contrib/bind-9.3/lib/bind/irs/dns_ho.c

   1 /*
   2  * Copyright (c) 1985, 1988, 1993
   3  *    The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. All advertising materials mentioning features or use of this software
  14  *    must display the following acknowledgement:
  15  *      This product includes software developed by the University of
  16  *      California, Berkeley and its contributors.
  17  * 4. Neither the name of the University 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 REGENTS 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 REGENTS 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 /*
  35  * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
  36  * Portions Copyright (c) 1996-1999 by Internet Software Consortium.
  37  *
  38  * Permission to use, copy, modify, and distribute this software for any
  39  * purpose with or without fee is hereby granted, provided that the above
  40  * copyright notice and this permission notice appear in all copies.
  41  *
  42  * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
  43  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  44  * MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR
  45  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  46  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  47  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
  48  * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  49  */
  50
  51 /* from gethostnamadr.c 8.1 (Berkeley) 6/4/93 */
  52 /* BIND Id: gethnamaddr.c,v 8.15 1996/05/22 04:56:30 vixie Exp $ */
  53
  54 #if defined(LIBC_SCCS) && !defined(lint)
  55 static const char rcsid[] = "$Id: dns_ho.c,v 1.5.2.7.4.8 2006/03/10 00:17:21 marka Exp $";
  56 #endif /* LIBC_SCCS and not lint */
  57
  58 /* Imports. */
  59
  60 #include "port_before.h"
  61
  62 #include <sys/types.h>
  63 #include <sys/param.h>
  64 #include <sys/socket.h>
  65
  66 #include <netinet/in.h>
  67 #include <arpa/inet.h>
  68 #include <arpa/nameser.h>
  69
  70 #include <ctype.h>
  71 #include <errno.h>
  72 #include <stdlib.h>
  73 #include <netdb.h>
  74 #include <resolv.h>
  75 #include <stdio.h>
  76 #include <string.h>
  77 #include <syslog.h>
  78
  79 #include <isc/memcluster.h>
  80 #include <irs.h>
  81
  82 #include "port_after.h"
  83
  84 #include "irs_p.h"
  85 #include "dns_p.h"
  86
  87 #ifdef SPRINTF_CHAR
  88 # define SPRINTF(x) strlen(sprintf/**/x)
  89 #else
  90 # define SPRINTF(x) sprintf x
  91 #endif
  92
  93 /* Definitions. */
  94
  95 #define MAXALIASES      35
  96 #define MAXADDRS        35
  97
  98 #define MAXPACKET (65535)       /* Maximum TCP message size */
  99
 100 #define BOUNDS_CHECK(ptr, count) \
 101         if ((ptr) + (count) > eom) { \
 102                 had_error++; \
 103                 continue; \
 104         } else (void)0
 105
 106 typedef union {
 107         HEADER hdr;
 108         u_char buf[MAXPACKET];
 109 } querybuf;
 110
 111 struct dns_res_target {
 112         struct dns_res_target *next;
 113         querybuf qbuf;          /* query buffer */
 114         u_char *answer;         /* buffer to put answer */
 115         int anslen;             /* size of answer buffer */
 116         int qclass, qtype;      /* class and type of query */
 117         int action;             /* condition whether query is really issued */
 118         char qname[MAXDNAME +1]; /* domain name */
 119 #if 0
 120         int n;                  /* result length */
 121 #endif
 122 };
 123 enum {RESTGT_DOALWAYS, RESTGT_AFTERFAILURE, RESTGT_IGNORE};
 124 enum {RESQRY_SUCCESS, RESQRY_FAIL};
 125
 126 struct pvt {
 127         struct hostent  host;
 128         char *          h_addr_ptrs[MAXADDRS + 1];
 129         char *          host_aliases[MAXALIASES];
 130         char            hostbuf[8*1024];
 131         u_char          host_addr[16];  /* IPv4 or IPv6 */
 132         struct __res_state  *res;
 133         void            (*free_res)(void *);
 134 };
 135
 136 typedef union {
 137         int32_t al;
 138         char ac;
 139 } align;
 140
 141 static const u_char mapped[] = { 0,0, 0,0, 0,0, 0,0, 0,0, 0xff,0xff };
 142 static const u_char tunnelled[] = { 0,0, 0,0, 0,0, 0,0, 0,0, 0,0 };
 143 /* Note: the IPv6 loopback address is in the "tunnel" space */
 144 static const u_char v6local[] = { 0,0, 0,1 }; /* last 4 bytes of IPv6 addr */
 145
 146 /* Forwards. */
 147
 148 static void             ho_close(struct irs_ho *this);
 149 static struct hostent * ho_byname(struct irs_ho *this, const char *name);
 150 static struct hostent * ho_byname2(struct irs_ho *this, const char *name,
 151                                    int af);
 152 static struct hostent * ho_byaddr(struct irs_ho *this, const void *addr,
 153                                   int len, int af);
 154 static struct hostent * ho_next(struct irs_ho *this);
 155 static void             ho_rewind(struct irs_ho *this);
 156 static void             ho_minimize(struct irs_ho *this);
