Verify and calculate extent tree block checksums when processing filesystems.
Signed-off-by: Darrick J. Wong <djwong@xxxxxxxxxx>
---
lib/ext2fs/csum.c | 79 +++++++++++++++++++++++++++++++++++++++++++++
lib/ext2fs/ext2_err.et.in | 3 ++
lib/ext2fs/ext2fs.h | 6 +++
lib/ext2fs/extent.c | 21 ++++++++++++
4 files changed, 109 insertions(+), 0 deletions(-)
diff --git a/lib/ext2fs/csum.c b/lib/ext2fs/csum.c
index 5c5b7fb..8a0543c 100644
--- a/lib/ext2fs/csum.c
+++ b/lib/ext2fs/csum.c
@@ -30,6 +30,85 @@
#define STATIC static
#endif
+#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 *)(((void *)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 (!EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
+ EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
+ 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 (!EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
+ EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
+ 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)
{
diff --git a/lib/ext2fs/ext2_err.et.in b/lib/ext2fs/ext2_err.et.in
index 3f5d08f..9019026 100644
--- a/lib/ext2fs/ext2_err.et.in
+++ b/lib/ext2fs/ext2_err.et.in
@@ -449,4 +449,7 @@ ec EXT2_ET_INODE_CSUM_INVALID,
ec EXT2_ET_INODE_BITMAP_CSUM_INVALID,
"Inode bitmap checksum does not match bitmap"
+ec EXT2_ET_EXTENT_CSUM_INVALID,
+ "Extent block checksum does not match extent block"
+
end
diff --git a/lib/ext2fs/ext2fs.h b/lib/ext2fs/ext2fs.h
index 9d3e8c9..8dd038a 100644
--- a/lib/ext2fs/ext2fs.h
+++ b/lib/ext2fs/ext2fs.h
@@ -952,6 +952,12 @@ 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_extent_block_csum_set(ext2_filsys fs,
+ ext2_ino_t inum,
+ struct ext3_extent_header *eh);
+extern int ext2fs_extent_block_csum_verify(ext2_filsys fs,
+ ext2_ino_t inum,
+ struct ext3_extent_header *eh);
extern errcode_t ext2fs_block_bitmap_csum_set(ext2_filsys fs, dgrp_t group,
char *bitmap, int size);
extern int ext2fs_block_bitmap_csum_verify(ext2_filsys fs, dgrp_t group,
diff --git a/lib/ext2fs/extent.c b/lib/ext2fs/extent.c
index eb096d6..7d456ef 100644
--- a/lib/ext2fs/extent.c
+++ b/lib/ext2fs/extent.c
@@ -455,6 +455,13 @@ retry:
return retval;
}
+ if (!(handle->fs->flags & EXT2_FLAG_IGNORE_CSUM_ERRORS) &&
+ !ext2fs_extent_block_csum_verify(handle->fs, handle->ino,
+ eh)) {
+ handle->level--;
+ return EXT2_ET_EXTENT_CSUM_INVALID;
+ }
+
newpath->left = newpath->entries =
ext2fs_le16_to_cpu(eh->eh_entries);
newpath->max_entries = ext2fs_le16_to_cpu(eh->eh_max);
@@ -541,6 +548,7 @@ static errcode_t update_path(ext2_extent_handle_t handle)
blk64_t blk;
errcode_t retval;
struct ext3_extent_idx *ix;
+ struct ext3_extent_header *eh;
if (handle->level == 0) {
retval = ext2fs_write_inode(handle->fs, handle->ino,
@@ -550,6 +558,14 @@ static errcode_t update_path(ext2_extent_handle_t handle)
blk = ext2fs_le32_to_cpu(ix->ei_leaf) +
((__u64) ext2fs_le16_to_cpu(ix->ei_leaf_hi) << 32);
+ /* then update the checksum */
+ eh = (struct ext3_extent_header *)
+ handle->path[handle->level].buf;
+ retval = ext2fs_extent_block_csum_set(handle->fs, handle->ino,
+ eh);
+ if (retval)
+ return retval;
+
retval = io_channel_write_blk64(handle->fs->io,
blk, 1, handle->path[handle->level].buf);
}
@@ -958,6 +974,11 @@ static errcode_t extent_node_split(ext2_extent_handle_t handle)
new_node_start = ext2fs_le32_to_cpu(EXT_FIRST_INDEX(neweh)->ei_block);
+ /* then update the checksum */
+ retval = ext2fs_extent_block_csum_set(handle->fs, handle->ino, neweh);
+ if (retval)
+ goto done;
+
/* ...and write the new node block out to disk. */
retval = io_channel_write_blk64(handle->fs->io, new_node_pblk, 1,
block_buf);
--
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
