict_put_str(output_opts, "host-key-check.hash",
602 &host_key_check[5]);
603 } else if (strcmp(host_key_check, "yes") == 0) {
604 qdict_put_str(output_opts, "host-key-check.mode", "known_hosts");
605 } else {
606 error_setg(errp, "unknown host_key_check setting (%s)",
607 host_key_check);
608 return false;
612 return true;
615 static BlockdevOptionsSsh *ssh_parse_options(QDict *options, Error **errp)
617 BlockdevOptionsSsh *result = NULL;
618 QemuOpts *opts = NULL;
619 Error *local_err = NULL;
620 const QDictEntry *e;
621 Visitor *v;
623 /* Translate legacy options */
624 opts = qemu_opts_create(&ssh_runtime_opts, NULL, 0, &error_abort);
625 if (!qemu_opts_absorb_qdict(opts, options, &local_err)) {
626 error_propagate(errp, local_err);
627 goto fail;
630 if (!ssh_process_legacy_options(options, opts, errp)) {
631 goto fail;
634 /* Create the QAPI object */
635 v = qobject_input_visitor_new_flat_confused(options, errp);
636 if (!v) {
637 goto fail;
640 visit_type_BlockdevOptionsSsh(v, NULL, &result, &local_err);
641 visit_free(v);
643 if (local_err) {
644 error_propagate(errp, local_err);
645 goto fail;
648 /* Remove the processed options from the QDict (the visitor processes
649 * _all_ options in the QDict) */
650 while ((e = qdict_first(options))) {
651 qdict_del(options, e->key);
654 fail:
655 qemu_opts_del(opts);
656 return result;
659 static int connect_to_ssh(BDRVSSHState *s, BlockdevOptionsSsh *opts,
660 int ssh_flags, int creat_mode, Error **errp)
662 int r, ret;
663 unsigned int port = 0;
664 int new_sock = -1;
666 if (opts->has_user) {
667 s->user = g_strdup(opts->user);
668 } else {
669 s->user = g_strdup(g_get_user_name());
670 if (!s->user) {
671 error_setg_errno(errp, errno, "Can't get user name");
672 ret = -errno;
673 goto err;
677 /* Pop the config into our state object, Exit if invalid */
678 s->inet = opts->server;
679 opts->server = NULL;
681 if (qemu_strtoui(s->inet->port, NULL, 10, &port) < 0) {
682 error_setg(errp, "Use only numeric port value");
683 ret = -EINVAL;
684 goto err;
687 /* Open the socket and connect. */
688 new_sock = inet_connect_saddr(s->inet, errp);
689 if (new_sock < 0) {
690 ret = -EIO;
691 goto err;
695 * Try to disable the Nagle algorithm on TCP sockets to reduce latency,
696 * but do not fail if it cannot be disabled.
698 r = socket_set_nodelay(new_sock);
699 if (r < 0) {
700 warn_report("can't set TCP_NODELAY for the ssh server %s: %s",
701 s->inet->host, strerror(errno));
704 /* Create SSH session. */
705 s->session = ssh_new();
706 if (!s->session) {
707 ret = -EINVAL;
708 session_error_setg(errp, s, "failed to initialize libssh session");
709 goto err;
713 * Make sure we are in blocking mode during the connection and
714 * authentication phases.
