| blob | ee6166bd0daacb25c570b4c64eaef409d38a1ac4 |
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 i += makekey(buf + i, len, key, NULL, 1);\r
71 if (i < 0)\r
72 goto end; /* overran */\r
73 \r
74 /* Next, the comment field. */\r
75 j = GET_32BIT(buf + i);\r
76 i += 4;\r
77 if (len - i < j)\r
78 goto end;\r
79 comment = snewn(j + 1, char);\r
80 if (comment) {\r
81 memcpy(comment, buf + i, j);\r
82 comment[j] = '\0';\r
83 }\r
84 i += j;\r
85 if (commentptr)\r
86 *commentptr = dupstr(comment);\r
87 if (key)\r
88 key->comment = comment;\r
89 else\r
90 sfree(comment);\r
91 \r
92 if (pub_only) {\r
93 ret = 1;\r
94 goto end;\r
95 }\r
96 \r
97 if (!key) {\r
98 ret = ciphertype != 0;\r
99 *error = NULL;\r
100 goto end;\r
101 }\r
102 \r
103 /*\r
104 * Decrypt remainder of buffer.\r
105 */\r
106 if (ciphertype) {\r
107 MD5Init(&md5c);\r
108 MD5Update(&md5c, (unsigned char *)passphrase, strlen(passphrase));\r
109 MD5Final(keybuf, &md5c);\r
110 des3_decrypt_pubkey(keybuf, buf + i, (len - i + 7) & ~7);\r
111 memset(keybuf, 0, sizeof(keybuf)); /* burn the evidence */\r
112 }\r
113 \r
114 /*\r
115 * We are now in the secret part of the key. The first four\r
116 * bytes should be of the form a, b, a, b.\r
117 */\r
118 if (len - i < 4)\r
119 goto end;\r
120 if (buf[i] != buf[i + 2] || buf[i + 1] != buf[i + 3]) {\r
121 *error = "wrong passphrase";\r
122 ret = -1;\r
123 goto end;\r
124 }\r
125 i += 4;\r
126 \r
127 /*\r
128 * After that, we have one further bignum which is our\r
129 * decryption exponent, and then the three auxiliary values\r
130 * (iqmp, q, p).\r
131 */\r
132 j = makeprivate(buf + i, len - i, key);\r
133 if (j < 0) goto end;\r
134 i += j;\r
135 j = ssh1_read_bignum(buf + i, len - i, &key->iqmp);\r
136 if (j < 0) goto end;\r
137 i += j;\r
138 j = ssh1_read_bignum(buf + i, len - i, &key->q);\r
139 if (j < 0) goto end;\r
140 i += j;\r
141 j = ssh1_read_bignum(buf + i, len - i, &key->p);\r
142 if (j < 0) goto end;\r
143 i += j;\r
144 \r
145 if (!rsa_verify(key)) {\r
146 *error = "rsa_verify failed";\r
147 freersakey(key);\r
148 ret = 0;\r
149 } else\r
150 ret = 1;\r
151 \r
152 end:\r
153 memset(buf, 0, sizeof(buf)); /* burn the evidence */\r
154 return ret;\r
155 }\r
156 \r
157 int loadrsakey(const Filename *filename, struct RSAKey *key, char *passphrase,\r
158 const char **errorstr)\r
159 {\r
160 FILE *fp;\r
161 char buf[64];\r
162 int ret = 0;\r
163 const char *error = NULL;\r
164 \r
165 fp = f_open(*filename, "rb", FALSE);\r
166 if (!fp) {\r
167 error = "can't open file";\r
168 goto end;\r
169 }\r
170 \r
171 /*\r
172 * Read the first line of the file and see if it's a v1 private\r
173 * key file.\r
174 */\r
175 if (fgets(buf, sizeof(buf), fp) && !strcmp(buf, rsa_signature)) {\r
176 /*\r
177 * This routine will take care of calling fclose() for us.\r
178 */\r
179 ret = loadrsakey_main(fp, key, FALSE, NULL, passphrase, &error);\r
180 fp = NULL;\r
181 goto end;\r
182 }\r
183 \r
184 /*\r
185 * Otherwise, we have nothing. Return empty-handed.\r
186 */\r
187 error = "not an SSH-1 RSA file";\r
188 \r
189 end:\r
190 if (fp)\r
191 fclose(fp);\r
192 if ((ret != 1) && errorstr)\r
193 *errorstr = error;\r
194 return ret;\r
195 }\r
196 \r
197 /*\r
198 * See whether an RSA key is encrypted. Return its comment field as\r
199 * well.\r
200 */\r
201 int rsakey_encrypted(const Filename *filename, char **comment)\r
202 {\r
203 FILE *fp;\r
204 char buf[64];\r
205 \r
206 fp = f_open(*filename, "rb", FALSE);\r
207 if (!fp)\r
208 return 0; /* doesn't even exist */\r
209 \r
210 /*\r
211 * Read the first line of the file and see if it's a v1 private\r
212 * key file.\r
213 */\r
214 if (fgets(buf, sizeof(buf), fp) && !strcmp(buf, rsa_signature)) {\r
215 const char *dummy;\r
216 /*\r
217 * This routine will take care of calling fclose() for us.\r
218 */\r
219 return loadrsakey_main(fp, NULL, FALSE, comment, NULL, &dummy);\r
220 }\r
221 fclose(fp);\r
222 return 0; /* wasn't the right kind of file */\r
223 }\r
224 \r
225 /*\r
226 * Return a malloc'ed chunk of memory containing the public blob of\r
