1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 1983, 1991, 1993, 1994
5 * The Regents of the University of California. All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
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 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29 #include <sys/cdefs.h>
30 #include <sys/filio.h>
31 #include <sys/ioccom.h>
32 #include <sys/param.h>
33 #include <sys/stat.h>
34 #include <sys/socket.h>
35 #include <sys/sysctl.h>
36 #include <sys/ucred.h>
37 #include <sys/uio.h>
38 #include <sys/utsname.h>
39
40 #include <ctype.h>
41 #include <err.h>
42 #include <errno.h>
43 #include <fcntl.h>
44 #include <limits.h>
45 #include <pwd.h>
46 #include <signal.h>
47 #include <stdlib.h>
48 #include <string.h>
49 #include <sysexits.h>
50 #include <syslog.h>
51 #include <unistd.h>
52
53 #include "inetd.h"
54
55 static void chargen_dg(int, struct servtab *);
56 static void chargen_stream(int, struct servtab *);
57 static void daytime_dg(int, struct servtab *);
58 static void daytime_stream(int, struct servtab *);
59 static void discard_dg(int, struct servtab *);
60 static void discard_stream(int, struct servtab *);
61 static void echo_dg(int, struct servtab *);
62 static void echo_stream(int, struct servtab *);
63 static int get_line(int, char *, int);
64 static void iderror(int, int, int, const char *);
65 static void ident_stream(int, struct servtab *);
66 static void initring(void);
67 static uint32_t machtime(void);
68 static void machtime_dg(int, struct servtab *);
69 static void machtime_stream(int, struct servtab *);
70
71 static char ring[128];
72 static char *endring;
73
74 struct biltin biltins[] = {
75 /* Echo received data */
76 { "echo", SOCK_STREAM, 1, -1, echo_stream },
77 { "echo", SOCK_DGRAM, 0, 1, echo_dg },
78
79 /* Internet /dev/null */
80 { "discard", SOCK_STREAM, 1, -1, discard_stream },
81 { "discard", SOCK_DGRAM, 0, 1, discard_dg },
82
83 /* Return 32 bit time since 1900 */
84 { "time", SOCK_STREAM, 0, -1, machtime_stream },
85 { "time", SOCK_DGRAM, 0, 1, machtime_dg },
86
87 /* Return human-readable time */
88 { "daytime", SOCK_STREAM, 0, -1, daytime_stream },
89 { "daytime", SOCK_DGRAM, 0, 1, daytime_dg },
90
91 /* Familiar character generator */
92 { "chargen", SOCK_STREAM, 1, -1, chargen_stream },
93 { "chargen", SOCK_DGRAM, 0, 1, chargen_dg },
94
95 { "tcpmux", SOCK_STREAM, 1, -1, (bi_fn_t *)tcpmux },
96
97 { "auth", SOCK_STREAM, 1, -1, ident_stream },
98
99 { NULL, 0, 0, 0, NULL }
100 };
101
102 /*
103 * RFC864 Character Generator Protocol. Generates character data without
104 * any regard for input.
105 */
106
107 static void
initring(void)108 initring(void)
109 {
110 int i;
111
112 endring = ring;
113
114 for (i = 0; i <= 128; ++i)
115 if (isprint(i))
116 *endring++ = i;
117 }
118
119 /* Character generator
120 * The RFC says that we should send back a random number of
121 * characters chosen from the range 0 to 512. We send LINESIZ+2.
