forked from Yasushi/putty
-
Notifications
You must be signed in to change notification settings - Fork 6
/
import.c
1993 lines (1795 loc) · 57.8 KB
/
import.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
/*
* Code for PuTTY to import and export private key files in other
* SSH clients' formats.
*/
#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
#include <ctype.h>
#include "putty.h"
#include "ssh.h"
#include "misc.h"
int openssh_encrypted(const Filename *filename);
struct ssh2_userkey *openssh_read(const Filename *filename, char *passphrase,
const char **errmsg_p);
int openssh_write(const Filename *filename, struct ssh2_userkey *key,
char *passphrase);
int sshcom_encrypted(const Filename *filename, char **comment);
struct ssh2_userkey *sshcom_read(const Filename *filename, char *passphrase,
const char **errmsg_p);
int sshcom_write(const Filename *filename, struct ssh2_userkey *key,
char *passphrase);
/*
* Given a key type, determine whether we know how to import it.
*/
int import_possible(int type)
{
if (type == SSH_KEYTYPE_OPENSSH)
return 1;
if (type == SSH_KEYTYPE_SSHCOM)
return 1;
return 0;
}
/*
* Given a key type, determine what native key type
* (SSH_KEYTYPE_SSH1 or SSH_KEYTYPE_SSH2) it will come out as once
* we've imported it.
*/
int import_target_type(int type)
{
/*
* There are no known foreign SSH-1 key formats.
*/
return SSH_KEYTYPE_SSH2;
}
/*
* Determine whether a foreign key is encrypted.
*/
int import_encrypted(const Filename *filename, int type, char **comment)
{
if (type == SSH_KEYTYPE_OPENSSH) {
/* OpenSSH doesn't do key comments */
*comment = dupstr(filename_to_str(filename));
return openssh_encrypted(filename);
}
if (type == SSH_KEYTYPE_SSHCOM) {
return sshcom_encrypted(filename, comment);
}
return 0;
}
/*
* Import an SSH-1 key.
*/
int import_ssh1(const Filename *filename, int type,
struct RSAKey *key, char *passphrase, const char **errmsg_p)
{
return 0;
}
/*
* Import an SSH-2 key.
*/
struct ssh2_userkey *import_ssh2(const Filename *filename, int type,
char *passphrase, const char **errmsg_p)
{
if (type == SSH_KEYTYPE_OPENSSH)
return openssh_read(filename, passphrase, errmsg_p);
if (type == SSH_KEYTYPE_SSHCOM)
return sshcom_read(filename, passphrase, errmsg_p);
return NULL;
}
/*
* Export an SSH-1 key.
*/
int export_ssh1(const Filename *filename, int type, struct RSAKey *key,
char *passphrase)
{
return 0;
}
/*
* Export an SSH-2 key.
*/
int export_ssh2(const Filename *filename, int type,
struct ssh2_userkey *key, char *passphrase)
{
if (type == SSH_KEYTYPE_OPENSSH)
return openssh_write(filename, key, passphrase);
if (type == SSH_KEYTYPE_SSHCOM)
return sshcom_write(filename, key, passphrase);
return 0;
}
/*
* Strip trailing CRs and LFs at the end of a line of text.
*/
void strip_crlf(char *str)
{
char *p = str + strlen(str);
while (p > str && (p[-1] == '\r' || p[-1] == '\n'))
*--p = '\0';
}
/* ----------------------------------------------------------------------
* Helper routines. (The base64 ones are defined in sshpubk.c.)
*/
#define isbase64(c) ( ((c) >= 'A' && (c) <= 'Z') || \
((c) >= 'a' && (c) <= 'z') || \
((c) >= '0' && (c) <= '9') || \
(c) == '+' || (c) == '/' || (c) == '=' \
)
/*
* Read an ASN.1/BER identifier and length pair.
*
* Flags are a combination of the #defines listed below.
*
* Returns -1 if unsuccessful; otherwise returns the number of
* bytes used out of the source data.
