nis/nss_nis/nis-hosts.c

   1 /* Copyright (C) 1996-2017 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Thorsten Kukuk <kukuk@suse.de>, 1996.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 #include <assert.h>
  20 #include <nss.h>
  21 #include <ctype.h>
  22 /* The following is an ugly trick to avoid a prototype declaration for
  23    _nss_nis_endgrent.  */
  24 #define _nss_nis_endhostent _nss_nis_endhostent_XXX
  25 #include <netdb.h>
  26 #undef _nss_nis_endhostent
  27 #include <string.h>
  28 #include <netinet/in.h>
  29 #include <arpa/inet.h>
  30 #include <resolv/resolv-internal.h>
  31 #include <libc-lock.h>
  32 #include <rpcsvc/yp.h>
  33 #include <rpcsvc/ypclnt.h>
  34
  35 #include "nss-nis.h"
  36
  37 /* Get implementation for some internal functions. */
  38 #include <resolv/mapv4v6addr.h>
  39
  40 #define ENTNAME         hostent
  41 #define DATABASE        "hosts"
  42 #define NEED_H_ERRNO
  43
  44 #define EXTRA_ARGS      , af, flags
  45 #define EXTRA_ARGS_DECL , int af, int flags
  46
  47 #define ENTDATA hostent_data
  48 struct hostent_data
  49   {
  50     unsigned char host_addr[16];        /* IPv4 or IPv6 address.  */
  51     char *h_addr_ptrs[2];       /* Points to that and null terminator.  */
  52   };
  53
  54 #define TRAILING_LIST_MEMBER            h_aliases
  55 #define TRAILING_LIST_SEPARATOR_P       isspace
  56 #include <nss/nss_files/files-parse.c>
  57 LINE_PARSER
  58 ("#",
  59  {
  60    char *addr;
  61
  62    STRING_FIELD (addr, isspace, 1);
  63
  64    assert (af == AF_INET || af == AF_INET6 || af == AF_UNSPEC);
  65
  66    /* Parse address.  */
  67    if (af != AF_INET6 && inet_pton (AF_INET, addr, entdata->host_addr) > 0)
  68      {
  69        assert ((flags & AI_V4MAPPED) == 0 || af != AF_UNSPEC);
  70        if (flags & AI_V4MAPPED)
  71          {
  72            map_v4v6_address ((char *) entdata->host_addr,
  73                              (char *) entdata->host_addr);
  74            result->h_addrtype = AF_INET6;
  75            result->h_length = IN6ADDRSZ;
  76          }
  77        else
  78          {
  79            result->h_addrtype = AF_INET;
  80            result->h_length = INADDRSZ;
  81          }
  82      }
  83    else if (af != AF_INET
  84             && inet_pton (AF_INET6, addr, entdata->host_addr) > 0)
  85      {
  86        result->h_addrtype = AF_INET6;
  87        result->h_length = IN6ADDRSZ;
  88      }
  89    else
  90      /* Illegal address: ignore line.  */
  91      return 0;
  92
  93    /* Store a pointer to the address in the expected form.  */
  94    entdata->h_addr_ptrs[0] = (char *) entdata->host_addr;
  95    entdata->h_addr_ptrs[1] = NULL;
  96    result->h_addr_list = entdata->h_addr_ptrs;
  97
  98    STRING_FIELD (result->h_name, isspace, 1);
  99  })
 100
 101
 102 __libc_lock_define_initialized (static, lock)
 103
 104 static bool_t new_start = 1;
 105 static char *oldkey = NULL;
 106 static int oldkeylen = 0;
 107
 108
 109 enum nss_status
 110 _nss_nis_sethostent (int stayopen)
 111 {
 112   __libc_lock_lock (lock);
 113
 114   new_start = 1;
 115   if (oldkey != NULL)
 116     {
 117       free (oldkey);
 118       oldkey = NULL;
 119       oldkeylen = 0;
 120     }
 121
 122   __libc_lock_unlock (lock);
 123
 124   return NSS_STATUS_SUCCESS;
 125 }
 126 /* Make _nss_nis_endhostent an alias of _nss_nis_sethostent.  We do this