122 */
123 /* ARGSUSED */
124 static void
chargen_dg(int s,struct servtab * sep)125 chargen_dg(int s, struct servtab *sep)
126 {
127 struct sockaddr_storage ss;
128 static char *rs;
129 int len;
130 socklen_t size;
131 char text[LINESIZ+2];
132
133 if (endring == NULL)
134 initring();
135 if (rs == NULL)
136 rs = ring;
137
138 size = sizeof(ss);
139 if (recvfrom(s, text, sizeof(text), 0,
140 (struct sockaddr *)&ss, &size) < 0)
141 return;
142
143 if (check_loop((struct sockaddr *)&ss, sep))
144 return;
145
146 if ((len = endring - rs) >= LINESIZ)
147 memmove(text, rs, LINESIZ);
148 else {
149 memmove(text, rs, len);
150 memmove(text + len, ring, LINESIZ - len);
151 }
152 if (++rs == endring)
153 rs = ring;
154 text[LINESIZ] = '\r';
155 text[LINESIZ + 1] = '\n';
156 (void) sendto(s, text, sizeof(text), 0, (struct sockaddr *)&ss, size);
157 }
158
159 /* Character generator */
160 /* ARGSUSED */
161 static void
chargen_stream(int s,struct servtab * sep)162 chargen_stream(int s, struct servtab *sep)
163 {
164 int len;
165 char *rs, text[LINESIZ+2];
166
167 inetd_setproctitle(sep->se_service, s);
168
169 if (!endring)
170 initring();
171
172 text[LINESIZ] = '\r';
173 text[LINESIZ + 1] = '\n';
174 for (rs = ring;;) {
175 if ((len = endring - rs) >= LINESIZ)
176 memmove(text, rs, LINESIZ);
177 else {
178 memmove(text, rs, len);
179 memmove(text + len, ring, LINESIZ - len);
180 }
181 if (++rs == endring)
182 rs = ring;
183 if (write(s, text, sizeof(text)) != sizeof(text))
184 break;
185 }
186 exit(0);
187 }
188
189 /*
190 * RFC867 Daytime Protocol. Sends the current date and time as an ascii
191 * character string without any regard for input.
192 */
193
194 /* Return human-readable time of day */
195 /* ARGSUSED */
196 static void
daytime_dg(int s,struct servtab * sep)197 daytime_dg(int s, struct servtab *sep)
198 {
199 char buffer[256];
200 time_t now;
201 struct sockaddr_storage ss;
202 socklen_t size;
203
204 now = time((time_t *) 0);
205
206 size = sizeof(ss);
207 if (recvfrom(s, buffer, sizeof(buffer), 0,
208 (struct sockaddr *)&ss, &size) < 0)
209 return;
210
211 if (check_loop((struct sockaddr *)&ss, sep))
212 return;
213
214 (void) sprintf(buffer, "%.24s\r\n", ctime(&now));
215 (void) sendto(s, buffer, strlen(buffer), 0,
216 (struct sockaddr *)&ss, size);
217 }
218
219 /* Return human-readable time of day */
220 /* ARGSUSED */
221 static void
daytime_stream(int s,struct servtab * sep __unused)222 daytime_stream(int s, struct servtab *sep __unused)
223 {
224 char buffer[256];
225 time_t now;
226
227 now = time((time_t *) 0);
228
229 (void) sprintf(buffer, "%.24s\r\n", ctime(&now));
230 (void) send(s, buffer, strlen(buffer), MSG_EOF);
231 }
232
233 /*
234 * RFC863 Discard Protocol. Any data received is thrown away and no response
235 * is sent.
236 */
237
238 /* Discard service -- ignore data */
239 /* ARGSUSED */
240 static void
discard_dg(int s,struct servtab * sep __unused)241 discard_dg(int s, struct servtab *sep __unused)
242 {
243 char buffer[BUFSIZE];
244
245 (void) read(s, buffer, sizeof(buffer));
246 }
247
248 /* Discard service -- ignore data */
249 /* ARGSUSED */
250 static void
discard_stream(int s,struct servtab * sep)251 discard_stream(int s, struct servtab *sep)
252 {
253 int ret;
254 char buffer[BUFSIZE];
255
256 inetd_setproctitle(sep->se_service, s);
257 while (1) {
258 while ((ret = read(s, buffer, sizeof(buffer))) > 0)
259 ;
260 if (ret == 0 || errno != EINTR)
261 break;
262 }
263 exit(0);
264 }
265
266 /*
267 * RFC862 Echo Protocol. Any data received is sent back to the sender as
268 * received.
