| blob | d91c1eee32ea575fde3952716a79cb079c98e4f1 |
1 /*\r
2 * Generic SSH public-key handling operations. In particular,\r
3 * reading of SSH public-key files, and also the generic `sign'\r
4 * operation for SSH-2 (which checks the type of the key and\r
5 * dispatches to the appropriate key-type specific function).\r
6 */\r
7 \r
8 #include <stdio.h>\r
9 #include <stdlib.h>\r
10 #include <assert.h>\r
11 \r
12 #include "putty.h"\r
13 #include "ssh.h"\r
14 #include "misc.h"\r
15 \r
16 #define rsa_signature "SSH PRIVATE KEY FILE FORMAT 1.1\n"\r
17 \r
18 #define BASE64_TOINT(x) ( (x)-'A'<26 ? (x)-'A'+0 :\\r
19 (x)-'a'<26 ? (x)-'a'+26 :\\r
20 (x)-'0'<10 ? (x)-'0'+52 :\\r
21 (x)=='+' ? 62 : \\r
22 (x)=='/' ? 63 : 0 )\r
23 \r
24 static int loadrsakey_main(FILE * fp, struct RSAKey *key, int pub_only,\r
25 char **commentptr, char *passphrase,\r
26 const char **error)\r
27 {\r
28 unsigned char buf[16384];\r
29 unsigned char keybuf[16];\r
30 int len;\r
31 int i, j, ciphertype;\r
32 int ret = 0;\r
33 struct MD5Context md5c;\r
34 char *comment;\r
35 \r
36 *error = NULL;\r
37 \r
38 /* Slurp the whole file (minus the header) into a buffer. */\r
39 len = fread(buf, 1, sizeof(buf), fp);\r
40 fclose(fp);\r
41 if (len < 0 || len == sizeof(buf)) {\r
42 *error = "error reading file";\r
43 goto end; /* file too big or not read */\r
44 }\r
45 \r
46 i = 0;\r
47 *error = "file format error";\r
48 \r
49 /*\r
50 * A zero byte. (The signature includes a terminating NUL.)\r
51 */\r
52 if (len - i < 1 || buf[i] != 0)\r
53 goto end;\r
54 i++;\r
55 \r
56 /* One byte giving encryption type, and one reserved uint32. */\r
57 if (len - i < 1)\r
58 goto end;\r
59 ciphertype = buf[i];\r
60 if (ciphertype != 0 && ciphertype != SSH_CIPHER_3DES)\r
61 goto end;\r
62 i++;\r
63 if (len - i < 4)\r
64 goto end; /* reserved field not present */\r
65 if (buf[i] != 0 || buf[i + 1] != 0 || buf[i + 2] != 0\r
66 || buf[i + 3] != 0) goto end; /* reserved field nonzero, panic! */\r
67 i += 4;\r
68 \r
69 /* Now the serious stuff. An ordinary SSH-1 public key. */\r
70 j = makekey(buf + i, len - i, key, NULL, 1);\r
71 if (j < 0)\r
72 goto end; /* overran */\r
73 i += j;\r
74 \r
75 /* Next, the comment field. */\r
76 j = toint(GET_32BIT(buf + i));\r
77 i += 4;\r
78 if (j < 0 || len - i < j)\r
79 goto end;\r
80 comment = snewn(j + 1, char);\r
81 if (comment) {\r
82 memcpy(comment, buf + i, j);\r
83 comment[j] = '\0';\r
84 }\r
85 i += j;\r
86 if (commentptr)\r
87 *commentptr = dupstr(comment);\r
88 if (key)\r
89 key->comment = comment;\r
90 else\r
91 sfree(comment);\r
92 \r
93 if (pub_only) {\r
94 ret = 1;\r
95 goto end;\r
96 }\r
97 \r
98 if (!key) {\r
99 ret = ciphertype != 0;\r
100 *error = NULL;\r
101 goto end;\r
102 }\r
103 \r
104 /*\r
105 * Decrypt remainder of buffer.\r
106 */\r
107 if (ciphertype) {\r
108 MD5Init(&md5c);\r
109 MD5Update(&md5c, (unsigned char *)passphrase, strlen(passphrase));\r
110 MD5Final(keybuf, &md5c);\r
111 des3_decrypt_pubkey(keybuf, buf + i, (len - i + 7) & ~7);\r
112 smemclr(keybuf, sizeof(keybuf)); /* burn the evidence */\r
113 }\r
114 \r
115 /*\r
116 * We are now in the secret part of the key. The first four\r
117 * bytes should be of the form a, b, a, b.\r
118 */\r
119 if (len - i < 4)\r
120 goto end;\r
121 if (buf[i] != buf[i + 2] || buf[i + 1] != buf[i + 3]) {\r
122 *error = "wrong passphrase";\r
123 ret = -1;\r
124 goto end;\r
125 }\r
126 i += 4;\r
127 \r
128 /*\r
129 * After that, we have one further bignum which is our\r
130 * decryption exponent, and then the three auxiliary values\r
131 * (iqmp, q, p).\r
132 */\r
133 j = makeprivate(buf + i, len - i, key);\r
134 if (j < 0) goto end;\r
135 i += j;\r
136 j = ssh1_read_bignum(buf + i, len - i, &key->iqmp);\r
137 if (j < 0) goto end;\r
138 i += j;\r
139 j = ssh1_read_bignum(buf + i, len - i, &key->q);\r
140 if (j < 0) goto end;\r
141 i += j;\r
142 j = ssh1_read_bignum(buf + i, len - i, &key->p);\r
143 if (j < 0) goto end;\r
144 i += j;\r
145 \r
146 if (!rsa_verify(key)) {\r
147 *error = "rsa_verify failed";\r
148 freersakey(key);\r
149 ret = 0;\r
150 } else\r
151 ret = 1;\r
152 \r
153 end:\r
154 smemclr(buf, sizeof(buf)); /* burn the evidence */\r
155 return ret;\r
156 }\r
157 \r
