forked from ParallelSSH/ssh-python
-
Notifications
You must be signed in to change notification settings - Fork 1
Expand file tree
/
Copy pathlibgcrypt.c
More file actions
1063 lines (953 loc) · 30.3 KB
/
libgcrypt.c
File metadata and controls
1063 lines (953 loc) · 30.3 KB
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
/*
* This file is part of the SSH Library
*
* Copyright (c) 2009 by Aris Adamantiadis
* Copyright (C) 2016 g10 Code GmbH
*
* The SSH Library is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation; either version 2.1 of the License, or (at your
* option) any later version.
*
* The SSH Library is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
* License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with the SSH Library; see the file COPYING. If not, write to
* the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
* MA 02111-1307, USA.
*/
#include "config.h"
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <stdbool.h>
#include "libssh/priv.h"
#include "libssh/session.h"
#include "libssh/crypto.h"
#include "libssh/wrapper.h"
#include "libssh/string.h"
#include "libssh/misc.h"
#ifdef HAVE_GCRYPT_CHACHA_POLY
#include "libssh/chacha20-poly1305-common.h"
#endif
#ifdef HAVE_LIBGCRYPT
#include <gcrypt.h>
#ifdef HAVE_GCRYPT_CHACHA_POLY
struct chacha20_poly1305_keysched {
bool initialized;
/* cipher handle used for encrypting the packets */
gcry_cipher_hd_t main_hd;
/* cipher handle used for encrypting the length field */
gcry_cipher_hd_t header_hd;
/* mac handle used for authenticating the packets */
gcry_mac_hd_t mac_hd;
};
static const uint8_t zero_block[CHACHA20_BLOCKSIZE] = {0};
#endif /* HAVE_GCRYPT_CHACHA_POLY */
static int libgcrypt_initialized = 0;
static int alloc_key(struct ssh_cipher_struct *cipher) {
cipher->key = malloc(cipher->keylen);
if (cipher->key == NULL) {
return -1;
}
return 0;
}
void ssh_reseed(void){
}
#ifdef HAVE_GCRYPT_ECC
static int nid_to_md_algo(int nid)
{
switch (nid) {
case NID_gcrypt_nistp256:
return GCRY_MD_SHA256;
case NID_gcrypt_nistp384:
return GCRY_MD_SHA384;
case NID_gcrypt_nistp521:
return GCRY_MD_SHA512;
}
return GCRY_MD_NONE;
}
void evp(int nid, unsigned char *digest, size_t len,
unsigned char *hash, unsigned int *hlen)
{
int algo = nid_to_md_algo(nid);
/* Note: What gcrypt calls 'hash' is called 'digest' here and
vice-versa. */
gcry_md_hash_buffer(algo, hash, digest, len);
*hlen = gcry_md_get_algo_dlen(algo);
}
EVPCTX evp_init(int nid)
{
gcry_error_t err;
int algo = nid_to_md_algo(nid);
EVPCTX ctx;
err = gcry_md_open(&ctx, algo, 0);
if (err) {
return NULL;
}
return ctx;
}
void evp_update(EVPCTX ctx, const void *data, size_t len)
{
gcry_md_write(ctx, data, len);
}
void evp_final(EVPCTX ctx, unsigned char *md, unsigned int *mdlen)
{
int algo = gcry_md_get_algo(ctx);
*mdlen = gcry_md_get_algo_dlen(algo);
memcpy(md, gcry_md_read(ctx, algo), *mdlen);
gcry_md_close(ctx);
}
#endif
int ssh_kdf(struct ssh_crypto_struct *crypto,
unsigned char *key, size_t key_len,
uint8_t key_type, unsigned char *output,
size_t requested_len)
{
return sshkdf_derive_key(crypto, key, key_len,
