/
ssh.c
1422 lines (1209 loc) · 38.3 KB
/
ssh.c
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
/*
* Secure Shell (ssh) backend for QEMU.
*
* Copyright (C) 2013 Red Hat Inc., Richard W.M. Jones <rjones@redhat.com>
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include "qemu/osdep.h"
#include <libssh/libssh.h>
#include <libssh/sftp.h>
#include "block/block_int.h"
#include "block/qdict.h"
#include "qapi/error.h"
#include "qemu/error-report.h"
#include "qemu/module.h"
#include "qemu/option.h"
#include "qemu/ctype.h"
#include "qemu/cutils.h"
#include "qemu/sockets.h"
#include "qemu/uri.h"
#include "qapi/qapi-visit-sockets.h"
#include "qapi/qapi-visit-block-core.h"
#include "qapi/qmp/qdict.h"
#include "qapi/qmp/qstring.h"
#include "qapi/qobject-input-visitor.h"
#include "qapi/qobject-output-visitor.h"
#include "trace.h"
/*
* TRACE_LIBSSH=<level> enables tracing in libssh itself.
* The meaning of <level> is described here:
* http://api.libssh.org/master/group__libssh__log.html
*/
#define TRACE_LIBSSH 0 /* see: SSH_LOG_* */
typedef struct BDRVSSHState {
/* Coroutine. */
CoMutex lock;
/* SSH connection. */
int sock; /* socket */
ssh_session session; /* ssh session */
sftp_session sftp; /* sftp session */
sftp_file sftp_handle; /* sftp remote file handle */
/*
* File attributes at open. We try to keep the .size field
* updated if it changes (eg by writing at the end of the file).
*/
sftp_attributes attrs;
InetSocketAddress *inet;
/* Used to warn if 'flush' is not supported. */
bool unsafe_flush_warning;
/*
* Store the user name for ssh_refresh_filename() because the
* default depends on the system you are on -- therefore, when we
* generate a filename, it should always contain the user name we
* are actually using.
*/
char *user;
} BDRVSSHState;
static void ssh_state_init(BDRVSSHState *s)
{
memset(s, 0, sizeof *s);
s->sock = -1;
qemu_co_mutex_init(&s->lock);
}
static void ssh_state_free(BDRVSSHState *s)
{
g_free(s->user);
if (s->attrs) {
sftp_attributes_free(s->attrs);
}
if (s->sftp_handle) {
sftp_close(s->sftp_handle);
}
if (s->sftp) {
sftp_free(s->sftp);
}
if (s->session) {
ssh_disconnect(s->session);
ssh_free(s->session); /* This frees s->sock */
}
}
static void GCC_FMT_ATTR(3, 4)
session_error_setg(Error **errp, BDRVSSHState *s, const char *fs, ...)
{
va_list args;
char *msg;
va_start(args, fs);
msg = g_strdup_vprintf(fs, args);
va_end(args);
if (s->session) {
const char *ssh_err;
int ssh_err_code;
/* This is not an errno. See <libssh/libssh.h>. */
ssh_err = ssh_get_error(s->session);
ssh_err_code = ssh_get_error_code(s->session);
error_setg(errp, "%s: %s (libssh error code: %d)",
msg, ssh_err, ssh_err_code);
} else {
error_setg(errp, "%s", msg);
}
g_free(msg);
}
static void GCC_FMT_ATTR(3, 4)
sftp_error_setg(Error **errp, BDRVSSHState *s, const char *fs, ...)
