2 * Author: Tatu Ylonen <ylo@cs.hut.fi>
3 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
5 * This file contains functions for reading and writing identity files, and
6 * for reading the passphrase from the user.
8 * As far as I am concerned, the code I have written for this software
9 * can be used freely for any purpose. Any derived versions of this
10 * software must be clearly marked as such, and if the derived work is
11 * incompatible with the protocol description in the RFC file, it must be
12 * called by a name other than "ssh" or "Secure Shell".
15 * Copyright (c) 2000 Markus Friedl. All rights reserved.
17 * Redistribution and use in source and binary forms, with or without
18 * modification, are permitted provided that the following conditions
20 * 1. Redistributions of source code must retain the above copyright
21 * notice, this list of conditions and the following disclaimer.
22 * 2. Redistributions in binary form must reproduce the above copyright
23 * notice, this list of conditions and the following disclaimer in the
24 * documentation and/or other materials provided with the distribution.
26 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
27 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
28 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
29 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
30 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
31 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
32 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
33 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
34 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
35 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
39 RCSID("$OpenBSD: authfile.c,v 1.57 2004/06/21 17:36:31 avsm Exp $");
41 #include <openssl/err.h>
42 #include <openssl/evp.h>
43 #include <openssl/pem.h>
55 /* Version identification string for SSH v1 identity files. */
56 static const char authfile_id_string[] =
57 "SSH PRIVATE KEY FILE FORMAT 1.1\n";
60 * Saves the authentication (private) key in a file, encrypting it with
61 * passphrase. The identification of the file (lowest 64 bits of n) will
62 * precede the key to provide identification of the key without needing a
67 key_save_private_rsa1(Key *key, const char *filename, const char *passphrase,
70 Buffer buffer, encrypted;
72 int fd, i, cipher_num;
73 CipherContext ciphercontext;
78 * If the passphrase is empty, use SSH_CIPHER_NONE to ease converting
79 * to another cipher; otherwise use SSH_AUTHFILE_CIPHER.
81 cipher_num = (strcmp(passphrase, "") == 0) ?
82 SSH_CIPHER_NONE : SSH_AUTHFILE_CIPHER;
83 if ((cipher = cipher_by_number(cipher_num)) == NULL)
84 fatal("save_private_key_rsa: bad cipher");
86 /* This buffer is used to built the secret part of the private key. */
89 /* Put checkbytes for checking passphrase validity. */
92 buf[1] = (rnd >> 8) & 0xff;
95 buffer_append(&buffer, buf, 4);
98 * Store the private key (n and e will not be stored because they
99 * will be stored in plain text, and storing them also in encrypted
100 * format would just give known plaintext).
102 buffer_put_bignum(&buffer, key->rsa->d);
103 buffer_put_bignum(&buffer, key->rsa->iqmp);
104 buffer_put_bignum(&buffer, key->rsa->q); /* reverse from SSL p */
105 buffer_put_bignum(&buffer, key->rsa->p); /* reverse from SSL q */
107 /* Pad the part to be encrypted until its size is a multiple of 8. */
108 while (buffer_len(&buffer) % 8 != 0)
109 buffer_put_char(&buffer, 0);
111 /* This buffer will be used to contain the data in the file. */
112 buffer_init(&encrypted);
114 /* First store keyfile id string. */
115 for (i = 0; authfile_id_string[i]; i++)
116 buffer_put_char(&encrypted, authfile_id_string[i]);
117 buffer_put_char(&encrypted, 0);
119 /* Store cipher type. */
120 buffer_put_char(&encrypted, cipher_num);
121 buffer_put_int(&encrypted, 0); /* For future extension */
123 /* Store public key. This will be in plain text. */
124 buffer_put_int(&encrypted, BN_num_bits(key->rsa->n));
125 buffer_put_bignum(&encrypted, key->rsa->n);
