2 * Copyright (c) 1983, 1991, 1993, 1994
3 * The Regents of the University of California. All rights reserved.
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD$");
30 #include <sys/filio.h>
31 #include <sys/ioccom.h>
32 #include <sys/param.h>
34 #include <sys/socket.h>
35 #include <sys/sysctl.h>
36 #include <sys/ucred.h>
38 #include <sys/utsname.h>
55 void chargen_dg(int, struct servtab *);
56 void chargen_stream(int, struct servtab *);
57 void daytime_dg(int, struct servtab *);
58 void daytime_stream(int, struct servtab *);
59 void discard_dg(int, struct servtab *);
60 void discard_stream(int, struct servtab *);
61 void echo_dg(int, struct servtab *);
62 void echo_stream(int, struct servtab *);
63 static int getline(int, char *, int);
64 void iderror(int, int, int, const char *);
65 void ident_stream(int, struct servtab *);
67 uint32_t machtime(void);
68 void machtime_dg(int, struct servtab *);
69 void machtime_stream(int, struct servtab *);
75 struct biltin biltins[] = {
76 /* Echo received data */
77 { "echo", SOCK_STREAM, 1, -1, echo_stream },
78 { "echo", SOCK_DGRAM, 0, 1, echo_dg },
80 /* Internet /dev/null */
81 { "discard", SOCK_STREAM, 1, -1, discard_stream },
82 { "discard", SOCK_DGRAM, 0, 1, discard_dg },
84 /* Return 32 bit time since 1900 */
85 { "time", SOCK_STREAM, 0, -1, machtime_stream },
86 { "time", SOCK_DGRAM, 0, 1, machtime_dg },
88 /* Return human-readable time */
89 { "daytime", SOCK_STREAM, 0, -1, daytime_stream },
90 { "daytime", SOCK_DGRAM, 0, 1, daytime_dg },
92 /* Familiar character generator */
93 { "chargen", SOCK_STREAM, 1, -1, chargen_stream },
94 { "chargen", SOCK_DGRAM, 0, 1, chargen_dg },
96 { "tcpmux", SOCK_STREAM, 1, -1, (bi_fn_t *)tcpmux },
98 { "auth", SOCK_STREAM, 1, -1, ident_stream },
100 { NULL, 0, 0, 0, NULL }
104 * RFC864 Character Generator Protocol. Generates character data without
105 * any regard for input.
115 for (i = 0; i <= 128; ++i)
120 /* Character generator
121 * The RFC says that we should send back a random number of
122 * characters chosen from the range 0 to 512. We send LINESIZ+2.
126 chargen_dg(int s, struct servtab *sep)
128 struct sockaddr_storage ss;
132 char text[LINESIZ+2];
140 if (recvfrom(s, text, sizeof(text), 0,
141 (struct sockaddr *)&ss, &size) < 0)
144 if (check_loop((struct sockaddr *)&ss, sep))
147 if ((len = endring - rs) >= LINESIZ)
148 memmove(text, rs, LINESIZ);
150 memmove(text, rs, len);
151 memmove(text + len, ring, LINESIZ - len);
155 text[LINESIZ] = '\r';
156 text[LINESIZ + 1] = '\n';
157 (void) sendto(s, text, sizeof(text), 0, (struct sockaddr *)&ss, size);
160 /* Character generator */
163 chargen_stream(int s, struct servtab *sep)
166 char *rs, text[LINESIZ+2];
168 inetd_setproctitle(sep->se_service, s);
175 text[LINESIZ] = '\r';
176 text[LINESIZ + 1] = '\n';
178 if ((len = endring - rs) >= LINESIZ)
179 memmove(text, rs, LINESIZ);
181 memmove(text, rs, len);
182 memmove(text + len, ring, LINESIZ - len);
186 if (write(s, text, sizeof(text)) != sizeof(text))
193 * RFC867 Daytime Protocol. Sends the current date and time as an ascii
194 * character string without any regard for input.
