This patch adds the ability for the libext2fs functions to read and write the
inode checksum. It also fixes a few fields that were omitted from the byte
swapping routines.
Signed-off-by: Darrick J. Wong <djwong@xxxxxxxxxx>
---
lib/ext2fs/csum.c | 95 +++++++++++++++++++++++++++++++++++++++++++++
lib/ext2fs/ext2_err.et.in | 9 ++++
lib/ext2fs/ext2_fs.h | 5 ++
lib/ext2fs/ext2fs.h | 4 ++
lib/ext2fs/inode.c | 46 +++++++++++++++++-----
5 files changed, 148 insertions(+), 11 deletions(-)
diff --git a/lib/ext2fs/csum.c b/lib/ext2fs/csum.c
index 596923e..b8945ad 100644
--- a/lib/ext2fs/csum.c
+++ b/lib/ext2fs/csum.c
@@ -30,6 +30,101 @@
#define STATIC static
#endif
+static errcode_t ext2fs_inode_csum(ext2_filsys fs, ext2_ino_t inum,
+ struct ext2_inode_large *inode,
+ __u32 *crc)
+{
+ __u32 ncrc;
+ struct ext2_inode_large *desc = inode;
+ size_t size = fs->super->s_inode_size;
+ __u16 old_lo;
+ __u16 old_hi;
+ errcode_t retval = 0;
+
+ old_lo = inode->i_checksum_lo;
+ inode->i_checksum_lo = 0;
+ if (EXT2_INODE_SIZE(fs->super) > EXT2_GOOD_OLD_INODE_SIZE &&
+ inode->i_extra_isize >= EXT4_INODE_CSUM_HI_EXTRA_LOCATION) {
+ old_hi = inode->i_checksum_hi;
+ inode->i_checksum_hi = 0;
+ }
+
+#ifdef WORDS_BIGENDIAN
+ struct ext2_inode_large *swabinode;
+ retval = ext2fs_get_mem(size, &swabinode);
+ if (retval)
+ goto err;
+
+ /* Have to swab back to little-endian to do the checksum */
+ memcpy(swabinode, inode, size);
+ ext2fs_swap_inode_full(fs, swabinode, swabinode, 1, size);
+ desc = swabinode;
+#endif
+
+ inum = ext2fs_cpu_to_le32(inum);
+ ncrc = ext2fs_crc32c_le(~0, fs->super->s_uuid,
+ sizeof(fs->super->s_uuid));
+ ncrc = ext2fs_crc32c_le(ncrc, (unsigned char *)&inum, sizeof(inum));
+ ncrc = ext2fs_crc32c_le(ncrc, (unsigned char *)desc, size);
+ *crc = ncrc;
+
+#ifdef WORDS_BIGENDIAN
+ ext2fs_free_mem(&swabinode);
+err:
+#endif
+
+ inode->i_checksum_lo = old_lo;
+ if (EXT2_INODE_SIZE(fs->super) > EXT2_GOOD_OLD_INODE_SIZE &&
+ inode->i_extra_isize >= EXT4_INODE_CSUM_HI_EXTRA_LOCATION)
+ inode->i_checksum_hi = old_hi;
+ return retval;
+}
+
+int ext2fs_inode_csum_verify(ext2_filsys fs, ext2_ino_t inum,
+ struct ext2_inode_large *inode)
+{
+ errcode_t retval;
+ __u32 provided, calculated;
+
+ if (fs->super->s_creator_os != EXT2_OS_LINUX ||
+ !EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
+ EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
+ return 1;
+
+ provided = inode->i_checksum_lo;
+ retval = ext2fs_inode_csum(fs, inum, inode, &calculated);
+ if (retval)
+ return 0;
+ if (EXT2_INODE_SIZE(fs->super) > EXT2_GOOD_OLD_INODE_SIZE &&
+ inode->i_extra_isize >= EXT4_INODE_CSUM_HI_EXTRA_LOCATION)
+ provided |= ((__u32)inode->i_checksum_hi) << 16;
+ else
+ calculated &= 0xFFFF;
+
+ return provided == calculated;
+}
+
+errcode_t ext2fs_inode_csum_set(ext2_filsys fs, ext2_ino_t inum,
+ struct ext2_inode_large *inode)
+{
+ errcode_t retval;
+ __u32 crc;
+
