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190 lines
4.4 KiB
C
190 lines
4.4 KiB
C
/* vi: set sw=4 ts=4: */
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/* nc: mini-netcat - built from the ground up for LRP
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Copyright (C) 1998 Charles P. Wright
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0.0.1 6K It works.
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0.0.2 5K Smaller and you can also check the exit condition if you wish.
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0.0.3 Uses select()
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19980918 Busy Boxed! Dave Cinege
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19990512 Uses Select. Charles P. Wright
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19990513 Fixes stdin stupidity and uses buffers. Charles P. Wright
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include <signal.h>
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#include <sys/types.h>
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#include <sys/socket.h>
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#include <netinet/in.h>
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#include <arpa/inet.h>
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#include <netdb.h>
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#include <sys/time.h>
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#include <sys/ioctl.h>
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#include "busybox.h"
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static void timeout(int signum)
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{
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bb_error_msg_and_die("Timed out");
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}
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int nc_main(int argc, char **argv)
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{
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int do_listen = 0, lport = 0, delay = 0, wsecs = 0, tmpfd, opt, sfd, x;
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#define buf bb_common_bufsiz1
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#ifdef CONFIG_NC_GAPING_SECURITY_HOLE
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char *pr00gie = NULL;
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#endif
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struct sockaddr_in address;
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struct hostent *hostinfo;
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fd_set readfds, testfds;
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while ((opt = getopt(argc, argv, "lp:i:e:w:")) > 0) {
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switch (opt) {
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case 'l':
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do_listen++;
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break;
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case 'p':
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lport = bb_lookup_port(optarg, "tcp", 0);
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break;
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case 'i':
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delay = atoi(optarg);
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break;
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#ifdef CONFIG_NC_GAPING_SECURITY_HOLE
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case 'e':
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pr00gie = optarg;
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break;
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#endif
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case 'w':
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wsecs = atoi(optarg);
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break;
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default:
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bb_show_usage();
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}
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}
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if ((do_listen && optind != argc) || (!do_listen && optind + 2 != argc))
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bb_show_usage();
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if ((sfd = socket(AF_INET, SOCK_STREAM, 0)) < 0)
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bb_perror_msg_and_die("socket");
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x = 1;
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if (setsockopt(sfd, SOL_SOCKET, SO_REUSEADDR, &x, sizeof (x)) == -1)
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bb_perror_msg_and_die("reuseaddr");
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address.sin_family = AF_INET;
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if (wsecs) {
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signal(SIGALRM, timeout);
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alarm(wsecs);
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}
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if (lport != 0) {
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memset(&address.sin_addr, 0, sizeof(address.sin_addr));
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address.sin_port = lport;
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if (bind(sfd, (struct sockaddr *) &address, sizeof(address)) < 0)
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bb_perror_msg_and_die("bind");
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}
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if (do_listen) {
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socklen_t addrlen = sizeof(address);
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if (listen(sfd, 1) < 0)
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bb_perror_msg_and_die("listen");
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if ((tmpfd = accept(sfd, (struct sockaddr *) &address, &addrlen)) < 0)
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bb_perror_msg_and_die("accept");
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close(sfd);
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sfd = tmpfd;
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} else {
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hostinfo = xgethostbyname(argv[optind]);
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address.sin_addr = *(struct in_addr *) *hostinfo->h_addr_list;
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address.sin_port = bb_lookup_port(argv[optind+1], "tcp", 0);
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if (connect(sfd, (struct sockaddr *) &address, sizeof(address)) < 0)
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bb_perror_msg_and_die("connect");
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}
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if (wsecs) {
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alarm(0);
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signal(SIGALRM, SIG_DFL);
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}
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#ifdef CONFIG_NC_GAPING_SECURITY_HOLE
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/* -e given? */
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if (pr00gie) {
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dup2(sfd, 0);
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close(sfd);
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dup2(0, 1);
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dup2(0, 2);
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execl(pr00gie, pr00gie, NULL);
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/* Don't print stuff or it will go over the wire.... */
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_exit(-1);
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}
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#endif /* CONFIG_NC_GAPING_SECURITY_HOLE */
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FD_ZERO(&readfds);
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FD_SET(sfd, &readfds);
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FD_SET(STDIN_FILENO, &readfds);
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while (1) {
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int fd;
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int ofd;
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int nread;
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testfds = readfds;
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if (select(FD_SETSIZE, &testfds, NULL, NULL, NULL) < 0)
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bb_perror_msg_and_die("select");
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for (fd = 0; fd < FD_SETSIZE; fd++) {
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if (FD_ISSET(fd, &testfds)) {
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if ((nread = safe_read(fd, buf, sizeof(buf))) < 0)
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bb_perror_msg_and_die(bb_msg_read_error);
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if (fd == sfd) {
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if (nread == 0)
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exit(0);
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ofd = STDOUT_FILENO;
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} else {
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if (nread <= 0) {
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shutdown(sfd, 1 /* send */ );
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close(STDIN_FILENO);
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FD_CLR(STDIN_FILENO, &readfds);
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}
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ofd = sfd;
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}
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if (bb_full_write(ofd, buf, nread) < 0)
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bb_perror_msg_and_die(bb_msg_write_error);
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if (delay > 0) {
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sleep(delay);
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}
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}
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}
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}
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}
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