netcat.c revision 1.1
1 /* $OpenBSD: netcat.c,v 1.172 2017/02/05 01:39:14 jca Exp $ */ 2 /* 3 * Copyright (c) 2001 Eric Jackson <ericj (at) monkey.org> 4 * Copyright (c) 2015 Bob Beck. All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. The name of the author may not be used to endorse or promote products 16 * derived from this software without specific prior written permission. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 19 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 20 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 21 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 22 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 23 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 24 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 25 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 26 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 27 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 28 */ 29 30 /* 31 * Re-written nc(1) for OpenBSD. Original implementation by 32 * *Hobbit* <hobbit (at) avian.org>. 33 */ 34 35 #include <sys/types.h> 36 #include <sys/socket.h> 37 #include <sys/uio.h> 38 #include <sys/un.h> 39 40 #include <netinet/in.h> 41 #include <netinet/tcp.h> 42 #include <netinet/ip.h> 43 #include <arpa/telnet.h> 44 45 #include <err.h> 46 #include <errno.h> 47 #include <limits.h> 48 #include <netdb.h> 49 #include <poll.h> 50 #include <signal.h> 51 #include <stdarg.h> 52 #include <stdio.h> 53 #include <stdlib.h> 54 #include <string.h> 55 #include <time.h> 56 #include <unistd.h> 57 #include <tls.h> 58 #include "atomicio.h" 59 60 #define PORT_MAX 65535 61 #define UNIX_DG_TMP_SOCKET_SIZE 19 62 63 #define POLL_STDIN 0 64 #define POLL_NETOUT 1 65 #define POLL_NETIN 2 66 #define POLL_STDOUT 3 67 #define BUFSIZE 16384 68 #define DEFAULT_CA_FILE "/etc/ssl/cert.pem" 69 70 #define TLS_ALL (1 << 1) 71 #define TLS_NOVERIFY (1 << 2) 72 #define TLS_NONAME (1 << 3) 73 #define TLS_CCERT (1 << 4) 74 #define TLS_MUSTSTAPLE (1 << 5) 75 76 /* Command Line Options */ 77 int dflag; /* detached, no stdin */ 78 int Fflag; /* fdpass sock to stdout */ 79 unsigned int iflag; /* Interval Flag */ 80 int kflag; /* More than one connect */ 81 int lflag; /* Bind to local port */ 82 int Nflag; /* shutdown() network socket */ 83 int nflag; /* Don't do name look up */ 84 char *Pflag; /* Proxy username */ 85 char *pflag; /* Localport flag */ 86 int rflag; /* Random ports flag */ 87 char *sflag; /* Source Address */ 88 int tflag; /* Telnet Emulation */ 89 int uflag; /* UDP - Default to TCP */ 90 int vflag; /* Verbosity */ 91 int xflag; /* Socks proxy */ 92 int zflag; /* Port Scan Flag */ 93 int Dflag; /* sodebug */ 94 int Iflag; /* TCP receive buffer size */ 95 int Oflag; /* TCP send buffer size */ 96 int Sflag; /* TCP MD5 signature option */ 97 int Tflag = -1; /* IP Type of Service */ 98 int rtableid = -1; 99 100 int usetls; /* use TLS */ 101 char *Cflag; /* Public cert file */ 102 char *Kflag; /* Private key file */ 103 char *oflag; /* OCSP stapling file */ 104 char *Rflag = DEFAULT_CA_FILE; /* Root CA file */ 105 int tls_cachanged; /* Using non-default CA file */ 106 int TLSopt; /* TLS options */ 107 char *tls_expectname; /* required name in peer cert */ 108 char *tls_expecthash; /* required hash of peer cert */ 109 110 int timeout = -1; 111 int family = AF_UNSPEC; 112 char *portlist[PORT_MAX+1]; 113 char *unix_dg_tmp_socket; 114 int ttl = -1; 115 int minttl = -1; 116 117 void atelnet(int, unsigned char *, unsigned int); 118 void build_ports(char *); 119 void help(void); 120 int local_listen(char *, char *, struct addrinfo); 121 void readwrite(int, struct tls *); 122 void fdpass(int nfd) __attribute__((noreturn)); 123 int remote_connect(const char *, const char *, struct addrinfo); 124 int timeout_connect(int, const struct sockaddr *, socklen_t); 125 int socks_connect(const char *, const char *, struct addrinfo, 126 const char *, const char *, struct addrinfo, int, const char *); 127 int udptest(int); 128 int unix_bind(char *, int); 129 int unix_connect(char *); 130 int unix_listen(char *); 131 void set_common_sockopts(int, int); 132 int map_tos(char *, int *); 133 int map_tls(char *, int *); 134 void report_connect(const struct sockaddr *, socklen_t, char *); 135 void report_tls(struct tls *tls_ctx, char * host, char *tls_expectname); 136 void usage(int); 137 ssize_t drainbuf(int, unsigned char *, size_t *, struct tls *); 138 ssize_t fillbuf(int, unsigned char *, size_t *, struct tls *); 139 void tls_setup_client(struct tls *, int, char *); 140 struct tls *tls_setup_server(struct tls *, int, char *); 141 142 int 143 main(int argc, char *argv[]) 144 { 145 int ch, s = -1, ret, socksv; 146 char *host, *uport; 147 struct addrinfo hints; 148 struct servent *sv; 149 socklen_t len; 150 struct sockaddr_storage cliaddr; 151 char *proxy, *proxyport = NULL; 152 const char *errstr; 153 struct addrinfo proxyhints; 154 char unix_dg_tmp_socket_buf[UNIX_DG_TMP_SOCKET_SIZE]; 155 struct tls_config *tls_cfg = NULL; 156 struct tls *tls_ctx = NULL; 157 158 ret = 1; 159 socksv = 5; 160 host = NULL; 161 uport = NULL; 162 sv = NULL; 163 164 signal(SIGPIPE, SIG_IGN); 165 166 while ((ch = getopt(argc, argv, 167 "46C:cDde:FH:hI:i:K:klM:m:NnO:o:P:p:R:rSs:T:tUuV:vw:X:x:z")) != -1) { 168 switch (ch) { 169 case '4': 170 family = AF_INET; 171 break; 172 case '6': 173 family = AF_INET6; 174 break; 175 case 'U': 176 family = AF_UNIX; 177 break; 178 case 'X': 179 if (strcasecmp(optarg, "connect") == 0) 180 socksv = -1; /* HTTP proxy CONNECT */ 181 else if (strcmp(optarg, "4") == 0) 182 socksv = 4; /* SOCKS v.4 */ 183 else if (strcmp(optarg, "5") == 0) 184 socksv = 5; /* SOCKS v.5 */ 185 else 186 