Received-SPF: pass (google.com: domain of linux-ext4-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Subject: Re: [PATCH 10/11] fs: remove the access_ok() check in ioctl_fiemap
To:     Christoph Hellwig <hch@lst.de>, linux-ext4@vger.kernel.org,
        viro@zeniv.linux.org.uk
Cc:     jack@suse.cz, tytso@mit.edu, adilger@dilger.ca, amir73il@gmail.com,
        linux-fsdevel@vger.kernel.org, linux-unionfs@vger.kernel.org
References: <20200427181957.1606257-1-hch@lst.de>
 <20200427181957.1606257-11-hch@lst.de>
From:   Ritesh Harjani <riteshh@linux.ibm.com>
Date:   Sat, 2 May 2020 04:26:34 +0530
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101
 Thunderbird/60.7.2
MIME-Version: 1.0
In-Reply-To: <20200427181957.1606257-11-hch@lst.de>
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Language: en-US
Content-Transfer-Encoding: 7bit
Message-Id: <20200501225635.2DFA4AE045@d06av26.portsmouth.uk.ibm.com>
Sender: linux-ext4-owner@vger.kernel.org
Precedence: bulk


On 4/27/20 11:49 PM, 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.

Ok.

> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Looks fine. Feel free to add
Reviewed-by: Ritesh Harjani <riteshh@linux.ibm.com>


> ---
>   fs/ioctl.c | 6 +-----
>   1 file changed, 1 insertion(+), 5 deletions(-)
> 
> diff --git a/fs/ioctl.c b/fs/ioctl.c
> index ae0d228d18a16..d24afce649037 100644
> --- a/fs/ioctl.c
> +++ b/fs/ioctl.c
> @@ -209,13 +209,9 @@ static int ioctl_fiemap(struct file *filp, struct fiemap __user *ufiemap)
>   	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 = inode->i_op->fiemap(inode, &fieinfo, fiemap.fm_start,
>   			fiemap.fm_length);
> +
>   	fiemap.fm_flags = fieinfo.fi_flags;
>   	fiemap.fm_mapped_extents = fieinfo.fi_extents_mapped;
>   	if (copy_to_user(ufiemap, &fiemap, sizeof(fiemap)))
>