xref: /freebsd/crypto/heimdal/lib/krb5/keytab.c (revision 39beb93c)
1 /*
2  * Copyright (c) 1997 - 2005 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 
36 RCSID("$Id: keytab.c 20211 2007-02-09 07:11:03Z lha $");
37 
38 /*
39  * Register a new keytab in `ops'
40  * Return 0 or an error.
41  */
42 
43 krb5_error_code KRB5_LIB_FUNCTION
44 krb5_kt_register(krb5_context context,
45 		 const krb5_kt_ops *ops)
46 {
47     struct krb5_keytab_data *tmp;
48 
49     if (strlen(ops->prefix) > KRB5_KT_PREFIX_MAX_LEN - 1) {
50 	krb5_set_error_string(context, "krb5_kt_register; prefix too long");
51 	return KRB5_KT_BADNAME;
52     }
53 
54     tmp = realloc(context->kt_types,
55 		  (context->num_kt_types + 1) * sizeof(*context->kt_types));
56     if(tmp == NULL) {
57 	krb5_set_error_string(context, "malloc: out of memory");
58 	return ENOMEM;
59     }
60     memcpy(&tmp[context->num_kt_types], ops,
61 	   sizeof(tmp[context->num_kt_types]));
62     context->kt_types = tmp;
63     context->num_kt_types++;
64     return 0;
65 }
66 
67 /*
68  * Resolve the keytab name (of the form `type:residual') in `name'
69  * into a keytab in `id'.
70  * Return 0 or an error
71  */
72 
73 krb5_error_code KRB5_LIB_FUNCTION
74 krb5_kt_resolve(krb5_context context,
75 		const char *name,
76 		krb5_keytab *id)
77 {
78     krb5_keytab k;
79     int i;
80     const char *type, *residual;
81     size_t type_len;
82     krb5_error_code ret;
83 
84     residual = strchr(name, ':');
85     if(residual == NULL) {
86 	type = "FILE";
87 	type_len = strlen(type);
88 	residual = name;
89     } else {
90 	type = name;
91 	type_len = residual - name;
92 	residual++;
93     }
94 
95     for(i = 0; i < context->num_kt_types; i++) {
96 	if(strncasecmp(type, context->kt_types[i].prefix, type_len) == 0)
97 	    break;
98     }
99     if(i == context->num_kt_types) {
100 	krb5_set_error_string(context, "unknown keytab type %.*s",
101 			      (int)type_len, type);
102 	return KRB5_KT_UNKNOWN_TYPE;
103     }
104 
105     k = malloc (sizeof(*k));
106     if (k == NULL) {
107 	krb5_set_error_string(context, "malloc: out of memory");
108 	return ENOMEM;
109     }
110     memcpy(k, &context->kt_types[i], sizeof(*k));
111     k->data = NULL;
112     ret = (*k->resolve)(context, residual, k);
113     if(ret) {
114 	free(k);
115 	k = NULL;
116     }
117     *id = k;
118     return ret;
119 }
120 
121 /*
122  * copy the name of the default keytab into `name'.
123  * Return 0 or KRB5_CONFIG_NOTENUFSPACE if `namesize' is too short.
124  */
125 
126 krb5_error_code KRB5_LIB_FUNCTION
127 krb5_kt_default_name(krb5_context context, char *name, size_t namesize)
128 {
129     if (strlcpy (name, context->default_keytab, namesize) >= namesize) {
130 	krb5_clear_error_string (context);
131 	return KRB5_CONFIG_NOTENUFSPACE;
132     }
133     return 0;
134 }
135 
136 /*
137  * copy the name of the default modify keytab into `name'.
138  * Return 0 or KRB5_CONFIG_NOTENUFSPACE if `namesize' is too short.
139  */
140 
141 krb5_error_code KRB5_LIB_FUNCTION
142 krb5_kt_default_modify_name(krb5_context context, char *name, size_t namesize)
143 {
144     const char *kt = NULL;
145     if(context->default_keytab_modify == NULL) {
146 	if(strncasecmp(context->default_keytab, "ANY:", 4) != 0)
147 	    kt = context->default_keytab;
148 	else {
149 	    size_t len = strcspn(context->default_keytab + 4, ",");
150 	    if(len >= namesize) {
151 		krb5_clear_error_string(context);
152 		return KRB5_CONFIG_NOTENUFSPACE;
153 	    }
154 	    strlcpy(name, context->default_keytab + 4, namesize);
155 	    name[len] = '\0';
156 	    return 0;
157 	}
158     } else
159 	kt = context->default_keytab_modify;
160     if (strlcpy (name, kt, namesize) >= namesize) {
161 	krb5_clear_error_string (context);
162 	return KRB5_CONFIG_NOTENUFSPACE;
163     }
164     return 0;
165 }
166 
167 /*
168  * Set `id' to the default keytab.
