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 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 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 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); 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 } 308 309 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 } 321 322 ATF_TC_CLEANUP(basic_ipv4, tc) 323 { 324 325 restore_random_ports(); 326 } 327 328 ATF_TC_WITH_CLEANUP(basic_ipv6); 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 } 339 340 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 } 352 353 ATF_TC_CLEANUP(basic_ipv6, tc) 354 { 355 356 restore_random_ports(); 357 } 358 359 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
Indexes created Sat Sep 20 22:09:52 GMT 2025