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