1
2/*
3 * Copyright (c) 1997 - 2011 Kungliga Tekniska Högskolan
4 * (Royal Institute of Technology, Stockholm, Sweden).
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 *
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 *
14 * 2. Redistributions in binary form must reproduce the above copyright
15 *    notice, this list of conditions and the following disclaimer in the
16 *    documentation and/or other materials provided with the distribution.
17 *
18 * 3. Neither the name of the Institute nor the names of its contributors
19 *    may be used to endorse or promote products derived from this software
20 *    without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 */
34
35#include "hdb_locl.h"
36
37/*
38 * free all the memory used by (len, keys)
39 */
40
41void
42hdb_free_keys(krb5_context context, size_t len, Key *keys)
43{
44    size_t i;
45
46    for (i = 0; i < len; i++) {
47	free(keys[i].mkvno);
48	keys[i].mkvno = NULL;
49	if (keys[i].salt != NULL) {
50	    free_Salt(keys[i].salt);
51	    free(keys[i].salt);
52	    keys[i].salt = NULL;
53	}
54	krb5_free_keyblock_contents(context, &keys[i].key);
55    }
56    free (keys);
57}
58
59/*
60 * for each entry in `default_keys' try to parse it as a sequence
61 * of etype:salttype:salt, syntax of this if something like:
62 * [(des|des3|etype):](pw-salt|afs3)[:string], if etype is omitted it
63 *      means all etypes, and if string is omitted is means the default
64 * string (for that principal). Additional special values:
65 *	v5 == pw-salt, and
66 *	v4 == des:pw-salt:
67 *	afs or afs3 == des:afs3-salt
68 */
69
70static const krb5_enctype des_etypes[] = {
71    KRB5_ENCTYPE_DES_CBC_MD5,
72    KRB5_ENCTYPE_DES_CBC_MD4,
73    KRB5_ENCTYPE_DES_CBC_CRC
74};
75
76static const krb5_enctype all_etypes[] = {
77    KRB5_ENCTYPE_AES256_CTS_HMAC_SHA1_96,
78    KRB5_ENCTYPE_ARCFOUR_HMAC_MD5,
79    KRB5_ENCTYPE_DES3_CBC_SHA1
80};
81
82static krb5_error_code
83parse_key_set(krb5_context context, const char *key,
84	      krb5_enctype **ret_enctypes, size_t *ret_num_enctypes,
85	      krb5_salt *salt, krb5_principal principal)
86{
87    const char *p;
88    char buf[3][256];
89    int num_buf = 0;
90    int i, num_enctypes = 0;
91    krb5_enctype e;
92    const krb5_enctype *enctypes = NULL;
93    krb5_error_code ret;
94
95    p = key;
96
97    *ret_enctypes = NULL;
98    *ret_num_enctypes = 0;
99
100    /* split p in a list of :-separated strings */
101    for(num_buf = 0; num_buf < 3; num_buf++)
102	if(strsep_copy(&p, ":", buf[num_buf], sizeof(buf[num_buf])) == -1)
103	    break;
104
105    salt->saltvalue.data = NULL;
106    salt->saltvalue.length = 0;
107
108    for(i = 0; i < num_buf; i++) {
109	if(enctypes == NULL && num_buf > 1) {
110	    /* this might be a etype specifier */
111	    /* XXX there should be a string_to_etypes handling
112	       special cases like `des' and `all' */
113	    if(strcmp(buf[i], "des") == 0) {
114		enctypes = des_etypes;
115		num_enctypes = sizeof(des_etypes)/sizeof(des_etypes[0]);
116	    } else if(strcmp(buf[i], "des3") == 0) {
117		e = KRB5_ENCTYPE_DES3_CBC_SHA1;
118		enctypes = &e;
119		num_enctypes = 1;
120	    } else {
121		ret = krb5_string_to_enctype(context, buf[i], &e);
122		if (ret == 0) {
123		    enctypes = &e;
124		    num_enctypes = 1;
125		} else
126		    return ret;
127	    }
128	    continue;
129	}
130	if(salt->salttype == 0) {
131	    /* interpret string as a salt specifier, if no etype
132	       is set, this sets default values */
133	    /* XXX should perhaps use string_to_salttype, but that
134	       interface sucks */
135	    if(strcmp(buf[i], "pw-salt") == 0) {
136		if(enctypes == NULL) {
137		    enctypes = all_etypes;
