1 /* $OpenBSD: netcat.c,v 1.172 2017/02/05 01:39:14 jca 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 #include <sys/cdefs.h>
30 __RCSID("$NetBSD: netcat.c,v 1.7 2023/06/20 08:51:24 rin Exp $");
31
32 /*
33 * Re-written nc(1) for OpenBSD. Original implementation by
34 * *Hobbit* <hobbit@avian.org>.
35 */
36
37 #include <sys/types.h>
38 #include <sys/socket.h>
39 #include <sys/uio.h>
40 #include <sys/un.h>
41
42 #include <netinet/in.h>
43 #include <netinet/tcp.h>
44 #include <netinet/ip.h>
45 #include <arpa/telnet.h>
46
47 #include <err.h>
48 #include <errno.h>
49 #include <limits.h>
50 #include <netdb.h>
51 #include <poll.h>
52 #include <signal.h>
53 #include <stdarg.h>
54 #include <stdio.h>
55 #include <stdlib.h>
56 #include <string.h>
57 #include <time.h>
58 #include <unistd.h>
59 #ifdef CRYPTO
60 #include <tls.h>
61 #else
62 #define TLS_WANT_POLLIN -2
63 #define TLS_WANT_POLLOUT -2
64 #endif
65 #include "atomicio.h"
66
67 #ifdef __NetBSD__
68 #define accept4(a, b, c, d) paccept((a), (b), (c), NULL, (d))
69 #endif
70
71 #define PORT_MAX 65535
72 #define UNIX_DG_TMP_SOCKET_SIZE 19
73
74 #define POLL_STDIN 0
75 #define POLL_NETOUT 1
76 #define POLL_NETIN 2
77 #define POLL_STDOUT 3
78 #define BUFSIZE 16384
79 #define DEFAULT_CA_FILE "/etc/ssl/cert.pem"
80
81 #define TLS_ALL (1 << 1)
82 #define TLS_NOVERIFY (1 << 2)
83 #define TLS_NONAME (1 << 3)
84 #define TLS_CCERT (1 << 4)
85 #define TLS_MUSTSTAPLE (1 << 5)
86
87 /* Command Line Options */
88 int dflag; /* detached, no stdin */
89 int Fflag; /* fdpass sock to stdout */
90 unsigned int iflag; /* Interval Flag */
91 int kflag; /* More than one connect */
92 int lflag; /* Bind to local port */
93 int Nflag; /* shutdown() network socket */
94 int nflag; /* Don't do name look up */
95 char *Pflag; /* Proxy username */
96 char *pflag; /* Localport flag */
97 int rflag; /* Random ports flag */
98 char *sflag; /* Source Address */
99 int tflag; /* Telnet Emulation */
100 int uflag; /* UDP - Default to TCP */
101 int vflag; /* Verbosity */
102 int xflag; /* Socks proxy */
103 int zflag; /* Port Scan Flag */
104 int Dflag; /* sodebug */
105 int Iflag; /* TCP receive buffer size */
106 int Oflag; /* TCP send buffer size */
107 int Sflag; /* TCP MD5 signature option */
108 int Tflag = -1; /* IP Type of Service */
109 #ifdef __OpenBSD__
110 int rtableid = -1;
111 #endif
112
113 int usetls; /* use TLS */
114 char *Cflag; /* Public cert file */
115 char *Kflag; /* Private key file */
116 char *oflag; /* OCSP stapling file */
117 const char *Rflag = DEFAULT_CA_FILE; /* Root CA file */
118 int tls_cachanged; /* Using non-default CA file */
119 int TLSopt; /* TLS options */
120 char *tls_expectname; /* required name in peer cert */
121 char *tls_expecthash; /* required hash of peer cert */
122
123 int timeout = -1;
124 int family = AF_UNSPEC;
125 char *portlist[PORT_MAX+1];
126 char *unix_dg_tmp_socket;
127 int ttl = -1;
128 int minttl = -1;
129
130 void atelnet(int, unsigned char *, unsigned int);
131 void build_ports(char *);
132 static void help(void) __dead;
133 int local_listen(char *, char *, struct addrinfo);
134 struct tls;
135 void readwrite(int, struct tls *);
136 void fdpass(int nfd) __dead;
137 int remote_connect(const char *, const char *, struct addrinfo);
138 int timeout_connect(int, const struct sockaddr *, socklen_t);
139 int socks_connect(const char *, const char *, struct addrinfo,
140 const char *, const char *, struct addrinfo, int, const char *);
141 int udptest(int);
142 int unix_bind(char *, int);
143 int unix_connect(char *);
144 int unix_listen(char *);
145 void set_common_sockopts(int, int);
146 int map_tos(char *, int *);
147 int map_tls(char *, int *);
148 void report_connect(const struct sockaddr *, socklen_t, char *);
149 void report_tls(struct tls *tls_ctx, char * host, char *tlsexpectname);
150 void usage(int);
151 ssize_t drainbuf(int, unsigned char *, size_t *, struct tls *);
152 ssize_t fillbuf(int, unsigned char *, size_t *, struct tls *);
153 void tls_setup_client(struct tls *, int, char *);
154 struct tls *tls_setup_server(struct tls *, int, char *);
155
156 int
main(int argc,char * argv[])157 main(int argc, char *argv[])
158 {
159 int ch, s = -1, ret, socksv;
160 char *host, *uport;
161 struct addrinfo hints;
162 struct servent *sv;
163 socklen_t len;
164 struct sockaddr_storage cliaddr;
165 char *proxy = NULL, *proxyport = NULL;
166 int errnum;
167 struct addrinfo proxyhints;
168 char unix_dg_tmp_socket_buf[UNIX_DG_TMP_SOCKET_SIZE];
169 #ifdef CRYPTO
170 struct tls_config *tls_cfg = NULL;
171 struct tls *tls_ctx = NULL;
172 #endif
173
174 ret = 1;
175 socksv = 5;
176 host = NULL;
177 uport = NULL;
178 sv = NULL;
179
180 signal(SIGPIPE, SIG_IGN);
181
182 while ((ch = getopt(argc, argv,
183 #ifdef CRYPTO
184 "46C:cDde:FH:hI:i:K:klM:m:NnO:o:P:p:R:rSs:T:tUuV:vw:X:x:z"
185 #else
186 "46Dde:FhI:i:klM:m:NnO:P:p:rSs:tUuvw:X:x:z"
187 #endif
188 )) != -1) {
189 switch (ch) {
190 case '4':
191 family = AF_INET;
192 break;
193 case '6':
194 family = AF_INET6;
195 break;
196 case 'U':
197 family = AF_UNIX;
198 break;
199 case 'X':
200 if (strcasecmp(optarg, "connect") == 0)
201 socksv = -1; /* HTTP proxy CONNECT */
202 else if (strcmp(optarg, "4") == 0)
203 socksv = 4; /* SOCKS v.4 */
204 else if (strcmp(optarg, "5") == 0)
205 socksv = 5; /* SOCKS v.5 */
206 else
207 errx(1, "unsupported proxy protocol");
208 break;
209 #ifdef CRYPTO
210 case 'C':
211 Cflag = optarg;
212 break;
213 case 'c':
214 usetls = 1;
215 break;
216 #endif
217 case 'd':
218 dflag = 1;
219 break;
220 case 'e':
221 tls_expectname = optarg;
222 break;
223 case 'F':
224 Fflag = 1;
225 break;
226 #ifdef CRYPTO
227 case 'H':
228 tls_expecthash = optarg;
229 break;
230 #endif
231 case 'h':
232 help();
233 break;
234 case 'i':
235 iflag = strtoi(optarg, NULL, 0, 0, UINT_MAX, &errnum);
236 if (errnum)
237 errc(1, errnum, "bad interval `%s'", optarg);
238 break;
239 #ifdef CRYPTO
240 case 'K':
241 Kflag = optarg;
242 break;
243 #endif
244 case 'k':
245 kflag = 1;
246 break;
247 case 'l':
248 lflag = 1;
249 break;
250 case 'M':
251 ttl = strtoi(optarg, NULL, 0, 0, 255, &errnum);
252 if (errnum)
253 errc(1, errnum, "bad ttl `%s'", optarg);
254 break;
255 case 'm':
256 minttl = strtoi(optarg, NULL, 0, 0, 255, &errnum);
