qemu

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-io.h"
31
#include "block/block_int.h"
32
#include "block/qdict.h"
33
#include "qapi/error.h"
34
#include "qemu/error-report.h"
35
#include "qemu/module.h"
36
#include "qemu/option.h"
37
#include "qemu/ctype.h"
38
#include "qemu/cutils.h"
39
#include "qemu/sockets.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 G_GNUC_PRINTF(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 G_GNUC_PRINTF(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
    g_autoptr(GUri) uri = g_uri_parse(filename, G_URI_FLAGS_NONE, NULL);
184
    const char *uri_host, *uri_path, *uri_user, *uri_query;
185
    char *port_str;
186
    int port;
187
    g_autoptr(GError) gerror = NULL;
188
    char *qp_name, *qp_value;
189
    GUriParamsIter qp;
190

191
    if (!uri) {
192
        return -EINVAL;
193
    }
194

195
    if (g_strcmp0(g_uri_get_scheme(uri), "ssh") != 0) {
196
        error_setg(errp, "URI scheme must be 'ssh'");
197
        return -EINVAL;
198
    }
199

200
    uri_host = g_uri_get_host(uri);
201
    if (!uri_host || g_str_equal(uri_host, "")) {
202
        error_setg(errp, "missing hostname in URI");
203
        return -EINVAL;
204
    }
205

206
    uri_path = g_uri_get_path(uri);
207
    if (!uri_path || g_str_equal(uri_path, "")) {
208
        error_setg(errp, "missing remote path in URI");
209
        return -EINVAL;
210
    }
211

212
    uri_user = g_uri_get_user(uri);
213
    if (uri_user && !g_str_equal(uri_user, "")) {
214
        qdict_put_str(options, "user", uri_user);
215
    }
216

217
    qdict_put_str(options, "server.host", uri_host);
218

219
    port = g_uri_get_port(uri);
220
    port_str = g_strdup_printf("%d", port > 0 ? 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
    uri_query = g_uri_get_query(uri);
227
    if (uri_query) {
228
        g_uri_params_iter_init(&qp, uri_query, -1, "&", G_URI_PARAMS_NONE);
229
        while (g_uri_params_iter_next(&qp, &qp_name, &qp_value, &gerror)) {
230
            if (!qp_name || !qp_value || gerror) {
231
                warn_report("Failed to parse SSH URI parameters '%s'",
232
                            uri_query);
233
                break;
234
            }
235
            /*
236
             * Pick out the query parameters that we understand, and ignore
237
             * (or rather warn about) the rest.
238
             */
239
            if (g_str_equal(qp_name, "host_key_check")) {
240
                qdict_put_str(options, "host_key_check", qp_value);
241
            } else {
242
                warn_report("Unsupported parameter '%s' in URI", qp_name);
243
            }
244
        }
245
    }
246

247
    return 0;
248
}
249

250
static bool ssh_has_filename_options_conflict(QDict *options, Error **errp)
251
{
252
    const QDictEntry *qe;
253

254
    for (qe = qdict_first(options); qe; qe = qdict_next(options, qe)) {
255
        if (!strcmp(qe->key, "host") ||
256
            !strcmp(qe->key, "port") ||
257
            !strcmp(qe->key, "path") ||
258
            !strcmp(qe->key, "user") ||
259
            !strcmp(qe->key, "host_key_check") ||
260
            strstart(qe->key, "server.", NULL))
261
        {
262
            error_setg(errp, "Option '%s' cannot be used with a file name",
263
                       qe->key);
264
            return true;
265
        }
266
    }
267

268
    return false;
269
}
270

271
static void ssh_parse_filename(const char *filename, QDict *options,
272
                               Error **errp)
273
{
274
    if (ssh_has_filename_options_conflict(options, errp)) {
275
        return;
276
    }
277

278
    parse_uri(filename, options, errp);
279
}
280

281
static int check_host_key_knownhosts(BDRVSSHState *s, Error **errp)
282
{
283
    int ret;
284
    enum ssh_known_hosts_e state;
285
    int r;
286
    ssh_key pubkey;
287
    enum ssh_keytypes_e pubkey_type;
288
    unsigned char *server_hash = NULL;
289
    size_t server_hash_len;
290
    char *fingerprint = NULL;
291

292
    state = ssh_session_is_known_server(s->session);
293
    trace_ssh_server_status(state);
294

295
    switch (state) {
296
    case SSH_KNOWN_HOSTS_OK:
297
        /* OK */
298
        trace_ssh_check_host_key_knownhosts();
299
        break;
300
    case SSH_KNOWN_HOSTS_CHANGED:
301
        ret = -EINVAL;
302
        r = ssh_get_server_publickey(s->session, &pubkey);
303
        if (r == 0) {
304
            r = ssh_get_publickey_hash(pubkey, SSH_PUBLICKEY_HASH_SHA256,
305
                                       &server_hash, &server_hash_len);
306
            pubkey_type = ssh_key_type(pubkey);
307
            ssh_key_free(pubkey);
308
        }
309
        if (r == 0) {
310
            fingerprint = ssh_get_fingerprint_hash(SSH_PUBLICKEY_HASH_SHA256,
311
                                                   server_hash,
312
                                                   server_hash_len);
313
            ssh_clean_pubkey_hash(&server_hash);
314
        }
315
        if (fingerprint) {
316
            error_setg(errp,
317
                       "host key (%s key with fingerprint %s) does not match "
318
                       "the one in known_hosts; this may be a possible attack",
319
                       ssh_key_type_to_char(pubkey_type), fingerprint);
320
            ssh_string_free_char(fingerprint);
321
        } else  {
322
            error_setg(errp,
323
                       "host key does not match the one in known_hosts; this "
324
                       "may be a possible attack");
325
        }
326
        goto out;
327
    case SSH_KNOWN_HOSTS_OTHER:
328
        ret = -EINVAL;
329
        error_setg(errp,
330
                   "host key for this server not found, another type exists");
331
        goto out;
332
    case SSH_KNOWN_HOSTS_UNKNOWN:
333
        ret = -EINVAL;
334
        error_setg(errp, "no host key was found in known_hosts");
335
        goto out;
336
    case SSH_KNOWN_HOSTS_NOT_FOUND:
337
        ret = -ENOENT;
338
        error_setg(errp, "known_hosts file not found");
339
        goto out;
340
    case SSH_KNOWN_HOSTS_ERROR:
341
        ret = -EINVAL;
342
        error_setg(errp, "error while checking the host");
343
        goto out;
344
    default:
345
        ret = -EINVAL;
346
        error_setg(errp, "error while checking for known server (%d)", state);
347
        goto out;
348
    }
349

