xref: /freebsd/crypto/heimdal/lib/hdb/keytab.c (revision 77c1fcec914bae1232762ca0b0462abd6957ff26)
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 
38 struct hdb_data {
39     char *dbname;
40     char *mkey;
41 };
42 
43 struct 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 
55 static krb5_error_code KRB5_CALLCONV
56 hdb_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 
102 static krb5_error_code KRB5_CALLCONV
103 hdb_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 
113 static krb5_error_code KRB5_CALLCONV
114 hdb_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 
133 static krb5_error_code
134 find_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 
172 static krb5_error_code KRB5_CALLCONV
173 hdb_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 
260 static krb5_error_code KRB5_CALLCONV
261 hdb_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 
313 static int KRB5_CALLCONV
314 hdb_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 
395 static int KRB5_CALLCONV
396 hdb_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 
412 krb5_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