227 * an RSA key, as given in the agent protocol (modulus bits,\r
228 * exponent, modulus).\r
229 */\r
230 int rsakey_pubblob(const Filename *filename, void **blob, int *bloblen,\r
231 char **commentptr, const char **errorstr)\r
232 {\r
233 FILE *fp;\r
234 char buf[64];\r
235 struct RSAKey key;\r
236 int ret;\r
237 const char *error = NULL;\r
238 \r
239 /* Default return if we fail. */\r
240 *blob = NULL;\r
241 *bloblen = 0;\r
242 ret = 0;\r
243 \r
244 fp = f_open(*filename, "rb", FALSE);\r
245 if (!fp) {\r
246 error = "can't open file";\r
247 goto end;\r
248 }\r
249 \r
250 /*\r
251 * Read the first line of the file and see if it's a v1 private\r
252 * key file.\r
253 */\r
254 if (fgets(buf, sizeof(buf), fp) && !strcmp(buf, rsa_signature)) {\r
255 memset(&key, 0, sizeof(key));\r
256 if (loadrsakey_main(fp, &key, TRUE, commentptr, NULL, &error)) {\r
257 *blob = rsa_public_blob(&key, bloblen);\r
258 freersakey(&key);\r
259 ret = 1;\r
260 fp = NULL;\r
261 }\r
262 } else {\r
263 error = "not an SSH-1 RSA file";\r
264 }\r
265 \r
266 end:\r
267 if (fp)\r
268 fclose(fp);\r
269 if ((ret != 1) && errorstr)\r
270 *errorstr = error;\r
271 return ret;\r
272 }\r
273 \r
274 /*\r
275 * Save an RSA key file. Return nonzero on success.\r
276 */\r
277 int saversakey(const Filename *filename, struct RSAKey *key, char *passphrase)\r
278 {\r
279 unsigned char buf[16384];\r
280 unsigned char keybuf[16];\r
281 struct MD5Context md5c;\r
282 unsigned char *p, *estart;\r
283 FILE *fp;\r
284 \r
285 /*\r
286 * Write the initial signature.\r
287 */\r
288 p = buf;\r
289 memcpy(p, rsa_signature, sizeof(rsa_signature));\r
290 p += sizeof(rsa_signature);\r
291 \r
292 /*\r
293 * One byte giving encryption type, and one reserved (zero)\r
294 * uint32.\r
295 */\r
296 *p++ = (passphrase ? SSH_CIPHER_3DES : 0);\r
297 PUT_32BIT(p, 0);\r
298 p += 4;\r
299 \r
300 /*\r
301 * An ordinary SSH-1 public key consists of: a uint32\r
302 * containing the bit count, then two bignums containing the\r
303 * modulus and exponent respectively.\r
304 */\r
305 PUT_32BIT(p, bignum_bitcount(key->modulus));\r
306 p += 4;\r
307 p += ssh1_write_bignum(p, key->modulus);\r
308 p += ssh1_write_bignum(p, key->exponent);\r
309 \r
310 /*\r
311 * A string containing the comment field.\r
312 */\r
313 if (key->comment) {\r
314 PUT_32BIT(p, strlen(key->comment));\r
315 p += 4;\r
316 memcpy(p, key->comment, strlen(key->comment));\r
317 p += strlen(key->comment);\r
318 } else {\r
319 PUT_32BIT(p, 0);\r
320 p += 4;\r
321 }\r
322 \r
323 /*\r
324 * The encrypted portion starts here.\r
325 */\r
326 estart = p;\r
327 \r
328 /*\r
329 * Two bytes, then the same two bytes repeated.\r
330 */\r
331 *p++ = random_byte();\r
332 *p++ = random_byte();\r
333 p[0] = p[-2];\r
334 p[1] = p[-1];\r
335 p += 2;\r
336 \r
337 /*\r
338 * Four more bignums: the decryption exponent, then iqmp, then\r
339 * q, then p.\r
340 */\r
341 p += ssh1_write_bignum(p, key->private_exponent);\r
342 p += ssh1_write_bignum(p, key->iqmp);\r
343 p += ssh1_write_bignum(p, key->q);\r
344 p += ssh1_write_bignum(p, key->p);\r
345 \r
346 /*\r
347 * Now write zeros until the encrypted portion is a multiple of\r
348 * 8 bytes.\r
349 */\r
350 while ((p - estart) % 8)\r
351 *p++ = '\0';\r
352 \r
353 /*\r
354 * Now encrypt the encrypted portion.\r
355 */\r
356 if (passphrase) {\r
357 MD5Init(&md5c);\r
358 MD5Update(&md5c, (unsigned char *)passphrase, strlen(passphrase));\r
359 MD5Final(keybuf, &md5c);\r
360 des3_encrypt_pubkey(keybuf, estart, p - estart);\r
361 memset(keybuf, 0, sizeof(keybuf)); /* burn the evidence */\r
362 }\r
363 \r
364 /*\r
365 * Done. Write the result to the file.\r
366 */\r
367 fp = f_open(*filename, "wb", TRUE);\r
368 if (fp) {\r
369 int ret = (fwrite(buf, 1, p - buf, fp) == (size_t) (p - buf));\r
370 if (fclose(fp))\r
371 ret = 0;\r
372 return ret;\r
373 } else\r
374 return 0;\r
375 }\r
376 \r
377 /* ----------------------------------------------------------------------\r
378 * SSH-2 private key load/store functions.\r
379 */\r
