1 /* $OpenBSD: netcat.c,v 1.190 2018/03/19 16:35:29 jsing Exp $ */ 2 /* 3 * Copyright (c) 2001 Eric Jackson <ericj@monkey.org> 4 * Copyright (c) 2015 Bob Beck. All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. The name of the author may not be used to endorse or promote products 16 * derived from this software without specific prior written permission. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 19 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 20 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 21 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 22 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 23 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 24 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 25 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 26 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 27 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 28 */ 29 30 /* 31 * Re-written nc(1) for OpenBSD. Original implementation by 32 * *Hobbit* <hobbit@avian.org>. 33 */ 34 35 #include <sys/types.h> 36 #include <sys/socket.h> 37 #include <sys/uio.h> 38 #include <sys/un.h> 39 40 #include <netinet/in.h> 41 #include <netinet/tcp.h> 42 #include <netinet/ip.h> 43 #include <arpa/telnet.h> 44 45 #include <err.h> 46 #include <errno.h> 47 #include <limits.h> 48 #include <netdb.h> 49 #include <poll.h> 50 #include <signal.h> 51 #include <stdarg.h> 52 #include <stdio.h> 53 #include <stdlib.h> 54 #include <string.h> 55 #include <time.h> 56 #include <tls.h> 57 #include <unistd.h> 58 59 #include "atomicio.h" 60 61 #define PORT_MAX 65535 62 #define UNIX_DG_TMP_SOCKET_SIZE 19 63 64 #define POLL_STDIN 0 65 #define POLL_NETOUT 1 66 #define POLL_NETIN 2 67 #define POLL_STDOUT 3 68 #define BUFSIZE 16384 69 #define DEFAULT_CA_FILE "/etc/ssl/cert.pem" 70 71 #define TLS_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 char *Cflag; /* Public cert file */ 102 char *Kflag; /* Private key file */ 103 char *oflag; /* OCSP stapling file */ 104 char *Rflag = DEFAULT_CA_FILE; /* Root CA file */ 105 int tls_cachanged; /* Using non-default CA file */ 106 int TLSopt; /* TLS options */ 107 char *tls_expectname; /* required name in peer cert */ 108 char *tls_expecthash; /* required hash of peer cert */ 109 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(char *, char *, struct addrinfo); 126 void readwrite(int, struct tls *); 127 void fdpass(int nfd) __attribute__((noreturn)); 128 int remote_connect(const char *, const char *, struct addrinfo); 129 int timeout_tls(int, struct tls *, int (*)(struct tls *)); 130 int timeout_connect(int, const struct sockaddr *, socklen_t); 131 int socks_connect(const char *, const char *, struct addrinfo, 132 const char *, const char *, struct addrinfo, int, const char *); 133 int udptest(int); 134 int unix_bind(char *, int); 135 int unix_connect(char *); 136 int unix_listen(char *); 137 void set_common_sockopts(int, int); 138 int 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_connect(const struct sockaddr *, socklen_t, char *); 142 void report_tls(struct tls *tls_ctx, char * host); 143 void usage(int); 144 ssize_t drainbuf(int, unsigned char *, size_t *, struct tls *); 145 ssize_t fillbuf(int, unsigned char *, size_t *, struct tls *); 146 void tls_setup_client(struct tls *, int, char *); 147 struct tls *tls_setup_server(struct tls *, int, char *); 148 149 int 150 main(int argc, char *argv[]) 151 { 152 int ch, s = -1, ret, socksv; 153 char *host, *uport; 154 struct addrinfo hints; 155 struct servent *sv; 156 socklen_t len; 157 struct sockaddr_storage cliaddr; 158 char *proxy = NULL, *proxyport = NULL; 159 const char *errstr; 160 struct addrinfo proxyhints; 161 char unix_dg_tmp_socket_buf[UNIX_DG_TMP_SOCKET_SIZE]; 162 struct tls_config *tls_cfg = NULL; 163 struct tls *tls_ctx = NULL; 164 uint32_t protocols; 165 166 ret = 1; 167 socksv = 5; 168 host = NULL; 169 uport = NULL; 170 sv = NULL; 171 172 signal(SIGPIPE, SIG_IGN); 173 174 while ((ch = getopt(argc, argv, 175 "46C:cDde:FH:hI:i:K:klM:m:NnO:o:P:p:R:rSs:T:tUuV:vW:w:X:x:Z:z")) 176 != -1) { 177 switch (ch) { 178 case '4': 179 family = AF_INET; 180 break; 181 case '6': 182 family = AF_INET6; 183 break; 184 case 'U': 185 family = AF_UNIX; 186 break; 187 case 'X': 188 if (strcasecmp(optarg, "connect") == 0) 189 socksv = -1; /* HTTP proxy CONNECT */ 190 else if (strcmp(optarg, "4") == 0) 191 socksv = 4; /* SOCKS v.4 */ 192 else if (strcmp(optarg, "5") == 0) 193 socksv = 5; /* SOCKS v.5 */ 194 else 195 errx(1, "unsupported proxy protocol"); 196 break; 197 case 'C': 198 Cflag = optarg; 199 break; 200 case 'c': 201 usetls = 1; 202 break; 203 case 'd': 204 dflag = 1; 205 break; 206 case 'e': 207 tls_expectname = optarg; 208 break; 209 case 'F': 210 Fflag = 1; 211 break; 212 case 'H': 213 tls_expecthash = optarg; 214 break; 215 case 'h': 216 help(); 217 break; 218 case 'i': 219 iflag = strtonum(optarg, 0, UINT_MAX, &errstr); 220 if (errstr) 221 errx(1, "interval %s: %s", errstr, optarg); 222 break; 223 case 'K': 224 Kflag = optarg; 225 break; 226 case 'k': 227 kflag = 1; 228 break; 229 case 'l': 230 lflag = 1; 231 break; 232 case 'M': 233 ttl = strtonum(optarg, 0, 255, &errstr); 234 if (errstr) 235 errx(1, "ttl is %s", errstr); 236 break; 237 case 'm': 238 minttl = strtonum(optarg, 0, 255, &errstr); 239 if (errstr) 240 errx(1, "minttl is %s", errstr); 241 break; 242 case 'N': 243 Nflag = 1; 244 break; 245 case 'n': 246 nflag = 1; 247 break; 248 case 'P': 249 Pflag = optarg; 250 break; 251 case 'p': 252 pflag = optarg; 253 break; 254 case 'R': 255 tls_cachanged = 1; 256 Rflag = optarg; 257 break; 258 case 'r': 259 rflag = 1; 260 break; 261 case 's': 262 sflag = optarg; 263 break; 264 case 't': 265 tflag = 1; 266 break; 267 case 'u': 268 uflag = 1; 269 break; 270 