1 /* $NetBSD: t_tcp_connect_port.c,v 1.2 2022/11/17 08:36:54 ozaki-r Exp $ */
2
3 /*-
4 * SPDX-License-Identifier: BSD-2-Clause
5 *
6 * Copyright (c) 2020 Netflix, Inc.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions are
10 * met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in
15 * the documentation and/or other materials provided with the
16 * distribution.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 * SUCH DAMAGE.
29 */
30
31 #include <sys/cdefs.h>
32 #ifdef __NetBSD__
33 __RCSID("$NetBSD: t_tcp_connect_port.c,v 1.2 2022/11/17 08:36:54 ozaki-r Exp $");
34 #define USE_RUMPKERNEL 1
35 #else
36 __FBSDID("$FreeBSD$");
37 #endif
38
39 #include <sys/param.h>
40 #include <sys/socket.h>
41 #include <sys/stat.h>
42 #include <sys/sysctl.h>
43
44 #include <netinet/in.h>
45
46 #include <err.h>
47 #include <errno.h>
48 #include <fcntl.h>
49 #include <stdio.h>
50 #include <stdlib.h>
51 #include <unistd.h>
52
53 #include <atf-c.h>
54
55 #ifdef USE_RUMPKERNEL
56 #include <rump/rump.h>
57 #include <rump/rump_syscalls.h>
58
59 #define socket rump_sys_socket
60 #define bind rump_sys_bind
61 #define listen rump_sys_listen
62 #define accept rump_sys_accept
63 #define connect rump_sys_connect
64 #define write rump_sys_write
65 #define close rump_sys_close
66 #define setsockopt rump_sys_setsockopt
67 #define getsockname rump_sys_getsockname
68 #endif /* USE_RUMPKERNEL */
69
70 #define SYSCTLBAKFILE "tmp.net.inet.ip.portrange.randomized"
71
72 /*
73 * Check if port allocation is randomized. If so, update it. Save the old
74 * value of the sysctl so it can be updated later.
75 */
76 static void
disable_random_ports(void)77 disable_random_ports(void)
78 {
79 #ifdef USE_RUMPKERNEL
80 rump_init(); /* XXX */
81 #else
82 int error, fd, random_new, random_save;
83 size_t sysctlsz;
84
85 /*
86 * Pre-emptively unlink our restoration file, so we will do no
87 * restoration on error.
88 */
89 unlink(SYSCTLBAKFILE);
90
91 /*
92 * Disable the net.inet.ip.portrange.randomized sysctl. Save the
93 * old value so we can restore it, if necessary.
94 */
95 random_new = 0;
96 sysctlsz = sizeof(random_save);
97 error = sysctlbyname("net.inet.ip.portrange.randomized", &random_save,
98 &sysctlsz, &random_new, sizeof(random_new));
99 if (error) {
100 warn("sysctlbyname(\"net.inet.ip.portrange.randomized\") "
101 "failed");
102 atf_tc_skip("Unable to set sysctl");
103 }
104 if (sysctlsz != sizeof(random_save)) {
105 fprintf(stderr, "Error: unexpected sysctl value size "
106 "(expected %zu, actual %zu)\n", sizeof(random_save),
107 sysctlsz);
108 goto restore_sysctl;
109 }
110
111 /* Open the backup file, write the contents, and close it. */
112 fd = open(SYSCTLBAKFILE, O_WRONLY|O_CREAT|O_TRUNC|O_EXCL,
113 S_IRUSR|S_IWUSR);
114 if (fd < 0) {
115 warn("error opening sysctl backup file");
116 goto restore_sysctl;
117 }
118 error = write(fd, &random_save, sizeof(random_save));
119 if (error < 0) {
120 warn("error writing saved value to sysctl backup file");
121 goto cleanup_and_restore;
122 }
123 if (error != (int)sizeof(random_save)) {
124 fprintf(stderr,
125 "Error writing saved value to sysctl backup file: "
126 "(expected %zu, actual %d)\n", sizeof(random_save), error);
127 goto cleanup_and_restore;
128 }
129 error = close(fd);
130 if (error) {
131 warn("error closing sysctl backup file");
132 cleanup_and_restore:
133 (void)close(fd);
134 (void)unlink(SYSCTLBAKFILE);
135 restore_sysctl:
136 (void)sysctlbyname("net.inet.ip.portrange.randomized", NULL,
137 NULL, &random_save, sysctlsz);
138 atf_tc_skip("Error setting sysctl");
139 }
140 #endif /* USE_RUMPKERNEL */
141 }
142
143 /*
144 * Restore the sysctl value from the backup file and delete the backup file.