*/
/* ASN.1 tag classes. */
#define ASN1_CLASS_UNIVERSAL (0 << 6)
#define ASN1_CLASS_APPLICATION (1 << 6)
#define ASN1_CLASS_CONTEXT_SPECIFIC (2 << 6)
#define ASN1_CLASS_PRIVATE (3 << 6)
#define ASN1_CLASS_MASK (3 << 6)
/* Primitive versus constructed bit. */
#define ASN1_CONSTRUCTED (1 << 5)
static int ber_read_id_len(void *source, int sourcelen,
int *id, int *length, int *flags)
{
unsigned char *p = (unsigned char *) source;
if (sourcelen == 0)
return -1;
*flags = (*p & 0xE0);
if ((*p & 0x1F) == 0x1F) {
*id = 0;
while (*p & 0x80) {
p++, sourcelen--;
if (sourcelen == 0)
return -1;
*id = (*id << 7) | (*p & 0x7F);
}
p++, sourcelen--;
} else {
*id = *p & 0x1F;
p++, sourcelen--;
}
if (sourcelen == 0)
return -1;
if (*p & 0x80) {
int n = *p & 0x7F;
p++, sourcelen--;
if (sourcelen < n)
return -1;
*length = 0;
while (n--)
*length = (*length << 8) | (*p++);
sourcelen -= n;
} else {
*length = *p;
p++, sourcelen--;
}
return p - (unsigned char *) source;
}
/*
* Write an ASN.1/BER identifier and length pair. Returns the
* number of bytes consumed. Assumes dest contains enough space.
* Will avoid writing anything if dest is NULL, but still return
* amount of space required.
*/
static int ber_write_id_len(void *dest, int id, int length, int flags)
{
unsigned char *d = (unsigned char *)dest;
int len = 0;
if (id <= 30) {
/*
* Identifier is one byte.
*/
len++;
if (d) *d++ = id | flags;
} else {
int n;
/*
* Identifier is multiple bytes: the first byte is 11111
* plus the flags, and subsequent bytes encode the value of
* the identifier, 7 bits at a time, with the top bit of
* each byte 1 except the last one which is 0.
*/
len++;
if (d) *d++ = 0x1F | flags;
for (n = 1; (id >> (7*n)) > 0; n++)
continue; /* count the bytes */
while (n--) {
len++;
if (d) *d++ = (n ? 0x80 : 0) | ((id >> (7*n)) & 0x7F);
}
}
if (length < 128) {
/*
* Length is one byte.
*/
len++;
if (d) *d++ = length;
} else {
int n;
/*
* Length is multiple bytes. The first is 0x80 plus the
* number of subsequent bytes, and the subsequent bytes
* encode the actual length.
*/
for (n = 1; (length >> (8*n)) > 0; n++)
continue; /* count the bytes */
len++;
if (d) *d++ = 0x80 | n;
while (n--) {
len++;
if (d) *d++ = (length >> (8*n)) & 0xFF;
}
}
return len;
}
static int put_string(void *target, void *data, int len)
{
unsigned char *d = (unsigned char *)target;
PUT_32BIT(d, len);
memcpy(d+4, data, len);
return len+4;
}
static int put_mp(void *target, void *data, int len)
{
unsigned char *d = (unsigned char *)target;
unsigned char *i = (unsigned char *)data;
if (*i & 0x80) {
PUT_32BIT(d, len+1);
d[4] = 0;
memcpy(d+5, data, len);
return len+5;
} else {
PUT_32BIT(d, len);
memcpy(d+4, data, len);
return len+4;
}
}
/* Simple structure to point to an mp-int within a blob. */
struct mpint_pos { void *start; int bytes; };
static int ssh2_read_mpint(void *data, int len, struct mpint_pos *ret)
{
int bytes;
unsigned char *d = (unsigned char *) data;
if (len < 4)
goto error;
bytes = toint(GET_32BIT(d));
if (bytes < 0 || len-4 < bytes)
goto error;
ret->start = d + 4;
ret->bytes = bytes;
return bytes+4;
error:
ret->start = NULL;
ret->bytes = -1;
return len; /* ensure further calls fail as well */
}
/* ----------------------------------------------------------------------
* Code to read and write OpenSSH private keys.
