/*
* csum.c --- checksumming of ext3 structures
*
* Copyright (C) 2006 Cluster File Systems, Inc.
* Copyright (C) 2006, 2007 by Andreas Dilger <adilger@clusterfs.com>
*
* %Begin-Header%
* This file may be redistributed under the terms of the GNU Library
* General Public License, version 2.
* %End-Header%
*/
#include "config.h"
#if HAVE_SYS_TYPES_H
#include <sys/types.h>
#endif
#include "ext2_fs.h"
#include "ext2fs.h"
#include "crc16.h"
#include <assert.h>
#ifndef offsetof
#define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)
#endif
#ifdef DEBUG
#define STATIC
#else
#define STATIC static
#endif
void ext2fs_init_csum_seed(ext2_filsys fs)
{
if (ext2fs_has_feature_csum_seed(fs->super))
fs->csum_seed = fs->super->s_checksum_seed;
else if (ext2fs_has_feature_metadata_csum(fs->super))
fs->csum_seed = ext2fs_crc32c_le(~0, fs->super->s_uuid,
sizeof(fs->super->s_uuid));
}
static __u32 ext2fs_mmp_csum(ext2_filsys fs, struct mmp_struct *mmp)
{
int offset = offsetof(struct mmp_struct, mmp_checksum);
return ext2fs_crc32c_le(fs->csum_seed, (unsigned char *)mmp, offset);
}
int ext2fs_mmp_csum_verify(ext2_filsys fs, struct mmp_struct *mmp)
{
__u32 calculated;
if (!ext2fs_has_feature_metadata_csum(fs->super))
return 1;
calculated = ext2fs_mmp_csum(fs, mmp);
return ext2fs_le32_to_cpu(mmp->mmp_checksum) == calculated;
}
errcode_t ext2fs_mmp_csum_set(ext2_filsys fs, struct mmp_struct *mmp)
{
__u32 crc;
if (!ext2fs_has_feature_metadata_csum(fs->super))
return 0;
crc = ext2fs_mmp_csum(fs, mmp);
mmp->mmp_checksum = ext2fs_cpu_to_le32(crc);
return 0;
}
int ext2fs_verify_csum_type(ext2_filsys fs, struct ext2_super_block *sb)
{
if (!ext2fs_has_feature_metadata_csum(fs->super))
return 1;
return sb->s_checksum_type == EXT2_CRC32C_CHKSUM;
}
static __u32 ext2fs_superblock_csum(ext2_filsys fs EXT2FS_ATTR((unused)),
struct ext2_super_block *sb)
{
int offset = offsetof(struct ext2_super_block, s_checksum);
return ext2fs_crc32c_le(~0, (unsigned char *)sb, offset);
}
/* NOTE: The input to this function MUST be in LE order */
int ext2fs_superblock_csum_verify(ext2_filsys fs, struct ext2_super_block *sb)
{
__u32 flag, calculated;
if (fs->flags & EXT2_FLAG_SWAP_BYTES)
flag = EXT4_FEATURE_RO_COMPAT_METADATA_CSUM;
else
flag = ext2fs_cpu_to_le32(EXT4_FEATURE_RO_COMPAT_METADATA_CSUM);
if (!EXT2_HAS_RO_COMPAT_FEATURE(fs->super, flag))
return 1;
calculated = ext2fs_superblock_csum(fs, sb);
return ext2fs_le32_to_cpu(sb->s_checksum) == calculated;
}
/* NOTE: The input to this function MUST be in LE order */
errcode_t ext2fs_superblock_csum_set(ext2_filsys fs,
struct ext2_super_block *sb)
{
__u32 flag, crc;
if (fs->flags & EXT2_FLAG_SWAP_BYTES)
flag = EXT4_FEATURE_RO_COMPAT_METADATA_CSUM;
else
flag = ext2fs_cpu_to_le32(EXT4_FEATURE_RO_COMPAT_METADATA_CSUM);
if (!EXT2_HAS_RO_COMPAT_FEATURE(fs->super, flag))
return 0;
crc = ext2fs_superblock_csum(fs, sb);
sb->s_checksum = ext2fs_cpu_to_le32(crc);
return 0;
}
static errcode_t ext2fs_ext_attr_block_csum(ext2_filsys fs,
ext2_ino_t inum EXT2FS_ATTR((unused)),
blk64_t block,
struct ext2_ext_attr_header *hdr,
__u32 *crc)
{
char *buf = (char *)hdr;
__u32 old_crc = hdr->h_checksum;
hdr->h_checksum = 0;
block = ext2fs_cpu_to_le64(block);
*crc = ext2fs_crc32c_le(fs->csum_seed, (unsigned char *)&block,
