diff --git a/drivers/scsi/libiscsi.c b/drivers/scsi/libiscsi.c
index 82c3fd4..1243d2f 100644
--- a/drivers/scsi/libiscsi.c
+++ b/drivers/scsi/libiscsi.c
@@ -718,11 +718,21 @@
 			return NULL;
 		}
 
+		if (data_size > ISCSI_DEF_MAX_RECV_SEG_LEN) {
+			iscsi_conn_printk(KERN_ERR, conn, "Invalid buffer len of %u for login task. Max len is %u\n", data_size, ISCSI_DEF_MAX_RECV_SEG_LEN);
+			return NULL;
+		}
+
 		task = conn->login_task;
 	} else {
 		if (session->state != ISCSI_STATE_LOGGED_IN)
 			return NULL;
 
+		if (data_size != 0) {
+			iscsi_conn_printk(KERN_ERR, conn, "Can not send data buffer of len %u for op 0x%x\n", data_size, opcode);
+			return NULL;
+		}
+
 		BUG_ON(conn->c_stage == ISCSI_CONN_INITIAL_STAGE);
 		BUG_ON(conn->c_stage == ISCSI_CONN_STOPPED);