error: Eliminate error_propagate() with Coccinelle, part 2
[qemu.git] / block / ssh.c
1 /*
2 * Secure Shell (ssh) backend for QEMU.
3 *
4 * Copyright (C) 2013 Red Hat Inc., Richard W.M. Jones <rjones@redhat.com>
5 *
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:
12 *
13 * The above copyright notice and this permission notice shall be included in
14 * all copies or substantial portions of the Software.
15 *
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.
23 */
24
25 #include "qemu/osdep.h"
26
27 #include <libssh/libssh.h>
28 #include <libssh/sftp.h>
29
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"
47
48 /*
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
52 */
53 #define TRACE_LIBSSH 0 /* see: SSH_LOG_* */
54
55 typedef struct BDRVSSHState {
56 /* Coroutine. */
57 CoMutex lock;
58
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 */
64
65 /*
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).
68 */
69 sftp_attributes attrs;
70
71 InetSocketAddress *inet;
72
73 /* Used to warn if 'flush' is not supported. */
74 bool unsafe_flush_warning;
75
76 /*
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.
81 */
82 char *user;
83 } BDRVSSHState;
84
85 static void ssh_state_init(BDRVSSHState *s)
86 {
87 memset(s, 0, sizeof *s);
88 s->sock = -1;
89 qemu_co_mutex_init(&s->lock);
90 }
91
92 static void ssh_state_free(BDRVSSHState *s)
93 {
94 g_free(s->user);
95
96 if (s->attrs) {
97 sftp_attributes_free(s->attrs);
98 }
99 if (s->sftp_handle) {
100 sftp_close(s->sftp_handle);
101 }
102 if (s->sftp) {
103 sftp_free(s->sftp);
104 }
105 if (s->session) {
106 ssh_disconnect(s->session);
107 ssh_free(s->session); /* This frees s->sock */
108 }
109 }
110
111 static void GCC_FMT_ATTR(3, 4)
112 session_error_setg(Error **errp, BDRVSSHState *s, const char *fs, ...)
113 {
114 va_list args;
115 char *msg;
116
117 va_start(args, fs);
118 msg = g_strdup_vprintf(fs, args);
119 va_end(args);
120
121 if (s->session) {
122 const char *ssh_err;
123 int ssh_err_code;
124
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);
132 }
133 g_free(msg);
134 }
135
136 static void GCC_FMT_ATTR(3, 4)
137 sftp_error_setg(Error **errp, BDRVSSHState *s, const char *fs, ...)
138 {
139 va_list args;
140 char *msg;
141
142 va_start(args, fs);
143 msg = g_strdup_vprintf(fs, args);
144 va_end(args);
145
146 if (s->sftp) {
147 const char *ssh_err;
148 int ssh_err_code;
149 int sftp_err_code;
150
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);
156
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);
162 }
163 g_free(msg);
164 }
165
166 static void sftp_error_trace(BDRVSSHState *s, const char *op)
167 {
168 const char *ssh_err;
169 int ssh_err_code;
170 int sftp_err_code;
171
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);
177
178 trace_sftp_error(op, ssh_err, ssh_err_code, sftp_err_code);
179 }
180
181 static int parse_uri(const char *filename, QDict *options, Error **errp)
182 {
183 URI *uri = NULL;
184 QueryParams *qp;
185 char *port_str;
186 int i;
187
188 uri = uri_parse(filename);
189 if (!uri) {
190 return -EINVAL;
191 }
192
193 if (g_strcmp0(uri->scheme, "ssh") != 0) {
194 error_setg(errp, "URI scheme must be 'ssh'");
195 goto err;
196 }
197
198 if (!uri->server || strcmp(uri->server, "") == 0) {
199 error_setg(errp, "missing hostname in URI");
200 goto err;
201 }
202
203 if (!uri->path || strcmp(uri->path, "") == 0) {
204 error_setg(errp, "missing remote path in URI");
205 goto err;
206 }
207
208 qp = query_params_parse(uri->query);
209 if (!qp) {
210 error_setg(errp, "could not parse query parameters");
211 goto err;
212 }
213
214 if(uri->user && strcmp(uri->user, "") != 0) {
215 qdict_put_str(options, "user", uri->user);
216 }
217
218 qdict_put_str(options, "server.host", uri->server);
219
220 port_str = g_strdup_printf("%d", uri->port ?: 22);
221 qdict_put_str(options, "server.port", port_str);
222 g_free(port_str);
223
224 qdict_put_str(options, "path", uri->path);
225
226 /* Pick out any query parameters that we understand, and ignore
227 * the rest.
