diff options
author | Damien Miller <djm@mindrot.org> | 1999-10-27 13:42:43 +1000 |
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committer | Damien Miller <djm@mindrot.org> | 1999-10-27 13:42:43 +1000 |
commit | d4a8b7e34dd619a4debf9a206c81db26d1402ea6 (patch) | |
tree | a47d770a2f790f40d18b0982d4e55fa7cfb1fa3b /authfile.c |
Initial revision
Diffstat (limited to 'authfile.c')
-rw-r--r-- | authfile.c | 350 |
1 files changed, 350 insertions, 0 deletions
diff --git a/authfile.c b/authfile.c new file mode 100644 index 000000000..49390e083 --- /dev/null +++ b/authfile.c | |||
@@ -0,0 +1,350 @@ | |||
1 | /* | ||
2 | |||
3 | authfile.c | ||
4 | |||
5 | Author: Tatu Ylonen <ylo@cs.hut.fi> | ||
6 | |||
7 | Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland | ||
8 | All rights reserved | ||
9 | |||
10 | Created: Mon Mar 27 03:52:05 1995 ylo | ||
11 | |||
12 | This file contains functions for reading and writing identity files, and | ||
13 | for reading the passphrase from the user. | ||
14 | |||
15 | */ | ||
16 | |||
17 | #include "includes.h" | ||
18 | RCSID("$Id: authfile.c,v 1.1 1999/10/27 03:42:43 damien Exp $"); | ||
19 | |||
20 | #include <openssl/bn.h> | ||
21 | #include "xmalloc.h" | ||
22 | #include "buffer.h" | ||
23 | #include "bufaux.h" | ||
24 | #include "cipher.h" | ||
25 | #include "ssh.h" | ||
26 | |||
27 | /* Version identification string for identity files. */ | ||
28 | #define AUTHFILE_ID_STRING "SSH PRIVATE KEY FILE FORMAT 1.1\n" | ||
29 | |||
30 | /* Saves the authentication (private) key in a file, encrypting it with | ||
31 | passphrase. The identification of the file (lowest 64 bits of n) | ||
32 | will precede the key to provide identification of the key without | ||
33 | needing a passphrase. */ | ||
34 | |||
35 | int | ||
36 | save_private_key(const char *filename, const char *passphrase, | ||
37 | RSA *key, const char *comment) | ||
38 | { | ||
39 | Buffer buffer, encrypted; | ||
40 | char buf[100], *cp; | ||
41 | int f, i; | ||
42 | CipherContext cipher; | ||
43 | int cipher_type; | ||
44 | u_int32_t rand; | ||
45 | |||
46 | /* If the passphrase is empty, use SSH_CIPHER_NONE to ease converting to | ||
47 | another cipher; otherwise use SSH_AUTHFILE_CIPHER. */ | ||
48 | if (strcmp(passphrase, "") == 0) | ||
49 | cipher_type = SSH_CIPHER_NONE; | ||
50 | else | ||
51 | cipher_type = SSH_AUTHFILE_CIPHER; | ||
52 | |||
53 | /* This buffer is used to built the secret part of the private key. */ | ||
54 | buffer_init(&buffer); | ||
55 | |||
56 | /* Put checkbytes for checking passphrase validity. */ | ||
57 | rand = arc4random(); | ||
58 | buf[0] = rand & 0xff; | ||
59 | buf[1] = (rand >> 8) & 0xff; | ||
60 | buf[2] = buf[0]; | ||
61 | buf[3] = buf[1]; | ||
62 | buffer_append(&buffer, buf, 4); | ||
63 | |||
64 | /* Store the private key (n and e will not be stored because they will | ||
65 | be stored in plain text, and storing them also in encrypted format | ||
66 | would just give known plaintext). */ | ||
67 | buffer_put_bignum(&buffer, key->d); | ||
68 | buffer_put_bignum(&buffer, key->iqmp); | ||
69 | buffer_put_bignum(&buffer, key->q); /* reverse from SSL p */ | ||
70 | buffer_put_bignum(&buffer, key->p); /* reverse from SSL q */ | ||
71 | |||
72 | /* Pad the part to be encrypted until its size is a multiple of 8. */ | ||
73 | while (buffer_len(&buffer) % 8 != 0) | ||