350
    /* known_hosts checking successful. */
351
    ret = 0;
352

353
 out:
354
    return ret;
355
}
356

357
static unsigned hex2decimal(char ch)
358
{
359
    if (ch >= '0' && ch <= '9') {
360
        return (ch - '0');
361
    } else if (ch >= 'a' && ch <= 'f') {
362
        return 10 + (ch - 'a');
363
    } else if (ch >= 'A' && ch <= 'F') {
364
        return 10 + (ch - 'A');
365
    }
366

367
    return -1;
368
}
369

370
/* Compare the binary fingerprint (hash of host key) with the
371
 * host_key_check parameter.
372
 */
373
static int compare_fingerprint(const unsigned char *fingerprint, size_t len,
374
                               const char *host_key_check)
375
{
376
    unsigned c;
377

378
    while (len > 0) {
379
        while (*host_key_check == ':')
380
            host_key_check++;
381
        if (!qemu_isxdigit(host_key_check[0]) ||
382
            !qemu_isxdigit(host_key_check[1]))
383
            return 1;
384
        c = hex2decimal(host_key_check[0]) * 16 +
385
            hex2decimal(host_key_check[1]);
386
        if (c - *fingerprint != 0)
387
            return c - *fingerprint;
388
        fingerprint++;
389
        len--;
390
        host_key_check += 2;
391
    }
392
    return *host_key_check - '\0';
393
}
394

395
static char *format_fingerprint(const unsigned char *fingerprint, size_t len)
396
{
397
    static const char *hex = "0123456789abcdef";
398
    char *ret = g_new0(char, (len * 2) + 1);
399
    for (size_t i = 0; i < len; i++) {
400
        ret[i * 2] = hex[((fingerprint[i] >> 4) & 0xf)];
401
        ret[(i * 2) + 1] = hex[(fingerprint[i] & 0xf)];
402
    }
403
    ret[len * 2] = '\0';
404
    return ret;
405
}
406

407
static int
408
check_host_key_hash(BDRVSSHState *s, const char *hash,
409
                    enum ssh_publickey_hash_type type, const char *typestr,
410
                    Error **errp)
411
{
412
    int r;
413
    ssh_key pubkey;
414
    unsigned char *server_hash;
415
    size_t server_hash_len;
416
    const char *keytype;
417

418
    r = ssh_get_server_publickey(s->session, &pubkey);
419
    if (r != SSH_OK) {
420
        session_error_setg(errp, s, "failed to read remote host key");
421
        return -EINVAL;
422
    }
423

424
    keytype = ssh_key_type_to_char(ssh_key_type(pubkey));
425

426
    r = ssh_get_publickey_hash(pubkey, type, &server_hash, &server_hash_len);
427
    ssh_key_free(pubkey);
428
    if (r != 0) {
429
        session_error_setg(errp, s,
430
                           "failed reading the hash of the server SSH key");
431
        return -EINVAL;
432
    }
433

434
    r = compare_fingerprint(server_hash, server_hash_len, hash);
435
    if (r != 0) {
436
        g_autofree char *server_fp = format_fingerprint(server_hash,
437
                                                        server_hash_len);
438
        error_setg(errp, "remote host %s key fingerprint '%s:%s' "
439
                   "does not match host_key_check '%s:%s'",
440
                   keytype, typestr, server_fp, typestr, hash);
441
        ssh_clean_pubkey_hash(&server_hash);
442
        return -EPERM;
443
    }
444
    ssh_clean_pubkey_hash(&server_hash);
445

446
    return 0;
447
}
448

449
static int check_host_key(BDRVSSHState *s, SshHostKeyCheck *hkc, Error **errp)
450
{
451
    SshHostKeyCheckMode mode;
452

453
    if (hkc) {
454
        mode = hkc->mode;
455
    } else {
456
        mode = SSH_HOST_KEY_CHECK_MODE_KNOWN_HOSTS;
457
    }
458

