68#include <stdio.h>
69#include <stdlib.h>
70#include <string.h>
71#include <syslog.h>
72#include <tcpd.h>
73#include <unistd.h>
74
75#include "tftp-file.h"
76#include "tftp-io.h"
77#include "tftp-utils.h"
78#include "tftp-transfer.h"
79#include "tftp-options.h"
80
81static void tftp_wrq(int peer, char *, ssize_t);
82static void tftp_rrq(int peer, char *, ssize_t);
83
84/*
85 * Null-terminated directory prefix list for absolute pathname requests and
86 * search list for relative pathname requests.
87 *
88 * MAXDIRS should be at least as large as the number of arguments that
89 * inetd allows (currently 20).
90 */
91#define MAXDIRS 20
92static struct dirlist {
93 const char *name;
94 int len;
95} dirs[MAXDIRS+1];
96static int suppress_naks;
97static int logging;
98static int ipchroot;
99static int create_new = 0;
100static const char *newfile_format = "%Y%m%d";
101static int increase_name = 0;
102static mode_t mask = S_IWGRP | S_IWOTH;
103
104struct formats;
105static void tftp_recvfile(int peer, const char *mode);
106static void tftp_xmitfile(int peer, const char *mode);
107static int validate_access(int peer, char **, int);
108static char peername[NI_MAXHOST];
109
110static FILE *file;
111
112static struct formats {
113 const char *f_mode;
114 int f_convert;
115} formats[] = {
116 { "netascii", 1 },
117 { "octet", 0 },
118 { NULL, 0 }
119};
120
121int
122main(int argc, char *argv[])
123{
124 struct tftphdr *tp;
125 int peer;
126 socklen_t peerlen, len;
127 ssize_t n;
128 int ch;
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;
134
135 tzset(); /* syslog in localtime */
136 acting_as_client = 0;
137
138 tftp_openlog("tftpd", LOG_PID | LOG_NDELAY, LOG_FTP);
139 while ((ch = getopt(argc, argv, "cCd:F:lnoOp:s:u:U:wW")) != -1) {
140 switch (ch) {
141 case 'c':
142 ipchroot = 1;
143 break;
144 case 'C':
145 ipchroot = 2;
146 break;
147 case 'd':
148 if (atoi(optarg) != 0)
149 debug += atoi(optarg);
150 else
151 debug |= debug_finds(optarg);
152 break;
153 case 'F':
154 newfile_format = optarg;
155 break;
156 case 'l':
157 logging = 1;
158 break;
159 case 'n':
160 suppress_naks = 1;
161 break;
162 case 'o':
163 options_rfc_enabled = 0;
164 break;
165 case 'O':
166 options_extra_enabled = 0;
167 break;
168 case 'p':
169 packetdroppercentage = atoi(optarg);
170 tftp_log(LOG_INFO,
171 "Randomly dropping %d out of 100 packets",
172 packetdroppercentage);
173 break;
174 case 's':
175 chroot_dir = optarg;
176 break;
177 case 'u':
178 chuser = optarg;
179 break;
180 case 'U':
181 mask = strtol(optarg, NULL, 0);
182 break;
183 case 'w':
184 create_new = 1;
185 break;
186 case 'W':
187 create_new = 1;
188 increase_name = 1;
189 break;
190 default:
191 tftp_log(LOG_WARNING,
192 "ignoring unknown option -%c", ch);
193 }
194 }
195 if (optind < argc) {
196 struct dirlist *dirp;
197
198 /* Get list of directory prefixes. Skip relative pathnames. */
199 for (dirp = dirs; optind < argc && dirp < &dirs[MAXDIRS];
200 optind++) {
201 if (argv[optind][0] == '/') {
202 dirp->name = argv[optind];
203 dirp->len = strlen(dirp->name);
204 dirp++;
205 }
206 }
207 }
208 else if (chroot_dir) {
209 dirs->name = "/";
210 dirs->len = 1;
211 }
212 if (ipchroot > 0 && chroot_dir == NULL) {
213 tftp_log(LOG_ERR, "-c requires -s");
214 exit(1);
215 }
216
217 umask(mask);
218
219 {
220 int on = 1;
221 if (ioctl(0, FIONBIO, &on) < 0) {
222 tftp_log(LOG_ERR, "ioctl(FIONBIO): %s", strerror(errno));
223 exit(1);
224 }
225 }
226
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);
231 if (n < 0) {
232 tftp_log(LOG_ERR, "recvfrom: %s", strerror(errno));
233 exit(1);
234 }
235 getnameinfo((struct sockaddr *)&peer_sock, peer_sock.ss_len,
236 peername, sizeof(peername), NULL, 0, NI_NUMERICHOST);
237
238 /*
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.
243 *
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.
251 */
252 {
253 int i, pid;
254
255 for (i = 1; i < 20; i++) {
256 pid = fork();
257 if (pid < 0) {
258 sleep(i);
259 /*
260 * flush out to most recently sent request.
261 *
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.
268 */
269 peerlen = sizeof peer_sock;
270 i = recvfrom(0, recvbuffer, MAXPKTSIZE, 0,
271 (struct sockaddr *)&peer_sock, &peerlen);
272 if (i > 0) {
273 n = i;
274 }
275 } else {
276 break;
277 }
278 }
279 if (pid < 0) {
280 tftp_log(LOG_ERR, "fork: %s", strerror(errno));
281 exit(1);
282 } else if (pid != 0) {
283 exit(0);
284 }
285 }
286
287 /*
288 * See if the client is allowed to talk to me.