{
va_list args;
char *msg;
va_start(args, fs);
msg = g_strdup_vprintf(fs, args);
va_end(args);
if (s->sftp) {
const char *ssh_err;
int ssh_err_code;
int sftp_err_code;
/* This is not an errno. See <libssh/libssh.h>. */
ssh_err = ssh_get_error(s->session);
ssh_err_code = ssh_get_error_code(s->session);
/* See <libssh/sftp.h>. */
sftp_err_code = sftp_get_error(s->sftp);
error_setg(errp,
"%s: %s (libssh error code: %d, sftp error code: %d)",
msg, ssh_err, ssh_err_code, sftp_err_code);
} else {
error_setg(errp, "%s", msg);
}
g_free(msg);
}
static void sftp_error_trace(BDRVSSHState *s, const char *op)
{
const char *ssh_err;
int ssh_err_code;
int sftp_err_code;
/* This is not an errno. See <libssh/libssh.h>. */
ssh_err = ssh_get_error(s->session);
ssh_err_code = ssh_get_error_code(s->session);
/* See <libssh/sftp.h>. */
sftp_err_code = sftp_get_error(s->sftp);
trace_sftp_error(op, ssh_err, ssh_err_code, sftp_err_code);
}
static int parse_uri(const char *filename, QDict *options, Error **errp)
{
URI *uri = NULL;
QueryParams *qp;
char *port_str;
int i;
uri = uri_parse(filename);
if (!uri) {
return -EINVAL;
}
if (g_strcmp0(uri->scheme, "ssh") != 0) {
error_setg(errp, "URI scheme must be 'ssh'");
goto err;
}
if (!uri->server || strcmp(uri->server, "") == 0) {
error_setg(errp, "missing hostname in URI");
goto err;
}
if (!uri->path || strcmp(uri->path, "") == 0) {
error_setg(errp, "missing remote path in URI");
goto err;
}
qp = query_params_parse(uri->query);
if (!qp) {
error_setg(errp, "could not parse query parameters");
goto err;
}
if(uri->user && strcmp(uri->user, "") != 0) {
qdict_put_str(options, "user", uri->user);
}
qdict_put_str(options, "server.host", uri->server);
port_str = g_strdup_printf("%d", uri->port ?: 22);
qdict_put_str(options, "server.port", port_str);
g_free(port_str);
qdict_put_str(options, "path", uri->path);
/* Pick out any query parameters that we understand, and ignore
* the rest.
*/
for (i = 0; i < qp->n; ++i) {
if (strcmp(qp->p[i].name, "host_key_check") == 0) {
qdict_put_str(options, "host_key_check", qp->p[i].value);
}
}
query_params_free(qp);
uri_free(uri);
return 0;
err:
if (uri) {
uri_free(uri);
}
return -EINVAL;
}
static bool ssh_has_filename_options_conflict(QDict *options, Error **errp)
{
const QDictEntry *qe;
for (qe = qdict_first(options); qe; qe = qdict_next(options, qe)) {
if (!strcmp(qe->key, "host") ||
!strcmp(qe->key, "port") ||
!strcmp(qe->key, "path") ||
!strcmp(qe->key, "user") ||
!strcmp(qe->key, "host_key_check") ||
strstart(qe->key, "server.", NULL))
{
error_setg(errp, "Option '%s' cannot be used with a file name",
qe->key);
return true;
}
}
return false;
}
static void ssh_parse_filename(const char *filename, QDict *options,
Error **errp)
{
if (ssh_has_filename_options_conflict(options, errp)) {
return;
}
parse_uri(filename, options, errp);
}
static int check_host_key_knownhosts(BDRVSSHState *s, Error **errp)
{
int ret;
#ifdef HAVE_LIBSSH_0_8
enum ssh_known_hosts_e state;