228 */
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);
232 }
233 }
234
235 query_params_free(qp);
236 uri_free(uri);
237 return 0;
238
239 err:
240 if (uri) {
241 uri_free(uri);
242 }
243 return -EINVAL;
244 }
245
246 static bool ssh_has_filename_options_conflict(QDict *options, Error **errp)
247 {
248 const QDictEntry *qe;
249
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))
257 {
258 error_setg(errp, "Option '%s' cannot be used with a file name",
259 qe->key);
260 return true;
261 }
262 }
263
264 return false;
265 }
266
267 static void ssh_parse_filename(const char *filename, QDict *options,
268 Error **errp)
269 {
270 if (ssh_has_filename_options_conflict(options, errp)) {
271 return;
272 }
273
274 parse_uri(filename, options, errp);
275 }
276
277 static int check_host_key_knownhosts(BDRVSSHState *s, Error **errp)
278 {
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;
288
289 state = ssh_session_is_known_server(s->session);
290 trace_ssh_server_status(state);
291
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);
305 }
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);
311 }
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");
322 }
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;
345 }
346 #else /* !HAVE_LIBSSH_0_8 */
347 int state;
348
349 state = ssh_is_server_known(s->session);
350 trace_ssh_server_status(state);
351
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;
384 }
385 #endif /* !HAVE_LIBSSH_0_8 */
386
387 /* known_hosts checking successful. */
388 ret = 0;
389
390 out:
391 return ret;
392 }
393
394 static unsigned hex2decimal(char ch)
395 {
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');
402 }
403
404 return -1;
405 }
406
407 /* Compare the binary fingerprint (hash of host key) with the
408 * host_key_check parameter.
409 */
410 static int compare_fingerprint(const unsigned char *fingerprint, size_t len,
411 const char *host_key_check)
412 {
413 unsigned c;
414
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;
428 }
429 return *host_key_check - '\0';
430 }
431
432 static int
433 check_host_key_hash(BDRVSSHState *s, const char *hash,
434 enum ssh_publickey_hash_type type, Error **errp)
435 {
436 int r;
437 ssh_key pubkey;
438 unsigned char *server_hash;
439 size_t server_hash_len;
440
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;
449 }
450
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;
457 }
458
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;
465 }
466
467 return 0;
468 }
469
470 static int check_host_key(BDRVSSHState *s, SshHostKeyCheck *hkc, Error **errp)
471 {
472 SshHostKeyCheckMode mode;
473
474 if (hkc) {
475 mode = hkc->mode;
476 } else {
477 mode = SSH_HOST_KEY_CHECK_MODE_KNOWN_HOSTS;
478 }
479
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);
490 }
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();
497 }
498
499 return -EINVAL;
500 }
501
502 static int authenticate(BDRVSSHState *s, Error **errp)
503 {
504 int r, ret;
505 int method;
506
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;
518 }
519
520 method = ssh_userauth_list(s->session, NULL);
521 trace_ssh_auth_methods(method);
522
523 /*
524 * Try to authenticate with publickey, using the ssh-agent
525 * if available.
526 */
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;
538 }
539 }
540
541 ret = -EPERM;
542 error_setg(errp, "failed to authenticate using publickey authentication "
543 "and the identities held by your ssh-agent");
544
545 out:
546 return ret;
547 }
548
549 static QemuOptsList ssh_runtime_opts = {
550 .name = "ssh",
551 .head = QTAILQ_HEAD_INITIALIZER(ssh_runtime_opts.head),
552 .desc = {
553 {
554 .name = "host",
555 .type = QEMU_OPT_STRING,
556 .help = "Host to connect to",
557 },
558 {
559 .name = "port",