158 int loadrsakey(const Filename *filename, struct RSAKey *key, char *passphrase,\r
159 const char **errorstr)\r
160 {\r
161 FILE *fp;\r
162 char buf[64];\r
163 int ret = 0;\r
164 const char *error = NULL;\r
165 \r
166 fp = f_open(filename, "rb", FALSE);\r
167 if (!fp) {\r
168 error = "can't open file";\r
169 goto end;\r
170 }\r
171 \r
172 /*\r
173 * Read the first line of the file and see if it's a v1 private\r
174 * key file.\r
175 */\r
176 if (fgets(buf, sizeof(buf), fp) && !strcmp(buf, rsa_signature)) {\r
177 /*\r
178 * This routine will take care of calling fclose() for us.\r
179 */\r
180 ret = loadrsakey_main(fp, key, FALSE, NULL, passphrase, &error);\r
181 fp = NULL;\r
182 goto end;\r
183 }\r
184 \r
185 /*\r
186 * Otherwise, we have nothing. Return empty-handed.\r
187 */\r
188 error = "not an SSH-1 RSA file";\r
189 \r
190 end:\r
191 if (fp)\r
192 fclose(fp);\r
193 if ((ret != 1) && errorstr)\r
194 *errorstr = error;\r
195 return ret;\r
196 }\r
197 \r
198 /*\r
199 * See whether an RSA key is encrypted. Return its comment field as\r
200 * well.\r
201 */\r
202 int rsakey_encrypted(const Filename *filename, char **comment)\r
203 {\r
204 FILE *fp;\r
205 char buf[64];\r
206 \r
207 fp = f_open(filename, "rb", FALSE);\r
208 if (!fp)\r
209 return 0; /* doesn't even exist */\r
210 \r
211 /*\r
212 * Read the first line of the file and see if it's a v1 private\r
213 * key file.\r
214 */\r
215 if (fgets(buf, sizeof(buf), fp) && !strcmp(buf, rsa_signature)) {\r
216 const char *dummy;\r
217 /*\r
218 * This routine will take care of calling fclose() for us.\r
219 */\r
220 return loadrsakey_main(fp, NULL, FALSE, comment, NULL, &dummy);\r
221 }\r
222 fclose(fp);\r
223 return 0; /* wasn't the right kind of file */\r
224 }\r
225 \r
226 /*\r
227 * Return a malloc'ed chunk of memory containing the public blob of\r
228 * an RSA key, as given in the agent protocol (modulus bits,\r
229 * exponent, modulus).\r
230 */\r
231 int rsakey_pubblob(const Filename *filename, void **blob, int *bloblen,\r
232 char **commentptr, const char **errorstr)\r
233 {\r
234 FILE *fp;\r
235 char buf[64];\r
236 struct RSAKey key;\r
237 int ret;\r
238 const char *error = NULL;\r
239 \r
240 /* Default return if we fail. */\r
241 *blob = NULL;\r
242 *bloblen = 0;\r
243 ret = 0;\r
244 \r
245 fp = f_open(filename, "rb", FALSE);\r
246 if (!fp) {\r
247 error = "can't open file";\r
248 goto end;\r
249 }\r
250 \r
251 /*\r
252 * Read the first line of the file and see if it's a v1 private\r
253 * key file.\r
254 */\r
255 if (fgets(buf, sizeof(buf), fp) && !strcmp(buf, rsa_signature)) {\r
256 memset(&key, 0, sizeof(key));\r
257 if (loadrsakey_main(fp, &key, TRUE, commentptr, NULL, &error)) {\r
258 *blob = rsa_public_blob(&key, bloblen);\r
259 freersakey(&key);\r
260 ret = 1;\r
261 }\r
262 fp = NULL; /* loadrsakey_main unconditionally closes fp */\r
263 } else {\r
264 error = "not an SSH-1 RSA file";\r
265 }\r
266 \r
267 end:\r
268 if (fp)\r
269 fclose(fp);\r
270 if ((ret != 1) && errorstr)\r
271 *errorstr = error;\r
272 return ret;\r
273 }\r
274 \r
275 /*\r
276 * Save an RSA key file. Return nonzero on success.\r
277 */\r
278 int saversakey(const Filename *filename, struct RSAKey *key, char *passphrase)\r
279 {\r
280 unsigned char buf[16384];\r
281 unsigned char keybuf[16];\r
282 struct MD5Context md5c;\r
283 unsigned char *p, *estart;\r
284 FILE *fp;\r
285 \r
286 /*\r
287 * Write the initial signature.\r
288 */\r
289 p = buf;\r
290 memcpy(p, rsa_signature, sizeof(rsa_signature));\r
291 p += sizeof(rsa_signature);\r
292 \r
293 /*\r
294 * One byte giving encryption type, and one reserved (zero)\r
295 * uint32.\r
296 */\r
297 *p++ = (passphrase ? SSH_CIPHER_3DES : 0);\r
298 PUT_32BIT(p, 0);\r
299 p += 4;\r
300 \r
301 /*\r
302 * An ordinary SSH-1 public key consists of: a uint32\r
303 * containing the bit count, then two bignums containing the\r
304 * modulus and exponent respectively.\r
305 */\r
306 PUT_32BIT(p, bignum_bitcount(key->modulus));\r
307 p += 4;\r
308 p += ssh1_write_bignum(p, key->modulus);\r
309 p += ssh1_write_bignum(p, key->exponent);\r
310 \r
311 /*\r
312 * A string containing the comment field.\r
313 */\r
314 if (key->comment) {\r
315 PUT_32BIT(p, strlen(key->comment));\r
316 p += 4;\r
