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

From: Darrick J. Wong
Date: Tue May 07 2024 - 20:04:06 EST


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
>
>