289 * (This needs to be done before the chroot())
290 */
291 {
292 struct request_info req;
293
294 request_init(&req, RQ_CLIENT_ADDR, peername, 0);
295 request_set(&req, RQ_DAEMON, "tftpd", 0);
296
297 if (hosts_access(&req) == 0) {
298 if (debug&DEBUG_ACCESS)
299 tftp_log(LOG_WARNING,
300 "Access denied by 'tftpd' entry "
301 "in /etc/hosts.allow");
302
303 /*
304 * Full access might be disabled, but maybe the
305 * client is allowed to do read-only access.
306 */
307 request_set(&req, RQ_DAEMON, "tftpd-ro", 0);
308 allow_ro = hosts_access(&req);
309
310 request_set(&req, RQ_DAEMON, "tftpd-wo", 0);
311 allow_wo = hosts_access(&req);
312
313 if (allow_ro == 0 && allow_wo == 0) {
314 tftp_log(LOG_WARNING,
315 "Unauthorized access from %s", peername);
316 exit(1);
317 }
318
319 if (debug&DEBUG_ACCESS) {
320 if (allow_ro)
321 tftp_log(LOG_WARNING,
322 "But allowed readonly access "
323 "via 'tftpd-ro' entry");
324 if (allow_wo)
325 tftp_log(LOG_WARNING,
326 "But allowed writeonly access "
327 "via 'tftpd-wo' entry");
328 }
329 } else
330 if (debug&DEBUG_ACCESS)
331 tftp_log(LOG_WARNING,
332 "Full access allowed"
333 "in /etc/hosts.allow");
334 }
335
336 /*
337 * Since we exit here, we should do that only after the above
338 * recvfrom to keep inetd from constantly forking should there
339 * be a problem. See the above comment about system clogging.
340 */
341 if (chroot_dir) {
342 if (ipchroot > 0) {
343 char *tempchroot;
344 struct stat sb;
345 int statret;
346 struct sockaddr_storage ss;
347 char hbuf[NI_MAXHOST];
348
349 statret = -1;
350 memcpy(&ss, &peer_sock, peer_sock.ss_len);
351 unmappedaddr((struct sockaddr_in6 *)&ss);
352 getnameinfo((struct sockaddr *)&ss, ss.ss_len,
353 hbuf, sizeof(hbuf), NULL, 0,
354 NI_NUMERICHOST);
355 asprintf(&tempchroot, "%s/%s", chroot_dir, hbuf);
356 if (ipchroot == 2)
357 statret = stat(tempchroot, &sb);
358 if (ipchroot == 1 ||
359 (statret == 0 && (sb.st_mode & S_IFDIR)))
360 chroot_dir = tempchroot;
361 }
362 /* Must get this before chroot because /etc might go away */
363 if ((nobody = getpwnam(chuser)) == NULL) {
364 tftp_log(LOG_ERR, "%s: no such user", chuser);
365 exit(1);
366 }
367 if (chroot(chroot_dir)) {
368 tftp_log(LOG_ERR, "chroot: %s: %s",
369 chroot_dir, strerror(errno));
370 exit(1);
371 }
372 chdir("/");
373 setgroups(1, &nobody->pw_gid);
374 if (setuid(nobody->pw_uid) != 0) {
375 tftp_log(LOG_ERR, "setuid failed");
376 exit(1);
377 }
378 }
379
380 len = sizeof(me_sock);
381 if (getsockname(0, (struct sockaddr *)&me_sock, &len) == 0) {
382 switch (me_sock.ss_family) {
383 case AF_INET:
384 ((struct sockaddr_in *)&me_sock)->sin_port = 0;
385 break;
386 case AF_INET6:
387 ((struct sockaddr_in6 *)&me_sock)->sin6_port = 0;
388 break;
389 default:
390 /* unsupported */
391 break;
392 }
393 } else {
394 memset(&me_sock, 0, sizeof(me_sock));
395 me_sock.ss_family = peer_sock.ss_family;
396 me_sock.ss_len = peer_sock.ss_len;
397 }
398 close(0);
399 close(1);
400 peer = socket(peer_sock.ss_family, SOCK_DGRAM, 0);
401 if (peer < 0) {
402 tftp_log(LOG_ERR, "socket: %s", strerror(errno));
403 exit(1);
404 }
405 if (bind(peer, (struct sockaddr *)&me_sock, me_sock.ss_len) < 0) {
406 tftp_log(LOG_ERR, "bind: %s", strerror(errno));
407 exit(1);
408 }
409
410 tp = (struct tftphdr *)recvbuffer;
411 tp->th_opcode = ntohs(tp->th_opcode);
412 if (tp->th_opcode == RRQ) {
413 if (allow_ro)
414 tftp_rrq(peer, tp->th_stuff, n - 1);
415 else {
416 tftp_log(LOG_WARNING,
417 "%s read access denied", peername);
418 exit(1);
419 }
420 }
421 if (tp->th_opcode == WRQ) {
422 if (allow_wo)
423 tftp_wrq(peer, tp->th_stuff, n - 1);
424 else {
425 tftp_log(LOG_WARNING,
426 "%s write access denied", peername);
427 exit(1);
428 }
429 }
430 exit(1);
431}
432
433static void
434reduce_path(char *fn)
435{
436 char *slash, *ptr;
437
438 /* Reduce all "/+./" to "/" (just in case we've got "/./../" later */
439 while ((slash = strstr(fn, "/./")) != NULL) {
440 for (ptr = slash; ptr > fn && ptr[-1] == '/'; ptr--)
441 ;
442 slash += 2;
443 while (*slash)
444 *++ptr = *++slash;
445 }
446
447 /* Now reduce all "/something/+../" to "/" */
