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 1.4 2003/11/16 15:17:36 eirikn Exp $
31 #include <sys/filio.h>
32 #include <sys/ioccom.h>
33 #include <sys/param.h>
35 #include <sys/socket.h>
36 #include <sys/sysctl.h>
37 #include <sys/ucred.h>
39 #include <sys/utsname.h>
56 void chargen_dg(int, struct servtab *);
57 void chargen_stream(int, struct servtab *);
58 void daytime_dg(int, struct servtab *);
59 void daytime_stream(int, struct servtab *);
60 void discard_dg(int, struct servtab *);
61 void discard_stream(int, struct servtab *);
62 void echo_dg(int, struct servtab *);
63 void echo_stream(int, struct servtab *);
64 static int getline(int, char *, int);
65 void iderror(int, int, int, const char *);
66 void ident_stream(int, struct servtab *);
68 unsigned long machtime(void);
69 void machtime_dg(int, struct servtab *);
70 void machtime_stream(int, struct servtab *);
76 struct biltin biltins[] = {
77 /* Echo received data */
78 { "echo", SOCK_STREAM, 1, -1, echo_stream },
79 { "echo", SOCK_DGRAM, 0, 1, echo_dg },
81 /* Internet /dev/null */
82 { "discard", SOCK_STREAM, 1, -1, discard_stream },
83 { "discard", SOCK_DGRAM, 0, 1, discard_dg },
85 /* Return 32 bit time since 1900 */
86 { "time", SOCK_STREAM, 0, -1, machtime_stream },
87 { "time", SOCK_DGRAM, 0, 1, machtime_dg },
89 /* Return human-readable time */
90 { "daytime", SOCK_STREAM, 0, -1, daytime_stream },
91 { "daytime", SOCK_DGRAM, 0, 1, daytime_dg },
93 /* Familiar character generator */
94 { "chargen", SOCK_STREAM, 1, -1, chargen_stream },
95 { "chargen", SOCK_DGRAM, 0, 1, chargen_dg },
97 { "tcpmux", SOCK_STREAM, 1, -1, (bi_fn_t *)tcpmux },
99 { "auth", SOCK_STREAM, 1, -1, ident_stream },
101 { NULL, 0, 0, 0, NULL }
105 * RFC864 Character Generator Protocol. Generates character data without
106 * any regard for input.
116 for (i = 0; i <= 128; ++i)
123 chargen_dg(int s, struct servtab *sep) /* Character generator */
125 struct sockaddr_storage ss;
129 char text[LINESIZ+2];
137 if (recvfrom(s, text, sizeof(text), 0,
138 (struct sockaddr *)&ss, &size) < 0)
141 if (check_loop((struct sockaddr *)&ss, sep))
144 if ((len = endring - rs) >= LINESIZ)
145 memmove(text, rs, LINESIZ);
147 memmove(text, rs, len);
148 memmove(text + len, ring, LINESIZ - len);
152 text[LINESIZ] = '\r';
153 text[LINESIZ + 1] = '\n';
154 (void) sendto(s, text, sizeof(text), 0, (struct sockaddr *)&ss, size);
159 chargen_stream(int s, struct servtab *sep) /* Character generator */
162 char *rs, text[LINESIZ+2];
164 inetd_setproctitle(sep->se_service, s);
171 text[LINESIZ] = '\r';
172 text[LINESIZ + 1] = '\n';
174 if ((len = endring - rs) >= LINESIZ)
175 memmove(text, rs, LINESIZ);
177 memmove(text, rs, len);
178 memmove(text + len, ring, LINESIZ - len);
182 if (write(s, text, sizeof(text)) != sizeof(text))
189 * RFC867 Daytime Protocol. Sends the current date and time as an ascii
190 * character string without any regard for input.