case 'V': 271 rtableid = (int)strtonum(optarg, 0, 272 RT_TABLEID_MAX, &errstr); 273 if (errstr) 274 errx(1, "rtable %s: %s", errstr, optarg); 275 break; 276 case 'v': 277 vflag = 1; 278 break; 279 case 'W': 280 recvlimit = strtonum(optarg, 1, INT_MAX, &errstr); 281 if (errstr) 282 errx(1, "receive limit %s: %s", errstr, optarg); 283 break; 284 case 'w': 285 timeout = strtonum(optarg, 0, INT_MAX / 1000, &errstr); 286 if (errstr) 287 errx(1, "timeout %s: %s", errstr, optarg); 288 timeout *= 1000; 289 break; 290 case 'x': 291 xflag = 1; 292 if ((proxy = strdup(optarg)) == NULL) 293 err(1, NULL); 294 break; 295 case 'Z': 296 if (strcmp(optarg, "-") == 0) 297 Zflag = stderr; 298 else if ((Zflag = fopen(optarg, "w")) == NULL) 299 err(1, "can't open %s", optarg); 300 break; 301 case 'z': 302 zflag = 1; 303 break; 304 case 'D': 305 Dflag = 1; 306 break; 307 case 'I': 308 Iflag = strtonum(optarg, 1, 65536 << 14, &errstr); 309 if (errstr != NULL) 310 errx(1, "TCP receive window %s: %s", 311 errstr, optarg); 312 break; 313 case 'O': 314 Oflag = strtonum(optarg, 1, 65536 << 14, &errstr); 315 if (errstr != NULL) 316 errx(1, "TCP send window %s: %s", 317 errstr, optarg); 318 break; 319 case 'o': 320 oflag = optarg; 321 break; 322 case 'S': 323 Sflag = 1; 324 break; 325 case 'T': 326 errstr = NULL; 327 errno = 0; 328 if (process_tls_opt(optarg, &TLSopt)) 329 break; 330 if (process_tos_opt(optarg, &Tflag)) 331 break; 332 if (strlen(optarg) > 1 && optarg[0] == '0' && 333 optarg[1] == 'x') 334 Tflag = (int)strtol(optarg, NULL, 16); 335 else 336 Tflag = (int)strtonum(optarg, 0, 255, 337 &errstr); 338 if (Tflag < 0 || Tflag > 255 || errstr || errno) 339 errx(1, "illegal tos/tls value %s", optarg); 340 break; 341 default: 342 usage(1); 343 } 344 } 345 argc -= optind; 346 argv += optind; 347 348 if (rtableid >= 0) 349 if (setrtable(rtableid) == -1) 350 err(1, "setrtable"); 351 352 if (family == AF_UNIX) { 353 if (pledge("stdio rpath wpath cpath tmppath unix", NULL) == -1) 354 err(1, "pledge"); 355 } else if (Fflag && Pflag) { 356 if (pledge("stdio inet dns sendfd tty", NULL) == -1) 357 err(1, "pledge"); 358 } else if (Fflag) { 359 if (pledge("stdio inet dns sendfd", NULL) == -1) 360 err(1, "pledge"); 361 } else if (Pflag && usetls) { 362 if (pledge("stdio rpath inet dns tty", NULL) == -1) 363 err(1, "pledge"); 364 } else if (Pflag) { 365 if (pledge("stdio inet dns tty", NULL) == -1) 366 err(1, "pledge"); 367 } else if (usetls) { 368 if (pledge("stdio rpath inet dns", NULL) == -1) 369 err(1, "pledge"); 370 } else if (pledge("stdio inet dns", NULL) == -1) 371 err(1, "pledge"); 372 373 /* Cruft to make sure options are clean, and used properly. */ 374 if (argv[0] && !argv[1] && family == AF_UNIX) { 375 host = argv[0]; 376 uport = NULL; 377 } else if (argv[0] && !argv[1]) { 378 if (!lflag) 379 usage(1); 380 uport = argv[0]; 381 host = NULL; 382 } else if (argv[0] && argv[1]) { 383 host = argv[0]; 384 uport = argv[1]; 385 } else 386 usage(1); 387 388 if (lflag && sflag) 389 errx(1, "cannot use -s and -l"); 390 if (lflag && pflag) 391 errx(1, "cannot use -p and -l"); 392 if (lflag && zflag) 393 errx(1, "cannot use -z and -l"); 394 if (!lflag && kflag) 395 errx(1, "must use -l with -k"); 396 if (uflag && usetls) 397 errx(1, "cannot use -c and -u"); 398 if ((family == AF_UNIX) && usetls) 399 errx(1, "cannot use -c and -U"); 400 if ((family == AF_UNIX) && Fflag) 401 errx(1, "cannot use -F and -U"); 402 if (Fflag && usetls) 403 errx(1, "cannot use -c and -F"); 404 if (TLSopt && !usetls) 405 errx(1, "you must specify -c to use TLS options"); 406 if (Cflag && !usetls) 407 errx(1, "you must specify -c to use -C"); 408 if (Kflag && !usetls) 409 errx(1, "you must specify -c to use -K"); 410 if (Zflag && !usetls) 411 errx(1, "you must specify -c to use -Z"); 412 if (oflag && !Cflag) 413 errx(1, "you must specify -C to use -o"); 414 if (tls_cachanged && !usetls) 415 errx(1, "you must specify -c to use -R"); 416 if (tls_expecthash && !usetls) 417 errx(1, "you must specify -c to use -H"); 418 if (tls_expectname && !usetls) 419 errx(1, "you must specify -c to use -e"); 420 421 /* Get name of temporary socket for unix datagram client */ 422 if ((family == AF_UNIX) && uflag && !lflag) { 423 if (sflag) { 424 unix_dg_tmp_socket = sflag; 425 } else { 426 strlcpy(unix_dg_tmp_socket_buf, "/tmp/nc.XXXXXXXXXX", 427 UNIX_DG_TMP_SOCKET_SIZE); 428 if (mktemp(unix_dg_tmp_socket_buf) == NULL) 429 err(1, "mktemp"); 430 unix_dg_tmp_socket = unix_dg_tmp_socket_buf; 431 } 432 } 433 434 /* Initialize addrinfo structure. */ 435 if (family != AF_UNIX) { 436 memset(&hints, 0, sizeof(struct addrinfo)); 437 hints.ai_family = family; 438 hints.ai_socktype = uflag ? SOCK_DGRAM : SOCK_STREAM; 439 hints.ai_protocol = uflag ? IPPROTO_UDP : IPPROTO_TCP; 440 if (nflag) 441 hints.ai_flags |= AI_NUMERICHOST; 442 } 443 444 if (xflag) { 445 if (uflag) 446 errx(1, "no proxy support for UDP mode"); 447 448 if (lflag) 449 errx(1, "no proxy support for listen"); 450 451 if (family == AF_UNIX) 452 errx(1, "no proxy support for unix sockets"); 453 454 if (sflag) 455 errx(1, "no proxy support for local source address"); 456 457 if (*proxy == '[') { 458 ++proxy; 459 proxyport = strchr(proxy, ']'); 460 if (proxyport == NULL) 461 errx(1, "missing closing bracket in proxy"); 462 *proxyport++ = '\0'; 463 if (*proxyport == '\0') 464 /* Use default proxy port. */ 465 proxyport = NULL; 466 else { 467 if (*proxyport == ':') 468 ++proxyport; 469 else 470 errx(1, "garbage proxy port delimiter"); 471 } 472 } else { 473 proxyport = strrchr(proxy, ':'); 474 if (proxyport != NULL) 475 *proxyport++ = '\0'; 476 } 477 478 memset(&proxyhints, 0, sizeof(struct addrinfo)); 479 proxyhints.ai_family = family; 480 proxyhints.ai_socktype = SOCK_STREAM; 481 proxyhints.ai_protocol = IPPROTO_TCP; 482 if (nflag) 483 proxyhints.ai_flags |= AI_NUMERICHOST; 484 } 485 486 if (usetls) { 487 if ((tls_cfg = tls_config_new()) == NULL) 488 errx(1, "unable to allocate TLS config"); 489 if (Rflag && tls_config_set_ca_file(tls_cfg, Rflag) == -1) 490 errx(1, "%s", tls_config_error(tls_cfg)); 491 if (Cflag && tls_config_set_cert_file(tls_cfg, Cflag) == -1) 492 errx(1, "%s", tls_config_error(tls_cfg)); 493 if (Kflag && tls_config_set_key_file(tls_cfg, Kflag) == -1) 494 errx(1, "%s", tls_config_error(tls_cfg)); 495 if (oflag && tls_config_set_ocsp_staple_file(tls_cfg, oflag) == -1) 496 errx(1, "%s", tls_config_error(tls_cfg)); 497 if (tls_config_parse_protocols(&protocols, tls_protocols) == -1) 498 errx(1, "invalid TLS protocols `%s'", tls_protocols); 499 if (tls_config_set_protocols(tls_cfg, protocols) == -1) 500 errx(1, "%s", tls_config_error(tls_cfg)); 501 if (tls_config_set_ciphers(tls_cfg, tls_ciphers) == -1) 502 errx(1, "%s", tls_config_error(tls_cfg)); 503 if (!lflag && (TLSopt & TLS_CCERT)) 504 errx(1, "clientcert is only valid with -l"); 505 if (TLSopt & TLS_NONAME) 506 tls_config_insecure_noverifyname(tls_cfg); 507 if (TLSopt & TLS_NOVERIFY) { 508 if (tls_expecthash != NULL) 509 errx(1, "-H and -T noverify may not be used " 510 "together"); 511 tls_config_insecure_noverifycert(tls_cfg); 512 } 513 if (TLSopt & TLS_MUSTSTAPLE) 514 tls_config_ocsp_require_stapling(tls_cfg); 515 516 if (Pflag) { 517 if (pledge("stdio inet dns tty", NULL) == -1) 518 err(1, "pledge"); 519 } else if (pledge("stdio inet dns", NULL) == -1) 520 err(1, "pledge"); 521 } 522 if (lflag) { 523 struct tls *tls_cctx = NULL; 524 int connfd; 525 ret = 0; 526 527 if (family == AF_UNIX) { 528 if (uflag) 529 s = unix_bind(host, 0); 530 else 531 s = unix_listen(host); 532 } 533 534 if (usetls) { 535 tls_config_verify_client_optional(tls_cfg); 536 if ((tls_ctx = tls_server()) == NULL) 537 errx(1, "tls server creation failed"); 538 if (tls_configure(tls_ctx, tls_cfg) == -1) 539 errx(1, "tls configuration failed (%s)", 540 tls_error(tls_ctx)); 541 } 542 /* Allow only one connection at a time, but stay alive. */ 543 for (;;) { 544 if (family != AF_UNIX) 545 s = local_listen(host, uport, hints); 546 if (s < 0) 547 err(1, NULL); 548 if (uflag && kflag) { 549 /* 550 * For UDP and -k, don't connect the socket, 551 * let it receive datagrams from multiple 552 * socket pairs. 553 */ 554 readwrite(s, NULL); 555 } else if (uflag && !kflag) { 556 /* 557 * For UDP and not -k, we will use recvfrom() 558 * initially to wait for a caller, then use 559 * the regular functions to talk to the caller. 560 */ 561 int rv; 562 char buf[2048]; 563 struct sockaddr_storage z; 564 565 len = sizeof(z); 566 rv = recvfrom(s, buf, sizeof(buf), MSG_PEEK, 567 (struct sockaddr *)&z, &len); 568 if (rv < 0) 569 err(1, "recvfrom"); 570 571 rv = connect(s, (struct sockaddr *)&z, len); 572 if (rv < 0) 573 err(1, "connect"); 574 575 if (vflag) 576 report_connect((struct sockaddr *)&z, len, NULL); 577 578 readwrite(s, NULL); 579 } else { 580 len = sizeof(cliaddr); 581 connfd = accept4(s, (struct sockaddr *)&cliaddr, 582 &len, SOCK_NONBLOCK); 583 if (connfd == -1) { 584 /* For now, all errnos are fatal */ 585 err(1, "accept"); 586 } 587 if (vflag) 588 report_connect((struct sockaddr *)&cliaddr, len, 589 family == AF_UNIX ? host : NULL); 590 if ((usetls) && 591 (tls_cctx = tls_setup_server(tls_ctx, connfd, host))) 592 readwrite(connfd, tls_cctx); 593 if (!usetls) 594 readwrite(connfd, NULL); 595 if (tls_cctx) { 596 timeout_tls(s, tls_cctx, tls_close); 597 tls_free(tls_cctx); 598 tls_cctx = NULL; 599 } 600 close(connfd); 601 } 602 if (family != AF_UNIX) 603 close(s); 604 else if (uflag) { 605 if (connect(s, NULL, 0) < 0) 606 err(1, "connect"); 607 } 608 609 if (!kflag) 610 break; 611 } 612 } else if (family == AF_UNIX) { 613 ret = 0; 614 615 if ((s = unix_connect(host)) > 0) { 616 if (!zflag) 617 readwrite(s, NULL); 618 close(s); 619 } else 620 ret = 1; 621 622 if (uflag) 623 unlink(unix_dg_tmp_socket); 624 return ret; 625 626 } else { 627 int i = 0; 628 629 /* Construct the portlist[] array. */ 630 build_ports(uport); 631 632 /* Cycle through portlist, connecting to each port. */ 633 for (s = -1, i = 0; portlist[i] != NULL; i++) { 634 if (s != -1) 635 close(s); 636 637 if (usetls) { 638 if ((tls_ctx = tls_client()) == NULL) 639 errx(1, "tls client creation failed"); 640 if (tls_configure(tls_ctx, tls_cfg) == -1) 641 errx(1, "tls configuration failed (%s)", 642 tls_error(tls_ctx)); 643 } 644 if (xflag) 645 s = socks_connect(host, portlist[i], hints, 646 proxy, proxyport, proxyhints, socksv, 647 Pflag); 648 else 649 s = remote_connect(host, portlist[i], hints); 650 651 if (s == -1) 652 continue; 653 654 ret = 0; 655 if (vflag || zflag) { 656 /* For UDP, make sure we are connected. */ 657 if (uflag) { 658 if (udptest(s) == -1) { 659 ret = 1; 660 continue; 661 } 662 } 663 664 /* Don't look up port if -n. */ 665 if (nflag) 666 sv = NULL; 667 else { 668 sv = getservbyport( 669 ntohs(atoi(portlist[i])), 670 uflag ? "udp" : "tcp"); 671 } 672 673 fprintf(stderr, 674 "Connection to %s %s port [%s/%s] " 675 "succeeded!