448 while ((slash = strstr(fn, "/../")) != NULL) {
449 if (slash == fn)
450 break;
451 for (ptr = slash; ptr > fn && ptr[-1] == '/'; ptr--)
452 ;
453 for (ptr--; ptr >= fn; ptr--)
454 if (*ptr == '/')
455 break;
456 if (ptr < fn)
457 break;
458 slash += 3;
459 while (*slash)
460 *++ptr = *++slash;
461 }
462}
463
464static char *
465parse_header(int peer, char *recvbuffer, ssize_t size,
466 char **filename, char **mode)
467{
468 char *cp;
469 int i;
470 struct formats *pf;
471
472 *mode = NULL;
473 cp = recvbuffer;
474
475 i = get_field(peer, recvbuffer, size);
476 if (i >= PATH_MAX) {
477 tftp_log(LOG_ERR, "Bad option - filename too long");
478 send_error(peer, EBADOP);
479 exit(1);
480 }
481 *filename = recvbuffer;
482 tftp_log(LOG_INFO, "Filename: '%s'", *filename);
483 cp += i;
484
485 i = get_field(peer, cp, size);
486 *mode = cp;
487 cp += i;
488
489 /* Find the file transfer mode */
490 for (cp = *mode; *cp; cp++)
491 if (isupper(*cp))
492 *cp = tolower(*cp);
493 for (pf = formats; pf->f_mode; pf++)
494 if (strcmp(pf->f_mode, *mode) == 0)
495 break;
496 if (pf->f_mode == NULL) {
497 tftp_log(LOG_ERR,
498 "Bad option - Unknown transfer mode (%s)", *mode);
499 send_error(peer, EBADOP);
500 exit(1);
501 }
502 tftp_log(LOG_INFO, "Mode: '%s'", *mode);
503
504 return (cp + 1);
505}
506
507/*
508 * WRQ - receive a file from the client
509 */
510void
511tftp_wrq(int peer, char *recvbuffer, ssize_t size)
512{
513 char *cp;
514 int has_options = 0, ecode;
515 char *filename, *mode;
516 char fnbuf[PATH_MAX];
517
518 cp = parse_header(peer, recvbuffer, size, &filename, &mode);
519 size -= (cp - recvbuffer) + 1;
520
521 strcpy(fnbuf, filename);
522 reduce_path(fnbuf);
523 filename = fnbuf;
524
525 if (size > 0) {
526 if (options_rfc_enabled)
527 has_options = !parse_options(peer, cp, size);
528 else
529 tftp_log(LOG_INFO, "Options found but not enabled");
530 }
531
532 ecode = validate_access(peer, &filename, WRQ);
533 if (ecode == 0) {
534 if (has_options)
535 send_oack(peer);
536 else
537 send_ack(peer, 0);
538 }
539 if (logging) {
540 tftp_log(LOG_INFO, "%s: write request for %s: %s", peername,
541 filename, errtomsg(ecode));
542 }
543
544 tftp_recvfile(peer, mode);
545 exit(0);
546}
547
548/*
549 * RRQ - send a file to the client
550 */
551void
552tftp_rrq(int peer, char *recvbuffer, ssize_t size)
553{
554 char *cp;
555 int has_options = 0, ecode;
556 char *filename, *mode;
557 char fnbuf[PATH_MAX];
558
559 cp = parse_header(peer, recvbuffer, size, &filename, &mode);
560 size -= (cp - recvbuffer) + 1;
561
562 strcpy(fnbuf, filename);
563 reduce_path(fnbuf);
564 filename = fnbuf;
565
566 if (size > 0) {
567 if (options_rfc_enabled)
568 has_options = !parse_options(peer, cp, size);
569 else
570 tftp_log(LOG_INFO, "Options found but not enabled");
571 }
572
573 ecode = validate_access(peer, &filename, RRQ);
574 if (ecode == 0) {
575 if (has_options) {
576 int n;
577 char lrecvbuffer[MAXPKTSIZE];
578 struct tftphdr *rp = (struct tftphdr *)lrecvbuffer;
579
580 send_oack(peer);
581 n = receive_packet(peer, lrecvbuffer, MAXPKTSIZE,
582 NULL, timeoutpacket);
583 if (n < 0) {
584 if (debug&DEBUG_SIMPLE)
585 tftp_log(LOG_DEBUG, "Aborting: %s",
586 rp_strerror(n));
587 return;
588 }
589 if (rp->th_opcode != ACK) {
590 if (debug&DEBUG_SIMPLE)
591 tftp_log(LOG_DEBUG,
592 "Expected ACK, got %s on OACK",
593 packettype(rp->th_opcode));
594 return;
595 }
596 }
597 }
598
599 if (logging)
600 tftp_log(LOG_INFO, "%s: read request for %s: %s", peername,
601 filename, errtomsg(ecode));
602
603 if (ecode) {
604 /*
605 * Avoid storms of naks to a RRQ broadcast for a relative
606 * bootfile pathname from a diskless Sun.
607 */
608 if (suppress_naks && *filename != '/' && ecode == ENOTFOUND)
609 exit(0);
610 send_error(peer, ecode);
611 exit(1);
612 }
613 tftp_xmitfile(peer, mode);
614}
615
616/*
617 * Find the next value for YYYYMMDD.nn when the file to be written should
618 * be unique. Due to the limitations of nn, we will fail if nn reaches 100.
619 * Besides, that is four updates per hour on a file, which is kind of
620 * execessive anyway.