459
    switch (mode) {
460
    case SSH_HOST_KEY_CHECK_MODE_NONE:
461
        return 0;
462
    case SSH_HOST_KEY_CHECK_MODE_HASH:
463
        if (hkc->u.hash.type == SSH_HOST_KEY_CHECK_HASH_TYPE_MD5) {
464
            return check_host_key_hash(s, hkc->u.hash.hash,
465
                                       SSH_PUBLICKEY_HASH_MD5, "md5",
466
                                       errp);
467
        } else if (hkc->u.hash.type == SSH_HOST_KEY_CHECK_HASH_TYPE_SHA1) {
468
            return check_host_key_hash(s, hkc->u.hash.hash,
469
                                       SSH_PUBLICKEY_HASH_SHA1, "sha1",
470
                                       errp);
471
        } else if (hkc->u.hash.type == SSH_HOST_KEY_CHECK_HASH_TYPE_SHA256) {
472
            return check_host_key_hash(s, hkc->u.hash.hash,
473
                                       SSH_PUBLICKEY_HASH_SHA256, "sha256",
474
                                       errp);
475
        }
476
        g_assert_not_reached();
477
        break;
478
    case SSH_HOST_KEY_CHECK_MODE_KNOWN_HOSTS:
479
        return check_host_key_knownhosts(s, errp);
480
    default:
481
        g_assert_not_reached();
482
    }
483

484
    return -EINVAL;
485
}
486

487
static int authenticate(BDRVSSHState *s, Error **errp)
488
{
489
    int r, ret;
490
    int method;
491

492
    /* Try to authenticate with the "none" method. */
493
    r = ssh_userauth_none(s->session, NULL);
494
    if (r == SSH_AUTH_ERROR) {
495
        ret = -EPERM;
496
        session_error_setg(errp, s, "failed to authenticate using none "
497
                                    "authentication");
498
        goto out;
499
    } else if (r == SSH_AUTH_SUCCESS) {
500
        /* Authenticated! */
501
        ret = 0;
502
        goto out;
503
    }
504

505
    method = ssh_userauth_list(s->session, NULL);
506
    trace_ssh_auth_methods(method);
507

508
    /*
509
     * Try to authenticate with publickey, using the ssh-agent
510
     * if available.
511
     */
512
    if (method & SSH_AUTH_METHOD_PUBLICKEY) {
513
        r = ssh_userauth_publickey_auto(s->session, NULL, NULL);
514
        if (r == SSH_AUTH_ERROR) {
515
            ret = -EINVAL;
516
            session_error_setg(errp, s, "failed to authenticate using "
517
                                        "publickey authentication");
518
            goto out;
519
        } else if (r == SSH_AUTH_SUCCESS) {
520
            /* Authenticated! */
521
            ret = 0;
522
            goto out;
523
        }
524
    }
525

526
    ret = -EPERM;
527
    error_setg(errp, "failed to authenticate using publickey authentication "
528
               "and the identities held by your ssh-agent");
529

530
 out:
531
    return ret;
532
}
533

534
static QemuOptsList ssh_runtime_opts = {
535
    .name = "ssh",
536
    .head = QTAILQ_HEAD_INITIALIZER(ssh_runtime_opts.head),
537
    .desc = {
538
        {
539
            .name = "host",
540
            .type = QEMU_OPT_STRING,
541
            .help = "Host to connect to",
542
        },
543
        {
544
            .name = "port",
545
            .type = QEMU_OPT_NUMBER,
546
            .help = "Port to connect to",
547
        },
548
        {
549
            .name = "host_key_check",
550
            .type = QEMU_OPT_STRING,
551
            .help = "Defines how and what to check the host key against",
552
        },
553
        { /* end of list */ }
554
    },
555
};
556

557
static bool ssh_process_legacy_options(QDict *output_opts,
558
                                       QemuOpts *legacy_opts,
559
                                       Error **errp)
560
{
561
    const char *host = qemu_opt_get(legacy_opts, "host");
562
    const char *port = qemu_opt_get(legacy_opts, "port");
563
    const char *host_key_check = qemu_opt_get(legacy_opts, "host_key_check");
564

565
    if (!host && port) {
566
        error_setg(errp, "port may not be used without host");
567
        return false;
568
    }
569

570
    if (host) {
571
        qdict_put_str(output_opts, "server.host", host);
572
        qdict_put_str(output_opts, "server.port", port ?: stringify(22));
573
    }
574

575
    if (host_key_check) {
576
        if (strcmp(host_key_check, "no") == 0) {
577
            qdict_put_str(output_opts, "host-key-check.mode", "none");
578
        } else if (strncmp(host_key_check, "md5:", 4) == 0) {
579
            qdict_put_str(output_opts, "host-key-check.mode", "hash");
580
            qdict_put_str(output_opts, "host-key-check.type", "md5");
581
            qdict_put_str(output_opts, "host-key-check.hash",
582
                          &host_key_check[4]);
583
        } else if (strncmp(host_key_check, "sha1:", 5) == 0) {
584
            qdict_put_str(output_opts, "host-key-check.mode", "hash");
585
            qdict_put_str(output_opts, "host-key-check.type", "sha1");
586
            qdict_put_str(output_opts, "host-key-check.hash",
587
                          &host_key_check[5]);
588
        } else if (strncmp(host_key_check, "sha256:", 7) == 0) {
589
            qdict_put_str(output_opts, "host-key-check.mode", "hash");
590
            qdict_put_str(output_opts, "host-key-check.type", "sha256");
591
            qdict_put_str(output_opts, "host-key-check.hash",
592
                          &host_key_check[7]);
593
        } else if (strcmp(host_key_check, "yes") == 0) {
594
            qdict_put_str(output_opts, "host-key-check.mode", "known_hosts");
595
        } else {
596
            error_setg(errp, "unknown host_key_check setting (%s)",
597
                       host_key_check);
598
            return false;
599
        }
600
    }
601

602
    return true;
603
}
604

605
static BlockdevOptionsSsh *ssh_parse_options(QDict *options, Error **errp)
606
{
607
    BlockdevOptionsSsh *result = NULL;
608
    QemuOpts *opts = NULL;
609
    const QDictEntry *e;
610
    Visitor *v;
611