380 \r
381 /*\r
382 * PuTTY's own format for SSH-2 keys is as follows:\r
383 *\r
384 * The file is text. Lines are terminated by CRLF, although CR-only\r
385 * and LF-only are tolerated on input.\r
386 *\r
387 * The first line says "PuTTY-User-Key-File-2: " plus the name of the\r
388 * algorithm ("ssh-dss", "ssh-rsa" etc).\r
389 *\r
390 * The next line says "Encryption: " plus an encryption type.\r
391 * Currently the only supported encryption types are "aes256-cbc"\r
392 * and "none".\r
393 *\r
394 * The next line says "Comment: " plus the comment string.\r
395 *\r
396 * Next there is a line saying "Public-Lines: " plus a number N.\r
397 * The following N lines contain a base64 encoding of the public\r
398 * part of the key. This is encoded as the standard SSH-2 public key\r
399 * blob (with no initial length): so for RSA, for example, it will\r
400 * read\r
401 *\r
402 * string "ssh-rsa"\r
403 * mpint exponent\r
404 * mpint modulus\r
405 *\r
406 * Next, there is a line saying "Private-Lines: " plus a number N,\r
407 * and then N lines containing the (potentially encrypted) private\r
408 * part of the key. For the key type "ssh-rsa", this will be\r
409 * composed of\r
410 *\r
411 * mpint private_exponent\r
412 * mpint p (the larger of the two primes)\r
413 * mpint q (the smaller prime)\r
414 * mpint iqmp (the inverse of q modulo p)\r
415 * data padding (to reach a multiple of the cipher block size)\r
416 *\r
417 * And for "ssh-dss", it will be composed of\r
418 *\r
419 * mpint x (the private key parameter)\r
420 * [ string hash 20-byte hash of mpints p || q || g only in old format ]\r
421 * \r
422 * Finally, there is a line saying "Private-MAC: " plus a hex\r
423 * representation of a HMAC-SHA-1 of:\r
424 *\r
425 * string name of algorithm ("ssh-dss", "ssh-rsa")\r
426 * string encryption type\r
427 * string comment\r
428 * string public-blob\r
429 * string private-plaintext (the plaintext version of the\r
430 * private part, including the final\r
431 * padding)\r
432 * \r
433 * The key to the MAC is itself a SHA-1 hash of:\r
434 * \r
435 * data "putty-private-key-file-mac-key"\r
436 * data passphrase\r
437 *\r
438 * (An empty passphrase is used for unencrypted keys.)\r
439 *\r
440 * If the key is encrypted, the encryption key is derived from the\r
441 * passphrase by means of a succession of SHA-1 hashes. Each hash\r
442 * is the hash of:\r
443 *\r
444 * uint32 sequence-number\r
445 * data passphrase\r
446 *\r
447 * where the sequence-number increases from zero. As many of these\r
448 * hashes are used as necessary.\r
449 *\r
450 * For backwards compatibility with snapshots between 0.51 and\r
451 * 0.52, we also support the older key file format, which begins\r
452 * with "PuTTY-User-Key-File-1" (version number differs). In this\r
453 * format the Private-MAC: field only covers the private-plaintext\r
454 * field and nothing else (and without the 4-byte string length on\r
455 * the front too). Moreover, the Private-MAC: field can be replaced\r
456 * with a Private-Hash: field which is a plain SHA-1 hash instead of\r
457 * an HMAC (this was generated for unencrypted keys).\r
458 */\r
459 \r
460 static int read_header(FILE * fp, char *header)\r
461 {\r
462 int len = 39;\r
463 int c;\r
464 \r
465 while (len > 0) {\r
466 c = fgetc(fp);\r
467 if (c == '\n' || c == '\r' || c == EOF)\r
468 return 0; /* failure */\r
469 if (c == ':') {\r
470 c = fgetc(fp);\r
471 if (c != ' ')\r
472 return 0;\r
473 *header = '\0';\r
474 return 1; /* success! */\r
475 }\r
476 if (len == 0)\r
477 return 0; /* failure */\r
478 *header++ = c;\r
479 len--;\r
480 }\r
481 return 0; /* failure */\r
482 }\r
483 \r
484 static char *read_body(FILE * fp)\r
485 {\r
486 char *text;\r
487 int len;\r
488 int size;\r
489 int c;\r
490 \r
491 size = 128;\r
492 text = snewn(size, char);\r
493 len = 0;\r
494 text[len] = '\0';\r
495 \r
496 while (1) {\r
497 c = fgetc(fp);\r
498 if (c == '\r' || c == '\n') {\r
499 c = fgetc(fp);\r
500 if (c != '\r' && c != '\n' && c != EOF)\r
501 ungetc(c, fp);\r