621 */
622static int
623find_next_name(char *filename, int *fd)
624{
625 int i;
626 time_t tval;
627 size_t len;
628 struct tm lt;
629 char yyyymmdd[MAXPATHLEN];
630 char newname[MAXPATHLEN];
631
632 /* Create the YYYYMMDD part of the filename */
633 time(&tval);
634 lt = *localtime(&tval);
635 len = strftime(yyyymmdd, sizeof(yyyymmdd), newfile_format, <);
636 if (len == 0) {
637 syslog(LOG_WARNING,
638 "Filename suffix too long (%d characters maximum)",
639 MAXPATHLEN);
640 return (EACCESS);
641 }
642
643 /* Make sure the new filename is not too long */
644 if (strlen(filename) > MAXPATHLEN - len - 5) {
645 syslog(LOG_WARNING,
646 "Filename too long (%zd characters, %zd maximum)",
647 strlen(filename), MAXPATHLEN - len - 5);
648 return (EACCESS);
649 }
650
651 /* Find the first file which doesn't exist */
652 for (i = 0; i < 100; i++) {
653 sprintf(newname, "%s.%s.%02d", filename, yyyymmdd, i);
654 *fd = open(newname,
655 O_WRONLY | O_CREAT | O_EXCL,
656 S_IRUSR | S_IWUSR | S_IRGRP |
657 S_IWGRP | S_IROTH | S_IWOTH);
658 if (*fd > 0)
659 return 0;
660 }
661
662 return (EEXIST);
663}
664
665/*
666 * Validate file access. Since we
667 * have no uid or gid, for now require
668 * file to exist and be publicly
669 * readable/writable.
670 * If we were invoked with arguments
671 * from inetd then the file must also be
672 * in one of the given directory prefixes.
673 * Note also, full path name must be
674 * given as we have no login directory.
675 */
676int
677validate_access(int peer, char **filep, int mode)
678{
679 struct stat stbuf;
680 int fd;
681 int error;
682 struct dirlist *dirp;
683 static char pathname[MAXPATHLEN];
684 char *filename = *filep;
685
686 /*
687 * Prevent tricksters from getting around the directory restrictions
688 */
689 if (strstr(filename, "/../"))
690 return (EACCESS);
691
692 if (*filename == '/') {
693 /*
694 * Allow the request if it's in one of the approved locations.
695 * Special case: check the null prefix ("/") by looking
696 * for length = 1 and relying on the arg. processing that
697 * it's a /.
698 */
699 for (dirp = dirs; dirp->name != NULL; dirp++) {
700 if (dirp->len == 1 ||
701 (!strncmp(filename, dirp->name, dirp->len) &&
702 filename[dirp->len] == '/'))
703 break;
704 }
705 /* If directory list is empty, allow access to any file */
706 if (dirp->name == NULL && dirp != dirs)
707 return (EACCESS);
708 if (stat(filename, &stbuf) < 0)
709 return (errno == ENOENT ? ENOTFOUND : EACCESS);
710 if ((stbuf.st_mode & S_IFMT) != S_IFREG)
711 return (ENOTFOUND);
712 if (mode == RRQ) {
713 if ((stbuf.st_mode & S_IROTH) == 0)
714 return (EACCESS);
715 } else {
716 if ((stbuf.st_mode & S_IWOTH) == 0)
717 return (EACCESS);
718 }
719 } else {
720 int err;
721
722 /*
723 * Relative file name: search the approved locations for it.
724 * Don't allow write requests that avoid directory
725 * restrictions.
726 */
727
728 if (!strncmp(filename, "../", 3))
729 return (EACCESS);
730
731 /*
732 * If the file exists in one of the directories and isn't
733 * readable, continue looking. However, change the error code
734 * to give an indication that the file exists.
735 */
736 err = ENOTFOUND;
737 for (dirp = dirs; dirp->name != NULL; dirp++) {
738 snprintf(pathname, sizeof(pathname), "%s/%s",
739 dirp->name, filename);
740 if (stat(pathname, &stbuf) == 0 &&
741 (stbuf.st_mode & S_IFMT) == S_IFREG) {
742 if ((stbuf.st_mode & S_IROTH) != 0) {
743 break;
744 }
745 err = EACCESS;
746 }
747 }
748 if (dirp->name != NULL)
749 *filep = filename = pathname;
750 else if (mode == RRQ)
751 return (err);
752 }
753
754 /*
755 * This option is handled here because it (might) require(s) the
756 * size of the file.
757 */
758 option_tsize(peer, NULL, mode, &stbuf);
759
760 if (mode == RRQ)
761 fd = open(filename, O_RDONLY);
762 else {
763 if (create_new) {
764 if (increase_name) {
765 error = find_next_name(filename, &fd);
766 if (error > 0)
767 return (error + 100);
768 } else
769 fd = open(filename,
770 O_WRONLY | O_TRUNC | O_CREAT,
771 S_IRUSR | S_IWUSR | S_IRGRP |
772 S_IWGRP | S_IROTH | S_IWOTH );
773 } else
774 fd = open(filename, O_WRONLY | O_TRUNC);
775 }
776 if (fd < 0)
777 return (errno + 100);
778 file = fdopen(fd, (mode == RRQ)? "r":"w");
779 if (file == NULL) {
780 close(fd);
781 return (errno + 100);
782 }
783 return (0);
784}
785
786static void
787tftp_xmitfile(int peer, const char *mode)
788{
789 uint16_t block;
790 time_t now;
791 struct tftp_stats ts;
792
793 now = time(NULL);
794 if (debug&DEBUG_SIMPLE)
795 tftp_log(LOG_DEBUG, "Transmitting file");
796
797 read_init(0, file, mode);
798 block = 1;
799 tftp_send(peer, &block, &ts);
800 read_close();
801 if (debug&DEBUG_SIMPLE)
| 69#include <stdio.h>
70#include <stdlib.h>
71#include <string.h>
72#include <syslog.h>
73#include <tcpd.h>
74#include <unistd.h>
75
76#include "tftp-file.h"
77#include "tftp-io.h"
78#include "tftp-utils.h"
79#include "tftp-transfer.h"
80#include "tftp-options.h"
81
82static void tftp_wrq(int peer, char *, ssize_t);
83static void tftp_rrq(int peer, char *, ssize_t);
84
85/*
86 * Null-terminated directory prefix list for absolute pathname requests and
87 * search list for relative pathname requests.
