1 /* $OpenBSD: authfile.c,v 1.69 2006/07/11 20:27:56 stevesk Exp $ */
3 * Author: Tatu Ylonen <ylo@cs.hut.fi>
4 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
6 * This file contains functions for reading and writing identity files, and
7 * for reading the passphrase from the user.
9 * As far as I am concerned, the code I have written for this software
10 * can be used freely for any purpose. Any derived versions of this
11 * software must be clearly marked as such, and if the derived work is
12 * incompatible with the protocol description in the RFC file, it must be
13 * called by a name other than "ssh" or "Secure Shell".
16 * Copyright (c) 2000 Markus Friedl. All rights reserved.
18 * Redistribution and use in source and binary forms, with or without
19 * modification, are permitted provided that the following conditions
21 * 1. Redistributions of source code must retain the above copyright
22 * notice, this list of conditions and the following disclaimer.
23 * 2. Redistributions in binary form must reproduce the above copyright
24 * notice, this list of conditions and the following disclaimer in the
25 * documentation and/or other materials provided with the distribution.
27 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
28 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
29 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
30 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
31 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
32 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
33 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
34 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
35 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
36 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
41 #include <sys/types.h>
44 #include <openssl/err.h>
45 #include <openssl/evp.h>
46 #include <openssl/pem.h>
63 /* Version identification string for SSH v1 identity files. */
64 static const char authfile_id_string[] =
65 "SSH PRIVATE KEY FILE FORMAT 1.1\n";
68 * Saves the authentication (private) key in a file, encrypting it with
69 * passphrase. The identification of the file (lowest 64 bits of n) will
70 * precede the key to provide identification of the key without needing a
75 key_save_private_rsa1(Key *key, const char *filename, const char *passphrase,
78 Buffer buffer, encrypted;
80 int fd, i, cipher_num;
81 CipherContext ciphercontext;
86 * If the passphrase is empty, use SSH_CIPHER_NONE to ease converting
87 * to another cipher; otherwise use SSH_AUTHFILE_CIPHER.
89 cipher_num = (strcmp(passphrase, "") == 0) ?
90 SSH_CIPHER_NONE : SSH_AUTHFILE_CIPHER;
91 if ((cipher = cipher_by_number(cipher_num)) == NULL)
92 fatal("save_private_key_rsa: bad cipher");
94 /* This buffer is used to built the secret part of the private key. */
97 /* Put checkbytes for checking passphrase validity. */
100 buf[1] = (rnd >> 8) & 0xff;
103 buffer_append(&buffer, buf, 4);
106 * Store the private key (n and e will not be stored because they
107 * will be stored in plain text, and storing them also in encrypted
108 * format would just give known plaintext).
110 buffer_put_bignum(&buffer, key->rsa->d);
111 buffer_put_bignum(&buffer, key->rsa->iqmp);
112 buffer_put_bignum(&buffer, key->rsa->q); /* reverse from SSL p */
113 buffer_put_bignum(&buffer, key->rsa->p); /* reverse from SSL q */
115 /* Pad the part to be encrypted until its size is a multiple of 8. */
116 while (buffer_len(&buffer) % 8 != 0)
117 buffer_put_char(&buffer, 0);
119 /* This buffer will be used to contain the data in the file. */
120 buffer_init(&encrypted);
122 /* First store keyfile id string. */
123 for (i = 0; authfile_id_string[i]; i++)
124 buffer_put_char(&encrypted, authfile_id_string[i]);
125 buffer_put_char(&encrypted, 0);
127 /* Store cipher type. */
128 buffer_put_char(&encrypted, cipher_num);
129 buffer_put_int(&encrypted, 0); /* For future extension */
131 /* Store public key. This will be in plain text. */
132 buffer_put_int(&encrypted, BN_num_bits(key->rsa->n));
133 buffer_put_bignum(&encrypted, key->rsa->n);
