/*- * Copyright (c) 1988, 1989, 1992, 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. * * @(#) Copyright (c) 1988, 1989, 1992, 1993, 1994 The Regents of the University of California. All rights reserved. * @(#)rshd.c 8.2 (Berkeley) 4/6/94 * $FreeBSD: src/libexec/rshd/rshd.c,v 1.30.2.5 2002/05/14 22:27:21 des Exp $ * $DragonFly: src/libexec/rshd/rshd.c,v 1.3 2003/11/14 03:54:31 dillon Exp $ */ /* * remote shell server: * [port]\0 * remuser\0 * locuser\0 * command\0 * data */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef LOGIN_CAP #include #endif /* wrapper for KAME-special getnameinfo() */ #ifndef NI_WITHSCOPEID #define NI_WITHSCOPEID 0 #endif int keepalive = 1; int log_success; /* If TRUE, log all successful accesses */ int sent_null; int no_delay; #ifdef CRYPT int doencrypt = 0; #endif union sockunion { struct sockinet { u_char si_len; u_char si_family; u_short si_port; } su_si; struct sockaddr_in su_sin; struct sockaddr_in6 su_sin6; }; #define su_len su_si.si_len #define su_family su_si.si_family #define su_port su_si.si_port void doit (union sockunion *); void error (const char *, ...); void getstr (char *, int, char *); int local_domain (char *); char *topdomain (char *); void usage (void); #define OPTIONS "alnDL" int main(argc, argv) int argc; char *argv[]; { extern int __check_rhosts_file; struct linger linger; int ch, on = 1, fromlen; struct sockaddr_storage from; openlog("rshd", LOG_PID | LOG_ODELAY, LOG_DAEMON); opterr = 0; while ((ch = getopt(argc, argv, OPTIONS)) != -1) switch (ch) { case 'a': /* ignored for compatibility */ break; case 'l': __check_rhosts_file = 0; break; case 'n': keepalive = 0; break; #ifdef CRYPT case 'x': doencrypt = 1; break; #endif case 'D': no_delay = 1; break; case 'L': log_success = 1; break; case '?': default: usage(); break; } argc -= optind; argv += optind; #ifdef CRYPT if (doencrypt) { syslog(LOG_ERR, "-k is required for -x"); exit(2); } #endif fromlen = sizeof (from); if (getpeername(0, (struct sockaddr *)&from, &fromlen) < 0) { syslog(LOG_ERR, "getpeername: %m"); exit(1); } if (keepalive && setsockopt(0, SOL_SOCKET, SO_KEEPALIVE, (char *)&on, sizeof(on)) < 0) syslog(LOG_WARNING, "setsockopt (SO_KEEPALIVE): %m"); linger.l_onoff = 1; linger.l_linger = 60; /* XXX */ if (setsockopt(0, SOL_SOCKET, SO_LINGER, (char *)&linger, sizeof (linger)) < 0) syslog(LOG_WARNING, "setsockopt (SO_LINGER): %m"); if (no_delay && setsockopt(0, IPPROTO_TCP, TCP_NODELAY, &on, sizeof(on)) < 0) syslog(LOG_WARNING, "setsockopt (TCP_NODELAY): %m"); doit((union sockunion *)&from); /* NOTREACHED */ return(0); } char username[20] = "USER="; char homedir[64] = "HOME="; char shell[64] = "SHELL="; char path[100] = "PATH="; char *envinit[] = {homedir, shell, path, username, 0}; char **environ; void doit(fromp) union sockunion *fromp; { extern char *__rcmd_errstr; /* syslog hook from libc/net/rcmd.c. */ struct passwd *pwd; u_short port; fd_set ready, readfrom; int cc, nfd, pv[2], pid, s; int one = 1; char *errorstr; char *cp, sig, buf[BUFSIZ]; char cmdbuf[NCARGS+1], locuser[16], remuser[16]; char fromhost[2 * MAXHOSTNAMELEN + 1]; char numericname[INET6_ADDRSTRLEN]; int af = fromp->su_family, err; #ifdef CRYPT int