1cca9484d

Rob Landley

2006-07-10

SOURCE BUG Duration: 35s

Subject

Upgrade netcat a lot. Make -e able to take the rest of the command line as what to exec. Add -f mode and a brief explanation of how to use it to replace minicom. Add -l -l mode so you can turn any command into a server. And group all of netcat's command line options under two CONFIG entries, so

SOURCE BUG

This commit was genuinely broken at the time (not related to our build system): scripts/config/mkconfigs.c (2005-08-01 - 2006-10-05 arasi) uretilen bbconfigopts.h icine .config satirlarini kacissiz, ham newline'larla gömüyordu - gecerli C degildi, busybox'un kendi bb_mkdep araci bile parse edemiyordu (7d219aab7 ile duzeltildi, mkconfigs shell scripte cevrildi)

→ Bu hatanin tam hikayesini ve duzeltme diffini gor

Binary

No binary (build failed)

Architecture & Compiler Flags

Architecture: x86_64-linux-gnu Compiler: gcc (Ubuntu 11.4.0-1ubuntu1~22.04.3) 11.4.0

—

Build Log

(log yok)

Commit Diff GitHub →

include/libbb.h +1 -0 include/usage.h +30 -12 networking/Config.in +12 -4 networking/nc.c +102 -100

include/libbb.h+1 -0

@@ -19,6 +19,7 @@
	#include <fcntl.h>
	#include <inttypes.h>
	#include <netdb.h>
+	#include <signal.h>
	#include <stdio.h>
	#include <stdlib.h>
	#include <stdarg.h>

include/usage.h+30 -12

@@ -2105,23 +2105,41 @@ USE_FEATURE_MDEV_CONFIG( \
	" or\n" \
	"$ nameif -c /etc/my_mactab_file\n" \

-	#ifdef CONFIG_NC_GAPING_SECURITY_HOLE
-	# define USAGE_NC_EXEC(a) a
+	#if ENABLE_NC_SERVER \|\| ENABLE_NC_EXTRA
+	#define NC_BR1 "["
+	#define NC_BR2 "]"
	#else
-	# define USAGE_NC_EXEC(a)
+	#define NC_BR1
+	#define NC_BR2
	#endif
+
	#define nc_trivial_usage \
-	"[OPTIONS] [IP] [port]"
+	"[" \
+	NC_BR1 USE_NC_SERVER("-lp")USE_NC_EXTRA("iwf") NC_BR2 \
+	" ["USE_NC_EXTRA("FILENAME\|")"{IPADDR PORTNUM}]"USE_NC_EXTRA(" [-e COMMAND]")
	#define nc_full_usage \
-	"Netcat opens a pipe to IP:port\n\n" \
-	"Options:\n" \
-	"\t-l\t\tlisten mode, for inbound connects\n" \
-	"\t-p PORT\t\tlocal port number\n" \
-	"\t-i SECS\t\tdelay interval for lines sent\n" \
-	USAGE_NC_EXEC( \
-	"\t-e PROG\t\tprogram to exec after connect (dangerous!)\n" \
+	"Netcat opens a pipe, either to IP:port\n\n" \
+	"Options:" \
+	USE_NC_EXTRA( \
+	"\n\t-e\t\texec rest of command line after connect\n" \
+	"\t-i SECS\t\tdelay interval for lines sent\n" \
+	"\t-w SECS\t\ttimeout for connect\n" \
+	"\t-f filename\tuse file (ala /dev/ttyS0) instead of network" \
	) \
-	"\t-w SECS\t\ttimeout for connects and final net reads"
+	USE_NC_SERVER( \
+	"\n\t-l\t\tlisten mode, for inbound connects\n" \
+	USE_NC_EXTRA("\t\t\t(use -l twice with -e for persistent server)\n") \
+	"\t-p PORT\t\tlocal port number" \
+	)
+
+
+	#define nc_notes_usage "" \
+	USE_NC_EXTRA( \
+	"To use netcat as a terminal emulator on a serial port:\n\n" \
+	"$ stty 115200 -F /dev/ttyS0\n" \
+	"$ stty raw -echo -ctlecho && nc -f /dev/ttyS0\n" \
+	) ""
+
	#define nc_example_usage \
	"$ nc foobar.somedomain.com 25\n" \
	"220 foobar ESMTP Exim 3.12 #1 Sat, 15 Apr 2000 00:03:02 -0600\n" \

networking/Config.in+12 -4

@@ -446,13 +446,21 @@ config CONFIG_NC
	A simple Unix utility which reads and writes data across network
	connections.

