resolv/tst-resolv-search.c

   1 /* Test search/default domain name behavior.
   2    Copyright (C) 2016 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   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 <resolv.h>
  20 #include <string.h>
  21 #include <support/check.h>
  22 #include <support/check_nss.h>
  23 #include <support/resolv_test.h>
  24 #include <support/support.h>
  25 #include <support/xmemstream.h>
  26
  27 struct item
  28 {
  29   const char *name;
  30   int response;
  31 };
  32
  33 const struct item items[] =
  34   {
  35     {"hostname.usersys.example.com", 1},
  36     {"hostname.corp.example.com", 1},
  37     {"hostname.example.com", 1},
  38
  39     {"mail.corp.example.com", 1},
  40     {"mail.example.com", 1},
  41
  42     {"file.corp.example.com", 2},
  43     {"file.corp", 1},
  44     {"file.example.com", 1},
  45     {"servfail-usersys.usersys.example.com", -ns_r_servfail},
  46     {"servfail-usersys.corp.example.com", 1},
  47     {"servfail-usersys.example.com", 1},
  48     {"servfail-corp.usersys.example.com", 1},
  49     {"servfail-corp.corp.example.com", -ns_r_servfail},
  50     {"servfail-corp.example.com", 1},
  51     {"www.example.com", 1},
  52     {"large.example.com", 200},
  53
  54     /* Test query amplification with a SERVFAIL response combined with
  55        a large RRset.  */
  56     {"large-servfail.usersys.example.com", -ns_r_servfail},
  57     {"large-servfail.example.com", 2000},
  58     {}
  59   };
  60
  61 enum
  62   {
  63     name_not_found = -1,
  64     name_no_data = -2
  65   };
  66
  67 static int
  68 find_name (const char *name)
  69 {
  70   for (int i = 0; items[i].name != NULL; ++i)
  71     {
  72       if (strcmp (name, items[i].name) == 0)
  73         return i;
  74     }
  75   if (strcmp (name, "example.com") == 0
  76       || strcmp (name, "usersys.example.com") == 0
  77       || strcmp (name, "corp.example.com") == 0)
  78     return name_no_data;
  79   return name_not_found;
  80 }
  81
  82 static int rcode_override_server_index = -1;
  83 static int rcode_override;
  84
  85 static void
  86 response (const struct resolv_response_context *ctx,
  87           struct resolv_response_builder *b,
  88           const char *qname, uint16_t qclass, uint16_t qtype)
  89 {
  90   if (ctx->server_index == rcode_override_server_index)
  91     {
  92       struct resolv_response_flags flags = {.rcode = rcode_override};
  93       resolv_response_init (b, flags);
  94       resolv_response_add_question (b, qname, qclass, qtype);
  95       return;
  96     }
  97
  98   int index = find_name (qname);
  99   struct resolv_response_flags flags = {};
 100   if (index == name_not_found)
 101     flags.rcode = ns_r_nxdomain;
 102   else if (index >= 0 && items[index].response < 0)
 103     flags.rcode = -items[index].response;
 104   else if (index >= 0 && items[index].response > 5 && !ctx->tcp)
 105     /* Force TCP if more than 5 addresses where requested.  */
 106     flags.tc = true;
 107   resolv_response_init (b, flags);
 108   resolv_response_add_question (b, qname, qclass, qtype);
 109
 110   if (flags.tc || index < 0 || items[index].response < 0)
 111     return;
 112
 113   resolv_response_section (b, ns_s_an);
 114
 115   for (int i = 0; i < items[index].response; ++i)
 116     {
 117       resolv_response_open_record (b, qname, qclass, qtype, 0);
 118
 119       switch (qtype)
 120         {
 121         case T_A:
 122           {
 123             char addr[4] = {10, index, i >> 8, i};
 124             resolv_response_add_data (b, addr, sizeof (addr));
