2 * Copyright (c) 1983, 1993
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.
13 * 3. Neither the name of the University nor the names of its contributors
14 * may be used to endorse or promote products derived from this software
15 * without specific prior written permission.
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 static const char copyright[] =
32 "@(#) Copyright (c) 1983, 1993\n\
33 The Regents of the University of California. All rights reserved.\n";
38 static char sccsid[] = "@(#)tftpd.c 8.1 (Berkeley) 6/4/93";
41 #include <sys/cdefs.h>
42 __FBSDID("$FreeBSD$");
45 * Trivial file transfer protocol server.
47 * This version includes many modifications by Jim Guyton
51 #include <sys/param.h>
52 #include <sys/ioctl.h>
54 #include <sys/socket.h>
56 #include <netinet/in.h>
57 #include <arpa/tftp.h>
71 #include "tftp-file.h"
73 #include "tftp-utils.h"
74 #include "tftp-transfer.h"
75 #include "tftp-options.h"
81 static void tftp_wrq(int peer, char *, ssize_t);
82 static void tftp_rrq(int peer, char *, ssize_t);
85 * Null-terminated directory prefix list for absolute pathname requests and
86 * search list for relative pathname requests.
88 * MAXDIRS should be at least as large as the number of arguments that
89 * inetd allows (currently 20).
92 static struct dirlist {
96 static int suppress_naks;
99 static int create_new = 0;
100 static const char *newfile_format = "%Y%m%d";
101 static int increase_name = 0;
102 static mode_t mask = S_IWGRP | S_IWOTH;
105 static void tftp_recvfile(int peer, const char *mode);
106 static void tftp_xmitfile(int peer, const char *mode);
107 static int validate_access(int peer, char **, int);
108 static char peername[NI_MAXHOST];
112 static struct formats {
122 main(int argc, char *argv[])
126 socklen_t peerlen, len;
129 char *chroot_dir = NULL;
130 struct passwd *nobody;
131 const char *chuser = "nobody";
132 char recvbuffer[MAXPKTSIZE];
133 int allow_ro = 1, allow_wo = 1;
135 tzset(); /* syslog in localtime */
136 acting_as_client = 0;
138 tftp_openlog("tftpd", LOG_PID | LOG_NDELAY, LOG_FTP);
139 while ((ch = getopt(argc, argv, "cCd:F:lnoOp:s:u:U:wW")) != -1) {
148 if (atoi(optarg) != 0)
149 debug += atoi(optarg);
151 debug |= debug_finds(optarg);
154 newfile_format = optarg;
163 options_rfc_enabled = 0;
166 options_extra_enabled = 0;
169 packetdroppercentage = atoi(optarg);
171 "Randomly dropping %d out of 100 packets",
172 packetdroppercentage);
181 mask = strtol(optarg, NULL, 0);
191 tftp_log(LOG_WARNING,
192 "ignoring unknown option -%c", ch);
196 struct dirlist *dirp;
198 /* Get list of directory prefixes. Skip relative pathnames. */
199 for (dirp = dirs; optind < argc && dirp < &dirs[MAXDIRS];
201 if (argv[optind][0] == '/') {
202 dirp->name = argv[optind];
203 dirp->len = strlen(dirp->name);
208 else if (chroot_dir) {
212 if (ipchroot > 0 && chroot_dir == NULL) {
213 tftp_log(LOG_ERR, "-c requires -s");
221 if (ioctl(0, FIONBIO, &on) < 0) {
222 tftp_log(LOG_ERR, "ioctl(FIONBIO): %s", strerror(errno));
227 /* Find out who we are talking to and what we are going to do */
228 peerlen = sizeof(peer_sock);
229 n = recvfrom(0, recvbuffer, MAXPKTSIZE, 0,
230 (struct sockaddr *)&peer_sock, &peerlen);
232 tftp_log(LOG_ERR, "recvfrom: %s", strerror(errno));
235 getnameinfo((struct sockaddr *)&peer_sock, peer_sock.ss_len,
236 peername, sizeof(peername), NULL, 0, NI_NUMERICHOST);
239 * Now that we have read the message out of the UDP
240 * socket, we fork and exit. Thus, inetd will go back
241 * to listening to the tftp port, and the next request
242 * to come in will start up a new instance of tftpd.
244 * We do this so that inetd can run tftpd in "wait" mode.
245 * The problem with tftpd running in "nowait" mode is that
246 * inetd may get one or more successful "selects" on the
247 * tftp port before we do our receive, so more than one
248 * instance of tftpd may be started up. Worse, if tftpd
249 * break before doing the above "recvfrom", inetd would
250 * spawn endless instances, clogging the system.
255 for (i = 1; i < 20; i++) {
260 * flush out to most recently sent request.
