1/*	$NetBSD$	*/
2
3/*
4 * Copyright (c) 1997 - 2001, 2003 Kungliga Tekniska H��gskolan
5 * (Royal Institute of Technology, Stockholm, Sweden).
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 *
12 * 1. Redistributions of source code must retain the above copyright
13 *    notice, this list of conditions and the following disclaimer.
14 *
15 * 2. Redistributions in binary form must reproduce the above copyright
16 *    notice, this list of conditions and the following disclaimer in the
17 *    documentation and/or other materials provided with the distribution.
18 *
19 * 3. Neither the name of the Institute nor the names of its contributors
20 *    may be used to endorse or promote products derived from this software
21 *    without specific prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * SUCH DAMAGE.
34 */
35
36#include "krb5_locl.h"
37
38/* this is an attempt at one of the most horrible `compression'
39   schemes that has ever been invented; it's so amazingly brain-dead
40   that words can not describe it, and all this just to save a few
41   silly bytes */
42
43struct tr_realm {
44    char *realm;
45    unsigned leading_space:1;
46    unsigned leading_slash:1;
47    unsigned trailing_dot:1;
48    struct tr_realm *next;
49};
50
51static void
52free_realms(struct tr_realm *r)
53{
54    struct tr_realm *p;
55    while(r){
56	p = r;
57	r = r->next;
58	free(p->realm);
59	free(p);
60    }
61}
62
63static int
64make_path(krb5_context context, struct tr_realm *r,
65	  const char *from, const char *to)
66{
67    struct tr_realm *tmp;
68    const char *p;
69
70    if(strlen(from) < strlen(to)){
71	const char *str;
72	str = from;
73	from = to;
74	to = str;
75    }
76
77    if(strcmp(from + strlen(from) - strlen(to), to) == 0){
78	p = from;
79	while(1){
80	    p = strchr(p, '.');
81	    if(p == NULL) {
82		krb5_clear_error_message (context);
83		return KRB5KDC_ERR_POLICY;
84	    }
85	    p++;
86	    if(strcmp(p, to) == 0)
87		break;
88	    tmp = calloc(1, sizeof(*tmp));
89	    if(tmp == NULL){
90		krb5_set_error_message(context, ENOMEM,
91				       N_("malloc: out of memory", ""));
92		return ENOMEM;
93	    }
94	    tmp->next = r->next;
95	    r->next = tmp;
96	    tmp->realm = strdup(p);
97	    if(tmp->realm == NULL){
98		r->next = tmp->next;
99		free(tmp);
100		krb5_set_error_message(context, ENOMEM,
101				       N_("malloc: out of memory", ""));
102		return ENOMEM;;
103	    }
104	}
105    }else if(strncmp(from, to, strlen(to)) == 0){
106	p = from + strlen(from);
107	while(1){
108	    while(p >= from && *p != '/') p--;
109	    if(p == from)
110		return KRB5KDC_ERR_POLICY;
111
112	    if(strncmp(to, from, p - from) == 0)
113		break;
114	    tmp = calloc(1, sizeof(*tmp));
115	    if(tmp == NULL){
116		krb5_set_error_message(context, ENOMEM,
117				       N_("malloc: out of memory", ""));
118		return ENOMEM;
119	    }
120	    tmp->next = r->next;
121	    r->next = tmp;
122	    tmp->realm = malloc(p - from + 1);
123	    if(tmp->realm == NULL){
124		r->next = tmp->next;
125		free(tmp);
126		krb5_set_error_message(context, ENOMEM,
127				       N_("malloc: out of memory", ""));
128		return ENOMEM;
129	    }
130	    memcpy(tmp->realm, from, p - from);
131	    tmp->realm[p - from] = '\0';
132	    p--;
133	}
134    } else {
135	krb5_clear_error_message (context);
136	return KRB5KDC_ERR_POLICY;
137    }
138
139    return 0;
140}
141
142static int
143make_paths(krb5_context context,
144	   struct tr_realm *realms, const char *client_realm,
145	   const char *server_realm)
146{
147    struct tr_realm *r;
148    int ret;
149    const char *prev_realm = client_realm;
150    const char *next_realm = NULL;
151    for(r = realms; r; r = r->next){
152	/* it *might* be that you can have more than one empty
153	   component in a row, at least that's how I interpret the
154	   "," exception in 1510 */
155	if(r->realm[0] == '\0'){
156	    while(r->next && r->next->realm[0] == '\0')
157		r = r->next;
158	    if(r->next)
159		next_realm = r->next->realm;
160	    else
161		next_realm = server_realm;
162	    ret = make_path(context, r, prev_realm, next_realm);
163	    if(ret){
164		free_realms(realms);
165		return ret;
166	    }
167	}
168	prev_realm = r->realm;
169    }
170    return 0;
