freebsd-dev/sys/fs/ext2fs/ext2_csum.c
Fedor Uporov 6d4a4ed747 Fix directory blocks checksumming.
Reviewed by:    pfg
MFC after:      3 months

Differential Revision:    https://reviews.freebsd.org/D15396
2018-05-13 19:48:30 +00:00

757 lines
21 KiB
C

/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 2017, Fedor Uporov
* 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.
*
* 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.
*
* $FreeBSD$
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/vnode.h>
#include <sys/bio.h>
#include <sys/buf.h>
#include <sys/endian.h>
#include <sys/conf.h>
#include <sys/mount.h>
#include <fs/ext2fs/fs.h>
#include <fs/ext2fs/ext2fs.h>
#include <fs/ext2fs/ext2_dinode.h>
#include <fs/ext2fs/inode.h>
#include <fs/ext2fs/ext2_dir.h>
#include <fs/ext2fs/htree.h>
#include <fs/ext2fs/ext2_extattr.h>
#include <fs/ext2fs/ext2_extern.h>
#define EXT2_BG_INODE_BITMAP_CSUM_HI_END \
(offsetof(struct ext2_gd, ext4bgd_i_bmap_csum_hi) + \
sizeof(uint16_t))
#define EXT2_INODE_CSUM_HI_EXTRA_END \
(offsetof(struct ext2fs_dinode, e2di_chksum_hi) + sizeof(uint16_t) - \
E2FS_REV0_INODE_SIZE)
#define EXT2_BG_BLOCK_BITMAP_CSUM_HI_LOCATION \
(offsetof(struct ext2_gd, ext4bgd_b_bmap_csum_hi) + \
sizeof(uint16_t))
void
ext2_sb_csum_set_seed(struct m_ext2fs *fs)
{
if (EXT2_HAS_INCOMPAT_FEATURE(fs, EXT2F_INCOMPAT_CSUM_SEED))
fs->e2fs_csum_seed = fs->e2fs->e4fs_chksum_seed;
else if (EXT2_HAS_RO_COMPAT_FEATURE(fs, EXT2F_ROCOMPAT_METADATA_CKSUM)) {
fs->e2fs_csum_seed = calculate_crc32c(~0, fs->e2fs->e2fs_uuid,
sizeof(fs->e2fs->e2fs_uuid));
}
else
fs->e2fs_csum_seed = 0;
}
int
ext2_sb_csum_verify(struct m_ext2fs *fs)
{
if (fs->e2fs->e4fs_chksum_type != EXT4_CRC32C_CHKSUM) {
printf(
"WARNING: mount of %s denied due bad sb csum type\n", fs->e2fs_fsmnt);
return (EINVAL);
}
if (fs->e2fs->e4fs_sbchksum !=
calculate_crc32c(~0, (const char *)fs->e2fs,
offsetof(struct ext2fs, e4fs_sbchksum))) {
printf(
"WARNING: mount of %s denied due bad sb csum=0x%x, expected=0x%x - run fsck\n",
fs->e2fs_fsmnt, fs->e2fs->e4fs_sbchksum, calculate_crc32c(~0,
(const char *)fs->e2fs, offsetof(struct ext2fs, e4fs_sbchksum)));
return (EINVAL);
}
return (0);
}
void
ext2_sb_csum_set(struct m_ext2fs *fs)
{
fs->e2fs->e4fs_sbchksum = calculate_crc32c(~0, (const char *)fs->e2fs,
offsetof(struct ext2fs, e4fs_sbchksum));
}
static uint32_t
ext2_extattr_blk_csum(struct inode *ip, uint64_t facl,
struct ext2fs_extattr_header *header)
{
struct m_ext2fs *fs;
uint32_t crc, old_crc;
fs = ip->i_e2fs;
old_crc = header->h_checksum;
header->h_checksum = 0;
crc = calculate_crc32c(fs->e2fs_csum_seed, (uint8_t *)&facl, sizeof(facl));
crc = calculate_crc32c(crc, (uint8_t *)header, fs->e2fs_bsize);
header->h_checksum = old_crc;
return (crc);
}
int
ext2_extattr_blk_csum_verify(struct inode *ip, struct buf *bp)
{
struct ext2fs_extattr_header *header;
header = (struct ext2fs_extattr_header *)bp->b_data;
