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 1.63 2006/03/13 10:26:52 dtucker Exp $");
41 #include <sys/types.h>
44 #include <openssl/err.h>
45 #include <openssl/evp.h>
46 #include <openssl/pem.h>
60 /* Version identification string for SSH v1 identity files. */
61 static const char authfile_id_string[] =
62 "SSH PRIVATE KEY FILE FORMAT 1.1\n";
65 * Saves the authentication (private) key in a file, encrypting it with
66 * passphrase. The identification of the file (lowest 64 bits of n) will
67 * precede the key to provide identification of the key without needing a
72 key_save_private_rsa1(Key *key, const char *filename, const char *passphrase,
75 Buffer buffer, encrypted;
77 int fd, i, cipher_num;
78 CipherContext ciphercontext;
83 * If the passphrase is empty, use SSH_CIPHER_NONE to ease converting
84 * to another cipher; otherwise use SSH_AUTHFILE_CIPHER.
86 cipher_num = (strcmp(passphrase, "") == 0) ?
87 SSH_CIPHER_NONE : SSH_AUTHFILE_CIPHER;
88 if ((cipher = cipher_by_number(cipher_num)) == NULL)
89 fatal("save_private_key_rsa: bad cipher");
91 /* This buffer is used to built the secret part of the private key. */
94 /* Put checkbytes for checking passphrase validity. */
97 buf[1] = (rnd >> 8) & 0xff;
100 buffer_append(&buffer, buf, 4);
103 * Store the private key (n and e will not be stored because they
104 * will be stored in plain text, and storing them also in encrypted
105 * format would just give known plaintext).
107 buffer_put_bignum(&buffer, key->rsa->d);
108 buffer_put_bignum(&buffer, key->rsa->iqmp);
109 buffer_put_bignum(&buffer, key->rsa->q); /* reverse from SSL p */
110 buffer_put_bignum(&buffer, key->rsa->p); /* reverse from SSL q */
112 /* Pad the part to be encrypted until its size is a multiple of 8. */
113 while (buffer_len(&buffer) % 8 != 0)
114 buffer_put_char(&buffer, 0);
116 /* This buffer will be used to contain the data in the file. */
117 buffer_init(&encrypted);
119 /* First store keyfile id string. */
120 for (i = 0; authfile_id_string[i]; i++)
121 buffer_put_char(&encrypted, authfile_id_string[i]);
122 buffer_put_char(&encrypted, 0);
124 /* Store cipher type. */
125 buffer_put_char(&encrypted, cipher_num);
126 buffer_put_int(&encrypted, 0); /* For future extension */
128 /* Store public key. This will be in plain text. */
129 buffer_put_int(&encrypted, BN_num_bits(key->rsa->n));
130 buffer_put_bignum(&encrypted, key->rsa->n);
131 buffer_put_bignum(&encrypted, key->rsa->e);
132 buffer_put_cstring(&encrypted, comment);
134 /* Allocate space for the private part of the key in the buffer. */
135 cp = buffer_append_space(&encrypted, buffer_len(&buffer));
137 cipher_set_key_string(&ciphercontext, cipher, passphrase,
139 cipher_crypt(&ciphercontext, cp,
140 buffer_ptr(&buffer), buffer_len(&buffer));
141 cipher_cleanup(&ciphercontext);
142 memset(&ciphercontext, 0, sizeof(ciphercontext));
144 /* Destroy temporary data. */
145 memset(buf, 0, sizeof(buf));
146 buffer_free(&buffer);
148 fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0600);
150 error("open %s failed: %s.", filename, strerror(errno));
151 buffer_free(&encrypted);
154 if (atomicio(vwrite, fd, buffer_ptr(&encrypted),
155 buffer_len(&encrypted)) != buffer_len(&encrypted)) {
156 error("write to key file %s failed: %s", filename,
