1 /* $OpenBSD: netcat.c,v 1.203 2019/02/26 17:32:47 jsing Exp $ */ 2 /* 3 * Copyright (c) 2001 Eric Jackson <ericj@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@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 <ctype.h> 46 #include <err.h> 47 #include <errno.h> 48 #include <limits.h> 49 #include <netdb.h> 50 #include <poll.h> 51 #include <signal.h> 52 #include <stdarg.h> 53 #include <stdio.h> 54 #include <stdlib.h> 55 #include <string.h> 56 #include <time.h> 57 #include <tls.h> 58 #include <unistd.h> 59 60 #include "atomicio.h" 61 62 #if !defined(OpenBSD) 63 #define pledge(request, paths) 0 64 #define unveil(path, permissions) 0 65 #endif 66 67 #define PORT_MAX 65535 68 #define UNIX_DG_TMP_SOCKET_SIZE 19 69 70 #define POLL_STDIN 0 71 #define POLL_NETOUT 1 72 #define POLL_NETIN 2 73 #define POLL_STDOUT 3 74 #define BUFSIZE 16384 75 76 #define TLS_NOVERIFY (1 << 1) 77 #define TLS_NONAME (1 << 2) 78 #define TLS_CCERT (1 << 3) 79 #define TLS_MUSTSTAPLE (1 << 4) 80 81 /* Command Line Options */ 82 int dflag; /* detached, no stdin */ 83 int Fflag; /* fdpass sock to stdout */ 84 unsigned int iflag; /* Interval Flag */ 85 int kflag; /* More than one connect */ 86 int lflag; /* Bind to local port */ 87 int Nflag; /* shutdown() network socket */ 88 int nflag; /* Don't do name look up */ 89 char *Pflag; /* Proxy username */ 90 char *pflag; /* Localport flag */ 91 int rflag; /* Random ports flag */ 92 char *sflag; /* Source Address */ 93 int tflag; /* Telnet Emulation */ 94 int uflag; /* UDP - Default to TCP */ 95 int vflag; /* Verbosity */ 96 int xflag; /* Socks proxy */ 97 int zflag; /* Port Scan Flag */ 98 int Dflag; /* sodebug */ 99 int Iflag; /* TCP receive buffer size */ 100 int Oflag; /* TCP send buffer size */ 101 #ifdef TCP_MD5SIG 102 int Sflag; /* TCP MD5 signature option */ 103 #endif 104 int Tflag = -1; /* IP Type of Service */ 105 #ifdef SO_RTABLE 106 int rtableid = -1; 107 #endif 108 109 int usetls; /* use TLS */ 110 const char *Cflag; /* Public cert file */ 111 const char *Kflag; /* Private key file */ 112 const char *oflag; /* OCSP stapling file */ 113 const char *Rflag; /* Root CA file */ 114 int tls_cachanged; /* Using non-default CA file */ 115 int TLSopt; /* TLS options */ 116 char *tls_expectname; /* required name in peer cert */ 117 char *tls_expecthash; /* required hash of peer cert */ 118 char *tls_ciphers; /* TLS ciphers */ 119 char *tls_protocols; /* TLS protocols */ 120 FILE *Zflag; /* file to save peer cert */ 121 122 int recvcount, recvlimit; 123 int timeout = -1; 124 int family = AF_UNSPEC; 125 char *portlist[PORT_MAX+1]; 126 char *unix_dg_tmp_socket; 127 int ttl = -1; 128 int minttl = -1; 129 130 void atelnet(int, unsigned char *, unsigned int); 131 int strtoport(char *portstr, int udp); 132 void build_ports(char *); 133 void help(void) __attribute__((noreturn)); 134 int local_listen(const char *, const char *, struct addrinfo); 135 void readwrite(int, struct tls *); 136 void fdpass(int nfd) __attribute__((noreturn)); 137 int remote_connect(const char *, const char *, struct addrinfo); 138 int timeout_tls(int, struct tls *, int (*)(struct tls *)); 139 int timeout_connect(int, const struct sockaddr *, socklen_t); 140 int socks_connect(const char *, const char *, struct addrinfo, 141 const char *, const char *, struct addrinfo, int, const char *); 142 int udptest(int); 143 int unix_bind(char *, int); 144 int unix_connect(char *); 145 int unix_listen(char *); 146 void set_common_sockopts(int, int); 147 int process_tos_opt(char *, int *); 148 int process_tls_opt(char *, int *); 149 void save_peer_cert(struct tls *_tls_ctx, FILE *_fp); 150 void report_sock(const char *, const struct sockaddr *, socklen_t, char *); 151 void report_tls(struct tls *tls_ctx, char * host); 152 void usage(int); 153 ssize_t drainbuf(int, unsigned char *, size_t *, struct tls *); 154 ssize_t fillbuf(int, unsigned char *, size_t *, struct tls *); 155 void tls_setup_client(struct tls *, int, char *); 156 struct tls *tls_setup_server(struct tls *, int, char *); 157 158 int 159 main(int argc, char *argv[]) 160 { 161 int ch, s = -1, ret, socksv; 162 char *host, *uport; 163 struct addrinfo hints; 164 struct servent *sv; 165 socklen_t len; 166 struct sockaddr_storage cliaddr; 167 char *proxy = NULL, *proxyport = NULL; 168 const char *errstr; 169 struct addrinfo proxyhints; 170 char unix_dg_tmp_socket_buf[UNIX_DG_TMP_SOCKET_SIZE]; 171 struct tls_config *tls_cfg = NULL; 172 struct tls *tls_ctx = NULL; 173 uint32_t protocols; 174 175 ret = 1; 176 socksv = 5; 177 host = NULL; 178 uport = NULL; 179 sv = NULL; 180 Rflag = tls_default_ca_cert_file(); 181 182 signal(SIGPIPE, SIG_IGN); 183 184 while ((ch = getopt(argc, argv, 185 "46C:cDde:FH:hI:i:K:klM:m:NnO:o:P:p:R:rSs:T:tUuV:vW:w:X:x:Z:z")) 186 != -1) { 187 switch (ch) { 188 case '4': 189 family = AF_INET; 190 break; 191 case '6': 192 family = AF_INET6; 193 break; 194 case 'U': 195 family = AF_UNIX; 196 break; 197 case 'X': 198 if (strcasecmp(optarg, "connect") == 0) 199 socksv = -1; /* HTTP proxy CONNECT */ 200 else if (strcmp(optarg, "4") == 0) 201 socksv = 4; /* SOCKS v.4 */ 202 else if (strcmp(optarg, "5") == 0) 203 socksv = 5; /* SOCKS v.5 */ 204 else 205 errx(1, "unsupported proxy protocol"); 206 break; 207 case 'C': 208 Cflag = optarg; 209 break; 210 case 'c': 211 usetls = 1; 212 break; 213 case 'd': 214 dflag = 1; 215 break; 216 case 'e': 217 tls_expectname = optarg; 218 break; 219 case 'F': 220 Fflag = 1; 221 break; 222 case 'H': 223 tls_expecthash = optarg; 224 break; 225 case 'h': 226 help(); 227 break; 228 case 'i': 229 iflag = strtonum(optarg, 0, UINT_MAX, &errstr); 230 if (errstr) 231 errx(1, "interval %s: %s", errstr, optarg); 232 break; 233 case 'K': 234 Kflag = optarg; 235 break; 236 case 'k': 237 kflag = 1; 238 break; 239 case 'l': 240 lflag = 1; 241 break; 242 case 'M': 243 ttl = strtonum(optarg, 0, 255, &errstr); 244 if (errstr) 245 errx(1, "ttl is %s", errstr); 246 break; 247 case 'm': 248 minttl = strtonum(optarg, 0, 255, &errstr); 249 if (errstr) 250 errx(1, "minttl is %s", errstr); 251 break; 252 case 'N': 253 Nflag = 1; 254 