257 if (errnum)
258 errc(1, errnum, "bad minttl `%s'", optarg);
259 break;
260 case 'N':
261 Nflag = 1;
262 break;
263 case 'n':
264 nflag = 1;
265 break;
266 case 'P':
267 Pflag = optarg;
268 break;
269 case 'p':
270 pflag = optarg;
271 break;
272 #ifdef CRYPTO
273 case 'R':
274 tls_cachanged = 1;
275 Rflag = optarg;
276 break;
277 #endif
278 case 'r':
279 rflag = 1;
280 break;
281 case 's':
282 sflag = optarg;
283 break;
284 case 't':
285 tflag = 1;
286 break;
287 case 'u':
288 uflag = 1;
289 break;
290 #ifdef __OpenBSD__
291 case 'V':
292 rtableid = (int)strtoi(optarg, NULL, 0, 0, 255, &errnum);
293 if (errnum)
294 errc(1, errnum, "bad rtable `%s'", optarg);
295 break;
296 #endif
297 case 'v':
298 vflag = 1;
299 break;
300 case 'w':
301 timeout = strtoi(optarg, NULL, 0, 0, INT_MAX / 1000, &errnum);
302 if (errnum)
303 errc(1, errnum, "bad timeout `%s'", optarg);
304 timeout *= 1000;
305 break;
306 case 'x':
307 xflag = 1;
308 if ((proxy = strdup(optarg)) == NULL)
309 err(1, NULL);
310 break;
311 case 'z':
312 zflag = 1;
313 break;
314 case 'D':
315 Dflag = 1;
316 break;
317 case 'I':
318 Iflag = strtoi(optarg, NULL, 0, 1, 65536 << 14, &errnum);
319 if (errnum)
320 errc(1, errnum, "bad TCP receive window `%s'",
321 optarg);
322 break;
323 case 'O':
324 Oflag = strtoi(optarg, NULL, 0, 1, 65536 << 14, &errnum);
325 if (errnum)
326 errc(1, errnum, "bad TCP send window `%s'",
327 optarg);
328 break;
329 #ifdef CRYPTO
330 case 'o':
331 oflag = optarg;
332 break;
333 #endif
334 case 'S':
335 Sflag = 1;
336 break;
337 #ifdef CRYPTO
338 case 'T':
339 if (map_tos(optarg, &Tflag))
340 break;
341 if (map_tls(optarg, &TLSopt))
342 break;
343 Tflag = (int)strtoi(optarg, NULL, 0, 0, 255, &errnum);
344 if (errnum)
345 errc(1, errnum, "illegal tos/tls value `%s'",
346 optarg);
347 break;
348 #endif
349 default:
350 usage(1);
351 }
352 }
353 argc -= optind;
354 argv += optind;
355
356 #ifdef __OpenBSD__
357 if (rtableid >= 0)
358 if (setrtable(rtableid) == -1)
359 err(1, "setrtable");
360
361 if (family == AF_UNIX) {
362 if (pledge("stdio rpath wpath cpath tmppath unix", NULL) == -1)
363 err(1, "pledge");
364 } else if (Fflag) {
365 if (Pflag) {
366 if (pledge("stdio inet dns sendfd tty", NULL) == -1)
367 err(1, "pledge");
368 } else if (pledge("stdio inet dns sendfd", NULL) == -1)
369 err(1, "pledge");
370 } else if (Pflag) {
371 if (pledge("stdio inet dns tty", NULL) == -1)
372 err(1, "pledge");
373 } else if (usetls) {
374 if (pledge("stdio rpath inet dns", NULL) == -1)
375 err(1, "pledge");
376 } else if (pledge("stdio inet dns", NULL) == -1)
377 err(1, "pledge");
378 #endif
379
380 /* Cruft to make sure options are clean, and used properly. */
381 if (argv[0] && !argv[1] && family == AF_UNIX) {
382 host = argv[0];
383 uport = NULL;
384 } else if (argv[0] && !argv[1]) {
385 if (!lflag)
386 usage(1);
387 uport = argv[0];
388 host = NULL;
389 } else if (argv[0] && argv[1]) {
390 host = argv[0];
391 uport = argv[1];
392 } else
393 usage(1);
394
395 if (lflag && sflag)
396 errx(1, "cannot use -s and -l");
397 if (lflag && pflag)
398 errx(1, "cannot use -p and -l");
399 if (lflag && zflag)
400 errx(1, "cannot use -z and -l");
401 if (!lflag && kflag)
402 errx(1, "must use -l with -k");
403 if (uflag && usetls)
404 errx(1, "cannot use -c and -u");
405 if ((family == AF_UNIX) && usetls)
406 errx(1, "cannot use -c and -U");
407 if ((family == AF_UNIX) && Fflag)
408 errx(1, "cannot use -F and -U");
409 if (Fflag && usetls)
410 errx(1, "cannot use -c and -F");
411 #ifdef CRYPTO
412 if (TLSopt && !usetls)
413 errx(1, "you must specify -c to use TLS options");
414 if (Cflag && !usetls)
415 errx(1, "you must specify -c to use -C");
416 if (Kflag && !usetls)
417 errx(1, "you must specify -c to use -K");
418 if (oflag && !Cflag)
419 errx(1, "you must specify -C to use -o");
420 if (tls_cachanged && !usetls)
421 errx(1, "you must specify -c to use -R");
422 if (tls_expecthash && !usetls)
423 errx(1, "you must specify -c to use -H");
424 if (tls_expectname && !usetls)
425 errx(1, "you must specify -c to use -e");
426 #endif
427
428 /* Get name of temporary socket for unix datagram client */
429 if ((family == AF_UNIX) && uflag && !lflag) {
430 if (sflag) {
431 unix_dg_tmp_socket = sflag;
432 } else {
433 int fd;
434 snprintf(unix_dg_tmp_socket_buf,
435 sizeof(unix_dg_tmp_socket_buf),
436 "/tmp/%s.XXXXXXXXXX", getprogname());
437 /* XXX: abstract sockets instead? */
438 if ((fd = mkstemp(unix_dg_tmp_socket_buf)) == -1)
439 err(1, "mktemp");
440 close(fd);
441 unix_dg_tmp_socket = unix_dg_tmp_socket_buf;
442 }
443 }
444
445 /* Initialize addrinfo structure. */
446 if (family != AF_UNIX) {
447 memset(&hints, 0, sizeof(struct addrinfo));
448 hints.ai_family = family;
449 hints.ai_socktype = uflag ? SOCK_DGRAM : SOCK_STREAM;
450 hints.ai_protocol = uflag ? IPPROTO_UDP : IPPROTO_TCP;
451 if (nflag)
452 hints.ai_flags |= AI_NUMERICHOST;
453 }
454
455 if (xflag) {
456 if (uflag)
457 errx(1, "no proxy support for UDP mode");
458
459 if (lflag)
460 errx(1, "no proxy support for listen");
461
462 if (family == AF_UNIX)
463 errx(1, "no proxy support for unix sockets");
464
465 if (sflag)
466 errx(1, "no proxy support for local source address");
467
468 if (*proxy == '[') {
469 ++proxy;
470 proxyport = strchr(proxy, ']');
471 if (proxyport == NULL)
472 errx(1, "missing closing bracket in proxy");
473 *proxyport++ = '\0';
474 if (*proxyport == '\0')
475 /* Use default proxy port. */
476 proxyport = NULL;
477 else {
478 if (*proxyport == ':')
479 ++proxyport;
480 else
481 errx(1, "garbage proxy port delimiter");
482 }
483 } else {
484 proxyport = strrchr(proxy, ':');
485 if (proxyport != NULL)
486 *proxyport++ = '\0';
487 }
488
489 memset(&proxyhints, 0, sizeof(struct addrinfo));
490 proxyhints.ai_family = family;
491 proxyhints.ai_socktype = SOCK_STREAM;
492 proxyhints.ai_protocol = IPPROTO_TCP;
493 if (nflag)
494 proxyhints.ai_flags |= AI_NUMERICHOST;
495 }
496
497 #ifdef CRYPTO
498 if (usetls) {
499 #if __OpenBSD__
500 if (Pflag) {
501 if (pledge("stdio inet dns tty rpath", NULL) == -1)
502 err(1, "pledge");
503 } else if (pledge("stdio inet dns rpath", NULL) == -1)
504 err(1, "pledge");
505 #endif
506
507 if (tls_init() == -1)
508 errx(1, "unable to initialize TLS");