317 memcpy(p, key->comment, strlen(key->comment));\r
318 p += strlen(key->comment);\r
319 } else {\r
320 PUT_32BIT(p, 0);\r
321 p += 4;\r
322 }\r
323 \r
324 /*\r
325 * The encrypted portion starts here.\r
326 */\r
327 estart = p;\r
328 \r
329 /*\r
330 * Two bytes, then the same two bytes repeated.\r
331 */\r
332 *p++ = random_byte();\r
333 *p++ = random_byte();\r
334 p[0] = p[-2];\r
335 p[1] = p[-1];\r
336 p += 2;\r
337 \r
338 /*\r
339 * Four more bignums: the decryption exponent, then iqmp, then\r
340 * q, then p.\r
341 */\r
342 p += ssh1_write_bignum(p, key->private_exponent);\r
343 p += ssh1_write_bignum(p, key->iqmp);\r
344 p += ssh1_write_bignum(p, key->q);\r
345 p += ssh1_write_bignum(p, key->p);\r
346 \r
347 /*\r
348 * Now write zeros until the encrypted portion is a multiple of\r
349 * 8 bytes.\r
350 */\r
351 while ((p - estart) % 8)\r
352 *p++ = '\0';\r
353 \r
354 /*\r
355 * Now encrypt the encrypted portion.\r
356 */\r
357 if (passphrase) {\r
358 MD5Init(&md5c);\r
359 MD5Update(&md5c, (unsigned char *)passphrase, strlen(passphrase));\r
360 MD5Final(keybuf, &md5c);\r
361 des3_encrypt_pubkey(keybuf, estart, p - estart);\r
362 smemclr(keybuf, sizeof(keybuf)); /* burn the evidence */\r
363 }\r
364 \r
365 /*\r
366 * Done. Write the result to the file.\r
367 */\r
368 fp = f_open(filename, "wb", TRUE);\r
369 if (fp) {\r
370 int ret = (fwrite(buf, 1, p - buf, fp) == (size_t) (p - buf));\r
371 if (fclose(fp))\r
372 ret = 0;\r
373 return ret;\r
374 } else\r
375 return 0;\r
376 }\r
377 \r
378 /* ----------------------------------------------------------------------\r
379 * SSH-2 private key load/store functions.\r
380 */\r
381 \r
382 /*\r
383 * PuTTY's own format for SSH-2 keys is as follows:\r
384 *\r
385 * The file is text. Lines are terminated by CRLF, although CR-only\r
386 * and LF-only are tolerated on input.\r
387 *\r
388 * The first line says "PuTTY-User-Key-File-2: " plus the name of the\r
389 * algorithm ("ssh-dss", "ssh-rsa" etc).\r
390 *\r
391 * The next line says "Encryption: " plus an encryption type.\r
392 * Currently the only supported encryption types are "aes256-cbc"\r
393 * and "none".\r
394 *\r
395 * The next line says "Comment: " plus the comment string.\r
396 *\r
397 * Next there is a line saying "Public-Lines: " plus a number N.\r
398 * The following N lines contain a base64 encoding of the public\r
399 * part of the key. This is encoded as the standard SSH-2 public key\r
400 * blob (with no initial length): so for RSA, for example, it will\r
401 * read\r
402 *\r
403 * string "ssh-rsa"\r
404 * mpint exponent\r
405 * mpint modulus\r
406 *\r
407 * Next, there is a line saying "Private-Lines: " plus a number N,\r
408 * and then N lines containing the (potentially encrypted) private\r
409 * part of the key. For the key type "ssh-rsa", this will be\r
410 * composed of\r
411 *\r
412 * mpint private_exponent\r
413 * mpint p (the larger of the two primes)\r
414 * mpint q (the smaller prime)\r
415 * mpint iqmp (the inverse of q modulo p)\r
416 * data padding (to reach a multiple of the cipher block size)\r
417 *\r
418 * And for "ssh-dss", it will be composed of\r
419 *\r
420 * mpint x (the private key parameter)\r
421 * [ string hash 20-byte hash of mpints p || q || g only in old format ]\r
422 * \r
423 * Finally, there is a line saying "Private-MAC: " plus a hex\r
424 * representation of a HMAC-SHA-1 of:\r
425 *\r
426 * string name of algorithm ("ssh-dss", "ssh-rsa")\r
427 * string encryption type\r
428 * string comment\r
429 * string public-blob\r
430 * string private-plaintext (the plaintext version of the\r
431 * private part, including the final\r
432 * padding)\r
433 * \r
434 * The key to the MAC is itself a SHA-1 hash of:\r
435 * \r
436 * data "putty-private-key-file-mac-key"\r
437 * data passphrase\r
438 *\r
439 * (An empty passphrase is used for unencrypted keys.)\r
440 *\r
441 * If the key is encrypted, the encryption key is derived from the\r
442 * passphrase by means of a succession of SHA-1 hashes. Each hash\r
443 * is the hash of:\r
444 *\r
445 * uint32 sequence-number\r
446 * data passphrase\r
447 *\r
448 * where the sequence-number increases from zero. As many of these\r
449 * hashes are used as necessary.\r
450 *\r
