4.3BSD-Reno/src/libexec/rlogind/rlogind.c
/*
* Copyright (c) 1983, 1988, 1989 The Regents of the University of California.
* All rights reserved.
*
* Redistribution and use in source and binary forms are permitted
* provided that the above copyright notice and this paragraph are
* duplicated in all such forms and that any documentation,
* advertising materials, and other materials related to such
* distribution and use acknowledge that the software was developed
* by the University of California, Berkeley. The name of the
* University may not be used to endorse or promote products derived
* from this software without specific prior written permission.
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
* WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*/
#ifndef lint
char copyright[] =
"@(#) Copyright (c) 1983, 1988, 1989 The Regents of the University of California.\n\
All rights reserved.\n";
#endif /* not lint */
#ifndef lint
static char sccsid[] = "@(#)rlogind.c 5.48 (Berkeley) 6/27/90";
#endif /* not lint */
#ifdef KERBEROS
/* From:
* $Source: /mit/kerberos/ucb/mit/rlogind/RCS/rlogind.c,v $
* $Header: rlogind.c,v 5.0 89/06/26 18:31:01 kfall Locked $
*/
#endif
/*
* remote login server:
* \0
* remuser\0
* locuser\0
* terminal_type/speed\0
* data
*/
#define FD_SETSIZE 16 /* don't need many bits for select */
#include <sys/param.h>
#include <sys/stat.h>
#include <sys/socket.h>
#include <sys/wait.h>
#include <sys/file.h>
#include <sys/signal.h>
#include <sys/ioctl.h>
#include <sys/termios.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <errno.h>
#include <pwd.h>
#include <netdb.h>
#include <syslog.h>
#include <string.h>
#include <stdio.h>
#include <unistd.h>
#include "pathnames.h"
#ifndef TIOCPKT_WINDOW
#define TIOCPKT_WINDOW 0x80
#endif
#ifdef KERBEROS
#include <kerberosIV/des.h>
#include <kerberosIV/krb.h>
#define SECURE_MESSAGE "This rlogin session is using DES encryption for all transmissions.\r\n"
AUTH_DAT *kdata;
KTEXT ticket;
u_char auth_buf[sizeof(AUTH_DAT)];
u_char tick_buf[sizeof(KTEXT_ST)];
Key_schedule schedule;
int encrypt = 0, retval, use_kerberos = 0, vacuous = 0;
#define ARGSTR "alnkvx"
#else
#define ARGSTR "aln"
#endif /* KERBEROS */
char *env[2];
#define NMAX 30
char lusername[NMAX+1], rusername[NMAX+1];
static char term[64] = "TERM=";
#define ENVSIZE (sizeof("TERM=")-1) /* skip null for concatenation */
int keepalive = 1;
int check_all = 0;
extern int errno;
int reapchild();
struct passwd *getpwnam(), *pwd;
char *malloc();
main(argc, argv)
int argc;
char **argv;
{
extern int opterr, optind;
extern int _check_rhosts_file;
int ch;
int on = 1, fromlen;
struct sockaddr_in from;
openlog("rlogind", LOG_PID | LOG_CONS, LOG_AUTH);
opterr = 0;
while ((ch = getopt(argc, argv, ARGSTR)) != EOF)
switch (ch) {
case 'a':
check_all = 1;
break;
case 'l':
