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
26 * $FreeBSD: src/usr.sbin/inetd/builtins.c,v 1.19.2.7 2002/07/22 14:05:56 fanf Exp $
27 * $DragonFly: src/usr.sbin/inetd/builtins.c,v 1.5 2004/12/18 22:48:03 swildner Exp $
31 #include <sys/filio.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 unsigned long 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)
122 chargen_dg(int s, struct servtab *sep) /* Character generator */
124 struct sockaddr_storage ss;
128 char text[LINESIZ+2];
136 if (recvfrom(s, text, sizeof(text), 0,
137 (struct sockaddr *)&ss, &size) < 0)
140 if (check_loop((struct sockaddr *)&ss, sep))
143 if ((len = endring - rs) >= LINESIZ)
144 memmove(text, rs, LINESIZ);
146 memmove(text, rs, len);
147 memmove(text + len, ring, LINESIZ - len);
151 text[LINESIZ] = '\r';
152 text[LINESIZ + 1] = '\n';
153 sendto(s, text, sizeof(text), 0, (struct sockaddr *)&ss, size);
158 chargen_stream(int s, struct servtab *sep) /* Character generator */
161 char *rs, text[LINESIZ+2];
163 inetd_setproctitle(sep->se_service, s);
170 text[LINESIZ] = '\r';
171 text[LINESIZ + 1] = '\n';
173 if ((len = endring - rs) >= LINESIZ)
174 memmove(text, rs, LINESIZ);
176 memmove(text, rs, len);
177 memmove(text + len, ring, LINESIZ - len);
181 if (write(s, text, sizeof(text)) != sizeof(text))
188 * RFC867 Daytime Protocol. Sends the current date and time as an ascii
189 * character string without any regard for input.
194 daytime_dg(int s, struct servtab *sep) /* Return human-readable time of day */
198 struct sockaddr_storage ss;
204 if (recvfrom(s, buffer, sizeof(buffer), 0,
205 (struct sockaddr *)&ss, &size) < 0)
208 if (check_loop((struct sockaddr *)&ss, sep))
211 sprintf(buffer, "%.24s\r\n", ctime(&now));
212 sendto(s, buffer, strlen(buffer), 0, (struct sockaddr *)&ss, size);
217 daytime_stream(int s, struct servtab *sep __unused) /* Return human-readable time of day */
224 sprintf(buffer, "%.24s\r\n", ctime(&now));
225 send(s, buffer, strlen(buffer), MSG_EOF);
229 * RFC863 Discard Protocol. Any data received is thrown away and no response
235 discard_dg(int s, struct servtab *sep __unused) /* Discard service -- ignore data */
237 char buffer[BUFSIZE];
239 read(s, buffer, sizeof(buffer));
244 discard_stream(int s, struct servtab *sep) /* Discard service -- ignore data */
247 char buffer[BUFSIZE];
249 inetd_setproctitle(sep->se_service, s);
251 while ((ret = read(s, buffer, sizeof(buffer))) > 0)
253 if (ret == 0 || errno != EINTR)
260 * RFC862 Echo Protocol. Any data received is sent back to the sender as
266 echo_dg(int s, struct servtab *sep) /* Echo service -- echo data back */
268 char buffer[65536]; /* Should be sizeof(max datagram). */
271 struct sockaddr_storage ss;
274 if ((i = recvfrom(s, buffer, sizeof(buffer), 0,
275 (struct sockaddr *)&ss, &size)) < 0)
278 if (check_loop((struct sockaddr *)&ss, sep))
281 sendto(s, buffer, i, 0, (struct sockaddr *)&ss, size);
286 echo_stream(int s, struct servtab *sep) /* Echo service -- echo data back */
288 char buffer[BUFSIZE];
291 inetd_setproctitle(sep->se_service, s);
292 while ((i = read(s, buffer, sizeof(buffer))) > 0 &&
293 write(s, buffer, i) > 0)
299 * RFC1413 Identification Protocol. Given a TCP port number pair, return a
300 * character string which identifies the owner of that connection on the
301 * server's system. Extended to allow for ~/.fakeid support and ~/.noident