451 * For backwards compatibility with snapshots between 0.51 and\r
452 * 0.52, we also support the older key file format, which begins\r
453 * with "PuTTY-User-Key-File-1" (version number differs). In this\r
454 * format the Private-MAC: field only covers the private-plaintext\r
455 * field and nothing else (and without the 4-byte string length on\r
456 * the front too). Moreover, the Private-MAC: field can be replaced\r
457 * with a Private-Hash: field which is a plain SHA-1 hash instead of\r
458 * an HMAC (this was generated for unencrypted keys).\r
459 */\r
460 \r
461 static int read_header(FILE * fp, char *header)\r
462 {\r
463 int len = 39;\r
464 int c;\r
465 \r
466 while (1) {\r
467 c = fgetc(fp);\r
468 if (c == '\n' || c == '\r' || c == EOF)\r
469 return 0; /* failure */\r
470 if (c == ':') {\r
471 c = fgetc(fp);\r
472 if (c != ' ')\r
473 return 0;\r
474 *header = '\0';\r
475 return 1; /* success! */\r
476 }\r
477 if (len == 0)\r
478 return 0; /* failure */\r
479 *header++ = c;\r
480 len--;\r
481 }\r
482 return 0; /* failure */\r
483 }\r
484 \r
485 static char *read_body(FILE * fp)\r
486 {\r
487 char *text;\r
488 int len;\r
489 int size;\r
490 int c;\r
491 \r
492 size = 128;\r
493 text = snewn(size, char);\r
494 len = 0;\r
495 text[len] = '\0';\r
496 \r
497 while (1) {\r
498 c = fgetc(fp);\r
499 if (c == '\r' || c == '\n' || c == EOF) {\r
500 if (c != EOF) {\r
501 c = fgetc(fp);\r
502 if (c != '\r' && c != '\n')\r
503 ungetc(c, fp);\r
504 }\r
505 return text;\r
506 }\r
507 if (len + 1 >= size) {\r
508 size += 128;\r
509 text = sresize(text, size, char);\r
510 }\r
511 text[len++] = c;\r
512 text[len] = '\0';\r
513 }\r
514 }\r
515 \r
516 static unsigned char *read_blob(FILE * fp, int nlines, int *bloblen)\r
517 {\r
518 unsigned char *blob;\r
519 char *line;\r
520 int linelen, len;\r
521 int i, j, k;\r
522 \r
523 /* We expect at most 64 base64 characters, ie 48 real bytes, per line. */\r
524 blob = snewn(48 * nlines, unsigned char);\r
525 len = 0;\r
526 for (i = 0; i < nlines; i++) {\r
527 line = read_body(fp);\r
528 if (!line) {\r
529 sfree(blob);\r
530 return NULL;\r
531 }\r
532 linelen = strlen(line);\r
533 if (linelen % 4 != 0 || linelen > 64) {\r
534 sfree(blob);\r
535 sfree(line);\r
536 return NULL;\r
537 }\r
538 for (j = 0; j < linelen; j += 4) {\r
539 k = base64_decode_atom(line + j, blob + len);\r
540 if (!k) {\r
541 sfree(line);\r
542 sfree(blob);\r
543 return NULL;\r
544 }\r
545 len += k;\r
546 }\r
547 sfree(line);\r
548 }\r
549 *bloblen = len;\r
550 return blob;\r
551 }\r
552 \r
553 /*\r
554 * Magic error return value for when the passphrase is wrong.\r
555 */\r
556 struct ssh2_userkey ssh2_wrong_passphrase = {\r
557 NULL, NULL, NULL\r
558 };\r
559 \r
560 const struct ssh_signkey *find_pubkey_alg(const char *name)\r
561 {\r
562 if (!strcmp(name, "ssh-rsa"))\r
563 return &ssh_rsa;\r
564 else if (!strcmp(name, "ssh-dss"))\r
565 return &ssh_dss;\r
566 else\r
567 return NULL;\r
568 }\r
569 \r
570 struct ssh2_userkey *ssh2_load_userkey(const Filename *filename,\r
571 char *passphrase, const char **errorstr)\r
572 {\r
573 FILE *fp;\r
574 char header[40], *b, *encryption, *comment, *mac;\r
575 const struct ssh_signkey *alg;\r
576 struct ssh2_userkey *ret;\r
577 int cipher, cipherblk;\r
578 unsigned char *public_blob, *private_blob;\r
579 int public_blob_len, private_blob_len;\r
580 int i, is_mac, old_fmt;\r
581 int passlen = passphrase ? strlen(passphrase) : 0;\r
582 const char *error = NULL;\r
583 \r
584 ret = NULL; /* return NULL for most errors */\r
585 encryption = comment = mac = NULL;\r
586 public_blob = private_blob = NULL;\r
587 \r
588 fp = f_open(filename, "rb", FALSE);\r
589 if (!fp) {\r
590 error = "can't open file";\r
591 goto error;\r
592 }\r
593 \r
594 /* Read the first header line which contains the key type. */\r
595 if (!read_header(fp, header))\r
596 goto error;\r
597 if (0 == strcmp(header, "PuTTY-User-Key-File-2")) {\r
598 old_fmt = 0;\r
599 } else if (0 == strcmp(header, "PuTTY-User-Key-File-1")) {\r
600 /* this is an old key file; warn and then continue */\r
601 old_keyfile_warning();\r
602 old_fmt = 1;\r
603 } else if (0 == strncmp(header, "PuTTY-User-Key-File-", 20)) {\r
604 /* this is a key file FROM THE FUTURE; refuse it, but with a\r
