| blob | f13e33bd8d62bb52dcf30b53ec919d8e59852344 |
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, 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 int base64_decode_atom(char *atom, unsigned char *out)\r
517 {\r
518 int vals[4];\r
519 int i, v, len;\r
520 unsigned word;\r
521 char c;\r
522 \r
523 for (i = 0; i < 4; i++) {\r
524 c = atom[i];\r
525 if (c >= 'A' && c <= 'Z')\r
526 v = c - 'A';\r
527 else if (c >= 'a' && c <= 'z')\r
528 v = c - 'a' + 26;\r
529 else if (c >= '0' && c <= '9')\r
530 v = c - '0' + 52;\r
531 else if (c == '+')\r
532 v = 62;\r
533 else if (c == '/')\r
534 v = 63;\r
535 else if (c == '=')\r
536 v = -1;\r
537 else\r
538 return 0; /* invalid atom */\r
539 vals[i] = v;\r
540 }\r
541 \r
542 if (vals[0] == -1 || vals[1] == -1)\r
543 return 0;\r
544 if (vals[2] == -1 && vals[3] != -1)\r
545 return 0;\r
546 \r
547 if (vals[3] != -1)\r
548 len = 3;\r
549 else if (vals[2] != -1)\r
550 len = 2;\r
551 else\r
552 len = 1;\r
553 \r
554 word = ((vals[0] << 18) |\r
555 (vals[1] << 12) | ((vals[2] & 0x3F) << 6) | (vals[3] & 0x3F));\r
556 out[0] = (word >> 16) & 0xFF;\r
557 if (len > 1)\r
558 out[1] = (word >> 8) & 0xFF;\r
559 if (len > 2)\r
560 out[2] = word & 0xFF;\r
561 return len;\r
562 }\r
563 \r
564 static unsigned char *read_blob(FILE * fp, int nlines, int *bloblen)\r
565 {\r
566 unsigned char *blob;\r
567 char *line;\r
568 int linelen, len;\r
569 int i, j, k;\r
570 \r
571 /* We expect at most 64 base64 characters, ie 48 real bytes, per line. */\r
572 blob = snewn(48 * nlines, unsigned char);\r
573 len = 0;\r
574 for (i = 0; i < nlines; i++) {\r
575 line = read_body(fp);\r
576 if (!line) {\r
577 sfree(blob);\r
578 return NULL;\r
579 }\r
580 linelen = strlen(line);\r
581 if (linelen % 4 != 0 || linelen > 64) {\r
582 sfree(blob);\r
583 sfree(line);\r
584 return NULL;\r
585 }\r
586 for (j = 0; j < linelen; j += 4) {\r
587 k = base64_decode_atom(line + j, blob + len);\r
588 if (!k) {\r
589 sfree(line);\r
590 sfree(blob);\r
591 return NULL;\r
592 }\r
593 len += k;\r
594 }\r
595 sfree(line);\r
596 }\r
597 *bloblen = len;\r
598 return blob;\r
599 }\r
600 \r
601 /*\r
602 * Magic error return value for when the passphrase is wrong.\r
603 */\r
604 struct ssh2_userkey ssh2_wrong_passphrase = {\r
605 NULL, NULL, NULL\r
606 };\r
607 \r
608 const struct ssh_signkey *find_pubkey_alg(const char *name)\r
609 {\r
610 if (!strcmp(name, "ssh-rsa"))\r
611 return &ssh_rsa;\r
612 else if (!strcmp(name, "ssh-dss"))\r
613 return &ssh_dss;\r
614 else\r
615 return NULL;\r
616 }\r
617 \r
618 struct ssh2_userkey *ssh2_load_userkey(const Filename *filename,\r
619 char *passphrase, const char **errorstr)\r
620 {\r
621 FILE *fp;\r
622 char header[40], *b, *encryption, *comment, *mac;\r
623 const struct ssh_signkey *alg;\r
624 struct ssh2_userkey *ret;\r
625 int cipher, cipherblk;\r
626 unsigned char *public_blob, *private_blob;\r
627 int public_blob_len, private_blob_len;\r
