Re: [PATCH 3/4] xfs: refactor file range validation

[Brian Foster <bfoster@redhat.com>]

On Sun, Dec 06, 2020 at 03:11:09PM -0800, Darrick J. Wong wrote:
> From: Darrick J. Wong <darrick.wong@oracle.com>
> 
> Refactor all the open-coded validation of file block ranges into a
> single helper, and teach the bmap scrubber to check the ranges.
> 
> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
> ---

Reviewed-by: Brian Foster <bfoster@redhat.com>

>  fs/xfs/libxfs/xfs_bmap.c  |    2 +-
>  fs/xfs/libxfs/xfs_types.c |   25 +++++++++++++++++++++++++
>  fs/xfs/libxfs/xfs_types.h |    3 +++
>  fs/xfs/scrub/bmap.c       |    4 ++++
>  fs/xfs/xfs_bmap_item.c    |    2 +-
>  fs/xfs/xfs_rmap_item.c    |    2 +-
>  6 files changed, 35 insertions(+), 3 deletions(-)
> 
> 
> diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c
> index 7bcf498ef6b2..dcf56bcafb8f 100644
> --- a/fs/xfs/libxfs/xfs_bmap.c
> +++ b/fs/xfs/libxfs/xfs_bmap.c
> @@ -6227,7 +6227,7 @@ xfs_bmap_validate_extent(
>  {
>  	struct xfs_mount	*mp = ip->i_mount;
>  
> -	if (irec->br_startoff + irec->br_blockcount <= irec->br_startoff)
> +	if (!xfs_verify_fileext(mp, irec->br_startoff, irec->br_blockcount))
>  		return __this_address;
>  
>  	if (XFS_IS_REALTIME_INODE(ip) && whichfork == XFS_DATA_FORK) {
> diff --git a/fs/xfs/libxfs/xfs_types.c b/fs/xfs/libxfs/xfs_types.c
> index 7b310eb296b7..b254fbeaaa50 100644
> --- a/fs/xfs/libxfs/xfs_types.c
> +++ b/fs/xfs/libxfs/xfs_types.c
> @@ -258,3 +258,28 @@ xfs_verify_dablk(
>  
>  	return dabno <= max_dablk;
>  }
> +
> +/* Check that a file block offset does not exceed the maximum. */
> +bool
> +xfs_verify_fileoff(
> +	struct xfs_mount	*mp,
> +	xfs_fileoff_t		off)
> +{
> +	return off <= XFS_MAX_FILEOFF;
> +}
> +
> +/* Check that a range of file block offsets do not exceed the maximum. */
> +bool
> +xfs_verify_fileext(
> +	struct xfs_mount	*mp,
> +	xfs_fileoff_t		off,
> +	xfs_fileoff_t		len)
> +{
> +	if (off + len <= off)
> +		return false;
> +
> +	if (!xfs_verify_fileoff(mp, off))
> +		return false;
> +
> +	return xfs_verify_fileoff(mp, off + len - 1);
> +}
> diff --git a/fs/xfs/libxfs/xfs_types.h b/fs/xfs/libxfs/xfs_types.h
> index 18e83ce46568..064bd6e8c922 100644
> --- a/fs/xfs/libxfs/xfs_types.h
> +++ b/fs/xfs/libxfs/xfs_types.h
> @@ -203,5 +203,8 @@ bool xfs_verify_icount(struct xfs_mount *mp, unsigned long long icount);
>  bool xfs_verify_dablk(struct xfs_mount *mp, xfs_fileoff_t off);
>  void xfs_icount_range(struct xfs_mount *mp, unsigned long long *min,
>  		unsigned long long *max);
> +bool xfs_verify_fileoff(struct xfs_mount *mp, xfs_fileoff_t off);
> +bool xfs_verify_fileext(struct xfs_mount *mp, xfs_fileoff_t off,
> +		xfs_fileoff_t len);
>  
>  #endif	/* __XFS_TYPES_H__ */
> diff --git a/fs/xfs/scrub/bmap.c b/fs/xfs/scrub/bmap.c
> index cce8ac7d3973..bce4421acdb9 100644
> --- a/fs/xfs/scrub/bmap.c
> +++ b/fs/xfs/scrub/bmap.c
> @@ -329,6 +329,10 @@ xchk_bmap_iextent(
>  		xchk_fblock_set_corrupt(info->sc, info->whichfork,
>  				irec->br_startoff);
>  
> +	if (!xfs_verify_fileext(mp, irec->br_startoff, irec->br_blockcount))
> +		xchk_fblock_set_corrupt(info->sc, info->whichfork,
> +				irec->br_startoff);
> +
>  	xchk_bmap_dirattr_extent(ip, info, irec);
>  
>  	/* There should never be a "hole" extent in either extent list. */
> diff --git a/fs/xfs/xfs_bmap_item.c b/fs/xfs/xfs_bmap_item.c
> index 5c9706760e68..9a2e54b7ccb9 100644
> --- a/fs/xfs/xfs_bmap_item.c
> +++ b/fs/xfs/xfs_bmap_item.c
> @@ -449,7 +449,7 @@ xfs_bui_validate(
>  	if (!xfs_verify_ino(mp, bmap->me_owner))
>  		return false;
>  
> -	if (bmap->me_startoff + bmap->me_len <= bmap->me_startoff)
> +	if (!xfs_verify_fileext(mp, bmap->me_startoff, bmap->me_len))
>  		return false;
>  
>  	return xfs_verify_fsbext(mp, bmap->me_startblock, bmap->me_len);
> diff --git a/fs/xfs/xfs_rmap_item.c b/fs/xfs/xfs_rmap_item.c
> index 4fa875237422..49cebd68b672 100644
> --- a/fs/xfs/xfs_rmap_item.c
> +++ b/fs/xfs/xfs_rmap_item.c
> @@ -490,7 +490,7 @@ xfs_rui_validate_map(
>  	    !xfs_verify_ino(mp, rmap->me_owner))
>  		return false;
>  
> -	if (rmap->me_startoff + rmap->me_len <= rmap->me_startoff)
> +	if (!xfs_verify_fileext(mp, rmap->me_startoff, rmap->me_len))
>  		return false;
>  
>  	return xfs_verify_fsbext(mp, rmap->me_startblock, rmap->me_len);
>