freebsd-dev/contrib/pf/ftp-proxy/util.c

302 lines
7.7 KiB
C

/* $OpenBSD: util.c,v 1.18 2004/01/22 16:10:30 beck Exp $ */
/*
* Copyright (c) 1996-2001
* Obtuse Systems Corporation. 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. Neither the name of the Obtuse Systems 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 OBTUSE SYSTEMS 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 OBTUSE
* SYSTEMS CORPORATION 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.
*
*/
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <sys/file.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <net/if.h>
#include <net/pfvar.h>
#include <arpa/inet.h>
#include <ctype.h>
#include <errno.h>
#include <netdb.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdarg.h>
#include <sysexits.h>
#include <syslog.h>
#include <unistd.h>
#include "util.h"
int Debug_Level;
int Use_Rdns;
in_addr_t Bind_Addr = INADDR_NONE;
void debuglog(int debug_level, const char *fmt, ...);
void
debuglog(int debug_level, const char *fmt, ...)
{
va_list ap;
va_start(ap, fmt);
if (Debug_Level >= debug_level)
vsyslog(LOG_DEBUG, fmt, ap);
va_end(ap);
}
int
get_proxy_env(int connected_fd, struct sockaddr_in *real_server_sa_ptr,
struct sockaddr_in *client_sa_ptr)
{
struct pfioc_natlook natlook;
socklen_t slen;
int fd;
slen = sizeof(*real_server_sa_ptr);
if (getsockname(connected_fd, (struct sockaddr *)real_server_sa_ptr,
&slen) != 0) {
syslog(LOG_ERR, "getsockname() failed (%m)");
return(-1);
}
slen = sizeof(*client_sa_ptr);
if (getpeername(connected_fd, (struct sockaddr *)client_sa_ptr,
&slen) != 0) {
syslog(LOG_ERR, "getpeername() failed (%m)");
return(-1);
}
/*
* Build up the pf natlook structure.
* Just for IPv4 right now
*/
memset((void *)&natlook, 0, sizeof(natlook));
natlook.af = AF_INET;
natlook.saddr.addr32[0] = client_sa_ptr->sin_addr.s_addr;
natlook.daddr.addr32[0] = real_server_sa_ptr->sin_addr.s_addr;
natlook.proto = IPPROTO_TCP;
natlook.sport = client_sa_ptr->sin_port;
natlook.dport = real_server_sa_ptr->sin_port;
natlook.direction = PF_OUT;
/*
* Open the pf device and lookup the mapping pair to find
* the original address we were supposed to connect to.
*/
fd = open("/dev/pf", O_RDWR);
if (fd == -1) {
syslog(LOG_ERR, "cannot open /dev/pf (%m)");
exit(EX_UNAVAILABLE);
}
if (ioctl(fd, DIOCNATLOOK, &natlook) == -1) {
syslog(LOG_INFO,
"pf nat lookup failed %s:%hu (%m)",
inet_ntoa(client_sa_ptr->sin_addr),
ntohs(client_sa_ptr->sin_port));
close(fd);
return(-1);
}
close(fd);
/*
* Now jam the original address and port back into the into
* destination sockaddr_in for the proxy to deal with.
*/
memset((void *)real_server_sa_ptr, 0, sizeof(struct sockaddr_in));
real_server_sa_ptr->sin_port = natlook.rdport;
real_server_sa_ptr->sin_addr.s_addr = natlook.rdaddr.addr32[0];
real_server_sa_ptr->sin_len = sizeof(struct sockaddr_in);
real_server_sa_ptr->sin_family = AF_INET;
return(0);
}
/*
* Transfer one unit of data across a pair of sockets
*
* A unit of data is as much as we get with a single read(2) call.
*/
int
xfer_data(const char *what_read,int from_fd, int to_fd, struct in_addr from,
struct in_addr to)
{
int rlen, offset, xerrno, mark, flags = 0;
char tbuf[4096];
/*
* Are we at the OOB mark?
*/
if (ioctl(from_fd, SIOCATMARK, &mark) < 0) {
xerrno = errno;
syslog(LOG_ERR, "cannot ioctl(SIOCATMARK) socket from %s (%m)",
what_read);
errno = xerrno;
return(-1);
}
if (mark)
flags = MSG_OOB; /* Yes - at the OOB mark */
snarf:
rlen = recv(from_fd, tbuf, sizeof(tbuf), flags);
if (rlen == -1 && flags == MSG_OOB && errno == EINVAL) {
/* OOB didn't work */
flags = 0;
rlen = recv(from_fd, tbuf, sizeof(tbuf), flags);
}
if (rlen == 0) {
debuglog(3, "EOF on read socket");
return(0);
} else if (rlen == -1) {
if (errno == EAGAIN || errno == EINTR)
goto snarf;
xerrno = errno;
syslog(LOG_ERR, "xfer_data (%s): failed (%m) with flags 0%o",
what_read, flags);
errno = xerrno;
return(-1);
} else {
offset = 0;
debuglog(3, "got %d bytes from socket", rlen);
while (offset < rlen) {
int wlen;
fling:
wlen = send(to_fd, &tbuf[offset], rlen - offset,
flags);
if (wlen == 0) {
debuglog(3, "zero-length write");
goto fling;
} else if (wlen == -1) {
if (errno == EAGAIN || errno == EINTR)
goto fling;
xerrno = errno;
syslog(LOG_INFO, "write failed (%m)");
errno = xerrno;
return(-1);
} else {
debuglog(3, "wrote %d bytes to socket",wlen);
offset += wlen;
}
}
return(offset);
}
}
/*
* get_backchannel_socket gets us a socket bound somewhere in a
* particular range of ports
*/
int
get_backchannel_socket(int type, int min_port, int max_port, int start_port,
int direction, struct sockaddr_in *sap)
{
int count;
/*
* Make sure that direction is 'defined' and that min_port is not
* greater than max_port.
*/
if (direction != -1)
direction = 1;
/* by default we go up by one port until we find one */
if (min_port > max_port) {
errno = EINVAL;
return(-1);
}
count = 1 + max_port - min_port;
/*
* Pick a port we can bind to from within the range we want.
* If the caller specifies -1 as the starting port number then
* we pick one somewhere in the range to try.
* This is an optimization intended to speedup port selection and
* has NOTHING to do with security.
*/
if (start_port == -1)
start_port = (arc4random() % count) + min_port;
if (start_port < min_port || start_port > max_port) {
errno = EINVAL;
return(-1);
}
while (count-- > 0) {
struct sockaddr_in sa;
int one, fd;
fd = socket(AF_INET, type, 0);
bzero(&sa, sizeof sa);
sa.sin_family = AF_INET;
if (Bind_Addr == INADDR_NONE)
if (sap == NULL)
sa.sin_addr.s_addr = INADDR_ANY;
else
sa.sin_addr.s_addr = sap->sin_addr.s_addr;
else
sa.sin_addr.s_addr = Bind_Addr;
/*
* Indicate that we want to reuse a port if it happens that the
* port in question was a listen port recently.
*/
one = 1;
if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &one,
sizeof(one)) == -1)
return(-1);
sa.sin_port = htons(start_port);
if (bind(fd, (struct sockaddr *)&sa, sizeof(sa)) == 0) {
if (sap != NULL)
*sap = sa;
return(fd);
}
if (errno != EADDRINUSE)
return(-1);
/* if it's in use, try the next port */
close(fd);
start_port += direction;
if (start_port < min_port)
start_port = max_port;
else if (start_port > max_port)
start_port = min_port;
}
errno = EAGAIN;
return(-1);
}