sbin/mount_umap/mount_umap.c

   1 /*      $NetBSD: mount_umap.c,v 1.21 2007/07/16 17:06:54 pooka Exp $    */
   2
   3 /*
   4  * Copyright (c) 1992, 1993, 1994
   5  *      The Regents of the University of California.  All rights reserved.
   6  *
   7  * This code is derived from software donated to Berkeley by
   8  * Jan-Simon Pendry.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  * 3. Neither the name of the University nor the names of its contributors
  19  *    may be used to endorse or promote products derived from this software
  20  *    without specific prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  */
  34
  35 #include <sys/cdefs.h>
  36 #ifndef lint
  37 __COPYRIGHT("@(#) Copyright (c) 1992, 1993, 1994\
  38  The Regents of the University of California.  All rights reserved.");
  39 #endif /* not lint */
  40
  41 #ifndef lint
  42 #if 0
  43 static char sccsid[] = "@(#)mount_umap.c        8.5 (Berkeley) 4/26/95";
  44 #else
  45 __RCSID("$NetBSD: mount_umap.c,v 1.21 2007/07/16 17:06:54 pooka Exp $");
  46 #endif
  47 #endif /* not lint */
  48
  49 #include <sys/param.h>
  50 #include <sys/mount.h>
  51 #include <sys/stat.h>
  52
  53 #include <miscfs/umapfs/umap.h>
  54
  55 #include <err.h>
  56 #include <stdio.h>
  57 #include <stdlib.h>
  58 #include <string.h>
  59 #include <unistd.h>
  60
  61 #include <mntopts.h>
  62
  63 #define ROOTUSER 0
  64 /*
  65  * This define controls whether any user but the superuser can own and
  66  * write mapfiles.  If other users can, system security can be gravely
  67  * compromised.  If this is not a concern, undefine SECURITY.
  68  */
  69 #define MAPSECURITY 1
  70
  71 /*
  72  * This routine provides the user interface to mounting a umap layer.
  73  * It takes 4 mandatory parameters.  The mandatory arguments are the place
  74  * where the next lower level is mounted, the place where the umap layer is to
  75  * be mounted, the name of the user mapfile, and the name of the group
  76  * mapfile.  The routine checks the ownerships and permissions on the
  77  * mapfiles, then opens and reads them.  Then it calls mount(), which
  78  * will, in turn, call the umap version of mount.
  79  */
  80
  81 static const struct mntopt mopts[] = {
  82         MOPT_STDOPTS,
  83         MOPT_NULL,
  84 };
  85
  86 int     mount_umap(int argc, char **argv);
  87 static void     usage(void);
  88
  89 #ifndef MOUNT_NOMAIN
  90 int
  91 main(int argc, char **argv)
  92 {
  93         return mount_umap(argc, argv);
  94 }
  95 #endif
  96
  97 int
  98 mount_umap(int argc, char *argv[])
  99 {
 100         static char not[] = "; not mounted.";
 101         struct stat statbuf;
 102         struct umap_args args;
 103         FILE *fp, *gfp;
 104         long d1, d2;
 105         u_long mapdata[MAPFILEENTRIES][2];
 106         u_long gmapdata[GMAPFILEENTRIES][2];
 107         int ch, count, gnentries, mntflags, nentries;
 108         char *gmapfile, *mapfile, buf[20];
 109         char source[MAXPATHLEN], target[MAXPATHLEN];
 110         mntoptparse_t mp;
 111
 112         mntflags = 0;
 113         mapfile = gmapfile = NULL;
 114         while ((ch = getopt(argc, argv, "g:o:u:")) != -1)
 115                 switch (ch) {
 116                 case 'g':
 117                         gmapfile = optarg;
 118                         break;
 119                 case 'o':
 120                         mp = getmntopts(optarg, mopts, &mntflags, 0);
 121                         if (mp == NULL)
 122                                 err(1, "getmntopts");
 123                         freemntopts(mp);
 124                         break;
 125                 case 'u':
 126                         mapfile = optarg;
 127                         break;
 128                 case '?':
 129                 default:
 130                         usage();
 131                 }
 132         argc -= optind;
 133         argv += optind;
 134
 135         if (argc != 2 || mapfile == NULL || gmapfile == NULL)
 136                 usage();
 137
 138         if (realpath(argv[0], source) == NULL)        /* Check source path */
 139                 err(1, "realpath %s", argv[0]);
 140         if (strncmp(argv[0], source, MAXPATHLEN)) {
 141                 warnx("\"%s\" is a relative path.", argv[0]);
 142                 warnx("using \"%s\" instead.", source);
 143         }
 144
 145         if (realpath(argv[1], target) == NULL)        /* Check mounton path */
 146                 err(1, "realpath %s", argv[1]);
 147         if (strncmp(argv[1], target, MAXPATHLEN)) {
 148                 warnx("\"%s\" is a relative path.", argv[1]);
 149                 warnx("using \"%s\" instead.", target);
 150         }
 151
 152         /* Read in uid mapping data. */
 153         if ((fp = fopen(mapfile, "r")) == NULL)
 154                 err(1, "%s%s", mapfile, not);
 155
 156 #ifdef MAPSECURITY
 157         /*
 158          * Check that group and other don't have write permissions on
 159          * this mapfile, and that the mapfile belongs to root.