560 .type = QEMU_OPT_NUMBER,
561 .help = "Port to connect to",
562 },
563 {
564 .name = "host_key_check",
565 .type = QEMU_OPT_STRING,
566 .help = "Defines how and what to check the host key against",
567 },
568 { /* end of list */ }
569 },
570 };
571
572 static bool ssh_process_legacy_options(QDict *output_opts,
573 QemuOpts *legacy_opts,
574 Error **errp)
575 {
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");
579
580 if (!host && port) {
581 error_setg(errp, "port may not be used without host");
582 return false;
583 }
584
585 if (host) {
586 qdict_put_str(output_opts, "server.host", host);
587 qdict_put_str(output_opts, "server.port", port ?: stringify(22));
588 }
589
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;
609 }
610 }
611
612 return true;
613 }
614
615 static BlockdevOptionsSsh *ssh_parse_options(QDict *options, Error **errp)
616 {
617 BlockdevOptionsSsh *result = NULL;
618 QemuOpts *opts = NULL;
619 Error *local_err = NULL;
620 const QDictEntry *e;
621 Visitor *v;
622
623 /* Translate legacy options */
624 opts = qemu_opts_create(&ssh_runtime_opts, NULL, 0, &error_abort);
625 if (!qemu_opts_absorb_qdict(opts, options, errp)) {
626 goto fail;
627 }
628
629 if (!ssh_process_legacy_options(options, opts, errp)) {
630 goto fail;
631 }
632
633 /* Create the QAPI object */
634 v = qobject_input_visitor_new_flat_confused(options, errp);
635 if (!v) {
636 goto fail;
637 }
638
639 visit_type_BlockdevOptionsSsh(v, NULL, &result, &local_err);
640 visit_free(v);
641
642 if (local_err) {
643 error_propagate(errp, local_err);
644 goto fail;
645 }
646
647 /* Remove the processed options from the QDict (the visitor processes
648 * _all_ options in the QDict) */
649 while ((e = qdict_first(options))) {
650 qdict_del(options, e->key);
651 }
652
653 fail:
654 qemu_opts_del(opts);
655 return result;
656 }
657
658 static int connect_to_ssh(BDRVSSHState *s, BlockdevOptionsSsh *opts,
659 int ssh_flags, int creat_mode, Error **errp)
660 {
661 int r, ret;
662 unsigned int port = 0;
663 int new_sock = -1;
664
665 if (opts->has_user) {
666 s->user = g_strdup(opts->user);
667 } else {
668 s->user = g_strdup(g_get_user_name());
669 if (!s->user) {
670 error_setg_errno(errp, errno, "Can't get user name");
671 ret = -errno;
672 goto err;
673 }
674 }
675
676 /* Pop the config into our state object, Exit if invalid */
677 s->inet = opts->server;
678 opts->server = NULL;
679
680 if (qemu_strtoui(s->inet->port, NULL, 10, &port) < 0) {
681 error_setg(errp, "Use only numeric port value");
682 ret = -EINVAL;
683 goto err;
684 }
685
686 /* Open the socket and connect. */
687 new_sock = inet_connect_saddr(s->inet, errp);
688 if (new_sock < 0) {
689 ret = -EIO;
690 goto err;
691 }
692
693 /*
694 * Try to disable the Nagle algorithm on TCP sockets to reduce latency,
695 * but do not fail if it cannot be disabled.
696 */
697 r = socket_set_nodelay(new_sock);
698 if (r < 0) {
699 warn_report("can't set TCP_NODELAY for the ssh server %s: %s",
700 s->inet->host, strerror(errno));
701 }
702
703 /* Create SSH session. */
704 s->session = ssh_new();
705 if (!s->session) {
706 ret = -EINVAL;
707 session_error_setg(errp, s, "failed to initialize libssh session");
708 goto err;
709 }
710
711 /*
712 * Make sure we are in blocking mode during the connection and
713 * authentication phases.
714 */
715 ssh_set_blocking(s->session, 1);
716
717 r = ssh_options_set(s->session, SSH_OPTIONS_USER, s->user);
718 if (r < 0) {
719 ret = -EINVAL;
720 session_error_setg(errp, s,
721 "failed to set the user in the libssh session");
722 goto err;
723 }
724
725 r = ssh_options_set(s->session, SSH_OPTIONS_HOST, s->inet->host);
726 if (r < 0) {
727 ret = -EINVAL;
728 session_error_setg(errp, s,
729 "failed to set the host in the libssh session");
