/*      $NetBSD: mount_umap.c,v 1.27 2020/07/26 08:20:23 mlelstv Exp $  */

/*
 * Copyright (c) 1992, 1993, 1994
 *      The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software donated to Berkeley by
 * Jan-Simon Pendry.
 *
 * 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 <sys/cdefs.h>
#ifndef lint
__COPYRIGHT("@(#) Copyright (c) 1992, 1993, 1994\
 The Regents of the University of California.  All rights reserved.");
#endif /* not lint */

#ifndef lint
#if 0
static char sccsid[] = "@(#)mount_umap.c        8.5 (Berkeley) 4/26/95";
#else
__RCSID("$NetBSD: mount_umap.c,v 1.27 2020/07/26 08:20:23 mlelstv Exp $");
#endif
#endif /* not lint */

#include <sys/param.h>
#include <sys/mount.h>
#include <sys/stat.h>

#include <miscfs/umapfs/umap.h>

#include <err.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include <mntopts.h>

#include "mountprog.h"

#define ROOTUSER 0
/*
 * This define controls whether any user but the superuser can own and
 * write mapfiles.  If other users can, system security can be gravely
 * compromised.  If this is not a concern, undefine SECURITY.
 */
#define MAPSECURITY 1

/*
 * This routine provides the user interface to mounting a umap layer.
 * It takes 4 mandatory parameters.  The mandatory arguments are the place 
 * where the next lower level is mounted, the place where the umap layer is to
 * be mounted, the name of the user mapfile, and the name of the group
 * mapfile.  The routine checks the ownerships and permissions on the
 * mapfiles, then opens and reads them.  Then it calls mount(), which
 * will, in turn, call the umap version of mount. 
 */

static const struct mntopt mopts[] = {
        MOPT_STDOPTS,
        MOPT_NULL,
};

int     mount_umap(int argc, char **argv);
__dead static void      usage(void);

#ifndef MOUNT_NOMAIN
int
main(int argc, char **argv)
{
        return mount_umap(argc, argv);
}
#endif

int
mount_umap(int argc, char *argv[])
{
        static char not[] = "; not mounted.";
        struct stat statbuf;
        struct umap_args args;
        FILE *fp, *gfp;
        long d1, d2;
        u_long mapdata[MAPFILEENTRIES][2];
        u_long gmapdata[GMAPFILEENTRIES][2];
        u_long fsid;
        int ch, count, gnentries, mntflags, nentries;
        char *gmapfile, *mapfile, buf[20];
        char source[MAXPATHLEN], target[MAXPATHLEN];
        mntoptparse_t mp;

        fsid = mntflags = 0;
        mapfile = gmapfile = NULL;
        while ((ch = getopt(argc, argv, "g:i:o:u:")) != -1)
                switch (ch) {
                case 'g':
                        gmapfile = optarg;
                        break;
                case 'i':
                        fsid = strtoul(optarg, NULL, 16);
                        break;
                case 'o':
                        mp = getmntopts(optarg, mopts, &mntflags, 0);
                        if (mp == NULL)
                                err(1, "getmntopts");
                        freemntopts(mp);
                        break;
                case 'u':
                        mapfile = optarg;
                        break;
                case '?':
                default:
                        usage();
                }
        argc -= optind;
        argv += optind;

        if (argc != 2 || mapfile == NULL || gmapfile == NULL)
                usage();

        pathadj(argv[0], source);
        pathadj(argv[1], target);

        /* Read in uid mapping data. */
        if ((fp = fopen(mapfile, "r")) == NULL)
                err(1, "%s%s", mapfile, not);

