1 /* $OpenBSD: authfile.c,v 1.92 2011/06/14 22:49:18 markus Exp $ */
2 /*
3 * Author: Tatu Ylonen <ylo@cs.hut.fi>
4 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
5 * All rights reserved
6 * This file contains functions for reading and writing identity files, and
7 * for reading the passphrase from the user.
8 *
9 * As far as I am concerned, the code I have written for this software
10 * can be used freely for any purpose. Any derived versions of this
11 * software must be clearly marked as such, and if the derived work is
12 * incompatible with the protocol description in the RFC file, it must be
13 * called by a name other than "ssh" or "Secure Shell".
14 *
15 *
16 * Copyright (c) 2000 Markus Friedl. All rights reserved.
17 *
18 * Redistribution and use in source and binary forms, with or without
19 * modification, are permitted provided that the following conditions
20 * are met:
21 * 1. Redistributions of source code must retain the above copyright
22 * notice, this list of conditions and the following disclaimer.
23 * 2. Redistributions in binary form must reproduce the above copyright
24 * notice, this list of conditions and the following disclaimer in the
25 * documentation and/or other materials provided with the distribution.
26 *
27 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
28 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
29 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
30 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
31 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
32 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
33 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
34 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
35 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
36 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
37 */
38
39 #include "includes.h"
40
41 #include <sys/types.h>
42 #include <sys/stat.h>
43 #include <sys/param.h>
44 #include <sys/uio.h>
45
46 #include <openssl/err.h>
47 #include <openssl/evp.h>
48 #include <openssl/pem.h>
49
50 /* compatibility with old or broken OpenSSL versions */
51 #include "openbsd-compat/openssl-compat.h"
52
53 #include <errno.h>
54 #include <fcntl.h>
55 #include <stdarg.h>
56 #include <stdio.h>
57 #include <stdlib.h>
58 #include <string.h>
59 #include <unistd.h>
60
61 #include "xmalloc.h"
62 #include "cipher.h"
63 #include "buffer.h"
64 #include "key.h"
65 #include "ssh.h"
66 #include "log.h"
67 #include "authfile.h"
68 #include "rsa.h"
69 #include "misc.h"
70 #include "atomicio.h"
71
72 #define MAX_KEY_FILE_SIZE (1024 * 1024)
73
74 /* Version identification string for SSH v1 identity files. */
75 static const char authfile_id_string[] =
76 "SSH PRIVATE KEY FILE FORMAT 1.1\n";
77
78 /*
79 * Serialises the authentication (private) key to a blob, encrypting it with
80 * passphrase. The identification of the blob (lowest 64 bits of n) will
81 * precede the key to provide identification of the key without needing a
82 * passphrase.
83 */
84 static int
key_private_rsa1_to_blob(Key * key,Buffer * blob,const char * passphrase,const char * comment)85 key_private_rsa1_to_blob(Key *key, Buffer *blob, const char *passphrase,
86 const char *comment)
87 {
88 Buffer buffer, encrypted;
89 u_char buf[100], *cp;
90 int i, cipher_num;
91 CipherContext ciphercontext;
92 Cipher *cipher;
93 u_int32_t rnd;
94
95 /*
96 * If the passphrase is empty, use SSH_CIPHER_NONE to ease converting
97 * to another cipher; otherwise use SSH_AUTHFILE_CIPHER.
98 */
99 cipher_num = (strcmp(passphrase, "") == 0) ?
100 SSH_CIPHER_NONE : SSH_AUTHFILE_CIPHER;
101 if ((cipher = cipher_by_number(cipher_num)) == NULL)
102 fatal("save_private_key_rsa: bad cipher");
103
104 /* This buffer is used to built the secret part of the private key. */
105 buffer_init(&buffer);
106
107 /* Put checkbytes for checking passphrase validity. */
108 rnd = arc4random();
109 buf[0] = rnd & 0xff;
110 buf[1] = (rnd >> 8) & 0xff;
111 buf[2] = buf[0];
112 buf[3] = buf[1];
113 buffer_append(&buffer, buf, 4);
114
115 /*
116 * Store the private key (n and e will not be stored because they
117 * will be stored in plain text, and storing them also in encrypted
118 * format would just give known plaintext).