509 if ((tls_cfg = tls_config_new()) == NULL)
510 errx(1, "unable to allocate TLS config");
511 if (Rflag && tls_config_set_ca_file(tls_cfg, Rflag) == -1)
512 errx(1, "%s", tls_config_error(tls_cfg));
513 if (Cflag && tls_config_set_cert_file(tls_cfg, Cflag) == -1)
514 errx(1, "%s", tls_config_error(tls_cfg));
515 if (Kflag && tls_config_set_key_file(tls_cfg, Kflag) == -1)
516 errx(1, "%s", tls_config_error(tls_cfg));
517 if (oflag && tls_config_set_ocsp_staple_file(tls_cfg, oflag) == -1)
518 errx(1, "%s", tls_config_error(tls_cfg));
519 if (TLSopt & TLS_ALL) {
520 if (tls_config_set_protocols(tls_cfg,
521 TLS_PROTOCOLS_ALL) != 0)
522 errx(1, "%s", tls_config_error(tls_cfg));
523 if (tls_config_set_ciphers(tls_cfg, "all") != 0)
524 errx(1, "%s", tls_config_error(tls_cfg));
525 }
526 if (!lflag && (TLSopt & TLS_CCERT))
527 errx(1, "clientcert is only valid with -l");
528 if (TLSopt & TLS_NONAME)
529 tls_config_insecure_noverifyname(tls_cfg);
530 if (TLSopt & TLS_NOVERIFY) {
531 if (tls_expecthash != NULL)
532 errx(1, "-H and -T noverify may not be used"
533 "together");
534 tls_config_insecure_noverifycert(tls_cfg);
535 }
536 if (TLSopt & TLS_MUSTSTAPLE)
537 tls_config_ocsp_require_stapling(tls_cfg);
538
539 #ifdef __OpenBSD__
540 if (Pflag) {
541 if (pledge("stdio inet dns tty", NULL) == -1)
542 err(1, "pledge");
543 } else if (pledge("stdio inet dns", NULL) == -1)
544 err(1, "pledge");
545 #endif
546 }
547 #endif
548 if (lflag) {
549 #ifdef CRYPTO
550 struct tls *tls_cctx = NULL;
551 #endif
552 int connfd;
553 ret = 0;
554
555 if (family == AF_UNIX) {
556 if (uflag)
557 s = unix_bind(host, 0);
558 else
559 s = unix_listen(host);
560 }
561
562 #ifdef CRYPTO
563 if (usetls) {
564 tls_config_verify_client_optional(tls_cfg);
565 if ((tls_ctx = tls_server()) == NULL)
566 errx(1, "tls server creation failed");
567 if (tls_configure(tls_ctx, tls_cfg) == -1)
568 errx(1, "tls configuration failed (%s)",
569 tls_error(tls_ctx));
570 }
571 #endif
572 /* Allow only one connection at a time, but stay alive. */
573 for (;;) {
574 if (family != AF_UNIX)
575 s = local_listen(host, uport, hints);
576 if (s < 0)
577 err(1, NULL);
578 /*
579 * For UDP and -k, don't connect the socket, let it
580 * receive datagrams from multiple socket pairs.
581 */
582 if (uflag && kflag)
583 readwrite(s, NULL);
584 /*
585 * For UDP and not -k, we will use recvfrom() initially
586 * to wait for a caller, then use the regular functions
587 * to talk to the caller.
588 */
589 else if (uflag && !kflag) {
590 int rv, plen;
591 char buf[16384];
592 struct sockaddr_storage z;
593
594 len = sizeof(z);
595 plen = 2048;
596 rv = recvfrom(s, buf, plen, MSG_PEEK,
597 (struct sockaddr *)&z, &len);
598 if (rv < 0)
599 err(1, "recvfrom");
600
601 rv = connect(s, (struct sockaddr *)&z, len);
602 if (rv < 0)
603 err(1, "connect");
604
605 if (vflag)
606 report_connect((struct sockaddr *)&z, len, NULL);
607
608 readwrite(s, NULL);
609 } else {
610 len = sizeof(cliaddr);
611 connfd = accept4(s, (struct sockaddr *)&cliaddr,
612 &len, SOCK_NONBLOCK);
613 if (connfd == -1) {
614 /* For now, all errnos are fatal */
615 err(1, "accept");
616 }
617 if (vflag)
618 report_connect((struct sockaddr *)&cliaddr, len,
619 family == AF_UNIX ? host : NULL);
620 #ifdef CRYPTO
621 if ((usetls) &&
622 (tls_cctx = tls_setup_server(tls_ctx, connfd, host)))
623 readwrite(connfd, tls_cctx);
624 if (!usetls)
625 #endif
626 readwrite(connfd, NULL);
627 #ifdef CRYPTO
628 if (tls_cctx) {
629 int i;
630
631 do {
632 i = tls_close(tls_cctx);
633 } while (i == TLS_WANT_POLLIN ||
634 i == TLS_WANT_POLLOUT);
635 tls_free(tls_cctx);
636 tls_cctx = NULL;
637 }
638 #endif
639 close(connfd);
640 }
641 if (family != AF_UNIX)
642 close(s);
643 else if (uflag) {
644 if (connect(s, NULL, 0) < 0)
645 err(1, "connect");
646 }
647
648 if (!kflag)
649 break;
650 }
651 } else if (family == AF_UNIX) {
652 ret = 0;
653
654 if ((s = unix_connect(host)) > 0 && !zflag) {
655 readwrite(s, NULL);
656 close(s);
657 } else
658 ret = 1;
659
660 if (uflag)
661 unlink(unix_dg_tmp_socket);
662 exit(ret);
663
664 } else {
665 int i = 0;
666
667 /* Construct the portlist[] array. */
668 build_ports(uport);
669
670 /* Cycle through portlist, connecting to each port. */
671 for (s = -1, i = 0; portlist[i] != NULL; i++) {
672 if (s != -1)
673 close(s);
674
675 #ifdef CRYPTO
676 if (usetls) {
677 if ((tls_ctx = tls_client()) == NULL)
678 errx(1, "tls client creation failed");
679 if (tls_configure(tls_ctx, tls_cfg) == -1)
680 errx(1, "tls configuration failed (%s)",
681 tls_error(tls_ctx));
682 }
683 #endif
684 if (xflag)
685 s = socks_connect(host, portlist[i], hints,
686 proxy, proxyport, proxyhints, socksv,
687 Pflag);
688 else
689 s = remote_connect(host, portlist[i], hints);
690
691 if (s == -1)
692 continue;
693
694 ret = 0;
695 if (vflag || zflag) {
696 /* For UDP, make sure we are connected. */
697 if (uflag) {
698 if (udptest(s) == -1) {
699 ret = 1;
700 continue;
701 }
702 }
703
704 /* Don't look up port if -n. */
705 if (nflag)
706 sv = NULL;
707 else {
708 sv = getservbyport(
709 ntohs(atoi(portlist[i])),
710 uflag ? "udp" : "tcp");
711 }
712
713 fprintf(stderr,
714 "Connection to %s %s port [%s/%s] "
715 "succeeded!\n", host, portlist[i],
716 uflag ? "udp" : "tcp",
717 sv ? sv->s_name : "*");
718 }
719 if (Fflag)
720 fdpass(s);
721 else {
722 #ifdef CRYPTO
723 if (usetls)
724 tls_setup_client(tls_ctx, s, host);
725 if (!zflag)
726 readwrite(s, tls_ctx);
727 if (tls_ctx) {
728 int j;
729
730 do {
731 j = tls_close(tls_ctx);
732 } while (j == TLS_WANT_POLLIN ||
733 j == TLS_WANT_POLLOUT);
734 tls_free(tls_ctx);
735 tls_ctx = NULL;
736 }
737 #else
738 if (!zflag)
739 readwrite(s, NULL);
740 #endif
741 }
742 }
743 }
744
745 if (s != -1)
746 close(s);
747
748 #ifdef CRYPTO
749 tls_config_free(tls_cfg);
750 #endif
751
752 exit(ret);
753 }
754
755 /*
756 * unix_bind()
757 * Returns a unix socket bound to the given path
758 */
759 int
unix_bind(char * path,int flags)760 unix_bind(char *path, int flags)
761 {
762 struct sockaddr_un s_un;
763 int s, save_errno;
764
765 /* Create unix domain socket. */
766 if ((s = socket(AF_UNIX, flags | (uflag ? SOCK_DGRAM : SOCK_STREAM),
767 0)) < 0)
768 return (-1);
769
770 memset(&s_un, 0, sizeof(struct sockaddr_un));