*/
enum { OSSH_DSA, OSSH_RSA, OSSH_ECDSA };
enum { OSSH_ENC_3DES, OSSH_ENC_AES };
struct openssh_key {
int type;
int encrypted, encryption;
char iv[32];
unsigned char *keyblob;
int keyblob_len, keyblob_size;
};
static struct openssh_key *load_openssh_key(const Filename *filename,
const char **errmsg_p)
{
struct openssh_key *ret;
FILE *fp = NULL;
char *line = NULL;
char *errmsg, *p;
int headers_done;
char base64_bit[4];
int base64_chars = 0;
ret = snew(struct openssh_key);
ret->keyblob = NULL;
ret->keyblob_len = ret->keyblob_size = 0;
ret->encrypted = 0;
memset(ret->iv, 0, sizeof(ret->iv));
fp = f_open(filename, "r", FALSE);
if (!fp) {
errmsg = "unable to open key file";
goto error;
}
if (!(line = fgetline(fp))) {
errmsg = "unexpected end of file";
goto error;
}
strip_crlf(line);
if (0 != strncmp(line, "-----BEGIN ", 11) ||
0 != strcmp(line+strlen(line)-16, "PRIVATE KEY-----")) {
errmsg = "file does not begin with OpenSSH key header";
goto error;
}
if (!strcmp(line, "-----BEGIN RSA PRIVATE KEY-----"))
ret->type = OSSH_RSA;
else if (!strcmp(line, "-----BEGIN DSA PRIVATE KEY-----"))
ret->type = OSSH_DSA;
else if (!strcmp(line, "-----BEGIN EC PRIVATE KEY-----"))
ret->type = OSSH_ECDSA;
else {
errmsg = "unrecognised key type";
goto error;
}
smemclr(line, strlen(line));
sfree(line);
line = NULL;
headers_done = 0;
while (1) {
if (!(line = fgetline(fp))) {
errmsg = "unexpected end of file";
goto error;
}
strip_crlf(line);
if (0 == strncmp(line, "-----END ", 9) &&
0 == strcmp(line+strlen(line)-16, "PRIVATE KEY-----")) {
sfree(line);
line = NULL;
break; /* done */
}
if ((p = strchr(line, ':')) != NULL) {
if (headers_done) {
errmsg = "header found in body of key data";
goto error;
}
*p++ = '\0';
while (*p && isspace((unsigned char)*p)) p++;
if (!strcmp(line, "Proc-Type")) {
if (p[0] != '4' || p[1] != ',') {
errmsg = "Proc-Type is not 4 (only 4 is supported)";
goto error;
}
p += 2;
if (!strcmp(p, "ENCRYPTED"))
ret->encrypted = 1;
} else if (!strcmp(line, "DEK-Info")) {
int i, j, ivlen;
if (!strncmp(p, "DES-EDE3-CBC,", 13)) {
ret->encryption = OSSH_ENC_3DES;
ivlen = 8;
} else if (!strncmp(p, "AES-128-CBC,", 12)) {
ret->encryption = OSSH_ENC_AES;
ivlen = 16;
} else {
errmsg = "unsupported cipher";
goto error;
}
p = strchr(p, ',') + 1;/* always non-NULL, by above checks */
for (i = 0; i < ivlen; i++) {
if (1 != sscanf(p, "%2x", &j)) {
errmsg = "expected more iv data in DEK-Info";
goto error;
}
ret->iv[i] = j;
p += 2;
}
if (*p) {
errmsg = "more iv data than expected in DEK-Info";
goto error;
}
}
} else {
headers_done = 1;
p = line;
while (isbase64(*p)) {
base64_bit[base64_chars++] = *p;
if (base64_chars == 4) {
unsigned char out[3];
int len;
base64_chars = 0;