key_type, output, requested_len);
}
HMACCTX hmac_init(const void *key, size_t len, enum ssh_hmac_e type) {
HMACCTX c = NULL;
switch(type) {
case SSH_HMAC_SHA1:
gcry_md_open(&c, GCRY_MD_SHA1, GCRY_MD_FLAG_HMAC);
break;
case SSH_HMAC_SHA256:
gcry_md_open(&c, GCRY_MD_SHA256, GCRY_MD_FLAG_HMAC);
break;
case SSH_HMAC_SHA512:
gcry_md_open(&c, GCRY_MD_SHA512, GCRY_MD_FLAG_HMAC);
break;
case SSH_HMAC_MD5:
gcry_md_open(&c, GCRY_MD_MD5, GCRY_MD_FLAG_HMAC);
break;
default:
c = NULL;
}
gcry_md_setkey(c, key, len);
return c;
}
int hmac_update(HMACCTX c, const void *data, size_t len) {
gcry_md_write(c, data, len);
return 1;
}
int hmac_final(HMACCTX c, unsigned char *hashmacbuf, size_t *len) {
unsigned int tmp = gcry_md_get_algo_dlen(gcry_md_get_algo(c));
*len = (size_t)tmp;
memcpy(hashmacbuf, gcry_md_read(c, 0), *len);
gcry_md_close(c);
return 1;
}
#ifdef WITH_BLOWFISH_CIPHER
/* the wrapper functions for blowfish */
static int blowfish_set_key(struct ssh_cipher_struct *cipher, void *key, void *IV){
if (cipher->key == NULL) {
if (alloc_key(cipher) < 0) {
return -1;
}
if (gcry_cipher_open(&cipher->key[0], GCRY_CIPHER_BLOWFISH,
GCRY_CIPHER_MODE_CBC, 0)) {
SAFE_FREE(cipher->key);
return -1;
}
if (gcry_cipher_setkey(cipher->key[0], key, 16)) {
gcry_cipher_close(cipher->key[0]);
SAFE_FREE(cipher->key);
return -1;
}
if (gcry_cipher_setiv(cipher->key[0], IV, 8)) {
gcry_cipher_close(cipher->key[0]);
SAFE_FREE(cipher->key);
return -1;
}
}
return 0;
}
static void blowfish_encrypt(struct ssh_cipher_struct *cipher, void *in,
void *out, unsigned long len) {
gcry_cipher_encrypt(cipher->key[0], out, len, in, len);
}
static void blowfish_decrypt(struct ssh_cipher_struct *cipher, void *in,
void *out, unsigned long len) {
gcry_cipher_decrypt(cipher->key[0], out, len, in, len);
}
#endif /* WITH_BLOWFISH_CIPHER */
static int aes_set_key(struct ssh_cipher_struct *cipher, void *key, void *IV) {
int mode=GCRY_CIPHER_MODE_CBC;
if (cipher->key == NULL) {
if (alloc_key(cipher) < 0) {
return -1;
}
if(strstr(cipher->name,"-ctr"))
mode=GCRY_CIPHER_MODE_CTR;
if (strstr(cipher->name, "-gcm"))
mode = GCRY_CIPHER_MODE_GCM;
switch (cipher->keysize) {
case 128:
if (gcry_cipher_open(&cipher->key[0], GCRY_CIPHER_AES128,
mode, 0)) {
SAFE_FREE(cipher->key);
return -1;
}
break;
case 192:
if (gcry_cipher_open(&cipher->key[0], GCRY_CIPHER_AES192,
mode, 0)) {
SAFE_FREE(cipher->key);
return -1;
}
break;
case 256:
if (gcry_cipher_open(&cipher->key[0], GCRY_CIPHER_AES256,
mode, 0)) {
SAFE_FREE(cipher->key);
return -1;
}
break;
default:
SSH_LOG(SSH_LOG_WARNING, "Unksupported key length %u.", cipher->keysize);
SAFE_FREE(cipher->key);
return -1;
}
if (gcry_cipher_setkey(cipher->key[0], key, cipher->keysize / 8)) {
gcry_cipher_close(cipher->key[0]);
SAFE_FREE(cipher->key);
return -1;
}
if(mode == GCRY_CIPHER_MODE_CBC){
if (gcry_cipher_setiv(cipher->key[0], IV, 16)) {
gcry_cipher_close(cipher->key[0]);
SAFE_FREE(cipher->key);
return -1;
}
} else if (mode == GCRY_CIPHER_MODE_GCM) {
/* Store the IV so we can handle the packet counter increments later
* The IV is passed to the cipher context later.