730 goto err;
731 }
732
733 if (port > 0) {
734 r = ssh_options_set(s->session, SSH_OPTIONS_PORT, &port);
735 if (r < 0) {
736 ret = -EINVAL;
737 session_error_setg(errp, s,
738 "failed to set the port in the libssh session");
739 goto err;
740 }
741 }
742
743 r = ssh_options_set(s->session, SSH_OPTIONS_COMPRESSION, "none");
744 if (r < 0) {
745 ret = -EINVAL;
746 session_error_setg(errp, s,
747 "failed to disable the compression in the libssh "
748 "session");
749 goto err;
750 }
751
752 /* Read ~/.ssh/config. */
753 r = ssh_options_parse_config(s->session, NULL);
754 if (r < 0) {
755 ret = -EINVAL;
756 session_error_setg(errp, s, "failed to parse ~/.ssh/config");
757 goto err;
758 }
759
760 r = ssh_options_set(s->session, SSH_OPTIONS_FD, &new_sock);
761 if (r < 0) {
762 ret = -EINVAL;
763 session_error_setg(errp, s,
764 "failed to set the socket in the libssh session");
765 goto err;
766 }
767 /* libssh took ownership of the socket. */
768 s->sock = new_sock;
769 new_sock = -1;
770
771 /* Connect. */
772 r = ssh_connect(s->session);
773 if (r != SSH_OK) {
774 ret = -EINVAL;
775 session_error_setg(errp, s, "failed to establish SSH session");
776 goto err;
777 }
778
779 /* Check the remote host's key against known_hosts. */
780 ret = check_host_key(s, opts->host_key_check, errp);
781 if (ret < 0) {
782 goto err;
783 }
784
785 /* Authenticate. */
786 ret = authenticate(s, errp);
787 if (ret < 0) {
788 goto err;
789 }
790
791 /* Start SFTP. */
792 s->sftp = sftp_new(s->session);
793 if (!s->sftp) {
794 session_error_setg(errp, s, "failed to create sftp handle");
795 ret = -EINVAL;
796 goto err;
797 }
798
799 r = sftp_init(s->sftp);
800 if (r < 0) {
801 sftp_error_setg(errp, s, "failed to initialize sftp handle");
802 ret = -EINVAL;
803 goto err;
804 }
805
806 /* Open the remote file. */
807 trace_ssh_connect_to_ssh(opts->path, ssh_flags, creat_mode);
808 s->sftp_handle = sftp_open(s->sftp, opts->path, ssh_flags, creat_mode);
809 if (!s->sftp_handle) {
810 sftp_error_setg(errp, s, "failed to open remote file '%s'",
811 opts->path);
812 ret = -EINVAL;
813 goto err;
814 }
815
816 /* Make sure the SFTP file is handled in blocking mode. */
817 sftp_file_set_blocking(s->sftp_handle);
818
819 s->attrs = sftp_fstat(s->sftp_handle);
820 if (!s->attrs) {
821 sftp_error_setg(errp, s, "failed to read file attributes");
822 return -EINVAL;
823 }
824
825 return 0;
826
827 err:
828 if (s->attrs) {
829 sftp_attributes_free(s->attrs);
830 }
831 s->attrs = NULL;
832 if (s->sftp_handle) {
833 sftp_close(s->sftp_handle);
834 }
835 s->sftp_handle = NULL;
836 if (s->sftp) {
837 sftp_free(s->sftp);
838 }
839 s->sftp = NULL;
840 if (s->session) {
841 ssh_disconnect(s->session);
842 ssh_free(s->session);
843 }
844 s->session = NULL;
845 s->sock = -1;
846 if (new_sock >= 0) {
847 close(new_sock);
848 }
849
850 return ret;
851 }
852
853 static int ssh_file_open(BlockDriverState *bs, QDict *options, int bdrv_flags,
854 Error **errp)
855 {
856 BDRVSSHState *s = bs->opaque;
857 BlockdevOptionsSsh *opts;
858 int ret;
859 int ssh_flags;
860
861 ssh_state_init(s);
862
863 ssh_flags = 0;
864 if (bdrv_flags & BDRV_O_RDWR) {
865 ssh_flags |= O_RDWR;
866 } else {
867 ssh_flags |= O_RDONLY;
868 }
869
870 opts = ssh_parse_options(options, errp);
871 if (opts == NULL) {
872 return -EINVAL;
873 }
874
875 /* Start up SSH. */
876 ret = connect_to_ssh(s, opts, ssh_flags, 0, errp);
877 if (ret < 0) {
878 goto err;
879 }
880
881 /* Go non-blocking. */
882 ssh_set_blocking(s->session, 0);
883
884 if (s->attrs->type == SSH_FILEXFER_TYPE_REGULAR) {
885 bs->supported_truncate_flags = BDRV_REQ_ZERO_WRITE;
886 }
887
888 qapi_free_BlockdevOptionsSsh(opts);
889
890 return 0;
891
892 err:
893 qapi_free_BlockdevOptionsSsh(opts);
894
895 return ret;
896 }
897
