1 /* $OpenBSD: authfile.c,v 1.80 2010/03/04 10:36:03 djm 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>
46 #include <openssl/err.h>
47 #include <openssl/evp.h>
48 #include <openssl/pem.h>
50 /* compatibility with old or broken OpenSSL versions */
51 #include "openbsd-compat/openssl-compat.h"
72 /* Version identification string for SSH v1 identity files. */
73 static const char authfile_id_string[] =
74 "SSH PRIVATE KEY FILE FORMAT 1.1\n";
77 * Saves the authentication (private) key in a file, encrypting it with
78 * passphrase. The identification of the file (lowest 64 bits of n) will
79 * precede the key to provide identification of the key without needing a
84 key_save_private_rsa1(Key *key, const char *filename, const char *passphrase,
87 Buffer buffer, encrypted;
89 int fd, i, cipher_num;
90 CipherContext ciphercontext;
95 * If the passphrase is empty, use SSH_CIPHER_NONE to ease converting
96 * to another cipher; otherwise use SSH_AUTHFILE_CIPHER.
98 cipher_num = (strcmp(passphrase, "") == 0) ?
99 SSH_CIPHER_NONE : SSH_AUTHFILE_CIPHER;
100 if ((cipher = cipher_by_number(cipher_num)) == NULL)
101 fatal("save_private_key_rsa: bad cipher");
103 /* This buffer is used to built the secret part of the private key. */
104 buffer_init(&buffer);
106 /* Put checkbytes for checking passphrase validity. */
109 buf[1] = (rnd >> 8) & 0xff;
112 buffer_append(&buffer, buf, 4);
115 * Store the private key (n and e will not be stored because they
116 * will be stored in plain text, and storing them also in encrypted
117 * format would just give known plaintext).
119 buffer_put_bignum(&buffer, key->rsa->d);
120 buffer_put_bignum(&buffer, key->rsa->iqmp);
121 buffer_put_bignum(&buffer, key->rsa->q); /* reverse from SSL p */
122 buffer_put_bignum(&buffer, key->rsa->p); /* reverse from SSL q */
124 /* Pad the part to be encrypted until its size is a multiple of 8. */
125 while (buffer_len(&buffer) % 8 != 0)
126 buffer_put_char(&buffer, 0);
128 /* This buffer will be used to contain the data in the file. */
129 buffer_init(&encrypted);
131 /* First store keyfile id string. */
132 for (i = 0; authfile_id_string[i]; i++)
133 buffer_put_char(&encrypted, authfile_id_string[i]);
134 buffer_put_char(&encrypted, 0);
136 /* Store cipher type. */
137 buffer_put_char(&encrypted, cipher_num);
138 buffer_put_int(&encrypted, 0); /* For future extension */
140 /* Store public key. This will be in plain text. */
141 buffer_put_int(&encrypted, BN_num_bits(key->rsa->n));
142 buffer_put_bignum(&encrypted, key->rsa->n);
143 buffer_put_bignum(&encrypted, key->rsa->e);
144 buffer_put_cstring(&encrypted, comment);
146 /* Allocate space for the private part of the key in the buffer. */
147 cp = buffer_append_space(&encrypted, buffer_len(&buffer));
149 cipher_set_key_string(&ciphercontext, cipher, passphrase,
151 cipher_crypt(&ciphercontext, cp,
152 buffer_ptr(&buffer), buffer_len(&buffer));
153 cipher_cleanup(&ciphercontext);
154 memset(&ciphercontext, 0, sizeof(ciphercontext));
156 /* Destroy temporary data. */
157 memset(buf, 0, sizeof(buf));
158 buffer_free(&buffer);
160 fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0600);
162 error("open %s failed: %s.", filename, strerror(errno));
163 buffer_free(&encrypted);
166 if (atomicio(vwrite, fd, buffer_ptr(&encrypted),
167 buffer_len(&encrypted)) != buffer_len(&encrypted)) {
168 error("write to key file %s failed: %s", filename,