628 int i, is_mac, old_fmt;\r
629 int passlen = passphrase ? strlen(passphrase) : 0;\r
630 const char *error = NULL;\r
631 \r
632 ret = NULL; /* return NULL for most errors */\r
633 encryption = comment = mac = NULL;\r
634 public_blob = private_blob = NULL;\r
635 \r
636 fp = f_open(filename, "rb", FALSE);\r
637 if (!fp) {\r
638 error = "can't open file";\r
639 goto error;\r
640 }\r
641 \r
642 /* Read the first header line which contains the key type. */\r
643 if (!read_header(fp, header))\r
644 goto error;\r
645 if (0 == strcmp(header, "PuTTY-User-Key-File-2")) {\r
646 old_fmt = 0;\r
647 } else if (0 == strcmp(header, "PuTTY-User-Key-File-1")) {\r
648 /* this is an old key file; warn and then continue */\r
649 old_keyfile_warning();\r
650 old_fmt = 1;\r
651 } else if (0 == strncmp(header, "PuTTY-User-Key-File-", 20)) {\r
652 /* this is a key file FROM THE FUTURE; refuse it, but with a\r
653 * more specific error message than the generic one below */\r
654 error = "PuTTY key format too new";\r
655 goto error;\r
656 } else {\r
657 error = "not a PuTTY SSH-2 private key";\r
658 goto error;\r
659 }\r
660 error = "file format error";\r
661 if ((b = read_body(fp)) == NULL)\r
662 goto error;\r
663 /* Select key algorithm structure. */\r
664 alg = find_pubkey_alg(b);\r
665 if (!alg) {\r
666 sfree(b);\r
667 goto error;\r
668 }\r
669 sfree(b);\r
670 \r
671 /* Read the Encryption header line. */\r
672 if (!read_header(fp, header) || 0 != strcmp(header, "Encryption"))\r
673 goto error;\r
674 if ((encryption = read_body(fp)) == NULL)\r
675 goto error;\r
676 if (!strcmp(encryption, "aes256-cbc")) {\r
677 cipher = 1;\r
678 cipherblk = 16;\r
679 } else if (!strcmp(encryption, "none")) {\r
680 cipher = 0;\r
681 cipherblk = 1;\r
682 } else {\r
683 goto error;\r
684 }\r
685 \r
686 /* Read the Comment header line. */\r
687 if (!read_header(fp, header) || 0 != strcmp(header, "Comment"))\r
688 goto error;\r
689 if ((comment = read_body(fp)) == NULL)\r
690 goto error;\r
691 \r
692 /* Read the Public-Lines header line and the public blob. */\r
693 if (!read_header(fp, header) || 0 != strcmp(header, "Public-Lines"))\r
694 goto error;\r
695 if ((b = read_body(fp)) == NULL)\r
696 goto error;\r
697 i = atoi(b);\r
698 sfree(b);\r
699 if ((public_blob = read_blob(fp, i, &public_blob_len)) == NULL)\r
700 goto error;\r
701 \r
702 /* Read the Private-Lines header line and the Private blob. */\r
703 if (!read_header(fp, header) || 0 != strcmp(header, "Private-Lines"))\r
704 goto error;\r
705 if ((b = read_body(fp)) == NULL)\r
706 goto error;\r
707 i = atoi(b);\r
708 sfree(b);\r
709 if ((private_blob = read_blob(fp, i, &private_blob_len)) == NULL)\r
710 goto error;\r
711 \r
712 /* Read the Private-MAC or Private-Hash header line. */\r
713 if (!read_header(fp, header))\r
714 goto error;\r
715 if (0 == strcmp(header, "Private-MAC")) {\r
716 if ((mac = read_body(fp)) == NULL)\r
717 goto error;\r