 127    even though the prototypes don't match.  The argument of sethostent
 128    is used so this makes no difference.  */
 129 strong_alias (_nss_nis_sethostent, _nss_nis_endhostent)
 130
 131
 132 /* The calling function always need to get a lock first. */
 133 static enum nss_status
 134 internal_nis_gethostent_r (struct hostent *host, char *buffer,
 135                            size_t buflen, int *errnop, int *h_errnop,
 136                            int af, int flags)
 137 {
 138   char *domain;
 139   if (__glibc_unlikely (yp_get_default_domain (&domain)))
 140     return NSS_STATUS_UNAVAIL;
 141
 142   uintptr_t pad = -(uintptr_t) buffer % __alignof__ (struct parser_data);
 143   buffer += pad;
 144
 145   struct parser_data *data = (void *) buffer;
 146   if (__glibc_unlikely (buflen < sizeof *data + 1 + pad))
 147     {
 148       *errnop = ERANGE;
 149       *h_errnop = NETDB_INTERNAL;
 150       return NSS_STATUS_TRYAGAIN;
 151     }
 152   buflen -= pad;
 153
 154   /* Get the next entry until we found a correct one. */
 155   const size_t linebuflen = buffer + buflen - data->linebuffer;
 156   int parse_res;
 157   do
 158     {
 159       char *result;
 160       int len;
 161       char *outkey;
 162       int keylen;
 163       int yperr;
 164       if (new_start)
 165         yperr = yp_first (domain, "hosts.byname", &outkey, &keylen, &result,
 166                           &len);
 167       else
 168         yperr = yp_next (domain, "hosts.byname", oldkey, oldkeylen, &outkey,
 169                          &keylen, &result, &len);
 170
 171       if (__glibc_unlikely (yperr != YPERR_SUCCESS))
 172         {
 173           enum nss_status retval = yperr2nss (yperr);
 174
 175           switch (retval)
 176             {
 177             case NSS_STATUS_TRYAGAIN:
 178               *errnop = errno;
 179               *h_errnop = TRY_AGAIN;
 180               break;
 181             case NSS_STATUS_NOTFOUND:
 182               *h_errnop = HOST_NOT_FOUND;
 183               break;
 184             default:
 185               *h_errnop = NO_RECOVERY;
 186               break;
 187             }
 188           return retval;
 189         }
 190
 191       if (__glibc_unlikely ((size_t) (len + 1) > linebuflen))
 192         {
 193           free (result);
 194           *h_errnop = NETDB_INTERNAL;
 195           *errnop = ERANGE;
 196           return NSS_STATUS_TRYAGAIN;
 197         }
 198
 199       char *p = strncpy (data->linebuffer, result, len);
 200       data->linebuffer[len] = '\0';
 201       while (isspace (*p))
 202         ++p;
 203       free (result);
 204
 205       parse_res = parse_line (p, host, data, buflen, errnop, af, flags);
 206       if (__glibc_unlikely (parse_res == -1))
 207         {
 208           free (outkey);
 209           *h_errnop = NETDB_INTERNAL;
 210           *errnop = ERANGE;
 211           return NSS_STATUS_TRYAGAIN;
 212         }
 213       free (oldkey);
 214       oldkey = outkey;
 215       oldkeylen = keylen;
 216       new_start = 0;
 217     }
 218   while (!parse_res);
 219
 220   *h_errnop = NETDB_SUCCESS;
 221   return NSS_STATUS_SUCCESS;
 222 }
 223
 224
 225 enum nss_status
 226 _nss_nis_gethostent_r (struct hostent *host, char *buffer, size_t buflen,
 227                        int *errnop, int *h_errnop)
 228 {
 229   enum nss_status status;
 230