171}
172
173static int
174expand_realms(krb5_context context,
175	      struct tr_realm *realms, const char *client_realm)
176{
177    struct tr_realm *r;
178    const char *prev_realm = NULL;
179    for(r = realms; r; r = r->next){
180	if(r->trailing_dot){
181	    char *tmp;
182	    size_t len;
183
184	    if(prev_realm == NULL)
185		prev_realm = client_realm;
186
187	    len = strlen(r->realm) + strlen(prev_realm) + 1;
188
189	    tmp = realloc(r->realm, len);
190	    if(tmp == NULL){
191		free_realms(realms);
192		krb5_set_error_message(context, ENOMEM,
193				       N_("malloc: out of memory", ""));
194		return ENOMEM;
195	    }
196	    r->realm = tmp;
197	    strlcat(r->realm, prev_realm, len);
198	}else if(r->leading_slash && !r->leading_space && prev_realm){
199	    /* yet another exception: if you use x500-names, the
200               leading realm doesn't have to be "quoted" with a space */
201	    char *tmp;
202	    size_t len = strlen(r->realm) + strlen(prev_realm) + 1;
203
204	    tmp = malloc(len);
205	    if(tmp == NULL){
206		free_realms(realms);
207		krb5_set_error_message(context, ENOMEM,
208				       N_("malloc: out of memory", ""));
209		return ENOMEM;
210	    }
211	    strlcpy(tmp, prev_realm, len);
212	    strlcat(tmp, r->realm, len);
213	    free(r->realm);
214	    r->realm = tmp;
215	}
216	prev_realm = r->realm;
217    }
218    return 0;
219}
220
221static struct tr_realm *
222make_realm(char *realm)
223{
224    struct tr_realm *r;
225    char *p, *q;
226    int quote = 0;
227    r = calloc(1, sizeof(*r));
228    if(r == NULL){
229	free(realm);
230	return NULL;
231    }
232    r->realm = realm;
233    for(p = q = r->realm; *p; p++){
234	if(p == r->realm && *p == ' '){
235	    r->leading_space = 1;
236	    continue;
237	}
238	if(q == r->realm && *p == '/')
239	    r->leading_slash = 1;
240	if(quote){
241	    *q++ = *p;
242	    quote = 0;
243	    continue;
244	}
245	if(*p == '\\'){
246	    quote = 1;
247	    continue;
248	}
249	if(p[0] == '.' && p[1] == '\0')
250	    r->trailing_dot = 1;
251	*q++ = *p;
252    }
253    *q = '\0';
254    return r;
255}
256
257static struct tr_realm*
258append_realm(struct tr_realm *head, struct tr_realm *r)
259{
260    struct tr_realm *p;
261    if(head == NULL){
262	r->next = NULL;
263	return r;
264    }
265    p = head;
266    while(p->next) p = p->next;
267    p->next = r;
268    return head;
269}
270
271static int
272decode_realms(krb5_context context,
273	      const char *tr, int length, struct tr_realm **realms)
274{
275    struct tr_realm *r = NULL;
276
277    char *tmp;
278    int quote = 0;
279    const char *start = tr;
280    int i;
281
282    for(i = 0; i < length; i++){
283	if(quote){
284	    quote = 0;
285	    continue;
286	}
287	if(tr[i] == '\\'){
288	    quote = 1;
289	    continue;
290	}
291	if(tr[i] == ','){
292	    tmp = malloc(tr + i - start + 1);
293	    if(tmp == NULL){
294		krb5_set_error_message(context, ENOMEM,
295				       N_("malloc: out of memory", ""));
296		return ENOMEM;
297	    }
298	    memcpy(tmp, start, tr + i - start);
299	    tmp[tr + i - start] = '\0';
300	    r = make_realm(tmp);
301	    if(r == NULL){
302		free_realms(*realms);
303		krb5_set_error_message(context, ENOMEM,
304				       N_("malloc: out of memory", ""));
305		return ENOMEM;
306	    }
307	    *realms = append_realm(*realms, r);
308	    start = tr + i + 1;
309	}
310    }
311    tmp = malloc(tr + i - start + 1);
312    if(tmp == NULL){
313	free(*realms);
314	krb5_set_error_message(context, ENOMEM,
315			       N_("malloc: out of memory", ""));
316	return ENOMEM;
317    }
318    memcpy(tmp, start, tr + i - start);
319    tmp[tr + i - start] = '\0';
320    r = make_realm(tmp);
321    if(r == NULL){
322	free_realms(*realms);
323	krb5_set_error_message(context, ENOMEM,
324			       N_("malloc: out of memory", ""));
325	return ENOMEM;
326    }
327    *realms = append_realm(*realms, r);
328
329    return 0;
330}
331
332
333KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
334krb5_domain_x500_decode(krb5_context context,
335			krb5_data tr, char ***realms, unsigned int *num_realms,
336			const char *client_realm, const char *server_realm)
337{
338    struct tr_realm *r = NULL;
339    struct tr_realm *p, **q;
