Greg Hartman | bd77cf7 | 2015-02-25 13:21:06 -0800 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (c) 2005 Reyk Floeter <reyk@openbsd.org> |
| 3 | * |
| 4 | * Permission to use, copy, modify, and distribute this software for any |
| 5 | * purpose with or without fee is hereby granted, provided that the above |
| 6 | * copyright notice and this permission notice appear in all copies. |
| 7 | * |
| 8 | * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES |
| 9 | * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF |
| 10 | * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR |
| 11 | * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES |
| 12 | * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN |
| 13 | * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF |
| 14 | * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. |
| 15 | */ |
| 16 | |
| 17 | #include "includes.h" |
| 18 | |
| 19 | #include <sys/types.h> |
| 20 | #include <sys/ioctl.h> |
| 21 | |
| 22 | #include <netinet/in.h> |
| 23 | #include <arpa/inet.h> |
| 24 | #include <netinet/ip.h> |
| 25 | |
| 26 | #include <errno.h> |
| 27 | #include <fcntl.h> |
| 28 | #include <stdarg.h> |
| 29 | #include <string.h> |
| 30 | #include <unistd.h> |
| 31 | |
| 32 | #include "openbsd-compat/sys-queue.h" |
| 33 | #include "log.h" |
| 34 | #include "misc.h" |
Adam Langley | d059297 | 2015-03-30 14:49:51 -0700 | [diff] [blame] | 35 | #include "sshbuf.h" |
Greg Hartman | bd77cf7 | 2015-02-25 13:21:06 -0800 | [diff] [blame] | 36 | #include "channels.h" |
Adam Langley | d059297 | 2015-03-30 14:49:51 -0700 | [diff] [blame] | 37 | #include "ssherr.h" |
Greg Hartman | bd77cf7 | 2015-02-25 13:21:06 -0800 | [diff] [blame] | 38 | |
| 39 | /* |
| 40 | * This is the portable version of the SSH tunnel forwarding, it |
| 41 | * uses some preprocessor definitions for various platform-specific |
| 42 | * settings. |
| 43 | * |
| 44 | * SSH_TUN_LINUX Use the (newer) Linux tun/tap device |
| 45 | * SSH_TUN_FREEBSD Use the FreeBSD tun/tap device |
| 46 | * SSH_TUN_COMPAT_AF Translate the OpenBSD address family |
| 47 | * SSH_TUN_PREPEND_AF Prepend/remove the address family |
| 48 | */ |
| 49 | |
| 50 | /* |
| 51 | * System-specific tunnel open function |
| 52 | */ |
| 53 | |
| 54 | #if defined(SSH_TUN_LINUX) |
| 55 | #include <linux/if.h> |
| 56 | #include <linux/if_tun.h> |
| 57 | |
| 58 | int |
| 59 | sys_tun_open(int tun, int mode) |
| 60 | { |
| 61 | struct ifreq ifr; |
| 62 | int fd = -1; |
| 63 | const char *name = NULL; |
| 64 | |
| 65 | if ((fd = open("/dev/net/tun", O_RDWR)) == -1) { |
| 66 | debug("%s: failed to open tunnel control interface: %s", |
| 67 | __func__, strerror(errno)); |
| 68 | return (-1); |
| 69 | } |
| 70 | |
| 71 | bzero(&ifr, sizeof(ifr)); |
| 72 | |
| 73 | if (mode == SSH_TUNMODE_ETHERNET) { |
| 74 | ifr.ifr_flags = IFF_TAP; |
| 75 | name = "tap%d"; |
| 76 | } else { |
| 77 | ifr.ifr_flags = IFF_TUN; |
| 78 | name = "tun%d"; |
| 79 | } |
| 80 | ifr.ifr_flags |= IFF_NO_PI; |
| 81 | |
| 82 | if (tun != SSH_TUNID_ANY) { |
| 83 | if (tun > SSH_TUNID_MAX) { |
| 84 | debug("%s: invalid tunnel id %x: %s", __func__, |
| 85 | tun, strerror(errno)); |
