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Date: Tue, 7 May 2024 16:33:39 -0700
From: "Darrick J. Wong" <djwong@kernel.org>
To: Dan Carpenter <dan.carpenter@linaro.org>
Cc: Chandan Babu R <chandan.babu@oracle.com>, linux-xfs@vger.kernel.org,
	linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org
Subject: Re: [PATCH] xfs: check for negatives in xfs_exchange_range_checks()
Message-ID: <20240507233339.GY360919@frogsfrogsfrogs>
References: <0e7def98-1479-4f3a-a69a-5f4d09e12fa8@moroto.mountain>
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In-Reply-To: <0e7def98-1479-4f3a-a69a-5f4d09e12fa8@moroto.mountain>

On Sat, May 04, 2024 at 02:27:36PM +0300, Dan Carpenter wrote:
> The fxr->file1_offset and fxr->file2_offset variables come from the user
> in xfs_ioc_exchange_range().  They are size loff_t which is an s64.
> Check the they aren't negative.
> 
> Fixes: 9a64d9b3109d ("xfs: introduce new file range exchange ioctl")
> Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
> ---
> From static analysis.  Untested.  Sorry!

Not a fan of this        ^^^^^^^^

> 
>  fs/xfs/xfs_exchrange.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/fs/xfs/xfs_exchrange.c b/fs/xfs/xfs_exchrange.c
> index c8a655c92c92..3465e152d928 100644
> --- a/fs/xfs/xfs_exchrange.c
> +++ b/fs/xfs/xfs_exchrange.c
> @@ -337,6 +337,9 @@ xfs_exchange_range_checks(
>  	if (IS_SWAPFILE(inode1) || IS_SWAPFILE(inode2))
>  		return -ETXTBSY;
>  
> +	if (fxr->file1_offset < 0 || fxr->file2_offset < 0)
> +		return -EINVAL;

but this looks right to me.

If you actually test your changes, then
Reviewed-by: Darrick J. Wong <djwong@kernel.org>

--D


> +
>  	size1 = i_size_read(inode1);
>  	size2 = i_size_read(inode2);
>  
> -- 
> 2.43.0
> 
>