262 * This may drop some request, but those
263 * will be resent by the clients when
264 * they timeout. The positive effect of
265 * this flush is to (try to) prevent more
266 * than one tftpd being started up to service
267 * a single request from a single client.
269 peerlen = sizeof peer_sock;
270 i = recvfrom(0, recvbuffer, MAXPKTSIZE, 0,
271 (struct sockaddr *)&peer_sock, &peerlen);
280 tftp_log(LOG_ERR, "fork: %s", strerror(errno));
282 } else if (pid != 0) {
289 * See if the client is allowed to talk to me.
290 * (This needs to be done before the chroot())
293 struct request_info req;
295 request_init(&req, RQ_CLIENT_ADDR, peername, 0);
296 request_set(&req, RQ_DAEMON, "tftpd", 0);
298 if (hosts_access(&req) == 0) {
299 if (debug&DEBUG_ACCESS)
300 tftp_log(LOG_WARNING,
301 "Access denied by 'tftpd' entry "
302 "in /etc/hosts.allow");
305 * Full access might be disabled, but maybe the
306 * client is allowed to do read-only access.
308 request_set(&req, RQ_DAEMON, "tftpd-ro", 0);
309 allow_ro = hosts_access(&req);
311 request_set(&req, RQ_DAEMON, "tftpd-wo", 0);
312 allow_wo = hosts_access(&req);
314 if (allow_ro == 0 && allow_wo == 0) {
315 tftp_log(LOG_WARNING,
316 "Unauthorized access from %s", peername);
320 if (debug&DEBUG_ACCESS) {
322 tftp_log(LOG_WARNING,
323 "But allowed readonly access "
324 "via 'tftpd-ro' entry");
326 tftp_log(LOG_WARNING,
327 "But allowed writeonly access "
328 "via 'tftpd-wo' entry");
331 if (debug&DEBUG_ACCESS)
332 tftp_log(LOG_WARNING,
333 "Full access allowed"
334 "in /etc/hosts.allow");
339 * Since we exit here, we should do that only after the above
340 * recvfrom to keep inetd from constantly forking should there
341 * be a problem. See the above comment about system clogging.
348 struct sockaddr_storage ss;
349 char hbuf[NI_MAXHOST];
352 memcpy(&ss, &peer_sock, peer_sock.ss_len);
353 unmappedaddr((struct sockaddr_in6 *)&ss);
354 getnameinfo((struct sockaddr *)&ss, ss.ss_len,
355 hbuf, sizeof(hbuf), NULL, 0,
357 asprintf(&tempchroot, "%s/%s", chroot_dir, hbuf);
359 statret = stat(tempchroot, &sb);
361 (statret == 0 && (sb.st_mode & S_IFDIR)))
362 chroot_dir = tempchroot;
364 /* Must get this before chroot because /etc might go away */
365 if ((nobody = getpwnam(chuser)) == NULL) {
366 tftp_log(LOG_ERR, "%s: no such user", chuser);
369 if (chroot(chroot_dir)) {
370 tftp_log(LOG_ERR, "chroot: %s: %s",
371 chroot_dir, strerror(errno));
375 if (setgroups(1, &nobody->pw_gid) != 0) {
376 tftp_log(LOG_ERR, "setgroups failed");
379 if (setuid(nobody->pw_uid) != 0) {
380 tftp_log(LOG_ERR, "setuid failed");
385 len = sizeof(me_sock);
386 if (getsockname(0, (struct sockaddr *)&me_sock, &len) == 0) {
387 switch (me_sock.ss_family) {
389 ((struct sockaddr_in *)&me_sock)->sin_port = 0;
392 ((struct sockaddr_in6 *)&me_sock)->sin6_port = 0;
399 memset(&me_sock, 0, sizeof(me_sock));
400 me_sock.ss_family = peer_sock.ss_family;
401 me_sock.ss_len = peer_sock.ss_len;
405 peer = socket(peer_sock.ss_family, SOCK_DGRAM, 0);
407 tftp_log(LOG_ERR, "socket: %s", strerror(errno));
410 if (bind(peer, (struct sockaddr *)&me_sock, me_sock.ss_len) < 0) {
411 tftp_log(LOG_ERR, "bind: %s", strerror(errno));
415 tp = (struct tftphdr *)recvbuffer;
416 tp->th_opcode = ntohs(tp->th_opcode);
417 if (tp->th_opcode == RRQ) {
419 tftp_rrq(peer, tp->th_stuff, n - 1);
421 tftp_log(LOG_WARNING,
422 "%s read access denied", peername);
425 } else if (tp->th_opcode == WRQ) {
427 tftp_wrq(peer, tp->th_stuff, n - 1);
429 tftp_log(LOG_WARNING,
430 "%s write access denied", peername);
434 send_error(peer, EBADOP);
439 reduce_path(char *fn)
443 /* Reduce all "/+./" to "/" (just in case we've got "/./../" later */
444 while ((slash = strstr(fn, "/./")) != NULL) {
445 for (ptr = slash; ptr > fn && ptr[-1] == '/'; ptr--)
452 /* Now reduce all "/something/+../" to "/" */
453 while ((slash = strstr(fn, "/../")) != NULL) {
