1 /*
2 * Copyright (c) 2000 - 2004 Kungliga Tekniska Högskolan
3 * (Royal Institute of Technology, Stockholm, Sweden).
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 *
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 *
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 *
17 * 3. Neither the name of the Institute nor the names of its contributors
18 * may be used to endorse or promote products derived from this software
19 * without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 */
33
34 #include "hdb_locl.h"
35 #ifndef O_BINARY
36 #define O_BINARY 0
37 #endif
38
39 struct hdb_master_key_data {
40 krb5_keytab_entry keytab;
41 krb5_crypto crypto;
42 struct hdb_master_key_data *next;
43 };
44
45 void
hdb_free_master_key(krb5_context context,hdb_master_key mkey)46 hdb_free_master_key(krb5_context context, hdb_master_key mkey)
47 {
48 struct hdb_master_key_data *ptr;
49 while(mkey) {
50 krb5_kt_free_entry(context, &mkey->keytab);
51 if (mkey->crypto)
52 krb5_crypto_destroy(context, mkey->crypto);
53 ptr = mkey;
54 mkey = mkey->next;
55 free(ptr);
56 }
57 }
58
59 krb5_error_code
hdb_process_master_key(krb5_context context,int kvno,krb5_keyblock * key,krb5_enctype etype,hdb_master_key * mkey)60 hdb_process_master_key(krb5_context context,
61 int kvno, krb5_keyblock *key, krb5_enctype etype,
62 hdb_master_key *mkey)
63 {
64 krb5_error_code ret;
65
66 *mkey = calloc(1, sizeof(**mkey));
67 if(*mkey == NULL) {
68 krb5_set_error_message(context, ENOMEM, "malloc: out of memory");
69 return ENOMEM;
70 }
71 (*mkey)->keytab.vno = kvno;
72 ret = krb5_parse_name(context, "K/M", &(*mkey)->keytab.principal);
73 if(ret)
74 goto fail;
75 ret = krb5_copy_keyblock_contents(context, key, &(*mkey)->keytab.keyblock);
76 if(ret)
77 goto fail;
78 if(etype != 0)
79 (*mkey)->keytab.keyblock.keytype = etype;
80 (*mkey)->keytab.timestamp = time(NULL);
81 ret = krb5_crypto_init(context, key, etype, &(*mkey)->crypto);
82 if(ret)
83 goto fail;
84 return 0;
85 fail:
86 hdb_free_master_key(context, *mkey);
87 *mkey = NULL;
88 return ret;
89 }
90
91 krb5_error_code
hdb_add_master_key(krb5_context context,krb5_keyblock * key,hdb_master_key * inout)92 hdb_add_master_key(krb5_context context, krb5_keyblock *key,
93 hdb_master_key *inout)
94 {
95 int vno = 0;
96 hdb_master_key p;
97 krb5_error_code ret;
98
99 for(p = *inout; p; p = p->next)
100 vno = max(vno, p->keytab.vno);
101 vno++;
102 ret = hdb_process_master_key(context, vno, key, 0, &p);
103 if(ret)
104 return ret;
105 p->next = *inout;
106 *inout = p;
107 return 0;
108 }
109
110 static krb5_error_code
read_master_keytab(krb5_context context,const char * filename,hdb_master_key * mkey)111 read_master_keytab(krb5_context context, const char *filename,
112 hdb_master_key *mkey)
113 {
114 krb5_error_code ret;
115 krb5_keytab id;
116 krb5_kt_cursor cursor;
117 krb5_keytab_entry entry;
118 hdb_master_key p;
119
120 ret = krb5_kt_resolve(context, filename, &id);
121 if(ret)
122 return ret;
123
124 ret = krb5_kt_start_seq_get(context, id, &cursor);
125 if(ret)
126 goto out;
127 *mkey = NULL;
128 while(krb5_kt_next_entry(context, id, &entry, &cursor) == 0) {
129 p = calloc(1, sizeof(*p));
130 if(p == NULL) {
131 krb5_kt_end_seq_get(context, id, &cursor);
132 ret = ENOMEM;
133 goto out;
134 }
135 p->keytab = entry;
