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 | |
9dda6459 |
112 | /* ---------------------------------------------------------------------- |
113 | * Helper routines. (The base64 ones are defined in sshpubk.c.) |
114 | */ |
115 | |
116 | #define isbase64(c) ( ((c) >= 'A' && (c) <= 'Z') || \ |
117 | ((c) >= 'a' && (c) <= 'z') || \ |
118 | ((c) >= '0' && (c) <= '9') || \ |
119 | (c) == '+' || (c) == '/' || (c) == '=' \ |
120 | ) |
121 | |
9dda6459 |
122 | /* |
123 | * Read an ASN.1/BER identifier and length pair. |
124 | * |
125 | * Flags are a combination of the #defines listed below. |
126 | * |
127 | * Returns -1 if unsuccessful; otherwise returns the number of |
128 | * bytes used out of the source data. |
129 | */ |
130 | |
131 | /* ASN.1 tag classes. */ |
132 | #define ASN1_CLASS_UNIVERSAL (0 << 6) |
133 | #define ASN1_CLASS_APPLICATION (1 << 6) |
134 | #define ASN1_CLASS_CONTEXT_SPECIFIC (2 << 6) |
135 | #define ASN1_CLASS_PRIVATE (3 << 6) |
136 | #define ASN1_CLASS_MASK (3 << 6) |
137 | |
138 | /* Primitive versus constructed bit. */ |
139 | #define ASN1_CONSTRUCTED (1 << 5) |
140 | |
d714d740 |
141 | static int ber_read_id_len(void *source, int sourcelen, |
142 | int *id, int *length, int *flags) |
9dda6459 |
143 | { |
144 | unsigned char *p = (unsigned char *) source; |
145 | |
146 | if (sourcelen == 0) |
147 | return -1; |
148 | |
149 | *flags = (*p & 0xE0); |
150 | if ((*p & 0x1F) == 0x1F) { |
151 | *id = 0; |
152 | while (*p & 0x80) { |
9dda6459 |
153 | p++, sourcelen--; |
154 | if (sourcelen == 0) |
155 | return -1; |
3a5a5a59 |
156 | *id = (*id << 7) | (*p & 0x7F); |
9dda6459 |
157 | } |
9dda6459 |
158 | p++, sourcelen--; |
159 | } else { |
160 | *id = *p & 0x1F; |
161 | p++, sourcelen--; |
162 | } |
163 | |
164 | if (sourcelen == 0) |
165 | return -1; |
166 | |
167 | if (*p & 0x80) { |
168 | int n = *p & 0x7F; |
169 | p++, sourcelen--; |
170 | if (sourcelen < n) |
171 | return -1; |
172 | *length = 0; |
173 | while (n--) |
174 | *length = (*length << 8) | (*p++); |
175 | sourcelen -= n; |
176 | } else { |
177 | *length = *p; |
178 | p++, sourcelen--; |
179 | } |
180 | |
181 | return p - (unsigned char *) source; |
182 | } |
183 | |
d23a9b21 |
184 | /* |
185 | * Write an ASN.1/BER identifier and length pair. Returns the |
186 | * number of bytes consumed. Assumes dest contains enough space. |
187 | * Will avoid writing anything if dest is NULL, but still return |
188 | * amount of space required. |
189 | */ |
d714d740 |
190 | static int ber_write_id_len(void *dest, int id, int length, int flags) |
d23a9b21 |
191 | { |
192 | unsigned char *d = (unsigned char *)dest; |
193 | int len = 0; |
194 | |
195 | if (id <= 30) { |
196 | /* |
197 | * Identifier is one byte. |
198 | */ |
199 | len++; |
200 | if (d) *d++ = id | flags; |
201 | } else { |
202 | int n; |
203 | /* |
204 | * Identifier is multiple bytes: the first byte is 11111 |
205 | * plus the flags, and subsequent bytes encode the value of |
206 | * the identifier, 7 bits at a time, with the top bit of |
207 | * each byte 1 except the last one which is 0. |
208 | */ |
209 | len++; |
210 | if (d) *d++ = 0x1F | flags; |
211 | for (n = 1; (id >> (7*n)) > 0; n++) |
212 | continue; /* count the bytes */ |
213 | while (n--) { |
214 | len++; |
215 | if (d) *d++ = (n ? 0x80 : 0) | ((id >> (7*n)) & 0x7F); |
216 | } |
217 | } |
218 | |
219 | if (length < 128) { |
220 | /* |
221 | * Length is one byte. |
222 | */ |
223 | len++; |
224 | if (d) *d++ = length; |
225 | } else { |
226 | int n; |
227 | /* |
228 | * Length is multiple bytes. The first is 0x80 plus the |
229 | * number of subsequent bytes, and the subsequent bytes |
230 | * encode the actual length. |
231 | */ |
232 | for (n = 1; (length >> (8*n)) > 0; n++) |
233 | continue; /* count the bytes */ |
234 | len++; |
235 | if (d) *d++ = 0x80 | n; |
236 | while (n--) { |
237 | len++; |
238 | if (d) *d++ = (length >> (8*n)) & 0xFF; |
239 | } |
240 | } |
241 | |
242 | return len; |
243 | } |
244 | |
7b4ef1ae |
245 | static int put_string(void *target, void *data, int len) |
246 | { |
247 | unsigned char *d = (unsigned char *)target; |
248 | |
249 | PUT_32BIT(d, len); |
250 | memcpy(d+4, data, len); |
251 | return len+4; |
252 | } |
253 | |
254 | static int put_mp(void *target, void *data, int len) |
255 | { |
256 | unsigned char *d = (unsigned char *)target; |
257 | unsigned char *i = (unsigned char *)data; |
258 | |
259 | if (*i & 0x80) { |
260 | PUT_32BIT(d, len+1); |
261 | d[4] = 0; |
262 | memcpy(d+5, data, len); |
263 | return len+5; |
264 | } else { |
265 | PUT_32BIT(d, len); |
266 | memcpy(d+4, data, len); |
267 | return len+4; |
268 | } |
269 | } |
270 | |
d23a9b21 |
271 | /* Simple structure to point to an mp-int within a blob. */ |
272 | struct mpint_pos { void *start; int bytes; }; |
273 | |
d714d740 |
274 | static int ssh2_read_mpint(void *data, int len, struct mpint_pos *ret) |
d23a9b21 |
275 | { |
276 | int bytes; |
277 | unsigned char *d = (unsigned char *) data; |
278 | |
279 | if (len < 4) |
280 | goto error; |
281 | bytes = GET_32BIT(d); |
282 | if (len < 4+bytes) |
283 | goto error; |
284 | |
285 | ret->start = d + 4; |
286 | ret->bytes = bytes; |
287 | return bytes+4; |
288 | |
289 | error: |
290 | ret->start = NULL; |
291 | ret->bytes = -1; |
292 | return len; /* ensure further calls fail as well */ |
293 | } |
294 | |
9dda6459 |
295 | /* ---------------------------------------------------------------------- |
d23a9b21 |
296 | * Code to read and write OpenSSH private keys. |
9dda6459 |
297 | */ |
298 | |
299 | enum { OSSH_DSA, OSSH_RSA }; |
300 | struct openssh_key { |
301 | int type; |
302 | int encrypted; |
303 | char iv[32]; |
304 | unsigned char *keyblob; |
305 | int keyblob_len, keyblob_size; |
306 | }; |
307 | |
1e87cce5 |
308 | static struct openssh_key *load_openssh_key(const Filename *filename, |
309 | const char **errmsg_p) |
9dda6459 |
310 | { |
311 | struct openssh_key *ret; |
312 | FILE *fp; |
313 | char buffer[256]; |
314 | char *errmsg, *p; |
315 | int headers_done; |
ee5c1422 |
316 | char base64_bit[4]; |
317 | int base64_chars = 0; |
9dda6459 |
318 | |
3d88e64d |
319 | ret = snew(struct openssh_key); |
9dda6459 |
320 | ret->keyblob = NULL; |
321 | ret->keyblob_len = ret->keyblob_size = 0; |
322 | ret->encrypted = 0; |
323 | memset(ret->iv, 0, sizeof(ret->iv)); |
324 | |
9a30e26b |
325 | fp = f_open(*filename, "r"); |
9dda6459 |
326 | if (!fp) { |
1e87cce5 |
327 | errmsg = "unable to open key file"; |
9dda6459 |
328 | goto error; |
329 | } |
330 | if (!fgets(buffer, sizeof(buffer), fp) || |