138		    num_enctypes = sizeof(all_etypes)/sizeof(all_etypes[0]);
139		}
140		salt->salttype = KRB5_PW_SALT;
141	    } else if(strcmp(buf[i], "afs3-salt") == 0) {
142		if(enctypes == NULL) {
143		    enctypes = des_etypes;
144		    num_enctypes = sizeof(des_etypes)/sizeof(des_etypes[0]);
145		}
146		salt->salttype = KRB5_AFS3_SALT;
147	    }
148	    continue;
149	}
150
151	{
152	    /* if there is a final string, use it as the string to
153	       salt with, this is mostly useful with null salt for
154	       v4 compat, and a cell name for afs compat */
155	    salt->saltvalue.data = strdup(buf[i]);
156	    if (salt->saltvalue.data == NULL) {
157		krb5_set_error_message(context, ENOMEM, "malloc: out of memory");
158		return ENOMEM;
159	    }
160	    salt->saltvalue.length = strlen(buf[i]);
161	}
162    }
163
164    if(enctypes == NULL || salt->salttype == 0) {
165	krb5_set_error_message(context, EINVAL, "bad value for default_keys `%s'", key);
166	return EINVAL;
167    }
168
169    /* if no salt was specified make up default salt */
170    if(salt->saltvalue.data == NULL) {
171	if(salt->salttype == KRB5_PW_SALT) {
172	    ret = krb5_get_pw_salt(context, principal, salt);
173	    if (ret)
174		return ret;
175	} else if(salt->salttype == KRB5_AFS3_SALT) {
176	    krb5_const_realm realm = krb5_principal_get_realm(context, principal);
177	    salt->saltvalue.data = strdup(realm);
178	    if(salt->saltvalue.data == NULL) {
179		krb5_set_error_message(context, ENOMEM,
180				       "out of memory while "
181				       "parsing salt specifiers");
182		return ENOMEM;
183	    }
184	    strlwr(salt->saltvalue.data);
185	    salt->saltvalue.length = strlen(realm);
186	}
187    }
188
189    *ret_enctypes = malloc(sizeof(enctypes[0]) * num_enctypes);
190    if (*ret_enctypes == NULL) {
191	krb5_free_salt(context, *salt);
192	krb5_set_error_message(context, ENOMEM, "malloc: out of memory");
193	return ENOMEM;
194    }
195    memcpy(*ret_enctypes, enctypes, sizeof(enctypes[0]) * num_enctypes);
196    *ret_num_enctypes = num_enctypes;
197
198    return 0;
199}
200
201
202/**
203 * This function adds an HDB entry's current keyset to the entry's key
204 * history.  The current keyset is left alone; the caller is responsible
205 * for freeing it.
206 *
207 * @param context   Context
208 * @param entry	    HDB entry
209 */
210krb5_error_code
211hdb_add_current_keys_to_history(krb5_context context, hdb_entry *entry)
212{
213    krb5_boolean replace = FALSE;
214    krb5_error_code ret;
215    HDB_extension *ext;
216    hdb_keyset newkeyset;
217    time_t newtime;
218
219    if (entry->keys.len == 0)
220	return 0; /* nothing to do */
221
222    ext = hdb_find_extension(entry, choice_HDB_extension_data_hist_keys);
223    if (ext == NULL) {
224	replace = TRUE;
225	ext = calloc(1, sizeof (*ext));
226	if (ext == NULL)
227	    return krb5_enomem(context);
228
229	ext->data.element = choice_HDB_extension_data_hist_keys;
230    }
231
232    /*
233     * Copy in newest old keyset
234     */
235    ret = hdb_entry_get_pw_change_time(entry, &newtime);
236    if (ret)
237	goto out;
238
239    memset(&newkeyset, 0, sizeof(newkeyset));
240    newkeyset.keys = entry->keys;
241    newkeyset.kvno = entry->kvno;
242    newkeyset.set_time = &newtime;
243
244    ret = add_HDB_Ext_KeySet(&ext->data.u.hist_keys, &newkeyset);
245    if (ret)
246	goto out;
247
248    if (replace) {
249	/* hdb_replace_extension() deep-copies ext; what a waste */
250	ret = hdb_replace_extension(context, entry, ext);
251	if (ret)
252	    goto out;
253    }
254
255 out:
256    if (replace && ext) {
257	free_HDB_extension(ext);
258	free(ext);
259    }
260    return ret;
261}
262
263/**
264 * This function adds a key to an HDB entry's key history.
