openssh/openbsd-compat/getrrsetbyname.c

   1 /* $OpenBSD: getrrsetbyname.c,v 1.7 2003/03/07 07:34:14 itojun Exp $ */
   2
   3 /*
   4  * Copyright (c) 2001 Jakob Schlyter. 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  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  18  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  19  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  20  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  21  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  22  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27  */
  28
  29 /*
  30  * Portions Copyright (c) 1999-2001 Internet Software Consortium.
  31  *
  32  * Permission to use, copy, modify, and distribute this software for any
  33  * purpose with or without fee is hereby granted, provided that the above
  34  * copyright notice and this permission notice appear in all copies.
  35  *
  36  * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM
  37  * DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL
  38  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL
  39  * INTERNET SOFTWARE CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT,
  40  * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING
  41  * FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
  42  * NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
  43  * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  44  */
  45
  46 #include "includes.h"
  47
  48 #if defined(DNS) && !defined(HAVE_GETRRSETBYNAME)
  49
  50 #include "getrrsetbyname.h"
  51
  52 /* #include "thread_private.h" */
  53
  54 #define ANSWER_BUFFER_SIZE 1024*64
  55
  56 struct dns_query {
  57         char                    *name;
  58         u_int16_t               type;
  59         u_int16_t               class;
  60         struct dns_query        *next;
  61 };
  62
  63 struct dns_rr {
  64         char                    *name;
  65         u_int16_t               type;
  66         u_int16_t               class;
  67         u_int16_t               ttl;
  68         u_int16_t               size;
  69         void                    *rdata;
  70         struct dns_rr           *next;
  71 };
  72
  73 struct dns_response {
  74         HEADER                  header;
  75         struct dns_query        *query;
  76         struct dns_rr           *answer;
  77         struct dns_rr           *authority;
  78         struct dns_rr           *additional;
  79 };
  80
  81 static struct dns_response *parse_dns_response(const u_char *, int);
  82 static struct dns_query *parse_dns_qsection(const u_char *, int,
  83     const u_char **, int);
  84 static struct dns_rr *parse_dns_rrsection(const u_char *, int, const u_char **,
  85     int);
  86
  87 static void free_dns_query(struct dns_query *);
  88 static void free_dns_rr(struct dns_rr *);
  89 static void free_dns_response(struct dns_response *);
  90
  91 static int count_dns_rr(struct dns_rr *, u_int16_t, u_int16_t);
  92
  93 /*
  94  * Inline versions of get/put short/long.  Pointer is advanced.
  95  *
  96  * These macros demonstrate the property of C whereby it can be
  97  * portable or it can be elegant but rarely both.
  98  */
  99
 100 #ifndef INT32SZ
 101 # define INT32SZ        4
 102 #endif
 103 #ifndef INT16SZ
 104 # define INT16SZ        2
 105 #endif
 106
 107 #ifndef GETSHORT
 108 #define GETSHORT(s, cp) { \
 109         register u_char *t_cp = (u_char *)(cp); \
 110         (s) = ((u_int16_t)t_cp[0] << 8) \
 111             | ((u_int16_t)t_cp[1]) \
 112             ; \
 113         (cp) += INT16SZ; \
 114 }
 115 #endif
 116
 117 #ifndef GETLONG
 118 #define GETLONG(l, cp) { \
 119         register u_char *t_cp = (u_char *)(cp); \
 120         (l) = ((u_int32_t)t_cp[0] << 24) \
 121             | ((u_int32_t)t_cp[1] << 16) \
 122             | ((u_int32_t)t_cp[2] << 8) \
 123             | ((u_int32_t)t_cp[3]) \
 124             ; \
 125         (cp) += INT32SZ; \
 126 }
 127 #endif
 128
 129 /*
 130  * Routines to insert/extract short/long's.
