9dda6459 |
1 | /* |
2 | * Code for PuTTY to import and export private key files in other |
3 | * SSH clients' formats. |
4 | */ |
5 | |
6 | #include <stdio.h> |
7 | #include <stdlib.h> |
8 | #include <assert.h> |
9 | #include <ctype.h> |
10 | |
9a30e26b |
11 | #include "putty.h" |
9dda6459 |
12 | #include "ssh.h" |
13 | #include "misc.h" |
14 | |
9a30e26b |
15 | int openssh_encrypted(const Filename *filename); |
1e87cce5 |
16 | struct ssh2_userkey *openssh_read(const Filename *filename, char *passphrase, |
17 | const char **errmsg_p); |
9a30e26b |
18 | int openssh_write(const Filename *filename, struct ssh2_userkey *key, |
19 | char *passphrase); |
9dda6459 |
20 | |
9a30e26b |
21 | int sshcom_encrypted(const Filename *filename, char **comment); |
1e87cce5 |
22 | struct ssh2_userkey *sshcom_read(const Filename *filename, char *passphrase, |
23 | const char **errmsg_p); |
9a30e26b |
24 | int sshcom_write(const Filename *filename, struct ssh2_userkey *key, |
25 | char *passphrase); |
7b4ef1ae |
26 | |
9dda6459 |
27 | /* |
28 | * Given a key type, determine whether we know how to import it. |
29 | */ |
30 | int import_possible(int type) |
31 | { |
32 | if (type == SSH_KEYTYPE_OPENSSH) |
33 | return 1; |
7b4ef1ae |
34 | if (type == SSH_KEYTYPE_SSHCOM) |
35 | return 1; |
9dda6459 |
36 | return 0; |
37 | } |
38 | |
39 | /* |
40 | * Given a key type, determine what native key type |
41 | * (SSH_KEYTYPE_SSH1 or SSH_KEYTYPE_SSH2) it will come out as once |
42 | * we've imported it. |
43 | */ |
44 | int import_target_type(int type) |
45 | { |
46 | /* |
2e85c969 |
47 | * There are no known foreign SSH-1 key formats. |
9dda6459 |
48 | */ |
49 | return SSH_KEYTYPE_SSH2; |
50 | } |
51 | |
52 | /* |
53 | * Determine whether a foreign key is encrypted. |
54 | */ |
9a30e26b |
55 | int import_encrypted(const Filename *filename, int type, char **comment) |
9dda6459 |
56 | { |
57 | if (type == SSH_KEYTYPE_OPENSSH) { |
9a30e26b |
58 | /* OpenSSH doesn't do key comments */ |
9fab77dc |
59 | *comment = dupstr(filename_to_str(filename)); |
9dda6459 |
60 | return openssh_encrypted(filename); |
61 | } |
7b4ef1ae |
62 | if (type == SSH_KEYTYPE_SSHCOM) { |
63 | return sshcom_encrypted(filename, comment); |
64 | } |
9dda6459 |
65 | return 0; |
66 | } |
67 | |
68 | /* |
2e85c969 |
69 | * Import an SSH-1 key. |
9dda6459 |
70 | */ |
9a30e26b |
71 | int import_ssh1(const Filename *filename, int type, |
1e87cce5 |
72 | struct RSAKey *key, char *passphrase, const char **errmsg_p) |
9dda6459 |
73 | { |
74 | return 0; |
75 | } |
76 | |
77 | /* |
2e85c969 |
78 | * Import an SSH-2 key. |
9dda6459 |
79 | */ |
9a30e26b |
80 | struct ssh2_userkey *import_ssh2(const Filename *filename, int type, |
1e87cce5 |
81 | char *passphrase, const char **errmsg_p) |
9dda6459 |
82 | { |
83 | if (type == SSH_KEYTYPE_OPENSSH) |
1e87cce5 |
84 | return openssh_read(filename, passphrase, errmsg_p); |
7b4ef1ae |
85 | if (type == SSH_KEYTYPE_SSHCOM) |
1e87cce5 |
86 | return sshcom_read(filename, passphrase, errmsg_p); |
9dda6459 |
87 | return NULL; |
88 | } |
89 | |
4801c01c |
90 | /* |
2e85c969 |
91 | * Export an SSH-1 key. |
4801c01c |
92 | */ |
9a30e26b |
93 | int export_ssh1(const Filename *filename, int type, struct RSAKey *key, |
94 | char *passphrase) |
4801c01c |
95 | { |
96 | return 0; |
97 | } |
98 | |
99 | /* |
2e85c969 |
100 | * Export an SSH-2 key. |
4801c01c |
101 | */ |
9a30e26b |
102 | int export_ssh2(const Filename *filename, int type, |
4801c01c |
103 | struct ssh2_userkey *key, char *passphrase) |
104 | { |
4801c01c |
105 | if (type == SSH_KEYTYPE_OPENSSH) |
106 | return openssh_write(filename, key, passphrase); |
107 | if (type == SSH_KEYTYPE_SSHCOM) |
108 | return sshcom_write(filename, key, passphrase); |
4801c01c |
109 | return 0; |
110 | } |
111 | |
6ca3d5c6 |
112 | /* |
113 | * Strip trailing CRs and LFs at the end of a line of text. |
114 | */ |
115 | void strip_crlf(char *str) |
116 | { |
117 | char *p = str + strlen(str); |
118 | |
119 | while (p > str && (p[-1] == '\r' || p[-1] == '\n')) |
120 | *--p = '\0'; |
121 | } |
122 | |
9dda6459 |
123 | /* ---------------------------------------------------------------------- |
124 | * Helper routines. (The base64 ones are defined in sshpubk.c.) |
125 | */ |
126 | |
127 | #define isbase64(c) ( ((c) >= 'A' && (c) <= 'Z') || \ |
128 | ((c) >= 'a' && (c) <= 'z') || \ |
129 | ((c) >= '0' && (c) <= '9') || \ |
130 | (c) == '+' || (c) == '/' || (c) == '=' \ |
131 | ) |
132 | |
9dda6459 |
133 | /* |
134 | * Read an ASN.1/BER identifier and length pair. |
135 | * |
136 | * Flags are a combination of the #defines listed below. |
137 | * |
138 | * Returns -1 if unsuccessful; otherwise returns the number of |
139 | * bytes used out of the source data. |
140 | */ |
141 | |
142 | /* ASN.1 tag classes. */ |
143 | #define ASN1_CLASS_UNIVERSAL (0 << 6) |
144 | #define ASN1_CLASS_APPLICATION (1 << 6) |
145 | #define ASN1_CLASS_CONTEXT_SPECIFIC (2 << 6) |
146 | #define ASN1_CLASS_PRIVATE (3 << 6) |
147 | #define ASN1_CLASS_MASK (3 << 6) |
148 | |
149 | /* Primitive versus constructed bit. */ |
150 | #define ASN1_CONSTRUCTED (1 << 5) |
151 | |
d714d740 |
152 | static int ber_read_id_len(void *source, int sourcelen, |
153 | int *id, int *length, int *flags) |
9dda6459 |
154 | { |
155 | unsigned char *p = (unsigned char *) source; |
156 | |
157 | if (sourcelen == 0) |
158 | return -1; |
159 | |
160 | *flags = (*p & 0xE0); |
161 | if ((*p & 0x1F) == 0x1F) { |
162 | *id = 0; |
163 | while (*p & 0x80) { |
9dda6459 |
164 | p++, sourcelen--; |
165 | if (sourcelen == 0) |
166 | return -1; |
3a5a5a59 |
167 | *id = (*id << 7) | (*p & 0x7F); |
9dda6459 |
168 | } |
9dda6459 |
169 | p++, sourcelen--; |
170 | } else { |
171 | *id = *p & 0x1F; |
172 | p++, sourcelen--; |
173 | } |
174 | |
175 | if (sourcelen == 0) |
176 | return -1; |
177 | |
178 | if (*p & 0x80) { |
179 | int n = *p & 0x7F; |
180 | p++, sourcelen--; |
181 | if (sourcelen < n) |
182 | return -1; |
183 | *length = 0; |
184 | while (n--) |
185 | *length = (*length << 8) | (*p++); |
186 | sourcelen -= n; |
187 | } else { |
188 | *length = *p; |
189 | p++, sourcelen--; |
190 | } |
191 | |
192 | return p - (unsigned char *) source; |
193 | } |
194 | |
d23a9b21 |
195 | /* |
196 | * Write an ASN.1/BER identifier and length pair. Returns the |
197 | * number of bytes consumed. Assumes dest contains enough space. |
198 | * Will avoid writing anything if dest is NULL, but still return |
199 | * amount of space required. |
200 | */ |
d714d740 |
201 | static int ber_write_id_len(void *dest, int id, int length, int flags) |
d23a9b21 |
202 | { |
203 | unsigned char *d = (unsigned char *)dest; |
204 | int len = 0; |
205 | |
206 | if (id <= 30) { |
207 | /* |
208 | * Identifier is one byte. |
209 | */ |
210 | len++; |
211 | if (d) *d++ = id | flags; |
212 | } else { |
213 | int n; |
214 | /* |
215 | * Identifier is multiple bytes: the first byte is 11111 |
216 | * plus the flags, and subsequent bytes encode the value of |
217 | * the identifier, 7 bits at a time, with the top bit of |
218 | * each byte 1 except the last one which is 0. |
219 | */ |
220 | len++; |
221 | if (d) *d++ = 0x1F | flags; |
222 | for (n = 1; (id >> (7*n)) > 0; n++) |
223 | continue; /* count the bytes */ |
224 | while (n--) { |
225 | len++; |
226 | if (d) *d++ = (n ? 0x80 : 0) | ((id >> (7*n)) & 0x7F); |
227 | } |
228 | } |
229 | |
230 | if (length < 128) { |
231 | /* |
232 | * Length is one byte. |
233 | */ |
234 | len++; |
235 | if (d) *d++ = length; |
236 | } else { |
237 | int n; |
238 | /* |
239 | * Length is multiple bytes. The first is 0x80 plus the |
