1 /* $OpenBSD: netcat.c,v 1.229 2024/11/02 17:19:27 tb Exp $ */
2 /*
3 * Copyright (c) 2001 Eric Jackson <ericj@monkey.org>
4 * Copyright (c) 2015 Bob Beck. All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 *
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. The name of the author may not be used to endorse or promote products
16 * derived from this software without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
19 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
20 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
21 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
22 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
23 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
25 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
27 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 */
29
30 /*
31 * Re-written nc(1) for OpenBSD. Original implementation by
32 * *Hobbit* <hobbit@avian.org>.
33 */
34
35 #include <sys/types.h>
36 #include <sys/socket.h>
37 #include <sys/uio.h>
38 #include <sys/un.h>
39
40 #include <netinet/in.h>
41 #include <netinet/tcp.h>
42 #include <netinet/ip.h>
43 #include <arpa/telnet.h>
44
45 #include <ctype.h>
46 #include <err.h>
47 #include <errno.h>
48 #include <limits.h>
49 #include <netdb.h>
50 #include <poll.h>
51 #include <signal.h>
52 #include <stdarg.h>
53 #include <stdio.h>
54 #include <stdlib.h>
55 #include <string.h>
56 #include <time.h>
57 #include <tls.h>
58 #include <unistd.h>
59
60 #include "atomicio.h"
61
62 #define PORT_MAX 65535
63 #define UNIX_DG_TMP_SOCKET_SIZE 19
64
65 #define POLL_STDIN 0
66 #define POLL_NETOUT 1
67 #define POLL_NETIN 2
68 #define POLL_STDOUT 3
69 #define BUFSIZE 16384
70
71 #define TLS_NOVERIFY (1 << 1)
72 #define TLS_NONAME (1 << 2)
73 #define TLS_CCERT (1 << 3)
74 #define TLS_MUSTSTAPLE (1 << 4)
75
76 /* Command Line Options */
77 int dflag; /* detached, no stdin */
78 int Fflag; /* fdpass sock to stdout */
79 unsigned int iflag; /* Interval Flag */
80 int kflag; /* More than one connect */
81 int lflag; /* Bind to local port */
82 int Nflag; /* shutdown() network socket */
83 int nflag; /* Don't do name look up */
84 char *Pflag; /* Proxy username */
85 char *pflag; /* Localport flag */
86 int rflag; /* Random ports flag */
87 char *sflag; /* Source Address */
88 int tflag; /* Telnet Emulation */
89 int uflag; /* UDP - Default to TCP */
90 int vflag; /* Verbosity */
91 int xflag; /* Socks proxy */
92 int zflag; /* Port Scan Flag */
93 int Dflag; /* sodebug */
94 int Iflag; /* TCP receive buffer size */
95 int Oflag; /* TCP send buffer size */
96 int Sflag; /* TCP MD5 signature option */
97 int Tflag = -1; /* IP Type of Service */
98 int rtableid = -1;
99
100 int usetls; /* use TLS */
101 const char *Cflag; /* Public cert file */
102 const char *Kflag; /* Private key file */
103 const char *oflag; /* OCSP stapling file */
104 const char *Rflag; /* Root CA file */
105 int tls_cachanged; /* Using non-default CA file */
106 int TLSopt; /* TLS options */
107 char *tls_expectname; /* required name in peer cert */
108 char *tls_expecthash; /* required hash of peer cert */
109 char *tls_ciphers; /* TLS ciphers */
110 char *tls_protocols; /* TLS protocols */
111 FILE *Zflag; /* file to save peer cert */
112
113 int recvcount, recvlimit;
114 int timeout = -1;
115 int family = AF_UNSPEC;
116 char *portlist[PORT_MAX+1];
117 char *unix_dg_tmp_socket;
118 int ttl = -1;
119 int minttl = -1;
120
121 void atelnet(int, unsigned char *, unsigned int);
122 int strtoport(char *portstr, int udp);
123 void build_ports(char *);
124 void help(void) __attribute__((noreturn));
125 int local_listen(const char *, const char *, struct addrinfo);
126 void readwrite(int, struct tls *);
127 void fdpass(int nfd) __attribute__((noreturn));
128 int remote_connect(const char *, const char *, struct addrinfo, char *);
129 int timeout_tls(int, struct tls *, int (*)(struct tls *));
130 int timeout_connect(int, const struct sockaddr *, socklen_t);
131 int socks_connect(const char *, const char *, struct addrinfo,
132 const char *, const char *, struct addrinfo, int, const char *);
133 int udptest(int);
134 void connection_info(const char *, const char *, const char *, const char *);
135 int unix_bind(char *, int);
136 int unix_connect(char *);
137 int unix_listen(char *);
138 void set_common_sockopts(int, int);
139 int process_tos_opt(char *, int *);
140 int process_tls_opt(char *, int *);
141 void save_peer_cert(struct tls *_tls_ctx, FILE *_fp);
142 void report_sock(const char *, const struct sockaddr *, socklen_t, char *);
143 void report_tls(struct tls *tls_ctx, char * host);
144 void usage(int);
145 ssize_t drainbuf(int, unsigned char *, size_t *, struct tls *);
146 ssize_t fillbuf(int, unsigned char *, size_t *, struct tls *);
147 void tls_setup_client(struct tls *, int, char *);
148 struct tls *tls_setup_server(struct tls *, int, char *);
149
150 int
main(int argc,char * argv[])151 main(int argc, char *argv[])
152 {
153 int ch, s = -1, ret, socksv;
154 char *host, *uport;
155 char ipaddr[NI_MAXHOST];
156 struct addrinfo hints;
157 socklen_t len;
158 struct sockaddr_storage cliaddr;
159 char *proxy = NULL, *proxyport = NULL;
160 const char *errstr;
161 struct addrinfo proxyhints;
162 char unix_dg_tmp_socket_buf[UNIX_DG_TMP_SOCKET_SIZE];
163 struct tls_config *tls_cfg = NULL;
164 struct tls *tls_ctx = NULL;
165 uint32_t protocols;
166
167 ret = 1;
168 socksv = 5;
169 host = NULL;
170 uport = NULL;
171 Rflag = tls_default_ca_cert_file();
172
173 signal(SIGPIPE, SIG_IGN);
174
175 while ((ch = getopt(argc, argv,
176 "46C:cDde:FH:hI:i:K:klM:m:NnO:o:P:p:R:rSs:T:tUuV:vW:w:X:x:Z:z"))
177 != -1) {
178 switch (ch) {
179 case '4':
180 family = AF_INET;
181 break;
182 case '6':
183 family = AF_INET6;
184 break;
185 case 'U':
186 family = AF_UNIX;
187 break;
188 case 'X':
189 if (strcasecmp(optarg, "connect") == 0)
190 socksv = -1; /* HTTP proxy CONNECT */
191 else if (strcmp(optarg, "4") == 0)
192 socksv = 4; /* SOCKS v.4 */
193 else if (strcmp(optarg, "5") == 0)
194 socksv = 5; /* SOCKS v.5 */
195 else
196 errx(1, "unsupported proxy protocol");
197 break;
198 case 'C':
199 Cflag = optarg;
200 break;
201 case 'c':
202 usetls = 1;
203 break;
204 case 'd':
205 dflag = 1;
206 break;
207 case 'e':
208 tls_expectname = optarg;
209 break;
210 case 'F':
211 Fflag = 1;
212 break;
213 case 'H':
214 tls_expecthash = optarg;
215 break;
216 case 'h':
217 help();
218 break;
219 case 'i':
220 iflag = strtonum(optarg, 0, UINT_MAX, &errstr);
221 if (errstr)
222 errx(1, "interval %s: %s", errstr, optarg);
223 break;
224 case 'K':
225 Kflag = optarg;
226 break;
227 case 'k':
228 kflag = 1;
229 break;
230 case 'l':
231 lflag = 1;
232 break;
233 case 'M':
234 ttl = strtonum(optarg, 0, 255, &errstr);
235 if (errstr)
236 errx(1, "ttl is %s", errstr);
237 break;
238 case 'm':
239 minttl = strtonum(optarg, 0, 255, &errstr);
240 if (errstr)
241 errx(1, "minttl is %s", errstr);
242 break;