rc; int pv1[2], pv2[2]; #endif #ifdef LOGIN_CAP login_cap_t *lc; #endif (void) signal(SIGINT, SIG_DFL); (void) signal(SIGQUIT, SIG_DFL); (void) signal(SIGTERM, SIG_DFL); fromp->su_port = ntohs((u_short)fromp->su_port); if (af != AF_INET #ifdef INET6 && af != AF_INET6 #endif ) { syslog(LOG_ERR, "malformed \"from\" address (af %d)\n", af); exit(1); } err = getnameinfo((struct sockaddr *)fromp, fromp->su_len, numericname, sizeof(numericname), NULL, 0, NI_NUMERICHOST|NI_WITHSCOPEID); /* XXX: do 'err' check */ #ifdef IP_OPTIONS if (af == AF_INET) { u_char optbuf[BUFSIZ/3]; int optsize = sizeof(optbuf), ipproto, i; 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) && optsize != 0) { for (i = 0; i < optsize; ) { u_char c = optbuf[i]; if (c == IPOPT_LSRR || c == IPOPT_SSRR) { syslog(LOG_NOTICE, "connection refused from %s with IP option %s", numericname, c == IPOPT_LSRR ? "LSRR" : "SSRR"); exit(1); } if (c == IPOPT_EOL) break; i += (c == IPOPT_NOP) ? 1 : optbuf[i+1]; } } } #endif if (fromp->su_port >= IPPORT_RESERVED || fromp->su_port < IPPORT_RESERVED/2) { syslog(LOG_NOTICE|LOG_AUTH, "connection from %s on illegal port %u", numericname, fromp->su_port); exit(1); } (void) alarm(60); port = 0; s = 0; /* not set or used if port == 0 */ for (;;) { char c; if ((cc = read(STDIN_FILENO, &c, 1)) != 1) { if (cc < 0) syslog(LOG_NOTICE, "read: %m"); shutdown(0, 1+1); exit(1); } if (c == 0) break; port = port * 10 + c - '0'; } (void) alarm(0); if (port != 0) { int lport = IPPORT_RESERVED - 1; s = rresvport_af(&lport, af); if (s < 0) { syslog(LOG_ERR, "can't get stderr port: %m"); exit(1); } if (port >= IPPORT_RESERVED || port < IPPORT_RESERVED/2) { syslog(LOG_NOTICE|LOG_AUTH, "2nd socket from %s on unreserved port %u", numericname, port); exit(1); } fromp->su_port = htons(port); if (connect(s, (struct sockaddr *)fromp, fromp->su_len) < 0) { syslog(LOG_INFO, "connect second port %d: %m", port); exit(1); } } errorstr = NULL; realhostname_sa(fromhost, sizeof(fromhost) - 1, (struct sockaddr *)fromp, fromp->su_len); fromhost[sizeof(fromhost) - 1] = '\0'; #ifdef CRYPT if (doencrypt && af == AF_INET) { struct sockaddr_in local_addr; rc = sizeof(local_addr); if (getsockname(0, (struct sockaddr *)&local_addr, &rc) < 0) { syslog(LOG_ERR, "getsockname: %m"); error("rlogind: getsockname: %m"); exit(1); } authopts = KOPT_DO_MUTUAL; rc = krb_recvauth(authopts, 0, ticket, "rcmd", instance, &fromaddr, &local_addr, kdata, "", schedule, version); des_set_key(&kdata->session, schedule); } #endif (void) alarm(60); getstr(remuser, sizeof(remuser), "remuser"); getstr(locuser, sizeof(locuser), "locuser"); getstr(cmdbuf, sizeof(cmdbuf), "command"); (void) alarm(0); setpwent(); pwd = getpwnam(locuser); if (pwd == NULL) { syslog(LOG_INFO|LOG_AUTH, "%s@%s as %s: unknown login. cmd='%.80s'", remuser, fromhost, locuser, cmdbuf); if (errorstr == NULL) errorstr = "Login incorrect.\n"; goto fail; } #ifdef LOGIN_CAP lc = login_getpwclass(pwd); #endif if (chdir(pwd->pw_dir) < 0) { #ifdef LOGIN_CAP if (chdir("/") < 0 || login_getcapbool(lc, "requirehome", !!pwd->pw_uid)) { syslog(LOG_INFO|LOG_AUTH, "%s@%s as %s: no home directory. cmd='%.80s'", remuser, fromhost, locuser, cmdbuf); error("No remote home directory.