_check_rhosts_file = 0;
break;
case 'n':
keepalive = 0;
break;
#ifdef KERBEROS
case 'k':
use_kerberos = 1;
break;
case 'v':
vacuous = 1;
break;
case 'x':
encrypt = 1;
break;
#endif
case '?':
default:
usage();
break;
}
argc -= optind;
argv += optind;
#ifdef KERBEROS
if (use_kerberos && vacuous) {
usage();
fatal(STDERR_FILENO, "only one of -k and -v allowed", 0);
}
#endif
fromlen = sizeof (from);
if (getpeername(0, &from, &fromlen) < 0) {
syslog(LOG_ERR,"Can't get peer name of remote host: %m");
fatal(STDERR_FILENO, "Can't get peer name of remote host", 1);
}
if (keepalive &&
setsockopt(0, SOL_SOCKET, SO_KEEPALIVE, &on, sizeof (on)) < 0)
syslog(LOG_WARNING, "setsockopt (SO_KEEPALIVE): %m");
on = IPTOS_LOWDELAY;
if (setsockopt(0, IPPROTO_IP, IP_TOS, (char *)&on, sizeof(int)) < 0)
syslog(LOG_WARNING, "setsockopt (IP_TOS): %m");
doit(0, &from);
}
int child;
int cleanup();
int netf;
char line[MAXPATHLEN];
int confirmed;
extern char *inet_ntoa();
struct winsize win = { 0, 0, 0, 0 };
doit(f, fromp)
int f;
struct sockaddr_in *fromp;
{
int i, master, pid, on = 1;
int authenticated = 0, hostok = 0;
register struct hostent *hp;
char remotehost[2 * MAXHOSTNAMELEN + 1];
struct hostent hostent;
char c;
alarm(60);
read(f, &c, 1);
if (c != 0)
exit(1);
#ifdef KERBEROS
if (vacuous)
fatal(f, "Remote host requires Kerberos authentication", 0);
#endif
alarm(0);
fromp->sin_port = ntohs((u_short)fromp->sin_port);
hp = gethostbyaddr(&fromp->sin_addr, sizeof (struct in_addr),
fromp->sin_family);
if (hp == 0) {
/*
* Only the name is used below.
*/
hp = &hostent;
hp->h_name = inet_ntoa(fromp->sin_addr);
hostok++;
} else if (check_all || local_domain(hp->h_name)) {
/*
* If name returned by gethostbyaddr is in our domain,
* attempt to verify that we haven't been fooled by someone
* in a remote net; look up the name and check that this
* address corresponds to the name.
*/
strncpy(remotehost, hp->h_name, sizeof(remotehost) - 1);
remotehost[sizeof(remotehost) - 1] = 0;
hp = gethostbyname(remotehost);
if (hp)
for (; hp->h_addr_list[0]; hp->h_addr_list++)
if (!bcmp(hp->h_addr_list[0], (caddr_t)&fromp->sin_addr,
sizeof(fromp->sin_addr))) {
hostok++;
break;
}
} else
hostok++;
#ifdef KERBEROS
if (use_kerberos) {
if (!hostok)
fatal(f, "rlogind: Host address mismatch.", 0);
retval = do_krb_login(hp->h_name, fromp, encrypt);
if (retval == 0)
authenticated++;
else if (retval > 0)
fatal(f, krb_err_txt[retval], 0);
write(f, &c, 1);
confirmed = 1; /* we sent the null! */
} else
#endif
{
if (fromp->sin_family != AF_INET ||
fromp->sin_port >= IPPORT_RESERVED ||
fromp->sin_port < IPPORT_RESERVED/2) {
syslog(LOG_NOTICE, "Connection from %s on illegal port",
inet_ntoa(fromp->sin_addr));
fatal(f, "Permission denied", 0);
}
#ifdef IP_OPTIONS
{
u_char optbuf[BUFSIZ/3], *cp;
char lbuf[BUFSIZ], *lp;
