freebsd-dev/sbin/mount_umapfs/mount_umapfs.c

236 lines
7.0 KiB
C

/*
* 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.
* 4. 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.
*/
#ifndef lint
static const char copyright[] =
"@(#) Copyright (c) 1992, 1993, 1994\n\
The Regents of the University of California. All rights reserved.\n";
#endif /* not lint */
#ifndef lint
#if 0
static char sccsid[] = "@(#)mount_umap.c 8.5 (Berkeley) 4/26/95";
#endif
static const char rcsid[] =
"$FreeBSD$";
#endif /* not lint */
#include <sys/param.h>
#include <sys/mount.h>
#include <sys/stat.h>
#include <fs/umapfs/umap.h>
#include <err.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sysexits.h>
#include <unistd.h>
#include "mntopts.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 struct mntopt mopts[] = {
MOPT_STDOPTS,
MOPT_END
};
static void usage(void) __dead2;
int
main(argc, argv)
int argc;
char *argv[];
{
static char not[] = "; not mounted";
struct stat statbuf;
struct umap_args args;
FILE *fp, *gfp;
u_long gmapdata[GMAPFILEENTRIES][2], mapdata[MAPFILEENTRIES][2];
int ch, count, gnentries, mntflags, nentries;
char *gmapfile, *mapfile, buf[20];
char source[MAXPATHLEN], target[MAXPATHLEN];
mntflags = 0;
mapfile = gmapfile = NULL;
while ((ch = getopt(argc, argv, "g:o:u:")) != -1)
switch (ch) {
case 'g':
gmapfile = optarg;
break;
case 'o':
getmntopts(optarg, mopts, &mntflags, 0);
break;
case 'u':
mapfile = optarg;
break;
case '?':
default:
usage();
}
argc -= optind;
argv += optind;
if (argc != 2 || mapfile == NULL || gmapfile == NULL)
usage();
/* resolve both target and source with realpath(3) */
(void)checkpath(argv[0], source);
(void)checkpath(argv[1], target);
/* Read in uid mapping data. */
if ((fp = fopen(mapfile, "r")) == NULL)
err(EX_NOINPUT, "%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(EX_OSERR, "%s%s", mapfile, not);
if (statbuf.st_mode & S_IWGRP || statbuf.st_mode & S_IWOTH) {
strmode(statbuf.st_mode, buf);
err(EX_NOPERM, "%s: improper write permissions (%s)%s",
mapfile, buf, not);
}
if (statbuf.st_uid != ROOTUSER)
errx(EX_NOPERM, "%s does not belong to root%s", mapfile, not);
#endif /* MAPSECURITY */
if ((fscanf(fp, "%d\n", &nentries)) != 1)
errx(EX_DATAERR, "%s: nentries not found%s", mapfile, not);
if (nentries > MAPFILEENTRIES)
errx(EX_DATAERR,
"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",
&(mapdata[count][0]), &(mapdata[count][1]))) != 2) {
if (ferror(fp))
err(EX_OSERR, "%s%s", mapfile, not);
if (feof(fp))
errx(EX_DATAERR, "%s: unexpected end-of-file%s",
mapfile, not);
errx(EX_DATAERR, "%s: illegal format (line %d)%s",
mapfile, count + 2, not);
}
#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(EX_NOINPUT, "%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(EX_OSERR, "%s%s", gmapfile, not);
if (statbuf.st_mode & S_IWGRP || statbuf.st_mode & S_IWOTH) {
strmode(statbuf.st_mode, buf);
err(EX_NOPERM, "%s: improper write permissions (%s)%s",
gmapfile, buf, not);
}
if (statbuf.st_uid != ROOTUSER)
errx(EX_NOPERM, "%s does not belong to root%s", gmapfile, not);
#endif /* MAPSECURITY */
if ((fscanf(gfp, "%d\n", &gnentries)) != 1)
errx(EX_DATAERR, "%s: nentries not found%s", gmapfile, not);
if (gnentries > MAPFILEENTRIES)
errx(EX_DATAERR,
"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(EX_OSERR, "%s%s", gmapfile, not);
if (feof(gfp))
errx(EX_DATAERR, "%s: unexpected end-of-file%s",
gmapfile, not);
errx(EX_DATAERR, "%s: illegal format (line %d)%s",
gmapfile, count + 2, not);
}
/* Setup mount call args. */
args.target = source;
args.nentries = nentries;
args.mapdata = mapdata;
args.gnentries = gnentries;
args.gmapdata = gmapdata;
if (mount("umapfs", argv[1], mntflags, &args))
err(1, NULL);
exit(0);
}
void
usage()
{
(void)fprintf(stderr,
"usage: mount_umapfs [-o options] -u uid-mapfile -g gid-mapfile target mount-point\n");
exit(EX_USAGE);
}