errx(1, "unsupported proxy protocol"); 187 break; 188 case 'C': 189 Cflag = optarg; 190 break; 191 case 'c': 192 usetls = 1; 193 break; 194 case 'd': 195 dflag = 1; 196 break; 197 case 'e': 198 tls_expectname = optarg; 199 break; 200 case 'F': 201 Fflag = 1; 202 break; 203 case 'H': 204 tls_expecthash = optarg; 205 break; 206 case 'h': 207 help(); 208 break; 209 case 'i': 210 iflag = strtonum(optarg, 0, UINT_MAX, &errstr); 211 if (errstr) 212 errx(1, "interval %s: %s", errstr, optarg); 213 break; 214 case 'K': 215 Kflag = optarg; 216 break; 217 case 'k': 218 kflag = 1; 219 break; 220 case 'l': 221 lflag = 1; 222 break; 223 case 'M': 224 ttl = strtonum(optarg, 0, 255, &errstr); 225 if (errstr) 226 errx(1, "ttl is %s", errstr); 227 break; 228 case 'm': 229 minttl = strtonum(optarg, 0, 255, &errstr); 230 if (errstr) 231 errx(1, "minttl is %s", errstr); 232 break; 233 case 'N': 234 Nflag = 1; 235 break; 236 case 'n': 237 nflag = 1; 238 break; 239 case 'P': 240 Pflag = optarg; 241 break; 242 case 'p': 243 pflag = optarg; 244 break; 245 case 'R': 246 tls_cachanged = 1; 247 Rflag = optarg; 248 break; 249 case 'r': 250 rflag = 1; 251 break; 252 case 's': 253 sflag = optarg; 254 break; 255 case 't': 256 tflag = 1; 257 break; 258 case 'u': 259 uflag = 1; 260 break; 261 case 'V': 262 rtableid = (int)strtonum(optarg, 0, 263 RT_TABLEID_MAX, &errstr); 264 if (errstr) 265 errx(1, "rtable %s: %s", errstr, optarg); 266 break; 267 case 'v': 268 vflag = 1; 269 break; 270 case 'w': 271 timeout = strtonum(optarg, 0, INT_MAX / 1000, &errstr); 272 if (errstr) 273 errx(1, "timeout %s: %s", errstr, optarg); 274 timeout *= 1000; 275 break; 276 case 'x': 277 xflag = 1; 278 if ((proxy = strdup(optarg)) == NULL) 279 err(1, NULL); 280 break; 281 case 'z': 282 zflag = 1; 283 break; 284 case 'D': 285 Dflag = 1; 286 break; 287 case 'I': 288 Iflag = strtonum(optarg, 1, 65536 << 14, &errstr); 289 if (errstr != NULL) 290 errx(1, "TCP receive window %s: %s", 291 errstr, optarg); 292 break; 293 case 'O': 294 Oflag = strtonum(optarg, 1, 65536 << 14, &errstr); 295 if (errstr != NULL) 296 errx(1, "TCP send window %s: %s", 297 errstr, optarg); 298 break; 299 case 'o': 300 oflag = optarg; 301 break; 302 case 'S': 303 Sflag = 1; 304 break; 305 case 'T': 306 errstr = NULL; 307 errno = 0; 308 if (map_tos(optarg, &Tflag)) 309 break; 310 if (map_tls(optarg, &TLSopt)) 311 break; 312 if (strlen(optarg) > 1 && optarg[0] == '0' && 313 optarg[1] == 'x') 314 Tflag = (int)strtol(optarg, NULL, 16); 315 else 316 Tflag = (int)strtonum(optarg, 0, 255, 317 &errstr); 318 if (Tflag < 0 || Tflag > 255 || errstr || errno) 319 errx(1, "illegal tos/tls value %s", optarg); 320 break; 321 default: 322 usage(1); 323 } 324 } 325 argc -= optind; 326 argv += optind; 327 328 if (rtableid >= 0) 329 if (setrtable(rtableid) == -1) 330 err(1, "setrtable"); 331 332 if (family == AF_UNIX) { 333 if (pledge("stdio rpath wpath cpath tmppath unix", NULL) == -1) 334 err(1, "pledge"); 335 } else if (Fflag) { 336 if (Pflag) { 337 if (pledge("stdio inet dns sendfd tty", NULL) == -1) 338 err(1, "pledge"); 339 } else if (pledge("stdio inet dns sendfd", NULL) == -1) 340 err(1, "pledge"); 341 } else if (Pflag) { 342 if (pledge("stdio inet dns tty", NULL) == -1) 343 err(1, "pledge"); 344 } else if (usetls) { 345 if (pledge("stdio rpath inet dns", NULL) == -1) 346 err(1, "pledge"); 347 } else if (pledge("stdio inet dns", NULL) == -1) 348 err(1, "pledge"); 349 350 /* Cruft to make sure options are clean, and used properly. */ 351 if (argv[0] && !argv[1] && family == AF_UNIX) { 352 host = argv[0]; 353 uport = NULL; 354 } else if (argv[0] && !argv[1]) { 355 if (!lflag) 356 usage(1); 357 uport = argv[0]; 358 host = NULL; 359 } else if (argv[0] && argv[1]) { 360 host = argv[0]; 361 uport = argv[1]; 362 } else 363 usage(1); 364 365 if (lflag && sflag) 366 errx(1, "cannot use -s and -l"); 367 if (lflag && pflag) 368 errx(1, "cannot use -p and -l"); 369 if (lflag && zflag) 370 errx(1, "cannot use -z and -l"); 371 if (!lflag && kflag) 372 errx(1, "must use -l with -k"); 373 if (uflag && usetls) 374 errx(1, "cannot use -c and -u"); 375 if ((family == AF_UNIX) && usetls) 376 errx(1, "cannot use -c and -U"); 377 if ((family == AF_UNIX) && Fflag) 378 errx(1, "cannot use -F and -U"); 379 if (Fflag && usetls) 380 errx(1, "cannot use -c and -F"); 381 if (TLSopt && !usetls) 382 errx(1, "you must specify -c to use TLS options"); 383 if (Cflag && !usetls) 384 errx(1, "you must specify -c to use -C"); 385 if (Kflag && !usetls) 386 errx(1, "you must specify -c to use -K"); 387 if (oflag && !Cflag) 388 errx(1, "you must specify -C to use -o"); 389 if (tls_cachanged && !usetls) 390 errx(1, "you must specify -c to use -R"); 391 if (tls_expecthash && !usetls) 392 errx(1, "you must specify -c to use -H"); 393 if (tls_expectname && !usetls) 394 errx(1, "you must specify -c to use -e"); 395 396 /* Get name of temporary socket for unix datagram client */ 397 if ((family == AF_UNIX) && uflag && !lflag) { 398 if (sflag) { 399 unix_dg_tmp_socket = sflag; 400 } else { 401 strlcpy(unix_dg_tmp_socket_buf, "/tmp/nc.XXXXXXXXXX", 402 UNIX_DG_TMP_SOCKET_SIZE); 403 if (mktemp(unix_dg_tmp_socket_buf) == NULL) 404 err(1, "mktemp"); 405 unix_dg_tmp_socket = unix_dg_tmp_socket_buf; 406 } 407 } 408 409 /* Initialize addrinfo structure. */ 410 if (family != AF_UNIX) { 411 memset(&hints, 0, sizeof(struct addrinfo)); 412 hints.ai_family = family; 413 hints.ai_socktype = uflag ? SOCK_DGRAM : SOCK_STREAM; 414 hints.ai_protocol = uflag ? IPPROTO_UDP : IPPROTO_TCP; 415 if (nflag) 416 hints.ai_flags |= AI_NUMERICHOST; 417 } 418 419 if (xflag) { 420 if (uflag) 421 errx(1, "no proxy support for UDP mode"); 422 423 if (lflag) 424 errx(1, "no