305 /* RFC 1413 says the following are the only errors you can return. */
306 #define ID_INVALID "INVALID-PORT" /* Port number improperly specified. */
307 #define ID_NOUSER "NO-USER" /* Port not in use/not identifable. */
308 #define ID_HIDDEN "HIDDEN-USER" /* Hiden at user's request. */
309 #define ID_UNKNOWN "UNKNOWN-ERROR" /* Everything else. */
313 iderror(int lport, int fport, int s, const char *er) /* Generic ident_stream error-sending func */
317 asprintf(&p, "%d , %d : ERROR : %s\r\n", lport, fport, er);
319 syslog(LOG_ERR, "asprintf: %m");
322 send(s, p, strlen(p), MSG_EOF);
330 ident_stream(int s, struct servtab *sep) /* Ident service (AKA "auth") */
334 struct sockaddr_in sin4[2];
336 struct sockaddr_in6 sin6[2];
338 struct sockaddr_storage ss[2];
340 struct timeval tv = {
344 struct passwd *pw = NULL;
346 char buf[BUFSIZE], *p, **av, *osname = NULL, e;
347 char idbuf[MAXLOGNAME] = ""; /* Big enough to hold uid in decimal. */
351 int c, fflag = 0, nflag = 0, rflag = 0, argc = 0;
352 int gflag = 0, iflag = 0, Fflag = 0, getcredfail = 0, onreadlen;
353 u_short lport, fport;
355 inetd_setproctitle(sep->se_service, s);
357 * Reset getopt() since we are a fork() but not an exec() from
358 * a parent which used getopt() already.
363 * Take the internal argument vector and count it out to make an
364 * argument count for getopt. This can be used for any internal
365 * service to read arguments and use getopt() easily.
367 for (av = sep->se_argv; *av; av++)
374 while ((c = getopt(argc, sep->se_argv, "d:fFgino:rt:")) != -1)
378 strlcpy(idbuf, optarg, sizeof(idbuf));
389 rnd32 = 0; /* Shush, compiler. */
391 * The number of bits in "rnd32" divided
392 * by the number of bits needed per iteration
393 * gives a more optimal way to reload the
394 * random number only when necessary.
396 * 32 bits from arc4random corresponds to
397 * about 6 base-36 digits, so we reseed evey 6.
399 for (i = 0; i < sizeof(idbuf) - 1; i++) {
400 static const char *const base36 =
402 "abcdefghijklmnopqrstuvwxyz";
404 rnd32 = arc4random();
405 idbuf[i] = base36[rnd32 % 36];
423 switch (sscanf(optarg, "%d.%d", &sec, &usec)) {
432 warnx("bad -t argument");
440 if (osname == NULL) {
441 if (uname(&un) == -1)
442 iderror(0, 0, s, ID_UNKNOWN);
447 * We're going to prepare for and execute reception of a
448 * packet of data from the user. The data is in the format
449 * "local_port , foreign_port\r\n" (with local being the
450 * server's port and foreign being the client's.)
452 gettimeofday(&to, NULL);
453 to.tv_sec += tv.tv_sec;
454 to.tv_usec += tv.tv_usec;
455 if (to.tv_usec >= 1000000) {
456 to.tv_usec -= 1000000;
461 bufsiz = sizeof(buf) - 1;
464 gettimeofday(&tv, NULL);
465 tv.tv_sec = to.tv_sec - tv.tv_sec;
466 tv.tv_usec = to.tv_usec - tv.tv_usec;
467 if (tv.tv_usec < 0) {
468 tv.tv_usec += 1000000;
474 if (select(s + 1, &fdset, NULL, NULL, &tv) == -1)
475 iderror(0, 0, s, ID_UNKNOWN);
476 if (ioctl(s, FIONREAD, &onreadlen) == -1)
477 iderror(0, 0, s, ID_UNKNOWN);
478 if ((size_t)onreadlen > bufsiz)
480 ssize = read(s, &buf[size], (size_t)onreadlen);
482 iderror(0, 0, s, ID_UNKNOWN);
487 if (memchr(&buf[size - ssize], '\n', ssize) != NULL)
491 /* Read two characters, and check for a delimiting character */
492 if (sscanf(buf, "%hu , %hu%c", &lport, &fport, &e) != 3 || isdigit(e))
493 iderror(0, 0, s, ID_INVALID);
500 * If not "real" (-r), send a HIDDEN-USER error for everything.