int r;
ssh_key pubkey;
enum ssh_keytypes_e pubkey_type;
unsigned char *server_hash = NULL;
size_t server_hash_len;
char *fingerprint = NULL;
state = ssh_session_is_known_server(s->session);
trace_ssh_server_status(state);
switch (state) {
case SSH_KNOWN_HOSTS_OK:
/* OK */
trace_ssh_check_host_key_knownhosts();
break;
case SSH_KNOWN_HOSTS_CHANGED:
ret = -EINVAL;
r = ssh_get_server_publickey(s->session, &pubkey);
if (r == 0) {
r = ssh_get_publickey_hash(pubkey, SSH_PUBLICKEY_HASH_SHA256,
&server_hash, &server_hash_len);
pubkey_type = ssh_key_type(pubkey);
ssh_key_free(pubkey);
}
if (r == 0) {
fingerprint = ssh_get_fingerprint_hash(SSH_PUBLICKEY_HASH_SHA256,
server_hash,
server_hash_len);
ssh_clean_pubkey_hash(&server_hash);
}
if (fingerprint) {
error_setg(errp,
"host key (%s key with fingerprint %s) does not match "
"the one in known_hosts; this may be a possible attack",
ssh_key_type_to_char(pubkey_type), fingerprint);
ssh_string_free_char(fingerprint);
} else {
error_setg(errp,
"host key does not match the one in known_hosts; this "
"may be a possible attack");
}
goto out;
case SSH_KNOWN_HOSTS_OTHER:
ret = -EINVAL;
error_setg(errp,
"host key for this server not found, another type exists");
goto out;
case SSH_KNOWN_HOSTS_UNKNOWN:
ret = -EINVAL;
error_setg(errp, "no host key was found in known_hosts");
goto out;
case SSH_KNOWN_HOSTS_NOT_FOUND:
ret = -ENOENT;
error_setg(errp, "known_hosts file not found");
goto out;
case SSH_KNOWN_HOSTS_ERROR:
ret = -EINVAL;
error_setg(errp, "error while checking the host");
goto out;
default:
ret = -EINVAL;
error_setg(errp, "error while checking for known server (%d)", state);
goto out;
}
#else /* !HAVE_LIBSSH_0_8 */
int state;
state = ssh_is_server_known(s->session);
trace_ssh_server_status(state);
switch (state) {
case SSH_SERVER_KNOWN_OK:
/* OK */
trace_ssh_check_host_key_knownhosts();
break;
case SSH_SERVER_KNOWN_CHANGED:
ret = -EINVAL;
error_setg(errp,
"host key does not match the one in known_hosts; this "
"may be a possible attack");
goto out;
case SSH_SERVER_FOUND_OTHER:
ret = -EINVAL;
error_setg(errp,
"host key for this server not found, another type exists");
goto out;
case SSH_SERVER_FILE_NOT_FOUND:
ret = -ENOENT;
error_setg(errp, "known_hosts file not found");
goto out;
case SSH_SERVER_NOT_KNOWN:
ret = -EINVAL;
error_setg(errp, "no host key was found in known_hosts");
goto out;
case SSH_SERVER_ERROR:
ret = -EINVAL;
error_setg(errp, "server error");
goto out;
default:
ret = -EINVAL;
error_setg(errp, "error while checking for known server (%d)", state);
goto out;
}
#endif /* !HAVE_LIBSSH_0_8 */
/* known_hosts checking successful. */
ret = 0;
out:
return ret;
}
static unsigned hex2decimal(char ch)
{
if (ch >= '0' && ch <= '9') {
return (ch - '0');
} else if (ch >= 'a' && ch <= 'f') {
return 10 + (ch - 'a');
} else if (ch >= 'A' && ch <= 'F') {
return 10 + (ch - 'A');
}
return -1;
}
/* Compare the binary fingerprint (hash of host key) with the
* host_key_check parameter.