240 | * number of subsequent bytes, and the subsequent bytes |
241 | * encode the actual length. |
242 | */ |
243 | for (n = 1; (length >> (8*n)) > 0; n++) |
244 | continue; /* count the bytes */ |
245 | len++; |
246 | if (d) *d++ = 0x80 | n; |
247 | while (n--) { |
248 | len++; |
249 | if (d) *d++ = (length >> (8*n)) & 0xFF; |
250 | } |
251 | } |
252 | |
253 | return len; |
254 | } |
255 | |
7b4ef1ae |
256 | static int put_string(void *target, void *data, int len) |
257 | { |
258 | unsigned char *d = (unsigned char *)target; |
259 | |
260 | PUT_32BIT(d, len); |
261 | memcpy(d+4, data, len); |
262 | return len+4; |
263 | } |
264 | |
265 | static int put_mp(void *target, void *data, int len) |
266 | { |
267 | unsigned char *d = (unsigned char *)target; |
268 | unsigned char *i = (unsigned char *)data; |
269 | |
270 | if (*i & 0x80) { |
271 | PUT_32BIT(d, len+1); |
272 | d[4] = 0; |
273 | memcpy(d+5, data, len); |
274 | return len+5; |
275 | } else { |
276 | PUT_32BIT(d, len); |
277 | memcpy(d+4, data, len); |
278 | return len+4; |
279 | } |
280 | } |
281 | |
d23a9b21 |
282 | /* Simple structure to point to an mp-int within a blob. */ |
283 | struct mpint_pos { void *start; int bytes; }; |
284 | |
d714d740 |
285 | static int ssh2_read_mpint(void *data, int len, struct mpint_pos *ret) |
d23a9b21 |
286 | { |
287 | int bytes; |
288 | unsigned char *d = (unsigned char *) data; |
289 | |
290 | if (len < 4) |
291 | goto error; |
b1650067 |
292 | bytes = toint(GET_32BIT(d)); |
af1da246 |
293 | if (bytes < 0 || len-4 < bytes) |
d23a9b21 |
294 | goto error; |
295 | |
296 | ret->start = d + 4; |
297 | ret->bytes = bytes; |
298 | return bytes+4; |
299 | |
300 | error: |
301 | ret->start = NULL; |
302 | ret->bytes = -1; |
303 | return len; /* ensure further calls fail as well */ |
304 | } |
305 | |
9dda6459 |
306 | /* ---------------------------------------------------------------------- |
d23a9b21 |
307 | * Code to read and write OpenSSH private keys. |
9dda6459 |
308 | */ |
309 | |
310 | enum { OSSH_DSA, OSSH_RSA }; |
06e09f43 |
311 | enum { OSSH_ENC_3DES, OSSH_ENC_AES }; |
9dda6459 |
312 | struct openssh_key { |
313 | int type; |
06e09f43 |
314 | int encrypted, encryption; |
9dda6459 |
315 | char iv[32]; |
316 | unsigned char *keyblob; |
317 | int keyblob_len, keyblob_size; |
318 | }; |
319 | |
1e87cce5 |
320 | static struct openssh_key *load_openssh_key(const Filename *filename, |
321 | const char **errmsg_p) |
9dda6459 |
322 | { |
323 | struct openssh_key *ret; |
ae3ab75a |
324 | FILE *fp = NULL; |
6ca3d5c6 |
325 | char *line = NULL; |
9dda6459 |
326 | char *errmsg, *p; |
327 | int headers_done; |
ee5c1422 |
328 | char base64_bit[4]; |
329 | int base64_chars = 0; |
9dda6459 |
330 | |
3d88e64d |
331 | ret = snew(struct openssh_key); |
9dda6459 |
332 | ret->keyblob = NULL; |
333 | ret->keyblob_len = ret->keyblob_size = 0; |
334 | ret->encrypted = 0; |
335 | memset(ret->iv, 0, sizeof(ret->iv)); |
336 | |
962468d4 |
337 | fp = f_open(filename, "r", FALSE); |
9dda6459 |
338 | if (!fp) { |
1e87cce5 |
339 | errmsg = "unable to open key file"; |
9dda6459 |
340 | goto error; |
341 | } |
6ca3d5c6 |
342 | |
343 | if (!(line = fgetline(fp))) { |
344 | errmsg = "unexpected end of file"; |
345 | goto error; |
346 | } |
347 | strip_crlf(line); |
348 | if (0 != strncmp(line, "-----BEGIN ", 11) || |
349 | 0 != strcmp(line+strlen(line)-16, "PRIVATE KEY-----")) { |
1e87cce5 |
350 | errmsg = "file does not begin with OpenSSH key header"; |
9dda6459 |
351 | goto error; |
352 | } |
6ca3d5c6 |
353 | if (!strcmp(line, "-----BEGIN RSA PRIVATE KEY-----")) |
9dda6459 |
354 | ret->type = OSSH_RSA; |
6ca3d5c6 |
355 | else if (!strcmp(line, "-----BEGIN DSA PRIVATE KEY-----")) |
9dda6459 |
356 | ret->type = OSSH_DSA; |
357 | else { |
1e87cce5 |
358 | errmsg = "unrecognised key type"; |
9dda6459 |
359 | goto error; |
360 | } |
dfb88efd |
361 | smemclr(line, strlen(line)); |
6ca3d5c6 |
362 | sfree(line); |
363 | line = NULL; |
9dda6459 |
364 | |
365 | headers_done = 0; |
366 | while (1) { |
6ca3d5c6 |
367 | if (!(line = fgetline(fp))) { |
1e87cce5 |
368 | errmsg = "unexpected end of file"; |
9dda6459 |
369 | goto error; |
370 | } |
6ca3d5c6 |
371 | strip_crlf(line); |
372 | if (0 == strncmp(line, "-----END ", 9) && |
038ec85e |
373 | 0 == strcmp(line+strlen(line)-16, "PRIVATE KEY-----")) { |
374 | sfree(line); |
fe258273 |
375 | line = NULL; |
9dda6459 |
376 | break; /* done */ |
038ec85e |
377 | } |
6ca3d5c6 |
378 | if ((p = strchr(line, ':')) != NULL) { |
9dda6459 |
379 | if (headers_done) { |
1e87cce5 |
380 | errmsg = "header found in body of key data"; |
9dda6459 |
381 | goto error; |
382 | } |
383 | *p++ = '\0'; |
384 | while (*p && isspace((unsigned char)*p)) p++; |
6ca3d5c6 |
385 | if (!strcmp(line, "Proc-Type")) { |
9dda6459 |
386 | if (p[0] != '4' || p[1] != ',') { |
387 | errmsg = "Proc-Type is not 4 (only 4 is supported)"; |
388 | goto error; |
389 | } |
390 | p += 2; |
6ca3d5c6 |
391 | if (!strcmp(p, "ENCRYPTED")) |
9dda6459 |
392 | ret->encrypted = 1; |
6ca3d5c6 |
393 | } else if (!strcmp(line, "DEK-Info")) { |
06e09f43 |
394 | int i, j, ivlen; |
395 | |
396 | if (!strncmp(p, "DES-EDE3-CBC,", 13)) { |
397 | ret->encryption = OSSH_ENC_3DES; |
398 | ivlen = 8; |
399 | } else if (!strncmp(p, "AES-128-CBC,", 12)) { |
400 | ret->encryption = OSSH_ENC_AES; |
401 | ivlen = 16; |
402 | } else { |
403 | errmsg = "unsupported cipher"; |
9dda6459 |
404 | goto error; |
405 | } |
06e09f43 |
406 | p = strchr(p, ',') + 1;/* always non-NULL, by above checks */ |
407 | for (i = 0; i < ivlen; i++) { |
408 | if (1 != sscanf(p, "%2x", &j)) { |
409 | errmsg = "expected more iv data in DEK-Info"; |
410 | goto error; |
411 | } |
9dda6459 |
412 | ret->iv[i] = j; |
413 | p += 2; |
414 | } |
06e09f43 |
415 | if (*p) { |
416 | errmsg = "more iv data than expected in DEK-Info"; |
9dda6459 |
417 | goto error; |
418 | } |
419 | } |
420 | } else { |
421 | headers_done = 1; |
422 | |
6ca3d5c6 |
423 | p = line; |
ee5c1422 |
424 | while (isbase64(*p)) { |
425 | base64_bit[base64_chars++] = *p; |
426 | if (base64_chars == 4) { |
427 | unsigned char out[3]; |
428 | int len; |
9dda6459 |
429 | |
ee5c1422 |
430 | base64_chars = 0; |
9dda6459 |
431 | |
ee5c1422 |
432 | len = base64_decode_atom(base64_bit, out); |
9dda6459 |
433 | |
ee5c1422 |
434 | if (len <= 0) { |
1e87cce5 |
435 | errmsg = "invalid base64 encoding"; |
ee5c1422 |
436 | goto error; |
437 | } |
438 | |
439 | if (ret->keyblob_len + len > ret->keyblob_size) { |
440 | ret->keyblob_size = ret->keyblob_len + len + 256; |
3d88e64d |
441 | ret->keyblob = sresize(ret->keyblob, ret->keyblob_size, |
442 | unsigned char); |
ee5c1422 |
443 | } |
9dda6459 |
444 | |
ee5c1422 |
445 | memcpy(ret->keyblob + ret->keyblob_len, out, len); |
446 | ret->keyblob_len += len; |
9dda6459 |
447 | |
dfb88efd |
448 | smemclr(out, sizeof(out)); |
ee5c1422 |
449 | } |
9dda6459 |
450 | |
ee5c1422 |
451 | p++; |
9dda6459 |
452 | } |
453 | } |
dfb88efd |
454 | smemclr(line, strlen(line)); |
6ca3d5c6 |
455 | sfree(line); |
456 | line = NULL; |
9dda6459 |
457 | } |
458 | |
ae3ab75a |
459 | fclose(fp); |
460 | fp = NULL; |
461 | |
9dda6459 |
462 | if (ret->keyblob_len == 0 || !ret->keyblob) { |
1e87cce5 |
463 | errmsg = "key body not present"; |
9dda6459 |
464 | goto error; |
465 | } |
466 | |
467 | if (ret->encrypted && ret->keyblob_len % 8 != 0) { |
1e87cce5 |
468 | errmsg = "encrypted key blob is not a multiple of cipher block size"; |
9dda6459 |
469 | goto error; |
470 | } |
471 | |
dfb88efd |
472 | smemclr(base64_bit, sizeof(base64_bit)); |
1e87cce5 |
473 | if (errmsg_p) *errmsg_p = NULL; |
9dda6459 |
474 | return ret; |
475 | |
476 | error: |