771 s_un.sun_family = AF_UNIX;
772
773 if (strlcpy(s_un.sun_path, path, sizeof(s_un.sun_path)) >=
774 sizeof(s_un.sun_path)) {
775 close(s);
776 errno = ENAMETOOLONG;
777 return (-1);
778 }
779
780 if (bind(s, (struct sockaddr *)&s_un, sizeof(s_un)) < 0) {
781 save_errno = errno;
782 close(s);
783 errno = save_errno;
784 return (-1);
785 }
786 return (s);
787 }
788
789 #ifdef CRYPTO
790 void
tls_setup_client(struct tls * tls_ctx,int s,char * host)791 tls_setup_client(struct tls *tls_ctx, int s, char *host)
792 {
793 int i;
794
795 if (tls_connect_socket(tls_ctx, s,
796 tls_expectname ? tls_expectname : host) == -1) {
797 errx(1, "tls connection failed (%s)",
798 tls_error(tls_ctx));
799 }
800 do {
801 if ((i = tls_handshake(tls_ctx)) == -1)
802 errx(1, "tls handshake failed (%s)",
803 tls_error(tls_ctx));
804 } while (i == TLS_WANT_POLLIN || i == TLS_WANT_POLLOUT);
805 if (vflag)
806 report_tls(tls_ctx, host, tls_expectname);
807 if (tls_expecthash && tls_peer_cert_hash(tls_ctx) &&
808 strcmp(tls_expecthash, tls_peer_cert_hash(tls_ctx)) != 0)
809 errx(1, "peer certificate is not %s", tls_expecthash);
810 }
811
812 struct tls *
tls_setup_server(struct tls * tls_ctx,int connfd,char * host)813 tls_setup_server(struct tls *tls_ctx, int connfd, char *host)
814 {
815 struct tls *tls_cctx;
816
817 if (tls_accept_socket(tls_ctx, &tls_cctx,
818 connfd) == -1) {
819 warnx("tls accept failed (%s)",
820 tls_error(tls_ctx));
821 tls_cctx = NULL;
822 } else {
823 int i;
824
825 do {
826 if ((i = tls_handshake(tls_cctx)) == -1)
827 warnx("tls handshake failed (%s)",
828 tls_error(tls_cctx));
829 } while(i == TLS_WANT_POLLIN || i == TLS_WANT_POLLOUT);
830 }
831 if (tls_cctx) {
832 int gotcert = tls_peer_cert_provided(tls_cctx);
833
834 if (vflag && gotcert)
835 report_tls(tls_cctx, host, tls_expectname);
836 if ((TLSopt & TLS_CCERT) && !gotcert)
837 warnx("No client certificate provided");
838 else if (gotcert && tls_peer_cert_hash(tls_ctx) && tls_expecthash &&
839 strcmp(tls_expecthash, tls_peer_cert_hash(tls_ctx)) != 0)
840 warnx("peer certificate is not %s", tls_expecthash);
841 else if (gotcert && tls_expectname &&
842 (!tls_peer_cert_contains_name(tls_cctx, tls_expectname)))
843 warnx("name (%s) not found in client cert",
844 tls_expectname);
845 else {
846 return tls_cctx;
847 }
848 }
849 return NULL;
850 }
851 #endif
852
853 /*
854 * unix_connect()
855 * Returns a socket connected to a local unix socket. Returns -1 on failure.
856 */
857 int
unix_connect(char * path)858 unix_connect(char *path)
859 {
860 struct sockaddr_un s_un;
861 int s, save_errno;
862
863 if (uflag) {
864 if ((s = unix_bind(unix_dg_tmp_socket, SOCK_CLOEXEC)) < 0)
865 return (-1);
866 } else {
867 if ((s = socket(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC, 0)) < 0)
868 return (-1);
869 }
870
871 memset(&s_un, 0, sizeof(struct sockaddr_un));
872 s_un.sun_family = AF_UNIX;
873
874 if (strlcpy(s_un.sun_path, path, sizeof(s_un.sun_path)) >=
875 sizeof(s_un.sun_path)) {
876 close(s);
877 errno = ENAMETOOLONG;
878 return (-1);
879 }
880 if (connect(s, (struct sockaddr *)&s_un, sizeof(s_un)) < 0) {
881 save_errno = errno;
882 close(s);
883 errno = save_errno;
884 return (-1);
885 }
886 return (s);
887
888 }
889
890 /*
891 * unix_listen()
892 * Create a unix domain socket, and listen on it.
893 */
894 int
unix_listen(char * path)895 unix_listen(char *path)
896 {
897 int s;
898 if ((s = unix_bind(path, 0)) < 0)
899 return (-1);
900
901 if (listen(s, 5) < 0) {
902 close(s);
903 return (-1);
904 }
905 return (s);
906 }
907
908 /*
909 * remote_connect()
910 * Returns a socket connected to a remote host. Properly binds to a local
911 * port or source address if needed. Returns -1 on failure.
912 */
913 int
remote_connect(const char * host,const char * port,struct addrinfo hints)914 remote_connect(const char *host, const char *port, struct addrinfo hints)
915 {
916 struct addrinfo *res, *res0;
917 int s = -1, error, save_errno;
918 #ifdef SO_BINDANY
919 int on = 1;
920 #endif
921
922 if ((error = getaddrinfo(host, port, &hints, &res0)))
923 errx(1, "getaddrinfo: %s", gai_strerror(error));
924
925 for (res = res0; res; res = res->ai_next) {
926 if ((s = socket(res->ai_family, res->ai_socktype |
927 SOCK_NONBLOCK, res->ai_protocol)) < 0)
928 continue;
929
930 /* Bind to a local port or source address if specified. */
931 if (sflag || pflag) {
932 struct addrinfo ahints, *ares;
933
934 #ifdef SO_BINDANY
935 /* try SO_BINDANY, but don't insist */
936 setsockopt(s, SOL_SOCKET, SO_BINDANY, &on, sizeof(on));
937 #endif
938 memset(&ahints, 0, sizeof(struct addrinfo));
939 ahints.ai_family = res->ai_family;
940 ahints.ai_socktype = uflag ? SOCK_DGRAM : SOCK_STREAM;
941 ahints.ai_protocol = uflag ? IPPROTO_UDP : IPPROTO_TCP;
942 ahints.ai_flags = AI_PASSIVE;
943 if ((error = getaddrinfo(sflag, pflag, &ahints, &ares)))
944 errx(1, "getaddrinfo: %s", gai_strerror(error));
945
946 if (bind(s, (struct sockaddr *)ares->ai_addr,
947 ares->ai_addrlen) < 0)
948 err(1, "bind failed");
949 freeaddrinfo(ares);
950 }
951
952 set_common_sockopts(s, res->ai_family);
953
954 if (timeout_connect(s, res->ai_addr, res->ai_addrlen) == 0)
955 break;
956 if (vflag)
957 warn("connect to %s port %s (%s) failed", host, port,
958 uflag ? "udp" : "tcp");
959
960 save_errno = errno;
961 close(s);
962 errno = save_errno;
963 s = -1;
964 }
965
966 freeaddrinfo(res0);
967
968 return (s);
969 }
970
971 int
timeout_connect(int s,const struct sockaddr * name,socklen_t namelen)972 timeout_connect(int s, const struct sockaddr *name, socklen_t namelen)
973 {
974 struct pollfd pfd;
975 socklen_t optlen;
976 int optval;
977 int ret;
978
979 if ((ret = connect(s, name, namelen)) != 0 && errno == EINPROGRESS) {
980 pfd.fd = s;
981 pfd.events = POLLOUT;
982 if ((ret = poll(&pfd, 1, timeout)) == 1) {
983 optlen = sizeof(optval);
984 if ((ret = getsockopt(s, SOL_SOCKET, SO_ERROR,
985 &optval, &optlen)) == 0) {
986 errno = optval;
987 ret = optval == 0 ? 0 : -1;
988 }
989 } else if (ret == 0) {
990 errno = ETIMEDOUT;
991 ret = -1;
992 } else
993 err(1, "poll failed");
994 }
995
996 return (ret);
997 }
998
999 /*
1000 * local_listen()
1001 * Returns a socket listening on a local port, binds to specified source
1002 * address. Returns -1 on failure.
