diff options
Diffstat (limited to 'lib/ext2fs/csum.c')
| -rw-r--r-- | lib/ext2fs/csum.c | 1011 |
1 files changed, 1011 insertions, 0 deletions
diff --git a/lib/ext2fs/csum.c b/lib/ext2fs/csum.c new file mode 100644 index 0000000..da32d94 --- /dev/null +++ b/lib/ext2fs/csum.c @@ -0,0 +1,1011 @@ +/* + * 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) || + ext2fs_has_feature_ea_inode(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); + + if (fs->blocksize < 1024) + return EXT2_FILSYS_CORRUPTED; /* Should never happen */ + + d = dirent; + top = EXT2_DIRENT_TAIL(dirent, fs->blocksize); + + while ((void *) d < top) { + rec_len = translate(d->rec_len); + if ((rec_len < 8) || (rec_len & 0x03)) + return EXT2_ET_DIR_CORRUPTED; + d = (struct ext2_dir_entry *)(((char *)d) + rec_len); + } + + if ((char *)d > ((char *)dirent + fs->blocksize)) + return EXT2_ET_DIR_CORRUPTED; + 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) != + EXT2_ET_DIR_NO_SPACE_FOR_CSUM; +} + +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; +} + +errcode_t ext2fs_dx_csum(ext2_filsys fs, ext2_ino_t inum, + struct ext2_dir_entry *dirent, + __u32 *crc, struct ext2_dx_tail **ret_t) +{ + errcode_t retval; + char *buf = (char *)dirent; + int size; + __u32 gen, dummy_csum = 0; + struct ext2_inode inode; + struct ext2_dx_tail *t; + struct ext2_dx_countlimit *c; + 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; + /* htree structs are accessed in LE order */ + t = (struct ext2_dx_tail *)(((struct ext2_dx_entry *)c) + limit); + + size = count_offset + (count * sizeof(struct ext2_dx_entry)); + + 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, 4); + *crc = ext2fs_crc32c_le(*crc, (unsigned char *)&dummy_csum, 4); + + if (ret_t) + *ret_t = t; + 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_tail *t; + + retval = ext2fs_dx_csum(fs, inum, dirent, &calculated, &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_tail *t; + + retval = ext2fs_dx_csum(fs, inum, dirent, &crc, &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 (EXT2_DESC_SIZE(fs->super) >= 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 (EXT2_DESC_SIZE(fs->super) >= 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 (EXT2_DESC_SIZE(fs->super) >= 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 (EXT2_DESC_SIZE(fs->super) >= 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 = EXT2_INODE_SIZE(fs->super); + __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); + } + ext2fs_free(fs); + + return 0; +} +#endif |