 231   __libc_lock_lock (lock);
 232
 233   status = internal_nis_gethostent_r (host, buffer, buflen, errnop, h_errnop,
 234                         (res_use_inet6 () ? AF_INET6 : AF_INET),
 235                         (res_use_inet6 () ? AI_V4MAPPED : 0 ));
 236
 237   __libc_lock_unlock (lock);
 238
 239   return status;
 240 }
 241
 242
 243 static enum nss_status
 244 internal_gethostbyname2_r (const char *name, int af, struct hostent *host,
 245                            char *buffer, size_t buflen, int *errnop,
 246                            int *h_errnop, int flags)
 247 {
 248   uintptr_t pad = -(uintptr_t) buffer % __alignof__ (struct parser_data);
 249   buffer += pad;
 250
 251   struct parser_data *data = (void *) buffer;
 252
 253   if (name == NULL)
 254     {
 255       *errnop = EINVAL;
 256       return NSS_STATUS_UNAVAIL;
 257     }
 258
 259   char *domain;
 260   if (yp_get_default_domain (&domain))
 261     return NSS_STATUS_UNAVAIL;
 262
 263   if (buflen < sizeof *data + 1 + pad)
 264     {
 265       *h_errnop = NETDB_INTERNAL;
 266       *errnop = ERANGE;
 267       return NSS_STATUS_TRYAGAIN;
 268     }
 269   buflen -= pad;
 270
 271   /* Convert name to lowercase.  */
 272   size_t namlen = strlen (name);
 273   /* Limit name length to the maximum size of an RPC packet.  */
 274   if (namlen > UDPMSGSIZE)
 275     {
 276       *errnop = ERANGE;
 277       return NSS_STATUS_UNAVAIL;
 278     }
 279
 280   char name2[namlen + 1];
 281   size_t i;
 282
 283   for (i = 0; i < namlen; ++i)
 284     name2[i] = tolower (name[i]);
 285   name2[i] = '\0';
 286
 287   char *result;
 288   int len;
 289   int yperr = yp_match (domain, "hosts.byname", name2, namlen, &result, &len);
 290
 291   if (__glibc_unlikely (yperr != YPERR_SUCCESS))
 292     {
 293       enum nss_status retval = yperr2nss (yperr);
 294
 295       if (retval == NSS_STATUS_TRYAGAIN)
 296         {
 297           *h_errnop = TRY_AGAIN;
 298           *errnop = errno;
 299         }
 300       if (retval == NSS_STATUS_NOTFOUND)
 301         *h_errnop = HOST_NOT_FOUND;
 302       return retval;
 303     }
 304
 305   const size_t linebuflen = buffer + buflen - data->linebuffer;
 306   if (__glibc_unlikely ((size_t) (len + 1) > linebuflen))
 307     {
 308       free (result);
 309       *h_errnop = NETDB_INTERNAL;
 310       *errnop = ERANGE;
 311       return NSS_STATUS_TRYAGAIN;
 312     }
 313
 314   char *p = strncpy (data->linebuffer, result, len);
 315   data->linebuffer[len] = '\0';
 316   while (isspace (*p))
 317     ++p;
 318   free (result);
 319
 320   int parse_res = parse_line (p, host, data, buflen, errnop, af, flags);
 321
 322   if (__glibc_unlikely (parse_res < 1 || host->h_addrtype != af))
 323     {
 324       if (parse_res == -1)
 325         {
 326           *h_errnop = NETDB_INTERNAL;
 327           return NSS_STATUS_TRYAGAIN;
 328         }
 329       else
 330         {
 331           *h_errnop = HOST_NOT_FOUND;
 332           return NSS_STATUS_NOTFOUND;
 333         }
 334     }
 335
 336   *h_errnop = NETDB_SUCCESS;
 337   return NSS_STATUS_SUCCESS;
 338 }
 339
 340
 341 enum nss_status
 342 _nss_nis_gethostbyname2_r (const char *name, int af, struct hostent *host,
 343                            char *buffer, size_t buflen, int *errnop,
 344                            int *h_errnop)
 345 {
 346   if (af != AF_INET && af != AF_INET6)