716 ssh_set_blocking(s->session, 1);
718 r = ssh_options_set(s->session, SSH_OPTIONS_USER, s->user);
719 if (r < 0) {
720 ret = -EINVAL;
721 session_error_setg(errp, s,
722 "failed to set the user in the libssh session");
723 goto err;
726 r = ssh_options_set(s->session, SSH_OPTIONS_HOST, s->inet->host);
727 if (r < 0) {
728 ret = -EINVAL;
729 session_error_setg(errp, s,
730 "failed to set the host in the libssh session");
731 goto err;
734 if (port > 0) {
735 r = ssh_options_set(s->session, SSH_OPTIONS_PORT, &port);
736 if (r < 0) {
737 ret = -EINVAL;
738 session_error_setg(errp, s,
739 "failed to set the port in the libssh session");
740 goto err;
744 r = ssh_options_set(s->session, SSH_OPTIONS_COMPRESSION, "none");
745 if (r < 0) {
746 ret = -EINVAL;
747 session_error_setg(errp, s,
748 "failed to disable the compression in the libssh "
749 "session");
750 goto err;
753 /* Read ~/.ssh/config. */
754 r = ssh_options_parse_config(s->session, NULL);
755 if (r < 0) {
756 ret = -EINVAL;
757 session_error_setg(errp, s, "failed to parse ~/.ssh/config");
758 goto err;
761 r = ssh_options_set(s->session, SSH_OPTIONS_FD, &new_sock);
762 if (r < 0) {
763 ret = -EINVAL;
764 session_error_setg(errp, s,
765 "failed to set the socket in the libssh session");
766 goto err;
768 /* libssh took ownership of the socket. */
769 s->sock = new_sock;
770 new_sock = -1;
772 /* Connect. */
773 r = ssh_connect(s->session);
774 if (r != SSH_OK) {
775 ret = -EINVAL;
776 session_error_setg(errp, s, "failed to establish SSH session");
777 goto err;
780 /* Check the remote host's key against known_hosts. */
781 ret = check_host_key(s, opts->host_key_check, errp);
782 if (ret < 0) {
783 goto err;
786 /* Authenticate. */
787 ret = authenticate(s, errp);
788 if (ret < 0) {
789 goto err;
792 /* Start SFTP. */
793 s->sftp = sftp_new(s->session);
794 if (!s->sftp) {
795 session_error_setg(errp, s, "failed to create sftp handle");
796 ret = -EINVAL;
797 goto err;
800 r = sftp_init(s->sftp);
801 if (r < 0) {
802 sftp_error_setg(errp, s, "failed to initialize sftp handle");
803 ret = -EINVAL;
804 goto err;
807 /* Open the remote file. */
808 trace_ssh_connect_to_ssh(opts->path, ssh_flags, creat_mode);
809 s->sftp_handle = sftp_open(s->sftp, opts->path, ssh_flags, creat_mode);
810 if (!s->sftp_handle) {
811 sftp_error_setg(errp, s, "failed to open remote file '%s'",
812 opts->path);
813 ret = -EINVAL;
814 goto err;
817 /* Make sure the SFTP file is handled in blocking mode. */
818 sftp_file_set_blocking(s->sftp_handle);
820 s->attrs = sftp_fstat(s->sftp_handle);
821 if (!s->attrs) {
822 sftp_error_setg(errp, s, "failed to read file attributes");
823 return -EINVAL;
826 return 0;
828 err:
829 if (s->attrs) {
830 sftp_attributes_free(s->attrs);
832 s->attrs = NULL;
833 if (s->sftp_handle) {
834 sftp_close(s->sftp_handle);
836 s->sftp_handle = NULL;
837 if (s->sftp) {
838 sftp_free(s->sftp);
840 s->sftp = NULL;
841 if (s->session) {
842 ssh_disconnect(s->session);
843 ssh_free(s->session);
845 s->session = NULL;
846 s->sock = -1;
847 if (new_sock >= 0) {
848 close(new_sock);
851 return ret;
854 static int ssh_file_open(BlockDriverState *bs, QDict *options, int bdrv_flags,
855 Error **errp)
857 BDRVSSHState *s = bs->opaque;
858 BlockdevOptionsSsh *opts;
859 int ret;
860 int ssh_flags;
862 ssh_state_init(s);
864 ssh_flags = 0;
865 if (bdrv_flags & BDRV_O_RDWR) {
866 ssh_flags |= O_RDWR;
867 } else {
868 ssh_flags |= O_RDONLY;
871 opts = ssh_parse_options(options, errp);
872 if (opts == NULL) {
873 return -EINVAL;
876 /* Start up SSH. */
877 ret = connect_to_ssh(s, opts, ssh_flags, 0, errp);
878 if (ret < 0) {
879 goto err;
882 /* Go non-blocking. */
883 ssh_set_blocking(s->session, 0);