 157 static struct __res_state * ho_res_get(struct irs_ho *this);
 158 static void             ho_res_set(struct irs_ho *this,
 159                                    struct __res_state *res,
 160                                    void (*free_res)(void *));
 161 static struct addrinfo * ho_addrinfo(struct irs_ho *this, const char *name,
 162                                      const struct addrinfo *pai);
 163
 164 static void             map_v4v6_hostent(struct hostent *hp, char **bp,
 165                                          char *ep);
 166 static void             addrsort(res_state, char **, int);
 167 static struct hostent * gethostans(struct irs_ho *this,
 168                                    const u_char *ansbuf, int anslen,
 169                                    const char *qname, int qtype,
 170                                    int af, int size,
 171                                    struct addrinfo **ret_aip,
 172                                    const struct addrinfo *pai);
 173 static int add_hostent(struct pvt *pvt, char *bp, char **hap,
 174                        struct addrinfo *ai);
 175 static int              init(struct irs_ho *this);
 176
 177 /* Exports. */
 178
 179 struct irs_ho *
 180 irs_dns_ho(struct irs_acc *this) {
 181         struct irs_ho *ho;
 182         struct pvt *pvt;
 183
 184         UNUSED(this);
 185
 186         if (!(pvt = memget(sizeof *pvt))) {
 187                 errno = ENOMEM;
 188                 return (NULL);
 189         }
 190         memset(pvt, 0, sizeof *pvt);
 191
 192         if (!(ho = memget(sizeof *ho))) {
 193                 memput(pvt, sizeof *pvt);
 194                 errno = ENOMEM;
 195                 return (NULL);
 196         }
 197         memset(ho, 0x5e, sizeof *ho);
 198         ho->private = pvt;
 199         ho->close = ho_close;
 200         ho->byname = ho_byname;
 201         ho->byname2 = ho_byname2;
 202         ho->byaddr = ho_byaddr;
 203         ho->next = ho_next;
 204         ho->rewind = ho_rewind;
 205         ho->minimize = ho_minimize;
 206         ho->res_get = ho_res_get;
 207         ho->res_set = ho_res_set;
 208         ho->addrinfo = ho_addrinfo;
 209         return (ho);
 210 }
 211
 212 /* Methods. */
 213
 214 static void
 215 ho_close(struct irs_ho *this) {
 216         struct pvt *pvt = (struct pvt *)this->private;
 217
 218         ho_minimize(this);
 219         if (pvt->res && pvt->free_res)
 220                 (*pvt->free_res)(pvt->res);
 221         memput(pvt, sizeof *pvt);
 222         memput(this, sizeof *this);
 223 }
 224
 225 static struct hostent *
 226 ho_byname(struct irs_ho *this, const char *name) {
 227         struct pvt *pvt = (struct pvt *)this->private;
 228         struct hostent *hp;
 229
 230         if (init(this) == -1)
 231                 return (NULL);
 232
 233         if (pvt->res->options & RES_USE_INET6) {
 234                 hp = ho_byname2(this, name, AF_INET6);
 235                 if (hp)
 236                         return (hp);
 237         }
 238         return (ho_byname2(this, name, AF_INET));
 239 }
 240
 241 static struct hostent *
 242 ho_byname2(struct irs_ho *this, const char *name, int af)
 243 {
 244         struct pvt *pvt = (struct pvt *)this->private;
 245         struct hostent *hp = NULL;
 246         int n, size;
 247         char tmp[NS_MAXDNAME];
 248         const char *cp;
 249         struct addrinfo ai;
 250         struct dns_res_target *q, *p;
 251         int querystate = RESQRY_FAIL;
 252
 253         if (init(this) == -1)
 254                 return (NULL);
 255
 256         q = memget(sizeof(*q));
 257         if (q == NULL) {
 258                 RES_SET_H_ERRNO(pvt->res, NETDB_INTERNAL);
 259                 errno = ENOMEM;
 260                 goto cleanup;
 261         }
 262         memset(q, 0, sizeof(*q));
 263
 264         switch (af) {
 265         case AF_INET:
 266                 size = INADDRSZ;
 267                 q->qclass = C_IN;
 268                 q->qtype = T_A;
 269                 q->answer = q->qbuf.buf;
 270                 q->anslen = sizeof(q->qbuf);
 271                 q->action = RESTGT_DOALWAYS;
 272                 break;
 273         case AF_INET6:
 274                 size = IN6ADDRSZ;
 275                 q->qclass = C_IN;
 276                 q->qtype = T_AAAA;
 277                 q->answer = q->qbuf.buf;
 278                 q->anslen = sizeof(q->qbuf);
 279                 q->action = RESTGT_DOALWAYS;
 280                 break;
 281         default:
 282                 RES_SET_H_ERRNO(pvt->res, NETDB_INTERNAL);
 283                 errno = EAFNOSUPPORT;
 284                 hp = NULL;
 285                 goto cleanup;
 286         }
 287
 288         /*
 289          * if there aren't any dots, it could be a user-level alias.
 290          * this is also done in res_nquery() since we are not the only
 291          * function that looks up host names.
