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Commit | Line | Data |
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1c1af145 | 1 | /* |
2 | * Generic SSH public-key handling operations. In particular, | |
3 | * reading of SSH public-key files, and also the generic `sign' | |
4 | * operation for SSH-2 (which checks the type of the key and | |
5 | * dispatches to the appropriate key-type specific function). | |
6 | */ | |
7 | ||
8 | #include <stdio.h> | |
9 | #include <stdlib.h> | |
10 | #include <assert.h> | |
11 | ||
12 | #include "putty.h" | |
13 | #include "ssh.h" | |
14 | #include "misc.h" | |
15 | ||
16 | #define rsa_signature "SSH PRIVATE KEY FILE FORMAT 1.1\n" | |
17 | ||
18 | #define BASE64_TOINT(x) ( (x)-'A'<26 ? (x)-'A'+0 :\ | |
19 | (x)-'a'<26 ? (x)-'a'+26 :\ | |
20 | (x)-'0'<10 ? (x)-'0'+52 :\ | |
21 | (x)=='+' ? 62 : \ | |
22 | (x)=='/' ? 63 : 0 ) | |
23 | ||
24 | static int loadrsakey_main(FILE * fp, struct RSAKey *key, int pub_only, | |
25 | char **commentptr, char *passphrase, | |
26 | const char **error) | |
27 | { | |
28 | unsigned char buf[16384]; | |
29 | unsigned char keybuf[16]; | |
30 | int len; | |
31 | int i, j, ciphertype; | |
32 | int ret = 0; | |
33 | struct MD5Context md5c; | |
34 | char *comment; | |
35 | ||
36 | *error = NULL; | |
37 | ||
38 | /* Slurp the whole file (minus the header) into a buffer. */ | |
39 | len = fread(buf, 1, sizeof(buf), fp); | |
40 | fclose(fp); | |
41 | if (len < 0 || len == sizeof(buf)) { | |
42 | *error = "error reading file"; | |
43 | goto end; /* file too big or not read */ | |
44 | } | |
45 | ||
46 | i = 0; | |
47 | *error = "file format error"; | |
48 | ||
49 | /* | |
50 | * A zero byte. (The signature includes a terminating NUL.) | |
51 | */ | |
52 | if (len - i < 1 || buf[i] != 0) | |
53 | goto end; | |
54 | i++; | |
55 | ||
56 | /* One byte giving encryption type, and one reserved uint32. */ | |
57 | if (len - i < 1) | |
58 | goto end; | |
59 | ciphertype = buf[i]; | |
60 | if (ciphertype != 0 && ciphertype != SSH_CIPHER_3DES) | |
61 | goto end; | |
62 | i++; | |
63 | if (len - i < 4) | |
64 | goto end; /* reserved field not present */ | |
65 | if (buf[i] != 0 || buf[i + 1] != 0 || buf[i + 2] != 0 | |
66 | || buf[i + 3] != 0) goto end; /* reserved field nonzero, panic! */ | |
67 | i += 4; | |
68 | ||
69 | /* Now the serious stuff. An ordinary SSH-1 public key. */ | |
70 | i += makekey(buf + i, len, key, NULL, 1); | |
71 | if (i < 0) | |
72 | goto end; /* overran */ | |
73 | ||
74 | /* Next, the comment field. */ | |
75 | j = GET_32BIT(buf + i); | |
76 | i += 4; | |
77 | if (len - i < j) | |
78 | goto end; | |
79 | comment = snewn(j + 1, char); | |
80 | if (comment) { | |
81 | memcpy(comment, buf + i, j); | |
82 | comment[j] = '\0'; | |
83 | } | |
84 | i += j; | |
85 | if (commentptr) | |
86 | *commentptr = dupstr(comment); | |
87 | if (key) | |
88 | key->comment = comment; | |
89 | else | |
90 | sfree(comment); | |
91 | ||
92 | if (pub_only) { | |
93 | ret = 1; | |
94 | goto end; | |
95 | } | |
96 | ||
97 | if (!key) { | |
98 | ret = ciphertype != 0; | |
99 | *error = NULL; | |
100 | goto end; | |
101 | } | |
102 | ||
103 | /* | |
104 | * Decrypt remainder of buffer. | |
105 | */ | |
106 | if (ciphertype) { | |
107 | MD5Init(&md5c); | |
108 | MD5Update(&md5c, (unsigned char *)passphrase, strlen(passphrase)); | |
109 | MD5Final(keybuf, &md5c); | |
110 | des3_decrypt_pubkey(keybuf, buf + i, (len - i + 7) & ~7); | |
111 | memset(keybuf, 0, sizeof(keybuf)); /* burn the evidence */ | |
112 | } | |
113 | ||
114 | /* | |
115 | * We are now in the secret part of the key. The first four | |
116 | * bytes should be of the form a, b, a, b. | |
117 | */ | |
118 | if (len - i < 4) | |
119 | goto end; | |
120 | if (buf[i] != buf[i + 2] || buf[i + 1] != buf[i + 3]) { | |
121 | *error = "wrong passphrase"; | |
122 | ret = -1; | |
123 | goto end; | |
124 | } | |
125 | i += 4; | |
126 | ||
127 | /* | |
128 | * After that, we have one further bignum which is our | |
129 | * decryption exponent, and then the three auxiliary values | |
130 | * (iqmp, q, p). | |
131 | */ | |
132 | j = makeprivate(buf + i, len - i, key); | |
133 | if (j < 0) goto end; | |
134 | i += j; | |
135 | j = ssh1_read_bignum(buf + i, len - i, &key->iqmp); | |
136 | if (j < 0) goto end; | |
137 | i += j; | |
138 | j = ssh1_read_bignum(buf + i, len - i, &key->q); | |
139 | if (j < 0) goto end; | |
140 | i += j; | |
141 | j = ssh1_read_bignum(buf + i, len - i, &key->p); | |
142 | if (j < 0) goto end; | |
143 | i += j; | |
144 | ||
145 | if (!rsa_verify(key)) { | |
146 | *error = "rsa_verify failed"; | |
147 | freersakey(key); | |
148 | ret = 0; | |
149 | } else | |
150 | ret = 1; | |
151 | ||
152 | end: | |
153 | memset(buf, 0, sizeof(buf)); /* burn the evidence */ | |
154 | return ret; | |
155 | } | |
156 | ||
