Re: [PATCH] xfs: check for negatives in xfs_exchange_range_checks()

[Darrick J. Wong]

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@xxxxxxxxxx>
> ---
> 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@xxxxxxxxxx>

--D


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