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 1.61 2005/06/17 02:44:32 djm Exp $");
41 #include <openssl/err.h>
42 #include <openssl/evp.h>
43 #include <openssl/pem.h>
57 /* Version identification string for SSH v1 identity files. */
58 static const char authfile_id_string[] =
59 "SSH PRIVATE KEY FILE FORMAT 1.1\n";
62 * Saves the authentication (private) key in a file, encrypting it with
63 * passphrase. The identification of the file (lowest 64 bits of n) will
64 * precede the key to provide identification of the key without needing a
69 key_save_private_rsa1(Key *key, const char *filename, const char *passphrase,
72 Buffer buffer, encrypted;
74 int fd, i, cipher_num;
75 CipherContext ciphercontext;
80 * If the passphrase is empty, use SSH_CIPHER_NONE to ease converting
81 * to another cipher; otherwise use SSH_AUTHFILE_CIPHER.
83 cipher_num = (strcmp(passphrase, "") == 0) ?
84 SSH_CIPHER_NONE : SSH_AUTHFILE_CIPHER;
85 if ((cipher = cipher_by_number(cipher_num)) == NULL)
86 fatal("save_private_key_rsa: bad cipher");
88 /* This buffer is used to built the secret part of the private key. */
91 /* Put checkbytes for checking passphrase validity. */
94 buf[1] = (rnd >> 8) & 0xff;
97 buffer_append(&buffer, buf, 4);
100 * Store the private key (n and e will not be stored because they
101 * will be stored in plain text, and storing them also in encrypted
102 * format would just give known plaintext).
104 buffer_put_bignum(&buffer, key->rsa->d);
105 buffer_put_bignum(&buffer, key->rsa->iqmp);
106 buffer_put_bignum(&buffer, key->rsa->q); /* reverse from SSL p */
107 buffer_put_bignum(&buffer, key->rsa->p); /* reverse from SSL q */
109 /* Pad the part to be encrypted until its size is a multiple of 8. */
110 while (buffer_len(&buffer) % 8 != 0)
111 buffer_put_char(&buffer, 0);
113 /* This buffer will be used to contain the data in the file. */
114 buffer_init(&encrypted);
116 /* First store keyfile id string. */
117 for (i = 0; authfile_id_string[i]; i++)
118 buffer_put_char(&encrypted, authfile_id_string[i]);
119 buffer_put_char(&encrypted, 0);
121 /* Store cipher type. */
122 buffer_put_char(&encrypted, cipher_num);
123 buffer_put_int(&encrypted, 0); /* For future extension */
125 /* Store public key. This will be in plain text. */
126 buffer_put_int(&encrypted, BN_num_bits(key->rsa->n));
127 buffer_put_bignum(&encrypted, key->rsa->n);
128 buffer_put_bignum(&encrypted, key->rsa->e);
129 buffer_put_cstring(&encrypted, comment);
131 /* Allocate space for the private part of the key in the buffer. */
132 cp = buffer_append_space(&encrypted, buffer_len(&buffer));
134 cipher_set_key_string(&ciphercontext, cipher, passphrase,
136 cipher_crypt(&ciphercontext, cp,
137 buffer_ptr(&buffer), buffer_len(&buffer));
138 cipher_cleanup(&ciphercontext);
139 memset(&ciphercontext, 0, sizeof(ciphercontext));
141 /* Destroy temporary data. */
142 memset(buf, 0, sizeof(buf));
143 buffer_free(&buffer);
145 fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0600);
147 error("open %s failed: %s.", filename, strerror(errno));
148 buffer_free(&encrypted);
151 if (atomicio(vwrite, fd, buffer_ptr(&encrypted),
152 buffer_len(&encrypted)) != buffer_len(&encrypted)) {
153 error("write to key file %s failed: %s", filename,