6ca3d5c6 |
477 | if (line) { |
dfb88efd |
478 | smemclr(line, strlen(line)); |
6ca3d5c6 |
479 | sfree(line); |
480 | line = NULL; |
481 | } |
dfb88efd |
482 | smemclr(base64_bit, sizeof(base64_bit)); |
9dda6459 |
483 | if (ret) { |
ee5c1422 |
484 | if (ret->keyblob) { |
dfb88efd |
485 | smemclr(ret->keyblob, ret->keyblob_size); |
ee5c1422 |
486 | sfree(ret->keyblob); |
487 | } |
dfb88efd |
488 | smemclr(ret, sizeof(*ret)); |
9dda6459 |
489 | sfree(ret); |
490 | } |
1e87cce5 |
491 | if (errmsg_p) *errmsg_p = errmsg; |
ae3ab75a |
492 | if (fp) fclose(fp); |
9dda6459 |
493 | return NULL; |
494 | } |
495 | |
9a30e26b |
496 | int openssh_encrypted(const Filename *filename) |
9dda6459 |
497 | { |
1e87cce5 |
498 | struct openssh_key *key = load_openssh_key(filename, NULL); |
9dda6459 |
499 | int ret; |
500 | |
501 | if (!key) |
502 | return 0; |
503 | ret = key->encrypted; |
dfb88efd |
504 | smemclr(key->keyblob, key->keyblob_size); |
9dda6459 |
505 | sfree(key->keyblob); |
dfb88efd |
506 | smemclr(key, sizeof(*key)); |
9dda6459 |
507 | sfree(key); |
508 | return ret; |
509 | } |
510 | |
1e87cce5 |
511 | struct ssh2_userkey *openssh_read(const Filename *filename, char *passphrase, |
512 | const char **errmsg_p) |
9dda6459 |
513 | { |
1e87cce5 |
514 | struct openssh_key *key = load_openssh_key(filename, errmsg_p); |
9dda6459 |
515 | struct ssh2_userkey *retkey; |
516 | unsigned char *p; |
517 | int ret, id, len, flags; |
518 | int i, num_integers; |
519 | struct ssh2_userkey *retval = NULL; |
520 | char *errmsg; |
521 | unsigned char *blob; |
224f397a |
522 | int blobsize = 0, blobptr, privptr; |
523 | char *modptr = NULL; |
524 | int modlen = 0; |
9dda6459 |
525 | |
e3498db5 |
526 | blob = NULL; |
527 | |
9dda6459 |
528 | if (!key) |
529 | return NULL; |
530 | |
531 | if (key->encrypted) { |
532 | /* |
533 | * Derive encryption key from passphrase and iv/salt: |
534 | * |
535 | * - let block A equal MD5(passphrase || iv) |
536 | * - let block B equal MD5(A || passphrase || iv) |
537 | * - block C would be MD5(B || passphrase || iv) and so on |
538 | * - encryption key is the first N bytes of A || B |
91eea944 |
539 | * |
540 | * (Note that only 8 bytes of the iv are used for key |
541 | * derivation, even when the key is encrypted with AES and |
542 | * hence there are 16 bytes available.) |
9dda6459 |
543 | */ |
544 | struct MD5Context md5c; |
545 | unsigned char keybuf[32]; |
546 | |
547 | MD5Init(&md5c); |
201188af |
548 | MD5Update(&md5c, (unsigned char *)passphrase, strlen(passphrase)); |
549 | MD5Update(&md5c, (unsigned char *)key->iv, 8); |
9dda6459 |
550 | MD5Final(keybuf, &md5c); |
551 | |
552 | MD5Init(&md5c); |
553 | MD5Update(&md5c, keybuf, 16); |
201188af |
554 | MD5Update(&md5c, (unsigned char *)passphrase, strlen(passphrase)); |
555 | MD5Update(&md5c, (unsigned char *)key->iv, 8); |
9dda6459 |
556 | MD5Final(keybuf+16, &md5c); |
557 | |
558 | /* |
559 | * Now decrypt the key blob. |
560 | */ |
06e09f43 |
561 | if (key->encryption == OSSH_ENC_3DES) |
562 | des3_decrypt_pubkey_ossh(keybuf, (unsigned char *)key->iv, |
563 | key->keyblob, key->keyblob_len); |
564 | else { |
565 | void *ctx; |
566 | assert(key->encryption == OSSH_ENC_AES); |
567 | ctx = aes_make_context(); |
568 | aes128_key(ctx, keybuf); |
569 | aes_iv(ctx, (unsigned char *)key->iv); |
570 | aes_ssh2_decrypt_blk(ctx, key->keyblob, key->keyblob_len); |
571 | aes_free_context(ctx); |
572 | } |
ee5c1422 |
573 | |
dfb88efd |
574 | smemclr(&md5c, sizeof(md5c)); |
575 | smemclr(keybuf, sizeof(keybuf)); |
9dda6459 |
576 | } |
577 | |
578 | /* |
579 | * Now we have a decrypted key blob, which contains an ASN.1 |
580 | * encoded private key. We must now untangle the ASN.1. |
581 | * |
582 | * We expect the whole key blob to be formatted as a SEQUENCE |
583 | * (0x30 followed by a length code indicating that the rest of |
584 | * the blob is part of the sequence). Within that SEQUENCE we |
585 | * expect to see a bunch of INTEGERs. What those integers mean |
586 | * depends on the key type: |
587 | * |
588 | * - For RSA, we expect the integers to be 0, n, e, d, p, q, |
589 | * dmp1, dmq1, iqmp in that order. (The last three are d mod |
590 | * (p-1), d mod (q-1), inverse of q mod p respectively.) |
591 | * |
592 | * - For DSA, we expect them to be 0, p, q, g, y, x in that |
593 | * order. |
594 | */ |
595 | |
596 | p = key->keyblob; |
597 | |
cf77c10b |
598 | /* Expect the SEQUENCE header. Take its absence as a failure to |
599 | * decrypt, if the key was encrypted. */ |
9dda6459 |
600 | ret = ber_read_id_len(p, key->keyblob_len, &id, &len, &flags); |
601 | p += ret; |
602 | if (ret < 0 || id != 16) { |
603 | errmsg = "ASN.1 decoding failure"; |
cf77c10b |
604 | retval = key->encrypted ? SSH2_WRONG_PASSPHRASE : NULL; |
9dda6459 |
605 | goto error; |
606 | } |
607 | |
608 | /* Expect a load of INTEGERs. */ |
609 | if (key->type == OSSH_RSA) |
610 | num_integers = 9; |
611 | else if (key->type == OSSH_DSA) |
612 | num_integers = 6; |
224f397a |
613 | else |
614 | num_integers = 0; /* placate compiler warnings */ |
9dda6459 |
615 | |
616 | /* |
617 | * Space to create key blob in. |
618 | */ |
ee5c1422 |
619 | blobsize = 256+key->keyblob_len; |
3d88e64d |
620 | blob = snewn(blobsize, unsigned char); |
9dda6459 |
621 | PUT_32BIT(blob, 7); |
622 | if (key->type == OSSH_DSA) |
623 | memcpy(blob+4, "ssh-dss", 7); |
624 | else if (key->type == OSSH_RSA) |
625 | memcpy(blob+4, "ssh-rsa", 7); |
626 | blobptr = 4+7; |
627 | privptr = -1; |
628 | |
629 | for (i = 0; i < num_integers; i++) { |
630 | ret = ber_read_id_len(p, key->keyblob+key->keyblob_len-p, |
631 | &id, &len, &flags); |
632 | p += ret; |
633 | if (ret < 0 || id != 2 || |
634 | key->keyblob+key->keyblob_len-p < len) { |
635 | errmsg = "ASN.1 decoding failure"; |
cf77c10b |
636 | retval = key->encrypted ? SSH2_WRONG_PASSPHRASE : NULL; |
9dda6459 |
637 | goto error; |
638 | } |
639 | |
640 | if (i == 0) { |
641 | /* |
642 | * The first integer should be zero always (I think |
643 | * this is some sort of version indication). |
644 | */ |
645 | if (len != 1 || p[0] != 0) { |
1e87cce5 |
646 | errmsg = "version number mismatch"; |
9dda6459 |
647 | goto error; |
648 | } |
649 | } else if (key->type == OSSH_RSA) { |
650 | /* |
651 | * Integers 1 and 2 go into the public blob but in the |
652 | * opposite order; integers 3, 4, 5 and 8 go into the |
653 | * private blob. The other two (6 and 7) are ignored. |
654 | */ |
655 | if (i == 1) { |
656 | /* Save the details for after we deal with number 2. */ |
201188af |
657 | modptr = (char *)p; |
9dda6459 |
658 | modlen = len; |
659 | } else if (i != 6 && i != 7) { |
660 | PUT_32BIT(blob+blobptr, len); |
661 | memcpy(blob+blobptr+4, p, len); |
662 | blobptr += 4+len; |
663 | if (i == 2) { |
664 | PUT_32BIT(blob+blobptr, modlen); |
665 | memcpy(blob+blobptr+4, modptr, modlen); |
666 | blobptr += 4+modlen; |
667 | privptr = blobptr; |
668 | } |
669 | } |
670 | } else if (key->type == OSSH_DSA) { |
671 | /* |
672 | * Integers 1-4 go into the public blob; integer 5 goes |
673 | * into the private blob. |
674 | */ |
675 | PUT_32BIT(blob+blobptr, len); |
676 | memcpy(blob+blobptr+4, p, len); |
677 | blobptr += 4+len; |
678 | if (i == 4) |
679 | privptr = blobptr; |
680 | } |
681 | |
682 | /* Skip past the number. */ |
683 | p += len; |
684 | } |
685 | |
686 | /* |
687 | * Now put together the actual key. Simplest way to do this is |
688 | * to assemble our own key blobs and feed them to the createkey |
689 | * functions; this is a bit faffy but it does mean we get all |
690 | * the sanity checks for free. |
691 | */ |
