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 1.50 2002/06/24 14:55:38 markus Exp $");
42 #include <openssl/err.h>
43 #include <openssl/evp.h>
44 #include <openssl/pem.h>
56 /* Version identification string for SSH v1 identity files. */
57 static const char authfile_id_string[] =
58 "SSH PRIVATE KEY FILE FORMAT 1.1\n";
61 * Saves the authentication (private) key in a file, encrypting it with
62 * passphrase. The identification of the file (lowest 64 bits of n) will
63 * precede the key to provide identification of the key without needing a
68 key_save_private_rsa1(Key *key, const char *filename, const char *passphrase,
71 Buffer buffer, encrypted;
73 int fd, i, cipher_num;
74 CipherContext ciphercontext;
79 * If the passphrase is empty, use SSH_CIPHER_NONE to ease converting
80 * to another cipher; otherwise use SSH_AUTHFILE_CIPHER.
82 cipher_num = (strcmp(passphrase, "") == 0) ?
83 SSH_CIPHER_NONE : SSH_AUTHFILE_CIPHER;
84 if ((cipher = cipher_by_number(cipher_num)) == NULL)
85 fatal("save_private_key_rsa: bad cipher");
87 /* This buffer is used to built the secret part of the private key. */
90 /* Put checkbytes for checking passphrase validity. */
93 buf[1] = (rand >> 8) & 0xff;
96 buffer_append(&buffer, buf, 4);
99 * Store the private key (n and e will not be stored because they
100 * will be stored in plain text, and storing them also in encrypted
101 * format would just give known plaintext).
103 buffer_put_bignum(&buffer, key->rsa->d);
104 buffer_put_bignum(&buffer, key->rsa->iqmp);
105 buffer_put_bignum(&buffer, key->rsa->q); /* reverse from SSL p */
106 buffer_put_bignum(&buffer, key->rsa->p); /* reverse from SSL q */
108 /* Pad the part to be encrypted until its size is a multiple of 8. */
109 while (buffer_len(&buffer) % 8 != 0)
110 buffer_put_char(&buffer, 0);
112 /* This buffer will be used to contain the data in the file. */
113 buffer_init(&encrypted);
115 /* First store keyfile id string. */
116 for (i = 0; authfile_id_string[i]; i++)
117 buffer_put_char(&encrypted, authfile_id_string[i]);
118 buffer_put_char(&encrypted, 0);
120 /* Store cipher type. */
121 buffer_put_char(&encrypted, cipher_num);
122 buffer_put_int(&encrypted, 0); /* For future extension */
124 /* Store public key. This will be in plain text. */
125 buffer_put_int(&encrypted, BN_num_bits(key->rsa->n));
126 buffer_put_bignum(&encrypted, key->rsa->n);
127 buffer_put_bignum(&encrypted, key->rsa->e);
128 buffer_put_cstring(&encrypted, comment);
130 /* Allocate space for the private part of the key in the buffer. */
131 cp = buffer_append_space(&encrypted, buffer_len(&buffer));
133 cipher_set_key_string(&ciphercontext, cipher, passphrase,
135 cipher_crypt(&ciphercontext, cp,
136 buffer_ptr(&buffer), buffer_len(&buffer));
137 cipher_cleanup(&ciphercontext);
138 memset(&ciphercontext, 0, sizeof(ciphercontext));
140 /* Destroy temporary data. */
141 memset(buf, 0, sizeof(buf));
142 buffer_free(&buffer);
144 fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0600);
146 error("open %s failed: %s.", filename, strerror(errno));
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)
240 len = lseek(fd, (off_t) 0, SEEK_END);
241 lseek(fd, (off_t) 0, SEEK_SET);
243 buffer_init(&buffer);
244 cp = buffer_append_space(&buffer, len);
246 if (read(fd, cp, (size_t) len) != (size_t) len) {
247 debug("Read from key file %.200s failed: %.100s", filename,
249 buffer_free(&buffer);
253 /* Check that it is at least big enough to contain the ID string. */
254 if (len < sizeof(authfile_id_string)) {
255 debug3("Not a RSA1 key file %.200s.", filename);
256 buffer_free(&buffer);
260 * Make sure it begins with the id string. Consume the id string
263 for (i = 0; i < sizeof(authfile_id_string); i++)
264 if (buffer_get_char(&buffer) != authfile_id_string[i]) {
265 debug3("Not a RSA1 key file %.200s.", filename);
266 buffer_free(&buffer);
269 /* Skip cipher type and reserved data. */
270 (void) buffer_get_char(&buffer); /* cipher type */
271 (void) buffer_get_int(&buffer); /* reserved */
273 /* Read the public key from the buffer. */
274 (void) buffer_get_int(&buffer);
275 pub = key_new(KEY_RSA1);
276 buffer_get_bignum(&buffer, pub->rsa->n);
277 buffer_get_bignum(&buffer, pub->rsa->e);
279 *commentp = buffer_get_string(&buffer, NULL);
280 /* The encrypted private part is not parsed by this function. */
282 buffer_free(&buffer);
286 /* load public key from private-key file, works only for SSH v1 */
288 key_load_public_type(int type, const char *filename, char **commentp)
293 if (type == KEY_RSA1) {
294 fd = open(filename, O_RDONLY);
297 pub = key_load_public_rsa1(fd, filename, commentp);
305 * Loads the private key from the file. Returns 0 if an error is encountered
306 * (file does not exist or is not readable, or passphrase is bad). This
307 * initializes the private key.