126 buffer_put_bignum(&encrypted, key->rsa->e);
127 buffer_put_cstring(&encrypted, comment);
129 /* Allocate space for the private part of the key in the buffer. */
130 cp = buffer_append_space(&encrypted, buffer_len(&buffer));
132 cipher_set_key_string(&ciphercontext, cipher, passphrase,
134 cipher_crypt(&ciphercontext, cp,
135 buffer_ptr(&buffer), buffer_len(&buffer));
136 cipher_cleanup(&ciphercontext);
137 memset(&ciphercontext, 0, sizeof(ciphercontext));
139 /* Destroy temporary data. */
140 memset(buf, 0, sizeof(buf));
141 buffer_free(&buffer);
143 fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0600);
145 error("open %s failed: %s.", filename, strerror(errno));
146 buffer_free(&encrypted);
149 if (write(fd, buffer_ptr(&encrypted), buffer_len(&encrypted)) !=
150 buffer_len(&encrypted)) {
151 error("write to key file %s failed: %s", filename,
153 buffer_free(&encrypted);
159 buffer_free(&encrypted);
163 /* save SSH v2 key in OpenSSL PEM format */
165 key_save_private_pem(Key *key, const char *filename, const char *_passphrase,
171 int len = strlen(_passphrase);
172 u_char *passphrase = (len > 0) ? (u_char *)_passphrase : NULL;
173 const EVP_CIPHER *cipher = (len > 0) ? EVP_des_ede3_cbc() : NULL;
175 if (len > 0 && len <= 4) {
176 error("passphrase too short: have %d bytes, need > 4", len);
179 fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0600);
181 error("open %s failed: %s.", filename, strerror(errno));
184 fp = fdopen(fd, "w");
186 error("fdopen %s failed: %s.", filename, strerror(errno));
192 success = PEM_write_DSAPrivateKey(fp, key->dsa,
193 cipher, passphrase, len, NULL, NULL);
196 success = PEM_write_RSAPrivateKey(fp, key->rsa,
197 cipher, passphrase, len, NULL, NULL);
205 key_save_private(Key *key, const char *filename, const char *passphrase,
210 return key_save_private_rsa1(key, filename, passphrase,
215 return key_save_private_pem(key, filename, passphrase,
221 error("key_save_private: cannot save key type %d", key->type);
226 * Loads the public part of the ssh v1 key file. Returns NULL if an error was
227 * encountered (the file does not exist or is not readable), and the key
232 key_load_public_rsa1(int fd, const char *filename, char **commentp)
241 if (fstat(fd, &st) < 0) {
242 error("fstat for key file %.200s failed: %.100s",
243 filename, strerror(errno));
246 if (st.st_size > 1*1024*1024)
248 len = (size_t)st.st_size; /* truncated */
250 buffer_init(&buffer);
251 cp = buffer_append_space(&buffer, len);
253 if (read(fd, cp, (size_t) len) != (size_t) len) {
254 debug("Read from key file %.200s failed: %.100s", filename,
256 buffer_free(&buffer);
260 /* Check that it is at least big enough to contain the ID string. */
261 if (len < sizeof(authfile_id_string)) {
262 debug3("Not a RSA1 key file %.200s.", filename);
263 buffer_free(&buffer);
267 * Make sure it begins with the id string. Consume the id string
270 for (i = 0; i < sizeof(authfile_id_string); i++)
271 if (buffer_get_char(&buffer) != authfile_id_string[i]) {
272 debug3("Not a RSA1 key file %.200s.", filename);
273 buffer_free(&buffer);
276 /* Skip cipher type and reserved data. */
277 (void) buffer_get_char(&buffer); /* cipher type */
278 (void) buffer_get_int(&buffer); /* reserved */
280 /* Read the public key from the buffer. */
281 (void) buffer_get_int(&buffer);
282 pub = key_new(KEY_RSA1);
283 buffer_get_bignum(&buffer, pub->rsa->n);
284 buffer_get_bignum(&buffer, pub->rsa->e);
286 *commentp = buffer_get_string(&buffer, NULL);
287 /* The encrypted private part is not parsed by this function. */
289 buffer_free(&buffer);
293 /* load public key from private-key file, works only for SSH v1 */
295 key_load_public_type(int type, const char *filename, char **commentp)
300 if (type == KEY_RSA1) {
301 fd = open(filename, O_RDONLY);
304 pub = key_load_public_rsa1(fd, filename, commentp);
312 * Loads the private key from the file. Returns 0 if an error is encountered
313 * (file does not exist or is not readable, or passphrase is bad). This
314 * initializes the private key.