501 * If -d is used to set a fallback username, this is used to
502 * override it, and the fallback is returned instead.
506 iderror(lport, fport, s, ID_HIDDEN);
511 * We take the input and construct an array of two sockaddr_ins
512 * which contain the local address information and foreign
513 * address information, respectively, used to look up the
514 * credentials for the socket (which are returned by the
515 * sysctl "net.inet.tcp.getcred" when we call it.)
517 socklen = sizeof(ss[0]);
518 if (getsockname(s, (struct sockaddr *)&ss[0], &socklen) == -1)
519 iderror(lport, fport, s, ID_UNKNOWN);
520 socklen = sizeof(ss[1]);
521 if (getpeername(s, (struct sockaddr *)&ss[1], &socklen) == -1)
522 iderror(lport, fport, s, ID_UNKNOWN);
523 if (ss[0].ss_family != ss[1].ss_family)
524 iderror(lport, fport, s, ID_UNKNOWN);
526 switch (ss[0].ss_family) {
528 sin4[0] = *(struct sockaddr_in *)&ss[0];
529 sin4[0].sin_port = htons(lport);
530 sin4[1] = *(struct sockaddr_in *)&ss[1];
531 sin4[1].sin_port = htons(fport);
532 if (sysctlbyname("net.inet.tcp.getcred", &uc, &size, sin4,
538 sin6[0] = *(struct sockaddr_in6 *)&ss[0];
539 sin6[0].sin6_port = htons(lport);
540 sin6[1] = *(struct sockaddr_in6 *)&ss[1];
541 sin6[1].sin6_port = htons(fport);
542 if (sysctlbyname("net.inet6.tcp6.getcred", &uc, &size, sin6,
547 default: /* should not reach here */
548 getcredfail = EAFNOSUPPORT;
551 if (getcredfail != 0) {
553 iderror(lport, fport, s,
554 getcredfail == ENOENT ? ID_NOUSER : ID_UNKNOWN);
558 /* Look up the pw to get the username and home directory*/
560 pw = getpwuid(uc.cr_uid);
562 iderror(lport, fport, s, errno == 0 ? ID_NOUSER : ID_UNKNOWN);
565 snprintf(idbuf, sizeof(idbuf), "%u", (unsigned)pw->pw_uid);
567 strlcpy(idbuf, pw->pw_name, sizeof(idbuf));
570 * If enabled, we check for a file named ".noident" in the user's
571 * home directory. If found, we return HIDDEN-USER.
574 if (asprintf(&p, "%s/.noident", pw->pw_dir) == -1)
575 iderror(lport, fport, s, ID_UNKNOWN);
576 if (lstat(p, &sb) == 0) {
578 iderror(lport, fport, s, ID_HIDDEN);
584 * Here, if enabled, we read a user's ".fakeid" file in their
585 * home directory. It consists of a line containing the name
592 * Here we set ourself to effectively be the user, so we don't
593 * open any files we have no permission to open, especially
594 * symbolic links to sensitive root-owned files or devices.
596 if (initgroups(pw->pw_name, pw->pw_gid) == -1)
597 iderror(lport, fport, s, ID_UNKNOWN);
598 if (seteuid(pw->pw_uid) == -1)
599 iderror(lport, fport, s, ID_UNKNOWN);
601 * We can't stat() here since that would be a race
603 * Therefore, we open the file we have permissions to open
604 * and if it's not a regular file, we close it and end up
605 * returning the user's real username.