if (EXT2_HAS_RO_COMPAT_FEATURE(ip->i_e2fs, EXT2F_ROCOMPAT_METADATA_CKSUM) &&
(header->h_checksum != ext2_extattr_blk_csum(ip, ip->i_facl, header))) {
printf("WARNING: bad extattr csum detected, ip=%lu - run fsck\n",
(unsigned long)ip->i_number);
return (EIO);
}
return (0);
}
void
ext2_extattr_blk_csum_set(struct inode *ip, struct buf *bp)
{
struct ext2fs_extattr_header *header;
if (!EXT2_HAS_RO_COMPAT_FEATURE(ip->i_e2fs, EXT2F_ROCOMPAT_METADATA_CKSUM))
return;
header = (struct ext2fs_extattr_header *)bp->b_data;
header->h_checksum = ext2_extattr_blk_csum(ip, ip->i_facl, header);
}
void
ext2_init_dirent_tail(struct ext2fs_direct_tail *tp)
{
memset(tp, 0, sizeof(struct ext2fs_direct_tail));
tp->e2dt_rec_len = sizeof(struct ext2fs_direct_tail);
tp->e2dt_reserved_ft = EXT2_FT_DIR_CSUM;
}
struct ext2fs_direct_tail *
ext2_dirent_get_tail(struct inode *ip, struct ext2fs_direct_2 *ep)
{
struct ext2fs_direct_2 *dep;
void *top;
struct ext2fs_direct_tail *tp;
unsigned int rec_len;
dep = ep;
top = EXT2_DIRENT_TAIL(ep, ip->i_e2fs->e2fs_bsize);
rec_len = dep->e2d_reclen;
while (rec_len && !(rec_len & 0x3)) {
dep = (struct ext2fs_direct_2 *)(((char *)dep) + rec_len);
if ((void *)dep >= top)
break;
rec_len = dep->e2d_reclen;
}
if (dep != top)
return (NULL);
tp = (struct ext2fs_direct_tail *)dep;
if (tp->e2dt_reserved_zero1 ||
tp->e2dt_rec_len != sizeof(struct ext2fs_direct_tail) ||
tp->e2dt_reserved_zero2 ||
tp->e2dt_reserved_ft != EXT2_FT_DIR_CSUM)
return (NULL);
return (tp);
}
static uint32_t
ext2_dirent_csum(struct inode *ip, struct ext2fs_direct_2 *ep, int size)
{
struct m_ext2fs *fs;
char *buf;
uint32_t inum, gen, crc;
fs = ip->i_e2fs;
buf = (char *)ep;
inum = ip->i_number;
gen = ip->i_gen;
crc = calculate_crc32c(fs->e2fs_csum_seed, (uint8_t *)&inum, sizeof(inum));
crc = calculate_crc32c(crc, (uint8_t *)&gen, sizeof(gen));
crc = calculate_crc32c(crc, (uint8_t *)buf, size);
return (crc);
}
int
ext2_dirent_csum_verify(struct inode *ip, struct ext2fs_direct_2 *ep)
{
uint32_t calculated;
struct ext2fs_direct_tail *tp;
tp = ext2_dirent_get_tail(ip, ep);
if (tp == NULL)
return (0);
calculated = ext2_dirent_csum(ip, ep, (char *)tp - (char *)ep);
if (calculated != tp->e2dt_checksum)
return (EIO);
return (0);
}
static struct ext2fs_htree_count *
ext2_get_dx_count(struct inode *ip, struct ext2fs_direct_2 *ep, int *offset)
{
struct ext2fs_direct_2 *dp;
struct ext2fs_htree_root_info *root;
int count_offset;
if (ep->e2d_reclen == EXT2_BLOCK_SIZE(ip->i_e2fs))
count_offset = 8;
else if (ep->e2d_reclen == 12) {
dp = (struct ext2fs_direct_2 *)(((char *)ep) + 12);
if (dp->e2d_reclen != EXT2_BLOCK_SIZE(ip->i_e2fs) - 12)
return (NULL);
root = (struct ext2fs_htree_root_info *)(((char *)dp + 12));
if (root->h_reserved1 ||
root->h_info_len != sizeof(struct ext2fs_htree_root_info))
return (NULL);
count_offset = 32;
} else
return (NULL);
if (offset)