170 buffer_free(&encrypted);
176 buffer_free(&encrypted);
180 /* save SSH v2 key in OpenSSL PEM format */
182 key_save_private_pem(Key *key, const char *filename, const char *_passphrase,
188 int len = strlen(_passphrase);
189 u_char *passphrase = (len > 0) ? (u_char *)_passphrase : NULL;
190 #if (OPENSSL_VERSION_NUMBER < 0x00907000L)
191 const EVP_CIPHER *cipher = (len > 0) ? EVP_des_ede3_cbc() : NULL;
193 const EVP_CIPHER *cipher = (len > 0) ? EVP_aes_128_cbc() : NULL;
196 if (len > 0 && len <= 4) {
197 error("passphrase too short: have %d bytes, need > 4", len);
200 fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0600);
202 error("open %s failed: %s.", filename, strerror(errno));
205 fp = fdopen(fd, "w");
207 error("fdopen %s failed: %s.", filename, strerror(errno));
213 success = PEM_write_DSAPrivateKey(fp, key->dsa,
214 cipher, passphrase, len, NULL, NULL);
217 success = PEM_write_RSAPrivateKey(fp, key->rsa,
218 cipher, passphrase, len, NULL, NULL);
226 key_save_private(Key *key, const char *filename, const char *passphrase,
231 return key_save_private_rsa1(key, filename, passphrase,
235 return key_save_private_pem(key, filename, passphrase,
240 error("key_save_private: cannot save key type %d", key->type);
245 * Loads the public part of the ssh v1 key file. Returns NULL if an error was
246 * encountered (the file does not exist or is not readable), and the key
251 key_load_public_rsa1(int fd, const char *filename, char **commentp)
260 if (fstat(fd, &st) < 0) {
261 error("fstat for key file %.200s failed: %.100s",
262 filename, strerror(errno));
265 if (st.st_size > 1*1024*1024) {
266 error("key file %.200s too large", filename);
269 len = (size_t)st.st_size; /* truncated */
271 buffer_init(&buffer);
272 cp = buffer_append_space(&buffer, len);
274 if (atomicio(read, fd, cp, len) != len) {
275 debug("Read from key file %.200s failed: %.100s", filename,
277 buffer_free(&buffer);
281 /* Check that it is at least big enough to contain the ID string. */
282 if (len < sizeof(authfile_id_string)) {
283 debug3("Not a RSA1 key file %.200s.", filename);
284 buffer_free(&buffer);
288 * Make sure it begins with the id string. Consume the id string
291 for (i = 0; i < sizeof(authfile_id_string); i++)
292 if (buffer_get_char(&buffer) != authfile_id_string[i]) {
293 debug3("Not a RSA1 key file %.200s.", filename);
294 buffer_free(&buffer);
297 /* Skip cipher type and reserved data. */
298 (void) buffer_get_char(&buffer); /* cipher type */
299 (void) buffer_get_int(&buffer); /* reserved */
301 /* Read the public key from the buffer. */
302 (void) buffer_get_int(&buffer);
303 pub = key_new(KEY_RSA1);
304 buffer_get_bignum(&buffer, pub->rsa->n);
305 buffer_get_bignum(&buffer, pub->rsa->e);
307 *commentp = buffer_get_string(&buffer, NULL);
308 /* The encrypted private part is not parsed by this function. */
310 buffer_free(&buffer);
314 /* load public key from private-key file, works only for SSH v1 */
316 key_load_public_type(int type, const char *filename, char **commentp)
321 if (type == KEY_RSA1) {
322 fd = open(filename, O_RDONLY);
325 pub = key_load_public_rsa1(fd, filename, commentp);
333 * Loads the private key from the file. Returns 0 if an error is encountered
334 * (file does not exist or is not readable, or passphrase is bad). This
335 * initializes the private key.
336 * Assumes we are called under uid of the owner of the file.