119 */
120 buffer_put_bignum(&buffer, key->rsa->d);
121 buffer_put_bignum(&buffer, key->rsa->iqmp);
122 buffer_put_bignum(&buffer, key->rsa->q); /* reverse from SSL p */
123 buffer_put_bignum(&buffer, key->rsa->p); /* reverse from SSL q */
124
125 /* Pad the part to be encrypted until its size is a multiple of 8. */
126 while (buffer_len(&buffer) % 8 != 0)
127 buffer_put_char(&buffer, 0);
128
129 /* This buffer will be used to contain the data in the file. */
130 buffer_init(&encrypted);
131
132 /* First store keyfile id string. */
133 for (i = 0; authfile_id_string[i]; i++)
134 buffer_put_char(&encrypted, authfile_id_string[i]);
135 buffer_put_char(&encrypted, 0);
136
137 /* Store cipher type. */
138 buffer_put_char(&encrypted, cipher_num);
139 buffer_put_int(&encrypted, 0); /* For future extension */
140
141 /* Store public key. This will be in plain text. */
142 buffer_put_int(&encrypted, BN_num_bits(key->rsa->n));
143 buffer_put_bignum(&encrypted, key->rsa->n);
144 buffer_put_bignum(&encrypted, key->rsa->e);
145 buffer_put_cstring(&encrypted, comment);
146
147 /* Allocate space for the private part of the key in the buffer. */
148 cp = buffer_append_space(&encrypted, buffer_len(&buffer));
149
150 cipher_set_key_string(&ciphercontext, cipher, passphrase,
151 CIPHER_ENCRYPT);
152 cipher_crypt(&ciphercontext, cp,
153 buffer_ptr(&buffer), buffer_len(&buffer));
154 cipher_cleanup(&ciphercontext);
155 memset(&ciphercontext, 0, sizeof(ciphercontext));
156
157 /* Destroy temporary data. */
158 memset(buf, 0, sizeof(buf));
159 buffer_free(&buffer);
160
161 buffer_append(blob, buffer_ptr(&encrypted), buffer_len(&encrypted));
162 buffer_free(&encrypted);
163
164 return 1;
165 }
166
167 /* convert SSH v2 key in OpenSSL PEM format */
168 static int
key_private_pem_to_blob(Key * key,Buffer * blob,const char * _passphrase,const char * comment)169 key_private_pem_to_blob(Key *key, Buffer *blob, const char *_passphrase,
170 const char *comment)
171 {
172 int success = 0;
173 int blen, len = strlen(_passphrase);
174 u_char *passphrase = (len > 0) ? (u_char *)_passphrase : NULL;
175 #if (OPENSSL_VERSION_NUMBER < 0x00907000L)
176 const EVP_CIPHER *cipher = (len > 0) ? EVP_des_ede3_cbc() : NULL;
177 #else
178 const EVP_CIPHER *cipher = (len > 0) ? EVP_aes_128_cbc() : NULL;
179 #endif
180 const u_char *bptr;
181 BIO *bio;
182
183 if (len > 0 && len <= 4) {
184 error("passphrase too short: have %d bytes, need > 4", len);
185 return 0;
186 }
187 if ((bio = BIO_new(BIO_s_mem())) == NULL) {
188 error("%s: BIO_new failed", __func__);
189 return 0;
190 }
191 switch (key->type) {
192 case KEY_DSA:
193 success = PEM_write_bio_DSAPrivateKey(bio, key->dsa,
194 cipher, passphrase, len, NULL, NULL);
195 break;
196 #ifdef OPENSSL_HAS_ECC
197 case KEY_ECDSA:
198 success = PEM_write_bio_ECPrivateKey(bio, key->ecdsa,
199 cipher, passphrase, len, NULL, NULL);
200 break;
201 #endif
202 case KEY_RSA:
203 success = PEM_write_bio_RSAPrivateKey(bio, key->rsa,
204 cipher, passphrase, len, NULL, NULL);
205 break;
206 }
207 if (success) {
208 if ((blen = BIO_get_mem_data(bio, &bptr)) <= 0)
209 success = 0;
210 else
211 buffer_append(blob, bptr, blen);
212 }
213 BIO_free(bio);
214 return success;
215 }
216