*/
memcpy(cipher->last_iv, IV, AES_GCM_IVLEN);
} else {
if(gcry_cipher_setctr(cipher->key[0],IV,16)){
gcry_cipher_close(cipher->key[0]);
SAFE_FREE(cipher->key);
return -1;
}
}
}
return 0;
}
static void aes_encrypt(struct ssh_cipher_struct *cipher,
void *in,
void *out,
size_t len)
{
gcry_cipher_encrypt(cipher->key[0], out, len, in, len);
}
static void aes_decrypt(struct ssh_cipher_struct *cipher,
void *in,
void *out,
size_t len)
{
gcry_cipher_decrypt(cipher->key[0], out, len, in, len);
}
static int
aes_aead_get_length(struct ssh_cipher_struct *cipher,
void *in,
uint8_t *out,
size_t len,
uint64_t seq)
{
(void)cipher;
(void)seq;
/* The length is not encrypted: Copy it to the result buffer */
memcpy(out, in, len);
return SSH_OK;
}
static void
aes_gcm_encrypt(struct ssh_cipher_struct *cipher,
void *in,
void *out,
size_t len,
uint8_t *tag,
uint64_t seq)
{
gpg_error_t err;
size_t aadlen, authlen;
(void)seq;
aadlen = cipher->lenfield_blocksize;
authlen = cipher->tag_size;
/* increment IV */
err = gcry_cipher_setiv(cipher->key[0],
cipher->last_iv,
AES_GCM_IVLEN);
/* This actually does not increment the packet counter for the
* current encryption operation, but for the next one. The first
* operation needs to be completed with the derived IV.
*
* The IV buffer has the following structure:
* [ 4B static IV ][ 8B packet counter ][ 4B block counter ]
*/
uint64_inc(cipher->last_iv + 4);
if (err) {
SSH_LOG(SSH_LOG_WARNING, "gcry_cipher_setiv failed: %s",
gpg_strerror(err));
return;
}
/* Pass the authenticated data (packet_length) */
err = gcry_cipher_authenticate(cipher->key[0], in, aadlen);
if (err) {
SSH_LOG(SSH_LOG_WARNING, "gcry_cipher_authenticate failed: %s",
gpg_strerror(err));
return;
}
memcpy(out, in, aadlen);
/* Encrypt the rest of the data */
err = gcry_cipher_encrypt(cipher->key[0],
(unsigned char *)out + aadlen,
len - aadlen,
(unsigned char *)in + aadlen,
len - aadlen);
if (err) {
SSH_LOG(SSH_LOG_WARNING, "gcry_cipher_encrypt failed: %s",
gpg_strerror(err));
return;
}
/* Calculate the tag */
err = gcry_cipher_gettag(cipher->key[0],
(void *)tag,
authlen);
if (err) {
SSH_LOG(SSH_LOG_WARNING, "gcry_cipher_gettag failed: %s",
gpg_strerror(err));
return;
}
}
static int
aes_gcm_decrypt(struct ssh_cipher_struct *cipher,
void *complete_packet,
uint8_t *out,
size_t encrypted_size,
uint64_t seq)
{
gpg_error_t err;
size_t aadlen, authlen;
(void)seq;
aadlen = cipher->lenfield_blocksize;
authlen = cipher->tag_size;
/* increment IV */
err = gcry_cipher_setiv(cipher->key[0],
cipher->last_iv,
AES_GCM_IVLEN);
/* This actually does not increment the packet counter for the
* current encryption operation, but for the next one. The first
* operation needs to be completed with the derived IV.
