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resolv: Make RES_ROTATE start with a random name server [BZ #19570]
Do not copy the actual name server addresses to rotate them. Use a global rotation offset instead.
This commit is contained in:
Florian Weimer
263
resolv/tst-resolv-rotate.c
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263
resolv/tst-resolv-rotate.c
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@@ -0,0 +1,263 @@
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/* Check that RES_ROTATE works with few nameserver entries (bug 13028).
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Copyright (C) 2017 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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#include <netdb.h>
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#include <resolv.h>
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#include <stdlib.h>
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#include <string.h>
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#include <support/check.h>
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#include <support/check_nss.h>
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#include <support/resolv_test.h>
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#include <support/test-driver.h>
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static volatile int drop_server = -1;
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static volatile unsigned int query_counts[resolv_max_test_servers];
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static const char address_ipv4[4] = {192, 0, 2, 1};
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static const char address_ipv6[16]
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= {0x20, 0x01, 0xd, 0xb8, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1};
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static void
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response (const struct resolv_response_context *ctx,
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struct resolv_response_builder *b,
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const char *qname, uint16_t qclass, uint16_t qtype)
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{
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if (ctx->server_index == drop_server)
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{
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resolv_response_drop (b);
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resolv_response_close (b);
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return;
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}
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bool force_tcp = strncmp (qname, "2.", 2) == 0;
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struct resolv_response_flags flags = {.tc = force_tcp && !ctx->tcp};
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resolv_response_init (b, flags);
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resolv_response_add_question (b, qname, qclass, qtype);
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if (flags.tc)
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return;
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TEST_VERIFY_EXIT (ctx->server_index < resolv_max_test_servers);
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++query_counts[ctx->server_index];
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resolv_response_section (b, ns_s_an);
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resolv_response_open_record (b, qname, qclass, qtype, 0);
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switch (qtype)
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{
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case T_A:
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{
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char addr[sizeof (address_ipv4)];
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memcpy (addr, address_ipv4, sizeof (address_ipv4));
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addr[3] = 1 + ctx->tcp;
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resolv_response_add_data (b, addr, sizeof (addr));
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}
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break;
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case T_AAAA:
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{
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char addr[sizeof (address_ipv6)];
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memcpy (addr, address_ipv6, sizeof (address_ipv6));
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addr[15] = 1 + ctx->tcp;
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resolv_response_add_data (b, addr, sizeof (addr));
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}
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break;
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case T_PTR:
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if (force_tcp)
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resolv_response_add_name (b, "2.host.example");
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else
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resolv_response_add_name (b, "host.example");
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break;
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default:
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FAIL_EXIT1 ("unexpected QTYPE: %s/%u/%u", qname, qclass, qtype);
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}
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resolv_response_close_record (b);
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}
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static void
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check_forward_1 (const char *name, int family)
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{
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unsigned char lsb;
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if (strncmp (name, "2.", 2) == 0)
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lsb = 2;
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else
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lsb = 1;
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char expected_hostent_v4[200];
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snprintf (expected_hostent_v4, sizeof (expected_hostent_v4),
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"name: %s\naddress: 192.0.2.%d\n", name, lsb);
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char expected_hostent_v6[200];
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snprintf (expected_hostent_v6, sizeof (expected_hostent_v6),
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"name: %s\naddress: 2001:db8::%d\n", name, lsb);
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char expected_ai[200];
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unsigned char address[16];
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size_t address_length;
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char *expected_hostent;
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switch (family)
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{
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case AF_INET:
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expected_hostent = expected_hostent_v4;
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snprintf (expected_ai, sizeof (expected_ai),
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"address: STREAM/TCP 192.0.2.%d 80\n", lsb);
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TEST_VERIFY_EXIT (sizeof (address_ipv4) == sizeof (struct in_addr));
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memcpy (address, address_ipv4, sizeof (address_ipv4));
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address_length = sizeof (address_ipv4);
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break;
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case AF_INET6:
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expected_hostent = expected_hostent_v6;
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snprintf (expected_ai, sizeof (expected_ai),
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"address: STREAM/TCP 2001:db8::%d 80\n", lsb);
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TEST_VERIFY_EXIT (sizeof (address_ipv6) == sizeof (struct in6_addr));
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memcpy (address, address_ipv6, sizeof (address_ipv6));
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address_length = sizeof (address_ipv6);
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break;
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case AF_UNSPEC:
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expected_hostent = NULL;
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snprintf (expected_ai, sizeof (expected_ai),
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"address: STREAM/TCP 192.0.2.%d 80\n"