217 /* Save a key blob to a file */
218 static int
key_save_private_blob(Buffer * keybuf,const char * filename)219 key_save_private_blob(Buffer *keybuf, const char *filename)
220 {
221 int fd;
222
223 if ((fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0600)) < 0) {
224 error("open %s failed: %s.", filename, strerror(errno));
225 return 0;
226 }
227 if (atomicio(vwrite, fd, buffer_ptr(keybuf),
228 buffer_len(keybuf)) != buffer_len(keybuf)) {
229 error("write to key file %s failed: %s", filename,
230 strerror(errno));
231 close(fd);
232 unlink(filename);
233 return 0;
234 }
235 close(fd);
236 return 1;
237 }
238
239 /* Serialise "key" to buffer "blob" */
240 static int
key_private_to_blob(Key * key,Buffer * blob,const char * passphrase,const char * comment)241 key_private_to_blob(Key *key, Buffer *blob, const char *passphrase,
242 const char *comment)
243 {
244 switch (key->type) {
245 case KEY_RSA1:
246 return key_private_rsa1_to_blob(key, blob, passphrase, comment);
247 case KEY_DSA:
248 case KEY_ECDSA:
249 case KEY_RSA:
250 return key_private_pem_to_blob(key, blob, passphrase, comment);
251 default:
252 error("%s: cannot save key type %d", __func__, key->type);
253 return 0;
254 }
255 }
256
257 int
key_save_private(Key * key,const char * filename,const char * passphrase,const char * comment)258 key_save_private(Key *key, const char *filename, const char *passphrase,
259 const char *comment)
260 {
261 Buffer keyblob;
262 int success = 0;
263
264 buffer_init(&keyblob);
265 if (!key_private_to_blob(key, &keyblob, passphrase, comment))
266 goto out;
267 if (!key_save_private_blob(&keyblob, filename))
268 goto out;
269 success = 1;
270 out:
271 buffer_free(&keyblob);
272 return success;
273 }
274
275 /*
276 * Parse the public, unencrypted portion of a RSA1 key.
277 */
278 static Key *
key_parse_public_rsa1(Buffer * blob,char ** commentp)279 key_parse_public_rsa1(Buffer *blob, char **commentp)
280 {
281 Key *pub;
282 Buffer copy;
283
284 /* Check that it is at least big enough to contain the ID string. */
285 if (buffer_len(blob) < sizeof(authfile_id_string)) {
286 debug3("Truncated RSA1 identifier");
287 return NULL;
288 }
289
290 /*
291 * Make sure it begins with the id string. Consume the id string
292 * from the buffer.
293 */
294 if (memcmp(buffer_ptr(blob), authfile_id_string,
295 sizeof(authfile_id_string)) != 0) {
296 debug3("Incorrect RSA1 identifier");
297 return NULL;
298 }
299 buffer_init(©);
300 buffer_append(©, buffer_ptr(blob), buffer_len(blob));
301 buffer_consume(©, sizeof(authfile_id_string));
302
303 /* Skip cipher type and reserved data. */
304 (void) buffer_get_char(©); /* cipher type */
305 (void) buffer_get_int(©); /* reserved */
306
307 /* Read the public key from the buffer. */
308 (void) buffer_get_int(©);
309 pub = key_new(KEY_RSA1);
310 buffer_get_bignum(©, pub->rsa->n);
311 buffer_get_bignum(©, pub->rsa->e);
312 if (commentp)
313 *commentp = buffer_get_string(©, NULL);
314 /* The encrypted private part is not parsed by this function. */
315 buffer_free(©);
316
317 return pub;
318 }
319
320 /* Load a key from a fd into a buffer */
321 int
key_load_file(int fd,const char * filename,Buffer * blob)322 key_load_file(int fd, const char *filename, Buffer *blob)