718 is_mac = 1;\r
719 } else if (0 == strcmp(header, "Private-Hash") && old_fmt) {\r
720 if ((mac = read_body(fp)) == NULL)\r
721 goto error;\r
722 is_mac = 0;\r
723 } else\r
724 goto error;\r
725 \r
726 fclose(fp);\r
727 fp = NULL;\r
728 \r
729 /*\r
730 * Decrypt the private blob.\r
731 */\r
732 if (cipher) {\r
733 unsigned char key[40];\r
734 SHA_State s;\r
735 \r
736 if (!passphrase)\r
737 goto error;\r
738 if (private_blob_len % cipherblk)\r
739 goto error;\r
740 \r
741 SHA_Init(&s);\r
742 SHA_Bytes(&s, "\0\0\0\0", 4);\r
743 SHA_Bytes(&s, passphrase, passlen);\r
744 SHA_Final(&s, key + 0);\r
745 SHA_Init(&s);\r
746 SHA_Bytes(&s, "\0\0\0\1", 4);\r
747 SHA_Bytes(&s, passphrase, passlen);\r
748 SHA_Final(&s, key + 20);\r
749 aes256_decrypt_pubkey(key, private_blob, private_blob_len);\r
750 }\r
751 \r
752 /*\r
753 * Verify the MAC.\r
754 */\r
755 {\r
756 char realmac[41];\r
757 unsigned char binary[20];\r
758 unsigned char *macdata;\r
759 int maclen;\r
760 int free_macdata;\r
761 \r
762 if (old_fmt) {\r
763 /* MAC (or hash) only covers the private blob. */\r
764 macdata = private_blob;\r
765 maclen = private_blob_len;\r
766 free_macdata = 0;\r
767 } else {\r
768 unsigned char *p;\r
769 int namelen = strlen(alg->name);\r
770 int enclen = strlen(encryption);\r
771 int commlen = strlen(comment);\r
772 maclen = (4 + namelen +\r
773 4 + enclen +\r
774 4 + commlen +\r
775 4 + public_blob_len +\r
776 4 + private_blob_len);\r
777 macdata = snewn(maclen, unsigned char);\r
778 p = macdata;\r
779 #define DO_STR(s,len) PUT_32BIT(p,(len));memcpy(p+4,(s),(len));p+=4+(len)\r
780 DO_STR(alg->name, namelen);\r
781 DO_STR(encryption, enclen);\r
782 DO_STR(comment, commlen);\r
783 DO_STR(public_blob, public_blob_len);\r
784 DO_STR(private_blob, private_blob_len);\r
785 \r
786 free_macdata = 1;\r
787 }\r
788 \r
789 if (is_mac) {\r
790 SHA_State s;\r
791 unsigned char mackey[20];\r
792 char header[] = "putty-private-key-file-mac-key";\r
793 \r
794 SHA_Init(&s);\r
795 SHA_Bytes(&s, header, sizeof(header)-1);\r
796 if (cipher && passphrase)\r
797 SHA_Bytes(&s, passphrase, passlen);\r
798 SHA_Final(&s, mackey);\r
799 \r
800 hmac_sha1_simple(mackey, 20, macdata, maclen, binary);\r
801 \r
802 smemclr(mackey, sizeof(mackey));\r
803 smemclr(&s, sizeof(s));\r
804 } else {\r
805 SHA_Simple(macdata, maclen, binary);\r
806 }\r
807 \r
808 if (free_macdata) {\r
809 smemclr(macdata, maclen);\r
810 sfree(macdata);\r
811 }\r
812 \r
813 for (i = 0; i < 20; i++)\r
814 sprintf(realmac + 2 * i, "%02x", binary[i]);\r
815 \r
816 if (strcmp(mac, realmac)) {\r
817 /* An incorrect MAC is an unconditional Error if the key is\r
818 * unencrypted. Otherwise, it means Wrong Passphrase. */\r
819 if (cipher) {\r
820 error = "wrong passphrase";\r
821 ret = SSH2_WRONG_PASSPHRASE;\r
822 } else {\r
823 error = "MAC failed";\r
824 ret = NULL;\r
825 }\r
826 goto error;\r
827 }\r
828 }\r
829 sfree(mac);\r
830 \r