269 */
270
271 /* Echo service -- echo data back */
272 /* ARGSUSED */
273 static void
echo_dg(int s,struct servtab * sep)274 echo_dg(int s, struct servtab *sep)
275 {
276 char buffer[65536]; /* Should be sizeof(max datagram). */
277 int i;
278 socklen_t size;
279 struct sockaddr_storage ss;
280
281 size = sizeof(ss);
282 if ((i = recvfrom(s, buffer, sizeof(buffer), 0,
283 (struct sockaddr *)&ss, &size)) < 0)
284 return;
285
286 if (check_loop((struct sockaddr *)&ss, sep))
287 return;
288
289 (void) sendto(s, buffer, i, 0, (struct sockaddr *)&ss, size);
290 }
291
292 /* Echo service -- echo data back */
293 /* ARGSUSED */
294 static void
echo_stream(int s,struct servtab * sep)295 echo_stream(int s, struct servtab *sep)
296 {
297 char buffer[BUFSIZE];
298 int i;
299
300 inetd_setproctitle(sep->se_service, s);
301 while ((i = read(s, buffer, sizeof(buffer))) > 0 &&
302 write(s, buffer, i) > 0)
303 ;
304 exit(0);
305 }
306
307 /*
308 * RFC1413 Identification Protocol. Given a TCP port number pair, return a
309 * character string which identifies the owner of that connection on the
310 * server's system. Extended to allow for ~/.fakeid support and ~/.noident
311 * support.
312 */
313
314 /* RFC 1413 says the following are the only errors you can return. */
315 #define ID_INVALID "INVALID-PORT" /* Port number improperly specified. */
316 #define ID_NOUSER "NO-USER" /* Port not in use/not identifiable. */
317 #define ID_HIDDEN "HIDDEN-USER" /* Hidden at user's request. */
318 #define ID_UNKNOWN "UNKNOWN-ERROR" /* Everything else. */
319
320 /* Generic ident_stream error-sending func */
321 /* ARGSUSED */
322 static void
iderror(int lport,int fport,int s,const char * er)323 iderror(int lport, int fport, int s, const char *er)
324 {
325 char *p;
326
327 asprintf(&p, "%d , %d : ERROR : %s\r\n", lport, fport, er);
328 if (p == NULL) {
329 syslog(LOG_ERR, "asprintf: %m");
330 exit(EX_OSERR);
331 }
332 send(s, p, strlen(p), MSG_EOF);
333 free(p);
334
335 exit(0);
336 }
337
338 /* Ident service (AKA "auth") */
339 /* ARGSUSED */
340 static void
ident_stream(int s,struct servtab * sep)341 ident_stream(int s, struct servtab *sep)
342 {
343 struct utsname un;
344 struct stat sb;
345 struct sockaddr_in sin4[2];
346 #ifdef INET6
347 struct sockaddr_in6 sin6[2];
348 #endif
349 struct sockaddr_storage ss[2];
350 struct xucred uc;
351 struct timeval tv = {
352 10,
353 0
354 }, to;
355 struct passwd *pw = NULL;
356 fd_set fdset;
357 char buf[BUFSIZE], *p, **av, *osname = NULL, e;
358 char idbuf[MAXLOGNAME] = ""; /* Big enough to hold uid in decimal. */
359 socklen_t socklen;
360 ssize_t ssize;
361 size_t size, bufsiz;
362 int c, fflag = 0, nflag = 0, rflag = 0, argc = 0;
363 int gflag = 0, iflag = 0, Fflag = 0, getcredfail = 0, onreadlen;
364 u_short lport, fport;
365
366 inetd_setproctitle(sep->se_service, s);
367 /*
368 * Reset getopt() since we are a fork() but not an exec() from
369 * a parent which used getopt() already.