157 | int loadrsakey(const Filename *filename, struct RSAKey *key, char *passphrase, | |
158 | const char **errorstr) | |
159 | { | |
160 | FILE *fp; | |
161 | char buf[64]; | |
162 | int ret = 0; | |
163 | const char *error = NULL; | |
164 | ||
165 | fp = f_open(*filename, "rb", FALSE); | |
166 | if (!fp) { | |
167 | error = "can't open file"; | |
168 | goto end; | |
169 | } | |
170 | ||
171 | /* | |
172 | * Read the first line of the file and see if it's a v1 private | |
173 | * key file. | |
174 | */ | |
175 | if (fgets(buf, sizeof(buf), fp) && !strcmp(buf, rsa_signature)) { | |
176 | /* | |
177 | * This routine will take care of calling fclose() for us. | |
178 | */ | |
179 | ret = loadrsakey_main(fp, key, FALSE, NULL, passphrase, &error); | |
180 | fp = NULL; | |
181 | goto end; | |
182 | } | |
183 | ||
184 | /* | |
185 | * Otherwise, we have nothing. Return empty-handed. | |
186 | */ | |
187 | error = "not an SSH-1 RSA file"; | |
188 | ||
189 | end: | |
190 | if (fp) | |
191 | fclose(fp); | |
192 | if ((ret != 1) && errorstr) | |
193 | *errorstr = error; | |
194 | return ret; | |
195 | } | |
196 | ||
197 | /* | |
198 | * See whether an RSA key is encrypted. Return its comment field as | |
199 | * well. | |
200 | */ | |
201 | int rsakey_encrypted(const Filename *filename, char **comment) | |
202 | { | |
203 | FILE *fp; | |
204 | char buf[64]; | |
205 | ||
206 | fp = f_open(*filename, "rb", FALSE); | |
207 | if (!fp) | |
208 | return 0; /* doesn't even exist */ | |
209 | ||
210 | /* | |
211 | * Read the first line of the file and see if it's a v1 private | |
212 | * key file. | |
213 | */ | |
214 | if (fgets(buf, sizeof(buf), fp) && !strcmp(buf, rsa_signature)) { | |
215 | const char *dummy; | |
216 | /* | |
217 | * This routine will take care of calling fclose() for us. | |
218 | */ | |
219 | return loadrsakey_main(fp, NULL, FALSE, comment, NULL, &dummy); | |
220 | } | |
221 | fclose(fp); | |
222 | return 0; /* wasn't the right kind of file */ | |
223 | } | |
224 | ||
225 | /* | |
226 | * Return a malloc'ed chunk of memory containing the public blob of | |
227 | * an RSA key, as given in the agent protocol (modulus bits, | |
228 | * exponent, modulus). | |
229 | */ | |
230 | int rsakey_pubblob(const Filename *filename, void **blob, int *bloblen, | |
231 | char **commentptr, const char **errorstr) | |
232 | { | |
233 | FILE *fp; | |
234 | char buf[64]; | |
235 | struct RSAKey key; | |
236 | int ret; | |
237 | const char *error = NULL; | |
238 | ||
239 | /* Default return if we fail. */ | |
240 | *blob = NULL; | |
241 | *bloblen = 0; | |
242 | ret = 0; | |
243 | ||
244 | fp = f_open(*filename, "rb", FALSE); | |
245 | if (!fp) { | |
246 | error = "can't open file"; | |
247 | goto end; | |
248 | } | |
249 | ||
250 | /* | |
251 | * Read the first line of the file and see if it's a v1 private | |
252 | * key file. | |
253 | */ | |
254 | if (fgets(buf, sizeof(buf), fp) && !strcmp(buf, rsa_signature)) { | |
255 | memset(&key, 0, sizeof(key)); | |
256 | if (loadrsakey_main(fp, &key, TRUE, commentptr, NULL, &error)) { | |
257 | *blob = rsa_public_blob(&key, bloblen); | |
258 | freersakey(&key); | |
259 | ret = 1; | |
260 | fp = NULL; | |
261 | } | |
262 | } else { | |
263 | error = "not an SSH-1 RSA file"; | |
264 | } | |
265 | ||
266 | end: | |
267 | if (fp) | |
268 | fclose(fp); | |
269 | if ((ret != 1) && errorstr) | |
270 | *errorstr = error; | |
271 | return ret; | |
272 | } | |
273 | ||
274 | /* | |
275 | * Save an RSA key file. Return nonzero on success. | |
276 | */ | |
277 | int saversakey(const Filename *filename, struct RSAKey *key, char *passphrase) | |
278 | { | |
279 | unsigned char buf[16384]; | |
280 | unsigned char keybuf[16]; | |
281 | struct MD5Context md5c; | |
282 | unsigned char *p, *estart; | |
283 | FILE *fp; | |
284 | ||
285 | /* | |
286 | * Write the initial signature. | |
287 | */ | |
288 | p = buf; | |
289 | memcpy(p, rsa_signature, sizeof(rsa_signature)); | |
290 | p += sizeof(rsa_signature); | |
291 | ||
292 | /* | |
293 | * One byte giving encryption type, and one reserved (zero) | |
294 | * uint32. | |
295 | */ | |
296 | *p++ = (passphrase ? SSH_CIPHER_3DES : 0); | |
297 | PUT_32BIT(p, 0); | |
298 | p += 4; | |
299 | ||
300 | /* | |
301 | * An ordinary SSH-1 public key consists of: a uint32 | |
302 | * containing the bit count, then two bignums containing the | |
303 | * modulus and exponent respectively. | |
304 | */ | |
305 | PUT_32BIT(p, bignum_bitcount(key->modulus)); | |
306 | p += 4; | |
307 | p += ssh1_write_bignum(p, key->modulus); | |
308 | p += ssh1_write_bignum(p, key->exponent); | |
309 | ||
310 | /* | |
311 | * A string containing the comment field. | |
312 | */ | |
313 | if (key->comment) { | |
314 | PUT_32BIT(p, strlen(key->comment)); | |
315 | p += 4; | |
316 | memcpy(p, key->comment, strlen(key->comment)); | |
317 | p += strlen(key->comment); | |