331 | 0 != strncmp(buffer, "-----BEGIN ", 11) || |
332 | 0 != strcmp(buffer+strlen(buffer)-17, "PRIVATE KEY-----\n")) { |
1e87cce5 |
333 | errmsg = "file does not begin with OpenSSH key header"; |
9dda6459 |
334 | goto error; |
335 | } |
336 | if (!strcmp(buffer, "-----BEGIN RSA PRIVATE KEY-----\n")) |
337 | ret->type = OSSH_RSA; |
338 | else if (!strcmp(buffer, "-----BEGIN DSA PRIVATE KEY-----\n")) |
339 | ret->type = OSSH_DSA; |
340 | else { |
1e87cce5 |
341 | errmsg = "unrecognised key type"; |
9dda6459 |
342 | goto error; |
343 | } |
344 | |
345 | headers_done = 0; |
346 | while (1) { |
347 | if (!fgets(buffer, sizeof(buffer), fp)) { |
1e87cce5 |
348 | errmsg = "unexpected end of file"; |
9dda6459 |
349 | goto error; |
350 | } |
351 | if (0 == strncmp(buffer, "-----END ", 9) && |
352 | 0 == strcmp(buffer+strlen(buffer)-17, "PRIVATE KEY-----\n")) |
353 | break; /* done */ |
354 | if ((p = strchr(buffer, ':')) != NULL) { |
355 | if (headers_done) { |
1e87cce5 |
356 | errmsg = "header found in body of key data"; |
9dda6459 |
357 | goto error; |
358 | } |
359 | *p++ = '\0'; |
360 | while (*p && isspace((unsigned char)*p)) p++; |
361 | if (!strcmp(buffer, "Proc-Type")) { |
362 | if (p[0] != '4' || p[1] != ',') { |
363 | errmsg = "Proc-Type is not 4 (only 4 is supported)"; |
364 | goto error; |
365 | } |
366 | p += 2; |
367 | if (!strcmp(p, "ENCRYPTED\n")) |
368 | ret->encrypted = 1; |
369 | } else if (!strcmp(buffer, "DEK-Info")) { |
370 | int i, j; |
371 | |
372 | if (strncmp(p, "DES-EDE3-CBC,", 13)) { |
1e87cce5 |
373 | errmsg = "ciphers other than DES-EDE3-CBC not supported"; |
9dda6459 |
374 | goto error; |
375 | } |
376 | p += 13; |
377 | for (i = 0; i < 8; i++) { |
378 | if (1 != sscanf(p, "%2x", &j)) |
379 | break; |
380 | ret->iv[i] = j; |
381 | p += 2; |
382 | } |
383 | if (i < 8) { |
1e87cce5 |
384 | errmsg = "expected 16-digit iv in DEK-Info"; |
9dda6459 |
385 | goto error; |
386 | } |
387 | } |
388 | } else { |
389 | headers_done = 1; |
390 | |
391 | p = buffer; |
ee5c1422 |
392 | while (isbase64(*p)) { |
393 | base64_bit[base64_chars++] = *p; |
394 | if (base64_chars == 4) { |
395 | unsigned char out[3]; |
396 | int len; |
9dda6459 |
397 | |
ee5c1422 |
398 | base64_chars = 0; |
9dda6459 |
399 | |
ee5c1422 |
400 | len = base64_decode_atom(base64_bit, out); |
9dda6459 |
401 | |
ee5c1422 |
402 | if (len <= 0) { |
1e87cce5 |
403 | errmsg = "invalid base64 encoding"; |
ee5c1422 |
404 | goto error; |
405 | } |
406 | |
407 | if (ret->keyblob_len + len > ret->keyblob_size) { |
408 | ret->keyblob_size = ret->keyblob_len + len + 256; |
3d88e64d |
409 | ret->keyblob = sresize(ret->keyblob, ret->keyblob_size, |
410 | unsigned char); |
ee5c1422 |
411 | } |
9dda6459 |
412 | |
ee5c1422 |
413 | memcpy(ret->keyblob + ret->keyblob_len, out, len); |
414 | ret->keyblob_len += len; |
9dda6459 |
415 | |
ee5c1422 |
416 | memset(out, 0, sizeof(out)); |
417 | } |
9dda6459 |
418 | |
ee5c1422 |
419 | p++; |
9dda6459 |
420 | } |
421 | } |
422 | } |
423 | |
424 | if (ret->keyblob_len == 0 || !ret->keyblob) { |
1e87cce5 |
425 | errmsg = "key body not present"; |
9dda6459 |
426 | goto error; |
427 | } |
428 | |
429 | if (ret->encrypted && ret->keyblob_len % 8 != 0) { |
1e87cce5 |
430 | errmsg = "encrypted key blob is not a multiple of cipher block size"; |
9dda6459 |
431 | goto error; |
432 | } |
433 | |
ee5c1422 |
434 | memset(buffer, 0, sizeof(buffer)); |
435 | memset(base64_bit, 0, sizeof(base64_bit)); |
1e87cce5 |
436 | if (errmsg_p) *errmsg_p = NULL; |
9dda6459 |
437 | return ret; |
438 | |
439 | error: |
ee5c1422 |
440 | memset(buffer, 0, sizeof(buffer)); |
441 | memset(base64_bit, 0, sizeof(base64_bit)); |
9dda6459 |
442 | if (ret) { |
ee5c1422 |
443 | if (ret->keyblob) { |
444 | memset(ret->keyblob, 0, ret->keyblob_size); |
445 | sfree(ret->keyblob); |
446 | } |
fb8344c9 |
447 | memset(ret, 0, sizeof(*ret)); |
9dda6459 |
448 | sfree(ret); |
449 | } |
1e87cce5 |
450 | if (errmsg_p) *errmsg_p = errmsg; |
9dda6459 |
451 | return NULL; |
452 | } |
453 | |
9a30e26b |
454 | int openssh_encrypted(const Filename *filename) |
9dda6459 |
455 | { |
1e87cce5 |
456 | struct openssh_key *key = load_openssh_key(filename, NULL); |
9dda6459 |
457 | int ret; |
458 | |
459 | if (!key) |
460 | return 0; |
461 | ret = key->encrypted; |
ee5c1422 |
462 | memset(key->keyblob, 0, key->keyblob_size); |
9dda6459 |
463 | sfree(key->keyblob); |
fb8344c9 |
464 | memset(key, 0, sizeof(*key)); |
9dda6459 |
465 | sfree(key); |
466 | return ret; |
467 | } |
468 | |
1e87cce5 |
469 | struct ssh2_userkey *openssh_read(const Filename *filename, char *passphrase, |
470 | const char **errmsg_p) |
9dda6459 |
471 | { |
1e87cce5 |
472 | struct openssh_key *key = load_openssh_key(filename, errmsg_p); |
9dda6459 |
473 | struct ssh2_userkey *retkey; |
474 | unsigned char *p; |
475 | int ret, id, len, flags; |
476 | int i, num_integers; |
477 | struct ssh2_userkey *retval = NULL; |
478 | char *errmsg; |
479 | unsigned char *blob; |
224f397a |
480 | int blobsize = 0, blobptr, privptr; |
481 | char *modptr = NULL; |
482 | int modlen = 0; |
9dda6459 |
483 | |
e3498db5 |
484 | blob = NULL; |
485 | |
9dda6459 |
486 | if (!key) |
487 | return NULL; |
488 | |
489 | if (key->encrypted) { |
490 | /* |
491 | * Derive encryption key from passphrase and iv/salt: |
492 | * |
493 | * - let block A equal MD5(passphrase || iv) |
494 | * - let block B equal MD5(A || passphrase || iv) |
495 | * - block C would be MD5(B || passphrase || iv) and so on |
496 | * - encryption key is the first N bytes of A || B |
497 | */ |
498 | struct MD5Context md5c; |
499 | unsigned char keybuf[32]; |
500 | |
501 | MD5Init(&md5c); |
201188af |
502 | MD5Update(&md5c, (unsigned char *)passphrase, strlen(passphrase)); |
503 | MD5Update(&md5c, (unsigned char *)key->iv, 8); |
9dda6459 |
504 | MD5Final(keybuf, &md5c); |
505 | |
506 | MD5Init(&md5c); |
507 | MD5Update(&md5c, keybuf, 16); |
201188af |
508 | MD5Update(&md5c, (unsigned char *)passphrase, strlen(passphrase)); |
509 | MD5Update(&md5c, (unsigned char *)key->iv, 8); |
9dda6459 |
510 | MD5Final(keybuf+16, &md5c); |
511 | |
512 | /* |
513 | * Now decrypt the key blob. |
514 | */ |
201188af |
515 | des3_decrypt_pubkey_ossh(keybuf, (unsigned char *)key->iv, |
9dda6459 |
516 | key->keyblob, key->keyblob_len); |
ee5c1422 |
517 | |
518 | memset(&md5c, 0, sizeof(md5c)); |
519 | memset(keybuf, 0, sizeof(keybuf)); |
9dda6459 |
520 | } |
521 | |
522 | /* |
523 | * Now we have a decrypted key blob, which contains an ASN.1 |
524 | * encoded private key. We must now untangle the ASN.1. |
