1 /* $OpenBSD: netcat.c,v 1.187 2017/07/15 17:27:39 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 <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 <tls.h> 57 #include <unistd.h> 58 59 #include "atomicio.h" 60 61 #define PORT_MAX 65535 62 #define UNIX_DG_TMP_SOCKET_SIZE 19 63 64 #define POLL_STDIN 0 65 #define POLL_NETOUT 1 66 #define POLL_NETIN 2 67 #define POLL_STDOUT 3 68 #define BUFSIZE 16384 69 #define DEFAULT_CA_FILE "/etc/ssl/cert.pem" 70 71 #define TLS_ALL (1 << 1) 72 #define TLS_NOVERIFY (1 << 2) 73 #define TLS_NONAME (1 << 3) 74 #define TLS_CCERT (1 << 4) 75 #define TLS_MUSTSTAPLE (1 << 5) 76 #define TLS_COMPAT (1 << 6) 77 78 /* Command Line Options */ 79 int dflag; /* detached, no stdin */ 80 int Fflag; /* fdpass sock to stdout */ 81 unsigned int iflag; /* Interval Flag */ 82 int kflag; /* More than one connect */ 83 int lflag; /* Bind to local port */ 84 int Nflag; /* shutdown() network socket */ 85 int nflag; /* Don't do name look up */ 86 char *Pflag; /* Proxy username */ 87 char *pflag; /* Localport flag */ 88 int rflag; /* Random ports flag */ 89 char *sflag; /* Source Address */ 90 int tflag; /* Telnet Emulation */ 91 int uflag; /* UDP - Default to TCP */ 92 int vflag; /* Verbosity */ 93 int xflag; /* Socks proxy */ 94 int zflag; /* Port Scan Flag */ 95 int Dflag; /* sodebug */ 96 int Iflag; /* TCP receive buffer size */ 97 int Oflag; /* TCP send buffer size */ 98 int Sflag; /* TCP MD5 signature option */ 99 int Tflag = -1; /* IP Type of Service */ 100 int rtableid = -1; 101 102 int usetls; /* use TLS */ 103 char *Cflag; /* Public cert file */ 104 char *Kflag; /* Private key file */ 105 char *oflag; /* OCSP stapling file */ 106 char *Rflag = DEFAULT_CA_FILE; /* Root CA file */ 107 int tls_cachanged; /* Using non-default CA file */ 108 int TLSopt; /* TLS options */ 109 char *tls_expectname; /* required name in peer cert */ 110 char *tls_expecthash; /* required hash of peer cert */ 111 FILE *Zflag; /* file to save peer cert */ 112 113 int recvcount, recvlimit; 114 int timeout = -1; 115 int family = AF_UNSPEC; 116 char *portlist[PORT_MAX+1]; 117 char *unix_dg_tmp_socket; 118 int ttl = -1; 119 int minttl = -1; 120 121 void atelnet(int, unsigned char *, unsigned int); 122 int strtoport(char *portstr, int udp); 123 void build_ports(char *); 124 void help(void) __attribute__((noreturn)); 125 int local_listen(char *, char *, struct addrinfo); 126 void readwrite(int, struct tls *); 127 void fdpass(int nfd) __attribute__((noreturn)); 128 int remote_connect(const char *, const char *, struct addrinfo); 129 int timeout_tls(int, struct tls *, int (*)(struct tls *)); 130 int timeout_connect(int, const struct sockaddr *, socklen_t); 131 int socks_connect(const char *, const char *, struct addrinfo, 132 const char *, const char *, struct addrinfo, int, const char *); 133 int udptest(int); 134 int unix_bind(char *, int); 135 int unix_connect(char *); 136 int unix_listen(char *); 137 void set_common_sockopts(int, int); 138 int map_tos(char *, int *); 139 int map_tls(char *, int *); 140 void save_peer_cert(struct tls *_tls_ctx, FILE *_fp); 141 void report_connect(const struct sockaddr *, socklen_t, char *); 142 void report_tls(struct tls *tls_ctx, char * host); 143 void usage(int); 144 ssize_t drainbuf(int, unsigned char *, size_t *, struct tls *); 145 ssize_t fillbuf(int, unsigned char *, size_t *, struct tls *); 146 void tls_setup_client(struct tls *, int, char *); 147 struct tls *tls_setup_server(struct tls *, int, char *); 148 149 int 150 main(int argc, char *argv[]) 151 { 152 int ch, s = -1, ret, socksv; 153 char *host, *uport; 154 struct addrinfo hints; 155 struct servent *sv; 156 socklen_t len; 157 struct sockaddr_storage cliaddr; 158 char *proxy = NULL, *proxyport = NULL; 159 const char *errstr; 160 struct addrinfo proxyhints; 161 char unix_dg_tmp_socket_buf[UNIX_DG_TMP_SOCKET_SIZE]; 162 struct tls_config *tls_cfg = NULL; 163 struct tls *tls_ctx = NULL; 164 165 ret = 1; 166 socksv = 5; 167 host = NULL; 168 uport = NULL; 169 sv = NULL; 170 171 signal(SIGPIPE, SIG_IGN); 172 173 while ((ch = getopt(argc, argv, 174 "46C:cDde:FH:hI:i:K:klM:m:NnO:o:P:p:R:rSs:T:tUuV:vW:w:X:x:Z:z")) 175 != -1) { 176 switch (ch) { 177 case '4': 178 family = AF_INET; 179 break; 180 case '6': 181 family = AF_INET6; 182 break; 183 case 'U': 184 family = AF_UNIX; 185 break; 186 case 'X': 187 if (strcasecmp(optarg, "connect") == 0) 188 socksv = -1; /* HTTP proxy CONNECT */ 189 else if (strcmp(optarg, "4") == 0) 190 socksv = 4; /* SOCKS v.4 */ 191 else if (strcmp(optarg, "5") == 0) 192 socksv = 5; /* SOCKS v.5 */ 193 else 194 errx(1, "unsupported proxy protocol"); 195 break; 196 case 'C': 197 Cflag = optarg; 198 break; 199 case 'c': 200 usetls = 1; 201 break; 202 case 'd': 203 dflag = 1; 204 break; 205 case 'e': 206 tls_expectname = optarg; 207 break; 208 case 'F': 209 Fflag = 1; 210 break; 211 case 'H': 212 tls_expecthash = optarg; 213 break; 214 case 'h': 215 help(); 216 break; 217 case 'i': 218 iflag = strtonum(optarg, 0, UINT_MAX, &errstr); 219 if (errstr) 220 errx(1, "interval %s: %s", errstr, optarg); 221 break; 222 case 'K': 223 Kflag = optarg; 224 break; 225 case 'k': 226 kflag = 1; 227 break; 228 case 'l': 229 lflag = 1; 230 break; 231 case 'M': 232 ttl = strtonum(optarg, 0, 255, &errstr); 233 if (errstr) 234 errx(1, "ttl is %s", errstr); 235 break; 236 case 'm': 237 minttl = strtonum(optarg, 0, 255, &errstr); 238 if (errstr) 239 errx(1, "minttl is %s", errstr); 240 break; 241 case 'N': 242 Nflag = 1; 243 break; 244 case 'n': 245 nflag = 1; 246 break; 247 case 'P': 248 Pflag = optarg; 249 break; 250 case 'p': 251 pflag = optarg; 252 break; 253 case 'R': 254 tls_cachanged = 1; 255 Rflag = optarg; 256 break; 257 case 'r': 258 rflag = 1; 259 break; 260 case 's': 