usr/src/libexec/rshd/rshd.c

#ifndef lint
static char sccsid[] = "@(#)rshd.c	4.15 83/05/03";
#endif

#include <sys/ioctl.h>
#include <sys/param.h>
#include <sys/socket.h>

#include <netinet/in.h>

#include <stdio.h>
#include <errno.h>
#include <pwd.h>
#include <wait.h>
#include <signal.h>
#include <netdb.h>

int	errno;
int	reapchild();
struct	sockaddr_in sin = { AF_INET };
struct	passwd *getpwnam();
char	*index(), *rindex(), *sprintf();
int	options;
/* VARARGS 1 */
int	error();
/*
 * remote execute server:
 *	remuser\0
 *	locuser\0
 *	command\0
 *	data
 */
main(argc, argv)
	int argc;
	char **argv;
{
	int f;
	struct sockaddr_in from;
	struct servent *sp;

	sp = getservbyname("shell", "tcp");
	if (sp == 0) {
		fprintf(stderr, "rshd: tcp/shell: unknown service\n");
		exit(1);
	}
#ifndef DEBUG
	if (fork())
		exit(0);
	for (f = 0; f < 10; f++)
		(void) close(f);
	(void) open("/", 0);
	(void) dup2(0, 1);
	(void) dup2(0, 2);
	{ int t = open("/dev/tty", 2);
	  if (t >= 0) {
		ioctl(t, TIOCNOTTY, (char *)0);
		(void) close(t);
	  }
	}
#endif
	sin.sin_port = sp->s_port;
	argc--, argv++;
	if (argc > 0 && !strcmp(argv[0], "-d")) {
		options |= SO_DEBUG;
		argc--, argv++;
	}
	if (argc > 0) {
		int port = atoi(argv[0]);

		if (port < 0) {
			fprintf(stderr, "%s: bad port #\n", argv[0]);
			exit(1);
		}
		sin.sin_port = htons((u_short)port);
		argc--, argv++;
	}
	f = socket(AF_INET, SOCK_STREAM, 0, 0);
	if (f < 0) {
		perror("rshd: socket");
		exit(1);
	}
	if (options & SO_DEBUG && setsockopt(f, SOL_SOCKET, SO_DEBUG, 0, 0) < 0)
		perror("rshd: setsockopt (SO_DEBUG)");
	if (setsockopt(f, SOL_SOCKET, SO_KEEPALIVE, 0, 0) < 0)
		perror("rshd: setsockopt (SO_KEEPALIVE)");
	if (bind(f, (caddr_t)&sin, sizeof (sin), 0) < 0) {
		perror("rshd: bind");
		exit(1);
	}
	sigset(SIGCHLD, reapchild);
	listen(f, 10);
	for (;;) {
		int g, len = sizeof (from);

		g = accept(f, &from, &len, 0);
		if (g < 0) {
			if (errno == EINTR)
				continue;
			perror("rshd: accept");
			continue;
		}
		if (fork() == 0) {
			signal(SIGCHLD, SIG_IGN);
			close(f);
			doit(g, &from);
		}
		close(g);
	}
}

reapchild()
{
	union wait status;

	while (wait3(&status, WNOHANG, 0) > 0)
		;
}

char	username[20] = "USER=";
char	homedir[64] = "HOME=";
char	shell[64] = "SHELL=";
char	*envinit[] =
	    {homedir, shell, "PATH=:/usr/ucb:/bin:/usr/bin", username, 0};
char	**environ;

doit(f, fromp)
	int f;
	struct sockaddr_in *fromp;
{
	char cmdbuf[NCARGS+1], *cp;
	char locuser[16], remuser[16];
	struct passwd *pwd;
	int s, backoff;
	struct hostent *hp;
	short port;
	int pv[2], pid, ready, readfrom, cc;
	char buf[BUFSIZ], sig;
	int one = 1;