| 86 | goto failed; |
| 87 | } |
| 88 | snprintf(ifr.ifr_name, sizeof(ifr.ifr_name), name, tun); |
| 89 | } |
| 90 | |
| 91 | if (ioctl(fd, TUNSETIFF, &ifr) == -1) { |
| 92 | debug("%s: failed to configure tunnel (mode %d): %s", __func__, |
| 93 | mode, strerror(errno)); |
| 94 | goto failed; |
| 95 | } |
| 96 | |
| 97 | if (tun == SSH_TUNID_ANY) |
| 98 | debug("%s: tunnel mode %d fd %d", __func__, mode, fd); |
| 99 | else |
| 100 | debug("%s: %s mode %d fd %d", __func__, ifr.ifr_name, mode, fd); |
| 101 | |
| 102 | return (fd); |
| 103 | |
| 104 | failed: |
| 105 | close(fd); |
| 106 | return (-1); |
| 107 | } |
| 108 | #endif /* SSH_TUN_LINUX */ |
| 109 | |
| 110 | #ifdef SSH_TUN_FREEBSD |
| 111 | #include <sys/socket.h> |
| 112 | #include <net/if.h> |
| 113 | |
| 114 | #ifdef HAVE_NET_IF_TUN_H |
| 115 | #include <net/if_tun.h> |
| 116 | #endif |
| 117 | |
| 118 | int |
| 119 | sys_tun_open(int tun, int mode) |
| 120 | { |
| 121 | struct ifreq ifr; |
| 122 | char name[100]; |
| 123 | int fd = -1, sock, flag; |
| 124 | const char *tunbase = "tun"; |
| 125 | |
| 126 | if (mode == SSH_TUNMODE_ETHERNET) { |
| 127 | #ifdef SSH_TUN_NO_L2 |
| 128 | debug("%s: no layer 2 tunnelling support", __func__); |
| 129 | return (-1); |
| 130 | #else |
| 131 | tunbase = "tap"; |
| 132 | #endif |
| 133 | } |
| 134 | |
| 135 | /* Open the tunnel device */ |
| 136 | if (tun <= SSH_TUNID_MAX) { |
| 137 | snprintf(name, sizeof(name), "/dev/%s%d", tunbase, tun); |
| 138 | fd = open(name, O_RDWR); |
| 139 | } else if (tun == SSH_TUNID_ANY) { |
| 140 | for (tun = 100; tun >= 0; tun--) { |
| 141 | snprintf(name, sizeof(name), "/dev/%s%d", |
| 142 | tunbase, tun); |
| 143 | if ((fd = open(name, O_RDWR)) >= 0) |
| 144 | break; |
| 145 | } |
| 146 | } else { |
| 147 | debug("%s: invalid tunnel %u\n", __func__, tun); |
| 148 | return (-1); |
| 149 | } |
| 150 | |
| 151 | if (fd < 0) { |
| 152 | debug("%s: %s open failed: %s", __func__, name, |
| 153 | strerror(errno)); |
| 154 | return (-1); |
| 155 | } |
| 156 | |
| 157 | /* Turn on tunnel headers */ |
| 158 | flag = 1; |
| 159 | #if defined(TUNSIFHEAD) && !defined(SSH_TUN_PREPEND_AF) |
| 160 | if (mode != SSH_TUNMODE_ETHERNET && |
| 161 | ioctl(fd, TUNSIFHEAD, &flag) == -1) { |
| 162 | debug("%s: ioctl(%d, TUNSIFHEAD, 1): %s", __func__, fd, |
| 163 | strerror(errno)); |
| 164 | close(fd); |
| 165 | } |
| 166 | #endif |
| 167 | |
| 168 | debug("%s: %s mode %d fd %d", __func__, name, mode, fd); |
| 169 | |
| 170 | /* Set the tunnel device operation mode */ |
| 171 | snprintf(ifr.ifr_name, sizeof(ifr.ifr_name), "%s%d", tunbase, tun); |
| 172 | if ((sock = socket(PF_UNIX, SOCK_STREAM, 0)) == -1) |
| 173 | goto failed; |
| 174 | |
| 175 | if (ioctl(sock, SIOCGIFFLAGS, &ifr) == -1) |
| 176 | goto failed; |
| 177 | if ((ifr.ifr_flags & IFF_UP) == 0) { |
| 178 | ifr.ifr_flags |= IFF_UP; |
| 179 | if (ioctl(sock, SIOCSIFFLAGS, &ifr) == -1) |
| 180 | goto failed; |
| 181 | } |
| 182 | |
| 183 | close(sock); |
| 184 | return (fd); |
| 185 | |
| 186 | failed: |
| 187 | if (fd >= 0) |
| 188 | close(fd); |
| 189 | if (sock >= 0) |
| 190 | close(sock); |
| 191 | debug("%s: failed to set %s mode %d: %s", __func__, name, |