340    int ret;
341
342    if(tr.length == 0) {
343	*realms = NULL;
344	*num_realms = 0;
345	return 0;
346    }
347
348    /* split string in components */
349    ret = decode_realms(context, tr.data, tr.length, &r);
350    if(ret)
351	return ret;
352
353    /* apply prefix rule */
354    ret = expand_realms(context, r, client_realm);
355    if(ret)
356	return ret;
357
358    ret = make_paths(context, r, client_realm, server_realm);
359    if(ret)
360	return ret;
361
362    /* remove empty components and count realms */
363    *num_realms = 0;
364    for(q = &r; *q; ){
365	if((*q)->realm[0] == '\0'){
366	    p = *q;
367	    *q = (*q)->next;
368	    free(p->realm);
369	    free(p);
370	}else{
371	    q = &(*q)->next;
372	    (*num_realms)++;
373	}
374    }
375    if (*num_realms < 0 || *num_realms + 1 > UINT_MAX/sizeof(**realms))
376	return ERANGE;
377
378    {
379	char **R;
380	R = malloc((*num_realms + 1) * sizeof(*R));
381	if (R == NULL)
382	    return ENOMEM;
383	*realms = R;
384	while(r){
385	    *R++ = r->realm;
386	    p = r->next;
387	    free(r);
388	    r = p;
389	}
390    }
391    return 0;
392}
393
394KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
395krb5_domain_x500_encode(char **realms, unsigned int num_realms,
396			krb5_data *encoding)
397{
398    char *s = NULL;
399    int len = 0;
400    unsigned int i;
401    krb5_data_zero(encoding);
402    if (num_realms == 0)
403	return 0;
404    for(i = 0; i < num_realms; i++){
405	len += strlen(realms[i]);
406	if(realms[i][0] == '/')
407	    len++;
408    }
409    len += num_realms - 1;
410    s = malloc(len + 1);
411    if (s == NULL)
412	return ENOMEM;
413    *s = '\0';
414    for(i = 0; i < num_realms; i++){
415	if(i && i < num_realms - 1)
416	    strlcat(s, ",", len + 1);
417	if(realms[i][0] == '/')
418	    strlcat(s, " ", len + 1);
419	strlcat(s, realms[i], len + 1);
420    }
421    encoding->data = s;
422    encoding->length = strlen(s);
423    return 0;
424}
425
426KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
427krb5_check_transited(krb5_context context,
428		     krb5_const_realm client_realm,
429		     krb5_const_realm server_realm,
430		     krb5_realm *realms,
431		     unsigned int num_realms,
432		     int *bad_realm)
433{
434    char **tr_realms;
435    char **p;
436    int i;
437
438    if(num_realms == 0)
439	return 0;
440
441    tr_realms = krb5_config_get_strings(context, NULL,
442					"capaths",
443					client_realm,
444					server_realm,
445					NULL);
446    for(i = 0; i < num_realms; i++) {
447	for(p = tr_realms; p && *p; p++) {
448	    if(strcmp(*p, realms[i]) == 0)
449		break;
450	}
451	if(p == NULL || *p == NULL) {
452	    krb5_config_free_strings(tr_realms);
453	    krb5_set_error_message (context, KRB5KRB_AP_ERR_ILL_CR_TKT,
454				    N_("no transit allowed "
455				       "through realm %s", ""),
456				    realms[i]);
457	    if(bad_realm)
458		*bad_realm = i;
459	    return KRB5KRB_AP_ERR_ILL_CR_TKT;
460	}
461    }
462    krb5_config_free_strings(tr_realms);
463    return 0;
464}
465
466KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
467krb5_check_transited_realms(krb5_context context,
468			    const char *const *realms,
469			    unsigned int num_realms,
470			    int *bad_realm)
471{
472    int i;
473    int ret = 0;
474    char **bad_realms = krb5_config_get_strings(context, NULL,
475						"libdefaults",
476						"transited_realms_reject",
477						NULL);
478    if(bad_realms == NULL)
479	return 0;
480
481    for(i = 0; i < num_realms; i++) {
482	char **p;
483	for(p = bad_realms; *p; p++)
484	    if(strcmp(*p, realms[i]) == 0) {
485		ret = KRB5KRB_AP_ERR_ILL_CR_TKT;
486		krb5_set_error_message (context, ret,
487					N_("no transit allowed "
488					   "through realm %s", ""),
489					*p);
490		if(bad_realm)
491		    *bad_realm = i;
492		break;
493	    }
494    }
495    krb5_config_free_strings(bad_realms);
496    return ret;
497}
498
499#if 0
500int
501main(int argc, char **argv)
502{
503    krb5_data x;
504    char **r;
505    int num, i;
506    x.data = argv[1];
507    x.length = strlen(x.data);
508    if(domain_expand(x, &r, &num, argv[2], argv[3]))
509	exit(1);
510    for(i = 0; i < num; i++)
511	printf("%s\n", r[i]);
512    return 0;
513}
514#endif
515
516