456 for (ptr = slash; ptr > fn && ptr[-1] == '/'; ptr--)
458 for (ptr--; ptr >= fn; ptr--)
470 parse_header(int peer, char *recvbuffer, ssize_t size,
471 char **filename, char **mode)
480 i = get_field(peer, recvbuffer, size);
482 tftp_log(LOG_ERR, "Bad option - filename too long");
483 send_error(peer, EBADOP);
486 *filename = recvbuffer;
487 tftp_log(LOG_INFO, "Filename: '%s'", *filename);
490 i = get_field(peer, cp, size);
494 /* Find the file transfer mode */
495 for (cp = *mode; *cp; cp++)
498 for (pf = formats; pf->f_mode; pf++)
499 if (strcmp(pf->f_mode, *mode) == 0)
501 if (pf->f_mode == NULL) {
503 "Bad option - Unknown transfer mode (%s)", *mode);
504 send_error(peer, EBADOP);
507 tftp_log(LOG_INFO, "Mode: '%s'", *mode);
513 * WRQ - receive a file from the client
516 tftp_wrq(int peer, char *recvbuffer, ssize_t size)
519 int has_options = 0, ecode;
520 char *filename, *mode;
521 char fnbuf[PATH_MAX];
523 cp = parse_header(peer, recvbuffer, size, &filename, &mode);
524 size -= (cp - recvbuffer) + 1;
526 strlcpy(fnbuf, filename, sizeof(fnbuf));
531 if (options_rfc_enabled)
532 has_options = !parse_options(peer, cp, size);
534 tftp_log(LOG_INFO, "Options found but not enabled");
537 ecode = validate_access(peer, &filename, WRQ);
545 tftp_log(LOG_INFO, "%s: write request for %s: %s", peername,
546 filename, errtomsg(ecode));
550 send_error(peer, ecode);
553 tftp_recvfile(peer, mode);
558 * RRQ - send a file to the client
561 tftp_rrq(int peer, char *recvbuffer, ssize_t size)
564 int has_options = 0, ecode;
565 char *filename, *mode;
566 char fnbuf[PATH_MAX];
568 cp = parse_header(peer, recvbuffer, size, &filename, &mode);
569 size -= (cp - recvbuffer) + 1;
571 strlcpy(fnbuf, filename, sizeof(fnbuf));
576 if (options_rfc_enabled)
577 has_options = !parse_options(peer, cp, size);
579 tftp_log(LOG_INFO, "Options found but not enabled");
582 ecode = validate_access(peer, &filename, RRQ);
586 char lrecvbuffer[MAXPKTSIZE];
587 struct tftphdr *rp = (struct tftphdr *)lrecvbuffer;
590 n = receive_packet(peer, lrecvbuffer, MAXPKTSIZE,
591 NULL, timeoutpacket);
593 if (debug&DEBUG_SIMPLE)
594 tftp_log(LOG_DEBUG, "Aborting: %s",
598 if (rp->th_opcode != ACK) {
599 if (debug&DEBUG_SIMPLE)
601 "Expected ACK, got %s on OACK",
602 packettype(rp->th_opcode));
609 tftp_log(LOG_INFO, "%s: read request for %s: %s", peername,
610 filename, errtomsg(ecode));
614 * Avoid storms of naks to a RRQ broadcast for a relative
615 * bootfile pathname from a diskless Sun.
617 if (suppress_naks && *filename != '/' && ecode == ENOTFOUND)
619 send_error(peer, ecode);
622 tftp_xmitfile(peer, mode);
626 * Find the next value for YYYYMMDD.nn when the file to be written should
627 * be unique. Due to the limitations of nn, we will fail if nn reaches 100.
628 * Besides, that is four updates per hour on a file, which is kind of
632 find_next_name(char *filename, int *fd)
638 char yyyymmdd[MAXPATHLEN];
639 char newname[MAXPATHLEN];
641 /* Create the YYYYMMDD part of the filename */
643 lt = *localtime(&tval);
644 len = strftime(yyyymmdd, sizeof(yyyymmdd), newfile_format, <);
647 "Filename suffix too long (%d characters maximum)",
652 /* Make sure the new filename is not too long */
653 if (strlen(filename) > MAXPATHLEN - len - 5) {
655 "Filename too long (%zd characters, %zd maximum)",
656 strlen(filename), MAXPATHLEN - len - 5);
660 /* Find the first file which doesn't exist */
661 for (i = 0; i < 100; i++) {
662 sprintf(newname, "%s.%s.%02d", filename, yyyymmdd, i);
664 O_WRONLY | O_CREAT | O_EXCL,
665 S_IRUSR | S_IWUSR | S_IRGRP |
666 S_IWGRP | S_IROTH | S_IWOTH);
675 * Validate file access. Since we
676 * have no uid or gid, for now require
677 * file to exist and be publicly
679 * If we were invoked with arguments
680 * from inetd then the file must also be
681 * in one of the given directory prefixes.
