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/* Test the behavior of the trust-ad option.
Copyright (C) 2019-2023 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#include <resolv.h>
#include <stdlib.h>
#include <string.h>
#include <support/check.h>
#include <support/check_nss.h>
#include <support/resolv_test.h>
#include <support/support.h>
/* This controls properties of the response. volatile because
__res_send is incorrectly declared as __THROW. */
static volatile unsigned char response_number;
static volatile bool response_ad_bit;
static volatile bool query_ad_bit;
static void
response (const struct resolv_response_context *ctx,
struct resolv_response_builder *b,
const char *qname, uint16_t qclass, uint16_t qtype)
{
TEST_COMPARE (qclass, C_IN);
TEST_COMPARE (qtype, T_A);
TEST_COMPARE_STRING (qname, "www.example");
HEADER header;
memcpy (&header, ctx->query_buffer, sizeof (header));
TEST_COMPARE (header.ad, query_ad_bit);
struct resolv_response_flags flags = { .ad = response_ad_bit, };
resolv_response_init (b, flags);
resolv_response_add_question (b, qname, qclass, qtype);
resolv_response_section (b, ns_s_an);
resolv_response_open_record (b, qname, qclass, T_A, 0x12345678);
char addr[4] = { 192, 0, 2, response_number };
resolv_response_add_data (b, addr, sizeof (addr));
resolv_response_close_record (b);
}
static void
check_answer (const unsigned char *buffer, size_t buffer_length,
bool expected_ad)
{
HEADER header;
TEST_VERIFY (buffer_length > sizeof (header));
memcpy (&header, buffer, sizeof (header));
TEST_COMPARE (0, header.aa);
TEST_COMPARE (expected_ad, header.ad);
TEST_COMPARE (0, header.opcode);
TEST_COMPARE (1, header.qr);
TEST_COMPARE (0, header.rcode);
TEST_COMPARE (1, header.rd);
TEST_COMPARE (0, header.tc);
TEST_COMPARE (1, ntohs (header.qdcount));
TEST_COMPARE (1, ntohs (header.ancount));
TEST_COMPARE (0, ntohs (header.nscount));
TEST_COMPARE (0, ntohs (header.arcount));
char *description = xasprintf ("response=%d ad=%d",
response_number, expected_ad);
char *expected = xasprintf ("name: www.example\n"
"address: 192.0.2.%d\n", response_number);
check_dns_packet (description, buffer, buffer_length, expected);
free (expected);
free (description);
}
static int
do_test (void)
{
struct resolv_test *aux = resolv_test_start
((struct resolv_redirect_config)
{
.response_callback = response,
});
/* By default, the resolver is not trusted, and the AD bit is
cleared. */
static const unsigned char hand_crafted_query[] =
{
10, 11, /* Transaction ID. */
1, 0x20, /* Query with RD, AD flags. */
0, 1, /* One question. */
0, 0, 0, 0, 0, 0, /* The other sections are empty. */
3, 'w', 'w', 'w', 7, 'e', 'x', 'a', 'm', 'p', 'l', 'e', 0,
0, T_A, /* A query. */
0, 1, /* Class IN. */
};
++response_number;
response_ad_bit = false;
unsigned char buffer[512];
memset (buffer, 255, sizeof (buffer));
query_ad_bit = true;
int ret = res_send (hand_crafted_query, sizeof (hand_crafted_query),
buffer, sizeof (buffer));
TEST_VERIFY (ret > 0);
check_answer (buffer, ret, false);
++response_number;
memset (buffer, 255, sizeof (buffer));
query_ad_bit = false;
ret = res_query ("www.example", C_IN, T_A, buffer, sizeof (buffer));
TEST_VERIFY (ret > 0);
check_answer (buffer, ret, false);
response_ad_bit = true;
response_ad_bit = true;
++response_number;
query_ad_bit = true;
ret = res_send (hand_crafted_query, sizeof (hand_crafted_query),
buffer, sizeof (buffer));
TEST_VERIFY (ret > 0);
check_answer (buffer, ret, false);
++response_number;
memset (buffer, 255, sizeof (buffer));
query_ad_bit = false;
ret = res_query ("www.example", C_IN, T_A, buffer, sizeof (buffer));
TEST_VERIFY (ret > 0);
check_answer (buffer, ret, false);
/* No AD bit set in generated queries. */
memset (buffer, 255, sizeof (buffer));
ret = res_mkquery (QUERY, "www.example", C_IN, T_A,
(const unsigned char *) "", 0, NULL,
buffer, sizeof (buffer));
HEADER header;
memcpy (&header, buffer, sizeof (header));
TEST_VERIFY (!header.ad);
/* With RES_TRUSTAD, the AD bit is passed through if it set in the
response. It is also included in queries. */
_res.options |= RES_TRUSTAD;
query_ad_bit = true;
response_ad_bit = false;
++response_number;
memset (buffer, 255, sizeof (buffer));
ret = res_send (hand_crafted_query, sizeof (hand_crafted_query),
buffer, sizeof (buffer));
TEST_VERIFY (ret > 0);
check_answer (buffer, ret, false);
++response_number;
memset (buffer, 255, sizeof (buffer));
ret = res_query ("www.example", C_IN, T_A, buffer, sizeof (buffer));
TEST_VERIFY (ret > 0);
check_answer (buffer, ret, false);
response_ad_bit = true;
++response_number;
memset (buffer, 0, sizeof (buffer));
ret = res_send (hand_crafted_query, sizeof (hand_crafted_query),
buffer, sizeof (buffer));
TEST_VERIFY (ret > 0);
check_answer (buffer, ret, true);
++response_number;
memset (buffer, 0, sizeof (buffer));
ret = res_query ("www.example", C_IN, T_A, buffer, sizeof (buffer));
TEST_VERIFY (ret > 0);
check_answer (buffer, ret, true);
/* AD bit set in generated queries. */
memset (buffer, 0, sizeof (buffer));
ret = res_mkquery (QUERY, "www.example", C_IN, T_A,
(const unsigned char *) "", 0, NULL,
buffer, sizeof (buffer));
memcpy (&header, buffer, sizeof (header));
TEST_VERIFY (header.ad);
resolv_test_end (aux);
return 0;
}
#include <support/test-driver.c>
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