605 * more specific error message than the generic one below */\r
606 error = "PuTTY key format too new";\r
607 goto error;\r
608 } else {\r
609 error = "not a PuTTY SSH-2 private key";\r
610 goto error;\r
611 }\r
612 error = "file format error";\r
613 if ((b = read_body(fp)) == NULL)\r
614 goto error;\r
615 /* Select key algorithm structure. */\r
616 alg = find_pubkey_alg(b);\r
617 if (!alg) {\r
618 sfree(b);\r
619 goto error;\r
620 }\r
621 sfree(b);\r
622 \r
623 /* Read the Encryption header line. */\r
624 if (!read_header(fp, header) || 0 != strcmp(header, "Encryption"))\r
625 goto error;\r
626 if ((encryption = read_body(fp)) == NULL)\r
627 goto error;\r
628 if (!strcmp(encryption, "aes256-cbc")) {\r
629 cipher = 1;\r
630 cipherblk = 16;\r
631 } else if (!strcmp(encryption, "none")) {\r
632 cipher = 0;\r
633 cipherblk = 1;\r
634 } else {\r
635 goto error;\r
636 }\r
637 \r
638 /* Read the Comment header line. */\r
639 if (!read_header(fp, header) || 0 != strcmp(header, "Comment"))\r
640 goto error;\r
641 if ((comment = read_body(fp)) == NULL)\r
642 goto error;\r
643 \r
644 /* Read the Public-Lines header line and the public blob. */\r
645 if (!read_header(fp, header) || 0 != strcmp(header, "Public-Lines"))\r
646 goto error;\r
647 if ((b = read_body(fp)) == NULL)\r
648 goto error;\r
649 i = atoi(b);\r
650 sfree(b);\r
651 if ((public_blob = read_blob(fp, i, &public_blob_len)) == NULL)\r
652 goto error;\r
653 \r
654 /* Read the Private-Lines header line and the Private blob. */\r
655 if (!read_header(fp, header) || 0 != strcmp(header, "Private-Lines"))\r
656 goto error;\r
657 if ((b = read_body(fp)) == NULL)\r
658 goto error;\r
659 i = atoi(b);\r
660 sfree(b);\r
661 if ((private_blob = read_blob(fp, i, &private_blob_len)) == NULL)\r
662 goto error;\r
663 \r
664 /* Read the Private-MAC or Private-Hash header line. */\r
665 if (!read_header(fp, header))\r
666 goto error;\r
667 if (0 == strcmp(header, "Private-MAC")) {\r
668 if ((mac = read_body(fp)) == NULL)\r
669 goto error;\r
670 is_mac = 1;\r
671 } else if (0 == strcmp(header, "Private-Hash") && old_fmt) {\r
672 if ((mac = read_body(fp)) == NULL)\r
673 goto error;\r
674 is_mac = 0;\r
675 } else\r
676 goto error;\r
677 \r
678 fclose(fp);\r
679 fp = NULL;\r
680 \r
681 /*\r
682 * Decrypt the private blob.\r
683 */\r
684 if (cipher) {\r
685 unsigned char key[40];\r
686 SHA_State s;\r
687 \r
688 if (!passphrase)\r
689 goto error;\r
690 if (private_blob_len % cipherblk)\r
691 goto error;\r
692 \r
693 SHA_Init(&s);\r
694 SHA_Bytes(&s, "\0\0\0\0", 4);\r
695 SHA_Bytes(&s, passphrase, passlen);\r
696 SHA_Final(&s, key + 0);\r
697 SHA_Init(&s);\r
698 SHA_Bytes(&s, "\0\0\0\1", 4);\r
699 SHA_Bytes(&s, passphrase, passlen);\r
700 SHA_Final(&s, key + 20);\r
701 aes256_decrypt_pubkey(key, private_blob, private_blob_len);\r
702 }\r
703 \r
704 /*\r
705 * Verify the MAC.\r
706 */\r
707 {\r
708 char realmac[41];\r
709 unsigned char binary[20];\r
710 unsigned char *macdata;\r
711 int maclen;\r
712 int free_macdata;\r
713 \r
714 if (old_fmt) {\r
715 /* MAC (or hash) only covers the private blob. */\r
716 macdata = private_blob;\r
717 maclen = private_blob_len;\r
718 free_macdata = 0;\r
719 } else {\r
720 unsigned char *p;\r
721 int namelen = strlen(alg->name);\r
722 int enclen = strlen(encryption);\r
723 int commlen = strlen(comment);\r
724 maclen = (4 + namelen +\r
725 4 + enclen +\r
726 4 + commlen +\r
727 4 + public_blob_len +\r
728 4 + private_blob_len);\r
729 macdata = snewn(maclen, unsigned char);\r
730 p = macdata;\r
731 #define DO_STR(s,len) PUT_32BIT(p,(len));memcpy(p+4,(s),(len));p+=4+(len)\r
732 DO_STR(alg->name, namelen);\r
733 DO_STR(encryption, enclen);\r
734 DO_STR(comment, commlen);\r
735 DO_STR(public_blob, public_blob_len);\r
736 DO_STR(private_blob, private_blob_len);\r
737 \r
738 free_macdata = 1;\r
739 }\r
740 \r
741 if (is_mac) {\r
742 SHA_State s;\r
743 unsigned char mackey[20];\r
744 char header[] = "putty-private-key-file-mac-key";\r
745 \r
746 SHA_Init(&s);\r
747 SHA_Bytes(&s, header, sizeof(header)-1);\r
748 if (cipher && passphrase)\r
749 SHA_Bytes(&s, passphrase, passlen);\r
750 SHA_Final(&s, mackey);\r
751 \r
752 hmac_sha1_simple(mackey, 20, macdata, maclen, binary);\r