502 return text;\r
503 }\r
504 if (c == EOF) {\r
505 sfree(text);\r
506 return NULL;\r
507 }\r
508 if (len + 1 >= size) {\r
509 size += 128;\r
510 text = sresize(text, size, char);\r
511 }\r
512 text[len++] = c;\r
513 text[len] = '\0';\r
514 }\r
515 }\r
516 \r
517 int base64_decode_atom(char *atom, unsigned char *out)\r
518 {\r
519 int vals[4];\r
520 int i, v, len;\r
521 unsigned word;\r
522 char c;\r
523 \r
524 for (i = 0; i < 4; i++) {\r
525 c = atom[i];\r
526 if (c >= 'A' && c <= 'Z')\r
527 v = c - 'A';\r
528 else if (c >= 'a' && c <= 'z')\r
529 v = c - 'a' + 26;\r
530 else if (c >= '0' && c <= '9')\r
531 v = c - '0' + 52;\r
532 else if (c == '+')\r
533 v = 62;\r
534 else if (c == '/')\r
535 v = 63;\r
536 else if (c == '=')\r
537 v = -1;\r
538 else\r
539 return 0; /* invalid atom */\r
540 vals[i] = v;\r
541 }\r
542 \r
543 if (vals[0] == -1 || vals[1] == -1)\r
544 return 0;\r
545 if (vals[2] == -1 && vals[3] != -1)\r
546 return 0;\r
547 \r
548 if (vals[3] != -1)\r
549 len = 3;\r
550 else if (vals[2] != -1)\r
551 len = 2;\r
552 else\r
553 len = 1;\r
554 \r
555 word = ((vals[0] << 18) |\r
556 (vals[1] << 12) | ((vals[2] & 0x3F) << 6) | (vals[3] & 0x3F));\r
557 out[0] = (word >> 16) & 0xFF;\r
558 if (len > 1)\r
559 out[1] = (word >> 8) & 0xFF;\r
560 if (len > 2)\r
561 out[2] = word & 0xFF;\r
562 return len;\r
563 }\r
564 \r
565 static unsigned char *read_blob(FILE * fp, int nlines, int *bloblen)\r
566 {\r
567 unsigned char *blob;\r
568 char *line;\r
569 int linelen, len;\r
570 int i, j, k;\r
571 \r
572 /* We expect at most 64 base64 characters, ie 48 real bytes, per line. */\r
573 blob = snewn(48 * nlines, unsigned char);\r
574 len = 0;\r
575 for (i = 0; i < nlines; i++) {\r
576 line = read_body(fp);\r
577 if (!line) {\r
578 sfree(blob);\r
579 return NULL;\r
580 }\r
581 linelen = strlen(line);\r
582 if (linelen % 4 != 0 || linelen > 64) {\r
583 sfree(blob);\r
584 sfree(line);\r
585 return NULL;\r
586 }\r
587 for (j = 0; j < linelen; j += 4) {\r
588 k = base64_decode_atom(line + j, blob + len);\r
589 if (!k) {\r
590 sfree(line);\r
591 sfree(blob);\r
592 return NULL;\r
593 }\r
594 len += k;\r
595 }\r
596 sfree(line);\r
597 }\r
598 *bloblen = len;\r
599 return blob;\r
600 }\r
601 \r
602 /*\r
603 * Magic error return value for when the passphrase is wrong.\r
604 */\r
605 struct ssh2_userkey ssh2_wrong_passphrase = {\r
606 NULL, NULL, NULL\r
607 };\r
608 \r
609 const struct ssh_signkey *find_pubkey_alg(const char *name)\r
610 {\r
611 if (!strcmp(name, "ssh-rsa"))\r
612 return &ssh_rsa;\r
613 else if (!strcmp(name, "ssh-dss"))\r
614 return &ssh_dss;\r
615 else\r
616 return NULL;\r
617 }\r
618 \r
619 struct ssh2_userkey *ssh2_load_userkey(const Filename *filename,\r
620 char *passphrase, const char **errorstr)\r
621 {\r
622 FILE *fp;\r
623 char header[40], *b, *encryption, *comment, *mac;\r
624 const struct ssh_signkey *alg;\r
625 struct ssh2_userkey *ret;\r
626 int cipher, cipherblk;\r
627 unsigned char *public_blob, *private_blob;\r
628 int public_blob_len, private_blob_len;\r
629 int i, is_mac, old_fmt;\r
630 int passlen = passphrase ? strlen(passphrase) : 0;\r
631 const char *error = NULL;\r
632 \r
633 ret = NULL; /* return NULL for most errors */\r
634 encryption = comment = mac = NULL;\r
635 public_blob = private_blob = NULL;\r
636 \r
637 fp = f_open(*filename, "rb", FALSE);\r
638 if (!fp) {\r
639 error = "can't open file";\r
640 goto error;\r
641 }\r
642 \r
643 /* Read the first header line which contains the key type. */\r
644 if (!read_header(fp, header))\r
645 goto error;\r
646 if (0 == strcmp(header, "PuTTY-User-Key-File-2")) {\r
647 old_fmt = 0;\r
648 } else if (0 == strcmp(header, "PuTTY-User-Key-File-1")) {\r
649 /* this is an old key file; warn and then continue */\r
650 old_keyfile_warning();\r
651 old_fmt = 1;\r
652 } else {\r
653 error = "not a PuTTY SSH-2 private key";\r
654 goto error;\r
655 }\r
656 error = "file format error";\r
657 if ((b = read_body(fp)) == NULL)\r
658 goto error;\r
659 /* Select key algorithm structure. */\r
