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 1.30 2001/03/26 23:12:42 markus Exp $");
41 #include <openssl/err.h>
42 #include <openssl/evp.h>
43 #include <openssl/pem.h>
54 /* Version identification string for SSH v1 identity files. */
55 static const char authfile_id_string[] =
56 "SSH PRIVATE KEY FILE FORMAT 1.1\n";
59 * Saves the authentication (private) key in a file, encrypting it with
60 * passphrase. The identification of the file (lowest 64 bits of n) will
61 * precede the key to provide identification of the key without needing a
66 key_save_private_rsa1(Key *key, const char *filename, const char *passphrase,
69 Buffer buffer, encrypted;
72 CipherContext ciphercontext;
77 * If the passphrase is empty, use SSH_CIPHER_NONE to ease converting
78 * to another cipher; otherwise use SSH_AUTHFILE_CIPHER.
80 if (strcmp(passphrase, "") == 0)
81 cipher = cipher_by_number(SSH_CIPHER_NONE);
83 cipher = cipher_by_number(SSH_AUTHFILE_CIPHER);
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->number);
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_string(&encrypted, comment, strlen(comment));
130 /* Allocate space for the private part of the key in the buffer. */
131 buffer_append_space(&encrypted, &cp, buffer_len(&buffer));
133 cipher_set_key_string(&ciphercontext, cipher, passphrase);
134 cipher_encrypt(&ciphercontext, (u_char *) cp,
135 (u_char *) buffer_ptr(&buffer), buffer_len(&buffer));
136 memset(&ciphercontext, 0, sizeof(ciphercontext));
138 /* Destroy temporary data. */
139 memset(buf, 0, sizeof(buf));
140 buffer_free(&buffer);
142 fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0600);
145 if (write(fd, buffer_ptr(&encrypted), buffer_len(&encrypted)) !=
146 buffer_len(&encrypted)) {
147 debug("Write to key file %.200s failed: %.100s", filename,
149 buffer_free(&encrypted);
155 buffer_free(&encrypted);
159 /* save SSH v2 key in OpenSSL PEM format */
161 key_save_private_pem(Key *key, const char *filename, const char *_passphrase,
167 int len = strlen(_passphrase);
168 char *passphrase = (len > 0) ? (char *)_passphrase : NULL;
169 EVP_CIPHER *cipher = (len > 0) ? EVP_des_ede3_cbc() : NULL;
171 if (len > 0 && len <= 4) {
172 error("passphrase too short: %d bytes", len);
176 fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0600);
178 debug("open %s failed", filename);
181 fp = fdopen(fd, "w");
183 debug("fdopen %s failed", filename);
189 success = PEM_write_DSAPrivateKey(fp, key->dsa,
190 cipher, passphrase, len, NULL, NULL);
193 success = PEM_write_RSAPrivateKey(fp, key->rsa,
194 cipher, passphrase, len, NULL, NULL);
202 key_save_private(Key *key, const char *filename, const char *passphrase,
207 return key_save_private_rsa1(key, filename, passphrase,
212 return key_save_private_pem(key, filename, passphrase,
222 * Loads the public part of the ssh v1 key file. Returns NULL if an error was
223 * encountered (the file does not exist or is not readable), and the key
228 key_load_public_rsa1(int fd, const char *filename, char **commentp)
236 len = lseek(fd, (off_t) 0, SEEK_END);
237 lseek(fd, (off_t) 0, SEEK_SET);
239 buffer_init(&buffer);
240 buffer_append_space(&buffer, &cp, len);
242 if (read(fd, cp, (size_t) len) != (size_t) len) {
243 debug("Read from key file %.200s failed: %.100s", filename,
245 buffer_free(&buffer);
249 /* Check that it is at least big enough to contain the ID string. */
250 if (len < sizeof(authfile_id_string)) {
251 debug3("Bad RSA1 key file %.200s.", filename);
252 buffer_free(&buffer);
256 * Make sure it begins with the id string. Consume the id string
259 for (i = 0; i < sizeof(authfile_id_string); i++)
260 if (buffer_get_char(&buffer) != authfile_id_string[i]) {
261 debug3("Bad RSA1 key file %.200s.", filename);
262 buffer_free(&buffer);
265 /* Skip cipher type and reserved data. */
266 (void) buffer_get_char(&buffer); /* cipher type */
267 (void) buffer_get_int(&buffer); /* reserved */
269 /* Read the public key from the buffer. */
270 buffer_get_int(&buffer);
271 pub = key_new(KEY_RSA1);
272 buffer_get_bignum(&buffer, pub->rsa->n);
273 buffer_get_bignum(&buffer, pub->rsa->e);
275 *commentp = buffer_get_string(&buffer, NULL);
276 /* The encrypted private part is not parsed by this function. */
278 buffer_free(&buffer);
282 /* load public key from private-key file, works only for SSH v1 */
284 key_load_public_type(int type, const char *filename, char **commentp)
289 if (type == KEY_RSA1) {
290 fd = open(filename, O_RDONLY);
293 pub = key_load_public_rsa1(fd, filename, commentp);
301 * Loads the private key from the file. Returns 0 if an error is encountered
302 * (file does not exist or is not readable, or passphrase is bad). This
303 * initializes the private key.
