1 /* $OpenBSD: netcat.c,v 1.225 2023/01/04 12:53:38 deraadt 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 void connection_info(const char *, const char *, const char *, const char *); 135 int unix_bind(char *, int); 136 int unix_connect(char *); 137 int unix_listen(char *); 138 void set_common_sockopts(int, int); 139 int process_tos_opt(char *, int *); 140 int process_tls_opt(char *, int *); 141 void save_peer_cert(struct tls *_tls_ctx, FILE *_fp); 142 void report_sock(const char *, const struct sockaddr *, socklen_t, char *); 143 void report_tls(struct tls *tls_ctx, char * host); 144 void usage(int); 145 ssize_t drainbuf(int, unsigned char *, size_t *, struct tls *); 146 ssize_t fillbuf(int, unsigned char *, size_t *, struct tls *); 147 void tls_setup_client(struct tls *, int, char *); 148 struct tls *tls_setup_server(struct tls *, int, char *); 149 150 int 151 main(int argc, char *argv[]) 152 { 153 int ch, s = -1, ret, socksv; 154 char *host, *uport; 155 char ipaddr[NI_MAXHOST]; 156 struct addrinfo hints; 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 Rflag = tls_default_ca_cert_file(); 172 173 signal(SIGPIPE, SIG_IGN); 174 175 while ((ch = getopt(argc, argv, 176 "46C:cDde:FH:hI:i:K:klM:m:NnO:o:P:p:R:rSs:T:tUuV:vW:w:X:x:Z:z")) 177 != -1) { 178 switch (ch) { 179 case '4': 180 family = AF_INET; 181 break; 182 case '6': 183 family = AF_INET6; 184 break; 185 case 'U': 186 family = AF_UNIX; 187 break; 188 case 'X': 189 if (strcasecmp(optarg, "connect") == 0) 190 socksv = -1; /* HTTP proxy CONNECT */ 191 else if (strcmp(optarg, "4") == 0) 192 socksv = 4; /* SOCKS v.4 */ 193 else if (strcmp(optarg, "5") == 0) 194 socksv = 5; /* SOCKS v.5 */ 195 else 196 errx(1, "unsupported proxy protocol"); 197 break; 198 case 'C': 199 Cflag = optarg; 200 break; 201 case 'c': 202 usetls = 1; 203 break; 204 case 'd': 205 dflag = 1; 206 break; 207 case 'e': 208 tls_expectname = optarg; 209 break; 210 case 'F': 211 Fflag = 1; 212 break; 213 case 'H': 214 tls_expecthash = optarg; 215 break; 216 case 'h': 217 help(); 218 break; 219 case 'i': 220 iflag = strtonum(optarg, 0, UINT_MAX, &errstr); 221 if (errstr) 222 errx(1, "interval %s: %s", errstr, optarg); 223 break; 224 case 'K': 225 Kflag = optarg; 226 break; 227 case 'k': 228 kflag = 1; 229 break; 230 case 'l': 231 lflag = 1; 232 break; 233 case 'M': 234 ttl = strtonum(optarg, 0, 255, &errstr); 235 if (errstr) 236 errx(1, "ttl is %s", errstr); 237 break; 238 case 'm': 239 minttl = strtonum(optarg, 0, 255, &errstr); 240 if (errstr) 241 errx(1, "minttl is %s", errstr); 242 break; 243 case 'N': 244 Nflag = 1; 245 break; 246 case 'n': 247 nflag = 1; 248 break; 249 case 'P': 250 Pflag = optarg; 251 break; 252 case 'p': 253 pflag = optarg; 254 break; 255 case 'R': 256 tls_cachanged = 1; 257 Rflag = optarg; 258 break; 259 case 'r': 260 rflag = 1; 261 break; 262 case 's': 263 sflag = optarg; 264 break; 265 case 't': 266 tflag = 1; 267 break; 268 case 'u': 269 uflag = 1; 270 break; 271 case 'V': 272 rtableid = (int)strtonum(optarg, 0, 273 RT_TABLEID_MAX, &errstr); 274 if (errstr) 275 errx(1, "rtable %s: %s", errstr, optarg); 276 break; 277 case 'v': 278 vflag = 1; 279 break; 280 case 'W': 281 recvlimit = strtonum(optarg, 1, INT_MAX, &errstr); 282 if (errstr) 283 errx(1, "receive limit %s: %s", errstr, optarg); 284 break; 285 case 'w': 286 timeout = strtonum(optarg, 0, INT_MAX / 1000, &errstr); 287 if (errstr) 288 errx(1, "timeout %s: %s", errstr, optarg); 289 timeout *= 1000; 290 break; 291 case 'x': 292 xflag = 1; 293 if ((proxy = strdup(optarg)) == NULL) 294 err(1, NULL); 295 break; 296 case 'Z': 297 if (strcmp(optarg, "-") == 0) 298 Zflag = stderr; 299 else if ((Zflag = fopen(optarg, "w")) == NULL) 300 err(1, "can't open %s", optarg); 301 break; 302 case 'z': 303 zflag = 1; 304 break; 305 case 'D': 306 Dflag = 1; 307 break; 308 case 'I': 309 Iflag = strtonum(optarg, 1, 65536 << 14, &errstr); 310 if (errstr != NULL) 311 errx(1, "TCP receive window %s: %s", 312 errstr, optarg); 313 break; 314 case 'O': 315 Oflag = strtonum(optarg, 1, 65536 << 14, &errstr); 316 if (errstr != NULL) 317 errx(1, "TCP send window %s: %s", 318 errstr, optarg); 319 break; 320 case 'o': 321 oflag = optarg; 322 break; 323 case 'S': 324 Sflag = 1; 325 break; 326 case 'T': 327 errstr = NULL; 328 errno = 0; 329 if (process_tls_opt(optarg, &TLSopt)) 330 break; 331 if (process_tos_opt(optarg, &Tflag)) 332 break; 333 if (strlen(optarg) > 1 && optarg[0] == '0' && 334 optarg[1] == 'x') 335 Tflag = (int)strtol(optarg, NULL, 16); 336 else 337 Tflag = (int)strtonum(optarg, 0, 255, 338 &errstr); 339 if (Tflag < 0 || Tflag > 255 || errstr || errno) 340 errx(1, "illegal tos/tls value %s", optarg); 341 break; 342 default: 343 usage(1); 344 } 345 } 346 argc -= optind; 347 argv += optind; 348 349 if (rtableid >= 0) 350 if (setrtable(rtableid) == -1) 351 err(1, "setrtable"); 352 353 /* Cruft to make sure options are clean, and used properly. */ 354 if (argc == 1 && family == AF_UNIX) { 355 host = argv[0]; 356 } else if (argc == 1 && lflag) { 357 uport = argv[0]; 358 } else if (argc == 2) { 359 host = argv[0]; 360 uport = argv[1]; 361 } else 362 usage(1); 363 364 if (usetls) { 365 if (Cflag && unveil(Cflag, "r") == -1) 366 err(1, "unveil %s", Cflag); 367 if (unveil(Rflag, "r") == -1) 368 err(1, "unveil %s", Rflag); 369 if (Kflag && unveil(Kflag, "r") == -1) 370 err(1, "unveil %s", Kflag); 371 if (oflag && unveil(oflag, "r") == -1) 372 err(1, "unveil %s", oflag); 373 } else if (family == AF_UNIX && uflag && lflag && !kflag) { 374 /* 375 * After recvfrom(2) from client, the server connects 376 * to the client socket. As the client path is determined 377 * during runtime, we cannot unveil(2). 