318 | } else { | |
319 | PUT_32BIT(p, 0); | |
320 | p += 4; | |
321 | } | |
322 | ||
323 | /* | |
324 | * The encrypted portion starts here. | |
325 | */ | |
326 | estart = p; | |
327 | ||
328 | /* | |
329 | * Two bytes, then the same two bytes repeated. | |
330 | */ | |
331 | *p++ = random_byte(); | |
332 | *p++ = random_byte(); | |
333 | p[0] = p[-2]; | |
334 | p[1] = p[-1]; | |
335 | p += 2; | |
336 | ||
337 | /* | |
338 | * Four more bignums: the decryption exponent, then iqmp, then | |
339 | * q, then p. | |
340 | */ | |
341 | p += ssh1_write_bignum(p, key->private_exponent); | |
342 | p += ssh1_write_bignum(p, key->iqmp); | |
343 | p += ssh1_write_bignum(p, key->q); | |
344 | p += ssh1_write_bignum(p, key->p); | |
345 | ||
346 | /* | |
347 | * Now write zeros until the encrypted portion is a multiple of | |
348 | * 8 bytes. | |
349 | */ | |
350 | while ((p - estart) % 8) | |
351 | *p++ = '\0'; | |
352 | ||
353 | /* | |
354 | * Now encrypt the encrypted portion. | |
355 | */ | |
356 | if (passphrase) { | |
357 | MD5Init(&md5c); | |
358 | MD5Update(&md5c, (unsigned char *)passphrase, strlen(passphrase)); | |
359 | MD5Final(keybuf, &md5c); | |
360 | des3_encrypt_pubkey(keybuf, estart, p - estart); | |
361 | memset(keybuf, 0, sizeof(keybuf)); /* burn the evidence */ | |
362 | } | |
363 | ||
364 | /* | |
365 | * Done. Write the result to the file. | |
366 | */ | |
367 | fp = f_open(*filename, "wb", TRUE); | |
368 | if (fp) { | |
369 | int ret = (fwrite(buf, 1, p - buf, fp) == (size_t) (p - buf)); | |
370 | if (fclose(fp)) | |
371 | ret = 0; | |
372 | return ret; | |
373 | } else | |
374 | return 0; | |
375 | } | |
376 | ||
377 | /* ---------------------------------------------------------------------- | |
378 | * SSH-2 private key load/store functions. | |
379 | */ | |
380 | ||
381 | /* | |
382 | * PuTTY's own format for SSH-2 keys is as follows: | |
383 | * | |
384 | * The file is text. Lines are terminated by CRLF, although CR-only | |
385 | * and LF-only are tolerated on input. | |
386 | * | |
387 | * The first line says "PuTTY-User-Key-File-2: " plus the name of the | |
388 | * algorithm ("ssh-dss", "ssh-rsa" etc). | |
389 | * | |
390 | * The next line says "Encryption: " plus an encryption type. | |
391 | * Currently the only supported encryption types are "aes256-cbc" | |
392 | * and "none". | |
393 | * | |
394 | * The next line says "Comment: " plus the comment string. | |
395 | * | |
396 | * Next there is a line saying "Public-Lines: " plus a number N. | |
397 | * The following N lines contain a base64 encoding of the public | |
398 | * part of the key. This is encoded as the standard SSH-2 public key | |
399 | * blob (with no initial length): so for RSA, for example, it will | |
400 | * read | |
401 | * | |
402 | * string "ssh-rsa" | |
403 | * mpint exponent | |
404 | * mpint modulus | |
405 | * | |
406 | * Next, there is a line saying "Private-Lines: " plus a number N, | |
407 | * and then N lines containing the (potentially encrypted) private | |
408 | * part of the key. For the key type "ssh-rsa", this will be | |
409 | * composed of | |
410 | * | |
411 | * mpint private_exponent | |
412 | * mpint p (the larger of the two primes) | |
413 | * mpint q (the smaller prime) | |
414 | * mpint iqmp (the inverse of q modulo p) | |
415 | * data padding (to reach a multiple of the cipher block size) | |
416 | * | |
417 | * And for "ssh-dss", it will be composed of | |
418 | * | |
419 | * mpint x (the private key parameter) | |
420 | * [ string hash 20-byte hash of mpints p || q || g only in old format ] | |
421 | * | |
422 | * Finally, there is a line saying "Private-MAC: " plus a hex | |
423 | * representation of a HMAC-SHA-1 of: | |
424 | * | |
425 | * string name of algorithm ("ssh-dss", "ssh-rsa") | |
426 | * string encryption type | |
427 | * string comment | |
428 | * string public-blob | |
429 | * string private-plaintext (the plaintext version of the | |
430 | * private part, including the final | |
431 | * padding) | |
432 | * | |
433 | * The key to the MAC is itself a SHA-1 hash of: | |
434 | * | |
435 | * data "putty-private-key-file-mac-key" | |
436 | * data passphrase | |
437 | * | |
438 | * (An empty passphrase is used for unencrypted keys.) | |
439 | * | |
440 | * If the key is encrypted, the encryption key is derived from the | |
441 | * passphrase by means of a succession of SHA-1 hashes. Each hash | |
442 | * is the hash of: | |
443 | * | |
444 | * uint32 sequence-number | |
445 | * data passphrase | |
446 | * | |
447 | * where the sequence-number increases from zero. As many of these | |
448 | * hashes are used as necessary. | |
449 | * | |
450 | * For backwards compatibility with snapshots between 0.51 and | |
451 | * 0.52, we also support the older key file format, which begins | |
452 | * with "PuTTY-User-Key-File-1" (version number differs). In this | |