*/
static int compare_fingerprint(const unsigned char *fingerprint, size_t len,
const char *host_key_check)
{
unsigned c;
while (len > 0) {
while (*host_key_check == ':')
host_key_check++;
if (!qemu_isxdigit(host_key_check[0]) ||
!qemu_isxdigit(host_key_check[1]))
return 1;
c = hex2decimal(host_key_check[0]) * 16 +
hex2decimal(host_key_check[1]);
if (c - *fingerprint != 0)
return c - *fingerprint;
fingerprint++;
len--;
host_key_check += 2;
}
return *host_key_check - '\0';
}
static int
check_host_key_hash(BDRVSSHState *s, const char *hash,
enum ssh_publickey_hash_type type, Error **errp)
{
int r;
ssh_key pubkey;
unsigned char *server_hash;
size_t server_hash_len;
#ifdef HAVE_LIBSSH_0_8
r = ssh_get_server_publickey(s->session, &pubkey);
#else
r = ssh_get_publickey(s->session, &pubkey);
#endif
if (r != SSH_OK) {
session_error_setg(errp, s, "failed to read remote host key");
return -EINVAL;
}
r = ssh_get_publickey_hash(pubkey, type, &server_hash, &server_hash_len);
ssh_key_free(pubkey);
if (r != 0) {
session_error_setg(errp, s,
"failed reading the hash of the server SSH key");
return -EINVAL;
}
r = compare_fingerprint(server_hash, server_hash_len, hash);
ssh_clean_pubkey_hash(&server_hash);
if (r != 0) {
error_setg(errp, "remote host key does not match host_key_check '%s'",
hash);
return -EPERM;
}
return 0;
}
static int check_host_key(BDRVSSHState *s, SshHostKeyCheck *hkc, Error **errp)
{
SshHostKeyCheckMode mode;
if (hkc) {
mode = hkc->mode;
} else {
mode = SSH_HOST_KEY_CHECK_MODE_KNOWN_HOSTS;
}
switch (mode) {
case SSH_HOST_KEY_CHECK_MODE_NONE:
return 0;
case SSH_HOST_KEY_CHECK_MODE_HASH:
if (hkc->u.hash.type == SSH_HOST_KEY_CHECK_HASH_TYPE_MD5) {
return check_host_key_hash(s, hkc->u.hash.hash,
SSH_PUBLICKEY_HASH_MD5, errp);
} else if (hkc->u.hash.type == SSH_HOST_KEY_CHECK_HASH_TYPE_SHA1) {
return check_host_key_hash(s, hkc->u.hash.hash,
SSH_PUBLICKEY_HASH_SHA1, errp);
}
g_assert_not_reached();
break;
case SSH_HOST_KEY_CHECK_MODE_KNOWN_HOSTS:
return check_host_key_knownhosts(s, errp);
default:
g_assert_not_reached();
}
return -EINVAL;
}
static int authenticate(BDRVSSHState *s, Error **errp)
{
int r, ret;
int method;
/* Try to authenticate with the "none" method. */
r = ssh_userauth_none(s->session, NULL);
if (r == SSH_AUTH_ERROR) {
ret = -EPERM;
session_error_setg(errp, s, "failed to authenticate using none "
"authentication");
goto out;
} else if (r == SSH_AUTH_SUCCESS) {
/* Authenticated! */
ret = 0;
goto out;
}
method = ssh_userauth_list(s->session, NULL);
trace_ssh_auth_methods(method);
/*
* Try to authenticate with publickey, using the ssh-agent
* if available.