*offset = count_offset;
return ((struct ext2fs_htree_count *)(((char *)ep) + count_offset));
}
static uint32_t
ext2_dx_csum(struct inode *ip, struct ext2fs_direct_2 *ep, int count_offset,
int count, struct ext2fs_htree_tail *tp)
{
struct m_ext2fs *fs;
char *buf;
int size;
uint32_t inum, old_csum, gen, crc;
fs = ip->i_e2fs;
buf = (char *)ep;
size = count_offset + (count * sizeof(struct ext2fs_htree_entry));
old_csum = tp->ht_checksum;
tp->ht_checksum = 0;
inum = ip->i_number;
gen = ip->i_gen;
crc = calculate_crc32c(fs->e2fs_csum_seed, (uint8_t *)&inum, sizeof(inum));
crc = calculate_crc32c(crc, (uint8_t *)&gen, sizeof(gen));
crc = calculate_crc32c(crc, (uint8_t *)buf, size);
crc = calculate_crc32c(crc, (uint8_t *)tp, sizeof(struct ext2fs_htree_tail));
tp->ht_checksum = old_csum;
return (crc);
}
int
ext2_dx_csum_verify(struct inode *ip, struct ext2fs_direct_2 *ep)
{
uint32_t calculated;
struct ext2fs_htree_count *cp;
struct ext2fs_htree_tail *tp;
int count_offset, limit, count;
cp = ext2_get_dx_count(ip, ep, &count_offset);
if (cp == NULL)
return (0);
limit = cp->h_entries_max;
count = cp->h_entries_num;
if (count_offset + (limit * sizeof(struct ext2fs_htree_entry)) >
ip->i_e2fs->e2fs_bsize - sizeof(struct ext2fs_htree_tail))
return (EIO);
tp = (struct ext2fs_htree_tail *)(((struct ext2fs_htree_entry *)cp) + limit);
calculated = ext2_dx_csum(ip, ep, count_offset, count, tp);
if (tp->ht_checksum != calculated)
return (EIO);
return (0);
}
int
ext2_dir_blk_csum_verify(struct inode *ip, struct buf *bp)
{
struct m_ext2fs *fs;
struct ext2fs_direct_2 *ep;
int error = 0;
fs = ip->i_e2fs;
if (!EXT2_HAS_RO_COMPAT_FEATURE(fs, EXT2F_ROCOMPAT_METADATA_CKSUM))
return (error);
ep = (struct ext2fs_direct_2 *)bp->b_data;
if (ext2_dirent_get_tail(ip, ep) != NULL)
error = ext2_dirent_csum_verify(ip, ep);
else if (ext2_get_dx_count(ip, ep, NULL) != NULL)
error = ext2_dx_csum_verify(ip, ep);
if (error)
printf("WARNING: bad directory csum detected, ip=%lu"
" - run fsck\n", (unsigned long)ip->i_number);
return (error);
}
void
ext2_dirent_csum_set(struct inode *ip, struct ext2fs_direct_2 *ep)
{
struct m_ext2fs *fs;
struct ext2fs_direct_tail *tp;
fs = ip->i_e2fs;
if (!EXT2_HAS_RO_COMPAT_FEATURE(fs, EXT2F_ROCOMPAT_METADATA_CKSUM))
return;
tp = ext2_dirent_get_tail(ip, ep);
if (tp == NULL)
return;
tp->e2dt_checksum =
ext2_dirent_csum(ip, ep, (char *)tp - (char *)ep);
}
void
ext2_dx_csum_set(struct inode *ip, struct ext2fs_direct_2 *ep)
{
struct m_ext2fs *fs;
struct ext2fs_htree_count *cp;
struct ext2fs_htree_tail *tp;
int count_offset, limit, count;
fs = ip->i_e2fs;
if (!EXT2_HAS_RO_COMPAT_FEATURE(fs, EXT2F_ROCOMPAT_METADATA_CKSUM))
return;
cp = ext2_get_dx_count(ip, ep, &count_offset);
if (cp == NULL)
return;
limit = cp->h_entries_max;
count = cp->h_entries_num;
if (count_offset + (limit * sizeof(struct ext2fs_htree_entry)) >
ip->i_e2fs->e2fs_bsize - sizeof(struct ext2fs_htree_tail))
