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 #ifdef HAVE_CONFIG_H
  31 #include <config.h>
  32 RCSID("$Id$");
  33 #endif
  34
  35 #include <stdio.h>
  36 #include <ctype.h>
  37 #ifdef HAVE_SYS_TYPES_H
  38 #include <sys/types.h>
  39 #endif
  40 #ifdef HAVE_NETINET_IN_H
  41 #include <netinet/in.h>
  42 #endif
  43 #ifdef HAVE_NETINET_IN6_H
  44 #include <netinet/in6.h>
  45 #endif
  46 #ifdef HAVE_NETINET6_IN6_H
  47 #include <netinet6/in6.h>
  48 #endif
  49 #ifdef HAVE_RPCSVC_YPCLNT_H
  50 #include <rpcsvc/ypclnt.h>
  51 #endif
  52
  53 #include "roken.h"
  54
  55 int     __check_rhosts_file = 1;
  56 char    *__rcmd_errstr = 0;
  57
  58 /*
  59  * Returns "true" if match, 0 if no match.
  60  */
  61 static
  62 int
  63 __icheckhost(unsigned raddr, const char *lhost)
  64 {
  65         struct hostent *hp;
  66         u_long laddr;
  67         char **pp;
  68
  69         /* Try for raw ip address first. */
  70         if (isdigit((unsigned char)*lhost)
  71             && (long)(laddr = inet_addr(lhost)) != -1)
  72                 return (raddr == laddr);
  73
  74         /* Better be a hostname. */
  75         if ((hp = gethostbyname(lhost)) == NULL)
  76                 return (0);
  77
  78         /* Spin through ip addresses. */
  79         for (pp = hp->h_addr_list; *pp; ++pp)
  80                 if (memcmp(&raddr, *pp, sizeof(u_long)) == 0)
  81                         return (1);
  82
  83         /* No match. */
  84         return (0);
  85 }
  86
  87 /*
  88  * Returns 0 if ok, -1 if not ok.
  89  */
  90 static
  91 int
  92 __ivaliduser(FILE *hostf, unsigned raddr, const char *luser,
  93              const char *ruser)
  94 {
  95         char *user, *p;
  96         int ch;
  97         char buf[MaxHostNameLen + 128];         /* host + login */
  98         char hname[MaxHostNameLen];
  99         struct hostent *hp;
 100         /* Presumed guilty until proven innocent. */
 101         int userok = 0, hostok = 0;
 102 #ifdef HAVE_YP_GET_DEFAULT_DOMAIN
 103         char *ypdomain;
 104
 105         if (yp_get_default_domain(&ypdomain))
 106                 ypdomain = NULL;
 107 #else
 108 #define ypdomain NULL
 109 #endif
 110         /* We need to get the damn hostname back for netgroup matching. */
 111         if ((hp = gethostbyaddr((char *)&raddr,
 112                                 sizeof(u_long),
 113                                 AF_INET)) == NULL)
 114                 return (-1);
 115         strlcpy(hname, hp->h_name, sizeof(hname));
 116
 117         while (fgets(buf, sizeof(buf), hostf)) {
 118                 p = buf;
 119                 /* Skip lines that are too long. */
 120                 if (strchr(p, '\n') == NULL) {
 121                         while ((ch = getc(hostf)) != '\n' && ch != EOF);
 122                         continue;
 123                 }
 124                 if (*p == '\n' || *p == '#') {
 125                         /* comment... */
 126                         continue;
 127                 }
 128                 while (*p != '\n' && *p != ' ' && *p != '\t' && *p != '\0') {
 129                         if (isupper((unsigned char)*p))
 130                             *p = tolower((unsigned char)*p);
 131                         p++;
 132                 }
 133                 if (*p == ' ' || *p == '\t') {
 134                         *p++ = '\0';
 135                         while (*p == ' ' || *p == '\t')
 136                                 p++;
 137                         user = p;
 138                         while (*p != '\n' && *p != ' ' &&
 139                             *p != '\t' && *p != '\0')
 140                                 p++;
 141                 } else
 142                         user = p;
 143                 *p = '\0';
 144                 /*
 145                  * Do +/- and +@/-@ checking. This looks really nasty,
 146                  * but it matches SunOS's behavior so far as I can tell.