 160          */
 161         if (fstat(fileno(fp), &statbuf))
 162                 err(1, "%s%s", mapfile, not);
 163         if (statbuf.st_mode & S_IWGRP || statbuf.st_mode & S_IWOTH) {
 164                 strmode(statbuf.st_mode, buf);
 165                 err(1, "%s: improper write permissions (%s)%s",
 166                     mapfile, buf, not);
 167         }
 168         if (statbuf.st_uid != ROOTUSER)
 169                 errx(1, "%s does not belong to root%s", mapfile, not);
 170 #endif /* MAPSECURITY */
 171
 172         if ((fscanf(fp, "%d\n", &nentries)) != 1)
 173                 errx(1, "%s: nentries not found%s", mapfile, not);
 174         if (nentries > MAPFILEENTRIES)
 175                 errx(1,
 176                     "maximum number of entries is %d%s", MAPFILEENTRIES, not);
 177 #if 0
 178         (void)printf("reading %d entries\n", nentries);
 179 #endif
 180         for (count = 0; count < nentries; ++count) {
 181                 if ((fscanf(fp, "%lu %lu\n", &d1, &d2)) != 2) {
 182                         if (ferror(fp))
 183                                 err(1, "%s%s", mapfile, not);
 184                         if (feof(fp))
 185                                 errx(1, "%s: unexpected end-of-file%s",
 186                                     mapfile, not);
 187                         errx(1, "%s: illegal format (line %d)%s",
 188                             mapfile, count + 2, not);
 189                 }
 190                 mapdata[count][0] = d1;
 191                 mapdata[count][1] = d2;
 192 #if 0
 193                 /* Fix a security hole. */
 194                 if (mapdata[count][1] == 0)
 195                         errx(1, "mapping id 0 not permitted (line %d)%s",
 196                             count + 2, not);
 197 #endif
 198         }
 199
 200         /* Read in gid mapping data. */
 201         if ((gfp = fopen(gmapfile, "r")) == NULL)
 202                 err(1, "%s%s", gmapfile, not);
 203
 204 #ifdef MAPSECURITY
 205         /*
 206          * Check that group and other don't have write permissions on
 207          * this group mapfile, and that the file belongs to root.
 208          */
 209         if (fstat(fileno(gfp), &statbuf))
 210                 err(1, "%s%s", gmapfile, not);
 211         if (statbuf.st_mode & S_IWGRP || statbuf.st_mode & S_IWOTH) {
 212                 strmode(statbuf.st_mode, buf);
 213                 err(1, "%s: improper write permissions (%s)%s",
 214                     gmapfile, buf, not);
 215         }
 216         if (statbuf.st_uid != ROOTUSER)
 217                 errx(1, "%s does not belong to root%s", gmapfile, not);
 218 #endif /* MAPSECURITY */
 219
 220         if ((fscanf(gfp, "%d\n", &gnentries)) != 1)
 221                 errx(1, "nentries not found%s", not);
 222         if (gnentries > MAPFILEENTRIES)
 223                 errx(1,
 224                     "maximum number of entries is %d%s", GMAPFILEENTRIES, not);
 225 #if 0
 226         (void)printf("reading %d group entries\n", gnentries);
 227 #endif
 228
 229         for (count = 0; count < gnentries; ++count) {
 230                 if ((fscanf(gfp, "%lu %lu\n",
 231                     &(gmapdata[count][0]), &(gmapdata[count][1]))) != 2) {
 232                         if (ferror(gfp))
 233                                 err(1, "%s%s", gmapfile, not);
 234                         if (feof(gfp))
 235                                 errx(1, "%s: unexpected end-of-file%s",
 236                                     gmapfile, not);
 237                         errx(1, "%s: illegal format (line %d)%s",
 238                             gmapfile, count + 2, not);
 239                 }
 240         }
 241
 242
 243         /* Setup mount call args. */
 244         args.la.target = source;
 245         args.nentries = nentries;
 246         args.mapdata = mapdata;
 247         args.gnentries = gnentries;
 248         args.gmapdata = gmapdata;
 249
 250         if (mount(MOUNT_UMAP, target, mntflags, &args, sizeof args) == -1)
 251                 err(1, "%s on %s", source, target);
 252         if (mntflags & MNT_GETARGS) {
 253                 printf("nentries=%d, gnentries=%d\n", args.nentries,
 254                     args.gnentries);
 255         }
 256         exit(0);
 257 }
 258
 259 static void
 260 usage(void)
 261 {
 262         (void)fprintf(stderr,
 263 "usage: mount_umap [-o options] -g groupmap -u usermap target_fs mount_point\n");
 264         exit(1);
 265 }