| Current Path : /usr/src/libexec/tftpd/ |
FreeBSD hs32.drive.ne.jp 9.1-RELEASE FreeBSD 9.1-RELEASE #1: Wed Jan 14 12:18:08 JST 2015 root@hs32.drive.ne.jp:/sys/amd64/compile/hs32 amd64 |
| Current File : //usr/src/libexec/tftpd/tftpd.c |
/*
* Copyright (c) 1983, 1993
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#ifndef lint
static const char copyright[] =
"@(#) Copyright (c) 1983, 1993\n\
The Regents of the University of California. All rights reserved.\n";
#endif /* not lint */
#ifndef lint
#if 0
static char sccsid[] = "@(#)tftpd.c 8.1 (Berkeley) 6/4/93";
#endif
#endif /* not lint */
#include <sys/cdefs.h>
__FBSDID("$FreeBSD: release/9.1.0/libexec/tftpd/tftpd.c 213102 2010-09-24 14:44:04Z marius $");
/*
* Trivial file transfer protocol server.
*
* This version includes many modifications by Jim Guyton
* <guyton@rand-unix>.
*/
#include <sys/param.h>
#include <sys/ioctl.h>
#include <sys/stat.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/tftp.h>
#include <ctype.h>
#include <errno.h>
#include <fcntl.h>
#include <netdb.h>
#include <pwd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <syslog.h>
#include <tcpd.h>
#include <unistd.h>
#include "tftp-file.h"
#include "tftp-io.h"
#include "tftp-utils.h"
#include "tftp-transfer.h"
#include "tftp-options.h"
static void tftp_wrq(int peer, char *, ssize_t);
static void tftp_rrq(int peer, char *, ssize_t);
/*
* Null-terminated directory prefix list for absolute pathname requests and
* search list for relative pathname requests.
*
* MAXDIRS should be at least as large as the number of arguments that
* inetd allows (currently 20).
*/
#define MAXDIRS 20
static struct dirlist {
const char *name;
int len;
} dirs[MAXDIRS+1];
static int suppress_naks;
static int logging;
static int ipchroot;
static int create_new = 0;
static const char *newfile_format = "%Y%m%d";
static int increase_name = 0;
static mode_t mask = S_IWGRP | S_IWOTH;
struct formats;
static void tftp_recvfile(int peer, const char *mode);
static void tftp_xmitfile(int peer, const char *mode);
static int validate_access(int peer, char **, int);
static char peername[NI_MAXHOST];
FILE *file;
struct formats {
const char *f_mode;
int f_convert;
} formats[] = {
{ "netascii", 1 },
{ "octet", 0 },
{ NULL, 0 }
};
int
main(int argc, char *argv[])
{
struct tftphdr *tp;
int peer;
socklen_t peerlen, len;
ssize_t n;
int ch;
char *chroot_dir = NULL;
struct passwd *nobody;
const char *chuser = "nobody";
char recvbuffer[MAXPKTSIZE];
int allow_ro = 1, allow_wo = 1;
tzset(); /* syslog in localtime */
acting_as_client = 0;
tftp_openlog("tftpd", LOG_PID | LOG_NDELAY, LOG_FTP);
while ((ch = getopt(argc, argv, "cCd:F:lnoOp:s:u:U:wW")) != -1) {
switch (ch) {
case 'c':
ipchroot = 1;
break;
case 'C':
ipchroot = 2;
break;
case 'd':
if (atoi(optarg) != 0)
debug += atoi(optarg);
else
debug |= debug_finds(optarg);
break;
case 'F':
newfile_format = optarg;
break;
case 'l':
logging = 1;
break;
case 'n':
suppress_naks = 1;
break;
case 'o':
options_rfc_enabled = 0;
break;
case 'O':
options_extra_enabled = 0;
break;
case 'p':
packetdroppercentage = atoi(optarg);
tftp_log(LOG_INFO,
"Randomly dropping %d out of 100 packets",
packetdroppercentage);
break;
case 's':
chroot_dir = optarg;
break;
case 'u':
chuser = optarg;
break;
case 'U':
mask = strtol(optarg, NULL, 0);
break;
case 'w':
create_new = 1;
break;
case 'W':
create_new = 1;
increase_name = 1;
break;
default:
tftp_log(LOG_WARNING,
"ignoring unknown option -%c", ch);
}
}
if (optind < argc) {
struct dirlist *dirp;
/* Get list of directory prefixes. Skip relative pathnames. */
for (dirp = dirs; optind < argc && dirp < &dirs[MAXDIRS];
optind++) {
if (argv[optind][0] == '/') {
dirp->name = argv[optind];
dirp->len = strlen(dirp->name);
dirp++;
}
}
}
else if (chroot_dir) {
dirs->name = "/";
dirs->len = 1;
}
if (ipchroot > 0 && chroot_dir == NULL) {
tftp_log(LOG_ERR, "-c requires -s");
exit(1);
}
umask(mask);
{
int on = 1;
if (ioctl(0, FIONBIO, &on) < 0) {
tftp_log(LOG_ERR, "ioctl(FIONBIO): %s", strerror(errno));
exit(1);
}
}
/* Find out who we are talking to and what we are going to do */
peerlen = sizeof(peer_sock);
n = recvfrom(0, recvbuffer, MAXPKTSIZE, 0,
(struct sockaddr *)&peer_sock, &peerlen);
if (n < 0) {
tftp_log(LOG_ERR, "recvfrom: %s", strerror(errno));
exit(1);
}
getnameinfo((struct sockaddr *)&peer_sock, peer_sock.ss_len,
peername, sizeof(peername), NULL, 0, NI_NUMERICHOST);
/*
* Now that we have read the message out of the UDP
* socket, we fork and exit. Thus, inetd will go back
* to listening to the tftp port, and the next request
* to come in will start up a new instance of tftpd.