265 *
266 * @param context   Context
267 * @param entry	    HDB entry
268 * @param kvno	    Key version number of the key to add to the history
269 * @param key	    The Key to add
270 */
271krb5_error_code
272hdb_add_history_key(krb5_context context, hdb_entry *entry, krb5_kvno kvno, Key *key)
273{
274    size_t i;
275    hdb_keyset keyset;
276    HDB_Ext_KeySet *hist_keys;
277    HDB_extension ext;
278    HDB_extension *extp;
279    krb5_error_code ret;
280
281    memset(&keyset, 0, sizeof (keyset));
282    memset(&ext, 0, sizeof (ext));
283
284    extp = hdb_find_extension(entry, choice_HDB_extension_data_hist_keys);
285    if (extp == NULL) {
286	ext.data.element = choice_HDB_extension_data_hist_keys;
287	extp = &ext;
288    }
289
290    hist_keys = &extp->data.u.hist_keys;
291
292    for (i = 0; i < hist_keys->len; i++) {
293	if (hist_keys->val[i].kvno == kvno) {
294	    ret = add_Keys(&hist_keys->val[i].keys, key);
295	    goto out;
296	}
297    }
298
299    keyset.kvno = kvno;
300    ret = add_Keys(&keyset.keys, key);
301    if (ret)
302	goto out;
303    ret = add_HDB_Ext_KeySet(hist_keys, &keyset);
304    if (ret)
305	goto out;
306    if (extp == &ext) {
307	ret = hdb_replace_extension(context, entry, &ext);
308	if (ret)
309	    goto out;
310    }
311
312out:
313    free_hdb_keyset(&keyset);
314    free_HDB_extension(&ext);
315    return ret;
316}
317
318
319/**
320 * This function changes an hdb_entry's kvno, swapping the current key
321 * set with a historical keyset.  If no historical keys are found then
322 * an error is returned (the caller can still set entry->kvno directly).
323 *
324 * @param context	krb5_context
325 * @param new_kvno	New kvno for the entry
326 * @param entry		hdb_entry to modify
327 */
328krb5_error_code
329hdb_change_kvno(krb5_context context, krb5_kvno new_kvno, hdb_entry *entry)
330{
331    HDB_extension ext;
332    HDB_extension *extp;
333    hdb_keyset keyset;
334    HDB_Ext_KeySet *hist_keys;
335    unsigned int i;
336    int found = 0;
337    krb5_error_code ret;
338
339    if (entry->kvno == new_kvno)
340	return 0;
341
342    extp = hdb_find_extension(entry, choice_HDB_extension_data_hist_keys);
343    if (extp == NULL) {
344	memset(&ext, 0, sizeof (ext));
345	ext.data.element = choice_HDB_extension_data_hist_keys;
346	extp = &ext;
347    }
348
349    memset(&keyset, 0, sizeof (keyset));
350    hist_keys = &extp->data.u.hist_keys;
351    for (i = 0; i < hist_keys->len; i++) {
352	if (hist_keys->val[i].kvno == new_kvno) {
353	    found = 1;
354	    ret = copy_hdb_keyset(&hist_keys->val[i], &keyset);
355	    if (ret)
356		goto out;
357	    ret = remove_HDB_Ext_KeySet(hist_keys, i);
358	    if (ret)
359		goto out;
360	    break;
361	}