 131  */
 132
 133 #ifndef HAVE__GETSHORT
 134 static u_int16_t
 135 _getshort(msgp)
 136         register const u_char *msgp;
 137 {
 138         register u_int16_t u;
 139
 140         GETSHORT(u, msgp);
 141         return (u);
 142 }
 143 #endif
 144
 145 #ifndef HAVE__GETLONG
 146 static u_int32_t
 147 _getlong(msgp)
 148         register const u_char *msgp;
 149 {
 150         register u_int32_t u;
 151
 152         GETLONG(u, msgp);
 153         return (u);
 154 }
 155 #endif
 156
 157 int
 158 getrrsetbyname(const char *hostname, unsigned int rdclass,
 159     unsigned int rdtype, unsigned int flags,
 160     struct rrsetinfo **res)
 161 {
 162         struct __res_state *_resp = &_res;
 163         int result;
 164         struct rrsetinfo *rrset = NULL;
 165         struct dns_response *response;
 166         struct dns_rr *rr;
 167         struct rdatainfo *rdata;
 168         int length;
 169         unsigned int index_ans, index_sig;
 170         u_char answer[ANSWER_BUFFER_SIZE];
 171
 172         /* check for invalid class and type */
 173         if (rdclass > 0xffff || rdtype > 0xffff) {
 174                 result = ERRSET_INVAL;
 175                 goto fail;
 176         }
 177
 178         /* don't allow queries of class or type ANY */
 179         if (rdclass == 0xff || rdtype == 0xff) {
 180                 result = ERRSET_INVAL;
 181                 goto fail;
 182         }
 183
 184         /* don't allow flags yet, unimplemented */
 185         if (flags) {
 186                 result = ERRSET_INVAL;
 187                 goto fail;
 188         }
 189
 190         /* initialize resolver */
 191         if ((_resp->options & RES_INIT) == 0 && res_init() == -1) {
 192                 result = ERRSET_FAIL;
 193                 goto fail;
 194         }
 195
 196 #ifdef DEBUG
 197         _resp->options |= RES_DEBUG;
 198 #endif /* DEBUG */
 199
 200 #ifdef RES_USE_DNSSEC
 201         /* turn on DNSSEC if EDNS0 is configured */
 202         if (_resp->options & RES_USE_EDNS0)
 203                 _resp->options |= RES_USE_DNSSEC;
 204 #endif /* RES_USE_DNSEC */
 205
 206         /* make query */
 207         length = res_query(hostname, (signed int) rdclass, (signed int) rdtype,
 208             answer, sizeof(answer));
 209         if (length < 0) {
 210                 switch(h_errno) {
 211                 case HOST_NOT_FOUND:
 212                         result = ERRSET_NONAME;
 213                         goto fail;
 214                 case NO_DATA:
 215                         result = ERRSET_NODATA;
 216                         goto fail;
 217                 default:
 218                         result = ERRSET_FAIL;
 219                         goto fail;
 220                 }
 221         }
 222
 223         /* parse result */
 224         response = parse_dns_response(answer, length);
 225         if (response == NULL) {
 226                 result = ERRSET_FAIL;
 227                 goto fail;
 228         }
 229
 230         if (response->header.qdcount != 1) {
 231                 result = ERRSET_FAIL;
 232                 goto fail;
 233         }
 234
 235         /* initialize rrset */
 236         rrset = calloc(1, sizeof(struct rrsetinfo));
 237         if (rrset == NULL) {
 238                 result = ERRSET_NOMEMORY;
 239                 goto fail;
 240         }
 241         rrset->rri_rdclass = response->query->class;
 242         rrset->rri_rdtype = response->query->type;
 243         rrset->rri_ttl = response->answer->ttl;
 244         rrset->rri_nrdatas = response->header.ancount;
 245
 246 #ifdef HAVE_HEADER_AD
 247         /* check for authenticated data */
 248         if (response->header.ad == 1)
 249                 rrset->rri_flags |= RRSET_VALIDATED;
 250 #endif
 251
 252         /* copy name from answer section */
 253         length = strlen(response->answer->name);
 254         rrset->rri_name = malloc(length + 1);
 255         if (rrset->rri_name == NULL) {
 256                 result = ERRSET_NOMEMORY;
 257                 goto fail;
 258         }
 259         strlcpy(rrset->rri_name, response->answer->name, length + 1);
 260
 261         /* count answers */
 262         rrset->rri_nrdatas = count_dns_rr(response->answer, rrset->rri_rdclass,
 263             rrset->rri_rdtype);
 264         rrset->rri_nsigs = count_dns_rr(response->answer, rrset->rri_rdclass,
 265             T_SIG);
 266
 267         /* allocate memory for answers */
 268         rrset->rri_rdatas = calloc(rrset->rri_nrdatas,
 269             sizeof(struct rdatainfo));
 270         if (rrset->rri_rdatas == NULL) {
 271                 result = ERRSET_NOMEMORY;
 272                 goto fail;
 273         }
 274
 275         /* allocate memory for signatures */
 276         rrset->rri_sigs = calloc(rrset->rri_nsigs, sizeof(struct rdatainfo));
 277         if (rrset->rri_sigs == NULL) {
 278                 result = ERRSET_NOMEMORY;
