1 /* $OpenBSD: netcat.c,v 1.217 2020/02/12 14:46:36 schwarze 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 #define PORT_MAX 65535 63 #define UNIX_DG_TMP_SOCKET_SIZE 19 64 65 #define POLL_STDIN 0 66 #define POLL_NETOUT 1 67 #define POLL_NETIN 2 68 #define POLL_STDOUT 3 69 #define BUFSIZE 16384 70 71 #define TLS_NOVERIFY (1 << 1) 72 #define TLS_NONAME (1 << 2) 73 #define TLS_CCERT (1 << 3) 74 #define TLS_MUSTSTAPLE (1 << 4) 75 76 /* Command Line Options */ 77 int dflag; /* detached, no stdin */ 78 int Fflag; /* fdpass sock to stdout */ 79 unsigned int iflag; /* Interval Flag */ 80 int kflag; /* More than one connect */ 81 int lflag; /* Bind to local port */ 82 int Nflag; /* shutdown() network socket */ 83 int nflag; /* Don't do name look up */ 84 char *Pflag; /* Proxy username */ 85 char *pflag; /* Localport flag */ 86 int rflag; /* Random ports flag */ 87 char *sflag; /* Source Address */ 88 int tflag; /* Telnet Emulation */ 89 int uflag; /* UDP - Default to TCP */ 90 int vflag; /* Verbosity */ 91 int xflag; /* Socks proxy */ 92 int zflag; /* Port Scan Flag */ 93 int Dflag; /* sodebug */ 94 int Iflag; /* TCP receive buffer size */ 95 int Oflag; /* TCP send buffer size */ 96 int Sflag; /* TCP MD5 signature option */ 97 int Tflag = -1; /* IP Type of Service */ 98 int rtableid = -1; 99 100 int usetls; /* use TLS */ 101 const char *Cflag; /* Public cert file */ 102 const char *Kflag; /* Private key file */ 103 const char *oflag; /* OCSP stapling file */ 104 const char *Rflag; /* Root CA file */ 105 int tls_cachanged; /* Using non-default CA file */ 106 int TLSopt; /* TLS options */ 107 char *tls_expectname; /* required name in peer cert */ 108 char *tls_expecthash; /* required hash of peer cert */ 109 char *tls_ciphers; /* TLS ciphers */ 110 char *tls_protocols; /* TLS protocols */ 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(const char *, const 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, char *); 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 process_tos_opt(char *, int *); 139 int process_tls_opt(char *, int *); 140 void save_peer_cert(struct tls *_tls_ctx, FILE *_fp); 141 void report_sock(const char *, 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 char ipaddr[NI_MAXHOST]; 155 struct addrinfo hints; 156 struct servent *sv; 157 socklen_t len; 158 struct sockaddr_storage cliaddr; 159 char *proxy = NULL, *proxyport = NULL; 160 const char *errstr; 161 struct addrinfo proxyhints; 162 char unix_dg_tmp_socket_buf[UNIX_DG_TMP_SOCKET_SIZE]; 163 struct tls_config *tls_cfg = NULL; 164 struct tls *tls_ctx = NULL; 165 uint32_t protocols; 166 167 ret = 1; 168 socksv = 5; 169 host = NULL; 170 uport = NULL; 171 sv = NULL; 172 Rflag = tls_default_ca_cert_file(); 173 174 signal(SIGPIPE, SIG_IGN); 175 176 while ((ch = getopt(argc, argv, 177 "46C:cDde:FH:hI:i:K:klM:m:NnO:o:P:p:R:rSs:T:tUuV:vW:w:X:x:Z:z")) 178 != -1) { 179 switch (ch) { 180 case '4': 181 family = AF_INET; 182 break; 183 case '6': 184 family = AF_INET6; 185 break; 186 case 'U': 187 family = AF_UNIX; 188 break; 189 case 'X': 190 if (strcasecmp(optarg, "connect") == 0) 191 socksv = -1; /* HTTP proxy CONNECT */ 192 else if (strcmp(optarg, "4") == 0) 193 socksv = 4; /* SOCKS v.4 */ 194 else if (strcmp(optarg, "5") == 0) 195 socksv = 5; /* SOCKS v.5 */ 196 else 197 errx(1, "unsupported proxy protocol"); 198 break; 199 case 'C': 200 Cflag = optarg; 201 break; 202 case 'c': 203 usetls = 1; 204 break; 205 case 'd': 206 dflag = 1; 207 break; 208 case 'e': 209 tls_expectname = optarg; 210 break; 211 case 'F': 212 Fflag = 1; 213 break; 214 case 'H': 215 tls_expecthash = optarg; 216 break; 217 case 'h': 218 help(); 219 break; 220 case 'i': 221 iflag = strtonum(optarg, 0, UINT_MAX, &errstr); 222 if (errstr) 223 errx(1, "interval %s: %s", errstr, optarg); 224 break; 225 case 'K': 226 Kflag = optarg; 227 break; 228 case 'k': 229 kflag = 1; 230 break; 231 case 'l': 232 lflag = 1; 233 break; 234 case 'M': 235 ttl = strtonum(optarg, 0, 255, &errstr); 236 if (errstr) 237 errx(1, "ttl is %s", errstr); 238 break; 239 case 'm': 240 minttl = strtonum(optarg, 0, 255, &errstr); 241 if (errstr) 242 errx(1, "minttl is %s", errstr); 243 break; 244 case 'N': 245 Nflag = 1; 246 break; 247 case 'n': 248 nflag = 1; 249 break; 250 case 'P': 251 Pflag = optarg; 252 break; 253 case 'p': 254 pflag = optarg; 255 break; 256 case 'R': 257 tls_cachanged = 1; 258 Rflag = optarg; 259 break; 260 case 'r': 261 rflag = 1; 262 break; 263 case 's': 264 sflag = optarg; 265 break; 266 case 't': 267 tflag = 1; 268 break; 269 case 'u': 270 uflag = 1; 271 break; 272 case 'V': 273 rtableid = (int)strtonum(optarg, 0, 274 RT_TABLEID_MAX, &errstr); 275 if (errstr) 276 errx(1, "rtable %s: %s", errstr, optarg); 277 break; 278 case 'v': 279 vflag = 1; 280 break; 281 case 'W': 282 recvlimit = strtonum(optarg, 1, INT_MAX, &errstr); 283 if (errstr) 284 errx(1, "receive limit %s: %s", errstr, optarg); 285 break; 286 case 'w': 287 timeout = strtonum(optarg, 0, INT_MAX / 1000, &errstr); 288 if (errstr) 289 errx(1, "timeout %s: %s", errstr, optarg); 290 timeout *= 1000; 291 break; 292 case 'x': 293 xflag = 1; 294 if ((proxy = strdup(optarg)) == NULL) 295 err(1, NULL); 296 break; 297 case 'Z': 298 if (strcmp(optarg, "-") == 0) 299 Zflag = stderr; 300 else if ((Zflag = fopen(optarg, "w")) == NULL) 301 err(1, "can't open %s", optarg); 302 break; 303 case 'z': 304 zflag = 1; 305 break; 306 case 'D': 307 Dflag = 1; 308 break; 309 case 'I': 310 Iflag = strtonum(optarg, 1, 65536 << 14, &errstr); 311 if (errstr != NULL) 312 errx(1, "TCP receive window %s: %s", 313 errstr, optarg); 314 break; 315 case 'O': 316 Oflag = strtonum(optarg, 1, 65536 << 14, &errstr); 317 if (errstr != NULL) 318 errx(1, "TCP send window %s: %s", 319 errstr, optarg); 320 break; 321 case 'o': 322 oflag = optarg; 323 break; 324 case 'S': 325 Sflag = 1; 326 break; 327 case 'T': 328 errstr = NULL; 329 errno = 0; 330 if (process_tls_opt(optarg, &TLSopt)) 331 break; 332 if (process_tos_opt(optarg, &Tflag)) 333 break; 334 if (strlen(optarg) > 1 && optarg[0] == '0' && 335 optarg[1] == 'x') 336 Tflag = (int)strtol(optarg, NULL, 16); 337 else 338 Tflag = (int)strtonum(optarg, 0, 255, 339 &errstr); 340 if (Tflag < 0 || Tflag > 255 || errstr || errno) 341 errx(1, "illegal tos/tls value %s", optarg); 342 break; 343 default: 344 usage(1); 345 } 346 } 347 argc -= optind; 348 argv += optind; 349 350 if (rtableid >= 0) 351 if (setrtable(rtableid) == -1) 352 err(1, "setrtable"); 353 354 /* Cruft to make sure options are clean, and used properly. */ 355 if (argc == 1 && family == AF_UNIX) { 356 host = argv[0]; 357 } else if (argc == 1 && lflag) { 358 uport = argv[0]; 359 } else if (argc == 2) { 360 host = argv[0]; 361 uport = argv[1]; 362 } else 363 usage(1); 364 365 if (usetls) { 366 if (Cflag && unveil(Cflag, "r") == -1) 367 err(1, "unveil"); 368 if (unveil(Rflag, "r") == -1) 369 err(1, "unveil"); 370 if (Kflag && unveil(Kflag, "r") == -1) 371 err(1, "unveil"); 372 if (oflag && unveil(oflag, "r") == -1) 373 err(1, "unveil"); 374 } else if (family == AF_UNIX && uflag && lflag && !kflag) { 375 /* 376 * After recvfrom(2) from client, the server connects 377 * to the client socket. As the client path is determined 378 * during runtime, we cannot unveil(2). 379 */ 380 } else { 381 if (family == AF_UNIX) { 382 if (unveil(host, "rwc") == -1) 383 err(1, "unveil"); 384 if (uflag && !kflag) { 385 if (sflag) { 386 if (unveil(sflag, "rwc") == -1) 387 err(1, "unveil"); 388 } else { 389 if (unveil("/tmp", "rwc") == -1) 390 err(1, "unveil"); 391 } 392 } 393 } else { 394 /* no filesystem visibility */ 395 if (unveil("/", "") == -1) 396 err(1, "unveil"); 397 } 398 } 399 400 if (family == AF_UNIX) { 401 if (pledge("stdio rpath wpath cpath tmppath unix", NULL) == -1) 402 err(1, "pledge"); 403 } else if (Fflag && Pflag) { 404 if (pledge("stdio inet dns sendfd tty", NULL) == -1) 405 err(1, "pledge"); 406 } else if (Fflag) { 407 if (pledge("stdio inet dns sendfd", NULL) == -1) 408 err(1, "pledge"); 409 } else if (Pflag && usetls) { 410 if (pledge("stdio rpath inet dns tty", NULL) == -1) 411 err(1, "pledge"); 412 } else if (Pflag) { 413 if (pledge("stdio inet dns tty", NULL) == -1) 414 err(1, "pledge"); 415 } else if (usetls) { 416 if (pledge("stdio rpath inet dns", NULL) == -1) 417 err(1, "pledge"); 418 } else if (pledge("stdio inet dns", NULL) == -1) 419 err(1, "pledge"); 420 421 if (lflag && sflag) 422 errx(1, "cannot use -s and -l"); 423 if (lflag && pflag) 424 errx(1, "cannot use -p and -l"); 425 if (lflag && zflag) 426 errx(1, "cannot use -z and -l"); 427 if (!lflag && kflag) 428 errx(1, "must use -l with -k"); 429 if (uflag && usetls) 430 errx(1, "cannot use -c and -u"); 431 if ((family == AF_UNIX) && usetls) 432 errx(1, "cannot use -c and -U"); 433 if ((family == AF_UNIX) && Fflag) 434 errx(1, "cannot use -F and -U"); 435 if (Fflag && usetls) 436 errx(1, "cannot use -c and -F"); 437 if (TLSopt && !usetls) 438 errx(1, "you must specify -c to use TLS options"); 439 if (Cflag && !usetls) 440 errx(1, "you must specify -c to use -C"); 441 if (Kflag && !usetls) 442 errx(1, "you must specify -c to use -K"); 443 if (Zflag && !usetls) 444 errx(1, "you must specify -c to use -Z"); 445 if (oflag && !Cflag) 446 errx(1, "you must specify -C to use -o"); 447 if (tls_cachanged && !usetls) 448 errx(1, "you must specify -c to use -R"); 449 if (tls_expecthash && !usetls) 450 errx(1, "you must specify -c to use -H"); 451 if (tls_expectname && !usetls) 452 errx(1, "you must specify -c to use -e"); 453 454 /* Get name of temporary socket for unix datagram client */ 455 if ((family == AF_UNIX) && uflag && !lflag) { 456 if (sflag) { 457 unix_dg_tmp_socket = sflag; 458 } else { 459 strlcpy(unix_dg_tmp_socket_buf, "/tmp/nc.XXXXXXXXXX", 460 UNIX_DG_TMP_SOCKET_SIZE); 461 if (mktemp(unix_dg_tmp_socket_buf) == NULL) 462 err(1, "mktemp"); 463 unix_dg_tmp_socket = unix_dg_tmp_socket_buf; 464 } 465 } 466 467 /* Initialize addrinfo structure. */ 468 if (family != AF_UNIX) { 469 memset(&hints, 0, sizeof(struct addrinfo)); 470 hints.ai_family = family; 471 hints.ai_socktype = uflag ? SOCK_DGRAM : SOCK_STREAM; 472 hints.ai_protocol = uflag ? IPPROTO_UDP : IPPROTO_TCP; 473 if (nflag) 474 hints.ai_flags |= AI_NUMERICHOST; 475 } 476 477 if (xflag) { 478 if (uflag) 479 errx(1, "no proxy support for UDP mode"); 480 481 if (lflag) 482 errx(1, "no proxy support for listen"); 483 484 if (family == AF_UNIX) 485 errx(1, "no proxy support for unix sockets"); 486 487 if (sflag) 488 errx(1, "no proxy support for local source address"); 489 490 if (*proxy == '[') { 491 ++proxy; 492 proxyport = strchr(proxy, ']'); 493 if (proxyport == NULL) 494 errx(1, "missing closing bracket in proxy"); 495 *proxyport++ = '\0'; 496 if (*proxyport == '\0') 497 /* Use default proxy port. */ 498 proxyport = NULL; 499 else { 500 if (*proxyport == ':') 501 ++proxyport; 502 else 503 errx(1, "garbage proxy port delimiter"); 504 } 505 } else { 506 proxyport = strrchr(proxy, ':'); 507 if (proxyport != NULL) 508 *proxyport++ = '\0'; 509 } 510 511 memset(&proxyhints, 0, sizeof(struct addrinfo)); 512 proxyhints.ai_family = family; 513 proxyhints.ai_socktype = SOCK_STREAM; 514 proxyhints.ai_protocol = IPPROTO_TCP; 515 if (nflag) 516 proxyhints.ai_flags |= AI_NUMERICHOST; 517 } 518 519 if (usetls) { 520 if ((tls_cfg = tls_config_new()) == NULL) 521 errx(1, "unable to allocate TLS config"); 522 if (Rflag && tls_config_set_ca_file(tls_cfg, Rflag) == -1) 523 errx(1, "%s", tls_config_error(tls_cfg)); 524 if (Cflag && tls_config_set_cert_file(tls_cfg, Cflag) == -1) 525 errx(1, "%s", tls_config_error(tls_cfg)); 526 if (Kflag && tls_config_set_key_file(tls_cfg, Kflag) == -1) 527 errx(1, "%s", tls_config_error(tls_cfg)); 528 if (oflag && tls_config_set_ocsp_staple_file(tls_cfg, oflag) == -1) 529 errx(1, "%s", tls_config_error(tls_cfg)); 530 if (tls_config_parse_protocols(&protocols, tls_protocols) == -1) 531 errx(1, "invalid TLS protocols `%s'", tls_protocols); 532 if (tls_config_set_protocols(tls_cfg, protocols) == -1) 533 errx(1, "%s", tls_config_error(tls_cfg)); 534 if (tls_config_set_ciphers(tls_cfg, tls_ciphers) == -1) 535 errx(1, "%s", tls_config_error(tls_cfg)); 536 if (!lflag && (TLSopt & TLS_CCERT)) 537 errx(1, "clientcert is only valid with -l"); 538 if (TLSopt & TLS_NONAME) 539 tls_config_insecure_noverifyname(tls_cfg); 540 if (TLSopt & TLS_NOVERIFY) { 541 if (tls_expecthash != NULL) 542 errx(1, "-H and -T noverify may not be used " 543 "together"); 544 tls_config_insecure_noverifycert(tls_cfg); 545 } 546 if (TLSopt & TLS_MUSTSTAPLE) 547 tls_config_ocsp_require_stapling(tls_cfg); 548 549 if (Pflag) { 550 if (pledge("stdio inet dns tty", NULL) == -1) 551 err(1, "pledge"); 552 } else if (pledge("stdio inet dns", NULL) == -1) 553 err(1, "pledge"); 554 } 555 if (lflag) { 556 ret = 0; 557 558 if (family == AF_UNIX) { 559 if (uflag) 560 s = unix_bind(host, 0); 561 else 562 s = unix_listen(host); 563 } 564 565 if (usetls) { 566 tls_config_verify_client_optional(tls_cfg); 567 if ((tls_ctx = tls_server()) == NULL) 568 errx(1, "tls server creation failed"); 569 if (tls_configure(tls_ctx, tls_cfg) == -1) 570 errx(1, "tls configuration failed (%s)", 571 tls_error(tls_ctx)); 572 } 573 /* Allow only one connection at a time, but stay alive. */ 574 for (;;) { 575 if (family != AF_UNIX) { 576 if (s != -1) 577 close(s); 578 s = local_listen(host, uport, hints); 579 } 580 if (s == -1) 581 err(1, NULL); 582 if (uflag && kflag) { 583 if (family == AF_UNIX) { 584 if (pledge("stdio unix", NULL) == -1) 585 err(1, "pledge"); 586 } 587 /* 588 * For UDP and -k, don't connect the socket, 589 * let it receive datagrams from multiple 590 * socket pairs. 591 */ 592 readwrite(s, NULL); 593 } else if (uflag && !kflag) { 594 /* 595 * For UDP and not -k, we will use recvfrom() 596 * initially to wait for a caller, then use 597 * the regular functions to talk to the caller. 598 */ 599 int rv; 600 char buf[2048]; 601 struct sockaddr_storage z; 602 603 len = sizeof(z); 604 rv = recvfrom(s, buf, sizeof(buf), MSG_PEEK, 605 (struct sockaddr *)&z, &len); 606 if (rv == -1) 607 err(1, "recvfrom"); 608 609 rv = connect(s, (struct sockaddr *)&z, len); 610 if (rv == -1) 611 err(1, "connect"); 612 613 if (family == AF_UNIX) { 614 if (pledge("stdio unix", NULL) == -1) 615 err(1, "pledge"); 616 } 617 if (vflag) 618 report_sock("Connection received", 619 (struct sockaddr *)&z, len, 620 family == AF_UNIX ? host : NULL); 621 622 readwrite(s, NULL); 623 } else { 624 struct tls *tls_cctx = NULL; 625 int connfd; 626 627 len = sizeof(cliaddr); 628 connfd = accept4(s, (struct sockaddr *)&cliaddr, 629 &len, SOCK_NONBLOCK); 630 if (connfd == -1) { 631 /* For now, all errnos are fatal */ 632 err(1, "accept"); 633 } 634 if (vflag) 635 report_sock("Connection received", 636 (struct sockaddr *)&cliaddr, len, 637 family == AF_UNIX ? host : NULL); 638 if ((usetls) && 639 (tls_cctx = tls_setup_server(tls_ctx, connfd, host))) 640 readwrite(connfd, tls_cctx); 641 if (!usetls) 642 readwrite(connfd, NULL); 643 if (tls_cctx) 644 timeout_tls(s, tls_cctx, tls_close); 645 close(connfd); 646 tls_free(tls_cctx); 647 } 648 if (family == AF_UNIX && uflag) { 649 if (connect(s, NULL, 0) == -1) 650 err(1, "connect"); 651 } 652 653 if (!kflag) 654 break; 655 } 656 } else if (family == AF_UNIX) { 657 ret = 0; 658 659 if ((s = unix_connect(host)) > 0) { 660 if (!zflag) 661 readwrite(s, NULL); 662 close(s); 663 } else { 664 warn("%s", host); 665 ret = 1; 666 } 667 668 if (uflag) 669 unlink(unix_dg_tmp_socket); 670 return ret; 671 672 } else { 673 int i = 0; 674 675 /* Construct the portlist[] array. */ 676 build_ports(uport); 677 678 /* Cycle through portlist, connecting to each port. */ 679 for (s = -1, i = 0; portlist[i] != NULL; i++) { 680 if (s != -1) 681 close(s); 682 tls_free(tls_ctx); 683 tls_ctx = NULL; 684 685 if (usetls) { 686 if ((tls_ctx = tls_client()) == NULL) 687 errx(1, "tls client creation failed"); 688 if (tls_configure(tls_ctx, tls_cfg) == -1) 689 errx(1, "tls configuration failed (%s)", 690 tls_error(tls_ctx)); 691 } 692 if (xflag) 693 s = socks_connect(host, portlist[i], hints, 694 proxy, proxyport, proxyhints, socksv, 695 Pflag); 696 else 697 s = remote_connect(host, portlist[i], hints, 698 ipaddr); 699 700 if (s == -1) 701 continue; 702 703 ret = 0; 704 if (vflag || zflag) { 705 /* For UDP, make sure we are connected. */ 706 if (uflag) { 707 if (udptest(s) == -1) { 708 ret = 1; 709 continue; 710 } 711 } 712 713 /* Don't look up port if -n. */ 714 if (nflag) 715 sv = NULL; 716 else { 717 sv = getservbyport( 718 ntohs(atoi(portlist[i])), 719 uflag ? "udp" : "tcp"); 720 } 721 722 fprintf(stderr, "Connection to %s", host); 723 724 /* 725 * if we aren't connecting thru a proxy and 726 * there is something to report, print IP 727 */ 728 if (!nflag && !xflag 729 && (strcmp(host, ipaddr) != 0)) 730 fprintf(stderr, " (%s)", ipaddr); 731 732 fprintf(stderr, " %s port [%s/%s] succeeded!\n", 733 portlist[i], uflag ? "udp" : "tcp", 734 sv ? sv->s_name : "*"); 735 } 736 if (Fflag) 737 fdpass(s); 738 else { 739 if (usetls) 740 tls_setup_client(tls_ctx, s, host); 741 if (!zflag) 742 readwrite(s, tls_ctx); 743 if (tls_ctx) 744 timeout_tls(s, tls_ctx, tls_close); 745 } 746 } 747 } 748 749 if (s != -1) 750 close(s); 751 tls_free(tls_ctx); 752 tls_config_free(tls_cfg); 753 754 return ret; 755 } 756 757 /* 758 * unix_bind() 759 * Returns a unix socket bound to the given path 760 */ 761 int 762 unix_bind(char *path, int flags) 763 { 764 struct sockaddr_un s_un; 765 int s, save_errno; 766 767 /* Create unix domain socket. */ 768 if ((s = socket(AF_UNIX, flags | (uflag ? SOCK_DGRAM : SOCK_STREAM), 769 0)) == -1) 770 return -1; 771 772 memset(&s_un, 0, sizeof(struct sockaddr_un)); 773 s_un.sun_family = AF_UNIX; 774 775 if (strlcpy(s_un.sun_path, path, sizeof(s_un.sun_path)) >= 776 sizeof(s_un.sun_path)) { 777 close(s); 778 errno = ENAMETOOLONG; 779 return -1; 780 } 781 782 if (bind(s, (struct sockaddr *)&s_un, sizeof(s_un)) == -1) { 783 save_errno = errno; 784 close(s); 785 errno = save_errno; 786 return -1; 787 } 788 if (vflag) 789 report_sock("Bound", NULL, 0, path); 790 791 return s; 792 } 793 794 int 795 timeout_tls(int s, struct tls *tls_ctx, int (*func)(struct tls *)) 796 { 797 struct pollfd pfd; 798 int ret; 799 800 while ((ret = (*func)(tls_ctx)) != 0) { 801 if (ret == TLS_WANT_POLLIN) 802 pfd.events = POLLIN; 803 else if (ret == TLS_WANT_POLLOUT) 804 pfd.events = POLLOUT; 805 else 806 break; 807 pfd.fd = s; 808 if ((ret = poll(&pfd, 1, timeout)) == 1) 809 continue; 810 else if (ret == 0) { 811 errno = ETIMEDOUT; 812 ret = -1; 813 break; 814 } else 815 err(1, "poll failed"); 816 } 817 818 return ret; 819 } 820 821 void 822 tls_setup_client(struct tls *tls_ctx, int s, char *host) 823 { 824 const char *errstr; 825 826 if (tls_connect_socket(tls_ctx, s, 827 tls_expectname ? tls_expectname : host) == -1) { 828 errx(1, "tls connection failed (%s)", 829 tls_error(tls_ctx)); 830 } 831 if (timeout_tls(s, tls_ctx, tls_handshake) == -1) { 832 if ((errstr = tls_error(tls_ctx)) == NULL) 833 errstr = strerror(errno); 834 errx(1, "tls handshake failed (%s)", errstr); 835 } 836 if (vflag) 837 report_tls(tls_ctx, host); 838 if (tls_expecthash && (tls_peer_cert_hash(tls_ctx) == NULL || 839 strcmp(tls_expecthash, tls_peer_cert_hash(tls_ctx)) != 0)) 840 errx(1, "peer certificate is not %s", tls_expecthash); 841 if (Zflag) { 842 save_peer_cert(tls_ctx, Zflag); 843 if (Zflag != stderr && (fclose(Zflag) != 0)) 844 err(1, "fclose failed saving peer cert"); 845 } 846 } 847 848 struct tls * 849 tls_setup_server(struct tls *tls_ctx, int connfd, char *host) 850 { 851 struct tls *tls_cctx; 852 const char *errstr; 853 854 if (tls_accept_socket(tls_ctx, &tls_cctx, connfd) == -1) { 855 warnx("tls accept failed (%s)", tls_error(tls_ctx)); 856 } else if (timeout_tls(connfd, tls_cctx, tls_handshake) == -1) { 857 if ((errstr = tls_error(tls_cctx)) == NULL) 858 errstr = strerror(errno); 859 warnx("tls handshake failed (%s)", errstr); 860 } else { 861 int gotcert = tls_peer_cert_provided(tls_cctx); 862 863 if (vflag && gotcert) 864 report_tls(tls_cctx, host); 865 if ((TLSopt & TLS_CCERT) && !gotcert) 866 warnx("No client certificate provided"); 867 else if (gotcert && tls_expecthash && 868 (tls_peer_cert_hash(tls_cctx) == NULL || 869 strcmp(tls_expecthash, tls_peer_cert_hash(tls_cctx)) != 0)) 870 warnx("peer certificate is not %s", tls_expecthash); 871 else if (gotcert && tls_expectname && 872 (!tls_peer_cert_contains_name(tls_cctx, tls_expectname))) 873 warnx("name (%s) not found in client cert", 874 tls_expectname); 875 else { 876 return tls_cctx; 877 } 878 } 879 return NULL; 880 } 881 882 /* 883 * unix_connect() 884 * Returns a socket connected to a local unix socket. Returns -1 on failure. 885 */ 886 int 887 unix_connect(char *path) 888 { 889 struct sockaddr_un s_un; 890 int s, save_errno; 891 892 if (uflag) { 893 if ((s = unix_bind(unix_dg_tmp_socket, SOCK_CLOEXEC)) == -1) 894 return -1; 895 } else { 896 if ((s = socket(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC, 0)) == -1) 897 return -1; 898 } 899 900 memset(&s_un, 0, sizeof(struct sockaddr_un)); 901 s_un.sun_family = AF_UNIX; 902 903 if (strlcpy(s_un.sun_path, path, sizeof(s_un.sun_path)) >= 904 sizeof(s_un.sun_path)) { 905 close(s); 906 errno = ENAMETOOLONG; 907 return -1; 908 } 909 if (connect(s, (struct sockaddr *)&s_un, sizeof(s_un)) == -1) { 910 save_errno = errno; 911 close(s); 912 errno = save_errno; 913 return -1; 914 } 915 return s; 916 917 } 918 919 /* 920 * unix_listen() 921 * Create a unix domain socket, and listen on it. 922 */ 923 int 924 unix_listen(char *path) 925 { 926 int s; 927 928 if ((s = unix_bind(path, 0)) == -1) 929 return -1; 930 if (listen(s, 5) == -1) { 931 close(s); 932 return -1; 933 } 934 if (vflag) 935 report_sock("Listening", NULL, 0, path); 936 937 return s; 938 } 939 940 /* 941 * remote_connect() 942 * Returns a socket connected to a remote host. Properly binds to a local 943 * port or source address if needed. Returns -1 on failure. 944 */ 945 int 946 remote_connect(const char *host, const char *port, struct addrinfo hints, 947 char *ipaddr) 948 { 949 struct addrinfo *res, *res0; 950 int s = -1, error, herr, on = 1, save_errno; 951 952 if ((error = getaddrinfo(host, port, &hints, &res0))) 953 errx(1, "getaddrinfo for host \"%s\" port %s: %s", host, 954 port, gai_strerror(error)); 955 956 for (res = res0; res; res = res->ai_next) { 957 if ((s = socket(res->ai_family, res->ai_socktype | 958 SOCK_NONBLOCK, res->ai_protocol)) == -1) 959 continue; 960 961 /* Bind to a local port or source address if specified. */ 962 if (sflag || pflag) { 963 struct addrinfo ahints, *ares; 964 965 /* try SO_BINDANY, but don't insist */ 966 setsockopt(s, SOL_SOCKET, SO_BINDANY, &on, sizeof(on)); 967 memset(&ahints, 0, sizeof(struct addrinfo)); 968 ahints.ai_family = res->ai_family; 969 ahints.ai_socktype = uflag ? SOCK_DGRAM : SOCK_STREAM; 970 ahints.ai_protocol = uflag ? IPPROTO_UDP : IPPROTO_TCP; 971 ahints.ai_flags = AI_PASSIVE; 972 if ((error = getaddrinfo(sflag, pflag, &ahints, &ares))) 973 errx(1, "getaddrinfo: %s", gai_strerror(error)); 974 975 if (bind(s, (struct sockaddr *)ares->ai_addr, 976 ares->ai_addrlen) == -1) 977 err(1, "bind failed"); 978 freeaddrinfo(ares); 979 } 980 981 set_common_sockopts(s, res->ai_family); 982 983 if (ipaddr != NULL) { 984 herr = getnameinfo(res->ai_addr, res->ai_addrlen, 985 ipaddr, NI_MAXHOST, NULL, 0, NI_NUMERICHOST); 986 switch (herr) { 987 case 0: 988 break; 989 case EAI_SYSTEM: 990 err(1, "getnameinfo"); 991 default: 992 errx(1, "getnameinfo: %s", gai_strerror(herr)); 993 } 994 } 995 996 if (timeout_connect(s, res->ai_addr, res->ai_addrlen) == 0) 997 break; 998 999 if (vflag) { 1000 /* only print IP if there is something to report */ 1001 if (nflag || ipaddr == NULL || 1002 (strncmp(host, ipaddr, NI_MAXHOST) == 0)) 1003 warn("connect to %s port %s (%s) failed", host, 1004 port, uflag ? "udp" : "tcp"); 1005 else 1006 warn("connect to %s (%s) port %s (%s) failed", 1007 host, ipaddr, port, uflag ? "udp" : "tcp"); 1008 } 1009 1010 save_errno = errno; 1011 close(s); 1012 errno = save_errno; 1013 s = -1; 1014 } 1015 1016 freeaddrinfo(res0); 1017 1018 return s; 1019 } 1020 1021 int 1022 timeout_connect(int s, const struct sockaddr *name, socklen_t namelen) 1023 { 1024 struct pollfd pfd; 1025 socklen_t optlen; 1026 int optval; 1027 int ret; 1028 1029 if ((ret = connect(s, name, namelen)) != 0 && errno == EINPROGRESS) { 1030 pfd.fd = s; 1031 pfd.events = POLLOUT; 1032 if ((ret = poll(&pfd, 1, timeout)) == 1) { 1033 optlen = sizeof(optval); 1034 if ((ret = getsockopt(s, SOL_SOCKET, SO_ERROR, 1035 &optval, &optlen)) == 0) { 1036 errno = optval; 1037 ret = optval == 0 ? 