1 /* $OpenBSD: authfile.c,v 1.72 2006/07/26 02:35:17 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>
43 #include <sys/param.h>
45 #include <openssl/err.h>
46 #include <openssl/evp.h>
47 #include <openssl/pem.h>
66 /* Version identification string for SSH v1 identity files. */
67 static const char authfile_id_string[] =
68 "SSH PRIVATE KEY FILE FORMAT 1.1\n";
71 * Saves the authentication (private) key in a file, encrypting it with
72 * passphrase. The identification of the file (lowest 64 bits of n) will
73 * precede the key to provide identification of the key without needing a
78 key_save_private_rsa1(Key *key, const char *filename, const char *passphrase,
81 Buffer buffer, encrypted;
83 int fd, i, cipher_num;
84 CipherContext ciphercontext;
89 * If the passphrase is empty, use SSH_CIPHER_NONE to ease converting
90 * to another cipher; otherwise use SSH_AUTHFILE_CIPHER.
92 cipher_num = (strcmp(passphrase, "") == 0) ?
93 SSH_CIPHER_NONE : SSH_AUTHFILE_CIPHER;
94 if ((cipher = cipher_by_number(cipher_num)) == NULL)
95 fatal("save_private_key_rsa: bad cipher");
97 /* This buffer is used to built the secret part of the private key. */
100 /* Put checkbytes for checking passphrase validity. */
103 buf[1] = (rnd >> 8) & 0xff;
106 buffer_append(&buffer, buf, 4);
109 * Store the private key (n and e will not be stored because they
110 * will be stored in plain text, and storing them also in encrypted
111 * format would just give known plaintext).
113 buffer_put_bignum(&buffer, key->rsa->d);
114 buffer_put_bignum(&buffer, key->rsa->iqmp);
115 buffer_put_bignum(&buffer, key->rsa->q); /* reverse from SSL p */
116 buffer_put_bignum(&buffer, key->rsa->p); /* reverse from SSL q */
118 /* Pad the part to be encrypted until its size is a multiple of 8. */
119 while (buffer_len(&buffer) % 8 != 0)
120 buffer_put_char(&buffer, 0);
122 /* This buffer will be used to contain the data in the file. */
123 buffer_init(&encrypted);
125 /* First store keyfile id string. */
126 for (i = 0; authfile_id_string[i]; i++)
127 buffer_put_char(&encrypted, authfile_id_string[i]);
128 buffer_put_char(&encrypted, 0);
130 /* Store cipher type. */
131 buffer_put_char(&encrypted, cipher_num);
132 buffer_put_int(&encrypted, 0); /* For future extension */
134 /* Store public key. This will be in plain text. */
135 buffer_put_int(&encrypted, BN_num_bits(key->rsa->n));
136 buffer_put_bignum(&encrypted, key->rsa->n);
137 buffer_put_bignum(&encrypted, key->rsa->e);
138 buffer_put_cstring(&encrypted, comment);
140 /* Allocate space for the private part of the key in the buffer. */
141 cp = buffer_append_space(&encrypted, buffer_len(&buffer));
143 cipher_set_key_string(&ciphercontext, cipher, passphrase,
145 cipher_crypt(&ciphercontext, cp,
146 buffer_ptr(&buffer), buffer_len(&buffer));
147 cipher_cleanup(&ciphercontext);
148 memset(&ciphercontext, 0, sizeof(ciphercontext));
150 /* Destroy temporary data. */
151 memset(buf, 0, sizeof(buf));
152 buffer_free(&buffer);
154 fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0600);
156 error("open %s failed: %s.", filename, strerror(errno));
157 buffer_free(&encrypted);
160 if (atomicio(vwrite, fd, buffer_ptr(&encrypted),
161 buffer_len(&encrypted)) != buffer_len(&encrypted)) {
162 error("write to key file %s failed: %s", filename,