134 buffer_put_bignum(&encrypted, key->rsa->e);
135 buffer_put_cstring(&encrypted, comment);
137 /* Allocate space for the private part of the key in the buffer. */
138 cp = buffer_append_space(&encrypted, buffer_len(&buffer));
140 cipher_set_key_string(&ciphercontext, cipher, passphrase,
142 cipher_crypt(&ciphercontext, cp,
143 buffer_ptr(&buffer), buffer_len(&buffer));
144 cipher_cleanup(&ciphercontext);
145 memset(&ciphercontext, 0, sizeof(ciphercontext));
147 /* Destroy temporary data. */
148 memset(buf, 0, sizeof(buf));
149 buffer_free(&buffer);
151 fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0600);
153 error("open %s failed: %s.", filename, strerror(errno));
154 buffer_free(&encrypted);
157 if (atomicio(vwrite, fd, buffer_ptr(&encrypted),
158 buffer_len(&encrypted)) != buffer_len(&encrypted)) {
159 error("write to key file %s failed: %s", filename,
161 buffer_free(&encrypted);
167 buffer_free(&encrypted);
171 /* save SSH v2 key in OpenSSL PEM format */
173 key_save_private_pem(Key *key, const char *filename, const char *_passphrase,
179 int len = strlen(_passphrase);
180 u_char *passphrase = (len > 0) ? (u_char *)_passphrase : NULL;
181 const EVP_CIPHER *cipher = (len > 0) ? EVP_des_ede3_cbc() : NULL;
183 if (len > 0 && len <= 4) {
184 error("passphrase too short: have %d bytes, need > 4", len);
187 fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0600);
189 error("open %s failed: %s.", filename, strerror(errno));
192 fp = fdopen(fd, "w");
194 error("fdopen %s failed: %s.", filename, strerror(errno));
200 success = PEM_write_DSAPrivateKey(fp, key->dsa,
201 cipher, passphrase, len, NULL, NULL);
204 success = PEM_write_RSAPrivateKey(fp, key->rsa,
205 cipher, passphrase, len, NULL, NULL);
213 key_save_private(Key *key, const char *filename, const char *passphrase,
218 return key_save_private_rsa1(key, filename, passphrase,
222 return key_save_private_pem(key, filename, passphrase,
227 error("key_save_private: cannot save key type %d", key->type);
232 * Loads the public part of the ssh v1 key file. Returns NULL if an error was
233 * encountered (the file does not exist or is not readable), and the key
238 key_load_public_rsa1(int fd, const char *filename, char **commentp)
247 if (fstat(fd, &st) < 0) {
248 error("fstat for key file %.200s failed: %.100s",
249 filename, strerror(errno));
252 if (st.st_size > 1*1024*1024) {
253 error("key file %.200s too large", filename);
256 len = (size_t)st.st_size; /* truncated */
258 buffer_init(&buffer);
259 cp = buffer_append_space(&buffer, len);
261 if (atomicio(read, fd, cp, len) != len) {
262 debug("Read from key file %.200s failed: %.100s", filename,
264 buffer_free(&buffer);
268 /* Check that it is at least big enough to contain the ID string. */
269 if (len < sizeof(authfile_id_string)) {
270 debug3("Not a RSA1 key file %.200s.", filename);
271 buffer_free(&buffer);
275 * Make sure it begins with the id string. Consume the id string
278 for (i = 0; i < sizeof(authfile_id_string); i++)
279 if (buffer_get_char(&buffer) != authfile_id_string[i]) {
280 debug3("Not a RSA1 key file %.200s.", filename);
281 buffer_free(&buffer);
284 /* Skip cipher type and reserved data. */
285 (void) buffer_get_char(&buffer); /* cipher type */
286 (void) buffer_get_int(&buffer); /* reserved */
288 /* Read the public key from the buffer. */
289 (void) buffer_get_int(&buffer);
290 pub = key_new(KEY_RSA1);
291 buffer_get_bignum(&buffer, pub->rsa->n);
292 buffer_get_bignum(&buffer, pub->rsa->e);
294 *commentp = buffer_get_string(&buffer, NULL);
295 /* The encrypted private part is not parsed by this function. */
297 buffer_free(&buffer);
301 /* load public key from private-key file, works only for SSH v1 */
303 key_load_public_type(int type, const char *filename, char **commentp)
308 if (type == KEY_RSA1) {
309 fd = open(filename, O_RDONLY);
312 pub = key_load_public_rsa1(fd, filename, commentp);
320 * Loads the private key from the file. Returns 0 if an error is encountered
321 * (file does not exist or is not readable, or passphrase is bad). This
322 * initializes the private key.
