/* $NetBSD: rsh.c,v 1.11 1997/07/06 19:31:29 christos Exp $ */ /*- * Copyright (c) 1983, 1990, 1993, 1994 * The Regents of the University of California. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by the University of * California, Berkeley and its contributors. * 4. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ #include #ifndef lint __COPYRIGHT("@(#) Copyright (c) 1983, 1990, 1993, 1994\n\ The Regents of the University of California. All rights reserved.\n"); #endif /* not lint */ #ifndef lint #if 0 static char sccsid[] = "@(#)rsh.c 8.4 (Berkeley) 4/29/95"; #else __RCSID("$NetBSD: rsh.c,v 1.11 1997/07/06 19:31:29 christos Exp $"); #endif #endif /* not lint */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef __STDC__ #include #else #include #endif #include "pathnames.h" #ifdef KERBEROS #include #include CREDENTIALS cred; Key_schedule schedule; int use_kerberos = 1, doencrypt; char dst_realm_buf[REALM_SZ], *dest_realm; void warning __P((const char *, ...)); #endif /* * rsh - remote shell */ extern char *__progname; /* XXX */ int remerr; static int sigs[] = { SIGINT, SIGTERM, SIGQUIT }; char *copyargs __P((char **)); void sendsig __P((int)); int checkfd __P((struct pollfd *, int)); void talk __P((int, sigset_t *, pid_t, int)); void usage __P((void)); int main __P((int, char **)); int main(argc, argv) int argc; char **argv; { struct passwd *pw; struct servent *sp; sigset_t oset, nset; #ifdef IN_RCMD char *locuser = 0, *loop; #endif /* IN_RCMD */ int argoff, asrsh, ch, dflag, nflag, one, rem, i; pid_t pid; uid_t uid; char *args, *host, *p, *user, *name; argoff = asrsh = dflag = nflag = 0; one = 1; host = user = NULL; #ifndef IN_RCMD /* * If called as something other than "rsh" use it as the host name, * only for rsh. */ p = __progname; if (strcmp(p, "rsh") == 0) asrsh = 1; else host = p; #endif /* IN_RCMD */ /* handle "rsh host flags" */ if (!host && argc > 2 && argv[1][0] != '-') { host = argv[1]; argoff = 1; } #ifdef IN_RCMD if ((loop = getenv("RCMD_LOOP")) && strcmp(loop, "YES") == 0) warnx("rcmd appears to be looping!"); putenv("RCMD_LOOP=YES"); # ifdef KERBEROS # ifdef CRYPT # define OPTIONS "8KLdek:l:nu:wx" # else # define OPTIONS "8KLdek:l:nu:w" # endif # else # define OPTIONS "8KLdel:nu:w" # endif #else /* IN_RCMD */ # ifdef KERBEROS # ifdef CRYPT # define OPTIONS "8KLdek:l:nwx" # else # define OPTIONS "8KLdek:l:nw" # endif # else # define OPTIONS "8KLdel:nw" # endif #endif /* IN_RCMD */ if (!(pw = getpwuid(uid = getuid()))) errx(1, "unknown user id"); if ((name = strdup(pw->pw_name)) == NULL) err(1, "malloc"); while ((ch = getopt(argc - argoff, argv + argoff, OPTIONS)) != -1) switch(ch) { case 'K': #ifdef KERBEROS use_kerberos = 0; #endif break; case 'L': /* -8Lew are ignored to allow rlogin aliases */ case 'e': case 'w': case '8': break; case 'd': dflag = 1; break; case 'l': user = optarg; break; #ifdef KERBEROS case 'k': dest_realm = dst_realm_buf; strncpy(dest_realm, optarg, REALM_SZ); break; #endif case 'n': nflag = 1; break; #ifdef IN_RCMD case 'u': if (getuid() != 0 && optarg && name && strcmp(name, optarg) != 0) errx(1,"only super user can use the -u option"); locuser = optarg; break; #endif /* IN_RCMD */ #ifdef KERBEROS #ifdef CRYPT case 'x': doencrypt = 1; des_set_key((des_cblock *) cred.session, schedule); break; #endif #endif case '?': default: usage(); } optind += argoff; /* if haven't gotten a host yet, do so */ if (!host && !