898 /* Note: This is a blocking operation */
899 static int ssh_grow_file(BDRVSSHState *s, int64_t offset, Error **errp)
900 {
901 ssize_t ret;
902 char c[1] = { '\0' };
903 int was_blocking = ssh_is_blocking(s->session);
904
905 /* offset must be strictly greater than the current size so we do
906 * not overwrite anything */
907 assert(offset > 0 && offset > s->attrs->size);
908
909 ssh_set_blocking(s->session, 1);
910
911 sftp_seek64(s->sftp_handle, offset - 1);
912 ret = sftp_write(s->sftp_handle, c, 1);
913
914 ssh_set_blocking(s->session, was_blocking);
915
916 if (ret < 0) {
917 sftp_error_setg(errp, s, "Failed to grow file");
918 return -EIO;
919 }
920
921 s->attrs->size = offset;
922 return 0;
923 }
924
925 static QemuOptsList ssh_create_opts = {
926 .name = "ssh-create-opts",
927 .head = QTAILQ_HEAD_INITIALIZER(ssh_create_opts.head),
928 .desc = {
929 {
930 .name = BLOCK_OPT_SIZE,
931 .type = QEMU_OPT_SIZE,
932 .help = "Virtual disk size"
933 },
934 { /* end of list */ }
935 }
936 };
937
938 static int ssh_co_create(BlockdevCreateOptions *options, Error **errp)
939 {
940 BlockdevCreateOptionsSsh *opts = &options->u.ssh;
941 BDRVSSHState s;
942 int ret;
943
944 assert(options->driver == BLOCKDEV_DRIVER_SSH);
945
946 ssh_state_init(&s);
947
948 ret = connect_to_ssh(&s, opts->location,
949 O_RDWR | O_CREAT | O_TRUNC,
950 0644, errp);
951 if (ret < 0) {
952 goto fail;
953 }
954
955 if (opts->size > 0) {
956 ret = ssh_grow_file(&s, opts->size, errp);
957 if (ret < 0) {
958 goto fail;
959 }
960 }
961
962 ret = 0;
963 fail:
964 ssh_state_free(&s);
965 return ret;
966 }
967
968 static int coroutine_fn ssh_co_create_opts(BlockDriver *drv,
969 const char *filename,
970 QemuOpts *opts,
971 Error **errp)
972 {
973 BlockdevCreateOptions *create_options;
974 BlockdevCreateOptionsSsh *ssh_opts;
975 int ret;
976 QDict *uri_options = NULL;
977
978 create_options = g_new0(BlockdevCreateOptions, 1);
979 create_options->driver = BLOCKDEV_DRIVER_SSH;
980 ssh_opts = &create_options->u.ssh;
981
982 /* Get desired file size. */
983 ssh_opts->size = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0),
984 BDRV_SECTOR_SIZE);
985 trace_ssh_co_create_opts(ssh_opts->size);
986
987 uri_options = qdict_new();
988 ret = parse_uri(filename, uri_options, errp);
989 if (ret < 0) {
990 goto out;
991 }
992
993 ssh_opts->location = ssh_parse_options(uri_options, errp);
994 if (ssh_opts->location == NULL) {
995 ret = -EINVAL;
996 goto out;
997 }
998
999 ret = ssh_co_create(create_options, errp);
1000
1001 out:
1002 qobject_unref(uri_options);
1003 qapi_free_BlockdevCreateOptions(create_options);
1004 return ret;
1005 }
1006
1007 static void ssh_close(BlockDriverState *bs)
1008 {
1009 BDRVSSHState *s = bs->opaque;
1010
1011 ssh_state_free(s);
1012 }
1013
1014 static int ssh_has_zero_init(BlockDriverState *bs)
1015 {
1016 BDRVSSHState *s = bs->opaque;
1017 /* Assume false, unless we can positively prove it's true. */
1018 int has_zero_init = 0;
1019
1020 if (s->attrs->type == SSH_FILEXFER_TYPE_REGULAR) {
1021 has_zero_init = 1;
1022 }
1023
1024 return has_zero_init;
1025 }
1026
1027 typedef struct BDRVSSHRestart {
1028 BlockDriverState *bs;
1029 Coroutine *co;
1030 } BDRVSSHRestart;
1031
1032 static void restart_coroutine(void *opaque)
1033 {
1034 BDRVSSHRestart *restart = opaque;
1035 BlockDriverState *bs = restart->bs;
1036 BDRVSSHState *s = bs->opaque;
1037 AioContext *ctx = bdrv_get_aio_context(bs);
1038
1039 trace_ssh_restart_coroutine(restart->co);
1040 aio_set_fd_handler(ctx, s->sock, false, NULL, NULL, NULL, NULL);
1041
1042 aio_co_wake(restart->co);
1043 }
1044
1045 /* A non-blocking call returned EAGAIN, so yield, ensuring the
1046 * handlers are set up so that we'll be rescheduled when there is an
1047 * interesting event on the socket.
