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