1003 */
1004 int
local_listen(char * host,char * port,struct addrinfo hints)1005 local_listen(char *host, char *port, struct addrinfo hints)
1006 {
1007 struct addrinfo *res, *res0;
1008 int s = -1, ret, x = 1, save_errno;
1009 int error;
1010
1011 /* Allow nodename to be null. */
1012 hints.ai_flags |= AI_PASSIVE;
1013
1014 /*
1015 * In the case of binding to a wildcard address
1016 * default to binding to an ipv4 address.
1017 */
1018 if (host == NULL && hints.ai_family == AF_UNSPEC)
1019 hints.ai_family = AF_INET;
1020
1021 if ((error = getaddrinfo(host, port, &hints, &res0)))
1022 errx(1, "getaddrinfo: %s", gai_strerror(error));
1023
1024 for (res = res0; res; res = res->ai_next) {
1025 if ((s = socket(res->ai_family, res->ai_socktype,
1026 res->ai_protocol)) < 0)
1027 continue;
1028
1029 ret = setsockopt(s, SOL_SOCKET, SO_REUSEPORT, &x, sizeof(x));
1030 if (ret == -1)
1031 err(1, NULL);
1032
1033 set_common_sockopts(s, res->ai_family);
1034
1035 if (bind(s, (struct sockaddr *)res->ai_addr,
1036 res->ai_addrlen) == 0)
1037 break;
1038
1039 save_errno = errno;
1040 close(s);
1041 errno = save_errno;
1042 s = -1;
1043 }
1044
1045 if (!uflag && s != -1) {
1046 if (listen(s, 1) < 0)
1047 err(1, "listen");
1048 }
1049
1050 freeaddrinfo(res0);
1051
1052 return (s);
1053 }
1054
1055 /*
1056 * readwrite()
1057 * Loop that polls on the network file descriptor and stdin.
1058 */
1059 void
readwrite(int net_fd,struct tls * tls_ctx)1060 readwrite(int net_fd, struct tls *tls_ctx)
1061 {
1062 struct pollfd pfd[4];
1063 int stdin_fd = STDIN_FILENO;
1064 int stdout_fd = STDOUT_FILENO;
1065 unsigned char netinbuf[BUFSIZE];
1066 size_t netinbufpos = 0;
1067 unsigned char stdinbuf[BUFSIZE];
1068 size_t stdinbufpos = 0;
1069 int n, num_fds;
1070 ssize_t ret;
1071
1072 /* don't read from stdin if requested */
1073 if (dflag)
1074 stdin_fd = -1;
1075
1076 /* stdin */
1077 pfd[POLL_STDIN].fd = stdin_fd;
1078 pfd[POLL_STDIN].events = POLLIN;
1079
1080 /* network out */
1081 pfd[POLL_NETOUT].fd = net_fd;
1082 pfd[POLL_NETOUT].events = 0;
1083
1084 /* network in */
1085 pfd[POLL_NETIN].fd = net_fd;
1086 pfd[POLL_NETIN].events = POLLIN;
1087
1088 /* stdout */
1089 pfd[POLL_STDOUT].fd = stdout_fd;
1090 pfd[POLL_STDOUT].events = 0;
1091
1092 while (1) {
1093 /* both inputs are gone, buffers are empty, we are done */
1094 if (pfd[POLL_STDIN].fd == -1 && pfd[POLL_NETIN].fd == -1 &&
1095 stdinbufpos == 0 && netinbufpos == 0) {
1096 close(net_fd);
1097 return;
1098 }
1099 /* both outputs are gone, we can't continue */
1100 if (pfd[POLL_NETOUT].fd == -1 && pfd[POLL_STDOUT].fd == -1) {
1101 close(net_fd);
1102 return;
1103 }
1104 /* listen and net in gone, queues empty, done */
1105 if (lflag && pfd[POLL_NETIN].fd == -1 &&
1106 stdinbufpos == 0 && netinbufpos == 0) {
1107 close(net_fd);
1108 return;
1109 }
1110
1111 /* help says -i is for "wait between lines sent". We read and
1112 * write arbitrary amounts of data, and we don't want to start
1113 * scanning for newlines, so this is as good as it gets */
1114 if (iflag)
1115 sleep(iflag);
1116
1117 /* poll */
1118 num_fds = poll(pfd, 4, timeout);
1119
1120 /* treat poll errors */
1121 if (num_fds == -1) {
1122 close(net_fd);
1123 err(1, "polling error");
1124 }
1125
1126 /* timeout happened */
1127 if (num_fds == 0)
1128 return;
1129
1130 /* treat socket error conditions */
1131 for (n = 0; n < 4; n++) {
1132 if (pfd[n].revents & (POLLERR|POLLNVAL)) {
1133 pfd[n].fd = -1;
1134 }
1135 }
1136 /* reading is possible after HUP */
1137 if (pfd[POLL_STDIN].events & POLLIN &&
1138 pfd[POLL_STDIN].revents & POLLHUP &&
1139 !(pfd[POLL_STDIN].revents & POLLIN))
1140 pfd[POLL_STDIN].fd = -1;
1141
1142 if (pfd[POLL_NETIN].events & POLLIN &&
1143 pfd[POLL_NETIN].revents & POLLHUP &&
1144 !(pfd[POLL_NETIN].revents & POLLIN))
1145 pfd[POLL_NETIN].fd = -1;
1146
1147 if (pfd[POLL_NETOUT].revents & POLLHUP) {
1148 if (Nflag)
1149 shutdown(pfd[POLL_NETOUT].fd, SHUT_WR);
1150 pfd[POLL_NETOUT].fd = -1;
1151 }
1152 /* if HUP, stop watching stdout */
1153 if (pfd[POLL_STDOUT].revents & POLLHUP)
1154 pfd[POLL_STDOUT].fd = -1;
1155 /* if no net out, stop watching stdin */
1156 if (pfd[POLL_NETOUT].fd == -1)
1157 pfd[POLL_STDIN].fd = -1;
1158 /* if no stdout, stop watching net in */
1159 if (pfd[POLL_STDOUT].fd == -1) {
1160 if (pfd[POLL_NETIN].fd != -1)
1161 shutdown(pfd[POLL_NETIN].fd, SHUT_RD);
1162 pfd[POLL_NETIN].fd = -1;
1163 }
1164
1165 /* try to read from stdin */
1166 if (pfd[POLL_STDIN].revents & POLLIN && stdinbufpos < BUFSIZE) {
1167 ret = fillbuf(pfd[POLL_STDIN].fd, stdinbuf,
1168 &stdinbufpos, NULL);
1169 if (ret == TLS_WANT_POLLIN)
1170 pfd[POLL_STDIN].events = POLLIN;
1171 else if (ret == TLS_WANT_POLLOUT)
1172 pfd[POLL_STDIN].events = POLLOUT;
1173 else if (ret == 0 || ret == -1)
1174 pfd[POLL_STDIN].fd = -1;
1175 /* read something - poll net out */
1176 if (stdinbufpos > 0)
1177 pfd[POLL_NETOUT].events = POLLOUT;
1178 /* filled buffer - remove self from polling */
1179 if (stdinbufpos == BUFSIZE)
1180 pfd[POLL_STDIN].events = 0;
1181 }
1182 /* try to write to network */
1183 if (pfd[POLL_NETOUT].revents & POLLOUT && stdinbufpos > 0) {
1184 ret = drainbuf(pfd[POLL_NETOUT].fd, stdinbuf,
1185 &stdinbufpos, tls_ctx);
1186 if (ret == TLS_WANT_POLLIN)
1187 pfd[POLL_NETOUT].events = POLLIN;
1188 else if (ret == TLS_WANT_POLLOUT)
1189 pfd[POLL_NETOUT].events = POLLOUT;
1190 else if (ret == -1)
1191 pfd[POLL_NETOUT].fd = -1;
1192 /* buffer empty - remove self from polling */
1193 if (stdinbufpos == 0)
1194 pfd[POLL_NETOUT].events = 0;
1195 /* buffer no longer full - poll stdin again */
1196 if (stdinbufpos < BUFSIZE)
1197 pfd[POLL_STDIN].events = POLLIN;
1198 }
1199 /* try to read from network */
1200 if (pfd[POLL_NETIN].revents & POLLIN && netinbufpos < BUFSIZE) {