sizeof(block));
*crc = ext2fs_crc32c_le(*crc, (unsigned char *)buf, fs->blocksize);
hdr->h_checksum = old_crc;
return 0;
}
int ext2fs_ext_attr_block_csum_verify(ext2_filsys fs, ext2_ino_t inum,
blk64_t block,
struct ext2_ext_attr_header *hdr)
{
__u32 calculated;
errcode_t retval;
if (!ext2fs_has_feature_metadata_csum(fs->super))
return 1;
retval = ext2fs_ext_attr_block_csum(fs, inum, block, hdr, &calculated);
if (retval)
return 0;
return ext2fs_le32_to_cpu(hdr->h_checksum) == calculated;
}
errcode_t ext2fs_ext_attr_block_csum_set(ext2_filsys fs, ext2_ino_t inum,
blk64_t block,
struct ext2_ext_attr_header *hdr)
{
errcode_t retval;
__u32 crc;
if (!ext2fs_has_feature_metadata_csum(fs->super))
return 0;
retval = ext2fs_ext_attr_block_csum(fs, inum, block, hdr, &crc);
if (retval)
return retval;
hdr->h_checksum = ext2fs_cpu_to_le32(crc);
return 0;
}
static __u16 do_nothing16(__u16 x)
{
return x;
}
static __u16 disk_to_host16(__u16 x)
{
return ext2fs_le16_to_cpu(x);
}
static errcode_t __get_dx_countlimit(ext2_filsys fs,
struct ext2_dir_entry *dirent,
struct ext2_dx_countlimit **cc,
int *offset,
int need_swab)
{
struct ext2_dir_entry *dp;
struct ext2_dx_root_info *root;
struct ext2_dx_countlimit *c;
int count_offset, max_sane_entries;
unsigned int rec_len;
__u16 (*translate)(__u16) = (need_swab ? disk_to_host16 : do_nothing16);
rec_len = translate(dirent->rec_len);
if (rec_len == fs->blocksize && translate(dirent->name_len) == 0)
count_offset = 8;
else if (rec_len == 12) {
dp = (struct ext2_dir_entry *)(((char *)dirent) + rec_len);
rec_len = translate(dp->rec_len);
if (rec_len != fs->blocksize - 12)
return EXT2_ET_DB_NOT_FOUND;
root = (struct ext2_dx_root_info *)(((char *)dp + 12));
if (root->reserved_zero ||
root->info_length != sizeof(struct ext2_dx_root_info))
return EXT2_ET_DB_NOT_FOUND;
count_offset = 32;
} else
return EXT2_ET_DB_NOT_FOUND;
c = (struct ext2_dx_countlimit *)(((char *)dirent) + count_offset);
max_sane_entries = (fs->blocksize - count_offset) /
sizeof(struct ext2_dx_entry);
if (ext2fs_le16_to_cpu(c->limit) > max_sane_entries ||
ext2fs_le16_to_cpu(c->count) > max_sane_entries)
return EXT2_ET_DIR_NO_SPACE_FOR_CSUM;
if (offset)
*offset = count_offset;
if (cc)
*cc = c;
return 0;
}
errcode_t ext2fs_get_dx_countlimit(ext2_filsys fs,
struct ext2_dir_entry *dirent,
struct ext2_dx_countlimit **cc,
int *offset)
{
return __get_dx_countlimit(fs, dirent, cc, offset, 0);
}
void ext2fs_initialize_dirent_tail(ext2_filsys fs,
struct ext2_dir_entry_tail *t)
{
memset(t, 0, sizeof(struct ext2_dir_entry_tail));
ext2fs_set_rec_len(fs, sizeof(struct ext2_dir_entry_tail),
(struct ext2_dir_entry *)t);
t->det_reserved_name_len = EXT2_DIR_NAME_LEN_CSUM;
}
static errcode_t __get_dirent_tail(ext2_filsys fs,
struct ext2_dir_entry *dirent,
struct ext2_dir_entry_tail **tt,
int need_swab)
{
struct ext2_dir_entry *d;
void *top;
struct ext2_dir_entry_tail *t;
unsigned int rec_len;
errcode_t retval = 0;
__u16 (*translate)(__u16) = (need_swab ? disk_to_host16 : do_nothing16);
d = dirent;
top = EXT2_DIRENT_TAIL(dirent, fs->blocksize);
rec_len = translate(d->rec_len);
while (rec_len && !(rec_len & 0x3)) {
d = (struct ext2_dir_entry *)(((char *)d) + rec_len);
if ((void *)d >= top)
break;
rec_len = translate(d->rec_len);