proxy support for listen"); 425 426 if (family == AF_UNIX) 427 errx(1, "no proxy support for unix sockets"); 428 429 if (sflag) 430 errx(1, "no proxy support for local source address"); 431 432 if (*proxy == '[') { 433 ++proxy; 434 proxyport = strchr(proxy, ']'); 435 if (proxyport == NULL) 436 errx(1, "missing closing bracket in proxy"); 437 *proxyport++ = '\0'; 438 if (*proxyport == '\0') 439 /* Use default proxy port. */ 440 proxyport = NULL; 441 else { 442 if (*proxyport == ':') 443 ++proxyport; 444 else 445 errx(1, "garbage proxy port delimiter"); 446 } 447 } else { 448 proxyport = strrchr(proxy, ':'); 449 if (proxyport != NULL) 450 *proxyport++ = '\0'; 451 } 452 453 memset(&proxyhints, 0, sizeof(struct addrinfo)); 454 proxyhints.ai_family = family; 455 proxyhints.ai_socktype = SOCK_STREAM; 456 proxyhints.ai_protocol = IPPROTO_TCP; 457 if (nflag) 458 proxyhints.ai_flags |= AI_NUMERICHOST; 459 } 460 461 if (usetls) { 462 if (Pflag) { 463 if (pledge("stdio inet dns tty rpath", NULL) == -1) 464 err(1, "pledge"); 465 } else if (pledge("stdio inet dns rpath", NULL) == -1) 466 err(1, "pledge"); 467 468 if (tls_init() == -1) 469 errx(1, "unable to initialize TLS"); 470 if ((tls_cfg = tls_config_new()) == NULL) 471 errx(1, "unable to allocate TLS config"); 472 if (Rflag && tls_config_set_ca_file(tls_cfg, Rflag) == -1) 473 errx(1, "%s", tls_config_error(tls_cfg)); 474 if (Cflag && tls_config_set_cert_file(tls_cfg, Cflag) == -1) 475 errx(1, "%s", tls_config_error(tls_cfg)); 476 if (Kflag && tls_config_set_key_file(tls_cfg, Kflag) == -1) 477 errx(1, "%s", tls_config_error(tls_cfg)); 478 if (oflag && tls_config_set_ocsp_staple_file(tls_cfg, oflag) == -1) 479 errx(1, "%s", tls_config_error(tls_cfg)); 480 if (TLSopt & TLS_ALL) { 481 if (tls_config_set_protocols(tls_cfg, 482 TLS_PROTOCOLS_ALL) != 0) 483 errx(1, "%s", tls_config_error(tls_cfg)); 484 if (tls_config_set_ciphers(tls_cfg, "all") != 0) 485 errx(1, "%s", tls_config_error(tls_cfg)); 486 } 487 if (!lflag && (TLSopt & TLS_CCERT)) 488 errx(1, "clientcert is only valid with -l"); 489 if (TLSopt & TLS_NONAME) 490 tls_config_insecure_noverifyname(tls_cfg); 491 if (TLSopt & TLS_NOVERIFY) { 492 if (tls_expecthash != NULL) 493 errx(1, "-H and -T noverify may not be used" 494 "together"); 495 tls_config_insecure_noverifycert(tls_cfg); 496 } 497 if (TLSopt & TLS_MUSTSTAPLE) 498 tls_config_ocsp_require_stapling(tls_cfg); 499 500 if (Pflag) { 501 if (pledge("stdio inet dns tty", NULL) == -1) 502 err(1, "pledge"); 503 } else if (pledge("stdio inet dns", NULL) == -1) 504 err(1, "pledge"); 505 } 506 if (lflag) { 507 struct tls *tls_cctx = NULL; 508 int connfd; 509 ret = 0; 510 511 if (family == AF_UNIX) { 512 if (uflag) 513 s = unix_bind(host, 0); 514 else 515 s = unix_listen(host); 516 } 517 518 if (usetls) { 519 tls_config_verify_client_optional(tls_cfg); 520 if ((tls_ctx = tls_server()) == NULL) 521 errx(1, "tls server creation failed"); 522 if (tls_configure(tls_ctx, tls_cfg) == -1) 523 errx(1, "tls configuration failed (%s)", 524 tls_error(tls_ctx)); 525 } 526 /* Allow only one connection at a time, but stay alive. */ 527 for (;;) { 528 if (family != AF_UNIX) 529 s = local_listen(host, uport, hints); 530 if (s < 0) 531 err(1, NULL); 532 /* 533 * For UDP and -k, don't connect the socket, let it 534 * receive datagrams from multiple socket pairs. 535 */ 536 if (uflag && kflag) 537 readwrite(s, NULL); 538 /* 539 * For UDP and not -k, we will use recvfrom() initially 540 * to wait for a caller, then use the regular functions 541 * to talk to the caller. 542 */ 543 else if (uflag && !kflag) { 544 int rv, plen; 545 char buf[16384]; 546 struct sockaddr_storage z; 547 548 len = sizeof(z); 549 plen = 2048; 550 rv = recvfrom(s, buf, plen, MSG_PEEK, 551 (struct sockaddr *)&z, &len); 552 if (rv < 0) 553 err(1, "recvfrom"); 554 555 rv = connect(s, (struct sockaddr *)&z, len); 556 if (rv < 0) 557 err(1, "connect"); 558 559 if (vflag) 560 report_connect((struct sockaddr *)&z, len, NULL); 561 562 readwrite(s, NULL); 563 } else { 564 len = sizeof(cliaddr); 565 connfd = accept4(s, (struct sockaddr *)&cliaddr, 566 &len, SOCK_NONBLOCK); 567 if (connfd == -1) { 568 /* For now, all errnos are fatal */ 569 err(1, "accept"); 570 } 571 if (vflag) 572 report_connect((struct sockaddr *)&cliaddr, len, 573 family == AF_UNIX ? host : NULL); 574 if ((usetls) && 575 (tls_cctx = tls_setup_server(tls_ctx, connfd, host))) 576 readwrite(connfd, tls_cctx); 577 if (!usetls) 578 readwrite(connfd, NULL); 579 if (tls_cctx) { 580 int i; 581 582 do { 583 i = tls_close(tls_cctx); 584 } while (i == TLS_WANT_POLLIN || 585 i == TLS_WANT_POLLOUT); 586 tls_free(tls_cctx); 587 tls_cctx = NULL; 588 } 589 close(connfd); 590 } 591 if (family != AF_UNIX) 592 close(s); 593 else if (uflag) { 594 if (connect(s, NULL, 0) < 0) 595 err(1, "connect"); 596 } 597 598 if (!kflag) 599 break; 600 } 601 } else if (family == AF_UNIX) { 602 ret = 0; 603 604 if ((s = unix_connect(host)) > 0 && !zflag) { 605 readwrite(s, NULL); 606 close(s); 607 } else 608 ret = 1; 609 610 if (uflag) 611 unlink(unix_dg_tmp_socket); 612 exit(ret); 613 614 } else { 615 int i = 0; 616 617 /* Construct the portlist[] array. */ 618 build_ports(uport); 619 620 /* Cycle through portlist, connecting to each port. */ 621 for (s = -1, i = 0; portlist[i] != NULL; i++) { 622 if (s != -1) 623 close(s); 624 625 if (usetls) { 626 if ((tls_ctx = tls_client()) == NULL) 627 errx(1, "tls client creation failed"); 628 if (tls_configure(tls_ctx, tls_cfg) == -1) 629 errx(1, "tls configuration failed (%s)", 630 tls_error(tls_ctx)); 631 } 632 if (xflag) 633 s = socks_connect(host, portlist[i], hints, 634 proxy, proxyport, proxyhints, socksv, 635 Pflag); 636 else 637 s = remote_connect(host, portlist[i], hints); 638 639 if (s == -1) 640 continue; 641 642 ret = 0; 643 if (vflag || zflag) { 644 /* For UDP, make sure we are connected. */ 645 if (uflag) { 646 if (udptest(s) == -1) { 647 ret = 1; 648 continue; 649 } 650 } 651 652 /* Don't look up port if -n. */ 653 if (nflag) 654 sv = NULL; 655 else { 656 sv = getservbyport( 657 ntohs(atoi(portlist[i])), 658 uflag ? "udp" : "tcp"); 659 } 660 661 fprintf(stderr, 662 "Connection to %s %s port [%s/%s] " 663 "succeeded!