136 ret = krb5_crypto_init(context, &p->keytab.keyblock, 0, &p->crypto);
137 p->next = *mkey;
138 *mkey = p;
139 }
140 krb5_kt_end_seq_get(context, id, &cursor);
141 out:
142 krb5_kt_close(context, id);
143 return ret;
144 }
145
146 /* read a MIT master keyfile */
147 static krb5_error_code
read_master_mit(krb5_context context,const char * filename,int byteorder,hdb_master_key * mkey)148 read_master_mit(krb5_context context, const char *filename,
149 int byteorder, hdb_master_key *mkey)
150 {
151 int fd;
152 krb5_error_code ret;
153 krb5_storage *sp;
154 int16_t enctype;
155 krb5_keyblock key;
156
157 fd = open(filename, O_RDONLY | O_BINARY);
158 if(fd < 0) {
159 int save_errno = errno;
160 krb5_set_error_message(context, save_errno, "failed to open %s: %s",
161 filename, strerror(save_errno));
162 return save_errno;
163 }
164 sp = krb5_storage_from_fd(fd);
165 if(sp == NULL) {
166 close(fd);
167 return errno;
168 }
169 krb5_storage_set_flags(sp, byteorder);
170 /* could possibly use ret_keyblock here, but do it with more
171 checks for now */
172 {
173 ret = krb5_ret_int16(sp, &enctype);
174 if (ret)
175 goto out;
176 ret = krb5_enctype_valid(context, enctype);
177 if (ret)
178 goto out;
179 key.keytype = enctype;
180 ret = krb5_ret_data(sp, &key.keyvalue);
181 if(ret)
182 goto out;
183 }
184 ret = hdb_process_master_key(context, 1, &key, 0, mkey);
185 krb5_free_keyblock_contents(context, &key);
186 out:
187 krb5_storage_free(sp);
188 close(fd);
189 return ret;
190 }
191
192 /* read an old master key file */
193 static krb5_error_code
read_master_encryptionkey(krb5_context context,const char * filename,hdb_master_key * mkey)194 read_master_encryptionkey(krb5_context context, const char *filename,
195 hdb_master_key *mkey)
196 {
197 int fd;
198 krb5_keyblock key;
199 krb5_error_code ret;
200 unsigned char buf[256];
201 ssize_t len;
202 size_t ret_len;
203
204 fd = open(filename, O_RDONLY | O_BINARY);
205 if(fd < 0) {
206 int save_errno = errno;
207 krb5_set_error_message(context, save_errno, "failed to open %s: %s",
208 filename, strerror(save_errno));
209 return save_errno;
210 }
211
212 len = read(fd, buf, sizeof(buf));
213 close(fd);
214 if(len < 0) {
215 int save_errno = errno;
216 krb5_set_error_message(context, save_errno, "error reading %s: %s",
217 filename, strerror(save_errno));
218 return save_errno;
219 }
220
221 ret = decode_EncryptionKey(buf, len, &key, &ret_len);
222 memset(buf, 0, sizeof(buf));
223 if(ret)
224 return ret;
225
226 /* Originally, the keytype was just that, and later it got changed
227 to des-cbc-md5, but we always used des in cfb64 mode. This
228 should cover all cases, but will break if someone has hacked
229 this code to really use des-cbc-md5 -- but then that's not my
230 problem. */
231 if(key.keytype == ETYPE_DES_CBC_CRC || key.keytype == ETYPE_DES_CBC_MD5)
232 key.keytype = ETYPE_DES_CFB64_NONE;
233
234 ret = hdb_process_master_key(context, 0, &key, 0, mkey);
235 krb5_free_keyblock_contents(context, &key);
236 return ret;
237 }
238
239 /* read a krb4 /.k style file */
240 static krb5_error_code
read_master_krb4(krb5_context context,const char * filename,hdb_master_key * mkey)241 read_master_krb4(krb5_context context, const char *filename,
242 hdb_master_key *mkey)
243 {
244 int fd;
245 krb5_keyblock key;