378 */ 379 } else { 380 if (family == AF_UNIX) { 381 if (unveil(host, "rwc") == -1) 382 err(1, "unveil %s", host); 383 if (uflag && !kflag) { 384 if (sflag) { 385 if (unveil(sflag, "rwc") == -1) 386 err(1, "unveil %s", sflag); 387 } else { 388 if (unveil("/tmp", "rwc") == -1) 389 err(1, "unveil /tmp"); 390 } 391 } 392 } else { 393 /* no filesystem visibility */ 394 if (unveil("/", "") == -1) 395 err(1, "unveil /"); 396 } 397 } 398 399 if (family == AF_UNIX) { 400 if (pledge("stdio rpath wpath cpath tmppath unix", NULL) == -1) 401 err(1, "pledge"); 402 } else if (Fflag && Pflag) { 403 if (pledge("stdio inet dns sendfd tty", NULL) == -1) 404 err(1, "pledge"); 405 } else if (Fflag) { 406 if (pledge("stdio inet dns sendfd", NULL) == -1) 407 err(1, "pledge"); 408 } else if (Pflag && usetls) { 409 if (pledge("stdio rpath inet dns tty", NULL) == -1) 410 err(1, "pledge"); 411 } else if (Pflag) { 412 if (pledge("stdio inet dns tty", NULL) == -1) 413 err(1, "pledge"); 414 } else if (usetls) { 415 if (pledge("stdio rpath inet dns", NULL) == -1) 416 err(1, "pledge"); 417 } else if (pledge("stdio inet dns", NULL) == -1) 418 err(1, "pledge"); 419 420 if (lflag && sflag) 421 errx(1, "cannot use -s and -l"); 422 if (lflag && pflag) 423 errx(1, "cannot use -p and -l"); 424 if (lflag && zflag) 425 errx(1, "cannot use -z and -l"); 426 if (!lflag && kflag) 427 errx(1, "must use -l with -k"); 428 if (uflag && usetls) 429 errx(1, "cannot use -c and -u"); 430 if ((family == AF_UNIX) && usetls) 431 errx(1, "cannot use -c and -U"); 432 if ((family == AF_UNIX) && Fflag) 433 errx(1, "cannot use -F and -U"); 434 if (Fflag && usetls) 435 errx(1, "cannot use -c and -F"); 436 if (TLSopt && !usetls) 437 errx(1, "you must specify -c to use TLS options"); 438 if (Cflag && !usetls) 439 errx(1, "you must specify -c to use -C"); 440 if (Kflag && !usetls) 441 errx(1, "you must specify -c to use -K"); 442 if (Zflag && !usetls) 443 errx(1, "you must specify -c to use -Z"); 444 if (oflag && !Cflag) 445 errx(1, "you must specify -C to use -o"); 446 if (tls_cachanged && !usetls) 447 errx(1, "you must specify -c to use -R"); 448 if (tls_expecthash && !usetls) 449 errx(1, "you must specify -c to use -H"); 450 if (tls_expectname && !usetls) 451 errx(1, "you must specify -c to use -e"); 452 453 /* Get name of temporary socket for unix datagram client */ 454 if ((family == AF_UNIX) && uflag && !lflag) { 455 if (sflag) { 456 unix_dg_tmp_socket = sflag; 457 } else { 458 strlcpy(unix_dg_tmp_socket_buf, "/tmp/nc.XXXXXXXXXX", 459 UNIX_DG_TMP_SOCKET_SIZE); 460 if (mktemp(unix_dg_tmp_socket_buf) == NULL) 461 err(1, "mktemp"); 462 unix_dg_tmp_socket = unix_dg_tmp_socket_buf; 463 } 464 } 465 466 /* Initialize addrinfo structure. */ 467 if (family != AF_UNIX) { 468 memset(&hints, 0, sizeof(struct addrinfo)); 469 hints.ai_family = family; 470 hints.ai_socktype = uflag ? SOCK_DGRAM : SOCK_STREAM; 471 hints.ai_protocol = uflag ? IPPROTO_UDP : IPPROTO_TCP; 472 if (nflag) 473 hints.ai_flags |= AI_NUMERICHOST; 474 } 475 476 if (xflag) { 477 if (uflag) 478 errx(1, "no proxy support for UDP mode"); 479 480 if (lflag) 481 errx(1, "no proxy support for listen"); 482 483 if (family == AF_UNIX) 484 errx(1, "no proxy support for unix sockets"); 485 486 if (sflag) 487 errx(1, "no proxy support for local source address"); 488 489 if (*proxy == '[') { 490 ++proxy; 491 proxyport = strchr(proxy, ']'); 492 if (proxyport == NULL) 493 errx(1, "missing closing bracket in proxy"); 494 *proxyport++ = '\0'; 495 if (*proxyport == '\0') 496 /* Use default proxy port. */ 497 proxyport = NULL; 498 else { 499 if (*proxyport == ':') 500 ++proxyport; 501 else 502 errx(1, "garbage proxy port delimiter"); 503 } 504 } else { 505 proxyport = strrchr(proxy, ':'); 506 if (proxyport != NULL) 507 *proxyport++ = '\0'; 508 } 509 510 memset(&proxyhints, 0, sizeof(struct addrinfo)); 511 proxyhints.ai_family = family; 512 proxyhints.ai_socktype = SOCK_STREAM; 513 proxyhints.ai_protocol = IPPROTO_TCP; 514 if (nflag) 515 proxyhints.ai_flags |= AI_NUMERICHOST; 516 } 517 518 if (usetls) { 519 if ((tls_cfg = tls_config_new()) == NULL) 520 errx(1, "unable to allocate TLS config"); 521 if (Rflag && tls_config_set_ca_file(tls_cfg, Rflag) == -1) 522 errx(1, "%s", tls_config_error(tls_cfg)); 523 if (Cflag && tls_config_set_cert_file(tls_cfg, Cflag) == -1) 524 errx(1, "%s", tls_config_error(tls_cfg)); 525 if (Kflag && tls_config_set_key_file(tls_cfg, Kflag) == -1) 526 errx(1, "%s", tls_config_error(tls_cfg)); 527 if (oflag && tls_config_set_ocsp_staple_file(tls_cfg, oflag) == -1) 528 errx(1, "%s", tls_config_error(tls_cfg)); 529 if (tls_config_parse_protocols(&protocols, tls_protocols) == -1) 530 errx(1, "invalid TLS protocols `%s'", tls_protocols); 531 if (tls_config_set_protocols(tls_cfg, protocols) == -1) 532 errx(1, "%s", tls_config_error(tls_cfg)); 533 if (tls_config_set_ciphers(tls_cfg, tls_ciphers) == -1) 534 errx(1, "%s", tls_config_error(tls_cfg)); 535 if (!lflag && (TLSopt & TLS_CCERT)) 536 errx(1, "clientcert is only valid with -l"); 537 if (TLSopt & TLS_NONAME) 538 tls_config_insecure_noverifyname(tls_cfg); 539 if (TLSopt & TLS_NOVERIFY) { 540 if (tls_expecthash != NULL) 541 errx(1, "-H and -T noverify may not be used " 542 "together"); 543 tls_config_insecure_noverifycert(tls_cfg); 544 } 545 if (TLSopt & TLS_MUSTSTAPLE) 546 tls_config_ocsp_require_stapling(tls_cfg); 547 548 if (Pflag) { 549 if (pledge("stdio inet dns tty", NULL) == -1) 550 err(1, "pledge"); 551 } else if (pledge("stdio inet dns", NULL) == -1) 552 err(1, "pledge"); 553 } 554 if (lflag) { 555 ret = 0; 556 557 if (family == AF_UNIX) { 558 if (uflag) 559 s = unix_bind(host, 0); 560 else 561 s = unix_listen(host); 562 } 563 564 if (usetls) { 565 tls_config_verify_client_optional(tls_cfg); 566 if ((tls_ctx = tls_server()) == NULL) 567 errx(1, "tls server creation failed"); 568 if (tls_configure(tls_ctx, tls_cfg) == -1) 569 errx(1, "tls configuration failed (%s)", 570 tls_error(tls_ctx)); 571 } 572 /* Allow only one connection at a time, but stay alive. */ 573 for (;;) { 574 if (family != AF_UNIX) { 575 if (s != -1) 576 close(s); 577 s = local_listen(host, uport, hints); 578 } 579 if (s == -1) 580 err(1, NULL); 581 if (uflag && kflag) { 582 if (family == AF_UNIX) { 583 if (pledge("stdio unix", NULL) == -1) 584 err(1, "pledge"); 585 } 586 /* 587 * For UDP and -k, don't connect the socket, 588 * let it receive datagrams from multiple 589 * socket pairs. 