0 : -1; 1038 } 1039 } else if (ret == 0) { 1040 errno = ETIMEDOUT; 1041 ret = -1; 1042 } else 1043 err(1, "poll failed"); 1044 } 1045 1046 return ret; 1047 } 1048 1049 /* 1050 * local_listen() 1051 * Returns a socket listening on a local port, binds to specified source 1052 * address. Returns -1 on failure. 1053 */ 1054 int 1055 local_listen(const char *host, const char *port, struct addrinfo hints) 1056 { 1057 struct addrinfo *res, *res0; 1058 int s = -1, ret, x = 1, save_errno; 1059 int error; 1060 1061 /* Allow nodename to be null. */ 1062 hints.ai_flags |= AI_PASSIVE; 1063 1064 /* 1065 * In the case of binding to a wildcard address 1066 * default to binding to an ipv4 address. 1067 */ 1068 if (host == NULL && hints.ai_family == AF_UNSPEC) 1069 hints.ai_family = AF_INET; 1070 1071 if ((error = getaddrinfo(host, port, &hints, &res0))) 1072 errx(1, "getaddrinfo: %s", gai_strerror(error)); 1073 1074 for (res = res0; res; res = res->ai_next) { 1075 if ((s = socket(res->ai_family, res->ai_socktype, 1076 res->ai_protocol)) == -1) 1077 continue; 1078 1079 ret = setsockopt(s, SOL_SOCKET, SO_REUSEPORT, &x, sizeof(x)); 1080 if (ret == -1) 1081 err(1, NULL); 1082 1083 set_common_sockopts(s, res->ai_family); 1084 1085 if (bind(s, (struct sockaddr *)res->ai_addr, 1086 res->ai_addrlen) == 0) 1087 break; 1088 1089 save_errno = errno; 1090 close(s); 1091 errno = save_errno; 1092 s = -1; 1093 } 1094 1095 if (!uflag && s != -1) { 1096 if (listen(s, 1) == -1) 1097 err(1, "listen"); 1098 } 1099 if (vflag && s != -1) { 1100 struct sockaddr_storage ss; 1101 socklen_t len; 1102 1103 len = sizeof(ss); 1104 if (getsockname(s, (struct sockaddr *)&ss, &len) == -1) 1105 err(1, "getsockname"); 1106 report_sock(uflag ? "Bound" : "Listening", 1107 (struct sockaddr *)&ss, len, NULL); 1108 } 1109 1110 freeaddrinfo(res0); 1111 1112 return s; 1113 } 1114 1115 /* 1116 * readwrite() 1117 * Loop that polls on the network file descriptor and stdin. 1118 */ 1119 void 1120 readwrite(int net_fd, struct tls *tls_ctx) 1121 { 1122 struct pollfd pfd[4]; 1123 int stdin_fd = STDIN_FILENO; 1124 int stdout_fd = STDOUT_FILENO; 1125 unsigned char netinbuf[BUFSIZE]; 1126 size_t netinbufpos = 0; 1127 unsigned char stdinbuf[BUFSIZE]; 1128 size_t stdinbufpos = 0; 1129 int n, num_fds; 1130 ssize_t ret; 1131 1132 /* don't read from stdin if requested */ 1133 if (dflag) 1134 stdin_fd = -1; 1135 1136 /* stdin */ 1137 pfd[POLL_STDIN].fd = stdin_fd; 1138 pfd[POLL_STDIN].events = POLLIN; 1139 1140 /* network out */ 1141 pfd[POLL_NETOUT].fd = net_fd; 1142 pfd[POLL_NETOUT].events = 0; 1143 1144 /* network in */ 1145 pfd[POLL_NETIN].fd = net_fd; 1146 pfd[POLL_NETIN].events = POLLIN; 1147 1148 /* stdout */ 1149 pfd[POLL_STDOUT].fd = stdout_fd; 1150 pfd[POLL_STDOUT].events = 0; 1151 1152 while (1) { 1153 /* both inputs are gone, buffers are empty, we are done */ 1154 if (pfd[POLL_STDIN].fd == -1 && pfd[POLL_NETIN].fd == -1 && 1155 stdinbufpos == 0 && netinbufpos == 0) 1156 return; 1157 /* both outputs are gone, we can't continue */ 1158 if (pfd[POLL_NETOUT].fd == -1 && pfd[POLL_STDOUT].fd == -1) 1159 return; 1160 /* listen and net in gone, queues empty, done */ 1161 if (lflag && pfd[POLL_NETIN].fd == -1 && 1162 stdinbufpos == 0 && netinbufpos == 0) 1163 return; 1164 1165 /* help says -i is for "wait between lines sent". We read and 1166 * write arbitrary amounts of data, and we don't want to start 1167 * scanning for newlines, so this is as good as it gets */ 1168 if (iflag) 1169 sleep(iflag); 1170 1171 /* poll */ 1172 num_fds = poll(pfd, 4, timeout); 1173 1174 /* treat poll errors */ 1175 if (num_fds == -1) 1176 err(1, "polling error"); 1177 1178 /* timeout happened */ 1179 if (num_fds == 0) 1180 return; 1181 1182 /* treat socket error conditions */ 1183 for (n = 0; n < 4; n++) { 1184 if (pfd[n].revents & (POLLERR|POLLNVAL)) { 1185 pfd[n].fd = -1; 1186 } 1187 } 1188 /* reading is possible after HUP */ 1189 if (pfd[POLL_STDIN].events & POLLIN && 1190 pfd[POLL_STDIN].revents & POLLHUP && 1191 !(pfd[POLL_STDIN].revents & POLLIN)) 1192 pfd[POLL_STDIN].fd = -1; 1193 1194 if (pfd[POLL_NETIN].events & POLLIN && 1195 pfd[POLL_NETIN].revents & POLLHUP && 1196 !(pfd[POLL_NETIN].revents & POLLIN)) 1197 pfd[POLL_NETIN].fd = -1; 1198 1199 if (pfd[POLL_NETOUT].revents & POLLHUP) { 1200 if (Nflag) 1201 shutdown(pfd[POLL_NETOUT].fd, SHUT_WR); 1202 pfd[POLL_NETOUT].fd = -1; 1203 } 1204 /* if HUP, stop watching stdout */ 1205 if (pfd[POLL_STDOUT].revents & POLLHUP) 1206 pfd[POLL_STDOUT].fd = -1; 1207 /* if no net out, stop watching stdin */ 1208 if (pfd[POLL_NETOUT].fd == -1) 1209 pfd[POLL_STDIN].fd = -1; 1210 /* if no stdout, stop watching net in */ 1211 if (pfd[POLL_STDOUT].fd == -1) { 1212 if (pfd[POLL_NETIN].fd != -1) 1213 shutdown(pfd[POLL_NETIN].fd, SHUT_RD); 1214 pfd[POLL_NETIN].fd = -1; 1215 } 1216 1217 /* try to read from stdin */ 1218 if (pfd[POLL_STDIN].revents & POLLIN && stdinbufpos < BUFSIZE) { 1219 ret = fillbuf(pfd[POLL_STDIN].fd, stdinbuf, 1220 &stdinbufpos, NULL); 1221 if (ret == TLS_WANT_POLLIN) 1222 pfd[POLL_STDIN].events = POLLIN; 1223 else if (ret == TLS_WANT_POLLOUT) 1224 