88 *
89 * MAXDIRS should be at least as large as the number of arguments that
90 * inetd allows (currently 20).
91 */
92#define MAXDIRS 20
93static struct dirlist {
94 const char *name;
95 int len;
96} dirs[MAXDIRS+1];
97static int suppress_naks;
98static int logging;
99static int ipchroot;
100static int create_new = 0;
101static const char *newfile_format = "%Y%m%d";
102static int increase_name = 0;
103static mode_t mask = S_IWGRP | S_IWOTH;
104
105struct formats;
106static void tftp_recvfile(int peer, const char *mode);
107static void tftp_xmitfile(int peer, const char *mode);
108static int validate_access(int peer, char **, int);
109static char peername[NI_MAXHOST];
110
111static FILE *file;
112
113static struct formats {
114 const char *f_mode;
115 int f_convert;
116} formats[] = {
117 { "netascii", 1 },
118 { "octet", 0 },
119 { NULL, 0 }
120};
121
122int
123main(int argc, char *argv[])
124{
125 struct tftphdr *tp;
126 int peer;
127 socklen_t peerlen, len;
128 ssize_t n;
129 int ch;
130 char *chroot_dir = NULL;
131 struct passwd *nobody;
132 const char *chuser = "nobody";
133 char recvbuffer[MAXPKTSIZE];
134 int allow_ro = 1, allow_wo = 1;
135
136 tzset(); /* syslog in localtime */
137 acting_as_client = 0;
138
139 tftp_openlog("tftpd", LOG_PID | LOG_NDELAY, LOG_FTP);
140 while ((ch = getopt(argc, argv, "cCd:F:lnoOp:s:u:U:wW")) != -1) {
141 switch (ch) {
142 case 'c':
143 ipchroot = 1;
144 break;
145 case 'C':
146 ipchroot = 2;
147 break;
148 case 'd':
149 if (atoi(optarg) != 0)
150 debug += atoi(optarg);
151 else
152 debug |= debug_finds(optarg);
153 break;
154 case 'F':
155 newfile_format = optarg;
156 break;
157 case 'l':
158 logging = 1;
159 break;
160 case 'n':
161 suppress_naks = 1;
162 break;
163 case 'o':
164 options_rfc_enabled = 0;
165 break;
166 case 'O':
167 options_extra_enabled = 0;
168 break;
169 case 'p':
170 packetdroppercentage = atoi(optarg);
171 tftp_log(LOG_INFO,
172 "Randomly dropping %d out of 100 packets",
173 packetdroppercentage);
174 break;
175 case 's':
176 chroot_dir = optarg;
177 break;
178 case 'u':
179 chuser = optarg;
180 break;
181 case 'U':
182 mask = strtol(optarg, NULL, 0);
183 break;
184 case 'w':
185 create_new = 1;
186 break;
187 case 'W':
188 create_new = 1;
189 increase_name = 1;
190 break;
191 default:
192 tftp_log(LOG_WARNING,
193 "ignoring unknown option -%c", ch);
194 }
195 }
196 if (optind < argc) {
197 struct dirlist *dirp;
198
199 /* Get list of directory prefixes. Skip relative pathnames. */
200 for (dirp = dirs; optind < argc && dirp < &dirs[MAXDIRS];
201 optind++) {
202 if (argv[optind][0] == '/') {
203 dirp->name = argv[optind];
204 dirp->len = strlen(dirp->name);
205 dirp++;
206 }
207 }
208 }
209 else if (chroot_dir) {
210 dirs->name = "/";
211 dirs->len = 1;
212 }
213 if (ipchroot > 0 && chroot_dir == NULL) {
214 tftp_log(LOG_ERR, "-c requires -s");
215 exit(1);
216 }
217
218 umask(mask);
219
220 {
221 int on = 1;
222 if (ioctl(0, FIONBIO, &on) < 0) {
223 tftp_log(LOG_ERR, "ioctl(FIONBIO): %s", strerror(errno));
224 exit(1);
225 }
226 }
227
228 /* Find out who we are talking to and what we are going to do */
229 peerlen = sizeof(peer_sock);
230 n = recvfrom(0, recvbuffer, MAXPKTSIZE, 0,
231 (struct sockaddr *)&peer_sock, &peerlen);
232 if (n < 0) {
233 tftp_log(LOG_ERR, "recvfrom: %s", strerror(errno));
234 exit(1);
235 }
236 getnameinfo((struct sockaddr *)&peer_sock, peer_sock.ss_len,
237 peername, sizeof(peername), NULL, 0, NI_NUMERICHOST);
238
239 /*
240 * Now that we have read the message out of the UDP
241 * socket, we fork and exit. Thus, inetd will go back
242 * to listening to the tftp port, and the next request
243 * to come in will start up a new instance of tftpd.
244 *
245 * We do this so that inetd can run tftpd in "wait" mode.
246 * The problem with tftpd running in "nowait" mode is that
247 * inetd may get one or more successful "selects" on the
248 * tftp port before we do our receive, so more than one
249 * instance of tftpd may be started up. Worse, if tftpd
250 * break before doing the above "recvfrom", inetd would
251 * spawn endless instances, clogging the system.
252 */
253 {
254 int i, pid;
255
256 for (i = 1; i < 20; i++) {
257 pid = fork();
258 if (pid < 0) {
259 sleep(i);
260 /*
261 * flush out to most recently sent request.
262 *
263 * This may drop some request, but those
264 * will be resent by the clients when
265 * they timeout. The positive effect of
266 * this flush is to (try to) prevent more
267 * than one tftpd being started up to service
268 * a single request from a single client.