831 /*\r
832 * Create and return the key.\r
833 */\r
834 ret = snew(struct ssh2_userkey);\r
835 ret->alg = alg;\r
836 ret->comment = comment;\r
837 ret->data = alg->createkey(public_blob, public_blob_len,\r
838 private_blob, private_blob_len);\r
839 if (!ret->data) {\r
840 sfree(ret->comment);\r
841 sfree(ret);\r
842 ret = NULL;\r
843 error = "createkey failed";\r
844 goto error;\r
845 }\r
846 sfree(public_blob);\r
847 sfree(private_blob);\r
848 sfree(encryption);\r
849 if (errorstr)\r
850 *errorstr = NULL;\r
851 return ret;\r
852 \r
853 /*\r
854 * Error processing.\r
855 */\r
856 error:\r
857 if (fp)\r
858 fclose(fp);\r
859 if (comment)\r
860 sfree(comment);\r
861 if (encryption)\r
862 sfree(encryption);\r
863 if (mac)\r
864 sfree(mac);\r
865 if (public_blob)\r
866 sfree(public_blob);\r
867 if (private_blob)\r
868 sfree(private_blob);\r
869 if (errorstr)\r
870 *errorstr = error;\r
871 return ret;\r
872 }\r
873 \r
874 unsigned char *ssh2_userkey_loadpub(const Filename *filename, char **algorithm,\r
875 int *pub_blob_len, char **commentptr,\r
876 const char **errorstr)\r
877 {\r
878 FILE *fp;\r
879 char header[40], *b;\r
880 const struct ssh_signkey *alg;\r
881 unsigned char *public_blob;\r
882 int public_blob_len;\r
883 int i;\r
884 const char *error = NULL;\r
885 char *comment;\r
886 \r
887 public_blob = NULL;\r
888 \r
889 fp = f_open(filename, "rb", FALSE);\r
890 if (!fp) {\r
891 error = "can't open file";\r
892 goto error;\r
893 }\r
894 \r
895 /* Read the first header line which contains the key type. */\r
896 if (!read_header(fp, header)\r
897 || (0 != strcmp(header, "PuTTY-User-Key-File-2") &&\r
898 0 != strcmp(header, "PuTTY-User-Key-File-1"))) {\r
899 if (0 == strncmp(header, "PuTTY-User-Key-File-", 20))\r
900 error = "PuTTY key format too new";\r
901 else\r
902 error = "not a PuTTY SSH-2 private key";\r
903 goto error;\r
904 }\r
905 error = "file format error";\r
906 if ((b = read_body(fp)) == NULL)\r
907 goto error;\r
908 /* Select key algorithm structure. */\r
909 alg = find_pubkey_alg(b);\r
910 if (!alg) {\r
911 sfree(b);\r
912 goto error;\r
913 }\r
914 sfree(b);\r
915 \r
916 /* Read the Encryption header line. */\r
917 if (!read_header(fp, header) || 0 != strcmp(header, "Encryption"))\r
918 goto error;\r
919 if ((b = read_body(fp)) == NULL)\r
920 goto error;\r
921 sfree(b); /* we don't care */\r
922 \r
923 /* Read the Comment header line. */\r
924 if (!read_header(fp, header) || 0 != strcmp(header, "Comment"))\r
925 goto error;\r
926 if ((comment = read_body(fp)) == NULL)\r
927 goto error;\r
928 \r
929 if (commentptr)\r
930 *commentptr = comment;\r
931 else\r
932 sfree(comment);\r
933 \r
934 /* Read the Public-Lines header line and the public blob. */\r
935 if (!read_header(fp, header) || 0 != strcmp(header, "Public-Lines"))\r
936 goto error;\r
937 if ((b = read_body(fp)) == NULL)\r
938 goto error;\r
939 i = atoi(b);\r
940 sfree(b);\r