	(void) signal(SIGINT, SIG_DFL);
	(void) signal(SIGQUIT, SIG_DFL);
	(void) signal(SIGTERM, SIG_DFL);
#ifdef DEBUG
	{ int t = open("/dev/tty", 2);
	  if (t >= 0) {
		ioctl(t, TIOCNOTTY, (char *)0);
		(void) close(t);
	  }
	}
#endif
	fromp->sin_port = ntohs((u_short)fromp->sin_port);
	if (fromp->sin_family != AF_INET ||
	    fromp->sin_port >= IPPORT_RESERVED) {
		fprintf(stderr, "rshd: malformed from address\n");
		exit(1);
	}
	(void) alarm(60);
	port = 0;
	for (;;) {
		char c;
		if (read(f, &c, 1) != 1) {
			perror("rshd: read");
			shutdown(f, 1+1);
			exit(1);
		}
		if (c == 0)
			break;
		port = port * 10 + c - '0';
	}
	(void) alarm(0);
	if (port != 0) {
		int lport = IPPORT_RESERVED - 1, retryshift;
		s = rresvport(&lport);
		if (s < 0) {
			perror("rshd: can't get stderr port");
			exit(1);
		}
		if (port >= IPPORT_RESERVED) {
			fprintf(stderr, "rshd: 2nd port not reserved\n");
			exit(1);
		}
		fromp->sin_port = htons((u_short)port);
		if (connect(s, fromp, sizeof (*fromp), 0) < 0) {
			perror("rshd: connect");
			exit(1);
		}
	}
	dup2(f, 0);
	dup2(f, 1);
	dup2(f, 2);
	hp = gethostbyaddr(&fromp->sin_addr, sizeof (struct in_addr),
		fromp->sin_family);
	if (hp == 0) {
		error("Host name for your address unknown\n");
		exit(1);
	}
	getstr(remuser, sizeof(remuser), "remuser");
	getstr(locuser, sizeof(locuser), "locuser");
	getstr(cmdbuf, sizeof(cmdbuf), "command");
	setpwent();
	pwd = getpwnam(locuser);
	if (pwd == NULL) {
		error("Login incorrect.\n");
		exit(1);
	}
	endpwent();
	if (chdir(pwd->pw_dir) < 0) {
		error("No remote directory.\n");
		exit(1);
	}
	if (ruserok(hp->h_name, pwd->pw_uid == 0, remuser, locuser) < 0) {
		error("Permission denied.\n");
		exit(1);
	}
	(void) write(2, "\0", 1);
	if (port) {
		if (pipe(pv) < 0) {
			error("Can't make pipe.\n");
			exit(1);
		}
		pid = fork();
		if (pid == -1)  {
			error("Try again.\n");
			exit(1);
		}
		if (pid) {
			(void) close(0); (void) close(1); (void) close(2);
			(void) close(f); (void) close(pv[1]);
			readfrom = (1<<s) | (1<<pv[0]);
			ioctl(pv[1], FIONBIO, (char *)&one);
			/* should set s nbio! */
			do {
				ready = readfrom;
				if (select(16, &ready, 0, 0, 0) < 0)
					break;
				if (ready & (1<<s)) {
					if (read(s, &sig, 1) <= 0)
						readfrom &= ~(1<<s);
					else
						killpg(pid, sig);
				}
				if (ready & (1<<pv[0])) {
					errno = 0;
					cc = read(pv[0], buf, sizeof (buf));
					if (cc <= 0) {
						shutdown(s, 1+1);
						readfrom &= ~(1<<pv[0]);
					} else
						(void) write(s, buf, cc);
				}
			} while (readfrom);
			exit(0);
		}
		setpgrp(0, getpid());
		(void) close(s); (void) close(pv[0]);
		dup2(pv[1], 2);
	}
	if (*pwd->pw_shell == '\0')
		pwd->pw_shell = "/bin/sh";
	(void) close(f);
	initgroups(pwd->pw_name, pwd->pw_gid);
	(void) setgid(pwd->pw_gid);
	(void) setuid(pwd->pw_uid);
	environ = envinit;
	strncat(homedir, pwd->pw_dir, sizeof(homedir)-6);
	strncat(shell, pwd->pw_shell, sizeof(shell)-7);
	strncat(username, pwd->pw_name, sizeof(username)-6);
	cp = rindex(pwd->pw_shell, '/');
	if (cp)
		cp++;
	else
		cp = pwd->pw_shell;
	execl(pwd->pw_shell, cp, "-c", cmdbuf, 0);
	perror(pwd->pw_shell);
	exit(1);
protofail:
	error("rsh: protocol failure detected by remote\n");
	exit(1);
}

