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

[Hannes Reinecke]

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 at 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 at suse.de>

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                  Kernel Storage Architect
hare at suse.de                                +49 911 74053 688
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