261 sflag = optarg; 262 break; 263 case 't': 264 tflag = 1; 265 break; 266 case 'u': 267 uflag = 1; 268 break; 269 case 'V': 270 rtableid = (int)strtonum(optarg, 0, 271 RT_TABLEID_MAX, &errstr); 272 if (errstr) 273 errx(1, "rtable %s: %s", errstr, optarg); 274 break; 275 case 'v': 276 vflag = 1; 277 break; 278 case 'W': 279 recvlimit = strtonum(optarg, 1, INT_MAX, &errstr); 280 if (errstr) 281 errx(1, "receive limit %s: %s", errstr, optarg); 282 break; 283 case 'w': 284 timeout = strtonum(optarg, 0, INT_MAX / 1000, &errstr); 285 if (errstr) 286 errx(1, "timeout %s: %s", errstr, optarg); 287 timeout *= 1000; 288 break; 289 case 'x': 290 xflag = 1; 291 if ((proxy = strdup(optarg)) == NULL) 292 err(1, NULL); 293 break; 294 case 'Z': 295 if (strcmp(optarg, "-") == 0) 296 Zflag = stderr; 297 else if ((Zflag = fopen(optarg, "w")) == NULL) 298 err(1, "can't open %s", optarg); 299 break; 300 case 'z': 301 zflag = 1; 302 break; 303 case 'D': 304 Dflag = 1; 305 break; 306 case 'I': 307 Iflag = strtonum(optarg, 1, 65536 << 14, &errstr); 308 if (errstr != NULL) 309 errx(1, "TCP receive window %s: %s", 310 errstr, optarg); 311 break; 312 case 'O': 313 Oflag = strtonum(optarg, 1, 65536 << 14, &errstr); 314 if (errstr != NULL) 315 errx(1, "TCP send window %s: %s", 316 errstr, optarg); 317 break; 318 case 'o': 319 oflag = optarg; 320 break; 321 case 'S': 322 Sflag = 1; 323 break; 324 case 'T': 325 errstr = NULL; 326 errno = 0; 327 if (map_tos(optarg, &Tflag)) 328 break; 329 if (map_tls(optarg, &TLSopt)) 330 break; 331 if (strlen(optarg) > 1 && optarg[0] == '0' && 332 optarg[1] == 'x') 333 Tflag = (int)strtol(optarg, NULL, 16); 334 else 335 Tflag = (int)strtonum(optarg, 0, 255, 336 &errstr); 337 if (Tflag < 0 || Tflag > 255 || errstr || errno) 338 errx(1, "illegal tos/tls value %s", optarg); 339 break; 340 default: 341 usage(1); 342 } 343 } 344 argc -= optind; 345 argv += optind; 346 347 if (rtableid >= 0) 348 if (setrtable(rtableid) == -1) 349 err(1, "setrtable"); 350 351 if (family == AF_UNIX) { 352 if (pledge("stdio rpath wpath cpath tmppath unix", NULL) == -1) 353 err(1, "pledge"); 354 } else if (Fflag && Pflag) { 355 if (pledge("stdio inet dns sendfd tty", NULL) == -1) 356 err(1, "pledge"); 357 } else if (Fflag) { 358 if (pledge("stdio inet dns sendfd", NULL) == -1) 359 err(1, "pledge"); 360 } else if (Pflag && usetls) { 361 if (pledge("stdio rpath inet dns tty", NULL) == -1) 362 err(1, "pledge"); 363 } else if (Pflag) { 364 if (pledge("stdio inet dns tty", NULL) == -1) 365 err(1, "pledge"); 366 } else if (usetls) { 367 if (pledge("stdio rpath inet dns", NULL) == -1) 368 err(1, "pledge"); 369 } else if (pledge("stdio inet dns", NULL) == -1) 370 err(1, "pledge"); 371 372 /* Cruft to make sure options are clean, and used properly. */ 373 if (argv[0] && !argv[1] && family == AF_UNIX) { 374 host = argv[0]; 375 uport = NULL; 376 } else if (argv[0] && !argv[1]) { 377 if (!lflag) 378 usage(1); 379 uport = argv[0]; 380 host = NULL; 381 } else if (argv[0] && argv[1]) { 382 host = argv[0]; 383 uport = argv[1]; 384 } else 385 usage(1); 386 387 if (lflag && sflag) 388 errx(1, "cannot use -s and -l"); 389 if (lflag && pflag) 390 errx(1, "cannot use -p and -l"); 391 if (lflag && zflag) 392 errx(1, "cannot use -z and -l"); 393 if (!lflag && kflag) 394 errx(1, "must use -l with -k"); 395 if (uflag && usetls) 396 errx(1, "cannot use -c and -u"); 397 if ((family == AF_UNIX) && usetls) 398 errx(1, "cannot use -c and -U"); 399 if ((family == AF_UNIX) && Fflag) 400 errx(1, "cannot use -F and -U"); 401 if (Fflag && usetls) 402 errx(1, "cannot use -c and -F"); 403 if (TLSopt && !usetls) 404 errx(1, "you must specify -c to use TLS options"); 405 if ((TLSopt & (TLS_ALL|TLS_COMPAT)) == (TLS_ALL|TLS_COMPAT)) 406 errx(1, "cannot use -T tlsall and -T tlscompat"); 407 if (Cflag && !usetls) 408 errx(1, "you must specify -c to use -C"); 409 if (Kflag && !usetls) 410 errx(1, "you must specify -c to use -K"); 411 if (Zflag && !usetls) 412 errx(1, "you must specify -c to use -Z"); 413 if (oflag && !Cflag) 414 errx(1, "you must specify -C to use -o"); 415 if (tls_cachanged && !usetls) 416 errx(1, "you must specify -c to use -R"); 417 if (tls_expecthash && !usetls) 418 errx(1, "you must specify -c to use -H"); 419 if (tls_expectname && !usetls) 420 errx(1, "you must specify -c to use -e"); 421 422 /* Get name of temporary socket for unix datagram client */ 423 if ((family == AF_UNIX) && uflag && !lflag) { 424 if (sflag) { 425 unix_dg_tmp_socket = sflag; 426 } else { 427 strlcpy(unix_dg_tmp_socket_buf, "/tmp/nc.XXXXXXXXXX", 428 UNIX_DG_TMP_SOCKET_SIZE); 429 if (mktemp(unix_dg_tmp_socket_buf) == NULL) 430 err(1, "mktemp"); 431 unix_dg_tmp_socket = unix_dg_tmp_socket_buf; 432 } 433 } 434 435 /* Initialize addrinfo structure. */ 436 if (family != AF_UNIX) { 437 memset(&hints, 0, sizeof(struct addrinfo)); 438 hints.ai_family = family; 439 hints.ai_socktype = uflag ? SOCK_DGRAM : SOCK_STREAM; 440 hints.ai_protocol = uflag ? IPPROTO_UDP : IPPROTO_TCP; 441 if (nflag) 442 hints.ai_flags |= AI_NUMERICHOST; 443 } 444 445 if (xflag) { 446 if (uflag) 447 errx(1, "no proxy support for UDP mode"); 448 449 if (lflag) 450 errx(1, "no proxy support for listen"); 451 452 if (family == AF_UNIX) 453 errx(1, "no proxy support for unix sockets"); 454 455 if (sflag) 456 errx(1, "no proxy support for local source address"); 457 458 if (*proxy == '[') { 459 ++proxy; 460 proxyport = strchr(proxy, ']'); 461 if (proxyport == NULL) 462 errx(1, "missing closing bracket in proxy"); 463 *proxyport++ = '\0'; 464 if (*proxyport == '\0') 465 /* Use default proxy port. */ 466 proxyport = NULL; 467 else { 468 if (*proxyport == ':') 469 ++proxyport; 470 else 471 errx(1, "garbage proxy port delimiter"); 472 } 473 } else { 474 proxyport = strrchr(proxy, ':'); 475 if (proxyport != NULL) 476 *proxyport++ = '\0'; 477 } 478 479 memset(&proxyhints, 0, sizeof(struct addrinfo)); 480 proxyhints.ai_family = family; 481 proxyhints.ai_socktype = SOCK_STREAM; 482 proxyhints.ai_protocol = IPPROTO_TCP; 483 if (nflag) 484 proxyhints.ai_flags |= AI_NUMERICHOST; 485 } 486 487 if (usetls) { 488 if (tls_init() == -1) 489 errx(1, "unable to initialize TLS"); 490 if ((tls_cfg = tls_config_new()) == NULL) 491 errx(1, "unable to allocate TLS config"); 492 if (Rflag && tls_config_set_ca_file(tls_cfg, Rflag) == -1) 493 errx(1, "%s", tls_config_error(tls_cfg)); 494 if (Cflag && tls_config_set_cert_file(tls_cfg, Cflag) == -1) 495 errx(1, "%s", tls_config_error(tls_cfg)); 496 if (Kflag && tls_config_set_key_file(tls_cfg, Kflag) == -1) 497 errx(1, "%s", tls_config_error(tls_cfg)); 498 if (oflag && tls_config_set_ocsp_staple_file(tls_cfg, oflag) == -1) 499 errx(1, "%s", tls_config_error(tls_cfg)); 500 if (TLSopt & (TLS_ALL|TLS_COMPAT)) { 501 if (tls_config_set_protocols(tls_cfg, 502 TLS_PROTOCOLS_ALL) != 0) 503 errx(1, "%s", tls_config_error(tls_cfg)); 504 if (tls_config_set_ciphers(tls_cfg, 505 (TLSopt & TLS_ALL) ? "all" : "compat") != 0) 506 errx(1, "%s", tls_config_error(tls_cfg)); 507 } 508 if (!lflag && (TLSopt & TLS_CCERT)) 509 errx(1, "clientcert is only valid with -l"); 510 if (TLSopt & TLS_NONAME) 511 tls_config_insecure_noverifyname(tls_cfg); 512 if (TLSopt & TLS_NOVERIFY) { 513 if (tls_expecthash != NULL) 514 errx(1, "-H and -T noverify may not be used " 515 "together"); 516 tls_config_insecure_noverifycert(tls_cfg); 517 } 518 if (TLSopt & TLS_MUSTSTAPLE) 519 tls_config_ocsp_require_stapling(tls_cfg); 520 521 if (Pflag) { 522 if (pledge("stdio inet dns tty", NULL) == -1) 523 err(1, "pledge"); 524 } else if (pledge("stdio inet dns", NULL) == -1) 525 err(1, "pledge"); 526 } 527 if (lflag) { 528 struct tls *tls_cctx = NULL; 529 int connfd; 530 ret = 0; 531 532 if (family == AF_UNIX) { 533 if (uflag) 534 s = unix_bind(host, 0); 535 else 536 s = unix_listen(host); 537 } 538 539 if (usetls) { 540 tls_config_verify_client_optional(tls_cfg); 541 if ((tls_ctx = tls_server()) == NULL) 542 errx(1, "tls server creation failed"); 543 if (tls_configure(tls_ctx, tls_cfg) == -1) 544 errx(1, "tls configuration failed (%s)", 545 tls_error(tls_ctx)); 546 } 547 /* Allow only one connection at a time, but stay alive. */ 548 for (;;) { 549 if (family != AF_UNIX) 550 s = local_listen(host, uport, hints); 551 if (s < 0) 552 err(1, NULL); 553 if (uflag && kflag) { 554 /* 555 * For UDP and -k, don't connect the socket, 556 * let it receive datagrams from multiple 557 * socket pairs. 558 */ 559 readwrite(s, NULL); 560 } else if (uflag && !kflag) { 561 /* 562 * For UDP and not -k, we will use recvfrom() 563 * initially to wait for a caller, then use 564 * the regular functions to talk to the caller. 565 */ 566 int rv, plen; 567 char buf[16384]; 568 struct sockaddr_storage z; 569 570 len = sizeof(z); 571 plen = 2048; 572 rv = recvfrom(s, buf, plen, MSG_PEEK, 573 (struct sockaddr *)&z, &len); 574 if (rv < 0) 575 err(1, "recvfrom"); 576 577 rv = connect(s, (struct sockaddr *)&z, len); 578 if (rv < 0) 579 err(1, "connect"); 580 581 if (vflag) 582 report_connect((struct sockaddr *)&z, len, NULL); 583 584 readwrite(s, NULL); 585 } else { 586 len = sizeof(cliaddr); 587 connfd = accept4(s, (struct sockaddr *)&cliaddr, 588 &len, SOCK_NONBLOCK); 589 if (connfd == -1) { 590 /* For now, all errnos are fatal */ 591 err(1, "accept"); 592 } 593 if (vflag) 594 report_connect((struct sockaddr *)&cliaddr, len, 595 family == AF_UNIX ? host : NULL); 596 if ((usetls) && 597 (tls_cctx = tls_setup_server(tls_ctx, connfd, host))) 598 readwrite(connfd, tls_cctx); 599 if (!usetls) 600 readwrite(connfd, NULL); 601 if (tls_cctx) { 602 timeout_tls(s, tls_cctx, tls_close); 603 tls_free(tls_cctx); 604 tls_cctx = NULL; 605 } 606 close(connfd); 607 } 608 if (family != AF_UNIX) 609 close(s); 610 else if (uflag) { 611 if (connect(s, NULL, 0) < 0) 612 err(1, "connect"); 613 } 614 615 if (!kflag) 616 break; 617 } 618 } else if (family == AF_UNIX) { 619 ret = 0; 620 621 if ((s = unix_connect(host)) > 0) { 622 if (!zflag) 623 readwrite(s, NULL); 624 close(s); 625 } else 626 ret = 1; 627 628 if (uflag) 629 unlink(unix_dg_tmp_socket); 630 return ret; 631 632 } else { 633 int i = 0; 634 635 /* Construct the portlist[] array. */ 636 build_ports(uport); 637 638 /* Cycle through portlist, connecting to each port. */ 639 for (s = -1, i = 0; portlist[i] != NULL; i++) { 640 if (s != -1) 641 close(s); 642 643 if (usetls) { 644 if ((tls_ctx = tls_client()) == NULL) 645 errx(1, "tls client creation failed"); 646 if (tls_configure(tls_ctx, tls_cfg) == -1) 647 errx(1, "tls configuration failed (%s)", 648 tls_error(tls_ctx)); 649 } 650 if (xflag) 651 s = socks_connect(host, portlist[i], hints, 652 proxy, proxyport, proxyhints, socksv, 653 Pflag); 654 else 655 s = remote_connect(host, portlist[i], hints); 656 657 if (s == -1) 658 continue; 659 660 ret = 0; 661 if (vflag || zflag) { 662 /* For UDP, make sure we are connected. */ 663 if (uflag) { 664 if (udptest(s) == -1) { 665 ret = 1; 666 continue; 667 } 668 } 669 670 /* Don't look up port if -n. */ 671 if (nflag) 672 sv = NULL; 673 else { 674 sv = getservbyport( 675 ntohs(atoi(portlist[i])), 676 uflag ? "udp" : "tcp"); 677 } 678 679 fprintf(stderr, 680 "Connection to %s %s port [%s/%s] " 681 "succeeded!