 292          */
 293         if (!strchr(name, '.') && (cp = res_hostalias(pvt->res, name,
 294                                                       tmp, sizeof tmp)))
 295                 name = cp;
 296
 297         for (p = q; p; p = p->next) {
 298                 switch(p->action) {
 299                 case RESTGT_DOALWAYS:
 300                         break;
 301                 case RESTGT_AFTERFAILURE:
 302                         if (querystate == RESQRY_SUCCESS)
 303                                 continue;
 304                         break;
 305                 case RESTGT_IGNORE:
 306                         continue;
 307                 }
 308
 309                 if ((n = res_nsearch(pvt->res, name, p->qclass, p->qtype,
 310                                      p->answer, p->anslen)) < 0) {
 311                         querystate = RESQRY_FAIL;
 312                         continue;
 313                 }
 314
 315                 memset(&ai, 0, sizeof(ai));
 316                 ai.ai_family = af;
 317                 if ((hp = gethostans(this, p->answer, n, name, p->qtype,
 318                                      af, size, NULL,
 319                                      (const struct addrinfo *)&ai)) != NULL)
 320                         goto cleanup;   /* no more loop is necessary */
 321
 322                 querystate = RESQRY_FAIL;
 323                 continue;
 324         }
 325
 326  cleanup:
 327         if (q != NULL)
 328                 memput(q, sizeof(*q));
 329         return(hp);
 330 }
 331
 332 static struct hostent *
 333 ho_byaddr(struct irs_ho *this, const void *addr, int len, int af)
 334 {
 335         struct pvt *pvt = (struct pvt *)this->private;
 336         const u_char *uaddr = addr;
 337         char *qp;
 338         struct hostent *hp = NULL;
 339         struct addrinfo ai;
 340         struct dns_res_target *q, *q2, *p;
 341         int n, size, i;
 342         int querystate = RESQRY_FAIL;
 343
 344         if (init(this) == -1)
 345                 return (NULL);
 346
 347         q = memget(sizeof(*q));
 348         q2 = memget(sizeof(*q2));
 349         if (q == NULL || q2 == NULL) {
 350                 RES_SET_H_ERRNO(pvt->res, NETDB_INTERNAL);
 351                 errno = ENOMEM;
 352                 goto cleanup;
 353         }
 354         memset(q, 0, sizeof(*q));
 355         memset(q2, 0, sizeof(*q2));
 356
 357         if (af == AF_INET6 && len == IN6ADDRSZ &&
 358             (!memcmp(uaddr, mapped, sizeof mapped) ||
 359            (!memcmp(uaddr, tunnelled, sizeof tunnelled) &&
 360             memcmp(&uaddr[sizeof tunnelled], v6local, sizeof(v6local))))) {
 361                 /* Unmap. */
 362                 addr = (const char *)addr + sizeof mapped;
 363                 uaddr += sizeof mapped;
 364                 af = AF_INET;
 365                 len = INADDRSZ;
 366         }
 367         switch (af) {
 368         case AF_INET:
 369                 size = INADDRSZ;
 370                 q->qclass = C_IN;
 371                 q->qtype = T_PTR;
 372                 q->answer = q->qbuf.buf;
 373                 q->anslen = sizeof(q->qbuf);
 374                 q->action = RESTGT_DOALWAYS;
 375                 break;
 376         case AF_INET6:
 377                 size = IN6ADDRSZ;
 378                 q->qclass = C_IN;
 379                 q->qtype = T_PTR;
 380                 q->answer = q->qbuf.buf;
 381                 q->anslen = sizeof(q->qbuf);
 382                 q->next = q2;
 383                 q->action = RESTGT_DOALWAYS;
 384                 q2->qclass = C_IN;
 385                 q2->qtype = T_PTR;
 386                 q2->answer = q2->qbuf.buf;
 387                 q2->anslen = sizeof(q2->qbuf);
 388                 if ((pvt->res->options & RES_NO_NIBBLE2) != 0U)
 389                         q2->action = RESTGT_IGNORE;
 390                 else
 391                         q2->action = RESTGT_AFTERFAILURE;
 392                 break;
 393         default:
 394                 errno = EAFNOSUPPORT;
 395                 RES_SET_H_ERRNO(pvt->res, NETDB_INTERNAL);
 396                 hp = NULL;
 397                 goto cleanup;
 398         }
 399         if (size > len) {
 400                 errno = EINVAL;
 401                 RES_SET_H_ERRNO(pvt->res, NETDB_INTERNAL);
 402                 hp = NULL;
 403                 goto cleanup;
 404         }
 405         switch (af) {
 406         case AF_INET:
 407                 qp = q->qname;
 408                 (void) sprintf(qp, "%u.%u.%u.%u.in-addr.arpa",
 409                                (uaddr[3] & 0xff),
 410                                (uaddr[2] & 0xff),
 411                                (uaddr[1] & 0xff),
 412                                (uaddr[0] & 0xff));
 413                 break;
 414         case AF_INET6:
 415                 if (q->action != RESTGT_IGNORE) {
 416                         const char *nibsuff = res_get_nibblesuffix(pvt->res);
 417                         qp = q->qname;
 418                         for (n = IN6ADDRSZ - 1; n >= 0; n--) {
 419                                 i = SPRINTF((qp, "%x.%x.",
 420                                                uaddr[n] & 0xf,
 421                                                (uaddr[n] >> 4) & 0xf));
 422                                 if (i != 4)
 423                                         abort();
 424                                 qp += i;
 425                         }
 426                         if (strlen(q->qname) + strlen(nibsuff) + 1 >
 427                             sizeof q->qname) {
 428                                 errno = ENAMETOOLONG;
 429                                 RES_SET_H_ERRNO(pvt->res, NETDB_INTERNAL);
 430                                 hp = NULL;
 431                                 goto cleanup;
 432                         }
 433                         strcpy(qp, nibsuff);    /* (checked) */
 434                 }
 435                 if (q2->action != RESTGT_IGNORE) {
 436                         const char *nibsuff2 = res_get_nibblesuffix2(pvt->res);
 437                         qp = q2->qname;
 438                         for (n = IN6ADDRSZ - 1; n >= 0; n--) {
 439                                 i = SPRINTF((qp, "%x.%x.",
 440                                                uaddr[n] & 0xf,
 441                                                (uaddr[n] >> 4) & 0xf));
