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 1.55 2003/09/18 07:56:05 markus 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] = (rand >> 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));
248 buffer_init(&buffer);
249 cp = buffer_append_space(&buffer, len);
251 if (read(fd, cp, (size_t) len) != (size_t) len) {
252 debug("Read from key file %.200s failed: %.100s", filename,
254 buffer_free(&buffer);
258 /* Check that it is at least big enough to contain the ID string. */
259 if (len < sizeof(authfile_id_string)) {
260 debug3("Not a RSA1 key file %.200s.", filename);
261 buffer_free(&buffer);
265 * Make sure it begins with the id string. Consume the id string
268 for (i = 0; i < sizeof(authfile_id_string); i++)
269 if (buffer_get_char(&buffer) != authfile_id_string[i]) {
270 debug3("Not a RSA1 key file %.200s.", filename);
271 buffer_free(&buffer);
274 /* Skip cipher type and reserved data. */
275 (void) buffer_get_char(&buffer); /* cipher type */
276 (void) buffer_get_int(&buffer); /* reserved */
278 /* Read the public key from the buffer. */
279 (void) buffer_get_int(&buffer);
280 pub = key_new(KEY_RSA1);
281 buffer_get_bignum(&buffer, pub->rsa->n);
282 buffer_get_bignum(&buffer, pub->rsa->e);
284 *commentp = buffer_get_string(&buffer, NULL);
285 /* The encrypted private part is not parsed by this function. */
287 buffer_free(&buffer);
291 /* load public key from private-key file, works only for SSH v1 */
293 key_load_public_type(int type, const char *filename, char **commentp)
298 if (type == KEY_RSA1) {
299 fd = open(filename, O_RDONLY);
302 pub = key_load_public_rsa1(fd, filename, commentp);
310 * Loads the private key from the file. Returns 0 if an error is encountered
311 * (file does not exist or is not readable, or passphrase is bad). This
312 * initializes the private key.
313 * Assumes we are called under uid of the owner of the file.
317 key_load_private_rsa1(int fd, const char *filename, const char *passphrase,
320 int i, check1, check2, cipher_type;
322 Buffer buffer, decrypted;
324 CipherContext ciphercontext;
329 if (fstat(fd, &st) < 0) {
330 error("fstat for key file %.200s failed: %.100s",
331 filename, strerror(errno));
337 buffer_init(&buffer);
338 cp = buffer_append_space(&buffer, len);
340 if (read(fd, cp, (size_t) len) != (size_t) len) {
341 debug("Read from key file %.200s failed: %.100s", filename,
343 buffer_free(&buffer);
348 /* Check that it is at least big enough to contain the ID string. */
349 if (len < sizeof(authfile_id_string)) {
350 debug3("Not a RSA1 key file %.200s.", filename);
351 buffer_free(&buffer);
356 * Make sure it begins with the id string. Consume the id string
359 for (i = 0; i < sizeof(authfile_id_string); i++)
360 if (buffer_get_char(&buffer) != authfile_id_string[i]) {
361 debug3("Not a RSA1 key file %.200s.", filename);
362 buffer_free(&buffer);
367 /* Read cipher type. */
368 cipher_type = buffer_get_char(&buffer);
369 (void) buffer_get_int(&buffer); /* Reserved data. */
371 /* Read the public key from the buffer. */
372 (void) buffer_get_int(&buffer);
373 prv = key_new_private(KEY_RSA1);
375 buffer_get_bignum(&buffer, prv->rsa->n);
376 buffer_get_bignum(&buffer, prv->rsa->e);
378 *commentp = buffer_get_string(&buffer, NULL);
380 xfree(buffer_get_string(&buffer, NULL));
382 /* Check that it is a supported cipher. */
383 cipher = cipher_by_number(cipher_type);
384 if (cipher == NULL) {
385 debug("Unsupported cipher %d used in key file %.200s.",
386 cipher_type, filename);
387 buffer_free(&buffer);
390 /* Initialize space for decrypted data. */
391 buffer_init(&decrypted);
392 cp = buffer_append_space(&decrypted, buffer_len(&buffer));
394 /* Rest of the buffer is encrypted. Decrypt it using the passphrase. */
395 cipher_set_key_string(&ciphercontext, cipher, passphrase,
397 cipher_crypt(&ciphercontext, cp,
398 buffer_ptr(&buffer), buffer_len(&buffer));
399 cipher_cleanup(&ciphercontext);
400 memset(&ciphercontext, 0, sizeof(ciphercontext));
401 buffer_free(&buffer);
403 check1 = buffer_get_char(&decrypted);
404 check2 = buffer_get_char(&decrypted);
405 if (check1 != buffer_get_char(&decrypted) ||
406 check2 != buffer_get_char(&decrypted)) {
407 if (strcmp(passphrase, "") != 0)
408 debug("Bad passphrase supplied for key file %.200s.",
410 /* Bad passphrase. */
