1 /*
2 * Copyright (c) 1997 - 2001, 2003 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 "krb5_locl.h"
35
36 /* this is an attempt at one of the most horrible `compression'
37 schemes that has ever been invented; it's so amazingly brain-dead
38 that words can not describe it, and all this just to save a few
39 silly bytes */
40
41 struct tr_realm {
42 char *realm;
43 unsigned leading_space:1;
44 unsigned leading_slash:1;
45 unsigned trailing_dot:1;
46 struct tr_realm *next;
47 };
48
49 static void
free_realms(struct tr_realm * r)50 free_realms(struct tr_realm *r)
51 {
52 struct tr_realm *p;
53 while(r){
54 p = r;
55 r = r->next;
56 free(p->realm);
57 free(p);
58 }
59 }
60
61 static int
make_path(krb5_context context,struct tr_realm * r,const char * from,const char * to)62 make_path(krb5_context context, struct tr_realm *r,
63 const char *from, const char *to)
64 {
65 struct tr_realm *tmp;
66 const char *p;
67
68 if(strlen(from) < strlen(to)){
69 const char *str;
70 str = from;
71 from = to;
72 to = str;
73 }
74
75 if(strcmp(from + strlen(from) - strlen(to), to) == 0){
76 p = from;
77 while(1){
78 p = strchr(p, '.');
79 if(p == NULL) {
80 krb5_clear_error_message (context);
81 return KRB5KDC_ERR_POLICY;
82 }
83 p++;
84 if(strcmp(p, to) == 0)
85 break;
86 tmp = calloc(1, sizeof(*tmp));
87 if(tmp == NULL)
88 return krb5_enomem(context);
89 tmp->next = r->next;
90 r->next = tmp;
91 tmp->realm = strdup(p);
92 if(tmp->realm == NULL){
93 r->next = tmp->next;
94 free(tmp);
95 return krb5_enomem(context);
96 }
97 }
98 }else if(strncmp(from, to, strlen(to)) == 0){
99 p = from + strlen(from);
100 while(1){
101 while(p >= from && *p != '/') p--;
102 if(p == from)
103 return KRB5KDC_ERR_POLICY;
104
105 if(strncmp(to, from, p - from) == 0)
106 break;
107 tmp = calloc(1, sizeof(*tmp));
108 if(tmp == NULL)
109 return krb5_enomem(context);
110 tmp->next = r->next;
111 r->next = tmp;
112 tmp->realm = malloc(p - from + 1);
113 if(tmp->realm == NULL){
114 r->next = tmp->next;
115 free(tmp);
116 return krb5_enomem(context);
117 }
118 memcpy(tmp->realm, from, p - from);
119 tmp->realm[p - from] = '\0';
120 p--;
121 }
122 } else {
123 krb5_clear_error_message (context);
124 return KRB5KDC_ERR_POLICY;
125 }
126
127 return 0;
128 }
129
130 static int
make_paths(krb5_context context,struct tr_realm * realms,const char * client_realm,const char * server_realm)131 make_paths(krb5_context context,
132 struct tr_realm *realms, const char *client_realm,
133 const char *server_realm)
134 {
135 struct tr_realm *r;
136 int ret;
137 const char *prev_realm = client_realm;
138 const char *next_realm = NULL;
139 for(r = realms; r; r = r->next){
140 /* it *might* be that you can have more than one empty
141 component in a row, at least that's how I interpret the
142 "," exception in 1510 */
143 if(r->realm[0] == '\0'){
144 while(r->next && r->next->realm[0] == '\0')
145 r = r->next;
146 if(r->next)
147 next_realm = r->next->realm;
148 else
149 next_realm = server_realm;
150 ret = make_path(context, r, prev_realm, next_realm);
151 if(ret){
152 free_realms(realms);
153 return ret;
154 }
155 }
156 prev_realm = r->realm;
157 }
158 return 0;
159 }
160
161 static int
expand_realms(krb5_context context,struct tr_realm * realms,const char * client_realm)162 expand_realms(krb5_context context,
163 struct tr_realm *realms, const char *client_realm)
164 {
165 struct tr_realm *r;
166 const char *prev_realm = NULL;
167 for(r = realms; r; r = r->next){
168 if(r->trailing_dot){
169 char *tmp;
170 size_t len;
171
172 if(prev_realm == NULL)
173 prev_realm = client_realm;
174
175 len = strlen(r->realm) + strlen(prev_realm) + 1;
176
177 tmp = realloc(r->realm, len);
178 if(tmp == NULL){
179 free_realms(realms);
180 return krb5_enomem(context);
181 }