453 | * format the Private-MAC: field only covers the private-plaintext | |
454 | * field and nothing else (and without the 4-byte string length on | |
455 | * the front too). Moreover, the Private-MAC: field can be replaced | |
456 | * with a Private-Hash: field which is a plain SHA-1 hash instead of | |
457 | * an HMAC (this was generated for unencrypted keys). | |
458 | */ | |
459 | ||
460 | static int read_header(FILE * fp, char *header) | |
461 | { | |
462 | int len = 39; | |
463 | int c; | |
464 | ||
465 | while (len > 0) { | |
466 | c = fgetc(fp); | |
467 | if (c == '\n' || c == '\r' || c == EOF) | |
468 | return 0; /* failure */ | |
469 | if (c == ':') { | |
470 | c = fgetc(fp); | |
471 | if (c != ' ') | |
472 | return 0; | |
473 | *header = '\0'; | |
474 | return 1; /* success! */ | |
475 | } | |
476 | if (len == 0) | |
477 | return 0; /* failure */ | |
478 | *header++ = c; | |
479 | len--; | |
480 | } | |
481 | return 0; /* failure */ | |
482 | } | |
483 | ||
484 | static char *read_body(FILE * fp) | |
485 | { | |
486 | char *text; | |
487 | int len; | |
488 | int size; | |
489 | int c; | |
490 | ||
491 | size = 128; | |
492 | text = snewn(size, char); | |
493 | len = 0; | |
494 | text[len] = '\0'; | |
495 | ||
496 | while (1) { | |
497 | c = fgetc(fp); | |
498 | if (c == '\r' || c == '\n' || c == EOF) { | |
499 | if (c != EOF) { | |
500 | c = fgetc(fp); | |
501 | if (c != '\r' && c != '\n') | |
502 | ungetc(c, fp); | |
503 | } | |
504 | return text; | |
505 | } | |
506 | if (len + 1 >= size) { | |
507 | size += 128; | |
508 | text = sresize(text, size, char); | |
509 | } | |
510 | text[len++] = c; | |
511 | text[len] = '\0'; | |
512 | } | |
513 | } | |
514 | ||
515 | int base64_decode_atom(char *atom, unsigned char *out) | |
516 | { | |
517 | int vals[4]; | |
518 | int i, v, len; | |
519 | unsigned word; | |
520 | char c; | |
521 | ||
522 | for (i = 0; i < 4; i++) { | |
523 | c = atom[i]; | |
524 | if (c >= 'A' && c <= 'Z') | |
525 | v = c - 'A'; | |
526 | else if (c >= 'a' && c <= 'z') | |
527 | v = c - 'a' + 26; | |
528 | else if (c >= '0' && c <= '9') | |
529 | v = c - '0' + 52; | |
530 | else if (c == '+') | |
531 | v = 62; | |
532 | else if (c == '/') | |
533 | v = 63; | |
534 | else if (c == '=') | |
535 | v = -1; | |
536 | else | |
537 | return 0; /* invalid atom */ | |
538 | vals[i] = v; | |
539 | } | |
540 | ||
541 | if (vals[0] == -1 || vals[1] == -1) | |
542 | return 0; | |
543 | if (vals[2] == -1 && vals[3] != -1) | |
544 | return 0; | |
545 | ||
546 | if (vals[3] != -1) | |
547 | len = 3; | |
548 | else if (vals[2] != -1) | |
549 | len = 2; | |
550 | else | |
551 | len = 1; | |
552 | ||
553 | word = ((vals[0] << 18) | | |
554 | (vals[1] << 12) | ((vals[2] & 0x3F) << 6) | (vals[3] & 0x3F)); | |
555 | out[0] = (word >> 16) & 0xFF; | |
556 | if (len > 1) | |
557 | out[1] = (word >> 8) & 0xFF; | |
558 | if (len > 2) | |
559 | out[2] = word & 0xFF; | |
560 | return len; | |
561 | } | |
562 | ||
563 | static unsigned char *read_blob(FILE * fp, int nlines, int *bloblen) | |
564 | { | |
565 | unsigned char *blob; | |
566 | char *line; | |
567 | int linelen, len; | |
568 | int i, j, k; | |
569 | ||
570 | /* We expect at most 64 base64 characters, ie 48 real bytes, per line. */ | |
571 | blob = snewn(48 * nlines, unsigned char); | |
572 | len = 0; | |
573 | for (i = 0; i < nlines; i++) { | |
574 | line = read_body(fp); | |
575 | if (!line) { | |
576 | sfree(blob); | |
577 | return NULL; | |
578 | } | |
579 | linelen = strlen(line); | |
580 | if (linelen % 4 != 0 || linelen > 64) { | |
581 | sfree(blob); | |
582 | sfree(line); | |
583 | return NULL; | |
584 | } | |
585 | for (j = 0; j < linelen; j += 4) { | |
586 | k = base64_decode_atom(line + j, blob + len); | |
587 | if (!k) { | |
588 | sfree(line); | |
589 | sfree(blob); | |
590 | return NULL; | |
591 | } | |
592 | len += k; | |
593 | } | |
594 | sfree(line); | |
595 | } | |
596 | *bloblen = len; | |
597 | return blob; | |
598 | } | |
599 | ||
600 | /* | |
601 | * Magic error return value for when the passphrase is wrong. | |
602 | */ | |
603 | struct ssh2_userkey ssh2_wrong_passphrase = { | |
604 | NULL, NULL, NULL | |
605 | }; | |
606 | ||
607 | const struct ssh_signkey *find_pubkey_alg(const char *name) | |
608 | { | |
609 | if (!strcmp(name, "ssh-rsa")) | |
610 | return &ssh_rsa; | |
611 | else if (!strcmp(name, "ssh-dss")) | |
612 | return &ssh_dss; | |
613 | else | |
614 | return NULL; | |
615 | } | |
616 | ||
617 | struct ssh2_userkey *ssh2_load_userkey(const Filename *filename, | |
618 | char *passphrase, const char **errorstr) | |
619 | { | |
620 | FILE *fp; | |
621 | char header[40], *b, *encryption, *comment, *mac; | |
622 | const struct ssh_signkey *alg; | |
623 | struct ssh2_userkey *ret; | |
624 | int cipher, cipherblk; | |
625 | unsigned char *public_blob, *private_blob; | |
