1 /* Test search/default domain name behavior.
2 Copyright (C) 2016-2023 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 <stdlib.h>
21 #include <string.h>
22 #include <support/check.h>
23 #include <support/check_nss.h>
24 #include <support/resolv_test.h>
25 #include <support/support.h>
26 #include <support/xmemstream.h>
27
28 struct item
29 {
30 const char *name;
31 int response;
32 };
33
34 const struct item items[] =
35 {
36 {"hostname.usersys.example.com", 1},
37 {"hostname.corp.example.com", 1},
38 {"hostname.example.com", 1},
39
40 {"mail.corp.example.com", 1},
41 {"mail.example.com", 1},
42
43 {"file.corp.example.com", 2},
44 {"file.corp", 1},
45 {"file.example.com", 1},
46 {"servfail-usersys.usersys.example.com", -ns_r_servfail},
47 {"servfail-usersys.corp.example.com", 1},
48 {"servfail-usersys.example.com", 1},
49 {"servfail-corp.usersys.example.com", 1},
50 {"servfail-corp.corp.example.com", -ns_r_servfail},
51 {"servfail-corp.example.com", 1},
52 {"www.example.com", 1},
53 {"large.example.com", 200},
54
55 /* Test query amplification with a SERVFAIL response combined with
56 a large RRset. */
57 {"large-servfail.usersys.example.com", -ns_r_servfail},
58 {"large-servfail.example.com", 2000},
59 {}
60 };
61
62 enum
63 {
64 name_not_found = -1,
65 name_no_data = -2
66 };
67
68 static int
69 find_name (const char *name)
70 {
71 for (int i = 0; items[i].name != NULL; ++i)
72 {
73 if (strcmp (name, items[i].name) == 0)
74 return i;
75 }
76 if (strcmp (name, "example.com") == 0
77 || strcmp (name, "usersys.example.com") == 0
78 || strcmp (name, "corp.example.com") == 0)
79 return name_no_data;
80 return name_not_found;
81 }
82
83 static int rcode_override_server_index = -1;
84 static int rcode_override;
85
86 static void
87 response (const struct resolv_response_context *ctx,
88 struct resolv_response_builder *b,
89 const char *qname, uint16_t qclass, uint16_t qtype)
90 {
91 if (ctx->server_index == rcode_override_server_index)
92 {
93 struct resolv_response_flags flags = {.rcode = rcode_override};
94 resolv_response_init (b, flags);
95 resolv_response_add_question (b, qname, qclass, qtype);
96 return;
97 }
98
99 int index = find_name (qname);
100 struct resolv_response_flags flags = {};
101 if (index == name_not_found)
102 flags.rcode = ns_r_nxdomain;
103 else if (index >= 0 && items[index].response < 0)
104 flags.rcode = -items[index].response;
105 else if (index >= 0 && items[index].response > 5 && !ctx->tcp)
106 /* Force TCP if more than 5 addresses where requested. */
107 flags.tc = true;
108 resolv_response_init (b, flags);
109 resolv_response_add_question (b, qname, qclass, qtype);
110
111 if (flags.tc || index < 0 || items[index].response < 0)
112 return;
113
114 resolv_response_section (b, ns_s_an);
115
116 for (int i = 0; i < items[index].response; ++i)
117 {
118 resolv_response_open_record (b, qname, qclass, qtype, 0);
119
120 switch (qtype)
121 {
122 case T_A:
123 {
124 char addr[4] = {10, index, i >> 8, i};
125 resolv_response_add_data (b, addr, sizeof (addr));
126 }
127 break;
128 case T_AAAA:
129 {
130 char addr[16]
131 = {0x20, 0x01, 0xd, 0xb8, 0, 0, 0, 0, 0, 0, 0, 0,
132 0, index + 1, (i + 1) >> 8, i + 1};
133 resolv_response_add_data (b, addr, sizeof (addr));
134 }
135 break;
136 default:
137 support_record_failure ();
138 printf ("error: unexpected QTYPE: %s/%u/%u\n",
139 qname, qclass, qtype);
140 }
141 resolv_response_close_record (b);
142 }
143 }
144
145 enum output_format
146 {
147 format_get, format_gai
148 };
149
150 static void
151 format_expected_1 (FILE *out, int family, enum output_format format, int index)
152 {
153 for (int i = 0; i < items[index].response; ++i)
154 {
155 char address[200];
156 switch (family)
157 {
158 case AF_INET:
159 snprintf (address, sizeof (address), "10.%d.%d.%d",
160 index, (i >> 8) & 0xff, i & 0xff);
161 break;
162 case AF_INET6:
163 snprintf (address, sizeof (address), "2001:db8::%x:%x",
164 index + 1, i + 1);
165 break;
166 default:
167 FAIL_EXIT1 ("unreachable");
168 }
169
170 switch (format)
171 {
172 case format_get:
173 fprintf (out, "address: %s\n", address);
174 break;
175 case format_gai:
176 fprintf (out, "address: STREAM/TCP %s 80\n", address);
177 }
178 }
179 }
180
181 static char *
182 format_expected (const char *fqdn, int family, enum output_format format)
183 {
184 int index = find_name (fqdn);
185 TEST_VERIFY_EXIT (index >= 0);
186 struct xmemstream stream;
187 xopen_memstream (&stream);
188
189 TEST_VERIFY_EXIT (items[index].response >= 0);
190 if (format == format_get)
191 fprintf (stream.out, "name: %s\n", items[index].name);