\n", host, portlist[i], 682 uflag ? "udp" : "tcp", 683 sv ? sv->s_name : "*"); 684 } 685 if (Fflag) 686 fdpass(s); 687 else { 688 if (usetls) 689 tls_setup_client(tls_ctx, s, host); 690 if (!zflag) 691 readwrite(s, tls_ctx); 692 if (tls_ctx) { 693 timeout_tls(s, tls_ctx, tls_close); 694 tls_free(tls_ctx); 695 tls_ctx = NULL; 696 } 697 } 698 } 699 } 700 701 if (s != -1) 702 close(s); 703 704 tls_config_free(tls_cfg); 705 706 return ret; 707 } 708 709 /* 710 * unix_bind() 711 * Returns a unix socket bound to the given path 712 */ 713 int 714 unix_bind(char *path, int flags) 715 { 716 struct sockaddr_un s_un; 717 int s, save_errno; 718 719 /* Create unix domain socket. */ 720 if ((s = socket(AF_UNIX, flags | (uflag ? SOCK_DGRAM : SOCK_STREAM), 721 0)) < 0) 722 return -1; 723 724 memset(&s_un, 0, sizeof(struct sockaddr_un)); 725 s_un.sun_family = AF_UNIX; 726 727 if (strlcpy(s_un.sun_path, path, sizeof(s_un.sun_path)) >= 728 sizeof(s_un.sun_path)) { 729 close(s); 730 errno = ENAMETOOLONG; 731 return -1; 732 } 733 734 if (bind(s, (struct sockaddr *)&s_un, sizeof(s_un)) < 0) { 735 save_errno = errno; 736 close(s); 737 errno = save_errno; 738 return -1; 739 } 740 741 return s; 742 } 743 744 int 745 timeout_tls(int s, struct tls *tls_ctx, int (*func)(struct tls *)) 746 { 747 struct pollfd pfd; 748 int ret; 749 750 while ((ret = (*func)(tls_ctx)) != 0) { 751 if (ret == TLS_WANT_POLLIN) 752 pfd.events = POLLIN; 753 else if (ret == TLS_WANT_POLLOUT) 754 pfd.events = POLLOUT; 755 else 756 break; 757 pfd.fd = s; 758 if ((ret = poll(&pfd, 1, timeout)) == 1) 759 continue; 760 else if (ret == 0) { 761 errno = ETIMEDOUT; 762 ret = -1; 763 break; 764 } else 765 err(1, "poll failed"); 766 } 767 768 return ret; 769 } 770 771 void 772 tls_setup_client(struct tls *tls_ctx, int s, char *host) 773 { 774 const char *errstr; 775 776 if (tls_connect_socket(tls_ctx, s, 777 tls_expectname ? tls_expectname : host) == -1) { 778 errx(1, "tls connection failed (%s)", 779 tls_error(tls_ctx)); 780 } 781 if (timeout_tls(s, tls_ctx, tls_handshake) == -1) { 782 if ((errstr = tls_error(tls_ctx)) == NULL) 783 errstr = strerror(errno); 784 errx(1, "tls handshake failed (%s)", errstr); 785 } 786 if (vflag) 787 report_tls(tls_ctx, host); 788 if (tls_expecthash && tls_peer_cert_hash(tls_ctx) && 789 strcmp(tls_expecthash, tls_peer_cert_hash(tls_ctx)) != 0) 790 errx(1, "peer certificate is not %s", tls_expecthash); 791 if (Zflag) { 792 save_peer_cert(tls_ctx, Zflag); 793 if (Zflag != stderr && (fclose(Zflag) != 0)) 794 err(1, "fclose failed saving peer cert"); 795 } 796 } 797 798 struct tls * 799 tls_setup_server(struct tls *tls_ctx, int connfd, char *host) 800 { 801 struct tls *tls_cctx; 802 const char *errstr; 803 804 if (tls_accept_socket(tls_ctx, &tls_cctx, connfd) == -1) { 805 warnx("tls accept failed (%s)", tls_error(tls_ctx)); 806 } else if (timeout_tls(connfd, tls_cctx, tls_handshake) == -1) { 807 if ((errstr = tls_error(tls_cctx)) == NULL) 808 errstr = strerror(errno); 809 warnx("tls handshake failed (%s)", errstr); 810 } else { 811 int gotcert = tls_peer_cert_provided(tls_cctx); 812 813 if (vflag && gotcert) 814 report_tls(tls_cctx, host); 815 if ((TLSopt & TLS_CCERT) && !gotcert) 816 warnx("No client certificate provided"); 817 else if (gotcert && tls_peer_cert_hash(tls_ctx) && tls_expecthash && 818 strcmp(tls_expecthash, tls_peer_cert_hash(tls_ctx)) != 0) 819 warnx("peer certificate is not %s", tls_expecthash); 820 else if (gotcert && tls_expectname && 821 (!tls_peer_cert_contains_name(tls_cctx, tls_expectname))) 822 warnx("name (%s) not found in client cert", 823 tls_expectname); 824 else { 825 return tls_cctx; 826 } 827 } 828 return NULL; 829 } 830 831 /* 832 * unix_connect() 833 * Returns a socket connected to a local unix socket. Returns -1 on failure. 834 */ 835 int 836 unix_connect(char *path) 837 { 838 struct sockaddr_un s_un; 839 int s, save_errno; 840 841 if (uflag) { 842 if ((s = unix_bind(unix_dg_tmp_socket, SOCK_CLOEXEC)) < 0) 843 return -1; 844 } else { 845 if ((s = socket(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC, 0)) < 0) 846 return -1; 847 } 848 849 memset(&s_un, 0, sizeof(struct sockaddr_un)); 850 s_un.sun_family = AF_UNIX; 851 852 if (strlcpy(s_un.sun_path, path, sizeof(s_un.sun_path)) >= 853 sizeof(s_un.sun_path)) { 854 close(s); 855 errno = ENAMETOOLONG; 856 return -1; 857 } 858 if (connect(s, (struct sockaddr *)&s_un, sizeof(s_un)) < 0) { 859 save_errno = errno; 860 close(s); 861 errno = save_errno; 862 return -1; 863 } 864 return s; 865 866 } 867 868 /* 869 * unix_listen() 870 * Create a unix domain socket, and listen on it. 871 */ 872 int 873 unix_listen(char *path) 874 { 875 int s; 876 if ((s = unix_bind(path, 0)) < 0) 877 return -1; 878 879 if (listen(s, 5) < 0) { 880 close(s); 881 return -1; 882 } 883 return s; 884 } 885 886 /* 887 * remote_connect() 888 * Returns a socket connected to a remote host. Properly binds to a local 889 * port or source address if needed. Returns -1 on failure. 890 */ 891 int 892 remote_connect(const char *host, const char *port, struct addrinfo hints) 893 { 894 struct addrinfo *res, *res0; 895 int s = -1, error, on = 1, save_errno; 896 897 if ((error = getaddrinfo(host, port, &hints, &res0))) 898 errx(1, "getaddrinfo for host \"%s\" port %s: %s", host, 899 port, gai_strerror(error)); 900 901 for (res = res0; res; res = res->ai_next) { 902 if ((s = socket(res->ai_family, res->ai_socktype | 903 SOCK_NONBLOCK, res->ai_protocol)) < 0) 904 continue; 905 906 /* Bind to a local port or source address if specified. */ 907 if (sflag || pflag) { 908 struct addrinfo ahints, *ares; 909 910 /* try SO_BINDANY, but don't insist */ 911 setsockopt(s, SOL_SOCKET, SO_BINDANY, &on, sizeof(on)); 912 memset(&ahints, 0, sizeof(struct addrinfo)); 913 ahints.ai_family = res->ai_family; 914 ahints.ai_socktype = uflag ? SOCK_DGRAM : SOCK_STREAM; 915 ahints.ai_protocol = uflag ? IPPROTO_UDP : IPPROTO_TCP; 916 ahints.ai_flags = AI_PASSIVE; 917 if ((error = getaddrinfo(sflag, pflag, &ahints, &ares))) 918 errx(1, "getaddrinfo: %s", gai_strerror(error)); 919 920 if (bind(s, (struct sockaddr *)ares->ai_addr, 