[PATCH 003/119] xfs: check offsets of variable length structures

Darrick J. Wong
2016-06-17T01:18:20Z

Some of the directory/attr structures contain variable-length objects,
so the enclosing structure doesn't have a meaningful fixed size at
compile time. We can check the offsets of the members before the
variable-length member, so do those.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
fs/xfs/xfs_ondisk.h | 25 +++++++++++++++++++++++--
1 file changed, 23 insertions(+), 2 deletions(-)

diff --git a/fs/xfs/xfs_ondisk.h b/fs/xfs/xfs_ondisk.h
index 184c44e..0272301 100644
--- a/fs/xfs/xfs_ondisk.h
+++ b/fs/xfs/xfs_ondisk.h
@@ -22,6 +22,11 @@
BUILD_BUG_ON_MSG(sizeof(structname) != (size), "XFS: sizeof(" \
#structname ") is wrong, expected " #size)

+#define XFS_CHECK_OFFSET(structname, member, off) \
+ BUILD_BUG_ON_MSG(offsetof(structname, member) != (off), \
+ "XFS: offsetof(" #structname ", " #member ") is wrong, " \
+ "expected " #off)
+
static inline void __init
xfs_check_ondisk_structs(void)
{
@@ -75,15 +80,28 @@ xfs_check_ondisk_structs(void)
XFS_CHECK_STRUCT_SIZE(xfs_attr_leaf_name_remote_t, 12);
*/

+ XFS_CHECK_OFFSET(xfs_attr_leaf_name_local_t, valuelen, 0);
+ XFS_CHECK_OFFSET(xfs_attr_leaf_name_local_t, namelen, 2);
+ XFS_CHECK_OFFSET(xfs_attr_leaf_name_local_t, nameval, 3);
+ XFS_CHECK_OFFSET(xfs_attr_leaf_name_remote_t, valueblk, 0);
+ XFS_CHECK_OFFSET(xfs_attr_leaf_name_remote_t, valuelen, 4);
+ XFS_CHECK_OFFSET(xfs_attr_leaf_name_remote_t, namelen, 8);
+ XFS_CHECK_OFFSET(xfs_attr_leaf_name_remote_t, name, 9);
XFS_CHECK_STRUCT_SIZE(xfs_attr_leafblock_t, 40);
- XFS_CHECK_STRUCT_SIZE(xfs_attr_shortform_t, 8);
+ XFS_CHECK_OFFSET(xfs_attr_shortform_t, hdr.totsize, 0);
+ XFS_CHECK_OFFSET(xfs_attr_shortform_t, hdr.count, 2);
+ XFS_CHECK_OFFSET(xfs_attr_shortform_t, list[0].namelen, 4);
+ XFS_CHECK_OFFSET(xfs_attr_shortform_t, list[0].valuelen, 5);
+ XFS_CHECK_OFFSET(xfs_attr_shortform_t, list[0].flags, 6);
+ XFS_CHECK_OFFSET(xfs_attr_shortform_t, list[0].nameval, 7);
XFS_CHECK_STRUCT_SIZE(xfs_da_blkinfo_t, 12);
XFS_CHECK_STRUCT_SIZE(xfs_da_intnode_t, 16);
XFS_CHECK_STRUCT_SIZE(xfs_da_node_entry_t, 8);
XFS_CHECK_STRUCT_SIZE(xfs_da_node_hdr_t, 16);
XFS_CHECK_STRUCT_SIZE(xfs_dir2_data_free_t, 4);
XFS_CHECK_STRUCT_SIZE(xfs_dir2_data_hdr_t, 16);
- XFS_CHECK_STRUCT_SIZE(xfs_dir2_data_unused_t, 6);
+ XFS_CHECK_OFFSET(xfs_dir2_data_unused_t, freetag, 0);
+ XFS_CHECK_OFFSET(xfs_dir2_data_unused_t, length, 2);
XFS_CHECK_STRUCT_SIZE(xfs_dir2_free_hdr_t, 16);
XFS_CHECK_STRUCT_SIZE(xfs_dir2_free_t, 16);
XFS_CHECK_STRUCT_SIZE(xfs_dir2_ino4_t, 4);
@@ -94,6 +112,9 @@ xfs_check_ondisk_structs(void)
XFS_CHECK_STRUCT_SIZE(xfs_dir2_leaf_t, 16);
XFS_CHECK_STRUCT_SIZE(xfs_dir2_leaf_tail_t, 4);
XFS_CHECK_STRUCT_SIZE(xfs_dir2_sf_entry_t, 3);
+ XFS_CHECK_OFFSET(xfs_dir2_sf_entry_t, namelen, 0);
+ XFS_CHECK_OFFSET(xfs_dir2_sf_entry_t, offset, 1);
+ XFS_CHECK_OFFSET(xfs_dir2_sf_entry_t, name, 3);
XFS_CHECK_STRUCT_SIZE(xfs_dir2_sf_hdr_t, 10);
XFS_CHECK_STRUCT_SIZE(xfs_dir2_sf_off_t, 2);