-	config CONFIG_NC_GAPING_SECURITY_HOLE
-	bool "gaping security hole"
+	config CONFIG_NC_SERVER
+	bool "Netcat server options (-lp)"
	default n
	depends on CONFIG_NC
	help
-	Add support for executing a program after making or receiving a
-	successful connection (-e option).
+	Allow netcat to act as a server.
+
+	config CONFIG_NC_EXTRA
+	bool "Netcat extensions (-eiw and filename)"
+	default n
+	depends on CONFIG_NC
+	help
+	Add -e (support for executing the rest of the command line after
+	making or receiving a successful connection), -i (delay interval for
+	lines sent), -w (timeout for initial connection).

	config CONFIG_NETSTAT
	bool "netstat"

networking/nc.c+102 -100

@@ -1,32 +1,16 @@
	/* 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
-
-	Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
-	*/
-
-	#include <stdio.h>
-	#include <stdlib.h>
-	#include <string.h>
-	#include <unistd.h>
-	#include <signal.h>
-
-	#include <sys/types.h>
-	#include <sys/socket.h>
-	#include <netinet/in.h>
-	#include <arpa/inet.h>
-	#include <netdb.h>
-	#include <sys/ioctl.h>
+	*
+	* Copyright (C) 1998, 1999 Charles P. Wright
+	* Copyright (C) 1998 Dave Cinege
+	*
+	* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
+	*/
+
	#include "busybox.h"

+	#define xread bb_xread
+
	static void timeout(int signum)
	{
	bb_error_msg_and_die("Timed out");
@@ -34,79 +18,87 @@ static void timeout(int signum)

	int nc_main(int argc, char **argv)
	{
-	int do_listen = 0, lport = 0, delay = 0, wsecs = 0, tmpfd, opt, sfd, x;
-
-	#ifdef CONFIG_NC_GAPING_SECURITY_HOLE
-	char *pr00gie = NULL;
-	#endif
-
+	int do_listen = 0, lport = 0, delay = 0, wsecs = 0, execflag = 0, opt,
+	sfd = 0, cfd;
	struct sockaddr_in address;
	struct hostent *hostinfo;
-
	fd_set readfds, testfds;
+	char *infile = NULL;

-	while ((opt = getopt(argc, argv, "lp:i:e:w:")) > 0) {
-	switch (opt) {
-	case 'l':
-	do_listen++;
-	break;
-	case 'p':
+	memset(&address, 0, sizeof(address));
+
+	if (ENABLE_NC_SERVER \|\| ENABLE_NC_EXTRA) {
+	while ((opt = getopt(argc, argv, "lp:" USE_NC_EXTRA("i:ew:f:"))) > 0) {
+	if (ENABLE_NC_SERVER && opt=='l') do_listen++;
+	else if (ENABLE_NC_SERVER && opt=='p')
	lport = bb_lookup_port(optarg, "tcp", 0);
+	else if (ENABLE_NC_EXTRA && opt=='w') wsecs = atoi(optarg);
+	else if (ENABLE_NC_EXTRA && opt=='i') delay = atoi(optarg);
+	else if (ENABLE_NC_EXTRA && opt=='f') infile = optarg;
+	else if (ENABLE_NC_EXTRA && opt=='e' && optind!=argc) {
+	execflag++;
	break;
-	case 'i':
-	delay = atoi(optarg);
-	break;
-	#ifdef CONFIG_NC_GAPING_SECURITY_HOLE
-	case 'e':
-	pr00gie = optarg;
-	break;
-	#endif
-	case 'w':
-	wsecs = atoi(optarg);
-	break;
-	default:
-	bb_show_usage();
+	} else bb_show_usage();
	}
	}

-	if ((do_listen && optind != argc) \|\| (!do_listen && optind + 2 != argc))
-	bb_show_usage();
+
+	// For listen or file we need zero arguments, dialout is 2.
+	// For exec we need at least one more argument at the end, more ok

-	sfd = bb_xsocket(AF_INET, SOCK_STREAM, 0);
-	x = 1;
-	if (setsockopt(sfd, SOL_SOCKET, SO_REUSEADDR, &x, sizeof (x)) == -1)
-	bb_perror_msg_and_die("reuseaddr");
-	address.sin_family = AF_INET;
+	opt = (do_listen \|\| infile) ? 0 : 2 + execflag;
+	if (execflag ? argc-optind < opt : argc-optind!=opt \|\|
+	(infile && do_listen))
+	bb_show_usage();

	if (wsecs) {
	signal(SIGALRM, timeout);
	alarm(wsecs);
	}
+
+	if (infile) cfd = bb_xopen(infile, O_RDWR);
+	else {
+	opt = 1;
+	sfd = bb_xsocket(AF_INET, SOCK_STREAM, 0);
+	fcntl(sfd, F_SETFD, FD_CLOEXEC);
+	setsockopt(sfd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof (opt));
+	address.sin_family = AF_INET;

-	if (lport != 0) {
-	memset(&address.sin_addr, 0, sizeof(address.sin_addr));
-	address.sin_port = lport;
+	// Set local port.