590 */ 591 readwrite(s, NULL); 592 } else if (uflag && !kflag) { 593 /* 594 * For UDP and not -k, we will use recvfrom() 595 * initially to wait for a caller, then use 596 * the regular functions to talk to the caller. 597 */ 598 int rv; 599 char buf[2048]; 600 struct sockaddr_storage z; 601 602 len = sizeof(z); 603 rv = recvfrom(s, buf, sizeof(buf), MSG_PEEK, 604 (struct sockaddr *)&z, &len); 605 if (rv == -1) 606 err(1, "recvfrom"); 607 608 rv = connect(s, (struct sockaddr *)&z, len); 609 if (rv == -1) 610 err(1, "connect"); 611 612 if (family == AF_UNIX) { 613 if (pledge("stdio unix", NULL) == -1) 614 err(1, "pledge"); 615 } 616 if (vflag) 617 report_sock("Connection received", 618 (struct sockaddr *)&z, len, 619 family == AF_UNIX ? host : NULL); 620 621 readwrite(s, NULL); 622 } else { 623 struct tls *tls_cctx = NULL; 624 int connfd; 625 626 len = sizeof(cliaddr); 627 connfd = accept4(s, (struct sockaddr *)&cliaddr, 628 &len, SOCK_NONBLOCK); 629 if (connfd == -1) { 630 /* For now, all errnos are fatal */ 631 err(1, "accept"); 632 } 633 if (vflag) 634 report_sock("Connection received", 635 (struct sockaddr *)&cliaddr, len, 636 family == AF_UNIX ? host : NULL); 637 if ((usetls) && 638 (tls_cctx = tls_setup_server(tls_ctx, connfd, host))) 639 readwrite(connfd, tls_cctx); 640 if (!usetls) 641 readwrite(connfd, NULL); 642 if (tls_cctx) 643 timeout_tls(s, tls_cctx, tls_close); 644 close(connfd); 645 tls_free(tls_cctx); 646 } 647 if (family == AF_UNIX && uflag) { 648 if (connect(s, NULL, 0) == -1) 649 err(1, "connect"); 650 } 651 652 if (!kflag) 653 break; 654 } 655 } else if (family == AF_UNIX) { 656 ret = 0; 657 658 if ((s = unix_connect(host)) > 0) { 659 if (!zflag) 660 readwrite(s, NULL); 661 close(s); 662 } else { 663 warn("%s", host); 664 ret = 1; 665 } 666 667 if (uflag) 668 unlink(unix_dg_tmp_socket); 669 return ret; 670 } else { 671 int i = 0; 672 673 /* Construct the portlist[] array. */ 674 build_ports(uport); 675 676 /* Cycle through portlist, connecting to each port. */ 677 for (s = -1, i = 0; portlist[i] != NULL; i++) { 678 if (s != -1) 679 close(s); 680 tls_free(tls_ctx); 681 tls_ctx = NULL; 682 683 if (usetls) { 684 if ((tls_ctx = tls_client()) == NULL) 685 errx(1, "tls client creation failed"); 686 if (tls_configure(tls_ctx, tls_cfg) == -1) 687 errx(1, "tls configuration failed (%s)", 688 tls_error(tls_ctx)); 689 } 690 if (xflag) 691 s = socks_connect(host, portlist[i], hints, 692 proxy, proxyport, proxyhints, socksv, 693 Pflag); 694 else 695 s = remote_connect(host, portlist[i], hints, 696 ipaddr); 697 698 if (s == -1) 699 continue; 700 701 ret = 0; 702 if (vflag || zflag) { 703 int print_info = 1; 704 705 /* For UDP, make sure we are connected. */ 706 if (uflag) { 707 /* No info on failed or skipped test. */ 708 if ((print_info = udptest(s)) == -1) { 709 ret = 1; 710 continue; 711 } 712 } 713 if (print_info == 1) 714 connection_info(host, portlist[i], 715 uflag ? "udp" : "tcp", ipaddr); 716 } 717 if (Fflag) 718 fdpass(s); 719 else { 720 if (usetls) 721 tls_setup_client(tls_ctx, s, host); 722 if (!zflag) 723 readwrite(s, tls_ctx); 724 if (tls_ctx) 725 timeout_tls(s, tls_ctx, tls_close); 726 } 727 } 728 } 729 730 if (s != -1) 731 close(s); 732 tls_free(tls_ctx); 733 tls_config_free(tls_cfg); 734 735 return ret; 736 } 737 738 /* 739 * unix_bind() 740 * Returns a unix socket bound to the given path 741 */ 742 int 743 unix_bind(char *path, int flags) 744 { 745 struct sockaddr_un s_un; 746 int s, save_errno; 747 748 /* Create unix domain socket. */ 749 if ((s = socket(AF_UNIX, flags | (uflag ? SOCK_DGRAM : SOCK_STREAM), 750 0)) == -1) 751 return -1; 752 753 memset(&s_un, 0, sizeof(struct sockaddr_un)); 754 s_un.sun_family = AF_UNIX; 755 756 if (strlcpy(s_un.sun_path, path, sizeof(s_un.sun_path)) >= 757 sizeof(s_un.sun_path)) { 758 close(s); 759 errno = ENAMETOOLONG; 760 return -1; 761 } 762 763 if (bind(s, (struct sockaddr *)&s_un, sizeof(s_un)) == -1) { 764 save_errno = errno; 765 close(s); 766 errno = save_errno; 767 return -1; 768 } 769 if (vflag) 770 report_sock("Bound", NULL, 0, path); 771 772 return s; 773 } 774 775 int 776 timeout_tls(int s, struct tls *tls_ctx, int (*func)(struct tls *)) 777 { 778 struct pollfd pfd; 779 int ret; 780 781 while ((ret = (*func)(tls_ctx)) != 0) { 782 if (ret == TLS_WANT_POLLIN) 783 pfd.events = POLLIN; 784 else if (ret == TLS_WANT_POLLOUT) 785 pfd.events = POLLOUT; 786 else 787 break; 788 pfd.fd = s; 789 if ((ret = poll(&pfd, 1, timeout)) == 1) 790 continue; 791 else if (ret == 0) { 792 errno = ETIMEDOUT; 793 ret = -1; 794 break; 795 } else 796 err(1, "poll failed"); 797 } 798 799 return ret; 800 } 801 802 void 803 tls_setup_client(struct tls *tls_ctx, int s, char *host) 804 { 805 const char *errstr; 806 807 if (tls_connect_socket(tls_ctx, s, 808 tls_expectname ? tls_expectname : host) == -1) { 809 errx(1, "tls connection failed (%s)", 810 tls_error(tls_ctx)); 811 } 812 if (timeout_tls(s, tls_ctx, tls_handshake) == -1) { 813 if ((errstr = tls_error(tls_ctx)) == NULL) 814 errstr = strerror(errno); 815 errx(1, "tls handshake failed (%s)", errstr); 816 } 817 if (vflag) 818 report_tls(tls_ctx, host); 819 if (tls_expecthash && (tls_peer_cert_hash(tls_ctx) == NULL || 820 strcmp(tls_expecthash, tls_peer_cert_hash(tls_ctx)) != 0)) 821 errx(1, "peer certificate is not %s", tls_expecthash); 822 if (Zflag) { 823 