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 1.54 2003/05/24 09:30:39 djm 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));
148 if (write(fd, buffer_ptr(&encrypted), buffer_len(&encrypted)) !=
149 buffer_len(&encrypted)) {
150 error("write to key file %s failed: %s", filename,
152 buffer_free(&encrypted);
158 buffer_free(&encrypted);
162 /* save SSH v2 key in OpenSSL PEM format */
164 key_save_private_pem(Key *key, const char *filename, const char *_passphrase,
170 int len = strlen(_passphrase);
171 u_char *passphrase = (len > 0) ? (u_char *)_passphrase : NULL;
172 const EVP_CIPHER *cipher = (len > 0) ? EVP_des_ede3_cbc() : NULL;
174 if (len > 0 && len <= 4) {
175 error("passphrase too short: have %d bytes, need > 4", len);
178 fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0600);
180 error("open %s failed: %s.", filename, strerror(errno));
183 fp = fdopen(fd, "w");
185 error("fdopen %s failed: %s.", filename, strerror(errno));
191 success = PEM_write_DSAPrivateKey(fp, key->dsa,
192 cipher, passphrase, len, NULL, NULL);
195 success = PEM_write_RSAPrivateKey(fp, key->rsa,
196 cipher, passphrase, len, NULL, NULL);
204 key_save_private(Key *key, const char *filename, const char *passphrase,
209 return key_save_private_rsa1(key, filename, passphrase,
214 return key_save_private_pem(key, filename, passphrase,
220 error("key_save_private: cannot save key type %d", key->type);
225 * Loads the public part of the ssh v1 key file. Returns NULL if an error was
226 * encountered (the file does not exist or is not readable), and the key
231 key_load_public_rsa1(int fd, const char *filename, char **commentp)
240 if (fstat(fd, &st) < 0) {
241 error("fstat for key file %.200s failed: %.100s",
242 filename, strerror(errno));
247 buffer_init(&buffer);
248 cp = buffer_append_space(&buffer, len);
250 if (read(fd, cp, (size_t) len) != (size_t) len) {
251 debug("Read from key file %.200s failed: %.100s", filename,
253 buffer_free(&buffer);
257 /* Check that it is at least big enough to contain the ID string. */
258 if (len < sizeof(authfile_id_string)) {
259 debug3("Not a RSA1 key file %.200s.", filename);
260 buffer_free(&buffer);
264 * Make sure it begins with the id string. Consume the id string
267 for (i = 0; i < sizeof(authfile_id_string); i++)
268 if (buffer_get_char(&buffer) != authfile_id_string[i]) {
269 debug3("Not a RSA1 key file %.200s.", filename);
270 buffer_free(&buffer);
273 /* Skip cipher type and reserved data. */
274 (void) buffer_get_char(&buffer); /* cipher type */
275 (void) buffer_get_int(&buffer); /* reserved */
277 /* Read the public key from the buffer. */
278 (void) buffer_get_int(&buffer);
279 pub = key_new(KEY_RSA1);
280 buffer_get_bignum(&buffer, pub->rsa->n);
281 buffer_get_bignum(&buffer, pub->rsa->e);
283 *commentp = buffer_get_string(&buffer, NULL);
284 /* The encrypted private part is not parsed by this function. */
286 buffer_free(&buffer);
290 /* load public key from private-key file, works only for SSH v1 */
292 key_load_public_type(int type, const char *filename, char **commentp)
297 if (type == KEY_RSA1) {
298 fd = open(filename, O_RDONLY);
301 pub = key_load_public_rsa1(fd, filename, commentp);
309 * Loads the private key from the file. Returns 0 if an error is encountered
310 * (file does not exist or is not readable, or passphrase is bad). This
311 * initializes the private key.
312 * Assumes we are called under uid of the owner of the file.