 442                                 if (i != 4)
 443                                         abort();
 444                                 qp += i;
 445                         }
 446                         if (strlen(q2->qname) + strlen(nibsuff2) + 1 >
 447                             sizeof q2->qname) {
 448                                 errno = ENAMETOOLONG;
 449                                 RES_SET_H_ERRNO(pvt->res, NETDB_INTERNAL);
 450                                 hp = NULL;
 451                                 goto cleanup;
 452                         }
 453                         strcpy(qp, nibsuff2);   /* (checked) */
 454                 }
 455                 break;
 456         default:
 457                 abort();
 458         }
 459
 460         for (p = q; p; p = p->next) {
 461                 switch(p->action) {
 462                 case RESTGT_DOALWAYS:
 463                         break;
 464                 case RESTGT_AFTERFAILURE:
 465                         if (querystate == RESQRY_SUCCESS)
 466                                 continue;
 467                         break;
 468                 case RESTGT_IGNORE:
 469                         continue;
 470                 }
 471
 472                 if ((n = res_nquery(pvt->res, p->qname, p->qclass, p->qtype,
 473                                     p->answer, p->anslen)) < 0) {
 474                         querystate = RESQRY_FAIL;
 475                         continue;
 476                 }
 477
 478                 memset(&ai, 0, sizeof(ai));
 479                 ai.ai_family = af;
 480                 hp = gethostans(this, p->answer, n, p->qname, T_PTR, af, size,
 481                                 NULL, (const struct addrinfo *)&ai);
 482                 if (!hp) {
 483                         querystate = RESQRY_FAIL;
 484                         continue;
 485                 }
 486
 487                 memcpy(pvt->host_addr, addr, len);
 488                 pvt->h_addr_ptrs[0] = (char *)pvt->host_addr;
 489                 pvt->h_addr_ptrs[1] = NULL;
 490                 if (af == AF_INET && (pvt->res->options & RES_USE_INET6)) {
 491                         map_v4v6_address((char*)pvt->host_addr,
 492                                          (char*)pvt->host_addr);
 493                         pvt->host.h_addrtype = AF_INET6;
 494                         pvt->host.h_length = IN6ADDRSZ;
 495                 }
 496
 497                 RES_SET_H_ERRNO(pvt->res, NETDB_SUCCESS);
 498                 goto cleanup;   /* no more loop is necessary. */
 499         }
 500         hp = NULL; /* H_ERRNO was set by subroutines */
 501
 502  cleanup:
 503         if (q != NULL)
 504                 memput(q, sizeof(*q));
 505         if (q2 != NULL)
 506                 memput(q2, sizeof(*q2));
 507         return(hp);
 508 }
 509
 510 static struct hostent *
 511 ho_next(struct irs_ho *this) {
 512
 513         UNUSED(this);
 514
 515         return (NULL);
 516 }
 517
 518 static void
 519 ho_rewind(struct irs_ho *this) {
 520
 521         UNUSED(this);
 522
 523         /* NOOP */
 524 }
 525
 526 static void
 527 ho_minimize(struct irs_ho *this) {
 528         struct pvt *pvt = (struct pvt *)this->private;
 529
 530         if (pvt->res)
 531                 res_nclose(pvt->res);
 532 }
 533
 534 static struct __res_state *
 535 ho_res_get(struct irs_ho *this) {
 536         struct pvt *pvt = (struct pvt *)this->private;
 537
 538         if (!pvt->res) {
 539                 struct __res_state *res;
 540                 res = (struct __res_state *)malloc(sizeof *res);
 541                 if (!res) {
 542                         errno = ENOMEM;
 543                         return (NULL);
 544                 }
 545                 memset(res, 0, sizeof *res);
 546                 ho_res_set(this, res, free);
 547         }
 548
 549         return (pvt->res);
 550 }
 551
 552 /* XXX */
 553 extern struct addrinfo *addr2addrinfo __P((const struct addrinfo *,
 554                                            const char *));
 555
 556 static struct addrinfo *
 557 ho_addrinfo(struct irs_ho *this, const char *name, const struct addrinfo *pai)
 558 {
 559         struct pvt *pvt = (struct pvt *)this->private;
 560         int n;
 561         char tmp[NS_MAXDNAME];
 562         const char *cp;
 563         struct dns_res_target *q, *q2, *p;
 564         struct addrinfo sentinel, *cur;
 565         int querystate = RESQRY_FAIL;
 566
 567         if (init(this) == -1)
 568                 return (NULL);
 569
 570         memset(&sentinel, 0, sizeof(sentinel));
 571         cur = &sentinel;
 572
 573         q = memget(sizeof(*q));
 574         q2 = memget(sizeof(*q2));
 575         if (q == NULL || q2 == NULL) {
 576                 RES_SET_H_ERRNO(pvt->res, NETDB_INTERNAL);
 577                 errno = ENOMEM;
 578                 goto cleanup;
 579         }
 580         memset(q, 0, sizeof(*q2));
 581         memset(q2, 0, sizeof(*q2));
 582
 583         switch (pai->ai_family) {
 584         case AF_UNSPEC:
 585                 /* prefer IPv6 */
 586                 q->qclass = C_IN;
 587                 q->qtype = T_AAAA;
 588                 q->answer = q->qbuf.buf;
 589                 q->anslen = sizeof(q->qbuf);
 590                 q->next = q2;
 591                 q->action = RESTGT_DOALWAYS;
 592                 q2->qclass = C_IN;
 593                 q2->qtype = T_A;
 594                 q2->answer = q2->qbuf.buf;
 595                 q2->anslen = sizeof(q2->qbuf);
 596                 q2->action = RESTGT_DOALWAYS;
 597                 break;
 598         case AF_INET:
 599                 q->qclass = C_IN;
 600                 q->qtype = T_A;
 601                 q->answer = q->qbuf.buf;
 602                 q->anslen = sizeof(q->qbuf);
 603                 q->action = RESTGT_DOALWAYS;
 604                 break;
 605         case AF_INET6:
 606                 q->qclass = C_IN;
 607                 q->qtype = T_AAAA;
 608                 q->answer = q->qbuf.buf;
 609                 q->anslen = sizeof(q->qbuf);
 610                 q->action = RESTGT_DOALWAYS;
 611                 break;
 612         default:
 613                 RES_SET_H_ERRNO(pvt->res, NO_RECOVERY); /* better error? */
 614                 goto cleanup;
 615         }
 616
 617         /*
 618          * if there aren't any dots, it could be a user-level alias.
