b6257e9e67
above the home dir which is only group acessable: directroy owner group permission /a root wheel 755 /a/b root b 750 < /a/b/c c b 700 /a/b/c/.rhosts c b 600 add getegid and initgroups before and setegid behind fopen to fix this. add <netgroup.h> for the prototype of innetgr.
576 lines
14 KiB
C
576 lines
14 KiB
C
/* $NetBSD: rcmd.c,v 1.17 1996/12/28 18:48:31 veego Exp $ */
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/*
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* Copyright (c) 1983, 1993, 1994
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#if defined(LIBC_SCCS) && !defined(lint)
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#if 0
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static char sccsid[] = "@(#)rcmd.c 8.3 (Berkeley) 3/26/94";
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#else
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static char *rcsid = "$NetBSD: rcmd.c,v 1.17 1996/12/28 18:48:31 veego Exp $";
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#endif
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#endif /* LIBC_SCCS and not lint */
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#include <sys/param.h>
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#include <sys/socket.h>
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#include <sys/stat.h>
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#include <sys/poll.h>
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#include <netinet/in.h>
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#include <arpa/inet.h>
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#include <netgroup.h>
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#include <signal.h>
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#include <fcntl.h>
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#include <netdb.h>
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#include <unistd.h>
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#include <pwd.h>
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#include <errno.h>
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#include <stdio.h>
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#include <ctype.h>
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#include <string.h>
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#include <syslog.h>
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int __ivaliduser __P((FILE *, u_int32_t, const char *, const char *));
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static int __icheckhost __P((u_int32_t, const char *));
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static char *__gethostloop __P((u_int32_t));
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int
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rcmd(ahost, rport, locuser, remuser, cmd, fd2p)
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char **ahost;
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u_short rport;
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const char *locuser, *remuser, *cmd;
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int *fd2p;
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{
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struct hostent *hp;
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struct sockaddr_in sin, from;
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struct pollfd reads[2];
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int oldmask;
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pid_t pid;
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int s, lport, timo;
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char c;
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pid = getpid();
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hp = gethostbyname(*ahost);
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if (hp == NULL) {
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herror(*ahost);
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return (-1);
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}
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*ahost = hp->h_name;
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oldmask = sigblock(sigmask(SIGURG));
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for (timo = 1, lport = IPPORT_RESERVED - 1;;) {
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s = rresvport(&lport);
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if (s < 0) {
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if (errno == EAGAIN)
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(void)fprintf(stderr,
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"rcmd: socket: All ports in use\n");
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else
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(void)fprintf(stderr, "rcmd: socket: %s\n",
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strerror(errno));
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sigsetmask(oldmask);
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return (-1);
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}
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fcntl(s, F_SETOWN, pid);
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sin.sin_len = sizeof(struct sockaddr_in);
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sin.sin_family = hp->h_addrtype;
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sin.sin_port = rport;
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bcopy(hp->h_addr_list[0], &sin.sin_addr, hp->h_length);
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if (connect(s, (struct sockaddr *)&sin, sizeof(sin)) >= 0)
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break;
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(void)close(s);
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if (errno == EADDRINUSE) {
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lport--;
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continue;
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}
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if (errno == ECONNREFUSED && timo <= 16) {
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(void)sleep(timo);
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timo *= 2;
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continue;
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}
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if (hp->h_addr_list[1] != NULL) {
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int oerrno = errno;
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(void)fprintf(stderr, "connect to address %s: ",
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inet_ntoa(sin.sin_addr));
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errno = oerrno;
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perror(0);
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hp->h_addr_list++;
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bcopy(hp->h_addr_list[0], &sin.sin_addr, hp->h_length);
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(void)fprintf(stderr, "Trying %s...\n",
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inet_ntoa(sin.sin_addr));
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continue;
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}
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(void)fprintf(stderr, "%s: %s\n", hp->h_name, strerror(errno));
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sigsetmask(oldmask);
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return (-1);
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}
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lport--;
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if (fd2p == 0) {
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write(s, "", 1);
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lport = 0;
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} else {
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char num[8];
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int s2 = rresvport(&lport), s3;
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int len = sizeof(from);
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if (s2 < 0)
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goto bad;
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listen(s2, 1);
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(void)snprintf(num, sizeof(num), "%d", lport);
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if (write(s, num, strlen(num)+1) != strlen(num)+1) {
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(void)fprintf(stderr,
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"rcmd: write (setting up stderr): %s\n",
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strerror(errno));
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(void)close(s2);
