nss/digits_dots.c

   1 /* Copyright (C) 1997-2015 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by H.J. Lu <hjl@gnu.ai.mit.edu>, 1997.
   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 <errno.h>
  21 #include <string.h>
  22 #include <stdlib.h>
  23 #include <ctype.h>
  24 #include <wctype.h>
  25 #include <resolv.h>
  26 #include <netdb.h>
  27 #include <arpa/inet.h>
  28 #include "nsswitch.h"
  29
  30 #ifdef USE_NSCD
  31 # define inet_aton __inet_aton
  32 # include <nscd/nscd_proto.h>
  33 #endif
  34
  35 int
  36 __nss_hostname_digits_dots (const char *name, struct hostent *resbuf,
  37                             char **buffer, size_t *buffer_size,
  38                             size_t buflen, struct hostent **result,
  39                             enum nss_status *status, int af, int *h_errnop)
  40 {
  41   int save;
  42
  43   /* We have to test for the use of IPv6 which can only be done by
  44      examining `_res'.  */
  45   if (__res_maybe_init (&_res, 0) == -1)
  46     {
  47       if (h_errnop)
  48         *h_errnop = NETDB_INTERNAL;
  49       if (buffer_size == NULL)
  50         *status = NSS_STATUS_TRYAGAIN;
  51       else
  52         *result = NULL;
  53       return -1;
  54     }
  55
  56   /*
  57    * disallow names consisting only of digits/dots, unless
  58    * they end in a dot.
  59    */
  60   if (isdigit (name[0]) || isxdigit (name[0]) || name[0] == ':')
  61     {
  62       const char *cp;
  63       char *hostname;
  64       typedef unsigned char host_addr_t[16];
  65       host_addr_t *host_addr;
  66       typedef char *host_addr_list_t[2];
  67       host_addr_list_t *h_addr_ptrs;
  68       char **h_alias_ptr;
  69       size_t size_needed;
  70       int addr_size;
  71
  72       switch (af)
  73         {
  74         case AF_INET:
  75           addr_size = INADDRSZ;
  76           break;
  77
  78         case AF_INET6:
  79           addr_size = IN6ADDRSZ;
  80           break;
  81
  82         default:
  83           af = (_res.options & RES_USE_INET6) ? AF_INET6 : AF_INET;
  84           addr_size = af == AF_INET6 ? IN6ADDRSZ : INADDRSZ;
  85           break;
  86         }
  87
  88       size_needed = (sizeof (*host_addr)
  89                      + sizeof (*h_addr_ptrs)
  90                      + sizeof (*h_alias_ptr) + strlen (name) + 1);
  91
  92       if (buffer_size == NULL)
  93         {
  94           if (buflen < size_needed)
  95             {
  96               *status = NSS_STATUS_TRYAGAIN;
  97               if (h_errnop != NULL)
  98                 *h_errnop = NETDB_INTERNAL;
  99               __set_errno (ERANGE);
 100               goto done;
 101             }
 102         }
 103       else if (buffer_size != NULL && *buffer_size < size_needed)
 104         {
 105           char *new_buf;
 106           *buffer_size = size_needed;
 107           new_buf = (char *) realloc (*buffer, *buffer_size);
 108
 109           if (new_buf == NULL)
 110             {
 111               save = errno;
 112               free (*buffer);
 113               *buffer = NULL;
 114               *buffer_size = 0;
 115               __set_errno (save);
 116               if (h_errnop != NULL)
 117                 *h_errnop = NETDB_INTERNAL;
 118               *result = NULL;
 119               goto done;
 120             }
 121           *buffer = new_buf;
 122         }
 123
 124       memset (*buffer, '\0', size_needed);
 125
 126       host_addr = (host_addr_t *) *buffer;
 127       h_addr_ptrs = (host_addr_list_t *)
 128         ((char *) host_addr + sizeof (*host_addr));
 129       h_alias_ptr = (char **) ((char *) h_addr_ptrs + sizeof (*h_addr_ptrs));
 130       hostname = (char *) h_alias_ptr + sizeof (*h_alias_ptr);
 131
 132       if (isdigit (name[0]))
 133         {
 134           for (cp = name;; ++cp)
 135             {
 136               if (*cp == '\0')
 137                 {
 138                   int ok;
 139
 140                   if (*--cp == '.')