660 alg = find_pubkey_alg(b);\r
661 if (!alg) {\r
662 sfree(b);\r
663 goto error;\r
664 }\r
665 sfree(b);\r
666 \r
667 /* Read the Encryption header line. */\r
668 if (!read_header(fp, header) || 0 != strcmp(header, "Encryption"))\r
669 goto error;\r
670 if ((encryption = read_body(fp)) == NULL)\r
671 goto error;\r
672 if (!strcmp(encryption, "aes256-cbc")) {\r
673 cipher = 1;\r
674 cipherblk = 16;\r
675 } else if (!strcmp(encryption, "none")) {\r
676 cipher = 0;\r
677 cipherblk = 1;\r
678 } else {\r
679 sfree(encryption);\r
680 goto error;\r
681 }\r
682 \r
683 /* Read the Comment header line. */\r
684 if (!read_header(fp, header) || 0 != strcmp(header, "Comment"))\r
685 goto error;\r
686 if ((comment = read_body(fp)) == NULL)\r
687 goto error;\r
688 \r
689 /* Read the Public-Lines header line and the public blob. */\r
690 if (!read_header(fp, header) || 0 != strcmp(header, "Public-Lines"))\r
691 goto error;\r
692 if ((b = read_body(fp)) == NULL)\r
693 goto error;\r
694 i = atoi(b);\r
695 sfree(b);\r
696 if ((public_blob = read_blob(fp, i, &public_blob_len)) == NULL)\r
697 goto error;\r
698 \r
699 /* Read the Private-Lines header line and the Private blob. */\r
700 if (!read_header(fp, header) || 0 != strcmp(header, "Private-Lines"))\r
701 goto error;\r
702 if ((b = read_body(fp)) == NULL)\r
703 goto error;\r
704 i = atoi(b);\r
705 sfree(b);\r
706 if ((private_blob = read_blob(fp, i, &private_blob_len)) == NULL)\r
707 goto error;\r
708 \r
709 /* Read the Private-MAC or Private-Hash header line. */\r
710 if (!read_header(fp, header))\r
711 goto error;\r
712 if (0 == strcmp(header, "Private-MAC")) {\r
713 if ((mac = read_body(fp)) == NULL)\r
714 goto error;\r
715 is_mac = 1;\r
716 } else if (0 == strcmp(header, "Private-Hash") && old_fmt) {\r
717 if ((mac = read_body(fp)) == NULL)\r
718 goto error;\r
719 is_mac = 0;\r
720 } else\r
721 goto error;\r
722 \r
723 fclose(fp);\r
724 fp = NULL;\r
725 \r
726 /*\r
727 * Decrypt the private blob.\r
728 */\r
729 if (cipher) {\r
730 unsigned char key[40];\r
731 SHA_State s;\r
732 \r
733 if (!passphrase)\r
734 goto error;\r
735 if (private_blob_len % cipherblk)\r
736 goto error;\r
737 \r
738 SHA_Init(&s);\r
739 SHA_Bytes(&s, "\0\0\0\0", 4);\r
740 SHA_Bytes(&s, passphrase, passlen);\r
741 SHA_Final(&s, key + 0);\r
742 SHA_Init(&s);\r
743 SHA_Bytes(&s, "\0\0\0\1", 4);\r
744 SHA_Bytes(&s, passphrase, passlen);\r
745 SHA_Final(&s, key + 20);\r
746 aes256_decrypt_pubkey(key, private_blob, private_blob_len);\r
747 }\r
748 \r
749 /*\r
750 * Verify the MAC.\r
751 */\r
752 {\r
753 char realmac[41];\r
754 unsigned char binary[20];\r
755 unsigned char *macdata;\r
756 int maclen;\r
757 int free_macdata;\r
758 \r
759 if (old_fmt) {\r
760 /* MAC (or hash) only covers the private blob. */\r
761 macdata = private_blob;\r
762 maclen = private_blob_len;\r
763 free_macdata = 0;\r
764 } else {\r
765 unsigned char *p;\r
766 int namelen = strlen(alg->name);\r
767 int enclen = strlen(encryption);\r
768 int commlen = strlen(comment);\r
769 maclen = (4 + namelen +\r
770 4 + enclen +\r
771 4 + commlen +\r
772 4 + public_blob_len +\r
773 4 + private_blob_len);\r
774 macdata = snewn(maclen, unsigned char);\r
775 p = macdata;\r
776 #define DO_STR(s,len) PUT_32BIT(p,(len));memcpy(p+4,(s),(len));p+=4+(len)\r
777 DO_STR(alg->name, namelen);\r
778 DO_STR(encryption, enclen);\r
779 DO_STR(comment, commlen);\r
780 DO_STR(public_blob, public_blob_len);\r
781 DO_STR(private_blob, private_blob_len);\r
782 \r
783 free_macdata = 1;\r
784 }\r
785 \r
786 if (is_mac) {\r
787 SHA_State s;\r
788 unsigned char mackey[20];\r
789 char header[] = "putty-private-key-file-mac-key";\r
790 \r
791 SHA_Init(&s);\r
792 SHA_Bytes(&s, header, sizeof(header)-1);\r
793 if (cipher && passphrase)\r
794 SHA_Bytes(&s, passphrase, passlen);\r
795 SHA_Final(&s, mackey);\r
796 \r
797 hmac_sha1_simple(mackey, 20, macdata, maclen, binary);\r
798 \r
799 memset(mackey, 0, sizeof(mackey));\r
800 memset(&s, 0, sizeof(s));\r
801 } else {\r
802 SHA_Simple(macdata, maclen, binary);\r
803 }\r
804 \r