break; 255 case 'n': 256 nflag = 1; 257 break; 258 case 'P': 259 Pflag = optarg; 260 break; 261 case 'p': 262 pflag = optarg; 263 break; 264 case 'R': 265 tls_cachanged = 1; 266 Rflag = optarg; 267 break; 268 case 'r': 269 rflag = 1; 270 break; 271 case 's': 272 sflag = optarg; 273 break; 274 case 't': 275 tflag = 1; 276 break; 277 case 'u': 278 uflag = 1; 279 break; 280 #ifdef SO_RTABLE 281 case 'V': 282 rtableid = (int)strtonum(optarg, 0, 283 RT_TABLEID_MAX, &errstr); 284 if (errstr) 285 errx(1, "rtable %s: %s", errstr, optarg); 286 break; 287 #endif 288 case 'v': 289 vflag = 1; 290 break; 291 case 'W': 292 recvlimit = strtonum(optarg, 1, INT_MAX, &errstr); 293 if (errstr) 294 errx(1, "receive limit %s: %s", errstr, optarg); 295 break; 296 case 'w': 297 timeout = strtonum(optarg, 0, INT_MAX / 1000, &errstr); 298 if (errstr) 299 errx(1, "timeout %s: %s", errstr, optarg); 300 timeout *= 1000; 301 break; 302 case 'x': 303 xflag = 1; 304 if ((proxy = strdup(optarg)) == NULL) 305 err(1, NULL); 306 break; 307 case 'Z': 308 if (strcmp(optarg, "-") == 0) 309 Zflag = stderr; 310 else if ((Zflag = fopen(optarg, "w")) == NULL) 311 err(1, "can't open %s", optarg); 312 break; 313 case 'z': 314 zflag = 1; 315 break; 316 case 'D': 317 Dflag = 1; 318 break; 319 case 'I': 320 Iflag = strtonum(optarg, 1, 65536 << 14, &errstr); 321 if (errstr != NULL) 322 errx(1, "TCP receive window %s: %s", 323 errstr, optarg); 324 break; 325 case 'O': 326 Oflag = strtonum(optarg, 1, 65536 << 14, &errstr); 327 if (errstr != NULL) 328 errx(1, "TCP send window %s: %s", 329 errstr, optarg); 330 break; 331 case 'o': 332 oflag = optarg; 333 break; 334 #ifdef TCP_MD5SIG 335 case 'S': 336 Sflag = 1; 337 break; 338 #endif 339 case 'T': 340 errstr = NULL; 341 errno = 0; 342 if (process_tls_opt(optarg, &TLSopt)) 343 break; 344 if (process_tos_opt(optarg, &Tflag)) 345 break; 346 if (strlen(optarg) > 1 && optarg[0] == '0' && 347 optarg[1] == 'x') 348 Tflag = (int)strtol(optarg, NULL, 16); 349 else 350 Tflag = (int)strtonum(optarg, 0, 255, 351 &errstr); 352 if (Tflag < 0 || Tflag > 255 || errstr || errno) 353 errx(1, "illegal tos/tls value %s", optarg); 354 break; 355 default: 356 usage(1); 357 } 358 } 359 argc -= optind; 360 argv += optind; 361 362 #ifdef SO_RTABLE 363 if (rtableid >= 0) 364 if (setrtable(rtableid) == -1) 365 err(1, "setrtable"); 366 #endif 367 368 /* Cruft to make sure options are clean, and used properly. */ 369 if (argv[0] && !argv[1] && family == AF_UNIX) { 370 host = argv[0]; 371 uport = NULL; 372 } else if (argv[0] && !argv[1]) { 373 if (!lflag) 374 usage(1); 375 uport = argv[0]; 376 host = NULL; 377 } else if (argv[0] && argv[1]) { 378 host = argv[0]; 379 uport = argv[1]; 380 } else 381 usage(1); 382 383 if (usetls) { 384 if (Cflag && unveil(Cflag, "r") == -1) 385 err(1, "unveil"); 386 if (unveil(Rflag, "r") == -1) 387 err(1, "unveil"); 388 if (Kflag && unveil(Kflag, "r") == -1) 389 err(1, "unveil"); 390 if (oflag && unveil(oflag, "r") == -1) 391 err(1, "unveil"); 392 } else { 393 if (family == AF_UNIX) { 394 if (unveil(host, "rwc") == -1) 395 err(1, "unveil"); 396 if (uflag && !lflag) { 397 if (unveil(sflag ? sflag : "/tmp", "rwc") == -1) 398 err(1, "unveil"); 399 } 400 } else { 401 if (unveil("/", "") == -1) 402 err(1, "unveil"); 403 } 404 } 405 406 if (family == AF_UNIX) { 407 if (pledge("stdio rpath wpath cpath tmppath unix", NULL) == -1) 408 err(1, "pledge"); 409 } else if (Fflag && Pflag) { 410 if (pledge("stdio inet dns sendfd tty", NULL) == -1) 411 err(1, "pledge"); 412 } else if (Fflag) { 413 if (pledge("stdio inet dns sendfd", NULL) == -1) 414 err(1, "pledge"); 415 } else if (Pflag && usetls) { 416 if (pledge("stdio rpath inet dns tty", NULL) == -1) 417 err(1, "pledge"); 418 } else if (Pflag) { 419 if (pledge("stdio inet dns tty", NULL) == -1) 420 err(1, "pledge"); 421 } else if (usetls) { 422 if (pledge("stdio rpath inet dns", NULL) == -1) 423 err(1, "pledge"); 424 } else if (pledge("stdio inet dns", NULL) == -1) 425 err(1, "pledge"); 426 427 if (lflag && sflag) 428 errx(1, "cannot use -s and -l"); 429 if (lflag && pflag) 430 errx(1, "cannot use -p and -l"); 431 if (lflag && zflag) 432 errx(1, "cannot use -z and -l"); 433 if (!lflag && kflag) 434 errx(1, "must use -l with -k"); 435 if (uflag && usetls) 436 errx(1, "cannot use -c and -u"); 437 if ((family == AF_UNIX) && usetls) 438 errx(1, "cannot use -c and -U"); 439 if ((family == AF_UNIX) && Fflag) 440 errx(1, "cannot use -F and -U"); 441 if (Fflag && usetls) 442 errx(1, "cannot use -c and -F"); 443 if (TLSopt && !usetls) 444 errx(1, "you must specify -c to use TLS options"); 445 if (Cflag && !usetls) 446 errx(1, "you must specify -c to use -C"); 447 if (Kflag && !usetls) 448 errx(1, "you must specify -c to use -K"); 449 if (Zflag && !usetls) 450 errx(1, "you must specify -c to use -Z"); 451 if (oflag && !Cflag) 452 errx(1, "you must specify -C to use -o"); 453 if (tls_cachanged && !usetls) 454 errx(1, "you must specify -c to use -R"); 455 if (tls_expecthash && !usetls) 456 errx(1, "you must specify -c to use -H"); 457 if (tls_expectname && !usetls) 458 errx(1, "you must specify -c to use -e"); 459 460 /* Get name of temporary socket for unix datagram client */ 461 if ((family == AF_UNIX) && uflag && !lflag) { 462 if (sflag) { 463 unix_dg_tmp_socket = sflag; 464 } else { 465 strlcpy(unix_dg_tmp_socket_buf, "/tmp/nc.XXXXXXXXXX", 466 UNIX_DG_TMP_SOCKET_SIZE); 467 if (mktemp(unix_dg_tmp_socket_buf) == NULL) 468 err(1, "mktemp"); 469 unix_dg_tmp_socket = unix_dg_tmp_socket_buf; 470 } 471 } 472 473 /* Initialize addrinfo structure. */ 474 if (family != AF_UNIX) { 475 memset(&hints, 0, sizeof(struct addrinfo)); 476 hints.ai_family = family; 477 hints.ai_socktype = uflag ? SOCK_DGRAM : SOCK_STREAM; 478 hints.ai_protocol = uflag ? IPPROTO_UDP : IPPROTO_TCP; 479 if (nflag) 480 hints.ai_flags |= AI_NUMERICHOST; 481 } 482 483 if (xflag) { 484 if (uflag) 485 errx(1, "no proxy support for UDP mode"); 486 487 if (lflag) 488 errx(1, "no proxy support for listen"); 489 490 if (family == AF_UNIX) 491 errx(1, "no proxy support for unix sockets"); 492 493 if (sflag) 494 errx(1, "no proxy support for local source address"); 495 496 if (*proxy == '[') { 497 ++proxy; 498 proxyport = strchr(proxy, ']'); 499 if (proxyport == NULL) 500 errx(1, "missing closing bracket in proxy"); 501 *proxyport++ = '\0'; 502 if (*proxyport == '\0') 503 /* Use default proxy port. */ 504 proxyport = NULL; 505 else { 506 if (*proxyport == ':') 507 ++proxyport; 508 else 509 errx(1, "garbage proxy port delimiter"); 510 } 511 } else { 512 proxyport = strrchr(proxy, ':'); 513 if (proxyport != NULL) 514 *proxyport++ = '\0'; 515 } 516 517 memset(&proxyhints, 0, sizeof(struct addrinfo)); 518 proxyhints.ai_family = family; 519 proxyhints.ai_socktype = SOCK_STREAM; 520 proxyhints.ai_protocol = IPPROTO_TCP; 521 if (nflag) 522 proxyhints.ai_flags |= AI_NUMERICHOST; 523 } 524 525 if (usetls) { 526 if ((tls_cfg = tls_config_new()) == NULL) 527 errx(1, "unable to allocate TLS config"); 528 if (Rflag && tls_config_set_ca_file(tls_cfg, Rflag) == -1) 529 errx(1, "%s", tls_config_error(tls_cfg)); 530 if (Cflag && tls_config_set_cert_file(tls_cfg, Cflag) == -1) 531 errx(1, "%s", tls_config_error(tls_cfg)); 532 if (Kflag && tls_config_set_key_file(tls_cfg, Kflag) == -1) 533 errx(1, "%s", tls_config_error(tls_cfg)); 534 if (oflag && tls_config_set_ocsp_staple_file(tls_cfg, oflag) == -1) 535 errx(1, "%s", tls_config_error(tls_cfg)); 536 if (tls_config_parse_protocols(&protocols, tls_protocols) == -1) 537 errx(1, "invalid TLS protocols `%s'", tls_protocols); 538 if (tls_config_set_protocols(tls_cfg, protocols) == -1) 539 errx(1, "%s", tls_config_error(tls_cfg)); 540 if (tls_config_set_ciphers(tls_cfg, tls_ciphers) == -1) 541 errx(1, "%s", tls_config_error(tls_cfg)); 542 if (!lflag && (TLSopt & TLS_CCERT)) 543 errx(1, "clientcert is only valid with -l"); 544 if (TLSopt & TLS_NONAME) 545 tls_config_insecure_noverifyname(tls_cfg); 546 if (TLSopt & TLS_NOVERIFY) { 547 if (tls_expecthash != NULL) 548 errx(1, "-H and -T noverify may not be used " 549 "together"); 550 tls_config_insecure_noverifycert(tls_cfg); 551 } 552 if (TLSopt & TLS_MUSTSTAPLE) 553 tls_config_ocsp_require_stapling(tls_cfg); 554 555 if (Pflag) { 556 if (pledge("stdio inet dns tty", NULL) == -1) 557 err(1, "pledge"); 558 } else if (pledge("stdio inet dns", NULL) == -1) 559 err(1, "pledge"); 560 } 561 if (lflag) { 562 ret = 0; 563 564 if (family == AF_UNIX) { 565 if (uflag) 566 s = unix_bind(host, 0); 567 else 568 s = unix_listen(host); 569 } 570 571 if (usetls) { 572 tls_config_verify_client_optional(tls_cfg); 573 if ((tls_ctx = tls_server()) == NULL) 574 errx(1, "tls server creation failed"); 575 if (tls_configure(tls_ctx, tls_cfg) == -1) 576 errx(1, "tls configuration failed (%s)", 577 tls_error(tls_ctx)); 578 } 579 /* Allow only one connection at a time, but stay alive. */ 580 for (;;) { 581 if (family != AF_UNIX) { 582 if (s != -1) 583 close(s); 584 s = local_listen(host, uport, hints); 585 } 586 if (s < 0) 587 err(1, NULL); 588 if (uflag && kflag) { 589 /* 590 * For UDP and -k, don't connect the socket, 591 * let it receive datagrams from multiple 592 * socket pairs. 593 */ 594 readwrite(s, NULL); 595 } else if (uflag && !kflag) { 596 /* 597 * For UDP and not -k, we will use recvfrom() 598 * initially to wait for a caller, then use 599 * the regular functions to talk to the caller. 600 */ 601 int rv; 602 char buf[2048]; 603 struct sockaddr_storage z; 604 605 len = sizeof(z); 606 rv = recvfrom(s, buf, sizeof(buf), MSG_PEEK, 607 (struct sockaddr *)&z, &len); 608 if (rv < 0) 609 err(1, "recvfrom"); 610 611 rv = connect(s, (struct sockaddr *)&z, len); 612 if (rv < 0) 613 err(1, "connect"); 614 615 if (vflag) 616 report_sock("Connection received", 617 (struct sockaddr *)&z, len, NULL); 618 619 readwrite(s, NULL); 620 } else { 621 struct tls *tls_cctx = NULL; 622 int connfd; 623 624 len = sizeof(cliaddr); 625 connfd = accept4(s, (struct sockaddr *)&cliaddr, 626 &len, SOCK_NONBLOCK); 627 if (connfd == -1) { 628 /* For now, all errnos are fatal */ 629 err(1, "accept"); 630 } 631 if (vflag) 632 report_sock("Connection received", 633 (struct sockaddr *)&cliaddr, len, 634 family == AF_UNIX ? host : NULL); 635 if ((usetls) && 636 (tls_cctx = tls_setup_server(tls_ctx, connfd, host))) 637 readwrite(connfd, tls_cctx); 638 if (!usetls) 639 readwrite(connfd, NULL); 640 if (tls_cctx) 641 timeout_tls(s, tls_cctx, tls_close); 642 close(connfd); 643 tls_free(tls_cctx); 644 } 645 if (family == AF_UNIX && uflag) { 646 if (connect(s, NULL, 0) < 0) 647 err(1, "connect"); 648 } 649 650 if (!kflag) 651 break; 652 } 653 } else if (family == AF_UNIX) { 654 ret = 0; 655 656 if ((s = unix_connect(host)) > 0) { 657 if (!zflag) 658 readwrite(s, NULL); 659 close(s); 660 } else { 661 warn("%s", host); 662 ret = 1; 663 } 664 665 if (uflag) 666 unlink(unix_dg_tmp_socket); 667 return ret; 668 669 } else { 670 int i = 0; 671 672 /* Construct the portlist[] array. */ 673 build_ports(uport); 674 675 /* Cycle through portlist, connecting to each port. */ 676 for (s = -1, i = 0; portlist[i] != NULL; i++) { 677 if (s != -1) 678 close(s); 679 tls_free(tls_ctx); 680 tls_ctx = NULL; 681 682 if (usetls) { 683 if ((tls_ctx = tls_client()) == NULL) 684 errx(1, "tls client creation failed"); 685 if (tls_configure(tls_ctx, tls_cfg) == -1) 686 errx(1, "tls configuration failed (%s)", 687 tls_error(tls_ctx)); 688 } 689 if (xflag) 690 s = socks_connect(host, portlist[i], hints, 691 proxy, proxyport, proxyhints, socksv, 692 Pflag); 693 else 694 s = remote_connect(host, portlist[i], hints); 695 696 if (s == -1) 697 continue; 698 699 ret = 0; 700 if (vflag || zflag) { 701 /* For UDP, make sure we are connected. */ 702 if (uflag) { 703 if (udptest(s) == -1) { 704 ret = 1; 705 continue; 706 } 707 } 708 709 /* Don't look up port if -n. */ 710 if (nflag) 711 sv = NULL; 712 else { 713 sv = getservbyport( 714 ntohs(atoi(portlist[i])), 715 uflag ? "udp" : "tcp"); 716 } 717 718 fprintf(stderr, 719 "Connection to %s %s port [%s/%s] " 720 "succeeded!