626 | int public_blob_len, private_blob_len; | |
627 | int i, is_mac, old_fmt; | |
628 | int passlen = passphrase ? strlen(passphrase) : 0; | |
629 | const char *error = NULL; | |
630 | ||
631 | ret = NULL; /* return NULL for most errors */ | |
632 | encryption = comment = mac = NULL; | |
633 | public_blob = private_blob = NULL; | |
634 | ||
635 | fp = f_open(*filename, "rb", FALSE); | |
636 | if (!fp) { | |
637 | error = "can't open file"; | |
638 | goto error; | |
639 | } | |
640 | ||
641 | /* Read the first header line which contains the key type. */ | |
642 | if (!read_header(fp, header)) | |
643 | goto error; | |
644 | if (0 == strcmp(header, "PuTTY-User-Key-File-2")) { | |
645 | old_fmt = 0; | |
646 | } else if (0 == strcmp(header, "PuTTY-User-Key-File-1")) { | |
647 | /* this is an old key file; warn and then continue */ | |
648 | old_keyfile_warning(); | |
649 | old_fmt = 1; | |
650 | } else { | |
651 | error = "not a PuTTY SSH-2 private key"; | |
652 | goto error; | |
653 | } | |
654 | error = "file format error"; | |
655 | if ((b = read_body(fp)) == NULL) | |
656 | goto error; | |
657 | /* Select key algorithm structure. */ | |
658 | alg = find_pubkey_alg(b); | |
659 | if (!alg) { | |
660 | sfree(b); | |
661 | goto error; | |
662 | } | |
663 | sfree(b); | |
664 | ||
665 | /* Read the Encryption header line. */ | |
666 | if (!read_header(fp, header) || 0 != strcmp(header, "Encryption")) | |
667 | goto error; | |
668 | if ((encryption = read_body(fp)) == NULL) | |
669 | goto error; | |
670 | if (!strcmp(encryption, "aes256-cbc")) { | |
671 | cipher = 1; | |
672 | cipherblk = 16; | |
673 | } else if (!strcmp(encryption, "none")) { | |
674 | cipher = 0; | |
675 | cipherblk = 1; | |
676 | } else { | |
677 | sfree(encryption); | |
678 | goto error; | |
679 | } | |
680 | ||
681 | /* Read the Comment header line. */ | |
682 | if (!read_header(fp, header) || 0 != strcmp(header, "Comment")) | |
683 | goto error; | |
684 | if ((comment = read_body(fp)) == NULL) | |
685 | goto error; | |
686 | ||
687 | /* Read the Public-Lines header line and the public blob. */ | |
688 | if (!read_header(fp, header) || 0 != strcmp(header, "Public-Lines")) | |
689 | goto error; | |
690 | if ((b = read_body(fp)) == NULL) | |
691 | goto error; | |
692 | i = atoi(b); | |
693 | sfree(b); | |
694 | if ((public_blob = read_blob(fp, i, &public_blob_len)) == NULL) | |
695 | goto error; | |
696 | ||
697 | /* Read the Private-Lines header line and the Private blob. */ | |
698 | if (!read_header(fp, header) || 0 != strcmp(header, "Private-Lines")) | |
699 | goto error; | |
700 | if ((b = read_body(fp)) == NULL) | |
701 | goto error; | |
702 | i = atoi(b); | |
703 | sfree(b); | |
704 | if ((private_blob = read_blob(fp, i, &private_blob_len)) == NULL) | |
705 | goto error; | |
706 | ||
707 | /* Read the Private-MAC or Private-Hash header line. */ | |
708 | if (!read_header(fp, header)) | |
709 | goto error; | |
710 | if (0 == strcmp(header, "Private-MAC")) { | |
711 | if ((mac = read_body(fp)) == NULL) | |
712 | goto error; | |
713 | is_mac = 1; | |
714 | } else if (0 == strcmp(header, "Private-Hash") && old_fmt) { | |
715 | if ((mac = read_body(fp)) == NULL) | |
716 | goto error; | |
717 | is_mac = 0; | |
718 | } else | |
719 | goto error; | |
720 | ||
721 | fclose(fp); | |
722 | fp = NULL; | |
723 | ||
724 | /* | |
725 | * Decrypt the private blob. | |
726 | */ | |
727 | if (cipher) { | |
728 | unsigned char key[40]; | |
729 | SHA_State s; | |
730 | ||
731 | if (!passphrase) | |
732 | goto error; | |
733 | if (private_blob_len % cipherblk) | |
734 | goto error; | |
735 | ||
736 | SHA_Init(&s); | |
737 | SHA_Bytes(&s, "\0\0\0\0", 4); | |
738 | SHA_Bytes(&s, passphrase, passlen); | |
739 | SHA_Final(&s, key + 0); | |
740 | SHA_Init(&s); | |
741 | SHA_Bytes(&s, "\0\0\0\1", 4); | |
742 | SHA_Bytes(&s, passphrase, passlen); | |
743 | SHA_Final(&s, key + 20); | |
744 | aes256_decrypt_pubkey(key, private_blob, private_blob_len); | |
745 | } | |
746 | ||
747 | /* | |
748 | * Verify the MAC. | |
749 | */ | |
750 | { | |
751 | char realmac[41]; | |
752 | unsigned char binary[20]; | |
753 | unsigned char *macdata; | |
754 | int maclen; | |
755 | int free_macdata; | |
756 | ||
757 | if (old_fmt) { | |
758 | /* MAC (or hash) only covers the private blob. */ | |
759 | macdata = private_blob; | |
760 | maclen = private_blob_len; | |
761 | free_macdata = 0; | |
762 | } else { | |
763 | unsigned char *p; | |
764 | int namelen = strlen(alg->name); | |
765 | int enclen = strlen(encryption); | |
766 | int commlen = strlen(comment); | |
767 | maclen = (4 + namelen + | |
768 | 4 + enclen + | |
769 | 4 + commlen + | |
770 | 4 + public_blob_len + | |
771 | 4 + private_blob_len); | |
772 | macdata = snewn(maclen, unsigned char); | |
773 | p = macdata; | |
774 | #define DO_STR(s,len) PUT_32BIT(p,(len));memcpy(p+4,(s),(len));p+=4+(len) | |
