Re: [PATCH 1/2] pnfs/blocklayout: validate volume indices and limit recursion depth

[Christoph Hellwig <hch@lst.de>]

On Tue, Apr 21, 2026 at 10:03:42AM +0000, Werner Kasselman wrote:
>  #define PNFS_BLOCK_MAX_UUIDS	4
>  #define PNFS_BLOCK_MAX_DEVICES	64
> +#define PNFS_BLOCK_MAX_DEPTH	16

I think we can and should reduce the nesting depth.  The only really
useful nesting is mirroring + striping or concatenation.  Giving a little
extra slack is fine, but I think 4 (or 8 if you insist) should be
enough,

> +		int depth, gfp_t gfp_mask);

unsigned?

>  	default:
> @@ -559,6 +581,9 @@ bl_alloc_deviceid_node(struct nfs_server *server, struct pnfs_device *pdev,
>  		goto out_free_scratch;
>  	nr_volumes = be32_to_cpup(p++);
>  
> +	if (nr_volumes <= 0)
> +		goto out_free_scratch;

nr_volumes should be siwtched to an unsigned value, as it is over
the wire.

Otherwise looks good, thanks a lot!