crypto/external/bsd/heimdal/dist/lib/roken/iruserok.c

   1 /*      $NetBSD: iruserok.c,v 1.1.1.1 2011/04/13 18:15:42 elric Exp $   */
   2
   3 /*
   4  * Copyright (c) 1983, 1993, 1994
   5  *      The Regents of the University of California.  All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  * 3. Neither the name of the University nor the names of its contributors
  16  *    may be used to endorse or promote products derived from this software
  17  *    without specific prior written permission.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  29  * SUCH DAMAGE.
  30  */
  31
  32 #include <config.h>
  33
  34 #include <stdio.h>
  35 #include <ctype.h>
  36 #ifdef HAVE_SYS_TYPES_H
  37 #include <sys/types.h>
  38 #endif
  39 #ifdef HAVE_NETINET_IN_H
  40 #include <netinet/in.h>
  41 #endif
  42 #ifdef HAVE_NETINET_IN6_H
  43 #include <netinet/in6.h>
  44 #endif
  45 #ifdef HAVE_NETINET6_IN6_H
  46 #include <netinet6/in6.h>
  47 #endif
  48 #ifdef HAVE_RPCSVC_YPCLNT_H
  49 #include <rpcsvc/ypclnt.h>
  50 #endif
  51
  52 #include <krb5/roken.h>
  53
  54 int     __check_rhosts_file = 1;
  55 char    *__rcmd_errstr = 0;
  56
  57 /*
  58  * Returns "true" if match, 0 if no match.
  59  */
  60 static
  61 int
  62 __icheckhost(unsigned raddr, const char *lhost)
  63 {
  64         struct hostent *hp;
  65         u_long laddr;
  66         char **pp;
  67
  68         /* Try for raw ip address first. */
  69         if (isdigit((unsigned char)*lhost)
  70             && (long)(laddr = inet_addr(lhost)) != -1)
  71                 return (raddr == laddr);
  72
  73         /* Better be a hostname. */
  74         if ((hp = gethostbyname(lhost)) == NULL)
  75                 return (0);
  76
  77         /* Spin through ip addresses. */
  78         for (pp = hp->h_addr_list; *pp; ++pp)
  79                 if (memcmp(&raddr, *pp, sizeof(u_long)) == 0)
  80                         return (1);
  81
  82         /* No match. */
  83         return (0);
  84 }
  85
  86 /*
  87  * Returns 0 if ok, -1 if not ok.
  88  */
  89 static
  90 int
  91 __ivaliduser(FILE *hostf, unsigned raddr, const char *luser,
  92              const char *ruser)
  93 {
  94         char *user, *p;
  95         int ch;
  96         char buf[MaxHostNameLen + 128];         /* host + login */
  97         char hname[MaxHostNameLen];
  98         struct hostent *hp;
  99         /* Presumed guilty until proven innocent. */
 100         int userok = 0, hostok = 0;
 101 #ifdef HAVE_YP_GET_DEFAULT_DOMAIN
 102         char *ypdomain;
 103
 104         if (yp_get_default_domain(&ypdomain))
 105                 ypdomain = NULL;
 106 #else
 107 #define ypdomain NULL
 108 #endif
 109         /* We need to get the damn hostname back for netgroup matching. */
 110         if ((hp = gethostbyaddr((char *)&raddr,
 111                                 sizeof(u_long),
 112                                 AF_INET)) == NULL)
 113                 return (-1);
 114         strlcpy(hname, hp->h_name, sizeof(hname));
 115
 116         while (fgets(buf, sizeof(buf), hostf)) {
 117                 p = buf;
 118                 /* Skip lines that are too long. */
 119                 if (strchr(p, '\n') == NULL) {
 120                         while ((ch = getc(hostf)) != '\n' && ch != EOF);
 121                         continue;
 122                 }
 123                 if (*p == '\n' || *p == '#') {
 124                         /* comment... */
 125                         continue;
 126                 }
 127                 while (*p != '\n' && *p != ' ' && *p != '\t' && *p != '\0') {
 128                         if (isupper((unsigned char)*p))
 129                             *p = tolower((unsigned char)*p);
 130                         p++;
 131                 }
 132                 if (*p == ' ' || *p == '\t') {
 133                         *p++ = '\0';
 134                         while (*p == ' ' || *p == '\t')
 135                                 p++;
 136                         user = p;
 137                         while (*p != '\n' && *p != ' ' &&
 138                             *p != '\t' && *p != '\0')
 139                                 p++;
 140                 } else
 141                         user = p;
 142                 *p = '\0';
 143                 /*
 144                  * Do +/- and +@/-@ checking. This looks really nasty,
 145                  * but it matches SunOS's behavior so far as I can tell.