692 | assert(privptr > 0); /* should have bombed by now if not */ |
3d88e64d |
693 | retkey = snew(struct ssh2_userkey); |
9dda6459 |
694 | retkey->alg = (key->type == OSSH_RSA ? &ssh_rsa : &ssh_dss); |
695 | retkey->data = retkey->alg->createkey(blob, privptr, |
696 | blob+privptr, blobptr-privptr); |
697 | if (!retkey->data) { |
698 | sfree(retkey); |
699 | errmsg = "unable to create key data structure"; |
700 | goto error; |
701 | } |
702 | |
703 | retkey->comment = dupstr("imported-openssh-key"); |
ee5c1422 |
704 | errmsg = NULL; /* no error */ |
705 | retval = retkey; |
9dda6459 |
706 | |
707 | error: |
ee5c1422 |
708 | if (blob) { |
dfb88efd |
709 | smemclr(blob, blobsize); |
ee5c1422 |
710 | sfree(blob); |
711 | } |
dfb88efd |
712 | smemclr(key->keyblob, key->keyblob_size); |
9dda6459 |
713 | sfree(key->keyblob); |
dfb88efd |
714 | smemclr(key, sizeof(*key)); |
9dda6459 |
715 | sfree(key); |
1e87cce5 |
716 | if (errmsg_p) *errmsg_p = errmsg; |
9dda6459 |
717 | return retval; |
718 | } |
7b4ef1ae |
719 | |
9a30e26b |
720 | int openssh_write(const Filename *filename, struct ssh2_userkey *key, |
721 | char *passphrase) |
d23a9b21 |
722 | { |
723 | unsigned char *pubblob, *privblob, *spareblob; |
224f397a |
724 | int publen, privlen, sparelen = 0; |
d23a9b21 |
725 | unsigned char *outblob; |
726 | int outlen; |
727 | struct mpint_pos numbers[9]; |
728 | int nnumbers, pos, len, seqlen, i; |
729 | char *header, *footer; |
730 | char zero[1]; |
731 | unsigned char iv[8]; |
732 | int ret = 0; |
733 | FILE *fp; |
734 | |
735 | /* |
736 | * Fetch the key blobs. |
737 | */ |
738 | pubblob = key->alg->public_blob(key->data, &publen); |
739 | privblob = key->alg->private_blob(key->data, &privlen); |
740 | spareblob = outblob = NULL; |
741 | |
742 | /* |
743 | * Find the sequence of integers to be encoded into the OpenSSH |
744 | * key blob, and also decide on the header line. |
745 | */ |
746 | if (key->alg == &ssh_rsa) { |
747 | int pos; |
748 | struct mpint_pos n, e, d, p, q, iqmp, dmp1, dmq1; |
749 | Bignum bd, bp, bq, bdmp1, bdmq1; |
750 | |
b1650067 |
751 | /* |
752 | * These blobs were generated from inside PuTTY, so we needn't |
753 | * treat them as untrusted. |
754 | */ |
d23a9b21 |
755 | pos = 4 + GET_32BIT(pubblob); |
756 | pos += ssh2_read_mpint(pubblob+pos, publen-pos, &e); |
757 | pos += ssh2_read_mpint(pubblob+pos, publen-pos, &n); |
758 | pos = 0; |
759 | pos += ssh2_read_mpint(privblob+pos, privlen-pos, &d); |
760 | pos += ssh2_read_mpint(privblob+pos, privlen-pos, &p); |
761 | pos += ssh2_read_mpint(privblob+pos, privlen-pos, &q); |
762 | pos += ssh2_read_mpint(privblob+pos, privlen-pos, &iqmp); |
763 | |
764 | assert(e.start && iqmp.start); /* can't go wrong */ |
765 | |
766 | /* We also need d mod (p-1) and d mod (q-1). */ |
767 | bd = bignum_from_bytes(d.start, d.bytes); |
768 | bp = bignum_from_bytes(p.start, p.bytes); |
769 | bq = bignum_from_bytes(q.start, q.bytes); |
770 | decbn(bp); |
771 | decbn(bq); |
772 | bdmp1 = bigmod(bd, bp); |
773 | bdmq1 = bigmod(bd, bq); |
774 | freebn(bd); |
775 | freebn(bp); |
776 | freebn(bq); |
777 | |
778 | dmp1.bytes = (bignum_bitcount(bdmp1)+8)/8; |
779 | dmq1.bytes = (bignum_bitcount(bdmq1)+8)/8; |
780 | sparelen = dmp1.bytes + dmq1.bytes; |
3d88e64d |
781 | spareblob = snewn(sparelen, unsigned char); |
d23a9b21 |
782 | dmp1.start = spareblob; |
783 | dmq1.start = spareblob + dmp1.bytes; |
784 | for (i = 0; i < dmp1.bytes; i++) |
785 | spareblob[i] = bignum_byte(bdmp1, dmp1.bytes-1 - i); |
786 | for (i = 0; i < dmq1.bytes; i++) |
787 | spareblob[i+dmp1.bytes] = bignum_byte(bdmq1, dmq1.bytes-1 - i); |
788 | freebn(bdmp1); |
789 | freebn(bdmq1); |
790 | |
791 | numbers[0].start = zero; numbers[0].bytes = 1; zero[0] = '\0'; |
792 | numbers[1] = n; |
793 | numbers[2] = e; |
794 | numbers[3] = d; |
795 | numbers[4] = p; |
796 | numbers[5] = q; |
797 | numbers[6] = dmp1; |
798 | numbers[7] = dmq1; |
799 | numbers[8] = iqmp; |
800 | |
801 | nnumbers = 9; |
802 | header = "-----BEGIN RSA PRIVATE KEY-----\n"; |
803 | footer = "-----END RSA PRIVATE KEY-----\n"; |
804 | } else if (key->alg == &ssh_dss) { |
805 | int pos; |
806 | struct mpint_pos p, q, g, y, x; |
807 | |
b1650067 |
808 | /* |
809 | * These blobs were generated from inside PuTTY, so we needn't |
810 | * treat them as untrusted. |
811 | */ |
d23a9b21 |
812 | pos = 4 + GET_32BIT(pubblob); |
813 | pos += ssh2_read_mpint(pubblob+pos, publen-pos, &p); |
814 | pos += ssh2_read_mpint(pubblob+pos, publen-pos, &q); |
815 | pos += ssh2_read_mpint(pubblob+pos, publen-pos, &g); |
816 | pos += ssh2_read_mpint(pubblob+pos, publen-pos, &y); |
817 | pos = 0; |
818 | pos += ssh2_read_mpint(privblob+pos, privlen-pos, &x); |
819 | |
820 | assert(y.start && x.start); /* can't go wrong */ |
821 | |
822 | numbers[0].start = zero; numbers[0].bytes = 1; zero[0] = '\0'; |
823 | numbers[1] = p; |
824 | numbers[2] = q; |
825 | numbers[3] = g; |
826 | numbers[4] = y; |
827 | numbers[5] = x; |
828 | |
829 | nnumbers = 6; |
830 | header = "-----BEGIN DSA PRIVATE KEY-----\n"; |
831 | footer = "-----END DSA PRIVATE KEY-----\n"; |
832 | } else { |
833 | assert(0); /* zoinks! */ |
8815b68b |
834 | exit(1); /* XXX: GCC doesn't understand assert() on some systems. */ |
d23a9b21 |
835 | } |
836 | |
837 | /* |
838 | * Now count up the total size of the ASN.1 encoded integers, |
839 | * so as to determine the length of the containing SEQUENCE. |
840 | */ |
841 | len = 0; |
842 | for (i = 0; i < nnumbers; i++) { |
843 | len += ber_write_id_len(NULL, 2, numbers[i].bytes, 0); |
844 | len += numbers[i].bytes; |
845 | } |
846 | seqlen = len; |
847 | /* Now add on the SEQUENCE header. */ |
848 | len += ber_write_id_len(NULL, 16, seqlen, ASN1_CONSTRUCTED); |
04627c33 |
849 | /* Round up to the cipher block size, ensuring we have at least one |
850 | * byte of padding (see below). */ |
851 | outlen = len; |
d23a9b21 |
852 | if (passphrase) |
04627c33 |
853 | outlen = (outlen+8) &~ 7; |
d23a9b21 |
854 | |
855 | /* |
856 | * Now we know how big outblob needs to be. Allocate it. |
857 | */ |
3d88e64d |
858 | outblob = snewn(outlen, unsigned char); |
d23a9b21 |
859 | |
860 | /* |
861 | * And write the data into it. |
862 | */ |
863 | pos = 0; |
864 | pos += ber_write_id_len(outblob+pos, 16, seqlen, ASN1_CONSTRUCTED); |
865 | for (i = 0; i < nnumbers; i++) { |
866 | pos += ber_write_id_len(outblob+pos, 2, numbers[i].bytes, 0); |
867 | memcpy(outblob+pos, numbers[i].start, numbers[i].bytes); |
868 | pos += numbers[i].bytes; |
869 | } |
04627c33 |
870 | |
871 | /* |
872 | * Padding on OpenSSH keys is deterministic. The number of |
873 | * padding bytes is always more than zero, and always at most |
874 | * the cipher block length. The value of each padding byte is |
875 | * equal to the number of padding bytes. So a plaintext that's |
876 | * an exact multiple of the block size will be padded with 08 |
877 | * 08 08 08 08 08 08 08 (assuming a 64-bit block cipher); a |
878 | * plaintext one byte less than a multiple of the block size |
879 | * will be padded with just 01. |
880 | * |
881 | * This enables the OpenSSL key decryption function to strip |
882 | * off the padding algorithmically and return the unpadded |
883 | * plaintext to the next layer: it looks at the final byte, and |
884 | * then expects to find that many bytes at the end of the data |
885 | * with the same value. Those are all removed and the rest is |
886 | * returned. |
887 | */ |
888 | assert(pos == len); |
d23a9b21 |
889 | while (pos < outlen) { |
04627c33 |
890 | outblob[pos++] = outlen - len; |
d23a9b21 |
891 | } |
892 | |
893 | /* |
894 | * Encrypt the key. |
91eea944 |
