transited.c
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 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 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 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 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 * 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* 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 256 decode_realms(krb5_context context, 257 const char *tr, size_t 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 size_t 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 return krb5_enomem(context); 285 } 286 *realms = append_realm(*realms, r); 287 start = tr + i + 1; 288 } 289 } 290 tmp = malloc(tr + i - start + 1); 291 if(tmp == NULL){ 292 free(*realms); 293 return krb5_enomem(context); 294 } 295 memcpy(tmp, start, tr + i - start); 296 tmp[tr + i - start] = '\0'; 297 r = make_realm(tmp); 298 if(r == NULL){ 299 free_realms(*realms); 300 return krb5_enomem(context); 301 } 302 *realms = append_realm(*realms, r); 303 304 return 0; 305 } 306 307 308 KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL 309 krb5_domain_x500_decode(krb5_context context, 310 krb5_data tr, char ***realms, unsigned int *num_realms, 311 const char *client_realm, const char *server_realm) 312 { 313 struct tr_realm *r = NULL; 314 struct tr_realm *p, **q; 315 int ret; 316 317 if(tr.length == 0) { 318 *realms = NULL; 319 *num_realms = 0; 320 return 0; 321 } 322 323 /* split string in components */ 324 ret = decode_realms(context, tr.data, tr.length, &r); 325 if(ret) 326 return ret; 327 328 /* apply prefix rule */ 329 ret = expand_realms(context, r, client_realm); 330 if(ret) 331 return ret; 332 333 ret = make_paths(context, r, client_realm, server_realm); 334 if(ret) 335 return ret; 336 337 /* remove empty components and count realms */ 338 *num_realms = 0; 339 for(q = &r; *q; ){ 340 if((*q)->realm[0] == '\0'){ 341 p = *q; 342 *q = (*q)->next; 343 free(p->realm); 344 free(p); 345 }else{ 346 q = &(*q)->next; 347 (*num_realms)++; 348 } 349 } 350 if (*num_realms + 1 > UINT_MAX/sizeof(**realms)) 351 return ERANGE; 352 353 { 354 char **R; 355 R = malloc((*num_realms + 1) * sizeof(*R)); 356 if (R == NULL) 357 return krb5_enomem(context); 358 *realms = R; 359 while(r){ 360 *R++ = r->realm; 361 p = r->next; 362 free(r); 363 r = p; 364 } 365 } 366 return 0; 367 } 368 369 KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL 370 krb5_domain_x500_encode(char **realms, unsigned int num_realms, 371 krb5_data *encoding) 372 { 373 char *s = NULL; 374 int len = 0; 375 unsigned int i; 376 krb5_data_zero(encoding); 377 if (num_realms == 0) 378 return 0; 379 for(i = 0; i < num_realms; i++){ 380 len += strlen(realms[i]); 381 if(realms[i][0] == '/') 382 len++; 383 } 384 len += num_realms - 1; 385 s = malloc(len + 1); 386 if (s == NULL) 387 return ENOMEM; 388 *s = '\0'; 389 for(i = 0; i < num_realms; i++){ 390 if(i) 391 strlcat(s, ",", len + 1); 392 if(realms[i][0] == '/') 393 strlcat(s, " ", len + 1); 394 strlcat(s, realms[i], len + 1); 395 } 396 encoding->data = s; 397 encoding->length = strlen(s); 398 return 0; 399 } 400 401 KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL 402 krb5_check_transited(krb5_context context, 403 krb5_const_realm client_realm, 404 krb5_const_realm server_realm, 405 krb5_realm *realms, 406 unsigned int num_realms, 407 int *bad_realm) 408 { 409 char **tr_realms; 410 char **p; 411 size_t i; 412 413 if(num_realms == 0) 414 return 0; 415 416 tr_realms = krb5_config_get_strings(context, NULL, 417 "capaths", 418 client_realm, 419 server_realm, 420 NULL); 421 for(i = 0; i < num_realms; i++) { 422 for(p = tr_realms; p && *p; p++) { 423 if(strcmp(*p, realms[i]) == 0) 424 break; 425 } 426 if(p == NULL || *p == NULL) { 427 krb5_config_free_strings(tr_realms); 428 krb5_set_error_message (context, KRB5KRB_AP_ERR_ILL_CR_TKT, 429 N_("no transit allowed " 430 "through realm %s", ""), 431 realms[i]); 432 if(bad_realm) 433 *bad_realm = (int)i; 434 return KRB5KRB_AP_ERR_ILL_CR_TKT; 435 } 436 } 437 krb5_config_free_strings(tr_realms); 438 return 0; 439 } 440 441 KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL 442 krb5_check_transited_realms(krb5_context context, 443 const char *const *realms, 444 unsigned int num_realms, 445 int *bad_realm) 446 { 447 size_t i; 448 int ret = 0; 449 char **bad_realms = krb5_config_get_strings(context, NULL, 450 "libdefaults", 451 "transited_realms_reject", 452 NULL); 453 if(bad_realms == NULL) 454 return 0; 455 456 for(i = 0; i < num_realms; i++) { 457 char **p; 458 for(p = bad_realms; *p; p++) 459 if(strcmp(*p, realms[i]) == 0) { 460 ret = KRB5KRB_AP_ERR_ILL_CR_TKT; 461 krb5_set_error_message (context, ret, 462 N_("no transit allowed " 463 "through realm %s", ""), 464 *p); 465 if(bad_realm) 466 *bad_realm = (int)i; 467 break; 468 } 469 } 470 krb5_config_free_strings(bad_realms); 471 return ret; 472 } 473 474 #if 0 475 int 476 main(int argc, char **argv) 477 { 478 krb5_data x; 479 char **r; 480 int num, i; 481 x.data = argv[1]; 482 x.length = strlen(x.data); 483 if(domain_expand(x, &r, &num, argv[2], argv[3])) 484 exit(1); 485 for(i = 0; i < num; i++) 486 printf("%s\n", r[i]); 487 return 0; 488 } 489 #endif 490