362    }
363
364    if (!found)
365	return HDB_ERR_KVNO_NOT_FOUND;
366
367    ret = hdb_add_current_keys_to_history(context, entry);
368    if (ret)
369	goto out;
370
371    /* Note: we do nothing with keyset.set_time */
372    entry->kvno = new_kvno;
373    entry->keys = keyset.keys; /* shortcut */
374    memset(&keyset.keys, 0, sizeof (keyset.keys));
375
376out:
377    free_hdb_keyset(&keyset);
378    return ret;
379}
380
381
382static krb5_error_code
383add_enctype_to_key_set(Key **key_set, size_t *nkeyset,
384		       krb5_enctype enctype, krb5_salt *salt)
385{
386    krb5_error_code ret;
387    Key key, *tmp;
388
389    memset(&key, 0, sizeof(key));
390
391    tmp = realloc(*key_set, (*nkeyset + 1) * sizeof((*key_set)[0]));
392    if (tmp == NULL)
393	return ENOMEM;
394
395    *key_set = tmp;
396
397    key.key.keytype = enctype;
398    key.key.keyvalue.length = 0;
399    key.key.keyvalue.data = NULL;
400
401    if (salt) {
402	key.salt = calloc(1, sizeof(*key.salt));
403	if (key.salt == NULL) {
404	    free_Key(&key);
405	    return ENOMEM;
406	}
407
408	key.salt->type = salt->salttype;
409	krb5_data_zero (&key.salt->salt);
410
411	ret = krb5_data_copy(&key.salt->salt,
412			     salt->saltvalue.data,
413			     salt->saltvalue.length);
414	if (ret) {
415	    free_Key(&key);
416	    return ret;
417	}
418    } else
419	key.salt = NULL;
420
421    (*key_set)[*nkeyset] = key;
422
423    *nkeyset += 1;
424
425    return 0;
426}
427
428
429static
430krb5_error_code
431ks_tuple2str(krb5_context context, int n_ks_tuple,
432	     krb5_key_salt_tuple *ks_tuple, char ***ks_tuple_strs)
433{
434	size_t i;
435	char **ksnames;
436	char *ename, *sname;
437	krb5_error_code rc = KRB5_PROG_ETYPE_NOSUPP;
438
439	*ks_tuple_strs = NULL;
440	if (n_ks_tuple < 1)
441		return 0;
442
443	if ((ksnames = calloc(n_ks_tuple, sizeof (*ksnames))) == NULL)
444		return (errno);
445
446	for (i = 0; i < n_ks_tuple; i++) {
447	    if (krb5_enctype_to_string(context, ks_tuple[i].ks_enctype, &ename))
448		goto out;
449	    if (krb5_salttype_to_string(context, ks_tuple[i].ks_enctype,
450					ks_tuple[i].ks_salttype, &sname))
451		goto out;
452
453	    if (asprintf(&ksnames[i], "%s:%s", ename, sname) == -1) {
454		    rc = errno;
455		    free(ename);
456		    free(sname);
457		    goto out;
458	    }
459	    free(ename);
460	    free(sname);
461	}
462
463	*ks_tuple_strs = ksnames;
464	rc = 0;
465
466out:
467	for (i = 0; i < n_ks_tuple; i++)
468		free(ksnames[i]);
469	free(ksnames);
470	return (rc);
471}
472
473/*
474 * Generate the `key_set' from the [kadmin]default_keys statement. If
475 * `no_salt' is set, salt is not important (and will not be set) since
476 * it's random keys that is going to be created.