182 r->realm = tmp;
183 strlcat(r->realm, prev_realm, len);
184 }else if(r->leading_slash && !r->leading_space && prev_realm){
185 /* yet another exception: if you use x500-names, the
186 leading realm doesn't have to be "quoted" with a space */
187 char *tmp;
188 size_t len = strlen(r->realm) + strlen(prev_realm) + 1;
189
190 tmp = malloc(len);
191 if(tmp == NULL){
192 free_realms(realms);
193 return krb5_enomem(context);
194 }
195 strlcpy(tmp, prev_realm, len);
196 strlcat(tmp, r->realm, len);
197 free(r->realm);
198 r->realm = tmp;
199 }
200 prev_realm = r->realm;
201 }
202 return 0;
203 }
204
205 static struct tr_realm *
make_realm(char * realm)206 make_realm(char *realm)
207 {
208 struct tr_realm *r;
209 char *p, *q;
210 int quote = 0;
211 r = calloc(1, sizeof(*r));
212 if(r == NULL){
213 free(realm);
214 return NULL;
215 }
216 r->realm = realm;
217 for(p = q = r->realm; *p; p++){
218 if(p == r->realm && *p == ' '){
219 r->leading_space = 1;
220 continue;
221 }
222 if(q == r->realm && *p == '/')
223 r->leading_slash = 1;
224 if(quote){
225 *q++ = *p;
226 quote = 0;
227 continue;
228 }
229 if(*p == '\\'){
230 quote = 1;
231 continue;
232 }
233 if(p[0] == '.' && p[1] == '\0')
234 r->trailing_dot = 1;
235 *q++ = *p;
236 }
237 *q = '\0';
238 return r;
239 }
240
241 static struct tr_realm*
append_realm(struct tr_realm * head,struct tr_realm * r)242 append_realm(struct tr_realm *head, struct tr_realm *r)
243 {
244 struct tr_realm *p;
245 if(head == NULL){
246 r->next = NULL;
247 return r;
248 }
249 p = head;
250 while(p->next) p = p->next;
251 p->next = r;
252 return head;
253 }
254
255 static int
decode_realms(krb5_context context,const char * tr,int length,struct tr_realm ** realms)256 decode_realms(krb5_context context,
257 const char *tr, int length, struct tr_realm **realms)
258 {
259 struct tr_realm *r = NULL;
260
261 char *tmp;
262 int quote = 0;
263 const char *start = tr;
264 int i;
265
266 for(i = 0; i < length; i++){
267 if(quote){
268 quote = 0;
269 continue;
270 }
271 if(tr[i] == '\\'){
272 quote = 1;
273 continue;
274 }
275 if(tr[i] == ','){
276 tmp = malloc(tr + i - start + 1);
277 if(tmp == NULL)
278 return krb5_enomem(context);
279 memcpy(tmp, start, tr + i - start);
280 tmp[tr + i - start] = '\0';
281 r = make_realm(tmp);
282 if(r == NULL){
283 free_realms(*realms);
284 *realms = NULL;
285 return krb5_enomem(context);
286 }
287 *realms = append_realm(*realms, r);
288 start = tr + i + 1;
289 }
290 }
291 tmp = malloc(tr + i - start + 1);
292 if(tmp == NULL){
293 free_realms(*realms);
294 *realms = NULL;
295 return krb5_enomem(context);
296 }
297 memcpy(tmp, start, tr + i - start);
298 tmp[tr + i - start] = '\0';
299 r = make_realm(tmp);
300 if(r == NULL){
301 free_realms(*realms);
302 *realms = NULL;
303 return krb5_enomem(context);
304 }
305 *realms = append_realm(*realms, r);
306
307 return 0;
308 }
309
310
311 KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
krb5_domain_x500_decode(krb5_context context,krb5_data tr,char *** realms,unsigned int * num_realms,const char * client_realm,const char * server_realm)312 krb5_domain_x500_decode(krb5_context context,
313 krb5_data tr, char ***realms, unsigned int *num_realms,
314 const char *client_realm, const char *server_realm)
315 {
316 struct tr_realm *r = NULL;
317 struct tr_realm *p, **q;
318 int ret;
319
320 if(tr.length == 0) {
321 *realms = NULL;
322 *num_realms = 0;
323 return 0;
324 }
325
326 /* split string in components */
327 ret = decode_realms(context, tr.data, tr.length, &r);
328 if(ret)
329 return ret;
330
331 /* apply prefix rule */
332 ret = expand_realms(context, r, client_realm);
333 if(ret)
334 return ret;
335
336 ret = make_paths(context, r, client_realm, server_realm);
337 if(ret)
338 return ret;
339