return;
tp = (struct ext2fs_htree_tail *)(((struct ext2fs_htree_entry *)cp) + limit);
tp->ht_checksum = ext2_dx_csum(ip, ep, count_offset, count, tp);
}
static uint32_t
ext2_extent_blk_csum(struct inode *ip, struct ext4_extent_header *ehp)
{
struct m_ext2fs *fs;
size_t size;
uint32_t inum, gen, crc;
fs = ip->i_e2fs;
size = EXT4_EXTENT_TAIL_OFFSET(ehp) +
offsetof(struct ext4_extent_tail, et_checksum);
inum = ip->i_number;
gen = ip->i_gen;
crc = calculate_crc32c(fs->e2fs_csum_seed, (uint8_t *)&inum, sizeof(inum));
crc = calculate_crc32c(crc, (uint8_t *)&gen, sizeof(gen));
crc = calculate_crc32c(crc, (uint8_t *)ehp, size);
return (crc);
}
int
ext2_extent_blk_csum_verify(struct inode *ip, void *data)
{
struct m_ext2fs *fs;
struct ext4_extent_header *ehp;
struct ext4_extent_tail *etp;
uint32_t provided, calculated;
fs = ip->i_e2fs;
if (!EXT2_HAS_RO_COMPAT_FEATURE(fs, EXT2F_ROCOMPAT_METADATA_CKSUM))
return (0);
ehp = (struct ext4_extent_header *)data;
etp = (struct ext4_extent_tail *)(((char *)ehp) +
EXT4_EXTENT_TAIL_OFFSET(ehp));
provided = etp->et_checksum;
calculated = ext2_extent_blk_csum(ip, ehp);
if (provided != calculated) {
printf("WARNING: bad extent csum detected, ip=%lu - run fsck\n",
(unsigned long)ip->i_number);
return (EIO);
}
return (0);
}
void
ext2_extent_blk_csum_set(struct inode *ip, void *data)
{
struct m_ext2fs *fs;
struct ext4_extent_header *ehp;
struct ext4_extent_tail *etp;
fs = ip->i_e2fs;
if (!EXT2_HAS_RO_COMPAT_FEATURE(fs, EXT2F_ROCOMPAT_METADATA_CKSUM))
return;
ehp = (struct ext4_extent_header *)data;
etp = (struct ext4_extent_tail *)(((char *)data) +
EXT4_EXTENT_TAIL_OFFSET(ehp));
etp->et_checksum = ext2_extent_blk_csum(ip,
(struct ext4_extent_header *)data);
}
int
ext2_gd_i_bitmap_csum_verify(struct m_ext2fs *fs, int cg, struct buf *bp)
{
uint32_t hi, provided, calculated;
if (!EXT2_HAS_RO_COMPAT_FEATURE(fs, EXT2F_ROCOMPAT_METADATA_CKSUM))
return (0);
provided = fs->e2fs_gd[cg].ext4bgd_i_bmap_csum;
calculated = calculate_crc32c(fs->e2fs_csum_seed, bp->b_data,
fs->e2fs->e2fs_ipg / 8);
if (fs->e2fs->e3fs_desc_size >= EXT2_BG_INODE_BITMAP_CSUM_HI_END) {
hi = fs->e2fs_gd[cg].ext4bgd_i_bmap_csum_hi;
provided |= (hi << 16);
} else
calculated &= 0xFFFF;
if (provided != calculated) {
printf("WARNING: bad inode bitmap csum detected, "
"cg=%d - run fsck\n", cg);
return (EIO);
}
return (0);
}
void
ext2_gd_i_bitmap_csum_set(struct m_ext2fs *fs, int cg, struct buf *bp)
{
uint32_t csum;
if (!EXT2_HAS_RO_COMPAT_FEATURE(fs, EXT2F_ROCOMPAT_METADATA_CKSUM))
return;
csum = calculate_crc32c(fs->e2fs_csum_seed, bp->b_data,
fs->e2fs->e2fs_ipg / 8);
fs->e2fs_gd[cg].ext4bgd_i_bmap_csum = csum & 0xFFFF;
if (fs->e2fs->e3fs_desc_size >= EXT2_BG_INODE_BITMAP_CSUM_HI_END)
fs->e2fs_gd[cg].ext4bgd_i_bmap_csum_hi = csum >> 16;
}
int
ext2_gd_b_bitmap_csum_verify(struct m_ext2fs *fs, int cg, struct buf *bp)
{
uint32_t hi, provided, calculated, size;