155 buffer_free(&encrypted);
161 buffer_free(&encrypted);
165 /* save SSH v2 key in OpenSSL PEM format */
167 key_save_private_pem(Key *key, const char *filename, const char *_passphrase,
173 int len = strlen(_passphrase);
174 u_char *passphrase = (len > 0) ? (u_char *)_passphrase : NULL;
175 const EVP_CIPHER *cipher = (len > 0) ? EVP_des_ede3_cbc() : NULL;
177 if (len > 0 && len <= 4) {
178 error("passphrase too short: have %d bytes, need > 4", len);
181 fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0600);
183 error("open %s failed: %s.", filename, strerror(errno));
186 fp = fdopen(fd, "w");
188 error("fdopen %s failed: %s.", filename, strerror(errno));
194 success = PEM_write_DSAPrivateKey(fp, key->dsa,
195 cipher, passphrase, len, NULL, NULL);
198 success = PEM_write_RSAPrivateKey(fp, key->rsa,
199 cipher, passphrase, len, NULL, NULL);
207 key_save_private(Key *key, const char *filename, const char *passphrase,
212 return key_save_private_rsa1(key, filename, passphrase,
217 return key_save_private_pem(key, filename, passphrase,
223 error("key_save_private: cannot save key type %d", key->type);
228 * Loads the public part of the ssh v1 key file. Returns NULL if an error was
229 * encountered (the file does not exist or is not readable), and the key
234 key_load_public_rsa1(int fd, const char *filename, char **commentp)
243 if (fstat(fd, &st) < 0) {
244 error("fstat for key file %.200s failed: %.100s",
245 filename, strerror(errno));
248 if (st.st_size > 1*1024*1024) {
249 error("key file %.200s too large", filename);
252 len = (size_t)st.st_size; /* truncated */
254 buffer_init(&buffer);
255 cp = buffer_append_space(&buffer, len);
257 if (atomicio(read, fd, cp, len) != len) {
258 debug("Read from key file %.200s failed: %.100s", filename,
260 buffer_free(&buffer);
264 /* Check that it is at least big enough to contain the ID string. */
265 if (len < sizeof(authfile_id_string)) {
266 debug3("Not a RSA1 key file %.200s.", filename);
267 buffer_free(&buffer);
271 * Make sure it begins with the id string. Consume the id string
274 for (i = 0; i < sizeof(authfile_id_string); i++)
275 if (buffer_get_char(&buffer) != authfile_id_string[i]) {
276 debug3("Not a RSA1 key file %.200s.", filename);
277 buffer_free(&buffer);
280 /* Skip cipher type and reserved data. */
281 (void) buffer_get_char(&buffer); /* cipher type */
282 (void) buffer_get_int(&buffer); /* reserved */
284 /* Read the public key from the buffer. */
285 (void) buffer_get_int(&buffer);
286 pub = key_new(KEY_RSA1);
287 buffer_get_bignum(&buffer, pub->rsa->n);
288 buffer_get_bignum(&buffer, pub->rsa->e);
290 *commentp = buffer_get_string(&buffer, NULL);
291 /* The encrypted private part is not parsed by this function. */
293 buffer_free(&buffer);
297 /* load public key from private-key file, works only for SSH v1 */
299 key_load_public_type(int type, const char *filename, char **commentp)
304 if (type == KEY_RSA1) {
305 fd = open(filename, O_RDONLY);
308 pub = key_load_public_rsa1(fd, filename, commentp);
316 * Loads the private key from the file. Returns 0 if an error is encountered
317 * (file does not exist or is not readable, or passphrase is bad). This
318 * initializes the private key.
319 * Assumes we are called under uid of the owner of the file.