315 * Assumes we are called under uid of the owner of the file.
319 key_load_private_rsa1(int fd, const char *filename, const char *passphrase,
322 int i, check1, check2, cipher_type;
324 Buffer buffer, decrypted;
326 CipherContext ciphercontext;
331 if (fstat(fd, &st) < 0) {
332 error("fstat for key file %.200s failed: %.100s",
333 filename, strerror(errno));
337 if (st.st_size > 1*1024*1024) {
341 len = (size_t)st.st_size; /* truncated */
343 buffer_init(&buffer);
344 cp = buffer_append_space(&buffer, len);
346 if (read(fd, cp, (size_t) len) != (size_t) len) {
347 debug("Read from key file %.200s failed: %.100s", filename,
349 buffer_free(&buffer);
354 /* Check that it is at least big enough to contain the ID string. */
355 if (len < sizeof(authfile_id_string)) {
356 debug3("Not a RSA1 key file %.200s.", filename);
357 buffer_free(&buffer);
362 * Make sure it begins with the id string. Consume the id string
365 for (i = 0; i < sizeof(authfile_id_string); i++)
366 if (buffer_get_char(&buffer) != authfile_id_string[i]) {
367 debug3("Not a RSA1 key file %.200s.", filename);
368 buffer_free(&buffer);
373 /* Read cipher type. */
374 cipher_type = buffer_get_char(&buffer);
375 (void) buffer_get_int(&buffer); /* Reserved data. */
377 /* Read the public key from the buffer. */
378 (void) buffer_get_int(&buffer);
379 prv = key_new_private(KEY_RSA1);
381 buffer_get_bignum(&buffer, prv->rsa->n);
382 buffer_get_bignum(&buffer, prv->rsa->e);
384 *commentp = buffer_get_string(&buffer, NULL);
386 xfree(buffer_get_string(&buffer, NULL));
388 /* Check that it is a supported cipher. */
389 cipher = cipher_by_number(cipher_type);
390 if (cipher == NULL) {
391 debug("Unsupported cipher %d used in key file %.200s.",
392 cipher_type, filename);
393 buffer_free(&buffer);
396 /* Initialize space for decrypted data. */
397 buffer_init(&decrypted);
398 cp = buffer_append_space(&decrypted, buffer_len(&buffer));
400 /* Rest of the buffer is encrypted. Decrypt it using the passphrase. */
401 cipher_set_key_string(&ciphercontext, cipher, passphrase,
403 cipher_crypt(&ciphercontext, cp,
404 buffer_ptr(&buffer), buffer_len(&buffer));
405 cipher_cleanup(&ciphercontext);
406 memset(&ciphercontext, 0, sizeof(ciphercontext));
407 buffer_free(&buffer);
409 check1 = buffer_get_char(&decrypted);
410 check2 = buffer_get_char(&decrypted);
411 if (check1 != buffer_get_char(&decrypted) ||
412 check2 != buffer_get_char(&decrypted)) {
413 if (strcmp(passphrase, "") != 0)
414 debug("Bad passphrase supplied for key file %.200s.",
416 /* Bad passphrase. */
417 buffer_free(&decrypted);
420 /* Read the rest of the private key. */
421 buffer_get_bignum(&decrypted, prv->rsa->d);
422 buffer_get_bignum(&decrypted, prv->rsa->iqmp); /* u */
423 /* in SSL and SSH v1 p and q are exchanged */
424 buffer_get_bignum(&decrypted, prv->rsa->q); /* p */
425 buffer_get_bignum(&decrypted, prv->rsa->p); /* q */
427 /* calculate p-1 and q-1 */
428 rsa_generate_additional_parameters(prv->rsa);
430 buffer_free(&decrypted);
432 /* enable blinding */
433 if (RSA_blinding_on(prv->rsa, NULL) != 1) {
434 error("key_load_private_rsa1: RSA_blinding_on failed");
449 key_load_private_pem(int fd, int type, const char *passphrase,
455 char *name = "<no key>";
457 fp = fdopen(fd, "r");
459 error("fdopen failed: %s", strerror(errno));
463 pk = PEM_read_PrivateKey(fp, NULL, NULL, (char *)passphrase);
465 debug("PEM_read_PrivateKey failed");
466 (void)ERR_get_error();
