RDMA/rtrs: Do not allow sessname to contain special symbols / and .

Allowing these characters in sessname can lead to unexpected results,
particularly because / is used as a separator between files in a path, and
. points to the current directory.

Link: https://lore.kernel.org/r/20210922125333.351454-7-haris.iqbal@ionos.comSigned-off-by: Md Haris Iqbal <haris.iqbal@ionos.com>
Reviewed-by: Gioh Kim <gi-oh.kim@ionos.com>
Reviewed-by: Aleksei Marov <aleksei.marov@ionos.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

drivers/infiniband/ulp/rtrs/rtrs-clt.c

@@ -2788,6 +2788,12 @@ struct rtrs_clt *rtrs_clt_open(struct rtrs_clt_ops *ops,
 	struct rtrs_clt *clt;
 	int err, i;
 
+	if (strchr(sessname, '/') || strchr(sessname, '.')) {
+		pr_err("sessname cannot contain / and .\n");
+		err = -EINVAL;
+		goto out;
+	}
+
 	clt = alloc_clt(sessname, paths_num, port, pdu_sz, ops->priv,
 			ops->link_ev,
 			reconnect_delay_sec,

drivers/infiniband/ulp/rtrs/rtrs-srv.c

@@ -803,6 +803,11 @@ static int process_info_req(struct rtrs_srv_con *con,
 		return err;
 	}
 
+	if (strchr(msg->sessname, '/') || strchr(msg->sessname, '.')) {
+		rtrs_err(s, "sessname cannot contain / and .\n");
+		return -EINVAL;
+	}
+
 	if (exist_sessname(sess->srv->ctx,
 			   msg->sessname, &sess->srv->paths_uuid)) {
 		rtrs_err(s, "sessname is duplicated: %s\n", msg->sessname);