Re: [PATCH] block: add allocation size check in blkdev_pr_read_keys()

From: Christoph Hellwig

Date: Mon Dec 15 2025 - 00:34:02 EST


On Fri, Dec 12, 2025 at 08:17:43PM +0530, Deepanshu Kartikey wrote:
> How about limiting num_keys to 64K (1u << 16)? In practice, PR keys
> are used for shared storage coordination and typical deployments have
> only a handful of hosts, so this should be more than enough for any
> realistic use case.
>
> With a bounded num_keys, the SIZE_MAX check becomes unnecessary, so
> I've removed it. Also switched to kvzalloc/kvfree to handle larger
> allocations gracefully.
>
> Something like below:
>
> +/* Limit the number of keys to prevent excessive memory allocation */
> +#define PR_KEYS_MAX_NUM (1u << 16)

Looks reasonable to me. Stefan?