/* $OpenBSD: rsh.c,v 1.16 1997/08/06 06:43:41 deraadt Exp $ */ /*- * Copyright (c) 1983, 1990 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. */ #ifndef lint char copyright[] = "@(#) Copyright (c) 1983, 1990 The Regents of the University of California.\n\ All rights reserved.\n"; #endif /* not lint */ #ifndef lint /*static char sccsid[] = "from: @(#)rsh.c 5.24 (Berkeley) 7/1/91";*/ static char rcsid[] = "$OpenBSD: rsh.c,v 1.16 1997/08/06 06:43:41 deraadt Exp $"; #endif /* not lint */ #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 int errno; int rfd2; main(argc, argv) int argc; char **argv; { extern char *optarg; extern int optind; struct passwd *pw; struct servent *sp; int omask; int argoff, asrsh, ch, dflag, nflag, one, pid, rem, uid; register char *p; char *args, *host, *user, *copyargs(); void sendsig(); argoff = asrsh = dflag = nflag = 0; one = 1; host = user = NULL; /* if called as something other than "rsh", use it as the host name */ if (p = strrchr(argv[0], '/')) ++p; else p = argv[0]; if (strcmp(p, "rsh")) host = p; else asrsh = 1; /* handle "rsh host flags" */ if (!host && argc > 2 && argv[1][0] != '-') { host = argv[1]; argoff = 1; } #ifdef KERBEROS #define OPTIONS "8KLdek:l:nwx" #else #define OPTIONS "8KLdel:nw" #endif 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 KERBEROS case 'x': doencrypt = 1; desrw_set_key(&cred.session, schedule); break; #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]) { if (asrsh) *argv = "rlogin"; seteuid(getuid()); setuid(getuid()); execv(_PATH_RLOGIN, argv); (void)fprintf(stderr, "rsh: can't exec %s.\n", _PATH_RLOGIN); exit(1); } argc -= optind; argv += optind; if (geteuid()) { (void)fprintf(stderr, "rsh: must be setuid root.\n"); exit(1); } if (!(pw = getpwuid(uid = getuid()))) { (void)fprintf(stderr, "rsh: unknown user id.\n"); exit(1); } if (!user) user = pw->pw_name; #ifdef KERBEROS /* -x turns off -n */ if (doencrypt) nflag = 0; #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) { (void)fprintf(stderr, "rsh: shell/tcp: unknown service.\n"); exit(1); } (void) unsetenv("RSH"); /* no tricks with rcmd(3) */ #ifdef KERBEROS try_connect: if (use_kerberos) { rem = KSUCCESS; errno = 0; if (dest_realm == NULL) dest_realm = krb_realmofhost(host); if (doencrypt) rem = krcmd_mutual(&host, sp->s_port, user, args, &rfd2, dest_realm, &cred, schedule); else rem = krcmd(&host, sp->s_port, user, args, &rfd2, dest_realm); if (rem < 0) { use_kerberos = 0; sp = getservbyname("shell", "tcp"); if (sp == NULL) { (void)fprintf(stderr, "rsh: unknown service shell/tcp.\n"); exit(1); } 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) { (void)fprintf(stderr, "rsh: the -x flag requires Kerberos authentication.\n"); exit(1); } rem = rcmd(&host, sp->s_port, pw->pw_name, user, args, &rfd2); } #else rem = rcmd(&host, sp->s_port, pw->pw_name, user, args, &rfd2); #endif if (rem < 0) exit(1); if (rfd2 < 0) { (void)fprintf(stderr, "rsh: can't establish stderr.\n"); exit(1); } if (dflag) { if (setsockopt(rem, SOL_SOCKET, SO_DEBUG, &one, sizeof(one)) < 0) (void)fprintf(stderr, "rsh: setsockopt: %s.\n", strerror(errno)); if (setsockopt(rfd2, SOL_SOCKET, SO_DEBUG, &one, sizeof(one)) < 0) (void)fprintf(stderr, "rsh: setsockopt: %s.