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Commit 3c6f46ea authored by Amir Goldstein's avatar Amir Goldstein Committed by Darrick J. Wong
Browse files

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: default avatarDarrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarAmir Goldstein <amir73il@gmail.com>
Reviewed-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
parent bf46ecc3

fs/xfs/libxfs/xfs_dir2.c

+2 −1
Original line number Diff line number Diff line
@@ -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;

}

fs/xfs/libxfs/xfs_inode_buf.c

+5 −2
Original line number Diff line number Diff line
@@ -386,6 +386,7 @@ xfs_dinode_verify( 
	xfs_ino_t		ino,

	struct xfs_dinode	*dip)

{

	uint16_t		mode;

	uint16_t		flags;

	uint64_t		flags2;
@@ -396,8 +397,10 @@ xfs_dinode_verify( 
	if (be64_to_cpu(dip->di_size) & (1ULL << 63))

		return false;



	/* No zero-length symlinks. */

	if (S_ISLNK(be16_to_cpu(dip->di_mode)) && dip->di_size == 0)

	mode = be16_to_cpu(dip->di_mode);



	/* No zero-length symlinks/dirs. */

	if ((S_ISLNK(mode) || S_ISDIR(mode)) && dip->di_size == 0)

		return false;



	/* only version 3 or greater inodes are extensively verified here */