169  * Return 0 or an error.
170  */
171 
172 krb5_error_code KRB5_LIB_FUNCTION
173 krb5_kt_default(krb5_context context, krb5_keytab *id)
174 {
175     return krb5_kt_resolve (context, context->default_keytab, id);
176 }
177 
178 /*
179  * Read the key identified by `(principal, vno, enctype)' from the
180  * keytab in `keyprocarg' (the default if == NULL) into `*key'.
181  * Return 0 or an error.
182  */
183 
184 krb5_error_code KRB5_LIB_FUNCTION
185 krb5_kt_read_service_key(krb5_context context,
186 			 krb5_pointer keyprocarg,
187 			 krb5_principal principal,
188 			 krb5_kvno vno,
189 			 krb5_enctype enctype,
190 			 krb5_keyblock **key)
191 {
192     krb5_keytab keytab;
193     krb5_keytab_entry entry;
194     krb5_error_code ret;
195 
196     if (keyprocarg)
197 	ret = krb5_kt_resolve (context, keyprocarg, &keytab);
198     else
199 	ret = krb5_kt_default (context, &keytab);
200 
201     if (ret)
202 	return ret;
203 
204     ret = krb5_kt_get_entry (context, keytab, principal, vno, enctype, &entry);
205     krb5_kt_close (context, keytab);
206     if (ret)
207 	return ret;
208     ret = krb5_copy_keyblock (context, &entry.keyblock, key);
209     krb5_kt_free_entry(context, &entry);
210     return ret;
211 }
212 
213 /*
214  * Return the type of the `keytab' in the string `prefix of length
215  * `prefixsize'.
216  */
217 
218 krb5_error_code KRB5_LIB_FUNCTION
219 krb5_kt_get_type(krb5_context context,
220 		 krb5_keytab keytab,
221 		 char *prefix,
222 		 size_t prefixsize)
223 {
224     strlcpy(prefix, keytab->prefix, prefixsize);
225     return 0;
226 }
227 
228 /*
229  * Retrieve the name of the keytab `keytab' into `name', `namesize'
230  * Return 0 or an error.
231  */
232 
233 krb5_error_code KRB5_LIB_FUNCTION
234 krb5_kt_get_name(krb5_context context,
235 		 krb5_keytab keytab,
236 		 char *name,
237 		 size_t namesize)
238 {
239     return (*keytab->get_name)(context, keytab, name, namesize);
240 }
241 
242 /*
243  * Retrieve the full name of the keytab `keytab' and store the name in
244  * `str'. `str' needs to be freed by the caller using free(3).
245  * Returns 0 or an error. On error, *str is set to NULL.
246  */
247 
248 krb5_error_code KRB5_LIB_FUNCTION
249 krb5_kt_get_full_name(krb5_context context,
250 		      krb5_keytab keytab,
251 		      char **str)
252 {
253     char type[KRB5_KT_PREFIX_MAX_LEN];
254     char name[MAXPATHLEN];
255     krb5_error_code ret;
256 
257     *str = NULL;
258 
259     ret = krb5_kt_get_type(context, keytab, type, sizeof(type));
260     if (ret)
261 	return ret;
262 
263     ret = krb5_kt_get_name(context, keytab, name, sizeof(name));
264     if (ret)
265 	return ret;
266 
267     if (asprintf(str, "%s:%s", type, name) == -1) {
268 	krb5_set_error_string(context, "malloc - out of memory");
269 	*str = NULL;
270 	return ENOMEM;
271     }
272 
273     return 0;
274 }
275 
276 /*
277  * Finish using the keytab in `id'.  All resources will be released,
278  * even on errors.  Return 0 or an error.
279  */
280 
281 krb5_error_code KRB5_LIB_FUNCTION
282 krb5_kt_close(krb5_context context,
283 	      krb5_keytab id)
284 {
285     krb5_error_code ret;
286 
287     ret = (*id->close)(context, id);
288     memset(id, 0, sizeof(*id));
289     free(id);
290     return ret;
291 }
292 
293 /*
294  * Compare `entry' against `principal, vno, enctype'.