*
* We do this so that inetd can run tftpd in "wait" mode.
* The problem with tftpd running in "nowait" mode is that
* inetd may get one or more successful "selects" on the
* tftp port before we do our receive, so more than one
* instance of tftpd may be started up. Worse, if tftpd
* break before doing the above "recvfrom", inetd would
* spawn endless instances, clogging the system.
*/
{
int i, pid;
for (i = 1; i < 20; i++) {
pid = fork();
if (pid < 0) {
sleep(i);
/*
* flush out to most recently sent request.
*
* This may drop some request, but those
* will be resent by the clients when
* they timeout. The positive effect of
* this flush is to (try to) prevent more
* than one tftpd being started up to service
* a single request from a single client.
*/
peerlen = sizeof peer_sock;
i = recvfrom(0, recvbuffer, MAXPKTSIZE, 0,
(struct sockaddr *)&peer_sock, &peerlen);
if (i > 0) {
n = i;
}
} else {
break;
}
}
if (pid < 0) {
tftp_log(LOG_ERR, "fork: %s", strerror(errno));
exit(1);
} else if (pid != 0) {
exit(0);
}
}
/*
* See if the client is allowed to talk to me.
* (This needs to be done before the chroot())
*/
{
struct request_info req;
request_init(&req, RQ_CLIENT_ADDR, peername, 0);
request_set(&req, RQ_DAEMON, "tftpd", 0);
if (hosts_access(&req) == 0) {
if (debug&DEBUG_ACCESS)
tftp_log(LOG_WARNING,
"Access denied by 'tftpd' entry "
"in /etc/hosts.allow");
/*
* Full access might be disabled, but maybe the
* client is allowed to do read-only access.
*/
request_set(&req, RQ_DAEMON, "tftpd-ro", 0);
allow_ro = hosts_access(&req);
request_set(&req, RQ_DAEMON, "tftpd-wo", 0);
allow_wo = hosts_access(&req);
if (allow_ro == 0 && allow_wo == 0) {
tftp_log(LOG_WARNING,
"Unauthorized access from %s", peername);
exit(1);
}
if (debug&DEBUG_ACCESS) {
if (allow_ro)
tftp_log(LOG_WARNING,
"But allowed readonly access "
"via 'tftpd-ro' entry");
if (allow_wo)
tftp_log(LOG_WARNING,
"But allowed writeonly access "
"via 'tftpd-wo' entry");
}
} else
if (debug&DEBUG_ACCESS)
tftp_log(LOG_WARNING,
"Full access allowed"
"in /etc/hosts.allow");
}
/*
* Since we exit here, we should do that only after the above
* recvfrom to keep inetd from constantly forking should there
* be a problem. See the above comment about system clogging.