525 | * |
526 | * We expect the whole key blob to be formatted as a SEQUENCE |
527 | * (0x30 followed by a length code indicating that the rest of |
528 | * the blob is part of the sequence). Within that SEQUENCE we |
529 | * expect to see a bunch of INTEGERs. What those integers mean |
530 | * depends on the key type: |
531 | * |
532 | * - For RSA, we expect the integers to be 0, n, e, d, p, q, |
533 | * dmp1, dmq1, iqmp in that order. (The last three are d mod |
534 | * (p-1), d mod (q-1), inverse of q mod p respectively.) |
535 | * |
536 | * - For DSA, we expect them to be 0, p, q, g, y, x in that |
537 | * order. |
538 | */ |
539 | |
540 | p = key->keyblob; |
541 | |
542 | /* Expect the SEQUENCE header. Take its absence as a failure to decrypt. */ |
543 | ret = ber_read_id_len(p, key->keyblob_len, &id, &len, &flags); |
544 | p += ret; |
545 | if (ret < 0 || id != 16) { |
546 | errmsg = "ASN.1 decoding failure"; |
547 | retval = SSH2_WRONG_PASSPHRASE; |
548 | goto error; |
549 | } |
550 | |
551 | /* Expect a load of INTEGERs. */ |
552 | if (key->type == OSSH_RSA) |
553 | num_integers = 9; |
554 | else if (key->type == OSSH_DSA) |
555 | num_integers = 6; |
224f397a |
556 | else |
557 | num_integers = 0; /* placate compiler warnings */ |
9dda6459 |
558 | |
559 | /* |
560 | * Space to create key blob in. |
561 | */ |
ee5c1422 |
562 | blobsize = 256+key->keyblob_len; |
3d88e64d |
563 | blob = snewn(blobsize, unsigned char); |
9dda6459 |
564 | PUT_32BIT(blob, 7); |
565 | if (key->type == OSSH_DSA) |
566 | memcpy(blob+4, "ssh-dss", 7); |
567 | else if (key->type == OSSH_RSA) |
568 | memcpy(blob+4, "ssh-rsa", 7); |
569 | blobptr = 4+7; |
570 | privptr = -1; |
571 | |
572 | for (i = 0; i < num_integers; i++) { |
573 | ret = ber_read_id_len(p, key->keyblob+key->keyblob_len-p, |
574 | &id, &len, &flags); |
575 | p += ret; |
576 | if (ret < 0 || id != 2 || |
577 | key->keyblob+key->keyblob_len-p < len) { |
578 | errmsg = "ASN.1 decoding failure"; |
1bb20a38 |
579 | retval = SSH2_WRONG_PASSPHRASE; |
9dda6459 |
580 | goto error; |
581 | } |
582 | |
583 | if (i == 0) { |
584 | /* |
585 | * The first integer should be zero always (I think |
586 | * this is some sort of version indication). |
587 | */ |
588 | if (len != 1 || p[0] != 0) { |
1e87cce5 |
589 | errmsg = "version number mismatch"; |
9dda6459 |
590 | goto error; |
591 | } |
592 | } else if (key->type == OSSH_RSA) { |
593 | /* |
594 | * Integers 1 and 2 go into the public blob but in the |
595 | * opposite order; integers 3, 4, 5 and 8 go into the |
596 | * private blob. The other two (6 and 7) are ignored. |
597 | */ |
598 | if (i == 1) { |
599 | /* Save the details for after we deal with number 2. */ |
201188af |
600 | modptr = (char *)p; |
9dda6459 |
601 | modlen = len; |
602 | } else if (i != 6 && i != 7) { |
603 | PUT_32BIT(blob+blobptr, len); |
604 | memcpy(blob+blobptr+4, p, len); |
605 | blobptr += 4+len; |
606 | if (i == 2) { |
607 | PUT_32BIT(blob+blobptr, modlen); |
608 | memcpy(blob+blobptr+4, modptr, modlen); |
609 | blobptr += 4+modlen; |
610 | privptr = blobptr; |
611 | } |
612 | } |
613 | } else if (key->type == OSSH_DSA) { |
614 | /* |
615 | * Integers 1-4 go into the public blob; integer 5 goes |
616 | * into the private blob. |
617 | */ |
618 | PUT_32BIT(blob+blobptr, len); |
619 | memcpy(blob+blobptr+4, p, len); |
620 | blobptr += 4+len; |
621 | if (i == 4) |
622 | privptr = blobptr; |
623 | } |
624 | |
625 | /* Skip past the number. */ |
626 | p += len; |
627 | } |
628 | |
629 | /* |
630 | * Now put together the actual key. Simplest way to do this is |
631 | * to assemble our own key blobs and feed them to the createkey |
632 | * functions; this is a bit faffy but it does mean we get all |
633 | * the sanity checks for free. |
634 | */ |
635 | assert(privptr > 0); /* should have bombed by now if not */ |
3d88e64d |
636 | retkey = snew(struct ssh2_userkey); |
9dda6459 |
637 | retkey->alg = (key->type == OSSH_RSA ? &ssh_rsa : &ssh_dss); |
638 | retkey->data = retkey->alg->createkey(blob, privptr, |
639 | blob+privptr, blobptr-privptr); |
640 | if (!retkey->data) { |
641 | sfree(retkey); |
642 | errmsg = "unable to create key data structure"; |
643 | goto error; |
644 | } |
645 | |
646 | retkey->comment = dupstr("imported-openssh-key"); |
ee5c1422 |
647 | errmsg = NULL; /* no error */ |
648 | retval = retkey; |
9dda6459 |
649 | |
650 | error: |
ee5c1422 |
651 | if (blob) { |
652 | memset(blob, 0, blobsize); |
653 | sfree(blob); |
654 | } |
655 | memset(key->keyblob, 0, key->keyblob_size); |
9dda6459 |
656 | sfree(key->keyblob); |
fb8344c9 |
657 | memset(key, 0, sizeof(*key)); |
9dda6459 |
658 | sfree(key); |
1e87cce5 |
659 | if (errmsg_p) *errmsg_p = errmsg; |
9dda6459 |
660 | return retval; |
661 | } |
7b4ef1ae |
662 | |
9a30e26b |
663 | int openssh_write(const Filename *filename, struct ssh2_userkey *key, |
664 | char *passphrase) |
d23a9b21 |
665 | { |
666 | unsigned char *pubblob, *privblob, *spareblob; |
224f397a |
667 | int publen, privlen, sparelen = 0; |
d23a9b21 |
668 | unsigned char *outblob; |
669 | int outlen; |
670 | struct mpint_pos numbers[9]; |
671 | int nnumbers, pos, len, seqlen, i; |
672 | char *header, *footer; |
673 | char zero[1]; |
674 | unsigned char iv[8]; |
675 | int ret = 0; |
676 | FILE *fp; |
677 | |
678 | /* |
679 | * Fetch the key blobs. |
680 | */ |
681 | pubblob = key->alg->public_blob(key->data, &publen); |
682 | privblob = key->alg->private_blob(key->data, &privlen); |
683 | spareblob = outblob = NULL; |
684 | |
685 | /* |
686 | * Find the sequence of integers to be encoded into the OpenSSH |
687 | * key blob, and also decide on the header line. |
688 | */ |
689 | if (key->alg == &ssh_rsa) { |
690 | int pos; |
691 | struct mpint_pos n, e, d, p, q, iqmp, dmp1, dmq1; |
692 | Bignum bd, bp, bq, bdmp1, bdmq1; |
693 | |
694 | pos = 4 + GET_32BIT(pubblob); |
695 | pos += ssh2_read_mpint(pubblob+pos, publen-pos, &e); |
696 | pos += ssh2_read_mpint(pubblob+pos, publen-pos, &n); |
697 | pos = 0; |
698 | pos += ssh2_read_mpint(privblob+pos, privlen-pos, &d); |
699 | pos += ssh2_read_mpint(privblob+pos, privlen-pos, &p); |
700 | pos += ssh2_read_mpint(privblob+pos, privlen-pos, &q); |
701 | pos += ssh2_read_mpint(privblob+pos, privlen-pos, &iqmp); |
702 | |
703 | assert(e.start && iqmp.start); /* can't go wrong */ |
704 | |
705 | /* We also need d mod (p-1) and d mod (q-1). */ |
706 | bd = bignum_from_bytes(d.start, d.bytes); |
707 | bp = bignum_from_bytes(p.start, p.bytes); |
708 | bq = bignum_from_bytes(q.start, q.bytes); |