323 {
324 u_char buf[1024];
325 size_t len;
326 struct stat st;
327
328 if (fstat(fd, &st) < 0) {
329 error("%s: fstat of key file %.200s%sfailed: %.100s", __func__,
330 filename == NULL ? "" : filename,
331 filename == NULL ? "" : " ",
332 strerror(errno));
333 return 0;
334 }
335 if ((st.st_mode & (S_IFSOCK|S_IFCHR|S_IFIFO)) == 0 &&
336 st.st_size > MAX_KEY_FILE_SIZE) {
337 toobig:
338 error("%s: key file %.200s%stoo large", __func__,
339 filename == NULL ? "" : filename,
340 filename == NULL ? "" : " ");
341 return 0;
342 }
343 buffer_init(blob);
344 for (;;) {
345 if ((len = atomicio(read, fd, buf, sizeof(buf))) == 0) {
346 if (errno == EPIPE)
347 break;
348 debug("%s: read from key file %.200s%sfailed: %.100s",
349 __func__, filename == NULL ? "" : filename,
350 filename == NULL ? "" : " ", strerror(errno));
351 buffer_clear(blob);
352 bzero(buf, sizeof(buf));
353 return 0;
354 }
355 buffer_append(blob, buf, len);
356 if (buffer_len(blob) > MAX_KEY_FILE_SIZE) {
357 buffer_clear(blob);
358 bzero(buf, sizeof(buf));
359 goto toobig;
360 }
361 }
362 bzero(buf, sizeof(buf));
363 if ((st.st_mode & (S_IFSOCK|S_IFCHR|S_IFIFO)) == 0 &&
364 st.st_size != buffer_len(blob)) {
365 debug("%s: key file %.200s%schanged size while reading",
366 __func__, filename == NULL ? "" : filename,
367 filename == NULL ? "" : " ");
368 buffer_clear(blob);
369 return 0;
370 }
371
372 return 1;
373 }
374
375 /*
376 * Loads the public part of the ssh v1 key file. Returns NULL if an error was
377 * encountered (the file does not exist or is not readable), and the key
378 * otherwise.
379 */
380 static Key *
key_load_public_rsa1(int fd,const char * filename,char ** commentp)381 key_load_public_rsa1(int fd, const char *filename, char **commentp)
382 {
383 Buffer buffer;
384 Key *pub;
385
386 buffer_init(&buffer);
387 if (!key_load_file(fd, filename, &buffer)) {
388 buffer_free(&buffer);
389 return NULL;
390 }
391
392 pub = key_parse_public_rsa1(&buffer, commentp);
393 if (pub == NULL)
394 debug3("Could not load \"%s\" as a RSA1 public key", filename);
395 buffer_free(&buffer);
396 return pub;
397 }
398
399 /* load public key from private-key file, works only for SSH v1 */
400 Key *
key_load_public_type(int type,const char * filename,char ** commentp)401 key_load_public_type(int type, const char *filename, char **commentp)
402 {
403 Key *pub;
404 int fd;
405
406 if (type == KEY_RSA1) {
407 fd = open(filename, O_RDONLY);
408 if (fd < 0)
409 return NULL;
410 pub = key_load_public_rsa1(fd, filename, commentp);
411 close(fd);
412 return pub;
413 }
414 return NULL;
415 }
416
417 static Key *
key_parse_private_rsa1(Buffer * blob,const char * passphrase,char ** commentp)418 key_parse_private_rsa1(Buffer *blob, const char *passphrase, char **commentp)
419 {
420 int check1, check2, cipher_type;
421 Buffer decrypted;
422 u_char *cp;
423 CipherContext ciphercontext;
424 Cipher *cipher;
425 Key *prv = NULL;
426 Buffer copy;
427
428 /* Check that it is at least big enough to contain the ID string. */
429 if (buffer_len(blob) < sizeof(authfile_id_string)) {
430 debug3("Truncated RSA1 identifier");
431 return NULL;
432 }
433
434 /*
435 * Make sure it begins with the id string. Consume the id string
436 * from the buffer.