*/
if (chroot_dir) {
if (ipchroot > 0) {
char *tempchroot;
struct stat sb;
int statret;
struct sockaddr_storage ss;
char hbuf[NI_MAXHOST];
statret = -1;
memcpy(&ss, &peer_sock, peer_sock.ss_len);
unmappedaddr((struct sockaddr_in6 *)&ss);
getnameinfo((struct sockaddr *)&ss, ss.ss_len,
hbuf, sizeof(hbuf), NULL, 0,
NI_NUMERICHOST);
asprintf(&tempchroot, "%s/%s", chroot_dir, hbuf);
if (ipchroot == 2)
statret = stat(tempchroot, &sb);
if (ipchroot == 1 ||
(statret == 0 && (sb.st_mode & S_IFDIR)))
chroot_dir = tempchroot;
}
/* Must get this before chroot because /etc might go away */
if ((nobody = getpwnam(chuser)) == NULL) {
tftp_log(LOG_ERR, "%s: no such user", chuser);
exit(1);
}
if (chroot(chroot_dir)) {
tftp_log(LOG_ERR, "chroot: %s: %s",
chroot_dir, strerror(errno));
exit(1);
}
chdir("/");
setgroups(1, &nobody->pw_gid);
setuid(nobody->pw_uid);
}
len = sizeof(me_sock);
if (getsockname(0, (struct sockaddr *)&me_sock, &len) == 0) {
switch (me_sock.ss_family) {
case AF_INET:
((struct sockaddr_in *)&me_sock)->sin_port = 0;
break;
case AF_INET6:
((struct sockaddr_in6 *)&me_sock)->sin6_port = 0;
break;
default:
/* unsupported */
break;
}
} else {
memset(&me_sock, 0, sizeof(me_sock));
me_sock.ss_family = peer_sock.ss_family;
me_sock.ss_len = peer_sock.ss_len;
}
close(0);
close(1);
peer = socket(peer_sock.ss_family, SOCK_DGRAM, 0);
if (peer < 0) {
tftp_log(LOG_ERR, "socket: %s", strerror(errno));
exit(1);
}
if (bind(peer, (struct sockaddr *)&me_sock, me_sock.ss_len) < 0) {
tftp_log(LOG_ERR, "bind: %s", strerror(errno));
exit(1);
}
tp = (struct tftphdr *)recvbuffer;
tp->th_opcode = ntohs(tp->th_opcode);
if (tp->th_opcode == RRQ) {
if (allow_ro)
tftp_rrq(peer, tp->th_stuff, n - 1);
else {
tftp_log(LOG_WARNING,
"%s read access denied", peername);
exit(1);
}
}
if (tp->th_opcode == WRQ) {
if (allow_wo)
tftp_wrq(peer, tp->th_stuff, n - 1);
else {
tftp_log(LOG_WARNING,
"%s write access denied", peername);
exit(1);
}
}
exit(1);
}
static void
reduce_path(char *fn)
{
char *slash, *ptr;
/* Reduce all "/+./" to "/" (just in case we've got "/./../" later */
while ((slash = strstr(fn, "/./")) != NULL) {
for (ptr = slash; ptr > fn && ptr[-1] == '/'; ptr--)
;
slash += 2;
while (*slash)
*++ptr = *++slash;
}
/* Now reduce all "/something/+../" to "/" */
while ((slash = strstr(fn, "/../")) != NULL) {
if (slash == fn)
break;
for (ptr = slash; ptr > fn && ptr[-1] == '/'; ptr--)
;
for (ptr--; ptr >= fn; ptr--)
if (*ptr == '/')
break;
if (ptr < fn)
break;
slash += 3;
while (*slash)
*++ptr = *++slash;
}
}
static char *
parse_header(int peer, char *recvbuffer, ssize_t size,
char **filename, char **mode)
{
char *cp;
int i;
struct formats *pf;
*mode = NULL;
cp = recvbuffer;
i = get_field(peer, recvbuffer, size);
if (i >= PATH_MAX) {
tftp_log(LOG_ERR, "Bad option - filename too long");
send_error(peer, EBADOP);
exit(1);
}
*filename = recvbuffer;
tftp_log(LOG_INFO, "Filename: '%s'", *filename);
cp += i;
i = get_field(peer, cp, size);
*mode = cp;
cp += i;
/* Find the file transfer mode */
for (cp = *mode; *cp; cp++)
if (isupper(*cp))
*cp = tolower(*cp);
for (pf = formats; pf->f_mode; pf++)
if (strcmp(pf->f_mode, *mode) == 0)
break;
if (pf->f_mode == NULL) {
tftp_log(LOG_ERR,
"Bad option - Unknown transfer mode (%s)", *mode);
send_error(peer, EBADOP);
exit(1);
}
tftp_log(LOG_INFO, "Mode: '%s'", *mode);
return (cp + 1);
}
/*
* WRQ - receive a file from the client
*/
void
tftp_wrq(int peer, char *recvbuffer, ssize_t size)