*/
if (method & SSH_AUTH_METHOD_PUBLICKEY) {
r = ssh_userauth_publickey_auto(s->session, NULL, NULL);
if (r == SSH_AUTH_ERROR) {
ret = -EINVAL;
session_error_setg(errp, s, "failed to authenticate using "
"publickey authentication");
goto out;
} else if (r == SSH_AUTH_SUCCESS) {
/* Authenticated! */
ret = 0;
goto out;
}
}
ret = -EPERM;
error_setg(errp, "failed to authenticate using publickey authentication "
"and the identities held by your ssh-agent");
out:
return ret;
}
static QemuOptsList ssh_runtime_opts = {
.name = "ssh",
.head = QTAILQ_HEAD_INITIALIZER(ssh_runtime_opts.head),
.desc = {
{
.name = "host",
.type = QEMU_OPT_STRING,
.help = "Host to connect to",
},
{
.name = "port",
.type = QEMU_OPT_NUMBER,
.help = "Port to connect to",
},
{
.name = "host_key_check",
.type = QEMU_OPT_STRING,
.help = "Defines how and what to check the host key against",
},
{ /* end of list */ }
},
};
static bool ssh_process_legacy_options(QDict *output_opts,
QemuOpts *legacy_opts,
Error **errp)
{
const char *host = qemu_opt_get(legacy_opts, "host");
const char *port = qemu_opt_get(legacy_opts, "port");
const char *host_key_check = qemu_opt_get(legacy_opts, "host_key_check");
if (!host && port) {
error_setg(errp, "port may not be used without host");
return false;
}
if (host) {
qdict_put_str(output_opts, "server.host", host);
qdict_put_str(output_opts, "server.port", port ?: stringify(22));
}
if (host_key_check) {
if (strcmp(host_key_check, "no") == 0) {
qdict_put_str(output_opts, "host-key-check.mode", "none");
} else if (strncmp(host_key_check, "md5:", 4) == 0) {
qdict_put_str(output_opts, "host-key-check.mode", "hash");
qdict_put_str(output_opts, "host-key-check.type", "md5");
qdict_put_str(output_opts, "host-key-check.hash",
&host_key_check[4]);
} else if (strncmp(host_key_check, "sha1:", 5) == 0) {
qdict_put_str(output_opts, "host-key-check.mode", "hash");
qdict_put_str(output_opts, "host-key-check.type", "sha1");
qdict_put_str(output_opts, "host-key-check.hash",
&host_key_check[5]);
} else if (strcmp(host_key_check, "yes") == 0) {
qdict_put_str(output_opts, "host-key-check.mode", "known_hosts");
} else {
error_setg(errp, "unknown host_key_check setting (%s)",
host_key_check);
return false;
}
}
return true;
}
static BlockdevOptionsSsh *ssh_parse_options(QDict *options, Error **errp)
{
BlockdevOptionsSsh *result = NULL;
QemuOpts *opts = NULL;
Error *local_err = NULL;
const QDictEntry *e;
Visitor *v;
/* Translate legacy options */
opts = qemu_opts_create(&ssh_runtime_opts, NULL, 0, &error_abort);
qemu_opts_absorb_qdict(opts, options, &local_err);
if (local_err) {
error_propagate(errp, local_err);
goto fail;
}
if (!ssh_process_legacy_options(options, opts, errp)) {
goto fail;
}
/* Create the QAPI object */
v = qobject_input_visitor_new_flat_confused(options, errp);
if (!v) {
goto fail;
}
visit_type_BlockdevOptionsSsh(v, NULL, &result, &local_err);
visit_free(v);
if (local_err) {
error_propagate(errp, local_err);
goto fail;
}
/* Remove the processed options from the QDict (the visitor processes
* _all_ options in the QDict) */
while ((e = qdict_first(options))) {
qdict_del(options, e->key);
}
fail:
qemu_opts_del(opts);
return result;
}
static int connect_to_ssh(BDRVSSHState *s, BlockdevOptionsSsh *opts,
int ssh_flags, int creat_mode, Error **errp)
{
int r, ret;
unsigned int port = 0;
int new_sock = -1;
if (opts->has_user) {
s->user = g_strdup(opts->user);
} else {
s->user = g_strdup(g_get_user_name());
if (!s->user) {
error_setg_errno(errp, errno, "Can't get user name");
ret = -errno;
goto err;
}
}
/* Pop the config into our state object, Exit if invalid */
s->inet = opts->server;
opts->server = NULL;
if (qemu_strtoui(s->inet->port, NULL, 10, &port) < 0) {
error_setg(errp, "Use only numeric port value");
ret = -EINVAL;
goto err;
}
/* Open the socket and connect. */
new_sock = inet_connect_saddr(s->inet, errp);
if (new_sock < 0) {
ret = -EIO;
goto err;
}
/*
* Try to disable the Nagle algorithm on TCP sockets to reduce latency,
* but do not fail if it cannot be disabled.