/* VARARGS 1 */
error(fmt)
	char *fmt;
{
	char buf[BUFSIZ];

	buf[0] = 1;
	(void) sprintf(buf+1, fmt);
	(void) write(2, buf, strlen(buf));
}

getstr(buf, cnt, err)
	char *buf;
	int cnt;
	char *err;
{
	char c;

	do {
		if (read(0, &c, 1) != 1)
			exit(1);
		*buf++ = c;
		if (--cnt == 0) {
			error("%s too long\n", err);
			exit(1);
		}
	} while (c != 0);
}
Commit	Line	Data
	1	#ifndef lint
	2	static char sccsid[] = "@(#)rshd.c 4.15 83/05/03";
	3	#endif
	4
	5	#include <sys/ioctl.h>
	6	#include <sys/param.h>
	7	#include <sys/socket.h>
	8
	9	#include <netinet/in.h>
	10
	11	#include <stdio.h>
	12	#include <errno.h>
	13	#include <pwd.h>
	14	#include <wait.h>
	15	#include <signal.h>
	16	#include <netdb.h>
	17
	18	int errno;
	19	int reapchild();
	20	struct sockaddr_in sin = { AF_INET };
	21	struct passwd *getpwnam();
	22	char index(), rindex(), *sprintf();
	23	int options;
	24	/* VARARGS 1 */
	25	int error();
	26	/*
	27	* remote execute server:
	28	* remuser\0
	29	* locuser\0
	30	* command\0
	31	* data
	32	*/
	33	main(argc, argv)
	34	int argc;
	35	char **argv;
	36	{
	37	int f;
	38	struct sockaddr_in from;
	39	struct servent *sp;
	40
	41	sp = getservbyname("shell", "tcp");
	42	if (sp == 0) {
	43	fprintf(stderr, "rshd: tcp/shell: unknown service\n");
	44	exit(1);
	45	}
	46	#ifndef DEBUG
	47	if (fork())
	48	exit(0);
	49	for (f = 0; f < 10; f++)
	50	(void) close(f);
	51	(void) open("/", 0);
	52	(void) dup2(0, 1);
	53	(void) dup2(0, 2);
	54	{ int t = open("/dev/tty", 2);
	55	if (t >= 0) {
	56	ioctl(t, TIOCNOTTY, (char *)0);
	57	(void) close(t);
	58	}
	59	}
	60	#endif
	61	sin.sin_port = sp->s_port;
	62	argc--, argv++;
	63	if (argc > 0 && !strcmp(argv[0], "-d")) {
	64	options \|= SO_DEBUG;
	65	argc--, argv++;
	66	}
	67	if (argc > 0) {
	68	int port = atoi(argv[0]);
	69
	70	if (port < 0) {
	71	fprintf(stderr, "%s: bad port #\n", argv[0]);
	72	exit(1);
	73	}
	74	sin.sin_port = htons((u_short)port);
	75	argc--, argv++;
	76	}
	77	f = socket(AF_INET, SOCK_STREAM, 0, 0);
	78	if (f < 0) {
	79	perror("rshd: socket");
	80	exit(1);
	81	}
	82	if (options & SO_DEBUG && setsockopt(f, SOL_SOCKET, SO_DEBUG, 0, 0) < 0)
	83	perror("rshd: setsockopt (SO_DEBUG)");
	84	if (setsockopt(f, SOL_SOCKET, SO_KEEPALIVE, 0, 0) < 0)
	85	perror("rshd: setsockopt (SO_KEEPALIVE)");
	86	if (bind(f, (caddr_t)&sin, sizeof (sin), 0) < 0) {
	87	perror("rshd: bind");
	88	exit(1);
	89	}
	90	sigset(SIGCHLD, reapchild);
	91	listen(f, 10);
	92	for (;;) {
	93	int g, len = sizeof (from);
	94
	95	g = accept(f, &from, &len, 0);
