lib/roken/iruserok.c

   1 /*
   2  * Copyright (c) 1983, 1993, 1994
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. Neither the name of the University nor the names of its contributors
  14  *    may be used to endorse or promote products derived from this software
  15  *    without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  */
  29
  30 #include <config.h>
  31
  32 #include <stdio.h>
  33 #include <ctype.h>
  34 #ifdef HAVE_SYS_TYPES_H
  35 #include <sys/types.h>
  36 #endif
  37 #ifdef HAVE_NETINET_IN_H
  38 #include <netinet/in.h>
  39 #endif
  40 #ifdef HAVE_NETINET_IN6_H
  41 #include <netinet/in6.h>
  42 #endif
  43 #ifdef HAVE_NETINET6_IN6_H
  44 #include <netinet6/in6.h>
  45 #endif
  46 #ifdef HAVE_RPCSVC_YPCLNT_H
  47 #include <rpcsvc/ypclnt.h>
  48 #endif
  49
  50 #include "roken.h"
  51
  52 int     __check_rhosts_file = 1;
  53 char    *__rcmd_errstr = 0;
  54
  55 /*
  56  * Returns "true" if match, 0 if no match.
  57  */
  58 static
  59 int
  60 __icheckhost(unsigned raddr, const char *lhost)
  61 {
  62         struct hostent *hp;
  63         u_long laddr;
  64         char **pp;
  65
  66         /* Try for raw ip address first. */
  67         if (isdigit((unsigned char)*lhost)
  68             && (long)(laddr = inet_addr(lhost)) != -1)
  69                 return (raddr == laddr);
  70
  71         /* Better be a hostname. */
  72         if ((hp = gethostbyname(lhost)) == NULL)
  73                 return (0);
  74
  75         /* Spin through ip addresses. */
  76         for (pp = hp->h_addr_list; *pp; ++pp)
  77                 if (memcmp(&raddr, *pp, sizeof(u_long)) == 0)
  78                         return (1);
  79
  80         /* No match. */
  81         return (0);
  82 }
  83
  84 /*
  85  * Returns 0 if ok, -1 if not ok.
  86  */
  87 static
  88 int
  89 __ivaliduser(FILE *hostf, unsigned raddr, const char *luser,
  90              const char *ruser)
  91 {
  92         char *user, *p;
  93         int ch;
  94         char buf[MaxHostNameLen + 128];         /* host + login */
  95         char hname[MaxHostNameLen];
  96         struct hostent *hp;
  97         /* Presumed guilty until proven innocent. */
  98         int userok = 0, hostok = 0;
  99 #ifdef HAVE_YP_GET_DEFAULT_DOMAIN
 100         char *ypdomain;
 101
 102         if (yp_get_default_domain(&ypdomain))
 103                 ypdomain = NULL;
 104 #else
 105 #define ypdomain NULL
 106 #endif
 107         /* We need to get the damn hostname back for netgroup matching. */
 108         if ((hp = gethostbyaddr((char *)&raddr,
 109                                 sizeof(u_long),
 110                                 AF_INET)) == NULL)
 111                 return (-1);
 112         strlcpy(hname, hp->h_name, sizeof(hname));
 113
 114         while (fgets(buf, sizeof(buf), hostf)) {
 115                 p = buf;
 116                 /* Skip lines that are too long. */
 117                 if (strchr(p, '\n') == NULL) {
 118                         while ((ch = getc(hostf)) != '\n' && ch != EOF);
 119                         continue;
 120                 }
 121                 if (*p == '\n' || *p == '#') {
 122                         /* comment... */
 123                         continue;
 124                 }
 125                 while (*p != '\n' && *p != ' ' && *p != '\t' && *p != '\0') {
 126                         if (isupper((unsigned char)*p))
 127                             *p = tolower((unsigned char)*p);
 128                         p++;
 129                 }
 130                 if (*p == ' ' || *p == '\t') {
 131                         *p++ = '\0';
 132                         while (*p == ' ' || *p == '\t')
 133                                 p++;
 134                         user = p;
 135                         while (*p != '\n' && *p != ' ' &&
 136                             *p != '\t' && *p != '\0')
 137                                 p++;
 138                 } else
 139                         user = p;
 140                 *p = '\0';
 141                 /*
 142                  * Do +/- and +@/-@ checking. This looks really nasty,
 143                  * but it matches SunOS's behavior so far as I can tell.