437 */
438 if (memcmp(buffer_ptr(blob), authfile_id_string,
439 sizeof(authfile_id_string)) != 0) {
440 debug3("Incorrect RSA1 identifier");
441 return NULL;
442 }
443 buffer_init(©);
444 buffer_append(©, buffer_ptr(blob), buffer_len(blob));
445 buffer_consume(©, sizeof(authfile_id_string));
446
447 /* Read cipher type. */
448 cipher_type = buffer_get_char(©);
449 (void) buffer_get_int(©); /* Reserved data. */
450
451 /* Read the public key from the buffer. */
452 (void) buffer_get_int(©);
453 prv = key_new_private(KEY_RSA1);
454
455 buffer_get_bignum(©, prv->rsa->n);
456 buffer_get_bignum(©, prv->rsa->e);
457 if (commentp)
458 *commentp = buffer_get_string(©, NULL);
459 else
460 (void)buffer_get_string_ptr(©, NULL);
461
462 /* Check that it is a supported cipher. */
463 cipher = cipher_by_number(cipher_type);
464 if (cipher == NULL) {
465 debug("Unsupported RSA1 cipher %d", cipher_type);
466 buffer_free(©);
467 goto fail;
468 }
469 /* Initialize space for decrypted data. */
470 buffer_init(&decrypted);
471 cp = buffer_append_space(&decrypted, buffer_len(©));
472
473 /* Rest of the buffer is encrypted. Decrypt it using the passphrase. */
474 cipher_set_key_string(&ciphercontext, cipher, passphrase,
475 CIPHER_DECRYPT);
476 cipher_crypt(&ciphercontext, cp,
477 buffer_ptr(©), buffer_len(©));
478 cipher_cleanup(&ciphercontext);
479 memset(&ciphercontext, 0, sizeof(ciphercontext));
480 buffer_free(©);
481
482 check1 = buffer_get_char(&decrypted);
483 check2 = buffer_get_char(&decrypted);
484 if (check1 != buffer_get_char(&decrypted) ||
485 check2 != buffer_get_char(&decrypted)) {
486 if (strcmp(passphrase, "") != 0)
487 debug("Bad passphrase supplied for RSA1 key");
488 /* Bad passphrase. */
489 buffer_free(&decrypted);
490 goto fail;
491 }
492 /* Read the rest of the private key. */
493 buffer_get_bignum(&decrypted, prv->rsa->d);
494 buffer_get_bignum(&decrypted, prv->rsa->iqmp); /* u */
495 /* in SSL and SSH v1 p and q are exchanged */
496 buffer_get_bignum(&decrypted, prv->rsa->q); /* p */
497 buffer_get_bignum(&decrypted, prv->rsa->p); /* q */
498
499 /* calculate p-1 and q-1 */
500 rsa_generate_additional_parameters(prv->rsa);
501
502 buffer_free(&decrypted);
503
504 /* enable blinding */
505 if (RSA_blinding_on(prv->rsa, NULL) != 1) {
506 error("%s: RSA_blinding_on failed", __func__);
507 goto fail;
508 }
509 return prv;
510
511 fail:
512 if (commentp)
513 xfree(*commentp);
514 key_free(prv);
515 return NULL;
516 }
517
518 static Key *
key_parse_private_pem(Buffer * blob,int type,const char * passphrase,char ** commentp)519 key_parse_private_pem(Buffer *blob, int type, const char *passphrase,
520 char **commentp)
521 {
522 EVP_PKEY *pk = NULL;
523 Key *prv = NULL;
524 char *name = "<no key>";
525 BIO *bio;
526
527 if ((bio = BIO_new_mem_buf(buffer_ptr(blob),
528 buffer_len(blob))) == NULL) {
529 error("%s: BIO_new_mem_buf failed", __func__);
530 return NULL;
531 }
532
533 pk = PEM_read_bio_PrivateKey(bio, NULL, NULL, (char *)passphrase);
534 BIO_free(bio);
535 if (pk == NULL) {
536 debug("%s: PEM_read_PrivateKey failed", __func__);
537 (void)ERR_get_error();
538 } else if (pk->type == EVP_PKEY_RSA &&
539 (type == KEY_UNSPEC||type==KEY_RSA)) {
540 prv = key_new(KEY_UNSPEC);
541 prv->rsa = EVP_PKEY_get1_RSA(pk);
542 prv->type = KEY_RSA;
543 name = "rsa w/o comment";
544 #ifdef DEBUG_PK
545 RSA_print_fp(stderr, prv->rsa, 8);
546 #endif