int optsize = sizeof(optbuf), ipproto;
struct protoent *ip;
if ((ip = getprotobyname("ip")) != NULL)
ipproto = ip->p_proto;
else
ipproto = IPPROTO_IP;
if (getsockopt(0, ipproto, IP_OPTIONS, (char *)optbuf,
&optsize) == 0 && optsize != 0) {
lp = lbuf;
for (cp = optbuf; optsize > 0; cp++, optsize--, lp += 3)
sprintf(lp, " %2.2x", *cp);
syslog(LOG_NOTICE,
"Connection received using IP options (ignored):%s",
lbuf);
if (setsockopt(0, ipproto, IP_OPTIONS,
(char *)NULL, &optsize) != 0) {
syslog(LOG_ERR, "setsockopt IP_OPTIONS NULL: %m");
exit(1);
}
}
}
#endif
if (do_rlogin(hp->h_name) == 0 && hostok)
authenticated++;
}
if (confirmed == 0) {
write(f, "", 1);
confirmed = 1; /* we sent the null! */
}
#ifdef KERBEROS
if (encrypt)
(void) des_write(f, SECURE_MESSAGE, sizeof(SECURE_MESSAGE));
if (use_kerberos == 0)
#endif
if (!authenticated && !hostok)
write(f, "rlogind: Host address mismatch.\r\n",
sizeof("rlogind: Host address mismatch.\r\n") - 1);
netf = f;
pid = forkpty(&master, line, NULL, &win);
if (pid < 0) {
if (errno == ENOENT)
fatal(f, "Out of ptys", 0);
else
fatal(f, "Forkpty", 1);
}
if (pid == 0) {
if (f > 2) /* f should always be 0, but... */
(void) close(f);
setup_term(0);
if (authenticated) {
#ifdef KERBEROS
if (use_kerberos && (pwd->pw_uid == 0))
syslog(LOG_INFO|LOG_AUTH,
"ROOT Kerberos login from %s.%s@%s on %s\n",
kdata->pname, kdata->pinst, kdata->prealm,
hp->h_name);
#endif
execl(_PATH_LOGIN, "login", "-p",
"-h", hp->h_name, "-f", lusername, 0);
} else
execl(_PATH_LOGIN, "login", "-p",
"-h", hp->h_name, lusername, 0);
fatal(STDERR_FILENO, _PATH_LOGIN, 1);
/*NOTREACHED*/
}
#ifdef KERBEROS
/*
* If encrypted, don't turn on NBIO or the des read/write
* routines will croak.
*/
if (!encrypt)
#endif
ioctl(f, FIONBIO, &on);
ioctl(master, FIONBIO, &on);
ioctl(master, TIOCPKT, &on);
signal(SIGCHLD, cleanup);
protocol(f, master);
signal(SIGCHLD, SIG_IGN);
cleanup();
}
char magic[2] = { 0377, 0377 };
char oobdata[] = {TIOCPKT_WINDOW};
/*
* Handle a "control" request (signaled by magic being present)
* in the data stream. For now, we are only willing to handle
* window size changes.
*/
control(pty, cp, n)
int pty;
char *cp;
int n;
{
struct winsize w;
if (n < 4+sizeof (w) || cp[2] != 's' || cp[3] != 's')
return (0);
oobdata[0] &= ~TIOCPKT_WINDOW; /* we know he heard */
bcopy(cp+4, (char *)&w, sizeof(w));
w.ws_row = ntohs(w.ws_row);
w.ws_col = ntohs(w.ws_col);
w.ws_xpixel = ntohs(w.ws_xpixel);
w.ws_ypixel = ntohs(w.ws_ypixel);
(void)ioctl(pty, TIOCSWINSZ, &w);
return (4+sizeof (w));
}
/*
* rlogin "protocol" machine.
*/
protocol(f, p)
register int f, p;
{
char pibuf[1024+1], fibuf[1024], *pbp, *fbp;
register pcc = 0, fcc = 0;
int cc, nfd, n;
char cntl;
/*
* Must ignore SIGTTOU, otherwise we'll stop
* when we try and set slave pty's window shape
* (our controlling tty is the master pty).
