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 1.57 2004/06/21 17:36:31 avsm Exp $");
41 #include <openssl/err.h>
42 #include <openssl/evp.h>
43 #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
;
72 int fd
, i
, cipher_num
;
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 cipher_num
= (strcmp(passphrase
, "") == 0) ?
82 SSH_CIPHER_NONE
: SSH_AUTHFILE_CIPHER
;
83 if ((cipher
= cipher_by_number(cipher_num
)) == NULL
)
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] = (rnd
>> 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
->rsa
->d
);
103 buffer_put_bignum(&buffer
, key
->rsa
->iqmp
);
104 buffer_put_bignum(&buffer
, key
->rsa
->q
); /* reverse from SSL p */
105 buffer_put_bignum(&buffer
, key
->rsa
->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 for (i
= 0; authfile_id_string
[i
]; i
++)
116 buffer_put_char(&encrypted
, authfile_id_string
[i
]);
117 buffer_put_char(&encrypted
, 0);
119 /* Store cipher type. */
120 buffer_put_char(&encrypted
, cipher_num
);
121 buffer_put_int(&encrypted
, 0); /* For future extension */
123 /* Store public key. This will be in plain text. */
124 buffer_put_int(&encrypted
, BN_num_bits(key
->rsa
->n
));
125 buffer_put_bignum(&encrypted
, key
->rsa
->n
);
126 buffer_put_bignum(&encrypted
, key
->rsa
->e
);
127 buffer_put_cstring(&encrypted
, comment
);
129 /* Allocate space for the private part of the key in the buffer. */
130 cp
= buffer_append_space(&encrypted
, buffer_len(&buffer
));
132 cipher_set_key_string(&ciphercontext
, cipher
, passphrase
,
134 cipher_crypt(&ciphercontext
, cp
,
135 buffer_ptr(&buffer
), buffer_len(&buffer
));
136 cipher_cleanup(&ciphercontext
);
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
));
146 buffer_free(&encrypted
);
149 if (write(fd
, buffer_ptr(&encrypted
), buffer_len(&encrypted
)) !=
150 buffer_len(&encrypted
)) {
151 error("write to key file %s failed: %s", filename
,
153 buffer_free(&encrypted
);
159 buffer_free(&encrypted
);
163 /* save SSH v2 key in OpenSSL PEM format */
165 key_save_private_pem(Key
*key
, const char *filename
, const char *_passphrase
,
171 int len
= strlen(_passphrase
);
172 u_char
*passphrase
= (len
> 0) ? (u_char
*)_passphrase
: NULL
;
173 const EVP_CIPHER
*cipher
= (len
> 0) ? EVP_des_ede3_cbc() : NULL
;
175 if (len
> 0 && len
<= 4) {
176 error("passphrase too short: have %d bytes, need > 4", len
);
179 fd
= open(filename
, O_WRONLY
| O_CREAT
| O_TRUNC
, 0600);
181 error("open %s failed: %s.", filename
, strerror(errno
));
184 fp
= fdopen(fd
, "w");
186 error("fdopen %s failed: %s.", filename
, strerror(errno
));
192 success
= PEM_write_DSAPrivateKey(fp
, key
->dsa
,
193 cipher
, passphrase
, len
, NULL
, NULL
);
196 success
= PEM_write_RSAPrivateKey(fp
, key
->rsa
,
197 cipher
, passphrase
, len
, NULL
, NULL
);
205 key_save_private(Key
*key
, const char *filename
, const char *passphrase
,
210 return key_save_private_rsa1(key
, filename
, passphrase
,
215 return key_save_private_pem(key
, filename
, passphrase
,
221 error("key_save_private: cannot save key type %d", key
->type
);
226 * Loads the public part of the ssh v1 key file. Returns NULL if an error was
227 * encountered (the file does not exist or is not readable), and the key
232 key_load_public_rsa1(int fd
, const char *filename
, char **commentp
)
241 if (fstat(fd
, &st
) < 0) {
242 error("fstat for key file %.200s failed: %.100s",
243 filename
, strerror(errno
));
246 if (st
.st_size
> 1*1024*1024)
248 len
= (size_t)st
.st_size
; /* truncated */
250 buffer_init(&buffer
);
251 cp
= buffer_append_space(&buffer
, len
);
253 if (read(fd
, cp
, (size_t) len
) != (size_t) len
) {
254 debug("Read from key file %.200s failed: %.100s", filename
,
256 buffer_free(&buffer
);
260 /* Check that it is at least big enough to contain the ID string. */
261 if (len
< sizeof(authfile_id_string
)) {
262 debug3("Not a RSA1 key file %.200s.", filename
);
263 buffer_free(&buffer
);
267 * Make sure it begins with the id string. Consume the id string
270 for (i
= 0; i
< sizeof(authfile_id_string
); i
++)
271 if (buffer_get_char(&buffer
) != authfile_id_string
[i
]) {
272 debug3("Not a RSA1 key file %.200s.", filename
);
273 buffer_free(&buffer
);
276 /* Skip cipher type and reserved data. */
277 (void) buffer_get_char(&buffer
); /* cipher type */
278 (void) buffer_get_int(&buffer
); /* reserved */
280 /* Read the public key from the buffer. */
281 (void) buffer_get_int(&buffer
);
282 pub
= key_new(KEY_RSA1
);
283 buffer_get_bignum(&buffer
, pub
->rsa
->n
);
284 buffer_get_bignum(&buffer
, pub
->rsa
->e
);
286 *commentp
= buffer_get_string(&buffer
, NULL
);
287 /* The encrypted private part is not parsed by this function. */
289 buffer_free(&buffer
);
293 /* load public key from private-key file, works only for SSH v1 */
295 key_load_public_type(int type
, const char *filename
, char **commentp
)
300 if (type
== KEY_RSA1
) {
301 fd
= open(filename
, O_RDONLY
);
304 pub
= key_load_public_rsa1(fd
, filename
, commentp
);
312 * Loads the private key from the file. Returns 0 if an error is encountered
313 * (file does not exist or is not readable, or passphrase is bad). This
314 * initializes the private key.