243 case 'N':
244 Nflag = 1;
245 break;
246 case 'n':
247 nflag = 1;
248 break;
249 case 'P':
250 Pflag = optarg;
251 break;
252 case 'p':
253 pflag = optarg;
254 break;
255 case 'R':
256 tls_cachanged = 1;
257 Rflag = optarg;
258 break;
259 case 'r':
260 rflag = 1;
261 break;
262 case 's':
263 sflag = optarg;
264 break;
265 case 't':
266 tflag = 1;
267 break;
268 case 'u':
269 uflag = 1;
270 break;
271 case 'V':
272 rtableid = (int)strtonum(optarg, 0,
273 RT_TABLEID_MAX, &errstr);
274 if (errstr)
275 errx(1, "rtable %s: %s", errstr, optarg);
276 break;
277 case 'v':
278 vflag = 1;
279 break;
280 case 'W':
281 recvlimit = strtonum(optarg, 1, INT_MAX, &errstr);
282 if (errstr)
283 errx(1, "receive limit %s: %s", errstr, optarg);
284 break;
285 case 'w':
286 timeout = strtonum(optarg, 0, INT_MAX / 1000, &errstr);
287 if (errstr)
288 errx(1, "timeout %s: %s", errstr, optarg);
289 timeout *= 1000;
290 break;
291 case 'x':
292 xflag = 1;
293 if ((proxy = strdup(optarg)) == NULL)
294 err(1, NULL);
295 break;
296 case 'Z':
297 if (strcmp(optarg, "-") == 0)
298 Zflag = stderr;
299 else if ((Zflag = fopen(optarg, "w")) == NULL)
300 err(1, "can't open %s", optarg);
301 break;
302 case 'z':
303 zflag = 1;
304 break;
305 case 'D':
306 Dflag = 1;
307 break;
308 case 'I':
309 Iflag = strtonum(optarg, 1, 65536 << 14, &errstr);
310 if (errstr != NULL)
311 errx(1, "TCP receive window %s: %s",
312 errstr, optarg);
313 break;
314 case 'O':
315 Oflag = strtonum(optarg, 1, 65536 << 14, &errstr);
316 if (errstr != NULL)
317 errx(1, "TCP send window %s: %s",
318 errstr, optarg);
319 break;
320 case 'o':
321 oflag = optarg;
322 break;
323 case 'S':
324 Sflag = 1;
325 break;
326 case 'T':
327 errstr = NULL;
328 errno = 0;
329 if (process_tls_opt(optarg, &TLSopt))
330 break;
331 if (process_tos_opt(optarg, &Tflag))
332 break;
333 if (strlen(optarg) > 1 && optarg[0] == '0' &&
334 optarg[1] == 'x')
335 Tflag = (int)strtol(optarg, NULL, 16);
336 else
337 Tflag = (int)strtonum(optarg, 0, 255,
338 &errstr);
339 if (Tflag < 0 || Tflag > 255 || errstr || errno)
340 errx(1, "illegal tos/tls value %s", optarg);
341 break;
342 default:
343 usage(1);
344 }
345 }
346 argc -= optind;
347 argv += optind;
348
349 if (rtableid >= 0)
350 if (setrtable(rtableid) == -1)
351 err(1, "setrtable");
352
353 /* Cruft to make sure options are clean, and used properly. */
354 if (argc == 1 && family == AF_UNIX) {
355 host = argv[0];
356 } else if (argc == 1 && lflag) {
357 uport = argv[0];
358 } else if (argc == 2) {
359 host = argv[0];
360 uport = argv[1];
361 } else
362 usage(1);
363
364 if (usetls) {
365 if (Cflag && unveil(Cflag, "r") == -1)
366 err(1, "unveil %s", Cflag);
367 if (unveil(Rflag, "r") == -1)
368 err(1, "unveil %s", Rflag);
369 if (Kflag && unveil(Kflag, "r") == -1)
370 err(1, "unveil %s", Kflag);
371 if (oflag && unveil(oflag, "r") == -1)
372 err(1, "unveil %s", oflag);
373 } else if (family == AF_UNIX && uflag && lflag && !kflag) {
374 /*
375 * After recvfrom(2) from client, the server connects
376 * to the client socket. As the client path is determined
377 * during runtime, we cannot unveil(2).
378 */
379 } else {
380 if (family == AF_UNIX) {
381 if (unveil(host, "rwc") == -1)
382 err(1, "unveil %s", host);
383 if (uflag && !kflag) {
384 if (sflag) {
385 if (unveil(sflag, "rwc") == -1)
386 err(1, "unveil %s", sflag);
387 } else {
388 if (unveil("/tmp", "rwc") == -1)
389 err(1, "unveil /tmp");
390 }
391 }
392 } else {
393 /* no filesystem visibility */
394 if (unveil("/", "") == -1)
395 err(1, "unveil /");
396 }
397 }
398
399 if (family == AF_UNIX) {
400 if (pledge("stdio rpath wpath cpath tmppath unix", NULL) == -1)
401 err(1, "pledge");
402 } else if (Fflag && Pflag) {
403 if (pledge("stdio inet dns sendfd tty", NULL) == -1)
404 err(1, "pledge");
405 } else if (Fflag) {
406 if (pledge("stdio inet dns sendfd", NULL) == -1)
407 err(1, "pledge");
408 } else if (Pflag && usetls) {
409 if (pledge("stdio rpath inet dns tty", NULL) == -1)
410 err(1, "pledge");
411 } else if (Pflag) {
412 if (pledge("stdio inet dns tty", NULL) == -1)
413 err(1, "pledge");
414 } else if (usetls) {
415 if (pledge("stdio rpath inet dns", NULL) == -1)
416 err(1, "pledge");
417 } else if (pledge("stdio inet dns", NULL) == -1)
418 err(1, "pledge");
419
420 if (lflag && sflag)
421 errx(1, "cannot use -s and -l");
422 if (lflag && pflag)
423 errx(1, "cannot use -p and -l");
424 if (lflag && zflag)
425 errx(1, "cannot use -z and -l");
426 if (!lflag && kflag)
427 errx(1, "must use -l with -k");
428 if (uflag && usetls)
429 errx(1, "cannot use -c and -u");
430 if ((family == AF_UNIX) && usetls)
431 errx(1, "cannot use -c and -U");
432 if ((family == AF_UNIX) && Fflag)
433 errx(1, "cannot use -F and -U");
434 if (Fflag && usetls)
435 errx(1, "cannot use -c and -F");
436 if (TLSopt && !usetls)
437 errx(1, "you must specify -c to use TLS options");
438 if (Cflag && !usetls)
439 errx(1, "you must specify -c to use -C");
440 if (Kflag && !usetls)
441 errx(1, "you must specify -c to use -K");
442 if (Zflag && !usetls)
443 errx(1, "you must specify -c to use -Z");
444 if (oflag && !Cflag)
445 errx(1, "you must specify -C to use -o");
446 if (tls_cachanged && !usetls)
447 errx(1, "you must specify -c to use -R");
448 if (tls_expecthash && !usetls)
449 errx(1, "you must specify -c to use -H");
450 if (tls_expectname && !usetls)
451 errx(1, "you must specify -c to use -e");
452
453 /* Get name of temporary socket for unix datagram client */
454 if ((family == AF_UNIX) && uflag && !lflag) {
455 if (sflag) {
456 unix_dg_tmp_socket = sflag;
457 } else {
458 strlcpy(unix_dg_tmp_socket_buf, "/tmp/nc.XXXXXXXXXX",
459 UNIX_DG_TMP_SOCKET_SIZE);
460 if (mktemp(unix_dg_tmp_socket_buf) == NULL)
461 err(1, "mktemp");
462 unix_dg_tmp_socket = unix_dg_tmp_socket_buf;
463 }
464 }
465
466 /* Initialize addrinfo structure. */
467 if (family != AF_UNIX) {
468 memset(&hints, 0, sizeof(struct addrinfo));
469 hints.ai_family = family;
470 hints.ai_socktype = uflag ? SOCK_DGRAM : SOCK_STREAM;
471 hints.ai_protocol = uflag ? IPPROTO_UDP : IPPROTO_TCP;
472 if (nflag)
473 hints.ai_flags |= AI_NUMERICHOST;
474 }
475
476 if (xflag) {
477 if (uflag)
478 errx(1, "no proxy support for UDP mode");
479
480 if (lflag)
481 errx(1, "no proxy support for listen");
482
483 if (family == AF_UNIX)
484 errx(1, "no proxy support for unix sockets");
485
486 if (sflag)
487 errx(1, "no proxy support for local source address");
488
489 if (*proxy == '[') {
490 ++proxy;
491 proxyport = strchr(proxy, ']');
492 if (proxyport == NULL)
493 errx(1, "missing closing bracket in proxy");
494 *proxyport++ = '\0';
495 if (*proxyport == '\0')
496 /* Use default proxy port. */
497 proxyport = NULL;
498 else {
499 if (*proxyport == ':')
500 ++proxyport;
501 else
502 errx(1, "garbage proxy port delimiter");
503 }
504 } else {
505 proxyport = strrchr(proxy, ':');
506 if (proxyport != NULL)
507 *proxyport++ = '\0';
508 }
509