len = base64_decode_atom(base64_bit, out);
if (len <= 0) {
errmsg = "invalid base64 encoding";
goto error;
}
if (ret->keyblob_len + len > ret->keyblob_size) {
ret->keyblob_size = ret->keyblob_len + len + 256;
ret->keyblob = sresize(ret->keyblob, ret->keyblob_size,
unsigned char);
}
memcpy(ret->keyblob + ret->keyblob_len, out, len);
ret->keyblob_len += len;
smemclr(out, sizeof(out));
}
p++;
}
}
smemclr(line, strlen(line));
sfree(line);
line = NULL;
}
fclose(fp);
fp = NULL;
if (ret->keyblob_len == 0 || !ret->keyblob) {
errmsg = "key body not present";
goto error;
}
if (ret->encrypted && ret->keyblob_len % 8 != 0) {
errmsg = "encrypted key blob is not a multiple of cipher block size";
goto error;
}
smemclr(base64_bit, sizeof(base64_bit));
if (errmsg_p) *errmsg_p = NULL;
return ret;
error:
if (line) {
smemclr(line, strlen(line));
sfree(line);
line = NULL;
}
smemclr(base64_bit, sizeof(base64_bit));
if (ret) {
if (ret->keyblob) {
smemclr(ret->keyblob, ret->keyblob_size);
sfree(ret->keyblob);
}
smemclr(ret, sizeof(*ret));
sfree(ret);
}
if (errmsg_p) *errmsg_p = errmsg;
if (fp) fclose(fp);
return NULL;
}
int openssh_encrypted(const Filename *filename)
{
struct openssh_key *key = load_openssh_key(filename, NULL);
int ret;
if (!key)
return 0;
ret = key->encrypted;
smemclr(key->keyblob, key->keyblob_size);
sfree(key->keyblob);
smemclr(key, sizeof(*key));
sfree(key);
return ret;
}
struct ssh2_userkey *openssh_read(const Filename *filename, char *passphrase,
const char **errmsg_p)
{
struct openssh_key *key = load_openssh_key(filename, errmsg_p);
struct ssh2_userkey *retkey;
unsigned char *p;
int ret, id, len, flags;
int i, num_integers;
struct ssh2_userkey *retval = NULL;
char *errmsg;
unsigned char *blob;
int blobsize = 0, blobptr, privptr;
char *modptr = NULL;
int modlen = 0;
blob = NULL;
if (!key)
return NULL;
if (key->encrypted) {
/*
* Derive encryption key from passphrase and iv/salt:
*
* - let block A equal MD5(passphrase || iv)
* - let block B equal MD5(A || passphrase || iv)
* - block C would be MD5(B || passphrase || iv) and so on
* - encryption key is the first N bytes of A || B
*
* (Note that only 8 bytes of the iv are used for key
* derivation, even when the key is encrypted with AES and
* hence there are 16 bytes available.)
*/
struct MD5Context md5c;
unsigned char keybuf[32];
MD5Init(&md5c);
MD5Update(&md5c, (unsigned char *)passphrase, strlen(passphrase));
MD5Update(&md5c, (unsigned char *)key->iv, 8);
MD5Final(keybuf, &md5c);
MD5Init(&md5c);
MD5Update(&md5c, keybuf, 16);
MD5Update(&md5c, (unsigned char *)passphrase, strlen(passphrase));
MD5Update(&md5c, (unsigned char *)key->iv, 8);
MD5Final(keybuf+16, &md5c);
/*
* Now decrypt the key blob.