315 * Assumes we are called under uid of the owner of the file.
319 key_load_private_rsa1(int fd
, const char *filename
, const char *passphrase
,
322 int i
, check1
, check2
, cipher_type
;
324 Buffer buffer
, decrypted
;
326 CipherContext ciphercontext
;
331 if (fstat(fd
, &st
) < 0) {
332 error("fstat for key file %.200s failed: %.100s",
333 filename
, strerror(errno
));
337 if (st
.st_size
> 1*1024*1024) {
341 len
= (size_t)st
.st_size
; /* truncated */
343 buffer_init(&buffer
);
344 cp
= buffer_append_space(&buffer
, len
);
346 if (read(fd
, cp
, (size_t) len
) != (size_t) len
) {
347 debug("Read from key file %.200s failed: %.100s", filename
,
349 buffer_free(&buffer
);
354 /* Check that it is at least big enough to contain the ID string. */
355 if (len
< sizeof(authfile_id_string
)) {
356 debug3("Not a RSA1 key file %.200s.", filename
);
357 buffer_free(&buffer
);
362 * Make sure it begins with the id string. Consume the id string
365 for (i
= 0; i
< sizeof(authfile_id_string
); i
++)
366 if (buffer_get_char(&buffer
) != authfile_id_string
[i
]) {
367 debug3("Not a RSA1 key file %.200s.", filename
);
368 buffer_free(&buffer
);
373 /* Read cipher type. */
374 cipher_type
= buffer_get_char(&buffer
);
375 (void) buffer_get_int(&buffer
); /* Reserved data. */
377 /* Read the public key from the buffer. */
378 (void) buffer_get_int(&buffer
);
379 prv
= key_new_private(KEY_RSA1
);
381 buffer_get_bignum(&buffer
, prv
->rsa
->n
);
382 buffer_get_bignum(&buffer
, prv
->rsa
->e
);
384 *commentp
= buffer_get_string(&buffer
, NULL
);
386 xfree(buffer_get_string(&buffer
, NULL
));
388 /* Check that it is a supported cipher. */
389 cipher
= cipher_by_number(cipher_type
);
390 if (cipher
== NULL
) {
391 debug("Unsupported cipher %d used in key file %.200s.",
392 cipher_type
, filename
);
393 buffer_free(&buffer
);
396 /* Initialize space for decrypted data. */
397 buffer_init(&decrypted
);
398 cp
= buffer_append_space(&decrypted
, buffer_len(&buffer
));
400 /* Rest of the buffer is encrypted. Decrypt it using the passphrase. */
401 cipher_set_key_string(&ciphercontext
, cipher
, passphrase
,
403 cipher_crypt(&ciphercontext
, cp
,
404 buffer_ptr(&buffer
), buffer_len(&buffer
));
405 cipher_cleanup(&ciphercontext
);
406 memset(&ciphercontext
, 0, sizeof(ciphercontext
));
407 buffer_free(&buffer
);
409 check1
= buffer_get_char(&decrypted
);
410 check2
= buffer_get_char(&decrypted
);
411 if (check1
!= buffer_get_char(&decrypted
) ||
412 check2
!= buffer_get_char(&decrypted
)) {
413 if (strcmp(passphrase
, "") != 0)
414 debug("Bad passphrase supplied for key file %.200s.",
416 /* Bad passphrase. */
417 buffer_free(&decrypted
);
420 /* Read the rest of the private key. */
421 buffer_get_bignum(&decrypted
, prv
->rsa
->d
);
422 buffer_get_bignum(&decrypted
, prv
->rsa
->iqmp
); /* u */
423 /* in SSL and SSH v1 p and q are exchanged */
424 buffer_get_bignum(&decrypted
, prv
->rsa
->q
); /* p */
425 buffer_get_bignum(&decrypted
, prv
->rsa
->p
); /* q */
427 /* calculate p-1 and q-1 */
428 rsa_generate_additional_parameters(prv
->rsa
);
430 buffer_free(&decrypted
);
432 /* enable blinding */
433 if (RSA_blinding_on(prv
->rsa
, NULL
) != 1) {
434 error("key_load_private_rsa1: RSA_blinding_on failed");
449 key_load_private_pem(int fd
, int type
, const char *passphrase
,
455 char *name
= "<no key>";
457 fp
= fdopen(fd
, "r");
459 error("fdopen failed: %s", strerror(errno
));
463 pk
= PEM_read_PrivateKey(fp
, NULL
, NULL
, (char *)passphrase
);
465 debug("PEM_read_PrivateKey failed");
466 (void)ERR_get_error();
