NFS: Fix filehandle size comparisons in the mount code

Fix a sign issue in xdr_decode_fhstatus3()
Fix incorrect comparison in nfs_validate_mount_data()
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

fs/nfs/mount_clnt.c

@@ -130,10 +130,11 @@ static int xdr_decode_fhstatus3(struct rpc_rqst *req, __be32 *p,
 				struct mnt_fhstatus *res)
 {
 	struct nfs_fh *fh = res->fh;
+	unsigned size;
 
 	if ((res->status = ntohl(*p++)) == 0) {
-		int size = ntohl(*p++);
-		if (size <= NFS3_FHSIZE) {
+		size = ntohl(*p++);
+		if (size <= NFS3_FHSIZE && size != 0) {
 			fh->size = size;
 			memcpy(fh->data, p, size);
 		} else

fs/nfs/super.c

@@ -1249,13 +1249,13 @@ static int nfs_validate_mount_data(void *options,
 	case 5:
 		memset(data->context, 0, sizeof(data->context));
 	case 6:
-		if (data->flags & NFS_MOUNT_VER3)
+		if (data->flags & NFS_MOUNT_VER3) {
+			if (data->root.size > NFS3_FHSIZE || data->root.size == 0)
+				goto out_invalid_fh;
 			mntfh->size = data->root.size;
-		else
+		} else
 			mntfh->size = NFS2_FHSIZE;
 
-		if (mntfh->size > sizeof(mntfh->data))
-			goto out_invalid_fh;
 
 		memcpy(mntfh->data, data->root.data, mntfh->size);
 		if (mntfh->size < sizeof(mntfh->data))