164 buffer_free(&encrypted);
170 buffer_free(&encrypted);
174 /* save SSH v2 key in OpenSSL PEM format */
176 key_save_private_pem(Key *key, const char *filename, const char *_passphrase,
182 int len = strlen(_passphrase);
183 u_char *passphrase = (len > 0) ? (u_char *)_passphrase : NULL;
184 const EVP_CIPHER *cipher = (len > 0) ? EVP_des_ede3_cbc() : NULL;
186 if (len > 0 && len <= 4) {
187 error("passphrase too short: have %d bytes, need > 4", len);
190 fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0600);
192 error("open %s failed: %s.", filename, strerror(errno));
195 fp = fdopen(fd, "w");
197 error("fdopen %s failed: %s.", filename, strerror(errno));
203 success = PEM_write_DSAPrivateKey(fp, key->dsa,
204 cipher, passphrase, len, NULL, NULL);
207 success = PEM_write_RSAPrivateKey(fp, key->rsa,
208 cipher, passphrase, len, NULL, NULL);
216 key_save_private(Key *key, const char *filename, const char *passphrase,
221 return key_save_private_rsa1(key, filename, passphrase,
225 return key_save_private_pem(key, filename, passphrase,
230 error("key_save_private: cannot save key type %d", key->type);
235 * Loads the public part of the ssh v1 key file. Returns NULL if an error was
236 * encountered (the file does not exist or is not readable), and the key
241 key_load_public_rsa1(int fd, const char *filename, char **commentp)
250 if (fstat(fd, &st) < 0) {
251 error("fstat for key file %.200s failed: %.100s",
252 filename, strerror(errno));
255 if (st.st_size > 1*1024*1024) {
256 error("key file %.200s too large", filename);
259 len = (size_t)st.st_size; /* truncated */
261 buffer_init(&buffer);
262 cp = buffer_append_space(&buffer, len);
264 if (atomicio(read, fd, cp, len) != len) {
265 debug("Read from key file %.200s failed: %.100s", filename,
267 buffer_free(&buffer);
271 /* Check that it is at least big enough to contain the ID string. */
272 if (len < sizeof(authfile_id_string)) {
273 debug3("Not a RSA1 key file %.200s.", filename);
274 buffer_free(&buffer);
278 * Make sure it begins with the id string. Consume the id string
281 for (i = 0; i < sizeof(authfile_id_string); i++)
282 if (buffer_get_char(&buffer) != authfile_id_string[i]) {
283 debug3("Not a RSA1 key file %.200s.", filename);
284 buffer_free(&buffer);
287 /* Skip cipher type and reserved data. */
288 (void) buffer_get_char(&buffer); /* cipher type */
289 (void) buffer_get_int(&buffer); /* reserved */
291 /* Read the public key from the buffer. */
292 (void) buffer_get_int(&buffer);
293 pub = key_new(KEY_RSA1);
294 buffer_get_bignum(&buffer, pub->rsa->n);
295 buffer_get_bignum(&buffer, pub->rsa->e);
297 *commentp = buffer_get_string(&buffer, NULL);
298 /* The encrypted private part is not parsed by this function. */
300 buffer_free(&buffer);
304 /* load public key from private-key file, works only for SSH v1 */
306 key_load_public_type(int type, const char *filename, char **commentp)
311 if (type == KEY_RSA1) {
312 fd = open(filename, O_RDONLY);
315 pub = key_load_public_rsa1(fd, filename, commentp);
323 * Loads the private key from the file. Returns 0 if an error is encountered
324 * (file does not exist or is not readable, or passphrase is bad). This
325 * initializes the private key.
326 * Assumes we are called under uid of the owner of the file.