1048 */
1049 static coroutine_fn void co_yield(BDRVSSHState *s, BlockDriverState *bs)
1050 {
1051 int r;
1052 IOHandler *rd_handler = NULL, *wr_handler = NULL;
1053 BDRVSSHRestart restart = {
1054 .bs = bs,
1055 .co = qemu_coroutine_self()
1056 };
1057
1058 r = ssh_get_poll_flags(s->session);
1059
1060 if (r & SSH_READ_PENDING) {
1061 rd_handler = restart_coroutine;
1062 }
1063 if (r & SSH_WRITE_PENDING) {
1064 wr_handler = restart_coroutine;
1065 }
1066
1067 trace_ssh_co_yield(s->sock, rd_handler, wr_handler);
1068
1069 aio_set_fd_handler(bdrv_get_aio_context(bs), s->sock,
1070 false, rd_handler, wr_handler, NULL, &restart);
1071 qemu_coroutine_yield();
1072 trace_ssh_co_yield_back(s->sock);
1073 }
1074
1075 static coroutine_fn int ssh_read(BDRVSSHState *s, BlockDriverState *bs,
1076 int64_t offset, size_t size,
1077 QEMUIOVector *qiov)
1078 {
1079 ssize_t r;
1080 size_t got;
1081 char *buf, *end_of_vec;
1082 struct iovec *i;
1083
1084 trace_ssh_read(offset, size);
1085
1086 trace_ssh_seek(offset);
1087 sftp_seek64(s->sftp_handle, offset);
1088
1089 /* This keeps track of the current iovec element ('i'), where we
1090 * will write to next ('buf'), and the end of the current iovec
1091 * ('end_of_vec').
1092 */
1093 i = &qiov->iov[0];
1094 buf = i->iov_base;
1095 end_of_vec = i->iov_base + i->iov_len;
1096
1097 for (got = 0; got < size; ) {
1098 size_t request_read_size;
1099 again:
1100 /*
1101 * The size of SFTP packets is limited to 32K bytes, so limit
1102 * the amount of data requested to 16K, as libssh currently
1103 * does not handle multiple requests on its own.
1104 */
1105 request_read_size = MIN(end_of_vec - buf, 16384);
1106 trace_ssh_read_buf(buf, end_of_vec - buf, request_read_size);
1107 r = sftp_read(s->sftp_handle, buf, request_read_size);
1108 trace_ssh_read_return(r, sftp_get_error(s->sftp));
1109
1110 if (r == SSH_AGAIN) {
1111 co_yield(s, bs);
1112 goto again;
1113 }
1114 if (r == SSH_EOF || (r == 0 && sftp_get_error(s->sftp) == SSH_FX_EOF)) {
1115 /* EOF: Short read so pad the buffer with zeroes and return it. */
1116 qemu_iovec_memset(qiov, got, 0, size - got);
1117 return 0;
1118 }
1119 if (r <= 0) {
1120 sftp_error_trace(s, "read");
1121 return -EIO;
1122 }
1123
1124 got += r;
1125 buf += r;
1126 if (buf >= end_of_vec && got < size) {
1127 i++;
1128 buf = i->iov_base;
1129 end_of_vec = i->iov_base + i->iov_len;
1130 }
1131 }
1132
1133 return 0;
1134 }
1135
1136 static coroutine_fn int ssh_co_readv(BlockDriverState *bs,
1137 int64_t sector_num,
1138 int nb_sectors, QEMUIOVector *qiov)
1139 {
1140 BDRVSSHState *s = bs->opaque;
1141 int ret;
1142
1143 qemu_co_mutex_lock(&s->lock);
1144 ret = ssh_read(s, bs, sector_num * BDRV_SECTOR_SIZE,
1145 nb_sectors * BDRV_SECTOR_SIZE, qiov);
1146 qemu_co_mutex_unlock(&s->lock);
1147
1148 return ret;
1149 }
1150
1151 static int ssh_write(BDRVSSHState *s, BlockDriverState *bs,
1152 int64_t offset, size_t size,
1153 QEMUIOVector *qiov)
1154 {
1155 ssize_t r;
1156 size_t written;
1157 char *buf, *end_of_vec;
1158 struct iovec *i;
1159
1160 trace_ssh_write(offset, size);
1161
1162 trace_ssh_seek(offset);
1163 sftp_seek64(s->sftp_handle, offset);
1164
1165 /* This keeps track of the current iovec element ('i'), where we
1166 * will read from next ('buf'), and the end of the current iovec
1167 * ('end_of_vec').