885 if (s->attrs->type == SSH_FILEXFER_TYPE_REGULAR) {
886 bs->supported_truncate_flags = BDRV_REQ_ZERO_WRITE;
889 qapi_free_BlockdevOptionsSsh(opts);
891 return 0;
893 err:
894 qapi_free_BlockdevOptionsSsh(opts);
896 return ret;
899 /* Note: This is a blocking operation */
900 static int ssh_grow_file(BDRVSSHState *s, int64_t offset, Error **errp)
902 ssize_t ret;
903 char c[1] = { '\0' };
904 int was_blocking = ssh_is_blocking(s->session);
906 /* offset must be strictly greater than the current size so we do
907 * not overwrite anything */
908 assert(offset > 0 && offset > s->attrs->size);
910 ssh_set_blocking(s->session, 1);
912 sftp_seek64(s->sftp_handle, offset - 1);
913 ret = sftp_write(s->sftp_handle, c, 1);
915 ssh_set_blocking(s->session, was_blocking);
917 if (ret < 0) {
918 sftp_error_setg(errp, s, "Failed to grow file");
919 return -EIO;
922 s->attrs->size = offset;
923 return 0;
926 static QemuOptsList ssh_create_opts = {
927 .name = "ssh-create-opts",
928 .head = QTAILQ_HEAD_INITIALIZER(ssh_create_opts.head),
929 .desc = {
931 .name = BLOCK_OPT_SIZE,
932 .type = QEMU_OPT_SIZE,
933 .help = "Virtual disk size"
935 { /* end of list */ }
939 static int ssh_co_create(BlockdevCreateOptions *options, Error **errp)
941 BlockdevCreateOptionsSsh *opts = &options->u.ssh;
942 BDRVSSHState s;
943 int ret;
945 assert(options->driver == BLOCKDEV_DRIVER_SSH);
947 ssh_state_init(&s);
949 ret = connect_to_ssh(&s, opts->location,
950 O_RDWR | O_CREAT | O_TRUNC,
951 0644, errp);
952 if (ret < 0) {
953 goto fail;
956 if (opts->size > 0) {
957 ret = ssh_grow_file(&s, opts->size, errp);
958 if (ret < 0) {
959 goto fail;
963 ret = 0;
964 fail:
965 ssh_state_free(&s);
966 return ret;
969 static int coroutine_fn ssh_co_create_opts(BlockDriver *drv,
970 const char *filename,
971 QemuOpts *opts,
972 Error **errp)
974 BlockdevCreateOptions *create_options;
975 BlockdevCreateOptionsSsh *ssh_opts;
976 int ret;
977 QDict *uri_options = NULL;
979 create_options = g_new0(BlockdevCreateOptions, 1);
980 create_options->driver = BLOCKDEV_DRIVER_SSH;
981 ssh_opts = &create_options->u.ssh;
983 /* Get desired file size. */
984 ssh_opts->size = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0),
985 BDRV_SECTOR_SIZE);
986 trace_ssh_co_create_opts(ssh_opts->size);
988 uri_options = qdict_new();
989 ret = parse_uri(filename, uri_options, errp);
990 if (ret < 0) {
991 goto out;
994 ssh_opts->location = ssh_parse_options(uri_options, errp);
995 if (ssh_opts->location == NULL) {
996 ret = -EINVAL;
997 goto out;
1000 ret = ssh_co_create(create_options, errp);
1002 out:
1003 qobject_unref(uri_options);
1004 qapi_free_BlockdevCreateOptions(create_options);
1005 return ret;
1008 static void ssh_close(BlockDriverState *bs)
1010 BDRVSSHState *s = bs->opaque;
1012 ssh_state_free(s);
1015 static int ssh_has_zero_init(BlockDriverState *bs)
1017 BDRVSSHState *s = bs->opaque;
1018 /* Assume false, unless we can positively prove it's true. */
1019 int has_zero_init = 0;
1021 if (s->attrs->type == SSH_FILEXFER_TYPE_REGULAR) {
1022 has_zero_init = 1;
1025 return has_zero_init;
1028 typedef struct BDRVSSHRestart {
1029 BlockDriverState *bs;
1030 Coroutine *co;
1031 } BDRVSSHRestart;
1033 static void restart_coroutine(void *opaque)
1035 BDRVSSHRestart *restart = opaque;
1036 BlockDriverState *bs = restart->bs;
1037 BDRVSSHState *s = bs->opaque;
1038 AioContext *ctx = bdrv_get_aio_context(bs);
1040 trace_ssh_restart_coroutine(restart->co);
1041 aio_set_fd_handler(ctx, s->sock, false, NULL, NULL, NULL, NULL);
1043 aio_co_wake(restart->co);
1046 /* A non-blocking call returned EAGAIN, so yield, ensuring the
1047 * handlers are set up so that we'll be rescheduled when there is an
1048 * interesting event on the socket.