\n", host, portlist[i], 721 uflag ? "udp" : "tcp", 722 sv ? sv->s_name : "*"); 723 } 724 if (Fflag) 725 fdpass(s); 726 else { 727 if (usetls) 728 tls_setup_client(tls_ctx, s, host); 729 if (!zflag) 730 readwrite(s, tls_ctx); 731 if (tls_ctx) 732 timeout_tls(s, tls_ctx, tls_close); 733 } 734 } 735 } 736 737 if (s != -1) 738 close(s); 739 tls_free(tls_ctx); 740 tls_config_free(tls_cfg); 741 742 return ret; 743 } 744 745 /* 746 * unix_bind() 747 * Returns a unix socket bound to the given path 748 */ 749 int 750 unix_bind(char *path, int flags) 751 { 752 struct sockaddr_un s_un; 753 int s, save_errno; 754 755 /* Create unix domain socket. */ 756 if ((s = socket(AF_UNIX, flags | (uflag ? SOCK_DGRAM : SOCK_STREAM), 757 0)) < 0) 758 return -1; 759 760 memset(&s_un, 0, sizeof(struct sockaddr_un)); 761 s_un.sun_family = AF_UNIX; 762 763 if (strlcpy(s_un.sun_path, path, sizeof(s_un.sun_path)) >= 764 sizeof(s_un.sun_path)) { 765 close(s); 766 errno = ENAMETOOLONG; 767 return -1; 768 } 769 770 if (bind(s, (struct sockaddr *)&s_un, sizeof(s_un)) < 0) { 771 save_errno = errno; 772 close(s); 773 errno = save_errno; 774 return -1; 775 } 776 if (vflag) 777 report_sock("Bound", NULL, 0, path); 778 779 return s; 780 } 781 782 int 783 timeout_tls(int s, struct tls *tls_ctx, int (*func)(struct tls *)) 784 { 785 struct pollfd pfd; 786 int ret; 787 788 while ((ret = (*func)(tls_ctx)) != 0) { 789 if (ret == TLS_WANT_POLLIN) 790 pfd.events = POLLIN; 791 else if (ret == TLS_WANT_POLLOUT) 792 pfd.events = POLLOUT; 793 else 794 break; 795 pfd.fd = s; 796 if ((ret = poll(&pfd, 1, timeout)) == 1) 797 continue; 798 else if (ret == 0) { 799 errno = ETIMEDOUT; 800 ret = -1; 801 break; 802 } else 803 err(1, "poll failed"); 804 } 805 806 return ret; 807 } 808 809 void 810 tls_setup_client(struct tls *tls_ctx, int s, char *host) 811 { 812 const char *errstr; 813 814 if (tls_connect_socket(tls_ctx, s, 815 tls_expectname ? tls_expectname : host) == -1) { 816 errx(1, "tls connection failed (%s)", 817 tls_error(tls_ctx)); 818 } 819 if (timeout_tls(s, tls_ctx, tls_handshake) == -1) { 820 if ((errstr = tls_error(tls_ctx)) == NULL) 821 errstr = strerror(errno); 822 errx(1, "tls handshake failed (%s)", errstr); 823 } 824 if (vflag) 825 report_tls(tls_ctx, host); 826 if (tls_expecthash && tls_peer_cert_hash(tls_ctx) && 827 strcmp(tls_expecthash, tls_peer_cert_hash(tls_ctx)) != 0) 828 errx(1, "peer certificate is not %s", tls_expecthash); 829 if (Zflag) { 830 save_peer_cert(tls_ctx, Zflag); 831 if (Zflag != stderr && (fclose(Zflag) != 0)) 832 err(1, "fclose failed saving peer cert"); 833 } 834 } 835 836 struct tls * 837 tls_setup_server(struct tls *tls_ctx, int connfd, char *host) 838 { 839 struct tls *tls_cctx; 840 const char *errstr; 841 842 if (tls_accept_socket(tls_ctx, &tls_cctx, connfd) == -1) { 843 warnx("tls accept failed (%s)", tls_error(tls_ctx)); 844 } else if (timeout_tls(connfd, tls_cctx, tls_handshake) == -1) { 845 if ((errstr = tls_error(tls_cctx)) == NULL) 846 errstr = strerror(errno); 847 warnx("tls handshake failed (%s)", errstr); 848 } else { 849 int gotcert = tls_peer_cert_provided(tls_cctx); 850 851 if (vflag && gotcert) 852 report_tls(tls_cctx, host); 853 if ((TLSopt & TLS_CCERT) && !gotcert) 854 warnx("No client certificate provided"); 855 else if (gotcert && tls_peer_cert_hash(tls_ctx) && tls_expecthash && 856 strcmp(tls_expecthash, tls_peer_cert_hash(tls_ctx)) != 0) 857 warnx("peer certificate is not %s", tls_expecthash); 858 else if (gotcert && tls_expectname && 859 (!tls_peer_cert_contains_name(tls_cctx, tls_expectname))) 860 warnx("name (%s) not found in client cert", 861 tls_expectname); 862 else { 863 return tls_cctx; 864 } 865 } 866 return NULL; 867 } 868 869 /* 870 * unix_connect() 871 * Returns a socket connected to a local unix socket. Returns -1 on failure. 872 */ 873 int 874 unix_connect(char *path) 875 { 876 struct sockaddr_un s_un; 877 int s, save_errno; 878 879 if (uflag) { 880 if ((s = unix_bind(unix_dg_tmp_socket, SOCK_CLOEXEC)) < 0) 881 return -1; 882 } else { 883 if ((s = socket(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC, 0)) < 0) 884 return -1; 885 } 886 887 memset(&s_un, 0, sizeof(struct sockaddr_un)); 888 s_un.sun_family = AF_UNIX; 889 890 if (strlcpy(s_un.sun_path, path, sizeof(s_un.sun_path)) >= 891 sizeof(s_un.sun_path)) { 892 close(s); 893 errno = ENAMETOOLONG; 894 return -1; 895 } 896 if (connect(s, (struct sockaddr *)&s_un, sizeof(s_un)) < 0) { 897 save_errno = errno; 898 close(s); 899 errno = save_errno; 900 return -1; 901 } 902 return s; 903 904 } 905 906 /* 907 * unix_listen() 908 * Create a unix domain socket, and listen on it. 909 */ 910 int 911 unix_listen(char *path) 912 { 913 int s; 914 915 if ((s = unix_bind(path, 0)) < 0) 916 return -1; 917 if (listen(s, 5) < 0) { 918 close(s); 919 return -1; 920 } 921 if (vflag) 922 report_sock("Listening", NULL, 0, path); 923 924 return s; 925 } 926 927 /* 928 * remote_connect() 929 * Returns a socket connected to a remote host. Properly binds to a local 930 * port or source address if needed. Returns -1 on failure. 931 */ 932 int 933 remote_connect(const char *host, const char *port, struct addrinfo hints) 934 { 935 struct addrinfo *res, *res0; 936 int s = -1, error, save_errno; 937 #ifdef SO_BINDANY 938 int on = 1; 939 #endif 940 941 if ((error = getaddrinfo(host, port, &hints, &res0))) 942 errx(1, "getaddrinfo for host \"%s\" port %s: %s", host, 943 port, gai_strerror(error)); 944 945 for (res = res0; res; res = res->ai_next) { 946 if ((s = socket(res->ai_family, res->ai_socktype | 947 SOCK_NONBLOCK, res->ai_protocol)) < 0) 948 continue; 949 950 /* Bind to a local port or source address if specified. */ 951 if (sflag || pflag) { 952 struct addrinfo ahints, *ares; 953 954 #ifdef SO_BINDANY 955 /* try SO_BINDANY, but don't insist */ 956 setsockopt(s, SOL_SOCKET, SO_BINDANY, &on, sizeof(on)); 957 #endif 958 memset(&ahints, 0, sizeof(struct addrinfo)); 959 ahints.ai_family = res->ai_family; 960 ahints.ai_socktype = uflag ? SOCK_DGRAM : SOCK_STREAM; 961 ahints.ai_protocol = uflag ? IPPROTO_UDP : IPPROTO_TCP; 962 ahints.ai_flags = AI_PASSIVE; 963 if ((error = getaddrinfo(sflag, pflag, &ahints, &ares))) 964 errx(1, "getaddrinfo: %s", gai_strerror(error)); 965 966 if (bind(s, (struct sockaddr *)ares->ai_addr, 967 ares->ai_addrlen) < 0) 968 err(1, "bind failed"); 969 freeaddrinfo(ares); 970 } 971 972 set_common_sockopts(s, res->ai_family); 973 974 if (timeout_connect(s, res->ai_addr, res->ai_addrlen) == 0) 975 break; 976 if (vflag) 977 warn("connect to %s port %s (%s) failed", host, port, 978 uflag ? "udp" : "tcp"); 979 980 save_errno = errno; 981 close(s); 982 errno = save_errno; 983 s = -1; 984 } 985 986 freeaddrinfo(res0); 987 988 return s; 989 } 990 991 int 992 timeout_connect(int s, const struct sockaddr *name, socklen_t namelen) 993 { 994 struct pollfd pfd; 995 socklen_t optlen; 996 int optval; 997 int ret; 998 999 if ((ret = connect(s, name, namelen)) != 0 && errno == EINPROGRESS) { 1000 pfd.fd = s; 1001 pfd.events = POLLOUT; 1002 if ((ret = poll(&pfd, 1, timeout)) == 1) { 1003 optlen = sizeof(optval); 1004 if ((ret = getsockopt(s, SOL_SOCKET, SO_ERROR, 1005 &optval, &optlen)) == 0) { 1006 errno = optval; 1007 ret = optval == 0 ? 0 : -1; 1008 } 1009 } else if (ret == 0) { 1010 errno = ETIMEDOUT; 1011 ret = -1; 1012 } else 1013 err(1, "poll failed"); 1014 } 1015 1016 return ret; 1017 } 1018 1019 /* 1020 * local_listen() 1021 * Returns a socket listening on a local port, binds to specified source 1022 * address. Returns -1 on failure. 1023 */ 1024 int 1025 local_listen(const char *host, const char *port, struct addrinfo hints) 1026 { 1027 struct addrinfo *res, *res0; 1028 int s = -1, save_errno; 1029 #ifdef SO_REUSEPORT 1030 int ret, x = 1; 1031 #endif 1032 int error; 1033 1034 /* Allow nodename to be null. */ 1035 hints.ai_flags |= AI_PASSIVE; 1036 1037 /* 1038 * In the case of binding to a wildcard address 1039 * default to binding to an ipv4 address. 1040 */ 1041 if (host == NULL && hints.ai_family == AF_UNSPEC) 1042 hints.ai_family = AF_INET; 1043 1044 if ((error = getaddrinfo(host, port, &hints, &res0))) 1045 errx(1, "getaddrinfo: %s", gai_strerror(error)); 1046 1047 for (res = res0; res; res = res->ai_next) { 1048 if ((s = socket(res->ai_family, res->ai_socktype, 1049 res->ai_protocol)) < 0) 1050 continue; 1051 1052 #ifdef SO_REUSEPORT 1053 ret = setsockopt(s, SOL_SOCKET, SO_REUSEPORT, &x, sizeof(x)); 1054 if (ret == -1) 1055 err(1, NULL); 1056 #endif 1057 1058 set_common_sockopts(s, res->ai_family); 1059 1060 if (bind(s, (struct sockaddr *)res->ai_addr, 1061 res->ai_addrlen) == 0) 1062 break; 1063 1064 save_errno = errno; 1065 close(s); 1066 errno = save_errno; 1067 s = -1; 1068 } 1069 1070 if (!uflag && s != -1) { 1071 if (listen(s, 1) < 0) 1072 err(1, "listen"); 1073 } 1074 if (vflag && s != -1) { 1075 struct sockaddr_storage ss; 1076 socklen_t len; 1077 1078 len = sizeof(ss); 1079 if (getsockname(s, (struct sockaddr *)&ss, &len) == -1) 1080 err(1, "getsockname"); 1081 report_sock(uflag ? "Bound" : "Listening", 1082 (struct sockaddr *)&ss, len, NULL); 1083 } 1084 1085 freeaddrinfo(res0); 1086 1087 return s; 1088 } 1089 1090 /* 1091 * readwrite() 1092 * Loop that polls on the network file descriptor and stdin. 1093 */ 1094 void 1095 readwrite(int net_fd, struct tls *tls_ctx) 1096 { 1097 struct pollfd pfd[4]; 1098 int stdin_fd = STDIN_FILENO; 1099 int stdout_fd = STDOUT_FILENO; 1100 unsigned char netinbuf[BUFSIZE]; 1101 size_t netinbufpos = 0; 1102 unsigned char stdinbuf[BUFSIZE]; 1103 size_t stdinbufpos = 0; 1104 int n, num_fds; 1105 ssize_t ret; 1106 1107 /* don't read from stdin if requested */ 1108 if (dflag) 1109 stdin_fd = -1; 1110 1111 /* stdin */ 1112 pfd[POLL_STDIN].fd = stdin_fd; 1113 pfd[POLL_STDIN].events = POLLIN; 1114 1115 /* network out */ 1116 pfd[POLL_NETOUT].fd = net_fd; 1117 pfd[POLL_NETOUT].events = 0; 1118 1119 /* network in */ 1120 pfd[POLL_NETIN].fd = net_fd; 1121 pfd[POLL_NETIN].events = POLLIN; 1122 1123 /* stdout */ 1124 pfd[POLL_STDOUT].fd = stdout_fd; 1125 pfd[POLL_STDOUT].events = 0; 1126 1127 while (1) { 1128 /* both inputs are gone, buffers are empty, we are done */ 1129 if (pfd[POLL_STDIN].fd == -1 && pfd[POLL_NETIN].fd == -1 && 1130 stdinbufpos == 0 && netinbufpos == 0) 1131 return; 1132 /* both outputs are gone, we can't continue */ 1133 if (pfd[POLL_NETOUT].fd == -1 && pfd[POLL_STDOUT].fd == -1) 1134 return; 1135 /* listen and net in gone, queues empty, done */ 1136 if (lflag && pfd[POLL_NETIN].fd == -1 && 1137 stdinbufpos == 0 && netinbufpos == 0) 1138 return; 1139 1140 /* help says -i is for "wait between lines sent". We read and 1141 * write arbitrary amounts of data, and we don't want to start 1142 * scanning for newlines, so this is as good as it gets */ 1143 if (iflag) 1144 sleep(iflag); 1145 1146 /* poll */ 1147 num_fds = poll(pfd, 4, timeout); 1148 1149 /* treat poll errors */ 1150 if (num_fds == -1) 1151 err(1, "polling error"); 1152 1153 /* timeout happened */ 1154 if (num_fds == 0) 1155 return; 1156 1157 /* treat socket error conditions */ 1158 for (n = 0; n < 4; n++) { 1159 if (pfd[n].revents & (POLLERR|POLLNVAL)) { 1160 pfd[n].fd = -1; 1161 } 1162 } 1163 /* reading is possible after HUP */ 1164 if (pfd[POLL_STDIN].events & POLLIN && 1165 pfd[POLL_STDIN].revents & POLLHUP && 1166 !(pfd[POLL_STDIN].revents & POLLIN)) 1167 pfd[POLL_STDIN].fd = -1; 1168 1169 if (pfd[POLL_NETIN].events & POLLIN && 1170 pfd[POLL_NETIN].revents & POLLHUP && 1171 !