 125           }
 126           break;
 127         case T_AAAA:
 128           {
 129             char addr[16]
 130               = {0x20, 0x01, 0xd, 0xb8, 0, 0, 0, 0, 0, 0, 0, 0,
 131                  0, index + 1, (i + 1) >> 8, i + 1};
 132             resolv_response_add_data (b, addr, sizeof (addr));
 133           }
 134           break;
 135         default:
 136           support_record_failure ();
 137           printf ("error: unexpected QTYPE: %s/%u/%u\n",
 138                   qname, qclass, qtype);
 139         }
 140       resolv_response_close_record (b);
 141     }
 142 }
 143
 144 enum output_format
 145   {
 146     format_get, format_gai
 147   };
 148
 149 static void
 150 format_expected_1 (FILE *out, int family, enum output_format format, int index)
 151 {
 152   for (int i = 0; i < items[index].response; ++i)
 153     {
 154       char address[200];
 155       switch (family)
 156         {
 157         case AF_INET:
 158           snprintf (address, sizeof (address), "10.%d.%d.%d",
 159                     index, (i >> 8) & 0xff, i & 0xff);
 160           break;
 161         case AF_INET6:
 162           snprintf (address, sizeof (address), "2001:db8::%x:%x",
 163                     index + 1, i + 1);
 164           break;
 165         default:
 166           FAIL_EXIT1 ("unreachable");
 167         }
 168
 169       switch (format)
 170         {
 171         case format_get:
 172           fprintf (out, "address: %s\n", address);
 173           break;
 174         case format_gai:
 175           fprintf (out, "address: STREAM/TCP %s 80\n", address);
 176         }
 177     }
 178 }
 179
 180 static char *
 181 format_expected (const char *fqdn, int family, enum output_format format)
 182 {
 183   int index = find_name (fqdn);
 184   TEST_VERIFY_EXIT (index >= 0);
 185   struct xmemstream stream;
 186   xopen_memstream (&stream);
 187
 188   TEST_VERIFY_EXIT (items[index].response >= 0);
 189   if (format == format_get)
 190     fprintf (stream.out, "name: %s\n", items[index].name);
 191   if (family == AF_INET || family == AF_UNSPEC)
 192     format_expected_1 (stream.out, AF_INET, format, index);
 193   if (family == AF_INET6 || family == AF_UNSPEC)
 194     format_expected_1 (stream.out, AF_INET6, format, index);
 195
 196   xfclose_memstream (&stream);
 197   return stream.buffer;
 198 }
 199
 200 static void
 201 do_get (const char *name, const char *fqdn, int family)
 202 {
 203   char *expected = format_expected (fqdn, family, format_get);
 204   if (family == AF_INET)
 205     {
 206       char *query = xasprintf ("gethostbyname (\"%s\")", name);
 207       check_hostent (query, gethostbyname (name), expected);
 208       free (query);
 209     }
 210   char *query = xasprintf ("gethostbyname2 (\"%s\", %d)", name, family);
 211   check_hostent (query, gethostbyname2 (name, family), expected);
 212
 213   /* Test res_search.  */
 214   int qtype;
 215   switch (family)
 216     {
 217     case AF_INET:
 218       qtype = T_A;
 219       break;
 220     case AF_INET6:
 221       qtype = T_AAAA;
 222       break;
 223     default:
 224       qtype = -1;
 225     }
 226   if (qtype >= 0)
 227     {
 228       int sz = 512;
 229       unsigned char *response = xmalloc (sz);
 230       int ret = res_search (name, C_IN, qtype, response, sz);
 231       TEST_VERIFY_EXIT (ret >= 0);
 232       if (ret > sz)
 233         {
 234           /* Truncation.  Retry with a larger buffer.  */
 235           sz = 65535;
 236           unsigned char *newptr = xrealloc (response, sz);
 237           response = newptr;
 238
 239           ret = res_search (name, C_IN, qtype, response, sz);