304 * Assumes we are called under uid of the owner of the file.
308 key_load_private_rsa1(int fd, const char *filename, const char *passphrase,
311 int i, check1, check2, cipher_type;
313 Buffer buffer, decrypted;
315 CipherContext ciphercontext;
321 len = lseek(fd, (off_t) 0, SEEK_END);
322 lseek(fd, (off_t) 0, SEEK_SET);
324 buffer_init(&buffer);
325 buffer_append_space(&buffer, &cp, len);
327 if (read(fd, cp, (size_t) len) != (size_t) len) {
328 debug("Read from key file %.200s failed: %.100s", filename,
330 buffer_free(&buffer);
335 /* Check that it is at least big enough to contain the ID string. */
336 if (len < sizeof(authfile_id_string)) {
337 debug3("Bad RSA1 key file %.200s.", filename);
338 buffer_free(&buffer);
343 * Make sure it begins with the id string. Consume the id string
346 for (i = 0; i < sizeof(authfile_id_string); i++)
347 if (buffer_get_char(&buffer) != authfile_id_string[i]) {
348 debug3("Bad RSA1 key file %.200s.", filename);
349 buffer_free(&buffer);
354 /* Read cipher type. */
355 cipher_type = buffer_get_char(&buffer);
356 (void) buffer_get_int(&buffer); /* Reserved data. */
358 /* Read the public key from the buffer. */
359 buffer_get_int(&buffer);
360 prv = key_new_private(KEY_RSA1);
362 buffer_get_bignum(&buffer, prv->rsa->n);
363 buffer_get_bignum(&buffer, prv->rsa->e);
365 *commentp = buffer_get_string(&buffer, NULL);
367 xfree(buffer_get_string(&buffer, NULL));
369 /* Check that it is a supported cipher. */
370 cipher = cipher_by_number(cipher_type);
371 if (cipher == NULL) {
372 debug("Unsupported cipher %d used in key file %.200s.",
373 cipher_type, filename);
374 buffer_free(&buffer);
377 /* Initialize space for decrypted data. */
378 buffer_init(&decrypted);
379 buffer_append_space(&decrypted, &cp, buffer_len(&buffer));
381 /* Rest of the buffer is encrypted. Decrypt it using the passphrase. */
382 cipher_set_key_string(&ciphercontext, cipher, passphrase);
383 cipher_decrypt(&ciphercontext, (u_char *) cp,
384 (u_char *) buffer_ptr(&buffer), buffer_len(&buffer));
385 memset(&ciphercontext, 0, sizeof(ciphercontext));
386 buffer_free(&buffer);
388 check1 = buffer_get_char(&decrypted);
389 check2 = buffer_get_char(&decrypted);
390 if (check1 != buffer_get_char(&decrypted) ||
391 check2 != buffer_get_char(&decrypted)) {
392 if (strcmp(passphrase, "") != 0)
393 debug("Bad passphrase supplied for key file %.200s.",
395 /* Bad passphrase. */
396 buffer_free(&decrypted);
399 /* Read the rest of the private key. */
400 buffer_get_bignum(&decrypted, prv->rsa->d);
401 buffer_get_bignum(&decrypted, prv->rsa->iqmp); /* u */
402 /* in SSL and SSH v1 p and q are exchanged */
403 buffer_get_bignum(&decrypted, prv->rsa->q); /* p */
404 buffer_get_bignum(&decrypted, prv->rsa->p); /* q */
406 /* calculate p-1 and q-1 */
410 BN_sub(aux, prv->rsa->q, BN_value_one());
411 BN_mod(prv->rsa->dmq1, prv->rsa->d, aux, ctx);
413 BN_sub(aux, prv->rsa->p, BN_value_one());
414 BN_mod(prv->rsa->dmp1, prv->rsa->d, aux, ctx);
419 buffer_free(&decrypted);
432 key_load_private_pem(int fd, int type, const char *passphrase,
438 char *name = "<no key>";
440 fp = fdopen(fd, "r");
