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.
40 #include <sys/types.h>
43 #include <openssl/err.h>
44 #include <openssl/evp.h>
45 #include <openssl/pem.h>
59 /* Version identification string for SSH v1 identity files. */
60 static const char authfile_id_string[] =
61 "SSH PRIVATE KEY FILE FORMAT 1.1\n";
64 * Saves the authentication (private) key in a file, encrypting it with
65 * passphrase. The identification of the file (lowest 64 bits of n) will
66 * precede the key to provide identification of the key without needing a
71 key_save_private_rsa1(Key *key, const char *filename, const char *passphrase,
74 Buffer buffer, encrypted;
76 int fd, i, cipher_num;
77 CipherContext ciphercontext;
82 * If the passphrase is empty, use SSH_CIPHER_NONE to ease converting
83 * to another cipher; otherwise use SSH_AUTHFILE_CIPHER.
85 cipher_num = (strcmp(passphrase, "") == 0) ?
86 SSH_CIPHER_NONE : SSH_AUTHFILE_CIPHER;
87 if ((cipher = cipher_by_number(cipher_num)) == NULL)
88 fatal("save_private_key_rsa: bad cipher");
90 /* This buffer is used to built the secret part of the private key. */
93 /* Put checkbytes for checking passphrase validity. */
96 buf[1] = (rnd >> 8) & 0xff;
99 buffer_append(&buffer, buf, 4);
102 * Store the private key (n and e will not be stored because they
103 * will be stored in plain text, and storing them also in encrypted
104 * format would just give known plaintext).
106 buffer_put_bignum(&buffer, key->rsa->d);
107 buffer_put_bignum(&buffer, key->rsa->iqmp);
108 buffer_put_bignum(&buffer, key->rsa->q); /* reverse from SSL p */
109 buffer_put_bignum(&buffer, key->rsa->p); /* reverse from SSL q */
111 /* Pad the part to be encrypted until its size is a multiple of 8. */
112 while (buffer_len(&buffer) % 8 != 0)
113 buffer_put_char(&buffer, 0);
115 /* This buffer will be used to contain the data in the file. */
116 buffer_init(&encrypted);
118 /* First store keyfile id string. */
119 for (i = 0; authfile_id_string[i]; i++)
120 buffer_put_char(&encrypted, authfile_id_string[i]);
121 buffer_put_char(&encrypted, 0);
123 /* Store cipher type. */
124 buffer_put_char(&encrypted, cipher_num);
125 buffer_put_int(&encrypted, 0); /* For future extension */
127 /* Store public key. This will be in plain text. */
128 buffer_put_int(&encrypted, BN_num_bits(key->rsa->n));
129 buffer_put_bignum(&encrypted, key->rsa->n);
130 buffer_put_bignum(&encrypted, key->rsa->e);
131 buffer_put_cstring(&encrypted, comment);
133 /* Allocate space for the private part of the key in the buffer. */
134 cp = buffer_append_space(&encrypted, buffer_len(&buffer));
136 cipher_set_key_string(&ciphercontext, cipher, passphrase,
138 cipher_crypt(&ciphercontext, cp,
139 buffer_ptr(&buffer), buffer_len(&buffer));
140 cipher_cleanup(&ciphercontext);
141 memset(&ciphercontext, 0, sizeof(ciphercontext));
143 /* Destroy temporary data. */
144 memset(buf, 0, sizeof(buf));
145 buffer_free(&buffer);
147 fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0600);
149 error("open %s failed: %s.", filename, strerror(errno));
150 buffer_free(&encrypted);
153 if (atomicio(vwrite, fd, buffer_ptr(&encrypted),
154 buffer_len(&encrypted)) != buffer_len(&encrypted)) {
155 error("write to key file %s failed: %s", filename,
157 buffer_free(&encrypted);
