keytab.c revision 102644
1/*
2 * Copyright (c) 1997 - 2002 Kungliga Tekniska H�gskolan
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 "krb5_locl.h"
35
36RCSID("$Id: keytab.c,v 1.53 2002/03/10 23:14:12 assar Exp $");
37
38/*
39 * Register a new keytab in `ops'
40 * Return 0 or an error.
41 */
42
43krb5_error_code
44krb5_kt_register(krb5_context context,
45		 const krb5_kt_ops *ops)
46{
47    struct krb5_keytab_data *tmp;
48
49    tmp = realloc(context->kt_types,
50		  (context->num_kt_types + 1) * sizeof(*context->kt_types));
51    if(tmp == NULL) {
52	krb5_set_error_string(context, "malloc: out of memory");
53	return ENOMEM;
54    }
55    memcpy(&tmp[context->num_kt_types], ops,
56	   sizeof(tmp[context->num_kt_types]));
57    context->kt_types = tmp;
58    context->num_kt_types++;
59    return 0;
60}
61
62/*
63 * Resolve the keytab name (of the form `type:residual') in `name'
64 * into a keytab in `id'.
65 * Return 0 or an error
66 */
67
68krb5_error_code
69krb5_kt_resolve(krb5_context context,
70		const char *name,
71		krb5_keytab *id)
72{
73    krb5_keytab k;
74    int i;
75    const char *type, *residual;
76    size_t type_len;
77    krb5_error_code ret;
78
79    residual = strchr(name, ':');
80    if(residual == NULL) {
81	type = "FILE";
82	type_len = strlen(type);
83	residual = name;
84    } else {
85	type = name;
86	type_len = residual - name;
87	residual++;
88    }
89
90    for(i = 0; i < context->num_kt_types; i++) {
91	if(strncasecmp(type, context->kt_types[i].prefix, type_len) == 0)
92	    break;
93    }
94    if(i == context->num_kt_types) {
95	krb5_set_error_string(context, "unknown keytab type %.*s",
96			      (int)type_len, type);
97	return KRB5_KT_UNKNOWN_TYPE;
98    }
99
100    k = malloc (sizeof(*k));
101    if (k == NULL) {
102	krb5_set_error_string(context, "malloc: out of memory");
103	return ENOMEM;
104    }
105    memcpy(k, &context->kt_types[i], sizeof(*k));
106    k->data = NULL;
107    ret = (*k->resolve)(context, residual, k);
108    if(ret) {
109	free(k);
110	k = NULL;
111    }
112    *id = k;
113    return ret;
114}
115
116/*
117 * copy the name of the default keytab into `name'.
118 * Return 0 or KRB5_CONFIG_NOTENUFSPACE if `namesize' is too short.
119 */
120
121krb5_error_code
122krb5_kt_default_name(krb5_context context, char *name, size_t namesize)
123{
124    if (strlcpy (name, context->default_keytab, namesize) >= namesize) {
125	krb5_clear_error_string (context);
126	return KRB5_CONFIG_NOTENUFSPACE;
127    }
128    return 0;
129}
130
131/*
132 * copy the name of the default modify keytab into `name'.
133 * Return 0 or KRB5_CONFIG_NOTENUFSPACE if `namesize' is too short.
134 */
135
136krb5_error_code
137krb5_kt_default_modify_name(krb5_context context, char *name, size_t namesize)
138{
139    const char *kt = NULL;
140    if(context->default_keytab_modify == NULL) {
141	if(strncasecmp(context->default_keytab, "ANY:", 4) != 0)
142	    kt = context->default_keytab;
143	else {
144	    size_t len = strcspn(context->default_keytab + 4, ",");
145	    if(len >= namesize) {
146		krb5_clear_error_string(context);
147		return KRB5_CONFIG_NOTENUFSPACE;
148	    }
149	    strlcpy(name, context->default_keytab + 4, namesize);
150	    name[len] = '\0';
151	    return 0;
152	}
153    } else
154	kt = context->default_keytab_modify;
155    if (strlcpy (name, kt, namesize) >= namesize) {
156	krb5_clear_error_string (context);
157	return KRB5_CONFIG_NOTENUFSPACE;
158    }
159    return 0;
160}
161
162/*
163 * Set `id' to the default keytab.
164 * Return 0 or an error.
165 */
166
167krb5_error_code
168krb5_kt_default(krb5_context context, krb5_keytab *id)
169{
170    return krb5_kt_resolve (context, context->default_keytab, id);
171}
172
173/*
174 * Read the key identified by `(principal, vno, enctype)' from the
175 * keytab in `keyprocarg' (the default if == NULL) into `*key'.
176 * Return 0 or an error.
