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. All advertising materials mentioning features or use of this software
14 * must display the following acknowledgement:
15 * This product includes software developed by the University of
16 * California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 * may be used to endorse or promote products derived from this software
19 * without specific prior written permission.
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
35 static const char copyright[] =
36 "@(#) Copyright (c) 1983, 1993\n\
37 The Regents of the University of California. All rights reserved.\n";
42 static char sccsid[] = "@(#)tftpd.c 8.1 (Berkeley) 6/4/93";
44 static const char rcsid[] =
45 "$FreeBSD: src/libexec/tftpd/tftpd.c,v 1.15.2.5 2003/04/06 19:42:56 dwmalone Exp $";
49 * Trivial file transfer protocol server.
51 * This version includes many modifications by Jim Guyton
55 #include <sys/param.h>
56 #include <sys/ioctl.h>
58 #include <sys/socket.h>
59 #include <sys/types.h>
61 #include <netinet/in.h>
62 #include <arpa/tftp.h>
63 #include <arpa/inet.h>
82 #define MAX_TIMEOUTS 5
85 int rexmtval = TIMEOUT;
86 int max_rexmtval = 2*TIMEOUT;
88 #define PKTSIZE SEGSIZE+4
91 struct sockaddr_storage from;
94 void tftp(struct tftphdr *, int);
95 static void unmappedaddr(struct sockaddr_in6 *);
98 * Null-terminated directory prefix list for absolute pathname requests and
99 * search list for relative pathname requests.
101 * MAXDIRS should be at least as large as the number of arguments that
102 * inetd allows (currently 20).
105 static struct dirlist {
109 static int suppress_naks;
113 static const char *errtomsg(int);
114 static void nak(int);
115 static void oack(void);
117 static void timer(int);
118 static void justquit(int);
121 main(int argc, char *argv[])
126 struct sockaddr_storage me;
128 char *chroot_dir = NULL;
129 struct passwd *nobody;
130 const char *chuser = "nobody";
132 openlog("tftpd", LOG_PID | LOG_NDELAY, LOG_FTP);
133 while ((ch = getopt(argc, argv, "cClns:u:")) != -1) {
154 syslog(LOG_WARNING, "ignoring unknown option -%c", ch);
158 struct dirlist *dirp;
160 /* Get list of directory prefixes. Skip relative pathnames. */
161 for (dirp = dirs; optind < argc && dirp < &dirs[MAXDIRS];
163 if (argv[optind][0] == '/') {
164 dirp->name = argv[optind];
165 dirp->len = strlen(dirp->name);
170 else if (chroot_dir) {
174 if (ipchroot && chroot_dir == NULL) {
175 syslog(LOG_ERR, "-c requires -s");
180 if (ioctl(0, FIONBIO, &on) < 0) {
181 syslog(LOG_ERR, "ioctl(FIONBIO): %m");
184 fromlen = sizeof (from);
185 n = recvfrom(0, buf, sizeof (buf), 0,
186 (struct sockaddr *)&from, &fromlen);
188 syslog(LOG_ERR, "recvfrom: %m");
192 * Now that we have read the message out of the UDP
193 * socket, we fork and exit. Thus, inetd will go back
194 * to listening to the tftp port, and the next request
195 * to come in will start up a new instance of tftpd.
197 * We do this so that inetd can run tftpd in "wait" mode.
198 * The problem with tftpd running in "nowait" mode is that
199 * inetd may get one or more successful "selects" on the
200 * tftp port before we do our receive, so more than one
201 * instance of tftpd may be started up. Worse, if tftpd
202 * break before doing the above "recvfrom", inetd would
203 * spawn endless instances, clogging the system.
209 for (i = 1; i < 20; i++) {
214 * flush out to most recently sent request.
216 * This may drop some request, but those
217 * will be resent by the clients when
218 * they timeout. The positive effect of
219 * this flush is to (try to) prevent more
220 * than one tftpd being started up to service
221 * a single request from a single client.
224 i = recvfrom(0, buf, sizeof (buf), 0,
225 (struct sockaddr *)&from, &j);
235 syslog(LOG_ERR, "fork: %m");
237 } else if (pid != 0) {
243 * Since we exit here, we should do that only after the above
244 * recvfrom to keep inetd from constantly forking should there
245 * be a problem. See the above comment about system clogging.