753 \r
754 smemclr(mackey, sizeof(mackey));\r
755 smemclr(&s, sizeof(s));\r
756 } else {\r
757 SHA_Simple(macdata, maclen, binary);\r
758 }\r
759 \r
760 if (free_macdata) {\r
761 smemclr(macdata, maclen);\r
762 sfree(macdata);\r
763 }\r
764 \r
765 for (i = 0; i < 20; i++)\r
766 sprintf(realmac + 2 * i, "%02x", binary[i]);\r
767 \r
768 if (strcmp(mac, realmac)) {\r
769 /* An incorrect MAC is an unconditional Error if the key is\r
770 * unencrypted. Otherwise, it means Wrong Passphrase. */\r
771 if (cipher) {\r
772 error = "wrong passphrase";\r
773 ret = SSH2_WRONG_PASSPHRASE;\r
774 } else {\r
775 error = "MAC failed";\r
776 ret = NULL;\r
777 }\r
778 goto error;\r
779 }\r
780 }\r
781 sfree(mac);\r
782 mac = NULL;\r
783 \r
784 /*\r
785 * Create and return the key.\r
786 */\r
787 ret = snew(struct ssh2_userkey);\r
788 ret->alg = alg;\r
789 ret->comment = comment;\r
790 ret->data = alg->createkey(public_blob, public_blob_len,\r
791 private_blob, private_blob_len);\r
792 if (!ret->data) {\r
793 sfree(ret);\r
794 ret = NULL;\r
795 error = "createkey failed";\r
796 goto error;\r
797 }\r
798 sfree(public_blob);\r
799 smemclr(private_blob, private_blob_len);\r
800 sfree(private_blob);\r
801 sfree(encryption);\r
802 if (errorstr)\r
803 *errorstr = NULL;\r
804 return ret;\r
805 \r
806 /*\r
807 * Error processing.\r
808 */\r
809 error:\r
810 if (fp)\r
811 fclose(fp);\r
812 if (comment)\r
813 sfree(comment);\r
814 if (encryption)\r
815 sfree(encryption);\r
816 if (mac)\r
817 sfree(mac);\r
818 if (public_blob)\r
819 sfree(public_blob);\r
820 if (private_blob) {\r
821 smemclr(private_blob, private_blob_len);\r
822 sfree(private_blob);\r
823 }\r
824 if (errorstr)\r
825 *errorstr = error;\r
826 return ret;\r
827 }\r
828 \r
829 unsigned char *ssh2_userkey_loadpub(const Filename *filename, char **algorithm,\r
830 int *pub_blob_len, char **commentptr,\r
831 const char **errorstr)\r
832 {\r
833 FILE *fp;\r
834 char header[40], *b;\r
835 const struct ssh_signkey *alg;\r
836 unsigned char *public_blob;\r
837 int public_blob_len;\r
838 int i;\r
839 const char *error = NULL;\r
840 char *comment;\r
841 \r
842 public_blob = NULL;\r
843 \r
844 fp = f_open(filename, "rb", FALSE);\r
845 if (!fp) {\r
846 error = "can't open file";\r
847 goto error;\r
848 }\r
849 \r
850 /* Read the first header line which contains the key type. */\r
851 if (!read_header(fp, header)\r
852 || (0 != strcmp(header, "PuTTY-User-Key-File-2") &&\r
853 0 != strcmp(header, "PuTTY-User-Key-File-1"))) {\r
854 if (0 == strncmp(header, "PuTTY-User-Key-File-", 20))\r
855 error = "PuTTY key format too new";\r
856 else\r
857 error = "not a PuTTY SSH-2 private key";\r
858 goto error;\r
859 }\r
860 error = "file format error";\r
861 if ((b = read_body(fp)) == NULL)\r
862 goto error;\r
863 /* Select key algorithm structure. */\r
864 alg = find_pubkey_alg(b);\r
865 if (!alg) {\r
866 sfree(b);\r
867 goto error;\r
868 }\r
869 sfree(b);\r
870 \r
871 /* Read the Encryption header line. */\r
872 if (!read_header(fp, header) || 0 != strcmp(header, "Encryption"))\r
873 goto error;\r
874 if ((b = read_body(fp)) == NULL)\r
875 goto error;\r
876 sfree(b); /* we don't care */\r
877 \r
878 /* Read the Comment header line. */\r
879 if (!read_header(fp, header) || 0 != strcmp(header, "Comment"))\r
880 goto error;\r
881 if ((comment = read_body(fp)) == NULL)\r
882 goto error;\r
883 \r
884 if (commentptr)\r
885 *commentptr = comment;\r
886 else\r
887 sfree(comment);\r
888 \r
889 /* Read the Public-Lines header line and the public blob. */\r
890 if (!read_header(fp, header) || 0 != strcmp(header, "Public-Lines"))\r
891 goto error;\r
892 if ((b = read_body(fp)) == NULL)\r
893 goto error;\r
894 i = atoi(b);\r
895 sfree(b);\r
896 if ((public_blob = read_blob(fp, i, &public_blob_len)) == NULL)\r
897 goto error;\r
898 \r
899 fclose(fp);\r
900 if (pub_blob_len)\r
901 *pub_blob_len = public_blob_len;\r
902 if (algorithm)\r
903 *algorithm = alg->name;\r
904 return public_blob;\r
905 \r
906 /*\r
907 * Error processing.\r
908 */\r
909 error:\r
910 if (fp)\r
911 fclose(fp);\r
912 if (public_blob)\r
913 sfree(public_blob);\r
914 if (errorstr)\r
915 *errorstr = error;\r
916 return NULL;\r
917 }\r
918 \r