330 key_load_private_rsa1(int fd, const char *filename, const char *passphrase,
334 int check1, check2, cipher_type;
336 Buffer buffer, decrypted;
338 CipherContext ciphercontext;
343 if (fstat(fd, &st) < 0) {
344 error("fstat for key file %.200s failed: %.100s",
345 filename, strerror(errno));
349 if (st.st_size > 1*1024*1024) {
350 error("key file %.200s too large", filename);
354 len = (size_t)st.st_size; /* truncated */
356 buffer_init(&buffer);
357 cp = buffer_append_space(&buffer, len);
359 if (atomicio(read, fd, cp, len) != len) {
360 debug("Read from key file %.200s failed: %.100s", filename,
362 buffer_free(&buffer);
367 /* Check that it is at least big enough to contain the ID string. */
368 if (len < sizeof(authfile_id_string)) {
369 debug3("Not a RSA1 key file %.200s.", filename);
370 buffer_free(&buffer);
375 * Make sure it begins with the id string. Consume the id string
378 for (i = 0; i < sizeof(authfile_id_string); i++)
379 if (buffer_get_char(&buffer) != authfile_id_string[i]) {
380 debug3("Not a RSA1 key file %.200s.", filename);
381 buffer_free(&buffer);
386 /* Read cipher type. */
387 cipher_type = buffer_get_char(&buffer);
388 (void) buffer_get_int(&buffer); /* Reserved data. */
390 /* Read the public key from the buffer. */
391 (void) buffer_get_int(&buffer);
392 prv = key_new_private(KEY_RSA1);
394 buffer_get_bignum(&buffer, prv->rsa->n);
395 buffer_get_bignum(&buffer, prv->rsa->e);
397 *commentp = buffer_get_string(&buffer, NULL);
399 xfree(buffer_get_string(&buffer, NULL));
401 /* Check that it is a supported cipher. */
402 cipher = cipher_by_number(cipher_type);
403 if (cipher == NULL) {
404 debug("Unsupported cipher %d used in key file %.200s.",
405 cipher_type, filename);
406 buffer_free(&buffer);
409 /* Initialize space for decrypted data. */
410 buffer_init(&decrypted);
411 cp = buffer_append_space(&decrypted, buffer_len(&buffer));
413 /* Rest of the buffer is encrypted. Decrypt it using the passphrase. */
414 cipher_set_key_string(&ciphercontext, cipher, passphrase,
416 cipher_crypt(&ciphercontext, cp,
417 buffer_ptr(&buffer), buffer_len(&buffer));
418 cipher_cleanup(&ciphercontext);
419 memset(&ciphercontext, 0, sizeof(ciphercontext));
420 buffer_free(&buffer);
422 check1 = buffer_get_char(&decrypted);
423 check2 = buffer_get_char(&decrypted);
424 if (check1 != buffer_get_char(&decrypted) ||
425 check2 != buffer_get_char(&decrypted)) {
426 if (strcmp(passphrase, "") != 0)
427 debug("Bad passphrase supplied for key file %.200s.",
429 /* Bad passphrase. */
430 buffer_free(&decrypted);
433 /* Read the rest of the private key. */
434 buffer_get_bignum(&decrypted, prv->rsa->d);
435 buffer_get_bignum(&decrypted, prv->rsa->iqmp); /* u */
436 /* in SSL and SSH v1 p and q are exchanged */
437 buffer_get_bignum(&decrypted, prv->rsa->q); /* p */
438 buffer_get_bignum(&decrypted, prv->rsa->p); /* q */
440 /* calculate p-1 and q-1 */
441 rsa_generate_additional_parameters(prv->rsa);
443 buffer_free(&decrypted);
445 /* enable blinding */
446 if (RSA_blinding_on(prv->rsa, NULL) != 1) {
447 error("key_load_private_rsa1: RSA_blinding_on failed");
462 key_load_private_pem(int fd, int type, const char *passphrase,
468 char *name = "<no key>";
470 fp = fdopen(fd, "r");
472 error("fdopen failed: %s", strerror(errno));
476 pk = PEM_read_PrivateKey(fp, NULL, NULL, (char *)passphrase);
478 debug("PEM_read_PrivateKey failed");
479 (void)ERR_get_error();
480 } else if (pk->type == EVP_PKEY_RSA &&
481 (type == KEY_UNSPEC||type==KEY_RSA)) {
482 prv = key_new(KEY_UNSPEC);
483 prv->rsa = EVP_PKEY_get1_RSA(pk);
485 name = "rsa w/o comment";
487 RSA_print_fp(stderr, prv->rsa, 8);
489 if (RSA_blinding_on(prv->rsa, NULL) != 1) {
490 error("key_load_private_pem: RSA_blinding_on failed");
494 } else if (pk->type == EVP_PKEY_DSA &&
495 (type == KEY_UNSPEC||type==KEY_DSA)) {
496 prv = key_new(KEY_UNSPEC);
497 prv->dsa = EVP_PKEY_get1_DSA(pk);
499 name = "dsa w/o comment";
501 DSA_print_fp(stderr, prv->dsa, 8);
504 error("PEM_read_PrivateKey: mismatch or "
505 "unknown EVP_PKEY save_type %d", pk->save_type);
510 if (prv != NULL && commentp)
511 *commentp = xstrdup(name);
512 debug("read PEM private key done: type %s",
513 prv ? key_type(prv) : "<unknown>");
518 key_perm_ok(int fd, const char *filename)
522 if (fstat(fd, &st) < 0)
525 * if a key owned by the user is accessed, then we check the
526 * permissions of the file. if the key owned by a different user,
527 * then we don't care.