}
if (d != top)
return EXT2_ET_DIR_NO_SPACE_FOR_CSUM;
t = (struct ext2_dir_entry_tail *)d;
if (t->det_reserved_zero1 ||
translate(t->det_rec_len) != sizeof(struct ext2_dir_entry_tail) ||
translate(t->det_reserved_name_len) != EXT2_DIR_NAME_LEN_CSUM)
return EXT2_ET_DIR_NO_SPACE_FOR_CSUM;
if (tt)
*tt = t;
return retval;
}
int ext2fs_dirent_has_tail(ext2_filsys fs, struct ext2_dir_entry *dirent)
{
return __get_dirent_tail(fs, dirent, NULL, 0) == 0;
}
static errcode_t ext2fs_dirent_csum(ext2_filsys fs, ext2_ino_t inum,
struct ext2_dir_entry *dirent, __u32 *crc,
int size)
{
errcode_t retval;
char *buf = (char *)dirent;
__u32 gen;
struct ext2_inode inode;
retval = ext2fs_read_inode(fs, inum, &inode);
if (retval)
return retval;
inum = ext2fs_cpu_to_le32(inum);
gen = ext2fs_cpu_to_le32(inode.i_generation);
*crc = ext2fs_crc32c_le(fs->csum_seed, (unsigned char *)&inum,
sizeof(inum));
*crc = ext2fs_crc32c_le(*crc, (unsigned char *)&gen, sizeof(gen));
*crc = ext2fs_crc32c_le(*crc, (unsigned char *)buf, size);
return 0;
}
int ext2fs_dirent_csum_verify(ext2_filsys fs, ext2_ino_t inum,
struct ext2_dir_entry *dirent)
{
errcode_t retval;
__u32 calculated;
struct ext2_dir_entry_tail *t;
retval = __get_dirent_tail(fs, dirent, &t, 1);
if (retval)
return 1;
/*
* The checksum field is overlaid with the dirent->name field
* so the swapfs.c functions won't change the endianness.
*/
retval = ext2fs_dirent_csum(fs, inum, dirent, &calculated,
(char *)t - (char *)dirent);
if (retval)
return 0;
return ext2fs_le32_to_cpu(t->det_checksum) == calculated;
}
static errcode_t ext2fs_dirent_csum_set(ext2_filsys fs, ext2_ino_t inum,
struct ext2_dir_entry *dirent)
{
errcode_t retval;
__u32 crc;
struct ext2_dir_entry_tail *t;
retval = __get_dirent_tail(fs, dirent, &t, 1);
if (retval)
return retval;
/* swapfs.c functions don't change the checksum endianness */
retval = ext2fs_dirent_csum(fs, inum, dirent, &crc,
(char *)t - (char *)dirent);
if (retval)
return retval;
t->det_checksum = ext2fs_cpu_to_le32(crc);
return 0;
}
static errcode_t ext2fs_dx_csum(ext2_filsys fs, ext2_ino_t inum,
struct ext2_dir_entry *dirent,
__u32 *crc, int count_offset, int count,
struct ext2_dx_tail *t)
{
errcode_t retval;
char *buf = (char *)dirent;
int size;
__u32 old_csum, gen;
struct ext2_inode inode;
size = count_offset + (count * sizeof(struct ext2_dx_entry));
old_csum = t->dt_checksum;
t->dt_checksum = 0;
retval = ext2fs_read_inode(fs, inum, &inode);
if (retval)
return retval;
inum = ext2fs_cpu_to_le32(inum);
gen = ext2fs_cpu_to_le32(inode.i_generation);
*crc = ext2fs_crc32c_le(fs->csum_seed, (unsigned char *)&inum,
sizeof(inum));
*crc = ext2fs_crc32c_le(*crc, (unsigned char *)&gen, sizeof(gen));
*crc = ext2fs_crc32c_le(*crc, (unsigned char *)buf, size);
*crc = ext2fs_crc32c_le(*crc, (unsigned char *)t,
sizeof(struct ext2_dx_tail));
t->dt_checksum = old_csum;
return 0;
}
static int ext2fs_dx_csum_verify(ext2_filsys fs, ext2_ino_t inum,
struct ext2_dir_entry *dirent)
{
__u32 calculated;
errcode_t retval;
struct ext2_dx_countlimit *c;
struct ext2_dx_tail *t;
int count_offset, limit, count;
retval = __get_dx_countlimit(fs, dirent, &c, &count_offset, 1);
if (retval)
return 1;
limit = ext2fs_le16_to_cpu(c->limit);
count = ext2fs_le16_to_cpu(c->count);