 619          * this is also done in res_nquery() since we are not the only
 620          * function that looks up host names.
 621          */
 622         if (!strchr(name, '.') && (cp = res_hostalias(pvt->res, name,
 623                                                       tmp, sizeof tmp)))
 624                 name = cp;
 625
 626         for (p = q; p; p = p->next) {
 627                 struct addrinfo *ai;
 628
 629                 switch(p->action) {
 630                 case RESTGT_DOALWAYS:
 631                         break;
 632                 case RESTGT_AFTERFAILURE:
 633                         if (querystate == RESQRY_SUCCESS)
 634                                 continue;
 635                         break;
 636                 case RESTGT_IGNORE:
 637                         continue;
 638                 }
 639
 640                 if ((n = res_nsearch(pvt->res, name, p->qclass, p->qtype,
 641                                      p->answer, p->anslen)) < 0) {
 642                         querystate = RESQRY_FAIL;
 643                         continue;
 644                 }
 645                 (void)gethostans(this, p->answer, n, name, p->qtype,
 646                                  pai->ai_family, /* XXX: meaningless */
 647                                  0, &ai, pai);
 648                 if (ai) {
 649                         querystate = RESQRY_SUCCESS;
 650                         cur->ai_next = ai;
 651                         while (cur->ai_next)
 652                                 cur = cur->ai_next;
 653                 } else
 654                         querystate = RESQRY_FAIL;
 655         }
 656
 657  cleanup:
 658         if (q != NULL)
 659                 memput(q, sizeof(*q));
 660         if (q2 != NULL)
 661                 memput(q2, sizeof(*q2));
 662         return(sentinel.ai_next);
 663 }
 664
 665 static void
 666 ho_res_set(struct irs_ho *this, struct __res_state *res,
 667                 void (*free_res)(void *)) {
 668         struct pvt *pvt = (struct pvt *)this->private;
 669
 670         if (pvt->res && pvt->free_res) {
 671                 res_nclose(pvt->res);
 672                 (*pvt->free_res)(pvt->res);
 673         }
 674
 675         pvt->res = res;
 676         pvt->free_res = free_res;
 677 }
 678
 679 /* Private. */
 680
 681 static struct hostent *
 682 gethostans(struct irs_ho *this,
 683            const u_char *ansbuf, int anslen, const char *qname, int qtype,
 684            int af, int size,    /* meaningless for addrinfo cases */
 685            struct addrinfo **ret_aip, const struct addrinfo *pai)
 686 {
 687         struct pvt *pvt = (struct pvt *)this->private;
 688         int type, class, ancount, qdcount, n, haveanswer, had_error;
 689         int error = NETDB_SUCCESS;
 690         int (*name_ok)(const char *);
 691         const HEADER *hp;
 692         const u_char *eom;
 693         const u_char *eor;
 694         const u_char *cp;
 695         const char *tname;
 696         const char *hname;
 697         char *bp, *ep, **ap, **hap;
 698         char tbuf[MAXDNAME+1];
 699         struct addrinfo sentinel, *cur, ai;
 700
 701         if (pai == NULL) abort();
 702         if (ret_aip != NULL)
 703                 *ret_aip = NULL;
 704         memset(&sentinel, 0, sizeof(sentinel));
 705         cur = &sentinel;
 706
 707         tname = qname;
 708         eom = ansbuf + anslen;
 709         switch (qtype) {
 710         case T_A:
 711         case T_AAAA:
 712         case T_ANY:     /* use T_ANY only for T_A/T_AAAA lookup */
 713                 name_ok = res_hnok;
 714                 break;
 715         case T_PTR:
 716                 name_ok = res_dnok;
 717                 break;
 718         default:
 719                 abort();
 720         }
 721
 722         pvt->host.h_addrtype = af;
 723         pvt->host.h_length = size;
 724         hname = pvt->host.h_name = NULL;
 725
 726         /*
 727          * Find first satisfactory answer.
