This patch adds the ability for the libext2fs functions to read and write the
inode checksum.
Signed-off-by: Darrick J. Wong <djwong@xxxxxxxxxx>
---
lib/ext2fs/csum.c | 82 +++++++++++++++++++++++++++++++++++++++++++++
lib/ext2fs/ext2_err.et.in | 3 ++
lib/ext2fs/ext2_fs.h | 4 ++
lib/ext2fs/ext2fs.h | 4 ++
lib/ext2fs/inode.c | 40 ++++++++++++++++++----
lib/ext2fs/mkdir.c | 8 +++-
6 files changed, 131 insertions(+), 10 deletions(-)
diff --git a/lib/ext2fs/csum.c b/lib/ext2fs/csum.c
index 596923e..5091a00 100644
--- a/lib/ext2fs/csum.c
+++ b/lib/ext2fs/csum.c
@@ -30,6 +30,88 @@
#define STATIC static
#endif
+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;
+ int has_hi;
+
+ if (fs->super->s_creator_os != EXT2_OS_LINUX ||
+ !EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
+ EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
+ 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;
+
+ 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;
+ int has_hi;
+
+ if (fs->super->s_creator_os != EXT2_OS_LINUX ||
+ !EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
+ EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
+ 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;
+}
+
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 ccf1894..d4a5b10 100644
--- a/lib/ext2fs/ext2_err.et.in
+++ b/lib/ext2fs/ext2_err.et.in
@@ -443,4 +443,7 @@ 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 does not match inode"
+
end
diff --git a/lib/ext2fs/ext2_fs.h b/lib/ext2fs/ext2_fs.h
index b0b798b..3ec48a2 100644
--- a/lib/ext2fs/ext2_fs.h
+++ b/lib/ext2fs/ext2_fs.h
@@ -460,6 +460,10 @@ struct ext2_inode_large {
__u32 i_version_hi; /* high 32 bits for 64-bit version */
};
+#define EXT4_INODE_CSUM_HI_EXTRA_END \
+ (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__)
diff --git a/lib/ext2fs/ext2fs.h b/lib/ext2fs/ext2fs.h
index f7a73e5..1728599 100644
--- a/lib/ext2fs/ext2fs.h
+++ b/lib/ext2fs/ext2fs.h
@@ -948,6 +948,10 @@ 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 a4f6670..74703c5 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);
@@ -493,6 +493,12 @@ errcode_t ext2fs_get_next_inode_full(ext2_inode_scan scan, ext2_ino_t *ino,
scan->ptr += scan->inode_size - extra_bytes;
scan->bytes_left -= scan->inode_size - extra_bytes;
+ /* Verify the inode checksum. */
+ if (!(scan->fs->flags & EXT2_FLAG_IGNORE_CSUM_ERRORS) &&
+ !ext2fs_inode_csum_verify(scan->fs, scan->current_inode + 1,
+ (struct ext2_inode_large *)scan->temp_buffer))
+ retval = EXT2_ET_INODE_CSUM_INVALID;
+
#ifdef WORDS_BIGENDIAN
memset(iptr, 0, length);
ext2fs_swap_inode_full(scan->fs,
@@ -506,6 +512,12 @@ errcode_t ext2fs_get_next_inode_full(ext2_inode_scan scan, ext2_ino_t *ino,
retval = EXT2_ET_BAD_BLOCK_IN_INODE_TABLE;
scan->scan_flags &= ~EXT2_SF_BAD_EXTRA_BYTES;
} else {
+ /* Verify the inode checksum. */
+ if (!(scan->fs->flags & EXT2_FLAG_IGNORE_CSUM_ERRORS) &&
+ !ext2fs_inode_csum_verify(scan->fs, scan->current_inode + 1,
+ (struct ext2_inode_large *)scan->ptr))
+ retval = EXT2_ET_INODE_CSUM_INVALID;
+
#ifdef WORDS_BIGENDIAN
memset(iptr, 0, length);
ext2fs_swap_inode_full(scan->fs,
@@ -524,7 +536,7 @@ errcode_t ext2fs_get_next_inode_full(ext2_inode_scan scan, ext2_ino_t *ino,
scan->inodes_left--;
scan->current_inode++;
*ino = scan->current_inode;
- if (inode != iptr) {
+ if (iptr != (struct ext2_inode_large *)inode) {
memcpy(inode, iptr, bufsize);
ext2fs_free_mem(&iptr);
}
@@ -551,7 +563,7 @@ errcode_t ext2fs_read_inode_full(ext2_filsys fs, ext2_ino_t ino,
int clen, i, inodes_per_block;
io_channel io;
int length = EXT2_INODE_SIZE(fs->super);
- struct ext2_inode *iptr;
+ struct ext2_inode_large *iptr;
int cache_slot;
EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
@@ -600,7 +612,7 @@ errcode_t ext2fs_read_inode_full(ext2_filsys fs, ext2_ino_t ino,
offset &= (EXT2_BLOCK_SIZE(fs->super) - 1);
cache_slot = (fs->icache->cache_last + 1) % fs->icache->cache_size;
- iptr = fs->icache->cache[cache_slot].inode;
+ iptr = (struct ext2_inode_large *)fs->icache->cache[cache_slot].inode;
ptr = (char *) iptr;
while (length) {
@@ -626,6 +638,11 @@ errcode_t ext2fs_read_inode_full(ext2_filsys fs, ext2_ino_t ino,
}
length = EXT2_INODE_SIZE(fs->super);
+ /* Verify the inode checksum. */
+ if (!(fs->flags & EXT2_FLAG_IGNORE_CSUM_ERRORS) &&
+ !ext2fs_inode_csum_verify(fs, ino, iptr))
+ return EXT2_ET_INODE_CSUM_INVALID;
+
#ifdef WORDS_BIGENDIAN
ext2fs_swap_inode_full(fs, (struct ext2_inode_large *) iptr,
(struct ext2_inode_large *) iptr,
@@ -674,12 +691,17 @@ 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) {
@@ -706,6 +728,10 @@ errcode_t ext2fs_write_inode_full(ext2_filsys fs, ext2_ino_t ino,
ext2fs_swap_inode_full(fs, w_inode, w_inode, 1, length);
#endif
+ retval = ext2fs_inode_csum_set(fs, ino, w_inode);
+ if (retval)
+ goto errout;
+
group = (ino - 1) / EXT2_INODES_PER_GROUP(fs->super);
offset = ((ino - 1) % EXT2_INODES_PER_GROUP(fs->super)) *
EXT2_INODE_SIZE(fs->super);
diff --git a/lib/ext2fs/mkdir.c b/lib/ext2fs/mkdir.c
index b12bf2d..861ddab 100644
--- a/lib/ext2fs/mkdir.c
+++ b/lib/ext2fs/mkdir.c
@@ -93,12 +93,14 @@ errcode_t ext2fs_mkdir(ext2_filsys fs, ext2_ino_t parent, ext2_ino_t inum,
inode.i_size = fs->blocksize;
/*
- * Write out the inode and inode data block
+ * Write out the inode and inode data block. The inode generation
+ * number is assigned by write_new_inode, which means that the call
+ * to write_dir_block must come after that.
*/
- retval = ext2fs_write_dir_block(fs, blk, block);
+ retval = ext2fs_write_new_inode(fs, ino, &inode);
if (retval)
goto cleanup;
- retval = ext2fs_write_new_inode(fs, ino, &inode);
+ retval = ext2fs_write_dir_block(fs, blk, block);
if (retval)
goto cleanup;
--
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