\n", strerror(errno)); } (void)seteuid(uid); (void)setuid(uid); omask = sigblock(sigmask(SIGINT)|sigmask(SIGQUIT)|sigmask(SIGTERM)); if (signal(SIGINT, SIG_IGN) != SIG_IGN) (void)signal(SIGINT, sendsig); if (signal(SIGQUIT, SIG_IGN) != SIG_IGN) (void)signal(SIGQUIT, sendsig); if (signal(SIGTERM, SIG_IGN) != SIG_IGN) (void)signal(SIGTERM, sendsig); if (!nflag) { pid = fork(); if (pid < 0) { (void)fprintf(stderr, "rsh: fork: %s.\n", strerror(errno)); exit(1); } } #ifdef KERBEROS if (!doencrypt) #endif { (void)ioctl(rfd2, FIONBIO, &one); (void)ioctl(rem, FIONBIO, &one); } talk(nflag, omask, pid, rem); if (!nflag) (void)kill(pid, SIGKILL); exit(0); } talk(nflag, omask, pid, rem) int nflag, pid; int omask; register int rem; { register int cc, wc; register char *bp; int readfrom, ready, rembits; char buf[BUFSIZ]; if (!nflag && pid == 0) { (void)close(rfd2); reread: errno = 0; if ((cc = read(0, buf, sizeof buf)) <= 0) goto done; bp = buf; rewrite: rembits = 1 << rem; if (select(rem + 1, 0, &rembits, 0, 0) < 0) { if (errno != EINTR) { (void)fprintf(stderr, "rsh: select: %s.\n", strerror(errno)); exit(1); } goto rewrite; } if ((rembits & (1 << rem)) == 0) goto rewrite; #ifdef KERBEROS if (doencrypt) wc = des_write(rem, bp, cc); else #endif wc = write(rem, bp, cc); if (wc < 0) { if (errno == EWOULDBLOCK) goto rewrite; goto done; } bp += wc; cc -= wc; if (cc == 0) goto reread; goto rewrite; done: (void)shutdown(rem, 1); exit(0); } (void)sigsetmask(omask); readfrom = (1 << rfd2) | (1 << rem); do { ready = readfrom; if (select(MAX(rfd2, rem) + 1, &ready, 0, 0, 0) < 0) { if (errno != EINTR) { (void)fprintf(stderr, "rsh: select: %s.\n", strerror(errno)); exit(1); } continue; } if (ready & (1 << rfd2)) { errno = 0; #ifdef KERBEROS if (doencrypt) cc = des_read(rfd2, buf, sizeof buf); else #endif cc = read(rfd2, buf, sizeof buf); if (cc <= 0) { if (errno != EWOULDBLOCK) readfrom &= ~(1 << rfd2); } else (void)write(2, buf, cc); } if (ready & (1 << rem)) { errno = 0; #ifdef KERBEROS if (doencrypt) cc = des_read(rem, buf, sizeof buf); else #endif cc = read(rem, buf, sizeof buf); if (cc <= 0) { if (errno != EWOULDBLOCK) readfrom &= ~(1 << rem); } else (void)write(1, buf, cc); } } while (readfrom); } void sendsig(signo) char signo; { int save_errno = errno; #ifdef KERBEROS if (doencrypt) (void)des_write(rfd2, &signo, 1); else #endif (void)write(rfd2, &signo, 1); errno = save_errno; } #ifdef KERBEROS /* VARARGS */ void #ifdef __STDC__ warning(const char *fmt, ...) #else warning(va_alist) va_dcl #endif { va_list ap; #ifndef __STDC__ char *fmt; #endif char myrealm[REALM_SZ]; if (krb_get_lrealm(myrealm, 0) != KSUCCESS) return; (void)fprintf(stderr, "rsh: warning, using standard rsh: "); #ifdef __STDC__ va_start(ap, fmt); #else va_start(ap); fmt = va_arg(ap, char *); #endif vfprintf(stderr, fmt, ap); va_end(ap); (void)fprintf(stderr, ".\n"); } #endif char * copyargs(argv) char **argv; { register int cc; register char **ap, *p; char *args, *malloc(); cc = 0; for (ap = argv; *ap; ++ap) cc += strlen(*ap) + 1; if (!(args = malloc((u_int)cc))) { (void)fprintf(stderr, "rsh: %s.\n", strerror(ENOMEM)); exit(1); } for (p = args, ap = argv; *ap; ++ap) { (void)strcpy(p, *ap); for (p = strcpy(p, *ap); *p; ++p); if (ap[1]) *p++ = ' '; } return(args); } usage() { (void)fprintf(stderr, "usage: rsh [-nd%s]%s[-l login] host [command]\n", #ifdef KERBEROS "x", " [-k realm] "); #else "", " "); #endif exit(1); }