Re: [PATCH 1/1] NFSD: detect mismatch of file handle and delegation stateid in OPEN op

[Jeff Layton <jlayton@kernel.org>]

On Tue, 2025-06-10 at 06:41 -0700, Dai Ngo wrote:
> When the client sends an OPEN with claim type CLAIM_DELEG_CUR_FH or
> CLAIM_DELEGATION_CUR, the delegation stateid and the file handle
> must belongs to the same file, otherwise return NFS4ERR_BAD_STATEID.
> 
> Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
> ---
>  fs/nfsd/nfs4state.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
> index 59a693f22452..be2ee641a22d 100644
> --- a/fs/nfsd/nfs4state.c
> +++ b/fs/nfsd/nfs4state.c
> @@ -6318,6 +6318,11 @@ nfsd4_process_open2(struct svc_rqst *rqstp, struct svc_fh *current_fh, struct nf
>  		status = nfs4_check_deleg(cl, open, &dp);
>  		if (status)
>  			goto out;
> +		if (dp && nfsd4_is_deleg_cur(open) &&
> +				(dp->dl_stid.sc_file != fp)) {
> +			status = nfserr_bad_stateid;
> +			goto out;
> +		}
>  		stp = nfsd4_find_and_lock_existing_open(fp, open);
>  	} else {
>  		open->op_file = NULL;

This seems like a good idea. I wonder if BAD_STATEID is the right error
here. It is a valid stateid, after all, it just doesn't match the
current_fh. Maybe this should be nfserr_inval ?

In any case, whatever we decide:

Reviewed-by: Jeff Layton <jlayton@kernel.org>