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 1.32 2001/04/18 23:44:51 markus Exp $");
42 #include <openssl/err.h>
43 #include <openssl/evp.h>
44 #include <openssl/pem.h>
55 /* Version identification string for SSH v1 identity files. */
56 static const char authfile_id_string[] =
57 "SSH PRIVATE KEY FILE FORMAT 1.1\n";
60 * Saves the authentication (private) key in a file, encrypting it with
61 * passphrase. The identification of the file (lowest 64 bits of n) will
62 * precede the key to provide identification of the key without needing a
67 key_save_private_rsa1(Key *key, const char *filename, const char *passphrase,
70 Buffer buffer, encrypted;
73 CipherContext ciphercontext;
78 * If the passphrase is empty, use SSH_CIPHER_NONE to ease converting
79 * to another cipher; otherwise use SSH_AUTHFILE_CIPHER.
81 if (strcmp(passphrase, "") == 0)
82 cipher = cipher_by_number(SSH_CIPHER_NONE);
84 cipher = cipher_by_number(SSH_AUTHFILE_CIPHER);
86 fatal("save_private_key_rsa: bad cipher");
88 /* This buffer is used to built the secret part of the private key. */
91 /* Put checkbytes for checking passphrase validity. */
94 buf[1] = (rand >> 8) & 0xff;
97 buffer_append(&buffer, buf, 4);
100 * Store the private key (n and e will not be stored because they
101 * will be stored in plain text, and storing them also in encrypted
102 * format would just give known plaintext).
104 buffer_put_bignum(&buffer, key->rsa->d);
105 buffer_put_bignum(&buffer, key->rsa->iqmp);
106 buffer_put_bignum(&buffer, key->rsa->q); /* reverse from SSL p */
107 buffer_put_bignum(&buffer, key->rsa->p); /* reverse from SSL q */
109 /* Pad the part to be encrypted until its size is a multiple of 8. */
110 while (buffer_len(&buffer) % 8 != 0)
111 buffer_put_char(&buffer, 0);
113 /* This buffer will be used to contain the data in the file. */
114 buffer_init(&encrypted);
116 /* First store keyfile id string. */
117 for (i = 0; authfile_id_string[i]; i++)
118 buffer_put_char(&encrypted, authfile_id_string[i]);
119 buffer_put_char(&encrypted, 0);
121 /* Store cipher type. */
122 buffer_put_char(&encrypted, cipher->number);
123 buffer_put_int(&encrypted, 0); /* For future extension */
125 /* Store public key. This will be in plain text. */
126 buffer_put_int(&encrypted, BN_num_bits(key->rsa->n));
127 buffer_put_bignum(&encrypted, key->rsa->n);
128 buffer_put_bignum(&encrypted, key->rsa->e);
129 buffer_put_string(&encrypted, comment, strlen(comment));
131 /* Allocate space for the private part of the key in the buffer. */
132 buffer_append_space(&encrypted, &cp, buffer_len(&buffer));
134 cipher_set_key_string(&ciphercontext, cipher, passphrase);
135 cipher_encrypt(&ciphercontext, (u_char *) cp,
136 (u_char *) buffer_ptr(&buffer), buffer_len(&buffer));
137 memset(&ciphercontext, 0, sizeof(ciphercontext));
139 /* Destroy temporary data. */
140 memset(buf, 0, sizeof(buf));
141 buffer_free(&buffer);
143 fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0600);
145 error("open %s failed: %s.", filename, strerror(errno));
148 if (write(fd, buffer_ptr(&encrypted), buffer_len(&encrypted)) !=
149 buffer_len(&encrypted)) {
150 error("write to key file %s failed: %s", filename,
152 buffer_free(&encrypted);
158 buffer_free(&encrypted);
162 /* save SSH v2 key in OpenSSL PEM format */
164 key_save_private_pem(Key *key, const char *filename, const char *_passphrase,
170 int len = strlen(_passphrase);
171 char *passphrase = (len > 0) ? (char *)_passphrase : NULL;
172 EVP_CIPHER *cipher = (len > 0) ? EVP_des_ede3_cbc() : NULL;
174 if (len > 0 && len <= 4) {
175 error("passphrase too short: have %d bytes, need > 4", len);
178 fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0600);
180 error("open %s failed: %s.", filename, strerror(errno));
183 fp = fdopen(fd, "w");
185 error("fdopen %s failed: %s.", filename, strerror(errno));
191 success = PEM_write_DSAPrivateKey(fp, key->dsa,
192 cipher, passphrase, len, NULL, NULL);
195 success = PEM_write_RSAPrivateKey(fp, key->rsa,
196 cipher, passphrase, len, NULL, NULL);
204 key_save_private(Key *key, const char *filename, const char *passphrase,
209 return key_save_private_rsa1(key, filename, passphrase,
214 return key_save_private_pem(key, filename, passphrase,
220 error("key_save_private: cannot save key type %d", key->type);
225 * Loads the public part of the ssh v1 key file. Returns NULL if an error was
226 * encountered (the file does not exist or is not readable), and the key
231 key_load_public_rsa1(int fd, const char *filename, char **commentp)
239 len = lseek(fd, (off_t) 0, SEEK_END);
240 lseek(fd, (off_t) 0, SEEK_SET);
242 buffer_init(&buffer);
243 buffer_append_space(&buffer, &cp, len);