612
    /* Translate legacy options */
613
    opts = qemu_opts_create(&ssh_runtime_opts, NULL, 0, &error_abort);
614
    if (!qemu_opts_absorb_qdict(opts, options, errp)) {
615
        goto fail;
616
    }
617

618
    if (!ssh_process_legacy_options(options, opts, errp)) {
619
        goto fail;
620
    }
621

622
    /* Create the QAPI object */
623
    v = qobject_input_visitor_new_flat_confused(options, errp);
624
    if (!v) {
625
        goto fail;
626
    }
627

628
    visit_type_BlockdevOptionsSsh(v, NULL, &result, errp);
629
    visit_free(v);
630
    if (!result) {
631
        goto fail;
632
    }
633

634
    /* Remove the processed options from the QDict (the visitor processes
635
     * _all_ options in the QDict) */
636
    while ((e = qdict_first(options))) {
637
        qdict_del(options, e->key);
638
    }
639

640
fail:
641
    qemu_opts_del(opts);
642
    return result;
643
}
644

645
static int connect_to_ssh(BDRVSSHState *s, BlockdevOptionsSsh *opts,
646
                          int ssh_flags, int creat_mode, Error **errp)
647
{
648
    int r, ret;
649
    unsigned int port = 0;
650
    int new_sock = -1;
651

652
    if (opts->user) {
653
        s->user = g_strdup(opts->user);
654
    } else {
655
        s->user = g_strdup(g_get_user_name());
656
        if (!s->user) {
657
            error_setg_errno(errp, errno, "Can't get user name");
658
            ret = -errno;
659
            goto err;
660
        }
661
    }
662

663
    /* Pop the config into our state object, Exit if invalid */
664
    s->inet = opts->server;
665
    opts->server = NULL;
666

667
    if (qemu_strtoui(s->inet->port, NULL, 10, &port) < 0) {
668
        error_setg(errp, "Use only numeric port value");
669
        ret = -EINVAL;
670
        goto err;
671
    }
672

673
    /* Open the socket and connect. */
674
    new_sock = inet_connect_saddr(s->inet, errp);
675
    if (new_sock < 0) {
676
        ret = -EIO;
677
        goto err;
678
    }
679

680
    /*
681
     * Try to disable the Nagle algorithm on TCP sockets to reduce latency,
682
     * but do not fail if it cannot be disabled.
683
     */
684
    r = socket_set_nodelay(new_sock);
685
    if (r < 0) {
686
        warn_report("can't set TCP_NODELAY for the ssh server %s: %s",
687
                    s->inet->host, strerror(errno));
688
    }
689

690
    /* Create SSH session. */
691
    s->session = ssh_new();
692
    if (!s->session) {
693
        ret = -EINVAL;
694
        session_error_setg(errp, s, "failed to initialize libssh session");
695
        goto err;
696
    }
697

698
    /*
699
     * Make sure we are in blocking mode during the connection and
700
     * authentication phases.
701
     */
702
    ssh_set_blocking(s->session, 1);
703

704
    r = ssh_options_set(s->session, SSH_OPTIONS_USER, s->user);
705
    if (r < 0) {
706
        ret = -EINVAL;
707
        session_error_setg(errp, s,
708
                           "failed to set the user in the libssh session");
709
        goto err;
710
    }
711

712
    r = ssh_options_set(s->session, SSH_OPTIONS_HOST, s->inet->host);
713
    if (r < 0) {
714
        ret = -EINVAL;
715
        session_error_setg(errp, s,
716
                           "failed to set the host in the libssh session");
717
        goto err;
718
    }
719

720
    if (port > 0) {
721
        r = ssh_options_set(s->session, SSH_OPTIONS_PORT, &port);
722
        if (r < 0) {
723
            ret = -EINVAL;
724
            session_error_setg(errp, s,
725
                               "failed to set the port in the libssh session");
726
            goto err;
727
        }
728
    }
729

730
    r = ssh_options_set(s->session, SSH_OPTIONS_COMPRESSION, "none");
731
    if (r < 0) {
732
        ret = -EINVAL;
733
        session_error_setg(errp, s,
734
                           "failed to disable the compression in the libssh "
735
                           "session");
736
        goto err;
737
    }
738

739
    /* Read ~/.ssh/config. */
740
    r = ssh_options_parse_config(s->session, NULL);
741
    if (r < 0) {
742
        ret = -EINVAL;
743
        session_error_setg(errp, s, "failed to parse ~/.ssh/config");
744
        goto err;
745
    }
746

747
    r = ssh_options_set(s->session, SSH_OPTIONS_FD, &new_sock);
748
    if (r < 0) {
749
        ret = -EINVAL;
750
        session_error_setg(errp, s,
751
                           "failed to set the socket in the libssh session");
752
        goto err;
753
    }
754
    /* libssh took ownership of the socket. */
755
    s->sock = new_sock;
756
    new_sock = -1;
757

758
    /* Connect. */
759
    r = ssh_connect(s->session);
760
    if (r != SSH_OK) {
761
        ret = -EINVAL;
762
        session_error_setg(errp, s, "failed to establish SSH session");
763
        goto err;
764
    }
765

766
    /* Check the remote host's key against known_hosts. */
767
    ret = check_host_key(s, opts->host_key_check, errp);
768
    if (ret < 0) {
769
        goto err;
770
    }
771

772
    /* Authenticate. */
773
    ret = authenticate(s, errp);
774
    if (ret < 0) {
775
        goto err;
776
    }
777