(pfd[POLL_NETIN].revents & POLLIN)) 1172 pfd[POLL_NETIN].fd = -1; 1173 1174 if (pfd[POLL_NETOUT].revents & POLLHUP) { 1175 if (Nflag) 1176 shutdown(pfd[POLL_NETOUT].fd, SHUT_WR); 1177 pfd[POLL_NETOUT].fd = -1; 1178 } 1179 /* if HUP, stop watching stdout */ 1180 if (pfd[POLL_STDOUT].revents & POLLHUP) 1181 pfd[POLL_STDOUT].fd = -1; 1182 /* if no net out, stop watching stdin */ 1183 if (pfd[POLL_NETOUT].fd == -1) 1184 pfd[POLL_STDIN].fd = -1; 1185 /* if no stdout, stop watching net in */ 1186 if (pfd[POLL_STDOUT].fd == -1) { 1187 if (pfd[POLL_NETIN].fd != -1) 1188 shutdown(pfd[POLL_NETIN].fd, SHUT_RD); 1189 pfd[POLL_NETIN].fd = -1; 1190 } 1191 1192 /* try to read from stdin */ 1193 if (pfd[POLL_STDIN].revents & POLLIN && stdinbufpos < BUFSIZE) { 1194 ret = fillbuf(pfd[POLL_STDIN].fd, stdinbuf, 1195 &stdinbufpos, NULL); 1196 if (ret == TLS_WANT_POLLIN) 1197 pfd[POLL_STDIN].events = POLLIN; 1198 else if (ret == TLS_WANT_POLLOUT) 1199 pfd[POLL_STDIN].events = POLLOUT; 1200 else if (ret == 0 || ret == -1) 1201 pfd[POLL_STDIN].fd = -1; 1202 /* read something - poll net out */ 1203 if (stdinbufpos > 0) 1204 pfd[POLL_NETOUT].events = POLLOUT; 1205 /* filled buffer - remove self from polling */ 1206 if (stdinbufpos == BUFSIZE) 1207 pfd[POLL_STDIN].events = 0; 1208 } 1209 /* try to write to network */ 1210 if (pfd[POLL_NETOUT].revents & POLLOUT && stdinbufpos > 0) { 1211 ret = drainbuf(pfd[POLL_NETOUT].fd, stdinbuf, 1212 &stdinbufpos, tls_ctx); 1213 if (ret == TLS_WANT_POLLIN) 1214 pfd[POLL_NETOUT].events = POLLIN; 1215 else if (ret == TLS_WANT_POLLOUT) 1216 pfd[POLL_NETOUT].events = POLLOUT; 1217 else if (ret == -1) 1218 pfd[POLL_NETOUT].fd = -1; 1219 /* buffer empty - remove self from polling */ 1220 if (stdinbufpos == 0) 1221 pfd[POLL_NETOUT].events = 0; 1222 /* buffer no longer full - poll stdin again */ 1223 if (stdinbufpos < BUFSIZE) 1224 pfd[POLL_STDIN].events = POLLIN; 1225 } 1226 /* try to read from network */ 1227 if (pfd[POLL_NETIN].revents & POLLIN && netinbufpos < BUFSIZE) { 1228 ret = fillbuf(pfd[POLL_NETIN].fd, netinbuf, 1229 &netinbufpos, tls_ctx); 1230 if (ret == TLS_WANT_POLLIN) 1231 pfd[POLL_NETIN].events = POLLIN; 1232 else if (ret == TLS_WANT_POLLOUT) 1233 pfd[POLL_NETIN].events = POLLOUT; 1234 else if (ret == -1) 1235 pfd[POLL_NETIN].fd = -1; 1236 /* eof on net in - remove from pfd */ 1237 if (ret == 0) { 1238 shutdown(pfd[POLL_NETIN].fd, SHUT_RD); 1239 pfd[POLL_NETIN].fd = -1; 1240 } 1241 if (recvlimit > 0 && ++recvcount >= recvlimit) { 1242 if (pfd[POLL_NETIN].fd != -1) 1243 shutdown(pfd[POLL_NETIN].fd, SHUT_RD); 1244 pfd[POLL_NETIN].fd = -1; 1245 pfd[POLL_STDIN].fd = -1; 1246 } 1247 /* read something - poll stdout */ 1248 if (netinbufpos > 0) 1249 pfd[POLL_STDOUT].events = POLLOUT; 1250 /* filled buffer - remove self from polling */ 1251 if (netinbufpos == BUFSIZE) 1252 pfd[POLL_NETIN].events = 0; 1253 /* handle telnet */ 1254 if (tflag) 1255 atelnet(pfd[POLL_NETIN].fd, netinbuf, 1256 netinbufpos); 1257 } 1258 /* try to write to stdout */ 1259 if (pfd[POLL_STDOUT].revents & POLLOUT && netinbufpos > 0) { 1260 ret = drainbuf(pfd[POLL_STDOUT].fd, netinbuf, 1261 &netinbufpos, NULL); 1262 if (ret == TLS_WANT_POLLIN) 1263 pfd[POLL_STDOUT].events = POLLIN; 1264 else if (ret == TLS_WANT_POLLOUT) 1265 pfd[POLL_STDOUT].events = POLLOUT; 1266 else if (ret == -1) 1267 pfd[POLL_STDOUT].fd = -1; 1268 /* buffer empty - remove self from polling */ 1269 if (netinbufpos == 0) 1270 pfd[POLL_STDOUT].events = 0; 1271 /* buffer no longer full - poll net in again */ 1272 if (netinbufpos < BUFSIZE) 1273 pfd[POLL_NETIN].events = POLLIN; 1274 } 1275 1276 /* stdin gone and queue empty? */ 1277 if (pfd[POLL_STDIN].fd == -1 && stdinbufpos == 0) { 1278 if (pfd[POLL_NETOUT].fd != -1 && Nflag) 1279 shutdown(pfd[POLL_NETOUT].fd, SHUT_WR); 1280 pfd[POLL_NETOUT].fd = -1; 1281 } 1282 /* net in gone and queue empty? */ 1283 if (pfd[POLL_NETIN].fd == -1 && netinbufpos == 0) { 1284 pfd[POLL_STDOUT].fd = -1; 1285 } 1286 } 1287 } 1288 1289 ssize_t 1290 drainbuf(int fd, unsigned char *buf, size_t *bufpos, struct tls *tls) 1291 { 1292 ssize_t n; 1293 ssize_t adjust; 1294 1295 if (tls) { 1296 n = tls_write(tls, buf, *bufpos); 1297 if (n == -1) 1298 errx(1, "tls write failed (%s)", tls_error(tls)); 1299 } else { 1300 n = write(fd, buf, *bufpos); 1301 /* don't treat EAGAIN, EINTR as error */ 1302 if (n == -1 && (errno == EAGAIN || errno == EINTR)) 1303 n = TLS_WANT_POLLOUT; 1304 } 1305 if (n <= 0) 1306 return n; 1307 /* adjust buffer */ 1308 adjust = *bufpos - n; 1309 if (adjust > 0) 1310 memmove(buf, buf + n, adjust); 1311 *bufpos -= n; 1312 return n; 1313 } 1314 1315 ssize_t 1316 fillbuf(int fd, unsigned char *buf, size_t *bufpos, struct tls *tls) 1317 { 1318 size_t num = BUFSIZE - *bufpos; 1319 ssize_t n; 1320 1321 if (tls) { 1322 n = tls_read(tls, buf + *bufpos, num); 1323 if (n == -1) 1324 errx(1, "tls read failed (%s)", tls_error(tls)); 1325 } else { 1326 n = read(fd, buf + *bufpos, num); 1327 /* don't treat EAGAIN, EINTR as error */ 1328 if (n == -1 && (errno == EAGAIN || errno == EINTR)) 1329 n = TLS_WANT_POLLIN; 1330 } 1331 if (n <= 0) 1332 return n; 1333 *bufpos += n; 1334 return n; 1335 } 1336 1337 /* 1338 * fdpass() 1339 * Pass the connected file descriptor to stdout and exit. 1340 */ 1341 void 1342 fdpass(int nfd) 1343 { 1344 struct msghdr mh; 1345 union { 1346 struct cmsghdr hdr; 1347 char buf[CMSG_SPACE(sizeof(int))]; 1348 } cmsgbuf; 1349 struct cmsghdr *cmsg; 1350 struct iovec iov; 1351 char c = '\0'; 1352 ssize_t r; 1353 struct pollfd pfd; 1354 1355 /* Avoid obvious stupidity */ 1356 if (isatty(STDOUT_FILENO)) 1357 errx(1, "Cannot pass file descriptor to tty"); 1358 1359 memset(&mh, 0, sizeof(mh)); 1360 memset(&cmsgbuf, 0, sizeof(cmsgbuf)); 1361 memset(&iov, 0, sizeof(iov)); 1362 1363 mh.msg_control = (caddr_t)&cmsgbuf.buf; 1364 mh.msg_controllen = sizeof(cmsgbuf.buf); 1365 cmsg = CMSG_FIRSTHDR(&mh); 1366 cmsg->cmsg_len = CMSG_LEN(sizeof(int)); 1367 cmsg->cmsg_level = SOL_SOCKET; 1368 cmsg->cmsg_type = SCM_RIGHTS; 1369 *(int *)CMSG_DATA(cmsg) = nfd; 1370 1371 iov.iov_base = &c; 1372 iov.iov_len = 1; 1373 mh.msg_iov = &iov; 1374 mh.msg_iovlen = 1; 1375 1376 memset(&pfd, 0, sizeof(pfd)); 1377 pfd.fd = STDOUT_FILENO; 1378 pfd.events = POLLOUT; 1379 for (;;) { 1380 r = sendmsg(STDOUT_FILENO, &mh, 0); 1381 if (r == -1) { 1382 if (errno == EAGAIN || errno == EINTR) { 1383 if (poll(&pfd, 1, -1) == -1) 1384 err(1, "poll"); 1385 continue; 1386 } 1387 err(1, "sendmsg"); 1388 } else if (r != 1) 1389 errx(1, "sendmsg: unexpected return value %zd", r); 1390 else 1391 break; 1392 } 1393 exit(0); 1394 } 1395 1396 /* Deal with RFC 854 WILL/WONT DO/DONT negotiation. */ 1397 void 1398 atelnet(int nfd, unsigned char *buf, unsigned int size) 1399 { 1400 unsigned char *p, *end; 1401 unsigned char obuf[4]; 1402 1403 if (size < 3) 1404 return; 1405 end = buf + size - 2; 1406 1407 for (p = buf; p < end; p++) { 1408 if (*p != IAC) 1409 continue; 1410 1411 obuf[0] = IAC; 1412 p++; 