370 */
371 optind = 1;
372 optreset = 1;
373 /*
374 * Take the internal argument vector and count it out to make an
375 * argument count for getopt. This can be used for any internal
376 * service to read arguments and use getopt() easily.
377 */
378 for (av = sep->se_argv; *av; av++)
379 argc++;
380 if (argc) {
381 int sec, usec;
382 size_t i;
383 u_int32_t rnd32;
384
385 while ((c = getopt(argc, sep->se_argv, "d:fFgino:rt:")) != -1)
386 switch (c) {
387 case 'd':
388 if (!gflag)
389 strlcpy(idbuf, optarg, sizeof(idbuf));
390 break;
391 case 'f':
392 fflag = 1;
393 break;
394 case 'F':
395 fflag = 1;
396 Fflag=1;
397 break;
398 case 'g':
399 gflag = 1;
400 rnd32 = 0; /* Shush, compiler. */
401 /*
402 * The number of bits in "rnd32" divided
403 * by the number of bits needed per iteration
404 * gives a more optimal way to reload the
405 * random number only when necessary.
406 *
407 * 32 bits from arc4random corresponds to
408 * about 6 base-36 digits, so we reseed every 6.
409 */
410 for (i = 0; i < sizeof(idbuf) - 1; i++) {
411 static const char *const base36 =
412 "0123456789"
413 "abcdefghijklmnopqrstuvwxyz";
414 if (i % 6 == 0)
415 rnd32 = arc4random();
416 idbuf[i] = base36[rnd32 % 36];
417 rnd32 /= 36;
418 }
419 idbuf[i] = '\0';
420 break;
421 case 'i':
422 iflag = 1;
423 break;
424 case 'n':
425 nflag = 1;
426 break;
427 case 'o':
428 osname = optarg;
429 break;
430 case 'r':
431 rflag = 1;
432 break;
433 case 't':
434 switch (sscanf(optarg, "%d.%d", &sec, &usec)) {
435 case 2:
436 tv.tv_usec = usec;
437 /* FALLTHROUGH */
438 case 1:
439 tv.tv_sec = sec;
440 break;
441 default:
442 if (debug)
443 warnx("bad -t argument");
444 break;
445 }
446 break;
447 default:
448 break;
449 }
450 }
451 if (osname == NULL) {
452 if (uname(&un) == -1)
453 iderror(0, 0, s, ID_UNKNOWN);
454 osname = un.sysname;
455 }
456
457 /*
458 * We're going to prepare for and execute reception of a
459 * packet of data from the user. The data is in the format
460 * "local_port , foreign_port\r\n" (with local being the
461 * server's port and foreign being the client's.)
462 */
463 gettimeofday(&to, NULL);
464 to.tv_sec += tv.tv_sec;
465 to.tv_usec += tv.tv_usec;
466 if (to.tv_usec >= 1000000) {
467 to.tv_usec -= 1000000;
468 to.tv_sec++;
469 }
470
471 size = 0;
472 bufsiz = sizeof(buf) - 1;
473 FD_ZERO(&fdset);
474 while (bufsiz > 0) {
475 gettimeofday(&tv, NULL);
476 tv.tv_sec = to.tv_sec - tv.tv_sec;
477 tv.tv_usec = to.tv_usec - tv.tv_usec;
478 if (tv.tv_usec < 0) {
479 tv.tv_usec += 1000000;
480 tv.tv_sec--;
481 }
482 if (tv.tv_sec < 0)
483 break;
484 FD_SET(s, &fdset);
485 if (select(s + 1, &fdset, NULL, NULL, &tv) == -1)
486 iderror(0, 0, s, ID_UNKNOWN);
487 if (ioctl(s, FIONREAD, &onreadlen) == -1)
488 iderror(0, 0, s, ID_UNKNOWN);
489 if ((size_t)onreadlen > bufsiz)
490 onreadlen = bufsiz;
491 ssize = read(s, &buf[size], (size_t)onreadlen);
492 if (ssize == -1)
493 iderror(0, 0, s, ID_UNKNOWN);
494 else if (ssize == 0)
495 break;
496 bufsiz -= ssize;
497 size += ssize;
498 if (memchr(&buf[size - ssize], '\n', ssize) != NULL)
499 break;
500 }
501 buf[size] = '\0';
502 /* Read two characters, and check for a delimiting character */
503 if (sscanf(buf, "%hu , %hu%c", &lport, &fport, &e) != 3 || isdigit(e))
504 iderror(0, 0, s, ID_INVALID);
505
506 /* Send garbage? */
507 if (gflag)
508 goto printit;
509
510 /*
511 * If not "real" (-r), send a HIDDEN-USER error for everything.