442 error("fdopen failed");
446 pk = PEM_read_PrivateKey(fp, NULL, NULL, (char *)passphrase);
448 debug("PEM_read_PrivateKey failed");
449 (void)ERR_get_error();
450 } else if (pk->type == EVP_PKEY_RSA &&
451 (type == KEY_UNSPEC||type==KEY_RSA)) {
452 prv = key_new(KEY_UNSPEC);
453 prv->rsa = EVP_PKEY_get1_RSA(pk);
455 name = "rsa w/o comment";
457 RSA_print_fp(stderr, prv->rsa, 8);
459 } else if (pk->type == EVP_PKEY_DSA &&
460 (type == KEY_UNSPEC||type==KEY_DSA)) {
461 prv = key_new(KEY_UNSPEC);
462 prv->dsa = EVP_PKEY_get1_DSA(pk);
464 name = "dsa w/o comment";
466 DSA_print_fp(stderr, prv->dsa, 8);
469 error("PEM_read_PrivateKey: mismatch or "
470 "unknown EVP_PKEY save_type %d", pk->save_type);
475 if (prv != NULL && commentp)
476 *commentp = xstrdup(name);
477 debug("read PEM private key done: type %s",
478 prv ? key_type(prv) : "<unknown>");
483 key_perm_ok(int fd, const char *filename)
487 /* check owner and modes */
489 if (check_ntsec(filename))
491 if (fstat(fd, &st) < 0 ||
492 (st.st_uid != 0 && getuid() != 0 && st.st_uid != getuid()) ||
493 (st.st_mode & 077) != 0) {
495 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
496 error("@ WARNING: UNPROTECTED PRIVATE KEY FILE! @");
497 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
498 error("Bad ownership or mode(0%3.3o) for '%s'.",
499 st.st_mode & 0777, filename);
500 error("It is recommended that your private key files are NOT accessible by others.");
501 error("This private key will be ignored.");
508 key_load_private_type(int type, const char *filename, const char *passphrase,
513 fd = open(filename, O_RDONLY);
516 if (!key_perm_ok(fd, filename)) {
517 debug("bad permissions: ignore key: %s", filename);
523 return key_load_private_rsa1(fd, filename, passphrase,
530 return key_load_private_pem(fd, type, passphrase, commentp);
541 key_load_private(const char *filename, const char *passphrase,
547 fd = open(filename, O_RDONLY);
550 if (!key_perm_ok(fd, filename)) {
551 debug("bad permissions: ignore key: %s", filename);
555 pub = key_load_public_rsa1(fd, filename, commentp);
556 lseek(fd, (off_t) 0, SEEK_SET); /* rewind */
559 return key_load_private_pem(fd, KEY_UNSPEC, passphrase, NULL);
561 /* it's a SSH v1 key if the public key part is readable */
564 return key_load_private_rsa1(fd, filename, passphrase, NULL);
569 key_try_load_public(Key *k, const char *filename, char **commentp)
575 f = fopen(filename, "r");
577 while (fgets(line, sizeof(line), f)) {
578 line[sizeof(line)-1] = '\0';
586 /* Skip leading whitespace. */
587 for (; *cp && (*cp == ' ' || *cp == '\t'); cp++)
590 if (key_read(k, &cp) == 1) {
592 *commentp=xstrdup(filename);
603 /* load public key from ssh v1 private or any pubkey file */
605 key_load_public(const char *filename, char **commentp)
608 char file[MAXPATHLEN];
610 pub = key_load_public_type(KEY_RSA1, filename, commentp);
613 pub = key_new(KEY_UNSPEC);
614 if (key_try_load_public(pub, filename, commentp) == 1)
616 if ((strlcpy(file, filename, sizeof file) < sizeof(file)) &&
617 (strlcat(file, ".pub", sizeof file) < sizeof(file)) &&
618 (key_try_load_public(pub, file, commentp) == 1))