895 | * |
896 | * For the moment, we still encrypt our OpenSSH keys using |
897 | * old-style 3DES. |
d23a9b21 |
898 | */ |
899 | if (passphrase) { |
900 | /* |
901 | * Invent an iv. Then derive encryption key from passphrase |
902 | * and iv/salt: |
903 | * |
904 | * - let block A equal MD5(passphrase || iv) |
905 | * - let block B equal MD5(A || passphrase || iv) |
906 | * - block C would be MD5(B || passphrase || iv) and so on |
907 | * - encryption key is the first N bytes of A || B |
908 | */ |
909 | struct MD5Context md5c; |
910 | unsigned char keybuf[32]; |
911 | |
912 | for (i = 0; i < 8; i++) iv[i] = random_byte(); |
913 | |
914 | MD5Init(&md5c); |
201188af |
915 | MD5Update(&md5c, (unsigned char *)passphrase, strlen(passphrase)); |
d23a9b21 |
916 | MD5Update(&md5c, iv, 8); |
917 | MD5Final(keybuf, &md5c); |
918 | |
919 | MD5Init(&md5c); |
920 | MD5Update(&md5c, keybuf, 16); |
201188af |
921 | MD5Update(&md5c, (unsigned char *)passphrase, strlen(passphrase)); |
d23a9b21 |
922 | MD5Update(&md5c, iv, 8); |
923 | MD5Final(keybuf+16, &md5c); |
924 | |
925 | /* |
926 | * Now encrypt the key blob. |
927 | */ |
928 | des3_encrypt_pubkey_ossh(keybuf, iv, outblob, outlen); |
929 | |
dfb88efd |
930 | smemclr(&md5c, sizeof(md5c)); |
931 | smemclr(keybuf, sizeof(keybuf)); |
d23a9b21 |
932 | } |
933 | |
934 | /* |
935 | * And save it. We'll use Unix line endings just in case it's |
936 | * subsequently transferred in binary mode. |
937 | */ |
962468d4 |
938 | fp = f_open(filename, "wb", TRUE); /* ensure Unix line endings */ |
d23a9b21 |
939 | if (!fp) |
940 | goto error; |
941 | fputs(header, fp); |
942 | if (passphrase) { |
943 | fprintf(fp, "Proc-Type: 4,ENCRYPTED\nDEK-Info: DES-EDE3-CBC,"); |
944 | for (i = 0; i < 8; i++) |
945 | fprintf(fp, "%02X", iv[i]); |
946 | fprintf(fp, "\n\n"); |
947 | } |
96d19bc9 |
948 | base64_encode(fp, outblob, outlen, 64); |
d23a9b21 |
949 | fputs(footer, fp); |
950 | fclose(fp); |
951 | ret = 1; |
952 | |
953 | error: |
954 | if (outblob) { |
dfb88efd |
955 | smemclr(outblob, outlen); |
d23a9b21 |
956 | sfree(outblob); |
957 | } |
958 | if (spareblob) { |
dfb88efd |
959 | smemclr(spareblob, sparelen); |
d23a9b21 |
960 | sfree(spareblob); |
961 | } |
962 | if (privblob) { |
dfb88efd |
963 | smemclr(privblob, privlen); |
d23a9b21 |
964 | sfree(privblob); |
965 | } |
966 | if (pubblob) { |
dfb88efd |
967 | smemclr(pubblob, publen); |
d23a9b21 |
968 | sfree(pubblob); |
969 | } |
970 | return ret; |
971 | } |
972 | |
7b4ef1ae |
973 | /* ---------------------------------------------------------------------- |
974 | * Code to read ssh.com private keys. |
975 | */ |
976 | |
977 | /* |
2e85c969 |
978 | * The format of the base64 blob is largely SSH-2-packet-formatted, |
7b4ef1ae |
979 | * except that mpints are a bit different: they're more like the |
2e85c969 |
980 | * old SSH-1 mpint. You have a 32-bit bit count N, followed by |
7b4ef1ae |
981 | * (N+7)/8 bytes of data. |
982 | * |
983 | * So. The blob contains: |
984 | * |
985 | * - uint32 0x3f6ff9eb (magic number) |
986 | * - uint32 size (total blob size) |
987 | * - string key-type (see below) |
988 | * - string cipher-type (tells you if key is encrypted) |
989 | * - string encrypted-blob |
990 | * |
991 | * (The first size field includes the size field itself and the |
2e85c969 |
992 | * magic number before it. All other size fields are ordinary SSH-2 |
7b4ef1ae |
993 | * strings, so the size field indicates how much data is to |
994 | * _follow_.) |
995 | * |
996 | * The encrypted blob, once decrypted, contains a single string |
997 | * which in turn contains the payload. (This allows padding to be |
998 | * added after that string while still making it clear where the |
999 | * real payload ends. Also it probably makes for a reasonable |
1000 | * decryption check.) |
1001 | * |
1002 | * The payload blob, for an RSA key, contains: |
1003 | * - mpint e |
1004 | * - mpint d |
1005 | * - mpint n (yes, the public and private stuff is intermixed) |
1006 | * - mpint u (presumably inverse of p mod q) |
1007 | * - mpint p (p is the smaller prime) |
1008 | * - mpint q (q is the larger) |
1009 | * |
1010 | * For a DSA key, the payload blob contains: |
1011 | * - uint32 0 |
1012 | * - mpint p |
1013 | * - mpint g |
1014 | * - mpint q |
1015 | * - mpint y |
1016 | * - mpint x |
1017 | * |
1018 | * Alternatively, if the parameters are `predefined', that |
1019 | * (0,p,g,q) sequence can be replaced by a uint32 1 and a string |
1020 | * containing some predefined parameter specification. *shudder*, |
1021 | * but I doubt we'll encounter this in real life. |
1022 | * |
1023 | * The key type strings are ghastly. The RSA key I looked at had a |
1024 | * type string of |
1025 | * |
1026 | * `if-modn{sign{rsa-pkcs1-sha1},encrypt{rsa-pkcs1v2-oaep}}' |
1027 | * |
1028 | * and the DSA key wasn't much better: |
1029 | * |
1030 | * `dl-modp{sign{dsa-nist-sha1},dh{plain}}' |
1031 | * |
1032 | * It isn't clear that these will always be the same. I think it |
1033 | * might be wise just to look at the `if-modn{sign{rsa' and |
1034 | * `dl-modp{sign{dsa' prefixes. |
1035 | * |
1036 | * Finally, the encryption. The cipher-type string appears to be |
2e85c969 |
1037 | * either `none' or `3des-cbc'. Looks as if this is SSH-2-style |
7b4ef1ae |
1038 | * 3des-cbc (i.e. outer cbc rather than inner). The key is created |
1039 | * from the passphrase by means of yet another hashing faff: |
1040 | * |
1041 | * - first 16 bytes are MD5(passphrase) |
1042 | * - next 16 bytes are MD5(passphrase || first 16 bytes) |
1043 | * - if there were more, they'd be MD5(passphrase || first 32), |
1044 | * and so on. |
1045 | */ |
1046 | |
96d19bc9 |
1047 | #define SSHCOM_MAGIC_NUMBER 0x3f6ff9eb |
1048 | |
7b4ef1ae |
1049 | struct sshcom_key { |
1050 | char comment[256]; /* allowing any length is overkill */ |
1051 | unsigned char *keyblob; |
1052 | int keyblob_len, keyblob_size; |
1053 | }; |
1054 | |
1e87cce5 |
1055 | static struct sshcom_key *load_sshcom_key(const Filename *filename, |
1056 | const char **errmsg_p) |
7b4ef1ae |
1057 | { |
1058 | struct sshcom_key *ret; |
1059 | FILE *fp; |
6ca3d5c6 |
1060 | char *line = NULL; |
1061 | int hdrstart, len; |
7b4ef1ae |
1062 | char *errmsg, *p; |
1063 | int headers_done; |
1064 | char base64_bit[4]; |
1065 | int base64_chars = 0; |
1066 | |
3d88e64d |
1067 | ret = snew(struct sshcom_key); |
7b4ef1ae |
1068 | ret->comment[0] = '\0'; |
1069 | ret->keyblob = NULL; |
1070 | ret->keyblob_len = ret->keyblob_size = 0; |
1071 | |
962468d4 |
1072 | fp = f_open(filename, "r", FALSE); |
7b4ef1ae |
1073 | if (!fp) { |
1e87cce5 |
1074 | errmsg = "unable to open key file"; |
7b4ef1ae |
1075 | goto error; |
1076 | } |
6ca3d5c6 |
1077 | if (!(line = fgetline(fp))) { |
1078 | errmsg = "unexpected end of file"; |
1079 | goto error; |
1080 | } |
1081 | strip_crlf(line); |
1082 | if (0 != strcmp(line, "---- BEGIN SSH2 ENCRYPTED PRIVATE KEY ----")) { |
1e87cce5 |
1083 | errmsg = "file does not begin with ssh.com key header"; |
7b4ef1ae |
1084 | goto error; |
1085 | } |
dfb88efd |
1086 | smemclr(line, strlen(line)); |
6ca3d5c6 |
1087 | sfree(line); |
1088 | line = NULL; |
7b4ef1ae |
1089 | |
1090 | headers_done = 0; |
1091 | while (1) { |
6ca3d5c6 |
1092 | if (!(line = fgetline(fp))) { |
1e87cce5 |
1093 | errmsg = "unexpected end of file"; |
7b4ef1ae |
1094 | goto error; |
1095 | } |
6ca3d5c6 |
1096 | strip_crlf(line); |
038ec85e |
1097 | if (!strcmp(line, "---- END SSH2 ENCRYPTED PRIVATE KEY ----")) { |
1098 | sfree(line); |
fe258273 |
1099 | line = NULL; |
7b4ef1ae |
1100 | break; /* done */ |
038ec85e |
1101 | } |
6ca3d5c6 |