#ifdef MAPSECURITY
        /*
         * Check that group and other don't have write permissions on
         * this mapfile, and that the mapfile belongs to root. 
         */
        if (fstat(fileno(fp), &statbuf))
                err(1, "%s%s", mapfile, not);
        if (statbuf.st_mode & S_IWGRP || statbuf.st_mode & S_IWOTH) {
                strmode(statbuf.st_mode, buf);
                err(1, "%s: improper write permissions (%s)%s",
                    mapfile, buf, not);
        }
        if (statbuf.st_uid != ROOTUSER)
                errx(1, "%s does not belong to root%s", mapfile, not);
#endif /* MAPSECURITY */

        if ((fscanf(fp, "%d\n", &nentries)) != 1)
                errx(1, "%s: nentries not found%s", mapfile, not);
        if (nentries > MAPFILEENTRIES)
                errx(1,
                    "maximum number of entries is %d%s", MAPFILEENTRIES, not);
#if 0
        (void)printf("reading %d entries\n", nentries);
#endif
        for (count = 0; count < nentries; ++count) {
                if ((fscanf(fp, "%lu %lu\n", &d1, &d2)) != 2) {
                        if (ferror(fp))
                                err(1, "%s%s", mapfile, not);
                        if (feof(fp))
                                errx(1, "%s: unexpected end-of-file%s",
                                    mapfile, not);
                        errx(1, "%s: illegal format (line %d)%s",
                            mapfile, count + 2, not);
                }
                mapdata[count][0] = d1;
                mapdata[count][1] = d2;
#if 0
                /* Fix a security hole. */
                if (mapdata[count][1] == 0)
                        errx(1, "mapping id 0 not permitted (line %d)%s",
                            count + 2, not);
#endif
        }

        /* Read in gid mapping data. */
        if ((gfp = fopen(gmapfile, "r")) == NULL)
                err(1, "%s%s", gmapfile, not);

#ifdef MAPSECURITY
        /*
         * Check that group and other don't have write permissions on
         * this group mapfile, and that the file belongs to root. 
         */
        if (fstat(fileno(gfp), &statbuf))
                err(1, "%s%s", gmapfile, not);
        if (statbuf.st_mode & S_IWGRP || statbuf.st_mode & S_IWOTH) {
                strmode(statbuf.st_mode, buf);
                err(1, "%s: improper write permissions (%s)%s",
                    gmapfile, buf, not);
        }
        if (statbuf.st_uid != ROOTUSER)
                errx(1, "%s does not belong to root%s", gmapfile, not);
#endif /* MAPSECURITY */

        if ((fscanf(gfp, "%d\n", &gnentries)) != 1)
                errx(1, "nentries not found%s", not);
        if (gnentries > MAPFILEENTRIES)
                errx(1,
                    "maximum number of entries is %d%s", GMAPFILEENTRIES, not);
#if 0
        (void)printf("reading %d group entries\n", gnentries);
#endif

        for (count = 0; count < gnentries; ++count) {
                if ((fscanf(gfp, "%lu %lu\n",
                    &(gmapdata[count][0]), &(gmapdata[count][1]))) != 2) {
                        if (ferror(gfp))
                                err(1, "%s%s", gmapfile, not);
                        if (feof(gfp))
                                errx(1, "%s: unexpected end-of-file%s",
                                    gmapfile, not);
                        errx(1, "%s: illegal format (line %d)%s",
                            gmapfile, count + 2, not);
                }
        }


        /* Setup mount call args. */
        args.la.target = source;
        args.nentries = nentries;
        args.mapdata = mapdata;
        args.gnentries = gnentries;
        args.gmapdata = gmapdata;
        args.fsid = fsid;

        if (mount(MOUNT_UMAP, target, mntflags, &args, sizeof args) == -1)
                err(1, "%s on %s", source, target);
        if (mntflags & MNT_GETARGS) {
                printf("nentries=%d, gnentries=%d\n", args.nentries,
                    args.gnentries);
        }
        exit(0);
}

static void
usage(void)
{
        (void)fprintf(stderr,
"usage: mount_umap [-i fsid] [-o options] -g groupmap -u usermap target_fs mount_point\n");
        exit(1);
}