/*
 * 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. 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.
 */

#include <config.h>

#include <stdio.h>
#include <ctype.h>
#ifdef HAVE_SYS_TYPES_H
#include <sys/types.h>
#endif
#ifdef HAVE_NETINET_IN_H
#include <netinet/in.h>
#endif
#ifdef HAVE_NETINET_IN6_H
#include <netinet/in6.h>
#endif
#ifdef HAVE_NETINET6_IN6_H
#include <netinet6/in6.h>
#endif
#ifdef HAVE_RPCSVC_YPCLNT_H
#include <rpcsvc/ypclnt.h>
#endif

#include "roken.h"

int     __check_rhosts_file = 1;
char    *__rcmd_errstr = 0;

/*
 * Returns "true" if match, 0 if no match.
 */
static
int
__icheckhost(unsigned raddr, const char *lhost)
{
        struct hostent *hp;
        u_long laddr;
        char **pp;

        /* Try for raw ip address first. */
        if (isdigit((unsigned char)*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 (memcmp(&raddr, *pp, sizeof(u_long)) == 0)
                        return (1);

        /* No match. */
        return (0);
}

/*
 * Returns 0 if ok, -1 if not ok.
 */
static
int
__ivaliduser(FILE *hostf, unsigned raddr, const char *luser,
             const char *ruser)
{
        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 HAVE_YP_GET_DEFAULT_DOMAIN
        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);
        strlcpy(hname, hp->h_name, sizeof(hname));

        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') {
                        if (isupper((unsigned char)*p))
                            *p = tolower((unsigned char)*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, (char *)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,
                                                    (char *)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);
}

/*
 * 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.
 */
ROKEN_LIB_FUNCTION int ROKEN_LIB_CALL
iruserok(unsigned raddr, int superuser, const char *ruser, const char *luser)
{
        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) {
                        fclose(hostf);
                        return (0);
                }
                fclose(hostf);
        }
        if (first == 1 && (__check_rhosts_file || superuser)) {
                first = 0;
                if ((pwd = k_getpwnam((char*)luser)) == NULL)
                        return (-1);
                snprintf (pbuf, sizeof(pbuf), "%s/.rhosts", pwd->pw_dir);

                /*
                 * 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();
                if (seteuid(pwd->pw_uid) < 0)
                        return (-1);
                hostf = fopen(pbuf, "r");
                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;
                        fclose(hostf);
                        return (-1);
                }
                goto again;
        }
        return (-1);
}