if (count_offset + (limit * sizeof(struct ext2_dx_entry)) >
fs->blocksize - sizeof(struct ext2_dx_tail))
return 0;
/* htree structs are accessed in LE order */
t = (struct ext2_dx_tail *)(((struct ext2_dx_entry *)c) + limit);
retval = ext2fs_dx_csum(fs, inum, dirent, &calculated, count_offset,
count, t);
if (retval)
return 0;
return ext2fs_le32_to_cpu(t->dt_checksum) == calculated;
}
static errcode_t ext2fs_dx_csum_set(ext2_filsys fs, ext2_ino_t inum,
struct ext2_dir_entry *dirent)
{
__u32 crc;
errcode_t retval = 0;
struct ext2_dx_countlimit *c;
struct ext2_dx_tail *t;
int count_offset, limit, count;
retval = __get_dx_countlimit(fs, dirent, &c, &count_offset, 1);
if (retval)
return retval;
limit = ext2fs_le16_to_cpu(c->limit);
count = ext2fs_le16_to_cpu(c->count);
if (count_offset + (limit * sizeof(struct ext2_dx_entry)) >
fs->blocksize - sizeof(struct ext2_dx_tail))
return EXT2_ET_DIR_NO_SPACE_FOR_CSUM;
t = (struct ext2_dx_tail *)(((struct ext2_dx_entry *)c) + limit);
/* htree structs are accessed in LE order */
retval = ext2fs_dx_csum(fs, inum, dirent, &crc, count_offset, count, t);
if (retval)
return retval;
t->dt_checksum = ext2fs_cpu_to_le32(crc);
return retval;
}
int ext2fs_dir_block_csum_verify(ext2_filsys fs, ext2_ino_t inum,
struct ext2_dir_entry *dirent)
{
if (!ext2fs_has_feature_metadata_csum(fs->super))
return 1;
if (__get_dirent_tail(fs, dirent, NULL, 1) == 0)
return ext2fs_dirent_csum_verify(fs, inum, dirent);
if (__get_dx_countlimit(fs, dirent, NULL, NULL, 1) == 0)
return ext2fs_dx_csum_verify(fs, inum, dirent);
return 0;
}
errcode_t ext2fs_dir_block_csum_set(ext2_filsys fs, ext2_ino_t inum,
struct ext2_dir_entry *dirent)
{
if (!ext2fs_has_feature_metadata_csum(fs->super))
return 0;
if (__get_dirent_tail(fs, dirent, NULL, 1) == 0)
return ext2fs_dirent_csum_set(fs, inum, dirent);
if (__get_dx_countlimit(fs, dirent, NULL, NULL, 1) == 0)
return ext2fs_dx_csum_set(fs, inum, dirent);
if (fs->flags & EXT2_FLAG_IGNORE_CSUM_ERRORS)
return 0;
return EXT2_ET_DIR_NO_SPACE_FOR_CSUM;
}
#define EXT3_EXTENT_TAIL_OFFSET(hdr) (sizeof(struct ext3_extent_header) + \
(sizeof(struct ext3_extent) * ext2fs_le16_to_cpu((hdr)->eh_max)))
static struct ext3_extent_tail *get_extent_tail(struct ext3_extent_header *h)
{
return (struct ext3_extent_tail *)(((char *)h) +
EXT3_EXTENT_TAIL_OFFSET(h));
}
static errcode_t ext2fs_extent_block_csum(ext2_filsys fs, ext2_ino_t inum,
struct ext3_extent_header *eh,
__u32 *crc)
{
int size;
__u32 gen;
errcode_t retval;
struct ext2_inode inode;
size = EXT3_EXTENT_TAIL_OFFSET(eh) + offsetof(struct ext3_extent_tail,
et_checksum);
retval = ext2fs_read_inode(fs, inum, &inode);
if (retval)
return retval;
inum = ext2fs_cpu_to_le32(inum);
gen = ext2fs_cpu_to_le32(inode.i_generation);
*crc = ext2fs_crc32c_le(fs->csum_seed, (unsigned char *)&inum,
sizeof(inum));
*crc = ext2fs_crc32c_le(*crc, (unsigned char *)&gen, sizeof(gen));
*crc = ext2fs_crc32c_le(*crc, (unsigned char *)eh, size);
return 0;
}
int ext2fs_extent_block_csum_verify(ext2_filsys fs, ext2_ino_t inum,
struct ext3_extent_header *eh)
{
errcode_t retval;
__u32 provided, calculated;
struct ext3_extent_tail *t = get_extent_tail(eh);
/*
* The extent tree structures are accessed in LE order, so we must
* swap the checksum bytes here.