323 key_load_private_rsa1(int fd, const char *filename, const char *passphrase,
327 int check1, check2, cipher_type;
329 Buffer buffer, decrypted;
331 CipherContext ciphercontext;
336 if (fstat(fd, &st) < 0) {
337 error("fstat for key file %.200s failed: %.100s",
338 filename, strerror(errno));
342 if (st.st_size > 1*1024*1024) {
343 error("key file %.200s too large", filename);
347 len = (size_t)st.st_size; /* truncated */
349 buffer_init(&buffer);
350 cp = buffer_append_space(&buffer, len);
352 if (atomicio(read, fd, cp, len) != len) {
353 debug("Read from key file %.200s failed: %.100s", filename,
355 buffer_free(&buffer);
360 /* Check that it is at least big enough to contain the ID string. */
361 if (len < sizeof(authfile_id_string)) {
362 debug3("Not a RSA1 key file %.200s.", filename);
363 buffer_free(&buffer);
368 * Make sure it begins with the id string. Consume the id string
371 for (i = 0; i < sizeof(authfile_id_string); i++)
372 if (buffer_get_char(&buffer) != authfile_id_string[i]) {
373 debug3("Not a RSA1 key file %.200s.", filename);
374 buffer_free(&buffer);
379 /* Read cipher type. */
380 cipher_type = buffer_get_char(&buffer);
381 (void) buffer_get_int(&buffer); /* Reserved data. */
383 /* Read the public key from the buffer. */
384 (void) buffer_get_int(&buffer);
385 prv = key_new_private(KEY_RSA1);
387 buffer_get_bignum(&buffer, prv->rsa->n);
388 buffer_get_bignum(&buffer, prv->rsa->e);
390 *commentp = buffer_get_string(&buffer, NULL);
392 xfree(buffer_get_string(&buffer, NULL));
394 /* Check that it is a supported cipher. */
395 cipher = cipher_by_number(cipher_type);
396 if (cipher == NULL) {
397 debug("Unsupported cipher %d used in key file %.200s.",
398 cipher_type, filename);
399 buffer_free(&buffer);
402 /* Initialize space for decrypted data. */
403 buffer_init(&decrypted);
404 cp = buffer_append_space(&decrypted, buffer_len(&buffer));
406 /* Rest of the buffer is encrypted. Decrypt it using the passphrase. */
407 cipher_set_key_string(&ciphercontext, cipher, passphrase,
409 cipher_crypt(&ciphercontext, cp,
410 buffer_ptr(&buffer), buffer_len(&buffer));
411 cipher_cleanup(&ciphercontext);
412 memset(&ciphercontext, 0, sizeof(ciphercontext));
413 buffer_free(&buffer);
415 check1 = buffer_get_char(&decrypted);
416 check2 = buffer_get_char(&decrypted);
417 if (check1 != buffer_get_char(&decrypted) ||
418 check2 != buffer_get_char(&decrypted)) {
419 if (strcmp(passphrase, "") != 0)
420 debug("Bad passphrase supplied for key file %.200s.",
422 /* Bad passphrase. */
423 buffer_free(&decrypted);
426 /* Read the rest of the private key. */
427 buffer_get_bignum(&decrypted, prv->rsa->d);
428 buffer_get_bignum(&decrypted, prv->rsa->iqmp); /* u */
429 /* in SSL and SSH v1 p and q are exchanged */
430 buffer_get_bignum(&decrypted, prv->rsa->q); /* p */
431 buffer_get_bignum(&decrypted, prv->rsa->p); /* q */
433 /* calculate p-1 and q-1 */
434 rsa_generate_additional_parameters(prv->rsa);
436 buffer_free(&decrypted);
438 /* enable blinding */
439 if (RSA_blinding_on(prv->rsa, NULL) != 1) {
440 error("key_load_private_rsa1: RSA_blinding_on failed");
455 key_load_private_pem(int fd, int type, const char *passphrase,
461 char *name = "<no key>";
463 fp = fdopen(fd, "r");
465 error("fdopen failed: %s", strerror(errno));
469 pk = PEM_read_PrivateKey(fp, NULL, NULL, (char *)passphrase);
471 debug("PEM_read_PrivateKey failed");
472 (void)ERR_get_error();