163 buffer_free(&encrypted);
167 /* save SSH v2 key in OpenSSL PEM format */
169 key_save_private_pem(Key *key, const char *filename, const char *_passphrase,
175 int len = strlen(_passphrase);
176 u_char *passphrase = (len > 0) ? (u_char *)_passphrase : NULL;
177 const EVP_CIPHER *cipher = (len > 0) ? EVP_des_ede3_cbc() : NULL;
179 if (len > 0 && len <= 4) {
180 error("passphrase too short: have %d bytes, need > 4", len);
183 fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0600);
185 error("open %s failed: %s.", filename, strerror(errno));
188 fp = fdopen(fd, "w");
190 error("fdopen %s failed: %s.", filename, strerror(errno));
196 success = PEM_write_DSAPrivateKey(fp, key->dsa,
197 cipher, passphrase, len, NULL, NULL);
200 success = PEM_write_RSAPrivateKey(fp, key->rsa,
201 cipher, passphrase, len, NULL, NULL);
209 key_save_private(Key *key, const char *filename, const char *passphrase,
214 return key_save_private_rsa1(key, filename, passphrase,
219 return key_save_private_pem(key, filename, passphrase,
225 error("key_save_private: cannot save key type %d", key->type);
230 * Loads the public part of the ssh v1 key file. Returns NULL if an error was
231 * encountered (the file does not exist or is not readable), and the key
236 key_load_public_rsa1(int fd, const char *filename, char **commentp)
245 if (fstat(fd, &st) < 0) {
246 error("fstat for key file %.200s failed: %.100s",
247 filename, strerror(errno));
250 if (st.st_size > 1*1024*1024) {
251 error("key file %.200s too large", filename);
254 len = (size_t)st.st_size; /* truncated */
256 buffer_init(&buffer);
257 cp = buffer_append_space(&buffer, len);
259 if (atomicio(read, fd, cp, len) != len) {
260 debug("Read from key file %.200s failed: %.100s", filename,
262 buffer_free(&buffer);
266 /* Check that it is at least big enough to contain the ID string. */
267 if (len < sizeof(authfile_id_string)) {
268 debug3("Not a RSA1 key file %.200s.", filename);
269 buffer_free(&buffer);
273 * Make sure it begins with the id string. Consume the id string
276 for (i = 0; i < sizeof(authfile_id_string); i++)
277 if (buffer_get_char(&buffer) != authfile_id_string[i]) {
278 debug3("Not a RSA1 key file %.200s.", filename);
279 buffer_free(&buffer);
282 /* Skip cipher type and reserved data. */
283 (void) buffer_get_char(&buffer); /* cipher type */
284 (void) buffer_get_int(&buffer); /* reserved */
286 /* Read the public key from the buffer. */
287 (void) buffer_get_int(&buffer);
288 pub = key_new(KEY_RSA1);
289 buffer_get_bignum(&buffer, pub->rsa->n);
290 buffer_get_bignum(&buffer, pub->rsa->e);
292 *commentp = buffer_get_string(&buffer, NULL);
293 /* The encrypted private part is not parsed by this function. */
295 buffer_free(&buffer);
299 /* load public key from private-key file, works only for SSH v1 */
301 key_load_public_type(int type, const char *filename, char **commentp)
306 if (type == KEY_RSA1) {
307 fd = open(filename, O_RDONLY);
310 pub = key_load_public_rsa1(fd, filename, commentp);
318 * Loads the private key from the file. Returns 0 if an error is encountered
319 * (file does not exist or is not readable, or passphrase is bad). This
320 * initializes the private key.
321 * Assumes we are called under uid of the owner of the file.