if (!EXT2_HAS_RO_COMPAT_FEATURE(fs, EXT2F_ROCOMPAT_METADATA_CKSUM))
return (0);
size = fs->e2fs_fpg / 8;
provided = fs->e2fs_gd[cg].ext4bgd_b_bmap_csum;
calculated = calculate_crc32c(fs->e2fs_csum_seed, bp->b_data, size);
if (fs->e2fs->e3fs_desc_size >= EXT2_BG_BLOCK_BITMAP_CSUM_HI_LOCATION) {
hi = fs->e2fs_gd[cg].ext4bgd_b_bmap_csum_hi;
provided |= (hi << 16);
} else
calculated &= 0xFFFF;
if (provided != calculated) {
printf("WARNING: bad block bitmap csum detected, "
"cg=%d - run fsck\n", cg);
return (EIO);
}
return (0);
}
void
ext2_gd_b_bitmap_csum_set(struct m_ext2fs *fs, int cg, struct buf *bp)
{
uint32_t csum, size;
if (!EXT2_HAS_RO_COMPAT_FEATURE(fs, EXT2F_ROCOMPAT_METADATA_CKSUM))
return;
size = fs->e2fs_fpg / 8;
csum = calculate_crc32c(fs->e2fs_csum_seed, bp->b_data, size);
fs->e2fs_gd[cg].ext4bgd_b_bmap_csum = csum & 0xFFFF;
if (fs->e2fs->e3fs_desc_size >= EXT2_BG_BLOCK_BITMAP_CSUM_HI_LOCATION)
fs->e2fs_gd[cg].ext4bgd_b_bmap_csum_hi = csum >> 16;
}
static uint32_t
ext2_ei_csum(struct inode *ip, struct ext2fs_dinode *ei)
{
struct m_ext2fs *fs;
uint32_t inode_csum_seed, inum, gen, crc;
uint16_t dummy_csum = 0;
unsigned int offset, csum_size;
fs = ip->i_e2fs;
offset = offsetof(struct ext2fs_dinode, e2di_chksum_lo);
csum_size = sizeof(dummy_csum);
inum = ip->i_number;
crc = calculate_crc32c(fs->e2fs_csum_seed,
(uint8_t *)&inum, sizeof(inum));
gen = ip->i_gen;
inode_csum_seed = calculate_crc32c(crc,
(uint8_t *)&gen, sizeof(gen));
crc = calculate_crc32c(inode_csum_seed, (uint8_t *)ei, offset);
crc = calculate_crc32c(crc, (uint8_t *)&dummy_csum, csum_size);
offset += csum_size;
crc = calculate_crc32c(crc, (uint8_t *)ei + offset,
E2FS_REV0_INODE_SIZE - offset);
if (EXT2_INODE_SIZE(fs) > E2FS_REV0_INODE_SIZE) {
offset = offsetof(struct ext2fs_dinode, e2di_chksum_hi);
crc = calculate_crc32c(crc, (uint8_t *)ei +
E2FS_REV0_INODE_SIZE, offset - E2FS_REV0_INODE_SIZE);
if ((EXT2_INODE_SIZE(ip->i_e2fs) > E2FS_REV0_INODE_SIZE &&
ei->e2di_extra_isize >= EXT2_INODE_CSUM_HI_EXTRA_END)) {
crc = calculate_crc32c(crc, (uint8_t *)&dummy_csum,
csum_size);
offset += csum_size;
}
crc = calculate_crc32c(crc, (uint8_t *)ei + offset,
EXT2_INODE_SIZE(fs) - offset);
}
return (crc);
}
int
ext2_ei_csum_verify(struct inode *ip, struct ext2fs_dinode *ei)
{
struct m_ext2fs *fs;
const static struct ext2fs_dinode ei_zero;
uint32_t hi, provided, calculated;
fs = ip->i_e2fs;
if (!EXT2_HAS_RO_COMPAT_FEATURE(fs, EXT2F_ROCOMPAT_METADATA_CKSUM))
return (0);
provided = ei->e2di_chksum_lo;
calculated = ext2_ei_csum(ip, ei);
if ((EXT2_INODE_SIZE(fs) > E2FS_REV0_INODE_SIZE &&
ei->e2di_extra_isize >= EXT2_INODE_CSUM_HI_EXTRA_END)) {
hi = ei->e2di_chksum_hi;
provided |= hi << 16;
} else
calculated &= 0xFFFF;
if (provided != calculated) {
/*
* If it is first time used dinode,
* it is expected that it will be zeroed
* and we will not return checksum error in this case.