145 */
146 static void
restore_random_ports(void)147 restore_random_ports(void)
148 {
149 #ifndef USE_RUMPKERNEL
150 int error, fd, random_save;
151
152 /* Open the backup file, read the contents, close it, and delete it. */
153 fd = open(SYSCTLBAKFILE, O_RDONLY);
154 if (fd < 0) {
155 warn("error opening sysctl backup file");
156 return;
157 }
158 error = read(fd, &random_save, sizeof(random_save));
159 if (error < 0) {
160 warn("error reading saved value from sysctl backup file");
161 return;
162 }
163 if (error != (int)sizeof(random_save)) {
164 fprintf(stderr,
165 "Error reading saved value from sysctl backup file: "
166 "(expected %zu, actual %d)\n", sizeof(random_save), error);
167 return;
168 }
169 error = close(fd);
170 if (error)
171 warn("error closing sysctl backup file");
172 error = unlink(SYSCTLBAKFILE);
173 if (error)
174 warn("error removing sysctl backup file");
175
176 /* Restore the saved sysctl value. */
177 error = sysctlbyname("net.inet.ip.portrange.randomized", NULL, NULL,
178 &random_save, sizeof(random_save));
179 if (error)
180 warn("sysctlbyname(\"net.inet.ip.portrange.randomized\") "
181 "failed while restoring value");
182 #endif /* USE_RUMPKERNEL */
183 }
184
185 /*
186 * Given a domain and sockaddr, open a listening socket with automatic port
187 * selection. Then, try to connect 64K times. Ensure the connected socket never
188 * uses an overlapping port.
189 */
190 static void
connect_loop(int domain,const struct sockaddr * addr)191 connect_loop(int domain, const struct sockaddr *addr)
192 {
193 union {
194 struct sockaddr saddr;
195 struct sockaddr_in saddr4;
196 struct sockaddr_in6 saddr6;
197 } su_clnt, su_srvr;
198 socklen_t salen;
199 int asock, csock, error, i, lsock;
200 const struct linger lopt = { 1, 0 };
201
202 /*
203 * Disable the net.inet.ip.portrange.randomized sysctl. Assuming an
204 * otherwise idle system, this makes the kernel try all possible
205 * ports sequentially and makes it more likely it will try the
206 * port on which we have a listening socket.
207 */
208 disable_random_ports();
209
210 /* Setup the listen socket. */
211 lsock = socket(domain, SOCK_STREAM, 0);
212 ATF_REQUIRE_MSG(lsock >= 0, "socket() for listen socket failed: %s",
213 strerror(errno));
214 error = bind(lsock, addr, addr->sa_len);
215 ATF_REQUIRE_MSG(error == 0, "bind() failed: %s", strerror(errno));
216 error = listen(lsock, 1);
217 ATF_REQUIRE_MSG(error == 0, "listen() failed: %s", strerror(errno));
218
219 /*
220 * Get the address of the listen socket, which will be the destination
221 * address for our connection attempts.
222 */
223 salen = sizeof(su_srvr);
224 error = getsockname(lsock, &su_srvr.saddr, &salen);
225 ATF_REQUIRE_MSG(error == 0,
226 "getsockname() for listen socket failed: %s",
227 strerror(errno));
228 ATF_REQUIRE_MSG(salen == (domain == PF_INET ?
229 sizeof(struct sockaddr_in) : sizeof(struct sockaddr_in6)),
230 "unexpected sockaddr size");
231 ATF_REQUIRE_MSG(su_srvr.saddr.sa_len == (domain == PF_INET ?
232 sizeof(struct sockaddr_in) : sizeof(struct sockaddr_in6)),
233 "unexpected sa_len size");
234
235 /* Open 64K connections in a loop. */
236 for (i = 0; i < 65536; i++) {
237 csock = socket(domain, SOCK_STREAM, 0);
238 ATF_REQUIRE_MSG(csock >= 0,
239 "socket() for client socket %d failed: %s",
240 i, strerror(errno));
241
242 error = connect(csock, &su_srvr.saddr, su_srvr.saddr.sa_len);
243 ATF_REQUIRE_MSG(error == 0,
244 "connect() for client socket %d failed: %s",
245 i, strerror(errno));
246
247 error = setsockopt(csock, SOL_SOCKET, SO_LINGER, &lopt,
248 sizeof(lopt));
249 ATF_REQUIRE_MSG(error == 0,
250 "Setting linger for client socket %d failed: %s",
251 i, strerror(errno));
252
253 /* Ascertain the client socket address. */
254 salen = sizeof(su_clnt);
255 error = getsockname(csock, &su_clnt.saddr, &salen);
256 ATF_REQUIRE_MSG(error == 0,
257 "getsockname() for client socket %d failed: %s",
258 i, strerror(errno));