709 | decbn(bp); |
710 | decbn(bq); |
711 | bdmp1 = bigmod(bd, bp); |
712 | bdmq1 = bigmod(bd, bq); |
713 | freebn(bd); |
714 | freebn(bp); |
715 | freebn(bq); |
716 | |
717 | dmp1.bytes = (bignum_bitcount(bdmp1)+8)/8; |
718 | dmq1.bytes = (bignum_bitcount(bdmq1)+8)/8; |
719 | sparelen = dmp1.bytes + dmq1.bytes; |
3d88e64d |
720 | spareblob = snewn(sparelen, unsigned char); |
d23a9b21 |
721 | dmp1.start = spareblob; |
722 | dmq1.start = spareblob + dmp1.bytes; |
723 | for (i = 0; i < dmp1.bytes; i++) |
724 | spareblob[i] = bignum_byte(bdmp1, dmp1.bytes-1 - i); |
725 | for (i = 0; i < dmq1.bytes; i++) |
726 | spareblob[i+dmp1.bytes] = bignum_byte(bdmq1, dmq1.bytes-1 - i); |
727 | freebn(bdmp1); |
728 | freebn(bdmq1); |
729 | |
730 | numbers[0].start = zero; numbers[0].bytes = 1; zero[0] = '\0'; |
731 | numbers[1] = n; |
732 | numbers[2] = e; |
733 | numbers[3] = d; |
734 | numbers[4] = p; |
735 | numbers[5] = q; |
736 | numbers[6] = dmp1; |
737 | numbers[7] = dmq1; |
738 | numbers[8] = iqmp; |
739 | |
740 | nnumbers = 9; |
741 | header = "-----BEGIN RSA PRIVATE KEY-----\n"; |
742 | footer = "-----END RSA PRIVATE KEY-----\n"; |
743 | } else if (key->alg == &ssh_dss) { |
744 | int pos; |
745 | struct mpint_pos p, q, g, y, x; |
746 | |
747 | pos = 4 + GET_32BIT(pubblob); |
748 | pos += ssh2_read_mpint(pubblob+pos, publen-pos, &p); |
749 | pos += ssh2_read_mpint(pubblob+pos, publen-pos, &q); |
750 | pos += ssh2_read_mpint(pubblob+pos, publen-pos, &g); |
751 | pos += ssh2_read_mpint(pubblob+pos, publen-pos, &y); |
752 | pos = 0; |
753 | pos += ssh2_read_mpint(privblob+pos, privlen-pos, &x); |
754 | |
755 | assert(y.start && x.start); /* can't go wrong */ |
756 | |
757 | numbers[0].start = zero; numbers[0].bytes = 1; zero[0] = '\0'; |
758 | numbers[1] = p; |
759 | numbers[2] = q; |
760 | numbers[3] = g; |
761 | numbers[4] = y; |
762 | numbers[5] = x; |
763 | |
764 | nnumbers = 6; |
765 | header = "-----BEGIN DSA PRIVATE KEY-----\n"; |
766 | footer = "-----END DSA PRIVATE KEY-----\n"; |
767 | } else { |
768 | assert(0); /* zoinks! */ |
8815b68b |
769 | exit(1); /* XXX: GCC doesn't understand assert() on some systems. */ |
d23a9b21 |
770 | } |
771 | |
772 | /* |
773 | * Now count up the total size of the ASN.1 encoded integers, |
774 | * so as to determine the length of the containing SEQUENCE. |
775 | */ |
776 | len = 0; |
777 | for (i = 0; i < nnumbers; i++) { |
778 | len += ber_write_id_len(NULL, 2, numbers[i].bytes, 0); |
779 | len += numbers[i].bytes; |
780 | } |
781 | seqlen = len; |
782 | /* Now add on the SEQUENCE header. */ |
783 | len += ber_write_id_len(NULL, 16, seqlen, ASN1_CONSTRUCTED); |
04627c33 |
784 | /* Round up to the cipher block size, ensuring we have at least one |
785 | * byte of padding (see below). */ |
786 | outlen = len; |
d23a9b21 |
787 | if (passphrase) |
04627c33 |
788 | outlen = (outlen+8) &~ 7; |
d23a9b21 |
789 | |
790 | /* |
791 | * Now we know how big outblob needs to be. Allocate it. |
792 | */ |
3d88e64d |
793 | outblob = snewn(outlen, unsigned char); |
d23a9b21 |
794 | |
795 | /* |
796 | * And write the data into it. |
797 | */ |
798 | pos = 0; |
799 | pos += ber_write_id_len(outblob+pos, 16, seqlen, ASN1_CONSTRUCTED); |
800 | for (i = 0; i < nnumbers; i++) { |
801 | pos += ber_write_id_len(outblob+pos, 2, numbers[i].bytes, 0); |
802 | memcpy(outblob+pos, numbers[i].start, numbers[i].bytes); |
803 | pos += numbers[i].bytes; |
804 | } |
04627c33 |
805 | |
806 | /* |
807 | * Padding on OpenSSH keys is deterministic. The number of |
808 | * padding bytes is always more than zero, and always at most |
809 | * the cipher block length. The value of each padding byte is |
810 | * equal to the number of padding bytes. So a plaintext that's |
811 | * an exact multiple of the block size will be padded with 08 |
812 | * 08 08 08 08 08 08 08 (assuming a 64-bit block cipher); a |
813 | * plaintext one byte less than a multiple of the block size |
814 | * will be padded with just 01. |
815 | * |
816 | * This enables the OpenSSL key decryption function to strip |
817 | * off the padding algorithmically and return the unpadded |
818 | * plaintext to the next layer: it looks at the final byte, and |
819 | * then expects to find that many bytes at the end of the data |
820 | * with the same value. Those are all removed and the rest is |
821 | * returned. |
822 | */ |
823 | assert(pos == len); |
d23a9b21 |
824 | while (pos < outlen) { |
04627c33 |
825 | outblob[pos++] = outlen - len; |
d23a9b21 |
826 | } |
827 | |
828 | /* |
829 | * Encrypt the key. |
830 | */ |
831 | if (passphrase) { |
832 | /* |
833 | * Invent an iv. Then derive encryption key from passphrase |
834 | * and iv/salt: |
835 | * |
836 | * - let block A equal MD5(passphrase || iv) |
837 | * - let block B equal MD5(A || passphrase || iv) |
838 | * - block C would be MD5(B || passphrase || iv) and so on |
839 | * - encryption key is the first N bytes of A || B |
840 | */ |
841 | struct MD5Context md5c; |
842 | unsigned char keybuf[32]; |
843 | |
844 | for (i = 0; i < 8; i++) iv[i] = random_byte(); |
845 | |
846 | MD5Init(&md5c); |
201188af |
847 | MD5Update(&md5c, (unsigned char *)passphrase, strlen(passphrase)); |
d23a9b21 |
848 | MD5Update(&md5c, iv, 8); |
849 | MD5Final(keybuf, &md5c); |
850 | |
851 | MD5Init(&md5c); |
852 | MD5Update(&md5c, keybuf, 16); |
201188af |
853 | MD5Update(&md5c, (unsigned char *)passphrase, strlen(passphrase)); |
d23a9b21 |
854 | MD5Update(&md5c, iv, 8); |
855 | MD5Final(keybuf+16, &md5c); |
856 | |
857 | /* |
858 | * Now encrypt the key blob. |
859 | */ |
860 | des3_encrypt_pubkey_ossh(keybuf, iv, outblob, outlen); |
861 | |
862 | memset(&md5c, 0, sizeof(md5c)); |
863 | memset(keybuf, 0, sizeof(keybuf)); |
864 | } |
865 | |
866 | /* |
867 | * And save it. We'll use Unix line endings just in case it's |
868 | * subsequently transferred in binary mode. |
869 | */ |
9a30e26b |
870 | fp = f_open(*filename, "wb"); /* ensure Unix line endings */ |
d23a9b21 |
871 | if (!fp) |
872 | goto error; |
873 | fputs(header, fp); |
874 | if (passphrase) { |
875 | fprintf(fp, "Proc-Type: 4,ENCRYPTED\nDEK-Info: DES-EDE3-CBC,"); |
876 | for (i = 0; i < 8; i++) |
877 | fprintf(fp, "%02X", iv[i]); |
878 | fprintf(fp, "\n\n"); |
879 | } |
96d19bc9 |
880 | base64_encode(fp, outblob, outlen, 64); |
d23a9b21 |
881 | fputs(footer, fp); |
882 | fclose(fp); |
883 | ret = 1; |
884 | |
885 | error: |
886 | if (outblob) { |
887 | memset(outblob, 0, outlen); |
888 | sfree(outblob); |
889 | } |
890 | if (spareblob) { |
891 | memset(spareblob, 0, sparelen); |