158 buffer_free(&encrypted);
164 buffer_free(&encrypted);
168 /* save SSH v2 key in OpenSSL PEM format */
170 key_save_private_pem(Key *key, const char *filename, const char *_passphrase,
176 int len = strlen(_passphrase);
177 u_char *passphrase = (len > 0) ? (u_char *)_passphrase : NULL;
178 const EVP_CIPHER *cipher = (len > 0) ? EVP_des_ede3_cbc() : NULL;
180 if (len > 0 && len <= 4) {
181 error("passphrase too short: have %d bytes, need > 4", len);
184 fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0600);
186 error("open %s failed: %s.", filename, strerror(errno));
189 fp = fdopen(fd, "w");
191 error("fdopen %s failed: %s.", filename, strerror(errno));
197 success = PEM_write_DSAPrivateKey(fp, key->dsa,
198 cipher, passphrase, len, NULL, NULL);
201 success = PEM_write_RSAPrivateKey(fp, key->rsa,
202 cipher, passphrase, len, NULL, NULL);
210 key_save_private(Key *key, const char *filename, const char *passphrase,
215 return key_save_private_rsa1(key, filename, passphrase,
220 return key_save_private_pem(key, filename, passphrase,
226 error("key_save_private: cannot save key type %d", key->type);
231 * Loads the public part of the ssh v1 key file. Returns NULL if an error was
232 * encountered (the file does not exist or is not readable), and the key
237 key_load_public_rsa1(int fd, const char *filename, char **commentp)
246 if (fstat(fd, &st) < 0) {
247 error("fstat for key file %.200s failed: %.100s",
248 filename, strerror(errno));
251 if (st.st_size > 1*1024*1024) {
252 error("key file %.200s too large", filename);
255 len = (size_t)st.st_size; /* truncated */
257 buffer_init(&buffer);
258 cp = buffer_append_space(&buffer, len);
260 if (atomicio(read, fd, cp, len) != len) {
261 debug("Read from key file %.200s failed: %.100s", filename,
263 buffer_free(&buffer);
267 /* Check that it is at least big enough to contain the ID string. */
268 if (len < sizeof(authfile_id_string)) {
269 debug3("Not a RSA1 key file %.200s.", filename);
270 buffer_free(&buffer);
274 * Make sure it begins with the id string. Consume the id string
277 for (i = 0; i < sizeof(authfile_id_string); i++)
278 if (buffer_get_char(&buffer) != authfile_id_string[i]) {
279 debug3("Not a RSA1 key file %.200s.", filename);
280 buffer_free(&buffer);
283 /* Skip cipher type and reserved data. */
284 (void) buffer_get_char(&buffer); /* cipher type */
285 (void) buffer_get_int(&buffer); /* reserved */
287 /* Read the public key from the buffer. */
288 (void) buffer_get_int(&buffer);
289 pub = key_new(KEY_RSA1);
290 buffer_get_bignum(&buffer, pub->rsa->n);
291 buffer_get_bignum(&buffer, pub->rsa->e);
293 *commentp = buffer_get_string(&buffer, NULL);
294 /* The encrypted private part is not parsed by this function. */
296 buffer_free(&buffer);
300 /* load public key from private-key file, works only for SSH v1 */
302 key_load_public_type(int type, const char *filename, char **commentp)
307 if (type == KEY_RSA1) {
308 fd = open(filename, O_RDONLY);
311 pub = key_load_public_rsa1(fd, filename, commentp);
319 * Loads the private key from the file. Returns 0 if an error is encountered
320 * (file does not exist or is not readable, or passphrase is bad). This
321 * initializes the private key.
322 * Assumes we are called under uid of the owner of the file.