316 key_load_private_rsa1(int fd, const char *filename, const char *passphrase,
319 int i, check1, check2, cipher_type;
321 Buffer buffer, decrypted;
323 CipherContext ciphercontext;
328 if (fstat(fd, &st) < 0) {
329 error("fstat for key file %.200s failed: %.100s",
330 filename, strerror(errno));
336 buffer_init(&buffer);
337 cp = buffer_append_space(&buffer, len);
339 if (read(fd, cp, (size_t) len) != (size_t) len) {
340 debug("Read from key file %.200s failed: %.100s", filename,
342 buffer_free(&buffer);
347 /* Check that it is at least big enough to contain the ID string. */
348 if (len < sizeof(authfile_id_string)) {
349 debug3("Not a RSA1 key file %.200s.", filename);
350 buffer_free(&buffer);
355 * Make sure it begins with the id string. Consume the id string
358 for (i = 0; i < sizeof(authfile_id_string); i++)
359 if (buffer_get_char(&buffer) != authfile_id_string[i]) {
360 debug3("Not a RSA1 key file %.200s.", filename);
361 buffer_free(&buffer);
366 /* Read cipher type. */
367 cipher_type = buffer_get_char(&buffer);
368 (void) buffer_get_int(&buffer); /* Reserved data. */
370 /* Read the public key from the buffer. */
371 (void) buffer_get_int(&buffer);
372 prv = key_new_private(KEY_RSA1);
374 buffer_get_bignum(&buffer, prv->rsa->n);
375 buffer_get_bignum(&buffer, prv->rsa->e);
377 *commentp = buffer_get_string(&buffer, NULL);
379 xfree(buffer_get_string(&buffer, NULL));
381 /* Check that it is a supported cipher. */
382 cipher = cipher_by_number(cipher_type);
383 if (cipher == NULL) {
384 debug("Unsupported cipher %d used in key file %.200s.",
385 cipher_type, filename);
386 buffer_free(&buffer);
389 /* Initialize space for decrypted data. */
390 buffer_init(&decrypted);
391 cp = buffer_append_space(&decrypted, buffer_len(&buffer));
393 /* Rest of the buffer is encrypted. Decrypt it using the passphrase. */
394 cipher_set_key_string(&ciphercontext, cipher, passphrase,
396 cipher_crypt(&ciphercontext, cp,
397 buffer_ptr(&buffer), buffer_len(&buffer));
398 cipher_cleanup(&ciphercontext);
399 memset(&ciphercontext, 0, sizeof(ciphercontext));
400 buffer_free(&buffer);
402 check1 = buffer_get_char(&decrypted);
403 check2 = buffer_get_char(&decrypted);
404 if (check1 != buffer_get_char(&decrypted) ||
405 check2 != buffer_get_char(&decrypted)) {
406 if (strcmp(passphrase, "") != 0)
407 debug("Bad passphrase supplied for key file %.200s.",
409 /* Bad passphrase. */
410 buffer_free(&decrypted);
413 /* Read the rest of the private key. */
414 buffer_get_bignum(&decrypted, prv->rsa->d);
415 buffer_get_bignum(&decrypted, prv->rsa->iqmp); /* u */
416 /* in SSL and SSH v1 p and q are exchanged */
417 buffer_get_bignum(&decrypted, prv->rsa->q); /* p */
418 buffer_get_bignum(&decrypted, prv->rsa->p); /* q */
420 /* calculate p-1 and q-1 */
421 rsa_generate_additional_parameters(prv->rsa);
423 buffer_free(&decrypted);
425 /* enable blinding */
426 if (RSA_blinding_on(prv->rsa, NULL) != 1) {
427 error("key_load_private_rsa1: RSA_blinding_on failed");
442 key_load_private_pem(int fd, int type, const char *passphrase,
448 char *name = "<no key>";
450 fp = fdopen(fd, "r");
452 error("fdopen failed: %s", strerror(errno));
456 pk = PEM_read_PrivateKey(fp, NULL, NULL, (char *)passphrase);
458 debug("PEM_read_PrivateKey failed");
459 (void)ERR_get_error();
460 } else if (pk->type == EVP_PKEY_RSA &&
461 (type == KEY_UNSPEC||type==KEY_RSA)) {