save_peer_cert(tls_ctx, Zflag); 824 if (Zflag != stderr && (fclose(Zflag) != 0)) 825 err(1, "fclose failed saving peer cert"); 826 } 827 } 828 829 struct tls * 830 tls_setup_server(struct tls *tls_ctx, int connfd, char *host) 831 { 832 struct tls *tls_cctx; 833 const char *errstr; 834 835 if (tls_accept_socket(tls_ctx, &tls_cctx, connfd) == -1) { 836 warnx("tls accept failed (%s)", tls_error(tls_ctx)); 837 } else if (timeout_tls(connfd, tls_cctx, tls_handshake) == -1) { 838 if ((errstr = tls_error(tls_cctx)) == NULL) 839 errstr = strerror(errno); 840 warnx("tls handshake failed (%s)", errstr); 841 } else { 842 int gotcert = tls_peer_cert_provided(tls_cctx); 843 844 if (vflag && gotcert) 845 report_tls(tls_cctx, host); 846 if ((TLSopt & TLS_CCERT) && !gotcert) 847 warnx("No client certificate provided"); 848 else if (gotcert && tls_expecthash && 849 (tls_peer_cert_hash(tls_cctx) == NULL || 850 strcmp(tls_expecthash, tls_peer_cert_hash(tls_cctx)) != 0)) 851 warnx("peer certificate is not %s", tls_expecthash); 852 else if (gotcert && tls_expectname && 853 (!tls_peer_cert_contains_name(tls_cctx, tls_expectname))) 854 warnx("name (%s) not found in client cert", 855 tls_expectname); 856 else { 857 return tls_cctx; 858 } 859 } 860 return NULL; 861 } 862 863 /* 864 * unix_connect() 865 * Returns a socket connected to a local unix socket. Returns -1 on failure. 866 */ 867 int 868 unix_connect(char *path) 869 { 870 struct sockaddr_un s_un; 871 int s, save_errno; 872 873 if (uflag) { 874 if ((s = unix_bind(unix_dg_tmp_socket, SOCK_CLOEXEC)) == -1) 875 return -1; 876 } else { 877 if ((s = socket(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC, 0)) == -1) 878 return -1; 879 } 880 881 memset(&s_un, 0, sizeof(struct sockaddr_un)); 882 s_un.sun_family = AF_UNIX; 883 884 if (strlcpy(s_un.sun_path, path, sizeof(s_un.sun_path)) >= 885 sizeof(s_un.sun_path)) { 886 close(s); 887 errno = ENAMETOOLONG; 888 return -1; 889 } 890 if (connect(s, (struct sockaddr *)&s_un, sizeof(s_un)) == -1) { 891 save_errno = errno; 892 close(s); 893 errno = save_errno; 894 return -1; 895 } 896 return s; 897 } 898 899 /* 900 * unix_listen() 901 * Create a unix domain socket, and listen on it. 902 */ 903 int 904 unix_listen(char *path) 905 { 906 int s; 907 908 if ((s = unix_bind(path, 0)) == -1) 909 return -1; 910 if (listen(s, 5) == -1) { 911 close(s); 912 return -1; 913 } 914 if (vflag) 915 report_sock("Listening", NULL, 0, path); 916 917 return s; 918 } 919 920 /* 921 * remote_connect() 922 * Returns a socket connected to a remote host. Properly binds to a local 923 * port or source address if needed. Returns -1 on failure. 924 */ 925 int 926 remote_connect(const char *host, const char *port, struct addrinfo hints, 927 char *ipaddr) 928 { 929 struct addrinfo *res, *res0; 930 int s = -1, error, herr, on = 1, save_errno; 931 932 if ((error = getaddrinfo(host, port, &hints, &res0))) 933 errx(1, "getaddrinfo for host \"%s\" port %s: %s", host, 934 port, gai_strerror(error)); 935 936 for (res = res0; res; res = res->ai_next) { 937 if ((s = socket(res->ai_family, res->ai_socktype | 938 SOCK_NONBLOCK, res->ai_protocol)) == -1) 939 continue; 940 941 /* Bind to a local port or source address if specified. */ 942 if (sflag || pflag) { 943 struct addrinfo ahints, *ares; 944 945 /* try SO_BINDANY, but don't insist */ 946 setsockopt(s, SOL_SOCKET, SO_BINDANY, &on, sizeof(on)); 947 memset(&ahints, 0, sizeof(struct addrinfo)); 948 ahints.ai_family = res->ai_family; 949 ahints.ai_socktype = uflag ? SOCK_DGRAM : SOCK_STREAM; 950 ahints.ai_protocol = uflag ? IPPROTO_UDP : IPPROTO_TCP; 951 ahints.ai_flags = AI_PASSIVE; 952 if ((error = getaddrinfo(sflag, pflag, &ahints, &ares))) 953 errx(1, "getaddrinfo: %s", gai_strerror(error)); 954 955 if (bind(s, (struct sockaddr *)ares->ai_addr, 956 ares->ai_addrlen) == -1) 957 err(1, "bind failed"); 958 freeaddrinfo(ares); 959 } 960 961 set_common_sockopts(s, res->ai_family); 962 963 if (ipaddr != NULL) { 964 herr = getnameinfo(res->ai_addr, res->ai_addrlen, 965 ipaddr, NI_MAXHOST, NULL, 0, NI_NUMERICHOST); 966 switch (herr) { 967 case 0: 968 break; 969 case EAI_SYSTEM: 970 err(1, "getnameinfo"); 971 default: 972 errx(1, "getnameinfo: %s", gai_strerror(herr)); 973 } 974 } 975 976 if (timeout_connect(s, res->ai_addr, res->ai_addrlen) == 0) 977 break; 978 979 if (vflag) { 980 /* only print IP if there is something to report */ 981 if (nflag || ipaddr == NULL || 982 (strncmp(host, ipaddr, NI_MAXHOST) == 0)) 983 warn("connect to %s port %s (%s) failed", host, 984 port, uflag ? "udp" : "tcp"); 985 else 986 warn("connect to %s (%s) port %s (%s) failed", 987 host, ipaddr, port, uflag ? "udp" : "tcp"); 988 } 989 990 save_errno = errno; 991 close(s); 992 errno = save_errno; 993 s = -1; 994 } 995 996 freeaddrinfo(res0); 997 998 return s; 999 } 1000 1001 int 1002 timeout_connect(int s, const struct sockaddr *name, socklen_t namelen) 1003 { 1004 struct pollfd pfd; 1005 socklen_t optlen; 1006 int optval; 1007 int ret; 1008 1009 if ((ret = connect(s, name, namelen)) != 0 && errno == EINPROGRESS) { 1010 pfd.fd = s; 1011 pfd.events = POLLOUT; 1012 if ((ret = poll(&pfd, 1, timeout)) == 1) { 1013 optlen = sizeof(optval); 1014 if ((ret = getsockopt(s, SOL_SOCKET, SO_ERROR, 1015 &optval, &optlen)) == 0) { 1016 errno = optval; 1017 ret = optval == 0 ? 0 : -1; 1018 } 1019 } else if (ret == 0) { 1020 errno = ETIMEDOUT; 1021 ret = -1; 1022 } else 1023 err(1, "poll failed"); 1024 } 1025 1026 return ret; 1027 } 1028 1029 /* 1030 * local_listen() 1031 * Returns a socket listening on a local port, binds to specified source 1032 * address. Returns -1 on failure. 1033 */ 1034 int 1035 local_listen(const char *host, const char *port, struct addrinfo hints) 1036 { 1037 struct addrinfo *res, *res0; 1038 int s = -1, ret, x = 1, save_errno; 1039 int error; 1040 1041 /* Allow nodename to be null. */ 1042 hints.ai_flags |= AI_PASSIVE; 1043 1044 /* 1045 * In the case of binding to a wildcard address 1046 * default to binding to an ipv4 address. 