*/
if (!ext2fs_has_feature_metadata_csum(fs->super))
return 1;
provided = ext2fs_le32_to_cpu(t->et_checksum);
retval = ext2fs_extent_block_csum(fs, inum, eh, &calculated);
if (retval)
return 0;
return provided == calculated;
}
errcode_t ext2fs_extent_block_csum_set(ext2_filsys fs, ext2_ino_t inum,
struct ext3_extent_header *eh)
{
errcode_t retval;
__u32 crc;
struct ext3_extent_tail *t = get_extent_tail(eh);
if (!ext2fs_has_feature_metadata_csum(fs->super))
return 0;
/*
* The extent tree structures are accessed in LE order, so we must
* swap the checksum bytes here.
*/
retval = ext2fs_extent_block_csum(fs, inum, eh, &crc);
if (retval)
return retval;
t->et_checksum = ext2fs_cpu_to_le32(crc);
return retval;
}
int ext2fs_inode_bitmap_csum_verify(ext2_filsys fs, dgrp_t group,
char *bitmap, int size)
{
struct ext4_group_desc *gdp = (struct ext4_group_desc *)
ext2fs_group_desc(fs, fs->group_desc, group);
__u32 provided, calculated;
if (!ext2fs_has_feature_metadata_csum(fs->super))
return 1;
provided = gdp->bg_inode_bitmap_csum_lo;
calculated = ext2fs_crc32c_le(fs->csum_seed, (unsigned char *)bitmap,
size);
if (fs->super->s_desc_size >= EXT4_BG_INODE_BITMAP_CSUM_HI_END)
provided |= (__u32)gdp->bg_inode_bitmap_csum_hi << 16;
else
calculated &= 0xFFFF;
return provided == calculated;
}
errcode_t ext2fs_inode_bitmap_csum_set(ext2_filsys fs, dgrp_t group,
char *bitmap, int size)
{
__u32 crc;
struct ext4_group_desc *gdp = (struct ext4_group_desc *)
ext2fs_group_desc(fs, fs->group_desc, group);
if (!ext2fs_has_feature_metadata_csum(fs->super))
return 0;
crc = ext2fs_crc32c_le(fs->csum_seed, (unsigned char *)bitmap, size);
gdp->bg_inode_bitmap_csum_lo = crc & 0xFFFF;
if (fs->super->s_desc_size >= EXT4_BG_INODE_BITMAP_CSUM_HI_END)
gdp->bg_inode_bitmap_csum_hi = crc >> 16;
return 0;
}
int ext2fs_block_bitmap_csum_verify(ext2_filsys fs, dgrp_t group,
char *bitmap, int size)
{
struct ext4_group_desc *gdp = (struct ext4_group_desc *)
ext2fs_group_desc(fs, fs->group_desc, group);
__u32 provided, calculated;
if (!ext2fs_has_feature_metadata_csum(fs->super))
return 1;
provided = gdp->bg_block_bitmap_csum_lo;
calculated = ext2fs_crc32c_le(fs->csum_seed, (unsigned char *)bitmap,
size);
if (fs->super->s_desc_size >= EXT4_BG_BLOCK_BITMAP_CSUM_HI_LOCATION)
provided |= (__u32)gdp->bg_block_bitmap_csum_hi << 16;
else
calculated &= 0xFFFF;
return provided == calculated;
}
errcode_t ext2fs_block_bitmap_csum_set(ext2_filsys fs, dgrp_t group,
char *bitmap, int size)
{
__u32 crc;
struct ext4_group_desc *gdp = (struct ext4_group_desc *)
ext2fs_group_desc(fs, fs->group_desc, group);
if (!ext2fs_has_feature_metadata_csum(fs->super))
return 0;
crc = ext2fs_crc32c_le(fs->csum_seed, (unsigned char *)bitmap, size);
gdp->bg_block_bitmap_csum_lo = crc & 0xFFFF;
if (fs->super->s_desc_size >= EXT4_BG_BLOCK_BITMAP_CSUM_HI_LOCATION)
gdp->bg_block_bitmap_csum_hi = crc >> 16;
return 0;
}
static errcode_t ext2fs_inode_csum(ext2_filsys fs, ext2_ino_t inum,
struct ext2_inode_large *inode,
__u32 *crc, int has_hi)
{
__u32 gen;
struct ext2_inode_large *desc = inode;
size_t size = fs->super->s_inode_size;
__u16 old_lo;
__u16 old_hi = 0;
old_lo = inode->i_checksum_lo;
inode->i_checksum_lo = 0;
if (has_hi) {
old_hi = inode->i_checksum_hi;
inode->i_checksum_hi = 0;
}
inum = ext2fs_cpu_to_le32(inum);
gen = inode->i_generation;
*crc = ext2fs_crc32c_le(fs->csum_seed, (unsigned char *)&inum,
sizeof(inum));
*crc = ext2fs_crc32c_le(*crc, (unsigned char *)&gen, sizeof(gen));
*crc = ext2fs_crc32c_le(*crc, (unsigned char *)desc, size);
inode->i_checksum_lo = old_lo;
if (has_hi)
inode->i_checksum_hi = old_hi;
return 0;
}
int ext2fs_inode_csum_verify(ext2_filsys fs, ext2_ino_t inum,
struct ext2_inode_large *inode)
{
errcode_t retval;
__u32 provided, calculated;
unsigned int i, has_hi;
char *cp;
if (!ext2fs_has_feature_metadata_csum(fs->super))
return 1;
has_hi = (EXT2_INODE_SIZE(fs->super) > EXT2_GOOD_OLD_INODE_SIZE &&
inode->i_extra_isize >= EXT4_INODE_CSUM_HI_EXTRA_END);
provided = ext2fs_le16_to_cpu(inode->i_checksum_lo);
retval = ext2fs_inode_csum(fs, inum, inode, &calculated, has_hi);
if (retval)
return 0;
if (has_hi) {
__u32 hi = ext2fs_le16_to_cpu(inode->i_checksum_hi);
provided |= hi << 16;
} else
calculated &= 0xFFFF;
if (provided == calculated)
return 1;
/*
* If the checksum didn't match, it's possible it was due to
* the inode being all zero's. It's unlikely this is the
* case, but it can happen. So check for it here. (We only
* check the base inode since that's good enough, and it's not
* worth the bother to figure out how much of the extended
* inode, if any, is present.)