\n", host, portlist[i], 664 uflag ? "udp" : "tcp", 665 sv ? sv->s_name : "*"); 666 } 667 if (Fflag) 668 fdpass(s); 669 else { 670 if (usetls) 671 tls_setup_client(tls_ctx, s, host); 672 if (!zflag) 673 readwrite(s, tls_ctx); 674 if (tls_ctx) { 675 int j; 676 677 do { 678 j = tls_close(tls_ctx); 679 } while (j == TLS_WANT_POLLIN || 680 j == TLS_WANT_POLLOUT); 681 tls_free(tls_ctx); 682 tls_ctx = NULL; 683 } 684 } 685 } 686 } 687 688 if (s != -1) 689 close(s); 690 691 tls_config_free(tls_cfg); 692 693 exit(ret); 694 } 695 696 /* 697 * unix_bind() 698 * Returns a unix socket bound to the given path 699 */ 700 int 701 unix_bind(char *path, int flags) 702 { 703 struct sockaddr_un s_un; 704 int s, save_errno; 705 706 /* Create unix domain socket. */ 707 if ((s = socket(AF_UNIX, flags | (uflag ? SOCK_DGRAM : SOCK_STREAM), 708 0)) < 0) 709 return (-1); 710 711 memset(&s_un, 0, sizeof(struct sockaddr_un)); 712 s_un.sun_family = AF_UNIX; 713 714 if (strlcpy(s_un.sun_path, path, sizeof(s_un.sun_path)) >= 715 sizeof(s_un.sun_path)) { 716 close(s); 717 errno = ENAMETOOLONG; 718 return (-1); 719 } 720 721 if (bind(s, (struct sockaddr *)&s_un, sizeof(s_un)) < 0) { 722 save_errno = errno; 723 close(s); 724 errno = save_errno; 725 return (-1); 726 } 727 return (s); 728 } 729 730 void 731 tls_setup_client(struct tls *tls_ctx, int s, char *host) 732 { 733 int i; 734 735 if (tls_connect_socket(tls_ctx, s, 736 tls_expectname ? tls_expectname : host) == -1) { 737 errx(1, "tls connection failed (%s)", 738 tls_error(tls_ctx)); 739 } 740 do { 741 if ((i = tls_handshake(tls_ctx)) == -1) 742 errx(1, "tls handshake failed (%s)", 743 tls_error(tls_ctx)); 744 } while (i == TLS_WANT_POLLIN || i == TLS_WANT_POLLOUT); 745 if (vflag) 746 report_tls(tls_ctx, host, tls_expectname); 747 if (tls_expecthash && tls_peer_cert_hash(tls_ctx) && 748 strcmp(tls_expecthash, tls_peer_cert_hash(tls_ctx)) != 0) 749 errx(1, "peer certificate is not %s", tls_expecthash); 750 } 751 752 struct tls * 753 tls_setup_server(struct tls *tls_ctx, int connfd, char *host) 754 { 755 struct tls *tls_cctx; 756 757 if (tls_accept_socket(tls_ctx, &tls_cctx, 758 connfd) == -1) { 759 warnx("tls accept failed (%s)", 760 tls_error(tls_ctx)); 761 tls_cctx = NULL; 762 } else { 763 int i; 764 765 do { 766 if ((i = tls_handshake(tls_cctx)) == -1) 767 warnx("tls handshake failed (%s)", 768 tls_error(tls_cctx)); 769 } while(i == TLS_WANT_POLLIN || i == TLS_WANT_POLLOUT); 770 } 771 if (tls_cctx) { 772 int gotcert = tls_peer_cert_provided(tls_cctx); 773 774 if (vflag && gotcert) 775 report_tls(tls_cctx, host, tls_expectname); 776 if ((TLSopt & TLS_CCERT) && !gotcert) 777 warnx("No client certificate provided"); 778 else if (gotcert && tls_peer_cert_hash(tls_ctx) && tls_expecthash && 779 strcmp(tls_expecthash, tls_peer_cert_hash(tls_ctx)) != 0) 780 warnx("peer certificate is not %s", tls_expecthash); 781 else if (gotcert && tls_expectname && 782 (!tls_peer_cert_contains_name(tls_cctx, tls_expectname))) 783 warnx("name (%s) not found in client cert", 784 tls_expectname); 785 else { 786 return tls_cctx; 787 } 788 } 789 return NULL; 790 } 791 792 /* 793 * unix_connect() 794 * Returns a socket connected to a local unix socket. Returns -1 on failure. 795 */ 796 int 797 unix_connect(char *path) 798 { 799 struct sockaddr_un s_un; 800 int s, save_errno; 801 802 if (uflag) { 803 if ((s = unix_bind(unix_dg_tmp_socket, SOCK_CLOEXEC)) < 0) 804 return (-1); 805 } else { 806 if ((s = socket(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC, 0)) < 0) 807 return (-1); 808 } 809 810 memset(&s_un, 0, sizeof(struct sockaddr_un)); 811 s_un.sun_family = AF_UNIX; 812 813 if (strlcpy(s_un.sun_path, path, sizeof(s_un.sun_path)) >= 814 sizeof(s_un.sun_path)) { 815 close(s); 816 errno = ENAMETOOLONG; 817 return (-1); 818 } 819 if (connect(s, (struct sockaddr *)&s_un, sizeof(s_un)) < 0) { 820 save_errno = errno; 821 close(s); 822 errno = save_errno; 823 return (-1); 824 } 825 return (s); 826 827 } 828 829 /* 830 * unix_listen() 831 * Create a unix domain socket, and listen on it. 832 */ 833 int 834 unix_listen(char *path) 835 { 836 int s; 837 if ((s = unix_bind(path, 0)) < 0) 838 return (-1); 839 840 if (listen(s, 5) < 0) { 841 close(s); 842 return (-1); 843 } 844 return (s); 845 } 846 847 /* 848 * remote_connect() 849 * Returns a socket connected to a remote host. Properly binds to a local 850 * port or source address if needed. Returns -1 on failure. 