467 } else if (pk->type == EVP_PKEY_RSA &&
468 (type == KEY_UNSPEC||type==KEY_RSA)) {
469 prv = key_new(KEY_UNSPEC);
470 prv->rsa = EVP_PKEY_get1_RSA(pk);
472 name = "rsa w/o comment";
474 RSA_print_fp(stderr, prv->rsa, 8);
476 if (RSA_blinding_on(prv->rsa, NULL) != 1) {
477 error("key_load_private_pem: RSA_blinding_on failed");
481 } else if (pk->type == EVP_PKEY_DSA &&
482 (type == KEY_UNSPEC||type==KEY_DSA)) {
483 prv = key_new(KEY_UNSPEC);
484 prv->dsa = EVP_PKEY_get1_DSA(pk);
486 name = "dsa w/o comment";
488 DSA_print_fp(stderr, prv->dsa, 8);
491 error("PEM_read_PrivateKey: mismatch or "
492 "unknown EVP_PKEY save_type %d", pk->save_type);
497 if (prv != NULL && commentp)
498 *commentp = xstrdup(name);
499 debug("read PEM private key done: type %s",
500 prv ? key_type(prv) : "<unknown>");
505 key_perm_ok(int fd, const char *filename)
509 if (fstat(fd, &st) < 0)
512 * if a key owned by the user is accessed, then we check the
513 * permissions of the file. if the key owned by a different user,
514 * then we don't care.
517 if (check_ntsec(filename))
519 if ((st.st_uid == getuid()) && (st.st_mode & 077) != 0) {
520 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
521 error("@ WARNING: UNPROTECTED PRIVATE KEY FILE! @");
522 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
523 error("Permissions 0%3.3o for '%s' are too open.",
524 (u_int)st.st_mode & 0777, filename);
525 error("It is recommended that your private key files are NOT accessible by others.");
526 error("This private key will be ignored.");
533 key_load_private_type(int type, const char *filename, const char *passphrase,
538 fd = open(filename, O_RDONLY);
541 if (!key_perm_ok(fd, filename)) {
542 error("bad permissions: ignore key: %s", filename);
548 return key_load_private_rsa1(fd, filename, passphrase,
555 return key_load_private_pem(fd, type, passphrase, commentp);
566 key_load_private(const char *filename, const char *passphrase,
572 fd = open(filename, O_RDONLY);
575 if (!key_perm_ok(fd, filename)) {
576 error("bad permissions: ignore key: %s", filename);
580 pub = key_load_public_rsa1(fd, filename, commentp);
581 lseek(fd, (off_t) 0, SEEK_SET); /* rewind */
584 prv = key_load_private_pem(fd, KEY_UNSPEC, passphrase, NULL);
585 /* use the filename as a comment for PEM */
587 *commentp = xstrdup(filename);
589 /* it's a SSH v1 key if the public key part is readable */
592 prv = key_load_private_rsa1(fd, filename, passphrase, NULL);
598 key_try_load_public(Key *k, const char *filename, char **commentp)
604 f = fopen(filename, "r");
606 while (fgets(line, sizeof(line), f)) {
607 line[sizeof(line)-1] = '\0';
615 /* Skip leading whitespace. */
616 for (; *cp && (*cp == ' ' || *cp == '\t'); cp++)
619 if (key_read(k, &cp) == 1) {
621 *commentp=xstrdup(filename);
632 /* load public key from ssh v1 private or any pubkey file */
634 key_load_public(const char *filename, char **commentp)
637 char file[MAXPATHLEN];
639 /* try rsa1 private key */
640 pub = key_load_public_type(KEY_RSA1, filename, commentp);
644 /* try rsa1 public key */
645 pub = key_new(KEY_RSA1);
646 if (key_try_load_public(pub, filename, commentp) == 1)
650 /* try ssh2 public key */
651 pub = key_new(KEY_UNSPEC);
652 if (key_try_load_public(pub, filename, commentp) == 1)
654 if ((strlcpy(file, filename, sizeof file) < sizeof(file)) &&
655 (strlcat(file, ".pub", sizeof file) < sizeof(file)) &&
656 (key_try_load_public(pub, file, commentp) == 1))