The Study And Implementation Of Dynamic Injection Based On Linux

With the rapidly development of computer technology, computers, the Internet have been more and more closely related with our daily life. One hand, people enjoy the convenience brought from tremendous technological development, on the other hand, people also suffered from the invasion of malicious attacks and information distress. In this case, the security of the computer system is becoming the focus of attention and the search. Dynamic injection way in addition to used in the malicious attacks has been widely applied in hotfix for programs and automated testing.At present, the dynamic injection technology in such aspects as system upgrading, automated testing is widely used. But many users ultimately choose to give up this technology, the main reason is that the dynamic injection in test automation integration is low, dynamic process of injection can make goals do not match the environment before and after injection, and dynamic injection efficiency is low. So we need to design a secure and efficient plan for dynamic injection, which can achieve the process context. In this paper, the main research contents and research results are as follows: 1. Based on the existing research of injection mechanism, we proposes a new basic model of dynamic injection mechanism. The model includes an injection tool, a boarding procedure, a target process, and the final result. Dynamic injection process with the information which boarding program and the process of target provide, analyze the correlation of the boarding procedure and the target process, function analysis, and redirect operation. Dynamic injection process through the process of target information to complete the process orientation, process analysis and process recovery operation. Therefore the design of system framework mainly includes: the design of boarding program data interface, the design of the process of dynamic injection and the design of the process of target information acquisition and so on.The design of the boarding program of data mainly includes the design of the boarding program compiled way and the design of the data interface. 2. On the basis of the above basic model, it has been refined into a simple dynamic injection mechanism and refine the system model for engineering implementation. The process of dynamic injection through boarding program to provide relevant data and the process of target information complete boarding procedures and target process correlation analysis, function analysis and redirection, and so on. On boarding program compilation of design, use position-independent code technology, realize the boarding program code and data address references. On boarding program of data interface design, boarding program of data interface for injection tools provide the following information: boarding program process associated with the target indicator, the newly created or modify type of the data of the boarding program, boarding process variables to define the scope of the operator, the newly created boarding program function, the function in the boarding program symbols. 3. On the basis of the above system model, a kind of dynamic injection tools has been realized. After studying Linux memory management, Linux process information and dynamic linking principle. The process of target information acquisition is mainly to use utrace system call interface, through this system call to attach the target process, and will process the relevant stack, general-purpose registers and other information stored in the definition of data structure. Needed the information of memory mapping of the target process, information obtained through utrace boarding procedure dlopen and positioning function of symbol resolution work. 4. For the implementation of dynamic injection tools, testing environment based on Linux should be built, on the functional testing and verification, the result of the test are briefly analyzed.