NFSD enforce filehandle check for source file in COPY

[ Upstream commit 754035ff79 ]

If the passed in filehandle for the source file in the COPY operation
is not a regular file, the server MUST return NFS4ERR_WRONG_TYPE.

Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
[ cel: adjusted to apply to v5.15.y ]
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

fs/nfsd/nfs4proc.c

@@ -1760,7 +1760,13 @@ static int nfsd4_do_async_copy(void *data)
 		filp = nfs42_ssc_open(copy->ss_mnt, &copy->c_fh,
 				      &copy->stateid);
 		if (IS_ERR(filp)) {
-			nfserr = nfserr_offload_denied;
+			switch (PTR_ERR(filp)) {
+			case -EBADF:
+				nfserr = nfserr_wrong_type;
+				break;
+			default:
+				nfserr = nfserr_offload_denied;
+			}
 			/* ss_mnt will be unmounted by the laundromat */
 			goto do_callback;
 		}