252 struct sockaddr_storage ss;
253 char hbuf[NI_MAXHOST];
255 memcpy(&ss, &from, from.ss_len);
256 unmappedaddr((struct sockaddr_in6 *)&ss);
257 getnameinfo((struct sockaddr *)&ss, ss.ss_len,
258 hbuf, sizeof(hbuf), NULL, 0,
259 NI_NUMERICHOST | NI_WITHSCOPEID);
260 asprintf(&tempchroot, "%s/%s", chroot_dir, hbuf);
261 statret = stat(tempchroot, &sb);
262 if ((sb.st_mode & S_IFDIR) &&
263 (statret == 0 || (statret == -1 && ipchroot == 1)))
264 chroot_dir = tempchroot;
266 /* Must get this before chroot because /etc might go away */
267 if ((nobody = getpwnam(chuser)) == NULL) {
268 syslog(LOG_ERR, "%s: no such user", chuser);
271 if (chroot(chroot_dir)) {
272 syslog(LOG_ERR, "chroot: %s: %m", chroot_dir);
276 setuid(nobody->pw_uid);
277 setgroups(1, &nobody->pw_gid);
281 if (getsockname(0, (struct sockaddr *)&me, &len) == 0) {
282 switch (me.ss_family) {
284 ((struct sockaddr_in *)&me)->sin_port = 0;
287 ((struct sockaddr_in6 *)&me)->sin6_port = 0;
294 memset(&me, 0, sizeof(me));
295 me.ss_family = from.ss_family;
296 me.ss_len = from.ss_len;
301 peer = socket(from.ss_family, SOCK_DGRAM, 0);
303 syslog(LOG_ERR, "socket: %m");
306 if (bind(peer, (struct sockaddr *)&me, me.ss_len) < 0) {
307 syslog(LOG_ERR, "bind: %m");
310 if (connect(peer, (struct sockaddr *)&from, from.ss_len) < 0) {
311 syslog(LOG_ERR, "connect: %m");
314 tp = (struct tftphdr *)buf;
315 tp->th_opcode = ntohs(tp->th_opcode);
316 if (tp->th_opcode == RRQ || tp->th_opcode == WRQ)
322 int validate_access(char **, int);
323 void xmitfile(struct formats *);
324 void recvfile(struct formats *);
328 int (*f_validate)(char **, int);
329 void (*f_send)(struct formats *);
330 void (*f_recv)(struct formats *);
333 { "netascii", validate_access, xmitfile, recvfile, 1 },
334 { "octet", validate_access, xmitfile, recvfile, 0 },
336 { "mail", validate_user, sendmail, recvmail, 1 },
338 { 0, NULL, NULL, NULL, 0 }
344 int o_reply; /* turn into union if need be */
346 { "tsize", NULL, 0 }, /* OPT_TSIZE */
347 { "timeout", NULL, 0 }, /* OPT_TIMEOUT */
357 * Handle initial connection protocol.
360 tftp(struct tftphdr *tp, int size)
363 int i, first = 1, has_options = 0, ecode;
365 char *filename, *mode, *option, *ccp;
367 filename = cp = tp->th_stuff;
369 while (cp < buf + size) {
383 for (cp = mode; *cp; cp++)
386 for (pf = formats; pf->f_mode; pf++)
387 if (strcmp(pf->f_mode, mode) == 0)
389 if (pf->f_mode == 0) {
393 while (++cp < buf + size) {
394 for (i = 2, ccp = cp; i > 0; ccp++) {
395 if (ccp >= buf + size) {
397 * Don't reject the request, just stop trying
398 * to parse the option and get on with it.
399 * Some Apple OpenFirmware versions have
400 * trailing garbage on the end of otherwise
404 } else if (*ccp == '\0')
407 for (option = cp; *cp; cp++)
410 for (i = 0; options[i].o_type != NULL; i++)
411 if (strcmp(option, options[i].o_type) == 0) {
412 options[i].o_request = ++cp;
419 if (options[OPT_TIMEOUT].o_request) {
420 int to = atoi(options[OPT_TIMEOUT].o_request);
421 if (to < 1 || to > 255) {
425 else if (to <= max_rexmtval)
426 options[OPT_TIMEOUT].o_reply = rexmtval = to;
428 options[OPT_TIMEOUT].o_request = NULL;
431 ecode = (*pf->f_validate)(&filename, tp->th_opcode);
435 char hbuf[NI_MAXHOST];
437 getnameinfo((struct sockaddr *)&from, from.ss_len,
438 hbuf, sizeof(hbuf), NULL, 0,
440 syslog(LOG_INFO, "%s: %s request for %s: %s", hbuf,
441 tp->th_opcode == WRQ ? "write" : "read",
442 filename, errtomsg(ecode));
446 * Avoid storms of naks to a RRQ broadcast for a relative
447 * bootfile pathname from a diskless Sun.
449 if (suppress_naks && *filename != '/' && ecode == ENOTFOUND)
454 if (tp->th_opcode == WRQ)
465 * Validate file access. Since we
466 * have no uid or gid, for now require
467 * file to exist and be publicly
469 * If we were invoked with arguments
470 * from inetd then the file must also be
471 * in one of the given directory prefixes.