197 /* Return human-readable time of day */
200 daytime_dg(int s, struct servtab *sep)
204 struct sockaddr_storage ss;
207 now = time((time_t *) 0);
210 if (recvfrom(s, buffer, sizeof(buffer), 0,
211 (struct sockaddr *)&ss, &size) < 0)
214 if (check_loop((struct sockaddr *)&ss, sep))
217 (void) sprintf(buffer, "%.24s\r\n", ctime(&now));
218 (void) sendto(s, buffer, strlen(buffer), 0,
219 (struct sockaddr *)&ss, size);
222 /* Return human-readable time of day */
225 daytime_stream(int s, struct servtab *sep __unused)
230 now = time((time_t *) 0);
232 (void) sprintf(buffer, "%.24s\r\n", ctime(&now));
233 (void) send(s, buffer, strlen(buffer), MSG_EOF);
237 * RFC863 Discard Protocol. Any data received is thrown away and no response
241 /* Discard service -- ignore data */
244 discard_dg(int s, struct servtab *sep __unused)
246 char buffer[BUFSIZE];
248 (void) read(s, buffer, sizeof(buffer));
251 /* Discard service -- ignore data */
254 discard_stream(int s, struct servtab *sep)
257 char buffer[BUFSIZE];
259 inetd_setproctitle(sep->se_service, s);
261 while ((ret = read(s, buffer, sizeof(buffer))) > 0)
263 if (ret == 0 || errno != EINTR)
270 * RFC862 Echo Protocol. Any data received is sent back to the sender as
274 /* Echo service -- echo data back */
277 echo_dg(int s, struct servtab *sep)
279 char buffer[65536]; /* Should be sizeof(max datagram). */
282 struct sockaddr_storage ss;
285 if ((i = recvfrom(s, buffer, sizeof(buffer), 0,
286 (struct sockaddr *)&ss, &size)) < 0)
289 if (check_loop((struct sockaddr *)&ss, sep))
292 (void) sendto(s, buffer, i, 0, (struct sockaddr *)&ss, size);
295 /* Echo service -- echo data back */
298 echo_stream(int s, struct servtab *sep)
300 char buffer[BUFSIZE];
303 inetd_setproctitle(sep->se_service, s);
304 while ((i = read(s, buffer, sizeof(buffer))) > 0 &&
305 write(s, buffer, i) > 0)
311 * RFC1413 Identification Protocol. Given a TCP port number pair, return a
312 * character string which identifies the owner of that connection on the
313 * server's system. Extended to allow for ~/.fakeid support and ~/.noident
317 /* RFC 1413 says the following are the only errors you can return. */
318 #define ID_INVALID "INVALID-PORT" /* Port number improperly specified. */
319 #define ID_NOUSER "NO-USER" /* Port not in use/not identifable. */
320 #define ID_HIDDEN "HIDDEN-USER" /* Hiden at user's request. */
321 #define ID_UNKNOWN "UNKNOWN-ERROR" /* Everything else. */
323 /* Generic ident_stream error-sending func */
326 iderror(int lport, int fport, int s, const char *er)
330 asprintf(&p, "%d , %d : ERROR : %s\r\n", lport, fport, er);
332 syslog(LOG_ERR, "asprintf: %m");
335 send(s, p, strlen(p), MSG_EOF);
341 /* Ident service (AKA "auth") */
344 ident_stream(int s, struct servtab *sep)
348 struct sockaddr_in sin4[2];
350 struct sockaddr_in6 sin6[2];
352 struct sockaddr_storage ss[2];
354 struct timeval tv = {
358 struct passwd *pw = NULL;
360 char buf[BUFSIZE], *p, **av, *osname = NULL, e;
361 char idbuf[MAXLOGNAME] = ""; /* Big enough to hold uid in decimal. */
365 int c, fflag = 0, nflag = 0, rflag = 0, argc = 0;
366 int gflag = 0, iflag = 0, Fflag = 0, getcredfail = 0, onreadlen;
367 u_short lport, fport;
369 inetd_setproctitle(sep->se_service, s);
371 * Reset getopt() since we are a fork() but not an exec() from
372 * a parent which used getopt() already.
377 * Take the internal argument vector and count it out to make an
378 * argument count for getopt. This can be used for any internal
379 * service to read arguments and use getopt() easily.
381 for (av = sep->se_argv; *av; av++)
388 while ((c = getopt(argc, sep->se_argv, "d:fFgino:rt:")) != -1)
392 strlcpy(idbuf, optarg, sizeof(idbuf));
403 rnd32 = 0; /* Shush, compiler. */
405 * The number of bits in "rnd32" divided
406 * by the number of bits needed per iteration
407 * gives a more optimal way to reload the
408 * random number only when necessary.
410 * 32 bits from arc4random corresponds to
411 * about 6 base-36 digits, so we reseed evey 6.
413 for (i = 0; i < sizeof(idbuf) - 1; i++) {
414 static const char *const base36 =
416 "abcdefghijklmnopqrstuvwxyz";
418 rnd32 = arc4random();
419 idbuf[i] = base36[rnd32 % 36];
437 switch (sscanf(optarg, "%d.%d", &sec, &usec)) {
446 warnx("bad -t argument");
454 if (osname == NULL) {
455 if (uname(&un) == -1)
456 iderror(0, 0, s, ID_UNKNOWN);
461 * We're going to prepare for and execute reception of a
462 * packet of data from the user. The data is in the format
463 * "local_port , foreign_port\r\n" (with local being the
464 * server's port and foreign being the client's.)