*/
for (cp = (char *) inode, i = 0;
i < sizeof(struct ext2_inode);
cp++, i++)
if (*cp)
return 0;
return 1; /* Inode must have been all zero's */
}
errcode_t ext2fs_inode_csum_set(ext2_filsys fs, ext2_ino_t inum,
struct ext2_inode_large *inode)
{
errcode_t retval;
__u32 crc;
int has_hi;
if (!ext2fs_has_feature_metadata_csum(fs->super))
return 0;
has_hi = (EXT2_INODE_SIZE(fs->super) > EXT2_GOOD_OLD_INODE_SIZE &&
inode->i_extra_isize >= EXT4_INODE_CSUM_HI_EXTRA_END);
retval = ext2fs_inode_csum(fs, inum, inode, &crc, has_hi);
if (retval)
return retval;
inode->i_checksum_lo = ext2fs_cpu_to_le16(crc & 0xFFFF);
if (has_hi)
inode->i_checksum_hi = ext2fs_cpu_to_le16(crc >> 16);
return 0;
}
__u16 ext2fs_group_desc_csum(ext2_filsys fs, dgrp_t group)
{
struct ext2_group_desc *desc = ext2fs_group_desc(fs, fs->group_desc,
group);
size_t offset, size = EXT2_DESC_SIZE(fs->super);
__u16 crc = 0;
#ifdef WORDS_BIGENDIAN
struct ext4_group_desc swabdesc;
size_t save_size = size;
const size_t ext4_bg_size = sizeof(struct ext4_group_desc);
struct ext2_group_desc *save_desc = desc;
/* Have to swab back to little-endian to do the checksum */
if (size > ext4_bg_size)
size = ext4_bg_size;
memcpy(&swabdesc, desc, size);
ext2fs_swap_group_desc2(fs, (struct ext2_group_desc *) &swabdesc);
desc = (struct ext2_group_desc *) &swabdesc;
group = ext2fs_swab32(group);
#endif
if (ext2fs_has_feature_metadata_csum(fs->super)) {
/* new metadata csum code */
__u16 old_crc;
__u32 crc32;
old_crc = desc->bg_checksum;
desc->bg_checksum = 0;
crc32 = ext2fs_crc32c_le(fs->csum_seed, (unsigned char *)&group,
sizeof(group));
crc32 = ext2fs_crc32c_le(crc32, (unsigned char *)desc,
size);
desc->bg_checksum = old_crc;
#ifdef WORDS_BIGENDIAN
if (save_size > ext4_bg_size)
crc32 = ext2fs_crc32c_le(crc32,
(unsigned char *)save_desc + ext4_bg_size,
save_size - ext4_bg_size);
#endif
crc = crc32 & 0xFFFF;
goto out;
}
/* old crc16 code */
offset = offsetof(struct ext2_group_desc, bg_checksum);
crc = ext2fs_crc16(~0, fs->super->s_uuid,
sizeof(fs->super->s_uuid));
crc = ext2fs_crc16(crc, &group, sizeof(group));
crc = ext2fs_crc16(crc, desc, offset);
offset += sizeof(desc->bg_checksum); /* skip checksum */
/* for checksum of struct ext4_group_desc do the rest...*/
if (offset < size) {
crc = ext2fs_crc16(crc, (char *)desc + offset,
size - offset);
}
#ifdef WORDS_BIGENDIAN
/*
* If the size of the bg descriptor is greater than 64
* bytes, which is the size of the traditional ext4 bg
* descriptor, checksum the rest of the descriptor here
*/
if (save_size > ext4_bg_size)
crc = ext2fs_crc16(crc, (char *)save_desc + ext4_bg_size,
save_size - ext4_bg_size);
#endif
out:
return crc;
}
int ext2fs_group_desc_csum_verify(ext2_filsys fs, dgrp_t group)
{
if (ext2fs_has_group_desc_csum(fs) &&
(ext2fs_bg_checksum(fs, group) !=
ext2fs_group_desc_csum(fs, group)))
return 0;
return 1;
}
void ext2fs_group_desc_csum_set(ext2_filsys fs, dgrp_t group)
{
if (!ext2fs_has_group_desc_csum(fs))