921 ares->ai_addrlen) < 0) 922 err(1, "bind failed"); 923 freeaddrinfo(ares); 924 } 925 926 set_common_sockopts(s, res->ai_family); 927 928 if (timeout_connect(s, res->ai_addr, res->ai_addrlen) == 0) 929 break; 930 if (vflag) 931 warn("connect to %s port %s (%s) failed", host, port, 932 uflag ? "udp" : "tcp"); 933 934 save_errno = errno; 935 close(s); 936 errno = save_errno; 937 s = -1; 938 } 939 940 freeaddrinfo(res0); 941 942 return s; 943 } 944 945 int 946 timeout_connect(int s, const struct sockaddr *name, socklen_t namelen) 947 { 948 struct pollfd pfd; 949 socklen_t optlen; 950 int optval; 951 int ret; 952 953 if ((ret = connect(s, name, namelen)) != 0 && errno == EINPROGRESS) { 954 pfd.fd = s; 955 pfd.events = POLLOUT; 956 if ((ret = poll(&pfd, 1, timeout)) == 1) { 957 optlen = sizeof(optval); 958 if ((ret = getsockopt(s, SOL_SOCKET, SO_ERROR, 959 &optval, &optlen)) == 0) { 960 errno = optval; 961 ret = optval == 0 ? 0 : -1; 962 } 963 } else if (ret == 0) { 964 errno = ETIMEDOUT; 965 ret = -1; 966 } else 967 err(1, "poll failed"); 968 } 969 970 return ret; 971 } 972 973 /* 974 * local_listen() 975 * Returns a socket listening on a local port, binds to specified source 976 * address. Returns -1 on failure. 977 */ 978 int 979 local_listen(char *host, char *port, struct addrinfo hints) 980 { 981 struct addrinfo *res, *res0; 982 int s = -1, ret, x = 1, save_errno; 983 int error; 984 985 /* Allow nodename to be null. */ 986 hints.ai_flags |= AI_PASSIVE; 987 988 /* 989 * In the case of binding to a wildcard address 990 * default to binding to an ipv4 address. 991 */ 992 if (host == NULL && hints.ai_family == AF_UNSPEC) 993 hints.ai_family = AF_INET; 994 995 if ((error = getaddrinfo(host, port, &hints, &res0))) 996 errx(1, "getaddrinfo: %s", gai_strerror(error)); 997 998 for (res = res0; res; res = res->ai_next) { 999 if ((s = socket(res->ai_family, res->ai_socktype, 1000 res->ai_protocol)) < 0) 1001 continue; 1002 1003 ret = setsockopt(s, SOL_SOCKET, SO_REUSEPORT, &x, sizeof(x)); 1004 if (ret == -1) 1005 err(1, NULL); 1006 1007 set_common_sockopts(s, res->ai_family); 1008 1009 if (bind(s, (struct sockaddr *)res->ai_addr, 1010 res->ai_addrlen) == 0) 1011 break; 1012 1013 save_errno = errno; 1014 close(s); 1015 errno = save_errno; 1016 s = -1; 1017 } 1018 1019 if (!uflag && s != -1) { 1020 if (listen(s, 1) < 0) 1021 err(1, "listen"); 1022 } 1023 1024 freeaddrinfo(res0); 1025 1026 return s; 1027 } 1028 1029 /* 1030 * readwrite() 1031 * Loop that polls on the network file descriptor and stdin. 1032 */ 1033 void 1034 readwrite(int net_fd, struct tls *tls_ctx) 1035 { 1036 struct pollfd pfd[4]; 1037 int stdin_fd = STDIN_FILENO; 1038 int stdout_fd = STDOUT_FILENO; 1039 unsigned char netinbuf[BUFSIZE]; 1040 size_t netinbufpos = 0; 1041 unsigned char stdinbuf[BUFSIZE]; 1042 size_t stdinbufpos = 0; 1043 int n, num_fds; 1044 ssize_t ret; 1045 1046 /* don't read from stdin if requested */ 1047 if (dflag) 1048 stdin_fd = -1; 1049 1050 /* stdin */ 1051 pfd[POLL_STDIN].fd = stdin_fd; 1052 pfd[POLL_STDIN].events = POLLIN; 1053 1054 /* network out */ 1055 pfd[POLL_NETOUT].fd = net_fd; 1056 pfd[POLL_NETOUT].events = 0; 1057 1058 /* network in */ 1059 pfd[POLL_NETIN].fd = net_fd; 1060 pfd[POLL_NETIN].events = POLLIN; 1061 1062 /* stdout */ 1063 pfd[POLL_STDOUT].fd = stdout_fd; 1064 pfd[POLL_STDOUT].events = 0; 1065 1066 while (1) { 1067 /* both inputs are gone, buffers are empty, we are done */ 1068 if (pfd[POLL_STDIN].fd == -1 && pfd[POLL_NETIN].fd == -1 && 1069 stdinbufpos == 0 && netinbufpos == 0) 1070 return; 1071 /* both outputs are gone, we can't continue */ 1072 if (pfd[POLL_NETOUT].fd == -1 && pfd[POLL_STDOUT].fd == -1) 1073 return; 1074 /* listen and net in gone, queues empty, done */ 1075 if (lflag && pfd[POLL_NETIN].fd == -1 && 1076 stdinbufpos == 0 && netinbufpos == 0) 1077 return; 1078 1079 /* help says -i is for "wait between lines sent". We read and 1080 * write arbitrary amounts of data, and we don't want to start 1081 * scanning for newlines, so this is as good as it gets */ 1082 if (iflag) 1083 sleep(iflag); 1084 1085 /* poll */ 1086 num_fds = poll(pfd, 4, timeout); 1087 1088 /* treat poll errors */ 1089 if (num_fds == -1) 1090 err(1, "polling error"); 1091 1092 /* timeout happened */ 1093 if (num_fds == 0) 1094 return; 1095 1096 /* treat socket error conditions */ 1097 for (n = 0; n < 4; n++) { 1098 if (pfd[n].revents & (POLLERR|POLLNVAL)) { 1099 pfd[n].fd = -1; 1100 } 1101 } 1102 /* reading is possible after HUP */ 1103 if (pfd[POLL_STDIN].events & POLLIN && 1104 pfd[POLL_STDIN].revents & POLLHUP && 1105 !(pfd[POLL_STDIN].revents & POLLIN)) 1106 pfd[POLL_STDIN].fd = -1; 1107 1108 if (pfd[POLL_NETIN].events & POLLIN && 1109 pfd[POLL_NETIN].revents & POLLHUP && 1110 !(pfd[POLL_NETIN].revents & POLLIN)) 1111 pfd[POLL_NETIN].fd = -1; 1112 1113 if (pfd[POLL_NETOUT].revents & POLLHUP) { 1114 if (Nflag) 1115 shutdown(pfd[POLL_NETOUT].fd, SHUT_WR); 1116 pfd[POLL_NETOUT].fd = -1; 1117 } 1118 /* if HUP, stop watching stdout */ 1119 if (pfd[POLL_STDOUT].revents & POLLHUP) 1120 pfd[POLL_STDOUT].fd = -1; 1121 /* if no net out, stop watching stdin */ 1122 if (pfd[POLL_NETOUT].fd == -1) 1123 pfd[POLL_STDIN].fd = -1; 1124 /* if no stdout, stop watching net in */ 1125 if (pfd[POLL_STDOUT].fd == -1) { 1126 if (pfd[POLL_NETIN].fd != -1) 1127 shutdown(pfd[POLL_NETIN].fd, SHUT_RD); 1128 pfd[POLL_NETIN].fd = -1; 1129 } 1130 1131 /* try to read from stdin */ 1132 if (pfd[POLL_STDIN].revents & POLLIN && stdinbufpos < BUFSIZE) { 1133 ret = fillbuf(pfd[POLL_STDIN].fd, stdinbuf, 1134 &stdinbufpos, NULL); 1135 if (ret == TLS_WANT_POLLIN) 1136 pfd[POLL_STDIN].events = POLLIN; 1137 else if (ret == TLS_WANT_POLLOUT) 1138 pfd[POLL_STDIN].events = POLLOUT; 1139 else if (ret == 0 || ret == -1) 1140 pfd[POLL_STDIN].fd = -1; 1141 /* read something - poll net out */ 1142 if (stdinbufpos > 0) 1143 pfd[POLL_NETOUT].events = POLLOUT; 1144 /* filled buffer - remove self from polling */ 1145 if (stdinbufpos == BUFSIZE) 1146 pfd[POLL_STDIN].events = 0; 1147 } 1148 /* try to write to network */ 1149 if (pfd[POLL_NETOUT].revents & POLLOUT && stdinbufpos > 0) { 1150 ret = drainbuf(pfd[POLL_NETOUT].fd, stdinbuf, 1151 &stdinbufpos, tls_ctx); 1152 if (ret == TLS_WANT_POLLIN) 1153 pfd[POLL_NETOUT].events = POLLIN; 1154 else if (ret == TLS_WANT_POLLOUT) 1155 pfd[POLL_NETOUT].events = POLLOUT; 1156 else if (ret == -1) 1157 pfd[POLL_NETOUT].fd = -1; 1158 /* buffer empty - remove self from polling */ 1159 if (stdinbufpos == 0) 1160 pfd[POLL_NETOUT].events = 0; 1161 /* buffer no longer full - poll stdin again */ 1162 if (stdinbufpos < BUFSIZE) 1163 pfd[POLL_STDIN].events = POLLIN; 1164 } 1165 /* try to read from network */ 1166 if (pfd[POLL_NETIN].revents & POLLIN && netinbufpos < BUFSIZE) { 1167 ret = fillbuf(pfd[POLL_NETIN].fd, netinbuf, 1168 &netinbufpos, tls_ctx); 1169 if (ret == TLS_WANT_POLLIN) 1170 pfd[POLL_NETIN].events = POLLIN; 1171 else if (ret == TLS_WANT_POLLOUT) 1172 pfd[POLL_NETIN].events = POLLOUT; 1173 else if (ret == -1) 1174 pfd[POLL_NETIN].fd = -1; 1175 /* eof on net in - remove from pfd */ 1176 if (ret == 0) { 1177 shutdown(pfd[POLL_NETIN].fd, SHUT_RD); 1178 pfd[POLL_NETIN].fd = -1; 1179 } 1180 if (recvlimit > 0 && ++recvcount >= recvlimit) { 1181 if (pfd[POLL_NETIN].fd != -1) 1182 shutdown(pfd[POLL_NETIN].fd, SHUT_RD); 1183 pfd[POLL_NETIN].fd = -1; 1184 pfd[POLL_STDIN].fd = -1; 1185 } 1186 /* read something - poll stdout */ 1187 if (netinbufpos > 0) 1188 pfd[POLL_STDOUT].events = POLLOUT; 1189 /* filled buffer - remove self from polling */ 1190 if (netinbufpos == BUFSIZE) 1191 pfd[POLL_NETIN].events = 0; 1192 /* handle telnet */ 1193 if (tflag) 1194 atelnet(pfd[POLL_NETIN].fd, netinbuf, 1195 netinbufpos); 1196 } 1197 /* try to write to stdout */ 1198 if (pfd[POLL_STDOUT].revents & POLLOUT && netinbufpos > 0) { 1199 ret = drainbuf(pfd[POLL_STDOUT].fd, netinbuf, 1200 &netinbufpos, NULL); 1201 if (ret == TLS_WANT_POLLIN) 1202 pfd[POLL_STDOUT].events = POLLIN; 1203 else if (ret == TLS_WANT_POLLOUT) 1204 pfd[POLL_STDOUT].events = POLLOUT; 1205 else if (ret == -1) 1206 pfd[POLL_STDOUT].fd = -1; 1207 /* buffer empty - remove self from polling */ 1208 if (netinbufpos == 0) 1209 pfd[POLL_STDOUT].events = 0; 1210 /* buffer no longer full - poll net in again */ 1211 if (netinbufpos < BUFSIZE) 1212 pfd[POLL_NETIN].events = POLLIN; 1213 } 1214 1215 /* stdin gone and queue empty? */ 1216 if (pfd[POLL_STDIN].fd == -1 && stdinbufpos == 0) { 1217 if (pfd[POLL_NETOUT].fd != -1 && Nflag) 1218 shutdown(pfd[POLL_NETOUT].fd, SHUT_WR); 1219 pfd[POLL_NETOUT].fd = -1; 1220 } 1221 /* net in gone and queue empty? */ 1222 if (pfd[POLL_NETIN].fd == -1 && netinbufpos == 0) { 1223 pfd[POLL_STDOUT].fd = -1; 1224 } 1225 } 1226 } 1227 1228 ssize_t 1229 drainbuf(int fd, unsigned char *buf, size_t *bufpos, struct tls *tls) 1230 { 1231 ssize_t n; 1232 ssize_t adjust; 1233 1234 if (tls) 1235 n = tls_write(tls, buf, *bufpos); 1236 else { 1237 n = write(fd, buf, *bufpos); 1238 /* don't treat EAGAIN, EINTR as error */ 1239 if (n == -1 && (errno == EAGAIN || errno == EINTR)) 1240 n = TLS_WANT_POLLOUT; 1241 } 1242 if (n <= 0) 1243 return n; 1244 /* adjust buffer */ 1245 adjust = *bufpos - n; 1246 if (adjust > 0) 1247 memmove(buf, buf + n, adjust); 1248 *bufpos -= n; 1249 return n; 1250 } 1251 1252 ssize_t 1253 fillbuf(int fd, unsigned char *buf, size_t *bufpos, struct tls *tls) 1254 { 1255 size_t num = BUFSIZE - *bufpos; 1256 ssize_t n; 1257 1258 if (tls) 1259 n = tls_read(tls, buf + *bufpos, num); 1260 else { 1261 n = read(fd, buf + *bufpos, num); 1262 /* don't treat EAGAIN, EINTR as error */ 1263 if (n == -1 && (errno == EAGAIN || errno == EINTR)) 1264 n = TLS_WANT_POLLIN; 1265 } 1266 if (n <= 0) 1267 return n; 1268 *bufpos += n; 1269 return n; 1270 } 1271 1272 /* 1273 * fdpass() 1274 * Pass the connected file descriptor to stdout and exit. 1275 */ 1276 void 1277 fdpass(int nfd) 1278 { 1279 struct msghdr mh; 1280 union { 1281 struct cmsghdr hdr; 1282 char buf[CMSG_SPACE(sizeof(int))]; 1283 } cmsgbuf; 1284 struct cmsghdr *cmsg; 1285 struct iovec iov; 1286 char c = '\0'; 1287 ssize_t r; 1288 struct pollfd pfd; 1289 1290 /* Avoid obvious stupidity */ 1291 if (isatty(STDOUT_FILENO)) 1292 errx(1, "Cannot pass file descriptor to tty"); 1293 1294 bzero(&mh, sizeof(mh)); 1295 bzero(&cmsgbuf, sizeof(cmsgbuf)); 1296 bzero(&iov, sizeof(iov)); 1297 1298 mh.msg_control = (caddr_t)&cmsgbuf.buf; 1299 mh.msg_controllen = sizeof(cmsgbuf.buf); 1300 cmsg = CMSG_FIRSTHDR(&mh); 1301 cmsg->cmsg_len = CMSG_LEN(sizeof(int)); 1302 cmsg->cmsg_level = SOL_SOCKET; 1303 cmsg->cmsg_type = SCM_RIGHTS; 1304 *(int *)CMSG_DATA(cmsg) = nfd; 1305 1306 iov.iov_base = &c; 1307 iov.iov_len = 1; 1308 mh.msg_iov = &iov; 1309 mh.msg_iovlen = 1; 1310 1311 bzero(&pfd, sizeof(pfd)); 1312 pfd.fd = STDOUT_FILENO; 1313 pfd.events = POLLOUT; 1314 for (;;) { 1315 r = sendmsg(STDOUT_FILENO, &mh, 0); 1316 if (r == -1) { 1317 if (errno == EAGAIN || errno == EINTR) { 1318 if (poll(&pfd, 1, -1) == -1) 1319 err(1, "poll"); 1320 continue; 1321 } 1322 err(1, "sendmsg"); 1323 } else if (r != 1) 1324 errx(1, "sendmsg: unexpected return value %zd", r); 1325 else 1326 break; 1327 } 1328 exit(0); 1329 } 1330 1331 /* Deal with RFC 854 WILL/WONT DO/DONT negotiation. */ 1332 void 1333 atelnet(int nfd, unsigned char *buf, unsigned int size) 1334 { 1335 unsigned char *p, *end; 1336 unsigned char obuf[4]; 1337 1338 if (size < 3) 1339 return; 1340 end = buf + size - 2; 1341 1342 for (p = buf; p < end; p++) { 1343 if (*p != IAC) 1344 continue; 