\n", host, portlist[i], 676 uflag ? "udp" : "tcp", 677 sv ? sv->s_name : "*"); 678 } 679 if (Fflag) 680 fdpass(s); 681 else { 682 if (usetls) 683 tls_setup_client(tls_ctx, s, host); 684 if (!zflag) 685 readwrite(s, tls_ctx); 686 if (tls_ctx) { 687 timeout_tls(s, tls_ctx, tls_close); 688 tls_free(tls_ctx); 689 tls_ctx = NULL; 690 } 691 } 692 } 693 } 694 695 if (s != -1) 696 close(s); 697 698 tls_config_free(tls_cfg); 699 700 return ret; 701 } 702 703 /* 704 * unix_bind() 705 * Returns a unix socket bound to the given path 706 */ 707 int 708 unix_bind(char *path, int flags) 709 { 710 struct sockaddr_un s_un; 711 int s, save_errno; 712 713 /* Create unix domain socket. */ 714 if ((s = socket(AF_UNIX, flags | (uflag ? SOCK_DGRAM : SOCK_STREAM), 715 0)) < 0) 716 return -1; 717 718 memset(&s_un, 0, sizeof(struct sockaddr_un)); 719 s_un.sun_family = AF_UNIX; 720 721 if (strlcpy(s_un.sun_path, path, sizeof(s_un.sun_path)) >= 722 sizeof(s_un.sun_path)) { 723 close(s); 724 errno = ENAMETOOLONG; 725 return -1; 726 } 727 728 if (bind(s, (struct sockaddr *)&s_un, sizeof(s_un)) < 0) { 729 save_errno = errno; 730 close(s); 731 errno = save_errno; 732 return -1; 733 } 734 735 return s; 736 } 737 738 int 739 timeout_tls(int s, struct tls *tls_ctx, int (*func)(struct tls *)) 740 { 741 struct pollfd pfd; 742 int ret; 743 744 while ((ret = (*func)(tls_ctx)) != 0) { 745 if (ret == TLS_WANT_POLLIN) 746 pfd.events = POLLIN; 747 else if (ret == TLS_WANT_POLLOUT) 748 pfd.events = POLLOUT; 749 else 750 break; 751 pfd.fd = s; 752 if ((ret = poll(&pfd, 1, timeout)) == 1) 753 continue; 754 else if (ret == 0) { 755 errno = ETIMEDOUT; 756 ret = -1; 757 break; 758 } else 759 err(1, "poll failed"); 760 } 761 762 return ret; 763 } 764 765 void 766 tls_setup_client(struct tls *tls_ctx, int s, char *host) 767 { 768 const char *errstr; 769 770 if (tls_connect_socket(tls_ctx, s, 771 tls_expectname ? tls_expectname : host) == -1) { 772 errx(1, "tls connection failed (%s)", 773 tls_error(tls_ctx)); 774 } 775 if (timeout_tls(s, tls_ctx, tls_handshake) == -1) { 776 if ((errstr = tls_error(tls_ctx)) == NULL) 777 errstr = strerror(errno); 778 errx(1, "tls handshake failed (%s)", errstr); 779 } 780 if (vflag) 781 report_tls(tls_ctx, host); 782 if (tls_expecthash && tls_peer_cert_hash(tls_ctx) && 783 strcmp(tls_expecthash, tls_peer_cert_hash(tls_ctx)) != 0) 784 errx(1, "peer certificate is not %s", tls_expecthash); 785 if (Zflag) { 786 save_peer_cert(tls_ctx, Zflag); 787 if (Zflag != stderr && (fclose(Zflag) != 0)) 788 err(1, "fclose failed saving peer cert"); 789 } 790 } 791 792 struct tls * 793 tls_setup_server(struct tls *tls_ctx, int connfd, char *host) 794 { 795 struct tls *tls_cctx; 796 const char *errstr; 797 798 if (tls_accept_socket(tls_ctx, &tls_cctx, connfd) == -1) { 799 warnx("tls accept failed (%s)", tls_error(tls_ctx)); 800 } else if (timeout_tls(connfd, tls_cctx, tls_handshake) == -1) { 801 if ((errstr = tls_error(tls_cctx)) == NULL) 802 errstr = strerror(errno); 803 warnx("tls handshake failed (%s)", errstr); 804 } else { 805 int gotcert = tls_peer_cert_provided(tls_cctx); 806 807 if (vflag && gotcert) 808 report_tls(tls_cctx, host); 809 if ((TLSopt & TLS_CCERT) && !gotcert) 810 warnx("No client certificate provided"); 811 else if (gotcert && tls_peer_cert_hash(tls_ctx) && tls_expecthash && 812 strcmp(tls_expecthash, tls_peer_cert_hash(tls_ctx)) != 0) 813 warnx("peer certificate is not %s", tls_expecthash); 814 else if (gotcert && tls_expectname && 815 (!tls_peer_cert_contains_name(tls_cctx, tls_expectname))) 816 warnx("name (%s) not found in client cert", 817 tls_expectname); 818 else { 819 return tls_cctx; 820 } 821 } 822 return NULL; 823 } 824 825 /* 826 * unix_connect() 827 * Returns a socket connected to a local unix socket. Returns -1 on failure. 828 */ 829 int 830 unix_connect(char *path) 831 { 832 struct sockaddr_un s_un; 833 int s, save_errno; 834 835 if (uflag) { 836 if ((s = unix_bind(unix_dg_tmp_socket, SOCK_CLOEXEC)) < 0) 837 return -1; 838 } else { 839 if ((s = socket(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC, 0)) < 0) 840 return -1; 841 } 842 843 memset(&s_un, 0, sizeof(struct sockaddr_un)); 844 s_un.sun_family = AF_UNIX; 845 846 if (strlcpy(s_un.sun_path, path, sizeof(s_un.sun_path)) >= 847 sizeof(s_un.sun_path)) { 848 close(s); 849 errno = ENAMETOOLONG; 850 return -1; 851 } 852 if (connect(s, (struct sockaddr *)&s_un, sizeof(s_un)) < 0) { 853 save_errno = errno; 854 close(s); 855 errno = save_errno; 856 return -1; 857 } 858 return s; 859 860 } 861 862 /* 863 * unix_listen() 864 * Create a unix domain socket, and listen on it. 865 */ 866 int 867 unix_listen(char *path) 868 { 869 int s; 870 if ((s = unix_bind(path, 0)) < 0) 871 return -1; 872 873 if (listen(s, 5) < 0) { 874 close(s); 875 return -1; 876 } 877 return s; 878 } 879 880 /* 881 * remote_connect() 882 * Returns a socket connected to a remote host. Properly binds to a local 883 * port or source address if needed. Returns -1 on failure. 884 */ 885 int 886 remote_connect(const char *host, const char *port, struct addrinfo hints) 887 { 888 struct addrinfo *res, *res0; 889 int s = -1, error, on = 1, save_errno; 890 891 if ((error = getaddrinfo(host, port, &hints, &res0))) 892 errx(1, "getaddrinfo for host \"%s\" port %s: %s", host, 893 port, gai_strerror(error)); 894 895 for (res = res0; res; res = res->ai_next) { 896 if ((s = socket(res->ai_family, res->ai_socktype | 897 SOCK_NONBLOCK, res->ai_protocol)) < 0) 898 continue; 899 900 /* Bind to a local port or source address if specified. */ 901 if (sflag || pflag) { 902 struct addrinfo ahints, *ares; 903 904 /* try SO_BINDANY, but don't insist */ 905 setsockopt(s, SOL_SOCKET, SO_BINDANY, &on, sizeof(on)); 906 memset(&ahints, 0, sizeof(struct addrinfo)); 907 ahints.ai_family = res->ai_family; 908 ahints.ai_socktype = uflag ? SOCK_DGRAM : SOCK_STREAM; 909 ahints.ai_protocol = uflag ? IPPROTO_UDP : IPPROTO_TCP; 910 ahints.ai_flags = AI_PASSIVE; 911 if ((error = getaddrinfo(sflag, pflag, &ahints, &ares))) 912 errx(1, "getaddrinfo: %s", gai_strerror(error)); 913 914 if (bind(s, (struct sockaddr *)ares->ai_addr, 915 ares->ai_addrlen) < 0) 916 err(1, "bind failed"); 917 freeaddrinfo(ares); 918 } 919 920 set_common_sockopts(s, res->ai_family); 921 922 if (timeout_connect(s, res->ai_addr, res->ai_addrlen) == 0) 923 break; 924 if (vflag) 925 warn("connect to %s port %s (%s) failed", host, port, 926 uflag ? "udp" : "tcp"); 927 928 save_errno = errno; 929 close(s); 930 errno = save_errno; 931 s = -1; 932 } 933 934 freeaddrinfo(res0); 935 936 return s; 937 } 938 939 int 940 timeout_connect(int s, const struct sockaddr *name, socklen_t namelen) 941 { 942 struct pollfd pfd; 943 socklen_t optlen; 944 int optval; 945 int ret; 946 947 if ((ret = connect(s, name, namelen)) != 0 && errno == EINPROGRESS) { 948 pfd.fd = s; 949 pfd.events = POLLOUT; 950 if ((ret = poll(&pfd, 1, timeout)) == 1) { 951 optlen = sizeof(optval); 952 if ((ret = getsockopt(s, SOL_SOCKET, SO_ERROR, 953 &optval, &optlen)) == 0) { 954 errno = optval; 955 ret = optval == 0 ? 