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"address: STREAM/TCP 2001:db8::%d 80\n",
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lsb, lsb);
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address_length = 0;
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break;
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default:
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FAIL_EXIT1 ("unknown address family %d", family);
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}
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if (family == AF_INET)
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{
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struct hostent *e = gethostbyname (name);
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check_hostent (name, e, expected_hostent_v4);
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}
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if (family != AF_UNSPEC)
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{
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struct hostent *e = gethostbyname2 (name, family);
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check_hostent (name, e, expected_hostent);
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}
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if (address_length > 0)
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{
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address[address_length - 1] = lsb;
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struct hostent *e = gethostbyaddr (address, address_length, family);
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check_hostent (name, e, expected_hostent);
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}
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struct addrinfo hints =
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{
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.ai_family = family,
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.ai_socktype = SOCK_STREAM,
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.ai_protocol = IPPROTO_TCP,
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};
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struct addrinfo *ai;
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int ret = getaddrinfo (name, "80", &hints, &ai);
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check_addrinfo (name, ai, ret, expected_ai);
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if (ret == 0)
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{
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for (struct addrinfo *p = ai; p != NULL; p = p->ai_next)
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{
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char host[200];
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ret = getnameinfo (p->ai_addr, p->ai_addrlen,
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host, sizeof (host),
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NULL, 0, /* service */
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0);
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if (ret != 0)
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{
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support_record_failure ();
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printf ("error: getnameinfo: %d\n", ret);
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}
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else
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{
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if (lsb == 1)
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TEST_VERIFY (strcmp (host, "host.example") == 0);
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else
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TEST_VERIFY (strcmp (host, "2.host.example") == 0);
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}
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}
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freeaddrinfo (ai);
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}
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}
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static void
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check_forward (int family)
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{
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check_forward_1 ("host.example", family);
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check_forward_1 ("2.host.example", family);
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}
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static int
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do_test (void)
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{
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for (int force_tcp = 0; force_tcp < 2; ++force_tcp)
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for (int nscount = 1; nscount <= 3; ++nscount)
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for (int disable_server = -1; disable_server < nscount; ++disable_server)
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for (drop_server = -1; drop_server < nscount; ++drop_server)
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{
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/* A disabled server will never receive queries and
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therefore cannot drop them. */
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if (drop_server >= 0 && drop_server == disable_server)
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continue;
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/* No servers remaining to query, all queries are expected
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to fail. */
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int broken_servers = (disable_server >= 0) + (drop_server >= 0);
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if (nscount <= broken_servers)
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continue;
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if (test_verbose > 0)
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printf ("info: tcp=%d nscount=%d disable=%d drop=%d\n",
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force_tcp, nscount, disable_server, drop_server);
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struct resolv_redirect_config config =
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{
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.response_callback = response,
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.nscount = nscount
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};
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if (disable_server >= 0)
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{
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config.servers[disable_server].disable_udp = true;
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config.servers[disable_server].disable_tcp = true;
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}
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struct resolv_test *aux = resolv_test_start (config);
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_res.options |= RES_ROTATE;
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/* Run a few queries to make sure that all of them
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succeed. We always perform more than nscount queries,
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so we cover all active servers due to RES_ROTATE. */
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for (size_t i = 0; i < resolv_max_test_servers; ++i)
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query_counts[i] = 0;
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check_forward (AF_INET);
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check_forward (AF_INET6);
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check_forward (AF_UNSPEC);
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for (int i = 0; i < nscount; ++i)
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{
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if (i != disable_server && i != drop_server
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&& query_counts[i] == 0)
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{
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support_record_failure ();
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printf ("error: nscount=%d, but no query to server %d\n",
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nscount, i);
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}
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}
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resolv_test_end (aux);
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}
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return 0;
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}
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#define TIMEOUT 300
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#include <support/test-driver.c>
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