466 gettimeofday(&to, NULL);
467 to.tv_sec += tv.tv_sec;
468 to.tv_usec += tv.tv_usec;
469 if (to.tv_usec >= 1000000) {
470 to.tv_usec -= 1000000;
475 bufsiz = sizeof(buf) - 1;
478 gettimeofday(&tv, NULL);
479 tv.tv_sec = to.tv_sec - tv.tv_sec;
480 tv.tv_usec = to.tv_usec - tv.tv_usec;
481 if (tv.tv_usec < 0) {
482 tv.tv_usec += 1000000;
488 if (select(s + 1, &fdset, NULL, NULL, &tv) == -1)
489 iderror(0, 0, s, ID_UNKNOWN);
490 if (ioctl(s, FIONREAD, &onreadlen) == -1)
491 iderror(0, 0, s, ID_UNKNOWN);
492 if ((size_t)onreadlen > bufsiz)
494 ssize = read(s, &buf[size], (size_t)onreadlen);
496 iderror(0, 0, s, ID_UNKNOWN);
501 if (memchr(&buf[size - ssize], '\n', ssize) != NULL)
505 /* Read two characters, and check for a delimiting character */
506 if (sscanf(buf, "%hu , %hu%c", &lport, &fport, &e) != 3 || isdigit(e))
507 iderror(0, 0, s, ID_INVALID);
514 * If not "real" (-r), send a HIDDEN-USER error for everything.
515 * If -d is used to set a fallback username, this is used to
516 * override it, and the fallback is returned instead.
520 iderror(lport, fport, s, ID_HIDDEN);
525 * We take the input and construct an array of two sockaddr_ins
526 * which contain the local address information and foreign
527 * address information, respectively, used to look up the
528 * credentials for the socket (which are returned by the
529 * sysctl "net.inet.tcp.getcred" when we call it.)
531 socklen = sizeof(ss[0]);
532 if (getsockname(s, (struct sockaddr *)&ss[0], &socklen) == -1)
533 iderror(lport, fport, s, ID_UNKNOWN);
534 socklen = sizeof(ss[1]);
535 if (getpeername(s, (struct sockaddr *)&ss[1], &socklen) == -1)
536 iderror(lport, fport, s, ID_UNKNOWN);
537 if (ss[0].ss_family != ss[1].ss_family)
538 iderror(lport, fport, s, ID_UNKNOWN);
540 switch (ss[0].ss_family) {
542 sin4[0] = *(struct sockaddr_in *)&ss[0];
543 sin4[0].sin_port = htons(lport);
544 sin4[1] = *(struct sockaddr_in *)&ss[1];
545 sin4[1].sin_port = htons(fport);
546 if (sysctlbyname("net.inet.tcp.getcred", &uc, &size, sin4,
552 sin6[0] = *(struct sockaddr_in6 *)&ss[0];
553 sin6[0].sin6_port = htons(lport);
554 sin6[1] = *(struct sockaddr_in6 *)&ss[1];
555 sin6[1].sin6_port = htons(fport);
556 if (sysctlbyname("net.inet6.tcp6.getcred", &uc, &size, sin6,
561 default: /* should not reach here */
562 getcredfail = EAFNOSUPPORT;
565 if (getcredfail != 0 || uc.cr_version != XUCRED_VERSION) {
567 iderror(lport, fport, s,
568 getcredfail == ENOENT ? ID_NOUSER : ID_UNKNOWN);
572 /* Look up the pw to get the username and home directory*/
574 pw = getpwuid(uc.cr_uid);
576 iderror(lport, fport, s, errno == 0 ? ID_NOUSER : ID_UNKNOWN);
579 snprintf(idbuf, sizeof(idbuf), "%u", (unsigned)pw->pw_uid);
581 strlcpy(idbuf, pw->pw_name, sizeof(idbuf));
584 * If enabled, we check for a file named ".noident" in the user's
585 * home directory. If found, we return HIDDEN-USER.
588 if (asprintf(&p, "%s/.noident", pw->pw_dir) == -1)
589 iderror(lport, fport, s, ID_UNKNOWN);
590 if (lstat(p, &sb) == 0) {
592 iderror(lport, fport, s, ID_HIDDEN);
598 * Here, if enabled, we read a user's ".fakeid" file in their
599 * home directory. It consists of a line containing the name
606 * Here we set ourself to effectively be the user, so we don't
607 * open any files we have no permission to open, especially
608 * symbolic links to sensitive root-owned files or devices.