	96	if (g < 0) {
	97	if (errno == EINTR)
	98	continue;
	99	perror("rshd: accept");
	100	continue;
	101	}
	102	if (fork() == 0) {
	103	signal(SIGCHLD, SIG_IGN);
	104	close(f);
	105	doit(g, &from);
	106	}
	107	close(g);
	108	}
	109	}
	110
	111	reapchild()
	112	{
	113	union wait status;
	114
	115	while (wait3(&status, WNOHANG, 0) > 0)
	116	;
	117	}
	118
	119	char username[20] = "USER=";
	120	char homedir[64] = "HOME=";
	121	char shell[64] = "SHELL=";
	122	char *envinit[] =
	123	{homedir, shell, "PATH=:/usr/ucb:/bin:/usr/bin", username, 0};
	124	char **environ;
	125
	126	doit(f, fromp)
	127	int f;
	128	struct sockaddr_in *fromp;
	129	{
	130	char cmdbuf[NCARGS+1], *cp;
	131	char locuser[16], remuser[16];
	132	struct passwd *pwd;
	133	int s, backoff;
	134	struct hostent *hp;
	135	short port;
	136	int pv[2], pid, ready, readfrom, cc;
	137	char buf[BUFSIZ], sig;
	138	int one = 1;
	139
	140	(void) signal(SIGINT, SIG_DFL);
	141	(void) signal(SIGQUIT, SIG_DFL);
	142	(void) signal(SIGTERM, SIG_DFL);
	143	#ifdef DEBUG
	144	{ int t = open("/dev/tty", 2);
	145	if (t >= 0) {
	146	ioctl(t, TIOCNOTTY, (char *)0);
	147	(void) close(t);
	148	}
	149	}
	150	#endif
	151	fromp->sin_port = ntohs((u_short)fromp->sin_port);
	152	if (fromp->sin_family != AF_INET \|\|
	153	fromp->sin_port >= IPPORT_RESERVED) {
	154	fprintf(stderr, "rshd: malformed from address\n");
	155	exit(1);
	156	}
	157	(void) alarm(60);
	158	port = 0;
	159	for (;;) {
	160	char c;
	161	if (read(f, &c, 1) != 1) {
	162	perror("rshd: read");
	163	shutdown(f, 1+1);
	164	exit(1);
	165	}
	166	if (c == 0)
	167	break;
	168	port = port * 10 + c - '0';
	169	}
	170	(void) alarm(0);
	171	if (port != 0) {
	172	int lport = IPPORT_RESERVED - 1, retryshift;
	173	s = rresvport(&lport);
	174	if (s < 0) {
	175	perror("rshd: can't get stderr port");
	176	exit(1);
	177	}
	178	if (port >= IPPORT_RESERVED) {
	179	fprintf(stderr, "rshd: 2nd port not reserved\n");
	180	exit(1);
	181	}
	182	fromp->sin_port = htons((u_short)port);
	183	if (connect(s, fromp, sizeof (*fromp), 0) < 0) {
	184	perror("rshd: connect");
	185	exit(1);
	186	}
	187	}
	188	dup2(f, 0);
	189	dup2(f, 1);
	190	dup2(f, 2);
	191	hp = gethostbyaddr(&fromp->sin_addr, sizeof (struct in_addr),
	192	fromp->sin_family);
	193	if (hp == 0) {
	194	error("Host name for your address unknown\n");
	195	exit(1);
	196	}
	197	getstr(remuser, sizeof(remuser), "remuser");
	198	getstr(locuser, sizeof(locuser), "locuser");
	199	getstr(cmdbuf, sizeof(cmdbuf), "command");
	200	setpwent();