{
char *cp;
int has_options = 0, ecode;
char *filename, *mode;
char fnbuf[PATH_MAX];
cp = parse_header(peer, recvbuffer, size, &filename, &mode);
size -= (cp - recvbuffer) + 1;
strcpy(fnbuf, filename);
reduce_path(fnbuf);
filename = fnbuf;
if (size > 0) {
if (options_rfc_enabled)
has_options = !parse_options(peer, cp, size);
else
tftp_log(LOG_INFO, "Options found but not enabled");
}
ecode = validate_access(peer, &filename, WRQ);
if (ecode == 0) {
if (has_options)
send_oack(peer);
else
send_ack(peer, 0);
}
if (logging) {
tftp_log(LOG_INFO, "%s: write request for %s: %s", peername,
filename, errtomsg(ecode));
}
tftp_recvfile(peer, mode);
exit(0);
}
/*
* RRQ - send a file to the client
*/
void
tftp_rrq(int peer, char *recvbuffer, ssize_t size)
{
char *cp;
int has_options = 0, ecode;
char *filename, *mode;
char fnbuf[PATH_MAX];
cp = parse_header(peer, recvbuffer, size, &filename, &mode);
size -= (cp - recvbuffer) + 1;
strcpy(fnbuf, filename);
reduce_path(fnbuf);
filename = fnbuf;
if (size > 0) {
if (options_rfc_enabled)
has_options = !parse_options(peer, cp, size);
else
tftp_log(LOG_INFO, "Options found but not enabled");
}
ecode = validate_access(peer, &filename, RRQ);
if (ecode == 0) {
if (has_options) {
int n;
char lrecvbuffer[MAXPKTSIZE];
struct tftphdr *rp = (struct tftphdr *)lrecvbuffer;
send_oack(peer);
n = receive_packet(peer, lrecvbuffer, MAXPKTSIZE,
NULL, timeoutpacket);
if (n < 0) {
if (debug&DEBUG_SIMPLE)
tftp_log(LOG_DEBUG, "Aborting: %s",
rp_strerror(n));
return;
}
if (rp->th_opcode != ACK) {
if (debug&DEBUG_SIMPLE)
tftp_log(LOG_DEBUG,
"Expected ACK, got %s on OACK",
packettype(rp->th_opcode));
return;
}
}
}
if (logging)
tftp_log(LOG_INFO, "%s: read request for %s: %s", peername,
filename, errtomsg(ecode));
if (ecode) {
/*
* Avoid storms of naks to a RRQ broadcast for a relative
* bootfile pathname from a diskless Sun.
*/
if (suppress_naks && *filename != '/' && ecode == ENOTFOUND)
exit(0);
send_error(peer, ecode);
exit(1);
}
tftp_xmitfile(peer, mode);
}
/*
* Find the next value for YYYYMMDD.nn when the file to be written should
* be unique. Due to the limitations of nn, we will fail if nn reaches 100.
* Besides, that is four updates per hour on a file, which is kind of
* execessive anyway.
*/
static int
find_next_name(char *filename, int *fd)
{
int i;
time_t tval;
size_t len;
struct tm lt;
char yyyymmdd[MAXPATHLEN];
char newname[MAXPATHLEN];
/* Create the YYYYMMDD part of the filename */
time(&tval);
lt = *localtime(&tval);
len = strftime(yyyymmdd, sizeof(yyyymmdd), newfile_format, <);
if (len == 0) {
syslog(LOG_WARNING,
"Filename suffix too long (%d characters maximum)",
MAXPATHLEN);
return (EACCESS);
}
/* Make sure the new filename is not too long */
if (strlen(filename) > MAXPATHLEN - len - 5) {
syslog(LOG_WARNING,
"Filename too long (%zd characters, %zd maximum)",
strlen(filename), MAXPATHLEN - len - 5);
return (EACCESS);
}
/* Find the first file which doesn't exist */
for (i = 0; i < 100; i++) {
sprintf(newname, "%s.%s.%02d", filename, yyyymmdd, i);
*fd = open(newname,
O_WRONLY | O_CREAT | O_EXCL,
S_IRUSR | S_IWUSR | S_IRGRP |
S_IWGRP | S_IROTH | S_IWOTH);
if (*fd > 0)
return 0;
}
return (EEXIST);
}
/*
* Validate file access. Since we
* have no uid or gid, for now require
* file to exist and be publicly
* readable/writable.
* If we were invoked with arguments
* from inetd then the file must also be
* in one of the given directory prefixes.