610 if (initgroups(pw->pw_name, pw->pw_gid) == -1)
611 iderror(lport, fport, s, ID_UNKNOWN);
612 if (seteuid(pw->pw_uid) == -1)
613 iderror(lport, fport, s, ID_UNKNOWN);
615 * We can't stat() here since that would be a race
617 * Therefore, we open the file we have permissions to open
618 * and if it's not a regular file, we close it and end up
619 * returning the user's real username.
621 if (asprintf(&p, "%s/.fakeid", pw->pw_dir) == -1)
622 iderror(lport, fport, s, ID_UNKNOWN);
623 fakeid_fd = open(p, O_RDONLY | O_NONBLOCK);
625 if (fakeid_fd == -1 || fstat(fakeid_fd, &sb) == -1 ||
626 !S_ISREG(sb.st_mode))
629 if ((ssize = read(fakeid_fd, buf, sizeof(buf) - 1)) < 0)
634 * Usually, the file will have the desired identity
635 * in the form "identity\n". Allow for leading white
636 * space and trailing white space/end of line.
639 p += strspn(p, " \t");
640 p[strcspn(p, " \t\r\n")] = '\0';
641 if (strlen(p) > MAXLOGNAME - 1) /* Too long (including nul)? */
642 p[MAXLOGNAME - 1] = '\0';
645 * If the name is a zero-length string or matches it
646 * the id or name of another user (unless permitted by -F)
647 * then it is invalid.
653 if (p[strspn(p, "0123456789")] == '\0' &&
654 getpwuid(atoi(p)) != NULL)
657 if (getpwnam(p) != NULL)
662 strlcpy(idbuf, p, sizeof(idbuf));
670 /* Finally, we make and send the reply. */
671 if (asprintf(&p, "%d , %d : USERID : %s : %s\r\n", lport, fport, osname,
673 syslog(LOG_ERR, "asprintf: %m");
676 send(s, p, strlen(p), MSG_EOF);
683 * RFC738/868 Time Server.
684 * Return a machine readable date and time, in the form of the
685 * number of seconds since midnight, Jan 1, 1900. Since gettimeofday
686 * returns the number of seconds since midnight, Jan 1, 1970,
687 * we must add 2208988800 seconds to this figure to make up for
688 * some seventy years Bell Labs was asleep.
695 #define OFFSET ((uint32_t)25567 * 24*60*60)
696 return (htonl((uint32_t)(time(NULL) + OFFSET)));
702 machtime_dg(int s, struct servtab *sep)
705 struct sockaddr_storage ss;
709 if (recvfrom(s, (char *)&result, sizeof(result), 0,
710 (struct sockaddr *)&ss, &size) < 0)
713 if (check_loop((struct sockaddr *)&ss, sep))
717 (void) sendto(s, (char *) &result, sizeof(result), 0,
718 (struct sockaddr *)&ss, size);
723 machtime_stream(int s, struct servtab *sep __unused)
728 (void) send(s, (char *) &result, sizeof(result), MSG_EOF);
732 * RFC1078 TCP Port Service Multiplexer (TCPMUX). Service connections to
733 * services based on the service name sent.
735 * Based on TCPMUX.C by Mark K. Lottor November 1988
736 * sri-nic::ps:<mkl>tcpmux.c
739 #define MAX_SERV_LEN (256+2) /* 2 bytes for \r\n */
740 #define strwrite(fd, buf) (void) write(fd, buf, sizeof(buf)-1)
742 static int /* # of characters up to \r,\n or \0 */
743 getline(int fd, char *buf, int len)
749 sigemptyset(&sa.sa_mask);
750 sa.sa_handler = SIG_DFL;
751 sigaction(SIGALRM, &sa, (struct sigaction *)0);
754 n = read(fd, buf, len-count);
761 if (*buf == '\r' || *buf == '\n' || *buf == '\0')
766 } while (count < len);
774 char service[MAX_SERV_LEN+1];
777 /* Get requested service name */
778 if ((len = getline(s, service, MAX_SERV_LEN)) < 0) {
779 strwrite(s, "-Error reading service name\r\n");
785 warnx("tcpmux: someone wants %s", service);
788 * Help is a required command, and lists available services,
791 if (!strcasecmp(service, "help")) {
792 for (sep = servtab; sep; sep = sep->se_next) {
795 (void)write(s,sep->se_service,strlen(sep->se_service));
801 /* Try matching a service in inetd.conf with the request */
802 for (sep = servtab; sep; sep = sep->se_next) {
805 if (!strcasecmp(service, sep->se_service)) {
806 if (ISMUXPLUS(sep)) {
807 strwrite(s, "+Go\r\n");
812 strwrite(s, "-Service not available\r\n");