512 * If -d is used to set a fallback username, this is used to
513 * override it, and the fallback is returned instead.
514 */
515 if (!rflag) {
516 if (*idbuf == '\0')
517 iderror(lport, fport, s, ID_HIDDEN);
518 goto printit;
519 }
520
521 /*
522 * We take the input and construct an array of two sockaddr_ins
523 * which contain the local address information and foreign
524 * address information, respectively, used to look up the
525 * credentials for the socket (which are returned by the
526 * sysctl "net.inet.tcp.getcred" when we call it.)
527 */
528 socklen = sizeof(ss[0]);
529 if (getsockname(s, (struct sockaddr *)&ss[0], &socklen) == -1)
530 iderror(lport, fport, s, ID_UNKNOWN);
531 socklen = sizeof(ss[1]);
532 if (getpeername(s, (struct sockaddr *)&ss[1], &socklen) == -1)
533 iderror(lport, fport, s, ID_UNKNOWN);
534 if (ss[0].ss_family != ss[1].ss_family)
535 iderror(lport, fport, s, ID_UNKNOWN);
536 size = sizeof(uc);
537 switch (ss[0].ss_family) {
538 case AF_INET:
539 sin4[0] = *(struct sockaddr_in *)&ss[0];
540 sin4[0].sin_port = htons(lport);
541 sin4[1] = *(struct sockaddr_in *)&ss[1];
542 sin4[1].sin_port = htons(fport);
543 if (sysctlbyname("net.inet.tcp.getcred", &uc, &size, sin4,
544 sizeof(sin4)) == -1)
545 getcredfail = errno;
546 break;
547 #ifdef INET6
548 case AF_INET6:
549 sin6[0] = *(struct sockaddr_in6 *)&ss[0];
550 sin6[0].sin6_port = htons(lport);
551 sin6[1] = *(struct sockaddr_in6 *)&ss[1];
552 sin6[1].sin6_port = htons(fport);
553 if (sysctlbyname("net.inet6.tcp6.getcred", &uc, &size, sin6,
554 sizeof(sin6)) == -1)
555 getcredfail = errno;
556 break;
557 #endif
558 default: /* should not reach here */
559 getcredfail = EAFNOSUPPORT;
560 break;
561 }
562 if (getcredfail != 0 || uc.cr_version != XUCRED_VERSION) {
563 if (*idbuf == '\0')
564 iderror(lport, fport, s,
565 getcredfail == ENOENT ? ID_NOUSER : ID_UNKNOWN);
566 goto printit;
567 }
568
569 /* Look up the pw to get the username and home directory*/
570 errno = 0;
571 pw = getpwuid(uc.cr_uid);
572 if (pw == NULL)
573 iderror(lport, fport, s, errno == 0 ? ID_NOUSER : ID_UNKNOWN);
574
575 if (iflag)
576 snprintf(idbuf, sizeof(idbuf), "%u", (unsigned)pw->pw_uid);
577 else
578 strlcpy(idbuf, pw->pw_name, sizeof(idbuf));
579
580 /*
581 * If enabled, we check for a file named ".noident" in the user's
582 * home directory. If found, we return HIDDEN-USER.
