1. The operating system provides the trusted path to prevent unauthorized programs from reading data from a user terminal
2. secure attention key (SAK), which establishes the environment necessary for secure communication between you and the system
3. TPE(Trusted Path Execution)
   1. SELinux already supports TPE functionalities
4. A trusted path is known as one of classic protection mechanisms in a security model. It is in short a mechanism to make sure that a user can access the trusted software without being compromised by other processes or users, and to make sure that the software runs correctly as really intended. Some standards and papers ([1], [2]) give a more formal definition of the term. One concept trying to provide a trusted mechanism with the main purpose of preventing arbitrary users from executing arbitrary code is usually called Trusted Path Execution, or TPE for short.
5. In kernel space, a basic funtion to check if a path is protected or not is already available in LIDS. Thus the task is to create functions that include the basic function and decide where and when we must do the permission checking.
6. Linux Security Modules (LSM)
7. The Linux Security Modules (LSM) framework is a set of authorization hooks for implementing flexible access control in the Linux kernel. While much effort has been devoted to defining the module interfaces, little attention has been paid to verifying the correctness of hook placement. This paper presents a novel approach to the verification of LSM authorization hook placement using CQUAL, a type-based static analysis tool. With a simple CQUAL lattice configuration and some GCC-based analyses, we are able to verify complete mediation of operations on key kernel data structures. Our results reveal some potential security vulnerabilities of the current LSM framework, one of which we demonstrate to be exploitable. Our experiences demonstrate that combinations of conceptually simple tools can be used to perform fairly complex analyses.