 240           TEST_VERIFY_EXIT (ret >= 0);
 241           TEST_VERIFY_EXIT (ret < sz);
 242         }
 243       check_dns_packet (query, response, ret, expected);
 244       free (response);
 245     }
 246
 247   free (query);
 248   free (expected);
 249 }
 250
 251 static void
 252 do_gai (const char *name, const char *fqdn, int family)
 253 {
 254   struct addrinfo hints =
 255     {
 256       .ai_family = family,
 257       .ai_protocol = IPPROTO_TCP,
 258       .ai_socktype = SOCK_STREAM
 259     };
 260   struct addrinfo *ai;
 261   char *query = xasprintf ("%s:80 [%d]", name, family);
 262   int ret = getaddrinfo (name, "80", &hints, &ai);
 263   char *expected = format_expected (fqdn, family, format_gai);
 264   check_addrinfo (query, ai, ret, expected);
 265   if (ret == 0)
 266     freeaddrinfo (ai);
 267   free (expected);
 268   free (query);
 269 }
 270
 271 static void
 272 do_both (const char *name, const char *fqdn)
 273 {
 274   do_get (name, fqdn, AF_INET);
 275   do_get (name, fqdn, AF_INET6);
 276   do_gai (name, fqdn, AF_INET);
 277   do_gai (name, fqdn, AF_INET6);
 278   do_gai (name, fqdn, AF_UNSPEC);
 279 }
 280
 281 static void
 282 do_test_all (bool unconnectable_server)
 283 {
 284   struct resolv_redirect_config config =
 285     {
 286       .response_callback = response,
 287       .search = {"usersys.example.com", "corp.example.com", "example.com"},
 288     };
 289   struct resolv_test *obj = resolv_test_start (config);
 290
 291   if (unconnectable_server)
 292     {
 293       /* 255.255.255.255 results in an immediate connect failure.  The
 294          next server will supply the answer instead.  This is a
 295          triggering condition for bug 19791.  */
 296       _res.nsaddr_list[0].sin_addr.s_addr = -1;
 297       _res.nsaddr_list[0].sin_port = htons (53);
 298     }
 299
 300   do_both ("file", "file.corp.example.com");
 301   do_both ("www", "www.example.com");
 302   do_both ("servfail-usersys", "servfail-usersys.corp.example.com");
 303   do_both ("servfail-corp", "servfail-corp.usersys.example.com");
 304   do_both ("large", "large.example.com");
 305   do_both ("large-servfail", "large-servfail.example.com");
 306   do_both ("file.corp", "file.corp");
 307
 308   /* Check that SERVFAIL and REFUSED responses do not alter the search
 309      path resolution.  */
 310   rcode_override_server_index = 0;
 311   rcode_override = ns_r_servfail;
 312   do_both ("hostname", "hostname.usersys.example.com");
 313   do_both ("large", "large.example.com");
 314   do_both ("large-servfail", "large-servfail.example.com");
 315   rcode_override = ns_r_refused;
 316   do_both ("hostname", "hostname.usersys.example.com");
 317   do_both ("large", "large.example.com");
 318   do_both ("large-servfail", "large-servfail.example.com");
 319   /* Likewise, but with an NXDOMAIN for the first search path
 320      entry.  */
 321   rcode_override = ns_r_servfail;
 322   do_both ("mail", "mail.corp.example.com");
 323   rcode_override = ns_r_refused;
 324   do_both ("mail", "mail.corp.example.com");
 325   /* Likewise, but with ndots handling.  */
 326   rcode_override = ns_r_servfail;
 327   do_both ("file.corp", "file.corp");
 328   rcode_override = ns_r_refused;
 329   do_both ("file.corp", "file.corp");
 330
 331   resolv_test_end (obj);
 332 }
 333
 334 static int
 335 do_test (void)
 336 {
 337   for (int unconnectable_server = 0; unconnectable_server < 2;
 338        ++unconnectable_server)
 339     do_test_all (unconnectable_server);
 340   return 0;
 341 }
 342
 343 #include <support/test-driver.c>