*/
if (key->encryption == OSSH_ENC_3DES)
des3_decrypt_pubkey_ossh(keybuf, (unsigned char *)key->iv,
key->keyblob, key->keyblob_len);
else {
void *ctx;
assert(key->encryption == OSSH_ENC_AES);
ctx = aes_make_context();
aes128_key(ctx, keybuf);
aes_iv(ctx, (unsigned char *)key->iv);
aes_ssh2_decrypt_blk(ctx, key->keyblob, key->keyblob_len);
aes_free_context(ctx);
}
smemclr(&md5c, sizeof(md5c));
smemclr(keybuf, sizeof(keybuf));
}
/*
* Now we have a decrypted key blob, which contains an ASN.1
* encoded private key. We must now untangle the ASN.1.
*
* We expect the whole key blob to be formatted as a SEQUENCE
* (0x30 followed by a length code indicating that the rest of
* the blob is part of the sequence). Within that SEQUENCE we
* expect to see a bunch of INTEGERs. What those integers mean
* depends on the key type:
*
* - For RSA, we expect the integers to be 0, n, e, d, p, q,
* dmp1, dmq1, iqmp in that order. (The last three are d mod
* (p-1), d mod (q-1), inverse of q mod p respectively.)
*
* - For DSA, we expect them to be 0, p, q, g, y, x in that
* order.
*
* - In ECDSA the format is totally different: we see the
* SEQUENCE, but beneath is an INTEGER 1, OCTET STRING priv
* EXPLICIT [0] OID curve, EXPLICIT [1] BIT STRING pubPoint
*/
p = key->keyblob;
/* Expect the SEQUENCE header. Take its absence as a failure to
* decrypt, if the key was encrypted. */
ret = ber_read_id_len(p, key->keyblob_len, &id, &len, &flags);
p += ret;
if (ret < 0 || id != 16) {
errmsg = "ASN.1 decoding failure";
retval = key->encrypted ? SSH2_WRONG_PASSPHRASE : NULL;
goto error;
}
/* Expect a load of INTEGERs. */
if (key->type == OSSH_RSA)
num_integers = 9;
else if (key->type == OSSH_DSA)
num_integers = 6;
else
num_integers = 0; /* placate compiler warnings */
if (key->type == OSSH_ECDSA)
{
/* And now for something completely different */
unsigned char *priv;
int privlen;
struct ec_curve *curve;
/* Read INTEGER 1 */
ret = ber_read_id_len(p, key->keyblob+key->keyblob_len-p,
&id, &len, &flags);
p += ret;
if (ret < 0 || id != 2 || key->keyblob+key->keyblob_len-p < len ||
len != 1 || p[0] != 1) {
errmsg = "ASN.1 decoding failure";
retval = key->encrypted ? SSH2_WRONG_PASSPHRASE : NULL;
goto error;
}
p += 1;
/* Read private key OCTET STRING */
ret = ber_read_id_len(p, key->keyblob+key->keyblob_len-p,
&id, &len, &flags);
p += ret;
if (ret < 0 || id != 4 || key->keyblob+key->keyblob_len-p < len) {
errmsg = "ASN.1 decoding failure";
retval = key->encrypted ? SSH2_WRONG_PASSPHRASE : NULL;
goto error;
}
priv = p;
privlen = len;
p += len;
/* Read curve OID */
ret = ber_read_id_len(p, key->keyblob+key->keyblob_len-p,
&id, &len, &flags);
p += ret;
if (ret < 0 || id != 0 || key->keyblob+key->keyblob_len-p < len) {
errmsg = "ASN.1 decoding failure";
retval = key->encrypted ? SSH2_WRONG_PASSPHRASE : NULL;
goto error;
}
ret = ber_read_id_len(p, key->keyblob+key->keyblob_len-p,
&id, &len, &flags);
p += ret;
if (ret < 0 || id != 6 || key->keyblob+key->keyblob_len-p < len) {
errmsg = "ASN.1 decoding failure";