246 krb5_error_code ret;
247 unsigned char buf[256];
248 ssize_t len;
249
250 fd = open(filename, O_RDONLY | O_BINARY);
251 if(fd < 0) {
252 int save_errno = errno;
253 krb5_set_error_message(context, save_errno, "failed to open %s: %s",
254 filename, strerror(save_errno));
255 return save_errno;
256 }
257
258 len = read(fd, buf, sizeof(buf));
259 close(fd);
260 if(len < 0) {
261 int save_errno = errno;
262 krb5_set_error_message(context, save_errno, "error reading %s: %s",
263 filename, strerror(save_errno));
264 return save_errno;
265 }
266 if(len != 8) {
267 krb5_set_error_message(context, HEIM_ERR_EOF,
268 "bad contents of %s", filename);
269 return HEIM_ERR_EOF; /* XXX file might be too large */
270 }
271
272 memset(&key, 0, sizeof(key));
273 key.keytype = ETYPE_DES_PCBC_NONE;
274 ret = krb5_data_copy(&key.keyvalue, buf, len);
275 memset(buf, 0, sizeof(buf));
276 if(ret)
277 return ret;
278
279 ret = hdb_process_master_key(context, 0, &key, 0, mkey);
280 krb5_free_keyblock_contents(context, &key);
281 return ret;
282 }
283
284 krb5_error_code
hdb_read_master_key(krb5_context context,const char * filename,hdb_master_key * mkey)285 hdb_read_master_key(krb5_context context, const char *filename,
286 hdb_master_key *mkey)
287 {
288 FILE *f;
289 unsigned char buf[16];
290 krb5_error_code ret;
291
292 off_t len;
293
294 *mkey = NULL;
295
296 if(filename == NULL)
297 filename = HDB_DB_DIR "/m-key";
298
299 f = fopen(filename, "r");
300 if(f == NULL) {
301 int save_errno = errno;
302 krb5_set_error_message(context, save_errno, "failed to open %s: %s",
303 filename, strerror(save_errno));
304 return save_errno;
305 }
306
307 if(fread(buf, 1, 2, f) != 2) {
308 fclose(f);
309 krb5_set_error_message(context, HEIM_ERR_EOF, "end of file reading %s", filename);
310 return HEIM_ERR_EOF;
311 }
312
313 fseek(f, 0, SEEK_END);
314 len = ftell(f);
315
316 if(fclose(f) != 0)
317 return errno;
318
319 if(len < 0)
320 return errno;
321
322 if(len == 8) {
323 ret = read_master_krb4(context, filename, mkey);
324 } else if(buf[0] == 0x30 && len <= 127 && buf[1] == len - 2) {
325 ret = read_master_encryptionkey(context, filename, mkey);
326 } else if(buf[0] == 5 && buf[1] >= 1 && buf[1] <= 2) {
327 ret = read_master_keytab(context, filename, mkey);
328 } else {
329 /*
330 * Check both LittleEndian and BigEndian since they key file
331 * might be moved from a machine with diffrent byte order, or
332 * its running on MacOS X that always uses BE master keys.
333 */
334 ret = read_master_mit(context, filename, KRB5_STORAGE_BYTEORDER_LE, mkey);
335 if (ret)
336 ret = read_master_mit(context, filename, KRB5_STORAGE_BYTEORDER_BE, mkey);
337 }
338 return ret;
339 }
340
341 krb5_error_code
hdb_write_master_key(krb5_context context,const char * filename,hdb_master_key mkey)342 hdb_write_master_key(krb5_context context, const char *filename,
343 hdb_master_key mkey)
344 {
345 krb5_error_code ret;
346 hdb_master_key p;
347 krb5_keytab kt;
348
349 if(filename == NULL)
350 filename = HDB_DB_DIR "/m-key";
351
352 ret = krb5_kt_resolve(context, filename, &kt);
353 if(ret)
354 return ret;
355
356 for(p = mkey; p; p = p->next) {
357 ret = krb5_kt_add_entry(context, kt, &p->keytab);
358 }
359
360 krb5_kt_close(context, kt);
361
362 return ret;
363 }
364
365 hdb_master_key
