Re: [PATCH 2/4] nvme: reject invalid pr_read_keys() num_keys values

Hannes Reinecke
2025-11-27T07:02:30Z

On 11/26/25 17:35, Stefan Hajnoczi wrote:
> The pr_read_keys() interface has a u32 num_keys parameter. The NVMe
> Reservation Report command has a u32 maximum length. Reject num_keys
> values that are too large to fit.
>
> This will become important when pr_read_keys() is exposed to untrusted
> userspace via an <linux/pr.h> ioctl.
>
> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
> ---
> drivers/nvme/host/pr.c | 5 +++++
> 1 file changed, 5 insertions(+)
>
> diff --git a/drivers/nvme/host/pr.c b/drivers/nvme/host/pr.c
> index ca6a74607b139..476a0518a11ca 100644
> --- a/drivers/nvme/host/pr.c
> +++ b/drivers/nvme/host/pr.c
> @@ -233,6 +233,11 @@ static int nvme_pr_read_keys(struct block_device *bdev,
> int ret, i;
> bool eds;
>
> + /* Check that keys fit into u32 rse_len */
> + if (num_keys > -(u32)offsetof(typeof(*rse), regctl_eds) /
> + sizeof(rse->regctl_eds[0]))
> + return -EINVAL;
> +
> /*
> * Assume we are using 128-bit host IDs and allocate a buffer large
> * enough to get enough keys to fill the return keys buffer.

Reviewed-by: Hannes Reinecke <hare@suse.de>

Cheers,

Hannes
--
Dr. Hannes Reinecke Kernel Storage Architect
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