778
    /* Start SFTP. */
779
    s->sftp = sftp_new(s->session);
780
    if (!s->sftp) {
781
        session_error_setg(errp, s, "failed to create sftp handle");
782
        ret = -EINVAL;
783
        goto err;
784
    }
785

786
    r = sftp_init(s->sftp);
787
    if (r < 0) {
788
        sftp_error_setg(errp, s, "failed to initialize sftp handle");
789
        ret = -EINVAL;
790
        goto err;
791
    }
792

793
    /* Open the remote file. */
794
    trace_ssh_connect_to_ssh(opts->path, ssh_flags, creat_mode);
795
    s->sftp_handle = sftp_open(s->sftp, opts->path, ssh_flags, creat_mode);
796
    if (!s->sftp_handle) {
797
        sftp_error_setg(errp, s, "failed to open remote file '%s'",
798
                        opts->path);
799
        ret = -EINVAL;
800
        goto err;
801
    }
802

803
    /* Make sure the SFTP file is handled in blocking mode. */
804
    sftp_file_set_blocking(s->sftp_handle);
805

806
    s->attrs = sftp_fstat(s->sftp_handle);
807
    if (!s->attrs) {
808
        sftp_error_setg(errp, s, "failed to read file attributes");
809
        return -EINVAL;
810
    }
811

812
    return 0;
813

814
 err:
815
    if (s->attrs) {
816
        sftp_attributes_free(s->attrs);
817
    }
818
    s->attrs = NULL;
819
    if (s->sftp_handle) {
820
        sftp_close(s->sftp_handle);
821
    }
822
    s->sftp_handle = NULL;
823
    if (s->sftp) {
824
        sftp_free(s->sftp);
825
    }
826
    s->sftp = NULL;
827
    if (s->session) {
828
        ssh_disconnect(s->session);
829
        ssh_free(s->session);
830
    }
831
    s->session = NULL;
832
    s->sock = -1;
833
    if (new_sock >= 0) {
834
        close(new_sock);
835
    }
836

837
    return ret;
838
}
839

840
static int ssh_open(BlockDriverState *bs, QDict *options, int bdrv_flags,
841
                    Error **errp)
842
{
843
    BDRVSSHState *s = bs->opaque;
844
    BlockdevOptionsSsh *opts;
845
    int ret;
846
    int ssh_flags;
847

848
    ssh_state_init(s);
849

850
    ssh_flags = 0;
851
    if (bdrv_flags & BDRV_O_RDWR) {
852
        ssh_flags |= O_RDWR;
853
    } else {
854
        ssh_flags |= O_RDONLY;
855
    }
856

857
    opts = ssh_parse_options(options, errp);
858
    if (opts == NULL) {
859
        return -EINVAL;
860
    }
861

862
    /* Start up SSH. */
863
    ret = connect_to_ssh(s, opts, ssh_flags, 0, errp);
864
    if (ret < 0) {
865
        goto err;
866
    }
867

868
    /* Go non-blocking. */
869
    ssh_set_blocking(s->session, 0);
870

871
    if (s->attrs->type == SSH_FILEXFER_TYPE_REGULAR) {
872
        bs->supported_truncate_flags = BDRV_REQ_ZERO_WRITE;
873
    }
874

875
    qapi_free_BlockdevOptionsSsh(opts);
876

877
    return 0;
878

879
 err:
880
    qapi_free_BlockdevOptionsSsh(opts);
881

882
    return ret;
883
}
884

885
/* Note: This is a blocking operation */
886
static int ssh_grow_file(BDRVSSHState *s, int64_t offset, Error **errp)
887
{
888
    ssize_t ret;
889
    char c[1] = { '\0' };
890
    int was_blocking = ssh_is_blocking(s->session);
891

892
    /* offset must be strictly greater than the current size so we do
893
     * not overwrite anything */
894
    assert(offset > 0 && offset > s->attrs->size);
895

896
    ssh_set_blocking(s->session, 1);
897

898
    sftp_seek64(s->sftp_handle, offset - 1);
899
    ret = sftp_write(s->sftp_handle, c, 1);
900

901
    ssh_set_blocking(s->session, was_blocking);
902

903
    if (ret < 0) {
904
        sftp_error_setg(errp, s, "Failed to grow file");
905
        return -EIO;
906
    }
907

908
    s->attrs->size = offset;
909
    return 0;
910
}
911

912
static QemuOptsList ssh_create_opts = {
913
    .name = "ssh-create-opts",
914
    .head = QTAILQ_HEAD_INITIALIZER(ssh_create_opts.head),
915
    .desc = {
916
        {
917
            .name = BLOCK_OPT_SIZE,
918
            .type = QEMU_OPT_SIZE,
919
            .help = "Virtual disk size"
920
        },
921
        { /* end of list */ }
922
    }
923
};
924

925
static int ssh_co_create(BlockdevCreateOptions *options, Error **errp)
926
{
927
    BlockdevCreateOptionsSsh *opts = &options->u.ssh;
928
    BDRVSSHState s;
929
    int ret;
930

931
    assert(options->driver == BLOCKDEV_DRIVER_SSH);
932

933
    ssh_state_init(&s);
934

935
    ret = connect_to_ssh(&s, opts->location,
936
                         O_RDWR | O_CREAT | O_TRUNC,
937
                         0644, errp);
938
    if (ret < 0) {
939
        goto fail;
940
    }
941

942
    if (opts->size > 0) {
943
        ret = ssh_grow_file(&s, opts->size, errp);
944
        if (ret < 0) {
945
            goto fail;
946
        }
947
    }
948

949
    ret = 0;
950
fail:
951
    ssh_state_free(&s);
952
    return ret;
953
}
954