851 */ 852 int 853 remote_connect(const char *host, const char *port, struct addrinfo hints) 854 { 855 struct addrinfo *res, *res0; 856 int s = -1, error, on = 1, save_errno; 857 858 if ((error = getaddrinfo(host, port, &hints, &res0))) 859 errx(1, "getaddrinfo: %s", gai_strerror(error)); 860 861 for (res = res0; res; res = res->ai_next) { 862 if ((s = socket(res->ai_family, res->ai_socktype | 863 SOCK_NONBLOCK, res->ai_protocol)) < 0) 864 continue; 865 866 /* Bind to a local port or source address if specified. */ 867 if (sflag || pflag) { 868 struct addrinfo ahints, *ares; 869 870 /* try SO_BINDANY, but don't insist */ 871 setsockopt(s, SOL_SOCKET, SO_BINDANY, &on, sizeof(on)); 872 memset(&ahints, 0, sizeof(struct addrinfo)); 873 ahints.ai_family = res->ai_family; 874 ahints.ai_socktype = uflag ? SOCK_DGRAM : SOCK_STREAM; 875 ahints.ai_protocol = uflag ? IPPROTO_UDP : IPPROTO_TCP; 876 ahints.ai_flags = AI_PASSIVE; 877 if ((error = getaddrinfo(sflag, pflag, &ahints, &ares))) 878 errx(1, "getaddrinfo: %s", gai_strerror(error)); 879 880 if (bind(s, (struct sockaddr *)ares->ai_addr, 881 ares->ai_addrlen) < 0) 882 err(1, "bind failed"); 883 freeaddrinfo(ares); 884 } 885 886 set_common_sockopts(s, res->ai_family); 887 888 if (timeout_connect(s, res->ai_addr, res->ai_addrlen) == 0) 889 break; 890 if (vflag) 891 warn("connect to %s port %s (%s) failed", host, port, 892 uflag ? "udp" : "tcp"); 893 894 save_errno = errno; 895 close(s); 896 errno = save_errno; 897 s = -1; 898 } 899 900 freeaddrinfo(res0); 901 902 return (s); 903 } 904 905 int 906 timeout_connect(int s, const struct sockaddr *name, socklen_t namelen) 907 { 908 struct pollfd pfd; 909 socklen_t optlen; 910 int optval; 911 int ret; 912 913 if ((ret = connect(s, name, namelen)) != 0 && errno == EINPROGRESS) { 914 pfd.fd = s; 915 pfd.events = POLLOUT; 916 if ((ret = poll(&pfd, 1, timeout)) == 1) { 917 optlen = sizeof(optval); 918 if ((ret = getsockopt(s, SOL_SOCKET, SO_ERROR, 919 &optval, &optlen)) == 0) { 920 errno = optval; 921 ret = optval == 0 ? 0 : -1; 922 } 923 } else if (ret == 0) { 924 errno = ETIMEDOUT; 925 ret = -1; 926 } else 927 err(1, "poll failed"); 928 } 929 930 return (ret); 931 } 932 933 /* 934 * local_listen() 935 * Returns a socket listening on a local port, binds to specified source 936 * address. Returns -1 on failure. 937 */ 938 int 939 local_listen(char *host, char *port, struct addrinfo hints) 940 { 941 struct addrinfo *res, *res0; 942 int s = -1, ret, x = 1, save_errno; 943 int error; 944 945 /* Allow nodename to be null. */ 946 hints.ai_flags |= AI_PASSIVE; 947 948 /* 949 * In the case of binding to a wildcard address 950 * default to binding to an ipv4 address. 951 */ 952 if (host == NULL && hints.ai_family == AF_UNSPEC) 953 hints.ai_family = AF_INET; 954 955 if ((error = getaddrinfo(host, port, &hints, &res0))) 956 errx(1, "getaddrinfo: %s", gai_strerror(error)); 957 958 for (res = res0; res; res = res->ai_next) { 959 if ((s = socket(res->ai_family, res->ai_socktype, 960 res->ai_protocol)) < 0) 961 continue; 962 963 ret = setsockopt(s, SOL_SOCKET, SO_REUSEPORT, &x, sizeof(x)); 964 if (ret == -1) 965 err(1, NULL); 966 967 set_common_sockopts(s, res->ai_family); 968 969 if (bind(s, (struct sockaddr *)res->ai_addr, 970 res->ai_addrlen) == 0) 971 break; 972 973 save_errno = errno; 974 close(s); 975 errno = save_errno; 976 s = -1; 977 } 978 979 if (!uflag && s != -1) { 980 if (listen(s, 1) < 0) 981 err(1, "listen"); 982 } 983 984 freeaddrinfo(res0); 985 986 return (s); 987 } 988 989 /* 990 * readwrite() 991 * Loop that polls on the network file descriptor and stdin. 992 */ 993 void 994 readwrite(int net_fd, struct tls *tls_ctx) 995 { 996 struct pollfd pfd[4]; 997 int stdin_fd = STDIN_FILENO; 998 int stdout_fd = STDOUT_FILENO; 999 unsigned char netinbuf[BUFSIZE]; 1000 size_t netinbufpos = 0; 1001 unsigned char stdinbuf[BUFSIZE]; 1002 size_t stdinbufpos = 0; 1003 int n, num_fds; 1004 ssize_t ret; 1005 1006 /* don't read from stdin if requested */ 1007 if (dflag) 1008 stdin_fd = -1; 1009 1010 /* stdin */ 1011 pfd[POLL_STDIN].fd = stdin_fd; 1012 pfd[POLL_STDIN].events = POLLIN; 1013 1014 /* network out */ 1015 pfd[POLL_NETOUT].fd = net_fd; 1016 pfd[POLL_NETOUT].events = 0; 1017 1018 /* network in */ 1019 pfd[POLL_NETIN].fd = net_fd; 1020 pfd[POLL_NETIN].events = POLLIN; 1021 1022 /* stdout */ 1023 pfd[POLL_STDOUT].fd = stdout_fd; 1024 pfd[POLL_STDOUT].events = 0; 1025 1026 while (1) { 1027 /* both inputs are gone, buffers are empty, we are done */ 1028 if (pfd[POLL_STDIN].fd == -1 && pfd[POLL_NETIN].fd == -1 && 1029 stdinbufpos == 0 && netinbufpos == 0) { 1030 close(net_fd); 1031 return; 1032 } 1033 /* both outputs are gone, we can't continue */ 1034 if (pfd[POLL_NETOUT].fd == -1 && pfd[POLL_STDOUT].fd == -1) { 1035 close(net_fd); 1036 return; 1037 } 1038 /* listen and net in gone, queues empty, done */ 1039 if (lflag && pfd[POLL_NETIN].fd == -1 && 1040 stdinbufpos == 0 && netinbufpos == 0) { 1041 close(net_fd); 1042 return; 1043 } 1044 1045 /* help says -i is for "wait between lines sent". We read and 1046 * write arbitrary amounts of data, and we don't want to start 1047 * scanning for newlines, so this is as good as it gets */ 1048 if (iflag) 1049 sleep(iflag); 1050 1051 /* poll */ 1052 num_fds = poll(pfd, 4, timeout); 1053 1054 /* treat poll errors */ 1055 if (num_fds == -1) { 1056 close(net_fd); 1057 err(1, "polling error"); 1058 } 1059 1060 /* timeout happened */ 1061 if (num_fds == 0) 1062 return; 1063 1064 /* treat socket error conditions */ 1065 for (n = 0; n < 4; n++) { 1066 if (pfd[n].revents & (POLLERR|POLLNVAL)) { 1067 pfd[n].fd = -1; 1068 } 1069 } 1070 /* reading is possible after HUP */ 1071 if (pfd[POLL_STDIN].events & POLLIN && 1072 pfd[POLL_STDIN].revents & POLLHUP && 1073 !(pfd[POLL_STDIN].revents & POLLIN)) 1074 pfd[POLL_STDIN].fd = -1; 1075 1076 if (pfd[POLL_NETIN].events & POLLIN && 1077 pfd[POLL_NETIN].revents & POLLHUP && 1078 !