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
36RCSID("$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
43krb5_error_code KRB5_LIB_FUNCTION
44krb5_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
73krb5_error_code KRB5_LIB_FUNCTION
74krb5_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
126krb5_error_code KRB5_LIB_FUNCTION
127krb5_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
141krb5_error_code KRB5_LIB_FUNCTION
142krb5_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
172krb5_error_code KRB5_LIB_FUNCTION
173krb5_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
184krb5_error_code KRB5_LIB_FUNCTION
185krb5_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
218krb5_error_code KRB5_LIB_FUNCTION
219krb5_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
233krb5_error_code KRB5_LIB_FUNCTION
234krb5_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
248krb5_error_code KRB5_LIB_FUNCTION
249krb5_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
281krb5_error_code KRB5_LIB_FUNCTION
282krb5_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
299krb5_boolean KRB5_LIB_FUNCTION
300krb5_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
323krb5_error_code KRB5_LIB_FUNCTION
324krb5_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
395krb5_error_code KRB5_LIB_FUNCTION
396krb5_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;
415fail:
416    krb5_kt_free_entry (context, out);
417    return ret;
418}
419
420/*
421 * Free the contents of `entry'.
422 */
423
424krb5_error_code KRB5_LIB_FUNCTION
425krb5_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
439krb5_error_code KRB5_LIB_FUNCTION
440krb5_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
459krb5_error_code KRB5_LIB_FUNCTION
460krb5_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
478krb5_error_code KRB5_LIB_FUNCTION
479krb5_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
497krb5_error_code KRB5_LIB_FUNCTION
498krb5_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
516krb5_error_code KRB5_LIB_FUNCTION
517krb5_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