 147                  */
 148                 switch(buf[0]) {
 149                 case '+':
 150                         if (!buf[1]) {     /* '+' matches all hosts */
 151                                 hostok = 1;
 152                                 break;
 153                         }
 154                         if (buf[1] == '@')  /* match a host by netgroup */
 155                                 hostok = innetgr((char *)&buf[2],
 156                                         (char *)&hname, NULL, ypdomain);
 157                         else            /* match a host by addr */
 158                                 hostok = __icheckhost(raddr,(char *)&buf[1]);
 159                         break;
 160                 case '-':     /* reject '-' hosts and all their users */
 161                         if (buf[1] == '@') {
 162                                 if (innetgr((char *)&buf[2],
 163                                               (char *)&hname, NULL, ypdomain))
 164                                         return(-1);
 165                         } else {
 166                                 if (__icheckhost(raddr,(char *)&buf[1]))
 167                                         return(-1);
 168                         }
 169                         break;
 170                 default:  /* if no '+' or '-', do a simple match */
 171                         hostok = __icheckhost(raddr, buf);
 172                         break;
 173                 }
 174                 switch(*user) {
 175                 case '+':
 176                         if (!*(user+1)) {      /* '+' matches all users */
 177                                 userok = 1;
 178                                 break;
 179                         }
 180                         if (*(user+1) == '@')  /* match a user by netgroup */
 181                                 userok = innetgr(user+2, NULL, (char *)ruser,
 182                                                  ypdomain);
 183                         else       /* match a user by direct specification */
 184                                 userok = !(strcmp(ruser, user+1));
 185                         break;
 186                 case '-':               /* if we matched a hostname, */
 187                         if (hostok) {   /* check for user field rejections */
 188                                 if (!*(user+1))
 189                                         return(-1);
 190                                 if (*(user+1) == '@') {
 191                                         if (innetgr(user+2, NULL,
 192                                                     (char *)ruser, ypdomain))
 193                                                 return(-1);
 194                                 } else {
 195                                         if (!strcmp(ruser, user+1))
 196                                                 return(-1);
 197                                 }
 198                         }
 199                         break;
 200                 default:        /* no rejections: try to match the user */
 201                         if (hostok)
 202                                 userok = !(strcmp(ruser,*user ? user : luser));
 203                         break;
 204                 }
 205                 if (hostok && userok)
 206                         return(0);
 207         }
 208         return (-1);
 209 }
 210
 211 /*
 212  * New .rhosts strategy: We are passed an ip address. We spin through
 213  * hosts.equiv and .rhosts looking for a match. When the .rhosts only
 214  * has ip addresses, we don't have to trust a nameserver.  When it
 215  * contains hostnames, we spin through the list of addresses the nameserver
 216  * gives us and look for a match.
 217  *
 218  * Returns 0 if ok, -1 if not ok.
 219  */
 220 int ROKEN_LIB_FUNCTION
 221 iruserok(unsigned raddr, int superuser, const char *ruser, const char *luser)
 222 {
 223         char *cp;
 224         struct stat sbuf;
 225         struct passwd *pwd;
 226         FILE *hostf;
 227         uid_t uid;
 228         int first;
 229         char pbuf[MaxPathLen];
 230
 231         first = 1;
 232         hostf = superuser ? NULL : fopen(_PATH_HEQUIV, "r");
 233 again:
 234         if (hostf) {
 235                 if (__ivaliduser(hostf, raddr, luser, ruser) == 0) {
 236                         fclose(hostf);
 237                         return (0);
 238                 }
 239                 fclose(hostf);
 240         }
 241         if (first == 1 && (__check_rhosts_file || superuser)) {
 242                 first = 0;
 243                 if ((pwd = k_getpwnam((char*)luser)) == NULL)
 244                         return (-1);
 245                 snprintf (pbuf, sizeof(pbuf), "%s/.rhosts", pwd->pw_dir);
 246
 247                 /*
 248                  * Change effective uid while opening .rhosts.  If root and
 249                  * reading an NFS mounted file system, can't read files that
 250                  * are protected read/write owner only.
 251                  */
 252                 uid = geteuid();
 253                 if (seteuid(pwd->pw_uid) < 0)
 254                         return (-1);
 255                 hostf = fopen(pbuf, "r");
 256                 seteuid(uid);
 257
 258                 if (hostf == NULL)
 259                         return (-1);
 260                 /*
 261                  * If not a regular file, or is owned by someone other than
 262                  * user or root or if writeable by anyone but the owner, quit.
 263                  */
 264                 cp = NULL;
 265                 if (lstat(pbuf, &sbuf) < 0)
 266                         cp = ".rhosts lstat failed";
 267                 else if (!S_ISREG(sbuf.st_mode))
 268                         cp = ".rhosts not regular file";
 269                 else if (fstat(fileno(hostf), &sbuf) < 0)
 270                         cp = ".rhosts fstat failed";
 271                 else if (sbuf.st_uid && sbuf.st_uid != pwd->pw_uid)
 272                         cp = "bad .rhosts owner";
 273                 else if (sbuf.st_mode & (S_IWGRP|S_IWOTH))
 274                         cp = ".rhosts writeable by other than owner";
 275                 /* If there were any problems, quit. */
 276                 if (cp) {
 277                         __rcmd_errstr = cp;
 278                         fclose(hostf);
 279                         return (-1);
 280                 }
 281                 goto again;
 282         }
 283         return (-1);
 284 }