775 | DO_STR(alg->name, namelen); | |
776 | DO_STR(encryption, enclen); | |
777 | DO_STR(comment, commlen); | |
778 | DO_STR(public_blob, public_blob_len); | |
779 | DO_STR(private_blob, private_blob_len); | |
780 | ||
781 | free_macdata = 1; | |
782 | } | |
783 | ||
784 | if (is_mac) { | |
785 | SHA_State s; | |
786 | unsigned char mackey[20]; | |
787 | char header[] = "putty-private-key-file-mac-key"; | |
788 | ||
789 | SHA_Init(&s); | |
790 | SHA_Bytes(&s, header, sizeof(header)-1); | |
791 | if (cipher && passphrase) | |
792 | SHA_Bytes(&s, passphrase, passlen); | |
793 | SHA_Final(&s, mackey); | |
794 | ||
795 | hmac_sha1_simple(mackey, 20, macdata, maclen, binary); | |
796 | ||
797 | memset(mackey, 0, sizeof(mackey)); | |
798 | memset(&s, 0, sizeof(s)); | |
799 | } else { | |
800 | SHA_Simple(macdata, maclen, binary); | |
801 | } | |
802 | ||
803 | if (free_macdata) { | |
804 | memset(macdata, 0, maclen); | |
805 | sfree(macdata); | |
806 | } | |
807 | ||
808 | for (i = 0; i < 20; i++) | |
809 | sprintf(realmac + 2 * i, "%02x", binary[i]); | |
810 | ||
811 | if (strcmp(mac, realmac)) { | |
812 | /* An incorrect MAC is an unconditional Error if the key is | |
813 | * unencrypted. Otherwise, it means Wrong Passphrase. */ | |
814 | if (cipher) { | |
815 | error = "wrong passphrase"; | |
816 | ret = SSH2_WRONG_PASSPHRASE; | |
817 | } else { | |
818 | error = "MAC failed"; | |
819 | ret = NULL; | |
820 | } | |
821 | goto error; | |
822 | } | |
823 | } | |
824 | sfree(mac); | |
825 | ||
826 | /* | |
827 | * Create and return the key. | |
828 | */ | |
829 | ret = snew(struct ssh2_userkey); | |
830 | ret->alg = alg; | |
831 | ret->comment = comment; | |
832 | ret->data = alg->createkey(public_blob, public_blob_len, | |
833 | private_blob, private_blob_len); | |
834 | if (!ret->data) { | |
835 | sfree(ret->comment); | |
836 | sfree(ret); | |
837 | ret = NULL; | |
838 | error = "createkey failed"; | |
839 | goto error; | |
840 | } | |
841 | sfree(public_blob); | |
842 | sfree(private_blob); | |
843 | sfree(encryption); | |
844 | if (errorstr) | |
845 | *errorstr = NULL; | |
846 | return ret; | |
847 | ||
848 | /* | |
849 | * Error processing. | |
850 | */ | |
851 | error: | |
852 | if (fp) | |
853 | fclose(fp); | |
854 | if (comment) | |
855 | sfree(comment); | |
856 | if (encryption) | |
857 | sfree(encryption); | |
858 | if (mac) | |
859 | sfree(mac); | |
860 | if (public_blob) | |
861 | sfree(public_blob); | |
862 | if (private_blob) | |
863 | sfree(private_blob); | |
864 | if (errorstr) | |
865 | *errorstr = error; | |
866 | return ret; | |
867 | } | |
868 | ||
869 | unsigned char *ssh2_userkey_loadpub(const Filename *filename, char **algorithm, | |
870 | int *pub_blob_len, char **commentptr, | |
871 | const char **errorstr) | |
872 | { | |
873 | FILE *fp; | |
874 | char header[40], *b; | |
875 | const struct ssh_signkey *alg; | |
876 | unsigned char *public_blob; | |
877 | int public_blob_len; | |
878 | int i; | |
879 | const char *error = NULL; | |
880 | char *comment; | |
881 | ||
882 | public_blob = NULL; | |
883 | ||
884 | fp = f_open(*filename, "rb", FALSE); | |
885 | if (!fp) { | |
886 | error = "can't open file"; | |
887 | goto error; | |
888 | } | |
889 | ||
890 | /* Read the first header line which contains the key type. */ | |
891 | if (!read_header(fp, header) | |
892 | || (0 != strcmp(header, "PuTTY-User-Key-File-2") && | |
893 | 0 != strcmp(header, "PuTTY-User-Key-File-1"))) { | |
894 | error = "not a PuTTY SSH-2 private key"; | |
895 | goto error; | |
896 | } | |
897 | error = "file format error"; | |
898 | if ((b = read_body(fp)) == NULL) | |
899 | goto error; | |
900 | /* Select key algorithm structure. */ | |
901 | alg = find_pubkey_alg(b); | |
902 | if (!alg) { | |
903 | sfree(b); | |
904 | goto error; | |
905 | } | |
906 | sfree(b); | |
907 | ||
908 | /* Read the Encryption header line. */ | |
909 | if (!read_header(fp, header) || 0 != strcmp(header, "Encryption")) | |
910 | goto error; | |
911 | if ((b = read_body(fp)) == NULL) | |
912 | goto error; | |
913 | sfree(b); /* we don't care */ | |
914 | ||
915 | /* Read the Comment header line. */ | |
916 | if (!read_header(fp, header) || 0 != strcmp(header, "Comment")) | |
917 | goto error; | |
918 | if ((comment = read_body(fp)) == NULL) | |
919 | goto error; | |
920 | ||
921 | if (commentptr) | |
922 | *commentptr = comment; | |
923 | else | |
924 | sfree(comment); | |
925 | ||
926 | /* Read the Public-Lines header line and the public blob. */ | |
927 | if (!read_header(fp, header) || 0 != strcmp(header, "Public-Lines")) | |
928 | goto error; | |
929 | if ((b = read_body(fp)) == NULL) | |
930 | goto error; | |
931 | i = atoi(b); | |
932 | sfree(b); | |
933 | if ((public_blob = read_blob(fp, i, &public_blob_len)) == NULL) | |
934 | goto error; | |
935 | ||
