Gain insights into using GDB for debugging in Linux. Explore disassembly, memory investigation, and register updates. Learn about pointers, stack, and function parameters in x64 architecture.

gdb.tar.gz

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GNU Debugger (GDB) is used for debugging C/C++ programs in LINUX/UNIX environments. It is a good tool to investigate what is happening inside a program, and how the contents inside the memory are changed with the execution of the program.

The main focus of the course is the disassembly of the program, where we'll use simple operations in C. With the help of GDB, we'll examine the contents of the registers and memory. We'll also learn how they are changed while executing basic operations. We’ll then explore the use of pointers, stack, and function parameters, and analyze how different registers update their values. With the help of disassembly output, we’ll learn how a simple C program can be reconstructed. The disassembly output is important for debugging and core dump analysis. We’ll use assembly language for x64 architecture.

By the end of this course, you should be able to debug the programs and memory contents at assembly level when a program executes or probe into the problem when a program crashes.

Debugging, Disassembly & Reversing in Linux for x64 Architecture

# A definition
The concept of a **pointer** is one of the most important to understand thoroughly if you want to master **Linux debugging**. By definition, a pointer is *a memory cell or a processor register that contains the address of another memory cell*, as shown in the image below. It has its own address as any memory cell. Sometimes, a pointer is called an **indirect address** (vs. a direct address, the address of a memory cell). 

Iteratively, we can add another level of indirection and introduce a **pointer to a pointer** as a memory cell or a processor register. This second pointer  contains the address of another memory cell that contains the address of another memory cell, and so on.

Learn how to use pointers to address memory and perform arithmetic calculations.

A Definition of Pointers

Introduction to Pointers

Introduction to the Course

Memory, Registers, and Simple Arithmetic

Code Optimization

Number Representations

Pointers

Bytes, Words, Double, and Quad Words

Pointers to Memory

Logical Instructions and RIP

Reconstructing a Program with Pointers

Memory and Stacks

Frame Pointer and Local Variables

Function Parameters

More Instructions

Function Pointer Parameters

Summary of Code Disassembly Patterns

x64 Debugging, Disassembly & Reversing Exam

Introduction to Pointers