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);
173 text[LINESIZ] = '\r';
174 text[LINESIZ + 1] = '\n';
176 if ((len = endring - rs) >= LINESIZ)
177 memmove(text, rs, LINESIZ);
179 memmove(text, rs, len);
180 memmove(text + len, ring, LINESIZ - len);
184 if (write(s, text, sizeof(text)) != sizeof(text))
191 * RFC867 Daytime Protocol. Sends the current date and time as an ascii
192 * character string without any regard for input.
195 /* Return human-readable time of day */
198 daytime_dg(int s, struct servtab *sep)
202 struct sockaddr_storage ss;
205 now = time((time_t *) 0);
208 if (recvfrom(s, buffer, sizeof(buffer), 0,
209 (struct sockaddr *)&ss, &size) < 0)
212 if (check_loop((struct sockaddr *)&ss, sep))
215 (void) sprintf(buffer, "%.24s\r\n", ctime(&now));
216 (void) sendto(s, buffer, strlen(buffer), 0,
217 (struct sockaddr *)&ss, size);
220 /* Return human-readable time of day */
223 daytime_stream(int s, struct servtab *sep __unused)
228 now = time((time_t *) 0);
230 (void) sprintf(buffer, "%.24s\r\n", ctime(&now));
231 (void) send(s, buffer, strlen(buffer), MSG_EOF);
235 * RFC863 Discard Protocol. Any data received is thrown away and no response
239 /* Discard service -- ignore data */
242 discard_dg(int s, struct servtab *sep __unused)
244 char buffer[BUFSIZE];
246 (void) read(s, buffer, sizeof(buffer));
249 /* Discard service -- ignore data */
252 discard_stream(int s, struct servtab *sep)
255 char buffer[BUFSIZE];
257 inetd_setproctitle(sep->se_service, s);
259 while ((ret = read(s, buffer, sizeof(buffer))) > 0)
261 if (ret == 0 || errno != EINTR)
268 * RFC862 Echo Protocol. Any data received is sent back to the sender as
272 /* Echo service -- echo data back */
275 echo_dg(int s, struct servtab *sep)
277 char buffer[65536]; /* Should be sizeof(max datagram). */
280 struct sockaddr_storage ss;
283 if ((i = recvfrom(s, buffer, sizeof(buffer), 0,
284 (struct sockaddr *)&ss, &size)) < 0)
287 if (check_loop((struct sockaddr *)&ss, sep))
290 (void) sendto(s, buffer, i, 0, (struct sockaddr *)&ss, size);
293 /* Echo service -- echo data back */
296 echo_stream(int s, struct servtab *sep)
298 char buffer[BUFSIZE];
301 inetd_setproctitle(sep->se_service, s);
302 while ((i = read(s, buffer, sizeof(buffer))) > 0 &&
303 write(s, buffer, i) > 0)
309 * RFC1413 Identification Protocol. Given a TCP port number pair, return a
310 * character string which identifies the owner of that connection on the
311 * server's system. Extended to allow for ~/.fakeid support and ~/.noident
315 /* RFC 1413 says the following are the only errors you can return. */
316 #define ID_INVALID "INVALID-PORT" /* Port number improperly specified. */
317 #define ID_NOUSER "NO-USER" /* Port not in use/not identifable. */
318 #define ID_HIDDEN "HIDDEN-USER" /* Hiden at user's request. */
319 #define ID_UNKNOWN "UNKNOWN-ERROR" /* Everything else. */
321 /* Generic ident_stream error-sending func */
324 iderror(int lport, int fport, int s, const char *er)
328 asprintf(&p, "%d , %d : ERROR : %s\r\n", lport, fport, er);
330 syslog(LOG_ERR, "asprintf: %m");
333 send(s, p, strlen(p), MSG_EOF);
339 /* Ident service (AKA "auth") */
342 ident_stream(int s, struct servtab *sep)
346 struct sockaddr_in sin4[2];
348 struct sockaddr_in6 sin6[2];
350 struct sockaddr_storage ss[2];
352 struct timeval tv = {
356 struct passwd *pw = NULL;
358 char buf[BUFSIZE], *p, **av, *osname = NULL, e;
359 char idbuf[MAXLOGNAME] = ""; /* Big enough to hold uid in decimal. */
363 int c, fflag = 0, nflag = 0, rflag = 0, argc = 0;
364 int gflag = 0, iflag = 0, Fflag = 0, getcredfail = 0, onreadlen;
365 u_short lport, fport;
367 inetd_setproctitle(sep->se_service, s);
369 * Reset getopt() since we are a fork() but not an exec() from
370 * a parent which used getopt() already.
375 * Take the internal argument vector and count it out to make an
376 * argument count for getopt. This can be used for any internal
377 * service to read arguments and use getopt() easily.
379 for (av = sep->se_argv; *av; av++)
386 while ((c = getopt(argc, sep->se_argv, "d:fFgino:rt:")) != -1)
390 strlcpy(idbuf, optarg, sizeof(idbuf));
401 rnd32 = 0; /* Shush, compiler. */
403 * The number of bits in "rnd32" divided
404 * by the number of bits needed per iteration
405 * gives a more optimal way to reload the
406 * random number only when necessary.