_hdb_find_master_key(uint32_t * mkvno,hdb_master_key mkey)366 _hdb_find_master_key(uint32_t *mkvno, hdb_master_key mkey)
367 {
368 hdb_master_key ret = NULL;
369 while(mkey) {
370 if(ret == NULL && mkey->keytab.vno == 0)
371 ret = mkey;
372 if(mkvno == NULL) {
373 if(ret == NULL || mkey->keytab.vno > ret->keytab.vno)
374 ret = mkey;
375 } else if((uint32_t)mkey->keytab.vno == *mkvno)
376 return mkey;
377 mkey = mkey->next;
378 }
379 return ret;
380 }
381
382 int
_hdb_mkey_version(hdb_master_key mkey)383 _hdb_mkey_version(hdb_master_key mkey)
384 {
385 return mkey->keytab.vno;
386 }
387
388 int
_hdb_mkey_decrypt(krb5_context context,hdb_master_key key,krb5_key_usage usage,void * ptr,size_t size,krb5_data * res)389 _hdb_mkey_decrypt(krb5_context context, hdb_master_key key,
390 krb5_key_usage usage,
391 void *ptr, size_t size, krb5_data *res)
392 {
393 return krb5_decrypt(context, key->crypto, usage,
394 ptr, size, res);
395 }
396
397 int
_hdb_mkey_encrypt(krb5_context context,hdb_master_key key,krb5_key_usage usage,const void * ptr,size_t size,krb5_data * res)398 _hdb_mkey_encrypt(krb5_context context, hdb_master_key key,
399 krb5_key_usage usage,
400 const void *ptr, size_t size, krb5_data *res)
401 {
402 return krb5_encrypt(context, key->crypto, usage,
403 ptr, size, res);
404 }
405
406 krb5_error_code
hdb_unseal_key_mkey(krb5_context context,Key * k,hdb_master_key mkey)407 hdb_unseal_key_mkey(krb5_context context, Key *k, hdb_master_key mkey)
408 {
409
410 krb5_error_code ret;
411 krb5_data res;
412 size_t keysize;
413
414 hdb_master_key key;
415
416 if(k->mkvno == NULL)
417 return 0;
418
419 key = _hdb_find_master_key(k->mkvno, mkey);
420
421 if (key == NULL)
422 return HDB_ERR_NO_MKEY;
423
424 ret = _hdb_mkey_decrypt(context, key, HDB_KU_MKEY,
425 k->key.keyvalue.data,
426 k->key.keyvalue.length,
427 &res);
428 if(ret == KRB5KRB_AP_ERR_BAD_INTEGRITY) {
429 /* try to decrypt with MIT key usage */
430 ret = _hdb_mkey_decrypt(context, key, 0,
431 k->key.keyvalue.data,
432 k->key.keyvalue.length,
433 &res);
434 }
435 if (ret)
436 return ret;
437
438 /* fixup keylength if the key got padded when encrypting it */
439 ret = krb5_enctype_keysize(context, k->key.keytype, &keysize);
440 if (ret) {
441 krb5_data_free(&res);
442 return ret;
443 }
444 if (keysize > res.length) {
445 krb5_data_free(&res);
446 return KRB5_BAD_KEYSIZE;
447 }
448
449 memset(k->key.keyvalue.data, 0, k->key.keyvalue.length);
450 free(k->key.keyvalue.data);
451 k->key.keyvalue = res;
452 k->key.keyvalue.length = keysize;
453 free(k->mkvno);
454 k->mkvno = NULL;
455
456 return 0;
457 }
458
459 krb5_error_code
hdb_unseal_keys_mkey(krb5_context context,hdb_entry * ent,hdb_master_key mkey)460 hdb_unseal_keys_mkey(krb5_context context, hdb_entry *ent, hdb_master_key mkey)
461 {
462 size_t i;
463
464 for(i = 0; i < ent->keys.len; i++){
465 krb5_error_code ret;
466
467 ret = hdb_unseal_key_mkey(context, &ent->keys.val[i], mkey);
468 if (ret)
469 return ret;
470 }
471 return 0;
472 }
473
474 krb5_error_code
hdb_unseal_keys(krb5_context context,HDB * db,hdb_entry * ent)475 hdb_unseal_keys(krb5_context context, HDB *db, hdb_entry *ent)
476 {
477 if (db->hdb_master_key_set == 0)
478 return 0;
479 return hdb_unseal_keys_mkey(context, ent, db->hdb_master_key);
480 }
481
482 krb5_error_code