1168 */
1169 i = &qiov->iov[0];
1170 buf = i->iov_base;
1171 end_of_vec = i->iov_base + i->iov_len;
1172
1173 for (written = 0; written < size; ) {
1174 size_t request_write_size;
1175 again:
1176 /*
1177 * Avoid too large data packets, as libssh currently does not
1178 * handle multiple requests on its own.
1179 */
1180 request_write_size = MIN(end_of_vec - buf, 131072);
1181 trace_ssh_write_buf(buf, end_of_vec - buf, request_write_size);
1182 r = sftp_write(s->sftp_handle, buf, request_write_size);
1183 trace_ssh_write_return(r, sftp_get_error(s->sftp));
1184
1185 if (r == SSH_AGAIN) {
1186 co_yield(s, bs);
1187 goto again;
1188 }
1189 if (r < 0) {
1190 sftp_error_trace(s, "write");
1191 return -EIO;
1192 }
1193
1194 written += r;
1195 buf += r;
1196 if (buf >= end_of_vec && written < size) {
1197 i++;
1198 buf = i->iov_base;
1199 end_of_vec = i->iov_base + i->iov_len;
1200 }
1201
1202 if (offset + written > s->attrs->size) {
1203 s->attrs->size = offset + written;
1204 }
1205 }
1206
1207 return 0;
1208 }
1209
1210 static coroutine_fn int ssh_co_writev(BlockDriverState *bs,
1211 int64_t sector_num,
1212 int nb_sectors, QEMUIOVector *qiov,
1213 int flags)
1214 {
1215 BDRVSSHState *s = bs->opaque;
1216 int ret;
1217
1218 assert(!flags);
1219 qemu_co_mutex_lock(&s->lock);
1220 ret = ssh_write(s, bs, sector_num * BDRV_SECTOR_SIZE,
1221 nb_sectors * BDRV_SECTOR_SIZE, qiov);
1222 qemu_co_mutex_unlock(&s->lock);
1223
1224 return ret;
1225 }
1226
1227 static void unsafe_flush_warning(BDRVSSHState *s, const char *what)
1228 {
1229 if (!s->unsafe_flush_warning) {
1230 warn_report("ssh server %s does not support fsync",
1231 s->inet->host);
1232 if (what) {
1233 error_report("to support fsync, you need %s", what);
1234 }
1235 s->unsafe_flush_warning = true;
1236 }
1237 }
1238
1239 #ifdef HAVE_LIBSSH_0_8
1240
1241 static coroutine_fn int ssh_flush(BDRVSSHState *s, BlockDriverState *bs)
1242 {
1243 int r;
1244
1245 trace_ssh_flush();
1246
1247 if (!sftp_extension_supported(s->sftp, "fsync@openssh.com", "1")) {
1248 unsafe_flush_warning(s, "OpenSSH >= 6.3");
1249 return 0;
1250 }
1251 again:
1252 r = sftp_fsync(s->sftp_handle);
1253 if (r == SSH_AGAIN) {
1254 co_yield(s, bs);
1255 goto again;
1256 }
1257 if (r < 0) {
1258 sftp_error_trace(s, "fsync");
1259 return -EIO;
1260 }
1261
1262 return 0;
1263 }
1264
1265 static coroutine_fn int ssh_co_flush(BlockDriverState *bs)
1266 {
1267 BDRVSSHState *s = bs->opaque;
1268 int ret;
1269
1270 qemu_co_mutex_lock(&s->lock);
1271 ret = ssh_flush(s, bs);
1272 qemu_co_mutex_unlock(&s->lock);
1273
1274 return ret;
1275 }
1276
1277 #else /* !HAVE_LIBSSH_0_8 */
1278
1279 static coroutine_fn int ssh_co_flush(BlockDriverState *bs)
1280 {
1281 BDRVSSHState *s = bs->opaque;
1282
1283 unsafe_flush_warning(s, "libssh >= 0.8.0");
1284 return 0;
1285 }
1286
1287 #endif /* !HAVE_LIBSSH_0_8 */
1288
1289 static int64_t ssh_getlength(BlockDriverState *bs)
1290 {
1291 BDRVSSHState *s = bs->opaque;
1292 int64_t length;
1293
1294 /* Note we cannot make a libssh call here. */
1295 length = (int64_t) s->attrs->size;
1296 trace_ssh_getlength(length);
1297
1298 return length;
1299 }
1300
1301 static int coroutine_fn ssh_co_truncate(BlockDriverState *bs, int64_t offset,
1302 bool exact, PreallocMode prealloc,
1303 BdrvRequestFlags flags, Error **errp)
1304 {
1305 BDRVSSHState *s = bs->opaque;
1306
1307 if (prealloc != PREALLOC_MODE_OFF) {
1308 error_setg(errp, "Unsupported preallocation mode '%s'",
1309 PreallocMode_str(prealloc));
1310 return -ENOTSUP;
1311 }
1312
1313 if (offset < s->attrs->size) {
1314 error_setg(errp, "ssh driver does not support shrinking files");
1315 return -ENOTSUP;
1316 }
1317
1318 if (offset == s->attrs->size) {
1319 return 0;
1320 }
1321
1322 return ssh_grow_file(s, offset, errp);
1323 }
1324
1325 static void ssh_refresh_filename(BlockDriverState *bs)
1326 {
1327 BDRVSSHState *s = bs->opaque;
1328 const char *path, *host_key_check;
1329 int ret;
1330
1331 /*
1332 * None of these options can be represented in a plain "host:port"
1333 * format, so if any was given, we have to abort.