408 * 32 bits from arc4random corresponds to
409 * about 6 base-36 digits, so we reseed evey 6.
411 for (i = 0; i < sizeof(idbuf) - 1; i++) {
412 static const char *const base36 =
414 "abcdefghijklmnopqrstuvwxyz";
416 rnd32 = arc4random();
417 idbuf[i] = base36[rnd32 % 36];
435 switch (sscanf(optarg, "%d.%d", &sec, &usec)) {
444 warnx("bad -t argument");
452 if (osname == NULL) {
453 if (uname(&un) == -1)
454 iderror(0, 0, s, ID_UNKNOWN);
459 * We're going to prepare for and execute reception of a
460 * packet of data from the user. The data is in the format
461 * "local_port , foreign_port\r\n" (with local being the
462 * server's port and foreign being the client's.)
464 gettimeofday(&to, NULL);
465 to.tv_sec += tv.tv_sec;
466 to.tv_usec += tv.tv_usec;
467 if (to.tv_usec >= 1000000) {
468 to.tv_usec -= 1000000;
473 bufsiz = sizeof(buf) - 1;
476 gettimeofday(&tv, NULL);
477 tv.tv_sec = to.tv_sec - tv.tv_sec;
478 tv.tv_usec = to.tv_usec - tv.tv_usec;
479 if (tv.tv_usec < 0) {
480 tv.tv_usec += 1000000;
486 if (select(s + 1, &fdset, NULL, NULL, &tv) == -1)
487 iderror(0, 0, s, ID_UNKNOWN);
488 if (ioctl(s, FIONREAD, &onreadlen) == -1)
489 iderror(0, 0, s, ID_UNKNOWN);
490 if ((size_t)onreadlen > bufsiz)
492 ssize = read(s, &buf[size], (size_t)onreadlen);
494 iderror(0, 0, s, ID_UNKNOWN);
499 if (memchr(&buf[size - ssize], '\n', ssize) != NULL)
503 /* Read two characters, and check for a delimiting character */
504 if (sscanf(buf, "%hu , %hu%c", &lport, &fport, &e) != 3 || isdigit(e))
505 iderror(0, 0, s, ID_INVALID);
512 * If not "real" (-r), send a HIDDEN-USER error for everything.
513 * If -d is used to set a fallback username, this is used to
514 * override it, and the fallback is returned instead.
518 iderror(lport, fport, s, ID_HIDDEN);
523 * We take the input and construct an array of two sockaddr_ins
524 * which contain the local address information and foreign
525 * address information, respectively, used to look up the
526 * credentials for the socket (which are returned by the
527 * sysctl "net.inet.tcp.getcred" when we call it.)
529 socklen = sizeof(ss[0]);
530 if (getsockname(s, (struct sockaddr *)&ss[0], &socklen) == -1)
531 iderror(lport, fport, s, ID_UNKNOWN);
532 socklen = sizeof(ss[1]);
533 if (getpeername(s, (struct sockaddr *)&ss[1], &socklen) == -1)
534 iderror(lport, fport, s, ID_UNKNOWN);
535 if (ss[0].ss_family != ss[1].ss_family)
536 iderror(lport, fport, s, ID_UNKNOWN);
538 switch (ss[0].ss_family) {
540 sin4[0] = *(struct sockaddr_in *)&ss[0];
541 sin4[0].sin_port = htons(lport);
542 sin4[1] = *(struct sockaddr_in *)&ss[1];
543 sin4[1].sin_port = htons(fport);
544 if (sysctlbyname("net.inet.tcp.getcred", &uc, &size, sin4,
550 sin6[0] = *(struct sockaddr_in6 *)&ss[0];
551 sin6[0].sin6_port = htons(lport);
552 sin6[1] = *(struct sockaddr_in6 *)&ss[1];
553 sin6[1].sin6_port = htons(fport);
554 if (sysctlbyname("net.inet6.tcp6.getcred", &uc, &size, sin6,
559 default: /* should not reach here */
560 getcredfail = EAFNOSUPPORT;
563 if (getcredfail != 0 || uc.cr_version != XUCRED_VERSION) {
565 iderror(lport, fport, s,
566 getcredfail == ENOENT ? ID_NOUSER : ID_UNKNOWN);
570 /* Look up the pw to get the username and home directory*/
572 pw = getpwuid(uc.cr_uid);
574 iderror(lport, fport, s, errno == 0 ? ID_NOUSER : ID_UNKNOWN);
577 snprintf(idbuf, sizeof(idbuf), "%u", (unsigned)pw->pw_uid);
579 strlcpy(idbuf, pw->pw_name, sizeof(idbuf));
582 * If enabled, we check for a file named ".noident" in the user's
583 * home directory. If found, we return HIDDEN-USER.