hdb_unseal_key(krb5_context context,HDB * db,Key * k)483 hdb_unseal_key(krb5_context context, HDB *db, Key *k)
484 {
485 if (db->hdb_master_key_set == 0)
486 return 0;
487 return hdb_unseal_key_mkey(context, k, db->hdb_master_key);
488 }
489
490 krb5_error_code
hdb_seal_key_mkey(krb5_context context,Key * k,hdb_master_key mkey)491 hdb_seal_key_mkey(krb5_context context, Key *k, hdb_master_key mkey)
492 {
493 krb5_error_code ret;
494 krb5_data res;
495 hdb_master_key key;
496
497 if(k->mkvno != NULL)
498 return 0;
499
500 key = _hdb_find_master_key(k->mkvno, mkey);
501
502 if (key == NULL)
503 return HDB_ERR_NO_MKEY;
504
505 ret = _hdb_mkey_encrypt(context, key, HDB_KU_MKEY,
506 k->key.keyvalue.data,
507 k->key.keyvalue.length,
508 &res);
509 if (ret)
510 return ret;
511
512 memset(k->key.keyvalue.data, 0, k->key.keyvalue.length);
513 free(k->key.keyvalue.data);
514 k->key.keyvalue = res;
515
516 if (k->mkvno == NULL) {
517 k->mkvno = malloc(sizeof(*k->mkvno));
518 if (k->mkvno == NULL)
519 return ENOMEM;
520 }
521 *k->mkvno = key->keytab.vno;
522
523 return 0;
524 }
525
526 krb5_error_code
hdb_seal_keys_mkey(krb5_context context,hdb_entry * ent,hdb_master_key mkey)527 hdb_seal_keys_mkey(krb5_context context, hdb_entry *ent, hdb_master_key mkey)
528 {
529 size_t i;
530 for(i = 0; i < ent->keys.len; i++){
531 krb5_error_code ret;
532
533 ret = hdb_seal_key_mkey(context, &ent->keys.val[i], mkey);
534 if (ret)
535 return ret;
536 }
537 return 0;
538 }
539
540 krb5_error_code
hdb_seal_keys(krb5_context context,HDB * db,hdb_entry * ent)541 hdb_seal_keys(krb5_context context, HDB *db, hdb_entry *ent)
542 {
543 if (db->hdb_master_key_set == 0)
544 return 0;
545
546 return hdb_seal_keys_mkey(context, ent, db->hdb_master_key);
547 }
548
549 krb5_error_code
hdb_seal_key(krb5_context context,HDB * db,Key * k)550 hdb_seal_key(krb5_context context, HDB *db, Key *k)
551 {
552 if (db->hdb_master_key_set == 0)
553 return 0;
554
555 return hdb_seal_key_mkey(context, k, db->hdb_master_key);
556 }
557
558 krb5_error_code
hdb_set_master_key(krb5_context context,HDB * db,krb5_keyblock * key)559 hdb_set_master_key (krb5_context context,
560 HDB *db,
561 krb5_keyblock *key)
562 {
563 krb5_error_code ret;
564 hdb_master_key mkey;
565
566 ret = hdb_process_master_key(context, 0, key, 0, &mkey);
567 if (ret)
568 return ret;
569 db->hdb_master_key = mkey;
570 #if 0 /* XXX - why? */
571 des_set_random_generator_seed(key.keyvalue.data);
572 #endif
573 db->hdb_master_key_set = 1;
574 return 0;
575 }
576
577 krb5_error_code
hdb_set_master_keyfile(krb5_context context,HDB * db,const char * keyfile)578 hdb_set_master_keyfile (krb5_context context,
579 HDB *db,
580 const char *keyfile)
581 {
582 hdb_master_key key;
583 krb5_error_code ret;
584
585 ret = hdb_read_master_key(context, keyfile, &key);
586 if (ret) {
587 if (ret != ENOENT)
588 return ret;
589 krb5_clear_error_message(context);
590 return 0;
591 }
592 db->hdb_master_key = key;
593 db->hdb_master_key_set = 1;
594 return ret;
595 }
596
597 krb5_error_code
hdb_clear_master_key(krb5_context context,HDB * db)598 hdb_clear_master_key (krb5_context context,
599 HDB *db)
600 {
601 if (db->hdb_master_key_set) {
602 hdb_free_master_key(context, db->hdb_master_key);
603 db->hdb_master_key_set = 0;
604 }
605 return 0;
606 }
607