linux-ext4 - Re: [PATCH 11/11] ext4: remove the access_ok() check in ext4_ioctl_get_es

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Date:   Wed, 6 May 2020 11:32:38 +0200
From:   Jan Kara <jack@...e.cz>
To:     Christoph Hellwig <hch@....de>
Cc:     linux-ext4@...r.kernel.org, viro@...iv.linux.org.uk, jack@...e.cz,
        tytso@....edu, adilger@...ger.ca, riteshh@...ux.ibm.com,
        amir73il@...il.com, linux-fsdevel@...r.kernel.org,
        linux-unionfs@...r.kernel.org
Subject: Re: [PATCH 11/11] ext4: remove the access_ok() check in
 ext4_ioctl_get_es_cache

On Tue 05-05-20 17:43:24, Christoph Hellwig wrote:
> access_ok just checks we are fed a proper user pointer.  We also do that
> in copy_to_user itself, so no need to do this early.
> 
> Signed-off-by: Christoph Hellwig <hch@....de>
> Reviewed-by: Ritesh Harjani <riteshh@...ux.ibm.com>

Looks good to me. You can add:

Reviewed-by: Jan Kara <jack@...e.cz>

								Honza

> ---
>  fs/ext4/ioctl.c | 5 -----
>  1 file changed, 5 deletions(-)
> 
> diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c
> index f81acbbb1b12e..2162db0c747d2 100644
> --- a/fs/ext4/ioctl.c
> +++ b/fs/ext4/ioctl.c
> @@ -754,11 +754,6 @@ static int ext4_ioctl_get_es_cache(struct file *filp, unsigned long arg)
>  	fieinfo.fi_extents_max = fiemap.fm_extent_count;
>  	fieinfo.fi_extents_start = ufiemap->fm_extents;
>  
> -	if (fiemap.fm_extent_count != 0 &&
> -	    !access_ok(fieinfo.fi_extents_start,
> -		       fieinfo.fi_extents_max * sizeof(struct fiemap_extent)))
> -		return -EFAULT;
> -
>  	error = ext4_get_es_cache(inode, &fieinfo, fiemap.fm_start,
>  			fiemap.fm_length);
>  	fiemap.fm_flags = fieinfo.fi_flags;
> -- 
> 2.26.2
> 
-- 
Jan Kara <jack@...e.com>
SUSE Labs, CR