[821] | 1 | /* vi: set sw=4 ts=4: */
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| 2 | /* nc: mini-netcat - built from the ground up for LRP
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| 3 | Copyright (C) 1998 Charles P. Wright
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| 4 |
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| 5 | 0.0.1 6K It works.
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| 6 | 0.0.2 5K Smaller and you can also check the exit condition if you wish.
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| 7 | 0.0.3 Uses select()
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| 8 |
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| 9 | 19980918 Busy Boxed! Dave Cinege
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| 10 | 19990512 Uses Select. Charles P. Wright
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| 11 | 19990513 Fixes stdin stupidity and uses buffers. Charles P. Wright
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| 12 |
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| 13 | Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
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| 14 | */
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| 15 |
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| 16 | #include <stdio.h>
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| 17 | #include <stdlib.h>
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| 18 | #include <string.h>
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| 19 | #include <unistd.h>
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| 20 | #include <signal.h>
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| 21 |
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| 22 | #include <sys/types.h>
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| 23 | #include <sys/socket.h>
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| 24 | #include <netinet/in.h>
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| 25 | #include <arpa/inet.h>
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| 26 | #include <netdb.h>
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| 27 | #include <sys/ioctl.h>
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| 28 | #include "busybox.h"
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| 29 |
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| 30 | static void timeout(int signum)
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| 31 | {
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| 32 | bb_error_msg_and_die("Timed out");
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| 33 | }
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| 34 |
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| 35 | int nc_main(int argc, char **argv)
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| 36 | {
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| 37 | int do_listen = 0, lport = 0, delay = 0, wsecs = 0, tmpfd, opt, sfd, x;
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| 38 |
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| 39 | #ifdef CONFIG_NC_GAPING_SECURITY_HOLE
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| 40 | char *pr00gie = NULL;
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| 41 | #endif
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| 42 |
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| 43 | struct sockaddr_in address;
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| 44 | struct hostent *hostinfo;
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| 45 |
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| 46 | fd_set readfds, testfds;
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| 47 |
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| 48 | while ((opt = getopt(argc, argv, "lp:i:e:w:")) > 0) {
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| 49 | switch (opt) {
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| 50 | case 'l':
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| 51 | do_listen++;
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| 52 | break;
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| 53 | case 'p':
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| 54 | lport = bb_lookup_port(optarg, "tcp", 0);
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| 55 | break;
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| 56 | case 'i':
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| 57 | delay = atoi(optarg);
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| 58 | break;
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| 59 | #ifdef CONFIG_NC_GAPING_SECURITY_HOLE
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| 60 | case 'e':
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| 61 | pr00gie = optarg;
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| 62 | break;
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| 63 | #endif
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| 64 | case 'w':
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| 65 | wsecs = atoi(optarg);
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| 66 | break;
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| 67 | default:
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| 68 | bb_show_usage();
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| 69 | }
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| 70 | }
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| 71 |
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| 72 | if ((do_listen && optind != argc) || (!do_listen && optind + 2 != argc))
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| 73 | bb_show_usage();
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| 74 |
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| 75 | sfd = bb_xsocket(AF_INET, SOCK_STREAM, 0);
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| 76 | x = 1;
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| 77 | if (setsockopt(sfd, SOL_SOCKET, SO_REUSEADDR, &x, sizeof (x)) == -1)
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| 78 | bb_perror_msg_and_die("reuseaddr");
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| 79 | address.sin_family = AF_INET;
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| 80 |
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| 81 | if (wsecs) {
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| 82 | signal(SIGALRM, timeout);
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| 83 | alarm(wsecs);
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| 84 | }
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| 85 |
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| 86 | if (lport != 0) {
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| 87 | memset(&address.sin_addr, 0, sizeof(address.sin_addr));
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| 88 | address.sin_port = lport;
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| 89 |
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| 90 | bb_xbind(sfd, (struct sockaddr *) &address, sizeof(address));
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| 91 | }
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| 92 |
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| 93 | if (do_listen) {
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| 94 | socklen_t addrlen = sizeof(address);
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| 95 |
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| 96 | bb_xlisten(sfd, 1);
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| 97 | if ((tmpfd = accept(sfd, (struct sockaddr *) &address, &addrlen)) < 0)
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| 98 | bb_perror_msg_and_die("accept");
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| 99 |
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| 100 | close(sfd);
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| 101 | sfd = tmpfd;
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| 102 | } else {
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| 103 | hostinfo = xgethostbyname(argv[optind]);
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| 104 |
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| 105 | address.sin_addr = *(struct in_addr *) *hostinfo->h_addr_list;
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| 106 | address.sin_port = bb_lookup_port(argv[optind+1], "tcp", 0);
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| 107 |
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| 108 | if (connect(sfd, (struct sockaddr *) &address, sizeof(address)) < 0)
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| 109 | bb_perror_msg_and_die("connect");
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| 110 | }
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| 111 |
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| 112 | if (wsecs) {
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| 113 | alarm(0);
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| 114 | signal(SIGALRM, SIG_DFL);
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| 115 | }
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| 116 |
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| 117 | #ifdef CONFIG_NC_GAPING_SECURITY_HOLE
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| 118 | /* -e given? */
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| 119 | if (pr00gie) {
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| 120 | dup2(sfd, 0);
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| 121 | close(sfd);
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| 122 | dup2(0, 1);
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| 123 | dup2(0, 2);
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| 124 | execl(pr00gie, pr00gie, NULL);
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| 125 | /* Don't print stuff or it will go over the wire.... */
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| 126 | _exit(-1);
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| 127 | }
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| 128 | #endif /* CONFIG_NC_GAPING_SECURITY_HOLE */
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| 129 |
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| 130 | FD_ZERO(&readfds);
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| 131 | FD_SET(sfd, &readfds);
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| 132 | FD_SET(STDIN_FILENO, &readfds);
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| 133 |
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| 134 | while (1) {
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| 135 | int fd;
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| 136 | int ofd;
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| 137 | int nread;
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| 138 |
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| 139 | testfds = readfds;
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| 140 |
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| 141 | if (select(FD_SETSIZE, &testfds, NULL, NULL, NULL) < 0)
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| 142 | bb_perror_msg_and_die("select");
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| 143 |
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| 144 | for (fd = 0; fd < FD_SETSIZE; fd++) {
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| 145 | if (FD_ISSET(fd, &testfds)) {
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| 146 | if ((nread = safe_read(fd, bb_common_bufsiz1,
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| 147 | sizeof(bb_common_bufsiz1))) < 0)
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| 148 | {
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| 149 | bb_perror_msg_and_die(bb_msg_read_error);
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| 150 | }
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| 151 |
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| 152 | if (fd == sfd) {
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| 153 | if (nread == 0)
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| 154 | exit(0);
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| 155 | ofd = STDOUT_FILENO;
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| 156 | } else {
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| 157 | if (nread <= 0) {
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| 158 | shutdown(sfd, 1 /* send */ );
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| 159 | close(STDIN_FILENO);
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| 160 | FD_CLR(STDIN_FILENO, &readfds);
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| 161 | }
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| 162 | ofd = sfd;
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| 163 | }
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| 164 |
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| 165 | if (bb_full_write(ofd, bb_common_bufsiz1, nread) < 0)
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| 166 | bb_perror_msg_and_die(bb_msg_write_error);
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| 167 | if (delay > 0) {
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| 168 | sleep(delay);
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| 169 | }
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| 170 | }
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| 171 | }
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| 172 | }
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| 173 | }
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