(pfd[POLL_NETIN].revents & POLLIN)) 1079 pfd[POLL_NETIN].fd = -1; 1080 1081 if (pfd[POLL_NETOUT].revents & POLLHUP) { 1082 if (Nflag) 1083 shutdown(pfd[POLL_NETOUT].fd, SHUT_WR); 1084 pfd[POLL_NETOUT].fd = -1; 1085 } 1086 /* if HUP, stop watching stdout */ 1087 if (pfd[POLL_STDOUT].revents & POLLHUP) 1088 pfd[POLL_STDOUT].fd = -1; 1089 /* if no net out, stop watching stdin */ 1090 if (pfd[POLL_NETOUT].fd == -1) 1091 pfd[POLL_STDIN].fd = -1; 1092 /* if no stdout, stop watching net in */ 1093 if (pfd[POLL_STDOUT].fd == -1) { 1094 if (pfd[POLL_NETIN].fd != -1) 1095 shutdown(pfd[POLL_NETIN].fd, SHUT_RD); 1096 pfd[POLL_NETIN].fd = -1; 1097 } 1098 1099 /* try to read from stdin */ 1100 if (pfd[POLL_STDIN].revents & POLLIN && stdinbufpos < BUFSIZE) { 1101 ret = fillbuf(pfd[POLL_STDIN].fd, stdinbuf, 1102 &stdinbufpos, NULL); 1103 if (ret == TLS_WANT_POLLIN) 1104 pfd[POLL_STDIN].events = POLLIN; 1105 else if (ret == TLS_WANT_POLLOUT) 1106 pfd[POLL_STDIN].events = POLLOUT; 1107 else if (ret == 0 || ret == -1) 1108 pfd[POLL_STDIN].fd = -1; 1109 /* read something - poll net out */ 1110 if (stdinbufpos > 0) 1111 pfd[POLL_NETOUT].events = POLLOUT; 1112 /* filled buffer - remove self from polling */ 1113 if (stdinbufpos == BUFSIZE) 1114 pfd[POLL_STDIN].events = 0; 1115 } 1116 /* try to write to network */ 1117 if (pfd[POLL_NETOUT].revents & POLLOUT && stdinbufpos > 0) { 1118 ret = drainbuf(pfd[POLL_NETOUT].fd, stdinbuf, 1119 &stdinbufpos, tls_ctx); 1120 if (ret == TLS_WANT_POLLIN) 1121 pfd[POLL_NETOUT].events = POLLIN; 1122 else if (ret == TLS_WANT_POLLOUT) 1123 pfd[POLL_NETOUT].events = POLLOUT; 1124 else if (ret == -1) 1125 pfd[POLL_NETOUT].fd = -1; 1126 /* buffer empty - remove self from polling */ 1127 if (stdinbufpos == 0) 1128 pfd[POLL_NETOUT].events = 0; 1129 /* buffer no longer full - poll stdin again */ 1130 if (stdinbufpos < BUFSIZE) 1131 pfd[POLL_STDIN].events = POLLIN; 1132 } 1133 /* try to read from network */ 1134 if (pfd[POLL_NETIN].revents & POLLIN && netinbufpos < BUFSIZE) { 1135 ret = fillbuf(pfd[POLL_NETIN].fd, netinbuf, 1136 &netinbufpos, tls_ctx); 1137 if (ret == TLS_WANT_POLLIN) 1138 pfd[POLL_NETIN].events = POLLIN; 1139 else if (ret == TLS_WANT_POLLOUT) 1140 pfd[POLL_NETIN].events = POLLOUT; 1141 else if (ret == -1) 1142 pfd[POLL_NETIN].fd = -1; 1143 /* eof on net in - remove from pfd */ 1144 if (ret == 0) { 1145 shutdown(pfd[POLL_NETIN].fd, SHUT_RD); 1146 pfd[POLL_NETIN].fd = -1; 1147 } 1148 /* read something - poll stdout */ 1149 if (netinbufpos > 0) 1150 pfd[POLL_STDOUT].events = POLLOUT; 1151 /* filled buffer - remove self from polling */ 1152 if (netinbufpos == BUFSIZE) 1153 pfd[POLL_NETIN].events = 0; 1154 /* handle telnet */ 1155 if (tflag) 1156 atelnet(pfd[POLL_NETIN].fd, netinbuf, 1157 netinbufpos); 1158 } 1159 /* try to write to stdout */ 1160 if (pfd[POLL_STDOUT].revents & POLLOUT && netinbufpos > 0) { 1161 ret = drainbuf(pfd[POLL_STDOUT].fd, netinbuf, 1162 &netinbufpos, NULL); 1163 if (ret == TLS_WANT_POLLIN) 1164 pfd[POLL_STDOUT].events = POLLIN; 1165 else if (ret == TLS_WANT_POLLOUT) 1166 pfd[POLL_STDOUT].events = POLLOUT; 1167 else if (ret == -1) 1168 pfd[POLL_STDOUT].fd = -1; 1169 /* buffer empty - remove self from polling */ 1170 if (netinbufpos == 0) 1171 pfd[POLL_STDOUT].events = 0; 1172 /* buffer no longer full - poll net in again */ 1173 if (netinbufpos < BUFSIZE) 1174 pfd[POLL_NETIN].events = POLLIN; 1175 } 1176 1177 /* stdin gone and queue empty? */ 1178 if (pfd[POLL_STDIN].fd == -1 && stdinbufpos == 0) { 1179 if (pfd[POLL_NETOUT].fd != -1 && Nflag) 1180 shutdown(pfd[POLL_NETOUT].fd, SHUT_WR); 1181 pfd[POLL_NETOUT].fd = -1; 1182 } 1183 /* net in gone and queue empty? */ 1184 if (pfd[POLL_NETIN].fd == -1 && netinbufpos == 0) { 1185 pfd[POLL_STDOUT].fd = -1; 1186 } 1187 } 1188 } 1189 1190 ssize_t 1191 drainbuf(int fd, unsigned char *buf, size_t *bufpos, struct tls *tls) 1192 { 1193 ssize_t n; 1194 ssize_t adjust; 1195 1196 if (tls) 1197 n = tls_write(tls, buf, *bufpos); 1198 else { 1199 n = write(fd, buf, *bufpos); 1200 /* don't treat EAGAIN, EINTR as error */ 1201 if (n == -1 && (errno == EAGAIN || errno == EINTR)) 1202 n = TLS_WANT_POLLOUT; 1203 } 1204 if (n <= 0) 1205 return n; 1206 /* adjust buffer */ 1207 adjust = *bufpos - n; 1208 if (adjust > 0) 1209 memmove(buf, buf + n, adjust); 1210 *bufpos -= n; 1211 return n; 1212 } 1213 1214 ssize_t 1215 fillbuf(int fd, unsigned char *buf, size_t *bufpos, struct tls *tls) 1216 { 1217 size_t num = BUFSIZE - *bufpos; 1218 ssize_t n; 1219 1220 if (tls) 1221 n = tls_read(tls, buf + *bufpos, num); 1222 else { 1223 n = read(fd, buf + *bufpos, num); 1224 /* don't treat EAGAIN, EINTR as error */ 1225 if (n == -1 && (errno == EAGAIN || errno == EINTR)) 1226 n = TLS_WANT_POLLIN; 1227 } 1228 if (n <= 0) 1229 return n; 1230 *bufpos += n; 1231 return n; 1232 } 1233 1234 /* 1235 * fdpass() 1236 * Pass the connected file descriptor to stdout and exit. 1237 */ 1238 void 1239 fdpass(int nfd) 1240 { 1241 struct msghdr mh; 1242 union { 1243 struct cmsghdr hdr; 1244 char buf[CMSG_SPACE(sizeof(int))]; 1245 } cmsgbuf; 1246 struct cmsghdr *cmsg; 1247 struct iovec iov; 1248 char c = '\0'; 1249 ssize_t r; 1250 struct pollfd pfd; 1251 1252 /* Avoid obvious stupidity */ 1253 if (isatty(STDOUT_FILENO)) 1254 errx(1, "Cannot pass file descriptor to tty"); 1255 1256 bzero(&mh, sizeof(mh)); 1257 bzero(&cmsgbuf, sizeof(cmsgbuf)); 1258 bzero(&iov, sizeof(iov)); 1259 1260 mh.msg_control = (caddr_t)&cmsgbuf.buf; 1261 mh.msg_controllen = sizeof(cmsgbuf.buf); 1262 cmsg = CMSG_FIRSTHDR(&mh); 1263 cmsg->cmsg_len = CMSG_LEN(sizeof(int)); 1264 cmsg->cmsg_level = SOL_SOCKET; 1265 cmsg->cmsg_type = SCM_RIGHTS; 1266 *(int *)CMSG_DATA(cmsg) = nfd; 1267 1268 iov.iov_base = &c; 1269 iov.iov_len = 1; 1270 mh.msg_iov = &iov; 1271 mh.msg_iovlen = 1; 1272 1273 bzero(&pfd, sizeof(pfd)); 1274 pfd.fd = STDOUT_FILENO; 1275 pfd.events = POLLOUT; 1276 for (;;) { 1277 r = sendmsg(STDOUT_FILENO, &mh, 0); 1278 if (r == -1) { 1279 if (errno == EAGAIN || errno == EINTR) { 1280 if (poll(&pfd, 1, -1) == -1) 1281 err(1, "poll"); 1282 continue; 1283 } 1284 err(1, "sendmsg"); 1285 } else if (r != 1) 1286 errx(1, "sendmsg: unexpected return value %zd", r); 1287 else 1288 break; 