308 * Assumes we are called under uid of the owner of the file.
312 key_load_private_rsa1(int fd, const char *filename, const char *passphrase,
315 int i, check1, check2, cipher_type;
317 Buffer buffer, decrypted;
319 CipherContext ciphercontext;
323 len = lseek(fd, (off_t) 0, SEEK_END);
324 lseek(fd, (off_t) 0, SEEK_SET);
326 buffer_init(&buffer);
327 cp = buffer_append_space(&buffer, len);
329 if (read(fd, cp, (size_t) len) != (size_t) len) {
330 debug("Read from key file %.200s failed: %.100s", filename,
332 buffer_free(&buffer);
337 /* Check that it is at least big enough to contain the ID string. */
338 if (len < sizeof(authfile_id_string)) {
339 debug3("Not a RSA1 key file %.200s.", filename);
340 buffer_free(&buffer);
345 * Make sure it begins with the id string. Consume the id string
348 for (i = 0; i < sizeof(authfile_id_string); i++)
349 if (buffer_get_char(&buffer) != authfile_id_string[i]) {
350 debug3("Not a RSA1 key file %.200s.", filename);
351 buffer_free(&buffer);
356 /* Read cipher type. */
357 cipher_type = buffer_get_char(&buffer);
358 (void) buffer_get_int(&buffer); /* Reserved data. */
360 /* Read the public key from the buffer. */
361 (void) buffer_get_int(&buffer);
362 prv = key_new_private(KEY_RSA1);
364 buffer_get_bignum(&buffer, prv->rsa->n);
365 buffer_get_bignum(&buffer, prv->rsa->e);
367 *commentp = buffer_get_string(&buffer, NULL);
369 xfree(buffer_get_string(&buffer, NULL));
371 /* Check that it is a supported cipher. */
372 cipher = cipher_by_number(cipher_type);
373 if (cipher == NULL) {
374 debug("Unsupported cipher %d used in key file %.200s.",
375 cipher_type, filename);
376 buffer_free(&buffer);
379 /* Initialize space for decrypted data. */
380 buffer_init(&decrypted);
381 cp = buffer_append_space(&decrypted, buffer_len(&buffer));
383 /* Rest of the buffer is encrypted. Decrypt it using the passphrase. */
384 cipher_set_key_string(&ciphercontext, cipher, passphrase,
386 cipher_crypt(&ciphercontext, cp,
387 buffer_ptr(&buffer), buffer_len(&buffer));
388 cipher_cleanup(&ciphercontext);
389 memset(&ciphercontext, 0, sizeof(ciphercontext));
390 buffer_free(&buffer);
392 check1 = buffer_get_char(&decrypted);
393 check2 = buffer_get_char(&decrypted);
394 if (check1 != buffer_get_char(&decrypted) ||
395 check2 != buffer_get_char(&decrypted)) {
396 if (strcmp(passphrase, "") != 0)
397 debug("Bad passphrase supplied for key file %.200s.",
399 /* Bad passphrase. */
400 buffer_free(&decrypted);
403 /* Read the rest of the private key. */
404 buffer_get_bignum(&decrypted, prv->rsa->d);
405 buffer_get_bignum(&decrypted, prv->rsa->iqmp); /* u */
406 /* in SSL and SSH v1 p and q are exchanged */
407 buffer_get_bignum(&decrypted, prv->rsa->q); /* p */
408 buffer_get_bignum(&decrypted, prv->rsa->p); /* q */
410 /* calculate p-1 and q-1 */
411 rsa_generate_additional_parameters(prv->rsa);
413 buffer_free(&decrypted);
426 key_load_private_pem(int fd, int type, const char *passphrase,
432 char *name = "<no key>";
434 fp = fdopen(fd, "r");
436 error("fdopen failed: %s", strerror(errno));
440 pk = PEM_read_PrivateKey(fp, NULL, NULL, (char *)passphrase);