1345 1346 obuf[0] = IAC; 1347 p++; 1348 if ((*p == WILL) || (*p == WONT)) 1349 obuf[1] = DONT; 1350 else if ((*p == DO) || (*p == DONT)) 1351 obuf[1] = WONT; 1352 else 1353 continue; 1354 1355 p++; 1356 obuf[2] = *p; 1357 if (atomicio(vwrite, nfd, obuf, 3) != 3) 1358 warn("Write Error!"); 1359 } 1360 } 1361 1362 1363 int 1364 strtoport(char *portstr, int udp) 1365 { 1366 struct servent *entry; 1367 const char *errstr; 1368 char *proto; 1369 int port = -1; 1370 1371 proto = udp ? "udp" : "tcp"; 1372 1373 port = strtonum(portstr, 1, PORT_MAX, &errstr); 1374 if (errstr == NULL) 1375 return port; 1376 if (errno != EINVAL) 1377 errx(1, "port number %s: %s", errstr, portstr); 1378 if ((entry = getservbyname(portstr, proto)) == NULL) 1379 errx(1, "service \"%s\" unknown", portstr); 1380 return ntohs(entry->s_port); 1381 } 1382 1383 /* 1384 * build_ports() 1385 * Build an array of ports in portlist[], listing each port 1386 * that we should try to connect to. 1387 */ 1388 void 1389 build_ports(char *p) 1390 { 1391 char *n; 1392 int hi, lo, cp; 1393 int x = 0; 1394 1395 if ((n = strchr(p, '-')) != NULL) { 1396 *n = '\0'; 1397 n++; 1398 1399 /* Make sure the ports are in order: lowest->highest. */ 1400 hi = strtoport(n, uflag); 1401 lo = strtoport(p, uflag); 1402 if (lo > hi) { 1403 cp = hi; 1404 hi = lo; 1405 lo = cp; 1406 } 1407 1408 /* 1409 * Initialize portlist with a random permutation. Based on 1410 * Knuth, as in ip_randomid() in sys/netinet/ip_id.c. 1411 */ 1412 if (rflag) { 1413 for (x = 0; x <= hi - lo; x++) { 1414 cp = arc4random_uniform(x + 1); 1415 portlist[x] = portlist[cp]; 1416 if (asprintf(&portlist[cp], "%d", x + lo) < 0) 1417 err(1, "asprintf"); 1418 } 1419 } else { /* Load ports sequentially. */ 1420 for (cp = lo; cp <= hi; cp++) { 1421 if (asprintf(&portlist[x], "%d", cp) < 0) 1422 err(1, "asprintf"); 1423 x++; 1424 } 1425 } 1426 } else { 1427 char *tmp; 1428 1429 hi = strtoport(p, uflag); 1430 if (asprintf(&tmp, "%d", hi) != -1) 1431 portlist[0] = tmp; 1432 else 1433 err(1, NULL); 1434 } 1435 } 1436 1437 /* 1438 * udptest() 1439 * Do a few writes to see if the UDP port is there. 1440 * Fails once PF state table is full. 1441 */ 1442 int 1443 udptest(int s) 1444 { 1445 int i, ret; 1446 1447 for (i = 0; i <= 3; i++) { 1448 if (write(s, "X", 1) == 1) 1449 ret = 1; 1450 else 1451 ret = -1; 1452 } 1453 return ret; 1454 } 1455 1456 void 1457 set_common_sockopts(int s, int af) 1458 { 1459 int x = 1; 1460 1461 if (Sflag) { 1462 if (setsockopt(s, IPPROTO_TCP, TCP_MD5SIG, 1463 &x, sizeof(x)) == -1) 1464 err(1, NULL); 1465 } 1466 if (Dflag) { 1467 if (setsockopt(s, SOL_SOCKET, SO_DEBUG, 1468 &x, sizeof(x)) == -1) 1469 err(1, NULL); 1470 } 1471 if (Tflag != -1) { 1472 if (af == AF_INET && setsockopt(s, IPPROTO_IP, 1473 IP_TOS, &Tflag, sizeof(Tflag)) == -1) 1474 err(1, "set IP ToS"); 1475 1476 else if (af == AF_INET6 && setsockopt(s, IPPROTO_IPV6, 1477 IPV6_TCLASS, &Tflag, sizeof(Tflag)) == -1) 1478 err(1, "set IPv6 traffic class"); 1479 } 1480 if (Iflag) { 1481 if (setsockopt(s, SOL_SOCKET, SO_RCVBUF, 1482 &Iflag, sizeof(Iflag)) == -1) 1483 err(1, "set TCP receive buffer size"); 1484 } 1485 if (Oflag) { 1486 if (setsockopt(s, SOL_SOCKET, SO_SNDBUF, 1487 &Oflag, sizeof(Oflag)) == -1) 1488 err(1, "set TCP send buffer size"); 1489 } 1490 1491 if (ttl != -1) { 1492 if (af == AF_INET && setsockopt(s, IPPROTO_IP, 1493 IP_TTL, &ttl, sizeof(ttl))) 1494 err(1, "set IP TTL"); 1495 1496 else if (af == AF_INET6 && setsockopt(s, IPPROTO_IPV6, 1497 IPV6_UNICAST_HOPS, &ttl, sizeof(ttl))) 1498 err(1, "set IPv6 unicast hops"); 1499 } 1500 1501 if (minttl != -1) { 1502 if (af == AF_INET && setsockopt(s, IPPROTO_IP, 1503 IP_MINTTL, &minttl, sizeof(minttl))) 1504 err(1, "set IP min TTL"); 1505 1506 else if (af == AF_INET6 && setsockopt(s, IPPROTO_IPV6, 1507 IPV6_MINHOPCOUNT, &minttl, sizeof(minttl))) 1508 err(1, "set IPv6 min hop count"); 1509 } 1510 } 1511 1512 int 1513 map_tos(char *s, int *val) 1514 { 1515 /* DiffServ Codepoints and other TOS mappings */ 1516 const struct toskeywords { 1517 const char *keyword; 1518 int val; 1519 } *t, toskeywords[] = { 1520 { "af11", IPTOS_DSCP_AF11 }, 1521 { "af12", IPTOS_DSCP_AF12 }, 1522 { "af13", IPTOS_DSCP_AF13 }, 1523 { "af21", IPTOS_DSCP_AF21 }, 1524 { "af22", IPTOS_DSCP_AF22 }, 1525 { "af23", IPTOS_DSCP_AF23 }, 1526 { "af31", IPTOS_DSCP_AF31 }, 1527 { "af32", IPTOS_DSCP_AF32 }, 1528 { "af33", IPTOS_DSCP_AF33 }, 1529 { "af41", IPTOS_DSCP_AF41 }, 1530 { "af42", IPTOS_DSCP_AF42 }, 1531 { "af43", IPTOS_DSCP_AF43 }, 1532 { "critical", IPTOS_PREC_CRITIC_ECP }, 1533 { "cs0", IPTOS_DSCP_CS0 }, 1534 { "cs1", IPTOS_DSCP_CS1 }, 1535 { "cs2", IPTOS_DSCP_CS2 }, 1536 { "cs3", IPTOS_DSCP_CS3 }, 1537 { "cs4", IPTOS_DSCP_CS4 }, 1538 { "cs5", IPTOS_DSCP_CS5 }, 1539 { "cs6", IPTOS_DSCP_CS6 }, 1540 { "cs7", IPTOS_DSCP_CS7 }, 1541 { "ef", IPTOS_DSCP_EF }, 1542 { "inetcontrol", IPTOS_PREC_INTERNETCONTROL }, 1543 { "lowdelay", IPTOS_LOWDELAY }, 1544 { "netcontrol", IPTOS_PREC_NETCONTROL }, 1545 { "reliability", IPTOS_RELIABILITY }, 1546 { "throughput", IPTOS_THROUGHPUT }, 1547 { NULL, -1 }, 1548 }; 1549 1550 for (t = toskeywords; t->keyword != NULL; t++) { 1551 if (strcmp(s, t->keyword) == 0) { 1552 *val = t->val; 1553 return 1; 1554 } 1555 } 1556 1557 return 0; 1558 } 1559 1560 int 1561 map_tls(char *s, int *val) 1562 { 1563 const struct tlskeywords { 1564 const char *keyword; 1565 int val; 1566 } *t, tlskeywords[] = { 1567 { "tlsall", TLS_ALL }, 1568 { "noverify", TLS_NOVERIFY }, 1569 { "noname", TLS_NONAME }, 1570 { "clientcert", TLS_CCERT}, 1571 { "muststaple", TLS_MUSTSTAPLE}, 1572 { "tlscompat", TLS_COMPAT }, 1573 { NULL, -1 }, 1574 }; 1575 1576 for (t = tlskeywords; t->keyword != NULL; t++) { 1577 if (strcmp(s, t->keyword) == 0) { 1578 *val |= t->val; 1579 return 1; 1580 } 1581 } 1582 return 0; 1583 } 1584 1585 void 1586 save_peer_cert(struct tls *tls_ctx, FILE *fp) 1587 { 1588 const char *pem; 1589 size_t plen; 1590 1591 if ((pem = tls_peer_cert_chain_pem(tls_ctx, &plen)) == NULL) 1592 errx(1, "Can't get peer certificate"); 1593 if (fprintf(fp, "%.