586 if (asprintf(&p, "%s/.noident", pw->pw_dir) == -1)
587 iderror(lport, fport, s, ID_UNKNOWN);
588 if (lstat(p, &sb) == 0) {
590 iderror(lport, fport, s, ID_HIDDEN);
596 * Here, if enabled, we read a user's ".fakeid" file in their
597 * home directory. It consists of a line containing the name
604 * Here we set ourself to effectively be the user, so we don't
605 * open any files we have no permission to open, especially
606 * symbolic links to sensitive root-owned files or devices.
608 if (initgroups(pw->pw_name, pw->pw_gid) == -1)
609 iderror(lport, fport, s, ID_UNKNOWN);
610 if (seteuid(pw->pw_uid) == -1)
611 iderror(lport, fport, s, ID_UNKNOWN);
613 * We can't stat() here since that would be a race
615 * Therefore, we open the file we have permissions to open
616 * and if it's not a regular file, we close it and end up
617 * returning the user's real username.
619 if (asprintf(&p, "%s/.fakeid", pw->pw_dir) == -1)
620 iderror(lport, fport, s, ID_UNKNOWN);
621 fakeid_fd = open(p, O_RDONLY | O_NONBLOCK);
623 if (fakeid_fd == -1 || fstat(fakeid_fd, &sb) == -1 ||
624 !S_ISREG(sb.st_mode))
627 if ((ssize = read(fakeid_fd, buf, sizeof(buf) - 1)) < 0)
632 * Usually, the file will have the desired identity
633 * in the form "identity\n". Allow for leading white
634 * space and trailing white space/end of line.
637 p += strspn(p, " \t");
638 p[strcspn(p, " \t\r\n")] = '\0';
639 if (strlen(p) > MAXLOGNAME - 1) /* Too long (including nul)? */
640 p[MAXLOGNAME - 1] = '\0';
643 * If the name is a zero-length string or matches it
644 * the id or name of another user (unless permitted by -F)
645 * then it is invalid.
651 if (p[strspn(p, "0123456789")] == '\0' &&
652 getpwuid(atoi(p)) != NULL)
655 if (getpwnam(p) != NULL)
660 strlcpy(idbuf, p, sizeof(idbuf));
668 /* Finally, we make and send the reply. */
669 if (asprintf(&p, "%d , %d : USERID : %s : %s\r\n", lport, fport, osname,
671 syslog(LOG_ERR, "asprintf: %m");
674 send(s, p, strlen(p), MSG_EOF);
681 * RFC738/868 Time Server.
682 * Return a machine readable date and time, in the form of the
683 * number of seconds since midnight, Jan 1, 1900. Since gettimeofday
684 * returns the number of seconds since midnight, Jan 1, 1970,
685 * we must add 2208988800 seconds to this figure to make up for
686 * some seventy years Bell Labs was asleep.
693 #define OFFSET ((uint32_t)25567 * 24*60*60)
694 return (htonl((uint32_t)(time(NULL) + OFFSET)));
700 machtime_dg(int s, struct servtab *sep)
703 struct sockaddr_storage ss;
707 if (recvfrom(s, (char *)&result, sizeof(result), 0,
708 (struct sockaddr *)&ss, &size) < 0)
711 if (check_loop((struct sockaddr *)&ss, sep))
715 (void) sendto(s, (char *) &result, sizeof(result), 0,
716 (struct sockaddr *)&ss, size);
721 machtime_stream(int s, struct servtab *sep __unused)
726 (void) send(s, (char *) &result, sizeof(result), MSG_EOF);
730 * RFC1078 TCP Port Service Multiplexer (TCPMUX). Service connections to
731 * services based on the service name sent.
733 * Based on TCPMUX.C by Mark K. Lottor November 1988
734 * sri-nic::ps:<mkl>tcpmux.c
737 #define MAX_SERV_LEN (256+2) /* 2 bytes for \r\n */
738 #define strwrite(fd, buf) (void) write(fd, buf, sizeof(buf)-1)
740 static int /* # of characters up to \r,\n or \0 */
741 getline(int fd, char *buf, int len)
747 sigemptyset(&sa.sa_mask);
748 sa.sa_handler = SIG_DFL;
749 sigaction(SIGALRM, &sa, (struct sigaction *)0);
752 n = read(fd, buf, len-count);
759 if (*buf == '\r' || *buf == '\n' || *buf == '\0')
764 } while (count < len);
772 char service[MAX_SERV_LEN+1];
775 /* Get requested service name */
776 if ((len = getline(s, service, MAX_SERV_LEN)) < 0) {
777 strwrite(s, "-Error reading service name\r\n");
783 warnx("tcpmux: someone wants %s", service);
786 * Help is a required command, and lists available services,
789 if (!strcasecmp(service, "help")) {
790 for (sep = servtab; sep; sep = sep->se_next) {
793 (void)write(s,sep->se_service,strlen(sep->se_service));
799 /* Try matching a service in inetd.conf with the request */
800 for (sep = servtab; sep; sep = sep->se_next) {
803 if (!strcasecmp(service, sep->se_service)) {
804 if (ISMUXPLUS(sep)) {
805 strwrite(s, "+Go\r\n");
810 strwrite(s, "-Service not available\r\n");