477 */
478
479krb5_error_code
480hdb_generate_key_set(krb5_context context, krb5_principal principal,
481		     int n_ks_tuple, krb5_key_salt_tuple *ks_tuple,
482		     Key **ret_key_set, size_t *nkeyset, int no_salt)
483{
484    char **ktypes = NULL;
485    char **kp;
486    krb5_error_code ret;
487    Key *k, *key_set;
488    size_t i, j;
489    char **ks_tuple_strs;
490    static const char *default_keytypes[] = {
491	"aes256-cts-hmac-sha1-96:pw-salt",
492	"aes128-cts-hmac-sha1-96:pw-salt",
493	"des3-cbc-sha1:pw-salt",
494	NULL
495    };
496
497    *ret_key_set = key_set = NULL;
498    *nkeyset = 0;
499
500    if ((ret = ks_tuple2str(context, n_ks_tuple, ks_tuple, &ks_tuple_strs)))
501	    return ret;
502
503    if (ks_tuple_strs == NULL)
504	ktypes = krb5_config_get_strings(context, NULL, "kadmin",
505					 "default_keys", NULL);
506
507    if (ktypes == NULL)
508	ktypes = (char **)(intptr_t)default_keytypes;
509
510
511    ret = 0;
512
513    for(kp = ktypes; kp && *kp; kp++) {
514	const char *p;
515	krb5_salt salt;
516	krb5_enctype *etypes;
517	size_t num_etypes;
518
519	p = *kp;
520	/* check alias */
521	if(strcmp(p, "v5") == 0)
522	    p = "pw-salt";
523	else if(strcmp(p, "v4") == 0)
524	    p = "des:pw-salt:";
525	else if(strcmp(p, "afs") == 0 || strcmp(p, "afs3") == 0)
526	    p = "des:afs3-salt";
527	else if (strcmp(p, "arcfour-hmac-md5") == 0)
528	    p = "arcfour-hmac-md5:pw-salt";
529
530	memset(&salt, 0, sizeof(salt));
531
532	ret = parse_key_set(context, p,
533			    &etypes, &num_etypes, &salt, principal);
534	if (ret) {
535	    krb5_warn(context, ret, "bad value for default_keys `%s'", *kp);
536	    ret = 0;
537	    continue;
538	}
539
540	for (i = 0; i < num_etypes; i++) {
541	    /* find duplicates */
542	    for (j = 0; j < *nkeyset; j++) {
543
544		k = &key_set[j];
545
546		if (k->key.keytype == etypes[i]) {
547		    if (no_salt)
548			break;
549		    if (k->salt == NULL && salt.salttype == KRB5_PW_SALT)
550			break;
551		    if (k->salt->type == salt.salttype &&
552			k->salt->salt.length == salt.saltvalue.length &&
553			memcmp(k->salt->salt.data, salt.saltvalue.data,
554			       salt.saltvalue.length) == 0)
555			break;
556		}
557	    }
558	    /* not a duplicate, lets add it */
559	    if (j == *nkeyset) {
560		ret = add_enctype_to_key_set(&key_set, nkeyset, etypes[i],
561					     no_salt ? NULL : &salt);
562		if (ret) {
563		    free(etypes);
564		    krb5_free_salt(context, salt);
565		    goto out;
566		}
567	    }
568	}
569	free(etypes);
570	krb5_free_salt(context, salt);
571    }
572
573    *ret_key_set = key_set;
574
575 out:
576    if (ktypes != (char **)(intptr_t)default_keytypes)
577	krb5_config_free_strings(ktypes);
578
579    if (ret) {
580	krb5_warn(context, ret,
581		  "failed to parse the [kadmin]default_keys values");
582
583	for (i = 0; i < *nkeyset; i++)
584	    free_Key(&key_set[i]);
585	free(key_set);
586    } else if (*nkeyset == 0) {
587	krb5_warnx(context,
588		   "failed to parse any of the [kadmin]default_keys values");
589	ret = EINVAL; /* XXX */
590    }
591
592    return ret;
593}
594
595
596krb5_error_code
597hdb_generate_key_set_password(krb5_context context,
598			      krb5_principal principal,
599			      const char *password,
600			      int n_ks_tuple, krb5_key_salt_tuple *ks_tuple,
601			      Key **keys, size_t *num_keys)
602{
603    krb5_error_code ret;
604    size_t i;
605
606    *keys = NULL;
607    *num_keys = 0;
608
609    ret = hdb_generate_key_set(context, principal, n_ks_tuple, ks_tuple,
610				keys, num_keys, 0);
611    if (ret)
612	return ret;
613
614    for (i = 0; i < (*num_keys); i++) {
615	krb5_salt salt;
616
617	if ((*keys)[i].salt) {
618	    salt.salttype = (*keys)[i].salt->type;
619	    salt.saltvalue.length = (*keys)[i].salt->salt.length;
620	    salt.saltvalue.data = (*keys)[i].salt->salt.data;
621	} else {
622	    memset(&salt, 0, sizeof(salt));
623	}
624
625	ret = krb5_string_to_key_salt (context,
626				       (*keys)[i].key.keytype,
627				       password,
628				       salt,
629				       &(*keys)[i].key);
630
631	if(ret)
632	    break;
633    }
634
635    if(ret) {
636	hdb_free_keys (context, *num_keys, *keys);
637	return ret;
638    }
639    return ret;
640}
641