510 memset(&proxyhints, 0, sizeof(struct addrinfo));
511 proxyhints.ai_family = family;
512 proxyhints.ai_socktype = SOCK_STREAM;
513 proxyhints.ai_protocol = IPPROTO_TCP;
514 if (nflag)
515 proxyhints.ai_flags |= AI_NUMERICHOST;
516 }
517
518 if (usetls) {
519 if ((tls_cfg = tls_config_new()) == NULL)
520 errx(1, "unable to allocate TLS config");
521 if (Rflag && tls_config_set_ca_file(tls_cfg, Rflag) == -1)
522 errx(1, "%s", tls_config_error(tls_cfg));
523 if (Cflag && tls_config_set_cert_file(tls_cfg, Cflag) == -1)
524 errx(1, "%s", tls_config_error(tls_cfg));
525 if (Kflag && tls_config_set_key_file(tls_cfg, Kflag) == -1)
526 errx(1, "%s", tls_config_error(tls_cfg));
527 if (oflag && tls_config_set_ocsp_staple_file(tls_cfg, oflag) == -1)
528 errx(1, "%s", tls_config_error(tls_cfg));
529 if (tls_config_parse_protocols(&protocols, tls_protocols) == -1)
530 errx(1, "invalid TLS protocols `%s'", tls_protocols);
531 if (tls_config_set_protocols(tls_cfg, protocols) == -1)
532 errx(1, "%s", tls_config_error(tls_cfg));
533 if (tls_config_set_ciphers(tls_cfg, tls_ciphers) == -1)
534 errx(1, "%s", tls_config_error(tls_cfg));
535 if (!lflag && (TLSopt & TLS_CCERT))
536 errx(1, "clientcert is only valid with -l");
537 if (TLSopt & TLS_NONAME)
538 tls_config_insecure_noverifyname(tls_cfg);
539 if (TLSopt & TLS_NOVERIFY) {
540 if (tls_expecthash != NULL)
541 errx(1, "-H and -T noverify may not be used "
542 "together");
543 tls_config_insecure_noverifycert(tls_cfg);
544 }
545 if (TLSopt & TLS_MUSTSTAPLE)
546 tls_config_ocsp_require_stapling(tls_cfg);
547
548 if (Pflag) {
549 if (pledge("stdio inet dns tty", NULL) == -1)
550 err(1, "pledge");
551 } else if (pledge("stdio inet dns", NULL) == -1)
552 err(1, "pledge");
553 }
554 if (lflag) {
555 ret = 0;
556
557 if (family == AF_UNIX) {
558 if (uflag)
559 s = unix_bind(host, 0);
560 else
561 s = unix_listen(host);
562 }
563
564 if (usetls) {
565 tls_config_verify_client_optional(tls_cfg);
566 if ((tls_ctx = tls_server()) == NULL)
567 errx(1, "tls server creation failed");
568 if (tls_configure(tls_ctx, tls_cfg) == -1)
569 errx(1, "tls configuration failed (%s)",
570 tls_error(tls_ctx));
571 }
572 /* Allow only one connection at a time, but stay alive. */
573 for (;;) {
574 if (family != AF_UNIX) {
575 if (s != -1)
576 close(s);
577 s = local_listen(host, uport, hints);
578 }
579 if (s == -1)
580 err(1, NULL);
581 if (uflag && kflag) {
582 if (family == AF_UNIX) {
583 if (pledge("stdio unix", NULL) == -1)
584 err(1, "pledge");
585 }
586 /*
587 * For UDP and -k, don't connect the socket,
588 * let it receive datagrams from multiple
589 * socket pairs.
590 */
591 readwrite(s, NULL);
592 } else if (uflag && !kflag) {
593 /*
594 * For UDP and not -k, we will use recvfrom()
595 * initially to wait for a caller, then use
596 * the regular functions to talk to the caller.
597 */
598 int rv;
599 char buf[2048];
600 struct sockaddr_storage z;
601
602 len = sizeof(z);
603 rv = recvfrom(s, buf, sizeof(buf), MSG_PEEK,
604 (struct sockaddr *)&z, &len);
605 if (rv == -1)
606 err(1, "recvfrom");
607
608 rv = connect(s, (struct sockaddr *)&z, len);
609 if (rv == -1)
610 err(1, "connect");
611
612 if (family == AF_UNIX) {
613 if (pledge("stdio unix", NULL) == -1)
614 err(1, "pledge");
615 }
616 if (vflag)
617 report_sock("Connection received",
618 (struct sockaddr *)&z, len,
619 family == AF_UNIX ? host : NULL);
620
621 readwrite(s, NULL);
622 } else {
623 struct tls *tls_cctx = NULL;
624 int connfd;
625
626 len = sizeof(cliaddr);
627 connfd = accept4(s, (struct sockaddr *)&cliaddr,
628 &len, SOCK_NONBLOCK);
629 if (connfd == -1) {
630 /* For now, all errnos are fatal */
631 err(1, "accept");
632 }
633 if (vflag)
634 report_sock("Connection received",
635 (struct sockaddr *)&cliaddr, len,
636 family == AF_UNIX ? host : NULL);
637 if ((usetls) &&
638 (tls_cctx = tls_setup_server(tls_ctx, connfd, host)))
639 readwrite(connfd, tls_cctx);
640 if (!usetls)
641 readwrite(connfd, NULL);
642 if (tls_cctx)
643 timeout_tls(s, tls_cctx, tls_close);
644 close(connfd);
645 tls_free(tls_cctx);
646 }
647
648 if (!kflag)
649 break;
650 }
651 } else if (family == AF_UNIX) {
652 ret = 0;
653
654 if ((s = unix_connect(host)) > 0) {
655 if (!zflag)
656 readwrite(s, NULL);
657 close(s);
658 } else {
659 warn("%s", host);
660 ret = 1;
661 }
662
663 if (uflag)
664 unlink(unix_dg_tmp_socket);
665 return ret;
666 } else {
667 int i = 0;
668
669 /* Construct the portlist[] array. */
670 build_ports(uport);
671
672 /* Cycle through portlist, connecting to each port. */
673 for (s = -1, i = 0; portlist[i] != NULL; i++) {
674 if (s != -1)
675 close(s);
676 tls_free(tls_ctx);
677 tls_ctx = NULL;
678
679 if (usetls) {
680 if ((tls_ctx = tls_client()) == NULL)
681 errx(1, "tls client creation failed");
682 if (tls_configure(tls_ctx, tls_cfg) == -1)
683 errx(1, "tls configuration failed (%s)",
684 tls_error(tls_ctx));
685 }
686 if (xflag)
687 s = socks_connect(host, portlist[i], hints,
688 proxy, proxyport, proxyhints, socksv,
689 Pflag);
690 else
691 s = remote_connect(host, portlist[i], hints,
692 ipaddr);
693
694 if (s == -1)
695 continue;
696
697 ret = 0;
698 if (vflag || zflag) {
699 int print_info = 1;
700
701 /* For UDP, make sure we are connected. */
702 if (uflag) {
703 /* No info on failed or skipped test. */
704 if ((print_info = udptest(s)) == -1) {
705 ret = 1;
706 continue;
707 }
708 }
709 if (print_info == 1)
710 connection_info(host, portlist[i],
711 uflag ? "udp" : "tcp", ipaddr);
712 }
713 if (Fflag)
714 fdpass(s);
715 else {
716 if (usetls)
717 tls_setup_client(tls_ctx, s, host);
718 if (!zflag)
719 readwrite(s, tls_ctx);
720 if (tls_ctx)
721 timeout_tls(s, tls_ctx, tls_close);
722 }
723 }
724 }
725
726 if (s != -1)
727 close(s);
728 tls_free(tls_ctx);
729 tls_config_free(tls_cfg);
730
731 return ret;
732 }
733
734 /*
735 * unix_bind()
736 * Returns a unix socket bound to the given path
737 */
738 int
unix_bind(char * path,int flags)739 unix_bind(char *path, int flags)
740 {
741 struct sockaddr_un s_un;
742 int s, save_errno;
743
744 /* Create unix domain socket. */
745 if ((s = socket(AF_UNIX, flags | (uflag ? SOCK_DGRAM : SOCK_STREAM),
746 0)) == -1)
747 return -1;
748
749 memset(&s_un, 0, sizeof(struct sockaddr_un));
750 s_un.sun_family = AF_UNIX;
751
752 if (strlcpy(s_un.sun_path, path, sizeof(s_un.sun_path)) >=
753 sizeof(s_un.sun_path)) {
754 close(s);
755 errno = ENAMETOOLONG;
756 return -1;
757 }
758
759 if (bind(s, (struct sockaddr *)&s_un, sizeof(s_un)) == -1) {
760 save_errno = errno;
761 close(s);
762 errno = save_errno;
763 return -1;
764 }
765 if (vflag)
766 report_sock("Bound", NULL, 0, path);
767
768 return s;
769 }
770
771 int
timeout_tls(int s,struct tls * tls_ctx,int (* func)(struct tls *))772 timeout_tls(int s, struct tls *tls_ctx, int (*func)(struct tls *))
773 {
774 struct pollfd pfd;
775 int ret;
776
777 while ((ret = func(tls_ctx)) != 0) {
778 if (ret == TLS_WANT_POLLIN)
779 pfd.events = POLLIN;