325 key_load_private_rsa1(int fd, const char *filename, const char *passphrase,
329 int check1, check2, cipher_type;
331 Buffer buffer, decrypted;
333 CipherContext ciphercontext;
338 if (fstat(fd, &st) < 0) {
339 error("fstat for key file %.200s failed: %.100s",
340 filename, strerror(errno));
344 if (st.st_size > 1*1024*1024) {
345 error("key file %.200s too large", filename);
349 len = (size_t)st.st_size; /* truncated */
351 buffer_init(&buffer);
352 cp = buffer_append_space(&buffer, len);
354 if (atomicio(read, fd, cp, len) != len) {
355 debug("Read from key file %.200s failed: %.100s", filename,
357 buffer_free(&buffer);
362 /* Check that it is at least big enough to contain the ID string. */
363 if (len < sizeof(authfile_id_string)) {
364 debug3("Not a RSA1 key file %.200s.", filename);
365 buffer_free(&buffer);
370 * Make sure it begins with the id string. Consume the id string
373 for (i = 0; i < sizeof(authfile_id_string); i++)
374 if (buffer_get_char(&buffer) != authfile_id_string[i]) {
375 debug3("Not a RSA1 key file %.200s.", filename);
376 buffer_free(&buffer);
381 /* Read cipher type. */
382 cipher_type = buffer_get_char(&buffer);
383 (void) buffer_get_int(&buffer); /* Reserved data. */
385 /* Read the public key from the buffer. */
386 (void) buffer_get_int(&buffer);
387 prv = key_new_private(KEY_RSA1);
389 buffer_get_bignum(&buffer, prv->rsa->n);
390 buffer_get_bignum(&buffer, prv->rsa->e);
392 *commentp = buffer_get_string(&buffer, NULL);
394 xfree(buffer_get_string(&buffer, NULL));
396 /* Check that it is a supported cipher. */
397 cipher = cipher_by_number(cipher_type);
398 if (cipher == NULL) {
399 debug("Unsupported cipher %d used in key file %.200s.",
400 cipher_type, filename);
401 buffer_free(&buffer);
404 /* Initialize space for decrypted data. */
405 buffer_init(&decrypted);
406 cp = buffer_append_space(&decrypted, buffer_len(&buffer));
408 /* Rest of the buffer is encrypted. Decrypt it using the passphrase. */
409 cipher_set_key_string(&ciphercontext, cipher, passphrase,
411 cipher_crypt(&ciphercontext, cp,
412 buffer_ptr(&buffer), buffer_len(&buffer));
413 cipher_cleanup(&ciphercontext);
414 memset(&ciphercontext, 0, sizeof(ciphercontext));
415 buffer_free(&buffer);
417 check1 = buffer_get_char(&decrypted);
418 check2 = buffer_get_char(&decrypted);
419 if (check1 != buffer_get_char(&decrypted) ||
420 check2 != buffer_get_char(&decrypted)) {
421 if (strcmp(passphrase, "") != 0)
422 debug("Bad passphrase supplied for key file %.200s.",
424 /* Bad passphrase. */
425 buffer_free(&decrypted);
428 /* Read the rest of the private key. */
429 buffer_get_bignum(&decrypted, prv->rsa->d);
430 buffer_get_bignum(&decrypted, prv->rsa->iqmp); /* u */
431 /* in SSL and SSH v1 p and q are exchanged */
432 buffer_get_bignum(&decrypted, prv->rsa->q); /* p */
433 buffer_get_bignum(&decrypted, prv->rsa->p); /* q */
435 /* calculate p-1 and q-1 */
436 rsa_generate_additional_parameters(prv->rsa);
438 buffer_free(&decrypted);
440 /* enable blinding */
441 if (RSA_blinding_on(prv->rsa, NULL) != 1) {
442 error("key_load_private_rsa1: RSA_blinding_on failed");
457 key_load_private_pem(int fd, int type, const char *passphrase,
463 char *name = "<no key>";
465 fp = fdopen(fd, "r");
467 error("fdopen failed: %s", strerror(errno));
471 pk = PEM_read_PrivateKey(fp, NULL, NULL, (char *)passphrase);
473 debug("PEM_read_PrivateKey failed");
474 (void)ERR_get_error();
475 } else if (pk->type == EVP_PKEY_RSA &&
476 (type == KEY_UNSPEC||type==KEY_RSA)) {
477 prv = key_new(KEY_UNSPEC);
478 prv->rsa = EVP_PKEY_get1_RSA(pk);
480 name = "rsa w/o comment";
482 RSA_print_fp(stderr, prv->rsa, 8);
484 if (RSA_blinding_on(prv->rsa, NULL) != 1) {
485 error("key_load_private_pem: RSA_blinding_on failed");
489 } else if (pk->type == EVP_PKEY_DSA &&
490 (type == KEY_UNSPEC||type==KEY_DSA)) {
491 prv = key_new(KEY_UNSPEC);
492 prv->dsa = EVP_PKEY_get1_DSA(pk);
494 name = "dsa w/o comment";
496 DSA_print_fp(stderr, prv->dsa, 8);
499 error("PEM_read_PrivateKey: mismatch or "
500 "unknown EVP_PKEY save_type %d", pk->save_type);
505 if (prv != NULL && commentp)
506 *commentp = xstrdup(name);
507 debug("read PEM private key done: type %s",
508 prv ? key_type(prv) : "<unknown>");
513 key_perm_ok(int fd, const char *filename)
517 if (fstat(fd, &st) < 0)
520 * if a key owned by the user is accessed, then we check the
521 * permissions of the file. if the key owned by a different user,
522 * then we don't care.