 279                 goto fail;
 280         }
 281
 282         /* copy answers & signatures */
 283         for (rr = response->answer, index_ans = 0, index_sig = 0;
 284             rr; rr = rr->next) {
 285
 286                 rdata = NULL;
 287
 288                 if (rr->class == rrset->rri_rdclass &&
 289                     rr->type  == rrset->rri_rdtype)
 290                         rdata = &rrset->rri_rdatas[index_ans++];
 291
 292                 if (rr->class == rrset->rri_rdclass &&
 293                     rr->type  == T_SIG)
 294                         rdata = &rrset->rri_sigs[index_sig++];
 295
 296                 if (rdata) {
 297                         rdata->rdi_length = rr->size;
 298                         rdata->rdi_data   = malloc(rr->size);
 299
 300                         if (rdata->rdi_data == NULL) {
 301                                 result = ERRSET_NOMEMORY;
 302                                 goto fail;
 303                         }
 304                         memcpy(rdata->rdi_data, rr->rdata, rr->size);
 305                 }
 306         }
 307
 308         *res = rrset;
 309         return (ERRSET_SUCCESS);
 310
 311 fail:
 312         if (rrset != NULL)
 313                 freerrset(rrset);
 314         return (result);
 315 }
 316
 317 void
 318 freerrset(struct rrsetinfo *rrset)
 319 {
 320         u_int16_t i;
 321
 322         if (rrset == NULL)
 323                 return;
 324
 325         if (rrset->rri_rdatas) {
 326                 for (i = 0; i < rrset->rri_nrdatas; i++) {
 327                         if (rrset->rri_rdatas[i].rdi_data == NULL)
 328                                 break;
 329                         free(rrset->rri_rdatas[i].rdi_data);
 330                 }
 331                 free(rrset->rri_rdatas);
 332         }
 333
 334         if (rrset->rri_sigs) {
 335                 for (i = 0; i < rrset->rri_nsigs; i++) {
 336                         if (rrset->rri_sigs[i].rdi_data == NULL)
 337                                 break;
 338                         free(rrset->rri_sigs[i].rdi_data);
 339                 }
 340                 free(rrset->rri_sigs);
 341         }
 342
 343         if (rrset->rri_name)
 344                 free(rrset->rri_name);
 345         free(rrset);
 346 }
 347
 348 /*
 349  * DNS response parsing routines
 350  */
 351 static struct dns_response *
 352 parse_dns_response(const u_char *answer, int size)
 353 {
 354         struct dns_response *resp;
 355         const u_char *cp;
 356
 357         /* allocate memory for the response */
 358         resp = calloc(1, sizeof(*resp));
 359         if (resp == NULL)
 360                 return (NULL);
 361
 362         /* initialize current pointer */
 363         cp = answer;
 364
 365         /* copy header */
 366         memcpy(&resp->header, cp, HFIXEDSZ);
 367         cp += HFIXEDSZ;
 368
 369         /* fix header byte order */
 370         resp->header.qdcount = ntohs(resp->header.qdcount);
 371         resp->header.ancount = ntohs(resp->header.ancount);
 372         resp->header.nscount = ntohs(resp->header.nscount);
 373         resp->header.arcount = ntohs(resp->header.arcount);
 374
 375         /* there must be at least one query */
 376         if (resp->header.qdcount < 1) {
 377                 free_dns_response(resp);
 378                 return (NULL);
 379         }
 380
 381         /* parse query section */
 382         resp->query = parse_dns_qsection(answer, size, &cp,
 383             resp->header.qdcount);
 384         if (resp->header.qdcount && resp->query == NULL) {
 385                 free_dns_response(resp);
 386                 return (NULL);
 387         }
 388
 389         /* parse answer section */
 390         resp->answer = parse_dns_rrsection(answer, size, &cp,
 391             resp->header.ancount);
 392         if (resp->header.ancount && resp->answer == NULL) {
 393                 free_dns_response(resp);
 394                 return (NULL);
 395         }
 396
 397         /* parse authority section */
 398         resp->authority = parse_dns_rrsection(answer, size, &cp,
 399             resp->header.nscount);
 400         if (resp->header.nscount && resp->authority == NULL) {
 401                 free_dns_response(resp);
 402                 return (NULL);
 403         }
 404
 405         /* parse additional section */
 406         resp->additional = parse_dns_rrsection(answer, size, &cp,
 407             resp->header.arcount);
 408         if (resp->header.arcount && resp->additional == NULL) {
 409                 free_dns_response(resp);
 410                 return (NULL);
 411         }
 412
 413         return (resp);
 414 }
 415
 416 static struct dns_query *
 417 parse_dns_qsection(const u_char *answer, int size, const u_char **cp, int count)
 418 {
 419         struct dns_query *head, *curr, *prev;
 420         int i, length;
 421         char name[MAXDNAME];