780 else if (ret == TLS_WANT_POLLOUT)
781 pfd.events = POLLOUT;
782 else
783 break;
784 pfd.fd = s;
785 if ((ret = poll(&pfd, 1, timeout)) == 1)
786 continue;
787 else if (ret == 0) {
788 errno = ETIMEDOUT;
789 ret = -1;
790 break;
791 } else
792 err(1, "poll failed");
793 }
794
795 return ret;
796 }
797
798 void
tls_setup_client(struct tls * tls_ctx,int s,char * host)799 tls_setup_client(struct tls *tls_ctx, int s, char *host)
800 {
801 const char *errstr;
802
803 if (tls_connect_socket(tls_ctx, s,
804 tls_expectname ? tls_expectname : host) == -1) {
805 errx(1, "tls connection failed (%s)",
806 tls_error(tls_ctx));
807 }
808 if (timeout_tls(s, tls_ctx, tls_handshake) == -1) {
809 if ((errstr = tls_error(tls_ctx)) == NULL)
810 errstr = strerror(errno);
811 errx(1, "tls handshake failed (%s)", errstr);
812 }
813 if (vflag)
814 report_tls(tls_ctx, host);
815 if (tls_expecthash && (tls_peer_cert_hash(tls_ctx) == NULL ||
816 strcmp(tls_expecthash, tls_peer_cert_hash(tls_ctx)) != 0))
817 errx(1, "peer certificate is not %s", tls_expecthash);
818 if (Zflag) {
819 save_peer_cert(tls_ctx, Zflag);
820 if (Zflag != stderr && (fclose(Zflag) != 0))
821 err(1, "fclose failed saving peer cert");
822 }
823 }
824
825 struct tls *
tls_setup_server(struct tls * tls_ctx,int connfd,char * host)826 tls_setup_server(struct tls *tls_ctx, int connfd, char *host)
827 {
828 struct tls *tls_cctx;
829 const char *errstr;
830
831 if (tls_accept_socket(tls_ctx, &tls_cctx, connfd) == -1) {
832 warnx("tls accept failed (%s)", tls_error(tls_ctx));
833 } else if (timeout_tls(connfd, tls_cctx, tls_handshake) == -1) {
834 if ((errstr = tls_error(tls_cctx)) == NULL)
835 errstr = strerror(errno);
836 warnx("tls handshake failed (%s)", errstr);
837 } else {
838 int gotcert = tls_peer_cert_provided(tls_cctx);
839
840 if (vflag && gotcert)
841 report_tls(tls_cctx, host);
842 if ((TLSopt & TLS_CCERT) && !gotcert)
843 warnx("No client certificate provided");
844 else if (gotcert && tls_expecthash &&
845 (tls_peer_cert_hash(tls_cctx) == NULL ||
846 strcmp(tls_expecthash, tls_peer_cert_hash(tls_cctx)) != 0))
847 warnx("peer certificate is not %s", tls_expecthash);
848 else if (gotcert && tls_expectname &&
849 (!tls_peer_cert_contains_name(tls_cctx, tls_expectname)))
850 warnx("name (%s) not found in client cert",
851 tls_expectname);
852 else {
853 return tls_cctx;
854 }
855 }
856 return NULL;
857 }
858
859 /*
860 * unix_connect()
861 * Returns a socket connected to a local unix socket. Returns -1 on failure.
862 */
863 int
unix_connect(char * path)864 unix_connect(char *path)
865 {
866 struct sockaddr_un s_un;
867 int s, save_errno;
868
869 if (uflag) {
870 if ((s = unix_bind(unix_dg_tmp_socket, SOCK_CLOEXEC)) == -1)
871 return -1;
872 } else {
873 if ((s = socket(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC, 0)) == -1)
874 return -1;
875 }
876
877 memset(&s_un, 0, sizeof(struct sockaddr_un));
878 s_un.sun_family = AF_UNIX;
879
880 if (strlcpy(s_un.sun_path, path, sizeof(s_un.sun_path)) >=
881 sizeof(s_un.sun_path)) {
882 close(s);
883 errno = ENAMETOOLONG;
884 return -1;
885 }
886 if (connect(s, (struct sockaddr *)&s_un, sizeof(s_un)) == -1) {
887 save_errno = errno;
888 close(s);
889 errno = save_errno;
890 return -1;
891 }
892 return s;
893 }
894
895 /*
896 * unix_listen()
897 * Create a unix domain socket, and listen on it.
898 */
899 int
unix_listen(char * path)900 unix_listen(char *path)
901 {
902 int s;
903
904 if ((s = unix_bind(path, 0)) == -1)
905 return -1;
906 if (listen(s, 5) == -1) {
907 close(s);
908 return -1;
909 }
910 if (vflag)
911 report_sock("Listening", NULL, 0, path);
912
913 return s;
914 }
915
916 /*
917 * remote_connect()
918 * Returns a socket connected to a remote host. Properly binds to a local
919 * port or source address if needed. Returns -1 on failure.
920 */
921 int
remote_connect(const char * host,const char * port,struct addrinfo hints,char * ipaddr)922 remote_connect(const char *host, const char *port, struct addrinfo hints,
923 char *ipaddr)
924 {
925 struct addrinfo *res, *res0;
926 int s = -1, error, herr, on = 1, save_errno;
927
928 if ((error = getaddrinfo(host, port, &hints, &res0)))
929 errx(1, "getaddrinfo for host \"%s\" port %s: %s", host,
930 port, gai_strerror(error));
931
932 for (res = res0; res; res = res->ai_next) {
933 if ((s = socket(res->ai_family, res->ai_socktype |
934 SOCK_NONBLOCK, res->ai_protocol)) == -1)
935 continue;
936
937 /* Bind to a local port or source address if specified. */
938 if (sflag || pflag) {
939 struct addrinfo ahints, *ares;
940
941 /* try SO_BINDANY, but don't insist */
942 setsockopt(s, SOL_SOCKET, SO_BINDANY, &on, sizeof(on));
943 memset(&ahints, 0, sizeof(struct addrinfo));
944 ahints.ai_family = res->ai_family;
945 ahints.ai_socktype = uflag ? SOCK_DGRAM : SOCK_STREAM;
946 ahints.ai_protocol = uflag ? IPPROTO_UDP : IPPROTO_TCP;
947 ahints.ai_flags = AI_PASSIVE;
948 if ((error = getaddrinfo(sflag, pflag, &ahints, &ares)))
949 errx(1, "getaddrinfo: %s", gai_strerror(error));
950
951 if (bind(s, (struct sockaddr *)ares->ai_addr,
952 ares->ai_addrlen) == -1)
953 err(1, "bind failed");
954 freeaddrinfo(ares);
955 }
956
957 set_common_sockopts(s, res->ai_family);
958
959 if (ipaddr != NULL) {
960 herr = getnameinfo(res->ai_addr, res->ai_addrlen,
961 ipaddr, NI_MAXHOST, NULL, 0, NI_NUMERICHOST);
962 switch (herr) {
963 case 0:
964 break;
965 case EAI_SYSTEM:
966 err(1, "getnameinfo");
967 default:
968 errx(1, "getnameinfo: %s", gai_strerror(herr));
969 }
970 }
971
972 if (timeout_connect(s, res->ai_addr, res->ai_addrlen) == 0)
973 break;
974
975 if (vflag) {
976 /* only print IP if there is something to report */
977 if (nflag || ipaddr == NULL ||
978 (strncmp(host, ipaddr, NI_MAXHOST) == 0))
979 warn("connect to %s port %s (%s) failed", host,
980 port, uflag ? "udp" : "tcp");
981 else
982 warn("connect to %s (%s) port %s (%s) failed",
983 host, ipaddr, port, uflag ? "udp" : "tcp");
984 }
985
986 save_errno = errno;
987 close(s);
988 errno = save_errno;
989 s = -1;
990 }
991
992 freeaddrinfo(res0);
993
994 return s;
995 }
996
997 int
timeout_connect(int s,const struct sockaddr * name,socklen_t namelen)998 timeout_connect(int s, const struct sockaddr *name, socklen_t namelen)
999 {
1000 struct pollfd pfd;
1001 socklen_t optlen;
1002 int optval;
1003 int ret;
1004
1005 if ((ret = connect(s, name, namelen)) != 0 && errno == EINPROGRESS) {
1006 pfd.fd = s;
1007 pfd.events = POLLOUT;
1008 if ((ret = poll(&pfd, 1, timeout)) == 1) {
1009 optlen = sizeof(optval);
1010 if ((ret = getsockopt(s, SOL_SOCKET, SO_ERROR,
1011 &optval, &optlen)) == 0) {
1012 errno = optval;
1013 ret = optval == 0 ? 0 : -1;
1014 }
1015 } else if (ret == 0) {
1016 errno = ETIMEDOUT;
1017 ret = -1;
1018 } else
1019 err(1, "poll failed");
1020 }
1021
1022 return ret;
1023 }
1024
1025 /*
1026 * local_listen()
1027 * Returns a socket listening on a local port, binds to specified source
1028 * address. Returns -1 on failure.
