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 1.24 2000/12/20 19:26:56 markus Exp $");
41 #include <openssl/bn.h>
42 #include <openssl/dsa.h>
43 #include <openssl/rsa.h>
44 #include <openssl/err.h>
45 #include <openssl/pem.h>
46 #include <openssl/evp.h>
54 /* Version identification string for identity files. */
55 #define AUTHFILE_ID_STRING "SSH PRIVATE KEY FILE FORMAT 1.1\n"
58 * Saves the authentication (private) key in a file, encrypting it with
59 * passphrase. The identification of the file (lowest 64 bits of n) will
60 * precede the key to provide identification of the key without needing a
65 save_private_key_rsa1(const char *filename, const char *passphrase,
66 RSA *key, const char *comment)
68 Buffer buffer, encrypted;
71 CipherContext ciphercontext;
76 * If the passphrase is empty, use SSH_CIPHER_NONE to ease converting
77 * to another cipher; otherwise use SSH_AUTHFILE_CIPHER.
79 if (strcmp(passphrase, "") == 0)
80 cipher = cipher_by_number(SSH_CIPHER_NONE);
82 cipher = cipher_by_number(SSH_AUTHFILE_CIPHER);
84 fatal("save_private_key_rsa: bad cipher");
86 /* This buffer is used to built the secret part of the private key. */
89 /* Put checkbytes for checking passphrase validity. */
92 buf[1] = (rand >> 8) & 0xff;
95 buffer_append(&buffer, buf, 4);
98 * Store the private key (n and e will not be stored because they
99 * will be stored in plain text, and storing them also in encrypted
100 * format would just give known plaintext).
102 buffer_put_bignum(&buffer, key->d);
103 buffer_put_bignum(&buffer, key->iqmp);
104 buffer_put_bignum(&buffer, key->q); /* reverse from SSL p */
105 buffer_put_bignum(&buffer, key->p); /* reverse from SSL q */
107 /* Pad the part to be encrypted until its size is a multiple of 8. */
108 while (buffer_len(&buffer) % 8 != 0)
109 buffer_put_char(&buffer, 0);
111 /* This buffer will be used to contain the data in the file. */
112 buffer_init(&encrypted);
114 /* First store keyfile id string. */
115 cp = AUTHFILE_ID_STRING;
116 for (i = 0; cp[i]; i++)
117 buffer_put_char(&encrypted, cp[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->n));
126 buffer_put_bignum(&encrypted, key->n);
127 buffer_put_bignum(&encrypted, key->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 SSH2 key in OpenSSL PEM format */
161 save_private_key_ssh2(const char *filename, const char *_passphrase,
162 Key *key, const char *comment)
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 save_private_key(const char *filename, const char *passphrase, Key *key,
207 return save_private_key_rsa1(filename, passphrase, key->rsa, comment);
211 return save_private_key_ssh2(filename, passphrase, key, comment);
220 * Loads the public part of the key file. Returns 0 if an error was
221 * encountered (the file does not exist or is not readable), and non-zero
226 load_public_key_rsa(const char *filename, RSA * pub, char **comment_return)
233 fd = open(filename, O_RDONLY);
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);
251 /* Check that it is at least big enought to contain the ID string. */
252 if (len < strlen(AUTHFILE_ID_STRING) + 1) {
253 debug3("Bad RSA1 key file %.200s.", filename);
254 buffer_free(&buffer);
258 * Make sure it begins with the id string. Consume the id string
261 for (i = 0; i < (u_int) strlen(AUTHFILE_ID_STRING) + 1; i++)
262 if (buffer_get_char(&buffer) != (u_char) AUTHFILE_ID_STRING[i]) {
263 debug3("Bad RSA1 key file %.200s.", filename);
264 buffer_free(&buffer);
267 /* Skip cipher type and reserved data. */
268 (void) buffer_get_char(&buffer); /* cipher type */
269 (void) buffer_get_int(&buffer); /* reserved */
271 /* Read the public key from the buffer. */
272 buffer_get_int(&buffer);
276 buffer_get_bignum(&buffer, pub->n);
280 buffer_get_bignum(&buffer, pub->e);
282 *comment_return = buffer_get_string(&buffer, NULL);
283 /* The encrypted private part is not parsed by this function. */
285 buffer_free(&buffer);
290 /* load public key from private-key file */
292 load_public_key(const char *filename, Key * key, char **comment_return)
296 return load_public_key_rsa(filename, key->rsa, comment_return);
307 * Loads the private key from the file. Returns 0 if an error is encountered
308 * (file does not exist or is not readable, or passphrase is bad). This
309 * initializes the private key.