269 */
270 peerlen = sizeof peer_sock;
271 i = recvfrom(0, recvbuffer, MAXPKTSIZE, 0,
272 (struct sockaddr *)&peer_sock, &peerlen);
273 if (i > 0) {
274 n = i;
275 }
276 } else {
277 break;
278 }
279 }
280 if (pid < 0) {
281 tftp_log(LOG_ERR, "fork: %s", strerror(errno));
282 exit(1);
283 } else if (pid != 0) {
284 exit(0);
285 }
286 }
287
288 /*
289 * See if the client is allowed to talk to me.
290 * (This needs to be done before the chroot())
291 */
292 {
293 struct request_info req;
294
295 request_init(&req, RQ_CLIENT_ADDR, peername, 0);
296 request_set(&req, RQ_DAEMON, "tftpd", 0);
297
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");
303
304 /*
305 * Full access might be disabled, but maybe the
306 * client is allowed to do read-only access.
307 */
308 request_set(&req, RQ_DAEMON, "tftpd-ro", 0);
309 allow_ro = hosts_access(&req);
310
311 request_set(&req, RQ_DAEMON, "tftpd-wo", 0);
312 allow_wo = hosts_access(&req);
313
314 if (allow_ro == 0 && allow_wo == 0) {
315 tftp_log(LOG_WARNING,
316 "Unauthorized access from %s", peername);
317 exit(1);
318 }
319
320 if (debug&DEBUG_ACCESS) {
321 if (allow_ro)
322 tftp_log(LOG_WARNING,
323 "But allowed readonly access "
324 "via 'tftpd-ro' entry");
325 if (allow_wo)
326 tftp_log(LOG_WARNING,
327 "But allowed writeonly access "
328 "via 'tftpd-wo' entry");
329 }
330 } else
331 if (debug&DEBUG_ACCESS)
332 tftp_log(LOG_WARNING,
333 "Full access allowed"
334 "in /etc/hosts.allow");
335 }
336
337 /*
338 * Since we exit here, we should do that only after the above
339 * recvfrom to keep inetd from constantly forking should there
340 * be a problem. See the above comment about system clogging.
341 */
342 if (chroot_dir) {
343 if (ipchroot > 0) {
344 char *tempchroot;
345 struct stat sb;
346 int statret;
347 struct sockaddr_storage ss;
348 char hbuf[NI_MAXHOST];
349
350 statret = -1;
351 memcpy(&ss, &peer_sock, peer_sock.ss_len);
352 unmappedaddr((struct sockaddr_in6 *)&ss);
353 getnameinfo((struct sockaddr *)&ss, ss.ss_len,
354 hbuf, sizeof(hbuf), NULL, 0,
355 NI_NUMERICHOST);
356 asprintf(&tempchroot, "%s/%s", chroot_dir, hbuf);
357 if (ipchroot == 2)
358 statret = stat(tempchroot, &sb);
359 if (ipchroot == 1 ||
360 (statret == 0 && (sb.st_mode & S_IFDIR)))
361 chroot_dir = tempchroot;
362 }
363 /* Must get this before chroot because /etc might go away */
364 if ((nobody = getpwnam(chuser)) == NULL) {
365 tftp_log(LOG_ERR, "%s: no such user", chuser);
366 exit(1);
367 }
368 if (chroot(chroot_dir)) {
369 tftp_log(LOG_ERR, "chroot: %s: %s",
370 chroot_dir, strerror(errno));
371 exit(1);
372 }
373 chdir("/");
374 setgroups(1, &nobody->pw_gid);
375 if (setuid(nobody->pw_uid) != 0) {
376 tftp_log(LOG_ERR, "setuid failed");
377 exit(1);
378 }
379 }
380
381 len = sizeof(me_sock);
382 if (getsockname(0, (struct sockaddr *)&me_sock, &len) == 0) {
383 switch (me_sock.ss_family) {
384 case AF_INET:
385 ((struct sockaddr_in *)&me_sock)->sin_port = 0;
386 break;
387 case AF_INET6:
388 ((struct sockaddr_in6 *)&me_sock)->sin6_port = 0;
389 break;
390 default:
391 /* unsupported */
392 break;
393 }
394 } else {
395 memset(&me_sock, 0, sizeof(me_sock));
396 me_sock.ss_family = peer_sock.ss_family;
397 me_sock.ss_len = peer_sock.ss_len;
398 }
399 close(0);
400 close(1);
401 peer = socket(peer_sock.ss_family, SOCK_DGRAM, 0);
402 if (peer < 0) {
403 tftp_log(LOG_ERR, "socket: %s", strerror(errno));
404 exit(1);
405 }
406 if (bind(peer, (struct sockaddr *)&me_sock, me_sock.ss_len) < 0) {
407 tftp_log(LOG_ERR, "bind: %s", strerror(errno));
408 exit(1);
409 }
410
411 tp = (struct tftphdr *)recvbuffer;
412 tp->th_opcode = ntohs(tp->th_opcode);
413 if (tp->th_opcode == RRQ) {
414 if (allow_ro)
415 tftp_rrq(peer, tp->th_stuff, n - 1);
416 else {
417 tftp_log(LOG_WARNING,
418 "%s read access denied", peername);
419 exit(1);
420 }
421 }
422 if (tp->th_opcode == WRQ) {
423 if (allow_wo)
424 tftp_wrq(peer, tp->th_stuff, n - 1);
425 else {
426 tftp_log(LOG_WARNING,
427 "%s write access denied", peername);
428 exit(1);
429 }
430 }
431 exit(1);
432}
433
434static void
435reduce_path(char *fn)
436{
437 char *slash, *ptr;
438
439 /* Reduce all "/+./" to "/" (just in case we've got "/./../" later */
440 while ((slash = strstr(fn, "/./")) != NULL) {