 347     {
 348       *h_errnop = HOST_NOT_FOUND;
 349       return NSS_STATUS_NOTFOUND;
 350     }
 351
 352   return internal_gethostbyname2_r (name, af, host, buffer, buflen, errnop,
 353                                     h_errnop,
 354                         (res_use_inet6 () ? AI_V4MAPPED : 0));
 355 }
 356
 357
 358 enum nss_status
 359 _nss_nis_gethostbyname_r (const char *name, struct hostent *host, char *buffer,
 360                           size_t buflen, int *errnop, int *h_errnop)
 361 {
 362   if (res_use_inet6 ())
 363     {
 364       enum nss_status status;
 365
 366       status = internal_gethostbyname2_r (name, AF_INET6, host, buffer, buflen,
 367                                           errnop, h_errnop, AI_V4MAPPED);
 368       if (status == NSS_STATUS_SUCCESS)
 369         return status;
 370     }
 371
 372   return internal_gethostbyname2_r (name, AF_INET, host, buffer, buflen,
 373                                     errnop, h_errnop, 0);
 374 }
 375
 376
 377 enum nss_status
 378 _nss_nis_gethostbyaddr_r (const void *addr, socklen_t addrlen, int af,
 379                           struct hostent *host, char *buffer, size_t buflen,
 380                           int *errnop, int *h_errnop)
 381 {
 382   char *domain;
 383   if (__glibc_unlikely (yp_get_default_domain (&domain)))
 384     return NSS_STATUS_UNAVAIL;
 385
 386   uintptr_t pad = -(uintptr_t) buffer % __alignof__ (struct parser_data);
 387   buffer += pad;
 388
 389   struct parser_data *data = (void *) buffer;
 390   if (__glibc_unlikely (buflen < sizeof *data + 1 + pad))
 391     {
 392       *errnop = ERANGE;
 393       *h_errnop = NETDB_INTERNAL;
 394       return NSS_STATUS_TRYAGAIN;
 395     }
 396   buflen -= pad;
 397
 398   char *buf = inet_ntoa (*(const struct in_addr *) addr);
 399
 400   char *result;
 401   int len;
 402   int yperr = yp_match (domain, "hosts.byaddr", buf, strlen (buf), &result,
 403                         &len);
 404
 405   if (__glibc_unlikely (yperr != YPERR_SUCCESS))
 406     {
 407       enum nss_status retval = yperr2nss (yperr);
 408
 409       if (retval == NSS_STATUS_TRYAGAIN)
 410         {
 411           *h_errnop = TRY_AGAIN;
 412           *errnop = errno;
 413         }
 414       else if (retval == NSS_STATUS_NOTFOUND)
 415         *h_errnop = HOST_NOT_FOUND;
 416
 417       return retval;
 418     }
 419
 420   const size_t linebuflen = buffer + buflen - data->linebuffer;
 421   if (__glibc_unlikely ((size_t) (len + 1) > linebuflen))
 422     {
 423       free (result);
 424       *errnop = ERANGE;
 425       *h_errnop = NETDB_INTERNAL;
 426       return NSS_STATUS_TRYAGAIN;
 427     }
 428
 429   char *p = strncpy (data->linebuffer, result, len);
 430   data->linebuffer[len] = '\0';
 431   while (isspace (*p))
 432     ++p;
 433   free (result);
 434
 435   int parse_res = parse_line (p, host, data, buflen, errnop, af,
 436                               (res_use_inet6 () ? AI_V4MAPPED : 0));
 437   if (__glibc_unlikely (parse_res < 1))
 438     {
 439       if (parse_res == -1)
 440         {
 441           *h_errnop = NETDB_INTERNAL;
 442           return NSS_STATUS_TRYAGAIN;
 443         }
 444       else
 445         {
 446           *h_errnop = HOST_NOT_FOUND;
 447           return NSS_STATUS_NOTFOUND;
 448         }
 449     }
 450
 451   *h_errnop = NETDB_SUCCESS;
 452   return NSS_STATUS_SUCCESS;