259 ATF_REQUIRE_MSG(salen == (domain == PF_INET ?
260 sizeof(struct sockaddr_in) : sizeof(struct sockaddr_in6)),
261 "unexpected sockaddr size for client socket %d", i);
262
263 /* Ensure the ports do not match. */
264 switch (domain) {
265 case PF_INET:
266 ATF_REQUIRE_MSG(su_clnt.saddr4.sin_port !=
267 su_srvr.saddr4.sin_port,
268 "client socket %d using the same port as server",
269 i);
270 break;
271 case PF_INET6:
272 ATF_REQUIRE_MSG(su_clnt.saddr6.sin6_port !=
273 su_srvr.saddr6.sin6_port,
274 "client socket %d using the same port as server",
275 i);
276 break;
277 }
278
279 /* Accept the socket and close both ends. */
280 asock = accept(lsock, NULL, NULL);
281 ATF_REQUIRE_MSG(asock >= 0,
282 "accept() failed for client socket %d: %s",
283 i, strerror(errno));
284
285 error = close(asock);
286 ATF_REQUIRE_MSG(error == 0,
287 "close() failed for accepted socket %d: %s",
288 i, strerror(errno));
289
290 error = close(csock);
291 ATF_REQUIRE_MSG(error == 0,
292 "close() failed for client socket %d: %s",
293 i, strerror(errno));
294 }
295 }
296
297 ATF_TC_WITH_CLEANUP(basic_ipv4);
ATF_TC_HEAD(basic_ipv4,tc)298 ATF_TC_HEAD(basic_ipv4, tc)
299 {
300
301 atf_tc_set_md_var(tc, "require.user", "root");
302 #ifndef USE_RUMPKERNEL
303 atf_tc_set_md_var(tc, "require.config", "allow_sysctl_side_effects");
304 #endif
305 atf_tc_set_md_var(tc, "descr",
306 "Check automatic local port assignment during TCP connect calls");
307 }
308
ATF_TC_BODY(basic_ipv4,tc)309 ATF_TC_BODY(basic_ipv4, tc)
310 {
311 struct sockaddr_in saddr4;
312
313 memset(&saddr4, 0, sizeof(saddr4));
314 saddr4.sin_len = sizeof(saddr4);
315 saddr4.sin_family = AF_INET;
316 saddr4.sin_port = htons(0);
317 saddr4.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
318
319 connect_loop(PF_INET, (const struct sockaddr *)&saddr4);
320 }
321
ATF_TC_CLEANUP(basic_ipv4,tc)322 ATF_TC_CLEANUP(basic_ipv4, tc)
323 {
324
325 restore_random_ports();
326 }
327
328 ATF_TC_WITH_CLEANUP(basic_ipv6);
ATF_TC_HEAD(basic_ipv6,tc)329 ATF_TC_HEAD(basic_ipv6, tc)
330 {
331
332 atf_tc_set_md_var(tc, "require.user", "root");
333 #ifndef USE_RUMPKERNEL
334 atf_tc_set_md_var(tc, "require.config", "allow_sysctl_side_effects");
335 #endif
336 atf_tc_set_md_var(tc, "descr",
337 "Check automatic local port assignment during TCP connect calls");
338 }
339
ATF_TC_BODY(basic_ipv6,tc)340 ATF_TC_BODY(basic_ipv6, tc)
341 {
342 struct sockaddr_in6 saddr6;
343
344 memset(&saddr6, 0, sizeof(saddr6));
345 saddr6.sin6_len = sizeof(saddr6);
346 saddr6.sin6_family = AF_INET6;
347 saddr6.sin6_port = htons(0);
348 saddr6.sin6_addr = in6addr_loopback;
349
350 connect_loop(PF_INET6, (const struct sockaddr *)&saddr6);
351 }
352
ATF_TC_CLEANUP(basic_ipv6,tc)353 ATF_TC_CLEANUP(basic_ipv6, tc)
354 {
355
356 restore_random_ports();
357 }
358
ATF_TP_ADD_TCS(tp)359 ATF_TP_ADD_TCS(tp)
360 {
361 ATF_TP_ADD_TC(tp, basic_ipv4);
362 ATF_TP_ADD_TC(tp, basic_ipv6);
363
364 return (atf_no_error());
365 }
366
367