1102 | if ((p = strchr(line, ':')) != NULL) { |
7b4ef1ae |
1103 | if (headers_done) { |
1e87cce5 |
1104 | errmsg = "header found in body of key data"; |
7b4ef1ae |
1105 | goto error; |
1106 | } |
1107 | *p++ = '\0'; |
1108 | while (*p && isspace((unsigned char)*p)) p++; |
6ca3d5c6 |
1109 | hdrstart = p - line; |
1110 | |
7b4ef1ae |
1111 | /* |
1112 | * Header lines can end in a trailing backslash for |
1113 | * continuation. |
1114 | */ |
6ca3d5c6 |
1115 | len = hdrstart + strlen(line+hdrstart); |
1116 | assert(!line[len]); |
1117 | while (line[len-1] == '\\') { |
1118 | char *line2; |
1119 | int line2len; |
1120 | |
1121 | line2 = fgetline(fp); |
1122 | if (!line2) { |
1e87cce5 |
1123 | errmsg = "unexpected end of file"; |
7b4ef1ae |
1124 | goto error; |
1125 | } |
6ca3d5c6 |
1126 | strip_crlf(line2); |
1127 | |
1128 | line2len = strlen(line2); |
1129 | line = sresize(line, len + line2len + 1, char); |
1130 | strcpy(line + len - 1, line2); |
1131 | len += line2len - 1; |
1132 | assert(!line[len]); |
1133 | |
dfb88efd |
1134 | smemclr(line2, strlen(line2)); |
6ca3d5c6 |
1135 | sfree(line2); |
1136 | line2 = NULL; |
7b4ef1ae |
1137 | } |
6ca3d5c6 |
1138 | p = line + hdrstart; |
1139 | strip_crlf(p); |
1140 | if (!strcmp(line, "Comment")) { |
7b4ef1ae |
1141 | /* Strip quotes in comment if present. */ |
1142 | if (p[0] == '"' && p[strlen(p)-1] == '"') { |
1143 | p++; |
1144 | p[strlen(p)-1] = '\0'; |
1145 | } |
1146 | strncpy(ret->comment, p, sizeof(ret->comment)); |
1147 | ret->comment[sizeof(ret->comment)-1] = '\0'; |
1148 | } |
1149 | } else { |
1150 | headers_done = 1; |
1151 | |
6ca3d5c6 |
1152 | p = line; |
7b4ef1ae |
1153 | while (isbase64(*p)) { |
1154 | base64_bit[base64_chars++] = *p; |
1155 | if (base64_chars == 4) { |
1156 | unsigned char out[3]; |
1157 | |
1158 | base64_chars = 0; |
1159 | |
1160 | len = base64_decode_atom(base64_bit, out); |
1161 | |
1162 | if (len <= 0) { |
1e87cce5 |
1163 | errmsg = "invalid base64 encoding"; |
7b4ef1ae |
1164 | goto error; |
1165 | } |
1166 | |
1167 | if (ret->keyblob_len + len > ret->keyblob_size) { |
1168 | ret->keyblob_size = ret->keyblob_len + len + 256; |
3d88e64d |
1169 | ret->keyblob = sresize(ret->keyblob, ret->keyblob_size, |
1170 | unsigned char); |
7b4ef1ae |
1171 | } |
1172 | |
1173 | memcpy(ret->keyblob + ret->keyblob_len, out, len); |
1174 | ret->keyblob_len += len; |
1175 | } |
1176 | |
1177 | p++; |
1178 | } |
1179 | } |
dfb88efd |
1180 | smemclr(line, strlen(line)); |
6ca3d5c6 |
1181 | sfree(line); |
1182 | line = NULL; |
7b4ef1ae |
1183 | } |
1184 | |
1185 | if (ret->keyblob_len == 0 || !ret->keyblob) { |
1e87cce5 |
1186 | errmsg = "key body not present"; |
7b4ef1ae |
1187 | goto error; |
1188 | } |
1189 | |
038ec85e |
1190 | fclose(fp); |
1e87cce5 |
1191 | if (errmsg_p) *errmsg_p = NULL; |
7b4ef1ae |
1192 | return ret; |
1193 | |
1194 | error: |
038ec85e |
1195 | if (fp) |
1196 | fclose(fp); |
1197 | |
6ca3d5c6 |
1198 | if (line) { |
dfb88efd |
1199 | smemclr(line, strlen(line)); |
6ca3d5c6 |
1200 | sfree(line); |
1201 | line = NULL; |
1202 | } |
7b4ef1ae |
1203 | if (ret) { |
ee5c1422 |
1204 | if (ret->keyblob) { |
dfb88efd |
1205 | smemclr(ret->keyblob, ret->keyblob_size); |
ee5c1422 |
1206 | sfree(ret->keyblob); |
1207 | } |
dfb88efd |
1208 | smemclr(ret, sizeof(*ret)); |
7b4ef1ae |
1209 | sfree(ret); |
1210 | } |
1e87cce5 |
1211 | if (errmsg_p) *errmsg_p = errmsg; |
7b4ef1ae |
1212 | return NULL; |
1213 | } |
1214 | |
9a30e26b |
1215 | int sshcom_encrypted(const Filename *filename, char **comment) |
7b4ef1ae |
1216 | { |
1e87cce5 |
1217 | struct sshcom_key *key = load_sshcom_key(filename, NULL); |
7b4ef1ae |
1218 | int pos, len, answer; |
1219 | |
038ec85e |
1220 | answer = 0; |
1221 | |
7b4ef1ae |
1222 | *comment = NULL; |
1223 | if (!key) |
038ec85e |
1224 | goto done; |
7b4ef1ae |
1225 | |
1226 | /* |
1227 | * Check magic number. |
1228 | */ |
038ec85e |
1229 | if (GET_32BIT(key->keyblob) != 0x3f6ff9eb) { |
1230 | goto done; /* key is invalid */ |
1231 | } |
7b4ef1ae |
1232 | |
1233 | /* |
1234 | * Find the cipher-type string. |
1235 | */ |
7b4ef1ae |
1236 | pos = 8; |
1237 | if (key->keyblob_len < pos+4) |
1238 | goto done; /* key is far too short */ |
b1650067 |
1239 | len = toint(GET_32BIT(key->keyblob + pos)); |
1240 | if (len < 0 || len > key->keyblob_len - pos - 4) |
7b4ef1ae |
1241 | goto done; /* key is far too short */ |
b1650067 |
1242 | pos += 4 + len; /* skip key type */ |
1243 | len = toint(GET_32BIT(key->keyblob + pos)); /* find cipher-type length */ |
1244 | if (len < 0 || len > key->keyblob_len - pos - 4) |
7b4ef1ae |
1245 | goto done; /* cipher type string is incomplete */ |
1246 | if (len != 4 || 0 != memcmp(key->keyblob + pos + 4, "none", 4)) |
1247 | answer = 1; |
1248 | |
1249 | done: |
c16e353e |
1250 | if (key) { |
1251 | *comment = dupstr(key->comment); |
1252 | smemclr(key->keyblob, key->keyblob_size); |
1253 | sfree(key->keyblob); |
1254 | smemclr(key, sizeof(*key)); |
1255 | sfree(key); |
1256 | } else { |
1257 | *comment = dupstr(""); |
1258 | } |
7b4ef1ae |
1259 | return answer; |
1260 | } |
1261 | |
d714d740 |
1262 | static int sshcom_read_mpint(void *data, int len, struct mpint_pos *ret) |
7b4ef1ae |
1263 | { |
b1650067 |
1264 | unsigned bits, bytes; |
7b4ef1ae |
1265 | unsigned char *d = (unsigned char *) data; |
1266 | |
1267 | if (len < 4) |
1268 | goto error; |
1269 | bits = GET_32BIT(d); |
1270 | |
1271 | bytes = (bits + 7) / 8; |
1272 | if (len < 4+bytes) |
1273 | goto error; |
1274 | |
1275 | ret->start = d + 4; |
1276 | ret->bytes = bytes; |
1277 | return bytes+4; |
1278 | |
1279 | error: |
1280 | ret->start = NULL; |
1281 | ret->bytes = -1; |
1282 | return len; /* ensure further calls fail as well */ |
1283 | } |
1284 | |
96d19bc9 |
1285 | static int sshcom_put_mpint(void *target, void *data, int len) |
1286 | { |
1287 | unsigned char *d = (unsigned char *)target; |
1288 | unsigned char *i = (unsigned char *)data; |
1289 | int bits = len * 8 - 1; |
1290 | |
1291 | while (bits > 0) { |
1292 | if (*i & (1 << (bits & 7))) |
1293 | break; |
1294 | if (!(bits-- & 7)) |
1295 | i++, len--; |
1296 | } |
1297 | |
1298 | PUT_32BIT(d, bits+1); |
1299 | memcpy(d+4, i, len); |
1300 | return len+4; |
1301 | } |
1302 | |
1e87cce5 |
1303 | struct ssh2_userkey *sshcom_read(const Filename *filename, char *passphrase, |
1304 | const char **errmsg_p) |
7b4ef1ae |
1305 | { |
1e87cce5 |
1306 | struct sshcom_key *key = load_sshcom_key(filename, errmsg_p); |
7b4ef1ae |
1307 | char *errmsg; |
1308 | int pos, len; |
1309 | const char prefix_rsa[] = "if-modn{sign{rsa"; |
1310 | const char prefix_dsa[] = "dl-modp{sign{dsa"; |
1311 | enum { RSA, DSA } type; |
1312 | int encrypted; |
1313 | char *ciphertext; |
1314 | int cipherlen; |
1315 | struct ssh2_userkey *ret = NULL, *retkey; |
1316 | const struct ssh_signkey *alg; |
1317 | unsigned char *blob = NULL; |
224f397a |
1318 | int blobsize = 0, publen, privlen; |
7b4ef1ae |
1319 | |
1320 | if (!key) |
1321 | return NULL; |
1322 | |
1323 | /* |
1324 | * Check magic number. |
1325 | */ |
96d19bc9 |
1326 | if (GET_32BIT(key->keyblob) != SSHCOM_MAGIC_NUMBER) { |
1e87cce5 |
1327 | errmsg = "key does not begin with magic number"; |
7b4ef1ae |
1328 | goto error; |
1329 | } |
1330 | |
1331 | /* |
1332 | * Determine the key type. |
1333 | */ |
1334 | pos = 8; |
1335 | if (key->keyblob_len < pos+4 || |
b1650067 |
1336 | (len = toint(GET_32BIT(key->keyblob + pos))) < 0 || |
1337 | len > key->keyblob_len - pos - 4) { |
1e87cce5 |
1338 | errmsg = "key blob does not contain a key type string"; |
7b4ef1ae |
1339 | goto error; |
1340 | } |
1341 | if (len > sizeof(prefix_rsa) - 1 && |