0 : -1; 956 } 957 } else if (ret == 0) { 958 errno = ETIMEDOUT; 959 ret = -1; 960 } else 961 err(1, "poll failed"); 962 } 963 964 return ret; 965 } 966 967 /* 968 * local_listen() 969 * Returns a socket listening on a local port, binds to specified source 970 * address. Returns -1 on failure. 971 */ 972 int 973 local_listen(char *host, char *port, struct addrinfo hints) 974 { 975 struct addrinfo *res, *res0; 976 int s = -1, ret, x = 1, save_errno; 977 int error; 978 979 /* Allow nodename to be null. */ 980 hints.ai_flags |= AI_PASSIVE; 981 982 /* 983 * In the case of binding to a wildcard address 984 * default to binding to an ipv4 address. 985 */ 986 if (host == NULL && hints.ai_family == AF_UNSPEC) 987 hints.ai_family = AF_INET; 988 989 if ((error = getaddrinfo(host, port, &hints, &res0))) 990 errx(1, "getaddrinfo: %s", gai_strerror(error)); 991 992 for (res = res0; res; res = res->ai_next) { 993 if ((s = socket(res->ai_family, res->ai_socktype, 994 res->ai_protocol)) < 0) 995 continue; 996 997 ret = setsockopt(s, SOL_SOCKET, SO_REUSEPORT, &x, sizeof(x)); 998 if (ret == -1) 999 err(1, NULL); 1000 1001 set_common_sockopts(s, res->ai_family); 1002 1003 if (bind(s, (struct sockaddr *)res->ai_addr, 1004 res->ai_addrlen) == 0) 1005 break; 1006 1007 save_errno = errno; 1008 close(s); 1009 errno = save_errno; 1010 s = -1; 1011 } 1012 1013 if (!uflag && s != -1) { 1014 if (listen(s, 1) < 0) 1015 err(1, "listen"); 1016 } 1017 1018 freeaddrinfo(res0); 1019 1020 return s; 1021 } 1022 1023 /* 1024 * readwrite() 1025 * Loop that polls on the network file descriptor and stdin. 1026 */ 1027 void 1028 readwrite(int net_fd, struct tls *tls_ctx) 1029 { 1030 struct pollfd pfd[4]; 1031 int stdin_fd = STDIN_FILENO; 1032 int stdout_fd = STDOUT_FILENO; 1033 unsigned char netinbuf[BUFSIZE]; 1034 size_t netinbufpos = 0; 1035 unsigned char stdinbuf[BUFSIZE]; 1036 size_t stdinbufpos = 0; 1037 int n, num_fds; 1038 ssize_t ret; 1039 1040 /* don't read from stdin if requested */ 1041 if (dflag) 1042 stdin_fd = -1; 1043 1044 /* stdin */ 1045 pfd[POLL_STDIN].fd = stdin_fd; 1046 pfd[POLL_STDIN].events = POLLIN; 1047 1048 /* network out */ 1049 pfd[POLL_NETOUT].fd = net_fd; 1050 pfd[POLL_NETOUT].events = 0; 1051 1052 /* network in */ 1053 pfd[POLL_NETIN].fd = net_fd; 1054 pfd[POLL_NETIN].events = POLLIN; 1055 1056 /* stdout */ 1057 pfd[POLL_STDOUT].fd = stdout_fd; 1058 pfd[POLL_STDOUT].events = 0; 1059 1060 while (1) { 1061 /* both inputs are gone, buffers are empty, we are done */ 1062 if (pfd[POLL_STDIN].fd == -1 && pfd[POLL_NETIN].fd == -1 && 1063 stdinbufpos == 0 && netinbufpos == 0) 1064 return; 1065 /* both outputs are gone, we can't continue */ 1066 if (pfd[POLL_NETOUT].fd == -1 && pfd[POLL_STDOUT].fd == -1) 1067 return; 1068 /* listen and net in gone, queues empty, done */ 1069 if (lflag && pfd[POLL_NETIN].fd == -1 && 1070 stdinbufpos == 0 && netinbufpos == 0) 1071 return; 1072 1073 /* help says -i is for "wait between lines sent". We read and 1074 * write arbitrary amounts of data, and we don't want to start 1075 * scanning for newlines, so this is as good as it gets */ 1076 if (iflag) 1077 sleep(iflag); 1078 1079 /* poll */ 1080 num_fds = poll(pfd, 4, timeout); 1081 1082 /* treat poll errors */ 1083 if (num_fds == -1) 1084 err(1, "polling error"); 1085 1086 /* timeout happened */ 1087 if (num_fds == 0) 1088 return; 1089 1090 /* treat socket error conditions */ 1091 for (n = 0; n < 4; n++) { 1092 if (pfd[n].revents & (POLLERR|POLLNVAL)) { 1093 pfd[n].fd = -1; 1094 } 1095 } 1096 /* reading is possible after HUP */ 1097 if (pfd[POLL_STDIN].events & POLLIN && 1098 pfd[POLL_STDIN].revents & POLLHUP && 1099 !(pfd[POLL_STDIN].revents & POLLIN)) 1100 pfd[POLL_STDIN].fd = -1; 1101 1102 if (pfd[POLL_NETIN].events & POLLIN && 1103 pfd[POLL_NETIN].revents & POLLHUP && 1104 !(pfd[POLL_NETIN].revents & POLLIN)) 1105 pfd[POLL_NETIN].fd = -1; 1106 1107 if (pfd[POLL_NETOUT].revents & POLLHUP) { 1108 if (Nflag) 1109 shutdown(pfd[POLL_NETOUT].fd, SHUT_WR); 1110 pfd[POLL_NETOUT].fd = -1; 1111 } 1112 /* if HUP, stop watching stdout */ 1113 if (pfd[POLL_STDOUT].revents & POLLHUP) 1114 pfd[POLL_STDOUT].fd = -1; 1115 /* if no net out, stop watching stdin */ 1116 if (pfd[POLL_NETOUT].fd == -1) 1117 pfd[POLL_STDIN].fd = -1; 1118 /* if no stdout, stop watching net in */ 1119 if (pfd[POLL_STDOUT].fd == -1) { 1120 if (pfd[POLL_NETIN].fd != -1) 1121 shutdown(pfd[POLL_NETIN].fd, SHUT_RD); 1122 pfd[POLL_NETIN].fd = -1; 1123 } 1124 1125 /* try to read from stdin */ 1126 if (pfd[POLL_STDIN].revents & POLLIN && stdinbufpos < BUFSIZE) { 1127 ret = fillbuf(pfd[POLL_STDIN].fd, stdinbuf, 1128 &stdinbufpos, NULL); 1129 if (ret == TLS_WANT_POLLIN) 1130 pfd[POLL_STDIN].events = POLLIN; 1131 else if (ret == TLS_WANT_POLLOUT) 1132 pfd[POLL_STDIN].events = POLLOUT; 1133 else if (ret == 0 || ret == -1) 1134 pfd[POLL_STDIN].fd = -1; 1135 /* read something - poll net out */ 1136 if (stdinbufpos > 0) 1137 pfd[POLL_NETOUT].events = POLLOUT; 1138 /* filled buffer - remove self from polling */ 1139 if (stdinbufpos == BUFSIZE) 1140 pfd[POLL_STDIN].events = 0; 1141 } 1142 /* try to write to network */ 1143 if (pfd[POLL_NETOUT].revents & POLLOUT && stdinbufpos > 0) { 1144 ret = drainbuf(pfd[POLL_NETOUT].fd, stdinbuf, 1145 &stdinbufpos, tls_ctx); 1146 if (ret == TLS_WANT_POLLIN) 1147 pfd[POLL_NETOUT].events = POLLIN; 1148 else if (ret == TLS_WANT_POLLOUT) 1149 pfd[POLL_NETOUT].events = POLLOUT; 1150 else if (ret == -1) 1151 pfd[POLL_NETOUT].fd = -1; 1152 /* buffer empty - remove self from polling */ 1153 if (stdinbufpos == 0) 1154 pfd[POLL_NETOUT].events = 0; 1155 /* buffer no longer full - poll stdin again */ 1156 if (stdinbufpos < BUFSIZE) 1157 pfd[POLL_STDIN].events = POLLIN; 1158 } 1159 /* try to read from network */ 1160 if (pfd[POLL_NETIN].revents & POLLIN && netinbufpos < BUFSIZE) { 1161 ret = fillbuf(pfd[POLL_NETIN].fd, netinbuf, 1162 &netinbufpos, tls_ctx); 1163 if (ret == TLS_WANT_POLLIN) 1164 pfd[POLL_NETIN].events = POLLIN; 1165 else if (ret == TLS_WANT_POLLOUT) 1166 pfd[POLL_NETIN].events = POLLOUT; 1167 else if (ret == -1) 1168 pfd[POLL_NETIN].fd = -1; 1169 /* eof on net in - remove from pfd */ 1170 if (ret == 0) { 1171 shutdown(pfd[POLL_NETIN].fd, SHUT_RD); 1172 pfd[POLL_NETIN].fd = -1; 1173 } 1174 if (recvlimit > 0 && ++recvcount >= recvlimit) { 1175 if (pfd[POLL_NETIN].fd != -1) 1176 shutdown(pfd[POLL_NETIN].fd, SHUT_RD); 1177 pfd[POLL_NETIN].fd = -1; 1178 pfd[POLL_STDIN].fd = -1; 1179 } 1180 /* read something - poll stdout */ 1181 if (netinbufpos > 0) 1182 pfd[POLL_STDOUT].events = POLLOUT; 1183 /* filled buffer - remove self from polling */ 1184 if (netinbufpos == BUFSIZE) 1185 pfd[POLL_NETIN].events = 0; 1186 /* handle telnet */ 1187 if (tflag) 1188 atelnet(pfd[POLL_NETIN].fd, netinbuf, 1189 netinbufpos); 1190 } 1191 /* try to write to stdout */ 1192 if (pfd[POLL_STDOUT].revents & POLLOUT && netinbufpos > 0) { 1193 ret = drainbuf(pfd[POLL_STDOUT].fd, netinbuf, 1194 &netinbufpos, NULL); 1195 if (ret == TLS_WANT_POLLIN) 1196 pfd[POLL_STDOUT].events = POLLIN; 1197 else if (ret == TLS_WANT_POLLOUT) 1198 pfd[POLL_STDOUT].events = POLLOUT; 1199 else if (ret == -1) 1200 pfd[POLL_STDOUT].fd = -1; 1201 /* buffer empty - remove self from polling */ 1202 if (netinbufpos == 0) 1203 pfd[POLL_STDOUT].events = 0; 1204 /* buffer no longer full - poll net in again */ 1205 if (netinbufpos < BUFSIZE) 1206 pfd[POLL_NETIN].events = POLLIN; 1207 } 1208 1209 /* stdin gone and queue empty? */ 1210 if (pfd[POLL_STDIN].fd == -1 && stdinbufpos == 0) { 1211 if (pfd[POLL_NETOUT].fd != -1 && Nflag) 1212 shutdown(pfd[POLL_NETOUT].fd, SHUT_WR); 1213 pfd[POLL_NETOUT].fd = -1; 1214 } 1215 /* net in gone and queue empty? */ 1216 if (pfd[POLL_NETIN].fd == -1 && netinbufpos == 0) { 1217 pfd[POLL_STDOUT].fd = -1; 1218 } 1219 } 1220 } 1221 1222 ssize_t 1223 drainbuf(int fd, unsigned char *buf, size_t *bufpos, struct tls *tls) 1224 { 1225 ssize_t n; 1226 ssize_t adjust; 1227 1228 if (tls) 1229 n = tls_write(tls, buf, *bufpos); 1230 else { 1231 n = write(fd, buf, *bufpos); 1232 /* don't treat EAGAIN, EINTR as error */ 1233 if (n == -1 && (errno == EAGAIN || errno == EINTR)) 1234 n = TLS_WANT_POLLOUT; 1235 } 1236 if (n <= 0) 1237 return n; 1238 /* adjust buffer */ 1239 adjust = *bufpos - n; 1240 if (adjust > 0) 1241 memmove(buf, buf + n, adjust); 1242 *bufpos -= n; 1243 return n; 1244 } 1245 1246 ssize_t 1247 fillbuf(int fd, unsigned char *buf, size_t *bufpos, struct tls *tls) 1248 { 1249 size_t num = BUFSIZE - *bufpos; 1250 ssize_t n; 1251 1252 if (tls) 1253 n = tls_read(tls, buf + *bufpos, num); 1254 else { 1255 n = read(fd, buf + *bufpos, num); 1256 /* don't treat EAGAIN, EINTR as error */ 1257 if (n == -1 && (errno == EAGAIN || errno == EINTR)) 1258 n = TLS_WANT_POLLIN; 1259 } 1260 if (n <= 0) 1261 return n; 1262 *bufpos += n; 1263 return n; 1264 } 1265 1266 /* 1267 * fdpass() 1268 * Pass the connected file descriptor to stdout and exit. 1269 */ 1270 void 1271 fdpass(int nfd) 1272 { 1273 struct msghdr mh; 1274 union { 1275 struct cmsghdr hdr; 1276 char buf[CMSG_SPACE(sizeof(int))]; 1277 } cmsgbuf; 1278 struct cmsghdr *cmsg; 1279 struct iovec iov; 1280 char c = '\0'; 1281 ssize_t r; 1282 struct pollfd pfd; 1283 1284 /* Avoid obvious stupidity */ 1285 if (isatty(STDOUT_FILENO)) 1286 errx(1, "Cannot pass file descriptor to tty"); 1287 1288 bzero(&mh, sizeof(mh)); 1289 bzero(&cmsgbuf, sizeof(cmsgbuf)); 1290 bzero(&iov, sizeof(iov)); 1291 1292 mh.msg_control = (caddr_t)&cmsgbuf.buf; 1293 mh.msg_controllen = sizeof(cmsgbuf.buf); 1294 cmsg = CMSG_FIRSTHDR(&mh); 1295 cmsg->cmsg_len = CMSG_LEN(sizeof(int)); 1296 cmsg->cmsg_level = SOL_SOCKET; 1297 cmsg->cmsg_type = SCM_RIGHTS; 1298 *(int *)CMSG_DATA(cmsg) = nfd; 1299 1300 iov.iov_base = &c; 1301 iov.iov_len = 1; 1302 mh.msg_iov = &iov; 1303 mh.msg_iovlen = 1; 1304 1305 bzero(&pfd, sizeof(pfd)); 1306 pfd.fd = STDOUT_FILENO; 1307 pfd.events = POLLOUT; 1308 for (;;) { 1309 r = sendmsg(STDOUT_FILENO, &mh, 0); 1310 if (r == -1) { 1311 if (errno == EAGAIN || errno == EINTR) { 1312 if (poll(&pfd, 1, -1) == -1) 1313 err(1, "poll"); 1314 continue; 1315 } 1316 err(1, "sendmsg"); 1317 } else if (r != 1) 1318 errx(1, "sendmsg: unexpected return value %zd", r); 1319 else 1320 break; 1321 } 1322 exit(0); 1323 } 1324 1325 /* Deal with RFC 854 WILL/WONT DO/DONT negotiation. */ 1326 void 1327 atelnet(int nfd, unsigned char *buf, unsigned int size) 1328 { 1329 unsigned char *p, *end; 1330 unsigned char obuf[4]; 1331 1332 if (size < 3) 1333 return; 1334 end = buf + size - 2; 1335 1336 for (p = buf; p < end; p++) { 1337 if (*p != IAC) 1338 continue; 1339 1340 obuf[0] = IAC; 1341 p++; 1342 if ((*p == WILL) || (*p == WONT)) 1343 obuf[1] = DONT; 1344 else if ((*p == DO) || (*p == DONT)) 1345 obuf[1] = WONT; 1346 else 1347 continue; 1348 1349 p++; 1350 obuf[2] = *p; 1351 if (atomicio(vwrite, nfd, obuf, 3) != 3) 1352 warn("Write Error!"); 1353 } 1354 } 1355 1356 1357 int 1358 strtoport(char *portstr, int udp) 