 144                  */
 145                 switch(buf[0]) {
 146                 case '+':
 147                         if (!buf[1]) {     /* '+' matches all hosts */
 148                                 hostok = 1;
 149                                 break;
 150                         }
 151                         if (buf[1] == '@')  /* match a host by netgroup */
 152                                 hostok = innetgr((char *)&buf[2],
 153                                         (char *)&hname, NULL, ypdomain);
 154                         else            /* match a host by addr */
 155                                 hostok = __icheckhost(raddr,(char *)&buf[1]);
 156                         break;
 157                 case '-':     /* reject '-' hosts and all their users */
 158                         if (buf[1] == '@') {
 159                                 if (innetgr((char *)&buf[2],
 160                                               (char *)&hname, NULL, ypdomain))
 161                                         return(-1);
 162                         } else {
 163                                 if (__icheckhost(raddr,(char *)&buf[1]))
 164                                         return(-1);
 165                         }
 166                         break;
 167                 default:  /* if no '+' or '-', do a simple match */
 168                         hostok = __icheckhost(raddr, buf);
 169                         break;
 170                 }
 171                 switch(*user) {
 172                 case '+':
 173                         if (!*(user+1)) {      /* '+' matches all users */
 174                                 userok = 1;
 175                                 break;
 176                         }
 177                         if (*(user+1) == '@')  /* match a user by netgroup */
 178                                 userok = innetgr(user+2, NULL, (char *)ruser,
 179                                                  ypdomain);
 180                         else       /* match a user by direct specification */
 181                                 userok = !(strcmp(ruser, user+1));
 182                         break;
 183                 case '-':               /* if we matched a hostname, */
 184                         if (hostok) {   /* check for user field rejections */
 185                                 if (!*(user+1))
 186                                         return(-1);
 187                                 if (*(user+1) == '@') {
 188                                         if (innetgr(user+2, NULL,
 189                                                     (char *)ruser, ypdomain))
 190                                                 return(-1);
 191                                 } else {
 192                                         if (!strcmp(ruser, user+1))
 193                                                 return(-1);
 194                                 }
 195                         }
 196                         break;
 197                 default:        /* no rejections: try to match the user */
 198                         if (hostok)
 199                                 userok = !(strcmp(ruser,*user ? user : luser));
 200                         break;
 201                 }
 202                 if (hostok && userok)
 203                         return(0);
 204         }
 205         return (-1);
 206 }
 207
 208 /*
 209  * New .rhosts strategy: We are passed an ip address. We spin through
 210  * hosts.equiv and .rhosts looking for a match. When the .rhosts only
 211  * has ip addresses, we don't have to trust a nameserver.  When it
 212  * contains hostnames, we spin through the list of addresses the nameserver
 213  * gives us and look for a match.
 214  *
 215  * Returns 0 if ok, -1 if not ok.
 216  */
 217 int ROKEN_LIB_FUNCTION
 218 iruserok(unsigned raddr, int superuser, const char *ruser, const char *luser)
 219 {
 220         char *cp;
 221         struct stat sbuf;
 222         struct passwd *pwd;
 223         FILE *hostf;
 224         uid_t uid;
 225         int first;
 226         char pbuf[MaxPathLen];
 227
 228         first = 1;
 229         hostf = superuser ? NULL : fopen(_PATH_HEQUIV, "r");
 230 again:
 231         if (hostf) {
 232                 if (__ivaliduser(hostf, raddr, luser, ruser) == 0) {
 233                         fclose(hostf);
 234                         return (0);
 235                 }
 236                 fclose(hostf);
 237         }
 238         if (first == 1 && (__check_rhosts_file || superuser)) {
 239                 first = 0;
 240                 if ((pwd = k_getpwnam((char*)luser)) == NULL)
 241                         return (-1);
 242                 snprintf (pbuf, sizeof(pbuf), "%s/.rhosts", pwd->pw_dir);
 243
 244                 /*
 245                  * Change effective uid while opening .rhosts.  If root and
 246                  * reading an NFS mounted file system, can't read files that
 247                  * are protected read/write owner only.
 248                  */
 249                 uid = geteuid();
 250                 if (seteuid(pwd->pw_uid) < 0)
 251                         return (-1);
 252                 hostf = fopen(pbuf, "r");
 253                 seteuid(uid);
 254
 255                 if (hostf == NULL)
 256                         return (-1);
 257                 /*
 258                  * If not a regular file, or is owned by someone other than
 259                  * user or root or if writeable by anyone but the owner, quit.
 260                  */
 261                 cp = NULL;
 262                 if (lstat(pbuf, &sbuf) < 0)
 263                         cp = ".rhosts lstat failed";
 264                 else if (!S_ISREG(sbuf.st_mode))
 265                         cp = ".rhosts not regular file";
 266                 else if (fstat(fileno(hostf), &sbuf) < 0)
 267                         cp = ".rhosts fstat failed";
 268                 else if (sbuf.st_uid && sbuf.st_uid != pwd->pw_uid)
 269                         cp = "bad .rhosts owner";
 270                 else if (sbuf.st_mode & (S_IWGRP|S_IWOTH))
 271                         cp = ".rhosts writeable by other than owner";
 272                 /* If there were any problems, quit. */
 273                 if (cp) {
 274                         __rcmd_errstr = cp;
 275                         fclose(hostf);
 276                         return (-1);
 277                 }
 278                 goto again;
 279         }
 280         return (-1);
 281 }