[PATCH 02/16] nvme-core: Refuse out-of-range integrity data seeds

[keith.busch@intel.com (Keith Busch)]

On Mon, Oct 08, 2018@02:28:40PM -0700, Bart Van Assche wrote:
> The nvme_user_io.slba field is 64 bits wide. That value is copied into the
> 32-bit bio_integrity_payload.bip_iter.bi_sector field. Refuse slba values
> that exceed 32 bits. This patch avoids that Coverity complains about
> implicit truncation. See also Coverity ID 1056486 on
> http://scan.coverity.com/projects/linux.
> 
> Signed-off-by: Bart Van Assche <bvanassche at acm.org>
> ---
>  drivers/nvme/host/core.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
> index 63932dea74a1..04138223fad6 100644
> --- a/drivers/nvme/host/core.c
> +++ b/drivers/nvme/host/core.c
> @@ -1118,6 +1118,14 @@ static int nvme_submit_io(struct nvme_ns *ns, struct nvme_user_io __user *uio)
>  			return -EINVAL;
>  	}
>  
> +	/*
> +	 * io.slba is 64 bits wide. Only the lower 32 bits are used as a seed.
> +	 * Refuse seed values that exceed 32 bits instead of truncating the
> +	 * seed value silently. See also nvme_add_user_metadata().
> +	 */
> +	if (io.slba >> 32 != 0)
> +		return -EINVAL;
> +
>  	memset(&c, 0, sizeof(c));
>  	c.rw.opcode = io.opcode;
>  	c.rw.flags = io.flags;

The bip sector is supposed to wrap if it exceeds 32 bits. Just feed
"lower_32_bits(io.slba)" as the metadata seed.