462 prv = key_new(KEY_UNSPEC);
463 prv->rsa = EVP_PKEY_get1_RSA(pk);
465 name = "rsa w/o comment";
467 RSA_print_fp(stderr, prv->rsa, 8);
469 if (RSA_blinding_on(prv->rsa, NULL) != 1) {
470 error("key_load_private_pem: RSA_blinding_on failed");
474 } else if (pk->type == EVP_PKEY_DSA &&
475 (type == KEY_UNSPEC||type==KEY_DSA)) {
476 prv = key_new(KEY_UNSPEC);
477 prv->dsa = EVP_PKEY_get1_DSA(pk);
479 name = "dsa w/o comment";
481 DSA_print_fp(stderr, prv->dsa, 8);
484 error("PEM_read_PrivateKey: mismatch or "
485 "unknown EVP_PKEY save_type %d", pk->save_type);
490 if (prv != NULL && commentp)
491 *commentp = xstrdup(name);
492 debug("read PEM private key done: type %s",
493 prv ? key_type(prv) : "<unknown>");
498 key_perm_ok(int fd, const char *filename)
502 if (fstat(fd, &st) < 0)
505 * if a key owned by the user is accessed, then we check the
506 * permissions of the file. if the key owned by a different user,
507 * then we don't care.
510 if (check_ntsec(filename))
512 if ((st.st_uid == getuid()) && (st.st_mode & 077) != 0) {
513 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
514 error("@ WARNING: UNPROTECTED PRIVATE KEY FILE! @");
515 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
516 error("Permissions 0%3.3o for '%s' are too open.",
517 (u_int)st.st_mode & 0777, filename);
518 error("It is recommended that your private key files are NOT accessible by others.");
519 error("This private key will be ignored.");
526 key_load_private_type(int type, const char *filename, const char *passphrase,
531 fd = open(filename, O_RDONLY);
534 if (!key_perm_ok(fd, filename)) {
535 error("bad permissions: ignore key: %s", filename);
541 return key_load_private_rsa1(fd, filename, passphrase,
548 return key_load_private_pem(fd, type, passphrase, commentp);
559 key_load_private(const char *filename, const char *passphrase,
565 fd = open(filename, O_RDONLY);
568 if (!key_perm_ok(fd, filename)) {
569 error("bad permissions: ignore key: %s", filename);
573 pub = key_load_public_rsa1(fd, filename, commentp);
574 lseek(fd, (off_t) 0, SEEK_SET); /* rewind */
577 prv = key_load_private_pem(fd, KEY_UNSPEC, passphrase, NULL);
578 /* use the filename as a comment for PEM */
580 *commentp = xstrdup(filename);
582 /* it's a SSH v1 key if the public key part is readable */
585 prv = key_load_private_rsa1(fd, filename, passphrase, NULL);
591 key_try_load_public(Key *k, const char *filename, char **commentp)
597 f = fopen(filename, "r");
599 while (fgets(line, sizeof(line), f)) {
600 line[sizeof(line)-1] = '\0';
608 /* Skip leading whitespace. */
609 for (; *cp && (*cp == ' ' || *cp == '\t'); cp++)
612 if (key_read(k, &cp) == 1) {
614 *commentp=xstrdup(filename);
625 /* load public key from ssh v1 private or any pubkey file */
627 key_load_public(const char *filename, char **commentp)
630 char file[MAXPATHLEN];
632 /* try rsa1 private key */
633 pub = key_load_public_type(KEY_RSA1, filename, commentp);
637 /* try rsa1 public key */
638 pub = key_new(KEY_RSA1);
639 if (key_try_load_public(pub, filename, commentp) == 1)
643 /* try ssh2 public key */
644 pub = key_new(KEY_UNSPEC);
645 if (key_try_load_public(pub, filename, commentp) == 1)
647 if ((strlcpy(file, filename, sizeof file) < sizeof(file)) &&
648 (strlcat(file, ".pub", sizeof file) < sizeof(file)) &&
649 (key_try_load_public(pub, file, commentp) == 1))