326 key_load_private_rsa1(int fd, const char *filename, const char *passphrase,
330 int check1, check2, cipher_type;
332 Buffer buffer, decrypted;
334 CipherContext ciphercontext;
339 if (fstat(fd, &st) < 0) {
340 error("fstat for key file %.200s failed: %.100s",
341 filename, strerror(errno));
345 if (st.st_size > 1*1024*1024) {
346 error("key file %.200s too large", filename);
350 len = (size_t)st.st_size; /* truncated */
352 buffer_init(&buffer);
353 cp = buffer_append_space(&buffer, len);
355 if (atomicio(read, fd, cp, len) != len) {
356 debug("Read from key file %.200s failed: %.100s", filename,
358 buffer_free(&buffer);
363 /* Check that it is at least big enough to contain the ID string. */
364 if (len < sizeof(authfile_id_string)) {
365 debug3("Not a RSA1 key file %.200s.", filename);
366 buffer_free(&buffer);
371 * Make sure it begins with the id string. Consume the id string
374 for (i = 0; i < sizeof(authfile_id_string); i++)
375 if (buffer_get_char(&buffer) != authfile_id_string[i]) {
376 debug3("Not a RSA1 key file %.200s.", filename);
377 buffer_free(&buffer);
382 /* Read cipher type. */
383 cipher_type = buffer_get_char(&buffer);
384 (void) buffer_get_int(&buffer); /* Reserved data. */
386 /* Read the public key from the buffer. */
387 (void) buffer_get_int(&buffer);
388 prv = key_new_private(KEY_RSA1);
390 buffer_get_bignum(&buffer, prv->rsa->n);
391 buffer_get_bignum(&buffer, prv->rsa->e);
393 *commentp = buffer_get_string(&buffer, NULL);
395 xfree(buffer_get_string(&buffer, NULL));
397 /* Check that it is a supported cipher. */
398 cipher = cipher_by_number(cipher_type);
399 if (cipher == NULL) {
400 debug("Unsupported cipher %d used in key file %.200s.",
401 cipher_type, filename);
402 buffer_free(&buffer);
405 /* Initialize space for decrypted data. */
406 buffer_init(&decrypted);
407 cp = buffer_append_space(&decrypted, buffer_len(&buffer));
409 /* Rest of the buffer is encrypted. Decrypt it using the passphrase. */
410 cipher_set_key_string(&ciphercontext, cipher, passphrase,
412 cipher_crypt(&ciphercontext, cp,
413 buffer_ptr(&buffer), buffer_len(&buffer));
414 cipher_cleanup(&ciphercontext);
415 memset(&ciphercontext, 0, sizeof(ciphercontext));
416 buffer_free(&buffer);
418 check1 = buffer_get_char(&decrypted);
419 check2 = buffer_get_char(&decrypted);
420 if (check1 != buffer_get_char(&decrypted) ||
421 check2 != buffer_get_char(&decrypted)) {
422 if (strcmp(passphrase, "") != 0)
423 debug("Bad passphrase supplied for key file %.200s.",
425 /* Bad passphrase. */
426 buffer_free(&decrypted);
429 /* Read the rest of the private key. */
430 buffer_get_bignum(&decrypted, prv->rsa->d);
431 buffer_get_bignum(&decrypted, prv->rsa->iqmp); /* u */
432 /* in SSL and SSH v1 p and q are exchanged */
433 buffer_get_bignum(&decrypted, prv->rsa->q); /* p */
434 buffer_get_bignum(&decrypted, prv->rsa->p); /* q */
436 /* calculate p-1 and q-1 */
437 rsa_generate_additional_parameters(prv->rsa);
439 buffer_free(&decrypted);
441 /* enable blinding */
442 if (RSA_blinding_on(prv->rsa, NULL) != 1) {
443 error("key_load_private_rsa1: RSA_blinding_on failed");
458 key_load_private_pem(int fd, int type, const char *passphrase,
464 char *name = "<no key>";
466 fp = fdopen(fd, "r");
468 error("fdopen failed: %s", strerror(errno));
472 pk = PEM_read_PrivateKey(fp, NULL, NULL, (char *)passphrase);
474 debug("PEM_read_PrivateKey failed");
475 (void)ERR_get_error();