941 if ((public_blob = read_blob(fp, i, &public_blob_len)) == NULL)\r
942 goto error;\r
943 \r
944 fclose(fp);\r
945 if (pub_blob_len)\r
946 *pub_blob_len = public_blob_len;\r
947 if (algorithm)\r
948 *algorithm = alg->name;\r
949 return public_blob;\r
950 \r
951 /*\r
952 * Error processing.\r
953 */\r
954 error:\r
955 if (fp)\r
956 fclose(fp);\r
957 if (public_blob)\r
958 sfree(public_blob);\r
959 if (errorstr)\r
960 *errorstr = error;\r
961 return NULL;\r
962 }\r
963 \r
964 int ssh2_userkey_encrypted(const Filename *filename, char **commentptr)\r
965 {\r
966 FILE *fp;\r
967 char header[40], *b, *comment;\r
968 int ret;\r
969 \r
970 if (commentptr)\r
971 *commentptr = NULL;\r
972 \r
973 fp = f_open(filename, "rb", FALSE);\r
974 if (!fp)\r
975 return 0;\r
976 if (!read_header(fp, header)\r
977 || (0 != strcmp(header, "PuTTY-User-Key-File-2") &&\r
978 0 != strcmp(header, "PuTTY-User-Key-File-1"))) {\r
979 fclose(fp);\r
980 return 0;\r
981 }\r
982 if ((b = read_body(fp)) == NULL) {\r
983 fclose(fp);\r
984 return 0;\r
985 }\r
986 sfree(b); /* we don't care about key type here */\r
987 /* Read the Encryption header line. */\r
988 if (!read_header(fp, header) || 0 != strcmp(header, "Encryption")) {\r
989 fclose(fp);\r
990 return 0;\r
991 }\r
992 if ((b = read_body(fp)) == NULL) {\r
993 fclose(fp);\r
994 return 0;\r
995 }\r
996 \r
997 /* Read the Comment header line. */\r
998 if (!read_header(fp, header) || 0 != strcmp(header, "Comment")) {\r
999 fclose(fp);\r
1000 sfree(b);\r
1001 return 1;\r
1002 }\r
1003 if ((comment = read_body(fp)) == NULL) {\r
1004 fclose(fp);\r
1005 sfree(b);\r
1006 return 1;\r
1007 }\r
1008 \r
1009 if (commentptr)\r
1010 *commentptr = comment;\r
1011 else\r
1012 sfree(comment);\r
1013 \r
1014 fclose(fp);\r
1015 if (!strcmp(b, "aes256-cbc"))\r
1016 ret = 1;\r
1017 else\r
1018 ret = 0;\r
1019 sfree(b);\r
1020 return ret;\r
1021 }\r
1022 \r
1023 int base64_lines(int datalen)\r
1024 {\r
1025 /* When encoding, we use 64 chars/line, which equals 48 real chars. */\r
1026 return (datalen + 47) / 48;\r
1027 }\r
1028 \r
1029 void base64_encode(FILE * fp, unsigned char *data, int datalen, int cpl)\r
1030 {\r
1031 int linelen = 0;\r
1032 char out[4];\r
1033 int n, i;\r
1034 \r
1035 while (datalen > 0) {\r
1036 n = (datalen < 3 ? datalen : 3);\r
1037 base64_encode_atom(data, n, out);\r
1038 data += n;\r
1039 datalen -= n;\r
1040 for (i = 0; i < 4; i++) {\r
1041 if (linelen >= cpl) {\r
1042 linelen = 0;\r
1043 fputc('\n', fp);\r
1044 }\r
1045 fputc(out[i], fp);\r
1046 linelen++;\r
1047 }\r
1048 }\r
1049 fputc('\n', fp);\r
1050 }\r
1051 \r
1052 int ssh2_save_userkey(const Filename *filename, struct ssh2_userkey *key,\r
1053 char *passphrase)\r
1054 {\r
1055 FILE *fp;\r
1056 unsigned char *pub_blob, *priv_blob, *priv_blob_encrypted;\r
1057 int pub_blob_len, priv_blob_len, priv_encrypted_len;\r
1058 int passlen;\r
1059 int cipherblk;\r
1060 int i;\r
1061 char *cipherstr;\r