805 if (free_macdata) {\r
806 memset(macdata, 0, maclen);\r
807 sfree(macdata);\r
808 }\r
809 \r
810 for (i = 0; i < 20; i++)\r
811 sprintf(realmac + 2 * i, "%02x", binary[i]);\r
812 \r
813 if (strcmp(mac, realmac)) {\r
814 /* An incorrect MAC is an unconditional Error if the key is\r
815 * unencrypted. Otherwise, it means Wrong Passphrase. */\r
816 if (cipher) {\r
817 error = "wrong passphrase";\r
818 ret = SSH2_WRONG_PASSPHRASE;\r
819 } else {\r
820 error = "MAC failed";\r
821 ret = NULL;\r
822 }\r
823 goto error;\r
824 }\r
825 }\r
826 sfree(mac);\r
827 \r
828 /*\r
829 * Create and return the key.\r
830 */\r
831 ret = snew(struct ssh2_userkey);\r
832 ret->alg = alg;\r
833 ret->comment = comment;\r
834 ret->data = alg->createkey(public_blob, public_blob_len,\r
835 private_blob, private_blob_len);\r
836 if (!ret->data) {\r
837 sfree(ret->comment);\r
838 sfree(ret);\r
839 ret = NULL;\r
840 error = "createkey failed";\r
841 goto error;\r
842 }\r
843 sfree(public_blob);\r
844 sfree(private_blob);\r
845 sfree(encryption);\r
846 if (errorstr)\r
847 *errorstr = NULL;\r
848 return ret;\r
849 \r
850 /*\r
851 * Error processing.\r
852 */\r
853 error:\r
854 if (fp)\r
855 fclose(fp);\r
856 if (comment)\r
857 sfree(comment);\r
858 if (encryption)\r
859 sfree(encryption);\r
860 if (mac)\r
861 sfree(mac);\r
862 if (public_blob)\r
863 sfree(public_blob);\r
864 if (private_blob)\r
865 sfree(private_blob);\r
866 if (errorstr)\r
867 *errorstr = error;\r
868 return ret;\r
869 }\r
870 \r
871 unsigned char *ssh2_userkey_loadpub(const Filename *filename, char **algorithm,\r
872 int *pub_blob_len, char **commentptr,\r
873 const char **errorstr)\r
874 {\r
875 FILE *fp;\r
876 char header[40], *b;\r
877 const struct ssh_signkey *alg;\r
878 unsigned char *public_blob;\r
879 int public_blob_len;\r
880 int i;\r
881 const char *error = NULL;\r
882 char *comment;\r
883 \r
884 public_blob = NULL;\r
885 \r
886 fp = f_open(*filename, "rb", FALSE);\r
887 if (!fp) {\r
888 error = "can't open file";\r
889 goto error;\r
890 }\r
891 \r
892 /* Read the first header line which contains the key type. */\r
893 if (!read_header(fp, header)\r
894 || (0 != strcmp(header, "PuTTY-User-Key-File-2") &&\r
895 0 != strcmp(header, "PuTTY-User-Key-File-1"))) {\r
896 error = "not a PuTTY SSH-2 private key";\r
897 goto error;\r
898 }\r
899 error = "file format error";\r
900 if ((b = read_body(fp)) == NULL)\r
901 goto error;\r
902 /* Select key algorithm structure. */\r
903 alg = find_pubkey_alg(b);\r
904 if (!alg) {\r
905 sfree(b);\r
906 goto error;\r
907 }\r
908 sfree(b);\r
909 \r
910 /* Read the Encryption header line. */\r
911 if (!read_header(fp, header) || 0 != strcmp(header, "Encryption"))\r
912 goto error;\r
913 if ((b = read_body(fp)) == NULL)\r
914 goto error;\r
915 sfree(b); /* we don't care */\r
916 \r
917 /* Read the Comment header line. */\r
918 if (!read_header(fp, header) || 0 != strcmp(header, "Comment"))\r
919 goto error;\r
920 if ((comment = read_body(fp)) == NULL)\r
921 goto error;\r
922 \r
923 if (commentptr)\r
924 *commentptr = comment;\r
925 else\r
926 sfree(comment);\r
927 \r
928 /* Read the Public-Lines header line and the public blob. */\r
929 if (!read_header(fp, header) || 0 != strcmp(header, "Public-Lines"))\r
930 goto error;\r
931 if ((b = read_body(fp)) == NULL)\r
932 goto error;\r
933 i = atoi(b);\r
934 sfree(b);\r
935 if ((public_blob = read_blob(fp, i, &public_blob_len)) == NULL)\r
936 goto error;\r
937 \r
938 fclose(fp);\r
939 if (pub_blob_len)\r
940 *pub_blob_len = public_blob_len;\r
941 if (algorithm)\r
942 *algorithm = alg->name;\r
943 return public_blob;\r
944 \r
945 /*\r
946 * Error processing.\r
947 */\r
948 error:\r
949 if (fp)\r
950 fclose(fp);\r
951 if (public_blob)\r
952 sfree(public_blob);\r
953 if (errorstr)\r
954 *errorstr = error;\r
955 return NULL;\r
956 }\r
957 \r
958 int ssh2_userkey_encrypted(const Filename *filename, char **commentptr)\r
959 {\r
960 FILE *fp;\r
961 char header[40], *b, *comment;\r
962 int ret;\r
963 \r
964 if (commentptr)\r