1342 | !memcmp(key->keyblob+pos+4, prefix_rsa, sizeof(prefix_rsa) - 1)) { |
1343 | type = RSA; |
1344 | } else if (len > sizeof(prefix_dsa) - 1 && |
1345 | !memcmp(key->keyblob+pos+4, prefix_dsa, sizeof(prefix_dsa) - 1)) { |
1346 | type = DSA; |
1347 | } else { |
1e87cce5 |
1348 | errmsg = "key is of unknown type"; |
7b4ef1ae |
1349 | goto error; |
1350 | } |
1351 | pos += 4+len; |
1352 | |
1353 | /* |
1354 | * Determine the cipher type. |
1355 | */ |
1356 | if (key->keyblob_len < pos+4 || |
b1650067 |
1357 | (len = toint(GET_32BIT(key->keyblob + pos))) < 0 || |
1358 | len > key->keyblob_len - pos - 4) { |
1e87cce5 |
1359 | errmsg = "key blob does not contain a cipher type string"; |
7b4ef1ae |
1360 | goto error; |
1361 | } |
1362 | if (len == 4 && !memcmp(key->keyblob+pos+4, "none", 4)) |
1363 | encrypted = 0; |
1364 | else if (len == 8 && !memcmp(key->keyblob+pos+4, "3des-cbc", 8)) |
1365 | encrypted = 1; |
1366 | else { |
1e87cce5 |
1367 | errmsg = "key encryption is of unknown type"; |
7b4ef1ae |
1368 | goto error; |
1369 | } |
1370 | pos += 4+len; |
1371 | |
1372 | /* |
1373 | * Get hold of the encrypted part of the key. |
1374 | */ |
1375 | if (key->keyblob_len < pos+4 || |
b1650067 |
1376 | (len = toint(GET_32BIT(key->keyblob + pos))) < 0 || |
1377 | len > key->keyblob_len - pos - 4) { |
1e87cce5 |
1378 | errmsg = "key blob does not contain actual key data"; |
7b4ef1ae |
1379 | goto error; |
1380 | } |
201188af |
1381 | ciphertext = (char *)key->keyblob + pos + 4; |
7b4ef1ae |
1382 | cipherlen = len; |
1383 | if (cipherlen == 0) { |
1e87cce5 |
1384 | errmsg = "length of key data is zero"; |
7b4ef1ae |
1385 | goto error; |
1386 | } |
1387 | |
1388 | /* |
1389 | * Decrypt it if necessary. |
1390 | */ |
1391 | if (encrypted) { |
1392 | /* |
1393 | * Derive encryption key from passphrase and iv/salt: |
1394 | * |
1395 | * - let block A equal MD5(passphrase) |
1396 | * - let block B equal MD5(passphrase || A) |
1397 | * - block C would be MD5(passphrase || A || B) and so on |
1398 | * - encryption key is the first N bytes of A || B |
1399 | */ |
1400 | struct MD5Context md5c; |
1401 | unsigned char keybuf[32], iv[8]; |
1402 | |
1403 | if (cipherlen % 8 != 0) { |
1e87cce5 |
1404 | errmsg = "encrypted part of key is not a multiple of cipher block" |
7b4ef1ae |
1405 | " size"; |
1406 | goto error; |
1407 | } |
1408 | |
1409 | MD5Init(&md5c); |
201188af |
1410 | MD5Update(&md5c, (unsigned char *)passphrase, strlen(passphrase)); |
7b4ef1ae |
1411 | MD5Final(keybuf, &md5c); |
1412 | |
1413 | MD5Init(&md5c); |
201188af |
1414 | MD5Update(&md5c, (unsigned char *)passphrase, strlen(passphrase)); |
7b4ef1ae |
1415 | MD5Update(&md5c, keybuf, 16); |
1416 | MD5Final(keybuf+16, &md5c); |
1417 | |
1418 | /* |
1419 | * Now decrypt the key blob. |
1420 | */ |
ee5c1422 |
1421 | memset(iv, 0, sizeof(iv)); |
201188af |
1422 | des3_decrypt_pubkey_ossh(keybuf, iv, (unsigned char *)ciphertext, |
1423 | cipherlen); |
7b4ef1ae |
1424 | |
dfb88efd |
1425 | smemclr(&md5c, sizeof(md5c)); |
1426 | smemclr(keybuf, sizeof(keybuf)); |
ee5c1422 |
1427 | |
7b4ef1ae |
1428 | /* |
1429 | * Hereafter we return WRONG_PASSPHRASE for any parsing |
ee5c1422 |
1430 | * error. (But only if we've just tried to decrypt it! |
1431 | * Returning WRONG_PASSPHRASE for an unencrypted key is |
1432 | * automatic doom.) |
7b4ef1ae |
1433 | */ |
1434 | if (encrypted) |
1435 | ret = SSH2_WRONG_PASSPHRASE; |
1436 | } |
1437 | |
1438 | /* |
1439 | * Strip away the containing string to get to the real meat. |
1440 | */ |
b1650067 |
1441 | len = toint(GET_32BIT(ciphertext)); |
1bb20a38 |
1442 | if (len < 0 || len > cipherlen-4) { |
7b4ef1ae |
1443 | errmsg = "containing string was ill-formed"; |
1444 | goto error; |
1445 | } |
1446 | ciphertext += 4; |
1447 | cipherlen = len; |
1448 | |
1449 | /* |
1450 | * Now we break down into RSA versus DSA. In either case we'll |
1451 | * construct public and private blobs in our own format, and |
1452 | * end up feeding them to alg->createkey(). |
1453 | */ |
ee5c1422 |
1454 | blobsize = cipherlen + 256; |
3d88e64d |
1455 | blob = snewn(blobsize, unsigned char); |
7b4ef1ae |
1456 | privlen = 0; |
1457 | if (type == RSA) { |
1458 | struct mpint_pos n, e, d, u, p, q; |
1459 | int pos = 0; |
1460 | pos += sshcom_read_mpint(ciphertext+pos, cipherlen-pos, &e); |
1461 | pos += sshcom_read_mpint(ciphertext+pos, cipherlen-pos, &d); |
1462 | pos += sshcom_read_mpint(ciphertext+pos, cipherlen-pos, &n); |
1463 | pos += sshcom_read_mpint(ciphertext+pos, cipherlen-pos, &u); |
1464 | pos += sshcom_read_mpint(ciphertext+pos, cipherlen-pos, &p); |
1465 | pos += sshcom_read_mpint(ciphertext+pos, cipherlen-pos, &q); |
1466 | if (!q.start) { |
1467 | errmsg = "key data did not contain six integers"; |
1468 | goto error; |
1469 | } |
1470 | |
1471 | alg = &ssh_rsa; |
1472 | pos = 0; |
1473 | pos += put_string(blob+pos, "ssh-rsa", 7); |
1474 | pos += put_mp(blob+pos, e.start, e.bytes); |
1475 | pos += put_mp(blob+pos, n.start, n.bytes); |
1476 | publen = pos; |
1477 | pos += put_string(blob+pos, d.start, d.bytes); |
1478 | pos += put_mp(blob+pos, q.start, q.bytes); |
1479 | pos += put_mp(blob+pos, p.start, p.bytes); |
1480 | pos += put_mp(blob+pos, u.start, u.bytes); |
1481 | privlen = pos - publen; |
a607fe54 |
1482 | } else { |
7b4ef1ae |
1483 | struct mpint_pos p, q, g, x, y; |
1484 | int pos = 4; |
9dfa2ea8 |
1485 | |
1486 | assert(type == DSA); /* the only other option from the if above */ |
1487 | |
7b4ef1ae |
1488 | if (GET_32BIT(ciphertext) != 0) { |
1489 | errmsg = "predefined DSA parameters not supported"; |
1490 | goto error; |
1491 | } |
1492 | pos += sshcom_read_mpint(ciphertext+pos, cipherlen-pos, &p); |
1493 | pos += sshcom_read_mpint(ciphertext+pos, cipherlen-pos, &g); |
1494 | pos += sshcom_read_mpint(ciphertext+pos, cipherlen-pos, &q); |
1495 | pos += sshcom_read_mpint(ciphertext+pos, cipherlen-pos, &y); |
1496 | pos += sshcom_read_mpint(ciphertext+pos, cipherlen-pos, &x); |
1497 | if (!x.start) { |
1498 | errmsg = "key data did not contain five integers"; |
1499 | goto error; |
1500 | } |
1501 | |
1502 | alg = &ssh_dss; |
1503 | pos = 0; |
1504 | pos += put_string(blob+pos, "ssh-dss", 7); |
1505 | pos += put_mp(blob+pos, p.start, p.bytes); |
1506 | pos += put_mp(blob+pos, q.start, q.bytes); |
1507 | pos += put_mp(blob+pos, g.start, g.bytes); |
1508 | pos += put_mp(blob+pos, y.start, y.bytes); |
1509 | publen = pos; |
1510 | pos += put_mp(blob+pos, x.start, x.bytes); |
1511 | privlen = pos - publen; |
a607fe54 |
1512 | } |
7b4ef1ae |
1513 | |
1514 | assert(privlen > 0); /* should have bombed by now if not */ |
1515 | |
3d88e64d |
1516 | retkey = snew(struct ssh2_userkey); |
7b4ef1ae |
1517 | retkey->alg = alg; |
1518 | retkey->data = alg->createkey(blob, publen, blob+publen, privlen); |
1519 | if (!retkey->data) { |
1520 | sfree(retkey); |
1521 | errmsg = "unable to create key data structure"; |
1522 | goto error; |
1523 | } |
1524 | retkey->comment = dupstr(key->comment); |
1525 | |
1526 | errmsg = NULL; /* no error */ |
1527 | ret = retkey; |
1528 | |
1529 | error: |
ee5c1422 |
1530 | if (blob) { |
dfb88efd |
1531 | smemclr(blob, blobsize); |
ee5c1422 |
1532 | sfree(blob); |
1533 | } |
dfb88efd |
1534 | smemclr(key->keyblob, key->keyblob_size); |
7b4ef1ae |
1535 | sfree(key->keyblob); |
dfb88efd |
1536 | smemclr(key, sizeof(*key)); |
7b4ef1ae |
1537 | sfree(key); |
1e87cce5 |
1538 | if (errmsg_p) *errmsg_p = errmsg; |
7b4ef1ae |
1539 | return ret; |
1540 | } |
96d19bc9 |
1541 | |
9a30e26b |
1542 | int sshcom_write(const Filename *filename, struct ssh2_userkey *key, |
1543 | char *passphrase) |