*
* The IV buffer has the following structure:
* [ 4B static IV ][ 8B packet counter ][ 4B block counter ]
*/
uint64_inc(cipher->last_iv + 4);
if (err) {
SSH_LOG(SSH_LOG_WARNING, "gcry_cipher_setiv failed: %s",
gpg_strerror(err));
return SSH_ERROR;
}
/* Pass the authenticated data (packet_length) */
err = gcry_cipher_authenticate(cipher->key[0],
complete_packet,
aadlen);
if (err) {
SSH_LOG(SSH_LOG_WARNING, "gcry_cipher_authenticate failed: %s",
gpg_strerror(err));
return SSH_ERROR;
}
/* Do not copy the length to the target buffer, because it is already processed */
//memcpy(out, complete_packet, aadlen);
/* Encrypt the rest of the data */
err = gcry_cipher_decrypt(cipher->key[0],
out,
encrypted_size,
(unsigned char *)complete_packet + aadlen,
encrypted_size);
if (err) {
SSH_LOG(SSH_LOG_WARNING, "gcry_cipher_decrypt failed: %s",
gpg_strerror(err));
return SSH_ERROR;
}
/* Check the tag */
err = gcry_cipher_checktag(cipher->key[0],
(unsigned char *)complete_packet + aadlen + encrypted_size,
authlen);
if (gpg_err_code(err) == GPG_ERR_CHECKSUM) {
SSH_LOG(SSH_LOG_WARNING, "The authentication tag does not match");
return SSH_ERROR;
} else if (err != GPG_ERR_NO_ERROR) {
SSH_LOG(SSH_LOG_WARNING, "General error while decryption: %s",
gpg_strerror(err));
return SSH_ERROR;
}
return SSH_OK;
}
static int des3_set_key(struct ssh_cipher_struct *cipher, void *key, void *IV) {
if (cipher->key == NULL) {
if (alloc_key(cipher) < 0) {
return -1;
}
if (gcry_cipher_open(&cipher->key[0], GCRY_CIPHER_3DES,
GCRY_CIPHER_MODE_CBC, 0)) {
SAFE_FREE(cipher->key);
return -1;
}
if (gcry_cipher_setkey(cipher->key[0], key, 24)) {
gcry_cipher_close(cipher->key[0]);
SAFE_FREE(cipher->key);
return -1;
}
if (gcry_cipher_setiv(cipher->key[0], IV, 8)) {
gcry_cipher_close(cipher->key[0]);
SAFE_FREE(cipher->key);
return -1;
}
}
return 0;
}
static void des3_encrypt(struct ssh_cipher_struct *cipher, void *in,
void *out, unsigned long len) {
gcry_cipher_encrypt(cipher->key[0], out, len, in, len);
}
static void des3_decrypt(struct ssh_cipher_struct *cipher, void *in,
void *out, unsigned long len) {
gcry_cipher_decrypt(cipher->key[0], out, len, in, len);
}
#ifdef HAVE_GCRYPT_CHACHA_POLY
static void chacha20_cleanup(struct ssh_cipher_struct *cipher)
{
struct chacha20_poly1305_keysched *ctx = NULL;
if (cipher->chacha20_schedule == NULL) {
return;
}
ctx = cipher->chacha20_schedule;
if (ctx->initialized) {
gcry_cipher_close(ctx->main_hd);
gcry_cipher_close(ctx->header_hd);
gcry_mac_close(ctx->mac_hd);
ctx->initialized = false;
}
SAFE_FREE(cipher->chacha20_schedule);
}
static int chacha20_set_encrypt_key(struct ssh_cipher_struct *cipher,
void *key,
UNUSED_PARAM(void *IV))
{
struct chacha20_poly1305_keysched *ctx = NULL;
uint8_t *u8key = key;
gpg_error_t err;
if (cipher->chacha20_schedule == NULL) {