 728          */
 729         if (ansbuf + HFIXEDSZ > eom) {
 730                 RES_SET_H_ERRNO(pvt->res, NO_RECOVERY);
 731                 return (NULL);
 732         }
 733         hp = (const HEADER *)ansbuf;
 734         ancount = ntohs(hp->ancount);
 735         qdcount = ntohs(hp->qdcount);
 736         bp = pvt->hostbuf;
 737         ep = pvt->hostbuf + sizeof(pvt->hostbuf);
 738         cp = ansbuf + HFIXEDSZ;
 739         if (qdcount != 1) {
 740                 RES_SET_H_ERRNO(pvt->res, NO_RECOVERY);
 741                 return (NULL);
 742         }
 743         n = dn_expand(ansbuf, eom, cp, bp, ep - bp);
 744         if (n < 0 || !maybe_ok(pvt->res, bp, name_ok)) {
 745                 RES_SET_H_ERRNO(pvt->res, NO_RECOVERY);
 746                 return (NULL);
 747         }
 748         cp += n + QFIXEDSZ;
 749         if (cp > eom) {
 750                 RES_SET_H_ERRNO(pvt->res, NO_RECOVERY);
 751                 return (NULL);
 752         }
 753         if (qtype == T_A || qtype == T_AAAA || qtype == T_ANY) {
 754                 /* res_nsend() has already verified that the query name is the
 755                  * same as the one we sent; this just gets the expanded name
 756                  * (i.e., with the succeeding search-domain tacked on).
 757                  */
 758                 n = strlen(bp) + 1;             /* for the \0 */
 759                 if (n > MAXHOSTNAMELEN) {
 760                         RES_SET_H_ERRNO(pvt->res, NO_RECOVERY);
 761                         return (NULL);
 762                 }
 763                 pvt->host.h_name = bp;
 764                 hname = bp;
 765                 bp += n;
 766                 /* The qname can be abbreviated, but hname is now absolute. */
 767                 qname = pvt->host.h_name;
 768         }
 769         ap = pvt->host_aliases;
 770         *ap = NULL;
 771         pvt->host.h_aliases = pvt->host_aliases;
 772         hap = pvt->h_addr_ptrs;
 773         *hap = NULL;
 774         pvt->host.h_addr_list = pvt->h_addr_ptrs;
 775         haveanswer = 0;
 776         had_error = 0;
 777         while (ancount-- > 0 && cp < eom && !had_error) {
 778                 n = dn_expand(ansbuf, eom, cp, bp, ep - bp);
 779                 if (n < 0 || !maybe_ok(pvt->res, bp, name_ok)) {
 780                         had_error++;
 781                         continue;
 782                 }
 783                 cp += n;                        /* name */
 784                 BOUNDS_CHECK(cp, 3 * INT16SZ + INT32SZ);
 785                 type = ns_get16(cp);
 786                 cp += INT16SZ;                  /* type */
 787                 class = ns_get16(cp);
 788                 cp += INT16SZ + INT32SZ;        /* class, TTL */
 789                 n = ns_get16(cp);
 790                 cp += INT16SZ;                  /* len */
 791                 BOUNDS_CHECK(cp, n);
 792                 if (class != C_IN) {
 793                         cp += n;
 794                         continue;
 795                 }
 796                 eor = cp + n;
 797                 if ((qtype == T_A || qtype == T_AAAA || qtype == T_ANY) &&
 798                     type == T_CNAME) {
 799                         if (haveanswer) {
 800                                 int level = LOG_CRIT;
 801 #ifdef LOG_SECURITY
 802                                 level |= LOG_SECURITY;
 803 #endif
 804                                 syslog(level,
 805  "gethostans: possible attempt to exploit buffer overflow while looking up %s",
 806                                         *qname ? qname : ".");
 807                         }
 808                         n = dn_expand(ansbuf, eor, cp, tbuf, sizeof tbuf);
 809                         if (n < 0 || !maybe_ok(pvt->res, tbuf, name_ok)) {
 810                                 had_error++;
 811                                 continue;
 812                         }
 813                         cp += n;
 814                         /* Store alias. */
 815                         if (ap >= &pvt->host_aliases[MAXALIASES-1])
 816                                 continue;
 817                         *ap++ = bp;
 818                         n = strlen(bp) + 1;     /* for the \0 */
 819                         bp += n;
 820                         /* Get canonical name. */
 821                         n = strlen(tbuf) + 1;   /* for the \0 */
 822                         if (n > (ep - bp) || n > MAXHOSTNAMELEN) {
 823                                 had_error++;
 824                                 continue;
 825                         }
 826                         strcpy(bp, tbuf);       /* (checked) */
 827                         pvt->host.h_name = bp;
 828                         hname = bp;
 829                         bp += n;
 830                         continue;
 831                 }
 832                 if (qtype == T_PTR && type == T_CNAME) {
 833                         n = dn_expand(ansbuf, eor, cp, tbuf, sizeof tbuf);
 834                         if (n < 0 || !maybe_dnok(pvt->res, tbuf)) {
 835                                 had_error++;
 836                                 continue;
 837                         }
 838                         cp += n;
 839 #ifdef RES_USE_DNAME
 840                         if ((pvt->res->options & RES_USE_DNAME) != 0U)
 841 #endif
 842                         {
 843                                 /*
 844                                  * We may be able to check this regardless
 845                                  * of the USE_DNAME bit, but we add the check
 846                                  * for now since the DNAME support is
 847                                  * experimental.
