glibc/inet/rcmd.c
1995-02-18 01:27:10 +00:00

415 lines
10 KiB
C

/*
* Copyright (c) 1983, 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.
*/
#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)rcmd.c 8.3 (Berkeley) 3/26/94";
#endif /* LIBC_SCCS and not lint */
#include <sys/param.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <signal.h>
#include <fcntl.h>
#include <netdb.h>
#include <unistd.h>
#include <pwd.h>
#include <errno.h>
#include <stdio.h>
#include <ctype.h>
#include <string.h>
int __ivaliduser __P((FILE *, u_long, const char *, const char *));
static int __icheckhost __P((u_long, char *));
int
rcmd(ahost, rport, locuser, remuser, cmd, fd2p)
char **ahost;
u_short rport;
const char *locuser, *remuser, *cmd;
int *fd2p;
{
struct hostent *hp;
struct sockaddr_in sin, from;
fd_set reads;
long oldmask;
pid_t pid;
int s, lport, timo;
char c;
pid = getpid();
hp = gethostbyname(*ahost);
if (hp == NULL) {
herror(*ahost);
return (-1);
}
*ahost = hp->h_name;
oldmask = sigblock(sigmask(SIGURG));
for (timo = 1, lport = IPPORT_RESERVED - 1;;) {
s = rresvport(&lport);
if (s < 0) {
if (errno == EAGAIN)
(void)fprintf(stderr,
"rcmd: socket: All ports in use\n");
else
(void)fprintf(stderr, "rcmd: socket: %s\n",
strerror(errno));
sigsetmask(oldmask);
return (-1);
}
fcntl(s, F_SETOWN, pid);
sin.sin_family = hp->h_addrtype;
bcopy(hp->h_addr_list[0], &sin.sin_addr, hp->h_length);
sin.sin_port = rport;
if (connect(s, (struct sockaddr *)&sin, sizeof(sin)) >= 0)
break;
(void)close(s);
if (errno == EADDRINUSE) {
lport--;
continue;
}
if (errno == ECONNREFUSED && timo <= 16) {
(void)sleep(timo);
timo *= 2;
continue;
}
if (hp->h_addr_list[1] != NULL) {
int oerrno = errno;
(void)fprintf(stderr, "connect to address %s: ",
inet_ntoa(sin.sin_addr));
errno = oerrno;
perror(0);
hp->h_addr_list++;
bcopy(hp->h_addr_list[0], &sin.sin_addr, hp->h_length);
(void)fprintf(stderr, "Trying %s...\n",
inet_ntoa(sin.sin_addr));
continue;
}
(void)fprintf(stderr, "%s: %s\n", hp->h_name, strerror(errno));
sigsetmask(oldmask);
return (-1);
}
lport--;
if (fd2p == 0) {
write(s, "", 1);
lport = 0;
} else {
char num[8];
int s2 = rresvport(&lport), s3;
int len = sizeof(from);
if (s2 < 0)
goto bad;
listen(s2, 1);
(void)snprintf(num, sizeof(num), "%d", lport);
if (write(s, num, strlen(num)+1) != strlen(num)+1) {
(void)fprintf(stderr,
"rcmd: write (setting up stderr): %s\n",
strerror(errno));
(void)close(s2);
goto bad;
}
FD_ZERO(&reads);
FD_SET(s, &reads);
FD_SET(s2, &reads);
errno = 0;
if (select(1 + (s > s2 ? s : s2), &reads, 0, 0, 0) < 1 ||
!FD_ISSET(s2, &reads)) {
if (errno != 0)
(void)fprintf(stderr,
"rcmd: select (setting up stderr): %s\n",
strerror(errno));
else
(void)fprintf(stderr,
"select: protocol failure in circuit setup\n");
(void)close(s2);
goto bad;
}
s3 = accept(s2, (struct sockaddr *)&from, &len);
(void)close(s2);
if (s3 < 0) {
(void)fprintf(stderr,
"rcmd: accept: %s\n", strerror(errno));
lport = 0;
goto bad;
}
*fd2p = s3;
from.sin_port = ntohs((u_short)from.sin_port);
if (from.sin_family != AF_INET ||
from.sin_port >= IPPORT_RESERVED ||
from.sin_port < IPPORT_RESERVED / 2) {
(void)fprintf(stderr,
"socket: protocol failure in circuit setup.\n");
goto bad2;
}
}
(void)write(s, locuser, strlen(locuser)+1);
(void)write(s, remuser, strlen(remuser)+1);
(void)write(s, cmd, strlen(cmd)+1);
if (read(s, &c, 1) != 1) {
(void)fprintf(stderr,
"rcmd: %s: %s\n", *ahost, strerror(errno));
goto bad2;
}
if (c != 0) {
while (read(s, &c, 1) == 1) {
(void)write(STDERR_FILENO, &c, 1);
if (c == '\n')
break;
}
goto bad2;
}
sigsetmask(oldmask);
return (s);
bad2:
if (lport)
(void)close(*fd2p);
bad:
(void)close(s);
sigsetmask(oldmask);
return (-1);
}
int
rresvport(alport)
int *alport;
{
struct sockaddr_in sin;
int s;
sin.sin_family = AF_INET;
sin.sin_addr.s_addr = INADDR_ANY;
s = socket(AF_INET, SOCK_STREAM, 0);
if (s < 0)
return (-1);
for (;;) {
sin.sin_port = htons((u_short)*alport);
if (bind(s, (struct sockaddr *)&sin, sizeof(sin)) >= 0)
return (s);
if (errno != EADDRINUSE) {
(void)close(s);
return (-1);
}
(*alport)--;
if (*alport == IPPORT_RESERVED/2) {
(void)close(s);
errno = EAGAIN; /* close */
return (-1);
}
}
}
int __check_rhosts_file = 1;
char *__rcmd_errstr;
int
ruserok(rhost, superuser, ruser, luser)
const char *rhost, *ruser, *luser;
int superuser;
{
struct hostent *hp;
u_long addr;
char **ap;
if ((hp = gethostbyname(rhost)) == NULL)
return (-1);
for (ap = hp->h_addr_list; *ap; ++ap) {
bcopy(*ap, &addr, sizeof(addr));
if (iruserok(addr, superuser, ruser, luser) == 0)
return (0);
}
return (-1);
}
/*
* New .rhosts strategy: We are passed an ip address. We spin through
* hosts.equiv and .rhosts looking for a match. When the .rhosts only
* has ip addresses, we don't have to trust a nameserver. When it
* contains hostnames, we spin through the list of addresses the nameserver
* gives us and look for a match.