583 */
584 if (nflag) {
585 if (asprintf(&p, "%s/.noident", pw->pw_dir) == -1)
586 iderror(lport, fport, s, ID_UNKNOWN);
587 if (lstat(p, &sb) == 0) {
588 free(p);
589 iderror(lport, fport, s, ID_HIDDEN);
590 }
591 free(p);
592 }
593
594 /*
595 * Here, if enabled, we read a user's ".fakeid" file in their
596 * home directory. It consists of a line containing the name
597 * they want.
598 */
599 if (fflag) {
600 int fakeid_fd;
601
602 /*
603 * Here we set ourself to effectively be the user, so we don't
604 * open any files we have no permission to open, especially
605 * symbolic links to sensitive root-owned files or devices.
606 */
607 if (initgroups(pw->pw_name, pw->pw_gid) == -1)
608 iderror(lport, fport, s, ID_UNKNOWN);
609 if (seteuid(pw->pw_uid) == -1)
610 iderror(lport, fport, s, ID_UNKNOWN);
611 /*
612 * We can't stat() here since that would be a race
613 * condition.
614 * Therefore, we open the file we have permissions to open
615 * and if it's not a regular file, we close it and end up
616 * returning the user's real username.
617 */
618 if (asprintf(&p, "%s/.fakeid", pw->pw_dir) == -1)
619 iderror(lport, fport, s, ID_UNKNOWN);
620 fakeid_fd = open(p, O_RDONLY | O_NONBLOCK);
621 free(p);
622 if (fakeid_fd == -1 || fstat(fakeid_fd, &sb) == -1 ||
623 !S_ISREG(sb.st_mode))
624 goto fakeid_fail;
625
626 if ((ssize = read(fakeid_fd, buf, sizeof(buf) - 1)) < 0)
627 goto fakeid_fail;
628 buf[ssize] = '\0';
629
630 /*
631 * Usually, the file will have the desired identity
632 * in the form "identity\n". Allow for leading white
633 * space and trailing white space/end of line.
634 */
635 p = buf;
636 p += strspn(p, " \t");
637 p[strcspn(p, " \t\r\n")] = '\0';
638 if (strlen(p) > MAXLOGNAME - 1) /* Too long (including nul)? */
639 p[MAXLOGNAME - 1] = '\0';
640
641 /*
642 * If the name is a zero-length string or matches it
643 * the id or name of another user (unless permitted by -F)
644 * then it is invalid.
645 */
646 if (*p == '\0')
647 goto fakeid_fail;
648 if (!Fflag) {
649 if (iflag) {
650 const char *errstr;
651 uid_t uid;
652
653 uid = strtonum(p, 0, UID_MAX, &errstr);
654 if (errstr != NULL)
655 goto fakeid_fail;
656
657 if (getpwuid(uid) != NULL)
658 goto fakeid_fail;
659 } else {
660 if (getpwnam(p) != NULL)
661 goto fakeid_fail;
662 }
663 }
664
665 strlcpy(idbuf, p, sizeof(idbuf));
666
667 fakeid_fail:
668 if (fakeid_fd != -1)
669 close(fakeid_fd);
670 }
671
672 printit:
673 /* Finally, we make and send the reply. */
674 if (asprintf(&p, "%d , %d : USERID : %s : %s\r\n", lport, fport, osname,
675 idbuf) == -1) {
676 syslog(LOG_ERR, "asprintf: %m");
677 exit(EX_OSERR);
678 }
679 send(s, p, strlen(p), MSG_EOF);
680 free(p);
681
682 exit(0);
683 }
684
685 /*
686 * RFC738/868 Time Server.
687 * Return a machine readable date and time, in the form of the
688 * number of seconds since midnight, Jan 1, 1900. Since gettimeofday
689 * returns the number of seconds since midnight, Jan 1, 1970,
690 * we must add 2208988800 seconds to this figure to make up for
691 * some seventy years Bell Labs was asleep.
