1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290
|
/*
* Dropbear SSH
*
* Copyright (c) 2002,2003 Matt Johnston
* Copyright (c) 2004 by Mihnea Stoenescu
* All rights reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE. */
#include "includes.h"
#include "ssh.h"
#include "tcpfwd.h"
#include "dbutil.h"
#include "session.h"
#include "buffer.h"
#include "packet.h"
#include "listener.h"
#include "runopts.h"
#ifdef ENABLE_SVR_REMOTETCPFWD
static void send_msg_request_success();
static void send_msg_request_failure();
static int svr_cancelremotetcp();
static int svr_remotetcpreq();
static int newtcpdirect(struct Channel * channel);
const struct ChanType svr_chan_tcpdirect = {
1, /* sepfds */
"direct-tcpip",
newtcpdirect, /* init */
NULL, /* checkclose */
NULL, /* reqhandler */
NULL /* closehandler */
};
static const struct ChanType svr_chan_tcpremote = {
1, /* sepfds */
"forwarded-tcpip",
NULL,
NULL,
NULL,
NULL
};
/* At the moment this is completely used for tcp code (with the name reflecting
* that). If new request types are added, this should be replaced with code
* similar to the request-switching in chansession.c */
void recv_msg_global_request_remotetcp() {
unsigned char* reqname = NULL;
unsigned int namelen;
unsigned int wantreply = 0;
int ret = DROPBEAR_FAILURE;
TRACE(("enter recv_msg_global_request_remotetcp"))
if (svr_opts.noremotetcp) {
TRACE(("leave recv_msg_global_request_remotetcp: remote tcp forwarding disabled"))
goto out;
}
reqname = buf_getstring(ses.payload, &namelen);
wantreply = buf_getbool(ses.payload);
if (namelen > MAX_NAME_LEN) {
TRACE(("name len is wrong: %d", namelen))
goto out;
}
if (strcmp("tcpip-forward", reqname) == 0) {
ret = svr_remotetcpreq();
} else if (strcmp("cancel-tcpip-forward", reqname) == 0) {
ret = svr_cancelremotetcp();
} else {
TRACE(("reqname isn't tcpip-forward: '%s'", reqname))
}
out:
if (wantreply) {
if (ret == DROPBEAR_SUCCESS) {
send_msg_request_success();
} else {
send_msg_request_failure();
}
}
m_free(reqname);
TRACE(("leave recv_msg_global_request"))
}
static void send_msg_request_success() {
CHECKCLEARTOWRITE();
buf_putbyte(ses.writepayload, SSH_MSG_REQUEST_SUCCESS);
encrypt_packet();
}
static void send_msg_request_failure() {
CHECKCLEARTOWRITE();
buf_putbyte(ses.writepayload, SSH_MSG_REQUEST_FAILURE);
encrypt_packet();
}
static int matchtcp(void* typedata1, void* typedata2) {
const struct TCPListener *info1 = (struct TCPListener*)typedata1;
const struct TCPListener *info2 = (struct TCPListener*)typedata2;
return (info1->listenport == info2->listenport)
&& (info1->chantype == info2->chantype)
&& (strcmp(info1->listenaddr, info2->listenaddr) == 0);
}
static int svr_cancelremotetcp() {
int ret = DROPBEAR_FAILURE;
unsigned char * bindaddr = NULL;
unsigned int addrlen;
unsigned int port;
struct Listener * listener = NULL;
struct TCPListener tcpinfo;
TRACE(("enter cancelremotetcp"))
bindaddr = buf_getstring(ses.payload, &addrlen);
if (addrlen > MAX_IP_LEN) {
TRACE(("addr len too long: %d", addrlen))
goto out;
}
port = buf_getint(ses.payload);
tcpinfo.sendaddr = NULL;
tcpinfo.sendport = 0;
tcpinfo.listenaddr = bindaddr;
tcpinfo.listenport = port;
listener = get_listener(CHANNEL_ID_TCPFORWARDED, &tcpinfo, matchtcp);
if (listener) {
remove_listener( listener );
ret = DROPBEAR_SUCCESS;
}
out:
m_free(bindaddr);
TRACE(("leave cancelremotetcp"))
return ret;
}
static int svr_remotetcpreq() {
int ret = DROPBEAR_FAILURE;
unsigned char * bindaddr = NULL;
unsigned int addrlen;
struct TCPListener *tcpinfo = NULL;
unsigned int port;
TRACE(("enter remotetcpreq"))
bindaddr = buf_getstring(ses.payload, &addrlen);
if (addrlen > MAX_IP_LEN) {
TRACE(("addr len too long: %d", addrlen))
goto out;
}
port = buf_getint(ses.payload);
if (port == 0) {
dropbear_log(LOG_INFO, "Server chosen tcpfwd ports are unsupported");
goto out;
}
if (port < 1 || port > 65535) {
TRACE(("invalid port: %d", port))
goto out;
}
if (!ses.allowprivport && port < IPPORT_RESERVED) {
TRACE(("can't assign port < 1024 for non-root"))
goto out;
}
tcpinfo = (struct TCPListener*)m_malloc(sizeof(struct TCPListener));
tcpinfo->sendaddr = NULL;
tcpinfo->sendport = 0;
tcpinfo->listenaddr = bindaddr;
tcpinfo->listenport = port;
tcpinfo->chantype = &svr_chan_tcpremote;
tcpinfo->tcp_type = forwarded;
ret = listen_tcpfwd(tcpinfo);
out:
if (ret == DROPBEAR_FAILURE) {
/* we only free it if a listener wasn't created, since the listener
* has to remember it if it's to be cancelled */
m_free(tcpinfo->listenaddr);
m_free(tcpinfo);
}
TRACE(("leave remotetcpreq"))
return ret;
}
/* Called upon creating a new direct tcp channel (ie we connect out to an
* address */
static int newtcpdirect(struct Channel * channel) {
unsigned char* desthost = NULL;
unsigned int destport;
unsigned char* orighost = NULL;
unsigned int origport;
char portstring[NI_MAXSERV];
int sock;
int len;
int err = SSH_OPEN_ADMINISTRATIVELY_PROHIBITED;
if (svr_opts.nolocaltcp) {
TRACE(("leave newtcpdirect: local tcp forwarding disabled"))
goto out;
}
desthost = buf_getstring(ses.payload, &len);
if (len > MAX_HOST_LEN) {
TRACE(("leave newtcpdirect: desthost too long"))
goto out;
}
destport = buf_getint(ses.payload);
orighost = buf_getstring(ses.payload, &len);
if (len > MAX_HOST_LEN) {
TRACE(("leave newtcpdirect: orighost too long"))
goto out;
}
origport = buf_getint(ses.payload);
/* best be sure */
if (origport > 65535 || destport > 65535) {
TRACE(("leave newtcpdirect: port > 65535"))
goto out;
}
snprintf(portstring, sizeof(portstring), "%d", destport);
sock = connect_remote(desthost, portstring, 1, NULL);
if (sock < 0) {
err = SSH_OPEN_CONNECT_FAILED;
TRACE(("leave newtcpdirect: sock failed"))
goto out;
}
ses.maxfd = MAX(ses.maxfd, sock);
/* We don't set readfd, that will get set after the connection's
* progress succeeds */
channel->writefd = sock;
channel->initconn = 1;
err = SSH_OPEN_IN_PROGRESS;
out:
m_free(desthost);
m_free(orighost);
TRACE(("leave newtcpdirect: err %d", err))
return err;
}
#endif
|