*s", (int)plen, pem) < 0) 1594 err(1, "unable to save peer cert"); 1595 if (fflush(fp) != 0) 1596 err(1, "unable to flush peer cert"); 1597 } 1598 1599 void 1600 report_tls(struct tls * tls_ctx, char * host) 1601 { 1602 time_t t; 1603 const char *ocsp_url; 1604 1605 fprintf(stderr, "TLS handshake negotiated %s/%s with host %s\n", 1606 tls_conn_version(tls_ctx), tls_conn_cipher(tls_ctx), host); 1607 fprintf(stderr, "Peer name: %s\n", 1608 tls_expectname ? tls_expectname : host); 1609 if (tls_peer_cert_subject(tls_ctx)) 1610 fprintf(stderr, "Subject: %s\n", 1611 tls_peer_cert_subject(tls_ctx)); 1612 if (tls_peer_cert_issuer(tls_ctx)) 1613 fprintf(stderr, "Issuer: %s\n", 1614 tls_peer_cert_issuer(tls_ctx)); 1615 if ((t = tls_peer_cert_notbefore(tls_ctx)) != -1) 1616 fprintf(stderr, "Valid From: %s", ctime(&t)); 1617 if ((t = tls_peer_cert_notafter(tls_ctx)) != -1) 1618 fprintf(stderr, "Valid Until: %s", ctime(&t)); 1619 if (tls_peer_cert_hash(tls_ctx)) 1620 fprintf(stderr, "Cert Hash: %s\n", 1621 tls_peer_cert_hash(tls_ctx)); 1622 ocsp_url = tls_peer_ocsp_url(tls_ctx); 1623 if (ocsp_url != NULL) 1624 fprintf(stderr, "OCSP URL: %s\n", ocsp_url); 1625 switch (tls_peer_ocsp_response_status(tls_ctx)) { 1626 case TLS_OCSP_RESPONSE_SUCCESSFUL: 1627 fprintf(stderr, "OCSP Stapling: %s\n", 1628 tls_peer_ocsp_result(tls_ctx) == NULL ? "" : 1629 tls_peer_ocsp_result(tls_ctx)); 1630 fprintf(stderr, 1631 " response_status=%d cert_status=%d crl_reason=%d\n", 1632 tls_peer_ocsp_response_status(tls_ctx), 1633 tls_peer_ocsp_cert_status(tls_ctx), 1634 tls_peer_ocsp_crl_reason(tls_ctx)); 1635 t = tls_peer_ocsp_this_update(tls_ctx); 1636 fprintf(stderr, " this update: %s", 1637 t != -1 ? ctime(&t) : "\n"); 1638 t = tls_peer_ocsp_next_update(tls_ctx); 1639 fprintf(stderr, " next update: %s", 1640 t != -1 ? ctime(&t) : "\n"); 1641 t = tls_peer_ocsp_revocation_time(tls_ctx); 1642 fprintf(stderr, " revocation: %s", 1643 t != -1 ? ctime(&t) : "\n"); 1644 break; 1645 case -1: 1646 break; 1647 default: 1648 fprintf(stderr, "OCSP Stapling: failure - response_status %d (%s)\n", 1649 tls_peer_ocsp_response_status(tls_ctx), 1650 tls_peer_ocsp_result(tls_ctx) == NULL ? "" : 1651 tls_peer_ocsp_result(tls_ctx)); 1652 break; 1653 1654 } 1655 } 1656 1657 void 1658 report_connect(const struct sockaddr *sa, socklen_t salen, char *path) 1659 { 1660 char remote_host[NI_MAXHOST]; 1661 char remote_port[NI_MAXSERV]; 1662 int herr; 1663 int flags = NI_NUMERICSERV; 1664 1665 if (path != NULL) { 1666 fprintf(stderr, "Connection on %s received!\n", path); 1667 return; 1668 } 1669 1670 if (nflag) 1671 flags |= NI_NUMERICHOST; 1672 1673 if ((herr = getnameinfo(sa, salen, 1674 remote_host, sizeof(remote_host), 1675 remote_port, sizeof(remote_port), 1676 flags)) != 0) { 1677 if (herr == EAI_SYSTEM) 1678 err(1, "getnameinfo"); 1679 else 1680 errx(1, "getnameinfo: %s", gai_strerror(herr)); 1681 } 1682 1683 fprintf(stderr, 1684 "Connection from %s %s " 1685 "received!\n", remote_host, remote_port); 1686 } 1687 1688 void 1689 help(void) 1690 { 1691 usage(0); 1692 fprintf(stderr, "\tCommand Summary:\n\ 1693 \t-4 Use IPv4\n\ 1694 \t-6 Use IPv6\n\ 1695 \t-C certfile Public key file\n\ 1696 \t-c Use TLS\n\ 1697 \t-D Enable the debug socket option\n\ 1698 \t-d Detach from stdin\n\ 1699 \t-e name\t Required name in peer certificate\n\ 1700 \t-F Pass socket fd\n\ 1701 \t-H hash\t Hash string of peer certificate\n\ 1702 \t-h This help text\n\ 1703 \t-I length TCP receive buffer length\n\ 1704 \t-i interval Delay interval for lines sent, ports scanned\n\ 1705 \t-K keyfile Private key file\n\ 1706 \t-k Keep inbound sockets open for multiple connects\n\ 1707 \t-l Listen mode, for inbound connects\n\ 1708 \t-M ttl Outgoing TTL / Hop Limit\n\ 1709 \t-m minttl Minimum incoming TTL / Hop Limit\n\ 1710 \t-N Shutdown the network socket after EOF on stdin\n\ 1711 \t-n Suppress name/port resolutions\n\ 1712 \t-O length TCP send buffer length\n\ 1713 \t-o staplefile Staple file\n\ 1714 \t-P proxyuser\tUsername for proxy authentication\n\ 1715 \t-p port\t Specify local port for remote connects\n\ 1716 \t-R CAfile CA bundle\n\ 1717 \t-r Randomize remote ports\n\ 1718 \t-S Enable the TCP MD5 signature option\n\ 1719 \t-s source Local source address\n\ 1720 \t-T keyword TOS value or TLS options\n\ 1721 \t-t Answer TELNET negotiation\n\ 1722 \t-U Use UNIX domain socket\n\ 1723 \t-u UDP mode\n\ 1724 \t-V rtable Specify alternate routing table\n\ 1725 \t-v Verbose\n\ 1726 \t-W recvlimit Terminate after receiving a number of packets\n\ 1727 \t-w timeout Timeout for connects and final net reads\n\ 1728 \t-X proto Proxy protocol: \"4\", \"5\" (SOCKS) or \"connect\"\n\ 1729 \t-x addr[:port]\tSpecify proxy address and port\n\ 1730 \t-Z Peer certificate file\n\ 1731 \t-z Zero-I/O mode [used for scanning]\n\ 1732 Port numbers can be individual or ranges: lo-hi [inclusive]\n"); 1733 exit(1); 1734 } 1735 1736 void 1737 usage(int ret) 1738 { 1739 fprintf(stderr, 1740 "usage: nc [-46cDdFhklNnrStUuvz] [-C certfile] [-e name] " 1741 "[-H hash] [-I length]\n" 1742 "\t [-i interval] [-K keyfile] [-M ttl] [-m minttl] [-O length]\n" 1743 "\t [-o staplefile] [-P proxy_username] [-p source_port] " 1744 "[-R CAfile]\n" 1745 "\t [-s source] [-T keyword] [-V rtable] [-W recvlimit] " 1746 "[-w timeout]\n" 1747 "\t [-X proxy_protocol] [-x proxy_address[:port]] " 1748 "[-Z peercertfile]\n" 1749 "\t [destination] [port]\n"); 1750 if (ret) 1751 exit(1); 1752 } 1753