472 * Note also, full path name must be
473 * given as we have no login directory.
476 validate_access(char **filep, int mode)
480 struct dirlist *dirp;
481 static char pathname[MAXPATHLEN];
482 char *filename = *filep;
485 * Prevent tricksters from getting around the directory restrictions
487 if (strstr(filename, "/../"))
490 if (*filename == '/') {
492 * Allow the request if it's in one of the approved locations.
493 * Special case: check the null prefix ("/") by looking
494 * for length = 1 and relying on the arg. processing that
497 for (dirp = dirs; dirp->name != NULL; dirp++) {
498 if (dirp->len == 1 ||
499 (!strncmp(filename, dirp->name, dirp->len) &&
500 filename[dirp->len] == '/'))
503 /* If directory list is empty, allow access to any file */
504 if (dirp->name == NULL && dirp != dirs)
506 if (stat(filename, &stbuf) < 0)
507 return (errno == ENOENT ? ENOTFOUND : EACCESS);
508 if ((stbuf.st_mode & S_IFMT) != S_IFREG)
511 if ((stbuf.st_mode & S_IROTH) == 0)
514 if ((stbuf.st_mode & S_IWOTH) == 0)
521 * Relative file name: search the approved locations for it.
522 * Don't allow write requests that avoid directory
526 if (!strncmp(filename, "../", 3))
530 * If the file exists in one of the directories and isn't
531 * readable, continue looking. However, change the error code
532 * to give an indication that the file exists.
535 for (dirp = dirs; dirp->name != NULL; dirp++) {
536 snprintf(pathname, sizeof(pathname), "%s/%s",
537 dirp->name, filename);
538 if (stat(pathname, &stbuf) == 0 &&
539 (stbuf.st_mode & S_IFMT) == S_IFREG) {
540 if ((stbuf.st_mode & S_IROTH) != 0) {
546 if (dirp->name == NULL)
548 *filep = filename = pathname;
550 if (options[OPT_TSIZE].o_request) {
552 options[OPT_TSIZE].o_reply = stbuf.st_size;
554 /* XXX Allows writes of all sizes. */
555 options[OPT_TSIZE].o_reply =
556 atoi(options[OPT_TSIZE].o_request);
558 fd = open(filename, mode == RRQ ? O_RDONLY : O_WRONLY|O_TRUNC);
560 return (errno + 100);
561 file = fdopen(fd, (mode == RRQ)? "r":"w");
572 timer(int sig __unused)
574 if (++timeouts > MAX_TIMEOUTS)
576 longjmp(timeoutbuf, 1);
580 * Send the requested file.
583 xmitfile(struct formats *pf)
586 struct tftphdr *ap; /* ack packet */
588 volatile unsigned short block;
590 signal(SIGALRM, timer);
592 ap = (struct tftphdr *)ackbuf;
595 size = readit(file, &dp, pf->f_convert);
600 dp->th_opcode = htons((u_short)DATA);
601 dp->th_block = htons((u_short)block);
603 (void)setjmp(timeoutbuf);
609 if (send(peer, dp, size + 4, 0) != size + 4) {
611 t = (t < 32) ? t<< 1 : t;
613 syslog(LOG_ERR, "write: %m");
620 read_ahead(file, pf->f_convert);
622 alarm(rexmtval); /* read the ack */
623 n = recv(peer, ackbuf, sizeof (ackbuf), 0);
626 syslog(LOG_ERR, "read: %m");
629 ap->th_opcode = ntohs((u_short)ap->th_opcode);
630 ap->th_block = ntohs((u_short)ap->th_block);
632 if (ap->th_opcode == ERROR)
635 if (ap->th_opcode == ACK) {
636 if (ap->th_block == block)
638 /* Re-synchronize with the other side */
639 (void) synchnet(peer);
640 if (ap->th_block == (block -1))
646 } while (size == SEGSIZE);
652 justquit(int sig __unused)
662 recvfile(struct formats *pf)
665 struct tftphdr *ap; /* ack buffer */
667 volatile unsigned short block;
669 signal(SIGALRM, timer);
671 ap = (struct tftphdr *)ackbuf;
675 ap->th_opcode = htons((u_short)ACK);
676 ap->th_block = htons((u_short)block);
678 (void) setjmp(timeoutbuf);
680 if (send(peer, ackbuf, 4, 0) != 4) {
681 syslog(LOG_ERR, "write: %m");
684 write_behind(file, pf->f_convert);
687 n = recv(peer, dp, PKTSIZE, 0);
689 if (n < 0) { /* really? */
690 syslog(LOG_ERR, "read: %m");