1413 if ((*p == WILL) || (*p == WONT)) 1414 obuf[1] = DONT; 1415 else if ((*p == DO) || (*p == DONT)) 1416 obuf[1] = WONT; 1417 else 1418 continue; 1419 1420 p++; 1421 obuf[2] = *p; 1422 if (atomicio(vwrite, nfd, obuf, 3) != 3) 1423 warn("Write Error!"); 1424 } 1425 } 1426 1427 1428 int 1429 strtoport(char *portstr, int udp) 1430 { 1431 struct servent *entry; 1432 const char *errstr; 1433 char *proto; 1434 int port = -1; 1435 1436 proto = udp ? "udp" : "tcp"; 1437 1438 port = strtonum(portstr, 1, PORT_MAX, &errstr); 1439 if (errstr == NULL) 1440 return port; 1441 if (errno != EINVAL) 1442 errx(1, "port number %s: %s", errstr, portstr); 1443 if ((entry = getservbyname(portstr, proto)) == NULL) 1444 errx(1, "service \"%s\" unknown", portstr); 1445 return ntohs(entry->s_port); 1446 } 1447 1448 /* 1449 * build_ports() 1450 * Build an array of ports in portlist[], listing each port 1451 * that we should try to connect to. 1452 */ 1453 void 1454 build_ports(char *p) 1455 { 1456 char *n; 1457 int hi, lo, cp; 1458 int x = 0; 1459 1460 if (isdigit((unsigned char)*p) && (n = strchr(p, '-')) != NULL) { 1461 *n = '\0'; 1462 n++; 1463 1464 /* Make sure the ports are in order: lowest->highest. */ 1465 hi = strtoport(n, uflag); 1466 lo = strtoport(p, uflag); 1467 if (lo > hi) { 1468 cp = hi; 1469 hi = lo; 1470 lo = cp; 1471 } 1472 1473 /* 1474 * Initialize portlist with a random permutation. Based on 1475 * Knuth, as in ip_randomid() in sys/netinet/ip_id.c. 1476 */ 1477 if (rflag) { 1478 for (x = 0; x <= hi - lo; x++) { 1479 cp = arc4random_uniform(x + 1); 1480 portlist[x] = portlist[cp]; 1481 if (asprintf(&portlist[cp], "%d", x + lo) < 0) 1482 err(1, "asprintf"); 1483 } 1484 } else { /* Load ports sequentially. */ 1485 for (cp = lo; cp <= hi; cp++) { 1486 if (asprintf(&portlist[x], "%d", cp) < 0) 1487 err(1, "asprintf"); 1488 x++; 1489 } 1490 } 1491 } else { 1492 char *tmp; 1493 1494 hi = strtoport(p, uflag); 1495 if (asprintf(&tmp, "%d", hi) != -1) 1496 portlist[0] = tmp; 1497 else 1498 err(1, NULL); 1499 } 1500 } 1501 1502 /* 1503 * udptest() 1504 * Do a few writes to see if the UDP port is there. 1505 * Fails once PF state table is full. 1506 */ 1507 int 1508 udptest(int s) 1509 { 1510 int i, ret; 1511 1512 for (i = 0; i <= 3; i++) { 1513 if (write(s, "X", 1) == 1) 1514 ret = 1; 1515 else 1516 ret = -1; 1517 } 1518 return ret; 1519 } 1520 1521 void 1522 set_common_sockopts(int s, int af) 1523 { 1524 int x = 1; 1525 1526 #ifdef TCP_MD5SIG 1527 if (Sflag) { 1528 if (setsockopt(s, IPPROTO_TCP, TCP_MD5SIG, 1529 &x, sizeof(x)) == -1) 1530 err(1, NULL); 1531 } 1532 #endif 1533 if (Dflag) { 1534 if (setsockopt(s, SOL_SOCKET, SO_DEBUG, 1535 &x, sizeof(x)) == -1) 1536 err(1, NULL); 1537 } 1538 if (Tflag != -1) { 1539 if (af == AF_INET && setsockopt(s, IPPROTO_IP, 1540 IP_TOS, &Tflag, sizeof(Tflag)) == -1) 1541 err(1, "set IP ToS"); 1542 1543 #ifdef IPV6_TCLASS 1544 else if (af == AF_INET6 && setsockopt(s, IPPROTO_IPV6, 1545 IPV6_TCLASS, &Tflag, sizeof(Tflag)) == -1) 1546 err(1, "set IPv6 traffic class"); 1547 #else 1548 else if (af == AF_INET6) { 1549 errno = ENOPROTOOPT; 1550 err(1, "set IPv6 traffic class not supported"); 1551 } 1552 #endif 1553 } 1554 if (Iflag) { 1555 if (setsockopt(s, SOL_SOCKET, SO_RCVBUF, 1556 &Iflag, sizeof(Iflag)) == -1) 1557 err(1, "set TCP receive buffer size"); 1558 } 1559 if (Oflag) { 1560 if (setsockopt(s, SOL_SOCKET, SO_SNDBUF, 1561 &Oflag, sizeof(Oflag)) == -1) 1562 err(1, "set TCP send buffer size"); 1563 } 1564 1565 if (ttl != -1) { 1566 if (af == AF_INET && setsockopt(s, IPPROTO_IP, 1567 IP_TTL, &ttl, sizeof(ttl))) 1568 err(1, "set IP TTL"); 1569 1570 else if (af == AF_INET6 && setsockopt(s, IPPROTO_IPV6, 1571 IPV6_UNICAST_HOPS, &ttl, sizeof(ttl))) 1572 err(1, "set IPv6 unicast hops"); 1573 } 1574 1575 if (minttl != -1) { 1576 #ifdef IP_MINTTL 1577 if (af == AF_INET && setsockopt(s, IPPROTO_IP, 1578 IP_MINTTL, &minttl, sizeof(minttl))) 1579 err(1, "set IP min TTL"); 1580 #endif 1581 1582 #ifdef IPV6_MINHOPCOUNT 1583 if (af == AF_INET6 && setsockopt(s, IPPROTO_IPV6, 1584 IPV6_MINHOPCOUNT, &minttl, sizeof(minttl))) 1585 err(1, "set IPv6 min hop count"); 1586 #endif 1587 } 1588 } 1589 1590 int 1591 process_tos_opt(char *s, int *val) 1592 { 1593 /* DiffServ Codepoints and other TOS mappings */ 1594 const struct toskeywords { 1595 const char *keyword; 1596 int val; 1597 } *t, toskeywords[] = { 1598 { "af11", IPTOS_DSCP_AF11 }, 1599 { "af12", IPTOS_DSCP_AF12 }, 1600 { "af13", IPTOS_DSCP_AF13 }, 1601 { "af21", IPTOS_DSCP_AF21 }, 1602 { "af22", IPTOS_DSCP_AF22 }, 1603 { "af23", IPTOS_DSCP_AF23 }, 1604 { "af31", IPTOS_DSCP_AF31 }, 1605 { "af32", IPTOS_DSCP_AF32 }, 1606 { "af33", IPTOS_DSCP_AF33 }, 1607 { "af41", IPTOS_DSCP_AF41 }, 1608 { "af42", IPTOS_DSCP_AF42 }, 1609 { "af43", IPTOS_DSCP_AF43 }, 1610 { "critical", IPTOS_PREC_CRITIC_ECP }, 1611 { "cs0", IPTOS_DSCP_CS0 }, 1612 { "cs1", IPTOS_DSCP_CS1 }, 1613 { "cs2", IPTOS_DSCP_CS2 }, 1614 { "cs3", IPTOS_DSCP_CS3 }, 1615 { "cs4", IPTOS_DSCP_CS4 }, 1616 { "cs5", IPTOS_DSCP_CS5 }, 1617 { "cs6", IPTOS_DSCP_CS6 }, 1618 { "cs7", IPTOS_DSCP_CS7 }, 1619 { "ef", IPTOS_DSCP_EF }, 1620 { "inetcontrol", IPTOS_PREC_INTERNETCONTROL }, 1621 { "lowdelay", IPTOS_LOWDELAY }, 1622 { "netcontrol", IPTOS_PREC_NETCONTROL }, 1623 { "reliability", IPTOS_RELIABILITY }, 1624 { "throughput", IPTOS_THROUGHPUT }, 1625 { NULL, -1 }, 1626 }; 1627 1628 for (t = toskeywords; t->keyword != NULL; t++) { 1629 if (strcmp(s, t->keyword) == 0) { 1630 *val = t->val; 1631 return 1; 1632 } 1633 } 1634 1635 return 0; 1636 } 1637 1638 int 1639 process_tls_opt(char *s, int *flags) 1640 { 1641 size_t len; 1642 char *v; 1643 1644 const struct tlskeywords { 1645 const char *keyword; 1646 int flag; 1647 char **value; 1648 } *t, tlskeywords[] = { 1649 { "ciphers", -1, &tls_ciphers }, 1650 { "clientcert", TLS_CCERT, NULL }, 1651 { "muststaple", TLS_MUSTSTAPLE, NULL }, 1652 { "noverify", TLS_NOVERIFY, NULL }, 1653 { "noname", TLS_NONAME, NULL }, 1654 { "protocols", -1, &tls_protocols }, 1655 { NULL, -1, NULL }, 1656 }; 1657 1658 len = strlen(s); 1659 if ((v = strchr(s, '=')) != NULL) { 1660 len = v - s; 1661 v++; 1662 } 1663 1664 for (t = tlskeywords; t->keyword != NULL; t++) { 1665 if (strlen(t->keyword) == len && 1666 strncmp(s, t->keyword, len) == 0) { 1667 if (t->value != NULL) { 1668 if (v == NULL) 1669 errx(1, "invalid tls value `%s'", s); 1670 *t->value = v; 1671 } else { 1672 *flags |= t->flag; 1673 } 1674 return 1; 1675 } 1676 } 1677 return 0; 1678 } 1679 1680 void 1681 save_peer_cert(struct tls *tls_ctx, FILE *fp) 1682 { 1683 const char *pem; 1684 size_t plen; 1685 1686 if ((pem = tls_peer_cert_chain_pem(tls_ctx, &plen)) == NULL) 1687 errx(1, "Can't get peer certificate"); 1688 if (fprintf(fp, "%.