195 daytime_dg(int s, struct servtab *sep) /* Return human-readable time of day */
199 struct sockaddr_storage ss;
202 now = time((time_t *) 0);
205 if (recvfrom(s, buffer, sizeof(buffer), 0,
206 (struct sockaddr *)&ss, &size) < 0)
209 if (check_loop((struct sockaddr *)&ss, sep))
212 (void) sprintf(buffer, "%.24s\r\n", ctime(&now));
213 (void) sendto(s, buffer, strlen(buffer), 0,
214 (struct sockaddr *)&ss, size);
219 daytime_stream(int s, struct servtab *sep __unused) /* Return human-readable time of day */
224 now = time((time_t *) 0);
226 (void) sprintf(buffer, "%.24s\r\n", ctime(&now));
227 (void) send(s, buffer, strlen(buffer), MSG_EOF);
231 * RFC863 Discard Protocol. Any data received is thrown away and no response
237 discard_dg(int s, struct servtab *sep __unused) /* Discard service -- ignore data */
239 char buffer[BUFSIZE];
241 (void) read(s, buffer, sizeof(buffer));
246 discard_stream(int s, struct servtab *sep) /* Discard service -- ignore data */
249 char buffer[BUFSIZE];
251 inetd_setproctitle(sep->se_service, s);
253 while ((ret = read(s, buffer, sizeof(buffer))) > 0)
255 if (ret == 0 || errno != EINTR)
262 * RFC862 Echo Protocol. Any data received is sent back to the sender as
268 echo_dg(int s, struct servtab *sep) /* Echo service -- echo data back */
270 char buffer[65536]; /* Should be sizeof(max datagram). */
273 struct sockaddr_storage ss;
276 if ((i = recvfrom(s, buffer, sizeof(buffer), 0,
277 (struct sockaddr *)&ss, &size)) < 0)
280 if (check_loop((struct sockaddr *)&ss, sep))
283 (void) sendto(s, buffer, i, 0, (struct sockaddr *)&ss, size);
288 echo_stream(int s, struct servtab *sep) /* Echo service -- echo data back */
290 char buffer[BUFSIZE];
293 inetd_setproctitle(sep->se_service, s);
294 while ((i = read(s, buffer, sizeof(buffer))) > 0 &&
295 write(s, buffer, i) > 0)
301 * RFC1413 Identification Protocol. Given a TCP port number pair, return a
302 * character string which identifies the owner of that connection on the
303 * server's system. Extended to allow for ~/.fakeid support and ~/.noident
307 /* RFC 1413 says the following are the only errors you can return. */
308 #define ID_INVALID "INVALID-PORT" /* Port number improperly specified. */
309 #define ID_NOUSER "NO-USER" /* Port not in use/not identifable. */
310 #define ID_HIDDEN "HIDDEN-USER" /* Hiden at user's request. */
311 #define ID_UNKNOWN "UNKNOWN-ERROR" /* Everything else. */
315 iderror(int lport, int fport, int s, const char *er) /* Generic ident_stream error-sending func */
319 asprintf(&p, "%d , %d : ERROR : %s\r\n", lport, fport, er);
321 syslog(LOG_ERR, "asprintf: %m");
324 send(s, p, strlen(p), MSG_EOF);
332 ident_stream(int s, struct servtab *sep) /* Ident service (AKA "auth") */
336 struct sockaddr_in sin4[2];
338 struct sockaddr_in6 sin6[2];
340 struct sockaddr_storage ss[2];
342 struct timeval tv = {
346 struct passwd *pw = NULL;
348 char buf[BUFSIZE], *p, **av, *osname = NULL, e;
349 char idbuf[MAXLOGNAME] = ""; /* Big enough to hold uid in decimal. */
353 int c, fflag = 0, nflag = 0, rflag = 0, argc = 0;
354 int gflag = 0, iflag = 0, Fflag = 0, getcredfail = 0, onreadlen;
355 u_short lport, fport;
357 inetd_setproctitle(sep->se_service, s);
359 * Reset getopt() since we are a fork() but not an exec() from
360 * a parent which used getopt() already.
365 * Take the internal argument vector and count it out to make an
366 * argument count for getopt. This can be used for any internal
367 * service to read arguments and use getopt() easily.
369 for (av = sep->se_argv; *av; av++)
376 while ((c = getopt(argc, sep->se_argv, "d:fFgino:rt:")) != -1)
380 strlcpy(idbuf, optarg, sizeof(idbuf));
391 rnd32 = 0; /* Shush, compiler. */
393 * The number of bits in "rnd32" divided
394 * by the number of bits needed per iteration
395 * gives a more optimal way to reload the
396 * random number only when necessary.
398 * 32 bits from arc4random corresponds to
399 * about 6 base-36 digits, so we reseed evey 6.
401 for (i = 0; i < sizeof(idbuf) - 1; i++) {
402 static const char *const base36 =
404 "abcdefghijklmnopqrstuvwxyz";
406 rnd32 = arc4random();
407 idbuf[i] = base36[rnd32 % 36];
425 switch (sscanf(optarg, "%d.%d", &sec, &usec)) {
434 warnx("bad -t argument");
442 if (osname == NULL) {
443 if (uname(&un) == -1)
444 iderror(0, 0, s, ID_UNKNOWN);
449 * We're going to prepare for and execute reception of a
450 * packet of data from the user. The data is in the format
451 * "local_port , foreign_port\r\n" (with local being the
452 * server's port and foreign being the client's.)