* Note also, full path name must be
* given as we have no login directory.
*/
int
validate_access(int peer, char **filep, int mode)
{
struct stat stbuf;
int fd;
int error;
struct dirlist *dirp;
static char pathname[MAXPATHLEN];
char *filename = *filep;
/*
* Prevent tricksters from getting around the directory restrictions
*/
if (strstr(filename, "/../"))
return (EACCESS);
if (*filename == '/') {
/*
* Allow the request if it's in one of the approved locations.
* Special case: check the null prefix ("/") by looking
* for length = 1 and relying on the arg. processing that
* it's a /.
*/
for (dirp = dirs; dirp->name != NULL; dirp++) {
if (dirp->len == 1 ||
(!strncmp(filename, dirp->name, dirp->len) &&
filename[dirp->len] == '/'))
break;
}
/* If directory list is empty, allow access to any file */
if (dirp->name == NULL && dirp != dirs)
return (EACCESS);
if (stat(filename, &stbuf) < 0)
return (errno == ENOENT ? ENOTFOUND : EACCESS);
if ((stbuf.st_mode & S_IFMT) != S_IFREG)
return (ENOTFOUND);
if (mode == RRQ) {
if ((stbuf.st_mode & S_IROTH) == 0)
return (EACCESS);
} else {
if ((stbuf.st_mode & S_IWOTH) == 0)
return (EACCESS);
}
} else {
int err;
/*
* Relative file name: search the approved locations for it.
* Don't allow write requests that avoid directory
* restrictions.
*/
if (!strncmp(filename, "../", 3))
return (EACCESS);
/*
* If the file exists in one of the directories and isn't
* readable, continue looking. However, change the error code
* to give an indication that the file exists.
*/
err = ENOTFOUND;
for (dirp = dirs; dirp->name != NULL; dirp++) {
snprintf(pathname, sizeof(pathname), "%s/%s",
dirp->name, filename);
if (stat(pathname, &stbuf) == 0 &&
(stbuf.st_mode & S_IFMT) == S_IFREG) {
if ((stbuf.st_mode & S_IROTH) != 0) {
break;
}
err = EACCESS;
}
}
if (dirp->name != NULL)
*filep = filename = pathname;
else if (mode == RRQ)
return (err);
}
/*
* This option is handled here because it (might) require(s) the
* size of the file.
*/
option_tsize(peer, NULL, mode, &stbuf);
if (mode == RRQ)
fd = open(filename, O_RDONLY);
else {
if (create_new) {
if (increase_name) {
error = find_next_name(filename, &fd);
if (error > 0)
return (error + 100);
} else
fd = open(filename,
O_WRONLY | O_TRUNC | O_CREAT,
S_IRUSR | S_IWUSR | S_IRGRP |
S_IWGRP | S_IROTH | S_IWOTH );
} else
fd = open(filename, O_WRONLY | O_TRUNC);
}
if (fd < 0)
return (errno + 100);
file = fdopen(fd, (mode == RRQ)? "r":"w");
if (file == NULL) {
close(fd);
return (errno + 100);
}
return (0);
}
static void
tftp_xmitfile(int peer, const char *mode)
{
uint16_t block;
time_t now;
struct tftp_stats ts;
now = time(NULL);
if (debug&DEBUG_SIMPLE)
tftp_log(LOG_DEBUG, "Transmitting file");
read_init(0, file, mode);
block = 1;
tftp_send(peer, &block, &ts);
read_close();
if (debug&DEBUG_SIMPLE)
tftp_log(LOG_INFO, "Sent %d bytes in %d seconds",
ts.amount, time(NULL) - now);
}
static void
tftp_recvfile(int peer, const char *mode)
{
uint16_t block;
struct timeval now1, now2;
struct tftp_stats ts;
gettimeofday(&now1, NULL);
if (debug&DEBUG_SIMPLE)
tftp_log(LOG_DEBUG, "Receiving file");
write_init(0, file, mode);
block = 0;
tftp_receive(peer, &block, &ts, NULL, 0);
write_close();
gettimeofday(&now2, NULL);
if (debug&DEBUG_SIMPLE) {
double f;
if (now1.tv_usec > now2.tv_usec) {
now2.tv_usec += 1000000;
now2.tv_sec--;
}
f = now2.tv_sec - now1.tv_sec +
(now2.tv_usec - now1.tv_usec) / 100000.0;
tftp_log(LOG_INFO,
"Download of %d bytes in %d blocks completed after %0.1f seconds\n",
ts.amount, block, f);
}
return;
}