892 | sfree(spareblob); |
893 | } |
894 | if (privblob) { |
895 | memset(privblob, 0, privlen); |
896 | sfree(privblob); |
897 | } |
898 | if (pubblob) { |
899 | memset(pubblob, 0, publen); |
900 | sfree(pubblob); |
901 | } |
902 | return ret; |
903 | } |
904 | |
7b4ef1ae |
905 | /* ---------------------------------------------------------------------- |
906 | * Code to read ssh.com private keys. |
907 | */ |
908 | |
909 | /* |
2e85c969 |
910 | * The format of the base64 blob is largely SSH-2-packet-formatted, |
7b4ef1ae |
911 | * except that mpints are a bit different: they're more like the |
2e85c969 |
912 | * old SSH-1 mpint. You have a 32-bit bit count N, followed by |
7b4ef1ae |
913 | * (N+7)/8 bytes of data. |
914 | * |
915 | * So. The blob contains: |
916 | * |
917 | * - uint32 0x3f6ff9eb (magic number) |
918 | * - uint32 size (total blob size) |
919 | * - string key-type (see below) |
920 | * - string cipher-type (tells you if key is encrypted) |
921 | * - string encrypted-blob |
922 | * |
923 | * (The first size field includes the size field itself and the |
2e85c969 |
924 | * magic number before it. All other size fields are ordinary SSH-2 |
7b4ef1ae |
925 | * strings, so the size field indicates how much data is to |
926 | * _follow_.) |
927 | * |
928 | * The encrypted blob, once decrypted, contains a single string |
929 | * which in turn contains the payload. (This allows padding to be |
930 | * added after that string while still making it clear where the |
931 | * real payload ends. Also it probably makes for a reasonable |
932 | * decryption check.) |
933 | * |
934 | * The payload blob, for an RSA key, contains: |
935 | * - mpint e |
936 | * - mpint d |
937 | * - mpint n (yes, the public and private stuff is intermixed) |
938 | * - mpint u (presumably inverse of p mod q) |
939 | * - mpint p (p is the smaller prime) |
940 | * - mpint q (q is the larger) |
941 | * |
942 | * For a DSA key, the payload blob contains: |
943 | * - uint32 0 |
944 | * - mpint p |
945 | * - mpint g |
946 | * - mpint q |
947 | * - mpint y |
948 | * - mpint x |
949 | * |
950 | * Alternatively, if the parameters are `predefined', that |
951 | * (0,p,g,q) sequence can be replaced by a uint32 1 and a string |
952 | * containing some predefined parameter specification. *shudder*, |
953 | * but I doubt we'll encounter this in real life. |
954 | * |
955 | * The key type strings are ghastly. The RSA key I looked at had a |
956 | * type string of |
957 | * |
958 | * `if-modn{sign{rsa-pkcs1-sha1},encrypt{rsa-pkcs1v2-oaep}}' |
959 | * |
960 | * and the DSA key wasn't much better: |
961 | * |
962 | * `dl-modp{sign{dsa-nist-sha1},dh{plain}}' |
963 | * |
964 | * It isn't clear that these will always be the same. I think it |
965 | * might be wise just to look at the `if-modn{sign{rsa' and |
966 | * `dl-modp{sign{dsa' prefixes. |
967 | * |
968 | * Finally, the encryption. The cipher-type string appears to be |
2e85c969 |
969 | * either `none' or `3des-cbc'. Looks as if this is SSH-2-style |
7b4ef1ae |
970 | * 3des-cbc (i.e. outer cbc rather than inner). The key is created |
971 | * from the passphrase by means of yet another hashing faff: |
972 | * |
973 | * - first 16 bytes are MD5(passphrase) |
974 | * - next 16 bytes are MD5(passphrase || first 16 bytes) |
975 | * - if there were more, they'd be MD5(passphrase || first 32), |
976 | * and so on. |
977 | */ |
978 | |
96d19bc9 |
979 | #define SSHCOM_MAGIC_NUMBER 0x3f6ff9eb |
980 | |
7b4ef1ae |
981 | struct sshcom_key { |
982 | char comment[256]; /* allowing any length is overkill */ |
983 | unsigned char *keyblob; |
984 | int keyblob_len, keyblob_size; |
985 | }; |
986 | |
1e87cce5 |
987 | static struct sshcom_key *load_sshcom_key(const Filename *filename, |
988 | const char **errmsg_p) |
7b4ef1ae |
989 | { |
990 | struct sshcom_key *ret; |
991 | FILE *fp; |
992 | char buffer[256]; |
993 | int len; |
994 | char *errmsg, *p; |
995 | int headers_done; |
996 | char base64_bit[4]; |
997 | int base64_chars = 0; |
998 | |
3d88e64d |
999 | ret = snew(struct sshcom_key); |
7b4ef1ae |
1000 | ret->comment[0] = '\0'; |
1001 | ret->keyblob = NULL; |
1002 | ret->keyblob_len = ret->keyblob_size = 0; |
1003 | |
9a30e26b |
1004 | fp = f_open(*filename, "r"); |
7b4ef1ae |
1005 | if (!fp) { |
1e87cce5 |
1006 | errmsg = "unable to open key file"; |
7b4ef1ae |
1007 | goto error; |
1008 | } |
1009 | if (!fgets(buffer, sizeof(buffer), fp) || |
1010 | 0 != strcmp(buffer, "---- BEGIN SSH2 ENCRYPTED PRIVATE KEY ----\n")) { |
1e87cce5 |
1011 | errmsg = "file does not begin with ssh.com key header"; |
7b4ef1ae |
1012 | goto error; |
1013 | } |
1014 | |
1015 | headers_done = 0; |
1016 | while (1) { |
1017 | if (!fgets(buffer, sizeof(buffer), fp)) { |
1e87cce5 |
1018 | errmsg = "unexpected end of file"; |
7b4ef1ae |
1019 | goto error; |
1020 | } |
1021 | if (!strcmp(buffer, "---- END SSH2 ENCRYPTED PRIVATE KEY ----\n")) |
1022 | break; /* done */ |
1023 | if ((p = strchr(buffer, ':')) != NULL) { |
1024 | if (headers_done) { |
1e87cce5 |
1025 | errmsg = "header found in body of key data"; |
7b4ef1ae |
1026 | goto error; |
1027 | } |
1028 | *p++ = '\0'; |
1029 | while (*p && isspace((unsigned char)*p)) p++; |
1030 | /* |
1031 | * Header lines can end in a trailing backslash for |
1032 | * continuation. |
1033 | */ |
6ef15436 |
1034 | while ((len = strlen(p)) > (int)(sizeof(buffer) - (p-buffer) -1) || |
7b4ef1ae |
1035 | p[len-1] != '\n' || p[len-2] == '\\') { |
6ef15436 |
1036 | if (len > (int)((p-buffer) + sizeof(buffer)-2)) { |
1e87cce5 |
1037 | errmsg = "header line too long to deal with"; |
7b4ef1ae |
1038 | goto error; |
1039 | } |
1040 | if (!fgets(p+len-2, sizeof(buffer)-(p-buffer)-(len-2), fp)) { |
1e87cce5 |
1041 | errmsg = "unexpected end of file"; |
7b4ef1ae |
1042 | goto error; |
1043 | } |
1044 | } |
1045 | p[strcspn(p, "\n")] = '\0'; |
1046 | if (!strcmp(buffer, "Comment")) { |
1047 | /* Strip quotes in comment if present. */ |
1048 | if (p[0] == '"' && p[strlen(p)-1] == '"') { |
1049 | p++; |
1050 | p[strlen(p)-1] = '\0'; |
1051 | } |
1052 | strncpy(ret->comment, p, sizeof(ret->comment)); |
1053 | ret->comment[sizeof(ret->comment)-1] = '\0'; |
1054 | } |
1055 | } else { |
1056 | headers_done = 1; |
1057 | |
1058 | p = buffer; |
1059 | while (isbase64(*p)) { |
1060 | base64_bit[base64_chars++] = *p; |
1061 | if (base64_chars == 4) { |
1062 | unsigned char out[3]; |
1063 | |
1064 | base64_chars = 0; |
1065 | |
1066 | len = base64_decode_atom(base64_bit, out); |
1067 | |
1068 | if (len <= 0) { |
1e87cce5 |
