1/*
2 * Copyright (c) 1999 - 2002 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
36/* keytab backend for HDB databases */
37
38struct hdb_data {
39    char *dbname;
40    char *mkey;
41};
42
43struct hdb_cursor {
44    HDB *db;
45    hdb_entry_ex hdb_entry;
46    int first, next;
47    int key_idx;
48};
49
50/*
51 * the format for HDB keytabs is:
52 * HDB:[HDBFORMAT:database-specific-data[:mkey=mkey-file]]
53 */
54
55static krb5_error_code KRB5_CALLCONV
56hdb_resolve(krb5_context context, const char *name, krb5_keytab id)
57{
58    struct hdb_data *d;
59    const char *db, *mkey;
60
61    d = malloc(sizeof(*d));
62    if(d == NULL) {
63	krb5_set_error_message(context, ENOMEM, "malloc: out of memory");
64	return ENOMEM;
65    }
66    db = name;
67    mkey = strstr(name, ":mkey=");
68    if(mkey == NULL || mkey[5] == '\0') {
69	if(*name == '\0')
70	    d->dbname = NULL;
71	else {
72	    d->dbname = strdup(name);
73	    if(d->dbname == NULL) {
74		free(d);
75		krb5_set_error_message(context, ENOMEM, "malloc: out of memory");
76		return ENOMEM;
77	    }
78	}
79	d->mkey = NULL;
80    } else {
81	d->dbname = malloc(mkey - db + 1);
82	if(d->dbname == NULL) {
83	    free(d);
84	    krb5_set_error_message(context, ENOMEM, "malloc: out of memory");
85	    return ENOMEM;
86	}
87	memmove(d->dbname, db, mkey - db);
88	d->dbname[mkey - db] = '\0';
89
90	d->mkey = strdup(mkey + 5);
91	if(d->mkey == NULL) {
92	    free(d->dbname);
93	    free(d);
94	    krb5_set_error_message(context, ENOMEM, "malloc: out of memory");
95	    return ENOMEM;
96	}
97    }
98    id->data = d;
99    return 0;
100}
101
102static krb5_error_code KRB5_CALLCONV
103hdb_close(krb5_context context, krb5_keytab id)
104{
105    struct hdb_data *d = id->data;
106
107    free(d->dbname);
108    free(d->mkey);
109    free(d);
110    return 0;
111}
112
113static krb5_error_code KRB5_CALLCONV
114hdb_get_name(krb5_context context,
115	     krb5_keytab id,
116	     char *name,
117	     size_t namesize)
118{
119    struct hdb_data *d = id->data;
120
121    snprintf(name, namesize, "%s%s%s",
122	     d->dbname ? d->dbname : "",
123	     (d->dbname || d->mkey) ? ":" : "",
124	     d->mkey ? d->mkey : "");
125    return 0;
126}
127
128/*
129 * try to figure out the database (`dbname') and master-key (`mkey')
130 * that should be used for `principal'.
131 */
132
133static krb5_error_code
134find_db (krb5_context context,
135	 char **dbname,
136	 char **mkey,
137	 krb5_const_principal principal)
138{
139    krb5_const_realm realm = krb5_principal_get_realm(context, principal);
140    krb5_error_code ret;
141    struct hdb_dbinfo *head, *dbinfo = NULL;
142
143    *dbname = *mkey = NULL;
144
145    ret = hdb_get_dbinfo(context, &head);
146    if (ret)
147	return ret;
148
149    while ((dbinfo = hdb_dbinfo_get_next(head, dbinfo)) != NULL) {
150	const char *p = hdb_dbinfo_get_realm(context, dbinfo);
151	if (p && strcmp (realm, p) == 0) {
152	    p = hdb_dbinfo_get_dbname(context, dbinfo);
153	    if (p)
154		*dbname = strdup(p);
155	    p = hdb_dbinfo_get_mkey_file(context, dbinfo);
156	    if (p)
157		*mkey = strdup(p);
158	    break;
159	}
160    }
161    hdb_free_dbinfo(context, &head);
162    if (*dbname == NULL)
163	*dbname = strdup(HDB_DEFAULT_DB);
164    return 0;
165}
166
167/*