955
static int coroutine_fn ssh_co_create_opts(BlockDriver *drv,
956
                                           const char *filename,
957
                                           QemuOpts *opts,
958
                                           Error **errp)
959
{
960
    BlockdevCreateOptions *create_options;
961
    BlockdevCreateOptionsSsh *ssh_opts;
962
    int ret;
963
    QDict *uri_options = NULL;
964

965
    create_options = g_new0(BlockdevCreateOptions, 1);
966
    create_options->driver = BLOCKDEV_DRIVER_SSH;
967
    ssh_opts = &create_options->u.ssh;
968

969
    /* Get desired file size. */
970
    ssh_opts->size = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0),
971
                              BDRV_SECTOR_SIZE);
972
    trace_ssh_co_create_opts(ssh_opts->size);
973

974
    uri_options = qdict_new();
975
    ret = parse_uri(filename, uri_options, errp);
976
    if (ret < 0) {
977
        goto out;
978
    }
979

980
    ssh_opts->location = ssh_parse_options(uri_options, errp);
981
    if (ssh_opts->location == NULL) {
982
        ret = -EINVAL;
983
        goto out;
984
    }
985

986
    ret = ssh_co_create(create_options, errp);
987

988
 out:
989
    qobject_unref(uri_options);
990
    qapi_free_BlockdevCreateOptions(create_options);
991
    return ret;
992
}
993

994
static void ssh_close(BlockDriverState *bs)
995
{
996
    BDRVSSHState *s = bs->opaque;
997

998
    ssh_state_free(s);
999
}
1000

1001
static int ssh_has_zero_init(BlockDriverState *bs)
1002
{
1003
    BDRVSSHState *s = bs->opaque;
1004
    /* Assume false, unless we can positively prove it's true. */
1005
    int has_zero_init = 0;
1006

1007
    if (s->attrs->type == SSH_FILEXFER_TYPE_REGULAR) {
1008
        has_zero_init = 1;
1009
    }
1010

1011
    return has_zero_init;
1012
}
1013

1014
typedef struct BDRVSSHRestart {
1015
    BlockDriverState *bs;
1016
    Coroutine *co;
1017
} BDRVSSHRestart;
1018

1019
static void restart_coroutine(void *opaque)
1020
{
1021
    BDRVSSHRestart *restart = opaque;
1022
    BlockDriverState *bs = restart->bs;
1023
    BDRVSSHState *s = bs->opaque;
1024
    AioContext *ctx = bdrv_get_aio_context(bs);
1025

1026
    trace_ssh_restart_coroutine(restart->co);
1027
    aio_set_fd_handler(ctx, s->sock, NULL, NULL, NULL, NULL, NULL);
1028

1029
    aio_co_wake(restart->co);
1030
}
1031

1032
/* A non-blocking call returned EAGAIN, so yield, ensuring the
1033
 * handlers are set up so that we'll be rescheduled when there is an
1034
 * interesting event on the socket.
1035
 */
1036
static coroutine_fn void co_yield(BDRVSSHState *s, BlockDriverState *bs)
1037
{
1038
    int r;
1039
    IOHandler *rd_handler = NULL, *wr_handler = NULL;
1040
    BDRVSSHRestart restart = {
1041
        .bs = bs,
1042
        .co = qemu_coroutine_self()
1043
    };
1044

1045
    r = ssh_get_poll_flags(s->session);
1046

1047
    if (r & SSH_READ_PENDING) {
1048
        rd_handler = restart_coroutine;
1049
    }
1050
    if (r & SSH_WRITE_PENDING) {
1051
        wr_handler = restart_coroutine;
1052
    }
1053

1054
    trace_ssh_co_yield(s->sock, rd_handler, wr_handler);
1055

1056
    aio_set_fd_handler(bdrv_get_aio_context(bs), s->sock,
1057
                       rd_handler, wr_handler, NULL, NULL, &restart);
1058
    qemu_coroutine_yield();
1059
    trace_ssh_co_yield_back(s->sock);
1060
}
1061

1062
static coroutine_fn int ssh_read(BDRVSSHState *s, BlockDriverState *bs,
1063
                                 int64_t offset, size_t size,
1064
                                 QEMUIOVector *qiov)
1065
{
1066
    ssize_t r;
1067
    size_t got;
1068
    char *buf, *end_of_vec;
1069
    struct iovec *i;
1070

1071
    trace_ssh_read(offset, size);
1072

1073
    trace_ssh_seek(offset);
1074
    sftp_seek64(s->sftp_handle, offset);
1075

1076
    /* This keeps track of the current iovec element ('i'), where we
1077
     * will write to next ('buf'), and the end of the current iovec
1078
     * ('end_of_vec').
1079
     */
1080
    i = &qiov->iov[0];
1081
    buf = i->iov_base;
1082
    end_of_vec = i->iov_base + i->iov_len;
1083

1084
    for (got = 0; got < size; ) {
1085
        size_t request_read_size;
1086
    again:
1087
        /*
1088
         * The size of SFTP packets is limited to 32K bytes, so limit
1089
         * the amount of data requested to 16K, as libssh currently
1090
         * does not handle multiple requests on its own.
1091
         */
1092
        request_read_size = MIN(end_of_vec - buf, 16384);
1093
        trace_ssh_read_buf(buf, end_of_vec - buf, request_read_size);
1094
        r = sftp_read(s->sftp_handle, buf, request_read_size);
1095
        trace_ssh_read_return(r, sftp_get_error(s->sftp));
1096