1069 | errmsg = "invalid base64 encoding"; |
7b4ef1ae |
1070 | goto error; |
1071 | } |
1072 | |
1073 | if (ret->keyblob_len + len > ret->keyblob_size) { |
1074 | ret->keyblob_size = ret->keyblob_len + len + 256; |
3d88e64d |
1075 | ret->keyblob = sresize(ret->keyblob, ret->keyblob_size, |
1076 | unsigned char); |
7b4ef1ae |
1077 | } |
1078 | |
1079 | memcpy(ret->keyblob + ret->keyblob_len, out, len); |
1080 | ret->keyblob_len += len; |
1081 | } |
1082 | |
1083 | p++; |
1084 | } |
1085 | } |
1086 | } |
1087 | |
1088 | if (ret->keyblob_len == 0 || !ret->keyblob) { |
1e87cce5 |
1089 | errmsg = "key body not present"; |
7b4ef1ae |
1090 | goto error; |
1091 | } |
1092 | |
1e87cce5 |
1093 | if (errmsg_p) *errmsg_p = NULL; |
7b4ef1ae |
1094 | return ret; |
1095 | |
1096 | error: |
1097 | if (ret) { |
ee5c1422 |
1098 | if (ret->keyblob) { |
1099 | memset(ret->keyblob, 0, ret->keyblob_size); |
1100 | sfree(ret->keyblob); |
1101 | } |
fb8344c9 |
1102 | memset(ret, 0, sizeof(*ret)); |
7b4ef1ae |
1103 | sfree(ret); |
1104 | } |
1e87cce5 |
1105 | if (errmsg_p) *errmsg_p = errmsg; |
7b4ef1ae |
1106 | return NULL; |
1107 | } |
1108 | |
9a30e26b |
1109 | int sshcom_encrypted(const Filename *filename, char **comment) |
7b4ef1ae |
1110 | { |
1e87cce5 |
1111 | struct sshcom_key *key = load_sshcom_key(filename, NULL); |
7b4ef1ae |
1112 | int pos, len, answer; |
1113 | |
1114 | *comment = NULL; |
1115 | if (!key) |
1116 | return 0; |
1117 | |
1118 | /* |
1119 | * Check magic number. |
1120 | */ |
1121 | if (GET_32BIT(key->keyblob) != 0x3f6ff9eb) |
1122 | return 0; /* key is invalid */ |
1123 | |
1124 | /* |
1125 | * Find the cipher-type string. |
1126 | */ |
1127 | answer = 0; |
1128 | pos = 8; |
1129 | if (key->keyblob_len < pos+4) |
1130 | goto done; /* key is far too short */ |
1131 | pos += 4 + GET_32BIT(key->keyblob + pos); /* skip key type */ |
1132 | if (key->keyblob_len < pos+4) |
1133 | goto done; /* key is far too short */ |
1134 | len = GET_32BIT(key->keyblob + pos); /* find cipher-type length */ |
1135 | if (key->keyblob_len < pos+4+len) |
1136 | goto done; /* cipher type string is incomplete */ |
1137 | if (len != 4 || 0 != memcmp(key->keyblob + pos + 4, "none", 4)) |
1138 | answer = 1; |
1139 | |
1140 | done: |
1141 | *comment = dupstr(key->comment); |
ee5c1422 |
1142 | memset(key->keyblob, 0, key->keyblob_size); |
7b4ef1ae |
1143 | sfree(key->keyblob); |
fb8344c9 |
1144 | memset(key, 0, sizeof(*key)); |
7b4ef1ae |
1145 | sfree(key); |
1146 | return answer; |
1147 | } |
1148 | |
d714d740 |
1149 | static int sshcom_read_mpint(void *data, int len, struct mpint_pos *ret) |
7b4ef1ae |
1150 | { |
1151 | int bits; |
1152 | int bytes; |
1153 | unsigned char *d = (unsigned char *) data; |
1154 | |
1155 | if (len < 4) |
1156 | goto error; |
1157 | bits = GET_32BIT(d); |
1158 | |
1159 | bytes = (bits + 7) / 8; |
1160 | if (len < 4+bytes) |
1161 | goto error; |
1162 | |
1163 | ret->start = d + 4; |
1164 | ret->bytes = bytes; |
1165 | return bytes+4; |
1166 | |
1167 | error: |
1168 | ret->start = NULL; |
1169 | ret->bytes = -1; |
1170 | return len; /* ensure further calls fail as well */ |
1171 | } |
1172 | |
96d19bc9 |
1173 | static int sshcom_put_mpint(void *target, void *data, int len) |
1174 | { |
1175 | unsigned char *d = (unsigned char *)target; |
1176 | unsigned char *i = (unsigned char *)data; |
1177 | int bits = len * 8 - 1; |
1178 | |
1179 | while (bits > 0) { |
1180 | if (*i & (1 << (bits & 7))) |
1181 | break; |
1182 | if (!(bits-- & 7)) |
1183 | i++, len--; |
1184 | } |
1185 | |
1186 | PUT_32BIT(d, bits+1); |
1187 | memcpy(d+4, i, len); |
1188 | return len+4; |
1189 | } |
1190 | |
1e87cce5 |
1191 | struct ssh2_userkey *sshcom_read(const Filename *filename, char *passphrase, |
1192 | const char **errmsg_p) |
7b4ef1ae |
1193 | { |
1e87cce5 |
1194 | struct sshcom_key *key = load_sshcom_key(filename, errmsg_p); |
7b4ef1ae |
1195 | char *errmsg; |
1196 | int pos, len; |
1197 | const char prefix_rsa[] = "if-modn{sign{rsa"; |
1198 | const char prefix_dsa[] = "dl-modp{sign{dsa"; |
1199 | enum { RSA, DSA } type; |
1200 | int encrypted; |
1201 | char *ciphertext; |
1202 | int cipherlen; |
1203 | struct ssh2_userkey *ret = NULL, *retkey; |
1204 | const struct ssh_signkey *alg; |
1205 | unsigned char *blob = NULL; |
224f397a |
1206 | int blobsize = 0, publen, privlen; |
7b4ef1ae |
1207 | |
1208 | if (!key) |
1209 | return NULL; |
1210 | |
1211 | /* |
1212 | * Check magic number. |
1213 | */ |
96d19bc9 |
1214 | if (GET_32BIT(key->keyblob) != SSHCOM_MAGIC_NUMBER) { |
1e87cce5 |
1215 | errmsg = "key does not begin with magic number"; |
7b4ef1ae |
1216 | goto error; |
1217 | } |
1218 | |
1219 | /* |
1220 | * Determine the key type. |
1221 | */ |
1222 | pos = 8; |
1223 | if (key->keyblob_len < pos+4 || |
1224 | (len = GET_32BIT(key->keyblob + pos)) > key->keyblob_len - pos - 4) { |
1e87cce5 |
1225 | errmsg = "key blob does not contain a key type string"; |
7b4ef1ae |
1226 | goto error; |
1227 | } |
1228 | if (len > sizeof(prefix_rsa) - 1 && |
1229 | !memcmp(key->keyblob+pos+4, prefix_rsa, sizeof(prefix_rsa) - 1)) { |
1230 | type = RSA; |
1231 | } else if (len > sizeof(prefix_dsa) - 1 && |
1232 | !memcmp(key->keyblob+pos+4, prefix_dsa, sizeof(prefix_dsa) - 1)) { |
1233 | type = DSA; |
1234 | } else { |
1e87cce5 |
1235 | errmsg = "key is of unknown type"; |
7b4ef1ae |
1236 | goto error; |
1237 | } |
1238 | pos += 4+len; |
1239 | |
1240 | /* |
1241 | * Determine the cipher type. |
1242 | */ |
1243 | if (key->keyblob_len < pos+4 || |
1244 | (len = GET_32BIT(key->keyblob + pos)) > key->keyblob_len - pos - 4) { |
1e87cce5 |
1245 | errmsg = "key blob does not contain a cipher type string"; |
7b4ef1ae |
1246 | goto error; |
1247 | } |
1248 | if (len == 4 && !memcmp(key->keyblob+pos+4, "none", 4)) |
1249 | encrypted = 0; |
1250 | else if (len == 8 && !memcmp(key->keyblob+pos+4, "3des-cbc", 8)) |
1251 | encrypted = 1; |
1252 | else { |
1e87cce5 |
1253 | errmsg = "key encryption is of unknown type"; |
7b4ef1ae |
1254 | goto error; |
1255 | } |
1256 | pos += 4+len; |
1257 | |
1258 | /* |
1259 | * Get hold of the encrypted part of the key. |
1260 | */ |
1261 | if (key->keyblob_len < pos+4 || |
1262 | (len = GET_32BIT(key->keyblob + pos)) > key->keyblob_len - pos - 4) { |
1e87cce5 |
1263 | errmsg = "key blob does not contain actual key data"; |
7b4ef1ae |
1264 | goto error; |
1265 | } |
201188af |
1266 | ciphertext = (char *)key->keyblob + pos + 4; |
7b4ef1ae |
1267 | cipherlen = len; |
1268 | if (cipherlen == 0) { |
1e87cce5 |
1269 | errmsg = "length of key data is zero"; |