607 if (asprintf(&p, "%s/.fakeid", pw->pw_dir) == -1)
608 iderror(lport, fport, s, ID_UNKNOWN);
609 fakeid_fd = open(p, O_RDONLY | O_NONBLOCK);
611 if (fakeid_fd == -1 || fstat(fakeid_fd, &sb) == -1 ||
612 !S_ISREG(sb.st_mode))
615 if ((ssize = read(fakeid_fd, buf, sizeof(buf) - 1)) < 0)
620 * Usually, the file will have the desired identity
621 * in the form "identity\n". Allow for leading white
622 * space and trailing white space/end of line.
625 p += strspn(p, " \t");
626 p[strcspn(p, " \t\r\n")] = '\0';
627 if (strlen(p) > MAXLOGNAME - 1) /* Too long (including nul)? */
628 p[MAXLOGNAME - 1] = '\0';
631 * If the name is a zero-length string or matches it
632 * the id or name of another user (unless permitted by -F)
633 * then it is invalid.
639 if (p[strspn(p, "0123456789")] == '\0' &&
640 getpwuid(atoi(p)) != NULL)
643 if (getpwnam(p) != NULL)
648 strlcpy(idbuf, p, sizeof(idbuf));
656 /* Finally, we make and send the reply. */
657 if (asprintf(&p, "%d , %d : USERID : %s : %s\r\n", lport, fport, osname,
659 syslog(LOG_ERR, "asprintf: %m");
662 send(s, p, strlen(p), MSG_EOF);
669 * RFC738 Time Server.
670 * Return a machine readable date and time, in the form of the
671 * number of seconds since midnight, Jan 1, 1900. Since gettimeofday
672 * returns the number of seconds since midnight, Jan 1, 1970,
673 * we must add 2208988800 seconds to this figure to make up for
674 * some seventy years Bell Labs was asleep.
682 if (gettimeofday(&tv, NULL) < 0) {
684 warnx("unable to get time of day");
687 #define OFFSET ((u_long)25567 * 24*60*60)
688 return (htonl((long)(tv.tv_sec + OFFSET)));
694 machtime_dg(int s, struct servtab *sep)
696 unsigned long result;
697 struct sockaddr_storage ss;
701 if (recvfrom(s, (char *)&result, sizeof(result), 0,
702 (struct sockaddr *)&ss, &size) < 0)
705 if (check_loop((struct sockaddr *)&ss, sep))
709 sendto(s, (char *) &result, sizeof(result), 0,
710 (struct sockaddr *)&ss, size);
715 machtime_stream(int s, struct servtab *sep __unused)
717 unsigned long result;
720 send(s, (char *) &result, sizeof(result), MSG_EOF);
724 * RFC1078 TCP Port Service Multiplexer (TCPMUX). Service connections to
725 * services based on the service name sent.
727 * Based on TCPMUX.C by Mark K. Lottor November 1988
728 * sri-nic::ps:<mkl>tcpmux.c
731 #define MAX_SERV_LEN (256+2) /* 2 bytes for \r\n */
732 #define strwrite(fd, buf) write(fd, buf, sizeof(buf)-1)
734 static int /* # of characters upto \r,\n or \0 */
735 getline(int fd, char *buf, int len)
741 sigemptyset(&sa.sa_mask);
742 sa.sa_handler = SIG_DFL;
743 sigaction(SIGALRM, &sa, NULL);
746 n = read(fd, buf, len-count);
753 if (*buf == '\r' || *buf == '\n' || *buf == '\0')
758 } while (count < len);
766 char service[MAX_SERV_LEN+1];
769 /* Get requested service name */
770 if ((len = getline(s, service, MAX_SERV_LEN)) < 0) {
771 strwrite(s, "-Error reading service name\r\n");
777 warnx("tcpmux: someone wants %s", service);
780 * Help is a required command, and lists available services,
783 if (!strcasecmp(service, "help")) {
784 for (sep = servtab; sep; sep = sep->se_next) {
787 write(s,sep->se_service,strlen(sep->se_service));
793 /* Try matching a service in inetd.conf with the request */
794 for (sep = servtab; sep; sep = sep->se_next) {
797 if (!strcasecmp(service, sep->se_service)) {
798 if (ISMUXPLUS(sep)) {
799 strwrite(s, "+Go\r\n");
804 strwrite(s, "-Service not available\r\n");