pfd[POLL_STDIN].events = POLLOUT; 1225 else if (ret == 0 || ret == -1) 1226 pfd[POLL_STDIN].fd = -1; 1227 /* read something - poll net out */ 1228 if (stdinbufpos > 0) 1229 pfd[POLL_NETOUT].events = POLLOUT; 1230 /* filled buffer - remove self from polling */ 1231 if (stdinbufpos == BUFSIZE) 1232 pfd[POLL_STDIN].events = 0; 1233 } 1234 /* try to write to network */ 1235 if (pfd[POLL_NETOUT].revents & POLLOUT && stdinbufpos > 0) { 1236 ret = drainbuf(pfd[POLL_NETOUT].fd, stdinbuf, 1237 &stdinbufpos, tls_ctx); 1238 if (ret == TLS_WANT_POLLIN) 1239 pfd[POLL_NETOUT].events = POLLIN; 1240 else if (ret == TLS_WANT_POLLOUT) 1241 pfd[POLL_NETOUT].events = POLLOUT; 1242 else if (ret == -1) 1243 pfd[POLL_NETOUT].fd = -1; 1244 /* buffer empty - remove self from polling */ 1245 if (stdinbufpos == 0) 1246 pfd[POLL_NETOUT].events = 0; 1247 /* buffer no longer full - poll stdin again */ 1248 if (stdinbufpos < BUFSIZE) 1249 pfd[POLL_STDIN].events = POLLIN; 1250 } 1251 /* try to read from network */ 1252 if (pfd[POLL_NETIN].revents & POLLIN && netinbufpos < BUFSIZE) { 1253 ret = fillbuf(pfd[POLL_NETIN].fd, netinbuf, 1254 &netinbufpos, tls_ctx); 1255 if (ret == TLS_WANT_POLLIN) 1256 pfd[POLL_NETIN].events = POLLIN; 1257 else if (ret == TLS_WANT_POLLOUT) 1258 pfd[POLL_NETIN].events = POLLOUT; 1259 else if (ret == -1) 1260 pfd[POLL_NETIN].fd = -1; 1261 /* eof on net in - remove from pfd */ 1262 if (ret == 0) { 1263 shutdown(pfd[POLL_NETIN].fd, SHUT_RD); 1264 pfd[POLL_NETIN].fd = -1; 1265 } 1266 if (recvlimit > 0 && ++recvcount >= recvlimit) { 1267 if (pfd[POLL_NETIN].fd != -1) 1268 shutdown(pfd[POLL_NETIN].fd, SHUT_RD); 1269 pfd[POLL_NETIN].fd = -1; 1270 pfd[POLL_STDIN].fd = -1; 1271 } 1272 /* read something - poll stdout */ 1273 if (netinbufpos > 0) 1274 pfd[POLL_STDOUT].events = POLLOUT; 1275 /* filled buffer - remove self from polling */ 1276 if (netinbufpos == BUFSIZE) 1277 pfd[POLL_NETIN].events = 0; 1278 /* handle telnet */ 1279 if (tflag) 1280 atelnet(pfd[POLL_NETIN].fd, netinbuf, 1281 netinbufpos); 1282 } 1283 /* try to write to stdout */ 1284 if (pfd[POLL_STDOUT].revents & POLLOUT && netinbufpos > 0) { 1285 ret = drainbuf(pfd[POLL_STDOUT].fd, netinbuf, 1286 &netinbufpos, NULL); 1287 if (ret == TLS_WANT_POLLIN) 1288 pfd[POLL_STDOUT].events = POLLIN; 1289 else if (ret == TLS_WANT_POLLOUT) 1290 pfd[POLL_STDOUT].events = POLLOUT; 1291 else if (ret == -1) 1292 pfd[POLL_STDOUT].fd = -1; 1293 /* buffer empty - remove self from polling */ 1294 if (netinbufpos == 0) 1295 pfd[POLL_STDOUT].events = 0; 1296 /* buffer no longer full - poll net in again */ 1297 if (netinbufpos < BUFSIZE) 1298 pfd[POLL_NETIN].events = POLLIN; 1299 } 1300 1301 /* stdin gone and queue empty? */ 1302 if (pfd[POLL_STDIN].fd == -1 && stdinbufpos == 0) { 1303 if (pfd[POLL_NETOUT].fd != -1 && Nflag) 1304 shutdown(pfd[POLL_NETOUT].fd, SHUT_WR); 1305 pfd[POLL_NETOUT].fd = -1; 1306 } 1307 /* net in gone and queue empty? */ 1308 if (pfd[POLL_NETIN].fd == -1 && netinbufpos == 0) { 1309 pfd[POLL_STDOUT].fd = -1; 1310 } 1311 } 1312 } 1313 1314 ssize_t 1315 drainbuf(int fd, unsigned char *buf, size_t *bufpos, struct tls *tls) 1316 { 1317 ssize_t n; 1318 ssize_t adjust; 1319 1320 if (tls) { 1321 n = tls_write(tls, buf, *bufpos); 1322 if (n == -1) 1323 errx(1, "tls write failed (%s)", tls_error(tls)); 1324 } else { 1325 n = write(fd, buf, *bufpos); 1326 /* don't treat EAGAIN, EINTR as error */ 1327 if (n == -1 && (errno == EAGAIN || errno == EINTR)) 1328 n = TLS_WANT_POLLOUT; 1329 } 1330 if (n <= 0) 1331 return n; 1332 /* adjust buffer */ 1333 adjust = *bufpos - n; 1334 if (adjust > 0) 1335 memmove(buf, buf + n, adjust); 1336 *bufpos -= n; 1337 return n; 1338 } 1339 1340 ssize_t 1341 fillbuf(int fd, unsigned char *buf, size_t *bufpos, struct tls *tls) 1342 { 1343 size_t num = BUFSIZE - *bufpos; 1344 ssize_t n; 1345 1346 if (tls) { 1347 n = tls_read(tls, buf + *bufpos, num); 1348 if (n == -1) 1349 errx(1, "tls read failed (%s)", tls_error(tls)); 1350 } else { 1351 n = read(fd, buf + *bufpos, num); 1352 /* don't treat EAGAIN, EINTR as error */ 1353 if (n == -1 && (errno == EAGAIN || errno == EINTR)) 1354 n = TLS_WANT_POLLIN; 1355 } 1356 if (n <= 0) 1357 return n; 1358 *bufpos += n; 1359 return n; 1360 } 1361 1362 /* 1363 * fdpass() 1364 * Pass the connected file descriptor to stdout and exit. 1365 */ 1366 void 1367 fdpass(int nfd) 1368 { 1369 struct msghdr mh; 1370 union { 1371 struct cmsghdr hdr; 1372 char buf[CMSG_SPACE(sizeof(int))]; 1373 } cmsgbuf; 1374 struct cmsghdr *cmsg; 1375 struct iovec iov; 1376 char c = '\0'; 1377 ssize_t r; 1378 struct pollfd pfd; 1379 1380 /* Avoid obvious stupidity */ 1381 if (isatty(STDOUT_FILENO)) 1382 errx(1, "Cannot pass file descriptor to tty"); 1383 1384 memset(&mh, 0, sizeof(mh)); 1385 memset(&cmsgbuf, 0, sizeof(cmsgbuf)); 1386 memset(&iov, 0, sizeof(iov)); 1387 1388 mh.msg_control = (caddr_t)&cmsgbuf.buf; 1389 mh.msg_controllen = sizeof(cmsgbuf.buf); 1390 cmsg = CMSG_FIRSTHDR(&mh); 1391 cmsg->cmsg_len = CMSG_LEN(sizeof(int)); 1392 cmsg->cmsg_level = SOL_SOCKET; 1393 cmsg->cmsg_type = SCM_RIGHTS; 1394 *(int *)CMSG_DATA(cmsg) = nfd; 1395 1396 iov.iov_base = &c; 1397 iov.iov_len = 1; 1398 mh.msg_iov = &iov; 1399 mh.msg_iovlen = 1; 1400 1401 memset(&pfd, 0, sizeof(pfd)); 1402 pfd.fd = STDOUT_FILENO; 1403 pfd.events = POLLOUT; 1404 for (;;) { 1405 r = sendmsg(STDOUT_FILENO, &mh, 0); 1406 if (r == -1) { 1407 if (errno == EAGAIN || errno == EINTR) { 1408 if (poll(&pfd, 1, -1) == -1) 1409 err(1, "poll"); 1410 continue; 1411 } 1412 err(1, "sendmsg"); 1413 } else if (r != 1) 1414 errx(1, "sendmsg: unexpected return value %zd", r); 1415 else 1416 break; 1417 } 1418 exit(0); 1419 } 1420 1421 /* Deal with RFC 854 WILL/WONT DO/DONT negotiation. */ 1422 void 1423 atelnet(int nfd, unsigned char *buf, unsigned int size) 1424 { 1425 unsigned char *p, *end; 1426 unsigned char obuf[4]; 1427 1428 if (size < 3) 1429 return; 1430 end = buf + size - 2; 1431 1432 for (p = buf; p < end; p++) { 1433 if (*p != IAC) 1434 continue; 1435 1436 obuf[0] = IAC; 1437 p++; 1438 if ((*p == WILL) || (*p == WONT)) 1439 obuf[1] = DONT; 1440 else if ((*p == DO) || (*p == DONT)) 1441 obuf[1] = WONT; 1442 else 1443 continue; 1444 1445 p++; 1446 obuf[2] = *p; 1447 if (atomicio(vwrite, nfd, obuf, 3) != 3) 1448 warn("Write Error!"); 1449 } 1450 } 1451 1452 1453 int 1454 strtoport(char *portstr, int udp) 1455 { 1456 struct servent *entry; 1457 const char *errstr; 1458 char *proto; 1459 int port = -1; 1460 1461 proto = udp ? "udp" : "tcp"; 1462 1463 port = strtonum(portstr, 1, PORT_MAX, &errstr); 1464 if (errstr == NULL) 1465 return port; 1466 if (errno != EINVAL) 1467 errx(1, "port number %s: %s", errstr, portstr); 1468 if ((entry = getservbyname(portstr, proto)) == NULL) 1469 errx(1, "service \"%s\" unknown", portstr); 1470 return ntohs(entry->s_port); 1471 } 1472 1473 /* 1474 * build_ports() 1475 * Build an array of ports in portlist[], listing each port 1476 * that we should try to connect to. 1477 */ 1478 void 1479 build_ports(char *p) 1480 { 1481 char *n; 1482 int hi, lo, cp; 1483 int x = 0; 1484 1485 if (isdigit((unsigned char)*p) && (n = strchr(p, '-')) != NULL) { 1486 *n = '\0'; 1487 n++; 1488 1489 /* Make sure the ports are in order: lowest->highest. */ 1490 hi = strtoport(n, uflag); 1491 lo = strtoport(p, uflag); 1492 if (lo > hi) { 1493 cp = hi; 1494 hi = lo; 1495 lo = cp; 1496 } 1497 1498 /* 1499 * Initialize portlist with a random permutation. Based on 1500 * Knuth, as in ip_randomid() in sys/netinet/ip_id.c. 1501 */ 1502 if (rflag) { 1503 for (x = 0; x <= hi - lo; x++) { 1504 cp = arc4random_uniform(x + 1); 1505 portlist[x] = portlist[cp]; 1506 if (asprintf(&portlist[cp], "%d", x + lo) == -1) 1507 err(1, "asprintf"); 1508 } 1509 } else { /* Load ports sequentially. */ 1510 for (cp = lo; cp <= hi; cp++) { 1511 if (asprintf(&portlist[x], "%d", cp) == -1) 1512 err(1, "asprintf"); 1513 x++; 1514 } 1515 } 1516 } else { 1517 char *tmp; 1518 1519 hi = strtoport(p, uflag); 1520 if (asprintf(&tmp, "%d", hi) != -1) 1521 portlist[0] = tmp; 1522 else 1523 err(1, NULL); 1524 } 1525 } 1526 1527 /* 1528 * udptest() 1529 * Do a few writes to see if the UDP port is there. 1530 * Fails once PF state table is full. 1531 */ 1532 int 1533 udptest(int s) 1534 { 1535 int i, ret; 1536 1537 for (i = 0; i <= 3; i++) { 1538 if (write(s, "X", 1) == 1) 1539 ret = 1; 1540 else 1541 ret = -1; 1542 } 1543 return ret; 1544 } 1545 1546 void 1547 set_common_sockopts(int s, int af) 1548 { 1549 int x = 1; 1550 1551 if (Sflag) { 1552 if (setsockopt(s, IPPROTO_TCP, TCP_MD5SIG, 1553 &x, sizeof(x)) == -1) 1554 err(1, NULL); 1555 } 1556 if (Dflag) { 1557 if (setsockopt(s, SOL_SOCKET, SO_DEBUG, 1558 &x, sizeof(x)) == -1) 1559 err(1, NULL); 1560 } 1561 if (Tflag != -1) { 1562 if (af == AF_INET && setsockopt(s, IPPROTO_IP, 1563 IP_TOS, &Tflag, sizeof(Tflag)) == -1) 1564 err(1, "set IP ToS"); 1565 1566 else if (af == AF_INET6 && setsockopt(s, IPPROTO_IPV6, 1567 IPV6_TCLASS, &Tflag, sizeof(Tflag)) == -1) 1568 err(1, "set IPv6 traffic class"); 1569 } 1570 if (Iflag) { 1571 if (setsockopt(s, SOL_SOCKET, SO_RCVBUF, 1572 &Iflag, sizeof(Iflag)) == -1) 1573 err(1, "set TCP receive buffer size"); 1574 } 1575 if (Oflag) { 1576 if (setsockopt(s, SOL_SOCKET, SO_SNDBUF, 1577 &Oflag, sizeof(Oflag)) == -1) 1578 err(1, "set TCP send buffer size"); 1579 } 1580 1581 if (ttl != -1) { 1582 if (af == AF_INET && setsockopt(s, IPPROTO_IP, 1583 IP_TTL, &ttl, sizeof(ttl))) 1584 err(1, "set IP TTL"); 1585 1586 else if (af == AF_INET6 && setsockopt(s, IPPROTO_IPV6, 1587 IPV6_UNICAST_HOPS, &ttl, sizeof(ttl))) 1588 err(1, "set IPv6 unicast hops"); 1589 } 1590 1591 if (minttl != -1) { 1592 if (af == AF_INET && setsockopt(s, IPPROTO_IP, 1593 IP_MINTTL, &minttl, sizeof(minttl))) 1594 err(1, "set IP min TTL"); 1595 1596 else if (af == AF_INET6 && setsockopt(s, IPPROTO_IPV6, 1597 IPV6_MINHOPCOUNT, &minttl, sizeof(minttl))) 1598 err(1, "set IPv6 min hop count"); 1599 } 1600 } 1601 1602 int 1603 process_tos_opt(char *s, int *val) 1604 { 1605 /* DiffServ Codepoints and other TOS mappings */ 1606 const struct toskeywords { 1607 const char *keyword; 1608 int val; 1609 } *t, toskeywords[] = { 1610 { "af11", IPTOS_DSCP_AF11 }, 1611 { "af12", IPTOS_DSCP_AF12 }, 1612 { "af13", IPTOS_DSCP_AF13 }, 1613 { "af21", IPTOS_DSCP_AF21 }, 1614 { "af22", IPTOS_DSCP_AF22 }, 1615 { "af23", IPTOS_DSCP_AF23 }, 1616 { "af31", IPTOS_DSCP_AF31 }, 1617 { "af32", IPTOS_DSCP_AF32 }, 1618 { "af33", IPTOS_DSCP_AF33 }, 1619 { "af41", IPTOS_DSCP_AF41 }, 1620 { "af42", IPTOS_DSCP_AF42 }, 1621 { "af43", IPTOS_DSCP_AF43 }, 1622 { "critical", IPTOS_PREC_CRITIC_ECP }, 1623 { "cs0", IPTOS_DSCP_CS0 }, 1624 { "cs1", IPTOS_DSCP_CS1 }, 1625 { "cs2", IPTOS_DSCP_CS2 }, 1626 { "cs3", IPTOS_DSCP_CS3 }, 1627 { "cs4", IPTOS_DSCP_CS4 }, 1628 { "cs5", IPTOS_DSCP_CS5 }, 1629 { "cs6", IPTOS_DSCP_CS6 }, 1630 { "cs7", IPTOS_DSCP_CS7 }, 1631 { "ef", IPTOS_DSCP_EF }, 1632 { "inetcontrol", IPTOS_PREC_INTERNETCONTROL }, 1633 { "lowdelay", IPTOS_LOWDELAY }, 1634 { "netcontrol", IPTOS_PREC_NETCONTROL }, 1635 { "reliability", IPTOS_RELIABILITY }, 1636 { "throughput", IPTOS_THROUGHPUT }, 1637 { NULL, -1 }, 1638 }; 1639 1640 for (t = toskeywords; t->keyword != NULL; t++) { 1641 if (strcmp(s, t->keyword) == 0) { 1642 *val = t->val; 1643 return 1; 1644 } 1645 } 1646 1647 return 0; 1648 } 1649 1650 int 1651 process_tls_opt(char *s, int *flags) 1652 { 1653 size_t len; 1654 char *v; 1655 1656 const struct tlskeywords { 1657 const char *keyword; 1658 int flag; 1659 char **value; 1660 } *t, tlskeywords[] = { 1661 { "ciphers", -1, &tls_ciphers }, 1662 { "clientcert", TLS_CCERT, NULL }, 1663 { "muststaple", TLS_MUSTSTAPLE, NULL }, 1664 { "noverify", TLS_NOVERIFY, NULL }, 1665 { "noname", TLS_NONAME, NULL }, 1666 { "protocols", -1, &tls_protocols }, 1667 { NULL, -1, NULL }, 1668 }; 1669 1670 len = strlen(s); 1671 if ((v = strchr(s, '=')) != NULL) { 1672 len = v - s; 1673 v++; 1674 } 1675 1676 for (t = tlskeywords; t->keyword != NULL; t++) { 1677 if (strlen(t->keyword) == len && 1678 strncmp(s, t->keyword, len) == 0) { 1679 if (t->value != NULL) { 1680 if (v == NULL) 1681 errx(1, "invalid tls value `%s'", s); 1682 *t->value = v; 1683 } else { 1684 *flags |= t->flag; 1685 } 1686 return 1; 1687 } 1688 } 1689 return 0; 1690 } 1691 1692 void 1693 save_peer_cert(struct tls *tls_ctx, FILE *fp) 1694 { 1695 const char *pem; 1696 size_t plen; 1697 1698 if ((pem = tls_peer_cert_chain_pem(tls_ctx, &plen)) == NULL) 1699 errx(1, "Can't get peer certificate"); 1700 if (fprintf(fp, "%.