919 int ssh2_userkey_encrypted(const Filename *filename, char **commentptr)\r
920 {\r
921 FILE *fp;\r
922 char header[40], *b, *comment;\r
923 int ret;\r
924 \r
925 if (commentptr)\r
926 *commentptr = NULL;\r
927 \r
928 fp = f_open(filename, "rb", FALSE);\r
929 if (!fp)\r
930 return 0;\r
931 if (!read_header(fp, header)\r
932 || (0 != strcmp(header, "PuTTY-User-Key-File-2") &&\r
933 0 != strcmp(header, "PuTTY-User-Key-File-1"))) {\r
934 fclose(fp);\r
935 return 0;\r
936 }\r
937 if ((b = read_body(fp)) == NULL) {\r
938 fclose(fp);\r
939 return 0;\r
940 }\r
941 sfree(b); /* we don't care about key type here */\r
942 /* Read the Encryption header line. */\r
943 if (!read_header(fp, header) || 0 != strcmp(header, "Encryption")) {\r
944 fclose(fp);\r
945 return 0;\r
946 }\r
947 if ((b = read_body(fp)) == NULL) {\r
948 fclose(fp);\r
949 return 0;\r
950 }\r
951 \r
952 /* Read the Comment header line. */\r
953 if (!read_header(fp, header) || 0 != strcmp(header, "Comment")) {\r
954 fclose(fp);\r
955 sfree(b);\r
956 return 1;\r
957 }\r
958 if ((comment = read_body(fp)) == NULL) {\r
959 fclose(fp);\r
960 sfree(b);\r
961 return 1;\r
962 }\r
963 \r
964 if (commentptr)\r
965 *commentptr = comment;\r
966 else\r
967 sfree(comment);\r
968 \r
969 fclose(fp);\r
970 if (!strcmp(b, "aes256-cbc"))\r
971 ret = 1;\r
972 else\r
973 ret = 0;\r
974 sfree(b);\r
975 return ret;\r
976 }\r
977 \r
978 int base64_lines(int datalen)\r
979 {\r
980 /* When encoding, we use 64 chars/line, which equals 48 real chars. */\r
981 return (datalen + 47) / 48;\r
982 }\r
983 \r
984 void base64_encode(FILE * fp, unsigned char *data, int datalen, int cpl)\r
985 {\r
986 int linelen = 0;\r
987 char out[4];\r
988 int n, i;\r
989 \r
990 while (datalen > 0) {\r
991 n = (datalen < 3 ? datalen : 3);\r
992 base64_encode_atom(data, n, out);\r
993 data += n;\r
994 datalen -= n;\r
995 for (i = 0; i < 4; i++) {\r
996 if (linelen >= cpl) {\r
997 linelen = 0;\r
998 fputc('\n', fp);\r
999 }\r
1000 fputc(out[i], fp);\r
1001 linelen++;\r
1002 }\r
1003 }\r
1004 fputc('\n', fp);\r
1005 }\r
1006 \r
1007 int ssh2_save_userkey(const Filename *filename, struct ssh2_userkey *key,\r
1008 char *passphrase)\r
1009 {\r
1010 FILE *fp;\r
1011 unsigned char *pub_blob, *priv_blob, *priv_blob_encrypted;\r
1012 int pub_blob_len, priv_blob_len, priv_encrypted_len;\r
1013 int passlen;\r
1014 int cipherblk;\r
1015 int i;\r
1016 char *cipherstr;\r
1017 unsigned char priv_mac[20];\r
1018 \r
1019 /*\r
1020 * Fetch the key component blobs.\r
1021 */\r
1022 pub_blob = key->alg->public_blob(key->data, &pub_blob_len);\r
1023 priv_blob = key->alg->private_blob(key->data, &priv_blob_len);\r
1024 if (!pub_blob || !priv_blob) {\r
1025 sfree(pub_blob);\r
1026 sfree(priv_blob);\r
1027 return 0;\r
1028 }\r
1029 \r
1030 /*\r
1031 * Determine encryption details, and encrypt the private blob.\r
1032 */\r
1033 if (passphrase) {\r
1034 cipherstr = "aes256-cbc";\r
1035 cipherblk = 16;\r
1036 } else {\r
1037 cipherstr = "none";\r
1038 cipherblk = 1;\r
1039 }\r
1040 priv_encrypted_len = priv_blob_len + cipherblk - 1;\r
1041 priv_encrypted_len -= priv_encrypted_len % cipherblk;\r
1042 priv_blob_encrypted = snewn(priv_encrypted_len, unsigned char);\r
1043 memset(priv_blob_encrypted, 0, priv_encrypted_len);\r
1044 memcpy(priv_blob_encrypted, priv_blob, priv_blob_len);\r
1045 /* Create padding based on the SHA hash of the unpadded blob. This prevents\r
1046 * too easy a known-plaintext attack on the last block. */\r
1047 SHA_Simple(priv_blob, priv_blob_len, priv_mac);\r
1048 assert(priv_encrypted_len - priv_blob_len < 20);\r
1049 memcpy(priv_blob_encrypted + priv_blob_len, priv_mac,\r
1050 priv_encrypted_len - priv_blob_len);\r
1051 \r
1052 /* Now create the MAC. */\r
1053 {\r
1054 unsigned char *macdata;\r
1055 int maclen;\r
1056 unsigned char *p;\r
1057 int namelen = strlen(key->alg->name);\r
1058 int enclen = strlen(cipherstr);\r
1059 int commlen = strlen(key->comment);\r
1060 SHA_State s;\r
1061 unsigned char mackey[20];\r
1062 char header[] = "putty-private-key-file-mac-key";\r
1063 \r
1064 maclen = (4 + namelen +\r
1065 4 + enclen +\r
1066 4 + commlen +\r
1067 4 + pub_blob_len +\r
1068 4 + priv_encrypted_len);\r
1069 macdata = snewn(maclen, unsigned char);\r
1070 p = macdata;\r