473 } else if (pk->type == EVP_PKEY_RSA &&
474 (type == KEY_UNSPEC||type==KEY_RSA)) {
475 prv = key_new(KEY_UNSPEC);
476 prv->rsa = EVP_PKEY_get1_RSA(pk);
478 name = "rsa w/o comment";
480 RSA_print_fp(stderr, prv->rsa, 8);
482 if (RSA_blinding_on(prv->rsa, NULL) != 1) {
483 error("key_load_private_pem: RSA_blinding_on failed");
487 } else if (pk->type == EVP_PKEY_DSA &&
488 (type == KEY_UNSPEC||type==KEY_DSA)) {
489 prv = key_new(KEY_UNSPEC);
490 prv->dsa = EVP_PKEY_get1_DSA(pk);
492 name = "dsa w/o comment";
494 DSA_print_fp(stderr, prv->dsa, 8);
497 error("PEM_read_PrivateKey: mismatch or "
498 "unknown EVP_PKEY save_type %d", pk->save_type);
503 if (prv != NULL && commentp)
504 *commentp = xstrdup(name);
505 debug("read PEM private key done: type %s",
506 prv ? key_type(prv) : "<unknown>");
511 key_perm_ok(int fd, const char *filename)
515 if (fstat(fd, &st) < 0)
518 * if a key owned by the user is accessed, then we check the
519 * permissions of the file. if the key owned by a different user,
520 * then we don't care.
523 if (check_ntsec(filename))
525 if ((st.st_uid == getuid()) && (st.st_mode & 077) != 0) {
526 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
527 error("@ WARNING: UNPROTECTED PRIVATE KEY FILE! @");
528 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
529 error("Permissions 0%3.3o for '%s' are too open.",
530 (u_int)st.st_mode & 0777, filename);
531 error("It is recommended that your private key files are NOT accessible by others.");
532 error("This private key will be ignored.");
539 key_load_private_type(int type, const char *filename, const char *passphrase,
544 fd = open(filename, O_RDONLY);
547 if (!key_perm_ok(fd, filename)) {
548 error("bad permissions: ignore key: %s", filename);
554 return key_load_private_rsa1(fd, filename, passphrase,
561 return key_load_private_pem(fd, type, passphrase, commentp);
572 key_load_private(const char *filename, const char *passphrase,
578 fd = open(filename, O_RDONLY);
581 if (!key_perm_ok(fd, filename)) {
582 error("bad permissions: ignore key: %s", filename);
586 pub = key_load_public_rsa1(fd, filename, commentp);
587 lseek(fd, (off_t) 0, SEEK_SET); /* rewind */
590 prv = key_load_private_pem(fd, KEY_UNSPEC, passphrase, NULL);
591 /* use the filename as a comment for PEM */
593 *commentp = xstrdup(filename);
595 /* it's a SSH v1 key if the public key part is readable */
598 prv = key_load_private_rsa1(fd, filename, passphrase, NULL);
604 key_try_load_public(Key *k, const char *filename, char **commentp)
607 char line[SSH_MAX_PUBKEY_BYTES];
611 f = fopen(filename, "r");
613 while (read_keyfile_line(f, filename, line, sizeof(line),
622 /* Skip leading whitespace. */
623 for (; *cp && (*cp == ' ' || *cp == '\t'); cp++)
626 if (key_read(k, &cp) == 1) {
628 *commentp=xstrdup(filename);
639 /* load public key from ssh v1 private or any pubkey file */
641 key_load_public(const char *filename, char **commentp)
644 char file[MAXPATHLEN];
646 /* try rsa1 private key */
647 pub = key_load_public_type(KEY_RSA1, filename, commentp);
651 /* try rsa1 public key */
652 pub = key_new(KEY_RSA1);
653 if (key_try_load_public(pub, filename, commentp) == 1)
657 /* try ssh2 public key */
658 pub = key_new(KEY_UNSPEC);
659 if (key_try_load_public(pub, filename, commentp) == 1)
661 if ((strlcpy(file, filename, sizeof file) < sizeof(file)) &&
662 (strlcat(file, ".pub", sizeof file) < sizeof(file)) &&
663 (key_try_load_public(pub, file, commentp) == 1))