7b4ef1ae |
1270 | goto error; |
1271 | } |
1272 | |
1273 | /* |
1274 | * Decrypt it if necessary. |
1275 | */ |
1276 | if (encrypted) { |
1277 | /* |
1278 | * Derive encryption key from passphrase and iv/salt: |
1279 | * |
1280 | * - let block A equal MD5(passphrase) |
1281 | * - let block B equal MD5(passphrase || A) |
1282 | * - block C would be MD5(passphrase || A || B) and so on |
1283 | * - encryption key is the first N bytes of A || B |
1284 | */ |
1285 | struct MD5Context md5c; |
1286 | unsigned char keybuf[32], iv[8]; |
1287 | |
1288 | if (cipherlen % 8 != 0) { |
1e87cce5 |
1289 | errmsg = "encrypted part of key is not a multiple of cipher block" |
7b4ef1ae |
1290 | " size"; |
1291 | goto error; |
1292 | } |
1293 | |
1294 | MD5Init(&md5c); |
201188af |
1295 | MD5Update(&md5c, (unsigned char *)passphrase, strlen(passphrase)); |
7b4ef1ae |
1296 | MD5Final(keybuf, &md5c); |
1297 | |
1298 | MD5Init(&md5c); |
201188af |
1299 | MD5Update(&md5c, (unsigned char *)passphrase, strlen(passphrase)); |
7b4ef1ae |
1300 | MD5Update(&md5c, keybuf, 16); |
1301 | MD5Final(keybuf+16, &md5c); |
1302 | |
1303 | /* |
1304 | * Now decrypt the key blob. |
1305 | */ |
ee5c1422 |
1306 | memset(iv, 0, sizeof(iv)); |
201188af |
1307 | des3_decrypt_pubkey_ossh(keybuf, iv, (unsigned char *)ciphertext, |
1308 | cipherlen); |
7b4ef1ae |
1309 | |
ee5c1422 |
1310 | memset(&md5c, 0, sizeof(md5c)); |
1311 | memset(keybuf, 0, sizeof(keybuf)); |
1312 | |
7b4ef1ae |
1313 | /* |
1314 | * Hereafter we return WRONG_PASSPHRASE for any parsing |
ee5c1422 |
1315 | * error. (But only if we've just tried to decrypt it! |
1316 | * Returning WRONG_PASSPHRASE for an unencrypted key is |
1317 | * automatic doom.) |
7b4ef1ae |
1318 | */ |
1319 | if (encrypted) |
1320 | ret = SSH2_WRONG_PASSPHRASE; |
1321 | } |
1322 | |
1323 | /* |
1324 | * Strip away the containing string to get to the real meat. |
1325 | */ |
1326 | len = GET_32BIT(ciphertext); |
1bb20a38 |
1327 | if (len < 0 || len > cipherlen-4) { |
7b4ef1ae |
1328 | errmsg = "containing string was ill-formed"; |
1329 | goto error; |
1330 | } |
1331 | ciphertext += 4; |
1332 | cipherlen = len; |
1333 | |
1334 | /* |
1335 | * Now we break down into RSA versus DSA. In either case we'll |
1336 | * construct public and private blobs in our own format, and |
1337 | * end up feeding them to alg->createkey(). |
1338 | */ |
ee5c1422 |
1339 | blobsize = cipherlen + 256; |
3d88e64d |
1340 | blob = snewn(blobsize, unsigned char); |
7b4ef1ae |
1341 | privlen = 0; |
1342 | if (type == RSA) { |
1343 | struct mpint_pos n, e, d, u, p, q; |
1344 | int pos = 0; |
1345 | pos += sshcom_read_mpint(ciphertext+pos, cipherlen-pos, &e); |
1346 | pos += sshcom_read_mpint(ciphertext+pos, cipherlen-pos, &d); |
1347 | pos += sshcom_read_mpint(ciphertext+pos, cipherlen-pos, &n); |
1348 | pos += sshcom_read_mpint(ciphertext+pos, cipherlen-pos, &u); |
1349 | pos += sshcom_read_mpint(ciphertext+pos, cipherlen-pos, &p); |
1350 | pos += sshcom_read_mpint(ciphertext+pos, cipherlen-pos, &q); |
1351 | if (!q.start) { |
1352 | errmsg = "key data did not contain six integers"; |
1353 | goto error; |
1354 | } |
1355 | |
1356 | alg = &ssh_rsa; |
1357 | pos = 0; |
1358 | pos += put_string(blob+pos, "ssh-rsa", 7); |
1359 | pos += put_mp(blob+pos, e.start, e.bytes); |
1360 | pos += put_mp(blob+pos, n.start, n.bytes); |
1361 | publen = pos; |
1362 | pos += put_string(blob+pos, d.start, d.bytes); |
1363 | pos += put_mp(blob+pos, q.start, q.bytes); |
1364 | pos += put_mp(blob+pos, p.start, p.bytes); |
1365 | pos += put_mp(blob+pos, u.start, u.bytes); |
1366 | privlen = pos - publen; |
1367 | } else if (type == DSA) { |
1368 | struct mpint_pos p, q, g, x, y; |
1369 | int pos = 4; |
1370 | if (GET_32BIT(ciphertext) != 0) { |
1371 | errmsg = "predefined DSA parameters not supported"; |
1372 | goto error; |
1373 | } |
1374 | pos += sshcom_read_mpint(ciphertext+pos, cipherlen-pos, &p); |
1375 | pos += sshcom_read_mpint(ciphertext+pos, cipherlen-pos, &g); |
1376 | pos += sshcom_read_mpint(ciphertext+pos, cipherlen-pos, &q); |
1377 | pos += sshcom_read_mpint(ciphertext+pos, cipherlen-pos, &y); |
1378 | pos += sshcom_read_mpint(ciphertext+pos, cipherlen-pos, &x); |
1379 | if (!x.start) { |
1380 | errmsg = "key data did not contain five integers"; |
1381 | goto error; |
1382 | } |
1383 | |
1384 | alg = &ssh_dss; |
1385 | pos = 0; |
1386 | pos += put_string(blob+pos, "ssh-dss", 7); |
1387 | pos += put_mp(blob+pos, p.start, p.bytes); |
1388 | pos += put_mp(blob+pos, q.start, q.bytes); |
1389 | pos += put_mp(blob+pos, g.start, g.bytes); |
1390 | pos += put_mp(blob+pos, y.start, y.bytes); |
1391 | publen = pos; |
1392 | pos += put_mp(blob+pos, x.start, x.bytes); |
1393 | privlen = pos - publen; |
224f397a |
1394 | } else |
1395 | return NULL; |
7b4ef1ae |
1396 | |
1397 | assert(privlen > 0); /* should have bombed by now if not */ |
1398 | |
3d88e64d |
1399 | retkey = snew(struct ssh2_userkey); |
7b4ef1ae |
1400 | retkey->alg = alg; |
1401 | retkey->data = alg->createkey(blob, publen, blob+publen, privlen); |
1402 | if (!retkey->data) { |
1403 | sfree(retkey); |
1404 | errmsg = "unable to create key data structure"; |
1405 | goto error; |
1406 | } |
1407 | retkey->comment = dupstr(key->comment); |
1408 | |
1409 | errmsg = NULL; /* no error */ |
1410 | ret = retkey; |
1411 | |
1412 | error: |
ee5c1422 |
1413 | if (blob) { |
1414 | memset(blob, 0, blobsize); |
1415 | sfree(blob); |
1416 | } |
1417 | memset(key->keyblob, 0, key->keyblob_size); |
7b4ef1ae |
1418 | sfree(key->keyblob); |
fb8344c9 |
1419 | memset(key, 0, sizeof(*key)); |
7b4ef1ae |
1420 | sfree(key); |
1e87cce5 |
1421 | if (errmsg_p) *errmsg_p = errmsg; |
7b4ef1ae |
1422 | return ret; |
1423 | } |
96d19bc9 |
1424 | |
9a30e26b |
1425 | int sshcom_write(const Filename *filename, struct ssh2_userkey *key, |
1426 | char *passphrase) |
96d19bc9 |
1427 | { |
1428 | unsigned char *pubblob, *privblob; |
1429 | int publen, privlen; |
1430 | unsigned char *outblob; |
1431 | int outlen; |
1432 | struct mpint_pos numbers[6]; |
1433 | int nnumbers, initial_zero, pos, lenpos, i; |
1434 | char *type; |
1435 | char *ciphertext; |
1436 | int cipherlen; |
1437 | int ret = 0; |
1438 | FILE *fp; |
1439 | |
1440 | /* |
1441 | * Fetch the key blobs. |
1442 | */ |
1443 | pubblob = key->alg->public_blob(key->data, &publen); |
1444 | privblob = key->alg->private_blob(key->data, &privlen); |
1445 | outblob = NULL; |
1446 | |
1447 | /* |
1448 | * Find the sequence of integers to be encoded into the OpenSSH |