+ if (fs->super->s_creator_os != EXT2_OS_LINUX ||
+ !EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
+ EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
+ return 0;
+
+ retval = ext2fs_inode_csum(fs, inum, inode, &crc);
+ if (retval)
+ return retval;
+ inode->i_checksum_lo = crc & 0xFFFF;
+ if (EXT2_INODE_SIZE(fs->super) > EXT2_GOOD_OLD_INODE_SIZE &&
+ inode->i_extra_isize >= EXT4_INODE_CSUM_HI_EXTRA_LOCATION)
+ inode->i_checksum_hi = crc >> 16;
+ return 0;
+}
+
STATIC __u16 ext2fs_group_desc_csum(ext2_filsys fs, dgrp_t group)
{
__u16 crc = 0;
diff --git a/lib/ext2fs/ext2_err.et.in b/lib/ext2fs/ext2_err.et.in
index e759b6f..fa66b85 100644
--- a/lib/ext2fs/ext2_err.et.in
+++ b/lib/ext2fs/ext2_err.et.in
@@ -443,4 +443,13 @@ ec EXT2_ET_MMP_CHANGE_ABORT,
ec EXT2_ET_MMP_OPEN_DIRECT,
"MMP: open with O_DIRECT failed"
+ec EXT2_ET_INODE_CSUM_INVALID,
+ "Inode checksum is incorrect"
+
+ec EXT2_ET_INODE_CORRUPT,
+ "Inode checksum indicates corruption"
+
+ec EXT2_ET_INODE_CSUM_NONZERO,
+ "Inode checksum should not be set"
+
end
diff --git a/lib/ext2fs/ext2_fs.h b/lib/ext2fs/ext2_fs.h
index 0f8cde8..6fd82f1 100644
--- a/lib/ext2fs/ext2_fs.h
+++ b/lib/ext2fs/ext2_fs.h
@@ -452,6 +452,10 @@ struct ext2_inode_large {
__u32 i_version_hi; /* high 32 bits for 64-bit version */
};
+#define EXT4_INODE_CSUM_HI_EXTRA_LOCATION \
+ (offsetof(struct ext2_inode_large, i_checksum_hi) + sizeof(__u16) - \
+ EXT2_GOOD_OLD_INODE_SIZE)
+
#define i_dir_acl i_size_high
#if defined(__KERNEL__) || defined(__linux__)
@@ -462,6 +466,7 @@ struct ext2_inode_large {
#define i_gid_low i_gid
#define i_uid_high osd2.linux2.l_i_uid_high
#define i_gid_high osd2.linux2.l_i_gid_high
+#define i_checksum_lo osd2.linux2.l_i_checksum_lo
#else
#if defined(__GNU__)
diff --git a/lib/ext2fs/ext2fs.h b/lib/ext2fs/ext2fs.h
index 4a3e7af..04db632 100644
--- a/lib/ext2fs/ext2fs.h
+++ b/lib/ext2fs/ext2fs.h
@@ -925,6 +925,10 @@ extern __u32 ext2fs_crc32c_be(__u32 crc, unsigned char const *p, size_t len);
extern __u32 ext2fs_crc32c_le(__u32 crc, unsigned char const *p, size_t len);
/* csum.c */
+extern errcode_t ext2fs_inode_csum_set(ext2_filsys fs, ext2_ino_t inum,
+ struct ext2_inode_large *inode);
+extern int ext2fs_inode_csum_verify(ext2_filsys fs, ext2_ino_t inum,
+ struct ext2_inode_large *inode);
extern void ext2fs_group_desc_csum_set(ext2_filsys fs, dgrp_t group);
extern int ext2fs_group_desc_csum_verify(ext2_filsys fs, dgrp_t group);
extern errcode_t ext2fs_set_gdt_csum(ext2_filsys fs);
diff --git a/lib/ext2fs/inode.c b/lib/ext2fs/inode.c
index 7b0db60..6236976 100644
--- a/lib/ext2fs/inode.c
+++ b/lib/ext2fs/inode.c
@@ -417,7 +417,7 @@ errcode_t ext2fs_get_next_inode_full(ext2_inode_scan scan, ext2_ino_t *ino,
errcode_t retval;
int extra_bytes = 0;
const int length = EXT2_INODE_SIZE(scan->fs->super);
- struct ext2_inode *iptr = inode;
+ struct ext2_inode_large *iptr = (struct ext2_inode_large *)inode;