1050 static coroutine_fn void co_yield(BDRVSSHState *s, BlockDriverState *bs)
1052 int r;
1053 IOHandler *rd_handler = NULL, *wr_handler = NULL;
1054 BDRVSSHRestart restart = {
1055 .bs = bs,
1056 .co = qemu_coroutine_self()
1059 r = ssh_get_poll_flags(s->session);
1061 if (r & SSH_READ_PENDING) {
1062 rd_handler = restart_coroutine;
1064 if (r & SSH_WRITE_PENDING) {
1065 wr_handler = restart_coroutine;
1068 trace_ssh_co_yield(s->sock, rd_handler, wr_handler);
1070 aio_set_fd_handler(bdrv_get_aio_context(bs), s->sock,
1071 false, rd_handler, wr_handler, NULL, &restart);
1072 qemu_coroutine_yield();
1073 trace_ssh_co_yield_back(s->sock);
1076 static coroutine_fn int ssh_read(BDRVSSHState *s, BlockDriverState *bs,
1077 int64_t offset, size_t size,
1078 QEMUIOVector *qiov)
1080 ssize_t r;
1081 size_t got;
1082 char *buf, *end_of_vec;
1083 struct iovec *i;
1085 trace_ssh_read(offset, size);
1087 trace_ssh_seek(offset);
1088 sftp_seek64(s->sftp_handle, offset);
1090 /* This keeps track of the current iovec element ('i'), where we
1091 * will write to next ('buf'), and the end of the current iovec
1092 * ('end_of_vec').
1094 i = &qiov->iov[0];
1095 buf = i->iov_base;
1096 end_of_vec = i->iov_base + i->iov_len;
1098 for (got = 0; got < size; ) {
1099 size_t request_read_size;
1100 again:
1102 * The size of SFTP packets is limited to 32K bytes, so limit
1103 * the amount of data requested to 16K, as libssh currently
1104 * does not handle multiple requests on its own.
1106 request_read_size = MIN(end_of_vec - buf, 16384);
1107 trace_ssh_read_buf(buf, end_of_vec - buf, request_read_size);
1108 r = sftp_read(s->sftp_handle, buf, request_read_size);
1109 trace_ssh_read_return(r, sftp_get_error(s->sftp));
1111 if (r == SSH_AGAIN) {
1112 co_yield(s, bs);
1113 goto again;
1115 if (r == SSH_EOF || (r == 0 && sftp_get_error(s->sftp) == SSH_FX_EOF)) {
1116 /* EOF: Short read so pad the buffer with zeroes and return it. */
1117 qemu_iovec_memset(qiov, got, 0, size - got);
1118 return 0;
1120 if (r <= 0) {
1121 sftp_error_trace(s, "read");
1122 return -EIO;
1125 got += r;
1126 buf += r;
1127 if (buf >= end_of_vec && got < size) {
1128 i++;
1129 buf = i->iov_base;
1130 end_of_vec = i->iov_base + i->iov_len;
1134 return 0;
1137 static coroutine_fn int ssh_co_readv(BlockDriverState *bs,
1138 int64_t sector_num,
1139 int nb_sectors, QEMUIOVector *qiov)
1141 BDRVSSHState *s = bs->opaque;
1142 int ret;
1144 qemu_co_mutex_lock(&s->lock);
1145 ret = ssh_read(s, bs, sector_num * BDRV_SECTOR_SIZE,
1146 nb_sectors * BDRV_SECTOR_SIZE, qiov);
1147 qemu_co_mutex_unlock(&s->lock);
1149 return ret;
1152 static int ssh_write(BDRVSSHState *s, BlockDriverState *bs,
1153 int64_t offset, size_t size,
1154 QEMUIOVector *qiov)
1156 ssize_t r;
1157 size_t written;
1158 char *buf, *end_of_vec;
1159 struct iovec *i;
1161 trace_ssh_write(offset, size);
1163 trace_ssh_seek(offset);
1164 sftp_seek64(s->sftp_handle, offset);
1166 /* This keeps track of the current iovec element ('i'), where we
1167 * will read from next ('buf'), and the end of the current iovec
1168 * ('end_of_vec').