1359 { 1360 struct servent *entry; 1361 const char *errstr; 1362 char *proto; 1363 int port = -1; 1364 1365 proto = udp ? "udp" : "tcp"; 1366 1367 port = strtonum(portstr, 1, PORT_MAX, &errstr); 1368 if (errstr == NULL) 1369 return port; 1370 if (errno != EINVAL) 1371 errx(1, "port number %s: %s", errstr, portstr); 1372 if ((entry = getservbyname(portstr, proto)) == NULL) 1373 errx(1, "service \"%s\" unknown", portstr); 1374 return ntohs(entry->s_port); 1375 } 1376 1377 /* 1378 * build_ports() 1379 * Build an array of ports in portlist[], listing each port 1380 * that we should try to connect to. 1381 */ 1382 void 1383 build_ports(char *p) 1384 { 1385 char *n; 1386 int hi, lo, cp; 1387 int x = 0; 1388 1389 if ((n = strchr(p, '-')) != NULL) { 1390 *n = '\0'; 1391 n++; 1392 1393 /* Make sure the ports are in order: lowest->highest. */ 1394 hi = strtoport(n, uflag); 1395 lo = strtoport(p, uflag); 1396 if (lo > hi) { 1397 cp = hi; 1398 hi = lo; 1399 lo = cp; 1400 } 1401 1402 /* 1403 * Initialize portlist with a random permutation. Based on 1404 * Knuth, as in ip_randomid() in sys/netinet/ip_id.c. 1405 */ 1406 if (rflag) { 1407 for (x = 0; x <= hi - lo; x++) { 1408 cp = arc4random_uniform(x + 1); 1409 portlist[x] = portlist[cp]; 1410 if (asprintf(&portlist[cp], "%d", x + lo) < 0) 1411 err(1, "asprintf"); 1412 } 1413 } else { /* Load ports sequentially. */ 1414 for (cp = lo; cp <= hi; cp++) { 1415 if (asprintf(&portlist[x], "%d", cp) < 0) 1416 err(1, "asprintf"); 1417 x++; 1418 } 1419 } 1420 } else { 1421 char *tmp; 1422 1423 hi = strtoport(p, uflag); 1424 if (asprintf(&tmp, "%d", hi) != -1) 1425 portlist[0] = tmp; 1426 else 1427 err(1, NULL); 1428 } 1429 } 1430 1431 /* 1432 * udptest() 1433 * Do a few writes to see if the UDP port is there. 1434 * Fails once PF state table is full. 1435 */ 1436 int 1437 udptest(int s) 1438 { 1439 int i, ret; 1440 1441 for (i = 0; i <= 3; i++) { 1442 if (write(s, "X", 1) == 1) 1443 ret = 1; 1444 else 1445 ret = -1; 1446 } 1447 return ret; 1448 } 1449 1450 void 1451 set_common_sockopts(int s, int af) 1452 { 1453 int x = 1; 1454 1455 if (Sflag) { 1456 if (setsockopt(s, IPPROTO_TCP, TCP_MD5SIG, 1457 &x, sizeof(x)) == -1) 1458 err(1, NULL); 1459 } 1460 if (Dflag) { 1461 if (setsockopt(s, SOL_SOCKET, SO_DEBUG, 1462 &x, sizeof(x)) == -1) 1463 err(1, NULL); 1464 } 1465 if (Tflag != -1) { 1466 if (af == AF_INET && setsockopt(s, IPPROTO_IP, 1467 IP_TOS, &Tflag, sizeof(Tflag)) == -1) 1468 err(1, "set IP ToS"); 1469 1470 else if (af == AF_INET6 && setsockopt(s, IPPROTO_IPV6, 1471 IPV6_TCLASS, &Tflag, sizeof(Tflag)) == -1) 1472 err(1, "set IPv6 traffic class"); 1473 } 1474 if (Iflag) { 1475 if (setsockopt(s, SOL_SOCKET, SO_RCVBUF, 1476 &Iflag, sizeof(Iflag)) == -1) 1477 err(1, "set TCP receive buffer size"); 1478 } 1479 if (Oflag) { 1480 if (setsockopt(s, SOL_SOCKET, SO_SNDBUF, 1481 &Oflag, sizeof(Oflag)) == -1) 1482 err(1, "set TCP send buffer size"); 1483 } 1484 1485 if (ttl != -1) { 1486 if (af == AF_INET && setsockopt(s, IPPROTO_IP, 1487 IP_TTL, &ttl, sizeof(ttl))) 1488 err(1, "set IP TTL"); 1489 1490 else if (af == AF_INET6 && setsockopt(s, IPPROTO_IPV6, 1491 IPV6_UNICAST_HOPS, &ttl, sizeof(ttl))) 1492 err(1, "set IPv6 unicast hops"); 1493 } 1494 1495 if (minttl != -1) { 1496 if (af == AF_INET && setsockopt(s, IPPROTO_IP, 1497 IP_MINTTL, &minttl, sizeof(minttl))) 1498 err(1, "set IP min TTL"); 1499 1500 else if (af == AF_INET6 && setsockopt(s, IPPROTO_IPV6, 1501 IPV6_MINHOPCOUNT, &minttl, sizeof(minttl))) 1502 err(1, "set IPv6 min hop count"); 1503 } 1504 } 1505 1506 int 1507 process_tos_opt(char *s, int *val) 1508 { 1509 /* DiffServ Codepoints and other TOS mappings */ 1510 const struct toskeywords { 1511 const char *keyword; 1512 int val; 1513 } *t, toskeywords[] = { 1514 { "af11", IPTOS_DSCP_AF11 }, 1515 { "af12", IPTOS_DSCP_AF12 }, 1516 { "af13", IPTOS_DSCP_AF13 }, 1517 { "af21", IPTOS_DSCP_AF21 }, 1518 { "af22", IPTOS_DSCP_AF22 }, 1519 { "af23", IPTOS_DSCP_AF23 }, 1520 { "af31", IPTOS_DSCP_AF31 }, 1521 { "af32", IPTOS_DSCP_AF32 }, 1522 { "af33", IPTOS_DSCP_AF33 }, 1523 { "af41", IPTOS_DSCP_AF41 }, 1524 { "af42", IPTOS_DSCP_AF42 }, 1525 { "af43", IPTOS_DSCP_AF43 }, 1526 { "critical", IPTOS_PREC_CRITIC_ECP }, 1527 { "cs0", IPTOS_DSCP_CS0 }, 1528 { "cs1", IPTOS_DSCP_CS1 }, 1529 { "cs2", IPTOS_DSCP_CS2 }, 1530 { "cs3", IPTOS_DSCP_CS3 }, 1531 { "cs4", IPTOS_DSCP_CS4 }, 1532 { "cs5", IPTOS_DSCP_CS5 }, 1533 { "cs6", IPTOS_DSCP_CS6 }, 1534 { "cs7", IPTOS_DSCP_CS7 }, 1535 { "ef", IPTOS_DSCP_EF }, 1536 { "inetcontrol", IPTOS_PREC_INTERNETCONTROL }, 1537 { "lowdelay", IPTOS_LOWDELAY }, 1538 { "netcontrol", IPTOS_PREC_NETCONTROL }, 1539 { "reliability", IPTOS_RELIABILITY }, 1540 { "throughput", IPTOS_THROUGHPUT }, 1541 { NULL, -1 }, 1542 }; 1543 1544 for (t = toskeywords; t->keyword != NULL; t++) { 1545 if (strcmp(s, t->keyword) == 0) { 1546 *val = t->val; 1547 return 1; 1548 } 1549 } 1550 1551 return 0; 1552 } 1553 1554 int 1555 process_tls_opt(char *s, int *flags) 1556 { 1557 size_t len; 1558 char *v; 1559 1560 const struct tlskeywords { 1561 const char *keyword; 1562 int flag; 1563 char **value; 1564 } *t, tlskeywords[] = { 1565 { "ciphers", -1, &tls_ciphers }, 1566 { "clientcert", TLS_CCERT, NULL }, 1567 { "muststaple", TLS_MUSTSTAPLE, NULL }, 1568 { "noverify", TLS_NOVERIFY, NULL }, 1569 { "noname", TLS_NONAME, NULL }, 1570 { "protocols", -1, &tls_protocols }, 1571 { NULL, -1, NULL }, 1572 }; 1573 1574 len = strlen(s); 1575 if ((v = strchr(s, '=')) != NULL) { 1576 len = v - s; 1577 v++; 1578 } 1579 1580 for (t = tlskeywords; t->keyword != NULL; t++) { 1581 if (strlen(t->keyword) == len && 1582 strncmp(s, t->keyword, len) == 0) { 1583 if (t->value != NULL) { 1584 if (v == NULL) 1585 errx(1, "invalid tls value `%s'", s); 1586 *t->value = v; 1587 } else { 1588 *flags |= t->flag; 1589 } 1590 return 1; 1591 } 1592 } 1593 return 0; 1594 } 1595 1596 void 1597 save_peer_cert(struct tls *tls_ctx, FILE *fp) 1598 { 1599 const char *pem; 1600 size_t plen; 1601 1602 if ((pem = tls_peer_cert_chain_pem(tls_ctx, &plen)) == NULL) 1603 errx(1, "Can't get peer certificate"); 1604 if (fprintf(fp, "%.