1201 ret = fillbuf(pfd[POLL_NETIN].fd, netinbuf,
1202 &netinbufpos, tls_ctx);
1203 if (ret == TLS_WANT_POLLIN)
1204 pfd[POLL_NETIN].events = POLLIN;
1205 else if (ret == TLS_WANT_POLLOUT)
1206 pfd[POLL_NETIN].events = POLLOUT;
1207 else if (ret == -1)
1208 pfd[POLL_NETIN].fd = -1;
1209 /* eof on net in - remove from pfd */
1210 if (ret == 0) {
1211 shutdown(pfd[POLL_NETIN].fd, SHUT_RD);
1212 pfd[POLL_NETIN].fd = -1;
1213 }
1214 /* read something - poll stdout */
1215 if (netinbufpos > 0)
1216 pfd[POLL_STDOUT].events = POLLOUT;
1217 /* filled buffer - remove self from polling */
1218 if (netinbufpos == BUFSIZE)
1219 pfd[POLL_NETIN].events = 0;
1220 /* handle telnet */
1221 if (tflag)
1222 atelnet(pfd[POLL_NETIN].fd, netinbuf,
1223 netinbufpos);
1224 }
1225 /* try to write to stdout */
1226 if (pfd[POLL_STDOUT].revents & POLLOUT && netinbufpos > 0) {
1227 ret = drainbuf(pfd[POLL_STDOUT].fd, netinbuf,
1228 &netinbufpos, NULL);
1229 if (ret == TLS_WANT_POLLIN)
1230 pfd[POLL_STDOUT].events = POLLIN;
1231 else if (ret == TLS_WANT_POLLOUT)
1232 pfd[POLL_STDOUT].events = POLLOUT;
1233 else if (ret == -1)
1234 pfd[POLL_STDOUT].fd = -1;
1235 /* buffer empty - remove self from polling */
1236 if (netinbufpos == 0)
1237 pfd[POLL_STDOUT].events = 0;
1238 /* buffer no longer full - poll net in again */
1239 if (netinbufpos < BUFSIZE)
1240 pfd[POLL_NETIN].events = POLLIN;
1241 }
1242
1243 /* stdin gone and queue empty? */
1244 if (pfd[POLL_STDIN].fd == -1 && stdinbufpos == 0) {
1245 if (pfd[POLL_NETOUT].fd != -1 && Nflag)
1246 shutdown(pfd[POLL_NETOUT].fd, SHUT_WR);
1247 pfd[POLL_NETOUT].fd = -1;
1248 }
1249 /* net in gone and queue empty? */
1250 if (pfd[POLL_NETIN].fd == -1 && netinbufpos == 0) {
1251 pfd[POLL_STDOUT].fd = -1;
1252 }
1253 }
1254 }
1255
1256 ssize_t
drainbuf(int fd,unsigned char * buf,size_t * bufpos,struct tls * tls)1257 drainbuf(int fd, unsigned char *buf, size_t *bufpos, struct tls *tls)
1258 {
1259 ssize_t n;
1260 ssize_t adjust;
1261
1262 #ifdef CRYPTO
1263 if (tls)
1264 n = tls_write(tls, buf, *bufpos);
1265 else
1266 #endif
1267 {
1268 n = write(fd, buf, *bufpos);
1269 /* don't treat EAGAIN, EINTR as error */
1270 if (n == -1 && (errno == EAGAIN || errno == EINTR))
1271 n = TLS_WANT_POLLOUT;
1272 }
1273 if (n <= 0)
1274 return n;
1275 /* adjust buffer */
1276 adjust = *bufpos - n;
1277 if (adjust > 0)
1278 memmove(buf, buf + n, adjust);
1279 *bufpos -= n;
1280 return n;
1281 }
1282
1283 ssize_t
fillbuf(int fd,unsigned char * buf,size_t * bufpos,struct tls * tls)1284 fillbuf(int fd, unsigned char *buf, size_t *bufpos, struct tls *tls)
1285 {
1286 size_t num = BUFSIZE - *bufpos;
1287 ssize_t n;
1288
1289 #ifdef CRYPTO
1290 if (tls)
1291 n = tls_read(tls, buf + *bufpos, num);
1292 else
1293 #endif
1294 {
1295
1296 n = read(fd, buf + *bufpos, num);
1297 /* don't treat EAGAIN, EINTR as error */
1298 if (n == -1 && (errno == EAGAIN || errno == EINTR))
1299 n = TLS_WANT_POLLIN;
1300 }
1301 if (n <= 0)
1302 return n;
1303 *bufpos += n;
1304 return n;
1305 }
1306
1307 /*
1308 * fdpass()
1309 * Pass the connected file descriptor to stdout and exit.
1310 */
1311 void
fdpass(int nfd)1312 fdpass(int nfd)
1313 {
1314 struct msghdr mh;
1315 union {
1316 struct cmsghdr hdr;
1317 char buf[CMSG_SPACE(sizeof(int))];
1318 } cmsgbuf;
1319 struct cmsghdr *cmsg;
1320 struct iovec iov;
1321 char c = '\0';
1322 ssize_t r;
1323 struct pollfd pfd;
1324
1325 /* Avoid obvious stupidity */
1326 if (isatty(STDOUT_FILENO))
1327 errx(1, "Cannot pass file descriptor to tty");
1328
1329 bzero(&mh, sizeof(mh));
1330 bzero(&cmsgbuf, sizeof(cmsgbuf));
1331 bzero(&iov, sizeof(iov));
1332
1333 mh.msg_control = (caddr_t)&cmsgbuf.buf;
1334 mh.msg_controllen = sizeof(cmsgbuf.buf);
1335 cmsg = CMSG_FIRSTHDR(&mh);
1336 cmsg->cmsg_len = CMSG_LEN(sizeof(int));
1337 cmsg->cmsg_level = SOL_SOCKET;
1338 cmsg->cmsg_type = SCM_RIGHTS;
1339 *(int *)CMSG_DATA(cmsg) = nfd;
1340
1341 iov.iov_base = &c;
1342 iov.iov_len = 1;
1343 mh.msg_iov = &iov;
1344 mh.msg_iovlen = 1;
1345
1346 bzero(&pfd, sizeof(pfd));
1347 pfd.fd = STDOUT_FILENO;
1348 pfd.events = POLLOUT;
1349 for (;;) {
1350 r = sendmsg(STDOUT_FILENO, &mh, 0);
1351 if (r == -1) {
1352 if (errno == EAGAIN || errno == EINTR) {
1353 if (poll(&pfd, 1, -1) == -1)
1354 err(1, "poll");
1355 continue;
1356 }
1357 err(1, "sendmsg");
1358 } else if (r != 1)
1359 errx(1, "sendmsg: unexpected return value %zd", r);
1360 else
1361 break;
1362 }
1363 exit(0);
1364 }
1365
1366 /* Deal with RFC 854 WILL/WONT DO/DONT negotiation. */
1367 void
atelnet(int nfd,unsigned char * buf,unsigned int size)1368 atelnet(int nfd, unsigned char *buf, unsigned int size)
1369 {
1370 unsigned char *p, *end;
1371 unsigned char obuf[4];
1372
1373 if (size < 3)
1374 return;
1375 end = buf + size - 2;
1376
1377 for (p = buf; p < end; p++) {
1378 if (*p != IAC)
1379 continue;
1380
1381 obuf[0] = IAC;
1382 p++;
1383 if ((*p == WILL) || (*p == WONT))
1384 obuf[1] = DONT;
1385 else if ((*p == DO) || (*p == DONT))
1386 obuf[1] = WONT;
1387 else
1388 continue;
1389
1390 p++;
1391 obuf[2] = *p;
1392 if (atomicio(vwrite, nfd, obuf, 3) != 3)
1393 warn("Write Error!");
1394 }
1395 }
1396
1397
1398 static int
strtoport(const char * portstr,int udp)1399 strtoport(const char *portstr, int udp)
1400 {
1401 struct servent *entry;
1402 int errnum;
1403 const char *proto;
1404 int port;
1405
1406 proto = udp ? "udp" : "tcp";
1407
1408 port = strtoi(portstr, NULL, 0, 1, PORT_MAX, &errnum);
1409 if (errnum == 0)
1410 return port;
1411 if ((entry = getservbyname(portstr, proto)) == NULL)
1412 errx(1, "service \"%s\" unknown", portstr);
1413 return ntohs(entry->s_port);
1414 }
1415
1416 /*
1417 * build_ports()
1418 * Build an array of ports in portlist[], listing each port
1419 * that we should try to connect to.