ctx = calloc(1, sizeof(*ctx));
if (ctx == NULL) {
return -1;
}
cipher->chacha20_schedule = ctx;
} else {
ctx = cipher->chacha20_schedule;
}
if (!ctx->initialized) {
/* Open cipher/mac handles. */
err = gcry_cipher_open(&ctx->main_hd, GCRY_CIPHER_CHACHA20,
GCRY_CIPHER_MODE_STREAM, 0);
if (err != 0) {
SSH_LOG(SSH_LOG_WARNING, "gcry_cipher_open failed: %s",
gpg_strerror(err));
SAFE_FREE(cipher->chacha20_schedule);
return -1;
}
err = gcry_cipher_open(&ctx->header_hd, GCRY_CIPHER_CHACHA20,
GCRY_CIPHER_MODE_STREAM, 0);
if (err != 0) {
SSH_LOG(SSH_LOG_WARNING, "gcry_cipher_open failed: %s",
gpg_strerror(err));
gcry_cipher_close(ctx->main_hd);
SAFE_FREE(cipher->chacha20_schedule);
return -1;
}
err = gcry_mac_open(&ctx->mac_hd, GCRY_MAC_POLY1305, 0, NULL);
if (err != 0) {
SSH_LOG(SSH_LOG_WARNING, "gcry_mac_open failed: %s",
gpg_strerror(err));
gcry_cipher_close(ctx->main_hd);
gcry_cipher_close(ctx->header_hd);
SAFE_FREE(cipher->chacha20_schedule);
return -1;
}
ctx->initialized = true;
}
err = gcry_cipher_setkey(ctx->main_hd, u8key, CHACHA20_KEYLEN);
if (err != 0) {
SSH_LOG(SSH_LOG_WARNING, "gcry_cipher_setkey failed: %s",
gpg_strerror(err));
chacha20_cleanup(cipher);
return -1;
}
err = gcry_cipher_setkey(ctx->header_hd, u8key + CHACHA20_KEYLEN,
CHACHA20_KEYLEN);
if (err != 0) {
SSH_LOG(SSH_LOG_WARNING, "gcry_cipher_setkey failed: %s",
gpg_strerror(err));
chacha20_cleanup(cipher);
return -1;
}
return 0;
}
static void chacha20_poly1305_aead_encrypt(struct ssh_cipher_struct *cipher,
void *in,
void *out,
size_t len,
uint8_t *tag,
uint64_t seq)
{
struct ssh_packet_header *in_packet = in, *out_packet = out;
struct chacha20_poly1305_keysched *ctx = cipher->chacha20_schedule;
uint8_t poly_key[CHACHA20_BLOCKSIZE];
size_t taglen = POLY1305_TAGLEN;
gpg_error_t err;
seq = htonll(seq);
/* step 1, prepare the poly1305 key */
err = gcry_cipher_setiv(ctx->main_hd, (uint8_t *)&seq, sizeof(seq));
if (err != 0) {
SSH_LOG(SSH_LOG_WARNING, "gcry_cipher_setiv failed: %s",
gpg_strerror(err));
goto out;
}
/* Output full ChaCha block so that counter increases by one for
* payload encryption step. */
err = gcry_cipher_encrypt(ctx->main_hd,
poly_key,
sizeof(poly_key),
zero_block,
sizeof(zero_block));
if (err != 0) {
SSH_LOG(SSH_LOG_WARNING, "gcry_cipher_encrypt failed: %s",
gpg_strerror(err));
goto out;
}
err = gcry_mac_setkey(ctx->mac_hd, poly_key, POLY1305_KEYLEN);
if (err != 0) {
SSH_LOG(SSH_LOG_WARNING, "gcry_mac_setkey failed: %s",
gpg_strerror(err));
goto out;
}
/* step 2, encrypt length field */
err = gcry_cipher_setiv(ctx->header_hd, (uint8_t *)&seq, sizeof(seq));
if (err != 0) {
SSH_LOG(SSH_LOG_WARNING, "gcry_cipher_setiv failed: %s",
gpg_strerror(err));
goto out;
}
err = gcry_cipher_encrypt(ctx->header_hd,
(uint8_t *)&out_packet->length,
sizeof(uint32_t),
