1/*
2 * Dropbear SSH
3 *
4 * Copyright (c) 2002,2003 Matt Johnston
5 * All rights reserved.
6 *
7 * Permission is hereby granted, free of charge, to any person obtaining a copy
8 * of this software and associated documentation files (the "Software"), to deal
9 * in the Software without restriction, including without limitation the rights
10 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
11 * copies of the Software, and to permit persons to whom the Software is
12 * furnished to do so, subject to the following conditions:
13 *
14 * The above copyright notice and this permission notice shall be included in
15 * all copies or substantial portions of the Software.
16 *
17 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
18 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
19 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
20 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
21 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
22 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
23 * SOFTWARE. */
24
25#include "includes.h"
26#include "ssh.h"
27#include "tcpfwd.h"
28#include "dbutil.h"
29#include "session.h"
30#include "buffer.h"
31#include "packet.h"
32#include "listener.h"
33#include "runopts.h"
34
35#ifdef DROPBEAR_TCP_ACCEPT
36
37static void cleanup_tcp(struct Listener *listener) {
38
39	struct TCPListener *tcpinfo = (struct TCPListener*)(listener->typedata);
40
41	m_free(tcpinfo->sendaddr);
42	m_free(tcpinfo->listenaddr);
43	m_free(tcpinfo);
44}
45
46static void tcp_acceptor(struct Listener *listener, int sock) {
47
48	int fd;
49	struct sockaddr_storage addr;
50	socklen_t len;
51	char ipstring[NI_MAXHOST], portstring[NI_MAXSERV];
52	struct TCPListener *tcpinfo = (struct TCPListener*)(listener->typedata);
53
54	len = sizeof(addr);
55
56	fd = accept(sock, (struct sockaddr*)&addr, &len);
57	if (fd < 0) {
58		return;
59	}
60
61	if (getnameinfo((struct sockaddr*)&addr, len, ipstring, sizeof(ipstring),
62				portstring, sizeof(portstring),
63				NI_NUMERICHOST | NI_NUMERICSERV) != 0) {
64		return;
65	}
66
67	if (send_msg_channel_open_init(fd, tcpinfo->chantype) == DROPBEAR_SUCCESS) {
68		unsigned char* addr = NULL;
69		unsigned int port = 0;
70
71		if (tcpinfo->tcp_type == direct) {
72			/* "direct-tcpip" */
73			/* host to connect, port to connect */
74			addr = tcpinfo->sendaddr;
75			port = tcpinfo->sendport;
76		} else {
77			dropbear_assert(tcpinfo->tcp_type == forwarded);
78			/* "forwarded-tcpip" */
79			/* address that was connected, port that was connected */
80			addr = tcpinfo->listenaddr;
81			port = tcpinfo->listenport;
82		}
83
84		buf_putstring(ses.writepayload, addr, strlen(addr));
85		buf_putint(ses.writepayload, port);
86
87		/* originator ip */
88		buf_putstring(ses.writepayload, ipstring, strlen(ipstring));
89		/* originator port */
90		buf_putint(ses.writepayload, atol(portstring));
91
92		encrypt_packet();
93
94	} else {
95		/* XXX debug? */
96		close(fd);
97	}
98}
99
100int listen_tcpfwd(struct TCPListener* tcpinfo) {
101
102	char portstring[NI_MAXSERV];
103	int socks[DROPBEAR_MAX_SOCKS];
104	struct Listener *listener = NULL;
105	int nsocks;
106	char* errstring = NULL;
107	/* listen_spec = NULL indicates localhost */
108	const char* listen_spec = NULL;
109
110	TRACE(("enter listen_tcpfwd"))
111
112	/* first we try to bind, so don't need to do so much cleanup on failure */
113	snprintf(portstring, sizeof(portstring), "%d", tcpinfo->listenport);
114
115	/* a listenaddr of "" will indicate all interfaces */
116	if (opts.listen_fwd_all
117			&& (strcmp(tcpinfo->listenaddr, "localhost") != 0) ) {
118		listen_spec = tcpinfo->listenaddr;
119	}
120
121	nsocks = dropbear_listen(listen_spec, portstring, socks,
122			DROPBEAR_MAX_SOCKS, &errstring, &ses.maxfd);
123	if (nsocks < 0) {
124		dropbear_log(LOG_INFO, "TCP forward failed: %s", errstring);
125		m_free(errstring);
126		TRACE(("leave listen_tcpfwd: dropbear_listen failed"))
127		return DROPBEAR_FAILURE;
128	}
129	m_free(errstring);
130
131	/* new_listener will close the socks if it fails */
132	listener = new_listener(socks, nsocks, CHANNEL_ID_TCPFORWARDED, tcpinfo,
133			tcp_acceptor, cleanup_tcp);
134
135	if (listener == NULL) {
136		TRACE(("leave listen_tcpfwd: listener failed"))
137		return DROPBEAR_FAILURE;
138	}
139
140	TRACE(("leave listen_tcpfwd: success"))
141	return DROPBEAR_SUCCESS;
142}
143
144#endif /* DROPBEAR_TCP_ACCEPT */
145