1029 */
1030 int
local_listen(const char * host,const char * port,struct addrinfo hints)1031 local_listen(const char *host, const char *port, struct addrinfo hints)
1032 {
1033 struct addrinfo *res, *res0;
1034 int s = -1, ret, x = 1, save_errno;
1035 int error;
1036
1037 /* Allow nodename to be null. */
1038 hints.ai_flags |= AI_PASSIVE;
1039
1040 /*
1041 * In the case of binding to a wildcard address
1042 * default to binding to an ipv4 address.
1043 */
1044 if (host == NULL && hints.ai_family == AF_UNSPEC)
1045 hints.ai_family = AF_INET;
1046
1047 if ((error = getaddrinfo(host, port, &hints, &res0)))
1048 errx(1, "getaddrinfo: %s", gai_strerror(error));
1049
1050 for (res = res0; res; res = res->ai_next) {
1051 if ((s = socket(res->ai_family, res->ai_socktype,
1052 res->ai_protocol)) == -1)
1053 continue;
1054
1055 ret = setsockopt(s, SOL_SOCKET, SO_REUSEPORT, &x, sizeof(x));
1056 if (ret == -1)
1057 err(1, NULL);
1058
1059 set_common_sockopts(s, res->ai_family);
1060
1061 if (bind(s, (struct sockaddr *)res->ai_addr,
1062 res->ai_addrlen) == 0)
1063 break;
1064
1065 save_errno = errno;
1066 close(s);
1067 errno = save_errno;
1068 s = -1;
1069 }
1070
1071 if (!uflag && s != -1) {
1072 if (listen(s, 1) == -1)
1073 err(1, "listen");
1074 }
1075 if (vflag && s != -1) {
1076 struct sockaddr_storage ss;
1077 socklen_t len;
1078
1079 len = sizeof(ss);
1080 if (getsockname(s, (struct sockaddr *)&ss, &len) == -1)
1081 err(1, "getsockname");
1082 report_sock(uflag ? "Bound" : "Listening",
1083 (struct sockaddr *)&ss, len, NULL);
1084 }
1085
1086 freeaddrinfo(res0);
1087
1088 return s;
1089 }
1090
1091 /*
1092 * readwrite()
1093 * Loop that polls on the network file descriptor and stdin.
1094 */
1095 void
readwrite(int net_fd,struct tls * tls_ctx)1096 readwrite(int net_fd, struct tls *tls_ctx)
1097 {
1098 struct pollfd pfd[4];
1099 int stdin_fd = STDIN_FILENO;
1100 int stdout_fd = STDOUT_FILENO;
1101 unsigned char netinbuf[BUFSIZE];
1102 size_t netinbufpos = 0;
1103 unsigned char stdinbuf[BUFSIZE];
1104 size_t stdinbufpos = 0;
1105 int n, num_fds;
1106 ssize_t ret;
1107
1108 /* don't read from stdin if requested */
1109 if (dflag)
1110 stdin_fd = -1;
1111
1112 /* stdin */
1113 pfd[POLL_STDIN].fd = stdin_fd;
1114 pfd[POLL_STDIN].events = POLLIN;
1115
1116 /* network out */
1117 pfd[POLL_NETOUT].fd = net_fd;
1118 pfd[POLL_NETOUT].events = 0;
1119
1120 /* network in */
1121 pfd[POLL_NETIN].fd = net_fd;
1122 pfd[POLL_NETIN].events = POLLIN;
1123
1124 /* stdout */
1125 pfd[POLL_STDOUT].fd = stdout_fd;
1126 pfd[POLL_STDOUT].events = 0;
1127
1128 while (1) {
1129 /* both inputs are gone, buffers are empty, we are done */
1130 if (pfd[POLL_STDIN].fd == -1 && pfd[POLL_NETIN].fd == -1 &&
1131 stdinbufpos == 0 && netinbufpos == 0)
1132 return;
1133 /* both outputs are gone, we can't continue */
1134 if (pfd[POLL_NETOUT].fd == -1 && pfd[POLL_STDOUT].fd == -1)
1135 return;
1136 /* listen and net in gone, queues empty, done */
1137 if (lflag && pfd[POLL_NETIN].fd == -1 &&
1138 stdinbufpos == 0 && netinbufpos == 0)
1139 return;
1140
1141 /* help says -i is for "wait between lines sent". We read and
1142 * write arbitrary amounts of data, and we don't want to start
1143 * scanning for newlines, so this is as good as it gets */
1144 if (iflag)
1145 sleep(iflag);
1146
1147 /* poll */
1148 num_fds = poll(pfd, 4, timeout);
1149
1150 /* treat poll errors */
1151 if (num_fds == -1)
1152 err(1, "polling error");
1153
1154 /* timeout happened */
1155 if (num_fds == 0)
1156 return;
1157
1158 /* treat socket error conditions */
1159 for (n = 0; n < 4; n++) {
1160 if (pfd[n].revents & (POLLERR|POLLNVAL)) {
1161 pfd[n].fd = -1;
1162 }
1163 }
1164 /* reading is possible after HUP */
1165 if (pfd[POLL_STDIN].events & POLLIN &&
1166 pfd[POLL_STDIN].revents & POLLHUP &&
1167 !(pfd[POLL_STDIN].revents & POLLIN))
1168 pfd[POLL_STDIN].fd = -1;
1169
1170 if (pfd[POLL_NETIN].events & POLLIN &&
1171 pfd[POLL_NETIN].revents & POLLHUP &&
1172 !(pfd[POLL_NETIN].revents & POLLIN))
1173 pfd[POLL_NETIN].fd = -1;
1174
1175 if (pfd[POLL_NETOUT].revents & POLLHUP) {
1176 if (pfd[POLL_NETOUT].fd != -1 && Nflag)
1177 shutdown(pfd[POLL_NETOUT].fd, SHUT_WR);
1178 pfd[POLL_NETOUT].fd = -1;
1179 }
1180 /* if HUP, stop watching stdout */
1181 if (pfd[POLL_STDOUT].revents & POLLHUP)
1182 pfd[POLL_STDOUT].fd = -1;
1183 /* if no net out, stop watching stdin */
1184 if (pfd[POLL_NETOUT].fd == -1)
1185 pfd[POLL_STDIN].fd = -1;
1186 /* if no stdout, stop watching net in */
1187 if (pfd[POLL_STDOUT].fd == -1) {
1188 if (pfd[POLL_NETIN].fd != -1)
1189 shutdown(pfd[POLL_NETIN].fd, SHUT_RD);
1190 pfd[POLL_NETIN].fd = -1;
1191 }
1192
1193 /* try to read from stdin */
1194 if (pfd[POLL_STDIN].revents & POLLIN && stdinbufpos < BUFSIZE) {
1195 ret = fillbuf(pfd[POLL_STDIN].fd, stdinbuf,
1196 &stdinbufpos, NULL);
1197 if (ret == TLS_WANT_POLLIN)
1198 pfd[POLL_STDIN].events = POLLIN;
1199 else if (ret == TLS_WANT_POLLOUT)
1200 pfd[POLL_STDIN].events = POLLOUT;
1201 else if (ret == 0 || ret == -1)
1202 pfd[POLL_STDIN].fd = -1;
1203 /* read something - poll net out */
1204 if (stdinbufpos > 0)
1205 pfd[POLL_NETOUT].events = POLLOUT;
1206 /* filled buffer - remove self from polling */
1207 if (stdinbufpos == BUFSIZE)
1208 pfd[POLL_STDIN].events = 0;
1209 }
1210 /* try to write to network */
1211 if (pfd[POLL_NETOUT].revents & POLLOUT && stdinbufpos > 0) {
1212 ret = drainbuf(pfd[POLL_NETOUT].fd, stdinbuf,
1213 &stdinbufpos, tls_ctx);
1214 if (ret == TLS_WANT_POLLIN)
1215 pfd[POLL_NETOUT].events = POLLIN;
1216 else if (ret == TLS_WANT_POLLOUT)
1217 pfd[POLL_NETOUT].events = POLLOUT;
1218 else if (ret == -1)
1219 pfd[POLL_NETOUT].fd = -1;
1220 /* buffer empty - remove self from polling */
1221 if (stdinbufpos == 0)
1222 pfd[POLL_NETOUT].events = 0;
1223 /* buffer no longer full - poll stdin again */
1224 if (stdinbufpos < BUFSIZE)
1225 pfd[POLL_STDIN].events = POLLIN;
1226 }
1227 /* try to read from network */
1228 if (pfd[POLL_NETIN].revents & POLLIN && netinbufpos < BUFSIZE) {
1229 ret = fillbuf(pfd[POLL_NETIN].fd, netinbuf,
1230 &netinbufpos, tls_ctx);
1231 if (ret == TLS_WANT_POLLIN)