*/
r = socket_set_nodelay(new_sock);
if (r < 0) {
warn_report("can't set TCP_NODELAY for the ssh server %s: %s",
s->inet->host, strerror(errno));
}
/* Create SSH session. */
s->session = ssh_new();
if (!s->session) {
ret = -EINVAL;
session_error_setg(errp, s, "failed to initialize libssh session");
goto err;
}
/*
* Make sure we are in blocking mode during the connection and
* authentication phases.
*/
ssh_set_blocking(s->session, 1);
r = ssh_options_set(s->session, SSH_OPTIONS_USER, s->user);
if (r < 0) {
ret = -EINVAL;
session_error_setg(errp, s,
"failed to set the user in the libssh session");
goto err;
}
r = ssh_options_set(s->session, SSH_OPTIONS_HOST, s->inet->host);
if (r < 0) {
ret = -EINVAL;
session_error_setg(errp, s,
"failed to set the host in the libssh session");
goto err;
}
if (port > 0) {
r = ssh_options_set(s->session, SSH_OPTIONS_PORT, &port);
if (r < 0) {
ret = -EINVAL;
session_error_setg(errp, s,
"failed to set the port in the libssh session");
goto err;
}
}
r = ssh_options_set(s->session, SSH_OPTIONS_COMPRESSION, "none");
if (r < 0) {
ret = -EINVAL;
session_error_setg(errp, s,
"failed to disable the compression in the libssh "
"session");
goto err;
}
/* Read ~/.ssh/config. */
r = ssh_options_parse_config(s->session, NULL);
if (r < 0) {
ret = -EINVAL;
session_error_setg(errp, s, "failed to parse ~/.ssh/config");
goto err;
}
r = ssh_options_set(s->session, SSH_OPTIONS_FD, &new_sock);
if (r < 0) {
ret = -EINVAL;
session_error_setg(errp, s,
"failed to set the socket in the libssh session");
goto err;
}
/* libssh took ownership of the socket. */
s->sock = new_sock;
new_sock = -1;
/* Connect. */
r = ssh_connect(s->session);
if (r != SSH_OK) {
ret = -EINVAL;
session_error_setg(errp, s, "failed to establish SSH session");
goto err;
}
/* Check the remote host's key against known_hosts. */
ret = check_host_key(s, opts->host_key_check, errp);
if (ret < 0) {
goto err;
}
/* Authenticate. */
ret = authenticate(s, errp);
if (ret < 0) {
goto err;
}
/* Start SFTP. */
s->sftp = sftp_new(s->session);
if (!s->sftp) {
session_error_setg(errp, s, "failed to create sftp handle");
ret = -EINVAL;
goto err;
}
r = sftp_init(s->sftp);
if (r < 0) {
sftp_error_setg(errp, s, "failed to initialize sftp handle");
ret = -EINVAL;
goto err;
}
/* Open the remote file. */
trace_ssh_connect_to_ssh(opts->path, ssh_flags, creat_mode);
s->sftp_handle = sftp_open(s->sftp, opts->path, ssh_flags, creat_mode);
if (!s->sftp_handle) {
sftp_error_setg(errp, s, "failed to open remote file '%s'",
opts->path);
ret = -EINVAL;
goto err;
}
/* Make sure the SFTP file is handled in blocking mode. */
sftp_file_set_blocking(s->sftp_handle);
s->attrs = sftp_fstat(s->sftp_handle);
if (!s->attrs) {
sftp_error_setg(errp, s, "failed to read file attributes");
return -EINVAL;
}
return 0;
err:
if (s->attrs) {
sftp_attributes_free(s->attrs);
}
s->attrs = NULL;
if (s->sftp_handle) {
sftp_close(s->sftp_handle);
}
s->sftp_handle = NULL;
if (s->sftp) {
sftp_free(s->sftp);
}