-	bb_xbind(sfd, (struct sockaddr *) &address, sizeof(address));
-	}
+	if (lport != 0) {
+	address.sin_port = lport;
+
+	bb_xbind(sfd, (struct sockaddr *) &address, sizeof(address));
+	}
+
+	if (do_listen) {
+	socklen_t addrlen = sizeof(address);
+
+	bb_xlisten(sfd, do_listen);

-	if (do_listen) {
-	socklen_t addrlen = sizeof(address);
+	// If we didn't specify a port number, query and print it to stderr.

-	bb_xlisten(sfd, 1);
-	if ((tmpfd = accept(sfd, (struct sockaddr *) &address, &addrlen)) < 0)
-	bb_perror_msg_and_die("accept");
+	if (!lport) {
+	socklen_t len = sizeof(address);
+	getsockname(sfd, &address, &len);
+	fdprintf(2, "%d\n", SWAP_BE16(address.sin_port));
+	}
+	repeatyness:
+	if ((cfd = accept(sfd, (struct sockaddr *) &address, &addrlen)) < 0)
+	bb_perror_msg_and_die("accept");

-	close(sfd);
-	sfd = tmpfd;
-	} else {
-	hostinfo = xgethostbyname(argv[optind]);
+	if (!execflag) close(sfd);
+	} 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);
+	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");
+	if (connect(sfd, (struct sockaddr *) &address, sizeof(address)) < 0)
+	bb_perror_msg_and_die("connect");
+	cfd = sfd;
+	}
	}

	if (wsecs) {
@@ -114,24 +106,40 @@ int nc_main(int argc, char **argv)
	signal(SIGALRM, SIG_DFL);
	}

-	#ifdef CONFIG_NC_GAPING_SECURITY_HOLE
	/* -e given? */
-	if (pr00gie) {
-	dup2(sfd, 0);
-	close(sfd);
+	if (execflag) {
+	if(cfd) {
+	signal(SIGCHLD, SIG_IGN);
+	dup2(cfd, 0);
+	close(cfd);
+	}
	dup2(0, 1);
	dup2(0, 2);
-	execl(pr00gie, pr00gie, NULL);
+
+	// With more than one -l, repeatedly act as server.
+
+	if (do_listen>1 && vfork()) {
+	// This is a bit weird as cleanup goes, since we wind up with no
+	// stdin/stdout/stderr. But it's small and shouldn't hurt anything.
+	// We check for cfd == 0 above.
+	close(0);
+	close(1);
+	close(2);
+
+	goto repeatyness;
+	}
+	execvp(argv[optind], argv+optind);
	/* Don't print stuff or it will go over the wire.... */
-	_exit(-1);
+	_exit(127);
	}
-	#endif /* CONFIG_NC_GAPING_SECURITY_HOLE */

+	// Select loop copying stdin to cfd, and cfd to stdout.
+
	FD_ZERO(&readfds);
-	FD_SET(sfd, &readfds);
+	FD_SET(cfd, &readfds);
	FD_SET(STDIN_FILENO, &readfds);

-	while (1) {
+	for (;;) {
	int fd;
	int ofd;
	int nread;
@@ -143,30 +151,24 @@ int nc_main(int argc, char **argv)

	for (fd = 0; fd < FD_SETSIZE; fd++) {
	if (FD_ISSET(fd, &testfds)) {
-	if ((nread = safe_read(fd, bb_common_bufsiz1,
-	sizeof(bb_common_bufsiz1))) < 0)
-	{
-	bb_perror_msg_and_die(bb_msg_read_error);
-	}
+	nread = xread(fd, bb_common_bufsiz1, sizeof(bb_common_bufsiz1));

-	if (fd == sfd) {
-	if (nread == 0)
-	exit(0);
+	if (fd == cfd) {
+	if (!nread) exit(0);
	ofd = STDOUT_FILENO;
	} else {
-	if (nread <= 0) {
-	shutdown(sfd, 1 /* send */ );
-	close(STDIN_FILENO);
+	if (!nread) {
+	// Close outgoing half-connection so they get EOF, but
+	// leave incoming alone so we can see response.
+	shutdown(cfd, 1);
	FD_CLR(STDIN_FILENO, &readfds);
	}
-	ofd = sfd;
+	ofd = cfd;
	}

	if (bb_full_write(ofd, bb_common_bufsiz1, nread) < 0)
	bb_perror_msg_and_die(bb_msg_write_error);
-	if (delay > 0) {
-	sleep(delay);
-	}
+	if (delay > 0) sleep(delay);
	}
	}
	}