168 * find the keytab entry in `id' for `principal, kvno, enctype' and return
169 * it in `entry'.  return 0 or an error code
170 */
171
172static krb5_error_code KRB5_CALLCONV
173hdb_get_entry(krb5_context context,
174	      krb5_keytab id,
175	      krb5_const_principal principal,
176	      krb5_kvno kvno,
177	      krb5_enctype enctype,
178	      krb5_keytab_entry *entry)
179{
180    hdb_entry_ex ent;
181    krb5_error_code ret;
182    struct hdb_data *d = id->data;
183    const char *dbname = d->dbname;
184    const char *mkey   = d->mkey;
185    char *fdbname = NULL, *fmkey = NULL;
186    HDB *db;
187    size_t i;
188
189    memset(&ent, 0, sizeof(ent));
190
191    if (dbname == NULL) {
192	ret = find_db(context, &fdbname, &fmkey, principal);
193	if (ret)
194	    return ret;
195	dbname = fdbname;
196	mkey = fmkey;
197    }
198
199    ret = hdb_create (context, &db, dbname);
200    if (ret)
201	goto out2;
202    ret = hdb_set_master_keyfile (context, db, mkey);
203    if (ret) {
204	(*db->hdb_destroy)(context, db);
205	goto out2;
206    }
207
208    ret = (*db->hdb_open)(context, db, O_RDONLY, 0);
209    if (ret) {
210	(*db->hdb_destroy)(context, db);
211	goto out2;
212    }
213
214    ret = (*db->hdb_fetch_kvno)(context, db, principal,
215				HDB_F_DECRYPT|HDB_F_KVNO_SPECIFIED|
216				HDB_F_GET_CLIENT|HDB_F_GET_SERVER|HDB_F_GET_KRBTGT,
217				kvno, &ent);
218
219    if(ret == HDB_ERR_NOENTRY) {
220	ret = KRB5_KT_NOTFOUND;
221	goto out;
222    }else if(ret)
223	goto out;
224
225    if(kvno && (krb5_kvno)ent.entry.kvno != kvno) {
226	hdb_free_entry(context, &ent);
227 	ret = KRB5_KT_NOTFOUND;
228	goto out;
229    }
230    if(enctype == 0)
231	if(ent.entry.keys.len > 0)
232	    enctype = ent.entry.keys.val[0].key.keytype;
233    ret = KRB5_KT_NOTFOUND;
234    for(i = 0; i < ent.entry.keys.len; i++) {
235	if(ent.entry.keys.val[i].key.keytype == enctype) {
236	    krb5_copy_principal(context, principal, &entry->principal);
237	    entry->vno = ent.entry.kvno;
238	    krb5_copy_keyblock_contents(context,
239					&ent.entry.keys.val[i].key,
240					&entry->keyblock);
241	    ret = 0;
242	    break;
243	}
244    }
245    hdb_free_entry(context, &ent);
246 out:
247    (*db->hdb_close)(context, db);
248    (*db->hdb_destroy)(context, db);
249 out2:
250    free(fdbname);
251    free(fmkey);
252    return ret;
253}
254
255/*
256 * find the keytab entry in `id' for `principal, kvno, enctype' and return
257 * it in `entry'.  return 0 or an error code
258 */
259
260static krb5_error_code KRB5_CALLCONV
261hdb_start_seq_get(krb5_context context,
262		  krb5_keytab id,
263		  krb5_kt_cursor *cursor)
264{
265    krb5_error_code ret;
266    struct hdb_cursor *c;
267    struct hdb_data *d = id->data;
268    const char *dbname = d->dbname;
269    const char *mkey   = d->mkey;
270    HDB *db;
271
272    if (dbname == NULL) {
273	/*
274	 * We don't support enumerating without being told what
275	 * backend to enumerate on
276	 */
277  	ret = KRB5_KT_NOTFOUND;
278	return ret;
279    }
280
281    ret = hdb_create (context, &db, dbname);
282    if (ret)
283	return ret;
284    ret = hdb_set_master_keyfile (context, db, mkey);
285    if (ret) {
286	(*db->hdb_destroy)(context, db);
287	return ret;
288    }
289
290    ret = (*db->hdb_open)(context, db, O_RDONLY, 0);