323 * Assumes we are called under uid of the owner of the file.
327 key_load_private_rsa1(int fd, const char *filename, const char *passphrase,
331 int check1, check2, cipher_type;
333 Buffer buffer, decrypted;
335 CipherContext ciphercontext;
340 if (fstat(fd, &st) < 0) {
341 error("fstat for key file %.200s failed: %.100s",
342 filename, strerror(errno));
346 if (st.st_size > 1*1024*1024) {
347 error("key file %.200s too large", filename);
351 len = (size_t)st.st_size; /* truncated */
353 buffer_init(&buffer);
354 cp = buffer_append_space(&buffer, len);
356 if (atomicio(read, fd, cp, len) != len) {
357 debug("Read from key file %.200s failed: %.100s", filename,
359 buffer_free(&buffer);
364 /* Check that it is at least big enough to contain the ID string. */
365 if (len < sizeof(authfile_id_string)) {
366 debug3("Not a RSA1 key file %.200s.", filename);
367 buffer_free(&buffer);
372 * Make sure it begins with the id string. Consume the id string
375 for (i = 0; i < sizeof(authfile_id_string); i++)
376 if (buffer_get_char(&buffer) != authfile_id_string[i]) {
377 debug3("Not a RSA1 key file %.200s.", filename);
378 buffer_free(&buffer);
383 /* Read cipher type. */
384 cipher_type = buffer_get_char(&buffer);
385 (void) buffer_get_int(&buffer); /* Reserved data. */
387 /* Read the public key from the buffer. */
388 (void) buffer_get_int(&buffer);
389 prv = key_new_private(KEY_RSA1);
391 buffer_get_bignum(&buffer, prv->rsa->n);
392 buffer_get_bignum(&buffer, prv->rsa->e);
394 *commentp = buffer_get_string(&buffer, NULL);
396 xfree(buffer_get_string(&buffer, NULL));
398 /* Check that it is a supported cipher. */
399 cipher = cipher_by_number(cipher_type);
400 if (cipher == NULL) {
401 debug("Unsupported cipher %d used in key file %.200s.",
402 cipher_type, filename);
403 buffer_free(&buffer);
406 /* Initialize space for decrypted data. */
407 buffer_init(&decrypted);
408 cp = buffer_append_space(&decrypted, buffer_len(&buffer));
410 /* Rest of the buffer is encrypted. Decrypt it using the passphrase. */
411 cipher_set_key_string(&ciphercontext, cipher, passphrase,
413 cipher_crypt(&ciphercontext, cp,
414 buffer_ptr(&buffer), buffer_len(&buffer));
415 cipher_cleanup(&ciphercontext);
416 memset(&ciphercontext, 0, sizeof(ciphercontext));
417 buffer_free(&buffer);
419 check1 = buffer_get_char(&decrypted);
420 check2 = buffer_get_char(&decrypted);
421 if (check1 != buffer_get_char(&decrypted) ||
422 check2 != buffer_get_char(&decrypted)) {
423 if (strcmp(passphrase, "") != 0)
424 debug("Bad passphrase supplied for key file %.200s.",
426 /* Bad passphrase. */
427 buffer_free(&decrypted);
430 /* Read the rest of the private key. */
431 buffer_get_bignum(&decrypted, prv->rsa->d);
432 buffer_get_bignum(&decrypted, prv->rsa->iqmp); /* u */
433 /* in SSL and SSH v1 p and q are exchanged */
434 buffer_get_bignum(&decrypted, prv->rsa->q); /* p */
435 buffer_get_bignum(&decrypted, prv->rsa->p); /* q */
437 /* calculate p-1 and q-1 */
438 rsa_generate_additional_parameters(prv->rsa);
440 buffer_free(&decrypted);
442 /* enable blinding */
443 if (RSA_blinding_on(prv->rsa, NULL) != 1) {
444 error("key_load_private_rsa1: RSA_blinding_on failed");
459 key_load_private_pem(int fd, int type, const char *passphrase,
465 char *name = "<no key>";
467 fp = fdopen(fd, "r");
469 error("fdopen failed: %s", strerror(errno));
473 pk = PEM_read_PrivateKey(fp, NULL, NULL, (char *)passphrase);
475 debug("PEM_read_PrivateKey failed");
476 (void)ERR_get_error();