*/
(void) signal(SIGTTOU, SIG_IGN);
send(f, oobdata, 1, MSG_OOB); /* indicate new rlogin */
if (f > p)
nfd = f + 1;
else
nfd = p + 1;
if (nfd > FD_SETSIZE) {
syslog(LOG_ERR, "select mask too small, increase FD_SETSIZE");
fatal(f, "internal error (select mask too small)", 0);
}
for (;;) {
fd_set ibits, obits, ebits, *omask;
FD_ZERO(&ebits);
FD_ZERO(&ibits);
FD_ZERO(&obits);
omask = (fd_set *)NULL;
if (fcc) {
FD_SET(p, &obits);
omask = &obits;
} else
FD_SET(f, &ibits);
if (pcc >= 0)
if (pcc) {
FD_SET(f, &obits);
omask = &obits;
} else
FD_SET(p, &ibits);
FD_SET(p, &ebits);
if ((n = select(nfd, &ibits, omask, &ebits, 0)) < 0) {
if (errno == EINTR)
continue;
fatal(f, "select", 1);
}
if (n == 0) {
/* shouldn't happen... */
sleep(5);
continue;
}
#define pkcontrol(c) ((c)&(TIOCPKT_FLUSHWRITE|TIOCPKT_NOSTOP|TIOCPKT_DOSTOP))
if (FD_ISSET(p, &ebits)) {
cc = read(p, &cntl, 1);
if (cc == 1 && pkcontrol(cntl)) {
cntl |= oobdata[0];
send(f, &cntl, 1, MSG_OOB);
if (cntl & TIOCPKT_FLUSHWRITE) {
pcc = 0;
FD_CLR(p, &ibits);
}
}
}
if (FD_ISSET(f, &ibits)) {
#ifdef KERBEROS
if (encrypt)
fcc = des_read(f, fibuf, sizeof(fibuf));
else
#endif
fcc = read(f, fibuf, sizeof(fibuf));
if (fcc < 0 && errno == EWOULDBLOCK)
fcc = 0;
else {
register char *cp;
int left, n;
if (fcc <= 0)
break;
fbp = fibuf;
top:
for (cp = fibuf; cp < fibuf+fcc-1; cp++)
if (cp[0] == magic[0] &&
cp[1] == magic[1]) {
left = fcc - (cp-fibuf);
n = control(p, cp, left);
if (n) {
left -= n;
if (left > 0)
bcopy(cp+n, cp, left);
fcc -= n;
goto top; /* n^2 */
}
}
FD_SET(p, &obits); /* try write */
}
}
if (FD_ISSET(p, &obits) && fcc > 0) {
cc = write(p, fbp, fcc);
if (cc > 0) {
fcc -= cc;
fbp += cc;
}
}
if (FD_ISSET(p, &ibits)) {
pcc = read(p, pibuf, sizeof (pibuf));
pbp = pibuf;
if (pcc < 0 && errno == EWOULDBLOCK)
pcc = 0;
else if (pcc <= 0)
break;
else if (pibuf[0] == 0) {
pbp++, pcc--;
#ifdef KERBEROS
if (!encrypt)
#endif
FD_SET(f, &obits); /* try write */
} else {
if (pkcontrol(pibuf[0])) {
pibuf[0] |= oobdata[0];
send(f, &pibuf[0], 1, MSG_OOB);
}
pcc = 0;
}
}
if ((FD_ISSET(f, &obits)) && pcc > 0) {
#ifdef KERBEROS
if (encrypt)
cc = des_write(f, pbp, pcc);
else
#endif
cc = write(f, pbp, pcc);
if (cc < 0 && errno == EWOULDBLOCK) {
/*
* This happens when we try write after read
* from p, but some old kernels balk at large
* writes even when select returns true.
*/
if (!FD_ISSET(p, &ibits))
sleep(5);
continue;
}
if (cc > 0) {
pcc -= cc;
pbp += cc;
}
}
}
}
cleanup()
{
char *p;
p = line + sizeof(_PATH_DEV) - 1;
if (logout(p))
logwtmp(p, "", "");
(void)chmod(line, 0666);
(void)chown(line, 0, 0);
*p = 'p';
(void)chmod(line, 0666);
(void)chown(line, 0, 0);
shutdown(netf, 2);
exit(1);
}
fatal(f, msg, syserr)
int f, syserr;
char *msg;
{
int len;
char buf[BUFSIZ], *bp = buf;
/*
* Prepend binary one to message if we haven't sent
* the magic null as confirmation.