 422
 423         for (i = 1, head = NULL, prev = NULL; i <= count; i++, prev = curr) {
 424
 425                 /* allocate and initialize struct */
 426                 curr = calloc(1, sizeof(struct dns_query));
 427                 if (curr == NULL) {
 428                         free_dns_query(head);
 429                         return (NULL);
 430                 }
 431                 if (head == NULL)
 432                         head = curr;
 433                 if (prev != NULL)
 434                         prev->next = curr;
 435
 436                 /* name */
 437                 length = dn_expand(answer, answer + size, *cp, name,
 438                     sizeof(name));
 439                 if (length < 0) {
 440                         free_dns_query(head);
 441                         return (NULL);
 442                 }
 443                 curr->name = strdup(name);
 444                 if (curr->name == NULL) {
 445                         free_dns_query(head);
 446                         return (NULL);
 447                 }
 448                 *cp += length;
 449
 450                 /* type */
 451                 curr->type = _getshort(*cp);
 452                 *cp += INT16SZ;
 453
 454                 /* class */
 455                 curr->class = _getshort(*cp);
 456                 *cp += INT16SZ;
 457         }
 458
 459         return (head);
 460 }
 461
 462 static struct dns_rr *
 463 parse_dns_rrsection(const u_char *answer, int size, const u_char **cp, int count)
 464 {
 465         struct dns_rr *head, *curr, *prev;
 466         int i, length;
 467         char name[MAXDNAME];
 468
 469         for (i = 1, head = NULL, prev = NULL; i <= count; i++, prev = curr) {
 470
 471                 /* allocate and initialize struct */
 472                 curr = calloc(1, sizeof(struct dns_rr));
 473                 if (curr == NULL) {
 474                         free_dns_rr(head);
 475                         return (NULL);
 476                 }
 477                 if (head == NULL)
 478                         head = curr;
 479                 if (prev != NULL)
 480                         prev->next = curr;
 481
 482                 /* name */
 483                 length = dn_expand(answer, answer + size, *cp, name,
 484                     sizeof(name));
 485                 if (length < 0) {
 486                         free_dns_rr(head);
 487                         return (NULL);
 488                 }
 489                 curr->name = strdup(name);
 490                 if (curr->name == NULL) {
 491                         free_dns_rr(head);
 492                         return (NULL);
 493                 }
 494                 *cp += length;
 495
 496                 /* type */
 497                 curr->type = _getshort(*cp);
 498                 *cp += INT16SZ;
 499
 500                 /* class */
 501                 curr->class = _getshort(*cp);
 502                 *cp += INT16SZ;
 503
 504                 /* ttl */
 505                 curr->ttl = _getlong(*cp);
 506                 *cp += INT32SZ;
 507
 508                 /* rdata size */
 509                 curr->size = _getshort(*cp);
 510                 *cp += INT16SZ;
 511
 512                 /* rdata itself */
 513                 curr->rdata = malloc(curr->size);
 514                 if (curr->rdata == NULL) {
 515                         free_dns_rr(head);
 516                         return (NULL);
 517                 }
 518                 memcpy(curr->rdata, *cp, curr->size);
 519                 *cp += curr->size;
 520         }
 521
 522         return (head);
 523 }
 524
 525 static void
 526 free_dns_query(struct dns_query *p)
 527 {
 528         if (p == NULL)
 529                 return;
 530
 531         if (p->name)
 532                 free(p->name);
 533         free_dns_query(p->next);
 534         free(p);
 535 }
 536
 537 static void
 538 free_dns_rr(struct dns_rr *p)
 539 {
 540         if (p == NULL)
 541                 return;
 542
 543         if (p->name)
 544                 free(p->name);
 545         if (p->rdata)
 546                 free(p->rdata);
 547         free_dns_rr(p->next);
 548         free(p);
 549 }
 550
 551 static void
 552 free_dns_response(struct dns_response *p)
 553 {
 554         if (p == NULL)
 555                 return;
 556
 557         free_dns_query(p->query);
 558         free_dns_rr(p->answer);
 559         free_dns_rr(p->authority);
 560         free_dns_rr(p->additional);
 561         free(p);
 562 }
 563
 564 static int
 565 count_dns_rr(struct dns_rr *p, u_int16_t class, u_int16_t type)
 566 {
 567         int n = 0;
 568
 569         while(p) {
 570                 if (p->class == class && p->type == type)
 571                         n++;
 572                 p = p->next;
 573         }
 574
 575         return (n);
 576 }
 577
 578 #endif /* defined(DNS) && !defined(HAVE_GETRRSETBYNAME) */