441 for (ptr = slash; ptr > fn && ptr[-1] == '/'; ptr--)
442 ;
443 slash += 2;
444 while (*slash)
445 *++ptr = *++slash;
446 }
447
448 /* Now reduce all "/something/+../" to "/" */
449 while ((slash = strstr(fn, "/../")) != NULL) {
450 if (slash == fn)
451 break;
452 for (ptr = slash; ptr > fn && ptr[-1] == '/'; ptr--)
453 ;
454 for (ptr--; ptr >= fn; ptr--)
455 if (*ptr == '/')
456 break;
457 if (ptr < fn)
458 break;
459 slash += 3;
460 while (*slash)
461 *++ptr = *++slash;
462 }
463}
464
465static char *
466parse_header(int peer, char *recvbuffer, ssize_t size,
467 char **filename, char **mode)
468{
469 char *cp;
470 int i;
471 struct formats *pf;
472
473 *mode = NULL;
474 cp = recvbuffer;
475
476 i = get_field(peer, recvbuffer, size);
477 if (i >= PATH_MAX) {
478 tftp_log(LOG_ERR, "Bad option - filename too long");
479 send_error(peer, EBADOP);
480 exit(1);
481 }
482 *filename = recvbuffer;
483 tftp_log(LOG_INFO, "Filename: '%s'", *filename);
484 cp += i;
485
486 i = get_field(peer, cp, size);
487 *mode = cp;
488 cp += i;
489
490 /* Find the file transfer mode */
491 for (cp = *mode; *cp; cp++)
492 if (isupper(*cp))
493 *cp = tolower(*cp);
494 for (pf = formats; pf->f_mode; pf++)
495 if (strcmp(pf->f_mode, *mode) == 0)
496 break;
497 if (pf->f_mode == NULL) {
498 tftp_log(LOG_ERR,
499 "Bad option - Unknown transfer mode (%s)", *mode);
500 send_error(peer, EBADOP);
501 exit(1);
502 }
503 tftp_log(LOG_INFO, "Mode: '%s'", *mode);
504
505 return (cp + 1);
506}
507
508/*
509 * WRQ - receive a file from the client
510 */
511void
512tftp_wrq(int peer, char *recvbuffer, ssize_t size)
513{
514 char *cp;
515 int has_options = 0, ecode;
516 char *filename, *mode;
517 char fnbuf[PATH_MAX];
518
519 cp = parse_header(peer, recvbuffer, size, &filename, &mode);
520 size -= (cp - recvbuffer) + 1;
521
522 strcpy(fnbuf, filename);
523 reduce_path(fnbuf);
524 filename = fnbuf;
525
526 if (size > 0) {
527 if (options_rfc_enabled)
528 has_options = !parse_options(peer, cp, size);
529 else
530 tftp_log(LOG_INFO, "Options found but not enabled");
531 }
532
533 ecode = validate_access(peer, &filename, WRQ);
534 if (ecode == 0) {
535 if (has_options)
536 send_oack(peer);
537 else
538 send_ack(peer, 0);
539 }
540 if (logging) {
541 tftp_log(LOG_INFO, "%s: write request for %s: %s", peername,
542 filename, errtomsg(ecode));
543 }
544
545 tftp_recvfile(peer, mode);
546 exit(0);
547}
548
549/*
550 * RRQ - send a file to the client
551 */
552void
553tftp_rrq(int peer, char *recvbuffer, ssize_t size)
554{
555 char *cp;
556 int has_options = 0, ecode;
557 char *filename, *mode;
558 char fnbuf[PATH_MAX];
559
560 cp = parse_header(peer, recvbuffer, size, &filename, &mode);
561 size -= (cp - recvbuffer) + 1;
562
563 strcpy(fnbuf, filename);
564 reduce_path(fnbuf);
565 filename = fnbuf;
566
567 if (size > 0) {
568 if (options_rfc_enabled)
569 has_options = !parse_options(peer, cp, size);
570 else
571 tftp_log(LOG_INFO, "Options found but not enabled");
572 }
573
574 ecode = validate_access(peer, &filename, RRQ);
575 if (ecode == 0) {
576 if (has_options) {
577 int n;
578 char lrecvbuffer[MAXPKTSIZE];
579 struct tftphdr *rp = (struct tftphdr *)lrecvbuffer;
580
581 send_oack(peer);
582 n = receive_packet(peer, lrecvbuffer, MAXPKTSIZE,
583 NULL, timeoutpacket);
584 if (n < 0) {
585 if (debug&DEBUG_SIMPLE)
586 tftp_log(LOG_DEBUG, "Aborting: %s",
587 rp_strerror(n));
588 return;
589 }
590 if (rp->th_opcode != ACK) {
591 if (debug&DEBUG_SIMPLE)
592 tftp_log(LOG_DEBUG,
593 "Expected ACK, got %s on OACK",
594 packettype(rp->th_opcode));
595 return;
596 }
597 }
598 }
599
600 if (logging)
601 tftp_log(LOG_INFO, "%s: read request for %s: %s", peername,
602 filename, errtomsg(ecode));
603
604 if (ecode) {
605 /*
606 * Avoid storms of naks to a RRQ broadcast for a relative
607 * bootfile pathname from a diskless Sun.
608 */
609 if (suppress_naks && *filename != '/' && ecode == ENOTFOUND)
610 exit(0);
611 send_error(peer, ecode);
612 exit(1);
613 }
614 tftp_xmitfile(peer, mode);
615}
616
617/*
618 * Find the next value for YYYYMMDD.nn when the file to be written should
619 * be unique. Due to the limitations of nn, we will fail if nn reaches 100.
620 * Besides, that is four updates per hour on a file, which is kind of
621 * execessive anyway.