return;
/* ext2fs_bg_checksum_set() sets the actual checksum field but
* does not calculate the checksum itself. */
ext2fs_bg_checksum_set(fs, group, ext2fs_group_desc_csum(fs, group));
}
static __u32 find_last_inode_ingrp(ext2fs_inode_bitmap bitmap,
__u32 inodes_per_grp, dgrp_t grp_no)
{
ext2_ino_t i, start_ino, end_ino;
start_ino = grp_no * inodes_per_grp + 1;
end_ino = start_ino + inodes_per_grp - 1;
for (i = end_ino; i >= start_ino; i--) {
if (ext2fs_fast_test_inode_bitmap2(bitmap, i))
return i - start_ino + 1;
}
return inodes_per_grp;
}
/* update the bitmap flags, set the itable high watermark, and calculate
* checksums for the group descriptors */
errcode_t ext2fs_set_gdt_csum(ext2_filsys fs)
{
struct ext2_super_block *sb = fs->super;
int dirty = 0;
dgrp_t i;
if (!fs->inode_map)
return EXT2_ET_NO_INODE_BITMAP;
if (!ext2fs_has_group_desc_csum(fs))
return 0;
for (i = 0; i < fs->group_desc_count; i++) {
__u32 old_csum = ext2fs_bg_checksum(fs, i);
__u32 old_unused = ext2fs_bg_itable_unused(fs, i);
__u32 old_flags = ext2fs_bg_flags(fs, i);
__u32 old_free_inodes_count = ext2fs_bg_free_inodes_count(fs, i);
__u32 old_free_blocks_count = ext2fs_bg_free_blocks_count(fs, i);
if (old_free_blocks_count == sb->s_blocks_per_group &&
i != fs->group_desc_count - 1)
ext2fs_bg_flags_set(fs, i, EXT2_BG_BLOCK_UNINIT);
if (old_free_inodes_count == sb->s_inodes_per_group) {
ext2fs_bg_flags_set(fs, i, EXT2_BG_INODE_UNINIT);
ext2fs_bg_itable_unused_set(fs, i, sb->s_inodes_per_group);
} else {
int unused =
sb->s_inodes_per_group -
find_last_inode_ingrp(fs->inode_map,
sb->s_inodes_per_group, i);
ext2fs_bg_flags_clear(fs, i, EXT2_BG_INODE_UNINIT);
ext2fs_bg_itable_unused_set(fs, i, unused);
}
ext2fs_group_desc_csum_set(fs, i);
if (old_flags != ext2fs_bg_flags(fs, i))
dirty = 1;
if (old_unused != ext2fs_bg_itable_unused(fs, i))
dirty = 1;
if (old_csum != ext2fs_bg_checksum(fs, i))
dirty = 1;
}
if (dirty)
ext2fs_mark_super_dirty(fs);
return 0;
}
#ifdef DEBUG
#include "e2p/e2p.h"
void print_csum(const char *msg, ext2_filsys fs, dgrp_t group)
{
__u16 crc1, crc2, crc3;
dgrp_t swabgroup;
struct ext2_group_desc *desc = ext2fs_group_desc(fs, fs->group_desc,
group);
size_t size = EXT2_DESC_SIZE(fs->super);
struct ext2_super_block *sb = fs->super;
int offset = offsetof(struct ext2_group_desc, bg_checksum);
#ifdef WORDS_BIGENDIAN
struct ext4_group_desc swabdesc;
struct ext2_group_desc *save_desc = desc;
const size_t ext4_bg_size = sizeof(struct ext4_group_desc);
size_t save_size = size;
#endif
#ifdef WORDS_BIGENDIAN
/* Have to swab back to little-endian to do the checksum */
if (size > ext4_bg_size)
size = ext4_bg_size;
memcpy(&swabdesc, desc, size);
ext2fs_swap_group_desc2(fs, (struct ext2_group_desc *) &swabdesc);
desc = (struct ext2_group_desc *) &swabdesc;
swabgroup = ext2fs_swab32(group);
#else
swabgroup = group;
#endif
crc1 = ext2fs_crc16(~0, sb->s_uuid, sizeof(fs->super->s_uuid));
crc2 = ext2fs_crc16(crc1, &swabgroup, sizeof(swabgroup));