(uint8_t *)&in_packet->length,
sizeof(uint32_t));
if (err != 0) {
SSH_LOG(SSH_LOG_WARNING, "gcry_cipher_encrypt failed: %s",
gpg_strerror(err));
goto out;
}
/* step 3, encrypt packet payload (main_hd counter == 1) */
err = gcry_cipher_encrypt(ctx->main_hd,
out_packet->payload,
len - sizeof(uint32_t),
in_packet->payload,
len - sizeof(uint32_t));
if (err != 0) {
SSH_LOG(SSH_LOG_WARNING, "gcry_cipher_encrypt failed: %s",
gpg_strerror(err));
goto out;
}
/* step 4, compute the MAC */
err = gcry_mac_write(ctx->mac_hd, (uint8_t *)out_packet, len);
if (err != 0) {
SSH_LOG(SSH_LOG_WARNING, "gcry_mac_write failed: %s",
gpg_strerror(err));
goto out;
}
err = gcry_mac_read(ctx->mac_hd, tag, &taglen);
if (err != 0) {
SSH_LOG(SSH_LOG_WARNING, "gcry_mac_read failed: %s",
gpg_strerror(err));
goto out;
}
out:
explicit_bzero(poly_key, sizeof(poly_key));
}
static int chacha20_poly1305_aead_decrypt_length(
struct ssh_cipher_struct *cipher,
void *in,
uint8_t *out,
size_t len,
uint64_t seq)
{
struct chacha20_poly1305_keysched *ctx = cipher->chacha20_schedule;
gpg_error_t err;
if (len < sizeof(uint32_t)) {
return SSH_ERROR;
}
seq = htonll(seq);
err = gcry_cipher_setiv(ctx->header_hd, (uint8_t *)&seq, sizeof(seq));
if (err != 0) {
SSH_LOG(SSH_LOG_WARNING, "gcry_cipher_setiv failed: %s",
gpg_strerror(err));
return SSH_ERROR;
}
err = gcry_cipher_decrypt(ctx->header_hd,
out,
sizeof(uint32_t),
in,
sizeof(uint32_t));
if (err != 0) {
SSH_LOG(SSH_LOG_WARNING, "gcry_cipher_decrypt failed: %s",
gpg_strerror(err));
return SSH_ERROR;
}
return SSH_OK;
}
static int chacha20_poly1305_aead_decrypt(struct ssh_cipher_struct *cipher,
void *complete_packet,
uint8_t *out,
size_t encrypted_size,
uint64_t seq)
{
struct chacha20_poly1305_keysched *ctx = cipher->chacha20_schedule;
uint8_t *mac = (uint8_t *)complete_packet + sizeof(uint32_t) +
encrypted_size;
uint8_t poly_key[CHACHA20_BLOCKSIZE];
int ret = SSH_ERROR;
gpg_error_t err;
seq = htonll(seq);
/* step 1, prepare the poly1305 key */
err = gcry_cipher_setiv(ctx->main_hd, (uint8_t *)&seq, sizeof(seq));
if (err != 0) {
SSH_LOG(SSH_LOG_WARNING, "gcry_cipher_setiv failed: %s",
gpg_strerror(err));
goto out;
}
/* Output full ChaCha block so that counter increases by one for
* decryption step. */
err = gcry_cipher_encrypt(ctx->main_hd,
poly_key,
sizeof(poly_key),
zero_block,
sizeof(zero_block));
if (err != 0) {
SSH_LOG(SSH_LOG_WARNING, "gcry_cipher_encrypt failed: %s",
gpg_strerror(err));
goto out;
}
err = gcry_mac_setkey(ctx->mac_hd, poly_key, POLY1305_KEYLEN);
if (err != 0) {
SSH_LOG(SSH_LOG_WARNING, "gcry_mac_setkey failed: %s",
gpg_strerror(err));
goto out;
}
/* step 2, check MAC */
err = gcry_mac_write(ctx->mac_hd, (uint8_t *)complete_packet,
encrypted_size + sizeof(uint32_t));
if (err != 0) {
SSH_LOG(SSH_LOG_WARNING, "gcry_mac_write failed: %s",