74 | buffer_put_char(&buffer, 0); | ||
75 | |||
76 | /* This buffer will be used to contain the data in the file. */ | ||
77 | buffer_init(&encrypted); | ||
78 | |||
79 | /* First store keyfile id string. */ | ||
80 | cp = AUTHFILE_ID_STRING; | ||
81 | for (i = 0; cp[i]; i++) | ||
82 | buffer_put_char(&encrypted, cp[i]); | ||
83 | buffer_put_char(&encrypted, 0); | ||
84 | |||
85 | /* Store cipher type. */ | ||
86 | buffer_put_char(&encrypted, cipher_type); | ||
87 | buffer_put_int(&encrypted, 0); /* For future extension */ | ||
88 | |||
89 | /* Store public key. This will be in plain text. */ | ||
90 | buffer_put_int(&encrypted, BN_num_bits(key->n)); | ||
91 | buffer_put_bignum(&encrypted, key->n); | ||
92 | buffer_put_bignum(&encrypted, key->e); | ||
93 | buffer_put_string(&encrypted, comment, strlen(comment)); | ||
94 | |||
95 | /* Allocate space for the private part of the key in the buffer. */ | ||
96 | buffer_append_space(&encrypted, &cp, buffer_len(&buffer)); | ||
97 | |||
98 | cipher_set_key_string(&cipher, cipher_type, passphrase, 1); | ||
99 | cipher_encrypt(&cipher, (unsigned char *)cp, | ||
100 | (unsigned char *)buffer_ptr(&buffer), | ||
101 | buffer_len(&buffer)); | ||
102 | memset(&cipher, 0, sizeof(cipher)); | ||
103 | |||
104 | /* Destroy temporary data. */ | ||
105 | memset(buf, 0, sizeof(buf)); | ||
106 | buffer_free(&buffer); | ||
107 | |||
108 | /* Write to a file. */ | ||
109 | f = open(filename, O_WRONLY|O_CREAT|O_TRUNC, 0600); | ||
110 | if (f < 0) | ||
111 | return 0; | ||
112 | |||
113 | if (write(f, buffer_ptr(&encrypted), buffer_len(&encrypted)) != | ||
114 | buffer_len(&encrypted)) | ||
115 | { | ||
116 | debug("Write to key file %.200s failed: %.100s", filename, | ||
117 | strerror(errno)); | ||
118 | buffer_free(&encrypted); | ||
119 | close(f); | ||
120 | remove(filename); | ||
121 | return 0; | ||
122 | } | ||
123 | close(f); | ||
124 | buffer_free(&encrypted); | ||
125 | return 1; | ||
126 | } | ||
127 | |||
128 | /* Loads the public part of the key file. Returns 0 if an error | ||
129 | was encountered (the file does not exist or is not readable), and | ||
130 | non-zero otherwise. */ | ||
131 | |||
132 | int | ||
133 | load_public_key(const char *filename, RSA *pub, | ||
134 | char **comment_return) | ||
135 | { | ||
136 | int f, i; | ||
137 | off_t len; | ||
138 | Buffer buffer; | ||
139 | char *cp; | ||
140 | |||
141 | /* Read data from the file into the buffer. */ | ||
142 | f = open(filename, O_RDONLY); | ||
143 | if (f < 0) | ||
144 | return 0; | ||
145 | |||
146 | len = lseek(f, (off_t)0, SEEK_END); | ||
147 | lseek(f, (off_t)0, SEEK_SET); | ||
148 | |||
149 | buffer_init(&buffer); | ||
150 | buffer_append_space(&buffer, &cp, len); | ||
151 | |||
152 | if (read(f, cp, (size_t)len) != (size_t)len) | ||
153 | { | ||
154 | debug("Read from key file %.200s failed: %.100s", filename, | ||
155 | strerror(errno)); | ||
156 | buffer_free(&buffer); | ||
157 | close(f); | ||
158 | return 0; | ||
159 | } | ||
160 | close(f); | ||
161 | |||
162 | /* Check that it is at least big enought to contain the ID string. */ | ||
163 | if (len < strlen(AUTHFILE_ID_STRING) + 1) | ||
164 | { | ||
165 | debug("Bad key file %.200s.", filename); | ||
166 | buffer_free(&buffer); | ||
167 | return 0; | ||
168 | } | ||
169 | |||