1047 */ 1048 if (host == NULL && hints.ai_family == AF_UNSPEC) 1049 hints.ai_family = AF_INET; 1050 1051 if ((error = getaddrinfo(host, port, &hints, &res0))) 1052 errx(1, "getaddrinfo: %s", gai_strerror(error)); 1053 1054 for (res = res0; res; res = res->ai_next) { 1055 if ((s = socket(res->ai_family, res->ai_socktype, 1056 res->ai_protocol)) == -1) 1057 continue; 1058 1059 ret = setsockopt(s, SOL_SOCKET, SO_REUSEPORT, &x, sizeof(x)); 1060 if (ret == -1) 1061 err(1, NULL); 1062 1063 set_common_sockopts(s, res->ai_family); 1064 1065 if (bind(s, (struct sockaddr *)res->ai_addr, 1066 res->ai_addrlen) == 0) 1067 break; 1068 1069 save_errno = errno; 1070 close(s); 1071 errno = save_errno; 1072 s = -1; 1073 } 1074 1075 if (!uflag && s != -1) { 1076 if (listen(s, 1) == -1) 1077 err(1, "listen"); 1078 } 1079 if (vflag && s != -1) { 1080 struct sockaddr_storage ss; 1081 socklen_t len; 1082 1083 len = sizeof(ss); 1084 if (getsockname(s, (struct sockaddr *)&ss, &len) == -1) 1085 err(1, "getsockname"); 1086 report_sock(uflag ? "Bound" : "Listening", 1087 (struct sockaddr *)&ss, len, NULL); 1088 } 1089 1090 freeaddrinfo(res0); 1091 1092 return s; 1093 } 1094 1095 /* 1096 * readwrite() 1097 * Loop that polls on the network file descriptor and stdin. 1098 */ 1099 void 1100 readwrite(int net_fd, struct tls *tls_ctx) 1101 { 1102 struct pollfd pfd[4]; 1103 int stdin_fd = STDIN_FILENO; 1104 int stdout_fd = STDOUT_FILENO; 1105 unsigned char netinbuf[BUFSIZE]; 1106 size_t netinbufpos = 0; 1107 unsigned char stdinbuf[BUFSIZE]; 1108 size_t stdinbufpos = 0; 1109 int n, num_fds; 1110 ssize_t ret; 1111 1112 /* don't read from stdin if requested */ 1113 if (dflag) 1114 stdin_fd = -1; 1115 1116 /* stdin */ 1117 pfd[POLL_STDIN].fd = stdin_fd; 1118 pfd[POLL_STDIN].events = POLLIN; 1119 1120 /* network out */ 1121 pfd[POLL_NETOUT].fd = net_fd; 1122 pfd[POLL_NETOUT].events = 0; 1123 1124 /* network in */ 1125 pfd[POLL_NETIN].fd = net_fd; 1126 pfd[POLL_NETIN].events = POLLIN; 1127 1128 /* stdout */ 1129 pfd[POLL_STDOUT].fd = stdout_fd; 1130 pfd[POLL_STDOUT].events = 0; 1131 1132 while (1) { 1133 /* both inputs are gone, buffers are empty, we are done */ 1134 if (pfd[POLL_STDIN].fd == -1 && pfd[POLL_NETIN].fd == -1 && 1135 stdinbufpos == 0 && netinbufpos == 0) 1136 return; 1137 /* both outputs are gone, we can't continue */ 1138 if (pfd[POLL_NETOUT].fd == -1 && pfd[POLL_STDOUT].fd == -1) 1139 return; 1140 /* listen and net in gone, queues empty, done */ 1141 if (lflag && pfd[POLL_NETIN].fd == -1 && 1142 stdinbufpos == 0 && netinbufpos == 0) 1143 return; 1144 1145 /* help says -i is for "wait between lines sent". We read and 1146 * write arbitrary amounts of data, and we don't want to start 1147 * scanning for newlines, so this is as good as it gets */ 1148 if (iflag) 1149 sleep(iflag); 1150 1151 /* poll */ 1152 num_fds = poll(pfd, 4, timeout); 1153 1154 /* treat poll errors */ 1155 if (num_fds == -1) 1156 err(1, "polling error"); 1157 1158 /* timeout happened */ 1159 if (num_fds == 0) 1160 return; 1161 1162 /* treat socket error conditions */ 1163 for (n = 0; n < 4; n++) { 1164 if (pfd[n].revents & (POLLERR|POLLNVAL)) { 1165 pfd[n].fd = -1; 1166 } 1167 } 1168 /* reading is possible after HUP */ 1169 if (pfd[POLL_STDIN].events & POLLIN && 1170 pfd[POLL_STDIN].revents & POLLHUP && 1171 !(pfd[POLL_STDIN].revents & POLLIN)) 1172 pfd[POLL_STDIN].fd = -1; 1173 1174 if (pfd[POLL_NETIN].events & POLLIN && 1175 pfd[POLL_NETIN].revents & POLLHUP && 1176 !(pfd[POLL_NETIN].revents & POLLIN)) 1177 pfd[POLL_NETIN].fd = -1; 1178 1179 if (pfd[POLL_NETOUT].revents & POLLHUP) { 1180 if (Nflag) 1181 shutdown(pfd[POLL_NETOUT].fd, SHUT_WR); 1182 pfd[POLL_NETOUT].fd = -1; 1183 } 1184 /* if HUP, stop watching stdout */ 1185 if (pfd[POLL_STDOUT].revents & POLLHUP) 1186 pfd[POLL_STDOUT].fd = -1; 1187 /* if no net out, stop watching stdin */ 1188 if (pfd[POLL_NETOUT].fd == -1) 1189 pfd[POLL_STDIN].fd = -1; 1190 /* if no stdout, stop watching net in */ 1191 if (pfd[POLL_STDOUT].fd == -1) { 1192 if (pfd[POLL_NETIN].fd != -1) 1193 shutdown(pfd[POLL_NETIN].fd, SHUT_RD); 1194 pfd[POLL_NETIN].fd = -1; 1195 } 1196 1197 /* try to read from stdin */ 1198 if (pfd[POLL_STDIN].revents & POLLIN && stdinbufpos < BUFSIZE) { 1199 ret = fillbuf(pfd[POLL_STDIN].fd, stdinbuf, 1200 &stdinbufpos, NULL); 1201 if (ret == TLS_WANT_POLLIN) 1202 pfd[POLL_STDIN].events = POLLIN; 1203 else if (ret == TLS_WANT_POLLOUT) 1204 pfd[POLL_STDIN].events = POLLOUT; 1205 else if (ret == 0 || ret == -1) 1206 pfd[POLL_STDIN].fd = -1; 1207 /* read something - poll net out */ 1208 if (stdinbufpos > 0) 1209 pfd[POLL_NETOUT].events = POLLOUT; 1210 /* filled buffer - remove self from polling */ 1211 if (stdinbufpos == BUFSIZE) 1212 pfd[POLL_STDIN].events = 0; 1213 } 1214 /* try to write to network */ 1215 if (pfd[POLL_NETOUT].revents & POLLOUT && stdinbufpos > 0) { 1216 ret = drainbuf(pfd[POLL_NETOUT].fd, stdinbuf, 1217 &stdinbufpos, tls_ctx); 1218 if (ret == TLS_WANT_POLLIN) 1219 pfd[POLL_NETOUT].events = POLLIN; 1220 else if (ret == TLS_WANT_POLLOUT) 1221 pfd[POLL_NETOUT].events = POLLOUT; 1222 else if (ret == -1) 1223 pfd[POLL_NETOUT].fd = -1; 1224 /* buffer empty - remove self from polling */ 1225 if (stdinbufpos == 0) 1226 pfd[POLL_NETOUT].events = 0; 1227 /* buffer no longer full - poll stdin again */ 1228 if (stdinbufpos < BUFSIZE) 1229 pfd[POLL_STDIN].events = POLLIN; 1230 } 1231 /* try to read from network */ 1232 if (pfd[POLL_NETIN].revents & POLLIN && netinbufpos < BUFSIZE) { 1233 ret = fillbuf(pfd[POLL_NETIN].fd, netinbuf, 1234 &netinbufpos, tls_ctx); 1235 if (ret == TLS_WANT_POLLIN) 1236 pfd[POLL_NETIN].events = POLLIN; 1237 else if (ret == TLS_WANT_POLLOUT) 1238 pfd[POLL_NETIN].events = POLLOUT; 1239 else if (ret == -1) 1240 pfd[POLL_NETIN].fd = -1; 1241 /* eof on net in - remove from pfd */ 1242 if (ret == 0) { 1243 shutdown(pfd[POLL_NETIN].fd, SHUT_RD); 1244 pfd[POLL_NETIN].fd = -1; 1245 } 1246 if (recvlimit > 0 && ++recvcount >= recvlimit) { 1247 if (pfd[POLL_NETIN].fd != -1) 1248 shutdown(pfd[POLL_NETIN].fd, SHUT_RD); 1249 pfd[POLL_NETIN].fd = -1; 1250 pfd[POLL_STDIN].fd = -1; 1251 } 1252 /* read something - poll stdout */ 1253 if (netinbufpos > 0) 1254 pfd[POLL_STDOUT].events = POLLOUT; 1255 /* filled buffer - remove self from polling */ 1256 if (netinbufpos == BUFSIZE) 1257 pfd[POLL_NETIN].events = 0; 1258 /* handle telnet */ 1259 if (tflag) 1260 atelnet(pfd[POLL_NETIN].fd, netinbuf, 1261 netinbufpos); 1262 } 1263 /* try to write to stdout */ 1264 if (pfd[POLL_STDOUT].revents & POLLOUT && netinbufpos > 0) { 1265 ret = drainbuf(pfd[POLL_STDOUT].fd, netinbuf, 1266 &netinbufpos, NULL); 1267 if (ret == TLS_WANT_POLLIN) 1268 pfd[POLL_STDOUT].events = POLLIN; 1269 else if (ret == TLS_WANT_POLLOUT) 1270 pfd[POLL_STDOUT].events = POLLOUT; 1271 else if (ret == -1) 1272 pfd[POLL_STDOUT].fd = -1; 1273 /* buffer empty - remove self from polling */ 1274 if (netinbufpos == 0) 1275 pfd[POLL_STDOUT].events = 0; 1276 /* buffer no longer full - poll net in again */ 1277 if (netinbufpos < BUFSIZE) 1278 pfd[POLL_NETIN].events = POLLIN; 1279 } 1280 1281 /* stdin gone and queue empty? */ 1282 if (pfd[POLL_STDIN].fd == -1 && stdinbufpos == 0) { 1283 if (pfd[POLL_NETOUT].fd != -1 && Nflag) 1284 shutdown(pfd[POLL_NETOUT].fd, SHUT_WR); 1285 pfd[POLL_NETOUT].fd = -1; 1286 } 1287 /* net in gone and queue empty? */ 1288 if (pfd[POLL_NETIN].fd == -1 && netinbufpos == 0) { 1289 pfd[POLL_STDOUT].fd = -1; 1290 } 1291 } 1292 } 1293 1294 ssize_t 1295 drainbuf(int fd, unsigned char *buf, size_t *bufpos, struct tls *tls) 1296 { 1297 ssize_t n; 1298 ssize_t adjust; 1299 1300 if (tls) { 1301 n = tls_write(tls, buf, *bufpos); 1302 if (n == -1) 1303 errx(1, "tls write failed (%s)", tls_error(tls)); 1304 } else { 1305 n = write(fd, buf, *bufpos); 1306 /* don't treat EAGAIN, EINTR as error */ 1307 if (n == -1 && (errno == EAGAIN || errno == EINTR)) 1308 n = TLS_WANT_POLLOUT; 1309 } 1310 if (n <= 0) 1311 return n; 1312 /* adjust buffer */ 1313 adjust = *bufpos - n; 1314 if (adjust > 0) 1315 memmove(buf, buf + n, adjust); 1316 *bufpos -= n; 1317 return n; 1318 } 1319 1320 ssize_t 1321 fillbuf(int fd, unsigned char *buf, size_t *bufpos, struct tls *tls) 1322 { 1323 size_t num = BUFSIZE - *bufpos; 1324 ssize_t n; 1325 1326 if (tls) { 1327 n = tls_read(tls, buf + *bufpos, num); 1328 if (n == -1) 1329 errx(1, "tls read failed (%s)", tls_error(tls)); 1330 } else { 1331 n = read(fd, buf + *bufpos, num); 1332 /* don't treat EAGAIN, EINTR as error */ 1333 if (n == -1 && (errno == EAGAIN || errno == EINTR)) 1334 n = TLS_WANT_POLLIN; 1335 } 1336 if (n <= 0) 1337 return n; 1338 *bufpos += n; 1339 return n; 1340 } 1341 1342 /* 1343 * fdpass() 1344 * Pass the connected file descriptor to stdout and exit. 1345 */ 1346 void 1347 fdpass(int nfd) 1348 { 1349 struct msghdr mh; 1350 union { 1351 struct cmsghdr hdr; 1352 char buf[CMSG_SPACE(sizeof(int))]; 1353 } cmsgbuf; 1354 struct cmsghdr *cmsg; 1355 struct iovec iov; 1356 char c = '\0'; 1357 ssize_t r; 1358 struct pollfd pfd; 1359 1360 /* Avoid obvious stupidity */ 1361 if (isatty(STDOUT_FILENO)) 1362 errx(1, "Cannot pass file descriptor to tty"); 1363 1364 memset(&mh, 0, sizeof(mh)); 1365 memset(&cmsgbuf, 0, sizeof(cmsgbuf)); 1366 memset(&iov, 0, sizeof(iov)); 1367 1368 mh.msg_control = (caddr_t)&cmsgbuf.buf; 1369 mh.msg_controllen = sizeof(cmsgbuf.buf); 1370 cmsg = CMSG_FIRSTHDR(&mh); 1371 cmsg->cmsg_len = CMSG_LEN(sizeof(int)); 1372 cmsg->cmsg_level = SOL_SOCKET; 1373 cmsg->cmsg_type = SCM_RIGHTS; 1374 *(int *)CMSG_DATA(cmsg) = nfd; 1375 1376 iov.iov_base = &c; 1377 iov.iov_len = 1; 1378 mh.msg_iov = &iov; 1379 mh.msg_iovlen = 1; 1380 1381 memset(&pfd, 0, sizeof(pfd)); 1382 pfd.fd = STDOUT_FILENO; 1383 pfd.events = POLLOUT; 1384 for (;;) { 1385 r = sendmsg(STDOUT_FILENO, &mh, 0); 1386 if (r == -1) { 1387 if (errno == EAGAIN || errno == EINTR) { 1388 if (poll(&pfd, 1, -1) == -1) 1389 err(1, "poll"); 1390 continue; 1391 } 1392 err(1, "sendmsg"); 1393 } else if (r != 1) 1394 errx(1, "sendmsg: unexpected return value %zd", r); 1395 else 1396 break; 1397 } 1398 exit(0); 1399 } 1400 1401 /* Deal with RFC 854 WILL/WONT DO/DONT negotiation. */ 1402 void 1403 atelnet(int nfd, unsigned char *buf, unsigned int size) 1404 { 1405 unsigned char *p, *end; 1406 unsigned char obuf[4]; 1407 1408 if (size < 3) 1409 return; 1410 end = buf + size - 2; 1411 1412 for (p = buf; p < end; p++) { 1413 if (*p != IAC) 1414 continue; 1415 1416 obuf[0] = IAC; 1417 p++; 1418 if ((*p == WILL) || (*p == WONT)) 1419 obuf[1] = DONT; 1420 else if ((*p == DO) || (*p == DONT)) 1421 obuf[1] = WONT; 1422 else 1423 continue; 1424 1425 p++; 1426 obuf[2] = *p; 1427 if (atomicio(vwrite, nfd, obuf, 3) != 3) 1428 warn("Write Error!"); 1429 } 1430 } 1431 1432 int 1433 strtoport(char *portstr, int udp) 1434 { 1435 struct servent *entry; 1436 const char *errstr; 1437 char *proto; 1438 int port = -1; 1439 1440 proto = udp ? "udp" : "tcp"; 1441 1442 port = strtonum(portstr, 1, PORT_MAX, &errstr); 1443 if (errstr == NULL) 1444 return port; 1445 if (errno != EINVAL) 1446 errx(1, "port number %s: %s", errstr, portstr); 1447 if ((entry = getservbyname(portstr, proto)) == NULL) 1448 errx(1, "service \"%s\" unknown", portstr); 1449 return ntohs(entry->s_port); 1450 } 1451 1452 /* 1453 * build_ports() 1454 * Build an array of ports in portlist[], listing each port 1455 * that we should try to connect to. 1456 */ 1457 void 1458 build_ports(char *p) 1459 { 1460 char *n; 1461 int hi, lo, cp; 1462 int x = 0; 1463 1464 if (isdigit((unsigned char)*p) && (n = strchr(p, '-')) != NULL) { 1465 *n = '\0'; 1466 n++; 1467 1468 /* Make sure the ports are in order: lowest->highest. */ 1469 hi = strtoport(n, uflag); 1470 lo = strtoport(p, uflag); 1471 if (lo > hi) { 1472 cp = hi; 1473 hi = lo; 1474 lo = cp; 1475 } 1476 1477 /* 1478 * Initialize portlist with a random permutation. Based on 1479 * Knuth, as in ip_randomid() in sys/netinet/ip_id.c. 1480 */ 1481 if (rflag) { 1482 for (x = 0; x <= hi - lo; x++) { 1483 cp = arc4random_uniform(x + 1); 1484 portlist[x] = portlist[cp]; 1485 if (asprintf(&portlist[cp], "%d", x + lo) == -1) 1486 err(1, "asprintf"); 1487 } 1488 } else { /* Load ports sequentially. */ 1489 for (cp = lo; cp <= hi; cp++) { 1490 if (asprintf(&portlist[x], "%d", cp) == -1) 1491 err(1, "asprintf"); 1492 x++; 1493 } 1494 } 1495 } else { 1496 char *tmp; 1497 1498 hi = strtoport(p, uflag); 1499 if (asprintf(&tmp, "%d", hi) != -1) 1500 portlist[0] = tmp; 1501 else 1502 err(1, NULL); 1503 } 1504 } 1505 1506 /* 1507 * udptest() 1508 * Do a few writes to see if the UDP port is there. 1509 * Fails once PF state table is full. 1510 */ 1511 int 1512 udptest(int s) 1513 { 1514 int i, ret; 1515 1516 /* Only write to the socket in scan mode or interactive mode. */ 1517 if (!zflag && !isatty(STDIN_FILENO)) 1518 return 0; 1519 1520 for (i = 0; i <= 3; i++) { 1521 if (write(s, "X", 1) == 1) 1522 ret = 1; 1523 else 1524 ret = -1; 1525 } 1526 return ret; 1527 } 1528 1529 void 1530 connection_info(const char *host, const char *port, const char *proto, 1531 const char *ipaddr) 1532 { 1533 struct servent *sv; 1534 char *service = "*"; 1535 1536 /* Look up service name unless -n. */ 1537 if (!nflag) { 1538 sv = getservbyport(ntohs(atoi(port)), proto); 1539 if (sv != NULL) 1540 service = sv->s_name; 1541 } 1542 1543 fprintf(stderr, "Connection to %s", host); 1544 1545 /* 1546 * if we aren't connecting thru a proxy and 1547 * there is something to report, print IP 1548 */ 1549 if (!nflag && !xflag && strcmp(host, ipaddr) != 0) 1550 fprintf(stderr, " (%s)", ipaddr); 1551 1552 fprintf(stderr, " %s port [%s/%s] succeeded!\n", port, proto, service); 1553 } 1554 1555 void 1556 set_common_sockopts(int s, int af) 1557 { 1558 int x = 1; 1559 1560 if (Sflag) { 1561 if (setsockopt(s, IPPROTO_TCP, TCP_MD5SIG, 1562 &x, sizeof(x)) == -1) 1563 err(1, NULL); 1564 } 1565 if (Dflag) { 1566 if (setsockopt(s, SOL_SOCKET, SO_DEBUG, 1567 &x, sizeof(x)) == -1) 1568 err(1, NULL); 1569 } 1570 if (Tflag != -1) { 1571 if (af == AF_INET && setsockopt(s, IPPROTO_IP, 1572 IP_TOS, &Tflag, sizeof(Tflag)) == -1) 1573 err(1, "set IP ToS"); 1574 1575 else if (af == AF_INET6 && setsockopt(s, IPPROTO_IPV6, 1576 IPV6_TCLASS, &Tflag, sizeof(Tflag)) == -1) 1577 err(1, "set IPv6 traffic class"); 1578 } 1579 if (Iflag) { 1580 if (setsockopt(s, SOL_SOCKET, SO_RCVBUF, 1581 &Iflag, sizeof(Iflag)) == -1) 1582 err(1, "set TCP receive buffer size"); 1583 } 1584 if (Oflag) { 1585 if (setsockopt(s, SOL_SOCKET, SO_SNDBUF, 1586 &Oflag, sizeof(Oflag)) == -1) 1587 err(1, "set TCP send buffer size"); 1588 } 1589 1590 if (ttl != -1) { 1591 if (af == AF_INET && setsockopt(s, IPPROTO_IP, 1592 IP_TTL, &ttl, sizeof(ttl))) 1593 err(1, "set IP TTL"); 1594 1595 else if (af == AF_INET6 && setsockopt(s, IPPROTO_IPV6, 1596 IPV6_UNICAST_HOPS, &ttl, sizeof(ttl))) 1597 err(1, "set IPv6 unicast hops"); 1598 } 1599 1600 if (minttl != -1) { 1601 if (af == AF_INET && setsockopt(s, IPPROTO_IP, 1602 IP_MINTTL, &minttl, sizeof(minttl))) 1603 err(1, "set IP min TTL"); 1604 1605 else if (af == AF_INET6 && setsockopt(s, IPPROTO_IPV6, 1606 IPV6_MINHOPCOUNT, &minttl, sizeof(minttl))) 1607 err(1, "set IPv6 min hop count"); 1608 } 1609 } 1610 1611 int 1612 process_tos_opt(char *s, int *val) 1613 { 1614 /* DiffServ Codepoints and other TOS mappings */ 1615 const struct toskeywords { 1616 const char *keyword; 1617 int val; 1618 } *t, toskeywords[] = { 1619 { "af11", IPTOS_DSCP_AF11 }, 1620 { "af12", IPTOS_DSCP_AF12 }, 1621 { "af13", IPTOS_DSCP_AF13 }, 1622 { "af21", IPTOS_DSCP_AF21 }, 1623 { "af22", IPTOS_DSCP_AF22 }, 1624 { "af23", IPTOS_DSCP_AF23 }, 1625 { "af31", IPTOS_DSCP_AF31 }, 1626 { "af32", IPTOS_DSCP_AF32 }, 1627 { "af33", IPTOS_DSCP_AF33 }, 1628 { "af41", IPTOS_DSCP_AF41 }, 1629 { "af42", IPTOS_DSCP_AF42 }, 1630 { "af43", IPTOS_DSCP_AF43 }, 1631 { "critical", IPTOS_PREC_CRITIC_ECP }, 1632 { "cs0", IPTOS_DSCP_CS0 }, 1633 { "cs1", IPTOS_DSCP_CS1 }, 1634 { "cs2", IPTOS_DSCP_CS2 }, 1635 { "cs3", IPTOS_DSCP_CS3 }, 1636 { "cs4", IPTOS_DSCP_CS4 }, 1637 { "cs5", IPTOS_DSCP_CS5 }, 1638 { "cs6", IPTOS_DSCP_CS6 }, 1639 { "cs7", IPTOS_DSCP_CS7 }, 1640 { "ef", IPTOS_DSCP_EF }, 1641 { "inetcontrol", IPTOS_PREC_INTERNETCONTROL }, 1642 { "lowdelay", IPTOS_LOWDELAY }, 1643 { "netcontrol", IPTOS_PREC_NETCONTROL }, 1644 { "reliability", IPTOS_RELIABILITY }, 1645 { "throughput", IPTOS_THROUGHPUT }, 1646 { NULL, -1 }, 1647 }; 1648 1649 for (t = toskeywords; t->keyword != NULL; t++) { 1650 if (strcmp(s, t->keyword) == 0) { 1651 *val = t->val; 1652 return 1; 1653 } 1654 } 1655 1656 return 0; 1657 } 1658 1659 int 1660 process_tls_opt(char *s, int *flags) 1661 { 1662 size_t len; 1663 char *v; 1664 1665 const struct tlskeywords { 1666 const char *keyword; 1667 int flag; 1668 char **value; 1669 } *t, tlskeywords[] = { 1670 { "ciphers", -1, &tls_ciphers }, 1671 { "clientcert", TLS_CCERT, NULL }, 1672 { "muststaple", TLS_MUSTSTAPLE, NULL }, 1673 { "noverify", TLS_NOVERIFY, NULL }, 1674 { "noname", TLS_NONAME, NULL }, 1675 { "protocols", -1, &tls_protocols }, 1676 { NULL, -1, NULL }, 1677 }; 1678 1679 len = strlen(s); 1680 if ((v = strchr(s, '=')) != NULL) { 1681 len = v - s; 1682 v++; 1683 } 1684 1685 for (t = tlskeywords; t->keyword != NULL; t++) { 1686 if (strlen(t->keyword) == len && 1687 strncmp(s, t->keyword, len) == 0) { 1688 if (t->value != NULL) { 1689 if (v == NULL) 1690 errx(1, "invalid tls value `%s'", s); 1691 *t->value = v; 1692 } else { 1693 *flags |= t->flag; 1694 } 1695 return 1; 1696 } 1697 } 1698 return 0; 1699 } 1700 1701 void 1702 save_peer_cert(struct tls *tls_ctx, FILE *fp) 1703 { 1704 const char *pem; 1705 size_t plen; 1706 1707 if ((pem = tls_peer_cert_chain_pem(tls_ctx, &plen)) == NULL) 1708 errx(1, "Can't get peer certificate"); 1709 if (fprintf(fp, "%.