1097
        if (r == SSH_AGAIN) {
1098
            co_yield(s, bs);
1099
            goto again;
1100
        }
1101
        if (r == SSH_EOF || (r == 0 && sftp_get_error(s->sftp) == SSH_FX_EOF)) {
1102
            /* EOF: Short read so pad the buffer with zeroes and return it. */
1103
            qemu_iovec_memset(qiov, got, 0, size - got);
1104
            return 0;
1105
        }
1106
        if (r <= 0) {
1107
            sftp_error_trace(s, "read");
1108
            return -EIO;
1109
        }
1110

1111
        got += r;
1112
        buf += r;
1113
        if (buf >= end_of_vec && got < size) {
1114
            i++;
1115
            buf = i->iov_base;
1116
            end_of_vec = i->iov_base + i->iov_len;
1117
        }
1118
    }
1119

1120
    return 0;
1121
}
1122

1123
static coroutine_fn int ssh_co_readv(BlockDriverState *bs,
1124
                                     int64_t sector_num,
1125
                                     int nb_sectors, QEMUIOVector *qiov)
1126
{
1127
    BDRVSSHState *s = bs->opaque;
1128
    int ret;
1129

1130
    qemu_co_mutex_lock(&s->lock);
1131
    ret = ssh_read(s, bs, sector_num * BDRV_SECTOR_SIZE,
1132
                   nb_sectors * BDRV_SECTOR_SIZE, qiov);
1133
    qemu_co_mutex_unlock(&s->lock);
1134

1135
    return ret;
1136
}
1137

1138
static coroutine_fn int ssh_write(BDRVSSHState *s, BlockDriverState *bs,
1139
                                  int64_t offset, size_t size,
1140
                                  QEMUIOVector *qiov)
1141
{
1142
    ssize_t r;
1143
    size_t written;
1144
    char *buf, *end_of_vec;
1145
    struct iovec *i;
1146

1147
    trace_ssh_write(offset, size);
1148

1149
    trace_ssh_seek(offset);
1150
    sftp_seek64(s->sftp_handle, offset);
1151

1152
    /* This keeps track of the current iovec element ('i'), where we
1153
     * will read from next ('buf'), and the end of the current iovec
1154
     * ('end_of_vec').
1155
     */
1156
    i = &qiov->iov[0];
1157
    buf = i->iov_base;
1158
    end_of_vec = i->iov_base + i->iov_len;
1159

1160
    for (written = 0; written < size; ) {
1161
        size_t request_write_size;
1162
    again:
1163
        /*
1164
         * Avoid too large data packets, as libssh currently does not
1165
         * handle multiple requests on its own.
1166
         */
1167
        request_write_size = MIN(end_of_vec - buf, 131072);
1168
        trace_ssh_write_buf(buf, end_of_vec - buf, request_write_size);
1169
        r = sftp_write(s->sftp_handle, buf, request_write_size);
1170
        trace_ssh_write_return(r, sftp_get_error(s->sftp));
1171

1172
        if (r == SSH_AGAIN) {
1173
            co_yield(s, bs);
1174
            goto again;
1175
        }
1176
        if (r < 0) {
1177
            sftp_error_trace(s, "write");
1178
            return -EIO;
1179
        }
1180

1181
        written += r;
1182
        buf += r;
1183
        if (buf >= end_of_vec && written < size) {
1184
            i++;
1185
            buf = i->iov_base;
1186
            end_of_vec = i->iov_base + i->iov_len;
1187
        }
1188

1189
        if (offset + written > s->attrs->size) {
1190
            s->attrs->size = offset + written;
1191
        }
1192
    }
1193

1194
    return 0;
1195
}
1196

1197
static coroutine_fn int ssh_co_writev(BlockDriverState *bs,
1198
                                      int64_t sector_num,
1199
                                      int nb_sectors, QEMUIOVector *qiov,
1200
                                      int flags)
1201
{
1202
    BDRVSSHState *s = bs->opaque;
1203
    int ret;
1204

1205
    qemu_co_mutex_lock(&s->lock);
1206
    ret = ssh_write(s, bs, sector_num * BDRV_SECTOR_SIZE,
1207
                    nb_sectors * BDRV_SECTOR_SIZE, qiov);
1208
    qemu_co_mutex_unlock(&s->lock);
1209

1210
    return ret;
1211
}
1212

1213
static void unsafe_flush_warning(BDRVSSHState *s, const char *what)
1214
{
1215
    if (!s->unsafe_flush_warning) {
1216
        warn_report("ssh server %s does not support fsync",
1217
                    s->inet->host);
1218
        if (what) {
1219
            error_report("to support fsync, you need %s", what);
1220
        }
1221
        s->unsafe_flush_warning = true;
1222
    }
1223
}
1224

1225
static coroutine_fn int ssh_flush(BDRVSSHState *s, BlockDriverState *bs)
1226
{
1227
    int r;
1228

1229
    trace_ssh_flush();
1230

1231
    if (!sftp_extension_supported(s->sftp, "fsync@openssh.com", "1")) {
1232
        unsafe_flush_warning(s, "OpenSSH >= 6.3");
1233
        return 0;
1234
    }
1235
 again:
1236
    r = sftp_fsync(s->sftp_handle);
1237
    if (r == SSH_AGAIN) {
1238
        co_yield(s, bs);
1239
        goto again;
1240
    }
1241
    if (r < 0) {
1242
        sftp_error_trace(s, "fsync");
1243
        return -EIO;
1244
    }
1245

1246
    return 0;
1247
}
1248

1249
static coroutine_fn int ssh_co_flush(BlockDriverState *bs)
1250
{
1251
    BDRVSSHState *s = bs->opaque;
1252
    int ret;
1253

