resolv/tst-resolv-binary.c

   1 /* Test handling of binary domain names with res_send.
   2    Copyright (C) 2018-2023 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    <https://www.gnu.org/licenses/>.  */
  18
  19 #include <resolv.h>
  20 #include <string.h>
  21 #include <support/check.h>
  22 #include <support/resolv_test.h>
  23
  24 static void
  25 response (const struct resolv_response_context *ctx,
  26           struct resolv_response_builder *b,
  27           const char *qname, uint16_t qclass, uint16_t qtype)
  28 {
  29   TEST_COMPARE (qclass, C_IN);
  30   TEST_COMPARE (qtype, T_TXT);
  31   TEST_VERIFY (strlen (qname) <= 255);
  32
  33   struct resolv_response_flags flags = { 0 };
  34   resolv_response_init (b, flags);
  35   resolv_response_add_question (b, qname, qclass, qtype);
  36   resolv_response_section (b, ns_s_an);
  37   resolv_response_open_record (b, qname, qclass, T_TXT, 0x12345678);
  38   unsigned char qnamelen = strlen (qname);
  39   resolv_response_add_data (b, &qnamelen, 1);
  40   resolv_response_add_data (b, qname, qnamelen);
  41   resolv_response_close_record (b);
  42 }
  43
  44 static int
  45 do_test (void)
  46 {
  47   struct resolv_test *aux = resolv_test_start
  48     ((struct resolv_redirect_config)
  49      {
  50        .response_callback = response,
  51      });
  52
  53   for (int b = 0; b <= 255; ++b)
  54     {
  55       unsigned char query[] =
  56         {
  57           b, b,                 /* Transaction ID.  */
  58           1, 0,                 /* Query with RD flag.  */
  59           0, 1,                 /* One question.  */
  60           0, 0, 0, 0, 0, 0,     /* The other sections are empty.  */
  61           1, b, 7, 'e', 'x', 'a', 'm', 'p', 'l', 'e', 0,
  62           0, T_TXT,             /* TXT query.  */
  63           0, 1,                 /* Class IN.  */
  64         };
  65       unsigned char response[512];
  66       int ret = res_send (query, sizeof (query), response, sizeof (response));
  67
  68       char expected_name[20];
  69       /* The name is uncompressed in the query, so we can reference it
  70          directly.  */
  71       TEST_VERIFY_EXIT (ns_name_ntop (query + 12, expected_name,
  72                                       sizeof (expected_name)) >= 0);
  73       TEST_COMPARE (ret,
  74                     (ssize_t) sizeof (query)
  75                     + 2             /* Compression reference.  */
  76                     + 2 + 2 + 4 + 2 /* Type, class, TTL, RDATA length.  */
  77                     + 1             /* Pascal-style string length.  */
  78                     + strlen (expected_name));
  79
  80       /* Mark as answer, with recursion available, and one answer.  */
  81       query[2] = 0x81;
  82       query[3] = 0x80;
  83       query[7] = 1;
  84
  85       /* Prefix of the response must match the query.  */
  86       TEST_COMPARE (memcmp (response, query, sizeof (query)), 0);
  87
  88       /* The actual answer follows, starting with the compression
  89          reference.  */
  90       unsigned char *p = response + sizeof (query);
  91       TEST_COMPARE (*p++, 0xc0);
  92       TEST_COMPARE (*p++, 0x0c);
  93
  94       /* Type and class.  */
  95       TEST_COMPARE (*p++, 0);
  96       TEST_COMPARE (*p++, T_TXT);
  97       TEST_COMPARE (*p++, 0);
  98       TEST_COMPARE (*p++, C_IN);
  99
 100       /* TTL.  */
 101       TEST_COMPARE (*p++, 0x12);
 102       TEST_COMPARE (*p++, 0x34);
 103       TEST_COMPARE (*p++, 0x56);
 104       TEST_COMPARE (*p++, 0x78);
 105
 106       /* RDATA length.  */
 107       TEST_COMPARE (*p++, 0);
 108       TEST_COMPARE (*p++, 1 + strlen (expected_name));
 109
 110       /* RDATA.  */
 111       TEST_COMPARE (*p++, strlen (expected_name));
 112       TEST_COMPARE (memcmp (p, expected_name, strlen (expected_name)), 0);
 113     }
 114
 115   resolv_test_end (aux);
 116
 117   return 0;
 118 }
 119
 120 #include <support/test-driver.c>