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goto bad;
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}
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reads[0].fd = s;
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reads[1].fd = s2;
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reads[0].events = reads[1].events = reads[0].revents =
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reads[1].revents = POLLIN;
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errno = 0;
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if (poll(reads, 2, INFTIM) < 1 ||
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(reads[1].revents & POLLIN) == 0) {
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if (errno != 0)
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(void)fprintf(stderr,
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"rcmd: poll (setting up stderr): %s\n",
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strerror(errno));
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else
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(void)fprintf(stderr,
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"poll: protocol failure in circuit setup\n");
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(void)close(s2);
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goto bad;
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}
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s3 = accept(s2, (struct sockaddr *)&from, &len);
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(void)close(s2);
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if (s3 < 0) {
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(void)fprintf(stderr,
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"rcmd: accept: %s\n", strerror(errno));
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lport = 0;
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goto bad;
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}
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*fd2p = s3;
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from.sin_port = ntohs(from.sin_port);
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if (from.sin_family != AF_INET ||
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from.sin_port >= IPPORT_RESERVED ||
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from.sin_port < IPPORT_RESERVED / 2) {
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(void)fprintf(stderr,
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"socket: protocol failure in circuit setup.\n");
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goto bad2;
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}
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}
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(void)write(s, locuser, strlen(locuser)+1);
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(void)write(s, remuser, strlen(remuser)+1);
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(void)write(s, cmd, strlen(cmd)+1);
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if (read(s, &c, 1) != 1) {
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(void)fprintf(stderr,
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"rcmd: %s: %s\n", *ahost, strerror(errno));
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goto bad2;
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}
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if (c != 0) {
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while (read(s, &c, 1) == 1) {
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(void)write(STDERR_FILENO, &c, 1);
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if (c == '\n')
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break;
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}
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goto bad2;
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}
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sigsetmask(oldmask);
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return (s);
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bad2:
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if (lport)
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(void)close(*fd2p);
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bad:
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(void)close(s);
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sigsetmask(oldmask);
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return (-1);
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}
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int
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rresvport(alport)
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int *alport;
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{
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struct sockaddr_in sin;
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int s;
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sin.sin_len = sizeof(struct sockaddr_in);
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sin.sin_family = AF_INET;
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sin.sin_addr.s_addr = INADDR_ANY;
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s = socket(AF_INET, SOCK_STREAM, 0);
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if (s < 0)
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return (-1);
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for (;;) {
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sin.sin_port = htons((u_short)*alport);
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if (bind(s, (struct sockaddr *)&sin, sizeof(sin)) >= 0)
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return (s);
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if (errno != EADDRINUSE) {
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(void)close(s);
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return (-1);
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}
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(*alport)--;
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if (*alport == IPPORT_RESERVED/2) {
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(void)close(s);
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errno = EAGAIN; /* close */
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return (-1);
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}
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}
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}
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int __check_rhosts_file = 1;
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char *__rcmd_errstr;
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int
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ruserok(rhost, superuser, ruser, luser)
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const char *rhost, *ruser, *luser;
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int superuser;
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{
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struct hostent *hp;
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char **ap;
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int i;
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#define MAXADDRS 35
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u_int32_t addrs[MAXADDRS + 1];
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if ((hp = gethostbyname(rhost)) == NULL)
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return (-1);
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for (i = 0, ap = hp->h_addr_list; *ap && i < MAXADDRS; ++ap, ++i)
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bcopy(*ap, &addrs[i], sizeof(addrs[i]));
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addrs[i] = 0;
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for (i = 0; i < MAXADDRS && addrs[i]; i++)
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if (iruserok(addrs[i], superuser, ruser, luser) == 0)
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return (0);
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return (-1);
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}
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/*
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* New .rhosts strategy: We are passed an ip address. We spin through
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* hosts.equiv and .rhosts looking for a match. When the .rhosts only
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* has ip addresses, we don't have to trust a nameserver. When it
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* contains hostnames, we spin through the list of addresses the nameserver
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* gives us and look for a match.