crc3 = ext2fs_crc16(crc2, desc, offset);
offset += sizeof(desc->bg_checksum); /* skip checksum */
/* for checksum of struct ext4_group_desc do the rest...*/
if (offset < size)
crc3 = ext2fs_crc16(crc3, (char *)desc + offset, size - offset);
#ifdef WORDS_BIGENDIAN
if (save_size > ext4_bg_size)
crc3 = ext2fs_crc16(crc3, (char *)save_desc + ext4_bg_size,
save_size - ext4_bg_size);
#endif
printf("%s UUID %s=%04x, grp %u=%04x: %04x=%04x\n",
msg, e2p_uuid2str(sb->s_uuid), crc1, group, crc2, crc3,
ext2fs_group_desc_csum(fs, group));
}
unsigned char sb_uuid[16] = { 0x4f, 0x25, 0xe8, 0xcf, 0xe7, 0x97, 0x48, 0x23,
0xbe, 0xfa, 0xa7, 0x88, 0x4b, 0xae, 0xec, 0xdb };
int main(int argc, char **argv)
{
struct ext2_super_block param;
errcode_t retval;
ext2_filsys fs;
int i;
__u16 csum1, csum2, csum_known = 0xd3a4;
memset(¶m, 0, sizeof(param));
ext2fs_blocks_count_set(¶m, 32768);
#if 0
param.s_feature_incompat |= EXT4_FEATURE_INCOMPAT_64BIT;
param.s_desc_size = 128;
csum_known = 0x5b6e;
#endif
retval = ext2fs_initialize("test fs", EXT2_FLAG_64BITS, ¶m,
test_io_manager, &fs);
if (retval) {
com_err("setup", retval,
"While initializing filesystem");
exit(1);
}
memcpy(fs->super->s_uuid, sb_uuid, 16);
fs->super->s_feature_ro_compat = EXT4_FEATURE_RO_COMPAT_GDT_CSUM;
for (i=0; i < fs->group_desc_count; i++) {
ext2fs_block_bitmap_loc_set(fs, i, 124);
ext2fs_inode_bitmap_loc_set(fs, i, 125);
ext2fs_inode_table_loc_set(fs, i, 126);
ext2fs_bg_free_blocks_count_set(fs, i, 31119);
ext2fs_bg_free_inodes_count_set(fs, i, 15701);
ext2fs_bg_used_dirs_count_set(fs, i, 2);
ext2fs_bg_flags_zap(fs, i);
};
csum1 = ext2fs_group_desc_csum(fs, 0);
print_csum("csum0000", fs, 0);
if (csum1 != csum_known) {
printf("checksum for group 0 should be %04x\n", csum_known);
exit(1);
}
csum2 = ext2fs_group_desc_csum(fs, 1);
print_csum("csum0001", fs, 1);
if (csum1 == csum2) {
printf("checksums for different groups shouldn't match\n");
exit(1);
}
csum2 = ext2fs_group_desc_csum(fs, 2);
print_csum("csumffff", fs, 2);
if (csum1 == csum2) {
printf("checksums for different groups shouldn't match\n");
exit(1);
}
ext2fs_bg_checksum_set(fs, 0, csum1);
csum2 = ext2fs_group_desc_csum(fs, 0);
print_csum("csum_set", fs, 0);
if (csum1 != csum2) {
printf("checksums should not depend on checksum field\n");
exit(1);
}
if (!ext2fs_group_desc_csum_verify(fs, 0)) {
printf("checksums should verify against gd_checksum\n");
exit(1);
}
memset(fs->super->s_uuid, 0x30, sizeof(fs->super->s_uuid));
print_csum("new_uuid", fs, 0);
if (ext2fs_group_desc_csum_verify(fs, 0) != 0) {
printf("checksums for different filesystems shouldn't match\n");
exit(1);
}
csum1 = ext2fs_group_desc_csum(fs, 0);
ext2fs_bg_checksum_set(fs, 0, csum1);
print_csum("csum_new", fs, 0);
ext2fs_bg_free_blocks_count_set(fs, 0, 1);
csum2 = ext2fs_group_desc_csum(fs, 0);
print_csum("csum_blk", fs, 0);
if (csum1 == csum2) {
printf("checksums for different data shouldn't match\n");
exit(1);
}
return 0;
}
#endif