96d19bc9 |
1544 | { |
1545 | unsigned char *pubblob, *privblob; |
1546 | int publen, privlen; |
1547 | unsigned char *outblob; |
1548 | int outlen; |
1549 | struct mpint_pos numbers[6]; |
1550 | int nnumbers, initial_zero, pos, lenpos, i; |
1551 | char *type; |
1552 | char *ciphertext; |
1553 | int cipherlen; |
1554 | int ret = 0; |
1555 | FILE *fp; |
1556 | |
1557 | /* |
1558 | * Fetch the key blobs. |
1559 | */ |
1560 | pubblob = key->alg->public_blob(key->data, &publen); |
1561 | privblob = key->alg->private_blob(key->data, &privlen); |
1562 | outblob = NULL; |
1563 | |
1564 | /* |
1565 | * Find the sequence of integers to be encoded into the OpenSSH |
1566 | * key blob, and also decide on the header line. |
1567 | */ |
1568 | if (key->alg == &ssh_rsa) { |
1569 | int pos; |
1570 | struct mpint_pos n, e, d, p, q, iqmp; |
1571 | |
b1650067 |
1572 | /* |
1573 | * These blobs were generated from inside PuTTY, so we needn't |
1574 | * treat them as untrusted. |
1575 | */ |
96d19bc9 |
1576 | pos = 4 + GET_32BIT(pubblob); |
1577 | pos += ssh2_read_mpint(pubblob+pos, publen-pos, &e); |
1578 | pos += ssh2_read_mpint(pubblob+pos, publen-pos, &n); |
1579 | pos = 0; |
1580 | pos += ssh2_read_mpint(privblob+pos, privlen-pos, &d); |
1581 | pos += ssh2_read_mpint(privblob+pos, privlen-pos, &p); |
1582 | pos += ssh2_read_mpint(privblob+pos, privlen-pos, &q); |
1583 | pos += ssh2_read_mpint(privblob+pos, privlen-pos, &iqmp); |
1584 | |
1585 | assert(e.start && iqmp.start); /* can't go wrong */ |
1586 | |
1587 | numbers[0] = e; |
1588 | numbers[1] = d; |
1589 | numbers[2] = n; |
1590 | numbers[3] = iqmp; |
1591 | numbers[4] = q; |
1592 | numbers[5] = p; |
1593 | |
1594 | nnumbers = 6; |
1595 | initial_zero = 0; |
1596 | type = "if-modn{sign{rsa-pkcs1-sha1},encrypt{rsa-pkcs1v2-oaep}}"; |
1597 | } else if (key->alg == &ssh_dss) { |
1598 | int pos; |
1599 | struct mpint_pos p, q, g, y, x; |
1600 | |
b1650067 |
1601 | /* |
1602 | * These blobs were generated from inside PuTTY, so we needn't |
1603 | * treat them as untrusted. |
1604 | */ |
96d19bc9 |
1605 | pos = 4 + GET_32BIT(pubblob); |
1606 | pos += ssh2_read_mpint(pubblob+pos, publen-pos, &p); |
1607 | pos += ssh2_read_mpint(pubblob+pos, publen-pos, &q); |
1608 | pos += ssh2_read_mpint(pubblob+pos, publen-pos, &g); |
1609 | pos += ssh2_read_mpint(pubblob+pos, publen-pos, &y); |
1610 | pos = 0; |
1611 | pos += ssh2_read_mpint(privblob+pos, privlen-pos, &x); |
1612 | |
1613 | assert(y.start && x.start); /* can't go wrong */ |
1614 | |
1615 | numbers[0] = p; |
1616 | numbers[1] = g; |
1617 | numbers[2] = q; |
1618 | numbers[3] = y; |
1619 | numbers[4] = x; |
1620 | |
1621 | nnumbers = 5; |
1622 | initial_zero = 1; |
1623 | type = "dl-modp{sign{dsa-nist-sha1},dh{plain}}"; |
1624 | } else { |
1625 | assert(0); /* zoinks! */ |
8815b68b |
1626 | exit(1); /* XXX: GCC doesn't understand assert() on some systems. */ |
96d19bc9 |
1627 | } |
1628 | |
1629 | /* |
1630 | * Total size of key blob will be somewhere under 512 plus |
1631 | * combined length of integers. We'll calculate the more |
1632 | * precise size as we construct the blob. |
1633 | */ |
1634 | outlen = 512; |
1635 | for (i = 0; i < nnumbers; i++) |
1636 | outlen += 4 + numbers[i].bytes; |
3d88e64d |
1637 | outblob = snewn(outlen, unsigned char); |
96d19bc9 |
1638 | |
1639 | /* |
1640 | * Create the unencrypted key blob. |
1641 | */ |
1642 | pos = 0; |
1643 | PUT_32BIT(outblob+pos, SSHCOM_MAGIC_NUMBER); pos += 4; |
1644 | pos += 4; /* length field, fill in later */ |
1645 | pos += put_string(outblob+pos, type, strlen(type)); |
1646 | { |
1647 | char *ciphertype = passphrase ? "3des-cbc" : "none"; |
1648 | pos += put_string(outblob+pos, ciphertype, strlen(ciphertype)); |
1649 | } |
1650 | lenpos = pos; /* remember this position */ |
1651 | pos += 4; /* encrypted-blob size */ |
1652 | pos += 4; /* encrypted-payload size */ |
1653 | if (initial_zero) { |
1654 | PUT_32BIT(outblob+pos, 0); |
1655 | pos += 4; |
1656 | } |
1657 | for (i = 0; i < nnumbers; i++) |
1658 | pos += sshcom_put_mpint(outblob+pos, |
1659 | numbers[i].start, numbers[i].bytes); |
1660 | /* Now wrap up the encrypted payload. */ |
1661 | PUT_32BIT(outblob+lenpos+4, pos - (lenpos+8)); |
1662 | /* Pad encrypted blob to a multiple of cipher block size. */ |
1663 | if (passphrase) { |
1664 | int padding = -(pos - (lenpos+4)) & 7; |
1665 | while (padding--) |
1666 | outblob[pos++] = random_byte(); |
1667 | } |
201188af |
1668 | ciphertext = (char *)outblob+lenpos+4; |
96d19bc9 |
1669 | cipherlen = pos - (lenpos+4); |
1670 | assert(!passphrase || cipherlen % 8 == 0); |
1671 | /* Wrap up the encrypted blob string. */ |
1672 | PUT_32BIT(outblob+lenpos, cipherlen); |
1673 | /* And finally fill in the total length field. */ |
1674 | PUT_32BIT(outblob+4, pos); |
1675 | |
1676 | assert(pos < outlen); |
1677 | |
1678 | /* |
1679 | * Encrypt the key. |
1680 | */ |
1681 | if (passphrase) { |
1682 | /* |
1683 | * Derive encryption key from passphrase and iv/salt: |
1684 | * |
1685 | * - let block A equal MD5(passphrase) |
1686 | * - let block B equal MD5(passphrase || A) |
1687 | * - block C would be MD5(passphrase || A || B) and so on |
1688 | * - encryption key is the first N bytes of A || B |
1689 | */ |
1690 | struct MD5Context md5c; |
1691 | unsigned char keybuf[32], iv[8]; |
1692 | |
1693 | MD5Init(&md5c); |
201188af |
1694 | MD5Update(&md5c, (unsigned char *)passphrase, strlen(passphrase)); |
96d19bc9 |
1695 | MD5Final(keybuf, &md5c); |
1696 | |
1697 | MD5Init(&md5c); |
201188af |
1698 | MD5Update(&md5c, (unsigned char *)passphrase, strlen(passphrase)); |
96d19bc9 |
1699 | MD5Update(&md5c, keybuf, 16); |
1700 | MD5Final(keybuf+16, &md5c); |
1701 | |
1702 | /* |
1703 | * Now decrypt the key blob. |
1704 | */ |
1705 | memset(iv, 0, sizeof(iv)); |
201188af |
1706 | des3_encrypt_pubkey_ossh(keybuf, iv, (unsigned char *)ciphertext, |
1707 | cipherlen); |
96d19bc9 |
1708 | |
dfb88efd |
1709 | smemclr(&md5c, sizeof(md5c)); |
1710 | smemclr(keybuf, sizeof(keybuf)); |
96d19bc9 |
1711 | } |
1712 | |
1713 | /* |
1714 | * And save it. We'll use Unix line endings just in case it's |
1715 | * subsequently transferred in binary mode. |
1716 | */ |
962468d4 |
1717 | fp = f_open(filename, "wb", TRUE); /* ensure Unix line endings */ |
96d19bc9 |
1718 | if (!fp) |
1719 | goto error; |
1720 | fputs("---- BEGIN SSH2 ENCRYPTED PRIVATE KEY ----\n", fp); |
1721 | fprintf(fp, "Comment: \""); |
1722 | /* |
1723 | * Comment header is broken with backslash-newline if it goes |
1724 | * over 70 chars. Although it's surrounded by quotes, it |
1725 | * _doesn't_ escape backslashes or quotes within the string. |
1726 | * Don't ask me, I didn't design it. |
1727 | */ |
1728 | { |
1729 | int slen = 60; /* starts at 60 due to "Comment: " */ |
1730 | char *c = key->comment; |
6ef15436 |
1731 | while ((int)strlen(c) > slen) { |
96d19bc9 |
1732 | fprintf(fp, "%.*s\\\n", slen, c); |
1733 | c += slen; |
1734 | slen = 70; /* allow 70 chars on subsequent lines */ |
1735 | } |
1736 | fprintf(fp, "%s\"\n", c); |
1737 | } |
1738 | base64_encode(fp, outblob, pos, 70); |
1739 | fputs("---- END SSH2 ENCRYPTED PRIVATE KEY ----\n", fp); |
1740 | fclose(fp); |
1741 | ret = 1; |
1742 | |
1743 | error: |
1744 | if (outblob) { |
dfb88efd |
1745 | smemclr(outblob, outlen); |
96d19bc9 |
1746 | sfree(outblob); |
1747 | } |
1748 | if (privblob) { |
dfb88efd |
1749 | smemclr(privblob, privlen); |
96d19bc9 |
1750 | sfree(privblob); |
1751 | } |
1752 | if (pubblob) { |
dfb88efd |
1753 | smemclr(pubblob, publen); |
96d19bc9 |
1754 | sfree(pubblob); |
1755 | } |
1756 | return ret; |
1757 | } |