310 * Assumes we are called under uid of the owner of the file.
314 load_private_key_rsa1(int fd, const char *filename,
315 const char *passphrase, RSA * prv, char **comment_return)
317 int i, check1, check2, cipher_type;
319 Buffer buffer, decrypted;
321 CipherContext ciphercontext;
326 len = lseek(fd, (off_t) 0, SEEK_END);
327 lseek(fd, (off_t) 0, SEEK_SET);
329 buffer_init(&buffer);
330 buffer_append_space(&buffer, &cp, len);
332 if (read(fd, cp, (size_t) len) != (size_t) len) {
333 debug("Read from key file %.200s failed: %.100s", filename,
335 buffer_free(&buffer);
341 /* Check that it is at least big enought to contain the ID string. */
342 if (len < strlen(AUTHFILE_ID_STRING) + 1) {
343 debug3("Bad RSA1 key file %.200s.", filename);
344 buffer_free(&buffer);
348 * Make sure it begins with the id string. Consume the id string
351 for (i = 0; i < (u_int) strlen(AUTHFILE_ID_STRING) + 1; i++)
352 if (buffer_get_char(&buffer) != (u_char) AUTHFILE_ID_STRING[i]) {
353 debug3("Bad RSA1 key file %.200s.", filename);
354 buffer_free(&buffer);
357 /* Read cipher type. */
358 cipher_type = buffer_get_char(&buffer);
359 (void) buffer_get_int(&buffer); /* Reserved data. */
361 /* Read the public key from the buffer. */
362 buffer_get_int(&buffer);
364 buffer_get_bignum(&buffer, prv->n);
366 buffer_get_bignum(&buffer, prv->e);
368 *comment_return = buffer_get_string(&buffer, NULL);
370 xfree(buffer_get_string(&buffer, NULL));
372 /* Check that it is a supported cipher. */
373 cipher = cipher_by_number(cipher_type);
374 if (cipher == NULL) {
375 debug("Unsupported cipher %d used in key file %.200s.",
376 cipher_type, filename);
377 buffer_free(&buffer);
380 /* Initialize space for decrypted data. */
381 buffer_init(&decrypted);
382 buffer_append_space(&decrypted, &cp, buffer_len(&buffer));
384 /* Rest of the buffer is encrypted. Decrypt it using the passphrase. */
385 cipher_set_key_string(&ciphercontext, cipher, passphrase);
386 cipher_decrypt(&ciphercontext, (u_char *) cp,
387 (u_char *) buffer_ptr(&buffer), buffer_len(&buffer));
388 memset(&ciphercontext, 0, sizeof(ciphercontext));
389 buffer_free(&buffer);
391 check1 = buffer_get_char(&decrypted);
392 check2 = buffer_get_char(&decrypted);
393 if (check1 != buffer_get_char(&decrypted) ||
394 check2 != buffer_get_char(&decrypted)) {
395 if (strcmp(passphrase, "") != 0)
396 debug("Bad passphrase supplied for key file %.200s.", filename);
397 /* Bad passphrase. */
398 buffer_free(&decrypted);
400 BN_clear_free(prv->n);
402 BN_clear_free(prv->e);
405 xfree(*comment_return);
408 /* Read the rest of the private key. */
410 buffer_get_bignum(&decrypted, prv->d);
411 prv->iqmp = BN_new();
412 buffer_get_bignum(&decrypted, prv->iqmp); /* u */
413 /* in SSL and SSH p and q are exchanged */
415 buffer_get_bignum(&decrypted, prv->q); /* p */
417 buffer_get_bignum(&decrypted, prv->p); /* q */
422 BN_sub(aux, prv->q, BN_value_one());