530 if (check_ntsec(filename))
532 if ((st.st_uid == getuid()) && (st.st_mode & 077) != 0) {
533 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
534 error("@ WARNING: UNPROTECTED PRIVATE KEY FILE! @");
535 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
536 error("Permissions 0%3.3o for '%s' are too open.",
537 (u_int)st.st_mode & 0777, filename);
538 error("It is recommended that your private key files are NOT accessible by others.");
539 error("This private key will be ignored.");
546 key_load_private_type(int type, const char *filename, const char *passphrase,
547 char **commentp, int *perm_ok)
551 fd = open(filename, O_RDONLY);
554 if (!key_perm_ok(fd, filename)) {
557 error("bad permissions: ignore key: %s", filename);
565 return key_load_private_rsa1(fd, filename, passphrase,
571 return key_load_private_pem(fd, type, passphrase, commentp);
581 key_load_private(const char *filename, const char *passphrase,
587 fd = open(filename, O_RDONLY);
590 if (!key_perm_ok(fd, filename)) {
591 error("bad permissions: ignore key: %s", filename);
595 pub = key_load_public_rsa1(fd, filename, commentp);
596 lseek(fd, (off_t) 0, SEEK_SET); /* rewind */
599 prv = key_load_private_pem(fd, KEY_UNSPEC, passphrase, NULL);
600 /* use the filename as a comment for PEM */
602 *commentp = xstrdup(filename);
604 /* it's a SSH v1 key if the public key part is readable */
607 prv = key_load_private_rsa1(fd, filename, passphrase, NULL);
613 key_try_load_public(Key *k, const char *filename, char **commentp)
616 char line[SSH_MAX_PUBKEY_BYTES];
620 f = fopen(filename, "r");
622 while (read_keyfile_line(f, filename, line, sizeof(line),
631 /* Skip leading whitespace. */
632 for (; *cp && (*cp == ' ' || *cp == '\t'); cp++)
635 if (key_read(k, &cp) == 1) {
637 *commentp=xstrdup(filename);
648 /* load public key from ssh v1 private or any pubkey file */
650 key_load_public(const char *filename, char **commentp)
653 char file[MAXPATHLEN];
655 /* try rsa1 private key */
656 pub = key_load_public_type(KEY_RSA1, filename, commentp);
660 /* try rsa1 public key */
661 pub = key_new(KEY_RSA1);
662 if (key_try_load_public(pub, filename, commentp) == 1)
666 /* try ssh2 public key */
667 pub = key_new(KEY_UNSPEC);
668 if (key_try_load_public(pub, filename, commentp) == 1)
670 if ((strlcpy(file, filename, sizeof file) < sizeof(file)) &&
671 (strlcat(file, ".pub", sizeof file) < sizeof(file)) &&
672 (key_try_load_public(pub, file, commentp) == 1))