454 gettimeofday(&to, NULL);
455 to.tv_sec += tv.tv_sec;
456 to.tv_usec += tv.tv_usec;
457 if (to.tv_usec >= 1000000) {
458 to.tv_usec -= 1000000;
463 bufsiz = sizeof(buf) - 1;
466 gettimeofday(&tv, NULL);
467 tv.tv_sec = to.tv_sec - tv.tv_sec;
468 tv.tv_usec = to.tv_usec - tv.tv_usec;
469 if (tv.tv_usec < 0) {
470 tv.tv_usec += 1000000;
476 if (select(s + 1, &fdset, NULL, NULL, &tv) == -1)
477 iderror(0, 0, s, ID_UNKNOWN);
478 if (ioctl(s, FIONREAD, &onreadlen) == -1)
479 iderror(0, 0, s, ID_UNKNOWN);
480 if ((size_t)onreadlen > bufsiz)
482 ssize = read(s, &buf[size], (size_t)onreadlen);
484 iderror(0, 0, s, ID_UNKNOWN);
489 if (memchr(&buf[size - ssize], '\n', ssize) != NULL)
493 /* Read two characters, and check for a delimiting character */
494 if (sscanf(buf, "%hu , %hu%c", &lport, &fport, &e) != 3 || isdigit(e))
495 iderror(0, 0, s, ID_INVALID);
502 * If not "real" (-r), send a HIDDEN-USER error for everything.
503 * If -d is used to set a fallback username, this is used to
504 * override it, and the fallback is returned instead.
508 iderror(lport, fport, s, ID_HIDDEN);
513 * We take the input and construct an array of two sockaddr_ins
514 * which contain the local address information and foreign
515 * address information, respectively, used to look up the
516 * credentials for the socket (which are returned by the
517 * sysctl "net.inet.tcp.getcred" when we call it.)
519 socklen = sizeof(ss[0]);
520 if (getsockname(s, (struct sockaddr *)&ss[0], &socklen) == -1)
521 iderror(lport, fport, s, ID_UNKNOWN);
522 socklen = sizeof(ss[1]);
523 if (getpeername(s, (struct sockaddr *)&ss[1], &socklen) == -1)
524 iderror(lport, fport, s, ID_UNKNOWN);
525 if (ss[0].ss_family != ss[1].ss_family)
526 iderror(lport, fport, s, ID_UNKNOWN);
528 switch (ss[0].ss_family) {
530 sin4[0] = *(struct sockaddr_in *)&ss[0];
531 sin4[0].sin_port = htons(lport);
532 sin4[1] = *(struct sockaddr_in *)&ss[1];
533 sin4[1].sin_port = htons(fport);
534 if (sysctlbyname("net.inet.tcp.getcred", &uc, &size, sin4,
540 sin6[0] = *(struct sockaddr_in6 *)&ss[0];
541 sin6[0].sin6_port = htons(lport);
542 sin6[1] = *(struct sockaddr_in6 *)&ss[1];
543 sin6[1].sin6_port = htons(fport);
544 if (sysctlbyname("net.inet6.tcp6.getcred", &uc, &size, sin6,
549 default: /* should not reach here */
550 getcredfail = EAFNOSUPPORT;
553 if (getcredfail != 0) {
555 iderror(lport, fport, s,
556 getcredfail == ENOENT ? ID_NOUSER : ID_UNKNOWN);
560 /* Look up the pw to get the username and home directory*/
562 pw = getpwuid(uc.cr_uid);
564 iderror(lport, fport, s, errno == 0 ? ID_NOUSER : ID_UNKNOWN);
567 snprintf(idbuf, sizeof(idbuf), "%u", (unsigned)pw->pw_uid);
569 strlcpy(idbuf, pw->pw_name, sizeof(idbuf));
572 * If enabled, we check for a file named ".noident" in the user's
573 * home directory. If found, we return HIDDEN-USER.
576 if (asprintf(&p, "%s/.noident", pw->pw_dir) == -1)
577 iderror(lport, fport, s, ID_UNKNOWN);
578 if (lstat(p, &sb) == 0) {
580 iderror(lport, fport, s, ID_HIDDEN);
586 * Here, if enabled, we read a user's ".fakeid" file in their
587 * home directory. It consists of a line containing the name
594 * Here we set ourself to effectively be the user, so we don't
595 * open any files we have no permission to open, especially
596 * symbolic links to sensitive root-owned files or devices.
598 if (initgroups(pw->pw_name, pw->pw_gid) == -1)
599 iderror(lport, fport, s, ID_UNKNOWN);
600 if (seteuid(pw->pw_uid) == -1)
601 iderror(lport, fport, s, ID_UNKNOWN);
603 * We can't stat() here since that would be a race
605 * Therefore, we open the file we have permissions to open
606 * and if it's not a regular file, we close it and end up
607 * returning the user's real username.