1289 } 1290 exit(0); 1291 } 1292 1293 /* Deal with RFC 854 WILL/WONT DO/DONT negotiation. */ 1294 void 1295 atelnet(int nfd, unsigned char *buf, unsigned int size) 1296 { 1297 unsigned char *p, *end; 1298 unsigned char obuf[4]; 1299 1300 if (size < 3) 1301 return; 1302 end = buf + size - 2; 1303 1304 for (p = buf; p < end; p++) { 1305 if (*p != IAC) 1306 continue; 1307 1308 obuf[0] = IAC; 1309 p++; 1310 if ((*p == WILL) || (*p == WONT)) 1311 obuf[1] = DONT; 1312 else if ((*p == DO) || (*p == DONT)) 1313 obuf[1] = WONT; 1314 else 1315 continue; 1316 1317 p++; 1318 obuf[2] = *p; 1319 if (atomicio(vwrite, nfd, obuf, 3) != 3) 1320 warn("Write Error!"); 1321 } 1322 } 1323 1324 1325 int 1326 strtoport(char *portstr, int udp) 1327 { 1328 struct servent *entry; 1329 const char *errstr; 1330 char *proto; 1331 int port = -1; 1332 1333 proto = udp ? "udp" : "tcp"; 1334 1335 port = strtonum(portstr, 1, PORT_MAX, &errstr); 1336 if (errstr == NULL) 1337 return port; 1338 if (errno != EINVAL) 1339 errx(1, "port number %s: %s", errstr, portstr); 1340 if ((entry = getservbyname(portstr, proto)) == NULL) 1341 errx(1, "service \"%s\" unknown", portstr); 1342 return ntohs(entry->s_port); 1343 } 1344 1345 /* 1346 * build_ports() 1347 * Build an array of ports in portlist[], listing each port 1348 * that we should try to connect to. 1349 */ 1350 void 1351 build_ports(char *p) 1352 { 1353 char *n; 1354 int hi, lo, cp; 1355 int x = 0; 1356 1357 if ((n = strchr(p, '-')) != NULL) { 1358 *n = '\0'; 1359 n++; 1360 1361 /* Make sure the ports are in order: lowest->highest. */ 1362 hi = strtoport(n, uflag); 1363 lo = strtoport(p, uflag); 1364 if (lo > hi) { 1365 cp = hi; 1366 hi = lo; 1367 lo = cp; 1368 } 1369 1370 /* 1371 * Initialize portlist with a random permutation. Based on 1372 * Knuth, as in ip_randomid() in sys/netinet/ip_id.c. 1373 */ 1374 if (rflag) { 1375 for (x = 0; x <= hi - lo; x++) { 1376 cp = arc4random_uniform(x + 1); 1377 portlist[x] = portlist[cp]; 1378 if (asprintf(&portlist[cp], "%d", x + lo) < 0) 1379 err(1, "asprintf"); 1380 } 1381 } else { /* Load ports sequentially. */ 1382 for (cp = lo; cp <= hi; cp++) { 1383 if (asprintf(&portlist[x], "%d", cp) < 0) 1384 err(1, "asprintf"); 1385 x++; 1386 } 1387 } 1388 } else { 1389 char *tmp; 1390 1391 hi = strtoport(p, uflag); 1392 if (asprintf(&tmp, "%d", hi) != -1) 1393 portlist[0] = tmp; 1394 else 1395 err(1, NULL); 1396 } 1397 } 1398 1399 /* 1400 * udptest() 1401 * Do a few writes to see if the UDP port is there. 1402 * Fails once PF state table is full. 1403 */ 1404 int 1405 udptest(int s) 1406 { 1407 int i, ret; 1408 1409 for (i = 0; i <= 3; i++) { 1410 if (write(s, "X", 1) == 1) 1411 ret = 1; 1412 else 1413 ret = -1; 1414 } 1415 return (ret); 1416 } 1417 1418 void 1419 set_common_sockopts(int s, int af) 1420 { 1421 int x = 1; 1422 1423 if (Sflag) { 1424 if (setsockopt(s, IPPROTO_TCP, TCP_MD5SIG, 1425 &x, sizeof(x)) == -1) 1426 err(1, NULL); 1427 } 1428 if (Dflag) { 1429 if (setsockopt(s, SOL_SOCKET, SO_DEBUG, 1430 &x, sizeof(x)) == -1) 1431 err(1, NULL); 1432 } 1433 if (Tflag != -1) { 1434 if (af == AF_INET && setsockopt(s, IPPROTO_IP, 1435 IP_TOS, &Tflag, sizeof(Tflag)) == -1) 1436 err(1, "set IP ToS"); 1437 1438 else if (af == AF_INET6 && setsockopt(s, IPPROTO_IPV6, 1439 IPV6_TCLASS, &Tflag, sizeof(Tflag)) == -1) 1440 err(1, "set IPv6 traffic class"); 1441 } 1442 if (Iflag) { 1443 if (setsockopt(s, SOL_SOCKET, SO_RCVBUF, 1444 &Iflag, sizeof(Iflag)) == -1) 1445 err(1, "set TCP receive buffer size"); 1446 } 1447 if (Oflag) { 1448 if (setsockopt(s, SOL_SOCKET, SO_SNDBUF, 1449 &Oflag, sizeof(Oflag)) == -1) 1450 err(1, "set TCP send buffer size"); 1451 } 1452 1453 if (ttl != -1) { 1454 if (af == AF_INET && setsockopt(s, IPPROTO_IP, 1455 IP_TTL, &ttl, sizeof(ttl))) 1456 err(1, "set IP TTL"); 1457 1458 else if (af == AF_INET6 && setsockopt(s, IPPROTO_IPV6, 1459 IPV6_UNICAST_HOPS, &ttl, sizeof(ttl))) 1460 err(1, "set IPv6 unicast hops"); 1461 } 1462 1463 if (minttl != -1) { 1464 if (af == AF_INET && setsockopt(s, IPPROTO_IP, 1465 IP_MINTTL, &minttl, sizeof(minttl))) 1466 err(1, "set IP min TTL"); 1467 1468 else if (af == AF_INET6 && setsockopt(s, IPPROTO_IPV6, 1469 IPV6_MINHOPCOUNT, &minttl, sizeof(minttl))) 1470 err(1, "set IPv6 min hop count"); 1471 } 1472 } 1473 1474 int 1475 map_tos(char *s, int *val) 1476 { 1477 /* DiffServ Codepoints and other TOS mappings */ 1478 const struct toskeywords { 1479 const char *keyword; 1480 int val; 1481 } *t, toskeywords[] = { 1482 { "af11", IPTOS_DSCP_AF11 }, 1483 { "af12", IPTOS_DSCP_AF12 }, 1484 { "af13", IPTOS_DSCP_AF13 }, 1485 { "af21", IPTOS_DSCP_AF21 }, 1486 { "af22", IPTOS_DSCP_AF22 }, 1487 { "af23", IPTOS_DSCP_AF23 }, 1488 { "af31", IPTOS_DSCP_AF31 }, 1489 { "af32", IPTOS_DSCP_AF32 }, 1490 { "af33", IPTOS_DSCP_AF33 }, 1491 { "af41", IPTOS_DSCP_AF41 }, 1492 { "af42", IPTOS_DSCP_AF42 }, 1493 { "af43", IPTOS_DSCP_AF43 }, 1494 { "critical", IPTOS_PREC_CRITIC_ECP }, 1495 { "cs0", IPTOS_DSCP_CS0 }, 1496 { "cs1", IPTOS_DSCP_CS1 }, 1497 { "cs2", IPTOS_DSCP_CS2 }, 1498 { "cs3", IPTOS_DSCP_CS3 }, 1499 { "cs4", IPTOS_DSCP_CS4 }, 1500 { "cs5", IPTOS_DSCP_CS5 }, 1501 { "cs6", IPTOS_DSCP_CS6 }, 1502 { "cs7", IPTOS_DSCP_CS7 }, 1503 { "ef", IPTOS_DSCP_EF }, 1504 { "inetcontrol", IPTOS_PREC_INTERNETCONTROL }, 1505 { "lowdelay", IPTOS_LOWDELAY }, 1506 { "netcontrol", IPTOS_PREC_NETCONTROL }, 1507 { "reliability", IPTOS_RELIABILITY }, 1508 { "throughput", IPTOS_THROUGHPUT }, 1509 { NULL, -1 }, 1510 }; 1511 1512 for (t = toskeywords; t->keyword != NULL; t++) { 1513 if (strcmp(s, t->keyword) == 0) { 1514 *val = t->val; 1515 return (1); 1516 } 1517 } 1518 1519 return (0); 1520 } 1521 1522 int 1523 map_tls(char *s, int *val) 1524 { 1525 const struct tlskeywords { 1526 const char *keyword; 1527 int val; 1528 } *t, tlskeywords[] = { 1529 { "tlsall", TLS_ALL }, 1530 { "noverify", TLS_NOVERIFY }, 1531 { "noname", TLS_NONAME }, 1532 { "clientcert", TLS_CCERT}, 1533 { "muststaple", TLS_MUSTSTAPLE}, 1534 { NULL, -1 }, 1535 }; 1536 1537 for (t = tlskeywords; t->keyword != NULL; t++) { 1538 if (strcmp(s, t->keyword) == 0) { 1539 *val |= t->val; 1540 return (1); 1541 } 1542 } 1543 return (0); 1544 } 1545 1546 void 1547 report_tls(struct tls * tls_ctx, char * host, char *tls_expectname) 1548 { 1549 time_t t; 1550 const char *ocsp_url; 1551 1552 fprintf(stderr, "TLS handshake negotiated %s/%s with host %s\n", 1553 tls_conn_version(tls_ctx), tls_conn_cipher(tls_ctx), host); 1554 fprintf(stderr, "Peer name: %s\n", 1555 tls_expectname ? tls_expectname : host); 1556 if (tls_peer_cert_subject(tls_ctx)) 1557 fprintf(stderr, "Subject: %s\n", 1558 tls_peer_cert_subject(tls_ctx)); 1559 if (tls_peer_cert_issuer(tls_ctx)) 1560 fprintf(stderr, "Issuer: %s\n", 1561 tls_peer_cert_issuer(tls_ctx)); 1562 if ((t = tls_peer_cert_notbefore(tls_ctx)) != -1) 1563 fprintf(stderr, "Valid From: %s", ctime(&t)); 1564 if ((t = tls_peer_cert_notafter(tls_ctx)) != -1) 1565 fprintf(stderr, "Valid Until: %s", ctime(&t)); 1566 if (tls_peer_cert_hash(tls_ctx)) 1567 fprintf(stderr, "Cert Hash: %s\n", 1568 tls_peer_cert_hash(tls_ctx)); 1569 ocsp_url = tls_peer_ocsp_url(tls_ctx); 1570 if (ocsp_url != NULL) 1571 fprintf(stderr, "OCSP URL: %s\n", ocsp_url); 1572 switch (tls_peer_ocsp_response_status(tls_ctx)) { 1573 case TLS_OCSP_RESPONSE_SUCCESSFUL: 1574 fprintf(stderr, "OCSP Stapling: %s\n", 1575 tls_peer_ocsp_result(tls_ctx) == NULL ? "" : 1576 tls_peer_ocsp_result(tls_ctx)); 1577 fprintf(stderr, 1578 " response_status=%d cert_status=%d crl_reason=%d\n", 1579 tls_peer_ocsp_response_status(tls_ctx), 1580 tls_peer_ocsp_cert_status(tls_ctx), 1581 tls_peer_ocsp_crl_reason(tls_ctx)); 1582 t = tls_peer_ocsp_this_update(tls_ctx); 1583 fprintf(stderr, " this update: %s", 1584 t != -1 ? ctime(&t) : "\n"); 1585 t = tls_peer_ocsp_next_update(tls_ctx); 1586 fprintf(stderr, " next update: %s", 1587 t != -1 ? ctime(&t) : "\n"); 1588 t = tls_peer_ocsp_revocation_time(tls_ctx); 1589 fprintf(stderr, " revocation: %s", 1590 t != -1 ? ctime(&t) : "\n"); 1591 break; 1592 case -1: 1593 break; 1594 default: 1595 fprintf(stderr, "OCSP Stapling: failure - response_status %d (%s)\n", 1596 tls_peer_ocsp_response_status(tls_ctx), 1597 tls_peer_ocsp_result(tls_ctx) == NULL ? "" : 1598 tls_peer_ocsp_result(tls_ctx)); 1599 break; 1600 1601 } 1602 } 1603 1604 void 1605 report_connect(const struct sockaddr *sa, socklen_t salen, char *path) 1606 { 1607 char remote_host[NI_MAXHOST]; 1608 char remote_port[NI_MAXSERV]; 1609 int herr; 1610 int flags = NI_NUMERICSERV; 1611 1612 if (path != NULL) { 1613 fprintf(stderr, "Connection on %s received!\n", path); 1614 return; 1615 } 1616 1617 if (nflag) 1618 flags |= NI_NUMERICHOST; 1619 1620 if ((herr = getnameinfo(sa, salen, 1621 remote_host, sizeof(remote_host), 1622 remote_port, sizeof(remote_port), 1623 flags)) != 0) { 1624 if (herr == EAI_SYSTEM) 1625 err(1, "getnameinfo"); 1626 else 1627 errx(1, "getnameinfo: %s", gai_strerror(herr)); 1628 } 1629 1630 fprintf(stderr, 1631 "Connection from %s %s " 1632 "received!\n", remote_host, remote_port); 1633 } 1634 1635 void 1636 help(void) 1637 { 1638 usage(0); 1639 fprintf(stderr, "\tCommand Summary:\n\ 1640 \t-4 Use IPv4\n\ 1641 \t-6 Use IPv6\n\ 1642 \t-C certfile Public key file\n\ 1643 \t-c Use TLS\n\ 1644 \t-D Enable the debug socket option\n\ 1645 \t-d Detach from stdin\n\ 1646 \t-e name\t Required name in peer certificate\n\ 1647 \t-F Pass socket fd\n\ 1648 \t-H hash\t Hash string of peer certificate\n\ 1649 \t-h This help text\n\ 1650 \t-I length TCP receive buffer length\n\ 1651 \t-i interval Delay interval for lines sent, ports scanned\n\ 1652 \t-K keyfile Private key file\n\ 1653 \t-k Keep inbound sockets open for multiple connects\n\ 1654 \t-l Listen mode, for inbound connects\n\ 1655 \t-M ttl Outgoing TTL / Hop Limit\n\ 1656 \t-m minttl Minimum incoming TTL / Hop Limit\n\ 1657 \t-N Shutdown the network socket after EOF on stdin\n\ 1658 \t-n Suppress name/port resolutions\n\ 1659 \t-O length TCP send buffer length\n\ 1660 \t-o staplefile Staple file\n\ 1661 \t-P proxyuser\tUsername for proxy authentication\n\ 1662 \t-p port\t Specify local port for remote connects\n\ 1663 \t-R CAfile CA bundle\n\ 1664 \t-r Randomize remote ports\n\ 1665 \t-S Enable the TCP MD5 signature option\n\ 1666 \t-s source Local source address\n\ 1667 \t-T keyword TOS value or TLS options\n\ 1668 \t-t Answer TELNET negotiation\n\ 1669 \t-U Use UNIX domain socket\n\ 1670 \t-u UDP mode\n\ 1671 \t-V rtable Specify alternate routing table\n\ 1672 \t-v Verbose\n\ 1673 \t-w timeout Timeout for connects and final net reads\n\ 1674 \t-X proto Proxy protocol: \"4\", \"5\" (SOCKS) or \"connect\"\n\ 1675 \t-x addr[:port]\tSpecify proxy address and port\n\ 1676 \t-z Zero-I/O mode [used for scanning]\n\ 1677 Port numbers can be individual or ranges: lo-hi [inclusive]\n"); 1678 exit(1); 1679 } 1680 1681 void 1682 usage(int ret) 1683 { 1684 fprintf(stderr, 1685 "usage: nc [-46cDdFhklNnrStUuvz] [-C certfile] [-e name] " 1686 "[-H hash] [-I length]\n" 1687 "\t [-i interval] [-K keyfile] [-M ttl] [-m minttl] [-O length]\n" 1688 "\t [-o staplefile] [-P proxy_username] [-p source_port] " 1689 "[-R CAfile]\n" 1690 "\t [-s source] [-T keyword] [-V rtable] [-w timeout] " 1691 "[-X proxy_protocol]\n" 1692 "\t [-x proxy_address[:port]] [destination] [port]\n"); 1693 if (ret) 1694 exit(1); 1695 } 1696
Indexes created Wed Sep 24 05:09:52 GMT 2025