1420 */
1421 void
build_ports(char * p)1422 build_ports(char *p)
1423 {
1424 char *n;
1425 int hi, lo, cp;
1426 int x = 0;
1427
1428 if ((n = strchr(p, '-')) != NULL) {
1429 *n = '\0';
1430 n++;
1431
1432 /* Make sure the ports are in order: lowest->highest. */
1433 hi = strtoport(n, uflag);
1434 lo = strtoport(p, uflag);
1435 if (lo > hi) {
1436 cp = hi;
1437 hi = lo;
1438 lo = cp;
1439 }
1440
1441 /*
1442 * Initialize portlist with a random permutation. Based on
1443 * Knuth, as in ip_randomid() in sys/netinet/ip_id.c.
1444 */
1445 if (rflag) {
1446 for (x = 0; x <= hi - lo; x++) {
1447 cp = arc4random_uniform(x + 1);
1448 portlist[x] = portlist[cp];
1449 if (asprintf(&portlist[cp], "%d", x + lo) < 0)
1450 err(1, "asprintf");
1451 }
1452 } else { /* Load ports sequentially. */
1453 for (cp = lo; cp <= hi; cp++) {
1454 if (asprintf(&portlist[x], "%d", cp) < 0)
1455 err(1, "asprintf");
1456 x++;
1457 }
1458 }
1459 } else {
1460 char *tmp;
1461
1462 hi = strtoport(p, uflag);
1463 if (asprintf(&tmp, "%d", hi) != -1)
1464 portlist[0] = tmp;
1465 else
1466 err(1, NULL);
1467 }
1468 }
1469
1470 /*
1471 * udptest()
1472 * Do a few writes to see if the UDP port is there.
1473 * Fails once PF state table is full.
1474 */
1475 int
udptest(int s)1476 udptest(int s)
1477 {
1478 int i, ret;
1479
1480 for (i = 0; i <= 3; i++) {
1481 if (write(s, "X", 1) == 1)
1482 ret = 1;
1483 else
1484 ret = -1;
1485 }
1486 return (ret);
1487 }
1488
1489 void
set_common_sockopts(int s,int af)1490 set_common_sockopts(int s, int af)
1491 {
1492 int x = 1;
1493
1494 if (Sflag) {
1495 if (setsockopt(s, IPPROTO_TCP, TCP_MD5SIG,
1496 &x, sizeof(x)) == -1)
1497 err(1, NULL);
1498 }
1499 if (Dflag) {
1500 if (setsockopt(s, SOL_SOCKET, SO_DEBUG,
1501 &x, sizeof(x)) == -1)
1502 err(1, NULL);
1503 }
1504 if (Tflag != -1) {
1505 if (af == AF_INET && setsockopt(s, IPPROTO_IP,
1506 IP_TOS, &Tflag, sizeof(Tflag)) == -1)
1507 err(1, "set IP ToS");
1508
1509 else if (af == AF_INET6 && setsockopt(s, IPPROTO_IPV6,
1510 IPV6_TCLASS, &Tflag, sizeof(Tflag)) == -1)
1511 err(1, "set IPv6 traffic class");
1512 }
1513 if (Iflag) {
1514 if (setsockopt(s, SOL_SOCKET, SO_RCVBUF,
1515 &Iflag, sizeof(Iflag)) == -1)
1516 err(1, "set TCP receive buffer size");
1517 }
1518 if (Oflag) {
1519 if (setsockopt(s, SOL_SOCKET, SO_SNDBUF,
1520 &Oflag, sizeof(Oflag)) == -1)
1521 err(1, "set TCP send buffer size");
1522 }
1523
1524 if (ttl != -1) {
1525 if (af == AF_INET && setsockopt(s, IPPROTO_IP,
1526 IP_TTL, &ttl, sizeof(ttl)))
1527 err(1, "set IP TTL");
1528
1529 else if (af == AF_INET6 && setsockopt(s, IPPROTO_IPV6,
1530 IPV6_UNICAST_HOPS, &ttl, sizeof(ttl)))
1531 err(1, "set IPv6 unicast hops");
1532 }
1533
1534 if (minttl != -1) {
1535 if (af == AF_INET && setsockopt(s, IPPROTO_IP,
1536 IP_MINTTL, &minttl, sizeof(minttl)))
1537 err(1, "set IP min TTL");
1538 #ifdef IPV6_MINHOPCOUNT
1539 else if (af == AF_INET6 && setsockopt(s, IPPROTO_IPV6,
1540 IPV6_MINHOPCOUNT, &minttl, sizeof(minttl)))
1541 err(1, "set IPv6 min hop count");
1542 #endif
1543 }
1544 }
1545
1546 int
map_tos(char * s,int * val)1547 map_tos(char *s, int *val)
1548 {
1549 /* DiffServ Codepoints and other TOS mappings */
1550 const struct toskeywords {
1551 const char *keyword;
1552 int val;
1553 } *t, toskeywords[] = {
1554 { "af11", IPTOS_DSCP_AF11 },
1555 { "af12", IPTOS_DSCP_AF12 },
1556 { "af13", IPTOS_DSCP_AF13 },
1557 { "af21", IPTOS_DSCP_AF21 },
1558 { "af22", IPTOS_DSCP_AF22 },
1559 { "af23", IPTOS_DSCP_AF23 },
1560 { "af31", IPTOS_DSCP_AF31 },
1561 { "af32", IPTOS_DSCP_AF32 },
1562 { "af33", IPTOS_DSCP_AF33 },
1563 { "af41", IPTOS_DSCP_AF41 },
1564 { "af42", IPTOS_DSCP_AF42 },
1565 { "af43", IPTOS_DSCP_AF43 },
1566 { "critical", IPTOS_PREC_CRITIC_ECP },
1567 { "cs0", IPTOS_DSCP_CS0 },
1568 { "cs1", IPTOS_DSCP_CS1 },
1569 { "cs2", IPTOS_DSCP_CS2 },
1570 { "cs3", IPTOS_DSCP_CS3 },
1571 { "cs4", IPTOS_DSCP_CS4 },
1572 { "cs5", IPTOS_DSCP_CS5 },
1573 { "cs6", IPTOS_DSCP_CS6 },
1574 { "cs7", IPTOS_DSCP_CS7 },
1575 { "ef", IPTOS_DSCP_EF },
1576 { "inetcontrol", IPTOS_PREC_INTERNETCONTROL },
1577 { "lowdelay", IPTOS_LOWDELAY },
1578 { "netcontrol", IPTOS_PREC_NETCONTROL },
1579 { "reliability", IPTOS_RELIABILITY },
1580 { "throughput", IPTOS_THROUGHPUT },
1581 { NULL, -1 },
1582 };
1583
1584 for (t = toskeywords; t->keyword != NULL; t++) {
1585 if (strcmp(s, t->keyword) == 0) {
1586 *val = t->val;
1587 return (1);
1588 }
1589 }
1590
1591 return (0);
1592 }
1593
1594 #ifdef CRYPTO
1595 int
map_tls(char * s,int * val)1596 map_tls(char *s, int *val)
1597 {
1598 const struct tlskeywords {
1599 const char *keyword;
1600 int val;
1601 } *t, tlskeywords[] = {
1602 { "tlsall", TLS_ALL },
1603 { "noverify", TLS_NOVERIFY },
1604 { "noname", TLS_NONAME },
1605 { "clientcert", TLS_CCERT},
1606 { "muststaple", TLS_MUSTSTAPLE},
1607 { NULL, -1 },
1608 };
1609
1610 for (t = tlskeywords; t->keyword != NULL; t++) {
1611 if (strcmp(s, t->keyword) == 0) {
1612 *val |= t->val;
1613 return (1);
1614 }
1615 }
1616 return (0);
1617 }
1618
1619 void
report_tls(struct tls * tls_ctx,char * host,char * tlsexpectname)1620 report_tls(struct tls * tls_ctx, char * host, char *tlsexpectname)
1621 {
1622 time_t t;
1623 const char *ocsp_url;
1624
1625 fprintf(stderr, "TLS handshake negotiated %s/%s with host %s\n",
1626 tls_conn_version(tls_ctx), tls_conn_cipher(tls_ctx), host);
1627 fprintf(stderr, "Peer name: %s\n",