*s", (int)plen, pem) < 0) 1710 err(1, "unable to save peer cert"); 1711 if (fflush(fp) != 0) 1712 err(1, "unable to flush peer cert"); 1713 } 1714 1715 void 1716 report_tls(struct tls *tls_ctx, char *host) 1717 { 1718 time_t t; 1719 const char *ocsp_url; 1720 1721 fprintf(stderr, "TLS handshake negotiated %s/%s with host %s\n", 1722 tls_conn_version(tls_ctx), tls_conn_cipher(tls_ctx), host); 1723 fprintf(stderr, "Peer name: %s\n", 1724 tls_expectname ? tls_expectname : host); 1725 if (tls_peer_cert_subject(tls_ctx)) 1726 fprintf(stderr, "Subject: %s\n", 1727 tls_peer_cert_subject(tls_ctx)); 1728 if (tls_peer_cert_issuer(tls_ctx)) 1729 fprintf(stderr, "Issuer: %s\n", 1730 tls_peer_cert_issuer(tls_ctx)); 1731 if ((t = tls_peer_cert_notbefore(tls_ctx)) != -1) 1732 fprintf(stderr, "Valid From: %s", ctime(&t)); 1733 if ((t = tls_peer_cert_notafter(tls_ctx)) != -1) 1734 fprintf(stderr, "Valid Until: %s", ctime(&t)); 1735 if (tls_peer_cert_hash(tls_ctx)) 1736 fprintf(stderr, "Cert Hash: %s\n", 1737 tls_peer_cert_hash(tls_ctx)); 1738 ocsp_url = tls_peer_ocsp_url(tls_ctx); 1739 if (ocsp_url != NULL) 1740 fprintf(stderr, "OCSP URL: %s\n", ocsp_url); 1741 switch (tls_peer_ocsp_response_status(tls_ctx)) { 1742 case TLS_OCSP_RESPONSE_SUCCESSFUL: 1743 fprintf(stderr, "OCSP Stapling: %s\n", 1744 tls_peer_ocsp_result(tls_ctx) == NULL ? "" : 1745 tls_peer_ocsp_result(tls_ctx)); 1746 fprintf(stderr, 1747 " response_status=%d cert_status=%d crl_reason=%d\n", 1748 tls_peer_ocsp_response_status(tls_ctx), 1749 tls_peer_ocsp_cert_status(tls_ctx), 1750 tls_peer_ocsp_crl_reason(tls_ctx)); 1751 t = tls_peer_ocsp_this_update(tls_ctx); 1752 fprintf(stderr, " this update: %s", 1753 t != -1 ? ctime(&t) : "\n"); 1754 t = tls_peer_ocsp_next_update(tls_ctx); 1755 fprintf(stderr, " next update: %s", 1756 t != -1 ? ctime(&t) : "\n"); 1757 t = tls_peer_ocsp_revocation_time(tls_ctx); 1758 fprintf(stderr, " revocation: %s", 1759 t != -1 ? ctime(&t) : "\n"); 1760 break; 1761 case -1: 1762 break; 1763 default: 1764 fprintf(stderr, 1765 "OCSP Stapling: failure - response_status %d (%s)\n", 1766 tls_peer_ocsp_response_status(tls_ctx), 1767 tls_peer_ocsp_result(tls_ctx) == NULL ? "" : 1768 tls_peer_ocsp_result(tls_ctx)); 1769 break; 1770 } 1771 } 1772 1773 void 1774 report_sock(const char *msg, const struct sockaddr *sa, socklen_t salen, 1775 char *path) 1776 { 1777 char host[NI_MAXHOST], port[NI_MAXSERV]; 1778 int herr; 1779 int flags = NI_NUMERICSERV; 1780 1781 if (path != NULL) { 1782 fprintf(stderr, "%s on %s\n", msg, path); 1783 return; 1784 } 1785 1786 if (nflag) 1787 flags |= NI_NUMERICHOST; 1788 1789 herr = getnameinfo(sa, salen, host, sizeof(host), port, sizeof(port), 1790 flags); 1791 switch (herr) { 1792 case 0: 1793 break; 1794 case EAI_SYSTEM: 1795 err(1, "getnameinfo"); 1796 default: 1797 errx(1, "getnameinfo: %s", gai_strerror(herr)); 1798 } 1799 1800 fprintf(stderr, "%s on %s %s\n", msg, host, port); 1801 } 1802 1803 void 1804 help(void) 1805 { 1806 usage(0); 1807 fprintf(stderr, "\tCommand Summary:\n\ 1808 \t-4 Use IPv4\n\ 1809 \t-6 Use IPv6\n\ 1810 \t-C certfile Public key file\n\ 1811 \t-c Use TLS\n\ 1812 \t-D Enable the debug socket option\n\ 1813 \t-d Detach from stdin\n\ 1814 \t-e name\t Required name in peer certificate\n\ 1815 \t-F Pass socket fd\n\ 1816 \t-H hash\t Hash string of peer certificate\n\ 1817 \t-h This help text\n\ 1818 \t-I length TCP receive buffer length\n\ 1819 \t-i interval Delay interval for lines sent, ports scanned\n\ 1820 \t-K keyfile Private key file\n\ 1821 \t-k Keep inbound sockets open for multiple connects\n\ 1822 \t-l Listen mode, for inbound connects\n\ 1823 \t-M ttl Outgoing TTL / Hop Limit\n\ 1824 \t-m minttl Minimum incoming TTL / Hop Limit\n\ 1825 \t-N Shutdown the network socket after EOF on stdin\n\ 1826 \t-n Suppress name/port resolutions\n\ 1827 \t-O length TCP send buffer length\n\ 1828 \t-o staplefile Staple file\n\ 1829 \t-P proxyuser\tUsername for proxy authentication\n\ 1830 \t-p port\t Specify local port for remote connects\n\ 1831 \t-R CAfile CA bundle\n\ 1832 \t-r Randomize remote ports\n\ 1833 \t-S Enable the TCP MD5 signature option\n\ 1834 \t-s sourceaddr Local source address\n\ 1835 \t-T keyword TOS value or TLS options\n\ 1836 \t-t Answer TELNET negotiation\n\ 1837 \t-U Use UNIX domain socket\n\ 1838 \t-u UDP mode\n\ 1839 \t-V rtable Specify alternate routing table\n\ 1840 \t-v Verbose\n\ 1841 \t-W recvlimit Terminate after receiving a number of packets\n\ 1842 \t-w timeout Timeout for connects and final net reads\n\ 1843 \t-X proto Proxy protocol: \"4\", \"5\" (SOCKS) or \"connect\"\n\ 1844 \t-x addr[:port]\tSpecify proxy address and port\n\ 1845 \t-Z Peer certificate file\n\ 1846 \t-z Zero-I/O mode [used for scanning]\n\ 1847 Port numbers can be individual or ranges: lo-hi [inclusive]\n"); 1848 exit(1); 1849 } 1850 1851 void 1852 usage(int ret) 1853 { 1854 fprintf(stderr, 1855 "usage: nc [-46cDdFhklNnrStUuvz] [-C certfile] [-e name] " 1856 "[-H hash] [-I length]\n" 1857 "\t [-i interval] [-K keyfile] [-M ttl] [-m minttl] [-O length]\n" 1858 "\t [-o staplefile] [-P proxy_username] [-p source_port] " 1859 "[-R CAfile]\n" 1860 "\t [-s sourceaddr] [-T keyword] [-V rtable] [-W recvlimit] " 1861 "[-w timeout]\n" 1862 "\t [-X proxy_protocol] [-x proxy_address[:port]] " 1863 "[-Z peercertfile]\n" 1864 "\t [destination] [port]\n"); 1865 if (ret) 1866 exit(1); 1867 } 1868