1170 i = &qiov->iov[0];
1171 buf = i->iov_base;
1172 end_of_vec = i->iov_base + i->iov_len;
1174 for (written = 0; written < size; ) {
1175 size_t request_write_size;
1176 again:
1178 * Avoid too large data packets, as libssh currently does not
1179 * handle multiple requests on its own.
1181 request_write_size = MIN(end_of_vec - buf, 131072);
1182 trace_ssh_write_buf(buf, end_of_vec - buf, request_write_size);
1183 r = sftp_write(s->sftp_handle, buf, request_write_size);
1184 trace_ssh_write_return(r, sftp_get_error(s->sftp));
1186 if (r == SSH_AGAIN) {
1187 co_yield(s, bs);
1188 goto again;
1190 if (r < 0) {
1191 sftp_error_trace(s, "write");
1192 return -EIO;
1195 written += r;
1196 buf += r;
1197 if (buf >= end_of_vec && written < size) {
1198 i++;
1199 buf = i->iov_base;
1200 end_of_vec = i->iov_base + i->iov_len;
1203 if (offset + written > s->attrs->size) {
1204 s->attrs->size = offset + written;
1208 return 0;
1211 static coroutine_fn int ssh_co_writev(BlockDriverState *bs,
1212 int64_t sector_num,
1213 int nb_sectors, QEMUIOVector *qiov,
1214 int flags)
1216 BDRVSSHState *s = bs->opaque;
1217 int ret;
1219 assert(!flags);
1220 qemu_co_mutex_lock(&s->lock);
1221 ret = ssh_write(s, bs, sector_num * BDRV_SECTOR_SIZE,
1222 nb_sectors * BDRV_SECTOR_SIZE, qiov);
1223 qemu_co_mutex_unlock(&s->lock);
1225 return ret;
1228 static void unsafe_flush_warning(BDRVSSHState *s, const char *what)
1230 if (!s->unsafe_flush_warning) {
1231 warn_report("ssh server %s does not support fsync",
1232 s->inet->host);
1233 if (what) {
1234 error_report("to support fsync, you need %s", what);
1236 s->unsafe_flush_warning = true;
1240 #ifdef HAVE_LIBSSH_0_8
1242 static coroutine_fn int ssh_flush(BDRVSSHState *s, BlockDriverState *bs)
1244 int r;
1246 trace_ssh_flush();
1248 if (!sftp_extension_supported(s->sftp, "fsync@openssh.com", "1")) {
1249 unsafe_flush_warning(s, "OpenSSH >= 6.3");
1250 return 0;
1252 again:
1253 r = sftp_fsync(s->sftp_handle);
1254 if (r == SSH_AGAIN) {
1255 co_yield(s, bs);
1256 goto again;
1258 if (r < 0) {
1259 sftp_error_trace(s, "fsync");
1260 return -EIO;
1263 return 0;
1266 static coroutine_fn int ssh_co_flush(BlockDriverState *bs)
1268 BDRVSSHState *s = bs->opaque;
1269 int ret;
1271 qemu_co_mutex_lock(&s->lock);
1272 ret = ssh_flush(s, bs);
1273 qemu_co_mutex_unlock(&s->lock);
1275 return ret;
1278 #else /* !HAVE_LIBSSH_0_8 */
1280 static coroutine_fn int ssh_co_flush(BlockDriverState *bs)
1282 BDRVSSHState *s = bs->opaque;
1284 unsafe_flush_warning(s, "libssh >= 0.8.0");
1285 return 0;
1288 #endif /* !HAVE_LIBSSH_0_8 */
1290 static int64_t ssh_getlength(BlockDriverState *bs)
1292 BDRVSSHState *s = bs->opaque;
1293 int64_t length;
1295 /* Note we cannot make a libssh call here. */
1296 length = (int64_t) s->attrs->size;
1297 trace_ssh_getlength(length);
1299 return length;
1302 static int coroutine_fn ssh_co_truncate(BlockDriverState *bs, int64_t offset,
1303 bool exact, PreallocMode prealloc,
1304 BdrvRequestFlags flags, Error **errp)
1306 BDRVSSHState *s = bs->opaque;
1308 if (prealloc != PREALLOC_MODE_OFF) {
1309 error_setg(errp, "Unsupported preallocation mode '%s'",
1310 PreallocMode_str(prealloc));
1311 return -ENOTSUP;
1314 if (offset < s->attrs->size) {
1315 error_setg(errp, "ssh driver does not support shrinking files");
1316 return -ENOTSUP;
1319 if (offset == s->attrs->size) {
1320 return 0;
1323 return ssh_grow_file(s, offset, errp);
1326 static void ssh_refresh_filename(BlockDriverState *bs)
1328 BDRVSSHState *s = bs->opaque;
1329 const char *path, *host_key_check;
1330 int ret;
1333 * None of these options can be represented in a plain "host:port"
1334 * format, so if any was given, we have to abort.