gpg_strerror(err));
goto out;
}
err = gcry_mac_verify(ctx->mac_hd, mac, POLY1305_TAGLEN);
if (gpg_err_code(err) == GPG_ERR_CHECKSUM) {
SSH_LOG(SSH_LOG_PACKET, "poly1305 verify error");
goto out;
} else if (err != 0) {
SSH_LOG(SSH_LOG_WARNING, "gcry_mac_verify failed: %s",
gpg_strerror(err));
goto out;
}
/* step 3, decrypt packet payload (main_hd counter == 1) */
err = gcry_cipher_decrypt(ctx->main_hd,
out,
encrypted_size,
(uint8_t *)complete_packet + sizeof(uint32_t),
encrypted_size);
if (err != 0) {
SSH_LOG(SSH_LOG_WARNING, "gcry_cipher_decrypt failed: %s",
gpg_strerror(err));
goto out;
}
ret = SSH_OK;
out:
explicit_bzero(poly_key, sizeof(poly_key));
return ret;
}
#endif /* HAVE_GCRYPT_CHACHA_POLY */
#ifdef WITH_INSECURE_NONE
static void
none_crypt(UNUSED_PARAM(struct ssh_cipher_struct *cipher),
void *in,
void *out,
size_t len)
{
memcpy(out, in, len);
}
#endif /* WITH_INSECURE_NONE */
/* the table of supported ciphers */
static struct ssh_cipher_struct ssh_ciphertab[] = {
#ifdef WITH_BLOWFISH_CIPHER
{
.name = "blowfish-cbc",
.blocksize = 8,
.keylen = sizeof(gcry_cipher_hd_t),
.key = NULL,
.keysize = 128,
.set_encrypt_key = blowfish_set_key,
.set_decrypt_key = blowfish_set_key,
.encrypt = blowfish_encrypt,
.decrypt = blowfish_decrypt
},
#endif /* WITH_BLOWFISH_CIPHER */
{
.name = "aes128-ctr",
.blocksize = 16,
.keylen = sizeof(gcry_cipher_hd_t),
.key = NULL,
.keysize = 128,
.set_encrypt_key = aes_set_key,
.set_decrypt_key = aes_set_key,
.encrypt = aes_encrypt,
.decrypt = aes_encrypt
},
{
.name = "aes192-ctr",
.blocksize = 16,
.keylen = sizeof(gcry_cipher_hd_t),
.key = NULL,
.keysize = 192,
.set_encrypt_key = aes_set_key,
.set_decrypt_key = aes_set_key,
.encrypt = aes_encrypt,
.decrypt = aes_encrypt
},
{
.name = "aes256-ctr",
.blocksize = 16,
.keylen = sizeof(gcry_cipher_hd_t),
.key = NULL,
.keysize = 256,
.set_encrypt_key = aes_set_key,
.set_decrypt_key = aes_set_key,
.encrypt = aes_encrypt,
.decrypt = aes_encrypt
},
{
.name = "aes128-cbc",
.blocksize = 16,
.keylen = sizeof(gcry_cipher_hd_t),
.key = NULL,
.keysize = 128,
.set_encrypt_key = aes_set_key,
.set_decrypt_key = aes_set_key,
.encrypt = aes_encrypt,
.decrypt = aes_decrypt
},
{
.name = "aes192-cbc",
.blocksize = 16,
.keylen = sizeof(gcry_cipher_hd_t),
.key = NULL,
.keysize = 192,
.set_encrypt_key = aes_set_key,
.set_decrypt_key = aes_set_key,
.encrypt = aes_encrypt,
.decrypt = aes_decrypt
},
{
.name = "aes256-cbc",
.blocksize = 16,
.keylen = sizeof(gcry_cipher_hd_t),
.key = NULL,
.keysize = 256,
.set_encrypt_key = aes_set_key,
.set_decrypt_key = aes_set_key,
.encrypt = aes_encrypt,
.decrypt = aes_decrypt
},
{
.name = "aes128-gcm@openssh.com",
.blocksize = 16,
.lenfield_blocksize = 4, /* not encrypted, but authenticated */
.keylen = sizeof(gcry_cipher_hd_t),
.key = NULL,
.keysize = 128,
