375 lines
8.3 KiB
C
375 lines
8.3 KiB
C
/*
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* Copyright (c) 2005 Reyk Floeter <reyk@openbsd.org>
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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#include "includes.h"
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#include <sys/types.h>
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#include <sys/ioctl.h>
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#include <netinet/in.h>
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#include <arpa/inet.h>
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#include <netinet/ip.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <stdarg.h>
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#include <string.h>
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#include <unistd.h>
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#include "openbsd-compat/sys-queue.h"
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#include "log.h"
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#include "misc.h"
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#include "sshbuf.h"
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#include "channels.h"
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#include "ssherr.h"
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/*
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* This file contains various portability code for network support,
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* including tun/tap forwarding and routing domains.
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*/
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#if defined(SYS_RDOMAIN_LINUX) || defined(SSH_TUN_LINUX)
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#include <linux/if.h>
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#endif
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#if defined(SYS_RDOMAIN_LINUX)
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char *
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sys_get_rdomain(int fd)
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{
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char dev[IFNAMSIZ + 1];
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socklen_t len = sizeof(dev) - 1;
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if (getsockopt(fd, SOL_SOCKET, SO_BINDTODEVICE, dev, &len) == -1) {
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error("%s: cannot determine VRF for fd=%d : %s",
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__func__, fd, strerror(errno));
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return NULL;
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}
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dev[len] = '\0';
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return strdup(dev);
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}
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int
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sys_set_rdomain(int fd, const char *name)
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{
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if (setsockopt(fd, SOL_SOCKET, SO_BINDTODEVICE,
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name, strlen(name)) == -1) {
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error("%s: setsockopt(%d, SO_BINDTODEVICE, %s): %s",
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__func__, fd, name, strerror(errno));
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return -1;
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}
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return 0;
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}
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int
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sys_valid_rdomain(const char *name)
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{
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int fd;
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/*
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* This is a pretty crappy way to test. It would be better to
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* check whether "name" represents a VRF device, but apparently
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* that requires an rtnetlink transaction.
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*/
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if ((fd = socket(AF_INET, SOCK_STREAM, 0)) == -1)
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return 0;
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if (setsockopt(fd, SOL_SOCKET, SO_BINDTODEVICE,
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name, strlen(name)) == -1) {
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close(fd);
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return 0;
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}
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close(fd);
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return 1;
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}
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#elif defined(SYS_RDOMAIN_XXX)
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/* XXX examples */
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char *
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sys_get_rdomain(int fd)
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{
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return NULL;
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}
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int
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sys_set_rdomain(int fd, const char *name)
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{
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return -1;
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}
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int
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valid_rdomain(const char *name)
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{
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return 0;
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}
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void
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sys_set_process_rdomain(const char *name)
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{
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fatal("%s: not supported", __func__);
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}
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#endif /* defined(SYS_RDOMAIN_XXX) */
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/*
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* This is the portable version of the SSH tunnel forwarding, it
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* uses some preprocessor definitions for various platform-specific
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* settings.
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*
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* SSH_TUN_LINUX Use the (newer) Linux tun/tap device
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* SSH_TUN_FREEBSD Use the FreeBSD tun/tap device
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* SSH_TUN_COMPAT_AF Translate the OpenBSD address family
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* SSH_TUN_PREPEND_AF Prepend/remove the address family
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*/
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/*
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* System-specific tunnel open function
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*/
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#if defined(SSH_TUN_LINUX)
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#include <linux/if_tun.h>
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int
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sys_tun_open(int tun, int mode, char **ifname)
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{
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struct ifreq ifr;
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int fd = -1;
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const char *name = NULL;
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if (ifname != NULL)
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*ifname = NULL;
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if ((fd = open("/dev/net/tun", O_RDWR)) == -1) {
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debug("%s: failed to open tunnel control interface: %s",
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__func__, strerror(errno));
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return (-1);
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}
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bzero(&ifr, sizeof(ifr));
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if (mode == SSH_TUNMODE_ETHERNET) {
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ifr.ifr_flags = IFF_TAP;
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name = "tap%d";
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} else {
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ifr.ifr_flags = IFF_TUN;
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name = "tun%d";
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}
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ifr.ifr_flags |= IFF_NO_PI;
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if (tun != SSH_TUNID_ANY) {
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if (tun > SSH_TUNID_MAX) {
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debug("%s: invalid tunnel id %x: %s", __func__,
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tun, strerror(errno));
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goto failed;
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}
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snprintf(ifr.ifr_name, sizeof(ifr.ifr_name), name, tun);
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}
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if (ioctl(fd, TUNSETIFF, &ifr) == -1) {
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debug("%s: failed to configure tunnel (mode %d): %s", __func__,
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mode, strerror(errno));
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goto failed;
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}
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if (tun == SSH_TUNID_ANY)
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debug("%s: tunnel mode %d fd %d", __func__, mode, fd);
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else
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debug("%s: %s mode %d fd %d", __func__, ifr.ifr_name, mode, fd);
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if (ifname != NULL && (*ifname = strdup(ifr.ifr_name)))
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goto failed;
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return (fd);
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failed:
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close(fd);
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return (-1);
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}
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#endif /* SSH_TUN_LINUX */
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#ifdef SSH_TUN_FREEBSD
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#include <sys/socket.h>
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#include <net/if.h>