| 192 | mode, strerror(errno)); |
| 193 | return (-1); |
| 194 | } |
| 195 | #endif /* SSH_TUN_FREEBSD */ |
| 196 | |
| 197 | /* |
| 198 | * System-specific channel filters |
| 199 | */ |
| 200 | |
| 201 | #if defined(SSH_TUN_FILTER) |
| 202 | #define OPENBSD_AF_INET 2 |
| 203 | #define OPENBSD_AF_INET6 24 |
| 204 | |
| 205 | int |
| 206 | sys_tun_infilter(struct Channel *c, char *buf, int len) |
| 207 | { |
| 208 | #if defined(SSH_TUN_PREPEND_AF) |
| 209 | char rbuf[CHAN_RBUF]; |
| 210 | struct ip *iph; |
| 211 | #endif |
| 212 | u_int32_t *af; |
| 213 | char *ptr = buf; |
Adam Langley | d059297 | 2015-03-30 14:49:51 -0700 | [diff] [blame] | 214 | int r; |
Greg Hartman | bd77cf7 | 2015-02-25 13:21:06 -0800 | [diff] [blame] | 215 | |
| 216 | #if defined(SSH_TUN_PREPEND_AF) |
| 217 | if (len <= 0 || len > (int)(sizeof(rbuf) - sizeof(*af))) |
| 218 | return (-1); |
| 219 | ptr = (char *)&rbuf[0]; |
| 220 | bcopy(buf, ptr + sizeof(u_int32_t), len); |
| 221 | len += sizeof(u_int32_t); |
| 222 | af = (u_int32_t *)ptr; |
| 223 | |
| 224 | iph = (struct ip *)(ptr + sizeof(u_int32_t)); |
| 225 | switch (iph->ip_v) { |
| 226 | case 6: |
| 227 | *af = AF_INET6; |
| 228 | break; |
| 229 | case 4: |
| 230 | default: |
| 231 | *af = AF_INET; |
| 232 | break; |
| 233 | } |
| 234 | #endif |
| 235 | |
| 236 | #if defined(SSH_TUN_COMPAT_AF) |
| 237 | if (len < (int)sizeof(u_int32_t)) |
| 238 | return (-1); |
| 239 | |
| 240 | af = (u_int32_t *)ptr; |
| 241 | if (*af == htonl(AF_INET6)) |
| 242 | *af = htonl(OPENBSD_AF_INET6); |
| 243 | else |
| 244 | *af = htonl(OPENBSD_AF_INET); |
| 245 | #endif |
| 246 | |
Adam Langley | d059297 | 2015-03-30 14:49:51 -0700 | [diff] [blame] | 247 | if ((r = sshbuf_put_string(&c->input, ptr, len)) != 0) |
| 248 | fatal("%s: buffer error: %s", __func__, ssh_err(r)); |
Greg Hartman | bd77cf7 | 2015-02-25 13:21:06 -0800 | [diff] [blame] | 249 | return (0); |
| 250 | } |
| 251 | |
| 252 | u_char * |
| 253 | sys_tun_outfilter(struct Channel *c, u_char **data, u_int *dlen) |
| 254 | { |
| 255 | u_char *buf; |
| 256 | u_int32_t *af; |
Adam Langley | d059297 | 2015-03-30 14:49:51 -0700 | [diff] [blame] | 257 | int r; |
| 258 | size_t xxx_dlen; |
Greg Hartman | bd77cf7 | 2015-02-25 13:21:06 -0800 | [diff] [blame] | 259 | |
Adam Langley | d059297 | 2015-03-30 14:49:51 -0700 | [diff] [blame] | 260 | /* XXX new API is incompatible with this signature. */ |
| 261 | if ((r = sshbuf_get_string(&c->output, data, &xxx_dlen)) != 0) |
| 262 | fatal("%s: buffer error: %s", __func__, ssh_err(r)); |
| 263 | if (dlen != NULL) |
| 264 | *dlen = xxx_dlen; |
Greg Hartman | bd77cf7 | 2015-02-25 13:21:06 -0800 | [diff] [blame] | 265 | if (*dlen < sizeof(*af)) |
| 266 | return (NULL); |
| 267 | buf = *data; |
| 268 | |
| 269 | #if defined(SSH_TUN_PREPEND_AF) |
| 270 | *dlen -= sizeof(u_int32_t); |
| 271 | buf = *data + sizeof(u_int32_t); |
| 272 | #elif defined(SSH_TUN_COMPAT_AF) |
| 273 | af = ntohl(*(u_int32_t *)buf); |
| 274 | if (*af == OPENBSD_AF_INET6) |
| 275 | *af = htonl(AF_INET6); |
| 276 | else |
| 277 | *af = htonl(AF_INET); |
| 278 | #endif |
| 279 | |
| 280 | return (buf); |
| 281 | } |
| 282 | #endif /* SSH_TUN_FILTER */ |