936 | fclose(fp); | |
937 | if (pub_blob_len) | |
938 | *pub_blob_len = public_blob_len; | |
939 | if (algorithm) | |
940 | *algorithm = alg->name; | |
941 | return public_blob; | |
942 | ||
943 | /* | |
944 | * Error processing. | |
945 | */ | |
946 | error: | |
947 | if (fp) | |
948 | fclose(fp); | |
949 | if (public_blob) | |
950 | sfree(public_blob); | |
951 | if (errorstr) | |
952 | *errorstr = error; | |
953 | return NULL; | |
954 | } | |
955 | ||
956 | int ssh2_userkey_encrypted(const Filename *filename, char **commentptr) | |
957 | { | |
958 | FILE *fp; | |
959 | char header[40], *b, *comment; | |
960 | int ret; | |
961 | ||
962 | if (commentptr) | |
963 | *commentptr = NULL; | |
964 | ||
965 | fp = f_open(*filename, "rb", FALSE); | |
966 | if (!fp) | |
967 | return 0; | |
968 | if (!read_header(fp, header) | |
969 | || (0 != strcmp(header, "PuTTY-User-Key-File-2") && | |
970 | 0 != strcmp(header, "PuTTY-User-Key-File-1"))) { | |
971 | fclose(fp); | |
972 | return 0; | |
973 | } | |
974 | if ((b = read_body(fp)) == NULL) { | |
975 | fclose(fp); | |
976 | return 0; | |
977 | } | |
978 | sfree(b); /* we don't care about key type here */ | |
979 | /* Read the Encryption header line. */ | |
980 | if (!read_header(fp, header) || 0 != strcmp(header, "Encryption")) { | |
981 | fclose(fp); | |
982 | return 0; | |
983 | } | |
984 | if ((b = read_body(fp)) == NULL) { | |
985 | fclose(fp); | |
986 | return 0; | |
987 | } | |
988 | ||
989 | /* Read the Comment header line. */ | |
990 | if (!read_header(fp, header) || 0 != strcmp(header, "Comment")) { | |
991 | fclose(fp); | |
992 | sfree(b); | |
993 | return 1; | |
994 | } | |
995 | if ((comment = read_body(fp)) == NULL) { | |
996 | fclose(fp); | |
997 | sfree(b); | |
998 | return 1; | |
999 | } | |
1000 | ||
1001 | if (commentptr) | |
1002 | *commentptr = comment; | |
1003 | ||
1004 | fclose(fp); | |
1005 | if (!strcmp(b, "aes256-cbc")) | |
1006 | ret = 1; | |
1007 | else | |
1008 | ret = 0; | |
1009 | sfree(b); | |
1010 | return ret; | |
1011 | } | |
1012 | ||
1013 | int base64_lines(int datalen) | |
1014 | { | |
1015 | /* When encoding, we use 64 chars/line, which equals 48 real chars. */ | |
1016 | return (datalen + 47) / 48; | |
1017 | } | |
1018 | ||
1019 | void base64_encode(FILE * fp, unsigned char *data, int datalen, int cpl) | |
1020 | { | |
1021 | int linelen = 0; | |
1022 | char out[4]; | |
1023 | int n, i; | |
1024 | ||
1025 | while (datalen > 0) { | |
1026 | n = (datalen < 3 ? datalen : 3); | |
1027 | base64_encode_atom(data, n, out); | |
1028 | data += n; | |
1029 | datalen -= n; | |
1030 | for (i = 0; i < 4; i++) { | |
1031 | if (linelen >= cpl) { | |
1032 | linelen = 0; | |
1033 | fputc('\n', fp); | |
1034 | } | |
1035 | fputc(out[i], fp); | |
1036 | linelen++; | |
1037 | } | |
1038 | } | |
1039 | fputc('\n', fp); | |
1040 | } | |
1041 | ||
1042 | int ssh2_save_userkey(const Filename *filename, struct ssh2_userkey *key, | |
1043 | char *passphrase) | |
1044 | { | |
1045 | FILE *fp; | |
1046 | unsigned char *pub_blob, *priv_blob, *priv_blob_encrypted; | |
1047 | int pub_blob_len, priv_blob_len, priv_encrypted_len; | |
1048 | int passlen; | |
1049 | int cipherblk; | |
1050 | int i; | |
1051 | char *cipherstr; | |
1052 | unsigned char priv_mac[20]; | |
1053 | ||
1054 | /* | |
1055 | * Fetch the key component blobs. | |
1056 | */ | |
1057 | pub_blob = key->alg->public_blob(key->data, &pub_blob_len); | |
1058 | priv_blob = key->alg->private_blob(key->data, &priv_blob_len); | |
1059 | if (!pub_blob || !priv_blob) { | |
1060 | sfree(pub_blob); | |
1061 | sfree(priv_blob); | |
1062 | return 0; | |
1063 | } | |
1064 | ||
1065 | /* | |
1066 | * Determine encryption details, and encrypt the private blob. | |
1067 | */ | |
1068 | if (passphrase) { | |
1069 | cipherstr = "aes256-cbc"; | |
1070 | cipherblk = 16; | |
1071 | } else { | |
1072 | cipherstr = "none"; | |
1073 | cipherblk = 1; | |
1074 | } | |
1075 | priv_encrypted_len = priv_blob_len + cipherblk - 1; | |
1076 | priv_encrypted_len -= priv_encrypted_len % cipherblk; | |
1077 | priv_blob_encrypted = snewn(priv_encrypted_len, unsigned char); | |
1078 | memset(priv_blob_encrypted, 0, priv_encrypted_len); | |
1079 | memcpy(priv_blob_encrypted, priv_blob, priv_blob_len); | |
1080 | /* Create padding based on the SHA hash of the unpadded blob. This prevents | |
1081 | * too easy a known-plaintext attack on the last block. */ | |
1082 | SHA_Simple(priv_blob, priv_blob_len, priv_mac); | |
1083 | assert(priv_encrypted_len - priv_blob_len < 20); | |
1084 | memcpy(priv_blob_encrypted + priv_blob_len, priv_mac, | |
1085 | priv_encrypted_len - priv_blob_len); | |
1086 | ||
1087 | /* Now create the MAC. */ | |
1088 | { | |
1089 | unsigned char *macdata; | |
1090 | int maclen; | |
1091 | unsigned char *p; | |
1092 | int namelen = strlen(key->alg->name); | |