1232 pfd[POLL_NETIN].events = POLLIN;
1233 else if (ret == TLS_WANT_POLLOUT)
1234 pfd[POLL_NETIN].events = POLLOUT;
1235 else if (ret == -1)
1236 pfd[POLL_NETIN].fd = -1;
1237 /* eof on net in - remove from pfd */
1238 if (ret == 0) {
1239 shutdown(pfd[POLL_NETIN].fd, SHUT_RD);
1240 pfd[POLL_NETIN].fd = -1;
1241 }
1242 if (recvlimit > 0 && ++recvcount >= recvlimit) {
1243 if (pfd[POLL_NETIN].fd != -1)
1244 shutdown(pfd[POLL_NETIN].fd, SHUT_RD);
1245 pfd[POLL_NETIN].fd = -1;
1246 pfd[POLL_STDIN].fd = -1;
1247 }
1248 /* read something - poll stdout */
1249 if (netinbufpos > 0)
1250 pfd[POLL_STDOUT].events = POLLOUT;
1251 /* filled buffer - remove self from polling */
1252 if (netinbufpos == BUFSIZE)
1253 pfd[POLL_NETIN].events = 0;
1254 /* handle telnet */
1255 if (pfd[POLL_NETIN].fd != -1 && tflag)
1256 atelnet(pfd[POLL_NETIN].fd, netinbuf,
1257 netinbufpos);
1258 }
1259 /* try to write to stdout */
1260 if (pfd[POLL_STDOUT].revents & POLLOUT && netinbufpos > 0) {
1261 ret = drainbuf(pfd[POLL_STDOUT].fd, netinbuf,
1262 &netinbufpos, NULL);
1263 if (ret == TLS_WANT_POLLIN)
1264 pfd[POLL_STDOUT].events = POLLIN;
1265 else if (ret == TLS_WANT_POLLOUT)
1266 pfd[POLL_STDOUT].events = POLLOUT;
1267 else if (ret == -1)
1268 pfd[POLL_STDOUT].fd = -1;
1269 /* buffer empty - remove self from polling */
1270 if (netinbufpos == 0)
1271 pfd[POLL_STDOUT].events = 0;
1272 /* buffer no longer full - poll net in again */
1273 if (netinbufpos < BUFSIZE)
1274 pfd[POLL_NETIN].events = POLLIN;
1275 }
1276
1277 /* stdin gone and queue empty? */
1278 if (pfd[POLL_STDIN].fd == -1 && stdinbufpos == 0) {
1279 if (pfd[POLL_NETOUT].fd != -1 && Nflag)
1280 shutdown(pfd[POLL_NETOUT].fd, SHUT_WR);
1281 pfd[POLL_NETOUT].fd = -1;
1282 }
1283 /* net in gone and queue empty? */
1284 if (pfd[POLL_NETIN].fd == -1 && netinbufpos == 0) {
1285 pfd[POLL_STDOUT].fd = -1;
1286 }
1287 }
1288 }
1289
1290 ssize_t
drainbuf(int fd,unsigned char * buf,size_t * bufpos,struct tls * tls)1291 drainbuf(int fd, unsigned char *buf, size_t *bufpos, struct tls *tls)
1292 {
1293 ssize_t n;
1294 ssize_t adjust;
1295
1296 if (fd == -1)
1297 return -1;
1298
1299 if (tls) {
1300 n = tls_write(tls, buf, *bufpos);
1301 if (n == -1)
1302 errx(1, "tls write failed (%s)", tls_error(tls));
1303 } else {
1304 n = write(fd, buf, *bufpos);
1305 /* don't treat EAGAIN, EINTR as error */
1306 if (n == -1 && (errno == EAGAIN || errno == EINTR))
1307 n = TLS_WANT_POLLOUT;
1308 }
1309 if (n <= 0)
1310 return n;
1311 /* adjust buffer */
1312 adjust = *bufpos - n;
1313 if (adjust > 0)
1314 memmove(buf, buf + n, adjust);
1315 *bufpos -= n;
1316 return n;
1317 }
1318
1319 ssize_t
fillbuf(int fd,unsigned char * buf,size_t * bufpos,struct tls * tls)1320 fillbuf(int fd, unsigned char *buf, size_t *bufpos, struct tls *tls)
1321 {
1322 size_t num = BUFSIZE - *bufpos;
1323 ssize_t n;
1324
1325 if (fd == -1)
1326 return -1;
1327
1328 if (tls) {
1329 n = tls_read(tls, buf + *bufpos, num);
1330 if (n == -1)
1331 errx(1, "tls read failed (%s)", tls_error(tls));
1332 } else {
1333 n = read(fd, buf + *bufpos, num);
1334 /* don't treat EAGAIN, EINTR as error */
1335 if (n == -1 && (errno == EAGAIN || errno == EINTR))
1336 n = TLS_WANT_POLLIN;
1337 }
1338 if (n <= 0)
1339 return n;
1340 *bufpos += n;
1341 return n;
1342 }
1343
1344 /*
1345 * fdpass()
1346 * Pass the connected file descriptor to stdout and exit.
1347 */
1348 void
fdpass(int nfd)1349 fdpass(int nfd)
1350 {
1351 struct msghdr mh;
1352 union {
1353 struct cmsghdr hdr;
1354 char buf[CMSG_SPACE(sizeof(int))];
1355 } cmsgbuf;
1356 struct cmsghdr *cmsg;
1357 struct iovec iov;
1358 char c = '\0';
1359 ssize_t r;
1360 struct pollfd pfd;
1361
1362 /* Avoid obvious stupidity */
1363 if (isatty(STDOUT_FILENO))
1364 errx(1, "Cannot pass file descriptor to tty");
1365
1366 memset(&mh, 0, sizeof(mh));
1367 memset(&cmsgbuf, 0, sizeof(cmsgbuf));
1368 memset(&iov, 0, sizeof(iov));
1369
1370 mh.msg_control = &cmsgbuf.buf;
1371 mh.msg_controllen = sizeof(cmsgbuf.buf);
1372 cmsg = CMSG_FIRSTHDR(&mh);
1373 cmsg->cmsg_len = CMSG_LEN(sizeof(int));
1374 cmsg->cmsg_level = SOL_SOCKET;
1375 cmsg->cmsg_type = SCM_RIGHTS;
1376 *(int *)CMSG_DATA(cmsg) = nfd;
1377
1378 iov.iov_base = &c;
1379 iov.iov_len = 1;
1380 mh.msg_iov = &iov;
1381 mh.msg_iovlen = 1;
1382
1383 memset(&pfd, 0, sizeof(pfd));
1384 pfd.fd = STDOUT_FILENO;
1385 pfd.events = POLLOUT;
1386 for (;;) {
1387 r = sendmsg(STDOUT_FILENO, &mh, 0);
1388 if (r == -1) {
1389 if (errno == EAGAIN || errno == EINTR) {
1390 if (poll(&pfd, 1, -1) == -1)
1391 err(1, "poll");
1392 continue;
1393 }
1394 err(1, "sendmsg");
1395 } else if (r != 1)
1396 errx(1, "sendmsg: unexpected return value %zd", r);
1397 else
1398 break;
1399 }
1400 exit(0);
1401 }
1402
1403 /* Deal with RFC 854 WILL/WONT DO/DONT negotiation. */
1404 void
atelnet(int nfd,unsigned char * buf,unsigned int size)1405 atelnet(int nfd, unsigned char *buf, unsigned int size)
1406 {
1407 unsigned char *p, *end;
1408 unsigned char obuf[4];
1409
1410 if (size < 3)
1411 return;
1412 end = buf + size - 2;
1413
1414 for (p = buf; p < end; p++) {
1415 if (*p != IAC)
1416 continue;
1417
1418 obuf[0] = IAC;
1419 p++;
1420 if ((*p == WILL) || (*p == WONT))
1421 obuf[1] = DONT;
1422 else if ((*p == DO) || (*p == DONT))
1423 obuf[1] = WONT;
1424 else
1425 continue;
1426
1427 p++;
1428 obuf[2] = *p;
1429 if (atomicio(vwrite, nfd, obuf, 3) != 3)
1430 warn("Write Error!");
1431 }
1432 }
1433
1434 int
strtoport(char * portstr,int udp)1435 strtoport(char *portstr, int udp)
1436 {
1437 struct servent *entry;
1438 const char *errstr;
1439 char *proto;
1440 int port = -1;
1441
1442 proto = udp ? "udp" : "tcp";
1443
1444 port = strtonum(portstr, 1, PORT_MAX, &errstr);
1445 if (errstr == NULL)
1446 return port;
1447 if (errno != EINVAL)
1448 errx(1, "port number %s: %s", errstr, portstr);
1449 if ((entry = getservbyname(portstr, proto)) == NULL)
1450 errx(1, "service \"%s\" unknown", portstr);
1451 return ntohs(entry->s_port);
1452 }
1453
1454 /*
1455 * build_ports()
1456 * Build an array of ports in portlist[], listing each port
1457 * that we should try to connect to.