177 */
178
179krb5_error_code
180krb5_kt_read_service_key(krb5_context context,
181			 krb5_pointer keyprocarg,
182			 krb5_principal principal,
183			 krb5_kvno vno,
184			 krb5_enctype enctype,
185			 krb5_keyblock **key)
186{
187    krb5_keytab keytab;
188    krb5_keytab_entry entry;
189    krb5_error_code ret;
190
191    if (keyprocarg)
192	ret = krb5_kt_resolve (context, keyprocarg, &keytab);
193    else
194	ret = krb5_kt_default (context, &keytab);
195
196    if (ret)
197	return ret;
198
199    ret = krb5_kt_get_entry (context, keytab, principal, vno, enctype, &entry);
200    krb5_kt_close (context, keytab);
201    if (ret)
202	return ret;
203    ret = krb5_copy_keyblock (context, &entry.keyblock, key);
204    krb5_kt_free_entry(context, &entry);
205    return ret;
206}
207
208/*
209 * Retrieve the name of the keytab `keytab' into `name', `namesize'
210 * Return 0 or an error.
211 */
212
213krb5_error_code
214krb5_kt_get_name(krb5_context context,
215		 krb5_keytab keytab,
216		 char *name,
217		 size_t namesize)
218{
219    return (*keytab->get_name)(context, keytab, name, namesize);
220}
221
222/*
223 * Finish using the keytab in `id'.  All resources will be released.
224 * Return 0 or an error.
225 */
226
227krb5_error_code
228krb5_kt_close(krb5_context context,
229	      krb5_keytab id)
230{
231    krb5_error_code ret;
232
233    ret = (*id->close)(context, id);
234    if(ret == 0)
235	free(id);
236    return ret;
237}
238
239/*
240 * Compare `entry' against `principal, vno, enctype'.
241 * Any of `principal, vno, enctype' might be 0 which acts as a wildcard.
242 * Return TRUE if they compare the same, FALSE otherwise.
243 */
244
245krb5_boolean
246krb5_kt_compare(krb5_context context,
247		krb5_keytab_entry *entry,
248		krb5_const_principal principal,
249		krb5_kvno vno,
250		krb5_enctype enctype)
251{
252    if(principal != NULL &&
253       !krb5_principal_compare(context, entry->principal, principal))
254	return FALSE;
255    if(vno && vno != entry->vno)
256	return FALSE;
257    if(enctype && enctype != entry->keyblock.keytype)
258	return FALSE;
259    return TRUE;
260}
261
262/*
263 * Retrieve the keytab entry for `principal, kvno, enctype' into `entry'
264 * from the keytab `id'.
265 * kvno == 0 is a wildcard and gives the keytab with the highest vno.
266 * Return 0 or an error.
267 */
268
269krb5_error_code
270krb5_kt_get_entry(krb5_context context,
271		  krb5_keytab id,
272		  krb5_const_principal principal,
273		  krb5_kvno kvno,
274		  krb5_enctype enctype,
275		  krb5_keytab_entry *entry)
276{
277    krb5_keytab_entry tmp;
278    krb5_error_code ret;
279    krb5_kt_cursor cursor;
280
281    if(id->get)
282	return (*id->get)(context, id, principal, kvno, enctype, entry);
283
284    ret = krb5_kt_start_seq_get (context, id, &cursor);
285    if (ret)
286	return KRB5_KT_NOTFOUND; /* XXX i.e. file not found */
287
288    entry->vno = 0;
289    while (krb5_kt_next_entry(context, id, &tmp, &cursor) == 0) {
290	if (krb5_kt_compare(context, &tmp, principal, 0, enctype)) {
291	    /* the file keytab might only store the lower 8 bits of
292	       the kvno, so only compare those bits */
293	    if (kvno == tmp.vno
294		|| (tmp.vno < 256 && kvno % 256 == tmp.vno)) {
295		krb5_kt_copy_entry_contents (context, &tmp, entry);
296		krb5_kt_free_entry (context, &tmp);
297		krb5_kt_end_seq_get(context, id, &cursor);
298		return 0;
299	    } else if (kvno == 0 && tmp.vno > entry->vno) {
300		if (entry->vno)
301		    krb5_kt_free_entry (context, entry);
302		krb5_kt_copy_entry_contents (context, &tmp, entry);
303	    }
304	}
305	krb5_kt_free_entry(context, &tmp);
306    }
307    krb5_kt_end_seq_get (context, id, &cursor);
308    if (entry->vno) {
309	return 0;
310    } else {
311	char princ[256], kt_name[256];
312
313	krb5_unparse_name_fixed (context, principal, princ, sizeof(princ));
314	krb5_kt_get_name (context, id, kt_name, sizeof(kt_name));
315
316	krb5_set_error_string (context,
317 			       "failed to find %s%s%d%s in keytab %s",
318			       princ,
319			       kvno ? "(" : "",
320			       kvno,
321			       kvno ? ")" : "",
322			       kt_name);
323	return KRB5_KT_NOTFOUND;
324    }
325}
326
327/*
328 * Copy the contents of `in' into `out'.