(host = argv[optind++])) usage(); /* if no further arguments, must have been called as rlogin. */ if (!argv[optind]) { #ifdef IN_RCMD usage(); #else if (asrsh) *argv = "rlogin"; execv(_PATH_RLOGIN, argv); err(1, "can't exec %s", _PATH_RLOGIN); #endif } argc -= optind; argv += optind; /* Accept user1@host format, though "-l user2" overrides user1 */ p = strchr(host, '@'); if (p) { *p = '\0'; if (!user && p > host) user = host; host = p + 1; if (*host == '\0') usage(); } if (!user) user = name; #ifdef KERBEROS #ifdef CRYPT /* -x turns off -n */ if (doencrypt) nflag = 0; #endif #endif args = copyargs(argv); sp = NULL; #ifdef KERBEROS if (use_kerberos) { sp = getservbyname((doencrypt ? "ekshell" : "kshell"), "tcp"); if (sp == NULL) { use_kerberos = 0; warning("can't get entry for %s/tcp service", doencrypt ? "ekshell" : "kshell"); } } #endif if (sp == NULL) sp = getservbyname("shell", "tcp"); if (sp == NULL) errx(1, "shell/tcp: unknown service"); #ifdef KERBEROS try_connect: if (use_kerberos) { #if 1 struct hostent *hp; /* fully qualify hostname (needed for krb_realmofhost) */ hp = gethostbyname(host); if (hp != NULL && !(host = strdup(hp->h_name))) err(1, "strdup"); #endif rem = KSUCCESS; errno = 0; if (dest_realm == NULL) dest_realm = krb_realmofhost(host); #ifdef CRYPT if (doencrypt) rem = krcmd_mutual(&host, sp->s_port, user, args, &remerr, dest_realm, &cred, schedule); else #endif rem = krcmd(&host, sp->s_port, user, args, &remerr, dest_realm); if (rem < 0) { use_kerberos = 0; sp = getservbyname("shell", "tcp"); if (sp == NULL) errx(1, "shell/tcp: unknown service"); if (errno == ECONNREFUSED) warning("remote host doesn't support Kerberos"); if (errno == ENOENT) warning("can't provide Kerberos auth data"); goto try_connect; } } else { if (doencrypt) errx(1, "the -x flag requires Kerberos authentication."); #ifdef IN_RCMD rem = orcmd(&host, sp->s_port, locuser ? locuser : #else rem = rcmd(&host, sp->s_port, #endif name, user, args, &remerr); } #else /* KERBEROS */ #ifdef IN_RCMD rem = orcmd(&host, sp->s_port, locuser ? locuser : #else rem = rcmd(&host, sp->s_port, #endif name, user, args, &remerr); #endif /* KERBEROS */ (void)free(name); if (rem < 0) exit(1); if (remerr < 0) errx(1, "can't establish stderr"); if (dflag) { if (setsockopt(rem, SOL_SOCKET, SO_DEBUG, &one, sizeof(one)) < 0) warn("setsockopt remote"); if (setsockopt(remerr, SOL_SOCKET, SO_DEBUG, &one, sizeof(one)) < 0) warn("setsockopt stderr"); } (void) setuid(uid); (void) sigemptyset(&nset); for (i = 0; i < sizeof(sigs) / sizeof(sigs[0]); i++) (void) sigaddset(&nset, sigs[i]); (void) sigprocmask(SIG_BLOCK, &nset, &oset); for (i = 0; i < sizeof(sigs) / sizeof(sigs[0]); i++) { struct sigaction sa; if (sa.sa_handler != SIG_IGN) { sa.sa_handler = sendsig; (void) sigaction(sigs[i], &sa, NULL); } } if (!nflag) { pid = fork(); if (pid < 0) err(1, "fork"); } else pid = -1; #if defined(KERBEROS) && defined(CRYPT) if (!doencrypt) #endif { (void)ioctl(remerr, FIONBIO, &one); (void)ioctl(rem, FIONBIO, &one); } talk(nflag, &oset, pid, rem); if (!nflag) (void)kill(pid, SIGKILL); exit(0); } int checkfd(fdp, outfd) struct pollfd *fdp; int outfd; { int nr, nw; char buf[BUFSIZ]; if (fdp->revents & (POLLNVAL|POLLERR|POLLHUP)) return -1; if ((fdp->revents & POLLIN) == 0) return 0; errno = 0; #if defined(KERBEROS) && defined(CRYPT) if (doencrypt) nr = des_read(fdp->fd, buf, sizeof buf); else #endif nr = read(fdp->fd, buf, sizeof buf); if (nr <= 0) { if (errno != EAGAIN) return -1; else return 0; } else { char *bc = buf; while (nr) { if ((nw = write(outfd, bc, nr)) <= 0) return -1; nr -= nw; bc += nw; } return 0; } } void talk(nflag, oset, pid, rem) int nflag; sigset_t *oset; pid_t pid; int rem; { int nr, nw, nfds; struct pollfd fds[2], *fdp = &fds[0]; char *bp, buf[BUFSIZ]; if (!nflag && pid == 0) { (void)close(remerr); fdp->events = POLLOUT|POLLNVAL|POLLERR|POLLHUP; fdp->fd = rem; nr = 0; bp = buf; for (;;) { errno = 0; if (nr == 0) { if ((nr = read(0, buf, sizeof buf)) == 0) goto done; if (nr == -1) { if (errno == EIO) goto done; if (errno == EINTR) continue; err(1, "read"); } bp = buf; } rewrite: if (poll(fdp, 1, INFTIM) == -1) { if (errno != EINTR) err(1, "poll"); goto rewrite; } if (fdp->revents & (POLLNVAL|POLLERR|POLLHUP)) err(1, "poll"); if ((fdp->revents & POLLOUT) == 0) goto rewrite; #if defined(KERBEROS) && defined(CRYPT) if (doencrypt) nw = des_write(rem, bp, nr); else #endif nw = write(rem, bp, nr); if (nw < 0) { if (errno == EAGAIN) continue; err(1, "write"); } bp += nw; nr -= nw; } done: (void)shutdown(rem, 1); exit(0); } (void) sigprocmask(SIG_SETMASK, oset, NULL); fds[0].events = fds[1].events = POLLIN|POLLNVAL|POLLERR|POLLHUP; fds[0].fd = remerr; fds[1].fd = rem; fdp = &fds[0]; nfds = 2; do { if (poll(fdp, nfds, INFTIM) == -1) { if (errno != EINTR) err(1, "poll"); continue; } if (fds[0].events != 0 && checkfd(&fds[0], 2) == -1) { nfds--; fds[0].events = 0; fdp = &fds[1]; } if (fds[1].events != 0 && checkfd(&fds[1], 1) == -1) { nfds--; fds[1].events = 0; } } while (nfds); } void sendsig(sig) int sig; { char signo; signo = sig; #ifdef KERBEROS #ifdef CRYPT if (doencrypt) (void)des_write(remerr, &signo, 1); else #endif #endif (void)write(remerr, &signo, 1); } #ifdef KERBEROS /* VARARGS */ void #ifdef __STDC__ warning(const char *fmt, ...) #else warning(va_alist) va_dcl #endif { va_list ap; #ifndef __STDC__ const char *fmt; va_start(ap); fmt = va_arg(ap, const char *); #else va_start(ap, fmt); #endif (void) fprintf(stderr, "%s: warning, using standard rsh: ", __progname); (void) vfprintf(stderr, fmt, ap); va_end(ap); (void) fprintf(stderr, ".\n"); } #endif char * copyargs(argv) char **argv; { int cc; char **ap, *args, *p; cc = 0; for (ap = argv; *ap; ++ap) cc += strlen(*ap) + 1; if (!(args = malloc((u_int)cc))) err(1, "malloc"); for (p = args, *p = '\0', ap = argv; *ap; ++ap) { (void)strcpy(p, *ap); p += strlen(p); if (ap[1]) *p++ = ' '; } *p = '\0'; return (args); } void usage() { (void)fprintf(stderr, "usage: %s [-nd%s]%s[-l login]%s [login@]host %s\n", __progname, #ifdef KERBEROS #ifdef CRYPT "x", " [-k realm] ", #else "", " [-k realm] ", #endif #else "", " ", #endif #ifdef IN_RCMD " [-u locuser]", "command" #else "", "[command]" #endif ); exit(1); }