1093 | int enclen = strlen(cipherstr); | |
1094 | int commlen = strlen(key->comment); | |
1095 | SHA_State s; | |
1096 | unsigned char mackey[20]; | |
1097 | char header[] = "putty-private-key-file-mac-key"; | |
1098 | ||
1099 | maclen = (4 + namelen + | |
1100 | 4 + enclen + | |
1101 | 4 + commlen + | |
1102 | 4 + pub_blob_len + | |
1103 | 4 + priv_encrypted_len); | |
1104 | macdata = snewn(maclen, unsigned char); | |
1105 | p = macdata; | |
1106 | #define DO_STR(s,len) PUT_32BIT(p,(len));memcpy(p+4,(s),(len));p+=4+(len) | |
1107 | DO_STR(key->alg->name, namelen); | |
1108 | DO_STR(cipherstr, enclen); | |
1109 | DO_STR(key->comment, commlen); | |
1110 | DO_STR(pub_blob, pub_blob_len); | |
1111 | DO_STR(priv_blob_encrypted, priv_encrypted_len); | |
1112 | ||
1113 | SHA_Init(&s); | |
1114 | SHA_Bytes(&s, header, sizeof(header)-1); | |
1115 | if (passphrase) | |
1116 | SHA_Bytes(&s, passphrase, strlen(passphrase)); | |
1117 | SHA_Final(&s, mackey); | |
1118 | hmac_sha1_simple(mackey, 20, macdata, maclen, priv_mac); | |
1119 | memset(macdata, 0, maclen); | |
1120 | sfree(macdata); | |
1121 | memset(mackey, 0, sizeof(mackey)); | |
1122 | memset(&s, 0, sizeof(s)); | |
1123 | } | |
1124 | ||
1125 | if (passphrase) { | |
1126 | unsigned char key[40]; | |
1127 | SHA_State s; | |
1128 | ||
1129 | passlen = strlen(passphrase); | |
1130 | ||
1131 | SHA_Init(&s); | |
1132 | SHA_Bytes(&s, "\0\0\0\0", 4); | |
1133 | SHA_Bytes(&s, passphrase, passlen); | |
1134 | SHA_Final(&s, key + 0); | |
1135 | SHA_Init(&s); | |
1136 | SHA_Bytes(&s, "\0\0\0\1", 4); | |
1137 | SHA_Bytes(&s, passphrase, passlen); | |
1138 | SHA_Final(&s, key + 20); | |
1139 | aes256_encrypt_pubkey(key, priv_blob_encrypted, | |
1140 | priv_encrypted_len); | |
1141 | ||
1142 | memset(key, 0, sizeof(key)); | |
1143 | memset(&s, 0, sizeof(s)); | |
1144 | } | |
1145 | ||
1146 | fp = f_open(*filename, "w", TRUE); | |
1147 | if (!fp) | |
1148 | return 0; | |
1149 | fprintf(fp, "PuTTY-User-Key-File-2: %s\n", key->alg->name); | |
1150 | fprintf(fp, "Encryption: %s\n", cipherstr); | |
1151 | fprintf(fp, "Comment: %s\n", key->comment); | |
1152 | fprintf(fp, "Public-Lines: %d\n", base64_lines(pub_blob_len)); | |
1153 | base64_encode(fp, pub_blob, pub_blob_len, 64); | |
1154 | fprintf(fp, "Private-Lines: %d\n", base64_lines(priv_encrypted_len)); | |
1155 | base64_encode(fp, priv_blob_encrypted, priv_encrypted_len, 64); | |
1156 | fprintf(fp, "Private-MAC: "); | |
1157 | for (i = 0; i < 20; i++) | |
1158 | fprintf(fp, "%02x", priv_mac[i]); | |
1159 | fprintf(fp, "\n"); | |
1160 | fclose(fp); | |
1161 | ||
1162 | sfree(pub_blob); | |
1163 | memset(priv_blob, 0, priv_blob_len); | |
1164 | sfree(priv_blob); | |
1165 | sfree(priv_blob_encrypted); | |
1166 | return 1; | |
1167 | } | |
1168 | ||
1169 | /* ---------------------------------------------------------------------- | |
1170 | * A function to determine the type of a private key file. Returns | |
1171 | * 0 on failure, 1 or 2 on success. | |
1172 | */ | |
1173 | int key_type(const Filename *filename) | |
1174 | { | |
1175 | FILE *fp; | |
1176 | char buf[32]; | |
1177 | const char putty2_sig[] = "PuTTY-User-Key-File-"; | |
1178 | const char sshcom_sig[] = "---- BEGIN SSH2 ENCRYPTED PRIVAT"; | |
1179 | const char openssh_sig[] = "-----BEGIN "; | |
1180 | int i; | |
1181 | ||
1182 | fp = f_open(*filename, "r", FALSE); | |
1183 | if (!fp) | |
1184 | return SSH_KEYTYPE_UNOPENABLE; | |
1185 | i = fread(buf, 1, sizeof(buf), fp); | |
1186 | fclose(fp); | |
1187 | if (i < 0) | |
1188 | return SSH_KEYTYPE_UNOPENABLE; | |
1189 | if (i < 32) | |
1190 | return SSH_KEYTYPE_UNKNOWN; | |
1191 | if (!memcmp(buf, rsa_signature, sizeof(rsa_signature)-1)) | |
1192 | return SSH_KEYTYPE_SSH1; | |
1193 | if (!memcmp(buf, putty2_sig, sizeof(putty2_sig)-1)) | |
1194 | return SSH_KEYTYPE_SSH2; | |
1195 | if (!memcmp(buf, openssh_sig, sizeof(openssh_sig)-1)) | |
1196 | return SSH_KEYTYPE_OPENSSH; | |
1197 | if (!memcmp(buf, sshcom_sig, sizeof(sshcom_sig)-1)) | |
1198 | return SSH_KEYTYPE_SSHCOM; | |
1199 | return SSH_KEYTYPE_UNKNOWN; /* unrecognised or EOF */ | |
1200 | } | |
1201 | ||
1202 | /* | |
1203 | * Convert the type word to a string, for `wrong type' error | |
1204 | * messages. | |
1205 | */ | |
1206 | char *key_type_to_str(int type) | |
1207 | { | |
1208 | switch (type) { | |
1209 | case SSH_KEYTYPE_UNOPENABLE: return "unable to open file"; break; | |
1210 | case SSH_KEYTYPE_UNKNOWN: return "not a private key"; break; | |
1211 | case SSH_KEYTYPE_SSH1: return "SSH-1 private key"; break; | |
1212 | case SSH_KEYTYPE_SSH2: return "PuTTY SSH-2 private key"; break; | |
1213 | case SSH_KEYTYPE_OPENSSH: return "OpenSSH SSH-2 private key"; break; | |
1214 | case SSH_KEYTYPE_SSHCOM: return "ssh.com SSH-2 private key"; break; | |
1215 | default: return "INTERNAL ERROR"; break; | |
1216 | } | |
1217 | } |