*s", (int)plen, pem) < 0) 1605 err(1, "unable to save peer cert"); 1606 if (fflush(fp) != 0) 1607 err(1, "unable to flush peer cert"); 1608 } 1609 1610 void 1611 report_tls(struct tls * tls_ctx, char * host) 1612 { 1613 time_t t; 1614 const char *ocsp_url; 1615 1616 fprintf(stderr, "TLS handshake negotiated %s/%s with host %s\n", 1617 tls_conn_version(tls_ctx), tls_conn_cipher(tls_ctx), host); 1618 fprintf(stderr, "Peer name: %s\n", 1619 tls_expectname ? tls_expectname : host); 1620 if (tls_peer_cert_subject(tls_ctx)) 1621 fprintf(stderr, "Subject: %s\n", 1622 tls_peer_cert_subject(tls_ctx)); 1623 if (tls_peer_cert_issuer(tls_ctx)) 1624 fprintf(stderr, "Issuer: %s\n", 1625 tls_peer_cert_issuer(tls_ctx)); 1626 if ((t = tls_peer_cert_notbefore(tls_ctx)) != -1) 1627 fprintf(stderr, "Valid From: %s", ctime(&t)); 1628 if ((t = tls_peer_cert_notafter(tls_ctx)) != -1) 1629 fprintf(stderr, "Valid Until: %s", ctime(&t)); 1630 if (tls_peer_cert_hash(tls_ctx)) 1631 fprintf(stderr, "Cert Hash: %s\n", 1632 tls_peer_cert_hash(tls_ctx)); 1633 ocsp_url = tls_peer_ocsp_url(tls_ctx); 1634 if (ocsp_url != NULL) 1635 fprintf(stderr, "OCSP URL: %s\n", ocsp_url); 1636 switch (tls_peer_ocsp_response_status(tls_ctx)) { 1637 case TLS_OCSP_RESPONSE_SUCCESSFUL: 1638 fprintf(stderr, "OCSP Stapling: %s\n", 1639 tls_peer_ocsp_result(tls_ctx) == NULL ? "" : 1640 tls_peer_ocsp_result(tls_ctx)); 1641 fprintf(stderr, 1642 " response_status=%d cert_status=%d crl_reason=%d\n", 1643 tls_peer_ocsp_response_status(tls_ctx), 1644 tls_peer_ocsp_cert_status(tls_ctx), 1645 tls_peer_ocsp_crl_reason(tls_ctx)); 1646 t = tls_peer_ocsp_this_update(tls_ctx); 1647 fprintf(stderr, " this update: %s", 1648 t != -1 ? ctime(&t) : "\n"); 1649 t = tls_peer_ocsp_next_update(tls_ctx); 1650 fprintf(stderr, " next update: %s", 1651 t != -1 ? ctime(&t) : "\n"); 1652 t = tls_peer_ocsp_revocation_time(tls_ctx); 1653 fprintf(stderr, " revocation: %s", 1654 t != -1 ? ctime(&t) : "\n"); 1655 break; 1656 case -1: 1657 break; 1658 default: 1659 fprintf(stderr, "OCSP Stapling: failure - response_status %d (%s)\n", 1660 tls_peer_ocsp_response_status(tls_ctx), 1661 tls_peer_ocsp_result(tls_ctx) == NULL ? "" : 1662 tls_peer_ocsp_result(tls_ctx)); 1663 break; 1664 1665 } 1666 } 1667 1668 void 1669 report_connect(const struct sockaddr *sa, socklen_t salen, char *path) 1670 { 1671 char remote_host[NI_MAXHOST]; 1672 char remote_port[NI_MAXSERV]; 1673 int herr; 1674 int flags = NI_NUMERICSERV; 1675 1676 if (path != NULL) { 1677 fprintf(stderr, "Connection on %s received!\n", path); 1678 return; 1679 } 1680 1681 if (nflag) 1682 flags |= NI_NUMERICHOST; 1683 1684 if ((herr = getnameinfo(sa, salen, 1685 remote_host, sizeof(remote_host), 1686 remote_port, sizeof(remote_port), 1687 flags)) != 0) { 1688 if (herr == EAI_SYSTEM) 1689 err(1, "getnameinfo"); 1690 else 1691 errx(1, "getnameinfo: %s", gai_strerror(herr)); 1692 } 1693 1694 fprintf(stderr, 1695 "Connection from %s %s " 1696 "received!\n", remote_host, remote_port); 1697 } 1698 1699 void 1700 help(void) 1701 { 1702 usage(0); 1703 fprintf(stderr, "\tCommand Summary:\n\ 1704 \t-4 Use IPv4\n\ 1705 \t-6 Use IPv6\n\ 1706 \t-C certfile Public key file\n\ 1707 \t-c Use TLS\n\ 1708 \t-D Enable the debug socket option\n\ 1709 \t-d Detach from stdin\n\ 1710 \t-e name\t Required name in peer certificate\n\ 1711 \t-F Pass socket fd\n\ 1712 \t-H hash\t Hash string of peer certificate\n\ 1713 \t-h This help text\n\ 1714 \t-I length TCP receive buffer length\n\ 1715 \t-i interval Delay interval for lines sent, ports scanned\n\ 1716 \t-K keyfile Private key file\n\ 1717 \t-k Keep inbound sockets open for multiple connects\n\ 1718 \t-l Listen mode, for inbound connects\n\ 1719 \t-M ttl Outgoing TTL / Hop Limit\n\ 1720 \t-m minttl Minimum incoming TTL / Hop Limit\n\ 1721 \t-N Shutdown the network socket after EOF on stdin\n\ 1722 \t-n Suppress name/port resolutions\n\ 1723 \t-O length TCP send buffer length\n\ 1724 \t-o staplefile Staple file\n\ 1725 \t-P proxyuser\tUsername for proxy authentication\n\ 1726 \t-p port\t Specify local port for remote connects\n\ 1727 \t-R CAfile CA bundle\n\ 1728 \t-r Randomize remote ports\n\ 1729 \t-S Enable the TCP MD5 signature option\n\ 1730 \t-s source Local source address\n\ 1731 \t-T keyword TOS value or TLS options\n\ 1732 \t-t Answer TELNET negotiation\n\ 1733 \t-U Use UNIX domain socket\n\ 1734 \t-u UDP mode\n\ 1735 \t-V rtable Specify alternate routing table\n\ 1736 \t-v Verbose\n\ 1737 \t-W recvlimit Terminate after receiving a number of packets\n\ 1738 \t-w timeout Timeout for connects and final net reads\n\ 1739 \t-X proto Proxy protocol: \"4\", \"5\" (SOCKS) or \"connect\"\n\ 1740 \t-x addr[:port]\tSpecify proxy address and port\n\ 1741 \t-Z Peer certificate file\n\ 1742 \t-z Zero-I/O mode [used for scanning]\n\ 1743 Port numbers can be individual or ranges: lo-hi [inclusive]\n"); 1744 exit(1); 1745 } 1746 1747 void 1748 usage(int ret) 1749 { 1750 fprintf(stderr, 1751 "usage: nc [-46cDdFhklNnrStUuvz] [-C certfile] [-e name] " 1752 "[-H hash] [-I length]\n" 1753 "\t [-i interval] [-K keyfile] [-M ttl] [-m minttl] [-O length]\n" 1754 "\t [-o staplefile] [-P proxy_username] [-p source_port] " 1755 "[-R CAfile]\n" 1756 "\t [-s source] [-T keyword] [-V rtable] [-W recvlimit] " 1757 "[-w timeout]\n" 1758 "\t [-X proxy_protocol] [-x proxy_address[:port]] " 1759 "[-Z peercertfile]\n" 1760 "\t [destination] [port]\n"); 1761 if (ret) 1762 exit(1); 1763 } 1764