423 prv->dmq1 = BN_new();
424 BN_mod(prv->dmq1, prv->d, aux, ctx);
426 BN_sub(aux, prv->p, BN_value_one());
427 prv->dmp1 = BN_new();
428 BN_mod(prv->dmp1, prv->d, aux, ctx);
433 buffer_free(&decrypted);
439 load_private_key_ssh2(int fd, const char *passphrase, Key *k, char **comment_return)
444 char *name = "<no key>";
446 fp = fdopen(fd, "r");
448 error("fdopen failed");
451 pk = PEM_read_PrivateKey(fp, NULL, NULL, (char *)passphrase);
453 debug("PEM_read_PrivateKey failed");
454 (void)ERR_get_error();
455 } else if (pk->type == EVP_PKEY_RSA) {
456 /* replace k->rsa with loaded key */
457 if (k->type == KEY_RSA || k->type == KEY_UNSPEC) {
460 k->rsa = EVP_PKEY_get1_RSA(pk);
462 name = "rsa w/o comment";
465 RSA_print_fp(stderr, k->rsa, 8);
468 } else if (pk->type == EVP_PKEY_DSA) {
469 /* replace k->dsa with loaded key */
470 if (k->type == KEY_DSA || k->type == KEY_UNSPEC) {
473 k->dsa = EVP_PKEY_get1_DSA(pk);
475 name = "dsa w/o comment";
477 DSA_print_fp(stderr, k->dsa, 8);
482 error("PEM_read_PrivateKey: mismatch or "
483 "unknown EVP_PKEY save_type %d", pk->save_type);
488 if (success && comment_return)
489 *comment_return = xstrdup(name);
490 debug("read SSH2 private key done: name %s success %d", name, success);
495 load_private_key(const char *filename, const char *passphrase, Key *key,
496 char **comment_return)
502 fd = open(filename, O_RDONLY);
506 /* check owner and modes */
508 if (check_ntsec(filename))
510 if (fstat(fd, &st) < 0 ||
511 (st.st_uid != 0 && getuid() != 0 && st.st_uid != getuid()) ||
512 (st.st_mode & 077) != 0) {
514 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
515 error("@ WARNING: UNPROTECTED PRIVATE KEY FILE! @");
516 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
517 error("Bad ownership or mode(0%3.3o) for '%s'.",
518 st.st_mode & 0777, filename);
519 error("It is recommended that your private key files are NOT accessible by others.");
524 if (key->rsa->e != NULL) {
525 BN_clear_free(key->rsa->e);
528 if (key->rsa->n != NULL) {
529 BN_clear_free(key->rsa->n);
532 ret = load_private_key_rsa1(fd, filename, passphrase,
533 key->rsa, comment_return);
538 ret = load_private_key_ssh2(fd, passphrase, key, comment_return);
547 do_load_public_key(const char *filename, Key *k, char **commentp)
553 f = fopen(filename, "r");
555 while (fgets(line, sizeof(line), f)) {
556 line[sizeof(line)-1] = '\0';
564 /* Skip leading whitespace. */
565 for (; *cp && (*cp == ' ' || *cp == '\t'); cp++)
568 if (key_read(k, &cp) == 1) {
570 *commentp=xstrdup(filename);
581 /* load public key from pubkey file */
583 try_load_public_key(const char *filename, Key *k, char **commentp)
585 char pub[MAXPATHLEN];
587 if (do_load_public_key(filename, k, commentp) == 1)
589 if (strlcpy(pub, filename, sizeof pub) >= MAXPATHLEN)
591 if (strlcat(pub, ".pub", sizeof pub) >= MAXPATHLEN)
593 if (do_load_public_key(pub, k, commentp) == 1)