340 key_load_private_rsa1(int fd, const char *filename, const char *passphrase,
344 int check1, check2, cipher_type;
346 Buffer buffer, decrypted;
348 CipherContext ciphercontext;
353 if (fstat(fd, &st) < 0) {
354 error("fstat for key file %.200s failed: %.100s",
355 filename, strerror(errno));
359 if (st.st_size > 1*1024*1024) {
360 error("key file %.200s too large", filename);
364 len = (size_t)st.st_size; /* truncated */
366 buffer_init(&buffer);
367 cp = buffer_append_space(&buffer, len);
369 if (atomicio(read, fd, cp, len) != len) {
370 debug("Read from key file %.200s failed: %.100s", filename,
372 buffer_free(&buffer);
377 /* Check that it is at least big enough to contain the ID string. */
378 if (len < sizeof(authfile_id_string)) {
379 debug3("Not a RSA1 key file %.200s.", filename);
380 buffer_free(&buffer);
385 * Make sure it begins with the id string. Consume the id string
388 for (i = 0; i < sizeof(authfile_id_string); i++)
389 if (buffer_get_char(&buffer) != authfile_id_string[i]) {
390 debug3("Not a RSA1 key file %.200s.", filename);
391 buffer_free(&buffer);
396 /* Read cipher type. */
397 cipher_type = buffer_get_char(&buffer);
398 (void) buffer_get_int(&buffer); /* Reserved data. */
400 /* Read the public key from the buffer. */
401 (void) buffer_get_int(&buffer);
402 prv = key_new_private(KEY_RSA1);
404 buffer_get_bignum(&buffer, prv->rsa->n);
405 buffer_get_bignum(&buffer, prv->rsa->e);
407 *commentp = buffer_get_string(&buffer, NULL);
409 xfree(buffer_get_string(&buffer, NULL));
411 /* Check that it is a supported cipher. */
412 cipher = cipher_by_number(cipher_type);
413 if (cipher == NULL) {
414 debug("Unsupported cipher %d used in key file %.200s.",
415 cipher_type, filename);
416 buffer_free(&buffer);
419 /* Initialize space for decrypted data. */
420 buffer_init(&decrypted);
421 cp = buffer_append_space(&decrypted, buffer_len(&buffer));
423 /* Rest of the buffer is encrypted. Decrypt it using the passphrase. */
424 cipher_set_key_string(&ciphercontext, cipher, passphrase,
426 cipher_crypt(&ciphercontext, cp,
427 buffer_ptr(&buffer), buffer_len(&buffer));
428 cipher_cleanup(&ciphercontext);
429 memset(&ciphercontext, 0, sizeof(ciphercontext));
430 buffer_free(&buffer);
432 check1 = buffer_get_char(&decrypted);
433 check2 = buffer_get_char(&decrypted);
434 if (check1 != buffer_get_char(&decrypted) ||
435 check2 != buffer_get_char(&decrypted)) {
436 if (strcmp(passphrase, "") != 0)
437 debug("Bad passphrase supplied for key file %.200s.",
439 /* Bad passphrase. */
440 buffer_free(&decrypted);
443 /* Read the rest of the private key. */
444 buffer_get_bignum(&decrypted, prv->rsa->d);
445 buffer_get_bignum(&decrypted, prv->rsa->iqmp); /* u */
446 /* in SSL and SSH v1 p and q are exchanged */
447 buffer_get_bignum(&decrypted, prv->rsa->q); /* p */
448 buffer_get_bignum(&decrypted, prv->rsa->p); /* q */
450 /* calculate p-1 and q-1 */
451 rsa_generate_additional_parameters(prv->rsa);
453 buffer_free(&decrypted);
455 /* enable blinding */
456 if (RSA_blinding_on(prv->rsa, NULL) != 1) {
457 error("key_load_private_rsa1: RSA_blinding_on failed");
472 key_load_private_pem(int fd, int type, const char *passphrase,
478 char *name = "<no key>";
480 fp = fdopen(fd, "r");
482 error("fdopen failed: %s", strerror(errno));
486 pk = PEM_read_PrivateKey(fp, NULL, NULL, (char *)passphrase);
488 debug("PEM_read_PrivateKey failed");
489 (void)ERR_get_error();
490 } else if (pk->type == EVP_PKEY_RSA &&
491 (type == KEY_UNSPEC||type==KEY_RSA)) {
492 prv = key_new(KEY_UNSPEC);
493 prv->rsa = EVP_PKEY_get1_RSA(pk);
495 name = "rsa w/o comment";
497 RSA_print_fp(stderr, prv->rsa, 8);
499 if (RSA_blinding_on(prv->rsa, NULL) != 1) {
500 error("key_load_private_pem: RSA_blinding_on failed");
504 } else if (pk->type == EVP_PKEY_DSA &&
505 (type == KEY_UNSPEC||type==KEY_DSA)) {
506 prv = key_new(KEY_UNSPEC);
507 prv->dsa = EVP_PKEY_get1_DSA(pk);
509 name = "dsa w/o comment";
511 DSA_print_fp(stderr, prv->dsa, 8);
514 error("PEM_read_PrivateKey: mismatch or "
515 "unknown EVP_PKEY save_type %d", pk->save_type);
520 if (prv != NULL && commentp)
521 *commentp = xstrdup(name);
522 debug("read PEM private key done: type %s",
523 prv ? key_type(prv) : "<unknown>");
528 key_perm_ok(int fd, const char *filename)
532 if (fstat(fd, &st) < 0)
535 * if a key owned by the user is accessed, then we check the
536 * permissions of the file. if the key owned by a different user,
537 * then we don't care.