 848                                  */
 849                                 if (ns_samename(tname, bp) != 1)
 850                                         continue;
 851                         }
 852                         /* Get canonical name. */
 853                         n = strlen(tbuf) + 1;   /* for the \0 */
 854                         if (n > (ep - bp)) {
 855                                 had_error++;
 856                                 continue;
 857                         }
 858                         strcpy(bp, tbuf);       /* (checked) */
 859                         tname = bp;
 860                         bp += n;
 861                         continue;
 862                 }
 863                 if (qtype == T_ANY) {
 864                         if (!(type == T_A || type == T_AAAA)) {
 865                                 cp += n;
 866                                 continue;
 867                         }
 868                 } else if (type != qtype) {
 869                         cp += n;
 870                         continue;
 871                 }
 872                 switch (type) {
 873                 case T_PTR:
 874                         if (ret_aip != NULL) {
 875                                 /* addrinfo never needs T_PTR */
 876                                 cp += n;
 877                                 continue;
 878                         }
 879                         if (ns_samename(tname, bp) != 1) {
 880                                 cp += n;
 881                                 continue;
 882                         }
 883                         n = dn_expand(ansbuf, eor, cp, bp, ep - bp);
 884                         if (n < 0 || !maybe_hnok(pvt->res, bp) ||
 885                             n >= MAXHOSTNAMELEN) {
 886                                 had_error++;
 887                                 break;
 888                         }
 889                         cp += n;
 890                         if (!haveanswer) {
 891                                 pvt->host.h_name = bp;
 892                                 hname = bp;
 893                         }
 894                         else if (ap < &pvt->host_aliases[MAXALIASES-1])
 895                                 *ap++ = bp;
 896                         else
 897                                 n = -1;
 898                         if (n != -1) {
 899                                 n = strlen(bp) + 1;     /* for the \0 */
 900                                 bp += n;
 901                         }
 902                         break;
 903                 case T_A:
 904                 case T_AAAA:
 905                         if (ns_samename(hname, bp) != 1) {
 906                                 cp += n;
 907                                 continue;
 908                         }
 909                         if (type == T_A && n != INADDRSZ) {
 910                                 cp += n;
 911                                 continue;
 912                         }
 913                         if (type == T_AAAA && n != IN6ADDRSZ) {
 914                                 cp += n;
 915                                 continue;
 916                         }
 917
 918                         /* make addrinfo. don't overwrite constant PAI */
 919                         ai = *pai;
 920                         ai.ai_family = (type == T_AAAA) ? AF_INET6 : AF_INET;
 921                         cur->ai_next = addr2addrinfo(
 922                                         (const struct addrinfo *)&ai,
 923                                         (const char *)cp);
 924                         if (cur->ai_next == NULL)
 925                                 had_error++;
 926
 927                         if (!haveanswer) {
 928                                 int nn;
 929
 930                                 nn = strlen(bp) + 1;    /* for the \0 */
 931                                 if (nn >= MAXHOSTNAMELEN) {
 932                                         cp += n;
 933                                         had_error++;
 934                                         continue;
 935                                 }
 936                                 pvt->host.h_name = bp;
 937                                 hname = bp;
 938                                 bp += nn;
 939                         }
 940                         /* Ensure alignment. */
 941                         bp = (char *)(((u_long)bp + (sizeof(align) - 1)) &
 942                                       ~(sizeof(align) - 1));
 943                         /* Avoid overflows. */
 944                         if (bp + n >= &pvt->hostbuf[sizeof pvt->hostbuf]) {
 945                                 had_error++;
 946                                 continue;
 947                         }
 948                         if (ret_aip) { /* need addrinfo. keep it. */
 949                                 while (cur->ai_next)
 950                                         cur = cur->ai_next;
 951                         } else if (cur->ai_next) { /* need hostent */
 952                                 struct addrinfo *aip = cur->ai_next;
 953
 954                                 for (aip = cur->ai_next; aip;
 955                                      aip = aip->ai_next) {
 956                                         int m;
 957
 958                                         m = add_hostent(pvt, bp, hap, aip);
 959                                         if (m < 0) {
 960                                                 had_error++;
 961                                                 break;
 962                                         }
 963                                         if (m == 0)
 964                                                 continue;
 965                                         if (hap < &pvt->h_addr_ptrs[MAXADDRS-1])
 966                                                 hap++;
 967                                         *hap = NULL;
 968                                         bp += m;
 969                                 }
 970
 971                                 freeaddrinfo(cur->ai_next);
 972                                 cur->ai_next = NULL;
 973                         }
 974                         cp += n;
 975                         break;
 976                 default:
 977                         abort();
 978                 }
 979                 if (!had_error)
 980                         haveanswer++;
 981         }
 982         if (haveanswer) {