965 *commentptr = NULL;\r
966 \r
967 fp = f_open(*filename, "rb", FALSE);\r
968 if (!fp)\r
969 return 0;\r
970 if (!read_header(fp, header)\r
971 || (0 != strcmp(header, "PuTTY-User-Key-File-2") &&\r
972 0 != strcmp(header, "PuTTY-User-Key-File-1"))) {\r
973 fclose(fp);\r
974 return 0;\r
975 }\r
976 if ((b = read_body(fp)) == NULL) {\r
977 fclose(fp);\r
978 return 0;\r
979 }\r
980 sfree(b); /* we don't care about key type here */\r
981 /* Read the Encryption header line. */\r
982 if (!read_header(fp, header) || 0 != strcmp(header, "Encryption")) {\r
983 fclose(fp);\r
984 return 0;\r
985 }\r
986 if ((b = read_body(fp)) == NULL) {\r
987 fclose(fp);\r
988 return 0;\r
989 }\r
990 \r
991 /* Read the Comment header line. */\r
992 if (!read_header(fp, header) || 0 != strcmp(header, "Comment")) {\r
993 fclose(fp);\r
994 sfree(b);\r
995 return 1;\r
996 }\r
997 if ((comment = read_body(fp)) == NULL) {\r
998 fclose(fp);\r
999 sfree(b);\r
1000 return 1;\r
1001 }\r
1002 \r
1003 if (commentptr)\r
1004 *commentptr = comment;\r
1005 \r
1006 fclose(fp);\r
1007 if (!strcmp(b, "aes256-cbc"))\r
1008 ret = 1;\r
1009 else\r
1010 ret = 0;\r
1011 sfree(b);\r
1012 return ret;\r
1013 }\r
1014 \r
1015 int base64_lines(int datalen)\r
1016 {\r
1017 /* When encoding, we use 64 chars/line, which equals 48 real chars. */\r
1018 return (datalen + 47) / 48;\r
1019 }\r
1020 \r
1021 void base64_encode(FILE * fp, unsigned char *data, int datalen, int cpl)\r
1022 {\r
1023 int linelen = 0;\r
1024 char out[4];\r
1025 int n, i;\r
1026 \r
1027 while (datalen > 0) {\r
1028 n = (datalen < 3 ? datalen : 3);\r
1029 base64_encode_atom(data, n, out);\r
1030 data += n;\r
1031 datalen -= n;\r
1032 for (i = 0; i < 4; i++) {\r
1033 if (linelen >= cpl) {\r
1034 linelen = 0;\r
1035 fputc('\n', fp);\r
1036 }\r
1037 fputc(out[i], fp);\r
1038 linelen++;\r
1039 }\r
1040 }\r
1041 fputc('\n', fp);\r
1042 }\r
1043 \r
1044 int ssh2_save_userkey(const Filename *filename, struct ssh2_userkey *key,\r
1045 char *passphrase)\r
1046 {\r
1047 FILE *fp;\r
1048 unsigned char *pub_blob, *priv_blob, *priv_blob_encrypted;\r
1049 int pub_blob_len, priv_blob_len, priv_encrypted_len;\r
1050 int passlen;\r
1051 int cipherblk;\r
1052 int i;\r
1053 char *cipherstr;\r
1054 unsigned char priv_mac[20];\r
1055 \r
1056 /*\r
1057 * Fetch the key component blobs.\r
1058 */\r
1059 pub_blob = key->alg->public_blob(key->data, &pub_blob_len);\r
1060 priv_blob = key->alg->private_blob(key->data, &priv_blob_len);\r
1061 if (!pub_blob || !priv_blob) {\r
1062 sfree(pub_blob);\r
1063 sfree(priv_blob);\r
1064 return 0;\r
1065 }\r
1066 \r
1067 /*\r
1068 * Determine encryption details, and encrypt the private blob.\r
1069 */\r
1070 if (passphrase) {\r
1071 cipherstr = "aes256-cbc";\r
1072 cipherblk = 16;\r
1073 } else {\r
1074 cipherstr = "none";\r
1075 cipherblk = 1;\r
1076 }\r
1077 priv_encrypted_len = priv_blob_len + cipherblk - 1;\r
1078 priv_encrypted_len -= priv_encrypted_len % cipherblk;\r
1079 priv_blob_encrypted = snewn(priv_encrypted_len, unsigned char);\r
1080 memset(priv_blob_encrypted, 0, priv_encrypted_len);\r
1081 memcpy(priv_blob_encrypted, priv_blob, priv_blob_len);\r
1082 /* Create padding based on the SHA hash of the unpadded blob. This prevents\r
1083 * too easy a known-plaintext attack on the last block. */\r
1084 SHA_Simple(priv_blob, priv_blob_len, priv_mac);\r
1085 assert(priv_encrypted_len - priv_blob_len < 20);\r
1086 memcpy(priv_blob_encrypted + priv_blob_len, priv_mac,\r
1087 priv_encrypted_len - priv_blob_len);\r
1088 \r
1089 /* Now create the MAC. */\r
1090 {\r
1091 unsigned char *macdata;\r
1092 int maclen;\r
1093 unsigned char *p;\r
1094 int namelen = strlen(key->alg->name);\r
1095 int enclen = strlen(cipherstr);\r
1096 int commlen = strlen(key->comment);\r
1097 SHA_State s;\r
1098 unsigned char mackey[20];\r
1099 char header[] = "putty-private-key-file-mac-key";\r
1100 \r
1101 maclen = (4 + namelen +\r
1102 4 + enclen +\r
1103 4 + commlen +\r
1104 4 + pub_blob_len +\r
1105 4 + priv_encrypted_len);\r
1106 macdata = snewn(maclen, unsigned char);\r