EXT2_CHECK_MAGIC(scan, EXT2_ET_MAGIC_INODE_SCAN);
@@ -521,11 +521,18 @@ errcode_t ext2fs_get_next_inode_full(ext2_inode_scan scan, ext2_ino_t *ino,
retval = EXT2_ET_BAD_BLOCK_IN_INODE_TABLE;
}
+ /* Verify the inode checksum. */
+ if (!(scan->fs->flags & EXT2_FLAG_IGNORE_CSUM_ERRORS) &&
+ !ext2fs_inode_csum_verify(scan->fs, scan->current_inode, iptr))
+ retval = EXT2_ET_INODE_CSUM_INVALID;
+
scan->inodes_left--;
scan->current_inode++;
*ino = scan->current_inode;
- if (inode != iptr) {
- memcpy(inode, iptr, bufsize);
+
+ if (iptr != (struct ext2_inode_large *)inode) {
+ if (!retval)
+ memcpy(inode, iptr, bufsize);
ext2fs_free_mem(&iptr);
}
return retval;
@@ -547,11 +554,11 @@ errcode_t ext2fs_read_inode_full(ext2_filsys fs, ext2_ino_t ino,
blk64_t block_nr;
unsigned long group, block, offset;
char *ptr;
- errcode_t retval;
+ errcode_t retval = 0;
int clen, i, inodes_per_block;
io_channel io;
int length = EXT2_INODE_SIZE(fs->super);
- struct ext2_inode *iptr = inode;
+ struct ext2_inode_large *iptr = (struct ext2_inode_large *)inode;
EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
@@ -633,6 +640,12 @@ errcode_t ext2fs_read_inode_full(ext2_filsys fs, ext2_ino_t ino,
(struct ext2_inode_large *) iptr,
0, length);
#endif
+ /* Verify the inode checksum. */
+ if (!(fs->flags & EXT2_FLAG_IGNORE_CSUM_ERRORS) &&
+ !ext2fs_inode_csum_verify(fs, ino, iptr)) {
+ retval = EXT2_ET_INODE_CSUM_INVALID;
+ goto err;
+ }
/* Update the inode cache */
fs->icache->cache_last = (fs->icache->cache_last + 1) %
@@ -640,12 +653,14 @@ errcode_t ext2fs_read_inode_full(ext2_filsys fs, ext2_ino_t ino,
fs->icache->cache[fs->icache->cache_last].ino = ino;
memcpy(fs->icache->cache[fs->icache->cache_last].inode, iptr, length);
- if (iptr != inode) {
- memcpy(inode, iptr, bufsize);
+err:
+ if (iptr != (struct ext2_inode_large *)inode) {
+ if (!retval)
+ memcpy(inode, iptr, bufsize);
ext2fs_free_mem(&iptr);
}
- return 0;
+ return retval;
}
errcode_t ext2fs_read_inode(ext2_filsys fs, ext2_ino_t ino,
@@ -682,12 +697,17 @@ errcode_t ext2fs_write_inode_full(ext2_filsys fs, ext2_ino_t ino,
retval = ext2fs_get_mem(length, &w_inode);
if (retval)
return retval;
- if (bufsize < length)
+
+ if (bufsize < length) {
+ int old_flags = fs->flags;
+ fs->flags |= EXT2_FLAG_IGNORE_CSUM_ERRORS;
retval = ext2fs_read_inode_full(fs, ino,
(struct ext2_inode *)w_inode,
length);
- if (retval)
- goto errout;
+ fs->flags = old_flags;
+ if (retval)
+ goto errout;
+ }
/* Check to see if the inode cache needs to be updated */
if (fs->icache) {
@@ -710,6 +730,10 @@ errcode_t ext2fs_write_inode_full(ext2_filsys fs, ext2_ino_t ino,
goto errout;
}
+ retval = ext2fs_inode_csum_set(fs, ino, w_inode);
+ if (retval)
+ goto errout;
+
#ifdef WORDS_BIGENDIAN
ext2fs_swap_inode_full(fs, w_inode, w_inode, 1, length);
#endif
--
To unsubscribe from this list: send the line "unsubscribe linux-ext4" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