*s", (int)plen, pem) < 0) 1689 err(1, "unable to save peer cert"); 1690 if (fflush(fp) != 0) 1691 err(1, "unable to flush peer cert"); 1692 } 1693 1694 void 1695 report_tls(struct tls * tls_ctx, char * host) 1696 { 1697 time_t t; 1698 const char *ocsp_url; 1699 1700 fprintf(stderr, "TLS handshake negotiated %s/%s with host %s\n", 1701 tls_conn_version(tls_ctx), tls_conn_cipher(tls_ctx), host); 1702 fprintf(stderr, "Peer name: %s\n", 1703 tls_expectname ? tls_expectname : host); 1704 if (tls_peer_cert_subject(tls_ctx)) 1705 fprintf(stderr, "Subject: %s\n", 1706 tls_peer_cert_subject(tls_ctx)); 1707 if (tls_peer_cert_issuer(tls_ctx)) 1708 fprintf(stderr, "Issuer: %s\n", 1709 tls_peer_cert_issuer(tls_ctx)); 1710 if ((t = tls_peer_cert_notbefore(tls_ctx)) != -1) 1711 fprintf(stderr, "Valid From: %s", ctime(&t)); 1712 if ((t = tls_peer_cert_notafter(tls_ctx)) != -1) 1713 fprintf(stderr, "Valid Until: %s", ctime(&t)); 1714 if (tls_peer_cert_hash(tls_ctx)) 1715 fprintf(stderr, "Cert Hash: %s\n", 1716 tls_peer_cert_hash(tls_ctx)); 1717 ocsp_url = tls_peer_ocsp_url(tls_ctx); 1718 if (ocsp_url != NULL) 1719 fprintf(stderr, "OCSP URL: %s\n", ocsp_url); 1720 switch (tls_peer_ocsp_response_status(tls_ctx)) { 1721 case TLS_OCSP_RESPONSE_SUCCESSFUL: 1722 fprintf(stderr, "OCSP Stapling: %s\n", 1723 tls_peer_ocsp_result(tls_ctx) == NULL ? "" : 1724 tls_peer_ocsp_result(tls_ctx)); 1725 fprintf(stderr, 1726 " response_status=%d cert_status=%d crl_reason=%d\n", 1727 tls_peer_ocsp_response_status(tls_ctx), 1728 tls_peer_ocsp_cert_status(tls_ctx), 1729 tls_peer_ocsp_crl_reason(tls_ctx)); 1730 t = tls_peer_ocsp_this_update(tls_ctx); 1731 fprintf(stderr, " this update: %s", 1732 t != -1 ? ctime(&t) : "\n"); 1733 t = tls_peer_ocsp_next_update(tls_ctx); 1734 fprintf(stderr, " next update: %s", 1735 t != -1 ? ctime(&t) : "\n"); 1736 t = tls_peer_ocsp_revocation_time(tls_ctx); 1737 fprintf(stderr, " revocation: %s", 1738 t != -1 ? ctime(&t) : "\n"); 1739 break; 1740 case -1: 1741 break; 1742 default: 1743 fprintf(stderr, "OCSP Stapling: failure - response_status %d (%s)\n", 1744 tls_peer_ocsp_response_status(tls_ctx), 1745 tls_peer_ocsp_result(tls_ctx) == NULL ? "" : 1746 tls_peer_ocsp_result(tls_ctx)); 1747 break; 1748 1749 } 1750 } 1751 1752 void 1753 report_sock(const char *msg, const struct sockaddr *sa, socklen_t salen, 1754 char *path) 1755 { 1756 char host[NI_MAXHOST], port[NI_MAXSERV]; 1757 int herr; 1758 int flags = NI_NUMERICSERV; 1759 1760 if (path != NULL) { 1761 fprintf(stderr, "%s on %s\n", msg, path); 1762 return; 1763 } 1764 1765 if (nflag) 1766 flags |= NI_NUMERICHOST; 1767 1768 if ((herr = getnameinfo(sa, salen, host, sizeof(host), 1769 port, sizeof(port), flags)) != 0) { 1770 if (herr == EAI_SYSTEM) 1771 err(1, "getnameinfo"); 1772 else 1773 errx(1, "getnameinfo: %s", gai_strerror(herr)); 1774 } 1775 1776 fprintf(stderr, "%s on %s %s\n", msg, host, port); 1777 } 1778 1779 void 1780 help(void) 1781 { 1782 usage(0); 1783 fprintf(stderr, "\tCommand Summary:\n\ 1784 \t-4 Use IPv4\n\ 1785 \t-6 Use IPv6\n\ 1786 \t-C certfile Public key file\n\ 1787 \t-c Use TLS\n\ 1788 \t-D Enable the debug socket option\n\ 1789 \t-d Detach from stdin\n\ 1790 \t-e name\t Required name in peer certificate\n\ 1791 \t-F Pass socket fd\n\ 1792 \t-H hash\t Hash string of peer certificate\n\ 1793 \t-h This help text\n\ 1794 \t-I length TCP receive buffer length\n\ 1795 \t-i interval Delay interval for lines sent, ports scanned\n\ 1796 \t-K keyfile Private key file\n\ 1797 \t-k Keep inbound sockets open for multiple connects\n\ 1798 \t-l Listen mode, for inbound connects\n\ 1799 \t-M ttl Outgoing TTL / Hop Limit\n\ 1800 \t-m minttl Minimum incoming TTL / Hop Limit\n\ 1801 \t-N Shutdown the network socket after EOF on stdin\n\ 1802 \t-n Suppress name/port resolutions\n\ 1803 \t-O length TCP send buffer length\n\ 1804 \t-o staplefile Staple file\n\ 1805 \t-P proxyuser\tUsername for proxy authentication\n\ 1806 \t-p port\t Specify local port for remote connects\n\ 1807 \t-R CAfile CA bundle\n\ 1808 \t-r Randomize remote ports\n" 1809 #ifdef TCP_MD5SIG 1810 "\ 1811 \t-S Enable the TCP MD5 signature option\n" 1812 #endif 1813 "\ 1814 \t-s source Local source address\n\ 1815 \t-T keyword TOS value or TLS options\n\ 1816 \t-t Answer TELNET negotiation\n\ 1817 \t-U Use UNIX domain socket\n\ 1818 \t-u UDP mode\n" 1819 #ifdef SO_RTABLE 1820 "\ 1821 \t-V rtable Specify alternate routing table\n" 1822 #endif 1823 "\ 1824 \t-v Verbose\n\ 1825 \t-W recvlimit Terminate after receiving a number of packets\n\ 1826 \t-w timeout Timeout for connects and final net reads\n\ 1827 \t-X proto Proxy protocol: \"4\", \"5\" (SOCKS) or \"connect\"\n\ 1828 \t-x addr[:port]\tSpecify proxy address and port\n\ 1829 \t-Z Peer certificate file\n\ 1830 \t-z Zero-I/O mode [used for scanning]\n\ 1831 Port numbers can be individual or ranges: lo-hi [inclusive]\n"); 1832 exit(1); 1833 } 1834 1835 void 1836 usage(int ret) 1837 { 1838 fprintf(stderr, 1839 "usage: nc [-46cDdFhklNnrStUuvz] [-C certfile] [-e name] " 1840 "[-H hash] [-I length]\n" 1841 "\t [-i interval] [-K keyfile] [-M ttl] [-m minttl] [-O length]\n" 1842 "\t [-o staplefile] [-P proxy_username] [-p source_port] " 1843 "[-R CAfile]\n" 1844 "\t [-s source] [-T keyword] [-V rtable] [-W recvlimit] " 1845 "[-w timeout]\n" 1846 "\t [-X proxy_protocol] [-x proxy_address[:port]] " 1847 "[-Z peercertfile]\n" 1848 "\t [destination] [port]\n"); 1849 if (ret) 1850 exit(1); 1851 } 1852