477 } else if (pk->type == EVP_PKEY_RSA &&
478 (type == KEY_UNSPEC||type==KEY_RSA)) {
479 prv = key_new(KEY_UNSPEC);
480 prv->rsa = EVP_PKEY_get1_RSA(pk);
482 name = "rsa w/o comment";
484 RSA_print_fp(stderr, prv->rsa, 8);
486 if (RSA_blinding_on(prv->rsa, NULL) != 1) {
487 error("key_load_private_pem: RSA_blinding_on failed");
491 } else if (pk->type == EVP_PKEY_DSA &&
492 (type == KEY_UNSPEC||type==KEY_DSA)) {
493 prv = key_new(KEY_UNSPEC);
494 prv->dsa = EVP_PKEY_get1_DSA(pk);
496 name = "dsa w/o comment";
498 DSA_print_fp(stderr, prv->dsa, 8);
501 error("PEM_read_PrivateKey: mismatch or "
502 "unknown EVP_PKEY save_type %d", pk->save_type);
507 if (prv != NULL && commentp)
508 *commentp = xstrdup(name);
509 debug("read PEM private key done: type %s",
510 prv ? key_type(prv) : "<unknown>");
515 key_perm_ok(int fd, const char *filename)
519 if (fstat(fd, &st) < 0)
522 * if a key owned by the user is accessed, then we check the
523 * permissions of the file. if the key owned by a different user,
524 * then we don't care.
527 if (check_ntsec(filename))
529 if ((st.st_uid == getuid()) && (st.st_mode & 077) != 0) {
530 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
531 error("@ WARNING: UNPROTECTED PRIVATE KEY FILE! @");
532 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
533 error("Permissions 0%3.3o for '%s' are too open.",
534 (u_int)st.st_mode & 0777, filename);
535 error("It is recommended that your private key files are NOT accessible by others.");
536 error("This private key will be ignored.");
543 key_load_private_type(int type, const char *filename, const char *passphrase,
544 char **commentp, int *perm_ok)
548 fd = open(filename, O_RDONLY);
551 if (!key_perm_ok(fd, filename)) {
554 error("bad permissions: ignore key: %s", filename);
562 return key_load_private_rsa1(fd, filename, passphrase,
568 return key_load_private_pem(fd, type, passphrase, commentp);
578 key_load_private(const char *filename, const char *passphrase,
584 fd = open(filename, O_RDONLY);
587 if (!key_perm_ok(fd, filename)) {
588 error("bad permissions: ignore key: %s", filename);
592 pub = key_load_public_rsa1(fd, filename, commentp);
593 lseek(fd, (off_t) 0, SEEK_SET); /* rewind */
596 prv = key_load_private_pem(fd, KEY_UNSPEC, passphrase, NULL);
597 /* use the filename as a comment for PEM */
599 *commentp = xstrdup(filename);
601 /* it's a SSH v1 key if the public key part is readable */
604 prv = key_load_private_rsa1(fd, filename, passphrase, NULL);
610 key_try_load_public(Key *k, const char *filename, char **commentp)
613 char line[SSH_MAX_PUBKEY_BYTES];
617 f = fopen(filename, "r");
619 while (read_keyfile_line(f, filename, line, sizeof(line),
628 /* Skip leading whitespace. */
629 for (; *cp && (*cp == ' ' || *cp == '\t'); cp++)
632 if (key_read(k, &cp) == 1) {
634 *commentp=xstrdup(filename);
645 /* load public key from ssh v1 private or any pubkey file */
647 key_load_public(const char *filename, char **commentp)
650 char file[MAXPATHLEN];
652 /* try rsa1 private key */
653 pub = key_load_public_type(KEY_RSA1, filename, commentp);
657 /* try rsa1 public key */
658 pub = key_new(KEY_RSA1);
659 if (key_try_load_public(pub, filename, commentp) == 1)
663 /* try ssh2 public key */
664 pub = key_new(KEY_UNSPEC);
665 if (key_try_load_public(pub, filename, commentp) == 1)
667 if ((strlcpy(file, filename, sizeof file) < sizeof(file)) &&
668 (strlcat(file, ".pub", sizeof file) < sizeof(file)) &&
669 (key_try_load_public(pub, file, commentp) == 1))