 453 }
 454
 455
 456 enum nss_status
 457 _nss_nis_gethostbyname4_r (const char *name, struct gaih_addrtuple **pat,
 458                            char *buffer, size_t buflen, int *errnop,
 459                            int *herrnop, int32_t *ttlp)
 460 {
 461   char *domain;
 462   if (yp_get_default_domain (&domain))
 463     {
 464       *herrnop = NO_DATA;
 465       return NSS_STATUS_UNAVAIL;
 466     }
 467
 468   /* Convert name to lowercase.  */
 469   size_t namlen = strlen (name);
 470   /* Limit name length to the maximum size of an RPC packet.  */
 471   if (namlen > UDPMSGSIZE)
 472     {
 473       *errnop = ERANGE;
 474       return NSS_STATUS_UNAVAIL;
 475     }
 476
 477   char name2[namlen + 1];
 478   size_t i;
 479
 480   for (i = 0; i < namlen; ++i)
 481     name2[i] = tolower (name[i]);
 482   name2[i] = '\0';
 483
 484   char *result;
 485   int len;
 486   int yperr = yp_match (domain, "hosts.byname", name2, namlen, &result, &len);
 487
 488   if (__glibc_unlikely (yperr != YPERR_SUCCESS))
 489     {
 490       enum nss_status retval = yperr2nss (yperr);
 491
 492       if (retval == NSS_STATUS_TRYAGAIN)
 493         {
 494           *herrnop = TRY_AGAIN;
 495           *errnop = errno;
 496         }
 497       if (retval == NSS_STATUS_NOTFOUND)
 498         *herrnop = HOST_NOT_FOUND;
 499       return retval;
 500     }
 501
 502   if (*pat == NULL)
 503     {
 504       uintptr_t pad = (-(uintptr_t) buffer
 505                        % __alignof__ (struct gaih_addrtuple));
 506       buffer += pad;
 507       buflen = buflen > pad ? buflen - pad : 0;
 508
 509       if (__glibc_unlikely (buflen < sizeof (struct gaih_addrtuple)))
 510         {
 511         erange:
 512           free (result);
 513           *errnop = ERANGE;
 514           *herrnop = NETDB_INTERNAL;
 515           return NSS_STATUS_TRYAGAIN;
 516         }
 517
 518       *pat = (struct gaih_addrtuple *) buffer;
 519       buffer += sizeof (struct gaih_addrtuple);
 520       buflen -= sizeof (struct gaih_addrtuple);
 521     }
 522
 523   uintptr_t pad = -(uintptr_t) buffer % __alignof__ (struct parser_data);
 524   buffer += pad;
 525
 526   struct parser_data *data = (void *) buffer;
 527
 528   if (__glibc_unlikely (buflen < sizeof *data + 1 + pad))
 529     goto erange;
 530   buflen -= pad;
 531
 532   struct hostent host;
 533   int parse_res = parse_line (result, &host, data, buflen, errnop, AF_UNSPEC,
 534                               0);
 535   if (__glibc_unlikely (parse_res < 1))
 536     {
 537       if (parse_res == -1)
 538         {
 539           *herrnop = NETDB_INTERNAL;
 540           return NSS_STATUS_TRYAGAIN;
 541         }
 542       else
 543         {
 544           *herrnop = HOST_NOT_FOUND;
 545           return NSS_STATUS_NOTFOUND;
 546         }
 547     }
 548
 549   (*pat)->next = NULL;
 550   (*pat)->family = host.h_addrtype;
 551   memcpy ((*pat)->addr, host.h_addr_list[0], host.h_length);
 552   (*pat)->scopeid = 0;
 553   assert (host.h_addr_list[1] == NULL);
 554
 555   /* Undo the alignment for parser_data.  */
 556   buffer -= pad;
 557   buflen += pad;
 558
 559   size_t h_name_len = strlen (host.h_name) + 1;
 560   if (h_name_len >= buflen)
 561     goto erange;
 562   (*pat)->name = memcpy (buffer, host.h_name, h_name_len);
 563
 564   free (result);
 565
 566   return NSS_STATUS_SUCCESS;
 567 }