Re: [PATCH 3/4] xfs: namecheck directory entry names before listing them

[Brian Foster <bfoster@redhat.com>]

On Thu, Oct 24, 2019 at 10:15:05PM -0700, Darrick J. Wong wrote:
> From: Darrick J. Wong <darrick.wong@oracle.com>
> 
> Actually call namecheck on directory entry names before we hand them
> over to userspace.
> 
> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
> ---
>  fs/xfs/xfs_dir2_readdir.c |   16 ++++++++++++++++
>  1 file changed, 16 insertions(+)
> 
> 
> diff --git a/fs/xfs/xfs_dir2_readdir.c b/fs/xfs/xfs_dir2_readdir.c
> index 283df898dd9f..a8fb0a6829fd 100644
> --- a/fs/xfs/xfs_dir2_readdir.c
> +++ b/fs/xfs/xfs_dir2_readdir.c
...
> @@ -208,6 +214,11 @@ xfs_dir2_block_getdents(
>  		/*
>  		 * If it didn't fit, set the final offset to here & return.
>  		 */
> +		if (!xfs_dir2_namecheck(dep->name, dep->namelen)) {
> +			XFS_ERROR_REPORT(__func__, XFS_ERRLEVEL_LOW,
> +					 dp->i_mount);
> +			return -EFSCORRUPTED;
> +		}

xfs_trans_brelse(..., bp) (here and in _leaf_getdents())?

Brian

>  		if (!dir_emit(ctx, (char *)dep->name, dep->namelen,
>  			    be64_to_cpu(dep->inumber),
>  			    xfs_dir3_get_dtype(dp->i_mount, filetype))) {
> @@ -456,6 +467,11 @@ xfs_dir2_leaf_getdents(
>  		filetype = dp->d_ops->data_get_ftype(dep);
>  
>  		ctx->pos = xfs_dir2_byte_to_dataptr(curoff) & 0x7fffffff;
> +		if (!xfs_dir2_namecheck(dep->name, dep->namelen)) {
> +			XFS_ERROR_REPORT(__func__, XFS_ERRLEVEL_LOW,
> +					 dp->i_mount);
> +			return -EFSCORRUPTED;
> +		}
>  		if (!dir_emit(ctx, (char *)dep->name, dep->namelen,
>  			    be64_to_cpu(dep->inumber),
>  			    xfs_dir3_get_dtype(dp->i_mount, filetype)))
>