476 } else if (pk->type == EVP_PKEY_RSA &&
477 (type == KEY_UNSPEC||type==KEY_RSA)) {
478 prv = key_new(KEY_UNSPEC);
479 prv->rsa = EVP_PKEY_get1_RSA(pk);
481 name = "rsa w/o comment";
483 RSA_print_fp(stderr, prv->rsa, 8);
485 if (RSA_blinding_on(prv->rsa, NULL) != 1) {
486 error("key_load_private_pem: RSA_blinding_on failed");
490 } else if (pk->type == EVP_PKEY_DSA &&
491 (type == KEY_UNSPEC||type==KEY_DSA)) {
492 prv = key_new(KEY_UNSPEC);
493 prv->dsa = EVP_PKEY_get1_DSA(pk);
495 name = "dsa w/o comment";
497 DSA_print_fp(stderr, prv->dsa, 8);
500 error("PEM_read_PrivateKey: mismatch or "
501 "unknown EVP_PKEY save_type %d", pk->save_type);
506 if (prv != NULL && commentp)
507 *commentp = xstrdup(name);
508 debug("read PEM private key done: type %s",
509 prv ? key_type(prv) : "<unknown>");
514 key_perm_ok(int fd, const char *filename)
518 if (fstat(fd, &st) < 0)
521 * if a key owned by the user is accessed, then we check the
522 * permissions of the file. if the key owned by a different user,
523 * then we don't care.
526 if (check_ntsec(filename))
528 if ((st.st_uid == getuid()) && (st.st_mode & 077) != 0) {
529 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
530 error("@ WARNING: UNPROTECTED PRIVATE KEY FILE! @");
531 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
532 error("Permissions 0%3.3o for '%s' are too open.",
533 (u_int)st.st_mode & 0777, filename);
534 error("It is recommended that your private key files are NOT accessible by others.");
535 error("This private key will be ignored.");
542 key_load_private_type(int type, const char *filename, const char *passphrase,
547 fd = open(filename, O_RDONLY);
550 if (!key_perm_ok(fd, filename)) {
551 error("bad permissions: ignore key: %s", filename);
557 return key_load_private_rsa1(fd, filename, passphrase,
564 return key_load_private_pem(fd, type, passphrase, commentp);
575 key_load_private(const char *filename, const char *passphrase,
581 fd = open(filename, O_RDONLY);
584 if (!key_perm_ok(fd, filename)) {
585 error("bad permissions: ignore key: %s", filename);
589 pub = key_load_public_rsa1(fd, filename, commentp);
590 lseek(fd, (off_t) 0, SEEK_SET); /* rewind */
593 prv = key_load_private_pem(fd, KEY_UNSPEC, passphrase, NULL);
594 /* use the filename as a comment for PEM */
596 *commentp = xstrdup(filename);
598 /* it's a SSH v1 key if the public key part is readable */
601 prv = key_load_private_rsa1(fd, filename, passphrase, NULL);
607 key_try_load_public(Key *k, const char *filename, char **commentp)
610 char line[SSH_MAX_PUBKEY_BYTES];
614 f = fopen(filename, "r");
616 while (read_keyfile_line(f, filename, line, sizeof(line),
625 /* Skip leading whitespace. */
626 for (; *cp && (*cp == ' ' || *cp == '\t'); cp++)
629 if (key_read(k, &cp) == 1) {
631 *commentp=xstrdup(filename);
642 /* load public key from ssh v1 private or any pubkey file */
644 key_load_public(const char *filename, char **commentp)
647 char file[MAXPATHLEN];
649 /* try rsa1 private key */
650 pub = key_load_public_type(KEY_RSA1, filename, commentp);
654 /* try rsa1 public key */
655 pub = key_new(KEY_RSA1);
656 if (key_try_load_public(pub, filename, commentp) == 1)
660 /* try ssh2 public key */
661 pub = key_new(KEY_UNSPEC);
662 if (key_try_load_public(pub, filename, commentp) == 1)
664 if ((strlcpy(file, filename, sizeof file) < sizeof(file)) &&
665 (strlcat(file, ".pub", sizeof file) < sizeof(file)) &&
666 (key_try_load_public(pub, file, commentp) == 1))