245 if (read(fd, cp, (size_t) len) != (size_t) len) {
246 debug("Read from key file %.200s failed: %.100s", filename,
248 buffer_free(&buffer);
252 /* Check that it is at least big enough to contain the ID string. */
253 if (len < sizeof(authfile_id_string)) {
254 debug3("No RSA1 key file %.200s.", filename);
255 buffer_free(&buffer);
259 * Make sure it begins with the id string. Consume the id string
262 for (i = 0; i < sizeof(authfile_id_string); i++)
263 if (buffer_get_char(&buffer) != authfile_id_string[i]) {
264 debug3("No RSA1 key file %.200s.", filename);
265 buffer_free(&buffer);
268 /* Skip cipher type and reserved data. */
269 (void) buffer_get_char(&buffer); /* cipher type */
270 (void) buffer_get_int(&buffer); /* reserved */
272 /* Read the public key from the buffer. */
273 buffer_get_int(&buffer);
274 pub = key_new(KEY_RSA1);
275 buffer_get_bignum(&buffer, pub->rsa->n);
276 buffer_get_bignum(&buffer, pub->rsa->e);
278 *commentp = buffer_get_string(&buffer, NULL);
279 /* The encrypted private part is not parsed by this function. */
281 buffer_free(&buffer);
285 /* load public key from private-key file, works only for SSH v1 */
287 key_load_public_type(int type, const char *filename, char **commentp)
292 if (type == KEY_RSA1) {
293 fd = open(filename, O_RDONLY);
296 pub = key_load_public_rsa1(fd, filename, commentp);
304 * Loads the private key from the file. Returns 0 if an error is encountered
305 * (file does not exist or is not readable, or passphrase is bad). This
306 * initializes the private key.
307 * Assumes we are called under uid of the owner of the file.
311 key_load_private_rsa1(int fd, const char *filename, const char *passphrase,
314 int i, check1, check2, cipher_type;
316 Buffer buffer, decrypted;
318 CipherContext ciphercontext;
324 len = lseek(fd, (off_t) 0, SEEK_END);
325 lseek(fd, (off_t) 0, SEEK_SET);
327 buffer_init(&buffer);
328 buffer_append_space(&buffer, &cp, len);
330 if (read(fd, cp, (size_t) len) != (size_t) len) {
331 debug("Read from key file %.200s failed: %.100s", filename,
333 buffer_free(&buffer);
338 /* Check that it is at least big enough to contain the ID string. */
339 if (len < sizeof(authfile_id_string)) {
340 debug3("No RSA1 key file %.200s.", filename);
341 buffer_free(&buffer);
346 * Make sure it begins with the id string. Consume the id string
349 for (i = 0; i < sizeof(authfile_id_string); i++)
350 if (buffer_get_char(&buffer) != authfile_id_string[i]) {
351 debug3("No RSA1 key file %.200s.", filename);
352 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);
363 prv = key_new_private(KEY_RSA1);
365 buffer_get_bignum(&buffer, prv->rsa->n);
366 buffer_get_bignum(&buffer, prv->rsa->e);
368 *commentp = 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.",
398 /* Bad passphrase. */
399 buffer_free(&decrypted);
402 /* Read the rest of the private key. */
403 buffer_get_bignum(&decrypted, prv->rsa->d);
404 buffer_get_bignum(&decrypted, prv->rsa->iqmp); /* u */
405 /* in SSL and SSH v1 p and q are exchanged */
406 buffer_get_bignum(&decrypted, prv->rsa->q); /* p */
407 buffer_get_bignum(&decrypted, prv->rsa->p); /* q */
409 /* calculate p-1 and q-1 */
413 BN_sub(aux, prv->rsa->q, BN_value_one());
414 BN_mod(prv->rsa->dmq1, prv->rsa->d, aux, ctx);
416 BN_sub(aux, prv->rsa->p, BN_value_one());
417 BN_mod(prv->rsa->dmp1, prv->rsa->d, aux, ctx);
422 buffer_free(&decrypted);
435 key_load_private_pem(int fd, int type, const char *passphrase,
441 char *name = "<no key>";
443 fp = fdopen(fd, "r");
445 error("fdopen failed: %s", strerror(errno));
449 pk = PEM_read_PrivateKey(fp, NULL, NULL, (char *)passphrase);
451 debug("PEM_read_PrivateKey failed");
452 (void)ERR_get_error();
453 } else if (pk->type == EVP_PKEY_RSA &&
454 (type == KEY_UNSPEC||type==KEY_RSA)) {
455 prv = key_new(KEY_UNSPEC);
456 prv->rsa = EVP_PKEY_get1_RSA(pk);
458 name = "rsa w/o comment";
460 RSA_print_fp(stderr, prv->rsa, 8);
462 } else if (pk->type == EVP_PKEY_DSA &&
463 (type == KEY_UNSPEC||type==KEY_DSA)) {
464 prv = key_new(KEY_UNSPEC);
465 prv->dsa = EVP_PKEY_get1_DSA(pk);
467 name = "dsa w/o comment";
469 DSA_print_fp(stderr, prv->dsa, 8);
472 error("PEM_read_PrivateKey: mismatch or "
473 "unknown EVP_PKEY save_type %d", pk->save_type);
478 if (prv != NULL && commentp)
479 *commentp = xstrdup(name);
480 debug("read PEM private key done: type %s",
481 prv ? key_type(prv) : "<unknown>");
486 key_perm_ok(int fd, const char *filename)
490 /* check owner and modes */
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 error("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 error("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))