682 * Note also, full path name must be
683 * given as we have no login directory.
686 validate_access(int peer, char **filep, int mode)
691 struct dirlist *dirp;
692 static char pathname[MAXPATHLEN];
693 char *filename = *filep;
696 * Prevent tricksters from getting around the directory restrictions
698 if (strstr(filename, "/../"))
701 if (*filename == '/') {
703 * Allow the request if it's in one of the approved locations.
704 * Special case: check the null prefix ("/") by looking
705 * for length = 1 and relying on the arg. processing that
708 for (dirp = dirs; dirp->name != NULL; dirp++) {
709 if (dirp->len == 1 ||
710 (!strncmp(filename, dirp->name, dirp->len) &&
711 filename[dirp->len] == '/'))
714 /* If directory list is empty, allow access to any file */
715 if (dirp->name == NULL && dirp != dirs)
717 if (stat(filename, &stbuf) < 0)
718 return (errno == ENOENT ? ENOTFOUND : EACCESS);
719 if ((stbuf.st_mode & S_IFMT) != S_IFREG)
722 if ((stbuf.st_mode & S_IROTH) == 0)
725 if ((stbuf.st_mode & S_IWOTH) == 0)
732 * Relative file name: search the approved locations for it.
733 * Don't allow write requests that avoid directory
737 if (!strncmp(filename, "../", 3))
741 * If the file exists in one of the directories and isn't
742 * readable, continue looking. However, change the error code
743 * to give an indication that the file exists.
746 for (dirp = dirs; dirp->name != NULL; dirp++) {
747 snprintf(pathname, sizeof(pathname), "%s/%s",
748 dirp->name, filename);
749 if (stat(pathname, &stbuf) == 0 &&
750 (stbuf.st_mode & S_IFMT) == S_IFREG) {
752 if ((stbuf.st_mode & S_IROTH) != 0)
755 if ((stbuf.st_mode & S_IWOTH) != 0)
761 if (dirp->name != NULL)
762 *filep = filename = pathname;
763 else if (mode == RRQ)
765 else if (err != ENOTFOUND || !create_new)
770 * This option is handled here because it (might) require(s) the
773 option_tsize(peer, NULL, mode, &stbuf);
776 fd = open(filename, O_RDONLY);
780 error = find_next_name(filename, &fd);
782 return (error + 100);
785 O_WRONLY | O_TRUNC | O_CREAT,
786 S_IRUSR | S_IWUSR | S_IRGRP |
787 S_IWGRP | S_IROTH | S_IWOTH );
789 fd = open(filename, O_WRONLY | O_TRUNC);
792 return (errno + 100);
793 file = fdopen(fd, (mode == RRQ)? "r":"w");
796 return (errno + 100);
802 tftp_xmitfile(int peer, const char *mode)
806 struct tftp_stats ts;
808 memset(&ts, 0, sizeof(ts));
810 if (debug&DEBUG_SIMPLE)
811 tftp_log(LOG_DEBUG, "Transmitting file");
813 read_init(0, file, mode);
815 tftp_send(peer, &block, &ts);
817 if (debug&DEBUG_SIMPLE)
818 tftp_log(LOG_INFO, "Sent %jd bytes in %jd seconds",
819 (intmax_t)ts.amount, (intmax_t)time(NULL) - now);
823 tftp_recvfile(int peer, const char *mode)
826 struct timeval now1, now2;
827 struct tftp_stats ts;
829 gettimeofday(&now1, NULL);
830 if (debug&DEBUG_SIMPLE)
831 tftp_log(LOG_DEBUG, "Receiving file");
833 write_init(0, file, mode);
836 tftp_receive(peer, &block, &ts, NULL, 0);
838 gettimeofday(&now2, NULL);
840 if (debug&DEBUG_SIMPLE) {
842 if (now1.tv_usec > now2.tv_usec) {
843 now2.tv_usec += 1000000;
847 f = now2.tv_sec - now1.tv_sec +
848 (now2.tv_usec - now1.tv_usec) / 100000.0;
850 "Download of %jd bytes in %d blocks completed after %0.1f seconds\n",
851 (intmax_t)ts.amount, block, f);