295  * Any of `principal, vno, enctype' might be 0 which acts as a wildcard.
296  * Return TRUE if they compare the same, FALSE otherwise.
297  */
298 
299 krb5_boolean KRB5_LIB_FUNCTION
300 krb5_kt_compare(krb5_context context,
301 		krb5_keytab_entry *entry,
302 		krb5_const_principal principal,
303 		krb5_kvno vno,
304 		krb5_enctype enctype)
305 {
306     if(principal != NULL &&
307        !krb5_principal_compare(context, entry->principal, principal))
308 	return FALSE;
309     if(vno && vno != entry->vno)
310 	return FALSE;
311     if(enctype && enctype != entry->keyblock.keytype)
312 	return FALSE;
313     return TRUE;
314 }
315 
316 /*
317  * Retrieve the keytab entry for `principal, kvno, enctype' into `entry'
318  * from the keytab `id'.
319  * kvno == 0 is a wildcard and gives the keytab with the highest vno.
320  * Return 0 or an error.
321  */
322 
323 krb5_error_code KRB5_LIB_FUNCTION
324 krb5_kt_get_entry(krb5_context context,
325 		  krb5_keytab id,
326 		  krb5_const_principal principal,
327 		  krb5_kvno kvno,
328 		  krb5_enctype enctype,
329 		  krb5_keytab_entry *entry)
330 {
331     krb5_keytab_entry tmp;
332     krb5_error_code ret;
333     krb5_kt_cursor cursor;
334 
335     if(id->get)
336 	return (*id->get)(context, id, principal, kvno, enctype, entry);
337 
338     ret = krb5_kt_start_seq_get (context, id, &cursor);
339     if (ret) {
340 	krb5_clear_error_string(context);
341 	return KRB5_KT_NOTFOUND; /* XXX i.e. file not found */
342     }
343 
344     entry->vno = 0;
345     while (krb5_kt_next_entry(context, id, &tmp, &cursor) == 0) {
346 	if (krb5_kt_compare(context, &tmp, principal, 0, enctype)) {
347 	    /* the file keytab might only store the lower 8 bits of
348 	       the kvno, so only compare those bits */
349 	    if (kvno == tmp.vno
350 		|| (tmp.vno < 256 && kvno % 256 == tmp.vno)) {
351 		krb5_kt_copy_entry_contents (context, &tmp, entry);
352 		krb5_kt_free_entry (context, &tmp);
353 		krb5_kt_end_seq_get(context, id, &cursor);
354 		return 0;
355 	    } else if (kvno == 0 && tmp.vno > entry->vno) {
356 		if (entry->vno)
357 		    krb5_kt_free_entry (context, entry);
358 		krb5_kt_copy_entry_contents (context, &tmp, entry);
359 	    }
360 	}
361 	krb5_kt_free_entry(context, &tmp);
362     }
363     krb5_kt_end_seq_get (context, id, &cursor);
364     if (entry->vno) {
365 	return 0;
366     } else {
367 	char princ[256], kvno_str[25], *kt_name;
368 	char *enctype_str = NULL;
369 
370 	krb5_unparse_name_fixed (context, principal, princ, sizeof(princ));
371 	krb5_kt_get_full_name (context, id, &kt_name);
372 	krb5_enctype_to_string(context, enctype, &enctype_str);
373 
374 	if (kvno)
375 	    snprintf(kvno_str, sizeof(kvno_str), "(kvno %d)", kvno);
376 	else
377 	    kvno_str[0] = '\0';
378 
379 	krb5_set_error_string (context,
380  			       "Failed to find %s%s in keytab %s (%s)",
381 			       princ,
382 			       kvno_str,
383 			       kt_name ? kt_name : "unknown keytab",
384 			       enctype_str ? enctype_str : "unknown enctype");
385 	free(kt_name);
386 	free(enctype_str);
387 	return KRB5_KT_NOTFOUND;
388     }
389 }
390 
391 /*
392  * Copy the contents of `in' into `out'.