622 */
623static int
624find_next_name(char *filename, int *fd)
625{
626 int i;
627 time_t tval;
628 size_t len;
629 struct tm lt;
630 char yyyymmdd[MAXPATHLEN];
631 char newname[MAXPATHLEN];
632
633 /* Create the YYYYMMDD part of the filename */
634 time(&tval);
635 lt = *localtime(&tval);
636 len = strftime(yyyymmdd, sizeof(yyyymmdd), newfile_format, <);
637 if (len == 0) {
638 syslog(LOG_WARNING,
639 "Filename suffix too long (%d characters maximum)",
640 MAXPATHLEN);
641 return (EACCESS);
642 }
643
644 /* Make sure the new filename is not too long */
645 if (strlen(filename) > MAXPATHLEN - len - 5) {
646 syslog(LOG_WARNING,
647 "Filename too long (%zd characters, %zd maximum)",
648 strlen(filename), MAXPATHLEN - len - 5);
649 return (EACCESS);
650 }
651
652 /* Find the first file which doesn't exist */
653 for (i = 0; i < 100; i++) {
654 sprintf(newname, "%s.%s.%02d", filename, yyyymmdd, i);
655 *fd = open(newname,
656 O_WRONLY | O_CREAT | O_EXCL,
657 S_IRUSR | S_IWUSR | S_IRGRP |
658 S_IWGRP | S_IROTH | S_IWOTH);
659 if (*fd > 0)
660 return 0;
661 }
662
663 return (EEXIST);
664}
665
666/*
667 * Validate file access. Since we
668 * have no uid or gid, for now require
669 * file to exist and be publicly
670 * readable/writable.
671 * If we were invoked with arguments
672 * from inetd then the file must also be
673 * in one of the given directory prefixes.
674 * Note also, full path name must be
675 * given as we have no login directory.
676 */
677int
678validate_access(int peer, char **filep, int mode)
679{
680 struct stat stbuf;
681 int fd;
682 int error;
683 struct dirlist *dirp;
684 static char pathname[MAXPATHLEN];
685 char *filename = *filep;
686
687 /*
688 * Prevent tricksters from getting around the directory restrictions
689 */
690 if (strstr(filename, "/../"))
691 return (EACCESS);
692
693 if (*filename == '/') {
694 /*
695 * Allow the request if it's in one of the approved locations.
696 * Special case: check the null prefix ("/") by looking
697 * for length = 1 and relying on the arg. processing that
698 * it's a /.
699 */
700 for (dirp = dirs; dirp->name != NULL; dirp++) {
701 if (dirp->len == 1 ||
702 (!strncmp(filename, dirp->name, dirp->len) &&
703 filename[dirp->len] == '/'))
704 break;
705 }
706 /* If directory list is empty, allow access to any file */
707 if (dirp->name == NULL && dirp != dirs)
708 return (EACCESS);
709 if (stat(filename, &stbuf) < 0)
710 return (errno == ENOENT ? ENOTFOUND : EACCESS);
711 if ((stbuf.st_mode & S_IFMT) != S_IFREG)
712 return (ENOTFOUND);
713 if (mode == RRQ) {
714 if ((stbuf.st_mode & S_IROTH) == 0)
715 return (EACCESS);
716 } else {
717 if ((stbuf.st_mode & S_IWOTH) == 0)
718 return (EACCESS);
719 }
720 } else {
721 int err;
722
723 /*
724 * Relative file name: search the approved locations for it.
725 * Don't allow write requests that avoid directory
726 * restrictions.
727 */
728
729 if (!strncmp(filename, "../", 3))
730 return (EACCESS);
731
732 /*
733 * If the file exists in one of the directories and isn't
734 * readable, continue looking. However, change the error code
735 * to give an indication that the file exists.
736 */
737 err = ENOTFOUND;
738 for (dirp = dirs; dirp->name != NULL; dirp++) {
739 snprintf(pathname, sizeof(pathname), "%s/%s",
740 dirp->name, filename);
741 if (stat(pathname, &stbuf) == 0 &&
742 (stbuf.st_mode & S_IFMT) == S_IFREG) {
743 if ((stbuf.st_mode & S_IROTH) != 0) {
744 break;
745 }
746 err = EACCESS;
747 }
748 }
749 if (dirp->name != NULL)
750 *filep = filename = pathname;
751 else if (mode == RRQ)
752 return (err);
753 }
754
755 /*
756 * This option is handled here because it (might) require(s) the
757 * size of the file.
758 */
759 option_tsize(peer, NULL, mode, &stbuf);
760
761 if (mode == RRQ)
762 fd = open(filename, O_RDONLY);
763 else {
764 if (create_new) {
765 if (increase_name) {
766 error = find_next_name(filename, &fd);
767 if (error > 0)
768 return (error + 100);
769 } else
770 fd = open(filename,
771 O_WRONLY | O_TRUNC | O_CREAT,
772 S_IRUSR | S_IWUSR | S_IRGRP |
773 S_IWGRP | S_IROTH | S_IWOTH );
774 } else
775 fd = open(filename, O_WRONLY | O_TRUNC);
776 }
777 if (fd < 0)
778 return (errno + 100);
779 file = fdopen(fd, (mode == RRQ)? "r":"w");
780 if (file == NULL) {
781 close(fd);
782 return (errno + 100);
783 }
784 return (0);
785}
786
787static void
788tftp_xmitfile(int peer, const char *mode)
789{
790 uint16_t block;
791 time_t now;
792 struct tftp_stats ts;
793
794 now = time(NULL);
795 if (debug&DEBUG_SIMPLE)
796 tftp_log(LOG_DEBUG, "Transmitting file");
797
798 read_init(0, file, mode);
799 block = 1;
800 tftp_send(peer, &block, &ts);
801 read_close();
802 if (debug&DEBUG_SIMPLE)
|