547 if (RSA_blinding_on(prv->rsa, NULL) != 1) {
548 error("%s: RSA_blinding_on failed", __func__);
549 key_free(prv);
550 prv = NULL;
551 }
552 } else if (pk->type == EVP_PKEY_DSA &&
553 (type == KEY_UNSPEC||type==KEY_DSA)) {
554 prv = key_new(KEY_UNSPEC);
555 prv->dsa = EVP_PKEY_get1_DSA(pk);
556 prv->type = KEY_DSA;
557 name = "dsa w/o comment";
558 #ifdef DEBUG_PK
559 DSA_print_fp(stderr, prv->dsa, 8);
560 #endif
561 #ifdef OPENSSL_HAS_ECC
562 } else if (pk->type == EVP_PKEY_EC &&
563 (type == KEY_UNSPEC||type==KEY_ECDSA)) {
564 prv = key_new(KEY_UNSPEC);
565 prv->ecdsa = EVP_PKEY_get1_EC_KEY(pk);
566 prv->type = KEY_ECDSA;
567 if ((prv->ecdsa_nid = key_ecdsa_key_to_nid(prv->ecdsa)) == -1 ||
568 key_curve_nid_to_name(prv->ecdsa_nid) == NULL ||
569 key_ec_validate_public(EC_KEY_get0_group(prv->ecdsa),
570 EC_KEY_get0_public_key(prv->ecdsa)) != 0 ||
571 key_ec_validate_private(prv->ecdsa) != 0) {
572 error("%s: bad ECDSA key", __func__);
573 key_free(prv);
574 prv = NULL;
575 }
576 name = "ecdsa w/o comment";
577 #ifdef DEBUG_PK
578 if (prv != NULL && prv->ecdsa != NULL)
579 key_dump_ec_key(prv->ecdsa);
580 #endif
581 #endif /* OPENSSL_HAS_ECC */
582 } else {
583 error("%s: PEM_read_PrivateKey: mismatch or "
584 "unknown EVP_PKEY save_type %d", __func__, pk->save_type);
585 }
586 if (pk != NULL)
587 EVP_PKEY_free(pk);
588 if (prv != NULL && commentp)
589 *commentp = xstrdup(name);
590 debug("read PEM private key done: type %s",
591 prv ? key_type(prv) : "<unknown>");
592 return prv;
593 }
594
595 Key *
key_load_private_pem(int fd,int type,const char * passphrase,char ** commentp)596 key_load_private_pem(int fd, int type, const char *passphrase,
597 char **commentp)
598 {
599 Buffer buffer;
600 Key *prv;
601
602 buffer_init(&buffer);
603 if (!key_load_file(fd, NULL, &buffer)) {
604 buffer_free(&buffer);
605 return NULL;
606 }
607 prv = key_parse_private_pem(&buffer, type, passphrase, commentp);
608 buffer_free(&buffer);
609 return prv;
610 }
611
612 int
key_perm_ok(int fd,const char * filename)613 key_perm_ok(int fd, const char *filename)
614 {
615 struct stat st;
616
617 if (fstat(fd, &st) < 0)
618 return 0;
619 /*
620 * if a key owned by the user is accessed, then we check the
621 * permissions of the file. if the key owned by a different user,
622 * then we don't care.
623 */
624 #ifdef HAVE_CYGWIN
625 if (check_ntsec(filename))
626 #endif
627 if ((st.st_uid == getuid()) && (st.st_mode & 077) != 0) {
628 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
629 error("@ WARNING: UNPROTECTED PRIVATE KEY FILE! @");
630 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
631 error("Permissions 0%3.3o for '%s' are too open.",
632 (u_int)st.st_mode & 0777, filename);
633 error("It is required that your private key files are NOT accessible by others.");
634 error("This private key will be ignored.");
635 return 0;
636 }
637 return 1;
638 }
639
640 static Key *
key_parse_private_type(Buffer * blob,int type,const char * passphrase,char ** commentp)641 key_parse_private_type(Buffer *blob, int type, const char *passphrase,
642 char **commentp)
643 {
644 switch (type) {
645 case KEY_RSA1:
646 return key_parse_private_rsa1(blob, passphrase, commentp);
647 case KEY_DSA:
648 case KEY_ECDSA:
649 case KEY_RSA:
650 case KEY_UNSPEC:
651 return key_parse_private_pem(blob, type, passphrase, commentp);
652 default:
653 error("%s: cannot parse key type %d", __func__, type);
654 break;