609 if (asprintf(&p, "%s/.fakeid", pw->pw_dir) == -1)
610 iderror(lport, fport, s, ID_UNKNOWN);
611 fakeid_fd = open(p, O_RDONLY | O_NONBLOCK);
613 if (fakeid_fd == -1 || fstat(fakeid_fd, &sb) == -1 ||
614 !S_ISREG(sb.st_mode))
617 if ((ssize = read(fakeid_fd, buf, sizeof(buf) - 1)) < 0)
622 * Usually, the file will have the desired identity
623 * in the form "identity\n". Allow for leading white
624 * space and trailing white space/end of line.
627 p += strspn(p, " \t");
628 p[strcspn(p, " \t\r\n")] = '\0';
629 if (strlen(p) > MAXLOGNAME - 1) /* Too long (including nul)? */
630 p[MAXLOGNAME - 1] = '\0';
633 * If the name is a zero-length string or matches it
634 * the id or name of another user (unless permitted by -F)
635 * then it is invalid.
641 if (p[strspn(p, "0123456789")] == '\0' &&
642 getpwuid(atoi(p)) != NULL)
645 if (getpwnam(p) != NULL)
650 strlcpy(idbuf, p, sizeof(idbuf));
658 /* Finally, we make and send the reply. */
659 if (asprintf(&p, "%d , %d : USERID : %s : %s\r\n", lport, fport, osname,
661 syslog(LOG_ERR, "asprintf: %m");
664 send(s, p, strlen(p), MSG_EOF);
671 * RFC738 Time Server.
672 * Return a machine readable date and time, in the form of the
673 * number of seconds since midnight, Jan 1, 1900. Since gettimeofday
674 * returns the number of seconds since midnight, Jan 1, 1970,
675 * we must add 2208988800 seconds to this figure to make up for
676 * some seventy years Bell Labs was asleep.
684 if (gettimeofday(&tv, (struct timezone *)NULL) < 0) {
686 warnx("unable to get time of day");
689 #define OFFSET ((u_long)25567 * 24*60*60)
690 return (htonl((long)(tv.tv_sec + OFFSET)));
696 machtime_dg(int s, struct servtab *sep)
698 unsigned long result;
699 struct sockaddr_storage ss;
703 if (recvfrom(s, (char *)&result, sizeof(result), 0,
704 (struct sockaddr *)&ss, &size) < 0)
707 if (check_loop((struct sockaddr *)&ss, sep))
711 (void) sendto(s, (char *) &result, sizeof(result), 0,
712 (struct sockaddr *)&ss, size);
717 machtime_stream(int s, struct servtab *sep __unused)
719 unsigned long result;
722 (void) send(s, (char *) &result, sizeof(result), MSG_EOF);
726 * RFC1078 TCP Port Service Multiplexer (TCPMUX). Service connections to
727 * services based on the service name sent.
729 * Based on TCPMUX.C by Mark K. Lottor November 1988
730 * sri-nic::ps:<mkl>tcpmux.c
733 #define MAX_SERV_LEN (256+2) /* 2 bytes for \r\n */
734 #define strwrite(fd, buf) (void) write(fd, buf, sizeof(buf)-1)
736 static int /* # of characters upto \r,\n or \0 */
737 getline(int fd, char *buf, int len)
743 sigemptyset(&sa.sa_mask);
744 sa.sa_handler = SIG_DFL;
745 sigaction(SIGALRM, &sa, (struct sigaction *)0);
748 n = read(fd, buf, len-count);
755 if (*buf == '\r' || *buf == '\n' || *buf == '\0')
760 } while (count < len);
768 char service[MAX_SERV_LEN+1];
771 /* Get requested service name */
772 if ((len = getline(s, service, MAX_SERV_LEN)) < 0) {
773 strwrite(s, "-Error reading service name\r\n");
779 warnx("tcpmux: someone wants %s", service);
782 * Help is a required command, and lists available services,
785 if (!strcasecmp(service, "help")) {
786 for (sep = servtab; sep; sep = sep->se_next) {
789 (void)write(s,sep->se_service,strlen(sep->se_service));
795 /* Try matching a service in inetd.conf with the request */
796 for (sep = servtab; sep; sep = sep->se_next) {
799 if (!strcasecmp(service, sep->se_service)) {
800 if (ISMUXPLUS(sep)) {
801 strwrite(s, "+Go\r\n");
806 strwrite(s, "-Service not available\r\n");