1458 */
1459 void
build_ports(char * p)1460 build_ports(char *p)
1461 {
1462 char *n;
1463 int hi, lo, cp;
1464 int x = 0;
1465
1466 if (isdigit((unsigned char)*p) && (n = strchr(p, '-')) != NULL) {
1467 *n = '\0';
1468 n++;
1469
1470 /* Make sure the ports are in order: lowest->highest. */
1471 hi = strtoport(n, uflag);
1472 lo = strtoport(p, uflag);
1473 if (lo > hi) {
1474 cp = hi;
1475 hi = lo;
1476 lo = cp;
1477 }
1478
1479 /*
1480 * Initialize portlist with a random permutation. Based on
1481 * Knuth, as in ip_randomid() in sys/netinet/ip_id.c.
1482 */
1483 if (rflag) {
1484 for (x = 0; x <= hi - lo; x++) {
1485 cp = arc4random_uniform(x + 1);
1486 portlist[x] = portlist[cp];
1487 if (asprintf(&portlist[cp], "%d", x + lo) == -1)
1488 err(1, "asprintf");
1489 }
1490 } else { /* Load ports sequentially. */
1491 for (cp = lo; cp <= hi; cp++) {
1492 if (asprintf(&portlist[x], "%d", cp) == -1)
1493 err(1, "asprintf");
1494 x++;
1495 }
1496 }
1497 } else {
1498 char *tmp;
1499
1500 hi = strtoport(p, uflag);
1501 if (asprintf(&tmp, "%d", hi) != -1)
1502 portlist[0] = tmp;
1503 else
1504 err(1, NULL);
1505 }
1506 }
1507
1508 /*
1509 * udptest()
1510 * Do a few writes to see if the UDP port is there.
1511 * Fails once PF state table is full.
1512 */
1513 int
udptest(int s)1514 udptest(int s)
1515 {
1516 int i, ret;
1517
1518 /* Only write to the socket in scan mode or interactive mode. */
1519 if (!zflag && !isatty(STDIN_FILENO))
1520 return 0;
1521
1522 for (i = 0; i <= 3; i++) {
1523 if (write(s, "X", 1) == 1)
1524 ret = 1;
1525 else
1526 ret = -1;
1527 }
1528 return ret;
1529 }
1530
1531 void
connection_info(const char * host,const char * port,const char * proto,const char * ipaddr)1532 connection_info(const char *host, const char *port, const char *proto,
1533 const char *ipaddr)
1534 {
1535 struct servent *sv;
1536 char *service = "*";
1537
1538 /* Look up service name unless -n. */
1539 if (!nflag) {
1540 sv = getservbyport(ntohs(atoi(port)), proto);
1541 if (sv != NULL)
1542 service = sv->s_name;
1543 }
1544
1545 fprintf(stderr, "Connection to %s", host);
1546
1547 /*
1548 * if we aren't connecting thru a proxy and
1549 * there is something to report, print IP
1550 */
1551 if (!nflag && !xflag && strcmp(host, ipaddr) != 0)
1552 fprintf(stderr, " (%s)", ipaddr);
1553
1554 fprintf(stderr, " %s port [%s/%s] succeeded!\n", port, proto, service);
1555 }
1556
1557 void
set_common_sockopts(int s,int af)1558 set_common_sockopts(int s, int af)
1559 {
1560 int x = 1;
1561
1562 if (Sflag) {
1563 if (setsockopt(s, IPPROTO_TCP, TCP_MD5SIG,
1564 &x, sizeof(x)) == -1)
1565 err(1, NULL);
1566 }
1567 if (Dflag) {
1568 if (setsockopt(s, SOL_SOCKET, SO_DEBUG,
1569 &x, sizeof(x)) == -1)
1570 err(1, NULL);
1571 }
1572 if (Tflag != -1) {
1573 if (af == AF_INET && setsockopt(s, IPPROTO_IP,
1574 IP_TOS, &Tflag, sizeof(Tflag)) == -1)
1575 err(1, "set IP ToS");
1576
1577 else if (af == AF_INET6 && setsockopt(s, IPPROTO_IPV6,
1578 IPV6_TCLASS, &Tflag, sizeof(Tflag)) == -1)
1579 err(1, "set IPv6 traffic class");
1580 }
1581 if (Iflag) {
1582 if (setsockopt(s, SOL_SOCKET, SO_RCVBUF,
1583 &Iflag, sizeof(Iflag)) == -1)
1584 err(1, "set TCP receive buffer size");
1585 }
1586 if (Oflag) {
1587 if (setsockopt(s, SOL_SOCKET, SO_SNDBUF,
1588 &Oflag, sizeof(Oflag)) == -1)
1589 err(1, "set TCP send buffer size");
1590 }
1591
1592 if (ttl != -1) {
1593 if (af == AF_INET && setsockopt(s, IPPROTO_IP,
1594 IP_TTL, &ttl, sizeof(ttl)))
1595 err(1, "set IP TTL");
1596
1597 else if (af == AF_INET6 && setsockopt(s, IPPROTO_IPV6,
1598 IPV6_UNICAST_HOPS, &ttl, sizeof(ttl)))
1599 err(1, "set IPv6 unicast hops");
1600 }
1601
1602 if (minttl != -1) {
1603 if (af == AF_INET && setsockopt(s, IPPROTO_IP,
1604 IP_MINTTL, &minttl, sizeof(minttl)))
1605 err(1, "set IP min TTL");
1606
1607 else if (af == AF_INET6 && setsockopt(s, IPPROTO_IPV6,
1608 IPV6_MINHOPCOUNT, &minttl, sizeof(minttl)))
1609 err(1, "set IPv6 min hop count");
1610 }
1611 }
1612
1613 int
process_tos_opt(char * s,int * val)1614 process_tos_opt(char *s, int *val)
1615 {
1616 /* DiffServ Codepoints and other TOS mappings */
1617 const struct toskeywords {
1618 const char *keyword;
1619 int val;
1620 } *t, toskeywords[] = {
1621 { "af11", IPTOS_DSCP_AF11 },
1622 { "af12", IPTOS_DSCP_AF12 },
1623 { "af13", IPTOS_DSCP_AF13 },
1624 { "af21", IPTOS_DSCP_AF21 },
1625 { "af22", IPTOS_DSCP_AF22 },
1626 { "af23", IPTOS_DSCP_AF23 },
1627 { "af31", IPTOS_DSCP_AF31 },
1628 { "af32", IPTOS_DSCP_AF32 },
1629 { "af33", IPTOS_DSCP_AF33 },
1630 { "af41", IPTOS_DSCP_AF41 },
1631 { "af42", IPTOS_DSCP_AF42 },
1632 { "af43", IPTOS_DSCP_AF43 },
1633 { "critical", IPTOS_PREC_CRITIC_ECP },
1634 { "cs0", IPTOS_DSCP_CS0 },
1635 { "cs1", IPTOS_DSCP_CS1 },
1636 { "cs2", IPTOS_DSCP_CS2 },
1637 { "cs3", IPTOS_DSCP_CS3 },
1638 { "cs4", IPTOS_DSCP_CS4 },
1639 { "cs5", IPTOS_DSCP_CS5 },
1640 { "cs6", IPTOS_DSCP_CS6 },
1641 { "cs7", IPTOS_DSCP_CS7 },
1642 { "ef", IPTOS_DSCP_EF },
1643 { "inetcontrol", IPTOS_PREC_INTERNETCONTROL },
1644 { "lowdelay", IPTOS_LOWDELAY },
1645 { "netcontrol", IPTOS_PREC_NETCONTROL },
1646 { "reliability", IPTOS_RELIABILITY },
1647 { "throughput", IPTOS_THROUGHPUT },
1648 { NULL, -1 },
1649 };
1650
1651 for (t = toskeywords; t->keyword != NULL; t++) {
1652 if (strcmp(s, t->keyword) == 0) {
1653 *val = t->val;
1654 return 1;
1655 }
1656 }
1657
1658 return 0;
1659 }
1660
1661 int
process_tls_opt(char * s,int * flags)1662 process_tls_opt(char *s, int *flags)
1663 {
1664 size_t len;
1665 char *v;
1666
1667 const struct tlskeywords {
1668 const char *keyword;
1669 int flag;
1670 char **value;
1671 } *t, tlskeywords[] = {
1672 { "ciphers", -1, &tls_ciphers },
1673 { "clientcert", TLS_CCERT, NULL },
1674 { "muststaple", TLS_MUSTSTAPLE, NULL },
1675 { "noverify", TLS_NOVERIFY, NULL },
1676 { "noname", TLS_NONAME, NULL },
1677 { "protocols", -1, &tls_protocols },
1678 { NULL, -1, NULL },
1679 };
1680
1681 len = strlen(s);
1682 if ((v = strchr(s, '=')) != NULL) {
1683 len = v - s;
1684 v++;
1685 }
1686
1687 for (t = tlskeywords; t->keyword != NULL; t++) {
1688 if (strlen(t->keyword) == len &&