170 | /* Make sure it begins with the id string. Consume the id string from | ||
171 | the buffer. */ | ||
172 | for (i = 0; i < (unsigned int)strlen(AUTHFILE_ID_STRING) + 1; i++) | ||
173 | if (buffer_get_char(&buffer) != (unsigned char)AUTHFILE_ID_STRING[i]) | ||
174 | { | ||
175 | debug("Bad key file %.200s.", filename); | ||
176 | buffer_free(&buffer); | ||
177 | return 0; | ||
178 | } | ||
179 | |||
180 | /* Skip cipher type and reserved data. */ | ||
181 | (void)buffer_get_char(&buffer); /* cipher type */ | ||
182 | (void)buffer_get_int(&buffer); /* reserved */ | ||
183 | |||
184 | /* Read the public key from the buffer. */ | ||
185 | buffer_get_int(&buffer); | ||
186 | pub->n = BN_new(); | ||
187 | buffer_get_bignum(&buffer, pub->n); | ||
188 | pub->e = BN_new(); | ||
189 | buffer_get_bignum(&buffer, pub->e); | ||
190 | if (comment_return) | ||
191 | *comment_return = buffer_get_string(&buffer, NULL); | ||
192 | /* The encrypted private part is not parsed by this function. */ | ||
193 | |||
194 | buffer_free(&buffer); | ||
195 | |||
196 | return 1; | ||
197 | } | ||
198 | |||
199 | /* Loads the private key from the file. Returns 0 if an error is encountered | ||
200 | (file does not exist or is not readable, or passphrase is bad). | ||
201 | This initializes the private key. */ | ||
202 | |||
203 | int | ||
204 | load_private_key(const char *filename, const char *passphrase, | ||
205 | RSA *prv, char **comment_return) | ||
206 | { | ||
207 | int f, i, check1, check2, cipher_type; | ||
208 | off_t len; | ||
209 | Buffer buffer, decrypted; | ||
210 | char *cp; | ||
211 | CipherContext cipher; | ||
212 | BN_CTX *ctx; | ||
213 | BIGNUM *aux; | ||
214 | struct stat st; | ||
215 | |||
216 | /* Read the file into the buffer. */ | ||
217 | f = open(filename, O_RDONLY); | ||
218 | if (f < 0) | ||
219 | return 0; | ||
220 | |||
221 | /* We assume we are called under uid of the owner of the file */ | ||
222 | if (fstat(f, &st) < 0 || | ||
223 | (st.st_uid != 0 && st.st_uid != getuid()) || | ||
224 | (st.st_mode & 077) != 0) { | ||
225 | error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@"); | ||
226 | error("@ WARNING: UNPROTECTED PRIVATE KEY FILE! @"); | ||
227 | error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@"); | ||
228 | error("Bad ownership or mode(0%3.3o) for '%s'.", | ||
229 | st.st_mode & 0777, filename); | ||
230 | error("It is recommended that your private key files are NOT accessible by others."); | ||
231 | return 0; | ||
232 | } | ||
233 | |||
234 | len = lseek(f, (off_t)0, SEEK_END); | ||
235 | lseek(f, (off_t)0, SEEK_SET); | ||
236 | |||
237 | buffer_init(&buffer); | ||
238 | buffer_append_space(&buffer, &cp, len); | ||
239 | |||
240 | if (read(f, cp, (size_t)len) != (size_t)len) | ||
241 | { | ||
242 | debug("Read from key file %.200s failed: %.100s", filename, | ||
243 | strerror(errno)); | ||
244 | buffer_free(&buffer); | ||
245 | close(f); | ||
246 | return 0; | ||
247 | } | ||
248 | close(f); | ||
249 | |||
250 | /* Check that it is at least big enought to contain the ID string. */ | ||
251 | if (len < strlen(AUTHFILE_ID_STRING) + 1) | ||
252 | { | ||
253 | debug("Bad key file %.200s.", filename); | ||
254 | buffer_free(&buffer); | ||
255 | return 0; | ||
256 | } | ||
257 | |||
258 | /* Make sure it begins with the id string. Consume the id string from | ||