*
* Returns 0 if ok, -1 if not ok.
*/
int
iruserok(raddr, superuser, ruser, luser)
u_long raddr;
int superuser;
const char *ruser, *luser;
{
register char *cp;
struct stat sbuf;
struct passwd *pwd;
FILE *hostf;
uid_t uid;
int first;
first = 1;
hostf = superuser ? NULL : fopen(_PATH_HEQUIV, "r");
again:
if (hostf) {
if (__ivaliduser(hostf, raddr, luser, ruser) == 0) {
(void)fclose(hostf);
return (0);
}
(void)fclose(hostf);
}
if (first == 1 && (__check_rhosts_file || superuser)) {
char *pbuf;
size_t dirlen;
first = 0;
if ((pwd = getpwnam(luser)) == NULL)
return (-1);
dirlen = strlen (pwd->pw_dir);
pbuf = alloca (dirlen + sizeof "/.rhosts");
memcpy (pbuf, pwd->pw_dir, dirlen);
memcpy (pbuf + dirlen, "/.rhosts", sizeof "/.rhosts");
/*
* Change effective uid while opening .rhosts. If root and
* reading an NFS mounted file system, can't read files that
* are protected read/write owner only.
*/
uid = geteuid();
(void)seteuid(pwd->pw_uid);
hostf = fopen(pbuf, "r");
(void)seteuid(uid);
if (hostf == NULL)
return (-1);
/*
* If not a regular file, or is owned by someone other than
* user or root or if writeable by anyone but the owner, quit.
*/
cp = NULL;
if (lstat(pbuf, &sbuf) < 0)
cp = ".rhosts lstat failed";
else if (!S_ISREG(sbuf.st_mode))
cp = ".rhosts not regular file";
else if (fstat(fileno(hostf), &sbuf) < 0)
cp = ".rhosts fstat failed";
else if (sbuf.st_uid && sbuf.st_uid != pwd->pw_uid)
cp = "bad .rhosts owner";
else if (sbuf.st_mode & (S_IWGRP|S_IWOTH))
cp = ".rhosts writeable by other than owner";
/* If there were any problems, quit. */
if (cp) {
__rcmd_errstr = cp;
(void)fclose(hostf);
return (-1);
}
goto again;
}
return (-1);
}
/*
* XXX
* Don't make static, used by lpd(8).
*
* Returns 0 if ok, -1 if not ok.
*/
int
__ivaliduser(hostf, raddr, luser, ruser)
FILE *hostf;
u_long raddr;
const char *luser, *ruser;
{
register char *user, *p;
int ch;
char *buf = NULL;
size_t bufsize = 0;
ssize_t nread;
while ((nread = getline (&buf, &bufsize, hostf)) > 0) {
buf[bufsize - 1] = '\0'; /* Make sure it's terminated. */
p = buf;
while (*p != '\n' && *p != ' ' && *p != '\t' && *p != '\0') {
*p = isupper(*p) ? tolower(*p) : *p;
p++;
}
if (*p == ' ' || *p == '\t') {
*p++ = '\0';
while (*p == ' ' || *p == '\t')
p++;
user = p;
while (*p != '\n' && *p != ' ' &&
*p != '\t' && *p != '\0')
p++;
} else
user = p;
*p = '\0';
if (__icheckhost(raddr, buf) &&
strcmp(ruser, *user ? user : luser) == 0) {
free (buf);
return (0);
}
}
free (buf);
return (-1);
}
/*
* Returns "true" if match, 0 if no match.
*/
static int
__icheckhost(raddr, lhost)
u_long raddr;
register char *lhost;
{
register struct hostent *hp;
register u_long laddr;
register char **pp;
/* Try for raw ip address first. */
if (isdigit(*lhost) && (long)(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_long)))
return (1);
/* No match. */
return (0);
}