1254
    qemu_co_mutex_lock(&s->lock);
1255
    ret = ssh_flush(s, bs);
1256
    qemu_co_mutex_unlock(&s->lock);
1257

1258
    return ret;
1259
}
1260

1261
static int64_t coroutine_fn ssh_co_getlength(BlockDriverState *bs)
1262
{
1263
    BDRVSSHState *s = bs->opaque;
1264
    int64_t length;
1265

1266
    /* Note we cannot make a libssh call here. */
1267
    length = (int64_t) s->attrs->size;
1268
    trace_ssh_getlength(length);
1269

1270
    return length;
1271
}
1272

1273
static int coroutine_fn ssh_co_truncate(BlockDriverState *bs, int64_t offset,
1274
                                        bool exact, PreallocMode prealloc,
1275
                                        BdrvRequestFlags flags, Error **errp)
1276
{
1277
    BDRVSSHState *s = bs->opaque;
1278

1279
    if (prealloc != PREALLOC_MODE_OFF) {
1280
        error_setg(errp, "Unsupported preallocation mode '%s'",
1281
                   PreallocMode_str(prealloc));
1282
        return -ENOTSUP;
1283
    }
1284

1285
    if (offset < s->attrs->size) {
1286
        error_setg(errp, "ssh driver does not support shrinking files");
1287
        return -ENOTSUP;
1288
    }
1289

1290
    if (offset == s->attrs->size) {
1291
        return 0;
1292
    }
1293

1294
    return ssh_grow_file(s, offset, errp);
1295
}
1296

1297
static void ssh_refresh_filename(BlockDriverState *bs)
1298
{
1299
    BDRVSSHState *s = bs->opaque;
1300
    const char *path, *host_key_check;
1301
    int ret;
1302

1303
    /*
1304
     * None of these options can be represented in a plain "host:port"
1305
     * format, so if any was given, we have to abort.
1306
     */
1307
    if (s->inet->has_ipv4 || s->inet->has_ipv6 || s->inet->has_to ||
1308
        s->inet->has_numeric)
1309
    {
1310
        return;
1311
    }
1312

1313
    path = qdict_get_try_str(bs->full_open_options, "path");
1314
    assert(path); /* mandatory option */
1315

1316
    host_key_check = qdict_get_try_str(bs->full_open_options, "host_key_check");
1317

1318
    ret = snprintf(bs->exact_filename, sizeof(bs->exact_filename),
1319
                   "ssh://%s@%s:%s%s%s%s",
1320
                   s->user, s->inet->host, s->inet->port, path,
1321
                   host_key_check ? "?host_key_check=" : "",
1322
                   host_key_check ?: "");
1323
    if (ret >= sizeof(bs->exact_filename)) {
1324
        /* An overflow makes the filename unusable, so do not report any */
1325
        bs->exact_filename[0] = '\0';
1326
    }
1327
}
1328

1329
static char *ssh_bdrv_dirname(BlockDriverState *bs, Error **errp)
1330
{
1331
    if (qdict_haskey(bs->full_open_options, "host_key_check")) {
1332
        /*
1333
         * We cannot generate a simple prefix if we would have to
1334
         * append a query string.
1335
         */
1336
        error_setg(errp,
1337
                   "Cannot generate a base directory with host_key_check set");
1338
        return NULL;
1339
    }
1340

1341
    if (bs->exact_filename[0] == '\0') {
1342
        error_setg(errp, "Cannot generate a base directory for this ssh node");
1343
        return NULL;
1344
    }
1345

1346
    return path_combine(bs->exact_filename, "");
1347
}
1348

1349
static const char *const ssh_strong_runtime_opts[] = {
1350
    "host",
1351
    "port",
1352
    "path",
1353
    "user",
1354
    "host_key_check",
1355
    "server.",
1356

1357
    NULL
1358
};
1359

1360
static BlockDriver bdrv_ssh = {
1361
    .format_name                  = "ssh",
1362
    .protocol_name                = "ssh",
1363
    .instance_size                = sizeof(BDRVSSHState),
1364
    .bdrv_parse_filename          = ssh_parse_filename,
1365
    .bdrv_open                    = ssh_open,
1366
    .bdrv_co_create               = ssh_co_create,
1367
    .bdrv_co_create_opts          = ssh_co_create_opts,
1368
    .bdrv_close                   = ssh_close,
1369
    .bdrv_has_zero_init           = ssh_has_zero_init,
1370
    .bdrv_co_readv                = ssh_co_readv,
1371
    .bdrv_co_writev               = ssh_co_writev,
1372
    .bdrv_co_getlength            = ssh_co_getlength,
1373
    .bdrv_co_truncate             = ssh_co_truncate,
1374
    .bdrv_co_flush_to_disk        = ssh_co_flush,
1375
    .bdrv_refresh_filename        = ssh_refresh_filename,
1376
    .bdrv_dirname                 = ssh_bdrv_dirname,
1377
    .create_opts                  = &ssh_create_opts,
1378
    .strong_runtime_opts          = ssh_strong_runtime_opts,
1379
};
1380

1381
static void bdrv_ssh_init(void)
1382
{
1383
    int r;
1384

1385
    r = ssh_init();
1386
    if (r != 0) {
1387
        fprintf(stderr, "libssh initialization failed, %d\n", r);
1388
        exit(EXIT_FAILURE);
1389
    }
1390

1391
#if TRACE_LIBSSH != 0
1392
    ssh_set_log_level(TRACE_LIBSSH);
1393
#endif
1394

1395
    bdrv_register(&bdrv_ssh);
1396
}
1397

1398
block_init(bdrv_ssh_init);
1399