*s", (int)plen, pem) < 0) 1701 err(1, "unable to save peer cert"); 1702 if (fflush(fp) != 0) 1703 err(1, "unable to flush peer cert"); 1704 } 1705 1706 void 1707 report_tls(struct tls * tls_ctx, char * host) 1708 { 1709 time_t t; 1710 const char *ocsp_url; 1711 1712 fprintf(stderr, "TLS handshake negotiated %s/%s with host %s\n", 1713 tls_conn_version(tls_ctx), tls_conn_cipher(tls_ctx), host); 1714 fprintf(stderr, "Peer name: %s\n", 1715 tls_expectname ? tls_expectname : host); 1716 if (tls_peer_cert_subject(tls_ctx)) 1717 fprintf(stderr, "Subject: %s\n", 1718 tls_peer_cert_subject(tls_ctx)); 1719 if (tls_peer_cert_issuer(tls_ctx)) 1720 fprintf(stderr, "Issuer: %s\n", 1721 tls_peer_cert_issuer(tls_ctx)); 1722 if ((t = tls_peer_cert_notbefore(tls_ctx)) != -1) 1723 fprintf(stderr, "Valid From: %s", ctime(&t)); 1724 if ((t = tls_peer_cert_notafter(tls_ctx)) != -1) 1725 fprintf(stderr, "Valid Until: %s", ctime(&t)); 1726 if (tls_peer_cert_hash(tls_ctx)) 1727 fprintf(stderr, "Cert Hash: %s\n", 1728 tls_peer_cert_hash(tls_ctx)); 1729 ocsp_url = tls_peer_ocsp_url(tls_ctx); 1730 if (ocsp_url != NULL) 1731 fprintf(stderr, "OCSP URL: %s\n", ocsp_url); 1732 switch (tls_peer_ocsp_response_status(tls_ctx)) { 1733 case TLS_OCSP_RESPONSE_SUCCESSFUL: 1734 fprintf(stderr, "OCSP Stapling: %s\n", 1735 tls_peer_ocsp_result(tls_ctx) == NULL ? "" : 1736 tls_peer_ocsp_result(tls_ctx)); 1737 fprintf(stderr, 1738 " response_status=%d cert_status=%d crl_reason=%d\n", 1739 tls_peer_ocsp_response_status(tls_ctx), 1740 tls_peer_ocsp_cert_status(tls_ctx), 1741 tls_peer_ocsp_crl_reason(tls_ctx)); 1742 t = tls_peer_ocsp_this_update(tls_ctx); 1743 fprintf(stderr, " this update: %s", 1744 t != -1 ? ctime(&t) : "\n"); 1745 t = tls_peer_ocsp_next_update(tls_ctx); 1746 fprintf(stderr, " next update: %s", 1747 t != -1 ? ctime(&t) : "\n"); 1748 t = tls_peer_ocsp_revocation_time(tls_ctx); 1749 fprintf(stderr, " revocation: %s", 1750 t != -1 ? ctime(&t) : "\n"); 1751 break; 1752 case -1: 1753 break; 1754 default: 1755 fprintf(stderr, "OCSP Stapling: failure - response_status %d (%s)\n", 1756 tls_peer_ocsp_response_status(tls_ctx), 1757 tls_peer_ocsp_result(tls_ctx) == NULL ? "" : 1758 tls_peer_ocsp_result(tls_ctx)); 1759 break; 1760 1761 } 1762 } 1763 1764 void 1765 report_sock(const char *msg, const struct sockaddr *sa, socklen_t salen, 1766 char *path) 1767 { 1768 char host[NI_MAXHOST], port[NI_MAXSERV]; 1769 int herr; 1770 int flags = NI_NUMERICSERV; 1771 1772 if (path != NULL) { 1773 fprintf(stderr, "%s on %s\n", msg, path); 1774 return; 1775 } 1776 1777 if (nflag) 1778 flags |= NI_NUMERICHOST; 1779 1780 herr = getnameinfo(sa, salen, host, sizeof(host), port, sizeof(port), 1781 flags); 1782 switch (herr) { 1783 case 0: 1784 break; 1785 case EAI_SYSTEM: 1786 err(1, "getnameinfo"); 1787 default: 1788 errx(1, "getnameinfo: %s", gai_strerror(herr)); 1789 } 1790 1791 fprintf(stderr, "%s on %s %s\n", msg, host, port); 1792 } 1793 1794 void 1795 help(void) 1796 { 1797 usage(0); 1798 fprintf(stderr, "\tCommand Summary:\n\ 1799 \t-4 Use IPv4\n\ 1800 \t-6 Use IPv6\n\ 1801 \t-C certfile Public key file\n\ 1802 \t-c Use TLS\n\ 1803 \t-D Enable the debug socket option\n\ 1804 \t-d Detach from stdin\n\ 1805 \t-e name\t Required name in peer certificate\n\ 1806 \t-F Pass socket fd\n\ 1807 \t-H hash\t Hash string of peer certificate\n\ 1808 \t-h This help text\n\ 1809 \t-I length TCP receive buffer length\n\ 1810 \t-i interval Delay interval for lines sent, ports scanned\n\ 1811 \t-K keyfile Private key file\n\ 1812 \t-k Keep inbound sockets open for multiple connects\n\ 1813 \t-l Listen mode, for inbound connects\n\ 1814 \t-M ttl Outgoing TTL / Hop Limit\n\ 1815 \t-m minttl Minimum incoming TTL / Hop Limit\n\ 1816 \t-N Shutdown the network socket after EOF on stdin\n\ 1817 \t-n Suppress name/port resolutions\n\ 1818 \t-O length TCP send buffer length\n\ 1819 \t-o staplefile Staple file\n\ 1820 \t-P proxyuser\tUsername for proxy authentication\n\ 1821 \t-p port\t Specify local port for remote connects\n\ 1822 \t-R CAfile CA bundle\n\ 1823 \t-r Randomize remote ports\n\ 1824 \t-S Enable the TCP MD5 signature option\n\ 1825 \t-s sourceaddr Local source address\n\ 1826 \t-T keyword TOS value or TLS options\n\ 1827 \t-t Answer TELNET negotiation\n\ 1828 \t-U Use UNIX domain socket\n\ 1829 \t-u UDP mode\n\ 1830 \t-V rtable Specify alternate routing table\n\ 1831 \t-v Verbose\n\ 1832 \t-W recvlimit Terminate after receiving a number of packets\n\ 1833 \t-w timeout Timeout for connects and final net reads\n\ 1834 \t-X proto Proxy protocol: \"4\", \"5\" (SOCKS) or \"connect\"\n\ 1835 \t-x addr[:port]\tSpecify proxy address and port\n\ 1836 \t-Z Peer certificate file\n\ 1837 \t-z Zero-I/O mode [used for scanning]\n\ 1838 Port numbers can be individual or ranges: lo-hi [inclusive]\n"); 1839 exit(1); 1840 } 1841 1842 void 1843 usage(int ret) 1844 { 1845 fprintf(stderr, 1846 "usage: nc [-46cDdFhklNnrStUuvz] [-C certfile] [-e name] " 1847 "[-H hash] [-I length]\n" 1848 "\t [-i interval] [-K keyfile] [-M ttl] [-m minttl] [-O length]\n" 1849 "\t [-o staplefile] [-P proxy_username] [-p source_port] " 1850 "[-R CAfile]\n" 1851 "\t [-s sourceaddr] [-T keyword] [-V rtable] [-W recvlimit] " 1852 "[-w timeout]\n" 1853 "\t [-X proxy_protocol] [-x proxy_address[:port]] " 1854 "[-Z peercertfile]\n" 1855 "\t [destination] [port]\n"); 1856 if (ret) 1857 exit(1); 1858 } 1859