411 buffer_free(&decrypted);
414 /* Read the rest of the private key. */
415 buffer_get_bignum(&decrypted, prv->rsa->d);
416 buffer_get_bignum(&decrypted, prv->rsa->iqmp); /* u */
417 /* in SSL and SSH v1 p and q are exchanged */
418 buffer_get_bignum(&decrypted, prv->rsa->q); /* p */
419 buffer_get_bignum(&decrypted, prv->rsa->p); /* q */
421 /* calculate p-1 and q-1 */
422 rsa_generate_additional_parameters(prv->rsa);
424 buffer_free(&decrypted);
426 /* enable blinding */
427 if (RSA_blinding_on(prv->rsa, NULL) != 1) {
428 error("key_load_private_rsa1: RSA_blinding_on failed");
443 key_load_private_pem(int fd, int type, const char *passphrase,
449 char *name = "<no key>";
451 fp = fdopen(fd, "r");
453 error("fdopen failed: %s", strerror(errno));
457 pk = PEM_read_PrivateKey(fp, NULL, NULL, (char *)passphrase);
459 debug("PEM_read_PrivateKey failed");
460 (void)ERR_get_error();
461 } else if (pk->type == EVP_PKEY_RSA &&
462 (type == KEY_UNSPEC||type==KEY_RSA)) {
463 prv = key_new(KEY_UNSPEC);
464 prv->rsa = EVP_PKEY_get1_RSA(pk);
466 name = "rsa w/o comment";
468 RSA_print_fp(stderr, prv->rsa, 8);
470 if (RSA_blinding_on(prv->rsa, NULL) != 1) {
471 error("key_load_private_pem: RSA_blinding_on failed");
475 } else if (pk->type == EVP_PKEY_DSA &&
476 (type == KEY_UNSPEC||type==KEY_DSA)) {
477 prv = key_new(KEY_UNSPEC);
478 prv->dsa = EVP_PKEY_get1_DSA(pk);
480 name = "dsa w/o comment";
482 DSA_print_fp(stderr, prv->dsa, 8);
485 error("PEM_read_PrivateKey: mismatch or "
486 "unknown EVP_PKEY save_type %d", pk->save_type);
491 if (prv != NULL && commentp)
492 *commentp = xstrdup(name);
493 debug("read PEM private key done: type %s",
494 prv ? key_type(prv) : "<unknown>");
499 key_perm_ok(int fd, const char *filename)
503 if (fstat(fd, &st) < 0)
506 * if a key owned by the user is accessed, then we check the
507 * permissions of the file. if the key owned by a different user,
508 * then we don't care.
511 if (check_ntsec(filename))
513 if ((st.st_uid == getuid()) && (st.st_mode & 077) != 0) {
514 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
515 error("@ WARNING: UNPROTECTED PRIVATE KEY FILE! @");
516 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
517 error("Permissions 0%3.3o for '%s' are too open.",
518 (u_int)st.st_mode & 0777, filename);
519 error("It is recommended that your private key files are NOT accessible by others.");
520 error("This private key will be ignored.");
527 key_load_private_type(int type, const char *filename, const char *passphrase,
532 fd = open(filename, O_RDONLY);
535 if (!key_perm_ok(fd, filename)) {
536 error("bad permissions: ignore key: %s", filename);
542 return key_load_private_rsa1(fd, filename, passphrase,
549 return key_load_private_pem(fd, type, passphrase, commentp);
560 key_load_private(const char *filename, const char *passphrase,
566 fd = open(filename, O_RDONLY);
569 if (!key_perm_ok(fd, filename)) {
570 error("bad permissions: ignore key: %s", filename);
574 pub = key_load_public_rsa1(fd, filename, commentp);
575 lseek(fd, (off_t) 0, SEEK_SET); /* rewind */
578 prv = key_load_private_pem(fd, KEY_UNSPEC, passphrase, NULL);
579 /* use the filename as a comment for PEM */
581 *commentp = xstrdup(filename);
583 /* it's a SSH v1 key if the public key part is readable */
586 prv = key_load_private_rsa1(fd, filename, passphrase, NULL);
592 key_try_load_public(Key *k, const char *filename, char **commentp)
598 f = fopen(filename, "r");
600 while (fgets(line, sizeof(line), f)) {
601 line[sizeof(line)-1] = '\0';
609 /* Skip leading whitespace. */
610 for (; *cp && (*cp == ' ' || *cp == '\t'); cp++)
613 if (key_read(k, &cp) == 1) {
615 *commentp=xstrdup(filename);
626 /* load public key from ssh v1 private or any pubkey file */
628 key_load_public(const char *filename, char **commentp)
631 char file[MAXPATHLEN];
633 /* try rsa1 private key */
634 pub = key_load_public_type(KEY_RSA1, filename, commentp);
638 /* try rsa1 public key */
639 pub = key_new(KEY_RSA1);
640 if (key_try_load_public(pub, filename, commentp) == 1)
644 /* try ssh2 public key */
645 pub = key_new(KEY_UNSPEC);
646 if (key_try_load_public(pub, filename, commentp) == 1)
648 if ((strlcpy(file, filename, sizeof file) < sizeof(file)) &&
649 (strlcat(file, ".pub", sizeof file) < sizeof(file)) &&
650 (key_try_load_public(pub, file, commentp) == 1))