393  * Return 0 or an error.  */
394 
395 krb5_error_code KRB5_LIB_FUNCTION
396 krb5_kt_copy_entry_contents(krb5_context context,
397 			    const krb5_keytab_entry *in,
398 			    krb5_keytab_entry *out)
399 {
400     krb5_error_code ret;
401 
402     memset(out, 0, sizeof(*out));
403     out->vno = in->vno;
404 
405     ret = krb5_copy_principal (context, in->principal, &out->principal);
406     if (ret)
407 	goto fail;
408     ret = krb5_copy_keyblock_contents (context,
409 				       &in->keyblock,
410 				       &out->keyblock);
411     if (ret)
412 	goto fail;
413     out->timestamp = in->timestamp;
414     return 0;
415 fail:
416     krb5_kt_free_entry (context, out);
417     return ret;
418 }
419 
420 /*
421  * Free the contents of `entry'.
422  */
423 
424 krb5_error_code KRB5_LIB_FUNCTION
425 krb5_kt_free_entry(krb5_context context,
426 		   krb5_keytab_entry *entry)
427 {
428     krb5_free_principal (context, entry->principal);
429     krb5_free_keyblock_contents (context, &entry->keyblock);
430     memset(entry, 0, sizeof(*entry));
431     return 0;
432 }
433 
434 /*
435  * Set `cursor' to point at the beginning of `id'.
436  * Return 0 or an error.
437  */
438 
439 krb5_error_code KRB5_LIB_FUNCTION
440 krb5_kt_start_seq_get(krb5_context context,
441 		      krb5_keytab id,
442 		      krb5_kt_cursor *cursor)
443 {
444     if(id->start_seq_get == NULL) {
445 	krb5_set_error_string(context,
446 			      "start_seq_get is not supported in the %s "
447 			      " keytab", id->prefix);
448 	return HEIM_ERR_OPNOTSUPP;
449     }
450     return (*id->start_seq_get)(context, id, cursor);
451 }
452 
453 /*
454  * Get the next entry from `id' pointed to by `cursor' and advance the
455  * `cursor'.
456  * Return 0 or an error.
457  */
458 
459 krb5_error_code KRB5_LIB_FUNCTION
460 krb5_kt_next_entry(krb5_context context,
461 		   krb5_keytab id,
462 		   krb5_keytab_entry *entry,
463 		   krb5_kt_cursor *cursor)
464 {
465     if(id->next_entry == NULL) {
466 	krb5_set_error_string(context,
467 			      "next_entry is not supported in the %s "
468 			      " keytab", id->prefix);
469 	return HEIM_ERR_OPNOTSUPP;
470     }
471     return (*id->next_entry)(context, id, entry, cursor);
472 }
473 
474 /*
475  * Release all resources associated with `cursor'.
476  */
477 
478 krb5_error_code KRB5_LIB_FUNCTION
479 krb5_kt_end_seq_get(krb5_context context,
480 		    krb5_keytab id,
481 		    krb5_kt_cursor *cursor)
482 {
483     if(id->end_seq_get == NULL) {
484 	krb5_set_error_string(context,
485 			      "end_seq_get is not supported in the %s "
486 			      " keytab", id->prefix);
487 	return HEIM_ERR_OPNOTSUPP;
488     }
489     return (*id->end_seq_get)(context, id, cursor);
490 }
491 
492 /*
493  * Add the entry in `entry' to the keytab `id'.
494  * Return 0 or an error.
495  */
496 
497 krb5_error_code KRB5_LIB_FUNCTION
498 krb5_kt_add_entry(krb5_context context,
499 		  krb5_keytab id,
500 		  krb5_keytab_entry *entry)
501 {
502     if(id->add == NULL) {
503 	krb5_set_error_string(context, "Add is not supported in the %s keytab",
504 			      id->prefix);
505 	return KRB5_KT_NOWRITE;
506     }
507     entry->timestamp = time(NULL);
508     return (*id->add)(context, id,entry);
509 }
510 
511 /*
512  * Remove the entry `entry' from the keytab `id'.
513  * Return 0 or an error.
514  */
515 
516 krb5_error_code KRB5_LIB_FUNCTION
517 krb5_kt_remove_entry(krb5_context context,
518 		     krb5_keytab id,
519 		     krb5_keytab_entry *entry)
520 {
521     if(id->remove == NULL) {
522 	krb5_set_error_string(context,
523 			      "Remove is not supported in the %s keytab",
524 			      id->prefix);
525 	return KRB5_KT_NOWRITE;
526     }
527     return (*id->remove)(context, id, entry);
528 }
529