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freebsd/lib/libufs/inode.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

121 lines
3.4 KiB
C

/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 2002 Juli Mallett. All rights reserved.
*
* This software was written by Juli Mallett <jmallett@FreeBSD.org> for the
* FreeBSD project. Redistribution and use in source and binary forms, with
* or without modification, are permitted provided that the following
* conditions are met:
*
* 1. Redistribution of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* 2. Redistribution 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/mount.h>
#include <sys/disklabel.h>
#include <sys/stat.h>
#include <ufs/ufs/ufsmount.h>
#include <ufs/ufs/dinode.h>
#include <ufs/ffs/fs.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <libufs.h>
int
getinode(struct uufsd *disk, union dinodep *dp, ino_t inum)
{
ino_t min, max;
caddr_t inoblock;
struct fs *fs;
ERROR(disk, NULL);
fs = &disk->d_fs;
if (inum >= (ino_t)fs->fs_ipg * fs->fs_ncg) {
ERROR(disk, "inode number out of range");
return (-1);
}
inoblock = disk->d_inoblock;
min = disk->d_inomin;
max = disk->d_inomax;
if (inoblock == NULL) {
inoblock = malloc(fs->fs_bsize);
if (inoblock == NULL) {
ERROR(disk, "unable to allocate inode block");
return (-1);
}
disk->d_inoblock = inoblock;
}
if (inum >= min && inum < max)
goto gotit;
bread(disk, fsbtodb(fs, ino_to_fsba(fs, inum)), inoblock,
fs->fs_bsize);
disk->d_inomin = min = inum - (inum % INOPB(fs));
disk->d_inomax = max = min + INOPB(fs);
gotit: switch (disk->d_ufs) {
case 1:
disk->d_dp.dp1 = &((struct ufs1_dinode *)inoblock)[inum - min];
if (dp != NULL)
*dp = disk->d_dp;
return (0);
case 2:
disk->d_dp.dp2 = &((struct ufs2_dinode *)inoblock)[inum - min];
if (dp != NULL)
*dp = disk->d_dp;
if (ffs_verify_dinode_ckhash(fs, disk->d_dp.dp2) == 0)
return (0);
ERROR(disk, "check-hash failed for inode read from disk");
return (-1);
default:
break;
}
ERROR(disk, "unknown UFS filesystem type");
return (-1);
}
int
putinode(struct uufsd *disk)
{
struct fs *fs;
fs = &disk->d_fs;
if (disk->d_inoblock == NULL) {
ERROR(disk, "No inode block allocated");
return (-1);
}
if (disk->d_ufs == 2)
ffs_update_dinode_ckhash(fs, disk->d_dp.dp2);
if (bwrite(disk, fsbtodb(fs, ino_to_fsba(&disk->d_fs, disk->d_inomin)),
disk->d_inoblock, disk->d_fs.fs_bsize) <= 0)
return (-1);
return (0);
}