 983                 if (ret_aip == NULL) {
 984                         *ap = NULL;
 985                         *hap = NULL;
 986
 987                         if (pvt->res->nsort && haveanswer > 1 && qtype == T_A)
 988                                 addrsort(pvt->res, pvt->h_addr_ptrs,
 989                                          haveanswer);
 990                         if (pvt->host.h_name == NULL) {
 991                                 n = strlen(qname) + 1;  /* for the \0 */
 992                                 if (n > (ep - bp) || n >= MAXHOSTNAMELEN)
 993                                         goto no_recovery;
 994                                 strcpy(bp, qname);      /* (checked) */
 995                                 pvt->host.h_name = bp;
 996                                 bp += n;
 997                         }
 998                         if (pvt->res->options & RES_USE_INET6)
 999                                 map_v4v6_hostent(&pvt->host, &bp, ep);
1000                         RES_SET_H_ERRNO(pvt->res, NETDB_SUCCESS);
1001                         return (&pvt->host);
1002                 } else {
1003                         if ((pai->ai_flags & AI_CANONNAME) != 0) {
1004                                 if (pvt->host.h_name == NULL) {
1005                                         sentinel.ai_next->ai_canonname =
1006                                                 strdup(qname);
1007                                 }
1008                                 else {
1009                                         sentinel.ai_next->ai_canonname =
1010                                                 strdup(pvt->host.h_name);
1011                                 }
1012                         }
1013                         *ret_aip = sentinel.ai_next;
1014                         return(NULL);
1015                 }
1016         }
1017  no_recovery:
1018         if (sentinel.ai_next) {
1019                 /* this should be impossible, but check it for safety */
1020                 freeaddrinfo(sentinel.ai_next);
1021         }
1022         if (error == NETDB_SUCCESS)
1023                 RES_SET_H_ERRNO(pvt->res, NO_RECOVERY);
1024         else
1025                 RES_SET_H_ERRNO(pvt->res, error);
1026         return(NULL);
1027 }
1028
1029 static int
1030 add_hostent(struct pvt *pvt, char *bp, char **hap, struct addrinfo *ai)
1031 {
1032         int addrlen;
1033         char *addrp;
1034         const char **tap;
1035         char *obp = bp;
1036
1037         switch(ai->ai_addr->sa_family) {
1038         case AF_INET6:
1039                 addrlen = IN6ADDRSZ;
1040                 addrp = (char *)&((struct sockaddr_in6 *)ai->ai_addr)->sin6_addr;
1041                 break;
1042         case AF_INET:
1043                 addrlen = INADDRSZ;
1044                 addrp = (char *)&((struct sockaddr_in *)ai->ai_addr)->sin_addr;
1045                 break;
1046         default:
1047                 return(-1);     /* abort? */
1048         }
1049
1050         /* Ensure alignment. */
1051         bp = (char *)(((u_long)bp + (sizeof(align) - 1)) &
1052                       ~(sizeof(align) - 1));
1053         /* Avoid overflows. */
1054         if (bp + addrlen >= &pvt->hostbuf[sizeof pvt->hostbuf])
1055                 return(-1);
1056         if (hap >= &pvt->h_addr_ptrs[MAXADDRS-1])
1057                 return(0); /* fail, but not treat it as an error. */
1058
1059         /* Suppress duplicates. */
1060         for (tap = (const char **)pvt->h_addr_ptrs;
1061              *tap != NULL;
1062              tap++)
1063                 if (memcmp(*tap, addrp, addrlen) == 0)
1064                         break;
1065         if (*tap != NULL)
1066                 return (0);
1067
1068         memcpy(*hap = bp, addrp, addrlen);
1069         return((bp + addrlen) - obp);
1070 }
1071
1072 static void
1073 map_v4v6_hostent(struct hostent *hp, char **bpp, char *ep) {
1074         char **ap;
1075
1076         if (hp->h_addrtype != AF_INET || hp->h_length != INADDRSZ)
1077                 return;
1078         hp->h_addrtype = AF_INET6;
1079         hp->h_length = IN6ADDRSZ;
1080         for (ap = hp->h_addr_list; *ap; ap++) {
1081                 int i = (u_long)*bpp % sizeof(align);
1082
1083                 if (i != 0)
1084                         i = sizeof(align) - i;
1085
1086                 if ((ep - *bpp) < (i + IN6ADDRSZ)) {
1087                         /* Out of memory.  Truncate address list here. */
1088                         *ap = NULL;
1089                         return;
1090                 }
1091                 *bpp += i;
1092                 map_v4v6_address(*ap, *bpp);
1093                 *ap = *bpp;
1094                 *bpp += IN6ADDRSZ;
1095         }
1096 }
1097
1098 static void
1099 addrsort(res_state statp, char **ap, int num) {
1100         int i, j, needsort = 0, aval[MAXADDRS];
1101         char **p;
1102
1103         p = ap;
1104         for (i = 0; i < num; i++, p++) {
1105                 for (j = 0 ; (unsigned)j < statp->nsort; j++)
1106                         if (statp->sort_list[j].addr.s_addr ==
1107                             (((struct in_addr *)(*p))->s_addr &
1108                              statp->sort_list[j].mask))
1109                                 break;
1110                 aval[i] = j;
1111                 if (needsort == 0 && i > 0 && j < aval[i-1])
1112                         needsort = i;
1113         }
1114         if (!needsort)
1115                 return;
1116
1117         while (needsort < num) {
1118                 for (j = needsort - 1; j >= 0; j--) {
1119                         if (aval[j] > aval[j+1]) {
1120                                 char *hp;
1121
1122                                 i = aval[j];
1123                                 aval[j] = aval[j+1];
1124                                 aval[j+1] = i;
1125
1126                                 hp = ap[j];
1127                                 ap[j] = ap[j+1];
1128                                 ap[j+1] = hp;
1129
1130                         } else
1131                                 break;
1132                 }
1133                 needsort++;
1134         }
1135 }
1136
1137 static int
1138 init(struct irs_ho *this) {
1139         struct pvt *pvt = (struct pvt *)this->private;
1140
1141         if (!pvt->res && !ho_res_get(this))
1142                 return (-1);
1143         if (((pvt->res->options & RES_INIT) == 0U) &&
1144             res_ninit(pvt->res) == -1)
1145                 return (-1);
1146         return (0);
1147 }