*/
if (!memcmp(ei, &ei_zero, sizeof(struct ext2fs_dinode)))
return (0);
return (EIO);
}
return (0);
}
void
ext2_ei_csum_set(struct inode *ip, struct ext2fs_dinode *ei)
{
struct m_ext2fs *fs;
uint32_t crc;
fs = ip->i_e2fs;
if (!EXT2_HAS_RO_COMPAT_FEATURE(fs, EXT2F_ROCOMPAT_METADATA_CKSUM))
return;
crc = ext2_ei_csum(ip, ei);
ei->e2di_chksum_lo = crc & 0xFFFF;
if ((EXT2_INODE_SIZE(fs) > E2FS_REV0_INODE_SIZE &&
ei->e2di_extra_isize >= EXT2_INODE_CSUM_HI_EXTRA_END))
ei->e2di_chksum_hi = crc >> 16;
}
static uint16_t
ext2_crc16(uint16_t crc, const void *buffer, unsigned int len)
{
const unsigned char *cp = buffer;
/* CRC table for the CRC-16. The poly is 0x8005 (x16 + x15 + x2 + 1). */
static uint16_t const crc16_table[256] = {
0x0000, 0xC0C1, 0xC181, 0x0140, 0xC301, 0x03C0, 0x0280, 0xC241,
0xC601, 0x06C0, 0x0780, 0xC741, 0x0500, 0xC5C1, 0xC481, 0x0440,
0xCC01, 0x0CC0, 0x0D80, 0xCD41, 0x0F00, 0xCFC1, 0xCE81, 0x0E40,
0x0A00, 0xCAC1, 0xCB81, 0x0B40, 0xC901, 0x09C0, 0x0880, 0xC841,
0xD801, 0x18C0, 0x1980, 0xD941, 0x1B00, 0xDBC1, 0xDA81, 0x1A40,
0x1E00, 0xDEC1, 0xDF81, 0x1F40, 0xDD01, 0x1DC0, 0x1C80, 0xDC41,
0x1400, 0xD4C1, 0xD581, 0x1540, 0xD701, 0x17C0, 0x1680, 0xD641,
0xD201, 0x12C0, 0x1380, 0xD341, 0x1100, 0xD1C1, 0xD081, 0x1040,
0xF001, 0x30C0, 0x3180, 0xF141, 0x3300, 0xF3C1, 0xF281, 0x3240,
0x3600, 0xF6C1, 0xF781, 0x3740, 0xF501, 0x35C0, 0x3480, 0xF441,
0x3C00, 0xFCC1, 0xFD81, 0x3D40, 0xFF01, 0x3FC0, 0x3E80, 0xFE41,
0xFA01, 0x3AC0, 0x3B80, 0xFB41, 0x3900, 0xF9C1, 0xF881, 0x3840,
0x2800, 0xE8C1, 0xE981, 0x2940, 0xEB01, 0x2BC0, 0x2A80, 0xEA41,
0xEE01, 0x2EC0, 0x2F80, 0xEF41, 0x2D00, 0xEDC1, 0xEC81, 0x2C40,
0xE401, 0x24C0, 0x2580, 0xE541, 0x2700, 0xE7C1, 0xE681, 0x2640,
0x2200, 0xE2C1, 0xE381, 0x2340, 0xE101, 0x21C0, 0x2080, 0xE041,
0xA001, 0x60C0, 0x6180, 0xA141, 0x6300, 0xA3C1, 0xA281, 0x6240,
0x6600, 0xA6C1, 0xA781, 0x6740, 0xA501, 0x65C0, 0x6480, 0xA441,
0x6C00, 0xACC1, 0xAD81, 0x6D40, 0xAF01, 0x6FC0, 0x6E80, 0xAE41,
0xAA01, 0x6AC0, 0x6B80, 0xAB41, 0x6900, 0xA9C1, 0xA881, 0x6840,
0x7800, 0xB8C1, 0xB981, 0x7940, 0xBB01, 0x7BC0, 0x7A80, 0xBA41,
0xBE01, 0x7EC0, 0x7F80, 0xBF41, 0x7D00, 0xBDC1, 0xBC81, 0x7C40,
0xB401, 0x74C0, 0x7580, 0xB541, 0x7700, 0xB7C1, 0xB681, 0x7640,
0x7200, 0xB2C1, 0xB381, 0x7340, 0xB101, 0x71C0, 0x7080, 0xB041,
0x5000, 0x90C1, 0x9181, 0x5140, 0x9301, 0x53C0, 0x5280, 0x9241,
