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
|
/* vi: set sw=4 ts=4: */
/* nc: mini-netcat - built from the ground up for LRP
Copyright (C) 1998 Charles P. Wright
0.0.1 6K It works.
0.0.2 5K Smaller and you can also check the exit condition if you wish.
0.0.3 Uses select()
19980918 Busy Boxed! Dave Cinege
19990512 Uses Select. Charles P. Wright
19990513 Fixes stdin stupidity and uses buffers. Charles P. Wright
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <sys/time.h>
#include <sys/ioctl.h>
#include "busybox.h"
#define GAPING_SECURITY_HOLE
int nc_main(int argc, char **argv)
{
int do_listen = 0, lport = 0, delay = 0, tmpfd, opt, sfd, x;
char buf[BUFSIZ];
#ifdef GAPING_SECURITY_HOLE
char * pr00gie = NULL;
#endif
struct sockaddr_in address;
struct hostent *hostinfo;
fd_set readfds, testfds;
while ((opt = getopt(argc, argv, "lp:i:e:")) > 0) {
switch (opt) {
case 'l':
do_listen++;
break;
case 'p':
lport = bb_lookup_port(optarg, "tcp", 0);
break;
case 'i':
delay = atoi(optarg);
break;
#ifdef GAPING_SECURITY_HOLE
case 'e':
pr00gie = optarg;
break;
#endif
default:
bb_show_usage();
}
}
#ifdef GAPING_SECURITY_HOLE
if (pr00gie) {
/* won't need stdin */
close (fileno(stdin));
}
#endif /* GAPING_SECURITY_HOLE */
if ((do_listen && optind != argc) || (!do_listen && optind + 2 != argc))
bb_show_usage();
if ((sfd = socket(AF_INET, SOCK_STREAM, 0)) < 0)
bb_perror_msg_and_die("socket");
x = 1;
if (setsockopt (sfd, SOL_SOCKET, SO_REUSEADDR, &x, sizeof (x)) == -1)
bb_perror_msg_and_die ("reuseaddr failed");
address.sin_family = AF_INET;
if (lport != 0) {
memset(&address.sin_addr, 0, sizeof(address.sin_addr));
address.sin_port = lport;
if (bind(sfd, (struct sockaddr *) &address, sizeof(address)) < 0)
bb_perror_msg_and_die("bind");
}
if (do_listen) {
socklen_t addrlen = sizeof(address);
if (listen(sfd, 1) < 0)
bb_perror_msg_and_die("listen");
if ((tmpfd = accept(sfd, (struct sockaddr *) &address, &addrlen)) < 0)
bb_perror_msg_and_die("accept");
close(sfd);
sfd = tmpfd;
} else {
hostinfo = xgethostbyname(argv[optind]);
address.sin_addr = *(struct in_addr *) *hostinfo->h_addr_list;
address.sin_port = bb_lookup_port(argv[optind+1], "tcp", 0);
if (connect(sfd, (struct sockaddr *) &address, sizeof(address)) < 0)
bb_perror_msg_and_die("connect");
}
#ifdef GAPING_SECURITY_HOLE
/* -e given? */
if (pr00gie) {
dup2(sfd, 0);
close(sfd);
dup2 (0, 1);
dup2 (0, 2);
execl (pr00gie, pr00gie, NULL);
/* Don't print stuff or it will go over the wire.... */
_exit(-1);
}
#endif /* GAPING_SECURITY_HOLE */
FD_ZERO(&readfds);
FD_SET(sfd, &readfds);
FD_SET(STDIN_FILENO, &readfds);
while (1) {
int fd;
int ofd;
int nread;
testfds = readfds;
if (select(FD_SETSIZE, &testfds, NULL, NULL, NULL) < 0)
bb_perror_msg_and_die("select");
for (fd = 0; fd < FD_SETSIZE; fd++) {
if (FD_ISSET(fd, &testfds)) {
if ((nread = safe_read(fd, buf, sizeof(buf))) < 0)
bb_perror_msg_and_die("read");
if (fd == sfd) {
if (nread == 0)
exit(0);
ofd = STDOUT_FILENO;
} else {
if (nread == 0)
shutdown(sfd, 1);
ofd = sfd;
}
if (bb_full_write(ofd, buf, nread) < 0)
bb_perror_msg_and_die("write");
if (delay > 0) {
sleep(delay);
}
}
}
}
}
|
