freebsd-skq/sbin/fsirand/fsirand.c
Kirk McKusick 8f829a5cf0 Continuing efforts to provide hardening of FFS. This change adds a
check hash to the filesystem inodes. Access attempts to files
associated with an inode with an invalid check hash will fail with
EINVAL (Invalid argument). Access is reestablished after an fsck
is run to find and validate the inodes with invalid check-hashes.
This check avoids a class of filesystem panics related to corrupted
inodes. The hash is done using crc32c.

Note this check-hash is for the inode itself and not any of its
indirect blocks. Check-hash validation may be extended to also
cover indirect block pointers, but that will be a separate (and
more costly) feature.

Check hashes are added only to UFS2 and not to UFS1 as UFS1 is
primarily used in embedded systems with small memories and low-powered
processors which need as light-weight a filesystem as possible.

Reviewed by:  kib
Tested by:    Peter Holm
Sponsored by: Netflix
2018-12-11 22:14:37 +00:00

237 lines
6.4 KiB
C

/* $OpenBSD: fsirand.c,v 1.9 1997/02/28 00:46:33 millert Exp $ */
/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 1997 Todd C. Miller <Todd.Miller@courtesan.com>
* All rights reserved.
*
* 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. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by Todd C. Miller.
* 4. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED ``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 AUTHOR 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 rcsid[] =
"$FreeBSD$";
#endif /* not lint */
#include <sys/param.h>
#include <sys/resource.h>
#include <ufs/ufs/dinode.h>
#include <ufs/ffs/fs.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <libufs.h>
#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
static void usage(void) __dead2;
int fsirand(char *);
static int printonly = 0, force = 0, ignorelabel = 0;
int
main(int argc, char *argv[])
{
int n, ex = 0;
struct rlimit rl;
while ((n = getopt(argc, argv, "bfp")) != -1) {
switch (n) {
case 'b':
ignorelabel++;
break;
case 'p':
printonly++;
break;
case 'f':
force++;
break;
default:
usage();
}
}
if (argc - optind < 1)
usage();
srandomdev();
/* Increase our data size to the max */
if (getrlimit(RLIMIT_DATA, &rl) == 0) {
rl.rlim_cur = rl.rlim_max;
if (setrlimit(RLIMIT_DATA, &rl) < 0)
warn("can't get resource limit to max data size");
} else
warn("can't get resource limit for data size");
for (n = optind; n < argc; n++) {
if (argc - optind != 1)
(void)puts(argv[n]);
ex += fsirand(argv[n]);
if (n < argc - 1)
putchar('\n');
}
exit(ex);
}
int
fsirand(char *device)
{
struct ufs1_dinode *dp1;
struct ufs2_dinode *dp2;
caddr_t inodebuf;
ssize_t ibufsize;
struct fs *sblock;
ino_t inumber;
ufs2_daddr_t dblk;
int devfd, n, cg, ret;
u_int32_t bsize = DEV_BSIZE;
if ((devfd = open(device, printonly ? O_RDONLY : O_RDWR)) < 0) {
warn("can't open %s", device);
return (1);
}
dp1 = NULL;
dp2 = NULL;
/* Read in master superblock */
if ((ret = sbget(devfd, &sblock, STDSB)) != 0) {
switch (ret) {
case ENOENT:
warn("Cannot find file system superblock");
return (1);
default:
warn("Unable to read file system superblock");
return (1);
}
}
if (sblock->fs_magic == FS_UFS1_MAGIC &&
sblock->fs_old_inodefmt < FS_44INODEFMT) {
warnx("file system format is too old, sorry");
return (1);
}
if (!force && !printonly && sblock->fs_clean != 1) {
warnx("file system is not clean, fsck %s first", device);
return (1);
}
/* XXX - should really cap buffer at 512kb or so */
if (sblock->fs_magic == FS_UFS1_MAGIC)
ibufsize = sizeof(struct ufs1_dinode) * sblock->fs_ipg;
else
ibufsize = sizeof(struct ufs2_dinode) * sblock->fs_ipg;
if ((inodebuf = malloc(ibufsize)) == NULL)
errx(1, "can't allocate memory for inode buffer");
if (printonly && (sblock->fs_id[0] || sblock->fs_id[1])) {
if (sblock->fs_id[0])
(void)printf("%s was randomized on %s", device,
ctime((void *)&(sblock->fs_id[0])));
(void)printf("fsid: %x %x\n", sblock->fs_id[0],
sblock->fs_id[1]);
}
/* Randomize fs_id unless old 4.2BSD file system */
if (!printonly) {
/* Randomize fs_id and write out new sblock and backups */
sblock->fs_id[0] = (u_int32_t)time(NULL);
sblock->fs_id[1] = random();
if (sbput(devfd, sblock, sblock->fs_ncg) != 0) {
warn("could not write updated superblock");
return (1);
}
}
/* For each cylinder group, randomize inodes and update backup sblock */
for (cg = 0, inumber = UFS_ROOTINO; cg < (int)sblock->fs_ncg; cg++) {
/* Read in inodes, then print or randomize generation nums */
dblk = fsbtodb(sblock, ino_to_fsba(sblock, inumber));
if (lseek(devfd, (off_t)dblk * bsize, SEEK_SET) < 0) {
warn("can't seek to %jd", (intmax_t)dblk * bsize);
return (1);
} else if ((n = read(devfd, inodebuf, ibufsize)) != ibufsize) {
warnx("can't read inodes: %s",
(n < ibufsize) ? "short read" : strerror(errno));
return (1);
}
dp1 = (struct ufs1_dinode *)(void *)inodebuf;
dp2 = (struct ufs2_dinode *)(void *)inodebuf;
for (n = cg > 0 ? 0 : UFS_ROOTINO;
n < (int)sblock->fs_ipg;
n++, inumber++) {
if (printonly) {
(void)printf("ino %ju gen %08x\n",
(uintmax_t)inumber,
sblock->fs_magic == FS_UFS1_MAGIC ?
dp1->di_gen : dp2->di_gen);
} else if (sblock->fs_magic == FS_UFS1_MAGIC) {
dp1->di_gen = arc4random();
dp1++;
} else {
dp2->di_gen = arc4random();
ffs_update_dinode_ckhash(sblock, dp2);
dp2++;
}
}
/* Write out modified inodes */
if (!printonly) {
if (lseek(devfd, (off_t)dblk * bsize, SEEK_SET) < 0) {
warn("can't seek to %jd",
(intmax_t)dblk * bsize);
return (1);
} else if ((n = write(devfd, inodebuf, ibufsize)) !=
ibufsize) {
warnx("can't write inodes: %s",
(n != ibufsize) ? "short write" :
strerror(errno));
return (1);
}
}
}
(void)close(devfd);
return(0);
}
static void
usage(void)
{
(void)fprintf(stderr,
"usage: fsirand [-b] [-f] [-p] special [special ...]\n");
exit(1);
}