1689 strncmp(s, t->keyword, len) == 0) {
1690 if (t->value != NULL) {
1691 if (v == NULL)
1692 errx(1, "invalid tls value `%s'", s);
1693 *t->value = v;
1694 } else {
1695 *flags |= t->flag;
1696 }
1697 return 1;
1698 }
1699 }
1700 return 0;
1701 }
1702
1703 void
save_peer_cert(struct tls * tls_ctx,FILE * fp)1704 save_peer_cert(struct tls *tls_ctx, FILE *fp)
1705 {
1706 const char *pem;
1707 size_t plen;
1708
1709 if ((pem = tls_peer_cert_chain_pem(tls_ctx, &plen)) == NULL)
1710 errx(1, "Can't get peer certificate");
1711 if (fprintf(fp, "%.*s", (int)plen, pem) < 0)
1712 err(1, "unable to save peer cert");
1713 if (fflush(fp) != 0)
1714 err(1, "unable to flush peer cert");
1715 }
1716
1717 void
report_tls(struct tls * tls_ctx,char * host)1718 report_tls(struct tls *tls_ctx, char *host)
1719 {
1720 time_t t;
1721 const char *ocsp_url;
1722
1723 fprintf(stderr, "TLS handshake negotiated %s/%s with host %s\n",
1724 tls_conn_version(tls_ctx), tls_conn_cipher(tls_ctx), host);
1725 fprintf(stderr, "Peer name: %s\n",
1726 tls_expectname ? tls_expectname : host);
1727 if (tls_peer_cert_subject(tls_ctx))
1728 fprintf(stderr, "Subject: %s\n",
1729 tls_peer_cert_subject(tls_ctx));
1730 if (tls_peer_cert_issuer(tls_ctx))
1731 fprintf(stderr, "Issuer: %s\n",
1732 tls_peer_cert_issuer(tls_ctx));
1733 if ((t = tls_peer_cert_notbefore(tls_ctx)) != -1)
1734 fprintf(stderr, "Valid From: %s", ctime(&t));
1735 if ((t = tls_peer_cert_notafter(tls_ctx)) != -1)
1736 fprintf(stderr, "Valid Until: %s", ctime(&t));
1737 if (tls_peer_cert_hash(tls_ctx))
1738 fprintf(stderr, "Cert Hash: %s\n",
1739 tls_peer_cert_hash(tls_ctx));
1740 ocsp_url = tls_peer_ocsp_url(tls_ctx);
1741 if (ocsp_url != NULL)
1742 fprintf(stderr, "OCSP URL: %s\n", ocsp_url);
1743 switch (tls_peer_ocsp_response_status(tls_ctx)) {
1744 case TLS_OCSP_RESPONSE_SUCCESSFUL:
1745 fprintf(stderr, "OCSP Stapling: %s\n",
1746 tls_peer_ocsp_result(tls_ctx) == NULL ? "" :
1747 tls_peer_ocsp_result(tls_ctx));
1748 fprintf(stderr,
1749 " response_status=%d cert_status=%d crl_reason=%d\n",
1750 tls_peer_ocsp_response_status(tls_ctx),
1751 tls_peer_ocsp_cert_status(tls_ctx),
1752 tls_peer_ocsp_crl_reason(tls_ctx));
1753 t = tls_peer_ocsp_this_update(tls_ctx);
1754 fprintf(stderr, " this update: %s",
1755 t != -1 ? ctime(&t) : "\n");
1756 t = tls_peer_ocsp_next_update(tls_ctx);
1757 fprintf(stderr, " next update: %s",
1758 t != -1 ? ctime(&t) : "\n");
1759 t = tls_peer_ocsp_revocation_time(tls_ctx);
1760 fprintf(stderr, " revocation: %s",
1761 t != -1 ? ctime(&t) : "\n");
1762 break;
1763 case -1:
1764 break;
1765 default:
1766 fprintf(stderr,
1767 "OCSP Stapling: failure - response_status %d (%s)\n",
1768 tls_peer_ocsp_response_status(tls_ctx),
1769 tls_peer_ocsp_result(tls_ctx) == NULL ? "" :
1770 tls_peer_ocsp_result(tls_ctx));
1771 break;
1772 }
1773 }
1774
1775 void
report_sock(const char * msg,const struct sockaddr * sa,socklen_t salen,char * path)1776 report_sock(const char *msg, const struct sockaddr *sa, socklen_t salen,
1777 char *path)
1778 {
1779 char host[NI_MAXHOST], port[NI_MAXSERV];
1780 int herr;
1781 int flags = NI_NUMERICSERV;
1782
1783 if (path != NULL) {
1784 fprintf(stderr, "%s on %s\n", msg, path);
1785 return;
1786 }
1787
1788 if (nflag)
1789 flags |= NI_NUMERICHOST;
1790
1791 herr = getnameinfo(sa, salen, host, sizeof(host), port, sizeof(port),
1792 flags);
1793 switch (herr) {
1794 case 0:
1795 break;
1796 case EAI_SYSTEM:
1797 err(1, "getnameinfo");
1798 default:
1799 errx(1, "getnameinfo: %s", gai_strerror(herr));
1800 }
1801
1802 fprintf(stderr, "%s on %s %s\n", msg, host, port);
1803 }
1804
1805 void
help(void)1806 help(void)
1807 {
1808 usage(0);
1809 fprintf(stderr, "\tCommand Summary:\n\
1810 \t-4 Use IPv4\n\
1811 \t-6 Use IPv6\n\
1812 \t-C certfile Public key file\n\
1813 \t-c Use TLS\n\
1814 \t-D Enable the debug socket option\n\
1815 \t-d Detach from stdin\n\
1816 \t-e name\t Required name in peer certificate\n\
1817 \t-F Pass socket fd\n\
1818 \t-H hash\t Hash string of peer certificate\n\
1819 \t-h This help text\n\
1820 \t-I length TCP receive buffer length\n\
1821 \t-i interval Delay interval for lines sent, ports scanned\n\
1822 \t-K keyfile Private key file\n\
1823 \t-k Keep inbound sockets open for multiple connects\n\
1824 \t-l Listen mode, for inbound connects\n\
1825 \t-M ttl Outgoing TTL / Hop Limit\n\
1826 \t-m minttl Minimum incoming TTL / Hop Limit\n\
1827 \t-N Shutdown the network socket after EOF on stdin\n\
1828 \t-n Suppress name/port resolutions\n\
1829 \t-O length TCP send buffer length\n\
1830 \t-o staplefile Staple file\n\
1831 \t-P proxyuser\tUsername for proxy authentication\n\
1832 \t-p port\t Specify local port for remote connects\n\
1833 \t-R CAfile CA bundle\n\
1834 \t-r Randomize remote ports\n\
1835 \t-S Enable the TCP MD5 signature option\n\
1836 \t-s sourceaddr Local source address\n\
1837 \t-T keyword TOS value or TLS options\n\
1838 \t-t Answer TELNET negotiation\n\
1839 \t-U Use UNIX domain socket\n\
1840 \t-u UDP mode\n\
1841 \t-V rtable Specify alternate routing table\n\
1842 \t-v Verbose\n\
1843 \t-W recvlimit Terminate after receiving a number of packets\n\
1844 \t-w timeout Timeout for connects and final net reads\n\
1845 \t-X proto Proxy protocol: \"4\", \"5\" (SOCKS) or \"connect\"\n\
1846 \t-x addr[:port]\tSpecify proxy address and port\n\
1847 \t-Z Peer certificate file\n\
1848 \t-z Zero-I/O mode [used for scanning]\n\
1849 Port numbers can be individual or ranges: lo-hi [inclusive]\n");
1850 exit(1);
1851 }
1852
1853 void
usage(int ret)1854 usage(int ret)
1855 {
1856 fprintf(stderr,
1857 "usage: nc [-46cDdFhklNnrStUuvz] [-C certfile] [-e name] "
1858 "[-H hash] [-I length]\n"
1859 "\t [-i interval] [-K keyfile] [-M ttl] [-m minttl] [-O length]\n"
1860 "\t [-o staplefile] [-P proxy_username] [-p source_port] "
1861 "[-R CAfile]\n"
1862 "\t [-s sourceaddr] [-T keyword] [-V rtable] [-W recvlimit] "
1863 "[-w timeout]\n"
1864 "\t [-X proxy_protocol] [-x proxy_address[:port]] "
1865 "[-Z peercertfile]\n"
1866 "\t [destination] [port]\n");
1867 if (ret)
1868 exit(1);
1869 }
1870