1449 | * key blob, and also decide on the header line. |
1450 | */ |
1451 | if (key->alg == &ssh_rsa) { |
1452 | int pos; |
1453 | struct mpint_pos n, e, d, p, q, iqmp; |
1454 | |
1455 | pos = 4 + GET_32BIT(pubblob); |
1456 | pos += ssh2_read_mpint(pubblob+pos, publen-pos, &e); |
1457 | pos += ssh2_read_mpint(pubblob+pos, publen-pos, &n); |
1458 | pos = 0; |
1459 | pos += ssh2_read_mpint(privblob+pos, privlen-pos, &d); |
1460 | pos += ssh2_read_mpint(privblob+pos, privlen-pos, &p); |
1461 | pos += ssh2_read_mpint(privblob+pos, privlen-pos, &q); |
1462 | pos += ssh2_read_mpint(privblob+pos, privlen-pos, &iqmp); |
1463 | |
1464 | assert(e.start && iqmp.start); /* can't go wrong */ |
1465 | |
1466 | numbers[0] = e; |
1467 | numbers[1] = d; |
1468 | numbers[2] = n; |
1469 | numbers[3] = iqmp; |
1470 | numbers[4] = q; |
1471 | numbers[5] = p; |
1472 | |
1473 | nnumbers = 6; |
1474 | initial_zero = 0; |
1475 | type = "if-modn{sign{rsa-pkcs1-sha1},encrypt{rsa-pkcs1v2-oaep}}"; |
1476 | } else if (key->alg == &ssh_dss) { |
1477 | int pos; |
1478 | struct mpint_pos p, q, g, y, x; |
1479 | |
1480 | pos = 4 + GET_32BIT(pubblob); |
1481 | pos += ssh2_read_mpint(pubblob+pos, publen-pos, &p); |
1482 | pos += ssh2_read_mpint(pubblob+pos, publen-pos, &q); |
1483 | pos += ssh2_read_mpint(pubblob+pos, publen-pos, &g); |
1484 | pos += ssh2_read_mpint(pubblob+pos, publen-pos, &y); |
1485 | pos = 0; |
1486 | pos += ssh2_read_mpint(privblob+pos, privlen-pos, &x); |
1487 | |
1488 | assert(y.start && x.start); /* can't go wrong */ |
1489 | |
1490 | numbers[0] = p; |
1491 | numbers[1] = g; |
1492 | numbers[2] = q; |
1493 | numbers[3] = y; |
1494 | numbers[4] = x; |
1495 | |
1496 | nnumbers = 5; |
1497 | initial_zero = 1; |
1498 | type = "dl-modp{sign{dsa-nist-sha1},dh{plain}}"; |
1499 | } else { |
1500 | assert(0); /* zoinks! */ |
8815b68b |
1501 | exit(1); /* XXX: GCC doesn't understand assert() on some systems. */ |
96d19bc9 |
1502 | } |
1503 | |
1504 | /* |
1505 | * Total size of key blob will be somewhere under 512 plus |
1506 | * combined length of integers. We'll calculate the more |
1507 | * precise size as we construct the blob. |
1508 | */ |
1509 | outlen = 512; |
1510 | for (i = 0; i < nnumbers; i++) |
1511 | outlen += 4 + numbers[i].bytes; |
3d88e64d |
1512 | outblob = snewn(outlen, unsigned char); |
96d19bc9 |
1513 | |
1514 | /* |
1515 | * Create the unencrypted key blob. |
1516 | */ |
1517 | pos = 0; |
1518 | PUT_32BIT(outblob+pos, SSHCOM_MAGIC_NUMBER); pos += 4; |
1519 | pos += 4; /* length field, fill in later */ |
1520 | pos += put_string(outblob+pos, type, strlen(type)); |
1521 | { |
1522 | char *ciphertype = passphrase ? "3des-cbc" : "none"; |
1523 | pos += put_string(outblob+pos, ciphertype, strlen(ciphertype)); |
1524 | } |
1525 | lenpos = pos; /* remember this position */ |
1526 | pos += 4; /* encrypted-blob size */ |
1527 | pos += 4; /* encrypted-payload size */ |
1528 | if (initial_zero) { |
1529 | PUT_32BIT(outblob+pos, 0); |
1530 | pos += 4; |
1531 | } |
1532 | for (i = 0; i < nnumbers; i++) |
1533 | pos += sshcom_put_mpint(outblob+pos, |
1534 | numbers[i].start, numbers[i].bytes); |
1535 | /* Now wrap up the encrypted payload. */ |
1536 | PUT_32BIT(outblob+lenpos+4, pos - (lenpos+8)); |
1537 | /* Pad encrypted blob to a multiple of cipher block size. */ |
1538 | if (passphrase) { |
1539 | int padding = -(pos - (lenpos+4)) & 7; |
1540 | while (padding--) |
1541 | outblob[pos++] = random_byte(); |
1542 | } |
201188af |
1543 | ciphertext = (char *)outblob+lenpos+4; |
96d19bc9 |
1544 | cipherlen = pos - (lenpos+4); |
1545 | assert(!passphrase || cipherlen % 8 == 0); |
1546 | /* Wrap up the encrypted blob string. */ |
1547 | PUT_32BIT(outblob+lenpos, cipherlen); |
1548 | /* And finally fill in the total length field. */ |
1549 | PUT_32BIT(outblob+4, pos); |
1550 | |
1551 | assert(pos < outlen); |
1552 | |
1553 | /* |
1554 | * Encrypt the key. |
1555 | */ |
1556 | if (passphrase) { |
1557 | /* |
1558 | * Derive encryption key from passphrase and iv/salt: |
1559 | * |
1560 | * - let block A equal MD5(passphrase) |
1561 | * - let block B equal MD5(passphrase || A) |
1562 | * - block C would be MD5(passphrase || A || B) and so on |
1563 | * - encryption key is the first N bytes of A || B |
1564 | */ |
1565 | struct MD5Context md5c; |
1566 | unsigned char keybuf[32], iv[8]; |
1567 | |
1568 | MD5Init(&md5c); |
201188af |
1569 | MD5Update(&md5c, (unsigned char *)passphrase, strlen(passphrase)); |
96d19bc9 |
1570 | MD5Final(keybuf, &md5c); |
1571 | |
1572 | MD5Init(&md5c); |
201188af |
1573 | MD5Update(&md5c, (unsigned char *)passphrase, strlen(passphrase)); |
96d19bc9 |
1574 | MD5Update(&md5c, keybuf, 16); |
1575 | MD5Final(keybuf+16, &md5c); |
1576 | |
1577 | /* |
1578 | * Now decrypt the key blob. |
1579 | */ |
1580 | memset(iv, 0, sizeof(iv)); |
201188af |
1581 | des3_encrypt_pubkey_ossh(keybuf, iv, (unsigned char *)ciphertext, |
1582 | cipherlen); |
96d19bc9 |
1583 | |
1584 | memset(&md5c, 0, sizeof(md5c)); |
1585 | memset(keybuf, 0, sizeof(keybuf)); |
1586 | } |
1587 | |
1588 | /* |
1589 | * And save it. We'll use Unix line endings just in case it's |
1590 | * subsequently transferred in binary mode. |
1591 | */ |
9a30e26b |
1592 | fp = f_open(*filename, "wb"); /* ensure Unix line endings */ |
96d19bc9 |
1593 | if (!fp) |
1594 | goto error; |
1595 | fputs("---- BEGIN SSH2 ENCRYPTED PRIVATE KEY ----\n", fp); |
1596 | fprintf(fp, "Comment: \""); |
1597 | /* |
1598 | * Comment header is broken with backslash-newline if it goes |
1599 | * over 70 chars. Although it's surrounded by quotes, it |
1600 | * _doesn't_ escape backslashes or quotes within the string. |
1601 | * Don't ask me, I didn't design it. |
1602 | */ |
1603 | { |
1604 | int slen = 60; /* starts at 60 due to "Comment: " */ |
1605 | char *c = key->comment; |
6ef15436 |
1606 | while ((int)strlen(c) > slen) { |
96d19bc9 |
1607 | fprintf(fp, "%.*s\\\n", slen, c); |
1608 | c += slen; |
1609 | slen = 70; /* allow 70 chars on subsequent lines */ |
1610 | } |
1611 | fprintf(fp, "%s\"\n", c); |
1612 | } |
1613 | base64_encode(fp, outblob, pos, 70); |
1614 | fputs("---- END SSH2 ENCRYPTED PRIVATE KEY ----\n", fp); |
1615 | fclose(fp); |
1616 | ret = 1; |
1617 | |
1618 | error: |
1619 | if (outblob) { |
1620 | memset(outblob, 0, outlen); |
1621 | sfree(outblob); |
1622 | } |
1623 | if (privblob) { |
1624 | memset(privblob, 0, privlen); |
1625 | sfree(privblob); |
1626 | } |
1627 | if (pubblob) { |
1628 | memset(pubblob, 0, publen); |
1629 | sfree(pubblob); |
1630 | } |
1631 | return ret; |
1632 | } |