retval = key->encrypted ? SSH2_WRONG_PASSPHRASE : NULL;
goto error;
}
if (len == 8 && !memcmp(p, nistp256_oid, nistp256_oid_len)) {
curve = ec_p256();
} else if (len == 5 && !memcmp(p, nistp384_oid, nistp384_oid_len)) {
curve = ec_p384();
} else if (len == 5 && !memcmp(p, nistp521_oid, nistp521_oid_len)) {
curve = ec_p521();
} else {
errmsg = "Unsupported ECDSA curve.";
retval = NULL;
goto error;
}
p += len;
/* Read BIT STRING point */
ret = ber_read_id_len(p, key->keyblob+key->keyblob_len-p,
&id, &len, &flags);
p += ret;
if (ret < 0 || id != 1 || key->keyblob+key->keyblob_len-p < len) {
errmsg = "ASN.1 decoding failure";
retval = key->encrypted ? SSH2_WRONG_PASSPHRASE : NULL;
goto error;
}
ret = ber_read_id_len(p, key->keyblob+key->keyblob_len-p,
&id, &len, &flags);
p += ret;
if (ret < 0 || id != 3 || key->keyblob+key->keyblob_len-p < len ||
len != ((((curve->fieldBits + 7) / 8) * 2) + 2)) {
errmsg = "ASN.1 decoding failure";
retval = key->encrypted ? SSH2_WRONG_PASSPHRASE : NULL;
goto error;
}
p += 1; len -= 1; /* Skip 0x00 before point */
/* Construct the key */
retkey = snew(struct ssh2_userkey);
if (!retkey) {
errmsg = "out of memory";
goto error;
}
if (curve->fieldBits == 256) {
retkey->alg = &ssh_ecdsa_nistp256;
} else if (curve->fieldBits == 384) {
retkey->alg = &ssh_ecdsa_nistp384;
} else {
retkey->alg = &ssh_ecdsa_nistp521;
}
blob = snewn((4+19 + 4+8 + 4+len) + (4+privlen), unsigned char);
if (!blob) {
sfree(retkey);
errmsg = "out of memory";
goto error;
}
PUT_32BIT(blob, 19);
sprintf((char*)blob+4, "ecdsa-sha2-nistp%d", curve->fieldBits);
PUT_32BIT(blob+4+19, 8);
sprintf((char*)blob+4+19+4, "nistp%d", curve->fieldBits);
PUT_32BIT(blob+4+19+4+8, len);
memcpy(blob+4+19+4+8+4, p, len);
PUT_32BIT(blob+4+19+4+8+4+len, privlen);
memcpy(blob+4+19+4+8+4+len+4, priv, privlen);
retkey->data = retkey->alg->createkey(blob, 4+19+4+8+4+len,
blob+4+19+4+8+4+len, 4+privlen);
if (!retkey->data) {
sfree(retkey);
errmsg = "unable to create key data structure";
goto error;
}
} else if (key->type == OSSH_RSA || key->type == OSSH_DSA) {
/*
* Space to create key blob in.
*/
blobsize = 256+key->keyblob_len;
blob = snewn(blobsize, unsigned char);
PUT_32BIT(blob, 7);
if (key->type == OSSH_DSA)
memcpy(blob+4, "ssh-dss", 7);
else if (key->type == OSSH_RSA)
memcpy(blob+4, "ssh-rsa", 7);
blobptr = 4+7;
privptr = -1;
for (i = 0; i < num_integers; i++) {
ret = ber_read_id_len(p, key->keyblob+key->keyblob_len-p,
&id, &len, &flags);
p += ret;
if (ret < 0 || id != 2 ||
key->keyblob+key->keyblob_len-p < len) {
errmsg = "ASN.1 decoding failure";
retval = key->encrypted ? SSH2_WRONG_PASSPHRASE : NULL;
goto error;
}
if (i == 0) {
/*
* The first integer should be zero always (I think
* this is some sort of version indication).
*/
if (len != 1 || p[0] != 0) {
errmsg = "version number mismatch";
goto error;
}
} else if (key->type == OSSH_RSA) {
/*
* Integers 1 and 2 go into the public blob but in the
* opposite order; integers 3, 4, 5 and 8 go into the
* private blob. The other two (6 and 7) are ignored.