1062 unsigned char priv_mac[20];\r
1063 \r
1064 /*\r
1065 * Fetch the key component blobs.\r
1066 */\r
1067 pub_blob = key->alg->public_blob(key->data, &pub_blob_len);\r
1068 priv_blob = key->alg->private_blob(key->data, &priv_blob_len);\r
1069 if (!pub_blob || !priv_blob) {\r
1070 sfree(pub_blob);\r
1071 sfree(priv_blob);\r
1072 return 0;\r
1073 }\r
1074 \r
1075 /*\r
1076 * Determine encryption details, and encrypt the private blob.\r
1077 */\r
1078 if (passphrase) {\r
1079 cipherstr = "aes256-cbc";\r
1080 cipherblk = 16;\r
1081 } else {\r
1082 cipherstr = "none";\r
1083 cipherblk = 1;\r
1084 }\r
1085 priv_encrypted_len = priv_blob_len + cipherblk - 1;\r
1086 priv_encrypted_len -= priv_encrypted_len % cipherblk;\r
1087 priv_blob_encrypted = snewn(priv_encrypted_len, unsigned char);\r
1088 memset(priv_blob_encrypted, 0, priv_encrypted_len);\r
1089 memcpy(priv_blob_encrypted, priv_blob, priv_blob_len);\r
1090 /* Create padding based on the SHA hash of the unpadded blob. This prevents\r
1091 * too easy a known-plaintext attack on the last block. */\r
1092 SHA_Simple(priv_blob, priv_blob_len, priv_mac);\r
1093 assert(priv_encrypted_len - priv_blob_len < 20);\r
1094 memcpy(priv_blob_encrypted + priv_blob_len, priv_mac,\r
1095 priv_encrypted_len - priv_blob_len);\r
1096 \r
1097 /* Now create the MAC. */\r
1098 {\r
1099 unsigned char *macdata;\r
1100 int maclen;\r
1101 unsigned char *p;\r
1102 int namelen = strlen(key->alg->name);\r
1103 int enclen = strlen(cipherstr);\r
1104 int commlen = strlen(key->comment);\r
1105 SHA_State s;\r
1106 unsigned char mackey[20];\r
1107 char header[] = "putty-private-key-file-mac-key";\r
1108 \r
1109 maclen = (4 + namelen +\r
1110 4 + enclen +\r
1111 4 + commlen +\r
1112 4 + pub_blob_len +\r
1113 4 + priv_encrypted_len);\r
1114 macdata = snewn(maclen, unsigned char);\r
1115 p = macdata;\r
1116 #define DO_STR(s,len) PUT_32BIT(p,(len));memcpy(p+4,(s),(len));p+=4+(len)\r
1117 DO_STR(key->alg->name, namelen);\r
1118 DO_STR(cipherstr, enclen);\r
1119 DO_STR(key->comment, commlen);\r
1120 DO_STR(pub_blob, pub_blob_len);\r
1121 DO_STR(priv_blob_encrypted, priv_encrypted_len);\r
1122 \r
1123 SHA_Init(&s);\r
1124 SHA_Bytes(&s, header, sizeof(header)-1);\r
1125 if (passphrase)\r
1126 SHA_Bytes(&s, passphrase, strlen(passphrase));\r
1127 SHA_Final(&s, mackey);\r
1128 hmac_sha1_simple(mackey, 20, macdata, maclen, priv_mac);\r
1129 smemclr(macdata, maclen);\r
1130 sfree(macdata);\r
1131 smemclr(mackey, sizeof(mackey));\r
1132 smemclr(&s, sizeof(s));\r
1133 }\r
1134 \r
1135 if (passphrase) {\r
1136 unsigned char key[40];\r
1137 SHA_State s;\r
1138 \r
1139 passlen = strlen(passphrase);\r
1140 \r
1141 SHA_Init(&s);\r
1142 SHA_Bytes(&s, "\0\0\0\0", 4);\r
1143 SHA_Bytes(&s, passphrase, passlen);\r
1144 SHA_Final(&s, key + 0);\r
1145 SHA_Init(&s);\r
1146 SHA_Bytes(&s, "\0\0\0\1", 4);\r
1147 SHA_Bytes(&s, passphrase, passlen);\r
1148 SHA_Final(&s, key + 20);\r