.tag_size = AES_GCM_TAGLEN,
.set_encrypt_key = aes_set_key,
.set_decrypt_key = aes_set_key,
.aead_encrypt = aes_gcm_encrypt,
.aead_decrypt_length = aes_aead_get_length,
.aead_decrypt = aes_gcm_decrypt,
},
{
.name = "aes256-gcm@openssh.com",
.blocksize = 16,
.lenfield_blocksize = 4, /* not encrypted, but authenticated */
.keylen = sizeof(gcry_cipher_hd_t),
.key = NULL,
.keysize = 256,
.tag_size = AES_GCM_TAGLEN,
.set_encrypt_key = aes_set_key,
.set_decrypt_key = aes_set_key,
.aead_encrypt = aes_gcm_encrypt,
.aead_decrypt_length = aes_aead_get_length,
.aead_decrypt = aes_gcm_decrypt,
},
{
.name = "3des-cbc",
.blocksize = 8,
.keylen = sizeof(gcry_cipher_hd_t),
.key = NULL,
.keysize = 192,
.set_encrypt_key = des3_set_key,
.set_decrypt_key = des3_set_key,
.encrypt = des3_encrypt,
.decrypt = des3_decrypt
},
{
#ifdef HAVE_GCRYPT_CHACHA_POLY
.ciphertype = SSH_AEAD_CHACHA20_POLY1305,
.name = "chacha20-poly1305@openssh.com",
.blocksize = 8,
.lenfield_blocksize = 4,
.keylen = sizeof(struct chacha20_poly1305_keysched),
.keysize = 2 * CHACHA20_KEYLEN * 8,
.tag_size = POLY1305_TAGLEN,
.set_encrypt_key = chacha20_set_encrypt_key,
.set_decrypt_key = chacha20_set_encrypt_key,
.aead_encrypt = chacha20_poly1305_aead_encrypt,
.aead_decrypt_length = chacha20_poly1305_aead_decrypt_length,
.aead_decrypt = chacha20_poly1305_aead_decrypt,
.cleanup = chacha20_cleanup
#else
.name = "chacha20-poly1305@openssh.com"
#endif
},
#ifdef WITH_INSECURE_NONE
{
.name = "none",
.blocksize = 8,
.keysize = 0,
.encrypt = none_crypt,
.decrypt = none_crypt
},
#endif /* WITH_INSECURE_NONE */
{
.name = NULL,
.blocksize = 0,
.keylen = 0,
.key = NULL,
.keysize = 0,
.set_encrypt_key = NULL,
.set_decrypt_key = NULL,
.encrypt = NULL,
.decrypt = NULL
}
};
struct ssh_cipher_struct *ssh_get_ciphertab(void)
{
return ssh_ciphertab;
}
/*
* Extract an MPI from the given s-expression SEXP named NAME which is
* encoded using INFORMAT and store it in a newly allocated ssh_string
* encoded using OUTFORMAT.
*/
ssh_string ssh_sexp_extract_mpi(const gcry_sexp_t sexp,
const char *name,
enum gcry_mpi_format informat,
enum gcry_mpi_format outformat)
{
gpg_error_t err;
ssh_string result = NULL;
gcry_sexp_t fragment = NULL;
gcry_mpi_t mpi = NULL;
size_t size;
fragment = gcry_sexp_find_token(sexp, name, 0);
if (fragment == NULL) {
goto fail;
}
mpi = gcry_sexp_nth_mpi(fragment, 1, informat);
if (mpi == NULL) {
goto fail;
}
err = gcry_mpi_print(outformat, NULL, 0, &size, mpi);
if (err != 0) {
goto fail;
}
result = ssh_string_new(size);
if (result == NULL) {
goto fail;
}
err = gcry_mpi_print(outformat, ssh_string_data(result), size, NULL, mpi);
if (err != 0) {
ssh_string_burn(result);
SSH_STRING_FREE(result);
result = NULL;
goto fail;
}
fail:
gcry_sexp_release(fragment);
gcry_mpi_release(mpi);
return result;
}