467 } else if (pk
->type
== EVP_PKEY_RSA
&&
468 (type
== KEY_UNSPEC
||type
==KEY_RSA
)) {
469 prv
= key_new(KEY_UNSPEC
);
470 prv
->rsa
= EVP_PKEY_get1_RSA(pk
);
472 name
= "rsa w/o comment";
474 RSA_print_fp(stderr
, prv
->rsa
, 8);
476 if (RSA_blinding_on(prv
->rsa
, NULL
) != 1) {
477 error("key_load_private_pem: RSA_blinding_on failed");
481 } else if (pk
->type
== EVP_PKEY_DSA
&&
482 (type
== KEY_UNSPEC
||type
==KEY_DSA
)) {
483 prv
= key_new(KEY_UNSPEC
);
484 prv
->dsa
= EVP_PKEY_get1_DSA(pk
);
486 name
= "dsa w/o comment";
488 DSA_print_fp(stderr
, prv
->dsa
, 8);
491 error("PEM_read_PrivateKey: mismatch or "
492 "unknown EVP_PKEY save_type %d", pk
->save_type
);
497 if (prv
!= NULL
&& commentp
)
498 *commentp
= xstrdup(name
);
499 debug("read PEM private key done: type %s",
500 prv
? key_type(prv
) : "<unknown>");
505 key_perm_ok(int fd
, const char *filename
)
509 if (fstat(fd
, &st
) < 0)
512 * if a key owned by the user is accessed, then we check the
513 * permissions of the file. if the key owned by a different user,
514 * then we don't care.
517 if (check_ntsec(filename
))
519 if ((st
.st_uid
== getuid()) && (st
.st_mode
& 077) != 0) {
520 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
521 error("@ WARNING: UNPROTECTED PRIVATE KEY FILE! @");
522 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
523 error("Permissions 0%3.3o for '%s' are too open.",
524 (u_int
)st
.st_mode
& 0777, filename
);
525 error("It is recommended that your private key files are NOT accessible by others.");
526 error("This private key will be ignored.");
533 key_load_private_type(int type
, const char *filename
, const char *passphrase
,
538 fd
= open(filename
, O_RDONLY
);
541 if (!key_perm_ok(fd
, filename
)) {
542 error("bad permissions: ignore key: %s", filename
);
548 return key_load_private_rsa1(fd
, filename
, passphrase
,
555 return key_load_private_pem(fd
, type
, passphrase
, commentp
);
566 key_load_private(const char *filename
, const char *passphrase
,
572 fd
= open(filename
, O_RDONLY
);
575 if (!key_perm_ok(fd
, filename
)) {
576 error("bad permissions: ignore key: %s", filename
);
580 pub
= key_load_public_rsa1(fd
, filename
, commentp
);
581 lseek(fd
, (off_t
) 0, SEEK_SET
); /* rewind */
584 prv
= key_load_private_pem(fd
, KEY_UNSPEC
, passphrase
, NULL
);
585 /* use the filename as a comment for PEM */
587 *commentp
= xstrdup(filename
);
589 /* it's a SSH v1 key if the public key part is readable */
592 prv
= key_load_private_rsa1(fd
, filename
, passphrase
, NULL
);
598 key_try_load_public(Key
*k
, const char *filename
, char **commentp
)
604 f
= fopen(filename
, "r");
606 while (fgets(line
, sizeof(line
), f
)) {
607 line
[sizeof(line
)-1] = '\0';
615 /* Skip leading whitespace. */
616 for (; *cp
&& (*cp
== ' ' || *cp
== '\t'); cp
++)
619 if (key_read(k
, &cp
) == 1) {
621 *commentp
=xstrdup(filename
);
632 /* load public key from ssh v1 private or any pubkey file */
634 key_load_public(const char *filename
, char **commentp
)
637 char file
[MAXPATHLEN
];
639 /* try rsa1 private key */
640 pub
= key_load_public_type(KEY_RSA1
, filename
, commentp
);
644 /* try rsa1 public key */
645 pub
= key_new(KEY_RSA1
);
646 if (key_try_load_public(pub
, filename
, commentp
) == 1)
650 /* try ssh2 public key */
651 pub
= key_new(KEY_UNSPEC
);
652 if (key_try_load_public(pub
, filename
, commentp
) == 1)
654 if ((strlcpy(file
, filename
, sizeof file
) < sizeof(file
)) &&
655 (strlcat(file
, ".pub", sizeof file
) < sizeof(file
)) &&
656 (key_try_load_public(pub
, file
, commentp
) == 1))