291    if (ret) {
292	(*db->hdb_destroy)(context, db);
293	return ret;
294    }
295
296    cursor->data = c = malloc (sizeof(*c));
297    if(c == NULL){
298	(*db->hdb_close)(context, db);
299	(*db->hdb_destroy)(context, db);
300	krb5_set_error_message(context, ENOMEM, "malloc: out of memory");
301	return ENOMEM;
302    }
303
304    c->db = db;
305    c->first = TRUE;
306    c->next = TRUE;
307    c->key_idx = 0;
308
309    cursor->data = c;
310    return ret;
311}
312
313static int KRB5_CALLCONV
314hdb_next_entry(krb5_context context,
315	       krb5_keytab id,
316	       krb5_keytab_entry *entry,
317	       krb5_kt_cursor *cursor)
318{
319    struct hdb_cursor *c = cursor->data;
320    krb5_error_code ret;
321
322    memset(entry, 0, sizeof(*entry));
323
324    if (c->first) {
325	c->first = FALSE;
326	ret = (c->db->hdb_firstkey)(context, c->db,
327				    HDB_F_DECRYPT|
328				    HDB_F_GET_CLIENT|HDB_F_GET_SERVER|HDB_F_GET_KRBTGT,
329				    &c->hdb_entry);
330	if (ret == HDB_ERR_NOENTRY)
331	    return KRB5_KT_END;
332	else if (ret)
333	    return ret;
334
335	if (c->hdb_entry.entry.keys.len == 0)
336	    hdb_free_entry(context, &c->hdb_entry);
337	else
338	    c->next = FALSE;
339    }
340
341    while (c->next) {
342	ret = (c->db->hdb_nextkey)(context, c->db,
343				   HDB_F_DECRYPT|
344				   HDB_F_GET_CLIENT|HDB_F_GET_SERVER|HDB_F_GET_KRBTGT,
345				   &c->hdb_entry);
346	if (ret == HDB_ERR_NOENTRY)
347	    return KRB5_KT_END;
348	else if (ret)
349	    return ret;
350
351	/* If no keys on this entry, try again */
352	if (c->hdb_entry.entry.keys.len == 0)
353	    hdb_free_entry(context, &c->hdb_entry);
354	else
355	    c->next = FALSE;
356    }
357
358    /*
359     * Return next enc type (keytabs are one slot per key, while
360     * hdb is one record per principal.
361     */
362
363    ret = krb5_copy_principal(context,
364			      c->hdb_entry.entry.principal,
365			      &entry->principal);
366    if (ret)
367	return ret;
368
369    entry->vno = c->hdb_entry.entry.kvno;
370    ret = krb5_copy_keyblock_contents(context,
371				      &c->hdb_entry.entry.keys.val[c->key_idx].key,
372				      &entry->keyblock);
373    if (ret) {
374	krb5_free_principal(context, entry->principal);
375	memset(entry, 0, sizeof(*entry));
376	return ret;
377    }
378    c->key_idx++;
379
380    /*
381     * Once we get to the end of the list, signal that we want the
382     * next entry
383     */
384
385    if ((size_t)c->key_idx == c->hdb_entry.entry.keys.len) {
386	hdb_free_entry(context, &c->hdb_entry);
387	c->next = TRUE;
388	c->key_idx = 0;
389    }
390
391    return 0;
392}
393
394
395static int KRB5_CALLCONV
396hdb_end_seq_get(krb5_context context,
397		krb5_keytab id,
398		krb5_kt_cursor *cursor)
399{
400    struct hdb_cursor *c = cursor->data;
401
402    if (!c->next)
403	hdb_free_entry(context, &c->hdb_entry);
404
405    (c->db->hdb_close)(context, c->db);
406    (c->db->hdb_destroy)(context, c->db);
407
408    free(c);
409    return 0;
410}
411
412krb5_kt_ops hdb_kt_ops = {
413    "HDB",
414    hdb_resolve,
415    hdb_get_name,
416    hdb_close,
417    NULL,		/* destroy */
418    hdb_get_entry,
419    hdb_start_seq_get,
420    hdb_next_entry,
421    hdb_end_seq_get,
422    NULL,		/* add */
423    NULL		/* remove */
424};
425