1071 #define DO_STR(s,len) PUT_32BIT(p,(len));memcpy(p+4,(s),(len));p+=4+(len)\r
1072 DO_STR(key->alg->name, namelen);\r
1073 DO_STR(cipherstr, enclen);\r
1074 DO_STR(key->comment, commlen);\r
1075 DO_STR(pub_blob, pub_blob_len);\r
1076 DO_STR(priv_blob_encrypted, priv_encrypted_len);\r
1077 \r
1078 SHA_Init(&s);\r
1079 SHA_Bytes(&s, header, sizeof(header)-1);\r
1080 if (passphrase)\r
1081 SHA_Bytes(&s, passphrase, strlen(passphrase));\r
1082 SHA_Final(&s, mackey);\r
1083 hmac_sha1_simple(mackey, 20, macdata, maclen, priv_mac);\r
1084 smemclr(macdata, maclen);\r
1085 sfree(macdata);\r
1086 smemclr(mackey, sizeof(mackey));\r
1087 smemclr(&s, sizeof(s));\r
1088 }\r
1089 \r
1090 if (passphrase) {\r
1091 unsigned char key[40];\r
1092 SHA_State s;\r
1093 \r
1094 passlen = strlen(passphrase);\r
1095 \r
1096 SHA_Init(&s);\r
1097 SHA_Bytes(&s, "\0\0\0\0", 4);\r
1098 SHA_Bytes(&s, passphrase, passlen);\r
1099 SHA_Final(&s, key + 0);\r
1100 SHA_Init(&s);\r
1101 SHA_Bytes(&s, "\0\0\0\1", 4);\r
1102 SHA_Bytes(&s, passphrase, passlen);\r
1103 SHA_Final(&s, key + 20);\r
1104 aes256_encrypt_pubkey(key, priv_blob_encrypted,\r
1105 priv_encrypted_len);\r
1106 \r
1107 smemclr(key, sizeof(key));\r
1108 smemclr(&s, sizeof(s));\r
1109 }\r
1110 \r
1111 fp = f_open(filename, "w", TRUE);\r
1112 if (!fp) {\r
1113 sfree(pub_blob);\r
1114 smemclr(priv_blob, priv_blob_len);\r
1115 sfree(priv_blob);\r
1116 smemclr(priv_blob_encrypted, priv_blob_len);\r
1117 sfree(priv_blob_encrypted);\r
1118 return 0;\r
1119 }\r
1120 fprintf(fp, "PuTTY-User-Key-File-2: %s\n", key->alg->name);\r
1121 fprintf(fp, "Encryption: %s\n", cipherstr);\r
1122 fprintf(fp, "Comment: %s\n", key->comment);\r
1123 fprintf(fp, "Public-Lines: %d\n", base64_lines(pub_blob_len));\r
1124 base64_encode(fp, pub_blob, pub_blob_len, 64);\r
1125 fprintf(fp, "Private-Lines: %d\n", base64_lines(priv_encrypted_len));\r
1126 base64_encode(fp, priv_blob_encrypted, priv_encrypted_len, 64);\r
1127 fprintf(fp, "Private-MAC: ");\r
1128 for (i = 0; i < 20; i++)\r
1129 fprintf(fp, "%02x", priv_mac[i]);\r
1130 fprintf(fp, "\n");\r
1131 fclose(fp);\r
1132 \r
1133 sfree(pub_blob);\r
1134 smemclr(priv_blob, priv_blob_len);\r
1135 sfree(priv_blob);\r
1136 smemclr(priv_blob_encrypted, priv_blob_len);\r
1137 sfree(priv_blob_encrypted);\r
1138 return 1;\r
1139 }\r
1140 \r
1141 /* ----------------------------------------------------------------------\r
1142 * A function to determine the type of a private key file. Returns\r
1143 * 0 on failure, 1 or 2 on success.\r
1144 */\r
1145 int key_type(const Filename *filename)\r
1146 {\r
1147 FILE *fp;\r
1148 char buf[32];\r
1149 const char putty2_sig[] = "PuTTY-User-Key-File-";\r
1150 const char sshcom_sig[] = "---- BEGIN SSH2 ENCRYPTED PRIVAT";\r
1151 const char openssh_sig[] = "-----BEGIN ";\r
1152 int i;\r
1153 \r
1154 fp = f_open(filename, "r", FALSE);\r
1155 if (!fp)\r
1156 return SSH_KEYTYPE_UNOPENABLE;\r
1157 i = fread(buf, 1, sizeof(buf), fp);\r
1158 fclose(fp);\r
1159 if (i < 0)\r
1160 return SSH_KEYTYPE_UNOPENABLE;\r
1161 if (i < 32)\r
1162 return SSH_KEYTYPE_UNKNOWN;\r
1163 if (!memcmp(buf, rsa_signature, sizeof(rsa_signature)-1))\r
1164 return SSH_KEYTYPE_SSH1;\r
1165 if (!memcmp(buf, putty2_sig, sizeof(putty2_sig)-1))\r
1166 return SSH_KEYTYPE_SSH2;\r
1167 if (!memcmp(buf, openssh_sig, sizeof(openssh_sig)-1))\r
1168 return SSH_KEYTYPE_OPENSSH;\r
1169 if (!memcmp(buf, sshcom_sig, sizeof(sshcom_sig)-1))\r
1170 return SSH_KEYTYPE_SSHCOM;\r
1171 return SSH_KEYTYPE_UNKNOWN; /* unrecognised or EOF */\r
1172 }\r
1173 \r
1174 /*\r
1175 * Convert the type word to a string, for `wrong type' error\r
1176 * messages.\r
1177 */\r
1178 char *key_type_to_str(int type)\r
1179 {\r
1180 switch (type) {\r
1181 case SSH_KEYTYPE_UNOPENABLE: return "unable to open file"; break;\r
1182 case SSH_KEYTYPE_UNKNOWN: return "not a private key"; break;\r
1183 case SSH_KEYTYPE_SSH1: return "SSH-1 private key"; break;\r
1184 case SSH_KEYTYPE_SSH2: return "PuTTY SSH-2 private key"; break;\r
1185 case SSH_KEYTYPE_OPENSSH: return "OpenSSH SSH-2 private key"; break;\r
1186 case SSH_KEYTYPE_SSHCOM: return "ssh.com SSH-2 private key"; break;\r
1187 default: return "INTERNAL ERROR"; break;\r
1188 }\r
1189 }\r