340 /* remove empty components and count realms */
341 *num_realms = 0;
342 for(q = &r; *q; ){
343 if((*q)->realm[0] == '\0'){
344 p = *q;
345 *q = (*q)->next;
346 free(p->realm);
347 free(p);
348 }else{
349 q = &(*q)->next;
350 (*num_realms)++;
351 }
352 }
353 if (*num_realms + 1 > UINT_MAX/sizeof(**realms))
354 return ERANGE;
355
356 {
357 char **R;
358 R = malloc((*num_realms + 1) * sizeof(*R));
359 if (R == NULL)
360 return krb5_enomem(context);
361 *realms = R;
362 while(r){
363 *R++ = r->realm;
364 p = r->next;
365 free(r);
366 r = p;
367 }
368 }
369 return 0;
370 }
371
372 KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
krb5_domain_x500_encode(char ** realms,unsigned int num_realms,krb5_data * encoding)373 krb5_domain_x500_encode(char **realms, unsigned int num_realms,
374 krb5_data *encoding)
375 {
376 char *s = NULL;
377 int len = 0;
378 unsigned int i;
379 krb5_data_zero(encoding);
380 if (num_realms == 0)
381 return 0;
382 for(i = 0; i < num_realms; i++){
383 len += strlen(realms[i]);
384 if(realms[i][0] == '/')
385 len++;
386 }
387 len += num_realms - 1;
388 s = malloc(len + 1);
389 if (s == NULL)
390 return ENOMEM;
391 *s = '\0';
392 for(i = 0; i < num_realms; i++){
393 if(i)
394 strlcat(s, ",", len + 1);
395 if(realms[i][0] == '/')
396 strlcat(s, " ", len + 1);
397 strlcat(s, realms[i], len + 1);
398 }
399 encoding->data = s;
400 encoding->length = strlen(s);
401 return 0;
402 }
403
404 KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
krb5_check_transited(krb5_context context,krb5_const_realm client_realm,krb5_const_realm server_realm,krb5_realm * realms,unsigned int num_realms,int * bad_realm)405 krb5_check_transited(krb5_context context,
406 krb5_const_realm client_realm,
407 krb5_const_realm server_realm,
408 krb5_realm *realms,
409 unsigned int num_realms,
410 int *bad_realm)
411 {
412 char **tr_realms;
413 char **p;
414 size_t i;
415
416 if(num_realms == 0)
417 return 0;
418
419 tr_realms = krb5_config_get_strings(context, NULL,
420 "capaths",
421 client_realm,
422 server_realm,
423 NULL);
424 for(i = 0; i < num_realms; i++) {
425 for(p = tr_realms; p && *p; p++) {
426 if(strcmp(*p, realms[i]) == 0)
427 break;
428 }
429 if(p == NULL || *p == NULL) {
430 krb5_config_free_strings(tr_realms);
431 krb5_set_error_message (context, KRB5KRB_AP_ERR_ILL_CR_TKT,
432 N_("no transit allowed "
433 "through realm %s", ""),
434 realms[i]);
435 if(bad_realm)
436 *bad_realm = i;
437 return KRB5KRB_AP_ERR_ILL_CR_TKT;
438 }
439 }
440 krb5_config_free_strings(tr_realms);
441 return 0;
442 }
443
444 KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
krb5_check_transited_realms(krb5_context context,const char * const * realms,unsigned int num_realms,int * bad_realm)445 krb5_check_transited_realms(krb5_context context,
446 const char *const *realms,
447 unsigned int num_realms,
448 int *bad_realm)
449 {
450 size_t i;
451 int ret = 0;
452 char **bad_realms = krb5_config_get_strings(context, NULL,
453 "libdefaults",
454 "transited_realms_reject",
455 NULL);
456 if(bad_realms == NULL)
457 return 0;
458
459 for(i = 0; i < num_realms; i++) {
460 char **p;
461 for(p = bad_realms; *p; p++)
462 if(strcmp(*p, realms[i]) == 0) {
463 ret = KRB5KRB_AP_ERR_ILL_CR_TKT;
464 krb5_set_error_message (context, ret,
465 N_("no transit allowed "
466 "through realm %s", ""),
467 *p);
468 if(bad_realm)
469 *bad_realm = i;
470 break;
471 }
472 }
473 krb5_config_free_strings(bad_realms);
474 return ret;
475 }
476
477 #if 0
478 int
479 main(int argc, char **argv)
480 {
481 krb5_data x;
482 char **r;
483 int num, i;
484 x.data = argv[1];
485 x.length = strlen(x.data);
486 if(domain_expand(x, &r, &num, argv[2], argv[3]))
487 exit(1);
488 for(i = 0; i < num; i++)
489 printf("%s\n", r[i]);
490 return 0;
491 }
492 #endif
493
494