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