1107 p = macdata;\r
1108 #define DO_STR(s,len) PUT_32BIT(p,(len));memcpy(p+4,(s),(len));p+=4+(len)\r
1109 DO_STR(key->alg->name, namelen);\r
1110 DO_STR(cipherstr, enclen);\r
1111 DO_STR(key->comment, commlen);\r
1112 DO_STR(pub_blob, pub_blob_len);\r
1113 DO_STR(priv_blob_encrypted, priv_encrypted_len);\r
1114 \r
1115 SHA_Init(&s);\r
1116 SHA_Bytes(&s, header, sizeof(header)-1);\r
1117 if (passphrase)\r
1118 SHA_Bytes(&s, passphrase, strlen(passphrase));\r
1119 SHA_Final(&s, mackey);\r
1120 hmac_sha1_simple(mackey, 20, macdata, maclen, priv_mac);\r
1121 memset(macdata, 0, maclen);\r
1122 sfree(macdata);\r
1123 memset(mackey, 0, sizeof(mackey));\r
1124 memset(&s, 0, sizeof(s));\r
1125 }\r
1126 \r
1127 if (passphrase) {\r
1128 unsigned char key[40];\r
1129 SHA_State s;\r
1130 \r
1131 passlen = strlen(passphrase);\r
1132 \r
1133 SHA_Init(&s);\r
1134 SHA_Bytes(&s, "\0\0\0\0", 4);\r
1135 SHA_Bytes(&s, passphrase, passlen);\r
1136 SHA_Final(&s, key + 0);\r
1137 SHA_Init(&s);\r
1138 SHA_Bytes(&s, "\0\0\0\1", 4);\r
1139 SHA_Bytes(&s, passphrase, passlen);\r
1140 SHA_Final(&s, key + 20);\r
1141 aes256_encrypt_pubkey(key, priv_blob_encrypted,\r
1142 priv_encrypted_len);\r
1143 \r
1144 memset(key, 0, sizeof(key));\r
1145 memset(&s, 0, sizeof(s));\r
1146 }\r
1147 \r
1148 fp = f_open(*filename, "w", TRUE);\r
1149 if (!fp)\r
1150 return 0;\r
1151 fprintf(fp, "PuTTY-User-Key-File-2: %s\n", key->alg->name);\r
1152 fprintf(fp, "Encryption: %s\n", cipherstr);\r
1153 fprintf(fp, "Comment: %s\n", key->comment);\r
1154 fprintf(fp, "Public-Lines: %d\n", base64_lines(pub_blob_len));\r
1155 base64_encode(fp, pub_blob, pub_blob_len, 64);\r
1156 fprintf(fp, "Private-Lines: %d\n", base64_lines(priv_encrypted_len));\r
1157 base64_encode(fp, priv_blob_encrypted, priv_encrypted_len, 64);\r
1158 fprintf(fp, "Private-MAC: ");\r
1159 for (i = 0; i < 20; i++)\r
1160 fprintf(fp, "%02x", priv_mac[i]);\r
1161 fprintf(fp, "\n");\r
1162 fclose(fp);\r
1163 \r
1164 sfree(pub_blob);\r
1165 memset(priv_blob, 0, priv_blob_len);\r
1166 sfree(priv_blob);\r
1167 sfree(priv_blob_encrypted);\r
1168 return 1;\r
1169 }\r
1170 \r
1171 /* ----------------------------------------------------------------------\r
1172 * A function to determine the type of a private key file. Returns\r
1173 * 0 on failure, 1 or 2 on success.\r
1174 */\r
1175 int key_type(const Filename *filename)\r
1176 {\r
1177 FILE *fp;\r
1178 char buf[32];\r
1179 const char putty2_sig[] = "PuTTY-User-Key-File-";\r
1180 const char sshcom_sig[] = "---- BEGIN SSH2 ENCRYPTED PRIVAT";\r
1181 const char openssh_sig[] = "-----BEGIN ";\r
1182 int i;\r
1183 \r
1184 fp = f_open(*filename, "r", FALSE);\r
1185 if (!fp)\r
1186 return SSH_KEYTYPE_UNOPENABLE;\r
1187 i = fread(buf, 1, sizeof(buf), fp);\r
1188 fclose(fp);\r
1189 if (i < 0)\r
1190 return SSH_KEYTYPE_UNOPENABLE;\r
1191 if (i < 32)\r
1192 return SSH_KEYTYPE_UNKNOWN;\r
1193 if (!memcmp(buf, rsa_signature, sizeof(rsa_signature)-1))\r
1194 return SSH_KEYTYPE_SSH1;\r
1195 if (!memcmp(buf, putty2_sig, sizeof(putty2_sig)-1))\r
1196 return SSH_KEYTYPE_SSH2;\r
1197 if (!memcmp(buf, openssh_sig, sizeof(openssh_sig)-1))\r
1198 return SSH_KEYTYPE_OPENSSH;\r
1199 if (!memcmp(buf, sshcom_sig, sizeof(sshcom_sig)-1))\r
1200 return SSH_KEYTYPE_SSHCOM;\r
1201 return SSH_KEYTYPE_UNKNOWN; /* unrecognised or EOF */\r
1202 }\r
1203 \r
1204 /*\r
1205 * Convert the type word to a string, for `wrong type' error\r
1206 * messages.\r
1207 */\r
1208 char *key_type_to_str(int type)\r
1209 {\r
1210 switch (type) {\r
1211 case SSH_KEYTYPE_UNOPENABLE: return "unable to open file"; break;\r
1212 case SSH_KEYTYPE_UNKNOWN: return "not a private key"; break;\r
1213 case SSH_KEYTYPE_SSH1: return "SSH-1 private key"; break;\r
1214 case SSH_KEYTYPE_SSH2: return "PuTTY SSH-2 private key"; break;\r
1215 case SSH_KEYTYPE_OPENSSH: return "OpenSSH SSH-2 private key"; break;\r
1216 case SSH_KEYTYPE_SSHCOM: return "ssh.com SSH-2 private key"; break;\r
1217 default: return "INTERNAL ERROR"; break;\r
1218 }\r
1219 }\r