655 }
656 return NULL;
657 }
658
659 Key *
key_load_private_type(int type,const char * filename,const char * passphrase,char ** commentp,int * perm_ok)660 key_load_private_type(int type, const char *filename, const char *passphrase,
661 char **commentp, int *perm_ok)
662 {
663 int fd;
664 Key *ret;
665 Buffer buffer;
666
667 fd = open(filename, O_RDONLY);
668 if (fd < 0) {
669 debug("could not open key file '%s': %s", filename,
670 strerror(errno));
671 if (perm_ok != NULL)
672 *perm_ok = 0;
673 return NULL;
674 }
675 if (!key_perm_ok(fd, filename)) {
676 if (perm_ok != NULL)
677 *perm_ok = 0;
678 error("bad permissions: ignore key: %s", filename);
679 close(fd);
680 return NULL;
681 }
682 if (perm_ok != NULL)
683 *perm_ok = 1;
684
685 buffer_init(&buffer);
686 if (!key_load_file(fd, filename, &buffer)) {
687 buffer_free(&buffer);
688 close(fd);
689 return NULL;
690 }
691 close(fd);
692 ret = key_parse_private_type(&buffer, type, passphrase, commentp);
693 buffer_free(&buffer);
694 return ret;
695 }
696
697 Key *
key_parse_private(Buffer * buffer,const char * filename,const char * passphrase,char ** commentp)698 key_parse_private(Buffer *buffer, const char *filename,
699 const char *passphrase, char **commentp)
700 {
701 Key *pub, *prv;
702
703 /* it's a SSH v1 key if the public key part is readable */
704 pub = key_parse_public_rsa1(buffer, commentp);
705 if (pub == NULL) {
706 prv = key_parse_private_type(buffer, KEY_UNSPEC,
707 passphrase, NULL);
708 /* use the filename as a comment for PEM */
709 if (commentp && prv)
710 *commentp = xstrdup(filename);
711 } else {
712 key_free(pub);
713 /* key_parse_public_rsa1() has already loaded the comment */
714 prv = key_parse_private_type(buffer, KEY_RSA1, passphrase,
715 NULL);
716 }
717 return prv;
718 }
719
720 Key *
key_load_private(const char * filename,const char * passphrase,char ** commentp)721 key_load_private(const char *filename, const char *passphrase,
722 char **commentp)
723 {
724 Key *prv;
725 Buffer buffer;
726 int fd;
727
728 fd = open(filename, O_RDONLY);
729 if (fd < 0) {
730 debug("could not open key file '%s': %s", filename,
731 strerror(errno));
732 return NULL;
733 }
734 if (!key_perm_ok(fd, filename)) {
735 error("bad permissions: ignore key: %s", filename);
736 close(fd);
737 return NULL;
738 }
739
740 buffer_init(&buffer);
741 if (!key_load_file(fd, filename, &buffer)) {
742 buffer_free(&buffer);
743 close(fd);
744 return NULL;
745 }
746 close(fd);
747
748 prv = key_parse_private(&buffer, filename, passphrase, commentp);
749 buffer_free(&buffer);
750 return prv;
751 }
752
753 static int
key_try_load_public(Key * k,const char * filename,char ** commentp)754 key_try_load_public(Key *k, const char *filename, char **commentp)
755 {
756 FILE *f;
757 char line[SSH_MAX_PUBKEY_BYTES];
758 char *cp;
759 u_long linenum = 0;
760
761 f = fopen(filename, "r");
762 if (f != NULL) {
763 while (read_keyfile_line(f, filename, line, sizeof(line),
764 &linenum) != -1) {
765 cp = line;
766 switch (*cp) {
767 case '#':
768 case '\n':
769 case '\0':
770 continue;
771 }
772 /* Abort loading if this looks like a private key */
773 if (strncmp(cp, "-----BEGIN", 10) == 0)
774 break;
775 /* Skip leading whitespace. */
776 for (; *cp && (*cp == ' ' || *cp == '\t'); cp++)
777 ;
778 if (*cp) {
779 if (key_read(k, &cp) == 1) {
780 cp[strcspn(cp, "\r\n")] = '\0';
781 if (commentp) {
782 *commentp = xstrdup(*cp ?