692 */
693
694 static uint32_t
machtime(void)695 machtime(void)
696 {
697
698 #define OFFSET ((uint32_t)25567 * 24*60*60)
699 return (htonl((uint32_t)(time(NULL) + OFFSET)));
700 #undef OFFSET
701 }
702
703 /* ARGSUSED */
704 static void
machtime_dg(int s,struct servtab * sep)705 machtime_dg(int s, struct servtab *sep)
706 {
707 uint32_t result;
708 struct sockaddr_storage ss;
709 socklen_t size;
710
711 size = sizeof(ss);
712 if (recvfrom(s, (char *)&result, sizeof(result), 0,
713 (struct sockaddr *)&ss, &size) < 0)
714 return;
715
716 if (check_loop((struct sockaddr *)&ss, sep))
717 return;
718
719 result = machtime();
720 (void) sendto(s, (char *) &result, sizeof(result), 0,
721 (struct sockaddr *)&ss, size);
722 }
723
724 /* ARGSUSED */
725 static void
machtime_stream(int s,struct servtab * sep __unused)726 machtime_stream(int s, struct servtab *sep __unused)
727 {
728 uint32_t result;
729
730 result = machtime();
731 (void) send(s, (char *) &result, sizeof(result), MSG_EOF);
732 }
733
734 /*
735 * RFC1078 TCP Port Service Multiplexer (TCPMUX). Service connections to
736 * services based on the service name sent.
737 *
738 * Based on TCPMUX.C by Mark K. Lottor November 1988
739 * sri-nic::ps:<mkl>tcpmux.c
740 */
741
742 #define MAX_SERV_LEN (256+2) /* 2 bytes for \r\n */
743 #define strwrite(fd, buf) (void) write(fd, buf, sizeof(buf)-1)
744
745 static int /* # of characters up to \r,\n or \0 */
get_line(int fd,char * buf,int len)746 get_line(int fd, char *buf, int len)
747 {
748 int count = 0, n;
749 struct sigaction sa;
750
751 sa.sa_flags = 0;
752 sigemptyset(&sa.sa_mask);
753 sa.sa_handler = SIG_DFL;
754 sigaction(SIGALRM, &sa, (struct sigaction *)0);
755 do {
756 alarm(10);
757 n = read(fd, buf, len-count);
758 alarm(0);
759 if (n == 0)
760 return (count);
761 if (n < 0)
762 return (-1);
763 while (--n >= 0) {
764 if (*buf == '\r' || *buf == '\n' || *buf == '\0')
765 return (count);
766 count++;
767 buf++;
768 }
769 } while (count < len);
770 return (count);
771 }
772
773 struct servtab *
tcpmux(int s)774 tcpmux(int s)
775 {
776 struct servtab *sep;
777 char service[MAX_SERV_LEN+1];
778 int len;
779
780 /* Get requested service name */
781 if ((len = get_line(s, service, MAX_SERV_LEN)) < 0) {
782 strwrite(s, "-Error reading service name\r\n");
783 return (NULL);
784 }
785 service[len] = '\0';
786
787 if (debug)
788 warnx("tcpmux: someone wants %s", service);
789
790 /*
791 * Help is a required command, and lists available services,
792 * one per line.
793 */
794 if (!strcasecmp(service, "help")) {
795 for (sep = servtab; sep; sep = sep->se_next) {
796 if (!ISMUX(sep))
797 continue;
798 (void)write(s,sep->se_service,strlen(sep->se_service));
799 strwrite(s, "\r\n");
800 }
801 return (NULL);
802 }
803
804 /* Try matching a service in inetd.conf with the request */
805 for (sep = servtab; sep; sep = sep->se_next) {
806 if (!ISMUX(sep))
807 continue;
808 if (!strcasecmp(service, sep->se_service)) {
809 if (ISMUXPLUS(sep)) {
810 strwrite(s, "+Go\r\n");
811 }
812 return (sep);
813 }
814 }
815 strwrite(s, "-Service not available\r\n");
816 return (NULL);
817 }
818