Good Programming and the Rules for Writing Secure Code

Welcome to the first in a series of articles about writing secure code for the Win32 API, specifically for Windows 2000 (Win2K) and Windows NT. Although some of the topics also pertain to Windows 9x, these systems don't have the rich set of security features provided by the Windows NT-based line of OSs, so some columns in this series won’t apply.

In this column, I'll focus on writing secure code using C and C++ because I'm most familiar with these programming languages. In addition, Microsoft used C and C++ to write Windows 2000 and Windows NT, and you can most easily access some of the OSs' security features using these languages. Finally, these languages are also the ones developers most commonly use to code commercial software.

So why not discuss Java or Visual Basic (VB)? Both languages make writing secure code easy by properly bounds-checking arrays, and Java has the nice automatic garbage-collection feature. To some extent, my choice to focus on C and C++ is personal preference because only these languages provide such speed and full access to system calls that I use on a daily basis. Unfortunately, one of the reasons C and C++ executables provide such speed is because these languages give you plenty of room to shoot yourself in the foot. A friend of mine once said that if C lets programmers shoot themselves in the foot, then C++ just gives them a machine gun! My experience is that poorly written C++ code is often worse than poorly written C code. However, C++ provides some convenient features and lets you write code that is better organized. I encourage anyone entering a career as a developer to learn C++ thoroughly. This education is essential to learning Distributed COM (DCOM), which developers are increasingly using to interface with Win2K and NT.

Finding Resources
The discussions in this column assume that you have some fundamental familiarity with basic programming techniques. If you’re new to programming in C or C++, I recommend that you start with a good reference. One of the best titles available is A Book on C: Programming in C by Al Kelly and Ira Pohl (ISBN: 0201183994). Another good reference is C: A Reference Manual by Samuel Harbison and Guy Steele (ISBN: 0133262243). Ira Pohl has also authored some excellent books on C++, and if you’re learning C++, make sure you spend some time getting to know the standard template library (STL). STL simplifies many difficult tasks—once you get past the learning curve. If you're already familiar with coding basics, a great reference that will improve your coding skills is Writing Solid Code by Steve Macguire (ISBN: 1556155514). Even if you’ve been programming in C for 15 years, this book is worth reading. Some of the best programmers I know have told me that they’ve learned from this text, and it's essential to anyone starting out. . . .