1149 aes256_encrypt_pubkey(key, priv_blob_encrypted,\r
1150 priv_encrypted_len);\r
1151 \r
1152 smemclr(key, sizeof(key));\r
1153 smemclr(&s, sizeof(s));\r
1154 }\r
1155 \r
1156 fp = f_open(filename, "w", TRUE);\r
1157 if (!fp)\r
1158 return 0;\r
1159 fprintf(fp, "PuTTY-User-Key-File-2: %s\n", key->alg->name);\r
1160 fprintf(fp, "Encryption: %s\n", cipherstr);\r
1161 fprintf(fp, "Comment: %s\n", key->comment);\r
1162 fprintf(fp, "Public-Lines: %d\n", base64_lines(pub_blob_len));\r
1163 base64_encode(fp, pub_blob, pub_blob_len, 64);\r
1164 fprintf(fp, "Private-Lines: %d\n", base64_lines(priv_encrypted_len));\r
1165 base64_encode(fp, priv_blob_encrypted, priv_encrypted_len, 64);\r
1166 fprintf(fp, "Private-MAC: ");\r
1167 for (i = 0; i < 20; i++)\r
1168 fprintf(fp, "%02x", priv_mac[i]);\r
1169 fprintf(fp, "\n");\r
1170 fclose(fp);\r
1171 \r
1172 sfree(pub_blob);\r
1173 smemclr(priv_blob, priv_blob_len);\r
1174 sfree(priv_blob);\r
1175 sfree(priv_blob_encrypted);\r
1176 return 1;\r
1177 }\r
1178 \r
1179 /* ----------------------------------------------------------------------\r
1180 * A function to determine the type of a private key file. Returns\r
1181 * 0 on failure, 1 or 2 on success.\r
1182 */\r
1183 int key_type(const Filename *filename)\r
1184 {\r
1185 FILE *fp;\r
1186 char buf[32];\r
1187 const char putty2_sig[] = "PuTTY-User-Key-File-";\r
1188 const char sshcom_sig[] = "---- BEGIN SSH2 ENCRYPTED PRIVAT";\r
1189 const char openssh_sig[] = "-----BEGIN ";\r
1190 int i;\r
1191 \r
1192 fp = f_open(filename, "r", FALSE);\r
1193 if (!fp)\r
1194 return SSH_KEYTYPE_UNOPENABLE;\r
1195 i = fread(buf, 1, sizeof(buf), fp);\r
1196 fclose(fp);\r
1197 if (i < 0)\r
1198 return SSH_KEYTYPE_UNOPENABLE;\r
1199 if (i < 32)\r
1200 return SSH_KEYTYPE_UNKNOWN;\r
1201 if (!memcmp(buf, rsa_signature, sizeof(rsa_signature)-1))\r
1202 return SSH_KEYTYPE_SSH1;\r
1203 if (!memcmp(buf, putty2_sig, sizeof(putty2_sig)-1))\r
1204 return SSH_KEYTYPE_SSH2;\r
1205 if (!memcmp(buf, openssh_sig, sizeof(openssh_sig)-1))\r
1206 return SSH_KEYTYPE_OPENSSH;\r
1207 if (!memcmp(buf, sshcom_sig, sizeof(sshcom_sig)-1))\r
1208 return SSH_KEYTYPE_SSHCOM;\r
1209 return SSH_KEYTYPE_UNKNOWN; /* unrecognised or EOF */\r
1210 }\r
1211 \r
1212 /*\r
1213 * Convert the type word to a string, for `wrong type' error\r
1214 * messages.\r
1215 */\r
1216 char *key_type_to_str(int type)\r
1217 {\r
1218 switch (type) {\r
1219 case SSH_KEYTYPE_UNOPENABLE: return "unable to open file"; break;\r
1220 case SSH_KEYTYPE_UNKNOWN: return "not a private key"; break;\r
1221 case SSH_KEYTYPE_SSH1: return "SSH-1 private key"; break;\r
1222 case SSH_KEYTYPE_SSH2: return "PuTTY SSH-2 private key"; break;\r
1223 case SSH_KEYTYPE_OPENSSH: return "OpenSSH SSH-2 private key"; break;\r
1224 case SSH_KEYTYPE_SSHCOM: return "ssh.com SSH-2 private key"; break;\r
1225 default: return "INTERNAL ERROR"; break;\r
1226 }\r
1227 }\r