*/
if (!confirmed)
*bp++ = '\01'; /* error indicator */
if (syserr)
len = sprintf(bp, "rlogind: %s: %s.\r\n",
msg, strerror(errno));
else
len = sprintf(bp, "rlogind: %s.\r\n", msg);
(void) write(f, buf, bp + len - buf);
exit(1);
}
do_rlogin(host)
char *host;
{
getstr(rusername, sizeof(rusername), "remuser too long");
getstr(lusername, sizeof(lusername), "locuser too long");
getstr(term+ENVSIZE, sizeof(term)-ENVSIZE, "Terminal type too long");
pwd = getpwnam(lusername);
if (pwd == NULL)
return(-1);
if (pwd->pw_uid == 0)
return(-1);
return(ruserok(host, 0, rusername, lusername));
}
getstr(buf, cnt, errmsg)
char *buf;
int cnt;
char *errmsg;
{
char c;
do {
if (read(0, &c, 1) != 1)
exit(1);
if (--cnt < 0)
fatal(STDOUT_FILENO, errmsg, 0);
*buf++ = c;
} while (c != 0);
}
extern char **environ;
setup_term(fd)
int fd;
{
register char *cp = index(term+ENVSIZE, '/');
char *speed;
struct termios tt;
#ifndef notyet
tcgetattr(fd, &tt);
if (cp) {
*cp++ = '\0';
speed = cp;
cp = index(speed, '/');
if (cp)
*cp++ = '\0';
cfsetspeed(&tt, atoi(speed));
}
tt.c_iflag = TTYDEF_IFLAG;
tt.c_oflag = TTYDEF_OFLAG;
tt.c_lflag = TTYDEF_LFLAG;
tcsetattr(fd, TCSAFLUSH, &tt);
#else
if (cp) {
*cp++ = '\0';
speed = cp;
cp = index(speed, '/');
if (cp)
*cp++ = '\0';
tcgetattr(fd, &tt);
cfsetspeed(&tt, atoi(speed));
tcsetattr(fd, TCSAFLUSH, &tt);
}
#endif
env[0] = term;
env[1] = 0;
environ = env;
}
#ifdef KERBEROS
#define VERSION_SIZE 9
/*
* Do the remote kerberos login to the named host with the
* given inet address
*
* Return 0 on valid authorization
* Return -1 on valid authentication, no authorization
* Return >0 for error conditions
*/
do_krb_login(host, dest, encrypt)
char *host;
struct sockaddr_in *dest;
int encrypt;
{
int rc;
char instance[INST_SZ], version[VERSION_SIZE];
long authopts = 0L; /* !mutual */
struct sockaddr_in faddr;
kdata = (AUTH_DAT *) auth_buf;
ticket = (KTEXT) tick_buf;
instance[0] = '*';
instance[1] = '\0';
if (encrypt) {
rc = sizeof(faddr);
if (getsockname(0, &faddr, &rc))
return(-1);
authopts = KOPT_DO_MUTUAL;
rc = krb_recvauth(
authopts, 0,
ticket, "rcmd",
instance, dest, &faddr,
kdata, "", schedule, version);
des_set_key(kdata->session, schedule);
} else {
rc = krb_recvauth(
authopts, 0,
ticket, "rcmd",
instance, dest, (struct sockaddr_in *) 0,
kdata, "", (bit_64 *) 0, version);
}
if (rc != KSUCCESS)
return(rc);
getstr(lusername, sizeof(lusername), "locuser");
/* get the "cmd" in the rcmd protocol */
getstr(term+ENVSIZE, sizeof(term)-ENVSIZE, "Terminal type");
pwd = getpwnam(lusername);
if (pwd == NULL)
return(-1);
/* returns nonzero for no access */
if (kuserok(kdata,lusername) != 0)
return(-1);
return(0);
}
#endif /* KERBEROS */
usage()
{
#ifdef KERBEROS
syslog(LOG_ERR, "usage: rlogind [-aln] [-k | -v]");
#else
syslog(LOG_ERR, "usage: rlogind [-aln]");
#endif
}
/*
* Check whether host h is in our local domain,
* defined as sharing the last two components of the domain part,
* or the entire domain part if the local domain has only one component.
* If either name is unqualified (contains no '.'),
* assume that the host is local, as it will be
* interpreted as such.
*/
local_domain(h)
char *h;
{
char localhost[MAXHOSTNAMELEN];
char *p1, *p2, *topdomain();
localhost[0] = 0;
(void) gethostname(localhost, sizeof(localhost));
p1 = topdomain(localhost);
p2 = topdomain(h);
if (p1 == NULL || p2 == NULL || !strcasecmp(p1, p2))
return(1);
return(0);
}
char *
topdomain(h)
char *h;
{
register char *p;
char *maybe = NULL;
int dots = 0;
for (p = h + strlen(h); p >= h; p--) {
if (*p == '.') {
if (++dots == 2)
return (p);
maybe = p;
}
}
return (maybe);
}