192 if (family == AF_INET || family == AF_UNSPEC)
193 format_expected_1 (stream.out, AF_INET, format, index);
194 if (family == AF_INET6 || family == AF_UNSPEC)
195 format_expected_1 (stream.out, AF_INET6, format, index);
196
197 xfclose_memstream (&stream);
198 return stream.buffer;
199 }
200
201 static void
202 do_get (const char *name, const char *fqdn, int family)
203 {
204 char *expected = format_expected (fqdn, family, format_get);
205 if (family == AF_INET)
206 {
207 char *query = xasprintf ("gethostbyname (\"%s\")", name);
208 check_hostent (query, gethostbyname (name), expected);
209 free (query);
210 }
211 char *query = xasprintf ("gethostbyname2 (\"%s\", %d)", name, family);
212 check_hostent (query, gethostbyname2 (name, family), expected);
213
214 /* Test res_search. */
215 int qtype;
216 switch (family)
217 {
218 case AF_INET:
219 qtype = T_A;
220 break;
221 case AF_INET6:
222 qtype = T_AAAA;
223 break;
224 default:
225 qtype = -1;
226 }
227 if (qtype >= 0)
228 {
229 int sz = 512;
230 unsigned char *response = xmalloc (sz);
231 int ret = res_search (name, C_IN, qtype, response, sz);
232 TEST_VERIFY_EXIT (ret >= 0);
233 if (ret > sz)
234 {
235 /* Truncation. Retry with a larger buffer. */
236 sz = 65535;
237 unsigned char *newptr = xrealloc (response, sz);
238 response = newptr;
239
240 ret = res_search (name, C_IN, qtype, response, sz);
241 TEST_VERIFY_EXIT (ret >= 0);
242 TEST_VERIFY_EXIT (ret < sz);
243 }
244 check_dns_packet (query, response, ret, expected);
245 free (response);
246 }
247
248 free (query);
249 free (expected);
250 }
251
252 static void
253 do_gai (const char *name, const char *fqdn, int family)
254 {
255 struct addrinfo hints =
256 {
257 .ai_family = family,
258 .ai_protocol = IPPROTO_TCP,
259 .ai_socktype = SOCK_STREAM
260 };
261 struct addrinfo *ai;
262 char *query = xasprintf ("%s:80 [%d]", name, family);
263 int ret = getaddrinfo (name, "80", &hints, &ai);
264 char *expected = format_expected (fqdn, family, format_gai);
265 check_addrinfo (query, ai, ret, expected);
266 if (ret == 0)
267 freeaddrinfo (ai);
268 free (expected);
269 free (query);
270 }
271
272 static void
273 do_both (const char *name, const char *fqdn)
274 {
275 do_get (name, fqdn, AF_INET);
276 do_get (name, fqdn, AF_INET6);
277 do_gai (name, fqdn, AF_INET);
278 do_gai (name, fqdn, AF_INET6);
279 do_gai (name, fqdn, AF_UNSPEC);
280 }
281
282 static void
283 do_test_all (bool unconnectable_server)
284 {
285 struct resolv_redirect_config config =
286 {
287 .response_callback = response,
288 .search = {"usersys.example.com", "corp.example.com", "example.com"},
289 };
290 struct resolv_test *obj = resolv_test_start (config);
291
292 if (unconnectable_server)
293 {
294 /* 255.255.255.255 results in an immediate connect failure. The
295 next server will supply the answer instead. This is a
296 triggering condition for bug 19791. */
297 _res.nsaddr_list[0].sin_addr.s_addr = -1;
298 _res.nsaddr_list[0].sin_port = htons (53);
299 }
300
301 do_both ("file", "file.corp.example.com");
302 do_both ("www", "www.example.com");
303 do_both ("servfail-usersys", "servfail-usersys.corp.example.com");
304 do_both ("servfail-corp", "servfail-corp.usersys.example.com");
305 do_both ("large", "large.example.com");
306 do_both ("large-servfail", "large-servfail.example.com");
307 do_both ("file.corp", "file.corp");
308
309 /* Check that SERVFAIL and REFUSED responses do not alter the search
310 path resolution. */
311 rcode_override_server_index = 0;
312 rcode_override = ns_r_servfail;
313 do_both ("hostname", "hostname.usersys.example.com");
314 do_both ("large", "large.example.com");
315 do_both ("large-servfail", "large-servfail.example.com");
316 rcode_override = ns_r_refused;
317 do_both ("hostname", "hostname.usersys.example.com");
318 do_both ("large", "large.example.com");
319 do_both ("large-servfail", "large-servfail.example.com");
320 /* Likewise, but with an NXDOMAIN for the first search path
321 entry. */
322 rcode_override = ns_r_servfail;
323 do_both ("mail", "mail.corp.example.com");
324 rcode_override = ns_r_refused;
325 do_both ("mail", "mail.corp.example.com");
326 /* Likewise, but with ndots handling. */
327 rcode_override = ns_r_servfail;
328 do_both ("file.corp", "file.corp");
329 rcode_override = ns_r_refused;
330 do_both ("file.corp", "file.corp");
331
332 resolv_test_end (obj);
333 }
334
335 static int
336 do_test (void)
337 {
338 for (int unconnectable_server = 0; unconnectable_server < 2;
339 ++unconnectable_server)
340 do_test_all (unconnectable_server);
341 return 0;
342 }
343
344 #include <support/test-driver.c>