source: rtems/cpukit/libnetworking/libc/rcmd.c @ 396b80e

/*
 * 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.
 *
 *  $Id$
 */

#if HAVE_CONFIG_H
#include "config.h"
#endif

#if HAVE_DECL_RCMD

#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>
#include <rpc/rpc.h>
#include <sys/select.h>
#ifdef YP
#include <rpcsvc/yp_prot.h>
#include <rpcsvc/ypclnt.h>
#endif

#ifndef __rtems__
extern int innetgr( const char *, const char *, const char *, const char * );
#endif

#define max(a, b)       ((a > b) ? a : b)

#ifdef __rtems__
int rresvport(int *alport);
#define bzero(a,s)              memset((a),0,(s))
#define bcmp                    memcmp
#define bcopy(s,d,i)    memcpy(d,s,i)
#else /* __rtems__ */

int __ivaliduser(FILE *, u_int32_t, const char *, const char *);
static int __icheckhost(const struct sockaddr *, socklen_t, const char *);

#endif

int
rcmd(
        char **ahost,
        int rport,
        const char *locuser,
        const char *remuser,
        const char *cmd,
        int *fd2p )
{
        struct hostent *hp;
        struct sockaddr_in sin, from;
        fd_set reads;
#ifndef __rtems__
        long oldmask;
#endif
        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;
#ifndef __rtems__
        oldmask = sigblock(sigmask(SIGURG));
#endif
        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));
#ifndef __rtems__
                        sigsetmask(oldmask);
#endif
                        return (-1);
                }
                fcntl(s, F_SETOWN, pid);
                bzero(&sin, sizeof sin);
                sin.sin_len = sizeof(struct sockaddr_in);
                sin.sin_family = hp->h_addrtype;
                sin.sin_port = rport;
                bcopy(hp->h_addr_list[0], &sin.sin_addr, MIN(hp->h_length, sizeof sin.sin_addr));
                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, MIN(hp->h_length, sizeof sin.sin_addr));
                        (void)fprintf(stderr, "Trying %s...\n",
                            inet_ntoa(sin.sin_addr));
                        continue;
                }
                (void)fprintf(stderr, "%s: %s\n", hp->h_name, strerror(errno));
#ifndef __rtems__
                sigsetmask(oldmask);
#endif
                return (-1);
        }
        lport--;
        if (fd2p == 0) {
                write(s, "", 1);
                lport = 0;
        } else {
                char num[8];
                int s2 = rresvport(&lport), s3;
                socklen_t len = sizeof(from);
                int nfds;

                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;
                }
                nfds = max(s, s2)+1;
                if(nfds > FD_SETSIZE) {
                        fprintf(stderr, "rcmd: too many files\n");
                        (void)close(s2);
                        goto bad;
                }
again:
                FD_ZERO(&reads);
                FD_SET(s, &reads);
                FD_SET(s2, &reads);
                errno = 0;
                if (select(nfds, &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);
                /*
                 * XXX careful for ftp bounce attacks. If discovered, shut them
                 * down and check for the real auxiliary channel to connect.
                 */
                if (from.sin_family == AF_INET && from.sin_port == htons(20)) {
                        close(s3);
                        goto again;
                }
                (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;
        }
#ifndef __rtems__
        sigsetmask(oldmask);
#endif
        return (s);
bad2:
        if (lport)
                (void)close(*fd2p);
bad:
        (void)close(s);
#ifndef __rtems__
        sigsetmask(oldmask);
#endif
        return (-1);
}

int
rresvport(int *alport )
{
        struct sockaddr_in sin;
        int s;

        bzero(&sin, sizeof sin);
        sin.sin_len = sizeof(struct sockaddr_in);
        sin.sin_family = AF_INET;
        sin.sin_addr.s_addr = INADDR_ANY;
        s = socket(AF_INET, SOCK_STREAM, 0);
        if (s < 0)
                return (-1);
#if 0 /* compat_exact_traditional_rresvport_semantics */
        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);
        }
#endif
        sin.sin_port = 0;
        if (bindresvport(s, &sin) == -1) {
                (void)close(s);
                return (-1);
        }
        *alport = (int)ntohs(sin.sin_port);
        return (s);
}

#ifndef __rtems__
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;
        char pbuf[MAXPATHLEN];

        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)) {
                first = 0;
                if ((pwd = getpwnam(luser)) == NULL)
                        return (-1);
                (void)strcpy(pbuf, pwd->pw_dir);
                (void)strcat(pbuf, "/.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[MAXHOSTNAMELEN + 128];         /* host + login */
        char hname[MAXHOSTNAMELEN];
        struct hostent *hp;
        /* Presumed guilty until proven innocent. */
        int userok = 0, hostok = 0;
#ifdef YP
        char *ypdomain;

        if (yp_get_default_domain(&ypdomain))
                ypdomain = NULL;
#else
#define ypdomain NULL
#endif
        /* We need to get the damn hostname back for netgroup matching. */
        if ((hp = gethostbyaddr((char *)&raddr, sizeof(u_long),
                                                        AF_INET)) == NULL)
                return (-1);
        strncpy(hname, hp->h_name, sizeof(hname));
        hname[sizeof(hname) - 1] = '\0';

        while (fgets(buf, sizeof(buf), hostf)) {
                p = buf;
                /* Skip lines that are too long. */
                if (strchr(p, '\n') == NULL) {
                        while ((ch = getc(hostf)) != '\n' && ch != EOF);
                        continue;
                }
                if (*p == '\n' || *p == '#') {
                        /* comment... */
                        continue;
                }
                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';
                /*
                 * Do +/- and +@/-@ checking. This looks really nasty,
                 * but it matches SunOS's behavior so far as I can tell.
                 */
                switch(buf[0]) {
                case '+':
                        if (!buf[1]) {     /* '+' matches all hosts */
                                hostok = 1;
                                break;
                        }
                        if (buf[1] == '@')  /* match a host by netgroup */
                                hostok = innetgr((char *)&buf[2],
                                        (char *)&hname, NULL, ypdomain);
                        else            /* match a host by addr */
                                hostok = __icheckhost(raddr,(char *)&buf[1]);
                        break;
                case '-':     /* reject '-' hosts and all their users */
                        if (buf[1] == '@') {
                                if (innetgr((char *)&buf[2],
                                              (char *)&hname, NULL, ypdomain))
                                        return(-1);
                        } else {
                                if (__icheckhost(raddr,(char *)&buf[1]))
                                        return(-1);
                        }
                        break;
                default:  /* if no '+' or '-', do a simple match */
                        hostok = __icheckhost(raddr, buf);
                        break;
                }
                switch(*user) {
                case '+':
                        if (!*(user+1)) {      /* '+' matches all users */
                                userok = 1;
                                break;
                        }
                        if (*(user+1) == '@')  /* match a user by netgroup */
                                userok = innetgr(user+2, NULL, ruser, ypdomain);
                        else       /* match a user by direct specification */
                                userok = !(strcmp(ruser, user+1));
                        break;
                case '-':               /* if we matched a hostname, */
                        if (hostok) {   /* check for user field rejections */
                                if (!*(user+1))
                                        return(-1);
                                if (*(user+1) == '@') {
                                        if (innetgr(user+2, NULL,
                                                        ruser, ypdomain))
                                                return(-1);
                                } else {
                                        if (!strcmp(ruser, user+1))
                                                return(-1);
                                }
                        }
                        break;
                default:        /* no rejections: try to match the user */
                        if (hostok)
                                userok = !(strcmp(ruser,*user ? user : luser));
                        break;
                }
                if (hostok && userok)
                        return(0);
        }
        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);
}
#endif
#endif