1336 if (s->inet->has_ipv4 || s->inet->has_ipv6 || s->inet->has_to ||
1337 s->inet->has_numeric)
1339 return;
1342 path = qdict_get_try_str(bs->full_open_options, "path");
1343 assert(path); /* mandatory option */
1345 host_key_check = qdict_get_try_str(bs->full_open_options, "host_key_check");
1347 ret = snprintf(bs->exact_filename, sizeof(bs->exact_filename),
1348 "ssh://%s@%s:%s%s%s%s",
1349 s->user, s->inet->host, s->inet->port, path,
1350 host_key_check ? "?host_key_check=" : "",
1351 host_key_check ?: "");
1352 if (ret >= sizeof(bs->exact_filename)) {
1353 /* An overflow makes the filename unusable, so do not report any */
1354 bs->exact_filename[0] = '\0';
1358 static char *ssh_bdrv_dirname(BlockDriverState *bs, Error **errp)
1360 if (qdict_haskey(bs->full_open_options, "host_key_check")) {
1362 * We cannot generate a simple prefix if we would have to
1363 * append a query string.
1365 error_setg(errp,
1366 "Cannot generate a base directory with host_key_check set");
1367 return NULL;
1370 if (bs->exact_filename[0] == '\0') {
1371 error_setg(errp, "Cannot generate a base directory for this ssh node");
1372 return NULL;
1375 return path_combine(bs->exact_filename, "");
1378 static const char *const ssh_strong_runtime_opts[] = {
1379 "host",
1380 "port",
1381 "path",
1382 "user",
1383 "host_key_check",
1384 "server.",
1386 NULL
1389 static BlockDriver bdrv_ssh = {
1390 .format_name = "ssh",
1391 .protocol_name = "ssh",
1392 .instance_size = sizeof(BDRVSSHState),
1393 .bdrv_parse_filename = ssh_parse_filename,
1394 .bdrv_file_open = ssh_file_open,
1395 .bdrv_co_create = ssh_co_create,
1396 .bdrv_co_create_opts = ssh_co_create_opts,
1397 .bdrv_close = ssh_close,
1398 .bdrv_has_zero_init = ssh_has_zero_init,
1399 .bdrv_co_readv = ssh_co_readv,
1400 .bdrv_co_writev = ssh_co_writev,
1401 .bdrv_getlength = ssh_getlength,
1402 .bdrv_co_truncate = ssh_co_truncate,
1403 .bdrv_co_flush_to_disk = ssh_co_flush,
1404 .bdrv_refresh_filename = ssh_refresh_filename,
1405 .bdrv_dirname = ssh_bdrv_dirname,
1406 .create_opts = &ssh_create_opts,
1407 .strong_runtime_opts = ssh_strong_runtime_opts,
1410 static void bdrv_ssh_init(void)
1412 int r;
1414 r = ssh_init();
1415 if (r != 0) {
1416 fprintf(stderr, "libssh initialization failed, %d\n", r);
1417 exit(EXIT_FAILURE);
1420 #if TRACE_LIBSSH != 0
1421 ssh_set_log_level(TRACE_LIBSSH);
1422 #endif
1424 bdrv_register(&bdrv_ssh);
1427 block_init(bdrv_ssh_init);