1334 */
1335 if (s->inet->has_ipv4 || s->inet->has_ipv6 || s->inet->has_to ||
1336 s->inet->has_numeric)
1337 {
1338 return;
1339 }
1340
1341 path = qdict_get_try_str(bs->full_open_options, "path");
1342 assert(path); /* mandatory option */
1343
1344 host_key_check = qdict_get_try_str(bs->full_open_options, "host_key_check");
1345
1346 ret = snprintf(bs->exact_filename, sizeof(bs->exact_filename),
1347 "ssh://%s@%s:%s%s%s%s",
1348 s->user, s->inet->host, s->inet->port, path,
1349 host_key_check ? "?host_key_check=" : "",
1350 host_key_check ?: "");
1351 if (ret >= sizeof(bs->exact_filename)) {
1352 /* An overflow makes the filename unusable, so do not report any */
1353 bs->exact_filename[0] = '\0';
1354 }
1355 }
1356
1357 static char *ssh_bdrv_dirname(BlockDriverState *bs, Error **errp)
1358 {
1359 if (qdict_haskey(bs->full_open_options, "host_key_check")) {
1360 /*
1361 * We cannot generate a simple prefix if we would have to
1362 * append a query string.
1363 */
1364 error_setg(errp,
1365 "Cannot generate a base directory with host_key_check set");
1366 return NULL;
1367 }
1368
1369 if (bs->exact_filename[0] == '\0') {
1370 error_setg(errp, "Cannot generate a base directory for this ssh node");
1371 return NULL;
1372 }
1373
1374 return path_combine(bs->exact_filename, "");
1375 }
1376
1377 static const char *const ssh_strong_runtime_opts[] = {
1378 "host",
1379 "port",
1380 "path",
1381 "user",
1382 "host_key_check",
1383 "server.",
1384
1385 NULL
1386 };
1387
1388 static BlockDriver bdrv_ssh = {
1389 .format_name = "ssh",
1390 .protocol_name = "ssh",
1391 .instance_size = sizeof(BDRVSSHState),
1392 .bdrv_parse_filename = ssh_parse_filename,
1393 .bdrv_file_open = ssh_file_open,
1394 .bdrv_co_create = ssh_co_create,
1395 .bdrv_co_create_opts = ssh_co_create_opts,
1396 .bdrv_close = ssh_close,
1397 .bdrv_has_zero_init = ssh_has_zero_init,
1398 .bdrv_co_readv = ssh_co_readv,
1399 .bdrv_co_writev = ssh_co_writev,
1400 .bdrv_getlength = ssh_getlength,
1401 .bdrv_co_truncate = ssh_co_truncate,
1402 .bdrv_co_flush_to_disk = ssh_co_flush,
1403 .bdrv_refresh_filename = ssh_refresh_filename,
1404 .bdrv_dirname = ssh_bdrv_dirname,
1405 .create_opts = &ssh_create_opts,
1406 .strong_runtime_opts = ssh_strong_runtime_opts,
1407 };
1408
1409 static void bdrv_ssh_init(void)
1410 {
1411 int r;
1412
1413 r = ssh_init();
1414 if (r != 0) {
1415 fprintf(stderr, "libssh initialization failed, %d\n", r);
1416 exit(EXIT_FAILURE);
1417 }
1418
1419 #if TRACE_LIBSSH != 0
1420 ssh_set_log_level(TRACE_LIBSSH);
1421 #endif
1422
1423 bdrv_register(&bdrv_ssh);
1424 }
1425
1426 block_init(bdrv_ssh_init);