693 dp->th_opcode = ntohs((u_short)dp->th_opcode);
694 dp->th_block = ntohs((u_short)dp->th_block);
695 if (dp->th_opcode == ERROR)
697 if (dp->th_opcode == DATA) {
698 if (dp->th_block == block) {
701 /* Re-synchronize with the other side */
702 (void) synchnet(peer);
703 if (dp->th_block == (block-1))
704 goto send_ack; /* rexmit */
707 /* size = write(file, dp->th_data, n - 4); */
708 size = writeit(file, &dp, n - 4, pf->f_convert);
709 if (size != (n-4)) { /* ahem */
710 if (size < 0) nak(errno + 100);
714 } while (size == SEGSIZE);
715 write_behind(file, pf->f_convert);
716 (void) fclose(file); /* close data file */
718 ap->th_opcode = htons((u_short)ACK); /* send the "final" ack */
719 ap->th_block = htons((u_short)(block));
720 (void) send(peer, ackbuf, 4, 0);
722 signal(SIGALRM, justquit); /* just quit on timeout */
724 n = recv(peer, buf, sizeof (buf), 0); /* normally times out and quits */
726 if (n >= 4 && /* if read some data */
727 dp->th_opcode == DATA && /* and got a data block */
728 block == dp->th_block) { /* then my last ack was lost */
729 (void) send(peer, ackbuf, 4, 0); /* resend final ack */
739 { EUNDEF, "Undefined error code" },
740 { ENOTFOUND, "File not found" },
741 { EACCESS, "Access violation" },
742 { ENOSPACE, "Disk full or allocation exceeded" },
743 { EBADOP, "Illegal TFTP operation" },
744 { EBADID, "Unknown transfer ID" },
745 { EEXISTS, "File already exists" },
746 { ENOUSER, "No such user" },
747 { EOPTNEG, "Option negotiation" },
754 static char ebuf[20];
758 for (pe = errmsgs; pe->e_code >= 0; pe++)
759 if (pe->e_code == error)
761 snprintf(ebuf, sizeof(buf), "error %d", error);
766 * Send a nak packet (error message).
767 * Error code passed in is one of the
768 * standard TFTP codes, or a UNIX errno
778 tp = (struct tftphdr *)buf;
779 tp->th_opcode = htons((u_short)ERROR);
780 tp->th_code = htons((u_short)error);
781 for (pe = errmsgs; pe->e_code >= 0; pe++)
782 if (pe->e_code == error)
784 if (pe->e_code < 0) {
785 pe->e_msg = strerror(error - 100);
786 tp->th_code = EUNDEF; /* set 'undef' errorcode */
788 strcpy(tp->th_msg, pe->e_msg);
789 length = strlen(pe->e_msg);
790 tp->th_msg[length] = '\0';
792 if (send(peer, buf, length, 0) != length)
793 syslog(LOG_ERR, "nak: %m");
796 /* translate IPv4 mapped IPv6 address to IPv4 address */
798 unmappedaddr(struct sockaddr_in6 *sin6)
800 struct sockaddr_in *sin4;
804 if (sin6->sin6_family != AF_INET6 ||
805 !IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr))
807 sin4 = (struct sockaddr_in *)sin6;
808 addr = *(u_int32_t *)&sin6->sin6_addr.s6_addr[12];
809 port = sin6->sin6_port;
810 memset(sin4, 0, sizeof(struct sockaddr_in));
811 sin4->sin_addr.s_addr = addr;
812 sin4->sin_port = port;
813 sin4->sin_family = AF_INET;
814 sin4->sin_len = sizeof(struct sockaddr_in);
818 * Send an oack packet (option acknowledgement).
823 struct tftphdr *tp, *ap;
827 tp = (struct tftphdr *)buf;
829 size = sizeof(buf) - 2;
830 tp->th_opcode = htons((u_short)OACK);
831 for (i = 0; options[i].o_type != NULL; i++) {
832 if (options[i].o_request) {
833 n = snprintf(bp, size, "%s%c%d", options[i].o_type,
834 0, options[i].o_reply);
838 syslog(LOG_ERR, "oack: buffer overflow");
844 ap = (struct tftphdr *)ackbuf;
845 signal(SIGALRM, timer);
848 (void)setjmp(timeoutbuf);
849 if (send(peer, buf, size, 0) != size) {
850 syslog(LOG_INFO, "oack: %m");
856 n = recv(peer, ackbuf, sizeof (ackbuf), 0);
859 syslog(LOG_ERR, "recv: %m");
862 ap->th_opcode = ntohs((u_short)ap->th_opcode);
863 ap->th_block = ntohs((u_short)ap->th_block);
864 if (ap->th_opcode == ERROR)
866 if (ap->th_opcode == ACK && ap->th_block == 0)