 146                  */
 147                 switch(buf[0]) {
 148                 case '+':
 149                         if (!buf[1]) {     /* '+' matches all hosts */
 150                                 hostok = 1;
 151                                 break;
 152                         }
 153                         if (buf[1] == '@')  /* match a host by netgroup */
 154                                 hostok = innetgr((char *)&buf[2],
 155                                         (char *)&hname, NULL, ypdomain);
 156                         else            /* match a host by addr */
 157                                 hostok = __icheckhost(raddr,(char *)&buf[1]);
 158                         break;
 159                 case '-':     /* reject '-' hosts and all their users */
 160                         if (buf[1] == '@') {
 161                                 if (innetgr((char *)&buf[2],
 162                                               (char *)&hname, NULL, ypdomain))
 163                                         return(-1);
 164                         } else {
 165                                 if (__icheckhost(raddr,(char *)&buf[1]))
 166                                         return(-1);
 167                         }
 168                         break;
 169                 default:  /* if no '+' or '-', do a simple match */
 170                         hostok = __icheckhost(raddr, buf);
 171                         break;
 172                 }
 173                 switch(*user) {
 174                 case '+':
 175                         if (!*(user+1)) {      /* '+' matches all users */
 176                                 userok = 1;
 177                                 break;
 178                         }
 179                         if (*(user+1) == '@')  /* match a user by netgroup */
 180                                 userok = innetgr(user+2, NULL, (char *)ruser,
 181                                                  ypdomain);
 182                         else       /* match a user by direct specification */
 183                                 userok = !(strcmp(ruser, user+1));
 184                         break;
 185                 case '-':               /* if we matched a hostname, */
 186                         if (hostok) {   /* check for user field rejections */
 187                                 if (!*(user+1))
 188                                         return(-1);
 189                                 if (*(user+1) == '@') {
 190                                         if (innetgr(user+2, NULL,
 191                                                     (char *)ruser, ypdomain))
 192                                                 return(-1);
 193                                 } else {
 194                                         if (!strcmp(ruser, user+1))
 195                                                 return(-1);
 196                                 }
 197                         }
 198                         break;
 199                 default:        /* no rejections: try to match the user */
 200                         if (hostok)
 201                                 userok = !(strcmp(ruser,*user ? user : luser));
 202                         break;
 203                 }
 204                 if (hostok && userok)
 205                         return(0);
 206         }
 207         return (-1);
 208 }
 209
 210 /*
 211  * New .rhosts strategy: We are passed an ip address. We spin through
 212  * hosts.equiv and .rhosts looking for a match. When the .rhosts only
 213  * has ip addresses, we don't have to trust a nameserver.  When it
 214  * contains hostnames, we spin through the list of addresses the nameserver
 215  * gives us and look for a match.
 216  *
 217  * Returns 0 if ok, -1 if not ok.
 218  */
 219 ROKEN_LIB_FUNCTION int ROKEN_LIB_CALL
 220 iruserok(unsigned raddr, int superuser, const char *ruser, const char *luser)
 221 {
 222         char *cp;
 223         struct stat sbuf;
 224         struct passwd *pwd;
 225         FILE *hostf;
 226         uid_t uid;
 227         int first;
 228         char pbuf[MaxPathLen];
 229
 230         first = 1;
 231         hostf = superuser ? NULL : fopen(_PATH_HEQUIV, "r");
 232 again:
 233         if (hostf) {
 234                 if (__ivaliduser(hostf, raddr, luser, ruser) == 0) {
 235                         fclose(hostf);
 236                         return (0);
 237                 }
 238                 fclose(hostf);
 239         }
 240         if (first == 1 && (__check_rhosts_file || superuser)) {
 241                 first = 0;
 242                 if ((pwd = k_getpwnam((char*)luser)) == NULL)
 243                         return (-1);
 244                 snprintf (pbuf, sizeof(pbuf), "%s/.rhosts", pwd->pw_dir);
 245
 246                 /*
 247                  * Change effective uid while opening .rhosts.  If root and
 248                  * reading an NFS mounted file system, can't read files that
 249                  * are protected read/write owner only.
 250                  */
 251                 uid = geteuid();
 252                 if (seteuid(pwd->pw_uid) < 0)
 253                         return (-1);
 254                 hostf = fopen(pbuf, "r");
 255                 seteuid(uid);
 256
 257                 if (hostf == NULL)
 258                         return (-1);
 259                 /*
 260                  * If not a regular file, or is owned by someone other than
 261                  * user or root or if writeable by anyone but the owner, quit.
 262                  */
 263                 cp = NULL;
 264                 if (lstat(pbuf, &sbuf) < 0)
 265                         cp = ".rhosts lstat failed";
 266                 else if (!S_ISREG(sbuf.st_mode))
 267                         cp = ".rhosts not regular file";
 268                 else if (fstat(fileno(hostf), &sbuf) < 0)
 269                         cp = ".rhosts fstat failed";
 270                 else if (sbuf.st_uid && sbuf.st_uid != pwd->pw_uid)
 271                         cp = "bad .rhosts owner";
 272                 else if (sbuf.st_mode & (S_IWGRP|S_IWOTH))
 273                         cp = ".rhosts writeable by other than owner";
 274                 /* If there were any problems, quit. */
 275                 if (cp) {
 276                         __rcmd_errstr = cp;
 277                         fclose(hostf);
 278                         return (-1);
 279                 }
 280                 goto again;
 281         }
 282         return (-1);
 283 }