target: Add missing mapped_lun bounds checking during make_mappedlun setup

This patch adds missing bounds checking for the configfs provided
mapped_lun value during target_fabric_make_mappedlun() setup ahead
of se_lun_acl initialization.

This addresses a potential OOPs when using a mapped_lun value that
exceeds the hardcoded TRANSPORT_MAX_LUNS_PER_TPG-1 value within
se_node_acl->device_list[].

Reported-by: Jan Engelhardt <jengelh@inai.de>
Cc: Jan Engelhardt <jengelh@inai.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

drivers/target/target_core_fabric_configfs.c

@@ -354,6 +354,14 @@ static struct config_group *target_fabric_make_mappedlun(
 		ret = -EINVAL;
 		goto out;
 	}
+	if (mapped_lun > (TRANSPORT_MAX_LUNS_PER_TPG-1)) {
+		pr_err("Mapped LUN: %lu exceeds TRANSPORT_MAX_LUNS_PER_TPG"
+			"-1: %u for Target Portal Group: %u\n", mapped_lun,
+			TRANSPORT_MAX_LUNS_PER_TPG-1,
+			se_tpg->se_tpg_tfo->tpg_get_tag(se_tpg));
+		ret = -EINVAL;
+		goto out;
+	}
 
 	lacl = core_dev_init_initiator_node_lun_acl(se_tpg, se_nacl,
 			mapped_lun, &ret);