525 if (check_ntsec(filename))
527 if ((st.st_uid == getuid()) && (st.st_mode & 077) != 0) {
528 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
529 error("@ WARNING: UNPROTECTED PRIVATE KEY FILE! @");
530 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
531 error("Permissions 0%3.3o for '%s' are too open.",
532 (u_int)st.st_mode & 0777, filename);
533 error("It is recommended that your private key files are NOT accessible by others.");
534 error("This private key will be ignored.");
541 key_load_private_type(int type, const char *filename, const char *passphrase,
546 fd = open(filename, O_RDONLY);
549 if (!key_perm_ok(fd, filename)) {
550 error("bad permissions: ignore key: %s", filename);
556 return key_load_private_rsa1(fd, filename, passphrase,
563 return key_load_private_pem(fd, type, passphrase, commentp);
574 key_load_private(const char *filename, const char *passphrase,
580 fd = open(filename, O_RDONLY);
583 if (!key_perm_ok(fd, filename)) {
584 error("bad permissions: ignore key: %s", filename);
588 pub = key_load_public_rsa1(fd, filename, commentp);
589 lseek(fd, (off_t) 0, SEEK_SET); /* rewind */
592 prv = key_load_private_pem(fd, KEY_UNSPEC, passphrase, NULL);
593 /* use the filename as a comment for PEM */
595 *commentp = xstrdup(filename);
597 /* it's a SSH v1 key if the public key part is readable */
600 prv = key_load_private_rsa1(fd, filename, passphrase, NULL);
606 key_try_load_public(Key *k, const char *filename, char **commentp)
609 char line[SSH_MAX_PUBKEY_BYTES];
613 f = fopen(filename, "r");
615 while (read_keyfile_line(f, filename, line, sizeof(line),
624 /* Skip leading whitespace. */
625 for (; *cp && (*cp == ' ' || *cp == '\t'); cp++)
628 if (key_read(k, &cp) == 1) {
630 *commentp=xstrdup(filename);
641 /* load public key from ssh v1 private or any pubkey file */
643 key_load_public(const char *filename, char **commentp)
646 char file[MAXPATHLEN];
648 /* try rsa1 private key */
649 pub = key_load_public_type(KEY_RSA1, filename, commentp);
653 /* try rsa1 public key */
654 pub = key_new(KEY_RSA1);
655 if (key_try_load_public(pub, filename, commentp) == 1)
659 /* try ssh2 public key */
660 pub = key_new(KEY_UNSPEC);
661 if (key_try_load_public(pub, filename, commentp) == 1)
663 if ((strlcpy(file, filename, sizeof file) < sizeof(file)) &&
664 (strlcat(file, ".pub", sizeof file) < sizeof(file)) &&
665 (key_try_load_public(pub, file, commentp) == 1))