783 cp : filename);
784 }
785 fclose(f);
786 return 1;
787 }
788 }
789 }
790 fclose(f);
791 }
792 return 0;
793 }
794
795 /* load public key from ssh v1 private or any pubkey file */
796 Key *
key_load_public(const char * filename,char ** commentp)797 key_load_public(const char *filename, char **commentp)
798 {
799 Key *pub;
800 char file[MAXPATHLEN];
801
802 /* try rsa1 private key */
803 pub = key_load_public_type(KEY_RSA1, filename, commentp);
804 if (pub != NULL)
805 return pub;
806
807 /* try rsa1 public key */
808 pub = key_new(KEY_RSA1);
809 if (key_try_load_public(pub, filename, commentp) == 1)
810 return pub;
811 key_free(pub);
812
813 /* try ssh2 public key */
814 pub = key_new(KEY_UNSPEC);
815 if (key_try_load_public(pub, filename, commentp) == 1)
816 return pub;
817 if ((strlcpy(file, filename, sizeof file) < sizeof(file)) &&
818 (strlcat(file, ".pub", sizeof file) < sizeof(file)) &&
819 (key_try_load_public(pub, file, commentp) == 1))
820 return pub;
821 key_free(pub);
822 return NULL;
823 }
824
825 /* Load the certificate associated with the named private key */
826 Key *
key_load_cert(const char * filename)827 key_load_cert(const char *filename)
828 {
829 Key *pub;
830 char *file;
831
832 pub = key_new(KEY_UNSPEC);
833 xasprintf(&file, "%s-cert.pub", filename);
834 if (key_try_load_public(pub, file, NULL) == 1) {
835 xfree(file);
836 return pub;
837 }
838 xfree(file);
839 key_free(pub);
840 return NULL;
841 }
842
843 /* Load private key and certificate */
844 Key *
key_load_private_cert(int type,const char * filename,const char * passphrase,int * perm_ok)845 key_load_private_cert(int type, const char *filename, const char *passphrase,
846 int *perm_ok)
847 {
848 Key *key, *pub;
849
850 switch (type) {
851 case KEY_RSA:
852 case KEY_DSA:
853 case KEY_ECDSA:
854 break;
855 default:
856 error("%s: unsupported key type", __func__);
857 return NULL;
858 }
859
860 if ((key = key_load_private_type(type, filename,
861 passphrase, NULL, perm_ok)) == NULL)
862 return NULL;
863
864 if ((pub = key_load_cert(filename)) == NULL) {
865 key_free(key);
866 return NULL;
867 }
868
869 /* Make sure the private key matches the certificate */
870 if (key_equal_public(key, pub) == 0) {
871 error("%s: certificate does not match private key %s",
872 __func__, filename);
873 } else if (key_to_certified(key, key_cert_is_legacy(pub)) != 0) {
874 error("%s: key_to_certified failed", __func__);
875 } else {
876 key_cert_copy(pub, key);
877 key_free(pub);
878 return key;
879 }
880
881 key_free(key);
882 key_free(pub);
883 return NULL;
884 }
885
886 /*
887 * Returns 1 if the specified "key" is listed in the file "filename",
888 * 0 if the key is not listed or -1 on error.
889 * If strict_type is set then the key type must match exactly,
890 * otherwise a comparison that ignores certficiate data is performed.
891 */
892 int
key_in_file(Key * key,const char * filename,int strict_type)893 key_in_file(Key *key, const char *filename, int strict_type)
894 {
895 FILE *f;
896 char line[SSH_MAX_PUBKEY_BYTES];
897 char *cp;
898 u_long linenum = 0;
899 int ret = 0;
900 Key *pub;
901 int (*key_compare)(const Key *, const Key *) = strict_type ?
902 key_equal : key_equal_public;
903
904 if ((f = fopen(filename, "r")) == NULL) {
905 if (errno == ENOENT) {
906 debug("%s: keyfile \"%s\" missing", __func__, filename);
907 return 0;
908 } else {
909 error("%s: could not open keyfile \"%s\": %s", __func__,
910 filename, strerror(errno));
911 return -1;
912 }
913 }
914
915 while (read_keyfile_line(f, filename, line, sizeof(line),
916 &linenum) != -1) {
917 cp = line;
918
919 /* Skip leading whitespace. */
920 for (; *cp && (*cp == ' ' || *cp == '\t'); cp++)
921 ;
922
923 /* Skip comments and empty lines */
924 switch (*cp) {
925 case '#':
926 case '\n':
927 case '\0':
928 continue;
929 }
930
931 pub = key_new(KEY_UNSPEC);
932 if (key_read(pub, &cp) != 1) {
933 key_free(pub);
934 continue;
935 }
936 if (key_compare(key, pub)) {
937 ret = 1;
938 key_free(pub);
939 break;
940 }
941 key_free(pub);
942 }
943 fclose(f);
944 return ret;
945 }
946
947