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*
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* Returns 0 if ok, -1 if not ok.
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*/
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int
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iruserok(raddr, superuser, ruser, luser)
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u_int32_t raddr;
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int superuser;
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const char *ruser, *luser;
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{
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register char *cp;
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struct stat sbuf;
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struct passwd *pwd;
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FILE *hostf;
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uid_t uid;
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gid_t gid;
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int first;
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char pbuf[MAXPATHLEN];
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first = 1;
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hostf = superuser ? NULL : fopen(_PATH_HEQUIV, "r");
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again:
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if (hostf) {
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if (__ivaliduser(hostf, raddr, luser, ruser) == 0) {
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(void)fclose(hostf);
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return (0);
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}
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(void)fclose(hostf);
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}
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if (first == 1 && (__check_rhosts_file || superuser)) {
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first = 0;
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if ((pwd = getpwnam(luser)) == NULL)
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return (-1);
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(void)strcpy(pbuf, pwd->pw_dir);
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(void)strcat(pbuf, "/.rhosts");
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/*
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* Change effective uid while opening .rhosts. If root and
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* reading an NFS mounted file system, can't read files that
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* are protected read/write owner only.
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*/
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uid = geteuid();
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gid = getegid();
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(void)setegid(pwd->pw_gid);
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initgroups(pwd->pw_name, pwd->pw_gid);
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(void)seteuid(pwd->pw_uid);
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hostf = fopen(pbuf, "r");
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(void)seteuid(uid);
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(void)setegid(gid);
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if (hostf == NULL)
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return (-1);
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/*
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* If not a regular file, or is owned by someone other than
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* user or root or if writeable by anyone but the owner, quit.
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*/
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cp = NULL;
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if (lstat(pbuf, &sbuf) < 0)
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cp = ".rhosts lstat failed";
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else if (!S_ISREG(sbuf.st_mode))
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cp = ".rhosts not regular file";
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else if (fstat(fileno(hostf), &sbuf) < 0)
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cp = ".rhosts fstat failed";
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else if (sbuf.st_uid && sbuf.st_uid != pwd->pw_uid)
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cp = "bad .rhosts owner";
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else if (sbuf.st_mode & (S_IWGRP|S_IWOTH))
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cp = ".rhosts writeable by other than owner";
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/* If there were any problems, quit. */
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if (cp) {
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__rcmd_errstr = cp;
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(void)fclose(hostf);
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return (-1);
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}
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goto again;
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}
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return (-1);
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}
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/*
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* XXX
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* Don't make static, used by lpd(8).
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*
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* Returns 0 if ok, -1 if not ok.
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*/
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int
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__ivaliduser(hostf, raddr, luser, ruser)
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FILE *hostf;
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u_int32_t raddr;
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const char *luser, *ruser;
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{
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register char *user, *p;
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int ch;
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char buf[MAXHOSTNAMELEN + 128]; /* host + login */
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const char *auser, *ahost;
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int hostok, userok;
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char *rhost = NULL;
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int firsttime = 1;
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char domain[MAXHOSTNAMELEN];
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getdomainname(domain, sizeof(domain));
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while (fgets(buf, sizeof(buf), hostf)) {
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p = buf;
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/* Skip lines that are too long. */
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if (strchr(p, '\n') == NULL) {
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while ((ch = getc(hostf)) != '\n' && ch != EOF)
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;
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continue;
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}
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while (*p != '\n' && *p != ' ' && *p != '\t' && *p != '\0') {
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*p = isupper(*p) ? tolower(*p) : *p;
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p++;
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}
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if (*p == ' ' || *p == '\t') {
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*p++ = '\0';
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while (*p == ' ' || *p == '\t')
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p++;
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user = p;
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while (*p != '\n' && *p != ' ' &&
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*p != '\t' && *p != '\0')
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p++;