*/
if (i == 1) {
/* Save the details for after we deal with number 2. */
modptr = (char *)p;
modlen = len;
} else if (i != 6 && i != 7) {
PUT_32BIT(blob+blobptr, len);
memcpy(blob+blobptr+4, p, len);
blobptr += 4+len;
if (i == 2) {
PUT_32BIT(blob+blobptr, modlen);
memcpy(blob+blobptr+4, modptr, modlen);
blobptr += 4+modlen;
privptr = blobptr;
}
}
} else if (key->type == OSSH_DSA) {
/*
* Integers 1-4 go into the public blob; integer 5 goes
* into the private blob.
*/
PUT_32BIT(blob+blobptr, len);
memcpy(blob+blobptr+4, p, len);
blobptr += 4+len;
if (i == 4)
privptr = blobptr;
}
/* Skip past the number. */
p += len;
}
/*
* Now put together the actual key. Simplest way to do this is
* to assemble our own key blobs and feed them to the createkey
* functions; this is a bit faffy but it does mean we get all
* the sanity checks for free.
*/
assert(privptr > 0); /* should have bombed by now if not */
retkey = snew(struct ssh2_userkey);
retkey->alg = (key->type == OSSH_RSA ? &ssh_rsa : &ssh_dss);
retkey->data = retkey->alg->createkey(blob, privptr,
blob+privptr, blobptr-privptr);
if (!retkey->data) {
sfree(retkey);
errmsg = "unable to create key data structure";
goto error;
}
} else {
assert(0 && "Bad key type from load_openssh_key");
}
retkey->comment = dupstr("imported-openssh-key");
errmsg = NULL; /* no error */
retval = retkey;
error:
if (blob) {
smemclr(blob, blobsize);
sfree(blob);
}
smemclr(key->keyblob, key->keyblob_size);
sfree(key->keyblob);
smemclr(key, sizeof(*key));
sfree(key);
if (errmsg_p) *errmsg_p = errmsg;
return retval;
}
int openssh_write(const Filename *filename, struct ssh2_userkey *key,
char *passphrase)
{
unsigned char *pubblob, *privblob, *spareblob;
int publen, privlen, sparelen = 0;
unsigned char *outblob;
int outlen;
struct mpint_pos numbers[9];
int nnumbers, pos, len, seqlen, i;
char *header, *footer;
char zero[1];
unsigned char iv[8];
int ret = 0;
FILE *fp;
/*
* Fetch the key blobs.
*/
pubblob = key->alg->public_blob(key->data, &publen);
privblob = key->alg->private_blob(key->data, &privlen);
spareblob = outblob = NULL;
outblob = NULL;
len = 0;
/*
* Encode the OpenSSH key blob, and also decide on the header
* line.
*/
if (key->alg == &ssh_rsa || key->alg == &ssh_dss) {
/*
* The RSA and DSS handlers share some code because the two
* key types have very similar ASN.1 representations, as a
* plain SEQUENCE of big integers. So we set up a list of
* bignums per key type and then construct the actual blob in
* common code after that.
*/
if (key->alg == &ssh_rsa) {
int pos;
struct mpint_pos n, e, d, p, q, iqmp, dmp1, dmq1;
Bignum bd, bp, bq, bdmp1, bdmq1;
/*
* These blobs were generated from inside PuTTY, so we needn't
* treat them as untrusted.