	201	pwd = getpwnam(locuser);
	202	if (pwd == NULL) {
	203	error("Login incorrect.\n");
	204	exit(1);
	205	}
	206	endpwent();
	207	if (chdir(pwd->pw_dir) < 0) {
	208	error("No remote directory.\n");
	209	exit(1);
	210	}
	211	if (ruserok(hp->h_name, pwd->pw_uid == 0, remuser, locuser) < 0) {
	212	error("Permission denied.\n");
	213	exit(1);
	214	}
	215	(void) write(2, "\0", 1);
	216	if (port) {
	217	if (pipe(pv) < 0) {
	218	error("Can't make pipe.\n");
	219	exit(1);
	220	}
	221	pid = fork();
	222	if (pid == -1) {
	223	error("Try again.\n");
	224	exit(1);
	225	}
	226	if (pid) {
	227	(void) close(0); (void) close(1); (void) close(2);
	228	(void) close(f); (void) close(pv[1]);
	229	readfrom = (1<<s) \| (1<<pv[0]);
	230	ioctl(pv[1], FIONBIO, (char *)&one);
	231	/* should set s nbio! */
	232	do {
	233	ready = readfrom;
	234	if (select(16, &ready, 0, 0, 0) < 0)
	235	break;
	236	if (ready & (1<<s)) {
	237	if (read(s, &sig, 1) <= 0)
	238	readfrom &= ~(1<<s);
	239	else
	240	killpg(pid, sig);
	241	}
	242	if (ready & (1<<pv[0])) {
	243	errno = 0;
	244	cc = read(pv[0], buf, sizeof (buf));
	245	if (cc <= 0) {
	246	shutdown(s, 1+1);
	247	readfrom &= ~(1<<pv[0]);
	248	} else
	249	(void) write(s, buf, cc);
	250	}
	251	} while (readfrom);
	252	exit(0);
	253	}
	254	setpgrp(0, getpid());
	255	(void) close(s); (void) close(pv[0]);
	256	dup2(pv[1], 2);
	257	}
	258	if (*pwd->pw_shell == '\0')
	259	pwd->pw_shell = "/bin/sh";
	260	(void) close(f);
	261	initgroups(pwd->pw_name, pwd->pw_gid);
	262	(void) setgid(pwd->pw_gid);
	263	(void) setuid(pwd->pw_uid);
	264	environ = envinit;
	265	strncat(homedir, pwd->pw_dir, sizeof(homedir)-6);
	266	strncat(shell, pwd->pw_shell, sizeof(shell)-7);
	267	strncat(username, pwd->pw_name, sizeof(username)-6);
	268	cp = rindex(pwd->pw_shell, '/');
	269	if (cp)
	270	cp++;
	271	else
	272	cp = pwd->pw_shell;
	273	execl(pwd->pw_shell, cp, "-c", cmdbuf, 0);
	274	perror(pwd->pw_shell);
	275	exit(1);
	276	protofail:
	277	error("rsh: protocol failure detected by remote\n");
	278	exit(1);
	279	}
	280
	281	/* VARARGS 1 */
	282	error(fmt)
	283	char *fmt;
	284	{
	285	char buf[BUFSIZ];
	286
	287	buf[0] = 1;
	288	(void) sprintf(buf+1, fmt);
	289	(void) write(2, buf, strlen(buf));
	290	}
	291
	292	getstr(buf, cnt, err)
	293	char *buf;
	294	int cnt;
	295	char *err;
	296	{
	297	char c;
	298
	299	do {
	300	if (read(0, &c, 1) != 1)
	301	exit(1);
	302	*buf++ = c;
	303	if (--cnt == 0) {
	304	error("%s too long\n", err);
	305	exit(1);
	306	}
	307	} while (c != 0);
	308	}