 141                     break;
 142
 143                   /* All-numeric, no dot at the end. Fake up a hostent as if
 144                      we'd actually done a lookup.  What if someone types
 145                      255.255.255.255?  The test below will succeed
 146                      spuriously... ???  */
 147                   if (af == AF_INET)
 148                     ok = __inet_aton (name, (struct in_addr *) host_addr);
 149                   else
 150                     {
 151                       assert (af == AF_INET6);
 152                       ok = inet_pton (af, name, host_addr) > 0;
 153                     }
 154                   if (! ok)
 155                     {
 156                       *h_errnop = HOST_NOT_FOUND;
 157                       if (buffer_size == NULL)
 158                         *status = NSS_STATUS_NOTFOUND;
 159                       else
 160                         *result = NULL;
 161                       goto done;
 162                     }
 163
 164                   resbuf->h_name = strcpy (hostname, name);
 165                   h_alias_ptr[0] = NULL;
 166                   resbuf->h_aliases = h_alias_ptr;
 167                   (*h_addr_ptrs)[0] = (char *) host_addr;
 168                   (*h_addr_ptrs)[1] = NULL;
 169                   resbuf->h_addr_list = *h_addr_ptrs;
 170                   if (af == AF_INET && (_res.options & RES_USE_INET6))
 171                     {
 172                       /* We need to change the IP v4 address into the
 173                          IP v6 address.  */
 174                       char tmp[INADDRSZ];
 175                       char *p = (char *) host_addr;
 176                       int i;
 177
 178                       /* Save a copy of the IP v4 address. */
 179                       memcpy (tmp, host_addr, INADDRSZ);
 180                       /* Mark this ipv6 addr as a mapped ipv4. */
 181                       for (i = 0; i < 10; i++)
 182                         *p++ = 0x00;
 183                       *p++ = 0xff;
 184                       *p++ = 0xff;
 185                       /* Copy the IP v4 address. */
 186                       memcpy (p, tmp, INADDRSZ);
 187                       resbuf->h_addrtype = AF_INET6;
 188                       resbuf->h_length = IN6ADDRSZ;
 189                     }
 190                   else
 191                     {
 192                       resbuf->h_addrtype = af;
 193                       resbuf->h_length = addr_size;
 194                     }
 195                   if (h_errnop != NULL)
 196                     *h_errnop = NETDB_SUCCESS;
 197                   if (buffer_size == NULL)
 198                     *status = NSS_STATUS_SUCCESS;
 199                   else
 200                     *result = resbuf;
 201                   goto done;
 202                 }
 203
 204               if (!isdigit (*cp) && *cp != '.')
 205                 break;
 206             }
 207         }
 208
 209       if ((isxdigit (name[0]) && strchr (name, ':') != NULL) || name[0] == ':')
 210         {
 211           switch (af)
 212             {
 213             default:
 214               af = (_res.options & RES_USE_INET6) ? AF_INET6 : AF_INET;
 215               if (af == AF_INET6)
 216                 {
 217                   addr_size = IN6ADDRSZ;
 218                   break;
 219                 }
 220               /* FALLTHROUGH */
 221
 222             case AF_INET:
 223               /* This is not possible.  We cannot represent an IPv6 address
 224                  in an `struct in_addr' variable.  */
 225               *h_errnop = HOST_NOT_FOUND;
 226               if (buffer_size == NULL)
 227                 *status = NSS_STATUS_NOTFOUND;
 228               else
 229                 *result = NULL;
 230               goto done;
 231
 232             case AF_INET6:
 233               addr_size = IN6ADDRSZ;
 234               break;
 235             }
 236
 237           for (cp = name;; ++cp)
 238             {
 239               if (!*cp)
 240                 {
 241                   if (*--cp == '.')
 242                     break;
 243
 244                   /* All-IPv6-legal, no dot at the end. Fake up a
 245                      hostent as if we'd actually done a lookup.  */
 246                   if (inet_pton (AF_INET6, name, host_addr) <= 0)
 247                     {
 248                       *h_errnop = HOST_NOT_FOUND;
 249                       if (buffer_size == NULL)
 250                         *status = NSS_STATUS_NOTFOUND;
 251                       else
 252                         *result = NULL;
 253                       goto done;
 254                     }
 255
 256                   resbuf->h_name = strcpy (hostname, name);
 257                   h_alias_ptr[0] = NULL;
 258                   resbuf->h_aliases = h_alias_ptr;
 259                   (*h_addr_ptrs)[0] = (char *) host_addr;
 260                   (*h_addr_ptrs)[1] = (char *) 0;
 261                   resbuf->h_addr_list = *h_addr_ptrs;
 262                   resbuf->h_addrtype = AF_INET6;
 263                   resbuf->h_length = addr_size;
 264                   *h_errnop = NETDB_SUCCESS;
 265                   if (buffer_size == NULL)
 266                     *status = NSS_STATUS_SUCCESS;
 267                   else
 268                     *result = resbuf;
 269                   goto done;
 270                 }
 271
 272               if (!isxdigit (*cp) && *cp != ':' && *cp != '.')
 273                 break;
 274             }
 275         }
 276     }
 277
 278   return 0;
 279
 280 done:
 281   return 1;
 282 }
 283 libc_hidden_def (__nss_hostname_digits_dots)