1628 tlsexpectname ? tlsexpectname : host);
1629 if (tls_peer_cert_subject(tls_ctx))
1630 fprintf(stderr, "Subject: %s\n",
1631 tls_peer_cert_subject(tls_ctx));
1632 if (tls_peer_cert_issuer(tls_ctx))
1633 fprintf(stderr, "Issuer: %s\n",
1634 tls_peer_cert_issuer(tls_ctx));
1635 if ((t = tls_peer_cert_notbefore(tls_ctx)) != -1)
1636 fprintf(stderr, "Valid From: %s", ctime(&t));
1637 if ((t = tls_peer_cert_notafter(tls_ctx)) != -1)
1638 fprintf(stderr, "Valid Until: %s", ctime(&t));
1639 if (tls_peer_cert_hash(tls_ctx))
1640 fprintf(stderr, "Cert Hash: %s\n",
1641 tls_peer_cert_hash(tls_ctx));
1642 ocsp_url = tls_peer_ocsp_url(tls_ctx);
1643 if (ocsp_url != NULL)
1644 fprintf(stderr, "OCSP URL: %s\n", ocsp_url);
1645 switch (tls_peer_ocsp_response_status(tls_ctx)) {
1646 case TLS_OCSP_RESPONSE_SUCCESSFUL:
1647 fprintf(stderr, "OCSP Stapling: %s\n",
1648 tls_peer_ocsp_result(tls_ctx) == NULL ? "" :
1649 tls_peer_ocsp_result(tls_ctx));
1650 fprintf(stderr,
1651 " response_status=%d cert_status=%d crl_reason=%d\n",
1652 tls_peer_ocsp_response_status(tls_ctx),
1653 tls_peer_ocsp_cert_status(tls_ctx),
1654 tls_peer_ocsp_crl_reason(tls_ctx));
1655 t = tls_peer_ocsp_this_update(tls_ctx);
1656 fprintf(stderr, " this update: %s",
1657 t != -1 ? ctime(&t) : "\n");
1658 t = tls_peer_ocsp_next_update(tls_ctx);
1659 fprintf(stderr, " next update: %s",
1660 t != -1 ? ctime(&t) : "\n");
1661 t = tls_peer_ocsp_revocation_time(tls_ctx);
1662 fprintf(stderr, " revocation: %s",
1663 t != -1 ? ctime(&t) : "\n");
1664 break;
1665 case -1:
1666 break;
1667 default:
1668 fprintf(stderr, "OCSP Stapling: failure - response_status %d (%s)\n",
1669 tls_peer_ocsp_response_status(tls_ctx),
1670 tls_peer_ocsp_result(tls_ctx) == NULL ? "" :
1671 tls_peer_ocsp_result(tls_ctx));
1672 break;
1673
1674 }
1675 }
1676 #endif
1677
1678 void
report_connect(const struct sockaddr * sa,socklen_t salen,char * path)1679 report_connect(const struct sockaddr *sa, socklen_t salen, char *path)
1680 {
1681 char remote_host[NI_MAXHOST];
1682 char remote_port[NI_MAXSERV];
1683 int herr;
1684 int flags = NI_NUMERICSERV;
1685
1686 if (path != NULL) {
1687 fprintf(stderr, "Connection on %s received!\n", path);
1688 return;
1689 }
1690
1691 if (nflag)
1692 flags |= NI_NUMERICHOST;
1693
1694 if ((herr = getnameinfo(sa, salen,
1695 remote_host, sizeof(remote_host),
1696 remote_port, sizeof(remote_port),
1697 flags)) != 0) {
1698 if (herr == EAI_SYSTEM)
1699 err(1, "getnameinfo");
1700 else
1701 errx(1, "getnameinfo: %s", gai_strerror(herr));
1702 }
1703
1704 fprintf(stderr,
1705 "Connection from %s %s "
1706 "received!\n", remote_host, remote_port);
1707 }
1708
1709 void
help(void)1710 help(void)
1711 {
1712 usage(0);
1713 fprintf(stderr, "\tCommand Summary:\n"
1714
1715 "\t-4 Use IPv4\n"
1716 "\t-6 Use IPv6\n"
1717 #ifdef CRYPTO
1718 "\t-C certfile Public key file\n"
1719 "\t-c Use TLS\n"
1720 #endif
1721 "\t-D Enable the debug socket option\n"
1722 "\t-d Detach from stdin\n"
1723 #ifdef CRYPTO
1724 "\t-e name\t Required name in peer certificate\n"
1725 #endif
1726 "\t-F Pass socket fd\n"
1727 #ifdef CRYPTO
1728 "\t-H hash\t Hash string of peer certificate\n"
1729 #endif
1730 "\t-h This help text\n"
1731 "\t-I length TCP receive buffer length\n"
1732 "\t-i interval Delay interval for lines sent, ports scanned\n"
1733 #ifdef CRYPTO
1734 "\t-K keyfile Private key file\n"
1735 #endif
1736 "\t-k Keep inbound sockets open for multiple connects\n"
1737 "\t-l Listen mode, for inbound connects\n"
1738 "\t-M ttl Outgoing TTL / Hop Limit\n"
1739 "\t-m minttl Minimum incoming TTL / Hop Limit\n"
1740 "\t-N Shutdown the network socket after EOF on stdin\n"
1741 "\t-n Suppress name/port resolutions\n"
1742 "\t-O length TCP send buffer length\n"
1743 #ifdef CRYPTO
1744 "\t-o staplefile Staple file\n"
1745 #endif
1746 "\t-P proxyuser\tUsername for proxy authentication\n"
1747 "\t-p port\t Specify local port for remote connects\n"
1748 #ifdef CRYPTO
1749 "\t-R CAfile CA bundle\n"
1750 #endif
1751 "\t-r Randomize remote ports\n"
1752 "\t-S Enable the TCP MD5 signature option\n"
1753 "\t-s source Local source address\n"
1754 #ifdef CRYPTO
1755 "\t-T keyword TOS value or TLS options\n"
1756 #endif
1757 "\t-t Answer TELNET negotiation\n"
1758 "\t-U Use UNIX domain socket\n"
1759 "\t-u UDP mode\n"
1760 #ifdef __OpenBSD__
1761 "\t-V rtable Specify alternate routing table\n"
1762 #endif
1763 "\t-v Verbose\n"
1764 "\t-w timeout Timeout for connects and final net reads\n"
1765 "\t-X proto Proxy protocol: \"4\", \"5\" (SOCKS) or \"connect\"\n"
1766 "\t-x addr[:port]\tSpecify proxy address and port\n"
1767 "\t-z Zero-I/O mode [used for scanning]\n"
1768 "Port numbers can be individual or ranges: lo-hi [inclusive]\n");
1769 exit(1);
1770 }
1771
1772 void
usage(int ret)1773 usage(int ret)
1774 {
1775 fprintf(stderr,
1776 "Usage: %s [-46%sDdFhklNnrStUuvz] [-e name] [-I length]\n"
1777 #ifdef CRYPTO
1778 "\t [-C certfile] [-H hash] [-K keyfile] [-R CAfile] "
1779 "[-T keyword] [-o staplefile]\n"
1780 #endif
1781 "\t [-i interval] [-M ttl] [-m minttl] [-O length]\n"
1782 "\t [-P proxy_username] [-p source_port]\n"
1783 "\t [-s source] "
1784 #ifdef __OpenBSD__
1785 "[-V rtable] "
1786 #endif
1787 "[-w timeout] [-X proxy_protocol]\n"
1788 "\t [-x proxy_address[:port]] [destination] [port]\n",
1789 getprogname(),
1790 #ifdef CRYPTO
1791 "c"
1792 #else
1793 ""
1794 #endif
1795 );
1796 if (ret)
1797 exit(1);
1798 }
1799