s->sftp = NULL;
if (s->session) {
ssh_disconnect(s->session);
ssh_free(s->session);
}
s->session = NULL;
s->sock = -1;
if (new_sock >= 0) {
close(new_sock);
}
return ret;
}
static int ssh_file_open(BlockDriverState *bs, QDict *options, int bdrv_flags,
Error **errp)
{
BDRVSSHState *s = bs->opaque;
BlockdevOptionsSsh *opts;
int ret;
int ssh_flags;
ssh_state_init(s);
ssh_flags = 0;
if (bdrv_flags & BDRV_O_RDWR) {
ssh_flags |= O_RDWR;
} else {
ssh_flags |= O_RDONLY;
}
opts = ssh_parse_options(options, errp);
if (opts == NULL) {
return -EINVAL;
}
/* Start up SSH. */
ret = connect_to_ssh(s, opts, ssh_flags, 0, errp);
if (ret < 0) {
goto err;
}
/* Go non-blocking. */
ssh_set_blocking(s->session, 0);
qapi_free_BlockdevOptionsSsh(opts);
return 0;
err:
qapi_free_BlockdevOptionsSsh(opts);
return ret;
}
/* Note: This is a blocking operation */
static int ssh_grow_file(BDRVSSHState *s, int64_t offset, Error **errp)
{
ssize_t ret;
char c[1] = { '\0' };
int was_blocking = ssh_is_blocking(s->session);
/* offset must be strictly greater than the current size so we do
* not overwrite anything */
assert(offset > 0 && offset > s->attrs->size);
ssh_set_blocking(s->session, 1);
sftp_seek64(s->sftp_handle, offset - 1);
ret = sftp_write(s->sftp_handle, c, 1);
ssh_set_blocking(s->session, was_blocking);
if (ret < 0) {
sftp_error_setg(errp, s, "Failed to grow file");
return -EIO;
}
s->attrs->size = offset;
return 0;
}
static QemuOptsList ssh_create_opts = {
.name = "ssh-create-opts",
.head = QTAILQ_HEAD_INITIALIZER(ssh_create_opts.head),
.desc = {
{
.name = BLOCK_OPT_SIZE,
.type = QEMU_OPT_SIZE,
.help = "Virtual disk size"
},
{ /* end of list */ }
}
};
static int ssh_co_create(BlockdevCreateOptions *options, Error **errp)
{
BlockdevCreateOptionsSsh *opts = &options->u.ssh;
BDRVSSHState s;
int ret;
assert(options->driver == BLOCKDEV_DRIVER_SSH);
ssh_state_init(&s);
ret = connect_to_ssh(&s, opts->location,
O_RDWR | O_CREAT | O_TRUNC,
0644, errp);
if (ret < 0) {
goto fail;
}
if (opts->size > 0) {
ret = ssh_grow_file(&s, opts->size, errp);
if (ret < 0) {
goto fail;
}
}
ret = 0;
fail:
ssh_state_free(&s);
return ret;
}
static int coroutine_fn ssh_co_create_opts(const char *filename, QemuOpts *opts,
Error **errp)
{
BlockdevCreateOptions *create_options;
BlockdevCreateOptionsSsh *ssh_opts;
int ret;
QDict *uri_options = NULL;
create_options = g_new0(BlockdevCreateOptions, 1);
create_options->driver = BLOCKDEV_DRIVER_SSH;
ssh_opts = &create_options->u.ssh;
/* Get desired file size. */
ssh_opts->size = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0),
BDRV_SECTOR_SIZE);
trace_ssh_co_create_opts(ssh_opts->size);
uri_options = qdict_new();
ret = parse_uri(filename, uri_options, errp);
if (ret < 0) {
goto out;
}
ssh_opts->location = ssh_parse_options(uri_options, errp);
if (ssh_opts->location == NULL) {
ret = -EINVAL;
goto out;
}
ret = ssh_co_create(create_options, errp);
out:
qobject_unref(uri_options);
qapi_free_BlockdevCreateOptions(create_options);
return ret;