*/
pos = 4 + GET_32BIT(pubblob);
pos += ssh2_read_mpint(pubblob+pos, publen-pos, &e);
pos += ssh2_read_mpint(pubblob+pos, publen-pos, &n);
pos = 0;
pos += ssh2_read_mpint(privblob+pos, privlen-pos, &d);
pos += ssh2_read_mpint(privblob+pos, privlen-pos, &p);
pos += ssh2_read_mpint(privblob+pos, privlen-pos, &q);
pos += ssh2_read_mpint(privblob+pos, privlen-pos, &iqmp);
assert(e.start && iqmp.start); /* can't go wrong */
/* We also need d mod (p-1) and d mod (q-1). */
bd = bignum_from_bytes(d.start, d.bytes);
bp = bignum_from_bytes(p.start, p.bytes);
bq = bignum_from_bytes(q.start, q.bytes);
decbn(bp);
decbn(bq);
bdmp1 = bigmod(bd, bp);
bdmq1 = bigmod(bd, bq);
freebn(bd);
freebn(bp);
freebn(bq);
dmp1.bytes = (bignum_bitcount(bdmp1)+8)/8;
dmq1.bytes = (bignum_bitcount(bdmq1)+8)/8;
sparelen = dmp1.bytes + dmq1.bytes;
spareblob = snewn(sparelen, unsigned char);
dmp1.start = spareblob;
dmq1.start = spareblob + dmp1.bytes;
for (i = 0; i < dmp1.bytes; i++)
spareblob[i] = bignum_byte(bdmp1, dmp1.bytes-1 - i);
for (i = 0; i < dmq1.bytes; i++)
spareblob[i+dmp1.bytes] = bignum_byte(bdmq1, dmq1.bytes-1 - i);
freebn(bdmp1);
freebn(bdmq1);
numbers[0].start = zero; numbers[0].bytes = 1; zero[0] = '\0';
numbers[1] = n;
numbers[2] = e;
numbers[3] = d;
numbers[4] = p;
numbers[5] = q;
numbers[6] = dmp1;
numbers[7] = dmq1;
numbers[8] = iqmp;
nnumbers = 9;
header = "-----BEGIN RSA PRIVATE KEY-----\n";
footer = "-----END RSA PRIVATE KEY-----\n";
} else { /* ssh-dss */
int pos;
struct mpint_pos p, q, g, y, x;
/*
* These blobs were generated from inside PuTTY, so we needn't
* treat them as untrusted.
*/
pos = 4 + GET_32BIT(pubblob);
pos += ssh2_read_mpint(pubblob+pos, publen-pos, &p);
pos += ssh2_read_mpint(pubblob+pos, publen-pos, &q);
pos += ssh2_read_mpint(pubblob+pos, publen-pos, &g);
pos += ssh2_read_mpint(pubblob+pos, publen-pos, &y);
pos = 0;
pos += ssh2_read_mpint(privblob+pos, privlen-pos, &x);
assert(y.start && x.start); /* can't go wrong */
numbers[0].start = zero; numbers[0].bytes = 1; zero[0] = '\0';
numbers[1] = p;
numbers[2] = q;
numbers[3] = g;
numbers[4] = y;
numbers[5] = x;
nnumbers = 6;
header = "-----BEGIN DSA PRIVATE KEY-----\n";
footer = "-----END DSA PRIVATE KEY-----\n";
}
/*
* Now count up the total size of the ASN.1 encoded integers,
* so as to determine the length of the containing SEQUENCE.
*/
len = 0;
for (i = 0; i < nnumbers; i++) {
len += ber_write_id_len(NULL, 2, numbers[i].bytes, 0);
len += numbers[i].bytes;
}
seqlen = len;
/* Now add on the SEQUENCE header. */
len += ber_write_id_len(NULL, 16, seqlen, ASN1_CONSTRUCTED);
/*
* Now we know how big outblob needs to be. Allocate it.
*/
outblob = snewn(len, unsigned char);
/*
* And write the data into it.
*/
pos = 0;
pos += ber_write_id_len(outblob+pos, 16, seqlen, ASN1_CONSTRUCTED);
for (i = 0; i < nnumbers; i++) {
pos += ber_write_id_len(outblob+pos, 2, numbers[i].bytes, 0);
memcpy(outblob+pos, numbers[i].start, numbers[i].bytes);
pos += numbers[i].bytes;
}
} else if (key->alg == &ssh_ecdsa_nistp256 ||
key->alg == &ssh_ecdsa_nistp384 ||