\n"); exit(0); } #else (void) chdir("/"); #ifdef notdef syslog(LOG_INFO|LOG_AUTH, "%s@%s as %s: no home directory. cmd='%.80s'", remuser, fromhost, locuser, cmdbuf); error("No remote directory.\n"); exit(1); #endif #endif pwd->pw_dir = "/"; } if (errorstr || (pwd->pw_expire && time(NULL) >= pwd->pw_expire) || iruserok_sa(fromp, fromp->su_len, pwd->pw_uid == 0, remuser, locuser) < 0) { if (__rcmd_errstr) syslog(LOG_INFO|LOG_AUTH, "%s@%s as %s: permission denied (%s). cmd='%.80s'", remuser, fromhost, locuser, __rcmd_errstr, cmdbuf); else syslog(LOG_INFO|LOG_AUTH, "%s@%s as %s: permission denied. cmd='%.80s'", remuser, fromhost, locuser, cmdbuf); fail: if (errorstr == NULL) errorstr = "Login incorrect.\n"; error(errorstr, fromhost); exit(1); } if (pwd->pw_uid && !access(_PATH_NOLOGIN, F_OK)) { error("Logins currently disabled.\n"); exit(1); } #ifdef LOGIN_CAP if (lc != NULL && fromp->su_family == AF_INET) { /*XXX*/ char remote_ip[MAXHOSTNAMELEN]; strncpy(remote_ip, numericname, sizeof(remote_ip) - 1); remote_ip[sizeof(remote_ip) - 1] = 0; if (!auth_hostok(lc, fromhost, remote_ip)) { syslog(LOG_INFO|LOG_AUTH, "%s@%s as %s: permission denied (%s). cmd='%.80s'", remuser, fromhost, locuser, __rcmd_errstr, cmdbuf); error("Login incorrect.\n"); exit(1); } if (!auth_timeok(lc, time(NULL))) { error("Logins not available right now\n"); exit(1); } } #endif /* !LOGIN_CAP */ #if BSD > 43 /* before fork, while we're session leader */ if (setlogin(pwd->pw_name) < 0) syslog(LOG_ERR, "setlogin() failed: %m"); #endif (void) write(STDERR_FILENO, "\0", 1); sent_null = 1; if (port) { if (pipe(pv) < 0) { error("Can't make pipe.\n"); exit(1); } #ifdef CRYPT if (doencrypt) { if (pipe(pv1) < 0) { error("Can't make 2nd pipe.\n"); exit(1); } if (pipe(pv2) < 0) { error("Can't make 3rd pipe.\n"); exit(1); } } #endif pid = fork(); if (pid == -1) { error("Can't fork; try again.\n"); exit(1); } if (pid) { #ifdef CRYPT if (doencrypt) { static char msg[] = SECURE_MESSAGE; (void) close(pv1[1]); (void) close(pv2[1]); des_enc_write(s, msg, sizeof(msg) - 1, schedule, &kdata->session); } else #endif { (void) close(0); (void) close(1); } (void) close(2); (void) close(pv[1]); FD_ZERO(&readfrom); FD_SET(s, &readfrom); FD_SET(pv[0], &readfrom); if (pv[0] > s) nfd = pv[0]; else nfd = s; #ifdef CRYPT if (doencrypt) { FD_ZERO(&writeto); FD_SET(pv2[0], &writeto); FD_SET(pv1[0], &readfrom); nfd = MAX(nfd, pv2[0]); nfd = MAX(nfd, pv1[0]); } else #endif ioctl(pv[0], FIONBIO, (char *)&one); /* should set s nbio! */ nfd++; do { ready = readfrom; #ifdef CRYPT if (doencrypt) { wready = writeto; if (select(nfd, &ready, &wready, (fd_set *) 0, (struct timeval *) 0) < 0) break; } else #endif if (select(nfd, &ready, (fd_set *)0, (fd_set *)0, (struct timeval *)0) < 0) break; if (FD_ISSET(s, &ready)) { int ret; #ifdef CRYPT if (doencrypt) ret = des_enc_read(s, &sig, 1, schedule, &kdata->session); else #endif ret = read(s, &sig, 1); if (ret <= 0) FD_CLR(s, &readfrom); else killpg(pid, sig); } if (FD_ISSET(pv[0], &ready)) { errno = 0; cc = read(pv[0], buf, sizeof(buf)); if (cc <= 0) { shutdown(s, 1+1); FD_CLR(pv[0], &readfrom); } else { #ifdef CRYPT if (doencrypt) (void) des_enc_write(s, buf, cc, schedule, &kdata->session); else #endif (void) write(s, buf, cc); } } #ifdef CRYPT if (doencrypt && FD_ISSET(pv1[0], &ready)) { errno = 0; cc = read(pv1[0], buf, sizeof(buf)); if (cc <= 0) { shutdown(pv1[0], 1+1); FD_CLR(pv1[0], &readfrom); } else (void) des_enc_write(STDOUT_FILENO, buf, cc, schedule, &kdata->session); } if (doencrypt && FD_ISSET(pv2[0], &wready)) { errno = 0; cc = des_enc_read(STDIN_FILENO, buf, sizeof(buf), schedule, &kdata->session); if (cc <= 0) { shutdown(pv2[0], 1+1); FD_CLR(pv2[0], &writeto); } else (void) write(pv2[0], buf, cc); } #endif } while (FD_ISSET(s, &readfrom) || #ifdef CRYPT (doencrypt && FD_ISSET(pv1[0], &readfrom)) || #endif FD_ISSET(pv[0], &readfrom)); exit(0); } setpgrp(0, getpid()); (void) close(s); (void) close(pv[0]); #ifdef CRYPT if (doencrypt) { close(pv1[0]); close(pv2[0]); dup2(pv1[1], 1); dup2(pv2[1], 0); close(pv1[1]); close(pv2[1]); } #endif dup2(pv[1], 2); close(pv[1]); } if (*pwd->pw_shell == '\0') pwd->pw_shell = _PATH_BSHELL; environ = envinit; strncat(homedir, pwd->pw_dir, sizeof(homedir)-6); strcat(path, _PATH_DEFPATH); strncat(shell, pwd->pw_shell, sizeof(shell)-7); strncat(username, pwd->pw_name, sizeof(username)-6); cp = strrchr(pwd->pw_shell, '/'); if (cp) cp++; else cp = pwd->pw_shell; #ifdef LOGIN_CAP if (setusercontext(lc, pwd, pwd->pw_uid, LOGIN_SETALL) != 0) { syslog(LOG_ERR, "setusercontext: %m"); exit(1); } login_close(lc); #else (void) setgid((gid_t)pwd->pw_gid); initgroups(pwd->pw_name, pwd->pw_gid); (void) setuid((uid_t)pwd->pw_uid); #endif endpwent(); if (log_success || pwd->pw_uid == 0) { syslog(LOG_INFO|LOG_AUTH, "%s@%s as %s: cmd='%.80s'", remuser, fromhost, locuser, cmdbuf); } execl(pwd->pw_shell, cp, "-c", cmdbuf, 0); perror(pwd->pw_shell); exit(1); } /* * Report error to client. Note: can't be used until second socket has * connected to client, or older clients will hang waiting for that * connection first. */ #if __STDC__ #include #else #include #endif void #if __STDC__ error(const char *fmt, ...) #else error(fmt, va_alist) char *fmt; va_dcl #endif { va_list ap; int len; char *bp, buf[BUFSIZ]; #if __STDC__ va_start(ap, fmt); #else va_start(ap); #endif bp = buf; if (sent_null == 0) { *bp++ = 1; len = 1; } else len = 0; (void)vsnprintf(bp, sizeof(buf) - 1, fmt, ap); (void)write(STDERR_FILENO, buf, len + strlen(bp)); } void getstr(buf, cnt, err) char *buf, *err; int cnt; { char c; do { if (read(STDIN_FILENO, &c, 1) != 1) exit(1); *buf++ = c; if (--cnt == 0) { error("%s too long\n", err); exit(1); } } while (c != 0); } /* * 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. */ int local_domain(h) char *h; { char localhost[MAXHOSTNAMELEN]; char *p1, *p2; localhost[0] = 0; (void) gethostname(localhost, sizeof(localhost) - 1); localhost[sizeof(localhost) - 1] = '\0'; p1 = topdomain(localhost); p2 = topdomain(h); if (p1 == NULL || p2 == NULL || !strcasecmp(p1, p2)) return (1); return (0); } char * topdomain(h) char *h; { char *p, *maybe = NULL; int dots = 0; for (p = h + strlen(h); p >= h; p--) { if (*p == '.') { if (++dots == 2) return (p); maybe = p; } } return (maybe); } void usage() { syslog(LOG_ERR, "usage: rshd [-%s]", OPTIONS); exit(2); }