0x9601, 0x56C0, 0x5780, 0x9741, 0x5500, 0x95C1, 0x9481, 0x5440,
0x9C01, 0x5CC0, 0x5D80, 0x9D41, 0x5F00, 0x9FC1, 0x9E81, 0x5E40,
0x5A00, 0x9AC1, 0x9B81, 0x5B40, 0x9901, 0x59C0, 0x5880, 0x9841,
0x8801, 0x48C0, 0x4980, 0x8941, 0x4B00, 0x8BC1, 0x8A81, 0x4A40,
0x4E00, 0x8EC1, 0x8F81, 0x4F40, 0x8D01, 0x4DC0, 0x4C80, 0x8C41,
0x4400, 0x84C1, 0x8581, 0x4540, 0x8701, 0x47C0, 0x4680, 0x8641,
0x8201, 0x42C0, 0x4380, 0x8341, 0x4100, 0x81C1, 0x8081, 0x4040
};
while (len--)
crc = (((crc >> 8) & 0xffU) ^
crc16_table[(crc ^ *cp++) & 0xffU]) & 0x0000ffffU;
return crc;
}
static uint16_t
ext2_gd_csum(struct m_ext2fs *fs, uint32_t block_group, struct ext2_gd *gd)
{
size_t offset;
uint32_t csum32;
uint16_t crc, dummy_csum;
offset = offsetof(struct ext2_gd, ext4bgd_csum);
if (EXT2_HAS_RO_COMPAT_FEATURE(fs, EXT2F_ROCOMPAT_METADATA_CKSUM)) {
csum32 = calculate_crc32c(fs->e2fs_csum_seed,
(uint8_t *)&block_group, sizeof(block_group));
csum32 = calculate_crc32c(csum32, (uint8_t *)gd, offset);
dummy_csum = 0;
csum32 = calculate_crc32c(csum32, (uint8_t *)&dummy_csum,
sizeof(dummy_csum));
offset += sizeof(dummy_csum);
if (offset < fs->e2fs->e3fs_desc_size)
csum32 = calculate_crc32c(csum32, (uint8_t *)gd + offset,
fs->e2fs->e3fs_desc_size - offset);
crc = csum32 & 0xFFFF;
return (crc);
} else if (EXT2_HAS_RO_COMPAT_FEATURE(fs, EXT2F_ROCOMPAT_GDT_CSUM)) {
crc = ext2_crc16(~0, fs->e2fs->e2fs_uuid,
sizeof(fs->e2fs->e2fs_uuid));
crc = ext2_crc16(crc, (uint8_t *)&block_group,
sizeof(block_group));
crc = ext2_crc16(crc, (uint8_t *)gd, offset);
offset += sizeof(gd->ext4bgd_csum); /* skip checksum */
if (EXT2_HAS_INCOMPAT_FEATURE(fs, EXT2F_INCOMPAT_64BIT) &&
offset < fs->e2fs->e3fs_desc_size)
crc = ext2_crc16(crc, (uint8_t *)gd + offset,
fs->e2fs->e3fs_desc_size - offset);
return (crc);
}
return (0);
}
int
ext2_gd_csum_verify(struct m_ext2fs *fs, struct cdev *dev)
{
unsigned int i;
int error = 0;
for (i = 0; i < fs->e2fs_gcount; i++) {
if (fs->e2fs_gd[i].ext4bgd_csum !=
ext2_gd_csum(fs, i, &fs->e2fs_gd[i])) {
printf(
"WARNING: mount of %s denied due bad gd=%d csum=0x%x, expected=0x%x - run fsck\n",
devtoname(dev), i, fs->e2fs_gd[i].ext4bgd_csum,
ext2_gd_csum(fs, i, &fs->e2fs_gd[i]));
error = EIO;
break;
}
}
return (error);
}
void
ext2_gd_csum_set(struct m_ext2fs *fs)
{
unsigned int i;
for (i = 0; i < fs->e2fs_gcount; i++)
fs->e2fs_gd[i].ext4bgd_csum =
ext2_gd_csum(fs, i, &fs->e2fs_gd[i]);
}