xfs: sanity check directory inode di_size
This changes fixes an assertion hit when fuzzing on-disk
i_mode values.
The easy case to fix is when changing an empty file
i_mode to S_IFDIR. In this case, xfs_dinode_verify()
detects an illegal zero size for directory and fails
to load the inode structure from disk.
For the case of non empty file whose i_mode is changed
to S_IFDIR, the ASSERT() statement in xfs_dir2_isblock()
is replaced with return -EFSCORRUPTED, to avoid interacting
with corrupted jusk also when XFS_DEBUG is disabled.
Suggested-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
diff --git a/fs/xfs/libxfs/xfs_dir2.c b/fs/xfs/libxfs/xfs_dir2.c
index c58d72c..4f7913f 100644
--- a/fs/xfs/libxfs/xfs_dir2.c
+++ b/fs/xfs/libxfs/xfs_dir2.c
@@ -631,7 +631,8 @@ xfs_dir2_isblock(
if ((rval = xfs_bmap_last_offset(args->dp, &last, XFS_DATA_FORK)))
return rval;
rval = XFS_FSB_TO_B(args->dp->i_mount, last) == args->geo->blksize;
- ASSERT(rval == 0 || args->dp->i_d.di_size == args->geo->blksize);
+ if (rval != 0 && args->dp->i_d.di_size != args->geo->blksize)
+ return -EFSCORRUPTED;
*vp = rval;
return 0;
}