540 if (check_ntsec(filename))
542 if ((st.st_uid == getuid()) && (st.st_mode & 077) != 0) {
543 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
544 error("@ WARNING: UNPROTECTED PRIVATE KEY FILE! @");
545 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
546 error("Permissions 0%3.3o for '%s' are too open.",
547 (u_int)st.st_mode & 0777, filename);
548 error("It is recommended that your private key files are NOT accessible by others.");
549 error("This private key will be ignored.");
556 key_load_private_type(int type, const char *filename, const char *passphrase,
557 char **commentp, int *perm_ok)
561 fd = open(filename, O_RDONLY);
563 debug("could not open key file '%s': %s", filename,
569 if (!key_perm_ok(fd, filename)) {
572 error("bad permissions: ignore key: %s", filename);
580 return key_load_private_rsa1(fd, filename, passphrase,
586 return key_load_private_pem(fd, type, passphrase, commentp);
596 key_load_private(const char *filename, const char *passphrase,
602 fd = open(filename, O_RDONLY);
604 debug("could not open key file '%s': %s", filename,
608 if (!key_perm_ok(fd, filename)) {
609 error("bad permissions: ignore key: %s", filename);
613 pub = key_load_public_rsa1(fd, filename, commentp);
614 lseek(fd, (off_t) 0, SEEK_SET); /* rewind */
617 prv = key_load_private_pem(fd, KEY_UNSPEC, passphrase, NULL);
618 /* use the filename as a comment for PEM */
620 *commentp = xstrdup(filename);
622 /* it's a SSH v1 key if the public key part is readable */
625 prv = key_load_private_rsa1(fd, filename, passphrase, NULL);
631 key_try_load_public(Key *k, const char *filename, char **commentp)
634 char line[SSH_MAX_PUBKEY_BYTES];
638 f = fopen(filename, "r");
640 while (read_keyfile_line(f, filename, line, sizeof(line),
649 /* Skip leading whitespace. */
650 for (; *cp && (*cp == ' ' || *cp == '\t'); cp++)
653 if (key_read(k, &cp) == 1) {
655 *commentp=xstrdup(filename);
666 /* load public key from ssh v1 private or any pubkey file */
668 key_load_public(const char *filename, char **commentp)
671 char file[MAXPATHLEN];
673 /* try rsa1 private key */
674 pub = key_load_public_type(KEY_RSA1, filename, commentp);
678 /* try rsa1 public key */
679 pub = key_new(KEY_RSA1);
680 if (key_try_load_public(pub, filename, commentp) == 1)
684 /* try ssh2 public key */
685 pub = key_new(KEY_UNSPEC);
686 if (key_try_load_public(pub, filename, commentp) == 1)
688 if ((strlcpy(file, filename, sizeof file) < sizeof(file)) &&
689 (strlcat(file, ".pub", sizeof file) < sizeof(file)) &&
690 (key_try_load_public(pub, file, commentp) == 1))
697 * Returns 1 if the specified "key" is listed in the file "filename",
698 * 0 if the key is not listed or -1 on error.
699 * If strict_type is set then the key type must match exactly,
700 * otherwise a comparison that ignores certficiate data is performed.
703 key_in_file(Key *key, const char *filename, int strict_type)
706 char line[SSH_MAX_PUBKEY_BYTES];
711 int (*key_compare)(const Key *, const Key *) = strict_type ?
712 key_equal : key_equal_public;
714 if ((f = fopen(filename, "r")) == NULL) {
715 if (errno == ENOENT) {
716 debug("%s: keyfile \"%s\" missing", __func__, filename);
719 error("%s: could not open keyfile \"%s\": %s", __func__,
720 filename, strerror(errno));
725 while (read_keyfile_line(f, filename, line, sizeof(line),
729 /* Skip leading whitespace. */
730 for (; *cp && (*cp == ' ' || *cp == '\t'); cp++)
733 /* Skip comments and empty lines */
741 pub = key_new(KEY_UNSPEC);
742 if (key_read(pub, &cp) != 1) {
746 if (key_compare(key, pub)) {