442 debug("PEM_read_PrivateKey failed");
443 (void)ERR_get_error();
444 } else if (pk->type == EVP_PKEY_RSA &&
445 (type == KEY_UNSPEC||type==KEY_RSA)) {
446 prv = key_new(KEY_UNSPEC);
447 prv->rsa = EVP_PKEY_get1_RSA(pk);
449 name = "rsa w/o comment";
451 RSA_print_fp(stderr, prv->rsa, 8);
453 } else if (pk->type == EVP_PKEY_DSA &&
454 (type == KEY_UNSPEC||type==KEY_DSA)) {
455 prv = key_new(KEY_UNSPEC);
456 prv->dsa = EVP_PKEY_get1_DSA(pk);
458 name = "dsa w/o comment";
460 DSA_print_fp(stderr, prv->dsa, 8);
463 error("PEM_read_PrivateKey: mismatch or "
464 "unknown EVP_PKEY save_type %d", pk->save_type);
469 if (prv != NULL && commentp)
470 *commentp = xstrdup(name);
471 debug("read PEM private key done: type %s",
472 prv ? key_type(prv) : "<unknown>");
477 key_perm_ok(int fd, const char *filename)
481 if (fstat(fd, &st) < 0)
484 * if a key owned by the user is accessed, then we check the
485 * permissions of the file. if the key owned by a different user,
486 * then we don't care.
489 if (check_ntsec(filename))
491 if ((st.st_uid == getuid()) && (st.st_mode & 077) != 0) {
492 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
493 error("@ WARNING: UNPROTECTED PRIVATE KEY FILE! @");
494 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
495 error("Permissions 0%3.3o for '%s' are too open.",
496 st.st_mode & 0777, filename);
497 error("It is recommended that your private key files are NOT accessible by others.");
498 error("This private key will be ignored.");
505 key_load_private_type(int type, const char *filename, const char *passphrase,
510 fd = open(filename, O_RDONLY);
513 if (!key_perm_ok(fd, filename)) {
514 error("bad permissions: ignore key: %s", filename);
520 return key_load_private_rsa1(fd, filename, passphrase,
527 return key_load_private_pem(fd, type, passphrase, commentp);
538 key_load_private(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);
552 pub = key_load_public_rsa1(fd, filename, commentp);
553 lseek(fd, (off_t) 0, SEEK_SET); /* rewind */
556 prv = key_load_private_pem(fd, KEY_UNSPEC, passphrase, NULL);
557 /* use the filename as a comment for PEM */
559 *commentp = xstrdup(filename);
561 /* it's a SSH v1 key if the public key part is readable */
564 prv = key_load_private_rsa1(fd, filename, passphrase, NULL);
570 key_try_load_public(Key *k, const char *filename, char **commentp)
576 f = fopen(filename, "r");
578 while (fgets(line, sizeof(line), f)) {
579 line[sizeof(line)-1] = '\0';
587 /* Skip leading whitespace. */
588 for (; *cp && (*cp == ' ' || *cp == '\t'); cp++)
591 if (key_read(k, &cp) == 1) {
593 *commentp=xstrdup(filename);
604 /* load public key from ssh v1 private or any pubkey file */
606 key_load_public(const char *filename, char **commentp)
609 char file[MAXPATHLEN];
611 pub = key_load_public_type(KEY_RSA1, filename, commentp);
614 pub = key_new(KEY_UNSPEC);
615 if (key_try_load_public(pub, filename, commentp) == 1)
617 if ((strlcpy(file, filename, sizeof file) < sizeof(file)) &&
618 (strlcat(file, ".pub", sizeof file) < sizeof(file)) &&
619 (key_try_load_public(pub, file, commentp) == 1))