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#ifdef HAVE_NET_IF_TUN_H
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#include <net/if_tun.h>
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#endif
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int
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sys_tun_open(int tun, int mode, char **ifname)
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{
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struct ifreq ifr;
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char name[100];
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int fd = -1, sock, flag;
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const char *tunbase = "tun";
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if (ifname != NULL)
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*ifname = NULL;
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if (mode == SSH_TUNMODE_ETHERNET) {
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#ifdef SSH_TUN_NO_L2
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debug("%s: no layer 2 tunnelling support", __func__);
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return (-1);
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#else
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tunbase = "tap";
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#endif
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}
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/* Open the tunnel device */
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if (tun <= SSH_TUNID_MAX) {
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snprintf(name, sizeof(name), "/dev/%s%d", tunbase, tun);
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fd = open(name, O_RDWR);
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} else if (tun == SSH_TUNID_ANY) {
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for (tun = 100; tun >= 0; tun--) {
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snprintf(name, sizeof(name), "/dev/%s%d",
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tunbase, tun);
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if ((fd = open(name, O_RDWR)) >= 0)
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break;
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}
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} else {
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debug("%s: invalid tunnel %u\n", __func__, tun);
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return (-1);
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}
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if (fd < 0) {
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debug("%s: %s open failed: %s", __func__, name,
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strerror(errno));
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return (-1);
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}
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/* Turn on tunnel headers */
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flag = 1;
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#if defined(TUNSIFHEAD) && !defined(SSH_TUN_PREPEND_AF)
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if (mode != SSH_TUNMODE_ETHERNET &&
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ioctl(fd, TUNSIFHEAD, &flag) == -1) {
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debug("%s: ioctl(%d, TUNSIFHEAD, 1): %s", __func__, fd,
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strerror(errno));
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close(fd);
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}
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#endif
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debug("%s: %s mode %d fd %d", __func__, name, mode, fd);
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/* Set the tunnel device operation mode */
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snprintf(ifr.ifr_name, sizeof(ifr.ifr_name), "%s%d", tunbase, tun);
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if ((sock = socket(PF_UNIX, SOCK_STREAM, 0)) == -1)
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goto failed;
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if (ioctl(sock, SIOCGIFFLAGS, &ifr) == -1)
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goto failed;
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if ((ifr.ifr_flags & IFF_UP) == 0) {
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ifr.ifr_flags |= IFF_UP;
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if (ioctl(sock, SIOCSIFFLAGS, &ifr) == -1)
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goto failed;
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}
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if (ifname != NULL && (*ifname = strdup(ifr.ifr_name)))
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goto failed;
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close(sock);
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return (fd);
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failed:
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if (fd >= 0)
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close(fd);
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if (sock >= 0)
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close(sock);
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debug("%s: failed to set %s mode %d: %s", __func__, name,
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mode, strerror(errno));
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return (-1);
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}
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#endif /* SSH_TUN_FREEBSD */
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/*
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* System-specific channel filters
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*/
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#if defined(SSH_TUN_FILTER)
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/*
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* The tunnel forwarding protocol prepends the address family of forwarded
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* IP packets using OpenBSD's numbers.
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*/
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#define OPENBSD_AF_INET 2
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#define OPENBSD_AF_INET6 24
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int
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sys_tun_infilter(struct ssh *ssh, struct Channel *c, char *buf, int _len)
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{
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int r;
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size_t len;
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char *ptr = buf;
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#if defined(SSH_TUN_PREPEND_AF)
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char rbuf[CHAN_RBUF];
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struct ip iph;
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#endif
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#if defined(SSH_TUN_PREPEND_AF) || defined(SSH_TUN_COMPAT_AF)
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u_int32_t af;
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#endif
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/* XXX update channel input filter API to use unsigned length */
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if (_len < 0)
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return -1;
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len = _len;
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#if defined(SSH_TUN_PREPEND_AF)
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if (len <= sizeof(iph) || len > sizeof(rbuf) - 4)
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return -1;
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/* Determine address family from packet IP header. */
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memcpy(&iph, buf, sizeof(iph));
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af = iph.ip_v == 6 ? OPENBSD_AF_INET6 : OPENBSD_AF_INET;
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/* Prepend address family to packet using OpenBSD constants */
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memcpy(rbuf + 4, buf, len);
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len += 4;
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POKE_U32(rbuf, af);
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ptr = rbuf;
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#elif defined(SSH_TUN_COMPAT_AF)
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/* Convert existing address family header to OpenBSD value */
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if (len <= 4)
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return -1;
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af = PEEK_U32(buf);
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/* Put it back */
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POKE_U32(buf, af == AF_INET6 ? OPENBSD_AF_INET6 : OPENBSD_AF_INET);
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#endif
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if ((r = sshbuf_put_string(c->input, ptr, len)) != 0)
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fatal("%s: buffer error: %s", __func__, ssh_err(r));
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return (0);
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}
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u_char *
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sys_tun_outfilter(struct ssh *ssh, struct Channel *c,
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u_char **data, size_t *dlen)
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{
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u_char *buf;
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u_int32_t af;
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int r;
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/* XXX new API is incompatible with this signature. */
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if ((r = sshbuf_get_string(c->output, data, dlen)) != 0)
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fatal("%s: buffer error: %s", __func__, ssh_err(r));
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if (*dlen < sizeof(af))
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return (NULL);
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buf = *data;
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#if defined(SSH_TUN_PREPEND_AF)
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/* skip address family */
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*dlen -= sizeof(af);
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buf = *data + sizeof(af);
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#elif defined(SSH_TUN_COMPAT_AF)
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/* translate address family */
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af = (PEEK_U32(buf) == OPENBSD_AF_INET6) ? AF_INET6 : AF_INET;
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POKE_U32(buf, af);
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#endif
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return (buf);
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}
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#endif /* SSH_TUN_FILTER */
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