329 * Return 0 or an error.  */
330
331krb5_error_code
332krb5_kt_copy_entry_contents(krb5_context context,
333			    const krb5_keytab_entry *in,
334			    krb5_keytab_entry *out)
335{
336    krb5_error_code ret;
337
338    memset(out, 0, sizeof(*out));
339    out->vno = in->vno;
340
341    ret = krb5_copy_principal (context, in->principal, &out->principal);
342    if (ret)
343	goto fail;
344    ret = krb5_copy_keyblock_contents (context,
345				       &in->keyblock,
346				       &out->keyblock);
347    if (ret)
348	goto fail;
349    out->timestamp = in->timestamp;
350    return 0;
351fail:
352    krb5_kt_free_entry (context, out);
353    return ret;
354}
355
356/*
357 * Free the contents of `entry'.
358 */
359
360krb5_error_code
361krb5_kt_free_entry(krb5_context context,
362		   krb5_keytab_entry *entry)
363{
364  krb5_free_principal (context, entry->principal);
365  krb5_free_keyblock_contents (context, &entry->keyblock);
366  return 0;
367}
368
369#if 0
370static int
371xxxlock(int fd, int write)
372{
373    if(flock(fd, (write ? LOCK_EX : LOCK_SH) | LOCK_NB) < 0) {
374	sleep(1);
375	if(flock(fd, (write ? LOCK_EX : LOCK_SH) | LOCK_NB) < 0)
376	    return -1;
377    }
378    return 0;
379}
380
381static void
382xxxunlock(int fd)
383{
384    flock(fd, LOCK_UN);
385}
386#endif
387
388/*
389 * Set `cursor' to point at the beginning of `id'.
390 * Return 0 or an error.
391 */
392
393krb5_error_code
394krb5_kt_start_seq_get(krb5_context context,
395		      krb5_keytab id,
396		      krb5_kt_cursor *cursor)
397{
398    if(id->start_seq_get == NULL) {
399	krb5_set_error_string(context,
400			      "start_seq_get is not supported in the %s "
401			      " keytab", id->prefix);
402	return HEIM_ERR_OPNOTSUPP;
403    }
404    return (*id->start_seq_get)(context, id, cursor);
405}
406
407/*
408 * Get the next entry from `id' pointed to by `cursor' and advance the
409 * `cursor'.
410 * Return 0 or an error.
411 */
412
413krb5_error_code
414krb5_kt_next_entry(krb5_context context,
415		   krb5_keytab id,
416		   krb5_keytab_entry *entry,
417		   krb5_kt_cursor *cursor)
418{
419    if(id->next_entry == NULL) {
420	krb5_set_error_string(context,
421			      "next_entry is not supported in the %s "
422			      " keytab", id->prefix);
423	return HEIM_ERR_OPNOTSUPP;
424    }
425    return (*id->next_entry)(context, id, entry, cursor);
426}
427
428/*
429 * Release all resources associated with `cursor'.
430 */
431
432krb5_error_code
433krb5_kt_end_seq_get(krb5_context context,
434		    krb5_keytab id,
435		    krb5_kt_cursor *cursor)
436{
437    if(id->end_seq_get == NULL) {
438	krb5_set_error_string(context,
439			      "end_seq_get is not supported in the %s "
440			      " keytab", id->prefix);
441	return HEIM_ERR_OPNOTSUPP;
442    }
443    return (*id->end_seq_get)(context, id, cursor);
444}
445
446/*
447 * Add the entry in `entry' to the keytab `id'.
448 * Return 0 or an error.
449 */
450
451krb5_error_code
452krb5_kt_add_entry(krb5_context context,
453		  krb5_keytab id,
454		  krb5_keytab_entry *entry)
455{
456    if(id->add == NULL) {
457	krb5_set_error_string(context, "Add is not supported in the %s keytab",
458			      id->prefix);
459	return KRB5_KT_NOWRITE;
460    }
461    entry->timestamp = time(NULL);
462    return (*id->add)(context, id,entry);
463}
464
465/*
466 * Remove the entry `entry' from the keytab `id'.
467 * Return 0 or an error.
468 */
469
470krb5_error_code
471krb5_kt_remove_entry(krb5_context context,
472		     krb5_keytab id,
473		     krb5_keytab_entry *entry)
474{
475    if(id->remove == NULL) {
476	krb5_set_error_string(context,
477			      "Remove is not supported in the %s keytab",
478			      id->prefix);
479	return KRB5_KT_NOWRITE;
480    }
481    return (*id->remove)(context, id, entry);
482}
483