259 | the buffer. */ | ||
260 | for (i = 0; i < (unsigned int)strlen(AUTHFILE_ID_STRING) + 1; i++) | ||
261 | if (buffer_get_char(&buffer) != (unsigned char)AUTHFILE_ID_STRING[i]) | ||
262 | { | ||
263 | debug("Bad key file %.200s.", filename); | ||
264 | buffer_free(&buffer); | ||
265 | return 0; | ||
266 | } | ||
267 | |||
268 | /* Read cipher type. */ | ||
269 | cipher_type = buffer_get_char(&buffer); | ||
270 | (void)buffer_get_int(&buffer); /* Reserved data. */ | ||
271 | |||
272 | /* Read the public key from the buffer. */ | ||
273 | buffer_get_int(&buffer); | ||
274 | prv->n = BN_new(); | ||
275 | buffer_get_bignum(&buffer, prv->n); | ||
276 | prv->e = BN_new(); | ||
277 | buffer_get_bignum(&buffer, prv->e); | ||
278 | if (comment_return) | ||
279 | *comment_return = buffer_get_string(&buffer, NULL); | ||
280 | else | ||
281 | xfree(buffer_get_string(&buffer, NULL)); | ||
282 | |||
283 | /* Check that it is a supported cipher. */ | ||
284 | if (((cipher_mask() | SSH_CIPHER_NONE | SSH_AUTHFILE_CIPHER) & | ||
285 | (1 << cipher_type)) == 0) | ||
286 | { | ||
287 | debug("Unsupported cipher %.100s used in key file %.200s.", | ||
288 | cipher_name(cipher_type), filename); | ||
289 | buffer_free(&buffer); | ||
290 | goto fail; | ||
291 | } | ||
292 | |||
293 | /* Initialize space for decrypted data. */ | ||
294 | buffer_init(&decrypted); | ||
295 | buffer_append_space(&decrypted, &cp, buffer_len(&buffer)); | ||
296 | |||
297 | /* Rest of the buffer is encrypted. Decrypt it using the passphrase. */ | ||
298 | cipher_set_key_string(&cipher, cipher_type, passphrase, 0); | ||
299 | cipher_decrypt(&cipher, (unsigned char *)cp, | ||
300 | (unsigned char *)buffer_ptr(&buffer), | ||
301 | buffer_len(&buffer)); | ||
302 | |||
303 | buffer_free(&buffer); | ||
304 | |||
305 | check1 = buffer_get_char(&decrypted); | ||
306 | check2 = buffer_get_char(&decrypted); | ||
307 | if (check1 != buffer_get_char(&decrypted) || | ||
308 | check2 != buffer_get_char(&decrypted)) | ||
309 | { | ||
310 | if (strcmp(passphrase, "") != 0) | ||
311 | debug("Bad passphrase supplied for key file %.200s.", filename); | ||
312 | /* Bad passphrase. */ | ||
313 | buffer_free(&decrypted); | ||
314 | fail: | ||
315 | BN_clear_free(prv->n); | ||
316 | BN_clear_free(prv->e); | ||
317 | if (comment_return) | ||
318 | xfree(*comment_return); | ||
319 | return 0; | ||
320 | } | ||
321 | |||
322 | /* Read the rest of the private key. */ | ||
323 | prv->d = BN_new(); | ||
324 | buffer_get_bignum(&decrypted, prv->d); | ||
325 | prv->iqmp = BN_new(); | ||
326 | buffer_get_bignum(&decrypted, prv->iqmp); /* u */ | ||
327 | /* in SSL and SSH p and q are exchanged */ | ||
328 | prv->q = BN_new(); | ||
329 | buffer_get_bignum(&decrypted, prv->q); /* p */ | ||
330 | prv->p = BN_new(); | ||
331 | buffer_get_bignum(&decrypted, prv->p); /* q */ | ||
332 | |||
333 | ctx = BN_CTX_new(); | ||
334 | aux = BN_new(); | ||
335 | |||
336 | BN_sub(aux, prv->q, BN_value_one()); | ||
337 | prv->dmq1 = BN_new(); | ||
338 | BN_mod(prv->dmq1, prv->d, aux, ctx); | ||
339 | |||
340 | BN_sub(aux, prv->p, BN_value_one()); | ||
341 | prv->dmp1 = BN_new(); | ||
342 | BN_mod(prv->dmp1, prv->d, aux, ctx); | ||
343 | |||
344 | BN_clear_free(aux); | ||
345 | BN_CTX_free(ctx); | ||
346 | |||
347 | buffer_free(&decrypted); | ||
348 | |||
349 | return 1; | ||
350 | } | ||