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} else
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user = p;
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*p = '\0';
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if (p == buf)
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continue;
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auser = *user ? user : luser;
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ahost = buf;
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if (ahost[0] == '+')
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switch (ahost[1]) {
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case '\0':
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hostok = 1;
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break;
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case '@':
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if (firsttime) {
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rhost = __gethostloop(raddr);
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firsttime = 0;
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}
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if (rhost)
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hostok = innetgr(&ahost[2], rhost,
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NULL, domain);
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else
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hostok = 0;
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break;
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default:
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hostok = __icheckhost(raddr, &ahost[1]);
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break;
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}
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else if (ahost[0] == '-')
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switch (ahost[1]) {
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case '\0':
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hostok = -1;
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break;
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case '@':
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if (firsttime) {
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rhost = __gethostloop(raddr);
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firsttime = 0;
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}
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if (rhost)
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hostok = -innetgr(&ahost[2], rhost,
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NULL, domain);
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else
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hostok = 0;
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break;
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default:
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hostok = -__icheckhost(raddr, &ahost[1]);
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break;
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}
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else
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hostok = __icheckhost(raddr, ahost);
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if (auser[0] == '+')
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switch (auser[1]) {
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case '\0':
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userok = 1;
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break;
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case '@':
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userok = innetgr(&auser[2], NULL, ruser,
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domain);
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break;
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default:
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userok = strcmp(ruser, &auser[1]) == 0;
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break;
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}
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else if (auser[0] == '-')
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switch (auser[1]) {
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case '\0':
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userok = -1;
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break;
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case '@':
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userok = -innetgr(&auser[2], NULL, ruser,
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domain);
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break;
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default:
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userok = -(strcmp(ruser, &auser[1]) == 0);
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break;
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}
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else
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userok = strcmp(ruser, auser) == 0;
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/* Check if one component did not match */
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if (hostok == 0 || userok == 0)
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continue;
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/* Check if we got a forbidden pair */
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if (userok == -1 || hostok == -1)
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return -1;
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/* Check if we got a valid pair */
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if (hostok == 1 && userok == 1)
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return 0;
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}
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return -1;
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}
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/*
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* Returns "true" if match, 0 if no match.
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*/
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static int
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__icheckhost(raddr, lhost)
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u_int32_t raddr;
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const char *lhost;
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{
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register struct hostent *hp;
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register u_int32_t laddr;
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register char **pp;
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/* Try for raw ip address first. */
|
|
if (isdigit(*lhost) && (int32_t)(laddr = inet_addr(lhost)) != -1)
|
|
return (raddr == laddr);
|
|
|
|
/* Better be a hostname. */
|
|
if ((hp = gethostbyname(lhost)) == NULL)
|
|
return (0);
|
|
|
|
/* Spin through ip addresses. */
|
|
for (pp = hp->h_addr_list; *pp; ++pp)
|
|
if (!bcmp(&raddr, *pp, sizeof(u_int32_t)))
|
|
return (1);
|
|
|
|
/* No match. */
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* Return the hostname associated with the supplied address.
|
|
* Do a reverse lookup as well for security. If a loop cannot
|
|
* be found, pack the result of inet_ntoa() into the string.
|
|
*/
|
|
static char *
|
|
__gethostloop(raddr)
|
|
u_int32_t raddr;
|
|
{
|
|
static char remotehost[MAXHOSTNAMELEN];
|
|
struct hostent *hp;
|
|
struct in_addr in;
|
|
|
|
hp = gethostbyaddr((char *) &raddr, sizeof(raddr), AF_INET);
|
|
if (hp == NULL)
|
|
return (NULL);
|
|
|
|
/*
|
|
* Look up the name and check that the supplied
|
|
* address is in the list
|
|
*/
|
|
strncpy(remotehost, hp->h_name, sizeof(remotehost) - 1);
|
|
remotehost[sizeof(remotehost) - 1] = '\0';
|
|
hp = gethostbyname(remotehost);
|
|
if (hp == NULL)
|
|
return (NULL);
|
|
|
|
for (; hp->h_addr_list[0] != NULL; hp->h_addr_list++)
|
|
if (!bcmp(hp->h_addr_list[0], (caddr_t)&raddr, sizeof(raddr)))
|
|
return (remotehost);
|
|
|
|
/*
|
|
* either the DNS adminstrator has made a configuration
|
|
* mistake, or someone has attempted to spoof us
|
|
*/
|
|
in.s_addr = raddr;
|
|
syslog(LOG_NOTICE, "rcmd: address %s not listed for host %s",
|
|
inet_ntoa(in), hp->h_name);
|
|
return (NULL);
|
|
}
|